US3734652A

US3734652A - Pneumatically powered device

Info

Publication number: US3734652A
Application number: US00084071A
Authority: US
Inventors: J Barnett
Original assignee: Stryker Corp
Current assignee: Stryker Corp
Priority date: 1970-10-26
Filing date: 1970-10-26
Publication date: 1973-05-22
Anticipated expiration: 1990-05-22

Abstract

A pneumatically powered device for rotating, at a relatively high speed, a tool of the type used by a surgeon for performing an operation. A self-contained air motor is removably disposed within an elongated tubular housing easily held and manipulated by the hand of the surgeon and connected by swivel means to conduits through which a gas under pressure is delivered to and carried away from one end of the air motor. Coupling means extend from the other end of the air motor for connection to a tool, such as a drill bit.

Description

tates i Barnett 1 May 22, 1973 54] PNEUMATHCALLY POWERED DEVICE John E. Barnett, Kalamazoo, Mich.

[73] Assignee: Stryker Corporation, Kalamazoo,

Mich.

22 Filed: Oct. 26, 1970 21 Appl. No.: 84,071

[75] Inventor:

4 U2 U I27 123 I 3,298,103 1/1967 Maurer ..415/503 3,502,158 3/1970 Snider ..173/163 3 ,429,230 2/1969 Quackenbush ..418/270 3,439,422 4/1969 Doeden et al. ..415/503 3,472,323 10/1969 Hall ..173/163 Primary ExaminerCarlton R. Croyle Assistant Examiner-John J. Vrablik Attorney-Woodhams, Blanchard & Flynn [57] ABSTRACT A pneumatically powered device for rotating, at a relatively high speed, a tool of the type used by a surgeon for performing an operation. A self-contained air motor is removably disposed within an elongated tubular housing easily held and manipulated by the hand of the surgeon and connected by swivel means to conduits through which a gas under pressure is delivered to and carried away from one end of the air motor. Coupling means extend from the other end of the air motor for connection to a tool, such as a drill bit.

11 Claims, 11 Drawing Figures PATENTEB HAYZ 2 I973 sum 2 OF 2 I. HWM l wn R W W Wu O Q NNQ NT /S W M N N & m I v g a A. 5 4 N m J a mm mm PNEUMATICALLY POWERED DEVICE BACKGROUND OF THE INVENTION This invention relates in general to a pneumatically powered device for rotating a surgical tool at a high rate of speed and, more particularly, to a type thereof which is swivelly connected to supply and discharge conduits for the gas under pressure which operates the motor and wherein the motor is self-contained and readily removable from a protective housing which serves as a handpiece.

The use of pneumatically powered surgical tools has become established and widespread because, for example, of the high rotational speeds which can be achieved by air motors of relatively small size by comparisonwith electric motors. In order to continue the use of electrical power sources, it has been common practice to drive a surgical tool through a long flexible cable which is connected to the electrical motor. However, the use of powerdriven surgical tools, either cable-driven or air motor-driven, has been hindered somewhat by the lack of flexibility in the movement of the handpiece or parts of the device gripped by the surgeon. Clearly, where the rotative force is furnished through a flexible cable, swivel movement of the handpiece is out of the question since it would thus permit rotation of the entire handpiece in the hands of the op erator, due to the torque developed by the cable. Moreover, in order to achieve the high rotational speeds which are desired for surgical tools, it is necessary to furnish complicated, very expensive gearing arrangements in which power may be sacrificed in order to gain speed.

On the other hand, heretofore, no feasible arrangement has been developed for permitting freely rotatable movement of the handpiece with respect to the conduits supplying and discharging the pressurized gas used to operate the air motor. Incidentally, it is considered dangerous to discharge the air from the air motor into the region where the operation is beingperformed because of contamination and other well-known reasons. Thus, at least two conduits have been required in operating an air motor as a rotative power source in an operating room.

