Surgical instrument

• US 5,620,459 A
• Filed: 04/25/1995
• Issued: 04/15/1997
• Est. Priority Date: 04/15/1992
• Status: Expired due to Fees

• Current Assignee: Microsurge, Inc. (Imagyn Medical Technologies, Inc.)
• Original Assignee: Microsurge, Inc. (Imagyn Medical Technologies, Inc.)
• Inventors: Lichtman, Philip R.
• Primary Examiner(s): Buiz, Michael Powell
• Assistant Examiner(s): LEWIS, WILLIAM W
• Application Number:
  US08/428,275
• Time in Patent Office: 721 Days
• Field of Search: 606/51, 606/52, 606/174, 606/205-211, 128/750-755, 604/22
• US Class Current: 606/205
• CPC Class Codes: A61B 17/29 Forceps for use in minimally invasive surgery
• CPC Class Codes: A61B 17/2909 Handles
• CPC Class Codes: A61B 17/30 Surgical pincettes without pivotal connectionsfor holding suture needles or materials A61B17/0483; wound clamps A61B17/08 ; hand-held gripping tools without pivotal connections in general B25B9/02
• CPC Class Codes: A61B 17/320016 Endoscopic cutting instruments, e.g. arthroscopes, resectoscopes A61B10/0233, A61B17/29, A61B17/3207 take precedence
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 18/1442 Probes having pivoting end effectors, e.g. forceps
• CPC Class Codes: A61B 18/1445 at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod
• CPC Class Codes: A61B 2017/2825 Inserts of different material in jaws
• CPC Class Codes: A61B 2017/2923 Toothed members, e.g. rack and pinion
• CPC Class Codes: A61B 2017/2937 with flexible part
• CPC Class Codes: A61B 2017/2943 Toothed members, e.g. rack and pinion
• CPC Class Codes: A61B 2017/2946 Locking means
• CPC Class Codes: A61B 2017/3445 used as instrument channel for multiple instruments catheters A61B2017/22072
• CPC Class Codes: A61B 2090/0813 Accessories designed for easy sterilising, i.e. re-usable
• CPC Class Codes: A61B 2217/005 with suction drainage system

Abstract

A surgical instrument is provided of the type having first and second telescoping shafts, a jaw assembly comprising two jaws carried by the front end of the first shaft, and a novel handle mechanism, and connecting member for connecting the rear ends of the two shafts to the novel handle mechanism, so that manipulation of the handle mechanism by the surgeon will cause relative reciprocal axial motion of the two shafts, thereby resulting in opening and closing of the jaws. In a preferred embodiment, the novel handle mechanism comprises a first fixed handle member, a second movable handle member, gear member connecting the two handle members so that when the handles are moved relative to one another in a first direction, the jaws will be squeezed into clamping relation with tissue by the collet-like action of the second shaft moving in a first direction relative to the second shaft, and spring member for urging the second shaft to move in a direction to open the jaws. The instrument may include a device for conducting electrosurgery, releasable locking member for locking the two handle members so that the jaws are releasably locked in gripping engagement with tissue, a reversing gear for reversing the effect of movement of the two handle members on the two jaws so as to accommodate jaw mechanisms of different designs, and/or device for conducting cleaning of the instrument or irrigation of the surgical site.

Claims

1. A surgical instrument comprising:

a handle housing with a first handle member affixed thereto, and at least first and second concentrically arranged shafts extending longitudinally away from said housing, said first and second shafts each having proximal and distal ends with said proximal ends extending into said handle housing, said second shaft being affixed to said housing at its proximal end so as to be immobile with respect to said housing, and said first shaft surrounding said second shaft and being arranged to translate longitudinally with respect to said second shaft;

a jaw unit carried by said distal end of said second shaft, said jaw unit comprising at least two jaws, a rear section, and intermediate leaf spring elements connecting each of said jaws to said rear section, said leaf spring elements biasing said jaws so that when said leaf spring elements are unrestrained, said jaws are deployed in angular spaced relation with one another;

said first shaft having a length such that when said first shaft is caused to translate towards the distal end of said second shaft, the distal end of said first shaft will slide over said jaw unit and mechanically cause said jaws to close towards one another;

translation means for causing said first shaft to translate longitudinally relative to said second shaft, said translation means comprising a second handle member mounted for pivotal movement relative to said first handle member, gear rack means on said proximal end of said first shaft, and gear means coupled to said second handle member and engaged with said gear rack means for causing reciprocal movement of said first shaft relative to said second shaft, whereby to cause said first shaft to move into and out of jaw closing relation with said jaws; and

cooperating pawl and teeth means located within said housing for preventing movement of said first shaft relative to said second shaft in a first direction while permitting relative movement in a second opposite direction.

