CA1058467A - Syringe pump valving and motor direction control system - Google Patents
Syringe pump valving and motor direction control systemInfo
- Publication number
- CA1058467A CA1058467A CA228,728A CA228728A CA1058467A CA 1058467 A CA1058467 A CA 1058467A CA 228728 A CA228728 A CA 228728A CA 1058467 A CA1058467 A CA 1058467A
- Authority
- CA
- Canada
- Prior art keywords
- tube
- slide bar
- cam
- syringe
- pinchers
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M39/00—Tubes, tube connectors, tube couplings, valves, access sites or the like, specially adapted for medical use
- A61M39/22—Valves or arrangement of valves
- A61M39/28—Clamping means for squeezing flexible tubes, e.g. roller clamps
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/142—Pressure infusion, e.g. using pumps
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S128/00—Surgery
- Y10S128/12—Pressure infusion
Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates generally to improvements in an improved valve control system for syringe pumps. Prior art syringe pumps are often overly complex and unstable or inaccurate in their valving and motor control systems. The present invention overcomes these deficiencies by providing apparatus which repetitively and sequentially opens and closes a pair of intake and output I.V. tubes communicating with a syringe, the tubes alternating opened and closed states, one tube always being open while the other is closed, by means of a pair of L-shaped pivotal tube pinchers, one pincher controlling each I.V. tube, each pincher being normally spring biased to the tube clamping shut-off state. The tube pinchers are alternately pivoted to a non-clamping, tube-open position by a spring biased, intermittent motion, reciprocating slide bar under the control of a reversible, rotating cam, the cam being driven by the same motor as that used to drive the piston of the syringe through its fill and pump strokes. A photoelectric sensor is responsive to the physical position of one of the tube pinchers and generates an electrical signal to control the direction of motor rotation and, hence, determines whether the syringe pump performs a fill stroke or a pump stroke.
This invention relates generally to improvements in an improved valve control system for syringe pumps. Prior art syringe pumps are often overly complex and unstable or inaccurate in their valving and motor control systems. The present invention overcomes these deficiencies by providing apparatus which repetitively and sequentially opens and closes a pair of intake and output I.V. tubes communicating with a syringe, the tubes alternating opened and closed states, one tube always being open while the other is closed, by means of a pair of L-shaped pivotal tube pinchers, one pincher controlling each I.V. tube, each pincher being normally spring biased to the tube clamping shut-off state. The tube pinchers are alternately pivoted to a non-clamping, tube-open position by a spring biased, intermittent motion, reciprocating slide bar under the control of a reversible, rotating cam, the cam being driven by the same motor as that used to drive the piston of the syringe through its fill and pump strokes. A photoelectric sensor is responsive to the physical position of one of the tube pinchers and generates an electrical signal to control the direction of motor rotation and, hence, determines whether the syringe pump performs a fill stroke or a pump stroke.
Description
~058467 Thi3 inventlon relates generally to improvement~
in syringe pumps and, more partlcularly, to a new and lm-proved valve control sy~tem for such pump~ whlch reliably and preci~ely opens and clo~es the intake and output I.V.
tubes for a syrlnge at approprlate polnts ln the pumping cycle and also generates a control slgnal for ~stabll~hlng dire¢tion of motor rotatlon.
The usual medical procedure for the gradual par-enteral adm$nist~ation o~ liquid~ lnto the human body, ~u~h a~ llquid nutrlent~, blood or plasma, make~ use of appara-tu3 whlch 1~ commonly re~erred to in the medlcal arts as an intravenou~ admlnlstratlon ~et. The lntravenou~ set usu-ally comprlses a bottle Or li~uid, normally supported ln ; an lnverted position, an intravenou~ ~eeding tube, typi-cally Or alear pla3tlc, and a sultable valve mechanlsm, such as a roll clamp, which allow~ the liquid to drlp out Or th~ bottle at a selectlvely ad~ustable rate into a tran3parent drip chamber below the bottle. ~he drlp cham-ber serve~ the dual runctlon Or allowln~ a nurse or other 20 attendant to ob3erve the rate at which the llquld drip~ out Or the bottle, and al~o creates a reservoir ror the liquld at the lower end Or the drlp chamber to in~ure th~t no alr enters the main reeding tube leading to the patlent.
Whlle ob~ervation o~ the rate of drop rlow via the drip chamber 18 a simple way of controlllng the amount o~ liquid fed to a patient over a perlod o~ time, its ultl-mate ef~ectiveness requlre~ that a relatively constant vlgil be maintalned on the drop flo~, le~t it cea~e en-tlrely due to exhau~tion o~ the liquid supplied or b~come 30 a continuous stream and perhaps increa~e the rate of liquld introductlon to the patlent to dangerou~ levels.
~ y way Or example, lt ha~ been the general prac-tlce ln hospltals to have nur~e3 periodlcally monltor drop ~OS8467 flow rate ~t each intravenous feedlng or parenteral ln-fusion ~tation. Such monitorlng of drop flow 18 a tedlous, and tlme consumlng process, prone to error and assoclated, po~lbly serlous consequence~, and resultlng ln a substan-tial reduction o~ the avallable tlme o~ quall~ied medical personnel ~or other lmportant dutle~. Typl¢ally, the nurse monitorlng drop ~low rate will use a watoh to tlme the number of drops ~lowlng in an interval of one or more minutes, and she will then mentally perform the mathe-matics necessary to convert the ob~erved data to an appro-priate fluld flow rate, e.g., in drops per mlnute. If the calculated ~low rate i8 sub~tantlally different than the prescribed rateJ the nur~e must manually ad~ust the roll clamp ~or a new rate, count drop~ again, and re¢alcu-late to measure the new flow rate.
Obvlou~ly, each of the aforedescribed mea~urements, calculatlons and flow rate ad~ustments usually take sever-al minute~ tlme whlch, when multlplled by the number of statlons belng monltored and the number of tlmes eaoh ~-station ~hould be monltored per day, ¢an re~ult ln a sub-stantlal percentage of total personnel time available. In addition, under the pressure of a heavy ~chedule, the ob-~ervations and calculatlons performed by a harrled nurse in measurlng and ad~usting flow rate may not always prove to be reliable and, hence, errors do oocur re~ulting in undeslred, possibly dangerous lnfu~lon flow rates.
In addition to the aforedescrlbed dl~flcultles, the parenteral admlnl~tratlon of medical liquids by gravity - lnduced hydrostatic pres~ure lnfu~ion o~ the llquid from a ; 30 bottle or other container suspended above the patient, 1 very susceptible to fluid flow rate variation due to changes ln the liquid level in the bottl~, changes ln tem-perature, changes ln the venous or arterial pre~ure of ~ :1058at67 the patlent, patlent movement, and drlft ln the effective setting o~ the roll clamp or other valve mechanism plnching the feedlng tube. Moreover~ there are a number o~ situ-ation~, such as ln intenslve care, cardiac and pediatrlc patlents, or where ~ther potent drugs are being ad~in-lstered, where the de~lred drop flow rate must be capable o~ very precise selection.
It wlll be apparent, therefore, that some of tha most crltical problems con~ronting hospltal personnel raced lO wlth an overwhelmlng duty schedule and limlted tlme avall-ablllty are the problems of quickly, easlly, reliably and accurately monltoring and regulatlng flow rates ln the parenteral administration o~ mçdical liquida.
In recent years, a number of electrlcal monltor-ing systems, drop flow controllers and ln~uslon pump3 have been developed to accomplish the varlous tasks oP senslng and regulatlng drop flow rates. However, while such moni-torlng and drop rate control devlces have ~enerally served th~lr purpo~e, they have not always proven entirely satls-~actory from the standpolnt o~ cost, complexlty, ~tabillty,reliability, accuracy, or precislon of adJustment over a wlde range of selected rlow rates. In additlon, such ~ystem~ have sometimes been subJect to drift and substan-tlal flow rate varlatlons due to changes in temperature, reedlng tube crlmpsJ varlatlons ln venous or arterlal pres- --sure of the patlent, or variatlons in the helght of the bottle or solutlon level wlthln the bottle. Substantlal dlfflcultles have also been experienced particularly in connection wlth establlshlng and malntalnlng accurate flow at very low flow rates.
PosltlYe pressure pumps of the closed-loop perlstaltic type have been provlded which overcome some o~
the aforementloned dlf~icultles wlth regard to drlft, and 1058~67 accurate flow at low flow rates. HoweverJ even such closed-loop posltlve pressure systems only serve to malntaln ac-curacy of flow in terms of stabillzlng to a preselected drop flow rate, rather than deliverlng a precl~e pre-selected volume o~ fluld, e.g.g in cubic centimeters per hour. The reason for this is that the accuracy of such a system i8 limited lnherently to the accuracy of the ~lze of the drops produced by an intravenous adminlstratlon ~et, and the actual drop~ produced by the latter apparatus can vary rather substantlally from its de~ignated drop size) e.g., due to drip chamber structural variatlons, by as much as thlrty percent.
More recently, po~ltive pressure infusion pumps of the syringe type have also been provlded, wherein a syringe having a very precise displacement volume ls re-peatedly fllled and emptied on alternate syringe plston strokes during a combined "flll" and "pump" operatlonal cycle, 90 that control o~ the rate at whlch the syringe is fllled and emptled provides an accurate means for preci~e ~luld volume dellvery over a prescrlbed perlod o~ time.
