US3628094A - Apparatus of medical and other types - Google Patents
Apparatus of medical and other types Download PDFInfo
- Publication number
- US3628094A US3628094A US74566A US3628094DA US3628094A US 3628094 A US3628094 A US 3628094A US 74566 A US74566 A US 74566A US 3628094D A US3628094D A US 3628094DA US 3628094 A US3628094 A US 3628094A
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- United States
- Prior art keywords
- conductor
- winding
- hot
- solenoid
- voltage
- 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 - Lifetime
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-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
- H02H11/002—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of inverted polarity or connection; with switching for obtaining correct connection
-
- 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
- Y10S128/908—Patient protection from electric shock
Definitions
- the present invention relates to medical, dental and other apparatus which may contact a living being unsafely due to fault in the connection of the apparatus to the electrical source for energizing the apparatus.
- connection may be made by polarized plugs which through wear can be inserted wrongly, so that what is nominally the hot" conductor connecting the hot side of the electrical source, is actually the neutral" conductor, and vice versa, that is to say, the connections are transposed.
- there may be discontinuity in a ground" conductor, for example.
- connection faults namely, transposition and discontinuity
- these types of connection faults may create leakage currents througha living being contacting the apparatus, and at levels dangerous to that being. In some cases, too, such faults may be harmful to the apparatus.
- the apparatus may be provided with fault sensing means, such as a ground detector, fuse, or the like, whichresponds to the existence of a fault by disconnecting the apparatus; an isolating transformer may be interposed between electrical source and apparatus, and so forth.
- fault sensing means such as a ground detector, fuse, or the like, whichresponds to the existence of a fault by disconnecting the apparatus; an isolating transformer may be interposed between electrical source and apparatus, and so forth.
- a safety devices enses the electrical nature of the connections upon the connection being made, and if this electrical nature is incorrect, prevents the source from energizing the apparatusJMore particularly, the device senses voltages, and if these indicate'a transposition and/or discontinuity fault, the device operates relays, latches or the like, which in effect prevents the apparatus from being energized at all. Accordingly, if measures such as polarization, grounding, etc., fail, the present invention detects such failure and prevents energization. Further, since the present invention acts in response to voltage, it acts before fault current can flow in a living being in contact with the apparatus.
- the utility of the present invention extends from use with hand tools used by individuals in good health, to use with electroencephalography apparatus, electrical surgical apparatus, and the like, wherein the tissues of a living being, very commonly in ill health, have low electrical resistance contact with apparatus electrodes, as well as electrical contact with other structures of the apparatus and the immediate environment.
- the connection of the apparatus to the energy source is by means of a hot conductor and a neutral conductor, and there is alsoa ground conductor
- the safety device includes a differential transformer having a pair of primary windings, one of which is to be energized by the voltage between hot and neutral, and the other of which is to be energized by the voltage between hot and ground.
- the transformer also has a secondary winding, and this is so related to the primary windings that unless there is voltage across both primaries, and the voltages are properly related there is a voltage across the secondary.
- the safety device includes a switch for allowing the apparatus to be energized, i.e,, for turning it on,but if there is a voltage across the secondary, the switch is prevented from turning the apparatus
- the hot to ground and hot to neutral voltages fire a pair of silicon controlled rectifiers, or similar devices.
- the rectifiers are in series with each other and with a solenoid for which when energized causes a relay to permit the apparatus to be turned on.
- a first solenoid is energized by hot to ground voltage to unlatch the switch for turning the apparatus on.
- -A second solenoid is energized by hot to neutral voltage to allow the switch to be latched on.
- the safety device is preferably a more or less integral part of the apparatus with which it is used. This is because the faults with which the invention deals arise externally of the apparatus, and in its connections to the electrical source which energizes.
- a corresponding plug, having female connectors provides, with the male connectors, the ground, neutral, and hot terminals of the system.
