US3832088A

US3832088A - Modular pneumatic surgical drill

Info

Publication number: US3832088A
Application number: US00181999A
Authority: US
Inventors: H Cromie
Original assignee: Baxter Laboratories Inc
Current assignee: Baxter International Inc
Priority date: 1971-09-20
Filing date: 1971-09-20
Publication date: 1974-08-27
Anticipated expiration: 1991-08-27
Also published as: CH556165A; JPS4837982A; GB1390979A; ES406869A1; IT967413B; DE2245578A1; BE788347A; FR2154109A5; CA992772A

Abstract

A pneumatically driven turbine type drill has a modular casing that provides an air supply passage leading from a rear inlet and including an annular chamber leading to a front annular entry to the turbine and that provides an air exhaust passage leading from a sump at the rear of the turbine through a straight bore to a rear exit.

Description

United States Patent [191 Cromie [11] 3,832,088 [451 Aug. 27, 1974 1 MODULAR PNEUMATIC SURGICAL DRILL [75] Inventor: Harry W. Cromie, Pittsburgh, Pa.

[73] Assignee: Baxter Laboratories, Inc., Morton Grove, Ill.

[22] Filed: Sept. 20, 1971 [21] Appl. No.: 181,999

[52] US. Cl 415/199 R, 32/26, 415/503 [51] Int. Cl A6lc 1/05, F0ld 1/10, A6lb 17/32 [58] Field of Search 415/502, 503, 150, 199.;

[56] References Cited UNITED STATES PATENTS 4/1952 YOst 175/100 4/1964 DeGroff ..32/26 Mothre 415/502 3,695,367 10/1972 Catterfeld et a1 415/503 3,707,336 12/1972 Theis et al. 415/503 3,709,630 l/1973 Pohl et a1 415/503 Primary Examiner--Al1an D. Herrmann Attorney, Agent, or FirmJ. Patrick Cagney; W. Garrettson Ellis [57] ABSTRACT A pneumatically driven turbine type drill has a modular casing that provides an air supply passage leading from a rear inlet and including an annular chamber leading to a front annular entry to the turbine and that provides an air exhaust passage leading from a sump at the rear of the turbine through a straight bore to a rear exit.

11 Claim, 3 Drawing Figures MODULAR PNEUMATIC SURGICAL DRILL BACKGROUND OF THE INVENTION This invention relates to pneumatically actuated surgical drills having a turbine-type drive and, more particularly, is concerned with a drill arrangement that is more compact, more efficient and easier to manufacture than the prior art drills.

Many of the prior art surgical drills of the turbinepowered type are arranged to vent the spent air at the front of the drill. This is objectionable because front venting will dry out the living tissues against which the surgical drill is working. The back venting types of sur-' gical drills are known for avoiding this difficulty but such drills utilize forwardly moving air to power the turbine and require the exhaust air to traverse a 180 turn for back venting. Substantial back pressures occasioned by the 180 turn reduce thepower of the drill.

In addition, the prior art drill constructions utilize more complicated housing sleeves and transverse porting together with intricate internal flow channels that SUMMARY OF THE INVENTION The present invention provides a pneumatically actuated surgical drill that overcomes the above-noted disadvantages of the prior art drills. In the embodiment disclosed herein, a surgical drill of the turbine-operated type is provided with a unique back-venting air passage network which leads forwardly of the turbine to drive the turbine with rearwardly travelling air and exists through a low back pressure exhaust path. In addition, the invention provides a modular casing arrangement wherein complex air flow passages can readily be drilled thereby facilitating mass production and reducing manufacturing costs. The air flow passage arrangement is controlled by an in-line valve contoured to facilitate variable speed control in accordance with the position of a rearwardly shiftable slidable trigger. The trigger can be shifted forwardly to apply braking action on the turbine spindle and/or to control release and gripping of a front mounted collet structure on a tool bit that is to be in the drill.

Other features and advantages of the invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which show structure embodying preferred features of the present invention and the principles thereof, and what is now considered to be the best mode in which to apply these principles.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings forming a part of the specification, and in which like numerals are employed to designate like parts throughout the same:

FIG. 1 is a lengthwise sectional view of the modular surgical drill constructed in accordance with this invention;

FIG. 2 is an enlarged transverse sectional view taken on the line 2--2 of FIG. 1; and