Such syrlnge pumps are essentlally independent of drop flow lnaccuracies lntroduced by I.V. admlnistratlon sets and appear to provlde the best overall solution to accur-ate and stable fluld volume dellvery over long perlods of tlme, at both high and low flow rates. However, ~lnce a portion of each operatlng ¢ycle with such eyrlnge pumps i3 concerned wlth filling the syrlnge, rather than de-llvering ~luld to the patient in a pumping mode7 there is a need for extremely preclse control over the intake and ~0 output syringe valving and the dlrectlon of rotatlon of the motor driving the syrlnge. Such valve ~ontrol must not only be very posltlve in its actlon and extremely accurate in its timing, but must also be in precl~e ~ OS8467 synchronlsm with the control over motor direction.
In addition, syringe pumps of the prior art pri-marily depend on valving embodied directly within the syrlnge ltself. This not only increases the co~t and complexlty of the syringe, partlcularly where disposable syrin~es are employed, but usually also results in reduced reliability of operatlon.
Hence, those concerned wlth the development and use of parenteral ~luld administration system s, and par-tlcularly those concerned with the design of syringe pumps, have long recognized the need for improved, rela-tlvely slmple, economlcal, reliable, stable and accurate valving and motor control systems ~or such syrlnge pumps.
The present lnvention clearly fulfills this need.
Brlefly, and in general terms, the present inven-tlon provides a new and lmproved system for accurately controlling fluld ~low in the parenteral admlnlstration of medlcal liqulds, whereln the repetitive openlng and clos-ing of a palr of lntake and output I.V tubes communicating 20 with a syringe is automatically accomplished during suc-cessive flll and pump perlods by means of Gam control of a pair o~ plvotal tube pincher~ which alternately pinch of~
and open the lntake and output tube~ in proper sequence.
In addition, the physical position o~ one of the tube plnchers is monitored and controls the dlrection o~ rota-tlon o~ the pump motor and, hence, determines the fill or pump mode of operation of the syringe. Such valving and motor dlrectlon control is accomplished with no lost motion or delay, in that the valving action and motor direction 30 changes are automatically malntained in preclse synchron-ism. Moreover, valving ls provlded without the need ~or providing relatively complex, expensive and sometimes un-rellable valve structures in the syringe ltsel~.
~058~67 More particularly, the present invention provldes a new and improved syrlnge pump embodylng a reversible~
rotary cam controlled reclprocating sllde bar for alter-nately movlng each of a pair o~ tube pinchers to succes-slvely clamp o~f and open the inta~e and output I.V tubes of the syringe to fluld flow, and, ~urther, controlllng motor dlrection ln synchronism with the sequentlal open and closed states of the I.V. tubes, to properly enable performance of successive cycle of ~ill and pump strokes.
The rotary cam includes an arcuate ridge ad~acent its outer periphery definlng semi-circular inner and outer camming ~urfaces agalnst which a cam follower ls blased, the cam follower being held against one cammlng surface during performance of a pump stroke and against the other camming sur~ace during performance o~ a ~ill stroke, the cam follower typlcally being in the form of a pin secured to and pro~ecting ~rom one side o~ a slide bar which re-ciprocates int~rmlttently back and forth in a guide block, along a linear path. Each movement o~ the sllde bar 20 colncides with a change ~rom a fill stroke J'~O a p~mp ~troke, or from a pump stroke to a fill stroke, in the overall operatlonal cycle o~ the syringe pump.
~ oth tube pinchers are pivotally mounted and spring blased towards each other and towards the tube ¢lamping state The slide bar i3 power driven by an ex-tension spring. During per~ormance of each syringe stroke, the cam surface engaglng the slide bar pin holds the sllde bar a~alnst the appropriate tube pincher to pivot the latter and hold it in the tube-open positlon, thereby relleving the slide bar spring of the task o~ overcomlng the pincher spring durlng performance of each ~yringe stroke. In addition, during the transition period between syringe strokes~ the slide bar sprlng is lnltlally -assisted ln lts movement by the pincher sprlng, the slide bar sprlng only having to work against the pincher spring in the latter portion of the sllde bar stroke when the ~lide bar has already acquired some momentum.
The slide bar center is of~set from the center of rotatlon o~ the cam, at the end of each sllde bar stroke reposltlonlng the pinchers. In this regard, one end of the slide bar spring is secured to the center o~ the slide bar, while the other end is secured to a point along the outer 10 perlphery of the rotary cam. ~herefore, as the cam rotates, with the sllde bar held statlonary (since the sllde bar pin is blased agalnst elther the inner or outer arcuate cam-ming surface), the sllde bar spring ls tensioned and sud-denly released, to shift the slide bar longltudlnally and reposltlon the tube pinchers, only when the sllde bar pln cam ~ollower comes to the end of the arcuate camming sur-- face and drops of~ to move either from the inner cammlng surface to the outer cammlng surface, or ~rom the outer sur~ace to the lnner ~urface of the cam, depending upon 20 the partlcular syrlnge stroke ~ust completed. Then the ~ cam begins to turn in the opposite directlonJ agaln trap-- plng the slide bar cam follower pin to malntain the slide - bar in a ~ixed posltion whlle stretchlng and rotatlng the sllde bar extension sprlng. When the latter spring has been fully stretched and rotated 180 to cock the slide bar mechanlsm, the other end of the arcuate ridge on the cam goes past the slide bar pin, allowing the slide bar to snap over to it~ alternate positlon and begin the entlre cycle over agaln.
A ~ixed llght source and photoelectrlc sensor arrangement provides a reference light beam whlch ls selectively interrupted by an opaque flag carried on one o~ the tube pinchers. The flag is repositloned each time -7~
, . ,. ~ . .
the tube pincher on whlch lt 13 mounted l~moved~ so that a control signal is developed indicatlve of the syrlnge stro~e about to be performed, the control slgnal being used to establlsh the proper dlrectlon o~ rotation of the motor.
The new and improved syrlnge pump valving and motor dlrectlon control system of the present invention is extremely accurate and rellable. The sy3tem provides valve control without the need for separate valves ln the syrlnge itself and provldes precise motor dlrection con-trol ln per~ect synchronlsm with the opening and closing of the syrin~e intake and output llnes.
In one aspect of this invention there is provid~
apparatus for use in a syringe pump having a housing and intake and output flexible IV tubes. The apparatus comp-risess a pair of movable tube p~chers positioned adjacent the IV tubes to normally pinch off the tubes; drive means for alternately positioned said tube pinchers to open and close said IV t~be~ in proper sequence for performance of fill and pump strokes by the syringe pumps; cam means within the housing in the vicinity of said tube pinchers; and and cam follower means consisting of a single member posi-tioned by said cam means for controlling substantially simultaneous snap action positioning of both of said tube pinchers so that said positioning maintains a one tube always open and one tube always closed relationship.
The above and other objects, aspects and ad~antages of the present invention will become.apparent from the following more detailed description, when taken in conjunc-tion with the accompanying drawings of an illustrative embodiment.
FIG~RE 1 i3 a perspectlve view showlng the ln-terior structure of ~ syrlnge pump embodying the present '. .~
, - 8 -~Q58g~67 lnventlon, the outer pump houslng belng shown ln da~hed li.nes;
FIGURE 2 is an enlarged, plan view, of the syringe pump of FIG~RE 1 with the top plate removed, and lllus_.
trates the apparatus durlng a pump stroke, sequential positions o~ the apparatus being shown in phantom;
FIG~RE 3 ls a fragmentary sectlonal vlew, taken along the line 3-3 ln FIGURE 2;
FIGURE 4 1s a fragmentary sectlonal vlew, taken along the llne 4-4 in FIaURE 2;
FIG~RE 5 ls a plan view slmllar to FIGURE 2, and illustrates the state o~ the apparatus during per-~ormance Or a fill stroke; snd FIGURE 6 is a combined elevational and sectlonal vlew, taken along the line 6-6 in FIGURE 5.
Referring now to the drawings, there ls shown a :
, .
8a -' ~ . - . .
syringe pump system for fluid flow control, embodying the features of the present invention. In the ensulng descrlp-tlon, whlle reference ls made to the term "I.V.", normally connoting lntravenous administration, it is to be understood that this is by way o~ example only, and the system of the present lnvention is suitable ~or other forms of parenteral administration as well as intravenous adminlstratlon.
The system shown in FIG~RE 1 deplcts a syringe ~;
pump embodylng a syringe 10 whlch preferably is ln the form 10 Of a dlsposable cartridge, but it will become apparent that all o~ the ~eatures of the present inventlon may be prac-ticed independently of whether or not the syringe 10 is dlsposable. The syrlnge 10 essentially lncludes a molded cylinder lOa ln whlch a piston lOb is slidably received and adapted to be reciprocated back and forth along the axis of the cylinder by an integral piston rod lOc which is re-mDvably mounted at one end in a coupling shoe 11 carried by a lead screw 12 which is advanced and retracted by a suit-able drive system. The drive system includes a reversible, 20 d.c. stepping motor 13 and appropriate gearing 14, to drive the lead screw 12 whlch is, in turn, coupled to the piston ~d lOc of the syrlnge 10. The motor 13 ls energlzed by a pulse train of motor drive pulses generated by an appro-priate electrical control system 15.
