AU2007221906B1

AU2007221906B1 - Control System for A Grasping Instrument

Info

Publication number: AU2007221906B1
Application number: AU2007221906A
Authority: AU
Inventors: John Silady
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-10-09
Filing date: 2007-10-09
Publication date: 2008-10-23
Anticipated expiration: 2027-10-09
Also published as: WO2009046490A1

Description

9 .0ct. 2007 21:58 No. 1765 F. 3 P/00/009

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION Invention Title: CONTROL SYSTEM FOR A GRASPING INSTRUMENT The invention is described in the following statement together with the best method of performing it known to us: Our Ref: 072030 COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9. Oct. 2007 21:59 No. 1765 P. 4 2 SCONTROL SYSTEM FOR A GRASPING INSTRUMENT The present invention relates to devices for grasping 0 0 and holding and, more particularly, to control mechanisms o for such devices.

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BACKGROUND

Ci One preferred application of the present invention is o in the field of laparoscopic surgery. Laparoscopic surgical Ci procedures include the cutting, holding and cauterising of tissue. For these purposes a wide range of instruments have been devised operable at the end of an elongate shaft or flexible hollow member. A surgeon is able to activate the instrument at the end of the shaft by a mechanism graspable by the thumb and fingers in a manner similar to the operation of scissors.

The instrument at the end of the rod, which may take various forms including small cutters and holding jaws or forceps, are very small and easily damaged if excessive force is applied to the pivot pins and other components by the grasping action of the surgeon.

Another problem which must be addressed is that in the case of holding or clamping of tissue, the force applied should not be excessive, regardless of the degree of closure of the graspable mechanism in the hand of the operator. For these operations also, it is desirable that the mechanism can be locked at a desired intermediate or COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9, Oct. 2007 21:59 NVo. 1765 P. 3 maximum available clamping force, while at the same time providing that this clamping force can be instantly released without any further significant increase in the force applied to the tissue being held.

Still a further problem is that the instrument must be capable of being rapidly disengaged from the controlling mechanism so that an alternative instrument can be quickly attached.

Although these problems are identified in relation to laparoscopic surgery, they apply to other applications in which a delicate object needs be grasped with restricted force, and held securely until released.

It is an object of the present invention to address or at least ameliorate some of the above disadvantages.

Notes 1. The term "comprising" (and grammatical variations thereof) is used in this specification in the inclusive sense of "having" or "including", and not in the exclusive sense of "consisting only of".

2. The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.

3. Note, the terms "proximate" and "distal" as used in this specification refer to the relationship of a described COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 7. Oct, 2008 12:11 WALLINGTON-DUMMER No. 6093 P. 4 00 0 feature relative to the working end of an C attached surgical or grasping instrument.

0 o BRIEF DESCRIPTION OF INVENTION \0 SAccordingly, in a first broad form of the invention, there is provided a grasping instrument control mechanism said 0g instrument including opposing jaws (16) at an end of an elongate hollow member said mechanism including a rotatable operating handle (34) acting on a jaws activating element (18); characterized in that said rotatable operating handle (34) includes an arc of pinion teeth centred on the centre of rotation of said operating handle said pinion teeth engaging with a rack of teeth (58) along a portion of a cylindrical spring-retaining body (42) communicating with said jaws activating element said cylindrical spring-retaining body (42) urged into a retracted position by rotation of said operating handle (34) from a non-operating position towards an operating position proximate a fixed handle wherein rotation of said operating handle (34) past a point of resistance to further closure of said COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7. Oct. 2008 12:11 WALLINGTON-DUMMER No. 6093 P. 6 00 0 opposing jaws (16) causes partial compression of a compression spring (50) within said cylindrical o spring-retaining body (42) without substantial Sfurther closure of said opposing jaws (16).

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Preferably, said mechanism is secured within ci a housing a base portion (24) of said o housing (22) integral with said fixed handle said operating handle (34) rotatable about a pivot (32) provided in said base portion (24); said operating handle (34) rotatable between a position maximally distal from said fixed handle (28) and a position proximate said fixed handle said operating handle passing through said non-operating position.

Preferably, said cylindrical springretaining body (42) and a cylindrical pawlretaining body (44) are slidingly located in a bore of an outer cylindrical body said outer cylindrical body (38) fixed within said base portion (24).

COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7. Oct. 2008 12:11 WALLINGTON-DUMMER No. 6093 P. 7 6 00 O0 0 Preferably, said cylindrical pawl-retaining body (44) includes a spring compression rod (46) o extending from a distal end of said cylindrical Spawl-retaining body said compression spring (50) retained in said cylindrical spring- \0O Sretaining body (42) between an annular shoulder C- (52) at a proximate end of said spring-retaining 0' body (42) and a spring compression nut (48) 0- engaged with a threaded portion of said spring compression rod said spring compression rod (46) extending into, and through substantially the length of said cylindrical spring-retaining body (42).

Preferably, said cylindrical springretaining body (42) abuts said cylindrical pawlretaining body (44) when said operating handle (34) is in said non-operating position; said compression spring (50) then being in a minimum compressed state.