Because air motors can be manufactured for surgical duty in relatively small sizes, it follows that the rotating parts and bearings are also relatively small and, for that reason, they do require repair or replacement occasionally. Although an air motor can be manufactured in a form which is not unusually complicated, it does contain high tolerance working parts which make onthe-spot maintenance difficult to perform, particularly on relatively short notice. That is, if a doctor is performing an operation and the air motor fails, there is normally insufficient time to locate a serviceman, to dismantle the average air motor and return it to operating condition before the patients health could be seriously impaired. Moreover, the kind of skill required for such maintenance is not, as a rule, readily available.

In order to avoid the foregoing problem, it has not been unusual for large hospitals, for example, to have available several of the complete devices, including the handpiece with the motor mounted therein and connected to pneumatic hosing which can be readily attached to a source of air supply and discharge. However, this arrangement may be economically prohibitive for the individual surgeon or a small clinic.

Accordingly, a primary object of this invention is the provision of a surgical device powered by an air motor capable of quick and easy removal from housing means which is attached to air supply and discharge conduits, and which is connectable to tool guiding or protecting means, such as a guide for a drill bit.

A further object of this invention is the provision of a device, as aforesaid, wherein the air motor is in a cartridge form which can be readily removed from the device and inexpensively mailed to a central maintenance establishment for repair and/or replacement of parts, the motor package itself being of a price which makes it reasonable for an individual doctor to have one or two replacements on hand and wherein the replacement procedure is such that the doctor can make the exchange of motors as quickly as he could exchange the entire assembly according to present practice.

A further object of this invention is the provision of a device, as aforesaid, wherein the handpiece manipulated by the surgeon is swivelly connected to the supply and discharge conduits so that the surgeon can rotate the handpiece into any position desired for the purpose of performing an operation without having to overcome the torque created by twisting the conduits.

Other objects and purposes of this invention will become apparent to persons familiar with this type of equipment upon reading the following descriptive material and examining the accompanying drawings, in which:

FIG. 1 is a side elevational view of the pneumatically powered, manually engageable device embodying the invention;

FIG. 2 is an exploded perspective view of said device;

FIG. 3 is a sectional view taken along a line III-III in FIG. 1 and including portions of supply and discharge conduits;

FIG. 4 is a sectional view taken along a line IV-IV in FIG. 3;

FIG. 5 is a sectional view taken along a line VV in FIG. 3 and omitting the outer motor housing;

FIG. 6 is an exploded perspective view of the air motor package;

FIG. 7 is a sectional view taken along a line VIIVII in FIG. 5;

FIG. 8 is a sectional view taken along a line VIII- VIII in FIG. 5;

FIG. 9 is a sectional view taken along a line IX-IX in FIG. 5;

FIG. 10 is a side elevational view of a fragment of the air motor; and

FIG. 11 is a side elevational view of the air motor fragment shown in FIG. 10 but in a different rotational position.

For convenience in description, the terms front," rear and words of similar import will have reference to the right and left ends, respectively, of the device and air motor package as appearing in FIGS. 3 and 5. The terms inner, outer and derivatives thereof will have reference to the geometric center of said instrument and parts thereof.

SUMMARY OF THE INVENTION The objects and purposes of the invention, including those set forth above, have been met by providing an elongated tubular housing defining a cylindrical chamber in which a self-contained air cartridge-type motor is removably disposed. Shaft and coupling means exis removably connectable to surgical tools for rotating.

same at a relatively high speed.

DETAILED DESCRIPTION A pneumatically powered, hand-held device for rotating a surgical tool at a relatively high speed comprises an elongated tubular housing with a central and hollow barrel 11 having a central opening 12 therethrough and

external threads

13 and 14 at the opposite ends thereof. The outer surface of the central barrel is also knurled as at 16 to furnish a nonslip grip for the operators hand. Stop means, such as the annular shoulder 17 is provided internally of the central barrel 11 and defines an opening 18 of less diameter than the opening 12 through the central barrel l1.