; The syringe 10 includes an inlet port lOd and an outlet port lOe. The inlet port lOd communicate~ through a sultable lntake I.V. tube 16 wlth any appropriate liquid source (not shown), usually an I.V. bottle contalning appro-priate drugs and/or nutrients in fluid form. Typlcally, 30 the lntake I.V. tube 16 is part of an I.V. adminstratlon set which lncludes a transparent drip chamber ln the line be-tween the syringe 10 and the liquld source.
A similar output I.V tube 17 ls connected at _g_ ., one end to the outlet port lOe of the syrlnge 10 and conveys fluid ~rom the syrlnge to a patient.
A pair of syrlnge pump valves 18, 19, exte mal to the syringe 10, are o~ the tube pincher typeJ and are selec-tlvely opened and closed at appropriate times in the overall pumping cycle~ under the control of a suitable valve control system 20. The valve 18 controls the inlet port lOd and iB
cpen during the fill stroke to enable fluid to be drawn from the liquid æource, through the intake line 16, into the syrlnge 10, the valve 18 belng closed during the pump stroke to prevent fluld ~rom exltlng the syringe through the lnlet port. The valve 19 controls the outlet port lOe and i5 ` open during the pump stroke to enable fluid dellvery from the ~yrlnge 10 to the patient through the output line 17, the valve 19 being closed ~uring the fill stroke.
The valve control system 20 ls also drivenJ through the gearing 14, by the same drive motor 13 as is used to operate the syrlnge 10. The valve control system 20 also provides lnformation to the electrical control ~ystem 15 controlling the motor 13, lndicating that the syrlnge 10 is elther in the fill stroke or the pump ~troke, and this informatlon, in turn, enables the electrical control system ko establish the proper direction of rotation of the motor.
The electrical control system 15 may be of conventional design for electrioally energlzlng the motor 13 and con-trolling its direction of rotation.
The motor 13 drives, through the gearing 14 and an output camshaft 21, a reversible~ semi-circular rotary cam 22 whlch controls the opened and closed positions of the 30 syrlnge pump valves 18, 19.
~ he gear ratio of the gearing 14 ls speclflcally selected so that the rotary cam 22 rotates through an angle of approximately 180 during a pump stroke of the syringe --10-- `
105~67 10, and then reverses and rotates through another 1&0 ln the opposite direction durlng an intake stroke. Hence, the rotary cam 22 is essentially a half-turn cam. The camsha~t 21 rotates the cam 22 which biases a slide bar 23 to alter-nately hold one syringe pump valve open and then the other, ; in proper cyclical sequence.
; The ~yrlnge pump valves 18, 19 conslst of a palr of pivotal tube pinchers 24, 25 which alternatively pinch of~ and open the intake and output tubes 16J 17 respectlvely, 10 0~ the syringe 10. The tube p~nchers 24, 25 are spring biased to the tube shut-off position and are positlvely driven open by the valve control system 20, thus allowlng ~11 tube closure regardless of normal variations in I.V.
tubing dlameter and wall thickness.
As best observed in FIGS. 2-5, each of the tube r pinchers 24, 25, is o~ substantially L-shape and includes a long arm 24a, 25a, respectively, and a Rhort arm 24b, 25b, , respectively. One face o~ the short arm 24b is shaped to deflne a pincher blade 24c adapted to cooperate wlth the 20 confronting face o~ a shoulder 26 defined on the interior slde o~ a syrlnge pump access door 27 to the ~yringe com-partment. Slmllarly, a plncher blade 25c 18 de~lned by the short arm 25b of the output tube pincher 25. Together, the plncher blades 24c, 25c and the access door shoulder 26 de~ine a pair of clamping surfa¢es between which the lntake and output I.V tubes 16, 17 pass. The access door 27 is held shut, after the syringe has been installed, by any suitable latch 27a.
The lntake tube pincher 24, is plvotally mounted 30 by means o~ a pivot pln and bushing at 28. SimllarlyJ the .
output pincher is pivotally mounted at 29. ~oth tube pinchers are spring-blased to the tube clamping shut-off ~tate by a coil sprlng 30 extending between the pinchers ,, and approprlately secured at each end to one Or the plnchers, as by anchor pins 24d, 25d, respectively.
The syrlnge pump valves 18, 19 are selectlvely opened ln proper cyclical sequence by plvoting the tube pinchers 24, 25J one at a tlme, vla contact with the re-ciprocating, intermittent motlon sllde bar 23 which i8 power driven by a slide bar extension spring 32. The ~llde bar 23 is slldably mounted within a guide block 31 and contacts the tube pinchers 24~ 25 by bumper pads 33 mounted at each 10 end of the slide bar. In order for the slide bar spring 32 -to drlve the slide bar 23 in both dlrections, one end of the ~lide bar sprlng ls secured to the slide bar at its center, by an anchor pin 32a, whlle the other end of the slide bar spring is secured to the rotary cam 22 near its outer perlphery by an anchor pln 32b. In either of its two positions at the end of a slide bar stroke, the center of the slide bar 23 along its longitudlnal axis is offset from the center of rotation of the cam 22.
The slide bar 23 moves only upon completion of a 20 syringe stroke; either a fill stroke or a pump stroke. The slide bar 23 ls maintained in a fixed position during per-formance of any syringe stroke by an arcuate, seml-circular ridge 22a on the cam 22 defining inner and outer cammlng surfaces 22b~ 22c, respectlvely, ad~acent the outer per-lphery of the cam, each of these cammlng surfaces alter-nately abuttlng a sllde bar pin 23a secured to and project-ing from one face of the slide bar at the end of the slide bar.
The sllde bar pln 23a is a cam follower which is 30 held against one of the camming surfaces 22b, 22c durlng performance of each syringe stroke and swltches positlons from one of these cammlng surfaces to the other camming surface at the end of each stroke. As the cam 22 rotates, the slide bar spring 32 is tensloned to cock the slide bar mechanlsm. Since the center o~ the slide bar 23 does not coinclde wlth the center of the cam 22 in elther of the two positions of the slide bar, rotation of the cam causes the slide bar spring 32 to stretch because the slide bar center is always repositioned to the opposlte side of the cam center when the cam rotates through a 180 cycle.
Hence, the slide bar spring 32 is tensioned by turning the cam 22 and yet the cam holds the slide bar 23 in the same position throughout the 180 rotary cycle.
As best observed ln FIGS. 2 and 5, wherein mid-cycle positions of the rotary cam 22 are shown ln phantomg when the end of the ridge 22a on the cam 22 ls rotated past the slide bar pin 23a, the slide bar spring 32 snaps the slide bar 23 over from one of its two positions to the other position ln performance of a slide bar stroke) causing the tube pinchers 24, 25 to change positlon. The tube pincher that was previously open, now closes, while the tube pin-cher that was prev~ously closed now opens. Then the cam 22 begins to turn in the reverse direction, agaln ~rapping the slide bar pin 23a against one of the camming surfaces 22b, 22c, to maintain the sllde bar 23 in a fixed position while tensioning and rotating the slide bar spring 32. When the slide bar spring 32 has been fully tensioned and rotated 180, again cocking the sllde bar mechani~m, the other end of the semi-circular ridge 22a on the cam 22 goes past the sllde bar pin 23a, allowing the slide bar 23 to briskly snap over to its alternate position and begln the entire syringe pump cycle agaln. The result is extremely precise, positive action valving.
In the embodiment of the invention illustrated, the slide bar pin 23a rides on the outer surface 22c of the cam 22 during the pump stroke (FIG. 2) and rides on the ``` tOS8467 lnner surface 22b of the cam during the fill stroke (FIG.5).
As the sllde bar 23 moves from one posltlon to the other, it pushes one or the other of the tube plncher~ 24, 25 open.
The tube plncher spring 30 is what actually provldes the tube closure force, l.e., the force necessary to close on the I.V tubes 16, 17. The sllde bar extension ~pring 32 merely provldes a ~orce to drive the slide bar 23 th~ ugh a slide bar stroke.
One advantage of the valve control system 20 re-10 sides in the manner in which the tube pincher sprlng 30 always holds one of the tube pinchers 24, 25 against the I.V. tubing. As a result, the sllde bar spring 32 can move the sllde bar 23 and both tube plnchers 24, 25 without hav-lng to overcome the tube pincher spring 30 durlng the entire slide bar stroke. The tube pincher sprlng 30 is stretched between the palr o~ tube pinchers 24J 25 and, if the I.V. tubing were not present, it would cause both tube plnchers to rest against both o~ the bumper pads 31 of the slide bar 23. However, when the I.V tubing is in place, 20 it cau~es the closed tube plncher to be spaced a small dis-tance away ~rom the end of the slide bar 23, as at 34 in FIG. 2 and at 35 ln FIG. 5. Because of thls gap, when the sllde bar 23 first starts tomove at the end of a syrlnge ~ill or pump stroke~ the tube pincher sprlng 30 aotually aids the slide bar sprlng 32 ln initially drlvlng the 9 llde bar. Only near the end of the slide bar stroke, when the slide bar 23 has already bu~lt up considerable momentum, does the tube pincher spring 30 exert any force tending to retard the motion of the slide bar.