FIG. 3 is a fragmentary lengthwise section taken as indicated on the line 3--3 of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now to the drawings and particularly to FIG. 1 thereof, a pneumatically driven surgical drill is illustrated as including a modular casing assembly designated generally at MC and including a turbine housing 10, a trigger section 11, a valve section 12, a valve cylinder section 13, and an end connection head section 14. Each of the sections 11 through 13 is of right circular configuration and is machined with accurately fitting flat end faces and lengthwise extending bolt passages and air channels for assembly in stacked axial alignment in successive end to end contacting relation to be secured to the rear of the turbine section by elongated bolts B (see FIGS. 2 and 3) that nest in countersunk relation in the valvecylinder section 13 and anchor in tapped holes H provided at the rear of the turbine housing l0. The connector head section 14 is threaded onto the rear end of the valve cylinder section 13 to mask the bolts B and is provided with an inlet fitting 15 for attachment to a source of pressurized air (not shown). The end face of the head section 14 is provided with rearwardly directed air exhaust port 14? for rearward discharge of the spent air. I

A turbine assembly located within the turbine section 10 includes a rotor sleeve 16 having a drive spindle l7 slidably mounted therein in splined or keyed engagement to rotate in unison with the rotor sleeve while accommodating axial shifting of the spindle 17. A three stage turbine arrangement is illustrated as including front, center and rear rotary

turbine blade assemblies

18F, 18C and 18R separated by stationary turbine blade assemblies 19 and secured on the rotor shaft by a lock nut N.

The rotor sleeve 16 has an enlarged diameter integral front extension 16F that is threadedly connected to a stepped diameter chuck 20 to define a chamber 20C for a coil bias spring 205 that encircles the forwardly extending portion of the drive spindle 17. The spindle l7 terminates in an integral front collet structure 17C normally biased inwardly into wedging engagement with the chuck 20 for tightly clamping a tool bit (not shown).

The turbine housing includes a rear attachment section 21 in which the assembly bolts B are anchored. The attachment section 21 has an externally threaded portion screwed into the rear end of the main turbine housing shell 22 which has an in-turned forward flange 22F securely supporting a chuck housing 23.

The forward end of the attachment section 21 has a forwardly projecting annular ring 21R serving to accurately position a stationary support sleeve 24 that carries the stationary turbine blade assemblies 19. A bearing assembly 25 is mounted between the chuck 20 and the chuck housing 23. A bearing assembly 26 is mounted between the rotor sleeve 16 and the rear of the chuck housing 23 and a bearing assembly 27 is mounted between the rear of the rotor sleeve 16 and the rearmost stationary turbine blade assembly 19.

An elongated annular air supply passage 28 is defined between stationary sleeve 24 and the main housing shell 22 to lead forwardly completely beyond the front turbine blade assembly 18F and open into an annular front region to direct the air rearwardly in substantially unifonnly distributed relation (see arrow A in FIG. 1') into the front turbine blade assembly for rearward passage through the turbine. Thus, in operation, the pressurized air impartsrotation to the

rotary turbine blades

18F, 18C and 18R, the rotor sleeve 16, the drive spindle 17 and the chuck 20, while the main shell 22 of the turbine housing, the stationary sleeve 24 and the chuck housing 23 remain stationary.

An air inlet passage 14A is shown leading axially through the rear head section 14 and includes a region 13A leading into the valve chamber section 13 which includes an eccentrically located enlarged passage 13C for a return spring 29. The air inlet passage then leads through a valve seat chamber 12C which has a jogged passage region 12A (see FIG. 3) communicating with a through bore 11A provided in the trigger section 11. The triger section 11 also has a valve guide passage [IV for an actuating rod 30 which is formed integrally with a valve 31 that has a tapered flow control surface to accommodate variable air flow control. The through bore 11A of the trigger section communicates with an in-line bore portion 21A provided at the rear of the attachment section. The in-line bore portion merges with an oblique bore portion 218 that opens into the circular forwardly extending air supply passage 28 to leas the incoming air around the front of the turbine for rearward flow through the turbine.

The air exhaust passage includes an enlarged sump chamber E of generally frusto-conical form in the front end of the attachment section to face the rear end of the turbine section. The sump 21E communicates in substantially uniformly distributed relation with the rear region of the turbine means and communicates with an angled bore 21E leading through the attachment section 21. The remainder of the exhaust passage consists of aligned bores 11E, 12E and 1312, respectively, provided in the trigger section 11, valve seat section 12 and valve chamber section 13. Since the head section 14 is threadedly mounted, it is provided with an annular exhaust chamber region 14E so that there is communication with the exhaust outlet of the valve chamber section 13 for any rotary position of the head section 14. The annular exhaust chamber 14E then leads through the plurality of rearwardly directed vent passages 14F to direct the spent air away from the living tissue to which the drill is being applied.