A cylindrical nose portion 19 (FIG. 2) extends frontwardly beyond the thread 13 of the central barrel ll. Diametrically opposite sides of the cylindrical nose portion 19 are flattened at 21 and 22 for engagement by a tool, such as a wrench, for purposes of assembling the components of the device 10 discussed hereinbelow.

A cylindrical and hollow shroud 23 has an opening 24 through the center thereof which is internally threaded at one end thereof for threaded engagement with the external threads 13 on the front end of the central barrel 11. A seal ring 26 is provided between the cylindrical shroud 23 and the central barrel 1! to prevent the escape of contaminants from within the central barrel l1 and the cylindrical shroud 19. In this particular embodiment, the external surface of the cylindrical shroud 23 is knurled at 27 to improve manual engagement by the operator.

A cup-shaped end cap 31 has a'cylindrical wall 32 with a pair of flat surfaces33 and 34 (FIG. 1) on opposite sides for engagement by a tool during assembly of the device 10. The internal surface of the cylindrical wall 32 has internal threads 36 adapted to threadedly engage the threads 14 of the central barrel 11. The external surface of the wall 32 is reduced in diameter at the rear end thereof and externally threaded at 37. The end wall 38 of the end cap 31 has a coaxial, internally threaded opening 39 therethrough. A plurality of smooth bore openings 41 (FIG. 4), here four openings, are uniformly spaced around the threaded opening 39.

An externally threaded and hollow nipple 42, having a coaxial opening 43 through it, is threadedly received into the threaded opening 39. A wrench socket 44 is provided within the rear end of the opening 43 for receiving a wrench. Thus, the nipple 42 can be rotated to adjust its position axially of the end cap 31.

A cartridge-type pneumatic motor unit 46 (FIGS. 2 and 5) has a cylindrical casing 47 with a coaxial opening 48 therethrough and an annular flange 49 extending radially inwardly at the front end thereof to define an axial opening 51. A cupshaped bearing retainer 52 has a chamber 53 adapted to receive a bearing 54. The end wall 56 of the bearing retainer 52 has a coaxial opening 4 57 through which themotor shaft 55 can slidably and rotatably extend.

The cup-shaped bearing retainer 52 is received within the cylindrical casing 47 adjacent the forward end thereof so that the outer race 58 of bearing 54 will engage the flange 49. The opening 59 through the inner race 61 is coaxial with the opening 57.

A cylindrical sleeve 62 is received within the cylindrical casing 47 and held against the end wall 56. An eccentric, cylindrical bore 63 is provided through the sleeve 62. The rear end of the sleeve 62 has an axially extending opening 66 (FIG. 5 for receiving an orientation or alignment pin 67.

An elongated groove 68 in the peripheral surface of the sleeve 62 cooperates with the inner surface of the casing 47 to define an inlet passageway. A plurality of radially extending inlet ports, here two inlet ports 69, communicate between the inlet passageway 68 and the opening 63. A second elongated groove 71 (FIG. 11) in the external surface of the sleeve 62 And circumferentially spaced from the inlet passageway 68, defines an outlet passageway which extends more than (FIG. 8) circumferentially of said sleeve. A plurality of radially extending outlet ports 72 communicate between the passageway 71 and the opening 63. The inlet and outlet passageways 68 and 71, respectively, extend from the rearward end of the sleeve 62 to points spaced from the front end of the sleeve.

A rotor 76 comprises a body portion 77 having a plurality of radially opening and lengthwise slots 78 therein. The motor shaft 55 extends axially frontwardly from the body portion 77 and has threads 81 at the frontward end thereof. A coaxial journal 82 is integral with the rear end of the body portion 77.

The rotor 76 is received in the openingor bore 63 in the sleeve 62 with the shaft 55 extending through the opening 59 defined by the inner race 61 of the bearing 54. A spacer 83 encircles the shaft 55 between the inner race 61 of the bearing 54 and the body portion 77, and said spacer 83 is thicker than the wall56 of the bearing retainer 52.