2. A surgical instrument according to claim 1 further including spring means within said housing for biasing said first shaft against movement in a direction to effect closing of said jaws.

3. A surgical instrument according to claim 1 wherein said teeth and pawl means comprises a plurality of aligned teeth carried by said first shaft, and a pawl engageable with said teeth, said pawl being fixed to said housing and being disposed so that it permits movement of said first shaft in said first direction but not in said second opposite direction.

4. A surgical instrument according to claim 3 further including a sleeve attached to said proximal end of said first shaft, said aligned teeth being carried by said sleeve.

37. A surgical instrument according to claim 3 wherein said pawl is a resilient spring member anchored at one end to said housing.

5. A surgical instrument comprising:

a housing provided with an internal bore, and at least first and second concentrically arranged shafts coupled to and extending longitudinally away from said housing, said second shaft having proximal and distal ends and being affixed to said housing at its proximal end so as to be immobile with respect to said housing, and said first shaft surrounding said second shaft and being arranged to move longitudinally with respect to said second shaft;

a jaw piece affixed to said distal end of said second shaft, said jaw piece being an integral structure comprising at least two jaws which are biased and normally deployed away from one another, a rear section, and intermediate leaf spring elements connecting each of said jaws to said rear section;

translation means for causing said first shaft to translate longitudinally relative to said second shaft, whereby when said first shaft is caused to translate towards the distal end of said second shaft, said first shaft will slide over said leaf spring elements and coact therewith to cause said jaws to close towards one another; and

unidirectional locking means for preventing relative telescoping movement of said first and second shafts in a first direction while permitting relative telescoping movement in a second opposite direction;

wherein said second shaft is hollow, and

further wherein the jaw piece has a hole extending through it and communicating at one end with the interior of said second shaft and at its other end to the space between said jaws,

thereby permitting an ancillary device to be extended through said second shaft to the region of said jaws.

6. An instrument according to claim 5 wherein the proximal end of said second shaft terminates at a rear end of said housing, thereby adapting said instrument for introduction of the ancillary device.

7. A surgical instrument comprising:

a housing provided with an internal bore, and at least first and second concentrically arranged shafts coupled to and extending longitudinally away from said housing, said second shaft having proximal and distal ends and being affixed to said housing at its proximal end so as to be immobile with respect to said housing, and said first shaft surrounding said second shaft and being arranged to move longitudinally with respect to said second shaft;

a jaw piece affixed to said distal end of said second shaft, said jaw piece being an integral structure comprising at least two jaws which are biased and normally deployed away from one another, a rear section, and intermediate leaf spring elements connecting each of said jaws to said rear section;

translation means for causing said first shaft to translate Iongitudinally relative to said second shaft, whereby when said first shaft is caused to translate towards the distal end of said second shaft, said first shaft will slide over said leaf spring elements and coact therewith to cause said jaws to close towards one another; and

unidirectional locking means for preventing relative telescoping movement of said first and second shafts in a first direction while permitting relative telescoping movement in a second opposite direction;

wherein said translation means comprises a stationary handle member and a movable handle member pivotally secured to said stationary handle member, and means on said movable handle member for engaging means affixed to said second shaft for translating said second shaft relative to said first shaft in response to relative movement of said handle members.

8. A surgical instrument for grasping objects at a remote location comprising:

a handle mechanism comprising a housing, a first handle member formed integral with said housing, a second handle member, and means pivotally connecting said first and second handle members so that said second handle member can pivot relative to said first handle member;

first and second concentrically arranged shafts having proximal and distal ends, with said proximal ends extending into said housing, said first shaft being fixed relative to said housing and said first handle member and said second shaft being movable axially relative to said first shaft;

translating means coupling the proximal end of said second shaft to said second handle member so that said second shaft will move axially relative to said first shaft as said second handle member is pivoted relative to said first handle member, said translating means comprising first gear means on said second shaft and second gear means affixed to said second handle member, said second gear means being mechanically coupled to said first gear means so as to cause said second shaft to move axially relative to said first shaft in accordance with pivotal movement of said second handle member;

a unitary jaw piece affixed to said first shaft at its distal end, said jaw piece having at least two jaws which normally are deployed away from one another in an open position, whereby when said second shaft is caused to translate towards the distal end of said first shaft, said second shaft will overlap said jaw piece and cause said jaws to close towards one another; and

biasing means within said housing for urging said second shaft to translate toward the proximal end of said first shaft.