The position of the tube pinchers 24, 25 is sensed by a comblned light ~ource and photoelectric sensor assem-bly 37, which controls the dlrection of rotation of the motor 13. In this regard, the pincher position sensor ~058467 assembly 37 ls mounted on the underside of the cover plate ~3 (FIG. 6) of the pump houslng and ls thereby supported ln a flxed positlon. An opaque flag 39 i8 carrled by the output tube plncher 25.
As shown in FIGURE 2, when the flag 39 interrupts the reference llght beam between the light source and photo-electric sensor, an electrical signal is generated indica-tlng that the system ls elther about to initiate or ls al-ready performing a pump stroke, i.e., the output tube 17 ls 10 cpen. In contrast, as observed in FIGIJRE 5, when the flag 39 is retracted by the tube pincher 25, an electrical signal ls generated indicatlng that the system i~ either about to initiate or i~ in the performance of a fill stroke, i.e., the intake tubing 16 is open. The motor dlrection control afforded by such an arrangement i~ in precise synchronism with the intake and output tube valving and the pump can never cause fluid to be taken in through the syrlnge output tube 17, or be pumped through the syringe intake tube 16.
Moreover, the motor 13 never reverses until the tube 20 pinchers 24, 25 have been actuated. This results ln a very preclse volume displacement for each syringe stroke.
In summary, when the sllde bar pin 23a arrives at the end of the inner camming surface 22b at the completion of a fill strokeJ the slide bar pin will drop off the cam 22 because of the force exerted by the tensioned sllde bar spring 32, and the pin will then move to the outer camming surface 22c for performance of a pump stroke (FIG. 2).
This will reposition the tube plnchers 24, 25 to close the intake tube 16, open the output tube 17, and generate a 30 control signal via the position sensor 37 to reverse the motor 13. Then the cam 22 will reverse, because the motor 13 is reversed, and the cam will rotate while capturing the slide bar pln 23a on its outer cammlng surface 23c. The cam 22 wlll go through another 180 cycle in the reverse direction while again stretching the slide bar spring 32~
thls time because the slide bar center is on the other slde of the cam center. At the end of the 130 cycle, the sllde bar pin 23a will agaln drop of~ the outer cammlng surface 22c, and move to the inner camming surface 22b where it started ~FIG. 5). In thls way, the slide bar 23 oscillates intermittently between its two extreme posltlons to plvot the tube pinchers 24, 25 and open and close the intake and 10 output I.V. tubes 16, 17, precisely and positlvely at appro-priate times in the operational cycle of the syringe pump.
The syringe pump valving and motor direction con-trol ~ystem of the present invention satis~ies a long exlstlng need ~or improved, relatively slmple~ economical, reliable, stable and accurate valving and motor control systems for such syringe pumps. The system provides extremely precise valve control without the need for separ-ate valves in the syringe itself and provides precise motor direction control in perfect synchronism with the opening 20 and closing o~ the syringe intake and output tubes.
It will be apparent ~rom the foregoing that, while particular forms of the invention have been lllustrated and described, various modification~ can be made without departing from the spirit and scope of the invention.
Accordingly, lt is not lntended that the invention be llmited, except as by the appended claims.
; .
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in syringe pumps and, more partlcularly, to a new and lm-proved valve control sy~tem for such pump~ whlch reliably and preci~ely opens and clo~es the intake and output I.V.
tubes for a syrlnge at approprlate polnts ln the pumping cycle and also generates a control slgnal for ~stabll~hlng dire¢tion of motor rotatlon.
The usual medical procedure for the gradual par-enteral adm$nist~ation o~ liquid~ lnto the human body, ~u~h a~ llquid nutrlent~, blood or plasma, make~ use of appara-tu3 whlch 1~ commonly re~erred to in the medlcal arts as an intravenou~ admlnlstratlon ~et. The lntravenou~ set usu-ally comprlses a bottle Or li~uid, normally supported ln ; an lnverted position, an intravenou~ ~eeding tube, typi-cally Or alear pla3tlc, and a sultable valve mechanlsm, such as a roll clamp, which allow~ the liquid to drlp out Or th~ bottle at a selectlvely ad~ustable rate into a tran3parent drip chamber below the bottle. ~he drlp cham-ber serve~ the dual runctlon Or allowln~ a nurse or other 20 attendant to ob3erve the rate at which the llquld drip~ out Or the bottle, and al~o creates a reservoir ror the liquld at the lower end Or the drlp chamber to in~ure th~t no alr enters the main reeding tube leading to the patlent.
Whlle ob~ervation o~ the rate of drop rlow via the drip chamber 18 a simple way of controlllng the amount o~ liquid fed to a patient over a perlod o~ time, its ultl-mate ef~ectiveness requlre~ that a relatively constant vlgil be maintalned on the drop flo~, le~t it cea~e en-tlrely due to exhau~tion o~ the liquid supplied or b~come 30 a continuous stream and perhaps increa~e the rate of liquld introductlon to the patlent to dangerou~ levels.
~ y way Or example, lt ha~ been the general prac-tlce ln hospltals to have nur~e3 periodlcally monltor drop ~OS8467 flow rate ~t each intravenous feedlng or parenteral ln-fusion ~tation. Such monitorlng of drop flow 18 a tedlous, and tlme consumlng process, prone to error and assoclated, po~lbly serlous consequence~, and resultlng ln a substan-tial reduction o~ the avallable tlme o~ quall~ied medical personnel ~or other lmportant dutle~. Typl¢ally, the nurse monitorlng drop ~low rate will use a watoh to tlme the number of drops ~lowlng in an interval of one or more minutes, and she will then mentally perform the mathe-matics necessary to convert the ob~erved data to an appro-priate fluld flow rate, e.g., in drops per mlnute. If the calculated ~low rate i8 sub~tantlally different than the prescribed rateJ the nur~e must manually ad~ust the roll clamp ~or a new rate, count drop~ again, and re¢alcu-late to measure the new flow rate.
Obvlou~ly, each of the aforedescribed mea~urements, calculatlons and flow rate ad~ustments usually take sever-al minute~ tlme whlch, when multlplled by the number of statlons belng monltored and the number of tlmes eaoh ~-station ~hould be monltored per day, ¢an re~ult ln a sub-stantlal percentage of total personnel time available. In addition, under the pressure of a heavy ~chedule, the ob-~ervations and calculatlons performed by a harrled nurse in measurlng and ad~usting flow rate may not always prove to be reliable and, hence, errors do oocur re~ulting in undeslred, possibly dangerous lnfu~lon flow rates.
In addition to the aforedescrlbed dl~flcultles, the parenteral admlnl~tratlon of medical liquids by gravity - lnduced hydrostatic pres~ure lnfu~ion o~ the llquid from a ; 30 bottle or other container suspended above the patient, 1 very susceptible to fluid flow rate variation due to changes ln the liquid level in the bottl~, changes ln tem-perature, changes ln the venous or arterial pre~ure of ~ :1058at67 the patlent, patlent movement, and drlft ln the effective setting o~ the roll clamp or other valve mechanism plnching the feedlng tube. Moreover~ there are a number o~ situ-ation~, such as ln intenslve care, cardiac and pediatrlc patlents, or where ~ther potent drugs are being ad~in-lstered, where the de~lred drop flow rate must be capable o~ very precise selection.
It wlll be apparent, therefore, that some of tha most crltical problems con~ronting hospltal personnel raced lO wlth an overwhelmlng duty schedule and limlted tlme avall-ablllty are the problems of quickly, easlly, reliably and accurately monltoring and regulatlng flow rates ln the parenteral administration o~ mçdical liquida.
In recent years, a number of electrlcal monltor-ing systems, drop flow controllers and ln~uslon pump3 have been developed to accomplish the varlous tasks oP senslng and regulatlng drop flow rates. However, while such moni-torlng and drop rate control devlces have ~enerally served th~lr purpo~e, they have not always proven entirely satls-~actory from the standpolnt o~ cost, complexlty, ~tabillty,reliability, accuracy, or precislon of adJustment over a wlde range of selected rlow rates. In additlon, such ~ystem~ have sometimes been subJect to drift and substan-tlal flow rate varlatlons due to changes in temperature, reedlng tube crlmpsJ varlatlons ln venous or arterlal pres- --sure of the patlent, or variatlons in the helght of the bottle or solutlon level wlthln the bottle. Substantlal dlfflcultles have also been experienced particularly in connection wlth establlshlng and malntalnlng accurate flow at very low flow rates.
PosltlYe pressure pumps of the closed-loop perlstaltic type have been provlded which overcome some o~
the aforementloned dlf~icultles wlth regard to drlft, and 1058~67 accurate flow at low flow rates. HoweverJ even such closed-loop posltlve pressure systems only serve to malntaln ac-curacy of flow in terms of stabillzlng to a preselected drop flow rate, rather than deliverlng a precl~e pre-selected volume o~ fluld, e.g.g in cubic centimeters per hour. The reason for this is that the accuracy of such a system i8 limited lnherently to the accuracy of the ~lze of the drops produced by an intravenous adminlstratlon ~et, and the actual drop~ produced by the latter apparatus can vary rather substantlally from its de~ignated drop size) e.g., due to drip chamber structural variatlons, by as much as thlrty percent.