A hand trigger 32 is shown slidably mounted upon the main shell 22 and it includes an integral connector stem 32S projecting transversely into a generally rectangularly shaped socket 115 that is provided in the trigger section. The connector stern 325 is secured by a lock pin 32F to an axial rod 33 which is slidably mounted in aligned guide bores provided in the trigger section and the attachment section.

When the trigger 32 is shifted to its full forward position, the slide rod 33 abuts and shifts the drive spindle 17 to project the collet structure 17C forwardly of the chuck and allow a tool bit to be inserted therein. Forward movement of the collet 17C is resisted by the return spring 205 contained in the chuck. Upon release of the trigger 32, the return spring 208 restores the spindle 17 to its operating position and causes the collet 17C to be wedged tightly in the chuck 20 for holding the tool bit.

When the trigger 32 is shifted rearwardly, the valve 31 is progressively raised away from its valve seat ring 31R. The effective size of the port between the valve 31 and valve seat ring depends upon the extent of rearward travel imparted to the trigger. Correspondingly, the flow rate of the incoming air is regulated inaccordance with the travel imparted to the valve by the trigger so that a variable speed effect is achieved. During use of the tool, the trigger 32 may be advanced partly fowardly whereupon the valve return spring 29 restores the valve shutting off air supply. In addition, the guide rod 33 establishes contact with the rear end of the spindle 17 to produce a friction braking action for limiting drill rotation.

From the drawings and the foregoing disclosure, it will be noted that the air follows a reversal path as indicated by the arrows A at the front of the turbine blade assemblies and undergoes expansion during rearward flow through the successive sets of turbine blades to drive the rotary mechanisms. The spent air exiting from the rear turbine blade assembly 18R expands into an enlarged sump 10E that connects straight to the rear of the casing MC through aligned

exit bores

21E, 11E, 12E and 1315 to allow exhaust of the air at minimum back pressure. This arrangement maximizes the power developed by the drill by minimizing the presence of restrictions in the flow path of the high velocity, high volume expanded air flow.

It should also be noted that the modular casing con struction allows the various bores and chambers to be drilled with accurate high volume production techniques. Each of the casing sections 11 to 14 and 21 is circular and has end faces for easy axial and rotary alignment. The bores are machinable from the end face to allow for jogs and angles in the passage profile. The common set of bolts B holds these sections in predetermined registered alignment.

Thus, while preferred constructional features of the invention are embodied in the structure illustrated herein, it is to be understood that changes and variations may be made by those skilled in the artwithout departing from the spirit and scope of the appended claims.

What is claimed is:

1. in a pneumatically driven turbine type surgical drill that includes casing means having turbine means rotatably mounted therein, releasable tool holding means operable by said turbine means, and trigger means for controlling supply of compressed air to said turbine means, the improvement wherein said casing means has an air flow passage network including an air inlet located rearwardly of said turbine means, an air supply passage leading from said inlet to a front region of said turbine'means for rearward flow through said turbine means to impart rotation thereto and an air exhaust passage leading from a rear region of the turbine means to an exit located rearwardly of said turbine means.

2. in a drill as defined in claim 1 and wherein said casing means includes concentric telescoping sleeves encircling said turbine means and defining an elongated annular air supply passage region for directing incoming air to an annular front region of said turbine means for directing the air rearwardly in substantially uniformly distributed relation into the turbine means.

3. in a drill as defined in claim 1 and wherein said exhaust passage includes a sump region communicating in substantially uniformly distributed relation with the rear region of the turbine means, and a substantially straight bore communicating with the sump region and extending through the casing means to exhaust through said exit at the extreme rear region of said casing means.

4. In a drill as defined in claim 3 and wherein said casing means includes concentric telescoping sleeves encircling said turbine means and defining an elongated annular air supply passage region for directing incoming air to an annular front region of said turbine means for directing the air rearwardly in substantially uniformly distributed relation into the turbine means.

5. In a pneumatically driven turbine type surgical drill that includes casing means having turbine means rotatably mounted therein, releasable tool holding means operable by said turbine means, and trigger means for controlling supply of compressed air to said turbine means, the improvement wherein said casing means comprises a modular casing assembly that includes a turbine housing having a rear attachment section, a trigger section, a valve section and a valve cylinder section in successive axial alignment, each of said sections having a separate endwise opening air supply passage portion and a separate endwise opening air exhaust passage portion, and means securing said sections in end to end contacting relationship wherein the air supply passage portions are in successive registry to define an air supply passage and the air passage portions are in successive registry to define an air exhaust passage. I

6. In a drill as defined in claim 5 and wherein said turbine housing includes concentric telescoping sleeves encircling said turbine means and defining an elongated annular air supply passage region for directing incoming air to an annular front region of said turbine means for directing the air rearwardly in substantially uniformly distributed relation into the turbine means.

