Actuation mechanism and ultrasonic surgical instrument

1. An actuation mechanism for performing an action, wherein, said actuation mechanism comprises:

a first movable trigger assembly having a first trigger;

a second movable trigger assembly have a second trigger, wherein said first trigger is movable independently with respect to said second trigger during a portion of movement of said first trigger and/or said second trigger; and

a driving member in engagement with said first trigger assembly and said second trigger assembly, respectively, wherein, said first trigger assembly and said second trigger assembly are applied different mechanical advantages;

said actuation mechanism further comprises a bias member configured for stopping said second trigger assembly until force against said driving member exceeds a predetermined limit;

wherein said force against said driving member is from said first trigger assembly;

wherein said first trigger assembly is engaged with said second trigger assembly through a sliding member.

2. The actuation mechanism according to claim 1 , wherein said mechanical advantage of said second trigger assembly is determined by position of said first trigger assembly.

3. The actuation mechanism according to claim 1 , wherein, movement of said first trigger depends on movement of said second trigger during a portion of movement thereof.

4. The actuation mechanism according to claim 1 , further comprising an off-center member, through which said driving member is actuated by said first trigger assembly.

5. The actuation mechanism according to claim 1 , wherein, said first trigger is engaged with said driving member through a first link, and said second trigger is engaged with said driving member and said first link through a second link.

6. An ultrasonic surgical instrument comprises an actuation mechanism, wherein, said actuation mechanism comprises:

a first movable trigger assembly having a first trigger;

a second movable trigger assembly have a second trigger, wherein said first trigger is movable independently with respect to said second trigger during a portion of movement of said first trigger and/or said second trigger; and

a driving member in engagement with said first trigger assembly and said second trigger assembly, respectively, wherein, said first trigger assembly and said second trigger assembly are applied different mechanical advantages;

said actuation mechanism further comprises a bias member configured for stopping said second trigger assembly until force against said driving member exceeds a predetermined limit; wherein said force against said driving member is from said first trigger assembly;

wherein said first trigger assembly is engaged with said second trigger assembly through a sliding member.

7. The ultrasonic surgical instrument according to claim 6 , wherein said mechanical advantage of said second trigger assembly is determined by position of said first trigger assembly.

8. The ultrasonic surgical instrument according to claim 7 , wherein, further comprises:

a handle portion for being held by an operator; and

a clamping assembly engaged with said driving member through an elongated shaft, which is adapted to clamp tissue.

9. The ultrasonic surgical instrument according to claim 8 , wherein, said clamping assembly is rotatable about a longitudinal axis with respect to said handle portion.

10. The ultrasonic surgical instrument according to claim 8 , wherein, said first trigger and said second trigger are arranged on opposing sides of said handle portion, respectively, at least one of which are contactable by said operator.

11. The ultrasonic surgical instrument according to claim 10 , wherein, said second trigger assembly is further adapted for providing feedback to said operator of force on said driving member.

12. The ultrasonic surgical instrument according to claim 6 , wherein, during a portion of movement of said first trigger, said second trigger rotates in direction opposite to said first trigger.

13. The ultrasonic surgical instrument according to claim 6 , wherein, during a portion of movement of said first trigger, said second trigger rotates in same direction as said first trigger.

14. An actuation mechanism for performing action, wherein, said actuation mechanism comprises:

a first movable trigger assembly having a first trigger;

a second movable trigger assembly having a second trigger, wherein, said first trigger is movable independently with respect to said second trigger during a portion of movement of said first trigger and/or said second trigger;

a driving member in engagement with said first trigger assembly and said second trigger assembly, respectively; and

a first link, through which said second trigger assembly is engaged with said driving member;

said actuation mechanism further comprises a bias member configured for stopping said second trigger assembly until force against said driving member exceeds a predetermined limit; wherein said force against said driving member is from said first trigger assembly;

wherein said first trigger assembly is engaged with said second trigger assembly through a sliding member.

15. The actuation mechanism according to claim 14 , wherein, further comprises a second link, through which said second trigger is engaged with said first link.

16. The actuation mechanism according to claim 14 , wherein, said second trigger assembly is engaged with said first link through the sliding member.

17. The actuation mechanism according to claim 15 , wherein, said second trigger is engaged with said first link through a third link.

18. The actuation mechanism according to claim 14 , wherein, further comprises an off-center member, through which said driving member is actuated by said first trigger assembly.