More recently, po~ltive pressure infusion pumps of the syringe type have also been provlded, wherein a syringe having a very precise displacement volume ls re-peatedly fllled and emptied on alternate syringe plston strokes during a combined "flll" and "pump" operatlonal cycle, 90 that control o~ the rate at whlch the syringe is fllled and emptled provides an accurate means for preci~e ~luld volume dellvery over a prescrlbed perlod o~ time.
Such syrlnge pumps are essentlally independent of drop flow lnaccuracies lntroduced by I.V. admlnistratlon sets and appear to provlde the best overall solution to accur-ate and stable fluld volume dellvery over long perlods of tlme, at both high and low flow rates. However, ~lnce a portion of each operatlng ¢ycle with such eyrlnge pumps i3 concerned wlth filling the syrlnge, rather than de-llvering ~luld to the patient in a pumping mode7 there is a need for extremely preclse control over the intake and ~0 output syringe valving and the dlrectlon of rotatlon of the motor driving the syrlnge. Such valve ~ontrol must not only be very posltlve in its actlon and extremely accurate in its timing, but must also be in precl~e ~ OS8467 synchronlsm with the control over motor direction.
In addition, syringe pumps of the prior art pri-marily depend on valving embodied directly within the syrlnge ltself. This not only increases the co~t and complexlty of the syringe, partlcularly where disposable syrin~es are employed, but usually also results in reduced reliability of operatlon.
Hence, those concerned wlth the development and use of parenteral ~luld administration system s, and par-tlcularly those concerned with the design of syringe pumps, have long recognized the need for improved, rela-tlvely slmple, economlcal, reliable, stable and accurate valving and motor control systems ~or such syrlnge pumps.
The present lnvention clearly fulfills this need.
Brlefly, and in general terms, the present inven-tlon provides a new and lmproved system for accurately controlling fluld ~low in the parenteral admlnlstration of medlcal liqulds, whereln the repetitive openlng and clos-ing of a palr of lntake and output I.V tubes communicating 20 with a syringe is automatically accomplished during suc-cessive flll and pump perlods by means of Gam control of a pair o~ plvotal tube pincher~ which alternately pinch of~
and open the lntake and output tube~ in proper sequence.
In addition, the physical position o~ one of the tube plnchers is monitored and controls the dlrection o~ rota-tlon o~ the pump motor and, hence, determines the fill or pump mode of operation of the syringe. Such valving and motor dlrectlon control is accomplished with no lost motion or delay, in that the valving action and motor direction 30 changes are automatically malntained in preclse synchron-ism. Moreover, valving ls provlded without the need ~or providing relatively complex, expensive and sometimes un-rellable valve structures in the syringe ltsel~.
~058~67 More particularly, the present invention provldes a new and improved syrlnge pump embodylng a reversible~
rotary cam controlled reclprocating sllde bar for alter-nately movlng each of a pair o~ tube pinchers to succes-slvely clamp o~f and open the inta~e and output I.V tubes of the syringe to fluld flow, and, ~urther, controlllng motor dlrection ln synchronism with the sequentlal open and closed states of the I.V. tubes, to properly enable performance of successive cycle of ~ill and pump strokes.
The rotary cam includes an arcuate ridge ad~acent its outer periphery definlng semi-circular inner and outer camming ~urfaces agalnst which a cam follower ls blased, the cam follower being held against one cammlng surface during performance of a pump stroke and against the other camming sur~ace during performance o~ a ~ill stroke, the cam follower typlcally being in the form of a pin secured to and pro~ecting ~rom one side o~ a slide bar which re-ciprocates int~rmlttently back and forth in a guide block, along a linear path. Each movement o~ the sllde bar 20 colncides with a change ~rom a fill stroke J'~O a p~mp ~troke, or from a pump stroke to a fill stroke, in the overall operatlonal cycle o~ the syringe pump.
~ oth tube pinchers are pivotally mounted and spring blased towards each other and towards the tube ¢lamping state The slide bar i3 power driven by an ex-tension spring. During per~ormance of each syringe stroke, the cam surface engaglng the slide bar pin holds the sllde bar a~alnst the appropriate tube pincher to pivot the latter and hold it in the tube-open positlon, thereby relleving the slide bar spring of the task o~ overcomlng the pincher spring durlng performance of each ~yringe stroke. In addition, during the transition period between syringe strokes~ the slide bar sprlng is lnltlally -assisted ln lts movement by the pincher sprlng, the slide bar sprlng only having to work against the pincher spring in the latter portion of the sllde bar stroke when the ~lide bar has already acquired some momentum.
The slide bar center is of~set from the center of rotatlon o~ the cam, at the end of each sllde bar stroke reposltlonlng the pinchers. In this regard, one end of the slide bar spring is secured to the center o~ the slide bar, while the other end is secured to a point along the outer 10 perlphery of the rotary cam. ~herefore, as the cam rotates, with the sllde bar held statlonary (since the sllde bar pin is blased agalnst elther the inner or outer arcuate cam-ming surface), the sllde bar spring ls tensioned and sud-denly released, to shift the slide bar longltudlnally and reposltlon the tube pinchers, only when the sllde bar pln cam ~ollower comes to the end of the arcuate camming sur-- face and drops of~ to move either from the inner cammlng surface to the outer cammlng surface, or ~rom the outer sur~ace to the lnner ~urface of the cam, depending upon 20 the partlcular syrlnge stroke ~ust completed. Then the ~ cam begins to turn in the opposite directlonJ agaln trap-- plng the slide bar cam follower pin to malntain the slide - bar in a ~ixed posltion whlle stretchlng and rotatlng the sllde bar extension sprlng. When the latter spring has been fully stretched and rotated 180 to cock the slide bar mechanlsm, the other end of the arcuate ridge on the cam goes past the slide bar pin, allowing the slide bar to snap over to it~ alternate positlon and begin the entlre cycle over agaln.
A ~ixed llght source and photoelectrlc sensor arrangement provides a reference light beam whlch ls selectively interrupted by an opaque flag carried on one o~ the tube pinchers. The flag is repositloned each time -7~
, . ,. ~ . .
the tube pincher on whlch lt 13 mounted l~moved~ so that a control signal is developed indicatlve of the syrlnge stro~e about to be performed, the control slgnal being used to establlsh the proper dlrectlon o~ rotation of the motor.
The new and improved syrlnge pump valving and motor dlrectlon control system of the present invention is extremely accurate and rellable. The sy3tem provides valve control without the need for separate valves ln the syrlnge itself and provldes precise motor dlrection con-trol ln per~ect synchronlsm with the opening and closing of the syrin~e intake and output llnes.
In one aspect of this invention there is provid~
apparatus for use in a syringe pump having a housing and intake and output flexible IV tubes. The apparatus comp-risess a pair of movable tube p~chers positioned adjacent the IV tubes to normally pinch off the tubes; drive means for alternately positioned said tube pinchers to open and close said IV t~be~ in proper sequence for performance of fill and pump strokes by the syringe pumps; cam means within the housing in the vicinity of said tube pinchers; and and cam follower means consisting of a single member posi-tioned by said cam means for controlling substantially simultaneous snap action positioning of both of said tube pinchers so that said positioning maintains a one tube always open and one tube always closed relationship.
The above and other objects, aspects and ad~antages of the present invention will become.apparent from the following more detailed description, when taken in conjunc-tion with the accompanying drawings of an illustrative embodiment.
FIG~RE 1 i3 a perspectlve view showlng the ln-terior structure of ~ syrlnge pump embodying the present '. .~
, - 8 -~Q58g~67 lnventlon, the outer pump houslng belng shown ln da~hed li.nes;
FIGURE 2 is an enlarged, plan view, of the syringe pump of FIG~RE 1 with the top plate removed, and lllus_.
trates the apparatus durlng a pump stroke, sequential positions o~ the apparatus being shown in phantom;
FIG~RE 3 ls a fragmentary sectlonal vlew, taken along the line 3-3 ln FIGURE 2;
FIGURE 4 1s a fragmentary sectlonal vlew, taken along the llne 4-4 in FIaURE 2;
FIG~RE 5 ls a plan view slmllar to FIGURE 2, and illustrates the state o~ the apparatus during per-~ormance Or a fill stroke; snd FIGURE 6 is a combined elevational and sectlonal vlew, taken along the line 6-6 in FIGURE 5.
Referring now to the drawings, there ls shown a :
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8a -' ~ . - . .
syringe pump system for fluid flow control, embodying the features of the present invention. In the ensulng descrlp-tlon, whlle reference ls made to the term "I.V.", normally connoting lntravenous administration, it is to be understood that this is by way o~ example only, and the system of the present lnvention is suitable ~or other forms of parenteral administration as well as intravenous adminlstratlon.
The system shown in FIG~RE 1 deplcts a syringe ~;
pump embodylng a syringe 10 whlch preferably is ln the form 10 Of a dlsposable cartridge, but it will become apparent that all o~ the ~eatures of the present inventlon may be prac-ticed independently of whether or not the syringe 10 is dlsposable. The syrlnge 10 essentially lncludes a molded cylinder lOa ln whlch a piston lOb is slidably received and adapted to be reciprocated back and forth along the axis of the cylinder by an integral piston rod lOc which is re-mDvably mounted at one end in a coupling shoe 11 carried by a lead screw 12 which is advanced and retracted by a suit-able drive system. The drive system includes a reversible, 20 d.c. stepping motor 13 and appropriate gearing 14, to drive the lead screw 12 whlch is, in turn, coupled to the piston ~d lOc of the syrlnge 10. The motor 13 ls energlzed by a pulse train of motor drive pulses generated by an appro-priate electrical control system 15.