The radial slots 78 in the body portion 77 each slidably receive a thin Micarta, linen base vane 84. Each of the vanes 84 is adapted to be thrown radially outwardly when the rotor 76 is rotated so that each of the vanes 84 will engage the wall of the sleeve 62 defining the opening 63. A cup-shaped bearing retainer 86 has a cylindrical wall 87 and an end wall 88 having a coaxial opening 89 therethrough. The retainer 86 is adapted to house a bearing 92'and locate same so that the opening 93 in the inner race 94 will be coaxial with the cylindrical casing 47 and the opening 89. The journal 82 on the rotor 76 is received into the opening 93 in the inner race 94, so that the rotor 76 is supported within the sleeve 62 for rotation about an axis which is coaxial with the opening 48 in the casing 47. The radial slots 78 open axially through the front and rear ends of the body portion 77, but the vanes 84 are of such length that they freely move with the rotor 76 and without obstruction from the adjacent walls of the bearing retainers S2 and 86.

An axially extending opening 96 is provided in the front face of the bearing retainer 86 to receive the rear of the alignment pin 67. An air seal 97 is positioned within a groove in the rear face of the bearing retainer 86 to close the chamber 91 in which bearing 92 is disposed.

An axial opening 98 is provided in the rear face of the bearing retainer 86 adjacent the periphery thereof and is adapted to receive an alignment pin 99.

The peripheral surface of the bearing retainer 86 has an axially extending groove which cooperates with the wall of the casing 47 to define an inlet passageway 101 (FIG. which is axially aligned with the inlet passageway 68 along the sleeve 62. A longitudinally extending groove in the retainer 86 defines an outlet passageway 102 which is circumferentially spaced from the inlet passageway 101. In this particular embodiment, a rib 103 is centrally located along the passageway 102 to prevent radial movement of the retainer 86.

A cylindrical air distribution member 104 is mounted within the rear end of the motor casing 47 and has an eccentric opening 105 in the front face thereof adapted to receive the rear end of the alignment pin 99. A coaxial opening 106 extends through the air distribution member 104 and is flaired at the rear end 107 thereof. A radial groove 108 (FIGS. 7 and 9) in the front face of the member 104 communicates between the central opening 106 and the inlet passageway 101 in the bearing retainer 86, which is aligned with the inlet passageway 68 in the sleeve 62. A groove 111 in the peripheral surface of the air distribution member 104 communicates with the passageway 102, hence with the passageway 71.

After all of the components described hereinabove are placed within the casing 47 of the pneumatic motor assembly 46, the rear end of the casing 47 may be crimped as at 112 to lock the entire assembly within the casing 47.

If desired, a shaft extension 113 (FIG. 5) having an internally threaded opening 114 in the rear end thereof may be threadedly attached to the shaft 55 on the rotor 76. The shaft extension 113 may be secured so that the rear end thereof abuts the forward edge of the inner race 61 of the bearing 54. A pin 116 is received in a transverse opening in the front end of the shaft for coupling same to a tool 117, such as a drill bit.

The pneumatic motor assembly 46 is slidably received into the opening 12 in the central barred 1 1 with the shaft extension 113 projecting into the cylindrical shroud 23. A tool 117 having a shank 118 with a bifurcated end member 119 is adapted to engage the pin 116 at the front end of the shaft extension 113, said pin being received between the legs of the bifurcated end member 119.

The nipple 42 can be adjusted axially of the end cap 31 to place the forward end thereof into engagement with the flaired wall 107 of the air distribution member 104. The shoulder 17 in the central barrel 11 will obstruct a forward movement of the pneumatic motor assembly 46 within the central barrel 11, and the nipple 42 will prevent the rearward movement thereof. Further, the nipple 42 can be adapted to tightly engage the flaired wall 107 of the air distribution member 105 to prevent the escape of air therebetween.