Preferably, an opposing pair of pawls (54) (55) are retained in a longitudinal slot (49) provided in said cylindrical pawl-retaining body COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7-ct. 2008 12:11 WALLINGTON-DUMMER No. 6093 P. 8 7 00 0 said pawls (54) (55) shaped at respective proximate ends as jaws so as to. close on a ball- 0 0 end (56) of said jaws activating element (18); O said pawls (54)(55) shaped at respective distal ends to allow symmetrical rotation of one pawl

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Srelative to the other between a closed retaining -position on said ball-end and an open S disengaging position.

Preferably, said outer cylindrical body (38) is provided with a counterbore (63) at a proximate end of said outer cylindrical body; said counterbore (63) arranged to allow partial protrusion of said opposing pair of pawls (54) (55) from said slot said protrusion enabled when said proximate ends of said pawls (54)(55) are brought into coincidence with said counterbore (63) by rotation of said operating handle (34) into a position maximally distal from said fixed handle said pawls (54) rotated into a protruding position through contact of Said ball-end of said jaws activating element (18) moving into said proximal direction for disassembly of said instrument (12) from said control mechanism COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7-Oct. 2008 12:12 WALLINGTON-DUMMER No, 6093 P. 9 8 00 o Preferably, said opposing pair of pawls S(54)(55) are constrained in said closed retaining 0 O position when said cylindrical pawl-retaining o body (44) is retracted wholly within said bore of said outer cylindrical body (38) by partial

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C rotation of said operating handle (34) towards Cl said fixed handle said pawls (54)(55) then Cl Sclosed on said ball end of said jaws activating Cl element (18) when said instrument is assembled to said control mechanism.

Preferably, said mechanism further includes a locking lever (82) for releasably retaining said operating handle (34) in a desired operating position in which resistance to further closure of said jaws (16) is accompanied by a degree of compression of said compression spring said locking lever (82) including first and second teeth (84A) (84B) for engagement with an arc of locking teeth (64) of said operating handle (34).

Preferably, said arc of pinion teeth and said arc of locking teeth (64) are substantially arranged at opposing sides of said COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7. Oct. 2008 12:12 WALLINGTON-DUMMER No. 6093 P. 9 00 0 operating handle (34) and substantially Sdiametrically opposed about said centre of 0 0 rotation of said operating handle said O locking lever (82) projecting from said housing (22) at a side of said fixed handle (28) distal

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from said operating handle said lever (82) Ci arranged for depressing in a direction of said S fixed handle (28) by a finger of the hand of a C user.

Preferably, said locking lever (82) is an extension of a locking lever plate said locking lever (82) and said locking lever plate (83) rotating about a pivot (86) provided in said base portion (24) of said housing said locking lever (82) and locking lever plate (83) biased towards a non-locking position by a spring loaded ball (90) engaging with a hole (88) in said locking lever plate.

Preferably, teeth of said arc of locking teeth (64) of said operating handle (34) are set at angles with respect to radii at respective ones of said teeth; said angles such that said COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7.ct. 2008 12:12 WALLINGTON-DUMMER No. 6093 P. 11 teeth point in a direction opposite to said rotation of said operating handle (34) towards said position proximate said fixed handle (28).

Preferably, said first and second teeth (84A) (84B) project from said locking lever plate said first and second teeth generally angled in an opposite direction to said angles of said teeth of said arc of locking teeth (64) of said operating handle (34).

Preferably, a first tooth of said first and second teeth is located at greater remove from said pivot (32) of said locking plate than the second tooth of said first and second teeth.

Preferably, said jaws (16) are locked in a said desired operating position by the steps of: applying pressure to (34) to compression spring, sufficient additional said operating handle induce said partial of said compression COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7. Oct. 2008 12:12 WALLINGTON-DUMMER No. 6093 P. 12 11 00 O simultaneously moving said locking lever (82) towards said fixed handle 0 0 (28) 0 releasing pressure on said operating VD 5 handle (34), 0 C- releasing pressure on said locking l lever (82), 0 said movement of said locking lever (82) towards said fixed handle (28) rotating said first and second teeth (84A) (84B) into meshing engagement with teeth of said arc of locking teeth and wherein relative angles of said first tooth (84A) and meshing teeth of said arc of locking teeth, act to lock said first tooth into locked engagement with said meshing teeth by bias of said operating handle (34) to return said operating handle to said non-operating position due to said partial compression of said compression spring Preferably, said second tooth (84B) acts to release said locking position of said locking lever relative angles of said second tooth COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7. Oct. 2008 12:12 WALL1NGTON-DUMMER No. 6093 P. 13 12 00 o and teeth of said arc of locking teeth arranged such that slight rotation of said operating O handle (34) towards said fixed handle (28) by Sslight renewed pressure on said operating handle acts to release engagement between said

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Sfirst tooth (84A) and said meshing teeth of said C-i arc of locking teeth said spring-loaded ci S ball (90) then acting to return said locking C-i lever (82) to said non-locking position.