7. In a drill as defined in claim 6 and wherein said exhaust passage includes a sump region communicating in substantially uniformly distributed relation with the rear region of the turbine means, and a substantially straight bore communicating with the sump region and extending through the casing means to exhaust through said exit at the extreme rear region of said casing means.

8. In a drill as defined in claim 5 and wherein said valve section includes an air supply passage portion having an eccentric valve chamber region opening through its rear face and a jogged passage region opening through its front face, said trigger section includes an eccentric guide bore opening through its rear face and communicating with said valve chamber region to receive a valve actuating rod, an axial guide bore to receive a slide rod for actuating the releasable tool holding means and a transversely opening socket intersecting said eccentric guide bore and said axial guide bore, said trigger means having a stem portion projecting through said socket to engage the valve actuating rod and the slide rod for controlling fore and aft shifting thereof. 7 I

9. In a drill as defined in claim 1 and wherein said casing means comprises a modular casing assembly that includes a turbine housing having a rear attachment section and at least one additional section for supporting said trigger means and for supporting valve means controlled by said trigger means, each of said sections having a separate endwise opening air supply passage portion and a separate endwise opening air exhaust passage portion, and means securing said sections in end-to-end contacting relationship wherein the air supply passage portions are in successive registry to define said air supply passage and the air exhaust passage portions are in successive registry to define said air exhaust passage.

10. A pneumatic turbine powered surgical motor apparatus for rotating a medical instrument comprising, in combination, an elongated housing having a longitudinal axis, an input end and an output end, a shaft rotatably mounted in said housing concentric with said axis and projecting from said output end adapted to drive a cutting instrument, a pressurized gas connection and an exhaust gas connection defined on said housing at said input end, an axial flow turbine having a rotor rotatably mounted in said housing concentric thereto and drivingly connected to said shaft, said turbine having an inlet disposed toward said housing output end and an exit disposed toward said housing input end, first passage means longitudinally defined in said housing concentrically extending about the periphery of said turbine and communicating with said pressurized gas connection and said turbine inlet, and second passage means defined in said housing communicating with said exhaust gas connection and said turbine exit whereby pressurized gas entering said pressurized gas connection and first passage flows toward said housing output end to said turbine inlet, enters said turbine inlet and reverses its direction of flow to flow through said turbine toward said housing input end and from said turbine exit to said exhaust gas connection.

11. In a pneumatic turbine powered surgical motor apparatus as in claim 10 wherein said first passage means comprises an annular chamber concentrically disposed about said turbine and said second passage means comprises a plurality of passages axially defined in said housing extending between said turbine exit and said exhaust gas connection.

Claims

1. In a pneumatically driven turbine type surgical drill that includes casing means having turbine means rotatably mounted therein, releasable tool holding means operable by said turbine means, and trigger means for controlling supply of compressed air to said turbine means, the improvement wherein said casing means has an air flow passage network including an air inlet located rearwardly of said turbine means, an air supply passage leading from said inlet to a front region of said turbine means for rearward flow through said turbine means to impart rotation thereto and an air exhaust passage leading from a rear region of the turbine means to an exit located rearwardly of said turbine means.

5. In a pneumatically driven turbine type surgical drill that includes casing means having turbine means rotatably mounted therein, releasable tool holding means operable by said turbine means, and trigger means for controlling supply of compressed air to said turbine means, the improvement wherein said casing means comprises a modular casing assembly that includes a turbine housing having a rear attachment section, a trigger section, a valve section and a valve cylinder section in successive axial alignment, each of said sections having a separate endwise opening air supply passage portion and a separate endwise opening air exhaust passage portion, and means securing said sections in end to end contacting relationship wherein the air supply passage portions are in successive registry to define an air supply passage and the air passage portions are in successive registry to define an air exhaust passage.

8. In a drill as defined in claim 5 and wherein said valve section includes an air supply passage portion having an eccentric valve chamber region opening through its rear face and a jogged passage region opening through its front face, said trigger section includes an eccentric guide bore opening through its rear face and communicating with said valve chamber region to receive a valve actuating rod, an axial guide bore to receive a slide rod for actuating the releasable tool holding means and a transversely opening socket intersecting said eccentric guide bore and said axial guide bore, said trigger means having a stem portion projecting through said socket to engage the valve actuating rod and the slide rod for controlling fore and aft shifting thereof.