- the safety device of the invention preferably provides the termination of the power cord at the apparatus, so faults occuring between the apparatus and the energy source will prevent the apparatus from being turned on, if there is a discontinuity or conductor transposition in the connections at any point between source and safety device.
- either plug may be incorrectly wired, they may be joined together in wrong polarity, the ground connection may be broken, and so on, and the safety device will detect this and prevent the apparatus from being manually switched on by the operator of the apparatus.
- FIG. I is a'schematic diagram of a safety device according to the invention in connection with a source ofelectrical energy and'apparatus connected to said source;
- FIG. 2 shows a safety device having a differential transformer and so much of FIG. 1 as is necessary to illustrate the operation of the safety device with the transformer;
- FIGS. 3 and 4 show other varieties of differential transformcrs usable in place of that of FIG. 2;
- FIG. 5 shows a safety device having silicon controlled rectiflers (SCRs) and'so much of FIG. 1 as is necessary to illustrate the operation of the safety device with the SCR's;
- SCRs silicon controlled rectiflers
- FIG. 6 shows a safety device having solenoids and so much of FIG. I as is necessary to illustrate the operation of the safety device with the solenoids;
- FIG. 7 shows a safety device like that of FIG. 5 as used in a transformer-isolated system.
- reference numerals l, 2 and 3 designate the respective hot, neutral and ground terminals at the plug-in or other connection of the respective hot, neutral and ground conductors 7, 8 and 9, by means of which electrically energizeable apparatus A is to be energized by a source AC of electrical energy.
- Voltage sensing means V is connected at points 7, 8 and 9 to conductors 4, 5 and 6, respectively, for controlling a switch S in accordance with the relationship among the voltages at the said points.
- Switch S has movable contactors 10, ll and 12 for conductively bridging the electrical discontinuity of the respective fixed-contact pairs 13 and l4, l5 and I6, and 17 and 18.
- the dashed-line ganging l9 represents mechanism of switch S for moving contactors 10, 11 and 12.
- the contactors I0, 11' and 12 move in unison, and are normally open. It is to be further supposed that points 7, 8 and 9 and the system of contacts 13 through 18 are structurally integrated as intimately as practical with the portions of apparatus A with which they connect electrically.
- the first of these portions is represented by impedance 2, representing the electrical load to be driven by source AC and the second of these portions is represented by impedance Z, representing that part of the apparatus which is not supposed to be energized.
- Normally, 2 will include the leakage impedance, to housing or chassis structure, of electrodes, tools, or the like, for contacting a human being.
- means V The functionof the means V is to look" at the voltages at terminals 1, 2 and 3, in order to see if they are appropriate for electrically connecting 2 and Z to them. lf they are, then means V tells switch S to close the contact pairs 13 and 14, and 16, and 17 and 18. If not, means V remains silent, so to speak, so the contacts 10, 11 and 12 remain in the condition illustrated, and apparatus A remains electrically isolated from source AC.
- terminals 1, 2 and 3 represent a plug-in connection. Then the ends of conductors 4, 5 and 6 at the terminals are incorporated in a plug, normally having male electrodes, and the connections of ground and source AC at the terminals are incorporated in a plug, normally having female electrodes.
- means V The basic action of means V is to operate switch S only if it senses source voltage between terminals 7 and 8, and between terminals 7 and 9, simultaneously. Thus, if conductor 4 is connected to terminal 2, and conductor 5 is connected to terminal 1, then if 2;, is sufficiently small, then there is substantially zero voltage between points 7 and 8. Or, if instead there is electrical discontinuity between point 9 and ground G, then there will be zero voltage between terminals 7 and 9.
- FIG. 2 shows a preferred embodiment of my invention, only so much of FIG. 1 being shown in FIG. 2 as is necessary to show how the added detail fits into FIG. 1.
- the switch S is driven by a solenoid 30 suitably mechanically connected, by means not shown, to the ganging 19.
- a solenoid 30 suitably mechanically connected, by means not shown, to the ganging 19.
