Abstract: A tool clamping mechanism (12) is provided for a tool engaging arm having a frame or chassis (18) which is moved along a path of travel toward a tool (47). The mechanism includes a tool contact member or tongue (60) and preferably includes a pair of spaced apart fingers (40) positioned to engage a groove formed in the tool (47). The tongue (60) is mounted for movement along the path of travel with the frame, such as by means of bar (62) joined to the fingers, a pin (67) supported by the bar and projecting through a slot in the tongue (60), and a rod (72) attached to the tongue which extends into the frame (18) along a bore (75). Such mounting arrangement enables the frame (18) to continue to move toward the tool (47) after the tongue (60) has contacted the tool, thereby achieving relative motion between the frame (18) and tongue (60).