An outer swivel adapter 121 (FIGS. 1 and 2) is threadedly engaged at 122 with the rear end of the end cap 31 and has an annular flange 123 extending radially inwardly to define an opening 126. The flange 123 is spaced from the wall 38 of the end cap 31 to define a clearance 124 therebetween. A pair of diametrically opposed flat surfaces 125 are provided in the periphery of the swivel adapter 121 for engagement by a tool to assist in the assembly of the adapter.

An outer hose connector 127 comprises a generally cylindrical sleeve 128 having a coaxial opening 129 and a radially outwardly extending flange 131 on the front end thereof. The flange 131 is positioned within the clearance 124 between the end wall 38 of the end cap .31 and the annular flange 123 of the swivel adapter 121. The radial dimension of the flange 131 is greater than the diameter of the opening 126, and the hose connector can rotate 360 relative to the adapter 121. One end of a flexible hose 132 is telescoped over the sleeve 128 and secured thereto by an annular hose clamp 133. The sleeve 128 has an annular groove 134 into which the hose 132 is pressed by the clamp 133 to resist disengagement of the sleeve 128 from the hose.

An inner swivel adapter 136 is threadedly engaged at 138 with the rear end of the nipple 42 and extends rearwardly therefrom. The swivel adapter 136 has a rear portion of reduced inside diameter defining a shoulder 142 which is spaced from the rear end of the nipple 42 to provide a clearance 141. A pair of flat surfaces 137 are provided on opposite sides of the swivel adapter 136 for engagement by a tool to assist in the assembly thereof.

An inner hose connector 143 comprises a generally cylindrical sleeve 144 having a coaxial opening 146. A radially outwardly extending flange 147, which is provided at the front end of connector 143, is received in the clearance 141. The radial dimension of the flange 147 is greater than the diameter of the opening 142 in the swivel adapter 136, and the hose connector 143 can rotate 360 relative to the adapter 136.

A flexible hose 148, which is disposed within and substantially coextensive with the hose 132, has one end telescoped on the hose connector 143 and clamped thereto by any convenient clamping means, such as a coiled spring 149.

OPERATION Although the operation of the hand-held device 10 will be understood by skilled persons from the foregoing description, a summary of the operation is now given for convenience.

Air under pressure may be supplied from any convenient source which is connected to the hose 148. The air passes through the opening 146 of the hose connector 143 and the opening 43 through the nipple 42 into the opening 106 in the air distribution member 104. This air moves radially outwardly through the passageway 108 and thence along the inlet passageways 101 and 68 (FIG. 10) from which it moves through the inlet ports 69 (FIG. 8) into the opening 63 in the sleeve 62 to engage the vanes 84 of the rotor 76, thereby effecting a clockwise rotation (FIG. 8) of the rotor 76. That is, due to the eccentricity of the rotor 76, the air under pressure will urge the rotor to move in a direction which will increase the volume of the space between a given pair of vanes after the air has moved into such space.

The rotor can rotate at speeds in excess of 20,000 rpm, and such rotation will cause the vanes 84 to be thrown outwardly due to centrifugal force so as to engage the wall of the opening 63 in a known manner. The vanes 84 will slide radially within the slot 78 to accommodate the eccentricity of the rotor relative to the bore 63 of the sleeve 62.

The air which entered through ports 69 discharges from the bore 63 through the outlet ports 72 (FIGS. 8

and 11) and then travels rearwardly of the sleeve 62 along the outlet passageways 71, 102 and 111 into the zone between the rear end of the pneumatic motor unit 46 and the wall 38 of the end cap 31. The air will then pass through the smooth bore openings 41, the opening 129 in the hose connector 127 and thence into the return or outer hose 132.

A tool 1 17 is connected to the shaft extension 1 13 for rotation by the motor unit 46. While the tool 117 is rotated in this embodiment, means may be provided to convert the rotary output of the motor unit 46 into a reciprocal motion, such as is disclosed in a copending application entitled Power Osteotome and assigned to the Assignee of this application.