- the switch is biased closed so that if the solenoid is deenergized, the contacts 10, 11 and 12 automatically resume their closed positions.
- the contacts 20, 21 and 22, on the other hand, having suitable ganging 29, are manually operated as by toggle or rocker T which one pushes one way or the other to open or close the contacts 23 through 28, as desired.
- toggle T Before connecting the conductors 3, 4 and 5 to the source, toggle T is pushed to bring contacts 20, 21 and 22 to the positions shown. The connections are then made, upon which voltage sensing means V, in the form of a differential transformer having primary windings 30 and 31, secondary winding 32, and cores 33 and 34, is enabled to see what voltages exist at points 7, 8 and 9.
- voltage sensing means V in the form of a differential transformer having primary windings 30 and 31, secondary winding 32, and cores 33 and 34, is enabled to see what voltages exist at points 7, 8 and 9.
- windings 30 and 31 are connected across points 7 and 8, and points 7 and 9, respectively, and are wound on cores 33 and 34, respectively, each winding inducing flux only in its respective core. Further the winding senses are such that when the voltages at 7, 8 and 9 are correct, the flux in core 34 is opposite in sense to the flux in core 33, insofar as inducing voltages in winding 32 is concerned.
- Secondary winding 32 is wound over both cores and therefore when the core flux changes has voltage induced therein proportional to the algebraic sum of the fluxes in the cores.
- solenoid 130 As winding 32 is connected to the winding 35 of a solenoid 130, the solenoid becomes energized whenever one of the fault conditions described supra exists. When energized, solenoid of course actuates contacts 10, 11 and 12 to open position. Therefore, when one initially connects conductors 3, 4 and 5 to terminals 1, 2 and 3, solenoid 130 immediately breaks the electrical continuity at contact pairs 13 and 14, 15 and 16, and 17 and 18, if there is a fault at the time the connection is made. Hence, operating toggle T cannot turn apparatus A on unless there is not fault.
- contact system 20-28 can be provided with a latch L, which will latch the contacts on, provided the solenoid 130 has not acted.
- the solenoid 130 can be caused to disable the latch through ganging 19, so that when the solenoid is energized, the contact system 20 through 28 will not latch closed, and thereby the operator will be apprised that there is a fault.
- the contact system 10 through 18 can be eliminated if latch L is used. In this case, the operator will operate toggle T expecting it to latch. However, when solenoid 30 energizes due to detection of a fault, the contact system 20 through 28 will not latch. This requires the contact system 20 through 28 to be normally biased open, unless the latch is operative.
- the two systems of contacts may be replaced by a manually operable circuit breaker having, in effects, contacts 20, 23 and 24,.controlling only the hot conductor, and having a solenoid structure corresponding to, and replacing solenoid 130, which when energized by voltage prevents the contactor 20 from making contacts 23 and 24, or if the contacts 23 and 24 are made, trips the contactor 20 off the contacts 23 and 24.
- a manually operable circuit breaker having, in effects, contacts 20, 23 and 24,.controlling only the hot conductor, and having a solenoid structure corresponding to, and replacing solenoid 130, which when energized by voltage prevents the contactor 20 from making contacts 23 and 24, or if the contacts 23 and 24 are made, trips the contactor 20 off the contacts 23 and 24.
- circuit breakers are well known in the art.
- windings 30 and 31 are voltage-sensing elements, it is possible to provide very fast disablement of the latch. That is, even though some fault current might flow, since it is voltage which is sensed, not fault current, the action of solenoid is not tied to sensing some predetermined level of fault current before it can disable the latch.
- the transformer is really two transformers having cores 36 and 37, and, in effect dividing winding 32 between them in the form of windings 32A and 328.
- windings 32A and 32B are wound to aid each other for like-directed fluxes in the cores, if correct connections result in oppositely directed fluxes induced by windings 30 and 31, due to their winding sense. If the winding sense of windings 30 and 31 have the opposite result on flux sense, then the windings would be wound to oppose such other for like-directed fluxes. Flux direction here would be characterized by its'clock-sense in the cores.