9. An instrument according to claim 8 wherein said first gear means is a gear rack and said second gear means is a curved gear segment.

10. An instrument according to claim 9 further including releasable locking means for preventing movement of said second shaft relative to said first shaft in one axial direction while permitting movement in a second opposite direction.

36. An instrument according to claim 10 further including manually operable means carried by said housing for selectively disabling said locking means, whereby to permit bidirectional relative movement of said second shaft.

39. A surgical instrument according to claim 36 wherein said manually operable means is movably mounted to said handle housing and is movable between a first position in which said pawl and teeth are engaged with one another and a second position in which it prevents engagement of said pawl and teeth.

11. A surgical instrument comprising:

a hollow outer shaft having a longitudinal axis, a first proximal end, and a first distal end;

an inner shaft coaxially disposed in said outer shaft, said inner shaft having a second proximal end and a second distal end;

means for surgical interaction with animal tissue attached to the distal end of said inner shaft, said surgical interaction means comprising first and second tissue interacting members movable relative to one another between a first open position and a second closed position by axially directed changes in the relative positions of said first and said second distal ends of said shafts; and

a handle mechanism coupled to said outer and inner shafts for effecting relative axial movement of said shafts and thereby changing the relative positions of said first and said second distal ends lengthwise of said longitudinal axis;

said handle mechanism comprising a housing that surrounds the proximal ends of said shafts, means securing one of said shafts to said housing so as to prevent movement thereof relative to said housing, a first handle member affixed to said housing, driver-responsive means attached to the other of said shafts, a second handle member, pivot means connecting said second handle member to said first handle member, said second handle member being movable on its pivot relative to said first handle member between first and second operating positions, driver means carried by said second handle member engageable with said driver-responsive means for effecting axial movement of said other shaft relative to said one shaft in response to movement of said second handle member from one to the other of said first and second operating positions; and

unidirectional locking means for locking said shafts against relative axial movement in one predetermined direction, said unidirectional locking means being disposed within said housing and comprising a plurality of teeth connected to and movable with said other shaft, and a pawl in the form of a resilient spring member engageable with said teeth, said teeth and pawl being arranged so as to permit axial movement of said other shaft in a first axial direction while preventing axial movement of said other shaft in a second opposite axial direction.

12. An instrument according to claim 11 wherein said panel is anchored to said housing.

13. An instrument according to claim 11 further including manually operable means for selectively moving said pawl out of engagement with said teeth, whereby to allow bidirectional movement of said second handle member relative to said first handle member.

14. An instrument according to claim 13 wherein said manually operable means comprises a cam for camming said pawl out of engagement with said teeth, and lever means connected to said cam but projecting outside of said handle mechanism for rotating said cam, and further including means for releasably holding said lever means against movement.

15. An instrument according to claim 11 wherein said driver-responsive means comprises an axially-extending gear rack on said other shaft, and said driver means comprises gear teeth carried by said second handle member and a reversing gear coupling said gear teeth to said gear rack.

16. An instrument according to claim 11 wherein said outer shaft is fixed to said first handle member and said inner shaft is movable axially relative to said first handle member.

17. An instrument according to claim 11 wherein said inner shaft is fixed to said first handle member and said outer shaft is movable axially relative to said first handle member.

18. An instrument according to claim 11 wherein at least one space exists between said outer and inner shafts, and further including means for introducing fluid to or removing fluid from said at least one space.

19. An instrument according to claim 18 further characterized by at least one radially-extending opening in said outer shaft, and a collar assembly surrounding said outer shaft, said collar having a chamber that communicates with said at least one radially-extending opening and a port that permits fluid to be introduced to or removed from said chamber.

20. An instrument according to claim 19 wherein said collar is provided with a fitting that is coupled to said port and is adapted to be connected to an auxiliary device.

