Fluid Operated Surgical Tool

Abstract

A fluid operated surgical tool having a body to which variously configured object-engaging elements may be removably attached for gripping, cutting or perforating bone, tissue or other structures. Housed within the body is an assembly, responsive to fluids under pressure, for operating the object-engaging elements. A fluid regulating valve assembly is provided for precisely controlling the flow of fluids to the pressure-responsive assembly, so that the surgeon may deftly and accurately control the movement of the object-engaging elements. The fluid regulating valve assembly comprises a valve seat through which fluid flows to the pressure-responsive assembly, a valve, an operator control for disengaging the valve from the valve seat, and an automatic pressure-balancing mechanism for moving the valve seat into reengagement with the valve to stop the flow of fluid therethrough when pressures acting on the pressure-responsive assembly reach predetermined levels.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to fluid operated tools and more particularly to hand-held pneumatically operated surgical tools for use in gripping, cutting or perforating bone, tissue and other structures.

2. Description of the Prior Art

A large family of surgical instruments generally classified as forceps or rongeurs has been developed to perform various gripping, holding, cutting, chipping or perforating operations on bone and tissue. Characteristically, these instruments have pivotally connected handle members which are adapted to be squeezed together by the surgeon with one hand to bring variously shaped and configured opposing gripping or cutting jaw elements into operational juxtaposition. The compressive forces which are required to be generated in the use of these instruments during surgery range from extremely slight gripping pressures for holding a tissue or small bones to very large pressures for cutting, chipping or perforating bone.

Power assist forceps or rongeurs are virtually unknown in the prior art. When cutting or perforating bone the surgeon has been forced to rely solely on the strentgh in his hands and arms to generate the considerable compressive forces required. This is highly disadvantageous since undue exertion by the surgeon during the cutting or perforating of bone can cause severe muscle fatigue and concomitant unsteadiness and lessened sensitivity of touch and feel. Additionally, undue effort required to incise tissue or bone may cause irreparable harm to important surrounding body structures.

Although undoubtedly recognizing the drawbacks of surgical instruments of traditional design for cutting and perforating bone, the medical profession has nevertheless been highly cautious in accepting for surgical use any type of power-operated instrument. This reluctance stems in large part from the failure of designers of such instruments to adequately satisfy the high quality standards for surgical instruments demanded by surgical practitioners. Among these requirements are precise controllability, strength of construction, versatility of operation, simplicity of design, reliability of operation, and ease of sterilization. The surgeon also demands that the instrument be of such form and size as to permit deft and comfortable manipulation.

Applicant is familiar with the following patents:

Patentee Patent No. J. A. Heidbrink 1,543,847 W. D. Beezley, et al. 2,599,888 R. S. Martin 2,688,321 E. C. Carlson 2,984,241 M. S. DeGroff 3,128,079

In the development of the novel and unique tool as described herein, I have been successful in accommodating each of these stringent and diverse requirements. To achieve maximum reliability and safety of operation, I have chosen to drive the device by fluid pressure. In this way the drawbacks of electrically powered surgical tools such as arcing, motor failure and possible short-circuiting have been avoided. To achieve precise controllability, I have devised a highly novel and unique automatic pressure-balancing valving system for regulating the flow of operating fluids to the tool. This unique regulating system, which is conveniently housed within a hand-held pistol grip-type body, allows the surgeon to precisely regulate both the speed of relative movement of the object-engaging elements of the device as well as the compressive forces exerted thereby. Due to the novel balancing feature of the valving means, the relative movement of the operating elements directly corresponds to the movement of the surgeon's finger on the operating trigger of the device. This provides the controllability and "feel" which is so vital in surgical application and which is typically absent in power-operated surgical devices. To accommodate easy sterilization, the object-engaging members are easily and quickly removable from the body portion of the tool for either chemical or high-temperature sterilization.

SUMMARY OF THE INVENTION

The previously mentioned disadvantages of prior are power assist surgical instruments have been largely overcome by the unique construction of the tool of my invention, an object of which is to provide a tool for gripping, cutting or perforating various types of materials which is operable by fluids under pressure and which is highly reliable and precisely controllable.

It is a further object of my invention to provide a tool of the type described in the previous paragraph in which there is provided a novel and unique fluid regulating system operable by the user of the tool to accurately, precisely and deftly manipulate the gripping, cutting or perforating elements of the device.

It is still a further object of my invention to provide a tool of the type described in the preceding paragraph in which the regulating system comprises a valve seat through which fluid flows to operate the tool, a valve, an operator actuated mechanism for moving the valve relative to the valve seat, and an automatically acting assembly for moving the valve seat into engagement with the valve when predetermined levels of fluid pressure within the tool are reached.

