Medical instrument having an engagement mechanism

1 . A medical instrument comprising:

a shaft having a channel extending therethrough, said shaft including a proximal end and a distal end;

an actuating element extending through said channel, said actuating element having a proximal and a distal end;

an end effector disposed on said distal end of said shaft and operatively connected to said distal end of said actuating element, wherein said actuating element is adapted to move said end effector between a first configuration and a second configuration; and

a control moveable between a first position corresponding to said first configuration and a second position corresponding to said second configuration, wherein said control is operatively disconnected from said actuating element when said control is in said first position.

2 . The medical instrument of claim 1 wherein said shaft and said actuating element are flexible.

3 . The medical instrument of claim 1 wherein said shaft and said end effector are sized for insertion into a working channel of an endoscope.

4 . The medical instrument of claim 1 wherein said end effector is adapted to grasp tissue, clamp tissue, hold a needle, apply a fastener, apply a clip, retract tissue, cut tissue or apply an energy to tissue.

5 . The medical instrument of claim 1 further comprising an engagement mechanism including a clutching element adapted to releasably engage said control to said actuating element when said control is moved from said first position and a spring element adapted to apply a return force to said actuating element such that said end effector is biased to said first position.

6 . The medical instrument of claim 5 wherein said clutching element is formed from a rigid material having an aperture therethrough and wherein said engagement mechanism further comprises a drive element attached to said proximal end of said actuating element and inserted through said aperture, whereby moving said control from said first position orients said clutching element with respect to said drive element such that said clutching element locks onto said drive element at said aperture.

7 . The medical instrument of claim 5 wherein the clutching element includes a first gear attached to said actuating element and said control includes a second gear, wherein said first and second gears are operatively disengaged when said control is in said first position and operatively engaged when said control is between said first and second positions, and wherein said spring element is operatively positioned between said first gear and said handle such that a force of said spring element is applied to said actuating element.

8 . The medical instrument of claim 7 wherein said first gear is a rack segment that is constrained to move along a track on said handle in proximal and distal directions, and said second gear is a gear sector attached to the control and rotationally mounted to said handle such that movement of said control rotates said second gear.

9 . The medical instrument of claim 7 wherein said first gear is a circular gear rotationally mounted to said handle and said second gear is a gear sector attached to said control and rotationally mounted to said handle, and wherein said engagement mechanism further includes a drum that is concentrically attached to said circular gear, and wherein said proximal end of said actuating element is attached to said drum such that said proximal portion of said actuating element wraps around said drum when said control is moved from said first position.

10 . The medical instrument of claim 9 wherein said spring element is a watch spring attached between said handle and said second gear such that said watch spring winds as said control is moved from said first position.

11 . A medical instrument comprising:

a shaft having a channel extending therethrough, said shaft including a proximal end and a distal end;

an actuating element extending through said channel, said actuating element having a proximal and a distal end;

an end effector disposed on said distal end of said shaft and operatively connected to said distal end of said actuating element, wherein said actuating element is adapted to move said end effector between a first configuration and a second configuration;

a handle attached to said proximal end of said shaft and including a control moveable between a first position corresponding to said first configuration, and a second position corresponding to said second configuration, wherein said control is operatively disconnected from said actuating element when said control is in said first position, and an engagement mechanism for operatively connecting said control to said proximal end of said actuating element when said control is moved from said first position.

12 . The medical instrument of claim 11 wherein said engagement mechanism includes:

a clutching element adapted to releasably engage said control to said actuating element when said control is moved from said first position, wherein said clutching element is formed from a rigid material having an aperture therethrough;

a drive element attached to said proximal end of said actuating element and inserted through said aperture, whereby moving said control from said first position orients said clutching element with respect to said drive element such that said clutching element locks onto said drive element at said aperture; and

a spring element adapted to apply a return force to said actuating element such that said end effector is biased to said first position.

13 . The medical instrument of claim 11 wherein said shaft and said actuating element are flexible.

14 . The medical instrument of claim 11 wherein said shaft and said end effector are sized for insertion into a working channel of an endoscope.

15 . The medical instrument of claim 11 wherein said end effector is adapted to grasp tissue, clamp tissue, hold a needle, apply a fastener, apply a clip, retract tissue, cut tissue or apply an energy to tissue.

16 . The medical instrument of claim 11 wherein said engagement mechanism includes:

a clutching element adapted to releasably engage said control to said actuating element when said control is moved from said first position, wherein said clutching element includes a first gear attached to said actuating element, and said control includes a second gear, wherein said first and second gears are operatively disengaged when said control is in said first position and operatively engaged when said control is between said first and second positions; and

a spring element adapted to apply a return force to said actuating element such that said end effector is biased to said first position, wherein said spring element is operatively positioned between said first gear and said handle such that said force of said spring element is applied to said actuating element;

17 . The instrument of claim 16 wherein said first gear is a rack segment that is constrained to move along a track on said handle in proximal and distal directions, and said second gear is a gear sector attached to said control and rotationally mounted to said handle such that movement of said control rotates said second gear.

18 . The instrument of claim 16 wherein said first gear is a circular gear rotationally mounted to said handle and said second gear is a gear sector attached to said control and rotationally mounted to said handle, and wherein said engagement mechanism further includes a drum that is concentrically attached to said circular gear, and wherein said proximal end of said actuating element is attached to said drum such that said proximal portion of said actuating element wraps around said drum when said control is moved from said first position.

19 . The medical instrument of claim 16 wherein said shaft and said end effector are sized for insertion into a working channel of an endoscope.

20 . The medical instrument of claim 16 wherein said end effector is adapted to grasp tissue, clamp tissue, hold a needle, apply a fastener, apply a clip, retract tissue, cut tissue or apply an energy to tissue.