; The syringe 10 includes an inlet port lOd and an outlet port lOe. The inlet port lOd communicate~ through a sultable lntake I.V. tube 16 wlth any appropriate liquid source (not shown), usually an I.V. bottle contalning appro-priate drugs and/or nutrients in fluid form. Typlcally, 30 the lntake I.V. tube 16 is part of an I.V. adminstratlon set which lncludes a transparent drip chamber ln the line be-tween the syringe 10 and the liquld source.
A similar output I.V tube 17 ls connected at _g_ ., one end to the outlet port lOe of the syrlnge 10 and conveys fluid ~rom the syrlnge to a patient.
A pair of syrlnge pump valves 18, 19, exte mal to the syringe 10, are o~ the tube pincher typeJ and are selec-tlvely opened and closed at appropriate times in the overall pumping cycle~ under the control of a suitable valve control system 20. The valve 18 controls the inlet port lOd and iB
cpen during the fill stroke to enable fluid to be drawn from the liquid æource, through the intake line 16, into the syrlnge 10, the valve 18 belng closed during the pump stroke to prevent fluld ~rom exltlng the syringe through the lnlet port. The valve 19 controls the outlet port lOe and i5 ` open during the pump stroke to enable fluid dellvery from the ~yrlnge 10 to the patient through the output line 17, the valve 19 being closed ~uring the fill stroke.
The valve control system 20 ls also drivenJ through the gearing 14, by the same drive motor 13 as is used to operate the syrlnge 10. The valve control system 20 also provides lnformation to the electrical control ~ystem 15 controlling the motor 13, lndicating that the syrlnge 10 is elther in the fill stroke or the pump ~troke, and this informatlon, in turn, enables the electrical control system ko establish the proper direction of rotation of the motor.
The electrical control system 15 may be of conventional design for electrioally energlzlng the motor 13 and con-trolling its direction of rotation.
The motor 13 drives, through the gearing 14 and an output camshaft 21, a reversible~ semi-circular rotary cam 22 whlch controls the opened and closed positions of the 30 syrlnge pump valves 18, 19.
~ he gear ratio of the gearing 14 ls speclflcally selected so that the rotary cam 22 rotates through an angle of approximately 180 during a pump stroke of the syringe --10-- `
105~67 10, and then reverses and rotates through another 1&0 ln the opposite direction durlng an intake stroke. Hence, the rotary cam 22 is essentially a half-turn cam. The camsha~t 21 rotates the cam 22 which biases a slide bar 23 to alter-nately hold one syringe pump valve open and then the other, ; in proper cyclical sequence.
; The ~yrlnge pump valves 18, 19 conslst of a palr of pivotal tube pinchers 24, 25 which alternatively pinch of~ and open the intake and output tubes 16J 17 respectlvely, 10 0~ the syringe 10. The tube p~nchers 24, 25 are spring biased to the tube shut-off position and are positlvely driven open by the valve control system 20, thus allowlng ~11 tube closure regardless of normal variations in I.V.
tubing dlameter and wall thickness.
As best observed in FIGS. 2-5, each of the tube r pinchers 24, 25, is o~ substantially L-shape and includes a long arm 24a, 25a, respectively, and a Rhort arm 24b, 25b, , respectively. One face o~ the short arm 24b is shaped to deflne a pincher blade 24c adapted to cooperate wlth the 20 confronting face o~ a shoulder 26 defined on the interior slde o~ a syrlnge pump access door 27 to the ~yringe com-partment. Slmllarly, a plncher blade 25c 18 de~lned by the short arm 25b of the output tube pincher 25. Together, the plncher blades 24c, 25c and the access door shoulder 26 de~ine a pair of clamping surfa¢es between which the lntake and output I.V tubes 16, 17 pass. The access door 27 is held shut, after the syringe has been installed, by any suitable latch 27a.
The lntake tube pincher 24, is plvotally mounted 30 by means o~ a pivot pln and bushing at 28. SimllarlyJ the .
output pincher is pivotally mounted at 29. ~oth tube pinchers are spring-blased to the tube clamping shut-off ~tate by a coil sprlng 30 extending between the pinchers ,, and approprlately secured at each end to one Or the plnchers, as by anchor pins 24d, 25d, respectively.
The syrlnge pump valves 18, 19 are selectlvely opened ln proper cyclical sequence by plvoting the tube pinchers 24, 25J one at a tlme, vla contact with the re-ciprocating, intermittent motlon sllde bar 23 which i8 power driven by a slide bar extension spring 32. The ~llde bar 23 is slldably mounted within a guide block 31 and contacts the tube pinchers 24~ 25 by bumper pads 33 mounted at each 10 end of the slide bar. In order for the slide bar spring 32 -to drlve the slide bar 23 in both dlrections, one end of the ~lide bar sprlng ls secured to the slide bar at its center, by an anchor pin 32a, whlle the other end of the slide bar spring is secured to the rotary cam 22 near its outer perlphery by an anchor pln 32b. In either of its two positions at the end of a slide bar stroke, the center of the slide bar 23 along its longitudlnal axis is offset from the center of rotation of the cam 22.
The slide bar 23 moves only upon completion of a 20 syringe stroke; either a fill stroke or a pump stroke. The slide bar 23 ls maintained in a fixed position during per-formance of any syringe stroke by an arcuate, seml-circular ridge 22a on the cam 22 defining inner and outer cammlng surfaces 22b~ 22c, respectlvely, ad~acent the outer per-lphery of the cam, each of these cammlng surfaces alter-nately abuttlng a sllde bar pin 23a secured to and project-ing from one face of the slide bar at the end of the slide bar.
The sllde bar pln 23a is a cam follower which is 30 held against one of the camming surfaces 22b, 22c durlng performance of each syringe stroke and swltches positlons from one of these cammlng surfaces to the other camming surface at the end of each stroke. As the cam 22 rotates, the slide bar spring 32 is tensloned to cock the slide bar mechanlsm. Since the center o~ the slide bar 23 does not coinclde wlth the center of the cam 22 in elther of the two positions of the slide bar, rotation of the cam causes the slide bar spring 32 to stretch because the slide bar center is always repositioned to the opposlte side of the cam center when the cam rotates through a 180 cycle.
Hence, the slide bar spring 32 is tensioned by turning the cam 22 and yet the cam holds the slide bar 23 in the same position throughout the 180 rotary cycle.
As best observed ln FIGS. 2 and 5, wherein mid-cycle positions of the rotary cam 22 are shown ln phantomg when the end of the ridge 22a on the cam 22 ls rotated past the slide bar pin 23a, the slide bar spring 32 snaps the slide bar 23 over from one of its two positions to the other position ln performance of a slide bar stroke) causing the tube pinchers 24, 25 to change positlon. The tube pincher that was previously open, now closes, while the tube pin-cher that was prev~ously closed now opens. Then the cam 22 begins to turn in the reverse direction, agaln ~rapping the slide bar pin 23a against one of the camming surfaces 22b, 22c, to maintain the sllde bar 23 in a fixed position while tensioning and rotating the slide bar spring 32. When the slide bar spring 32 has been fully tensioned and rotated 180, again cocking the sllde bar mechani~m, the other end of the semi-circular ridge 22a on the cam 22 goes past the sllde bar pin 23a, allowing the slide bar 23 to briskly snap over to its alternate position and begln the entire syringe pump cycle agaln. The result is extremely precise, positive action valving.
In the embodiment of the invention illustrated, the slide bar pin 23a rides on the outer surface 22c of the cam 22 during the pump stroke (FIG. 2) and rides on the ``` tOS8467 lnner surface 22b of the cam during the fill stroke (FIG.5).
As the sllde bar 23 moves from one posltlon to the other, it pushes one or the other of the tube plncher~ 24, 25 open.
The tube plncher spring 30 is what actually provldes the tube closure force, l.e., the force necessary to close on the I.V tubes 16, 17. The sllde bar extension ~pring 32 merely provldes a ~orce to drive the slide bar 23 th~ ugh a slide bar stroke.
One advantage of the valve control system 20 re-10 sides in the manner in which the tube pincher sprlng 30 always holds one of the tube pinchers 24, 25 against the I.V. tubing. As a result, the sllde bar spring 32 can move the sllde bar 23 and both tube plnchers 24, 25 without hav-lng to overcome the tube pincher spring 30 durlng the entire slide bar stroke. The tube pincher sprlng 30 is stretched between the palr o~ tube pinchers 24J 25 and, if the I.V. tubing were not present, it would cause both tube plnchers to rest against both o~ the bumper pads 31 of the slide bar 23. However, when the I.V tubing is in place, 20 it cau~es the closed tube plncher to be spaced a small dis-tance away ~rom the end of the slide bar 23, as at 34 in FIG. 2 and at 35 ln FIG. 5. Because of thls gap, when the sllde bar 23 first starts tomove at the end of a syrlnge ~ill or pump stroke~ the tube pincher sprlng 30 aotually aids the slide bar sprlng 32 ln initially drlvlng the 9 llde bar. Only near the end of the slide bar stroke, when the slide bar 23 has already bu~lt up considerable momentum, does the tube pincher spring 30 exert any force tending to retard the motion of the slide bar.