Preferably, a said instrument (12) is detachably connected to said control mechanism by an instrument connector element (65) at a proximal end of said mechanism; said connector element comprising an externally threaded cylindrical body said cylindrical body integral with a disc (68) provided with a finger graspable periphery; said cylindrical body and said disc rotatable around a proximate end portion (40) of said outer cylindrical body (38); said proximate end portion projecting from said housing (22).

COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7-Oc. 2008 12:12 WALLINGTON-DUMMER No. 6093 F. 14 13 00 O0 0 Preferably, a distal end of said elongate hollow member (14) of a said surgical instrument 0 O (12) is provided with a captive nut (69) for Sthreaded engagement with said externally threaded cylindrical body said distal end provided

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Swith a skirt (70) locating within said nut (69); r- said skirt clamped to a proximate face (72) of S said outer cylindrical body (38) when said Cq captive nut is maximally advanced on said externally threaded cylindrical body, the arrangement being such that said instrument may be rotated 360 degrees relative said control mechanism by means of said finger graspable periphery.

Preferably, said operating handle (134) includes an arcuate segment (164) diametrically opposite said arc of pinion teeth (160); said mechanism including a conductive path for the transmission of high frequency electric currents for use in diathermy procedures; said path including a cable connector (102) extending from said fixed handle (128) and a spring-loaded conductive rod (106) in contact with an arcuate edge of said arcuate segment (164).

COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 71. Oct. 2008 12:12 WALLINGTON-DUMMER No, 6093 P. 14 00 0 0 c, o In another broad for of the invention, there is 0 provided a method for applying an operating force to a grasping instrument; said force limited so \O 5 as to prevent damage to said instrument from ^O excessive force applied by a user; said method including the steps of: C interposing a spring mechanism between an operating handle of a control mechanism of said instrument and a jaw activating element, arranging wire diameter and number of coils of a spring of said spring mechanism said such that said spring does not reach full compression when said operating handle is rotated to a maximum operating position and past a point of resistance to further closure of opposing jaws of said instrument, wherein said spring mechanism includes a spring-retaining cylindrical body; a rack of teeth along a portion of said spring-retaining body meshing with teeth of an arc of pinion COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7-ct. 2008 12:12 WALLINGTON-DUMMER No. 6093 P. teeth of an operating handle of said- control mechanism.

COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 9, Oct. 2007 22:02 No. 1765 P. 18 16 o BRIEF DESCRIPTION OF DRAWINGS SEmbodiments of the present invention will now be 0 o described with reference to the accompanying drawings o wherein; Figure 1 is a side view of a control mechanism, for a grasping instrument according to a first preferred embodiment of the invention, showing an instrument control Smechanism with an example of an attachable surgical

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instrument, Figure 2 is a side view of the control mechanism with the surgical instrument attached, Figure 3 is a sectioned side view of the control mechanism and surgical instrument of Figure 1 with a surgical instrument in a detached position, Figure 3B is an enlargement of a portion of the mechanism of Figure 3, Figure 4 is a sectioned side view of the control mechanism and surgical instrument of Figure 1 with the surgical instrument attached but in a non-activated state, Figure 4B is an enlargement of a portion of the mechanism of Figure 4, Figure 4C is a further enlargement of portion of Figure 4B, Figure 5 is a sectioned side view of the control mechanism and surgical instrument of Figure 1 with the surgical instrument attached in an activated, locked state, COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9. Oct. 2007 22:02 No. 1765 P. 19 17 o Figure 5B is an enlargement of a portion of the mechanism of Figure O Figures 6A to 6B are enlarged sectioned side views and o end views of portions of the mechanism of Figures 1 to Figure 7 is a side view of a second preferred embodiment of diathermy instrument control mechanism C according to the invention, SFigure 8 is a sectioned side view of the diathermy 0 C control mechanism of Figure 7.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS First Preferred Embodiment With reference to Figure 1 to 3, in a first preferred application of the present invention, control mechanism according to the invention, comprises a control mechanism 11 to which may be attached for example, any one of a number of surgical instruments for grasping, cutting and cauterizing tissue. An example of such a surgical instrument 12 comprises an elongate hollow member or shaft 14 (as best seen in Figure at the end of which is the active surgical instrument tool 16 (in this example a pair of grasping forceps). For grasping and cutting operations, the instrument is activated by applying retractive force to an inelastic tool activating element, in this instance an activating rod 18 extending from the instrument tool mechanism 20 through shaft 14. This retractive force causes COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9. Oct. 2007 22:02 1765 P. 18 o the tool 16 to change from an inactive state to an Sactivated state.

0 0 Control mechanism 11 comprises a housing 22 made up of o a base portion 24 and a cover portion 26. Integrally formed with base portion 24, is a fixed handle 28 extending from base portion 24 and ending in a scissor-like ring 30 for C insertion of at least one finger of the hand of a user (not o shown).

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Referring now particularly to Figures 3 and 3B, base portion 24 is provided with a pivot 32 about which an operating handle 34 can rotate from a position proximate fixed handle 28 (as shown in Figure 2) and a position maximally distal from fixed handle 28 (as shown in Figure and passing through an intermediate non-operating position (as shown in Figure Operating handle 34 is likewise provided with a scissor-like ring 36 for insertion of the thumb of a user, so that the two handles may be operated with the one hand in similar fashion to the manner of use of a pair of scissors.