If, for any reason, the pneumatic motor unit 46 fails to function properly, the operator can quickly and easily remove the motor unit 46 by unscrewing the end cap 3l from the central barrel 11, after which the pneumatic cartridge-type motor unit 46 slides out of the central barrel 11. A replacement pneumatic cartridge-type motor unit 46 is inserted into the barrel 11 so that the front end thereof engages the shoulder 17, and the end cap 31 is then replaced on the rear end of the central barrel 11 and tightened so that the nipple 42 again tightly engages the rear side of the air distribution member 104.

Although a particular preferred embodiment of 'the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a pneumatic-powered, hand-held device for rotatin g a surgical tool at a relatively high speed, the combination comprising:

elongated tubular housing means having radially inwardly projecting shoulder means near one end thereof and facing the other end thereof;

a cylindrical, self-contained, cartridge-type pneumatic motor unit removably but snugly and slidably positioned in said housing means, one end of said motor unit being disposed in engagement with said shoulder means;

said cartridge-type pneumatic motor unit including inlet and outlet passageways formed therein adjacent said other end of said unit for enabling air to be supplied thereto and exhausted therefrom;

end cap means removably secured to the other end of said housing and disposed in engagement with said other end of said motor unit for maintaining said unit against said shoulder means, said end cap means including inlet and outlet openings therein disposed in communication with said inlet and outlet passageways, respectively;

flexible inlet conduit means for supplying air to said inlet opening;

coupling means swivelly connected between said endcap means and the adjacent end of said inlet conduit means for permitting said housing means to rotate relative to said inlet conduit means while maintaining said inlet conduit means in flow communication with said inlet opening, said coupling means connecting the adjacent end of said conduit means to said end cap means in substantially coaxial alignment with the longitudinally extending axis of said housing means;

whereby removal of said end cap means from said housing means permits said motor unit to be easily slidably removed from said housing means as an assembled one-piece unit.

2. A device according to claim 1, wherein said motor unit includes an axially elongated sleeve-like casing structure having an elongated eccentric bore formed therein, bladed rotor means coaxially rotatably supported within said casing structure and having blades disposed for sliding sealing engagement with the wall of said eccentric bore, and means coacting with the opposite axial end of said rotor means for retaining same within said casing structure, whereby said casing structure and the rotor contained therein is removable from said housing means as a unit.

3. A device according to claim 1, wherein said end cap means has a hollow pipe member threadedly supported therein and extending therethrough in substantial coaxial alignment with said housing means, said pipe member having a bore therethrough defining said inlet opening and said other end of said motor unit having said inlet passageway terminating in an inlet port located in the axial end of said motor unit substantially on the central longitudinal axis thereof, whereby said inlet port is substantially aligned with and abuttingly sealingly engaged by one end of said pipe member when said end cap means is mounted on said housing means, the threaded mounting of said pipe member on said end cap means permitting same to be axially adjusted relative to said end cap means for causing the end of said pipe member to abuttingly sealingly engage said motor unit in surrounding relationship to said inlet port.

4. A device according to claim 1, further including flexible outlet conduit means for discharging air from said outlet opening, said inlet and outlet conduit means being disposed one within the other in substantially concentric relationship to define a flow path therebetween, and said coupling means being swivelly connected between said end cap means and the adjacent end of said outlet conduit means for permitting said housing means to rotate relative to said outlet conduit means while maintaining said outlet conduit means in flow communication with said outlet opening.

5. A device according to claim 4, wherein said coupling means includes a first swivel-type coupling structure connected between said inlet conduit means and said end cap means for permitting relative rotation therebetween, and said coupling means including a second swivel-type coupling structure connected between said outlet conduit means and said end cap means for permitting relative rotation therebetween, whereby said inlet and outlet conduit means can rotate relative to one another and relative to said housing means.