- the transformer has what amounts to an E-I Type core interrupted by an air gap which prevents windings 30 and 31 from being inductively related to each other.
- the core structure is analogous to that of FIG. 2, in that winding 32 is a unitary winding wound around a leg of core part 36A and a leg of core part 37A.
- the core is also analogous to that of FIG. 3 in that core pans 36A and 36B define a closed flux path equivalent to that of core 36, FIG. 3, and that core parts 37A and 37B define a closed flux path equivalent to that of core 37, FIG. 3.
- the normally open contact system through 18 is intended to be actuated manually, as by means of pushbutton P. It may be supposed that one pushes the button down to move the contacts 10, 11 and 12, by means of suitable ganging 49, to close the corresponding fixed-contact pairs. However, the system is normally latched open by a latch 38 operated through suitably ganging 39, by solenoid 130. Thus, in order to close the contact system, it is necessary to energize the solenoid 130, which then pulls the latch out of the way of the pushbutton, allowing it to be pushed down. In this case, the switch could also be constructed to latch the contact system closed.
- Solenoid 130 is energized only when an SCR 40 and an SCR 41 are firing at the same time.
- SCR 40 is fired by the voltage between points 7 and 8
- SCR 41 is fired by the voltage between points 7 and 9, so the two rectifiers correspond to windings 30 and 31, FIGS. 2, 3 and 4.
- the anode-cathode junctions of the rectifier perform the summing function of the transformer-type voltage-sensing means of FIGS. 2, 3 and 4, except that in FIG. 5, this function is utilized to unlatch the contact system 10 through 18 so that it can be manually actuated to closed state whereas, in FIGS. 2, 3 and 4 it is employed to latch the contact system into its normally open state.
- voltage divider resistances 42 and 43 provide the gates 44 and 45 of SCR's 40 and 41 with predetermined fractions of the voltages between points 7 and 8, and points 7 and 9.
- Diodes 47 and 48 protect the gate cathode junctions of the SCR's from reverse voltages, and diode 54 prevents the solenoid 130 from chattering during initial buildup of current in the relay winding.
- a normally closed switch 50 may be provided to open the connection of the SCR's to the neutral conductor at point 51.
- Latch 38 may be provided with a biasing spring 52 urging it into the position shown, until the solenoid acts, pulling latch 38 to the left and compressing the spring between structure 53 and the latch, structure 53 representing stationary structure for supporting the latch, and other elements of the contact system. Accordingly, whenever the contact system is actuated to open condition, latch 38 will return to the position shown, and prevent actuating pushbutton P again, unless the solenoid is energized. Naturally, switch 50 must be closed before pushbutton P can be actuated again.
- FIG. 6 the structure corresponding to ganging 49 of FIG. 5 is shown as including a rigid stem 56 having a spur 57 projecting rigidly therefrom.
- solenoid 130, latch 38 and spring 52 is provided to prevent pushbutton P from actuating the contact system to closed position, unless solenoid 130 is energized to shift latch 38 from the path of spur 57.
- a second solenoid Z30, latch 138 and spring 152 are provided.
- Fixed structure 58 is also provided, corresponding to fixed structure 53 of FIG. 5, except that the former also supports and guides latch 138. Normally, latch 138 is in the position shown, unless solenoid Z30 is energized,
- latch 138 is moved by solenoid Z30 into a position over spur 57, thereby tensioning spring 157.
- the contact system 10 through 18 is modified by the inclusion of fixed contacts 9A and 9B, which are manually closed by movable contactor 12.
- Contact 9A is electrically connected to point 9, and one end of the winding of solenoid 30 is electrically connected to contact 98.
- the aforesaid mechanism compresses a spring 59 against a suitable portion of fixed structure 58. Accordingly, if the pushbutton is then released the spring 59 will force the same mechanism to actuate the contact system to the state shown.
