CA1049717A

CA1049717A - Ultrasonic hand held cleaning device and method

Info

Publication number: CA1049717A
Application number: CA218,130A
Authority: CA
Inventors: Rene J. Perdreaux (Jr.)
Original assignee: Cavitron Corp
Current assignee: Cavitron Corp
Priority date: 1974-03-19
Filing date: 1975-01-17
Publication date: 1979-03-06
Also published as: HK16182A; DE2508175A1; DE2508175C2; DK110475A; JPS6159728B2; FR2264518A1; US3956826A; SE410141B; NO137772C; DK137944B; SE7503043L; GB1483184A; FR2264518B1; JPS50132791A; BR7501148A; AR202167A1; IT1031307B; JPS5925738A; NO137772B; AU7823175A

Abstract

ABSTRACT

An ultrasonic hand-held cleaning device having a housing enclosing a casing, an energizing winding about the casing, and a fluid conduit attached to the interior of the casing. A sleeve is insertably mounted into the end of the casing, and acts to support a connecting body at a spaced distance within the sleeve so as to form an annular space in fluid communication with the casing. A vibrator is attached at the casing end to the connecting body and is therefore located in the casing opposite the energizing winding.
A cleaning tool is attached at the other end of the connecting body. In one version fluid moving through the annular space is sprayed out an annular nozzle around the tool which is itself vibrating ultransonically as a result of reverberatory vibrations induced by the vibrator, In a second preferred-embodiment the connecting body has a ring at its nodal point, the sleeve being cut out to accomodate the ring and having two longitudinal slots for the passage of fluid. A tubular insert for controlling the space between the connecting body and the sleeve at the nozzle is supported by the sleeve.

Description

10497~7 This invention relat~s to an improved ultrasonic dental tool. More particularly this invention relates to apparatus which utilizes an ultra-sonically driven head in conjunction with a spray of liquid or ~lur~J con-taining abrasive material to operate as a cutting or cleaning tool in dental operations (procedures).
Acoustically vibrated cutting and cleaning devices essentially com-prise a vibrator having an electromechanical part or section which is in-duced to vibrate at relatively high frequency and small amplitude by the presence of a surrounding alternating electromagnetic field as produced by an alternating current source. The electromechanical section or part may be any one of several types such as electrodynamic, piezo-electric, or mag-netostrictive, with an operating frequency range in the order of 5,000 to ~0,000 cycles per second and a preferred frequency range in the order of 20~000 to about 30,000 cyclos per second.
Where the electromechanical section or part is magnetostrictive, one end thereof i8 fixed to a connecting body whose other end rigidly support~
a sele¢ted work tool. The connecting body serves as an acoustic impedance transformer and is 80 shaped and formed as to either enlarge or reduce the amplitude of vibrations produced by the electromechanical part or section as delivered to the work tool through the connecting body. The vibrator described above is essentially composed of an electromechanical part or - eection~ a connecting body and a work tool, which are rigidly joined end to end as a unit and supported by a suitable housing or casing, Specifically the present invention is an improv~ment on the device sho~n in United States P~tent No. 3,076~904 issued February 5, 1963 to C.
Kleesattel et al for Acoustically Vibrated Material Cutting and Removing Devices. P~ior art devices as exemplified by the device 3ho~n in the here-tofore described patent utilize a separata off-center conduit and nozzle to deliver a liquid slurry or cooling water to the tool and adjacent area.
While thera are no great disadvantages to such an offset conduit, the q~
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position of the tool and the nozzle must be ~et 50 that the li~uid is delivered in the work area~ For instance the nozzle may be so constructed to deliver water in the area of the tool tip for a tool which i5 bent away from the axis of the device.
Obviously if an unbent tool tip were in use, the fluid would not he directed towards the more appropriate location unless the nozzle direction were changed. Secondarily where the nozzIe tip stands out from the body of the device, it is more exposed to dislocation and damage.
la Accordingly, the present invention provides, for use in an ultrasonic device having a tubular casing with an open end, means in the casing for inducing ultrasonic vibration, and means for supplying a fluid into the inside of the casing, an insert comprising:
a hollow sleeve having an end portion for sealing connection to said open end of said casing;
a tool assembly having a tool tip at one end and a vibrator at the other end for producing ultrasonic vibrations in said tool assembly from said vibration inducing means when inserted into said casing, and a connecting body therebetween connecting said tool tip to said vibrator; and support means supporting said tool assembly coaxially within said hollow sleeve with said vibrator extending from said end portion of said sleeve for insertion into said casing when said sleeve is connected to said casing and with said tool tip projecting from the other end of said sleeve, and at an annular spacing from said sleeve for defining a continuous, substantially entirely annular fluid flow path external said tool assembly and from said end portion to said other end of said sleeve whereby fluid from said casing can exit at said tool tip.