6. In a pneumatically powered, hand-held device for rotation a surgical tool at a relatively high speed, the combination comprising:

a cylindrical, self-contained, cartridge-type pneumatic motor unit removable but snugly and slidably positioned in said housing means, one end of said motor unit being disposed in engagement with said shoulder means, said motor unit including:

l. elongated, cylindrical casing means slidably and snugly receivable into said tubular housing means for engagement at one end with said shoulder means;

2. bladed rotor means coaxially disposed within said casing means and having fixedly connected shaft means extending through and beyond the said end of said casing means adjacent said shoulder means;

3. bearing means rotatably supporting said rotor means coaxially within said casing means;

4. sleeve means snugly and removably disposed within said casing means, said sleeve means having an eccentric bore encircling said rotor means and having axially extending, inlet and outlet passageways spaced circumferentially from each other, said sleeve means having radially extending inlet and outlet ports communicating with said inlet and outlet passageways, respectively, and with the bore of said sleeve; and

removable end cap means fixedly secured upon the other end of said housing means for urging said casing means snugly against said shoulder means and for fixedly axially retaining said casing means between said shoulder means and said end cap means, said end cap means having inlet and outlet openings therethrough and means for effecting communication of said inlet and outlet openings with said inlet and outlet passageways, respectively.

7. A device according to claim 6 including inlet and outlet conduits, the inlet conduit being loosely disposed within and substantially coextensive with the outlet conduit to provide an outlet passage lengthwise thereof and therebetween;

first coupling means swivelly connecting said outlet conduit to said end cap means, whereby said outlet passage communicates with said outlet opening; and

second coupling means swivelly connecting said inlet conduit to said cap means for communication with said inlet opening, whereby said conduits are freely rotatable with respect to said tubular housing means and said end cap means.

8. A device according to claim 1, wherein said coupling means includes a first swivel-type coupling structure connected between said inlet conduit means and said end cap means for permitting relative rotation therebetween, and said coupling means including a second swivel-type coupling structure connected between said outlet conduit means and said end cap means for permitting relative rotation therebetween whereby said inlet and outlet conduit means can rotate relative to one another and relative to said housing means.

9. A device according to claim 1, wherein said cylindrical casing means is open at both ends and has a radially inwardly projecting stop means near said one end thereof, and said bearing means including bearings supporting the opposite ends of said rotor means within said casing means, one of said bearings engaging said stop means.

10. A device according to claim 9 including second shaft means integral and coaxial with said rotor means at the other end thereof;

wherein said bearing means includes a pair of bearings encircling said first mentioned and said second shaft means and a pair of bearing retainers encircling said bearings and snugly embracing the opposite ends of said sleeve means, said bearings and said retainers being disposed in said casing means adjacent the opposite ends thereof; and

end plug means disposed and retained within said casing means adjacent said other end thereof and bearing against the adjacent bearing retainer, said end cap means being adapted to engage said plug means whereby said plug means, said bearing retainers and said sleeve means are held under compression between said cap means and said stop means.

11. A structure according to claim 10 wherein said casing means extends slightly beyond the exposed end of said plug means, said extended end of said casing means being staked inwardly over said exposed end;

coupling means connected to said first mentioned shaft means for releasable connection to tool means; and

cylindrical shroud means releasably mounted upon the one end of said housing means and projecting beyond the free end of said tool coupling means.

Patent No. '1 724 5:9 Dated May 22. 1973 Inventor( .Tnh-n w ia It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 8, line 16; after "rotor insert ---means--.

Column 9, line 44 insert after "Claim 1",

further including flexible outlet conduit means for discharging air ffrom said outlet opening, and'.

Column 10, line 9; change "Claim 1'' to -Claim 6-,-.

Signed and sealed this 19th day of March 19714..