Mounted rigidly to base portion 24, is an outer cylindrical body 38, with a proximate end portion projecting from the proximate end of the base portion 24.

Slidingly located within the bore of outer cylindrical body 38 are a cylindrical spring-retaining body 42 and a cylindrical pawl-retaining body 44. (These features are more clearly shown in the enlarged detail views of Figures COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9.Oct. 2007 22:02 No. 1765 P. 21 19 o6A to 6C). Attached at the distal end of pawl-retaining Sbody 44 is a spring compression rod 46 extending into, and O substantially the length of spring-retaining body 42, when 0the distal end of pawl-retaining body 44 abuts the \O 5 proximate end of spring-retaining body 42 (as shown in ON Figure 6A). Spring compression rod 46 is threaded at its CN distal end and provided with a spring compression nut 48. A Scompression spring 50 is retained between compression nut 48 and annular shoulder 52 at the proximate end of the cylindrical spring-retaining body 42.

Cylindrical pawl-retaining body 44 is provided with a longitudinal slot 49. Retained within longitudinal slot 49 are opposing pawls 54 and 55 shaped at their proximate ends as jaws to close on a ball end 56 of the inelastic activating rod 18. As best seen in the enlarged views of Figures 6A to 6C, the distal ends of pawls 54 and 55 are shaped so as to allow rotation one against the other between the open position of Figure 6A and the closed positions of Figures 6B and 6C.

Note that this rotation of the pawls is effected without the need for pivot pins or the like; the pawls are loose within the slot and are restrained by the outer cylindrical body 38 and the counterbore 63 at the proximate end 40 of body 38.

Still with reference to Figures 6A to 6C as well as Figure 3, a side of the distal end of cylindrical spring- COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9. Oct. 2007 22:02 No. 1765 P. 22 20 0 Sretaining body 42 is machined to provide a toothed rack 58 Swhich engages with an arc of pinion teeth 60. Arc of pinion O teeth 60 is part of a toothed plate 62 rigidly attached to o operating handle 34, and provided with a hole 33 for pivot 32. Also part of toothed plate 62 is an arc of locking Steeth 64, substantially diametrically opposite to the arc

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of pinion teeth 60, with both arcs of teeth centred on Spivot 32.

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It will be understood that, with rotation of operating handle 34 about pivot 32 in the proximate, or operating direction (that is towards fixed handle 28), pinion teeth meshing with toothed rack 58 will retract the cylindrical spring-retaining body 42 in the distal direction as can be seen in Figures 4, 5 and 6C. Similarly, if operating handle 34 is rotated in the distal, or nonoperating, direction away from fixed handle 28, cylindrical spring-retaining body will be advanced in the proximate direction as can be seen in Figures 3 and 6A.

When operating handle 34 is in the maximum distal, non-operating position of Figure 3 or 6A, the cylindrical spring-retaining body 42 and cylindrical pawl-retaining body 44 are sufficiently advanced towards the proximate end of outer cylindrical body 38, for the proximate ends of pawls 54 and 55 to coincide with the counterbore 63 at the proximate end of the outer body (see Figure 6A). In this position, the pawls 54 and 55 can be forced by ball end 56 COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9, Oct. 2007 22:03 No. 1765 P. 23 21 Sto rotate relative to each other to the open position shown in Figures 3 and 6A, as, in this instance, the surgical 0 O instrument is pulled away from the control mechanism.

oReferring again to Figures 1 to 3, control mechanism 11 is provided with an instrument connector element comprises an externally threaded cylindrical body 66.

Cylindrical body 66 is integral with a disc 68 provided o with a finger graspable periphery. The cylindrical body and the disc are rotatable around the proximate end portion of the outer cylindrical body 38 projecting from housing 22.

Each instrument 12 which may be attached to the control mechanism 11, is provided with a captive nut 69 at the distal end of elongate hollow shaft 14, for threaded engagement with the external thread of the instrument connector element 65. The distal end of elongate hollow shaft 14 is provided with a skirt 70 arranged for clamping to a proximate face 72 of the externally threaded cylindrical body 66. By this means, with skirt 70 locked against the instrument connector element 65 by captive nut 69, the complete instrument may be rotated 360 degrees about the shaft axis relative to the control mechanism 11.

Initial retraction of cylindrical pawl-retaining body 44 will force pawls 54 and 55 into the closed position shown in Figures 4, 5, and 6B, as the pawls are withdrawn into the main bore of outer cylindrical body 38. As the COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 0 t. 2007 22:03 No. 1765 P. 24 22 Spawls are retracted further, the ball end 56 and inelastic ci Sactivating rod 18 are also retracted.

0 O It will be understood, that as long as the inelastic o activating rod 18 remains free to move in the distal 5 direction (as shown by the arrows of Figure 6B),

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cylindrical pawl-retaining body 44 will move in unison with cylindrical spring-retaining body 42 (as shown in Figures 4 o and 6B). However, when the instrument 16 closes onto a s portion of tissue, or some other item (as shown in Figure further movement of activating rod 18 will be resisted to the extent dependent on the nature of the tissue or item. At some point the resistance to further movement of the activating rod 18 becomes such that the installed spring force of spring 50 is exceeded and while cylindrical spring-retaining body 42 may be urged to continue movement to its maximum retraction within housing 22, the actual force applied to the tissue will be modulated by spring as can be seen in Figure 6C.