- solenoid 230 is energized because its winding is connected between points 7 and 8.
- the mechanism including spur 57, latches 38 and 138, and so on, is so proportioned that in closed condition the spur 57 has moved far enough down to allow the latch 138 to shift to the right far enough to be in the way of spur 57 to sufficient extent to prevent the spring 59 from forcing the contact system out of its closed state, when the pushbutton P is released. Further, the proportioning is such that the latch 38 is held out of the way because the spur now occupies the space the latch 38 occupied before the solenoid pulled it out of the way of the spur.
- latch 138 does not shift to the right when the button P is actuated, then there is nothing to prevent spring 59 from pushing the button back up except the effect of spring 52 urging latch 38 against the end of the spur (note that when contacts 17 and 18 are closed by contactor 12, the connection of the winding of solenoid 130 to point 9 is open.)
- the spring 52 and the adjacent portions of latch 38 and spur 57 are designed so that friction or equivalent between latch and spur is not along sufficient to prevent the spring from opening the contact system, after the pushbutton P is released.
- FIG. 7 are shown modifications which severally or individually may be applied to one and another of the previously described embodiments of the invention.
- the contact system controlling the energization of apparatus A may be simplified to the movable contactor 11 and fixed contacts 15 and 16. Since the SCR circuitry of FIG. 5 is used here, the contact system 11, 15 and 16 is normally open. and closes only if the conditions at the connector terminals 1', 2 and 3 are correct. In passing, it is to be noted that terminals 1, 2' and 3' are shown in plug-in symbolism, but are of course equivalent to terminals 1, 2 and 3.
- Conductors 4 and 5 provide the full voltage of winding 62 across an inductance L, say the winding or windings of an electrical motor forming part of apparatus A.
- Conductor 6 connects to ground the housing or other apparatus structure which may contact the patient or the user of the apparatus, and which may more or less envelope the electrical load L and/or more or less segregate it mechanically from the patient or user.
- the detector D is commonly found in transformer-isolated systems of the sort shown in FIG. 7, but'is not essential to the operation of the SCR circuitry, etc., of FIG. 7. Usually the detector D merely signals the presence of a ground fault in apparatus A, namely, excessive leakage to ground via housing H. Such fault is not the sort of fault the present invention is intended to deal with, and is rather a possible property of the apparatus A, rather than of the connections of apparatus A to the winding 62. That is to say,the apparatus A is supposed to float off ground by reason of the isolating transformer 60, and if some part of the apparatus A has a ground fault this would not in general affect the interrelationship of the voltages on conductors 4, 5 and 6.
- What detector D does is determined on whether or not there is some voltage between ground and the conductor 6, when the connections to apparatus A are correct. If it detects no voltage, then housing H is grounded (which is safe, if not desirable), but if it detects a voltage greater than some predetermined magnitude, then that voltage exists between some part of the apparatus and ground, and is a potential hazard to the user or patient.
- a safety device operatively associated with said apparatus for preventing fault from causing said apparatus to be in unsafe electrical contact with said living being;
- said apparatus having a hot conductor, a neutral conductor and a ground conductor, said hot conductor being connected to a first portion of said apparatus and being adapted to connect said first portion to the hot terminal of a source of electricaleneljgy,
- said neutral conductor being connected to said first portion and being adapted to connect said first portion to the neutral terminal of said source
- said ground conductor being adapted to connect a second portion of said apparatus to a ground terminal
- said safety device including a switch normally interrupting electrical continuity of said hot conductor at a place between the said hot terminal and said first portion, said switch being normally independently operable of the rest of said faultproofing device, for establishing electrical continuity at said place;
- said safety device also including voltage-sensing means connected in voltage-sensing relation to said conductors at points between said portions, on the one hand, and said terminals, on the other hand;
- said voltage-sensing means being connected to said switch and being responsive to the several voltages at said points to substantially prevent said switch from being operative to establish electrical continuity at said place, under any one of the following conditions: electrical discontinuity in said neutral conductor; electrical discontinuity in said ground conductor; connecting said hot conductor to said ground terminal and said ground conductor said hot terminal; connecting said hot conductor to said neutral terminal and said neutral conductor to said hot terminal; connecting said neutral conductor to said ground terminal and said ground conductor to said neutral terminal, provided said neutral and ground terminals are at different potentials.
