Patent ID: 7846177

Claim:
A surgical instrument having a handle operatively connected to an elongate shaft, the handle comprising: a thumb ring member pivotably connected to a finger ring member; a first engagement member fixed in and projecting generally distally from the thumb ring member; a second engagement member pivotably mounted to and projecting generally proximally from the finger ring member, a first end portion of the second engagement member being biased into engagement with the first engagement member and defining an engaged state; and an elongate cam member pivotably connected to the finger ring member and comprising an operative contact with a second end portion of the second engagement member; wherein, the elongate cam member is at a first angle relative to the second engagement member, the operative contact is sufficient to pivot the second engagement member so as to overcome the biased engagement of the second engagement member with the first engagement member defining a released state; wherein, when the elongate cam member is at a second angle relative to the second engagement member, the operative contact is sufficient to pivot the second engagement member so as to overcome the biased engagement of the second engagement member with the first engagement member and is sufficient to bias the second engagement member out of engagement with the first engagement member defining a defeated state; and wherein the elongate cam member, first engagement member, and second engagement member are configured such that, when the handle occupies the engaged state, the elongate cam member is disposed intermediate the first angle and the second angle.