The maximum travel of cylindrical spring-retaining body 42 in the distal direction, the wire diameter and number of coils of spring 50 are arranged so that spring cannot reach full compression. Thus the maximum force applied to activating rod 18 is limited to the maximum exerted by spring 50 when at a maximum predetermined compression, even up to the point where operating handle 34 comes into contact with fixed handle 28. Before this point COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9. Oct. 2007 22:03 lo. 1765 P. 23 0 o is reached a scissor cutting tool or grasping forceps of an ci c attached surgical instrument for example, will have reached 0 O its limit of closure, but since the force never exceeds the o maximum predetermined by the spring at it maximum permitted O 5 compression, damage to instrument tools (or to delicate tissue or other items) is prevented.

C' For many procedures using forceps such as the example cqs oshown in Figures 1 to 5, or other grasping devices, it is desirable that a desired degree of clamping on a portion of tissue or item be maintained. For this purpose the control mechanism 11 of this embodiment of the invention is provided with a locking mechanism 80 as shown in Figures 3 to 5. Locking mechanism 80 is arranged to hold the operating handle 34 in any of a number of possible incremental positions in which some compressive force has been applied to spring 50 as a result the of retraction of cylindrical spring-retaining body 42; that is, by the rotation of operating handle 34 in the proximate, or operating direction. It will be understood that when such a force (greater than the minimum installed spring force) is present, spring 50 will act to urge contra-rotation of operating handle 34 towards the distal position.

The locking mechanism 80 provides interaction between locking teeth 84 of a locking lever 82 and the arc of locking teeth 64 provided on the toothed plate 62 described above. As can best be seen in the enlarged views of Figures COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9. Oct. 2007 22:03 No. 1765 P. 26 24 3B, 4B, 4C and 5B, locking lever 82 includes a locking ci Slever plate 83 provided with first and second locking teeth o 84A and 84B. Locking lever plate 83 and locking lever 82 0pivot about locking lever pivot 86 between the unlocked NO 5 position shown in Figures 3B and 4B, the intermediate §O engaging position of Figure 4C, and the locked position of (c Figures 4C and SThe teeth of the arc of locking teeth 64, are set at 0 angles with respect to radii at respective ones of the teeth, such that the teeth point in a direction opposite to the rotation of the operating handle 34 for applying compressive force to spring 50, that is, towards fixed handle 28. The pair of locking teeth 84A and 84B of locking lever 82 are also angled but in the opposite direction. It can be seen from a comparison of Figures 4B, 4C and that a first depressing of the locking lever 82 into the locking position of Figure 5B, brings the locking teeth 84A and 84B projecting from locking lever plate 83, into meshing engagement with the arc of locking teeth 64.

It should be noted that the leading edges of teeth 84A and 84B are set at different angles. This is partly to accommodate the angular difference of the locking teeth 64 with which these two teeth mesh, but also because they are functionally distinct, with tooth 84A being the active tooth in establishing the locking engagement of the teeth, and tooth 84B being active in disengagement.

COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9, Oct. 2007 22:04 No. 1765 P. 27 25 o As best understood from the enlarged view of Figure t 4C, the leading edge of first tooth 84A (which is at O greater remove from pivot 86) and the leading edge of a otooth of the arc of locking teeth 64 with which it engages, are both at the same angle relative the rotation centres of pivot 86 of locking lever plate 83 and pivot 32 of toothed plate 62. This angle is such that the biased tendency of o the operating lever to contra-rotate towards the distal 0

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position, acts to pull tooth 84B into the maximum meshed position shown in Figure This meshing is initiated by a user, having applied the desired clamping force to an item such as a piece of tissue for example, pulls the locking lever in towards the fixed handle 28, and immediately releases the force he or she is applying to the operating handle 34.

This meshing engagement of the locking teeth 64 with the locking tooth 84A of the locking lever 82, is retained in the locked state when the operating lever 34 is in an operating position, because the operating lever is biased toward contra-rotation into a non-operating position by the force of spring Base portion 24 of housing 22 is provided with a spring-loaded ball 90, which is biased towards partly protruding from an inside surface 92 of the base portion 24. The protrusion of ball 90 varies with the locking and COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9. Oct. 2G07 22:04 No. 1765 P. 28 26 o non-locking positions of locking lever 82, with the ball in ci Sa maximum protruded state when the locking lever is in the -O non-locking position shown in Figures 3, 3B, 4 and 4B. The 0 arrangement is shown in the enlargements of Figures 3B, 4B kN 5 and 4C. Locking lever plate 83 is provided with a springloaded ball engaging element, which in this instance is a C hole 88 through the plate. Hole 88 is arranged so that the Sspring-loaded ball 90 biases the hole (and thus the locking Slever plate and lever) into the non-locking position in which the hole is centred on the ball (as is the situation in Figures 3, 3B, 4 and 4B).