More particularly, it is an object of my invention to provide a hand-held pneumatically-operated surgical tool for gripping, cutting or perforating bone, tissue or other structures of the human body in which variously configured object-engaging elements may be accurately and precisely manipulated by the user to perform various precise surgical operations.

It is a further object of my invention to provide a tool of the type described in the previous paragraph in which the object-engaging elements are carried by a pair of cooperating elongated blade-like members which are relatively movable in response to fluid flow into the tool in a manner so as to move the object-engaging elements into operable juxtaposition.

It is still a further object of my invention to provide a tool of the class described in which the object-engaging elements may conveniently be adjusted relative to the tool body for up, down or sidewise biting action.

It is another object of my invention to provide a tool of the class described in which variously configured object-engaging elements may be interchangeably used and in which the object-engaging elements may be easily disassembled for sterilization, sharpening or replacement.

It is still another object of my invention to provide a tool of the class described which may be quickly and easily coupled to either a remotely located source of pneumatic supply or to a portable supply which may be transported with the tool.

It is a further object of my invention to provide a tool of the type described in the preceding paragraphs which is safe to use and in which all fluids under pressure within the tool are automatically vented and the operating elements immediately separated when the operator control mechanism is released by the operator so as to return to its normal position.

According to the present invention, the foregoing and other objects are attained by providing a fluid operated assembly which, in response to fluid pressure, exerts forces on cooperating members to cause variously configured object-engaging elements to pressurally engage selected objects and materials, a valve seat through which fluid under pressure flows to act upon the fluid operated assembly, and a valve for regulating the flow of fluid through the valve seat. An operator actuated control is provided to move the valve relative to the valve seat to allow fluid to flow through the valve seat, and a novel and unique mechanism is provided for automatically moving the valve seat to reengage the valve when various predetermined levels of pressure are exerted upon the fluid operated assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the fluid operated tool of my invention partly in section to show internal construction.

FIG. 2 is a fragmentary view illustrating the fluid regulating valve means portion of the tool shown in FIG. 1, and enlarged to better illustrate the interrelationship of the component parts.

FIG. 3 is a fragmentary elevational view illustrating the position of the parts after the valving means has been opened, as a result of rearward pressure having been exerted on the trigger.

FIG. 4 is a fragmentary elevational view illustrating the position the parts will assume if no further pressure is exerted on the trigger.

FIG. 5 is a view taken along lines 5--5 of FIG. 1 illustrating the construction of the cooperating blade members.

FIG. 6 is a view taken along lines 6--6 of FIG. 1 illustrating the construction of the blade orientation ring assembly.

FIG. 7 is a side elevational view of another form of the object-engaging means of my invention which is used for perforating bone, tissue or other materials.

FIG. 8 is a side elevational view of still another form of the object-engaging means of my invention showing a double acting scissors type means for cutting or gripping bone tissue or other objects.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1 of the drawings, the preferred embodiment of my invention is shown to have a hand-held body or housing, generally designated by the numeral 10, having an upper barrel portion 12, a grip 14 and a trigger-like portion 16. Detachably secured to the forward end of barrel portion 12 is means, generally designated by the numeral 18, for gripping or cutting bone, tissue or other body structures. Means 18 is shown as comprising slidably engaged first and second elongate members or blades 20 and 22. Blades 20 and 22 are preferably constructed of a suitable hard and durable material capable of withstanding either chemical or elevated temperature surgical sterilization, and are provided with cooperating object-engaging means in the form of opposing jaws 24 and 26 which are adapted to be moved into and out of operative juxtaposition by relative sliding movement between members 20 and 22. Jaws 24 and 26 have beveled, sharp edges which define cup-shaped portions 28 and 30 respectively, which meet exactly when the jaws are approximated. As can more clearly be seen by referring to FIG. 5, blade member 22 is provided with a centrally located longitudinally extending grooved portion 32 adapted to slidably receive a longitudinally extending mating tongue portion 34 provided on member 20.

Referring to FIG. 1 and also to FIG. 6, it can be seen that blade member 22 at its rearward or right end, as viewed in FIG. 1, has a generally cylindrically-shaped section 36 having an axial opening or passageway 38 extending therethrough. Passageway 38 is constructed to closely receive the generally cylindrically-shaped rearward section 40 of member 20, and serves to hold members 20 and 22 in operable engagement with tongue 34 of member 20 in slidable engagement with grooved portion 32 of member 22. Rearwardly of opening 38, cylindrical section 36 is counter-bored to define an annular space 42 between blades 20 and 22, the purpose of which will presently be described. Cylindrical section 36 of blade 22 terminates in a radially extending flange 44 which protrudes into the forwardmost bore 46 of a plurality of generally cylindrically-shaped bores of differing diameter formed internally of barrel portion 12.