38. an instrument according to claim 11 wherein said driver-responsive means comprises a gear rack on said other shaft, said gear rack extending longitudinally of said other shaft, and said driver means comprises a curved gear segment on said second handle member, said curved gear segment being engaged with said rack.

40. A surgical instrument according to claim 13 wherein said manually operable means comprises an elongate member mounted to said housing, said elongate member being rotatable on its longitudinal axis relative to said housing, said elongate member having a cam portion within said handle housing adapted to cause said pawl to move into and out of engagement with said teeth as said elongate member is rotated on its longitudinal axis between first and second positions, and lever means attached to said elongate member outside of said handle housing for selectively rotating said elongate member from one to the other of its said first and second positions.

41. A surgical instrument according to claim 11 wherein said teeth are arranged in a line and are shaped so that when they are engaged by said pawl, said pawl will prevent relative axial movement of said shafts in a first direction but will allow relative axial movement of said shafts in a second opposite direction.

42. A surgical instrument according to claim 41 further including spring means urging said shafts to undergo relative movement in said second direction.

21. A surgical instrument comprising:

a handle housing with a first handle member affixed thereto, and at least first and second concentrically arranged shafts extending longitudinally away from said housing, said second shaft having proximal and distal ends and being affixed to said housing at its proximal end so as to be immobile with respect to said housing, and said first shaft surrounding said second shaft and being arranged to translate longitudinally with respect to said second shaft;

a jaw unit carried by said distal end of said second shaft, said jaw unit comprising at least two jaws, a rear section, and intermediate leaf spring elements connecting each of said jaws to said rear section, said leaf spring elements biasing said jaws so that when said leaf spring elements are unrestrained, said jaws are deployed in angular spaced relation with one another;

said first shaft having a length such that when said first shaft is caused to translate towards the distal end of said second shaft, the distal end of said first shaft will slide over said jaw unit and mechanically cause said jaws to close towards one another;

translation means for causing said first shaft to translate longitudinally relative to said second shaft, said translation means comprising a second handle member mounted for pivotal movement relative to said first handle member, gear rack means carried by said first shaft, and gear means coupled to said second handle member and engaged with said gear rack means for causing reciprocal movement of said first shaft relative to said second shaft, whereby to cause said first shaft to move into and out of jaw closing relation with said jaws;

first and second cooperating means for preventing movement of said first shaft relative to said second shaft in a first direction while permitting relative movement in a second opposite direction, said first cooperating means comprising a plurality of aligned teeth carried by said first shaft, and said second cooperating means comprising a pawl engageable with said teeth, said pawl being disposed so that it permits movement of said first shaft in said first direction but not in said second opposite direction; and

means for camming said pawl out of engagement with said teeth, whereby to permit said first shaft to be moved in said second opposite direction relative to said second shaft.

22. A surgical instrument comprising:

a handle housing with a first handle member affixed thereto, and at least first and second concentrically arranged shafts extending longitudinally away from said housing, said second shaft having proximal and distal ends and being affixed to said housing at its proximal end so as to be immobile with respect to said housing, and said first shaft surrounding said second shaft and being arranged to translate longitudinally with respect to said second shaft;

a jaw unit carried by said distal end of said second shaft, said jaw unit comprising at least two jaws, a rear section, and intermediate leaf spring elements connecting each of said jaws to said rear section, said leaf spring elements biasing said jaws so that when said leaf spring elements are unrestrained, said jaws are deployed in angular spaced relation with one another;

said first shaft having a length such that when said first shaft is caused to translate towards the distal end of said second shaft, the distal end of said first shaft will slide over said jaw unit and mechanically cause said jaws to close towards one another;

spring means for biasing said first shaft against movement in a direction to effect closing of said jaws;

translation means for causing said first shaft to translate longitudinally relative to said second shaft, said translation means comprising a second handle member mounted for pivotal movement relative to said first handle member, gear rack means carried by said first shaft, and gear means coupled to said second handle member and engaged with said gear rack means for causing reciprocal movement of said first shaft relative to said second shaft, whereby to cause said first shaft to move into and out of jaw closing relation with said jaws; and

first and second cooperating means for preventing movement of said first shaft relative to said second shaft in a first direction while permitting relative movement in a second opposite direction, said first cooperating means comprising a sleeve attached to said proximal end of said first shaft, said sleeve having a plurality of aligned teeth, and said second cooperating means comprising a pawl engageable with said teeth, said pawl being disposed so that it permits movement of said first shaft in said first direction but not in said second opposite direction.