The position of the tube pinchers 24, 25 is sensed by a comblned light ~ource and photoelectric sensor assem-bly 37, which controls the dlrection of rotation of the motor 13. In this regard, the pincher position sensor ~058467 assembly 37 ls mounted on the underside of the cover plate ~3 (FIG. 6) of the pump houslng and ls thereby supported ln a flxed positlon. An opaque flag 39 i8 carrled by the output tube plncher 25.
As shown in FIGURE 2, when the flag 39 interrupts the reference llght beam between the light source and photo-electric sensor, an electrical signal is generated indica-tlng that the system ls elther about to initiate or ls al-ready performing a pump stroke, i.e., the output tube 17 ls 10 cpen. In contrast, as observed in FIGIJRE 5, when the flag 39 is retracted by the tube pincher 25, an electrical signal ls generated indicatlng that the system i~ either about to initiate or i~ in the performance of a fill stroke, i.e., the intake tubing 16 is open. The motor dlrection control afforded by such an arrangement i~ in precise synchronism with the intake and output tube valving and the pump can never cause fluid to be taken in through the syrlnge output tube 17, or be pumped through the syringe intake tube 16.
Moreover, the motor 13 never reverses until the tube 20 pinchers 24, 25 have been actuated. This results ln a very preclse volume displacement for each syringe stroke.
In summary, when the sllde bar pin 23a arrives at the end of the inner camming surface 22b at the completion of a fill strokeJ the slide bar pin will drop off the cam 22 because of the force exerted by the tensioned sllde bar spring 32, and the pin will then move to the outer camming surface 22c for performance of a pump stroke (FIG. 2).
This will reposition the tube plnchers 24, 25 to close the intake tube 16, open the output tube 17, and generate a 30 control signal via the position sensor 37 to reverse the motor 13. Then the cam 22 will reverse, because the motor 13 is reversed, and the cam will rotate while capturing the slide bar pln 23a on its outer cammlng surface 23c. The cam 22 wlll go through another 180 cycle in the reverse direction while again stretching the slide bar spring 32~
thls time because the slide bar center is on the other slde of the cam center. At the end of the 130 cycle, the sllde bar pin 23a will agaln drop of~ the outer cammlng surface 22c, and move to the inner camming surface 22b where it started ~FIG. 5). In thls way, the slide bar 23 oscillates intermittently between its two extreme posltlons to plvot the tube pinchers 24, 25 and open and close the intake and 10 output I.V. tubes 16, 17, precisely and positlvely at appro-priate times in the operational cycle of the syringe pump.
The syringe pump valving and motor direction con-trol ~ystem of the present invention satis~ies a long exlstlng need ~or improved, relatively slmple~ economical, reliable, stable and accurate valving and motor control systems for such syringe pumps. The system provides extremely precise valve control without the need for separ-ate valves in the syringe itself and provides precise motor direction control in perfect synchronism with the opening 20 and closing o~ the syringe intake and output tubes.
It will be apparent ~rom the foregoing that, while particular forms of the invention have been lllustrated and described, various modification~ can be made without departing from the spirit and scope of the invention.
Accordingly, lt is not lntended that the invention be llmited, except as by the appended claims.
; .
': `
Claims (23)
1. Apparatus for use in a syringe pump having a housing and intake and output flexible IV tubes, said apparatus comprising: a pair of movable tube pinchers positioned adjacent the IV tubes to normally pinch off the tubes; drive means for alternately positioned said tube pinchers to open and close said IV tubes in proper sequence for performance of fill and pump strokes by the syringe pump; cam means within the housing in the vicinity of said tube pinchers; and cam follower means consisting of a single member positioned by said cam means for controlling substantially simultaneous snap action position-ing of both of said tube pinchers so that said positioning maintains a one tube always open and one tube always closed relationship.
2. The apparatus as claimed in Claim 1, and further compris-ing: sensing means responsive to the position of at least one of said tube pinchers for generating an electrical signal to determine whether the next stroke performed by the syringe pump will be a fill stroke or a pump stroke.
3. The apparatus as claimed in Claim 1, wherein each of said tube pinchers is substantially L-shaped having a longer arm and a shorter arm.
4. The apparatus as claimed in Claim 1, and further including: a tube pincher spring connected between said tube pin-chers and biasing both of said tube pinchers toward the tube closing position.
5. The apparatus as claimed in Claim 1, wherein said cam means includes a pair of camming surfaces, one of said camming sur-faces conditioning said syringe pump for performance of a fill stroke, the other of said camming surfaces conditioning the syringe pump for performance of a pump stroke.
6. The apparatus as claimed in Claim 1, wherein said single member comprises a reciprocating, intermittent motion slide bar located between said tube pinchers and adapted to alternately move said tube pinchers, said slide bar being controlled by said cam.
7. The apparatus as claimed in Claim 6, wherein said slide bar reciprocates between two positions, and each end of said slide bar alternately contacts or is spaced away from the adjacent one of said tube pinchers depending upon which of said two positions is assumed by said slide bar.
8. The apparatus as claimed in Claim 7, and further in-cluding: means for rotating said cam; a slide bar spring, controlled by said cam, for driving said slide bar between said two positions.
9. The apparatus as claimed in Claim 8, wherein said cam includes a pair of camming surfaces for tensioning said slide bar spring while maintaining said slide bar in one or the other of said two positions.
10. The apparatus as claimed in Claim 9, wherein the center of said slide bar is offset from the center of rotation of said cam in either of said two positions of said slide bar.
11. The apparatus as claimed in Claim 2 including syringe means supported by said housing for performing alternate fill and pump strokes to control the flow of liquid to a patient.
12. The apparatus as claimed in Claim 11, and further com-prising: motor means within said housing for driving said syringe means for performance of said fill and pump strokes.
13. The apparatus as claimed in Claim 9, wherein said cam is a rotary cam driven by said means for rotating, said cam having an arcuate, semi-circular ridge defining inner and outer cam surfaces;
and including a slide bar pin projecting from one face of said slide bar and engaging one or the other of said inner and outer cam sur-faces; and wherein said slide bar spring has one end secured to the center of said slide bar, the other end of said slide bar spring being secured to said rotary cam.
and including a slide bar pin projecting from one face of said slide bar and engaging one or the other of said inner and outer cam sur-faces; and wherein said slide bar spring has one end secured to the center of said slide bar, the other end of said slide bar spring being secured to said rotary cam.
14. The apparatus as claimed in Claim 2, wherein said sensing means includes: a reference light source and photoelectric sensor maintained in a fixed position; and an opaque member carried by one of said tube pinchers and adapted to interrupt the light beam from said reference light sources in one position of the tube pincher while being withdrawn from said light beam in the other position of said tube pincher, whereby said electrical signal is generated indi-cating the required direction of rotation of said motor.
15. The apparatus as claimed in Claim 13, wherein said ridge defines a 180° arc.
16. The apparatus as claimed in Claim 13, wherein said other end of said slide bar spring is secured to said rotary cam adjacent the outer periphery of said cam.
17. The apparatus as claimed in Claim 12, wherein: said syringe means comprises a syringe having inlet and outlet ports and a piston slidably received within said syringe, said syringe having no valves for said inlet and outlet ports; said motor means is adapted to reciprocate said piston; and said IV tubes comprise an intake IV
tube coupled to said inlet port, and an outlet IV tube coupled to said outlet port.
tube coupled to said inlet port, and an outlet IV tube coupled to said outlet port.
18. The apparatus a s claimed in Claim 17, wherein said motor means also drives said means for alternately pivoting said tube pin-chers.
19. The apparatus as claimed in Claim 12, wherein said motor means is a d.c. stepping motor.
20. The apparatus as claimed in Claim 17, wherein said syringe is disposable.
21. The apparatus as claimed in Claim 12, and further including; means responsive to said sensing means for controlling the direction of movement of said motor means.
22. The apparatus as claimed in Claim 3, wherein one edge of said shorter arm defines a tube pincher blade adapted to clamp off an IV tube.