At the rearward extremity of bore 46 there is provided a circumferential groove which carries a split or snap ring 48. Ring 48 serves to longitudinally locate means for adjustably orienting gripping or cutting means 18 relative to body 10. This orienting or locating means is shown in the form of a locating ring 50 embodying in its forward face one or more detent mechanisms 52. A locking pin 54 is provided to position ring 50 circumferentially relative to housing 12.

The cylindrically-shaped section 40 of blade 20 extends through cylindrical section 36 of member 22, through locating ring 50, and into a chamber 55 formed within barrel 12, where it terminates in a radially extending flange 56. A biasing means for resisting forward movement of blade 20 relative to blade 22 is provided in the form of a compression spring 58 which surrounds cylindrical section 38. One end of spring 58 seats against flange 56 and the other end extends into annular space 42 where it seats against an internal shoulder of cylindrical section 36 of blade 22.

The forward portion of bore 46 is threaded internally to accommodate an externally threaded locking ring 60 which is provided with an axial bore 62 adapted to closely receive cylindrical section 36 of blade 22. The rearward face of locking ring 60 engages flange 44 of blade 22 so that when ring 60 is threadably secured to body 10, as shown in FIG. 1, the rearward face of flange 44 is held in contact with locating ring 50. The rearward face of flange 44 is provided with a plurality of depressions 64 which are adapted to receive balls 66 of spring loaded detent mechanisms 52.

As shown in FIG. 6, in the preferred embodiment of my invention, I provide four depressions in the rearward face of flange 44 spaced circumferentially at 90.degree. intervals so as to allow cutting or gripping means 18 to be positioned as may be required for upward, downward, right or left biting by jaws 24 and 26. Locking ring 60 is suitably knurled at its periphery to allow the surgeon to easily and quickly loosen the ring so as to allow rotation of the blade members relative to barrel portion 12. The spring-loaded detent mechanisms in cooperation with depressions 64 in flange 44 allow the surgeon by "feel" to accurately position the blades at 90.degree. intervals. When the blade members are located as desired, locking ring 60 may be conveniently tightened to lock the assemblage securely in place relative to body 10.

After surgery is completed, ring 60 may be easily loosened and separated from body 10, allowing blade members 20 and 22 to be withdrawn from barrel 12. The blade members may then be conveniently separated from each other for sterilization and sharpening if required.

Referring again to FIG. 1, grip 14 is provided with internal longitudinally extending gas inlet and exhaust chambers 70 and 72 respectively. A fitting 74 is provided at the inlet port of chamber 70 for quick coupling of the tool with a source of pneumatic supply such as compressed air, nitrogen or other gas. This supply (not shown) may be in the form of a remotely located gas supply bottle or compressor unit, or it may be in the form of a small pressurizable container which may be conveniently interconnected to, and transported with the surgical tool so as to make the tool fully portable and usable as an entirely self-contained unit.

At the outlet or upper end of chamber 70 is a passageway 76 which communicates with means, generally designated by the numeral 77, for regulating the flow of gases into a passageway 78 which in turn communicates with a means 80 which, in response to fluid pressure, functions to operate gripping or cutting means 18. Regulating means 77 forms an important part of my invention and will be discussed in detail in the paragraphs which follow.

Referring to FIGS. 1 and 3, blade operating means 80 which is operably controlled by regulating means 77 is shown housed within barrel portion 12 of body 10 and can be seen to comprise a pressure-responsive means shown in the form of piston assembly 82 mounted for reciprocal movement internally of barrel portion 12. Mounted within previously identified chamber 55 is a generally cylindrically-shaped cylinder member 86 having a head portion 90 and a skirt portion, the internal walls of which define piston chamber 92. Formed within barrel portion 12 rearwardly of, and immediately adjacent to, chamber 55 is a chamber 94 of slightly smaller diameter. Near the rearward-most portion of barrel 12, adjacent to and in communication with chamber 94, is a chamber 96 having a gas inlet passageway 98 which interconnects with previously identified passageway 78.