23. A surgical instrument comprising:

a housing provided with an internal bore, and at least first and second concentrically arranged shafts coupled to and extending longitudinally away from said housing, said second shaft being hollow and having proximal and distal ends and being affixed to said housing at its proximal end so as to be immobile with respect to said housing, and said first shaft surrounding said second shaft and being arranged to move longitudinally with respect to said second shaft;

a jaw piece affixed to said distal end of said second shaft, said jaw piece being an integral structure comprising at least two jaws which are biased and normally deployed away from one another, a rear section, and intermediate leaf spring elements connecting each of said jaws to said rear section, said rear section of said jaw piece having a hole extending through it with one end of said hole communicating with the interior of said second shaft and the other end of said hole communicating with the space between said jaws, thereby permitting an ancillary device to be extended through said second shaft to the region of said jaws;

translation means for causing said first shaft to translate longitudinally relative to said second shaft, whereby when said first shaft is caused to translate towards the distal end of said second shaft, said first shaft will slide over said leaf spring elements and coact therewith to cause said jaws to close towards one another; and

unidirectional locking means for preventing longitudinal translating movement of said first shaft relative to said second shaft in a first direction while permitting longitudinal translating movement of said first shaft in a second opposite direction.

24. An instrument according to claim 23 wherein the proximal end of said second shaft terminates at a rear end of said housing, thereby adapting said instrument for introduction of an ancillary device.

25. An instrument according to claim 23 wherein said translation means comprises a stationary handle member affixed to said housing and a movable handle member pivotally secured to said stationary handle member, and means on said movable handle member for engaging means affixed to said first shaft for causing longitudinal translating of said first shaft relative to said second shaft in response to pivotal movement of said movable handle member relative to said first handle member.

26. An instrument according to claim 23 further including an electrically insulating sheath affixed to the distal end of said first shaft.

27. An instrument according to claim 23 wherein said locking means comprises first and second cooperating members located within said housing, with one of said cooperating members being attached to said first shaft and the other of said cooperating members being attached to said housing.

28. A surgical instrument comprising:

a hollow outer shaft having a longitudinal axis, a first proximal end, and a first distal end;

an inner shaft coaxially disposed in said outer shaft, said inner shaft having a longitudinal axis, a second proximal end and a second distal end, said shafts being capable of relative reciprocal axial movement;

means for surgical interaction with animal tissue attached to the forward end of one of said shafts, said surgical interaction means comprising first and second tissue interacting members movable relative to one another between a first open position and a second closed position by axially directed changes in the relative positions of said first and said second distal ends; and

a handle mechanism coupled to said outer and inner shafts for effecting relative axial movement of said shafts and thereby changing the relative positions of said first and said second distal ends lengthwise of said longitudinal axis;

said handle mechanism comprising a first handle member affixed to the proximal end of one of said shafts, driver-responsive means attached to the other of said shafts, a second handle member, means mounting said second handle member so that it is movable relative to said first handle member between first and second operating positions, driver means carried by said second handle member engageable with said driver-responsive means for effecting reciprocal axial movement of said other shaft relative to said one shaft in response to movement of said second handle member between said first and second operating positions; and

unidirectional locking means for locking said shafts against relative axial movement in one predetermined direction, said unidirectional locking means comprising a plurality of teeth connected to and movable with said other shaft, and a pawl in the form of a resilient spring member engageable with said teeth, said teeth and pawl being arranged so as to permit axial movement of said other shaft in a first axial direction while preventing axial movement of said other shaft in a second opposite axial direction.

29. An instrument according to claim 28 wherein said teeth are formed on a sleeve that is affixed to said other shaft.

30. An instrument according to claim 28 further including manually operable cam means for selectively moving said pawl out of engagement with said teeth, whereby to allow bidirectional relative axial movement of said shafts.

31. An instrument according to claim 30 wherein said manually operable cam means comprises a cam for camming said pawl out of engagement with said teeth, and lever means connected to said cam but projecting outside of said handle mechanism for rotating said cam, and further including means for releasably holding said lever means against movement.