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10497~7 According to another aspect of the present invention, there is provided a method of utilizing fluid in an ultrasonic device and at a work area around the ultrasonic device tool tip, the method comprising exposing vibration means in the ultrasonic device for cooling the vibration means by passing a fluid over the vibration means, and forcing the fluid from the vihration means through an annular space between a tool assembly and a hollow sleeve of the ultrasonic device for cooling the tool assembl~ which is attached to the vibration lQ means for vibrating the tool assembly and for attenuating vibratory transfer from the tool assembly to the sleeve.
An object of my invention is to provide an improved ultrasonic cleaning device.
Another object is to provide an ultrasonic cleaning device having a novel and improved liquid nozzle.
Yet another object of the device according to the ~, present invention is to provide an ultrasonic hand held device -~; with a novel cooling means~
Another object of the device according to this 2~ invention is to provide a hand held ultrasonic device with reduced apparent vibration to the operator's hand.
Still another advantage of my invention is to provide an ultrasonic cleaning device having a novel liquid spray pattern.
, Other objects and advantages of the present invention will he apparent to those skilled in the art from the descrip-tion of the drawings and preferred embodiments which follow.
- Figure 1 is a cross-sectional view of the forward end of the ultrasonic device according to my invention;
Figure 2 is a view of the rear part of the device according to my invention;

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Figure 3 is a perspective view of the device;
Figure 4 is a cross-sectional view of the forward part of another embodiment of the device according to the invention; and Figure 5 is a sectional vie~ taken along section 5-5 of Figure 4.
Acoustically vibrated cleaning devices are well known in the art. They assume many different forms and variations depending upon the design limitations, preferences, costs, materials, etc., as well as composition of the work piece and the work to be performed. The aforementioned United States Patent No. 3,076,904 is illustrative of such devices as well as the various uses, permutations and modifications which may be utilized. Other ', . ~ -.:' ", '1 ,1 -.i. , .
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permutations of such devices are illu~trated by United States Patent No

3,368,2Bo issued February 13, 1968 to G.M. Friedman et al for a Dental Tool and United States Patent No. 3,075,288 issued January 29, 1963 to L.
Balamuth et al, for a Dental Instrument. M~ invention is an improved ultra-sonic cleaning device for dental use which, among other things, advantageo-usly introduces the liquid coolant to the work area. With this in mind, a preferred embodiment of my invention is shown in FigureY 1-3 of the drawings in which the device 12 is shown in a cut-away elevational view with an outer tubular housing 1~ suitable for holding in the palm of one hand much as a pencil is held. At the non-working end of the device, an endcap 16 is threaded to the housing through the end of which a flexible tubular conduit 18 extends into the body of the device 12 . The conduit which is retained in the sndcap in a relatively conventional manner as by clip8 20 contains t~ro conducting wires 22 and 24 and a fluid supply pipe 26, all three being from conventional sources not shown.
The fluid pipe 26 i9 in~erted into the base 28 of a nipple section 30 and secured within the base by a pipe retainer 32. The nipple forms one end of a tubular casing 34 which extends axially within the housing. As shown each of the wires 22 and 24 are attached to each end of a helicallg coiled winding 36 of current conducting wire such as copper wire protected by a suitablo coating e.g. onamel. The current in the winding induces an altern-ating olectromagnetic fi61d within the casing 34 when a current i8 passed therethrough. The casing may be formed of any suitable material such as a plastic or metal material which does not impede the establishment of the alternating electromagnetic fleld within the casing as produced by the wind-ing. The casing is open at it~ anterior end~ that end having an annular flange 38 with an annular groove. An elastomeric ~ealing element such as provided by 0-ring 42 is secured within the groove and providss a tight fit ;~ and seal between the casing and the interior of the housing Anterior to tho flanged portion 38 of tho c6sing th~ interior of the houeing is reduced , ,~..