To release operating lever 34 from its locked state, only a very slight renewed pressure is required on the operating handle 34, that is a very light squeezing pressure between the thumb and fingers of a user. It is by this action that the locking lever second tooth 84B becomes the active component. Again with reference to Figure 4C, it can be seen that the abutting of the trailing edge of tooth 84B and the trailing edge of the tooth of the arc of locking teeth 64 with which it meshes, that the slightest rotation applied to the operating handle (in the direction opposite the arrow on plate 62; that is towards the fixed handle), will induce a very small degree of rotation of locking lever plate 83 (in the direction opposite to the arrow on the plate 83 in Figure 4C). This is sufficient to COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9. Oct. 2007 22:04 No. 1765 P. 29 27 o release the engagement between the leading edges of tooth S84A and its corresponding tooth of the arc of locking 0 O teeth. This is enough for the spring-loaded ball 90 to o immediately urge locking lever 82 back into its default 5 unlocked position.

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SIn Use In use, a user is able to apply a desired closing force to the tool of a surgical instrument for example without risk of damage to the instrument, or to some fragile item such as tissue. In the case of forceps, a desired clamping force can be instantly retained by the relatively short throw of the locking lever, and almost instantly released by applying an insignificant brief additional pressure to the operating handle when in the locking position. As well, any of a number of interchangeable tools for cutting and gripping tissue or other items may be rapidly attached and detached by means of the novel pawl mechanism incorporated in the control mechanism.

It should be noted that although the above description is focused on an instrument incorporating a shaft with an inelastic rod operating within that shaft, the principles of force modulation by the spring mechanism and of the COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9. Oct. 2007 22:04 N0 1765 P. 28 o operating handle locking/unlocking mechanism can be equally Sapplied to a flexible sheath with internal inelastic cable O (a Bowden cable) for operating a flexible instrument.

0\ Again, it will be understood that although the above o 5 description of the grasping control mechanism is directed primarily at surgical instruments, the principles of providing a spring modulated force and grasping locking o mechanism of the invention can clearly be applied to a ci range instruments or tools for grasping and holding delicate items- Second Preferred Embodiment In a second preferred embodiment and application of the invention, elements of the control mechanism described above are adapted to a control mechanism for diathermy endoscopic procedures.

With reference to Figure 7, a diathermy laparoscopic control mechanism 100 again comprises a control mechanism 110 to which may be attached any one of a range of endoscopic surgical instruments such as the surgical instrument 112 with forceps 116 shown in Figure 7. As can be seen in Figure 8, surgical instrument 112 is identical to the exemplary surgical instrument 12 shown for the first embodiment above and is attached to the control mechanism COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9, Oct. 2007 22:04 No. 1765 P. 31 29 0 o 110 and activated in precisely the same manner as cN previously described.

0 Thus in this embodiment also, the force provided for a procedure at the tool (forceps 116 in this instance) is o 5 modulated and limited by the spring-loaded mechanism described in detail above.

ci ci o For transmission of the high frequency electric CA currents used in diathermy procedures, the control mechanism 110 of this embodiment is provided with a cable connector 102 projecting from fixed handle 128. Current is passed via compression spring 104 to conductive rod 106.

Inner tip 107 of conductive rod 106 is urged into conducting contact with toothed plate 162, affixed to operating handle 134. In this embodiment toothed plate 162 is provided with a smooth arcuate edge 164 substantially diametrically opposite the arc of teeth 160.

Base portion 124, fixed handle 128, operating handle 134 the surgical instrument connector element* 165 as well as the elongate hollow shaft 114 of the instrument are all formed of non-conductive insulating material. However, toothed plate 162 is conductive so that the conductive path between cable connector 102 and the tool of the surgical instrument is completed via toothed plate 162, cylindrical spring-retaining body 142 and spring 150, the cylindrical COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9, Oct. 2007 22:05 No. 1765 P. 32 30 0 Spawl-retaining body 144, pawls 154 and 155 and activating ci Srod 118.

0 In both the embodiments described above, the base portion and cover portion of the housing for the control o 5 mechanism may be fastened together by at least one, preferably two fasteners as can be seen in Figures 1, 2 and 7. Preferably these fasteners are arranged to allow Stightening only with a suitable tool, and are resistant to unscrewing.

As can be seen in the inset of Figure 7, a threaded fastener 119 is includes a head portion 120 in which is provided at least a pair of elongated arcuate slots 121 in an outer surface of the head portion. Each of these slots 121 is shaped at one side with a ramped surface 122 extending from the outer surface of the head portion to the bottom 123 of the slot, and shaped at the other side with a surface substantially normal to the outer surface. Thus the slots allow the insertion of a driving tool with projecting pins, which when rotated against the surfaces normal to the outer surface of the head portion urge the fastener to rotate, but when rotated in the opposite direction force the tool to disengage without inducing rotation.

COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09 9, Oct. 2007 22:05 No. 1765 P. 33 31 o The above describes only some embodiments of the Spresent invention and modifications, obvious to those O skilled in the art, can be made thereto without departing 0 from the scope of the present invention.