- said switch has first and second contacts and a movable contactor movable from one said contact to the other and said contactor being effectively connected to said ground conductor at all times; said solenoid being connected between said first contact and said hot conductor:
- said solenoid having a latch and said switch having a movable member movable to first and second positions, said first position being one in which said hot conductor has its said electrical continuity interrupted and said movable contactor contacts said first contact, and said second position being one in which said electrical continuity is established and said contactor contacts said second contact;
- said latch being normally positioned to obstruct movement of said movable member from said first position to said second position, so long as said solenoid is not energized, but being responsive to energization of said solenoid to move out of the way of said movable member, said solenoid being said voltage sensing means.
- said safety device includes means responsive to voltage between said hot conductor and one of the other said conductors, and to said switch being in said second position, for latching said switch in said second position.
- said second solenoid being, with the first said solenoid, said voltage sensing means;
- said second latch being normally positioned to allow movement of said movable member from said first position to said second position, but being responsive to energization of said second solenoid and to movement of said movable member to said second position to move to a position obstructing movement of said second member to said first position, so long as said second solenoid is energized.
- said safety device includes a second switch and third switch, said second and third switches being normally open and being connected in series with one another and with a solenoid, between said neutral and hot conductors, said voltage-sensing means including means connected to said second and third switches for closing both said second and third switches in response to said voltage-sensing means sensing substantially the voltage of said source both between said hot conductor and said ground conductor, and between said conductor and said neutral s l ct rz the first said switch being a movable member movable to first and second positions;
- said first position being one in which each said conductor is electrically interrupted between said apparatus and said thereon.
- said second position being one in which said conductor is electrically continuous between said faultproofing device and said apparatus;
- said first switch having a latch normally positioned to obstruct movement of said member from said first position to said second position, but responsive to energization of said solenoid to move out of the way of said member.
- safety device and said voltage-sensing means includes first core means, second core means, primary windings on said core means, and a secondary winding on said core means;
- one said primary winding being connected between said hot conductor and said neutral conductor for producing first flux in said first core means when there is voltage between said hot conductor and said neutral conductor
- a second said primary winding being connected between said hot conductor and said ground conductor for producing second flux in said second core means when there is voltage between said hot conductor and said ground conductor
- said first and second core means being arranged so that said first flux and said second flux are mutually independent of each other
- said switch including means connected across said secondary winding to cause said switch to establish electrical continuity at said place only when said last two said voltages have the same sense and substantially the same magnitude.
- said core means comprises two cores each having one and another of saidFrimary windings thereon, and both having said secondary winding 8.
- said core means comprises two cores, each of said cores having a primary winding and 21 secondary winding thereon, the last said primary winding being the former said primary windings and each of the last said secondary windings being together the first said secondary winding.
- a safety device for providing interconnection of an electrically energizable apparatus with a hot terminal, a neutral terminal and a ground terminal, said device having a first winding for connection between said hot terminal and said neutral terminal, a second winding for connection between said hot terminal and said ground terminal, a third winding, a first core means inductively relating said first winding to said third winding, and a second core means inductively relating said second winding to said third winding, said first winding being noninductively related to said second winding;
- said safety device including switch means for manually interrupting electrical continuity of said interconnection, and being connected to said third winding for responding to voltage therein to restore said continuity when and only when said third winding has voltage therein corresponding to correct interconnection of said apparatus with said terminals, and correct voltages at said terminals.
- said third winding has one part wound solely on one said core means and another part wound solely on the other said core means.