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10497~7 in diameter to sub~tantially the same diameter as the interior of the casing, The housing wall abutting the anterior of the casing i~ counterbored and then beveled toward the casing anterior face, The front end of the housing has a smaller outside diameter but retains substantially the same interior dia- -meter as the casing, An insert assembly 44 is insertably unted in the housing through the front end thereof, This is an important feature of this device in that the provision of the insert assembly 44 permits ready separation and removal Or the insert assembly from the housing and replacement with another insert assembly having a different operating configuration, The outer part of the insert assembly 44 i8 a unitary sleeve 48 with a relatively small bore therethrough, The exterior diameter of the sleeve 48 varies between its different sections, That section closest to the tool end, the anterior sec-tion 52 is of a smaller outside diameter to reduce the weight of the device -~ at this point but otherwise is as rigid as the other parts of the sleeve 48.
A central section 54 of the sleeve is of greater outsida diameter providing thereby sufficient material for thrse threaded holes 56 which are drilled and tapped transversely 120 apart through the ~leeve centsr section, A
third posterior section 58 of the sleeve has an outside diameter enabling it to be removably inserted into the anterior face of the housing in such surrace to surface contact &s to provide a tight fit therebetween. An annular slot is cut on the out~ide surface of the third section in which 0-ring 60 is placed as a sealing and securing alement, A fourth section 62 of the sleeve extends rearwardly from the third ~ection and i8 essentially a thin walled tube with the same external diameter a3 ths third section, Tho internal posterior face of the third section is countersunk to an extent ~ -which provides ease of fluid flo~ a~ described hereinafter, A tool assembly 64 i8 slidlngly held within the bores of the sleeve assembly though sub~tantial parts of this as~embly do extend out of each end of tho sleeve, The tool assembly 64 comprises a tip 66 which is located .` :

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out from the forward first section of the sleeve; the tip being generally a pointed relatively hard protrusion, though for various uses a 'soft' tip of rubber or plastic may be employed. The tip is permanently attached to one end of a solid tubular shank 68 of uniform diameter, The diameter of the - shank is somewhat smaller than the interior bore diameter of the sleeve 48, so that there is an annular space 70 formed therebetween. The shank is long enough to extend through the sleeve bore to the area of the sleeve tube where the shank is machined to a larger diameter and thereby forms a connecting body 72. The connecting body 72 has a smaller diameter than the internal diameter of the sleeve and is therefore spaced apart from the interior of the sleeve tube extension. Brazed to the connecting body is a magnetostrict-ive vibrator 74 preferably formed of a metal alloy such as permanickel, nickel, permendeur or other alloys which possess high tensile strength, and is highly magnetostrictive in character. As seen in the drawing the vibrator 74 is longitudinally located within the interior of the casing and therefore is directly and intentionally electrodynamically subject to the imposed alter-nating currents passing through the winding. Thus the transducer is pre-ferably vibrated in the frequency range of 10,000 to 40,000 cycles per sec-ond. This ultrasonic vibration is transferred through the connecting body and the shank to the tip which is thereby caused to vibrate in this range though with low amplitude. A longitudinal nodal point for the tool assembly ~ is preferably located adjacent the central section of the sleeve at the point ; where the three threaded holes are located. Set screws 76 are threadedly secured in these holes, each screw tip being in contact with the connecting ,. .~
body. The set screws 76 preferably have 'soft' tips so as not to scour the hard surface of the connecting body.
In operation a high frequency alternating current is applied from an outside source ~not shown) to the winding thereby inducing a high frequency vibration in the tool assembly and at the tip thereof. At the same time, a fluid, generally water is introduced via the conduit, passes through the : . , , . - . . . .

