Surgical tool mechanism

1. A surgical tool comprising a longitudinally extending support means defining a longitudinal axis of said tool, an elongate center member having a first jaw member at a distal end thereof, a longitudinally extending actuating means rotatable about said longitudinal axis, a second jaw member pivotably mounted to a distal end of said support means, and operating means for said second jaw member including rearwardly facing cam follower means, wherein a distal end of the actuating means is adapted to bear on said cam follower means, and is so configured that rotation of said actuating means causes pivoting of said second jaw member into and out of operative relationship with said first jaw member, and wherein the rearwardly facing cam follower means comprises two protrusions extending from substantially diametrically opposed points of the operating means and so disposed that action of a lobe at the distal end of the actuating means on one of said protrusions acts to pivot the second jaw member into operative relationship with the first jaw member, and action of a lobe on a second of said protrusions acts to pivot the jaw means away from said operative relationship.

2. A tool as claimed in claim 1 , wherein the actuating means comprises an actuating tube concentrically surrounding said support means.

3. A tool as claimed in claim 2 , wherein said distal end of the actuating means has an undulating profile with at least one lobe disposed to bear on an opposing surface of the operating means.

4. A tool as claimed in claim 3 , wherein the distal end of the actuating tube is provided with three lobes.

5. A tool as claimed in claim 4 , wherein the distal end of the actuating tube is so configured that in a first orientation of said tube one lobe is disposed to bear on a first protrusion of the operating means and the second said protrusion is disposed in a recess between other lobes of the activating tube.

6. A tool as claimed in claim 5 , wherein the protrusions are so spaced and separated by an intermediate curved zone that the second jaw member moves between open and closed dispositions by a rotational movement of the lobe of between 20 and 60 degrees.

7. A tool a claimed in claim 1 , wherein the distal end of the actuating tube is provided with a single lobe.

8. A tool as claimed in claim 7 , wherein the protrusions are so spaced and separated by an intermediate curved zone that the second jaw member moves between open and closed dispositions by a rotational movement of the lobe of between 60 and 180 degrees.

9. A tool as claimed in claim 8 , wherein the rotational movement is between 90 and 150 degrees, preferably in the region of 120 degrees.

10. A tool as claimed in claim 1 , wherein the actuating means is operatively connected to a manually operable control means.

11. A tool as claimed in claim 10 , wherein the control mechanism is so mounted pivotably to a housing that it engages in a part helical slot of a turning means integral with or operatively associated with said actuating means, whereby longitudinally directed movement of the control mechanism causes rotation of the turning means and the actuating means.

12. A tool as claimed in claim 11 , further comprising compensation means so that during said rotational movement, longitudinal movement of the actuating means occurs, whereby the lobe remains always in contact with the rearwardly facing surface of the operating means.

13. A tool as claim in claim 1 , further comprising means of generating ultrasonic vibrations and a waveguide operationally connected thereto at a proximal end.

14. A tool as claimed in claim 13 , wherein the means of generating ultrasonic vibrations is adapted to generate ultrasonic vibrations in a torsional mode.

15. A tool as claimed in claim 13 , wherein the waveguide is provided at its distal end with cutting and/or coagulating means.

16. A tool as claimed in claim 6 , wherein the curved zone is so shaped that the jaw means is caused to move comparatively slowly over a part of its travel and comparatively fast over another part of its travel.

17. A tool as claimed in claim 16 , wherein the comparatively slow part of the travel of the jaw means define a coagulation step.

18. A tool as claimed in claim 16 , wherein the comparatively fast part of the travel of the jaw means defines a cutting step.

19. The tool as claimed in claim 10 , wherein the control means comprises a trigger type mechanism.