An end effector (200) of a surgical tool comprising: a jaw assembly (250) comprising a pair of jaws (272, 274)； a wrist assembly (210) pivotably connected to the jaw assembly (250), said wrist assembly (210) including a proximal hub (212) defining a first longitudinal axis (XI-XI) and a first pivot axis (A-A) that is orientated orthogonal to the first longitudinal axis (XI-XI), and further including a distal hub (214) pivotally connected to the proximal hub (212), wherein the distal hub (214) defines a second longitudinal axis (X2-X2) and a second pivot axis (B-B) that is orientated orthogonal to the first pivot axis (A-A)； wherein the jaw assembly (250) includes a pair of spaced apart cam plates (252, 254) pivotally connected to the distal hub (214) of the wrist assembly (210) so as to be pivotable about the second pivot axis (B-B), the paid of jaws (272, 274) being pivotally connected to the support plates (252, 254) at a common pivot point (276), said jaw assembly further comprising a cam pulley (260), said cam pulley (260) pivotally connected to upright supports of the distal hub (214) of the wrist assembly (210) so as to be pivotable about the second pivot axis (B-B), said cam pulley (260) configured to rotate, and wherein said rotation causes the jaws (272, 274) to open and close.