Abstract
Description
Claims (11)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US7456670A | 1970-09-23 | 1970-09-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3628094A true US3628094A (en) | 1971-12-14 |
Family
ID=22120254
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US74566A Expired - Lifetime US3628094A (en) | 1970-09-23 | 1970-09-23 | Apparatus of medical and other types |
Country Status (5)
Country | Link |
---|---|
US (1) | US3628094A (en) |
CA (1) | CA934469A (en) |
DE (1) | DE2147425A1 (en) |
FR (1) | FR2107906B3 (en) |
IT (1) | IT942176B (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3761769A (en) * | 1972-09-10 | 1973-09-25 | Sybron Corp | Safety devices for electrical apparatus of medical and other types |
US3857383A (en) * | 1970-05-11 | 1974-12-31 | Int Health Systems | Multiphasic health screening method and module |
US3886932A (en) * | 1973-08-08 | 1975-06-03 | Schwarzer Gmbh Fritz | Overcurrent protective circuit |
US3897787A (en) * | 1972-12-29 | 1975-08-05 | Olympus Optical Co | Power source device for an electric surgical knife |
US3933157A (en) * | 1973-10-23 | 1976-01-20 | Aktiebolaget Stille-Werner | Test and control device for electrosurgical apparatus |
US4122854A (en) * | 1973-08-23 | 1978-10-31 | Matburn (Holdings) Limited | Electrosurgical apparatus |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU670943B2 (en) * | 1992-07-14 | 1996-08-08 | Gewiss Spa | Electrical distribution device with preventive checking of the state of the load, particularly for civil and industrial users |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3213321A (en) * | 1963-05-31 | 1965-10-19 | Charles F Dalziel | Miniature differential circuit breaker |
US3376477A (en) * | 1965-12-06 | 1968-04-02 | Hubbell Inc Harvey | Protective circuit |
US3435292A (en) * | 1966-04-26 | 1969-03-25 | Arulanandasami Joseph Stephen | Electric shock control device |
-
1970
- 1970-09-23 US US74566A patent/US3628094A/en not_active Expired - Lifetime
-
1971
- 1971-09-15 IT IT52900/71A patent/IT942176B/en active
- 1971-09-15 CA CA122917A patent/CA934469A/en not_active Expired
- 1971-09-22 FR FR7134139A patent/FR2107906B3/fr not_active Expired
- 1971-09-22 DE DE19712147425 patent/DE2147425A1/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3213321A (en) * | 1963-05-31 | 1965-10-19 | Charles F Dalziel | Miniature differential circuit breaker |
US3376477A (en) * | 1965-12-06 | 1968-04-02 | Hubbell Inc Harvey | Protective circuit |
US3435292A (en) * | 1966-04-26 | 1969-03-25 | Arulanandasami Joseph Stephen | Electric shock control device |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3857383A (en) * | 1970-05-11 | 1974-12-31 | Int Health Systems | Multiphasic health screening method and module |
US3761769A (en) * | 1972-09-10 | 1973-09-25 | Sybron Corp | Safety devices for electrical apparatus of medical and other types |
US3897787A (en) * | 1972-12-29 | 1975-08-05 | Olympus Optical Co | Power source device for an electric surgical knife |
US3886932A (en) * | 1973-08-08 | 1975-06-03 | Schwarzer Gmbh Fritz | Overcurrent protective circuit |
US4122854A (en) * | 1973-08-23 | 1978-10-31 | Matburn (Holdings) Limited | Electrosurgical apparatus |
US3933157A (en) * | 1973-10-23 | 1976-01-20 | Aktiebolaget Stille-Werner | Test and control device for electrosurgical apparatus |
Also Published As
Publication number | Publication date |
---|---|
FR2107906B3 (en) | 1974-05-10 |
DE2147425A1 (en) | 1972-03-30 |
CA934469A (en) | 1973-09-25 |
FR2107906A3 (en) | 1972-05-12 |
IT942176B (en) | 1973-03-20 |
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