O

0 0 0 COMS ID No: ARCS-164130 Received by IP Australia: Time 22:12 Date 2007-10-09

Claims

7. Oct. 2008 12:12 WALLINGTON-DUMMER No. 6093 P. 17 0oO CLAIMS 0 0 0 instrument including opposing jaws (16) at an end of IO an elongate hollow member said mechanism 0 Sincluding a rotatable operating handle (34) acting on Ci a jaws activating element characterized in that O said rotatable operating handle (34) includes an arc of pinion teeth (60) centred on the centre of rotation of said operating handle said pinion teeth engaging with a rack of teeth (58) along a portion of a cylindrical spring-retaining body (42) communicating with said jaws activating element said cylindrical spring-retaining body (42) urged into a retracted position by rotation of said operating handle (34) from a non-operating position towards an operating position proximate a fixed handle (28), wherein rotation of said operating handle (34) past a point of resistance to further closure of said opposing jaws (16) causes partial compression of a compression spring (50) within said cylindrical spring-retaining body (42) without substantial further closure of said' opposing jaws (16). COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7-Oct. 2008 12:10J WALLINGTON-DUMMER No. 6093 P. 18 C0 33 (N 2. The mechanism of claim 1 wherein said mechanism is 0 O secured within a housing a base portion (24) of o said housing (22) integral with said fixed handle said operating handle (34) rotatable about a VO Spivot (32) provided in said base portion said Cq operating handle (34) rotatable between a position Smaximally distal from said fixed handle (28) and a C- position proximate said fixed handle said operating handle passing through said non-operating position. 3. The mechanism of claim 2 wherein said cylindrical spring-retaining body (42) and a cylindrical pawl- retaining body (44) are slidingly located in a bore of an outer cylindrical body said outer cylindrical body (38) fixed within said base portion (24). 4. The mechanism of claim 3 wherein said cylindrical pawl-retaining body (44) includes a spring compression rod (46) extending from a distal end of said cylindrical pawl-retaining body said compression spring (50) retained in said cylindrical spring- retaining body (42) between an annular shoulder (52) at a proximate end of said spring-retaining body (42) and a spring compression nut (48) engaged with a COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7.ct, 2008 12:10J WALLINGTON-DUMMER No, 6093 P. 19 0 34 0 (N threaded portion of said spring compression rod (46); 0 0 said spring compression rod (46) extending into, and 0 through substantially the length of said cylindrical spring-retaining body (42). NO VD 5. The mechanism of any one of claims 2 to 4 wherein said ci Cl cylindrical spring-retaining body (42) abuts said O cylindrical pawl-retaining body (44) when said operating handle (34) is in said non-operating position; said compression spring (50) then being in a minimum compressed state. 6. The mechanism of any one of claims 2 to 5 wherein an opposing pair of pawls (54) (55) are retained in a longitudinal slot (49) provided in said cylindrical pawl-retaining body said pawls (54) (55) shaped at respective proximate ends as jaws so as to close on a ball-end (56) of said jaws activating element (18); said pawls (54) (55) shaped at respective distal ends to allow symmetrical rotation of one pawl relative to the other between a closed retaining position on said ball-end and an open disengaging position. 7. The mechanism of claim 6 wherein said outer cylindrical body (38) is provided with a counterbore (63) at a proximate end of said outer cylindrical COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7. Oct. 2008 12:13 WALLINGTON-DUMMER No. 6093 P. oO 00 body; said counterbore (63) arranged to allow partial 0 0 protrusion of said opposing pair of pawls (54) o from said slot said protrusion enabled when said proximate ends of said pawls (54)(55) are brought into VO Scoincidence with said counterbore (63) by rotation of said operating handle (34) into a position maximally distal from said fixed handle said pawls 0- (54) (55) rotated into a protruding position through contact of said ball-end of said jaws activating element (18) moving into said proximal direction for disassembly of said instrument (12) from said control mechanism
8. The mechanism of claim 6 or 7 wherein said opposing pair of pawls (54) (55) are constrained in said closed retaining position when said cylindrical pawl- retaining body (44) is retracted wholly within said bore of said outer cylindrical body (38) by partial rotation of said operating handle (34) towards said fixed handle said pawls (54)(55) then closed on said ball end of said jaws activating element (18) when said instrument is assembled to said control mechanism. COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7.Oct. 2008 12:13 WALLINGTON-DUMMER No. 6093 P. 21 oO 00 36 c_ 9. The mechanism of any one of claims 1 to 8 wherein said 0 O mechanism further includes a locking lever (82) for 0 releasably retaining said operating handle (34) in a desired operating position in which resistance to VO Sfurther closure of said jaws (16) is accompanied by a Clq degree of compression of said compression spring ci said locking lever (82) including first and second pC teeth (84A) (84B) for engagement with an arc of locking teeth (64) of said operating handle (34). The mechanism of claim 9 wherein said arc of pinion teeth (60) and said arc of locking teeth (64) are substantially arranged at opposing sides of said operating handle (34) and substantially diametrically opposed about said centre of rotation of said operating handle said locking lever (82) projecting from said housing (22) at a side of said fixed handle (28) distal from said operating handle said lever (82) arranged for depressing in a direction of said fixed handle (28) by a finger of the hand of a user.