23. The apparatus as claimed in Claim 10, wherein each end of said slide bar is fitted with a bumper bad through which said slide bar alternately contacts said tube pinchers.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA311,486A CA1058468A (en) | 1975-02-28 | 1978-09-18 | Syringe pump valving amd motor direction control system |
| CA311,487A CA1058997A (en) | 1975-02-28 | 1978-09-18 | Syringe pump valving control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/554,091 US3994294A (en) | 1975-02-28 | 1975-02-28 | Syringe pump valving and motor direction control system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1058467A true CA1058467A (en) | 1979-07-17 |
Family
ID=24212035
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA228,728A Expired CA1058467A (en) | 1975-02-28 | 1975-06-06 | Syringe pump valving and motor direction control system |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US3994294A (en) |
| JP (1) | JPS51101389A (en) |
| CA (1) | CA1058467A (en) |
| DE (1) | DE2533315A1 (en) |
| GB (3) | GB1512834A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8403888B2 (en) | 2010-04-15 | 2013-03-26 | Teneo Innovations Inc. | Device and electronic controller for syringe piston control |
Families Citing this family (46)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4091810A (en) * | 1975-11-03 | 1978-05-30 | Valleylab | Method for intravenous feeding of a patient |
| US4139008A (en) * | 1975-11-21 | 1979-02-13 | Wolfgang Wagner | Controlled-dose injection apparatus |
| US4061142A (en) * | 1976-06-16 | 1977-12-06 | Sandoz, Inc. | Apparatus for controlling blood flow |
| US4121584A (en) * | 1976-10-15 | 1978-10-24 | R. Scott Turner | Method and apparatus for controlling the dispensing of fluid |
| US4181245A (en) * | 1978-02-17 | 1980-01-01 | Baxter Travenol Laboratories, Inc. | Casette for use with an I.V. infusion controller |
| US4207871A (en) * | 1978-06-07 | 1980-06-17 | Imed Corporation | System for controlling the flow of intravenous fluids to a patient |
| US4391600A (en) * | 1979-03-09 | 1983-07-05 | Avi, Inc. | Nonpulsating IV pump and disposable pump chamber |
| US4410322A (en) * | 1979-03-09 | 1983-10-18 | Avi, Inc. | Nonpulsating TV pump and disposable pump chamber |
| US4382753A (en) * | 1979-03-09 | 1983-05-10 | Avi, Inc. | Nonpulsating IV pump and disposable pump chamber |
| US4474309A (en) * | 1981-10-22 | 1984-10-02 | Oximetrix, Inc. | Stepping motor control procedure for achieving variable rate, quasi-continuous fluid infusion |
| US4601702A (en) * | 1984-05-21 | 1986-07-22 | Quest Medical, Inc. | Volumetric infusion actuator |
| US4681568A (en) * | 1984-10-29 | 1987-07-21 | Mcneilab, Inc. | Valve apparatus for photoactivation patient treatment system |
| US4673389A (en) * | 1984-11-29 | 1987-06-16 | Minnesota Mining And Manufacturing Company | Sequence valve for piggyback IV administration |
| EP0293592B1 (en) * | 1987-05-01 | 1992-11-25 | Abbott Laboratories | Disposable fluid infusion pumping chamber cassette and drive mechanism thereof |
| US4818186A (en) * | 1987-05-01 | 1989-04-04 | Abbott Laboratories | Drive mechanism for disposable fluid infusion pumping cassette |
| US4857048A (en) * | 1987-05-29 | 1989-08-15 | Hewlett-Packard Company | IV pump and disposable flow chamber with flow control |
| US4850807A (en) * | 1987-06-16 | 1989-07-25 | Frantz Medical Development Ltd. | Disposable cassette for fluid delivery pump systems |
| US4845487A (en) * | 1987-07-20 | 1989-07-04 | Frantz Medical Development Ltd. | Pump system for enteral/parenteral fluid control and delivery |
| US4838860A (en) * | 1987-06-26 | 1989-06-13 | Pump Controller Corporation | Infusion pump |
| US4898579A (en) * | 1987-06-26 | 1990-02-06 | Pump Controller Corporation | Infusion pump |
| US5237309A (en) * | 1987-07-20 | 1993-08-17 | Frantz Medical Development, Ltd. | Pump cassette and method of pumping |
| US5246347A (en) * | 1988-05-17 | 1993-09-21 | Patients Solutions, Inc. | Infusion device with disposable elements |
| US5074756A (en) * | 1988-05-17 | 1991-12-24 | Patient Solutions, Inc. | Infusion device with disposable elements |
| US5803712A (en) * | 1988-05-17 | 1998-09-08 | Patient Solutions, Inc. | Method of measuring an occlusion in an infusion device with disposable elements |
| US5409194A (en) * | 1990-04-12 | 1995-04-25 | Crouzet Electromenager | Variable flow electrically controlled valve |
| US5290239A (en) * | 1991-09-26 | 1994-03-01 | Baxter International, Inc. | Intravenous tube safety apparatus |
| US5407424A (en) * | 1993-02-24 | 1995-04-18 | Scimed Life Systems, Inc. | Angioplasty perfusion pump |
| US5398851A (en) * | 1993-08-06 | 1995-03-21 | River Medical, Inc. | Liquid delivery device |
| US5398850A (en) * | 1993-08-06 | 1995-03-21 | River Medical, Inc. | Gas delivery apparatus for infusion |
| US5443453A (en) * | 1994-04-21 | 1995-08-22 | Sherwood Medical Company | Stop-cock valve |
| DK0744163T3 (en) | 1995-05-26 | 2000-04-10 | Schneider Europ Gmbh | Stent expansion system using a pulsating fluid |
| USD379492S (en) * | 1995-06-05 | 1997-05-27 | Sherwood Medical Company | Stop-cock valve |
| US5700245A (en) * | 1995-07-13 | 1997-12-23 | Winfield Medical | Apparatus for the generation of gas pressure for controlled fluid delivery |
| US5916197A (en) * | 1997-02-14 | 1999-06-29 | Medrad, Inc. | Injection system, pump system for use therein and method of use of pumping system |
| US5722979A (en) * | 1997-04-08 | 1998-03-03 | Schneider (Usa) Inc. | Pressure assisted ultrasonic balloon catheter and method of using same |
| GB2327895B (en) * | 1997-08-08 | 2001-08-08 | Electrosols Ltd | A dispensing device |
| US6117115A (en) | 1998-10-12 | 2000-09-12 | B. Braun Medical, Inc. | Medical tubing slide clamp device for determining proper tubing size and functional characteristics |
| US6428509B1 (en) | 1999-07-29 | 2002-08-06 | Alaris Medical Systems, Inc. | Syringe plunger driver system and method |
| US8377039B2 (en) | 2002-10-04 | 2013-02-19 | Nxstage Medical, Inc. | Injection site for male luer or other tubular connector |
| US20050107757A1 (en) * | 2003-11-14 | 2005-05-19 | Ipas | Medical vacuum aspiration device |
| US9233203B2 (en) | 2005-05-06 | 2016-01-12 | Medtronic Minimed, Inc. | Medical needles for damping motion |
| ES2727938T3 (en) * | 2007-09-28 | 2019-10-21 | Calibra Medical Llc | Disposable infusion device with dual valve system |
| US9480791B2 (en) * | 2009-12-21 | 2016-11-01 | Bayer Healthcare Llc | Pumping devices, systems and methods for use with medical fluids including compensation for variations in pressure or flow rate |
| US8944780B2 (en) | 2011-03-25 | 2015-02-03 | Bayer Medical Care Inc. | Pumping devices, systems including multiple pistons and methods for use with medical fluids |
| WO2013043889A1 (en) | 2011-09-21 | 2013-03-28 | Medrad, Inc. | System and assembly method for a fluid pump device for a continuous multi-fluid delivery system |
| EP3242649A4 (en) | 2015-01-09 | 2019-01-09 | Bayer Healthcare LLC | Multiple fluid delivery system with multi-use disposable set and features thereof |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR637504A (en) * | 1927-07-12 | 1928-05-02 | Medical device for moving liquid or gas | |
| US2625932A (en) * | 1949-01-10 | 1953-01-20 | Peter F Salisbury | Blood transfer apparatus |
| US2625933A (en) * | 1949-05-10 | 1953-01-20 | Peter F Salisbury | Blood transfer mechanism |
| GB1114247A (en) * | 1964-06-01 | 1968-05-22 | Holger Hesse | Infusion apparatus |
| US3359910A (en) * | 1965-06-10 | 1967-12-26 | Little Inc A | Apparatus for programming fluid flow |
| US3550619A (en) * | 1968-06-21 | 1970-12-29 | Becton Dickinson Co | Tubing holder |
| US3654959A (en) * | 1970-09-04 | 1972-04-11 | Technicon Instr | Fluid supply control method and apparatus for periodic, precise fluid merger |
| US3731679A (en) * | 1970-10-19 | 1973-05-08 | Sherwood Medical Ind Inc | Infusion system |
| US3963151A (en) * | 1974-08-05 | 1976-06-15 | Becton, Dickinson And Company | Fluid dispensing system |
-
1975
- 1975-02-28 US US05/554,091 patent/US3994294A/en not_active Expired - Lifetime
- 1975-06-06 CA CA228,728A patent/CA1058467A/en not_active Expired
- 1975-06-11 GB GB24943/75A patent/GB1512834A/en not_active Expired
- 1975-06-11 GB GB50886/77A patent/GB1512835A/en not_active Expired
- 1975-06-11 GB GB50887/77A patent/GB1512836A/en not_active Expired
- 1975-07-15 JP JP50085929A patent/JPS51101389A/ja active Pending
- 1975-07-25 DE DE19752533315 patent/DE2533315A1/en not_active Ceased
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8403888B2 (en) | 2010-04-15 | 2013-03-26 | Teneo Innovations Inc. | Device and electronic controller for syringe piston control |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS51101389A (en) | 1976-09-07 |
| GB1512835A (en) | 1978-06-01 |
| US3994294A (en) | 1976-11-30 |
| GB1512834A (en) | 1978-06-01 |
| GB1512836A (en) | 1978-06-01 |
| DE2533315A1 (en) | 1976-09-09 |
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