(SEAL) Attest:

EDWARD M, FLETCHER, JR. Ca MARSHALL DANN Attesting Officer Commissioner of Patents FORM Po-1050 (10-69) uscoMM-Dc 60376-P69 U.5. GOVERNM ENT PRINTING OFFICE: 1969 0-366-334

Claims

1. In a pneumatic-powered, hand-held device for rotating a surgical tool at a relatively high speed, the combination comprising: elongated tubular housing means having radially inwardly projecting shoulder means near one end thereof and facing the other end thereof; a cylindrical, self-contained, cartridge-type pneumatic motor unit removably but snugly and slidably positioned in said housing means, one end of said motor unit being disposed in engagement with said shoulder means; said cartridge-type pneumatic motor unit including inlet and outlet passageways formed therein adjacent said other end of said unit for enabling air to be supplied thereto and exhausted therefrom; end cap means removably secured to the other end of said housiNg and disposed in engagement with said other end of said motor unit for maintaining said unit against said shoulder means, said end cap means including inlet and outlet openings therein disposed in communication with said inlet and outlet passageways, respectively; flexible inlet conduit means for supplying air to said inlet opening; coupling means swivelly connected between said end cap means and the adjacent end of said inlet conduit means for permitting said housing means to rotate relative to said inlet conduit means while maintaining said inlet conduit means in flow communication with said inlet opening, said coupling means connecting the adjacent end of said conduit means to said end cap means in substantially coaxial alignment with the longitudinally extending axis of said housing means; whereby removal of said end cap means from said housing means permits said motor unit to be easily slidably removed from said housing means as an assembled one-piece unit.

4. sleeve means snugly and removably disposed within said casing means, said sleeve means having an eccentric bore encircling said rotor means and having axially extending, inlet and outlet passageways spaced circumferentially from each other, said sleeve means having radially extending inlet and outlet ports communicating with said inlet and outlet passageways, respectively, and with the bore of said sleeve; and removable end cap means fixedly secured upon the other end of said housing means for urging said casing means snugly against said shoulder means and for fixedly axially retaining said casing means between said shoulder means and said end cap means, said end cap means having inlet and outlet openings therethrough and means for effecting communication of said inlet and outlet openings with said inlet and outlet passageways, respectively.

6. In a pneumatically powered, hand-held device for rotation a surgical tool at a relatively high speed, the combination comprising: elongated tubular housing means having radially inwardly projecting shoulder means near one end thereof and facing the other end thereof; a cylindrical, self-contained, cartridge-type pneumatic motor unit removable but snugly and slidably positioned in said housing means, one end of said motor unit being disposeD in engagement with said shoulder means, said motor unit including:

7. A device according to claim 6 including inlet and outlet conduits, the inlet conduit being loosely disposed within and substantially coextensive with the outlet conduit to provide an outlet passage lengthwise thereof and therebetween; first coupling means swivelly connecting said outlet conduit to said end cap means, whereby said outlet passage communicates with said outlet opening; and second coupling means swivelly connecting said inlet conduit to said cap means for communication with said inlet opening, whereby said conduits are freely rotatable with respect to said tubular housing means and said end cap means.

10. A device according to claim 9 including second shaft means integral and coaxial with said rotor means at the other end thereof; wherein said bearing means includes a pair of bearings encircling said first mentioned and said second shaft means and a pair of bearing retainers encircling said bearings and snugly embracing the opposite ends of said sleeve means, said bearings and said retainers being disposed in said casing means adjacent the opposite ends thereof; and end plug means disposed and retained within said casing means adjacent said other end thereof and bearing against the adjacent bearing retainer, said end cap means being adapted to engage said plug means whereby said plug means, said bearing retainers and said sleeve means are held under compression between said cap means and said stop means.

11. A structure according to claim 10 wherein said casing means extends slightly beyond the exposed end of said plug means, said extended end of said casing means being staked inwardly over said exposed end; coupling means connected to said first mentioned shaft means for releasable connectioN to tool means; and cylindrical shroud means releasably mounted upon the one end of said housing means and projecting beyond the free end of said tool coupling means.