11. The mechanism of claim 9 or 10 wherein said locking lever (82) is an extension of a locking lever plate said locking lever (82) and said locking lever COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7. Oct. 2008 12:13 WALLINGTON-DUMMER No. 6093 P. 22 00 0 37 plate (83) rotating about a pivot (86) provided in O said base portion (24) of said housing said o locking lever (82) and locking lever plate (83) biased towards a non-locking position by a spring loaded ball NO engaging with a hole (88) in said locking lever (C plate.
12. The mechanism of any one of claims 9 to 11 wherein ci teeth of said arc of locking teeth (64) of said operating handle (34) are set at angles with respect to radii at respective ones of said teeth; said angles such that said teeth point in a direction opposite to said rotation of said operating handle (34) towards said position proximate said fixed handle (28).
13. The mechanism of claim 11 or 12 wherein said first and second teeth (84A)(84B) project from said locking lever plate said first and second teeth generally angled in an opposite direction to said angles of said teeth of said arc of locking teeth (64) of said operating handle (34).
14. The mechanism of any one of claims 9 to 13 wherein a first tooth of said first and second teeth is located at greater remove from said pivot (32) of said locking COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7. Oct. 2008 12:13 WALLINGTON-DUMMER No. 6093 P. 23 0oo S38 plate than the second tooth of said first and second 0 teeth. The mechanism of any one of claims 9 to 14 wherein NO said jaws (16) are locked in a said desired operating O_ position by the steps of: a- applying sufficient additional pressure to said 0 operating handle (34) to induce said partial compression of said compression spring, b. simultaneously moving said locking lever (82) towards said fixed handle (28) c. releasing pressure on said operating handle (34), d. releasing pressure on said locking lever (82), said movement of said locking lever (82) towards said fixed handle (28) rotating said first and second teeth (84A)(84B) into meshing engagement with teeth of said arc of locking teeth and wherein relative angles of said first tooth (84A) and meshing teeth of said arc of locking teeth, act to lock said first tooth into locked engagement with said meshing teeth by bias of said operating handle COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7. Oct. 2008 12:13 WALLINGTON-DUMMER No. 6093 P. 24 o0 i39 c- (34) to return said operating handle to said non- 0 operating position due to said partial compression o of said compression spring \0 16. The mechanism of claim 15 wherein said second tooth (84B) acts to release said locking position of said ci Cl locking lever relative angles of said second Stooth and teeth of said arc of locking teeth arranged such that slight rotation of said operating handle (34) towards said fixed handle (28) by slight renewed pressure on said operating handle acts to release engagement between said first tooth (84A) and said meshing teeth of said arc of locking teeth (64); said spring-loaded ball (90) then acting to return said locking lever (82) to said non-locking position.
17. The mechanism of any one of claims 3 to 8 wherein a said instrument (12) is detachably connected to said control mechanism by an instrument connector element at a proximal end of said mechanism; said connector element comprising an externally threaded cylindrical body said cylindrical body integral with a disc (68) provided with a finger graspable periphery; said cylindrical body and said disc rotatable around a proximate end portion (40) of said COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7, Oct. 2008 12:13 WALLINGTON-DUMMER No. 6093 P. 0 0 outer cylindrical body said proximate end 0 O portion projecting from said housing (22).
18. The mechanism of claim 17 wherein a distal end of said 0 elongate hollow member (14) of a said surgical Sinstrument (12) is provided with a captive nut (69) Ci for threaded engagement with said externally threaded Scylindrical body said distal end provided with a skirt (70) locating within said nut said skirt clamped to a proximate face (72) of said outer cylindrical body (38) when said captive nut is maximally advanced on said externally threaded cylindrical body, the arrangement being such that said instrument may be rotated 360 degrees relative said control mechanism by means of said finger graspable periphery.
19. The mechanism of claim 17 or 18 wherein said operating handle (134) includes an arcuate segment (164) diametrically opposite said arc of pinion teeth (160); said mechanism including a conductive path for the transmission of high frequency electric currents for use in diathermy procedures; said path including a cable connector (102) extending from said fixed handle (128) and a spring-loaded conductive rod (106) in COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07 7.Oct. 2008 12:14 WALLINGTON-DUMMER No. 6093 P. 26 o0 00 41 0 contact with an arcuate edge of said arcuate segment 0 O (164). 0 A method for applying an operating force to a grasping OD instrument; said force limited so as to prevent damage 0 *O to said instrument from excessive force applied by a C user; said method including the steps of: S(a) interposing a spring mechanism between an operating handle of a control mechanism of said instrument and a jaw activating element, arranging wire diameter and number of coils of a spring of said spring mechanism said such that said spring does not reach full compression when said operating handle is rotated to a maximum operating position and past a point of resistance to further closure of opposing jaws of said instrument, wherein said spring mechanism includes a spring-retaining cylindrical body; a rack of teeth along a portion of said spring-retaining body meshing with teeth of an arc of pinion teeth of an operating handle of said control mechanism. COMS ID No: ARCS-208787 Received by IP Australia: Time 13:17 Date 2008-10-07