10497~7 pipe and into the casing, at which point there are relatively less cross-section restrictions to the fluid flow. As the water leaves the casing it first enters the restrictive annular spaces between the connecting body and the sleeve extension and then the smaller annular space between the shank and sleeve finally emerging through a nozzle 7~ formed by the shank and the end of the sleeve. Such an arrangement additionally functions to lubricate the shank and connecting body in the msr,ner of & hydrostatic bearing while at the same time causing a fluid spray pattern as shown in Figure 3 of the drawings, this pattern impinging around the operating tip of the device.
Similarly by functioning as a hydrostatic bearing utilizing the fluid flow pressure as lubricant the housing is substantially isolated from the ultrasonic vibration elements of the device. This is important for a device which is intended to be used as a hand held in~itrument, since the operator~s hands may possibly b~ sensitive to any kind of vibration. Additionally ~-the fluid~ generally water, acts to cool the casing, the vibrator, the insert assembly and the tool assembly thereby extending the lif~ of these parts and preventing the hand held instrument from becoming overheated Another feature of the device according to the preferred embodiment i9 the biasine open of the annular nozzle on the same side that work is being done by the tool. I`hat is, as the tool i9 applied to the work area, a cer- -tain amount of force i9 transferred by the tip of the tool through the tool a~sembly which acts to open somewhat that side of the nozzle 7~ which is on the side of the tool contacting the work area~ This of cour3e creates a somewhat larger flow area on that side of the tool where the work area is located, This aIlows for the greater delivery of cooling fluid to the side of the tool on which work is being done. Advantages inherent in this mode i of operation are readily apparent to one skiIled in the art.
- Another preferred embodiment of the device according to this inven- -tion is 3hown in Figure 4 of the drawings in croqs-sectional elevation of the front half of the device~ A~ shown, an in~ert assembly ~4, like insert ~ ' .
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assembly ~4 is insertably mounted in the housing, As previously mentioned the importance of this feature i9 in the ready separation and removal or in-sertion and assembly of the insert assembly within the housing, assuring ease of interchange of the insert assembly and tool tip desired. The insert B4 G comprises an outer sleeve1~ which is preferrably molded out of a structural plastic as two longitudinal halves and permanently bonded upon assembly.
The unitary sleeve 86 has a bore 90 therethrough somewhat larger than that provided in the other versions of the device described hereinbefore. This iæ because of the difficulty to a certain extent of manufacturing the plastic halves to close tolerances, For interchangability, the sleevs 84 has P rear portion 92 of the same outside diameter a9 sleeve ~4, with an annular groove thereon for place-ment of an 0-ring 96 to assure sealing and securing of the insert in the housing. The middle portion of the sleeve 84 has a relatively larger diameter to provide added strength for internal passag0s, to abutt against the housing, and to provide suffici0nt space adjacent the nodal point of the vibrating tool assembly for various cutouts.
Interior of the sleeve on the inside surface of the bore at the nodal point~ an annular groove 98 is transversely located, that i~, at the point which corresponds to the location of screws 76 on the other embodiment des-cribed herein before, The tubular 3hank 68 located within the bore has a ring 100 brazed onto the shaft adjacent the nodal point and sized to loosely fit into the groove 98. The ring 100 has a single key 102 on its outsr circumferance which key fits into one of two semi-circular bypasse~ 104 located longitudin~lly on the inner surface of the bore, 1~0 apart from each other and centered with their radius or altitude on the groove 9g. The key i9 held in one of the bypasses after as~embly. The bypa~ses therefore serve a two part function as a retainer for the key and to provide a path for fluid around the ring. ~
The front portion of the sleeve has a transvsrse groove 106 adjacent ~ -- . . . . , . ~ .

its end which groove is adapted to secure a bushing 108 which encircles the shank, The bushing has a fl~nge 110 which fits into the forward groove 106, Functionally the bushing provides an annular nozzle 112 of controlled dis-tance between its inside surf&ce and the outside of the shank regardless of the tolerances of the plastic sleeve, Similarly the bushing most likely prevents wear on the end of the sleeve which would result from the action of the exiting stream of fluid and the vibration of the ~hank, were it not present. For purposes of inducing an added amount of ~pray towards the bent side of the tool tip a longitudinal shallow channel 114 is formed on the shank extending for a distance from the interior of the sleeve bore, p~st the bushing and towards the tool tip, In point of operation both of the ver-sions of the invention described herein operate in a similar manner~ the ;~ version having the bushing and the plastic sleeve being somewhat cheaper to manufacture and including various improvements and modifications, as for in-qtance the shallow channel for directing extra water towards the area of th0 tool tip,

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. For use in an ultrasonic device having a tubular casing with an open end, means in the casing for inducing ultrasonic vibration, and means for supplying a fluid into the inside of the casing, an insert comprising:
a hollow sleeve having an end portion for sealing connection to said open end of said casing;
a tool assembly having a tool tip at one end and a vibrator at the other end for producing ultrasonic vibrations in said tool assembly from said vibration inducing means when inserted into said casing, and a connecting body therebetween connecting said tool tip to said vibrator; and support means supporting said tool assembly coaxially within said hollow sleeve with said vibrator extending from said end portion of said sleeve for insertion into said casing when said sleeve is connected to said casing and with said tool tip projecting from the other end of said sleeve, and at an annular spacing from said sleeve for defining a continuous, substantially entirely annular fluid flow path external said tool assembly and from said end portion to said other end of said sleeve whereby fluid from said casing can exit at said tool tip.