As can more clearly be seen by referring to FIGS. 3 and 4, pressure-responsive means, or piston assembly 82, comprises a first piston 100, having a stem 102, and a second piston 104 having a central bore 106 adapted to receive the rearward extremity of stem 102. An elastomeric O-ring 108 serves to sealably interconnect piston 104 and stem 102. Stem 102 is provided with a centrally located longitudinal bore or passageway 110 which communicates with an angularly extending passageway 112 in piston 100, which passageway communicates with the rearward face of piston 100. Piston 100 is provided with a central hub-like protuberance 114 on its forward face which is adapted to mate with axial passageway 116 in blade member 20 so as to hold the assemblages in axial alignment. Head portion 90 of cylinder member 86 is provided with an axially located opening 120 which is adapted to receive stem 102, thereby providing a path for the flow of gases between chambers 96 and 92 through passageways 110 and 112 of stem 102. Stem 102 is movable relative to head portion 90 as piston assembly 82 moves forwardly and rearwardly within barrel 12. An elastomeric O-ring 122 is located within opening 120 to provide a gas seal between stem 102 and head 90. Carried within grooves formed in the outer peripheries of pistons 100 and 104 are elastomeric O-rings 124 and 126 which similarly serve to form a gas-tight seal between the pistons and the inner walls of chambers 92 and 94 within which they reciprocate.

Although two pistons are provided in the preferred embodiment of my invention, it is to be understood that any number of pistons greater than one may be used. The novel cooperative coupling of two pistons, as I have illustrated, serves to increase the total effective piston area which may be exposed to gases while, at the same time, keeping the diameter of the pistons small. If the exertion of greater force upon cutting means 18 is desired for a given range of pnuematic pressures, additional pistons may be added in a manner similar to that illustrated. If lesser force is acceptable, only one piston may of course be used.

Referring now particularly to FIG. 3, when gases under pressure are controllably introduced into chamber 96 through passageways 78 and 98 by the operation of regulating means 77, the details of construction and operation of which will presently be described, pressure is exerted against piston 104, tending to urge it forwardly in chamber 94. As indicated by arrows 128, gases will also flow from chamber 96 through passageways 110 and 112 into an annular chamber 130 which is defined within chamber 92 by the rearward face of piston 100 and the forward surface of head 90. Gas pressure in chamber 130 will tend to urge piston 100 forwardly in chamber 92, and the forces thus generated coupled with the forces exerted by the gases in chambers 94 and 96 against piston 104 will combine to urge piston assembly 82 forwardly as a unit within barrel 12. To prevent pressure buildup in chamber 94 as piston 104 moves forwardly, I have provided an interconnecting passageway 134 through cylinder member 86 which passageway interconnects the portion of chamber 92 (FIG. 1) in advance of piston 100 and the portion of chamber 94 (FIG. 1) in advance of piston 104. As best seen in FIG. 3 the skirt portion of cylinder member 86 has a central section of reduced diameter and has a tapered slot-like opening formed at the lower portion of its forward extremity. Cylinder member 86 also has a tapered slot-like opening formed in the lower portion of its head section 90. When member 86 is in position within barrel 12, those tapered slots cooperate with the peripheral groove or channel formed between barrel 12 and the reduced diameter portion of cylinder member 86 to form passageway 134. Passageway 134 allows gases in chamber 94 to flow into chamber 92 and thence to atmosphere through an annular groove 135 formed in housing 10 which annular groove communicates with chamber 92 and with chamber 72 through exhaust passageways 135a and 135b respectively.

As the buildup of pressure against pistons 100 and 104 continues, piston assembly 82 will gradually and uniformly move forwardly against the urging of spring 58, causing blade 20 to correspondingly slowly and uniformly slide forwardly relative to blade 22. So long as gases under pressure continue to flow into chamber 96, the forward movement of blade member 20 will continue, causing jaws 24 and 26 to move toward mating approximation. When, however, as will be described in the paragraphs which follow, the flow of additional gases into chamber 96 ceases, the relative movement of the assemblages will cease and the system will achieve balanced equilibrium.

Referring now to FIG. 2, regulating means 77 which controls and regulates the flow of gases into chamber 96 can be seen to comprise a pressure-responsive means or piston 140 mounted for reciprocal movement within a generally cylindrically-shaped first chamber 142 formed within grip 14. Piston 140 has an axially extending skirt portion 144 and a head portion 146 which is provided with an elastomeric O-ring 148 adapted to form a seal between head 146 and the inner walls of chamber 142. Skirt portion 144 is mounted to slide axially into a second chamber 150, through an elastomeric O-ring carrying aperture 152 in the head portion of a generally cylindrically-shaped member 154 which is fixedly mounted intermediate of chambers 142 and 150. An axial passageway 156 through piston 140 serves to interconnect the portion 165 of chamber 142 which is in advance of, or to the left of piston 140 as viewed in FIG. 2, with chamber 150, and forms, at the rearward extremity of skirt portion 148, a valve seat 158.

