and a forward projection 116 on the release button 30 as the yoke 86 moves distally in response to proximal movement of the closure trigger 26 an upper latch arm 118 of the release button 30 moves along an upper surface 120 on the yoke 86 until dropping into an upwardly presented recess 122 in a proximal lower portion of the yoke 86 the release spring 112 urges the release button 30 outward which pivots the upper latch arm 118 downwardly into engagement with the upwardly presented recess 122 thereby locking the closure trigger 26 in a tissue clamping position the latch arm 118 can be moved out of the recess 122 to release the anvil 18 by pushing the release button 30 inward specifically the upper latch arm 118 pivots upward about pin 123 of the second base section 52 the yoke 86 is then permitted to move proximally in response to return movement of the closure trigger 26 a firing trigger return spring 124 is located within the handle portion 20 with one end attached to pin 106 of the second base section 52 and the other end attached to a pin 126 on the firing trigger 28 the firing return spring 124.