The invention relates to a toggle lever clamping device, specifically, for use in vehicle body manufacturing in the automobile industry, wherein the rod acting as a piston rod is provided at its end section facing a toggle joint system with a thread by which the rod may be screwed a greater or lesser distance within a sleeve-like component of a linkage element, specifically, a fork head, in order to change the opening angle of a clamping arm. Adjustment of the opening angle may be effected without disassembling the toggle lever clamping device, specifically, for example, by inserting a tool, especially a screwdriver, through a hole in the base cover so as to rotate the piston rod left or right about its longitudinal axis in order to adjust the opening angle. Undesirable rotation is prevented by using a guide plate. A ball screw may also be employed in place of the thread.