Threadably carried within a chamber 160, which is located forwardly or to the left of chamber 142 as viewed in FIG. 2, is a valve bushing 162. At the rearward extremity of bushing 162 is a reduced diameter axially extending tubular portion 164 which engages the forward face of head 146 of piston 140 when the tool is at rest. Tubular portion 164 is provided with a plurality of slots or passageways in its side walls which communicate with chamber 165. Chamber 165, in turn, communicates with passageway 78 which interconnects with chamber 96 in barrel portion 12. A biasing means for urging piston 140 forwardly in chamber 142 is provided in the form of a compression spring 166 which is held captive within chamber 142 with one end engaging head 146 of piston 140.

Formed internally of valve bushing 162 is an axial passageway 168 and a communicating transversely extending passageway 170. Passageway 170 interconnects chamber 55 in barrel portion 12 with exhaust chamber 72 in grip 14 by means of passageways 135a and 135b, thereby serving as another exhause path by which gases may flow from chamber 55 to atmosphere. As will be discussed in greater detail in the section herein entitled "Operation" when the surgical tool is at rest, passageway 170 provides a vent path to atmosphere for the operating fluids under pressure which operate piston assembly 82. Passageway 168 serves as a guide for the telescopic movement of an elongated trigger extension rod 176 which protrudes rearwardly from a trigger member 177 which is mounted for reciprocal movement in chamber 178 located adjacent the forward face of grip 14. A set screw 180 connects rod 176 with trigger member 177, and a biasing means in the form of a compression spring 182 carried within a coaxial bore 184 within trigger member 177 urges against telescopic movement of trigger 177 into bore 178. Trigger extension rod 176 is of a length so as to extend into passageway 168 of bushing 162 to a point at which it partially, but not completely, closes passageway 170 when trigger member 177 is at rest in its forward-most position.

The numeral 184 identifies a valve which is mounted for axial movement within piston 140 and bushing 162, and serves to regulate the flow of gases through valve seat 158. One end of valve 184 is carried in a bore 186 in trigger extension rod 176 and the other end protrudes into chamber 150 terminating in a generally cylindrically-shaped head 188. An elastomeric O-ring 190 is carried within a peripheral groove in head 188, and is adapted to sealably engage seat 158 when the regulating means is in its normal position. A generally conical-shaped section 192 is provided intermediate of head 188 and the shank portion of valve 184 and serves to provide means for a fine adjustment of the flow of gases through seat 158 into passageway 156 as head 188 is moved away from seat 158.

As can best be seen in FIG. 2, trigger 177 and its cooperating trigger extension 176 provide means whereby valve 184 may be moved rearwardly relative to seat 158 so as to allow gases to flow into passageway 156. In a manner which will be described in the following section entitled "Operation," piston 140, being movable rearwardly in chamber 142 in response to pressure exerted on its forward face, provides means whereby seat 158 may be moved into reengagement with valve 184 when the pressure exerted thereon is sufficient to overcome the opposing forces of biasing means 166.

OPERATION

With the tool connected to a pneumatic supply by means of fitting 74 and with cutting or gripping means 18 properly oriented and secured to body 10 by means of ring 60, the device is ready for use by the surgeon. Upon pulling trigger member 177 inwardly, extension rod 176 moves rearwardly, sealing passageway 170 and causing valve stem 184 to move axially relative to bushing 162 and piston 140. As illustrated in FIG. 3, this rearward movement of valve 184 causes O-ring 190 to separate from seat 158, thereby allowing gases to flow, in the direction of arrows 194, into passageway 156 of piston 140. As indicated by arrows 196, gases will flow through passageway 156, pass through the openings in tubular portion 164 of bushing 162 into chamber 165, and thence into passageway 78 leading to chamber 96. From chamber 96 gases will impinge upon piston 104, as illustrated by arrows 198, and will also flow through passageways 110 and 112 into chamber 130, exerting pressure on the rearward face of piston 100. The forces thus exerted will cause piston assembly 82 to move forwardly against the urging of spring 58 from the position shown in FIG. 1 to the position shown in FIG. 3. This movement, of course, causes blade member 20 to be gradually moved slidably forward relative to blade member 22, bringing jaws 24 and 26 toward approximation. If trigger member 177 is held in the position illustrated in FIG. 3 and FIG. 4, i.e., is not pulled further rearwardly, the forces exerted by the gases against piston assembly 82 will equalize the opposing forces exerted by spring 58, and the various assemblages will remain in balanced equilibrium.