32. A surgical instrument comprising:

a hollow outer shaft having a longitudinal axis, a first proximal end and a first distal end;

an inner shaft coaxially disposed in said outer shaft with a space existing between said shafts, said inner shaft having a longitudinal axis, a second proximal end, and a second distal end, said shafts being disposed for relative axial movement;

means for surgical interaction with animal tissue attached to the distal end of said inner shaft, said surgical interaction means comprising first and second tissue interacting members movable relative to one another between a first open position and a second closed position by axially directed changes in the relative positions of said first and said second distal ends;

a handle mechanism coupled to said outer and inner shafts for effecting relative axial movement of said shafts and thereby changing the relative positions of said first and said second distal ends lengthwise of said longitudinal axis;

said handle mechanism comprising a first handle member affixed to the proximal end of said inner shaft, driver-responsive means attached to said outer shaft, a second handle member pivotally connected to said first handle member and movable relative to said first handle member between first and second operating positions, driver means carried by said second handle member engageable with said driver-responsive means for effecting reciprocal axial movement of said outer shaft relative to said inner shaft in response to movement of said first handle member between said first and second operating positions; and

unidirectional locking means for locking said first and second handle members against relative movement in one predetermined direction; and

means for introducing fluid to or removing fluid from said space.

33. An instrument according to claim 32 further characterized by at least one radially-extending opening in said outer shaft, and a collar assembly surrounding said outer shaft, said collar assembly having a chamber that communicates with said at least one radially-extending opening and a port that permits fluid to be introduced to or removed from said chamber.

34. An instrument according to claim 33 wherein said collar assembly is provided with a fitting that is coupled to said port and is adapted to be connected to an auxiliary device.

35. An instrument according to claim 34 wherein said auxiliary device is a syringe.

43. A surgical instrument comprising:

a handle assembly;

an elongate dual shaft assembly having a proximal end retained within said handle assembly and a distal end to which is mounted a jaw assembly having at least two jaws that are movable relative to one another between open and closed positions, said shaft assembly comprising inner and outer shafts with one shaft movable axially relative to other and said jaw assembly being arranged so that said jaws are urged to a closed position when said shafts undergo relative axial movement in a first direction, said handle assembly being operable to provide relative axial motion between said inner and outer shafts;

a ratchet device coupled between said dual shaft assembly and said handle assembly at the proximal end of said shaft assembly within said handle assembly, said ratchet device comprising a first member comprising a plurality of teeth, and a second member engageable with the teeth on said first member, said first and second members being movable relative to one another as the shafts undergo relative axial movement in response to operation of said handle assembly, the relative motion between said first and second members causing locking engagement and disengagement of second member and said teeth, and said teeth and said second member being arranged so that when they are engaged the ratchet device will allow the shafts to undergo relative axial movement in said first direction but prevent the shafts from undergoing relative axial movement in a second opposite direction.

44. A surgical instrument according to claim 43 further including selectively operable means for preventing engagement of said teeth and said second member, whereby said shafts are free to be moved axially relative to one another in said first or second directions by operation of said handle assembly.

45. A surgical instrument comprising:

a hollow outer shaft having a longitudinal axis, a first proximal end, and a first distal end;

an inner shaft coaxially disposed in said outer shaft, said inner shaft having a longitudinal axis, a second proximal end and a second distal end, said shafts being capable of relative reciprocal axial movement;

means for surgical interaction with animal tissue attached to the distal end of one of said shafts, said surgical interaction means comprising first and second tissue interacting members movable relative to one another between a first open position and a second closed position by axially directed changes in the relative positions of said first and said second distal ends; and

a handle mechanism coupled to said outer and inner shafts for effecting relative axial movement of said shafts and thereby changing the relative positions of said first and said second distal ends lengthwise of said longitudinal axis;

said handle mechanism comprising a first handle member affixed to the proximal end of one of said shafts, driver-responsive means attached to the other of said shafts, a second handle member, means mounting said second handle member so that it is movable relative to said first handle member between first and second operating positions, driver means carried by said second handle member engageable with said driver-responsive means for effecting reciprocal axial movement of said other shaft relative to said one shaft in response to movement of said second handle member between said first and second operating positions; and

ratchet means located within said housing for preventing axial movement of said other shaft relative to said one shaft in one predetermined axial direction while permitting axial movement of said other shaft in a second opposite axial direction.

46. An instrument according to claim 45 further including selectively operable means for disabling said ratchet means so as to free said other shaft for axial movement in said one predetermined axial direction.