2. The insert according to claim 1 wherein said support means support said tool assembly at the approximate nodal point thereof.

3. The insert according to claim 1 wherein said annular space between said hollow sleeve and said tool assembly is sufficiently small at said tool tip to form a nozzle to induce the fluid to exit as a spray.

4. The insert according to claim 1 wherein said support means allows said tool assembly to move at said nozzle to bias the opening of said space toward the side of application of force to said tool assembly.

5. The insert as in claim 1 wherein said support means comprise arcuately spaced projections extending from the inside of said hollow sleeve to said tool assembly.

6. The insert according to claim 5 wherein said support means comprises three equally spaced screws threadedly and insertably mounted in three equal spaced threaded holes at 120°
apart on said hollow sleeve, the tip of each of said screws being in contact with said tool assembly.

7. The device according to claim 6 wherein said screws are soft tipped.

8. The insert according to claim 1 wherein said sleeve further comprises a bushing mounted internally in said sleeve adjacent said other end of said sleeve.

9. An insert as in claim 1 wherein said support means comprise a ring extending about the tool assembly to the inside of said hollow sleeve and at least one fluid bypass path extending from said annular space between said sleeve and tool assembly at each end and into said sleeve at said ring for carrying fluid past said ring.

10. In an ultrasonic device having a casing, an energyzing means adjacent said casing, means for introducing fluid into an end of said casing, and an insert assembly insertably mounted in said casing, the improved insert assembly comprising a hollow sleeve adapted to be insertably mounted in the casing and in fluid communication therewith, connecting means extending through said hollow sleeve, said connecting means being mounted at a spaced distance from the internal wall of said hollow sleeve to thereby form an annular space between said sleeve and said connecting means, said annular space being in fluid communi-cation with said casing, and a nozzle means adjacent said hollow sleeve anterior end for fluid flowing through said space to exit said nozzle means said nozzle means comprising a bush-ing mounted internally in said hollow sleeve adjacent the open anterior end thereof said bushing having an internal diameter at a spaced distance from said connecting means thereby provid-ing an annular nozzle, said connecting means additionally comprising a shank portion extending through said hollow sleeve, a shallow channel longitudinally located thereon extending from the interior of said hollow sleeve and past said bushing for providing an added stream of fluid, and a ring transversely mounted on said shank portion at the nodal point thereof, said hollow sleeve having a transverse slot adapted to accommodate said ring and flow detour means for providing fluid passages around said ring, ultrasonic vibration means fixedly connected to said connecting means at the posterior end thereof and adapted to be inserted into said casing into position to be acted upon by said energyzing means, and tool means axially fixed to said connecting means at the anterior end thereof, said tool means being vibrated by the ultrasonic vibration of said vibration means as transmitted by said connecting means.

11. A method of utilizing fluid in an ultrasonic device and at a work area around the ultrasonic device tool tip, the method comprising exposing vibration means in the ultrasonic device for cooling the vibration means by passing a fluid over the vibration means, and forcing the fluid from the vibration means through an annular space between a tool assembly and a hollow sleeve of the ultrasonic device for cooling the tool assembly which is attached to the vibration means for vibrating the tool assembly and for attenuating vibratory transfer from the tool assembly to the sleeve.

12. The method of claim 11 wherein an added fluid flow is directed at a point nearest the tool.

13. The insert as in claim 5 wherein said projections are resilient.

14. The insert as in claim 1 wherein said annular fluid flow path communicates with said casing external said vibrator when in said casing for receiving fluid from around said vibrator.

15. An insert as in claim 1, 8 or 5 wherein the end of the tool tip remote from the connecting body is bent from the axis of the sleeve and the tool tip further comprises a channel at the end of the sleeve for directing fluid from the annular flow path in the sleeve to the bent tool tip end.