Turning to FIG. 4, it can be seen that as the gas pressure within the device equalizes and the forces tending to move the piston assembly forward balance the opposing forces generated by spring 58, forces will be exerted against the forward face of head 146 of piston 140 by the gases backing up within chamber 165. At the point where the force against piston 140 counterbalances the opposing force exerted by spring 166, piston 140 will separate from bushing 162, skirt portion 144 will move axially through aperture 152 in member 154, and seat 158 will again move into sealing engagement with O-ring 190 as shown in FIG. 4. Gases trapped within chamber 142 between piston 140 and member 154 are provided with a path to atmosphere in the form of passageway 193 formed internally of the body between grip 14 and barrel 12 (shown by dotted lines in FIGS. 3 and 4), leading to vent passageway 134 (FIG. 3) which in turn is in communication with atmosphere through passageways 135a and 135b and annular groove 135. Since, as previously pointed out, exhaust passageway 170 is blocked by member 176, and since gases can no longer flow through passageway 156 into chamber 96, the system will remain in equilibrium as illustrated in FIG. 4 until trigger member 177 is pulled further rearwardly by the surgeon. When trigger 177 is again moved rearwardly, valve stem 184 will be further moved axially rearwardly, causing O-ring 190 to again separate from seat 158. This will allow additional gas to flow through passageway 156 in piston 140, through passageway 78 into chamber 96, causing additional forces to be exerted against pistons 100 and 104 of a magnitude sufficient to further compress spring 58. This movement, of course, causes blade member 20 to move forwardly relative to blade member 22, further reducing the separation between jaws 24 and 26 and bringing them closer to mating juxtaposition. If rearward movement of trigger member 177 is again stopped, equalization will result and gases under pressure in chamber 165 will again cause piston 140 to move rearwardly into seating position with O-ring 190, once more stabilizing the system.

It is apparent that the novel and unique construction of the valve regulating means of my invention causes movement of the trigger member by the surgeon to be directly reflected into relative movement between blade members 20 and 22. This allows the surgeon to maintain precise controllability over relative movement between the blades. By gradually depressing the trigger member, jaws 24 and 26 can be deftly approximated so as to lightly engage the object to be gripped or cut. When the jaws of the blades are thusly positioned at the location chosen by the surgeon, a quick squeezing of trigger member 177 will result in an immediate surge of gas flow, causing a rapid increase in the pressure being exerted by jaw members 24 and 26, thereby causing the desired cutting or chipping action.

When trigger member 177 is released by the surgeon, spring 182 will urge it forwardly within chamber 176 until it reaches the position shown in FIG. 1. In this position it can be seen that exhaust passageway 170 is opened to atmosphere. As indicated in FIG. 2, gases exerting pressure on piston 140 will immediately flow through passageway 170 into exhaust chamber 72 to atmosphere, causing piston 140, due to the urging of spring 166, to again move into engagement with valve bushing 162. With trigger 177 in its forward position as illustrated in FIG. 1, O-ring 190 is in sealing engagement with seat 158, thereby precluding further flow of gas through the regulating means. Gases within chambers 94 and 96 will flow through passageways 98 and 78 into chamber 165, and thence through passageways 170 and 135b into exhaust chamber 72. Gases under pressure within chamber 92 tending to urge piston 100 forwardly against the urging of spring 58 will flow through openings in skirt portion 88 of cylinder 90 into exhaust passageway 170, thence into exhaust chamber 72. Compression spring 58 along with positive gas pressures formed in chambers 92 and 94 due to the opening of passageway 170 will urge blade member 20 and piston assembly 80 rearwardly within barrel portion 12 to the position illustrated in FIG. 1. In this position the tool is safely depressurized and in a static condition ready for the next manipulation by the surgeon.

In FIG. 7, I show another form of the object-engaging means of my invention. This form is adapted for use principally as a punch for perforating bone, tissue or other materials, and comprises telescopically-engaged first and second members 212 and 214. Member 212 which forms the punch body has a generally cylindrically-shaped elongated central body portion 216 terminating at its rearward or right end, as viewed in FIG. 7, in a generally cylindrically-shaped section 218 of increased diameter having a radially protruding flange 220. Member 212 terminates at its forward extremity in a head portion 222 which is generally U-shaped in cross section having spaced apart legs 224 and 226 which are interconnected by a cross member 228. Leg 226 is formed integrally with central body portion 216 and spaced apart leg or die member 124 is provided with a bore and counter-sink 230 which is concentric with body portion 216.

A longitudinal bore 224 which is coaxial with central body portion 216 extends through end section 218, central body portion 216 and leg 226. Bore 224 is adapted to slidably receive generally cylindrically-shaped member 214 which forms the punch element. A counterbore 230 in end section 218 is arranged to receive the rearward end section of punch element 214 which is of enlarged diameter, has a counterbore 232, and a radially extending flange 234. Punch element 214 has near its forward extremity reduced diameter sections 236 and 238, the forwardmost of which is receivable in bore 230 in leg or die member 224, and the second of which is closely receivable in a central bore provided in a stop screw 240. Stop screw 240 has a threaded shank portion which is threadably received in bore 224 through leg 226, and an enlarged diameter head 241 disposed between legs 224 and 226. By threading the stop screw in and out of bore 224, the spacing between its forward face and the rear face of leg or die member 124 may be adjusted so that the material to be perforated may be gripped firmly therebetween. To assist in gripping and supporting the material, the rearward face of die member 124 is provided with transverse tooth-like striations.

This form of object-engaging means is adapted to be removably secured to body 10 in the same manner as the object-engaging means 18 of the preferred embodiment of my invention, as previously described. A locating ring 236 which may be threadably secured to body 10 serves to position the rear face of flange 220 of member 212 in contact with locating ring 50 and flange 234 of member 214 in engagement with piston assembly 82. The rear face of flange 220 is provided with a plurality of depressions adapted to receive balls 66 of detent mechanism 52 so that the orientation of the assemblage relative to the body may be easily adjusted in the manner previously described. A biasing means for urging relative separation between members 212 and 214 is provided in the form of a spring 238 positioned around member 214 and in engagement with an internal shoulder 240 near the rear of member 212 and flange 234 of member 214.

In FIG. 8, I show still another form of the object engaging means of my invention.

This form, which is a double acting type of mechanism, is adapted for use in gripping, cutting or chipping bone or other structures in situations where a scissors-type of action is desirable. As is the case in the previously described embodiment, this form of object-engaging means can be quickly and easily removably secured to body 10 in the same manner as the object-engaging means of the preferred embodiment of my invention.

As shown in FIG. 8, a main body member, designated by the numeral 250, is provided with a stationary jaw 252 at its forward or left extremity as viewed in FIG. 8, and has a generally cylindrically-shaped section 254 at its other extremity. A flange 256 protrudes radially from section 254 and, as in the previously described forms, is provided with a plurality of orientation depressions 257 on its rearward face which are adapted to receive balls 66 of detent mechanism 52 when member 250 is secured to body 10 by locating ring 60 (not shown). A longitudinal bore 258 extends through section 254 and slidably receives a generally cylindrically-shaped section 260 formed at the rearward extremity of a movable jaw assembly 262. When this form of object-engaging means is secured to the hand-held body of the tool in the manner previously described, section 260 protrudes into body 10 and is held in engagemnt with piston assembly 82 by a biasing means (not shown) which resists its forward movement as the piston assembly moves forwardly within barrel portion 12.

As indicated by the phantom lines in FIG. 8, when section 260 is in its normal position with piston assembly 82 at rest, jaw portion 264 of jaw member 262 is separated from stationary jaw 252. Jaw portion 264 is pivotally connected near its mid-point to main body member 250 by a pivot pin 266 and is pivotally connected at its rearward extremity to linkage member 268 by pivot pin 270. Linkage member 268 iS, in turn, pivotally connected at 272 to the forward extremity of cylindrical section 260.

When piston assembly 82 moves forwardly during the operation of the tool by the surgeon, section 260 moves telescopically within bore 258, causing pivot point 272 to move forwardly to the position shown in the solid lines in FIG. 8. This forward movement causes movable jaw 264 to pivot about pivot pin 266 and to move gradually and controllably into juxtaposition with stationary jaw 252. In this way, objects may be lightly gripped by the surgeon for manipulation or inspection. Further rearward movement of the trigger assembly of the tool will, of course, result in the generation of significant pressures between the jaws for cutting or chipping by opposing cutting edges 274 formed in the jaws for such purpose.

It is to be understood that numerous types of object-engaging means, in addition to those illustrated herein, can be used with the hand-held body portion of my invention and that the scope of my invention is not intended to be limited to the embodiments shown.

Claims

I claim:

1. A fluid operated tool comprising:

a. means responsive to fluid pressure for generating mechanical forces;

b. a valve seat through which fluid under pressure flows to said pressure-responsive means;

c. a valve for regulating the flow of fluid through said valve seat;

d. means for disengaging said valve from said valve seat; and

e. means for moving said valve seat into reengagement with said valve when pressures exerted against said pressure-responsive means reach predetermined levels.

2. The tool as defined in claim 1 including means for pressurally engaging objects and materials, said means being operable by mechanical forces generated by said pressure-responsive means.

3. The tool as defined in claim 2 in which the means for pressurally engaging objects and materials comprises first and second cooperatively interconnected members adapted to be relatively movable by the mechanical forces generated by said pressure-responsive means.

4. The tool as defined in claim 3 in which said first and second cooperatively interconnected members are provided with cutting means operable by relative movement between said first and second members for cutting objects and materials.

5. The tool as defined in claim 3 in which said first and second cooperatively interconnected members are provided with gripping means operable by relative movement between said first and second members for gripping objects and materials.

6. The tool as defined in claim 3 in which said first and second cooperatively interconnected members are provided with perforating means operable by relative movement between said first and second members for perforating objects and materials.

7. The tool as defined in claim 1 including means for venting to atmosphere fluids under pressure within the tool, said means being operable by said means for disengaging said valve from said valve seat.

8. A fluid operated tool comprising:

a. a body;

b. first and second cooperating members carried by said body, said members having means operable by relative movement between said members for pressurally engaging various structures;

c. means responsive to fluid pressure for urging relative movement between said first and second members; and

d. means for regulating the flow of fluid to said pressure-responsive means comprising:

1. a valve seat through which fluid under pressure flows to said pressure-responsive means;

2. a valve for regulating the flow of fluid through said valve seat;

3. means for moving said valve relative to said valve seat; and

4. means for automatically moving said valve seat into engagement with said valve to stop fluid flow to said pressure-responsive means when various predetermined levels of pressure are exerted on said pressure-responsive means.

9. The fluid operated tool as defined in claim 8 including means for urging against movement of said valve seat into engagement with said valve.

10. The fluid operated tool as defined in claim 8 in which the means for automatically moving said valve seat into engagement with said valve is movable in response to fluid pressure.

11. The fluid operated tool as defined in claim 10 in which said means for automatically moving said valve seat into engagement with said valve comprises a piston carrying said valve seat.

12. The fluid operated tool as defined in claim 8 in which said means for moving said valve relative to said valve seat comprises a trigger carried by said body adapted to cooperatively engage said valve.

13. The fluid operated tool as defined in claim 8 in which said means for urging relative movement between said first and second members comprises at least one piston movable within said body in response to fluid pressure.

14. The fluid operated tool as defined in claim 8 including biasing means urging against relative movement between said first and second members.

15. The fluid operated tool as defined in claim 8 in which said means for pressurally engaging various structures comprises opposing jaws movable into operative juxtaposition by relative movement between said first and second members.

16. The tool as defined in claim 15 including means for adjustably positioning said first and second members relative to said body portion so as to position said jaws in various angular orientations relative to said body.

17. The tool as defined in claim 15 in which said means for pressurally engaging various structures is adapted to cut various materials.

18. The tool as defined in claim 8 including means for venting to atmosphere fluids under pressure within the tool, said means being operable by said means for moving said valve relative to said valve seat.

19. A fluid operated surgical tool comprising:

a. a hand-held body;

b. first and second slidably interconnected members carried by said body, said members having opposing jaws adapted to be moved into pressural engagement with an object by relative movement between said first and second members;

c. pressure-responsive means for urging relative movement between said first and second members, said pressure-responsive means comprising at least one piston mounted for reciprocal movement within said body;

d. means for supplying fluids under pressure to said pressure-responsive means; and

e. means for regulating the flow of fluids to said pressure-responsive means of said regulating means comprising:

1. a valve means operably associated with said fluid supply means for controlling the flow of fluids to said pressure-responsive means;

2. means operable by the user of the tool for opening said valve means to permit various rates of flow of fluids to said pressure-responsive means;

3. means for automatically closing said valve means so as to stop the flow of fluids to said pressure-responsive means when fluid pressures acting on said pressure-responsive means reach various levels; and

4. means for automatically venting to atmosphere fluids acting upon said pressure-responsive means when said means operable by the user of the tool for opening said valve means is not in operation.

20. The surgical tool as defined in claim 19 in which said pressure-responsive means for urging relative movement between said first and second members comprises two operatively associated pistons mounted for reciprocal movement within said body.

21. The surgical tool as defined in claim 19 including means for urging against relative movement between said first and second members tending to move said opposing jaws into pressural engagement with an object.

22. The surgical tool as defined in claim 19 in which said means for automatically closing said valve means comprises a piston movable in response to fluid pressure to close said valve means.

23. The surgical tool as defined in claim 20 in which said piston has a valve seat adapted to cooperate with said means operable by the user of the tool for opening said valve means for controlling the flow of fluids to said pressure-responsive means.

24. A fluid operated surgical tool as defined in claim 19 in which said first and second slidably interconnected members have pivotally interconnected jaws, said jaws being movable into operable juxtaposition by relative movement between said first and second members due to the urging of said pressure-responsive means.