Abstract: A pneumatically driven clamping device, in particular a machine vice, has a clamping member movable in the clamping direction in a stationary housing and an adjusting arrangement for coarse adjustment of the clamping member in the clamping direction with respect to the stationary housing. Between the adjusting arrangement and the clamping member in a drive housing there is provided a power amplifier with a primary element to which pneumatic pressure can be admitted, an abutment provided at one end of the power amplifier and connected to the adjusting arrangement, and a secondary element movable in the clamping direction at the other end of the power amplifier and acting on the clamping member.

Abstract: Toggle-lever construction especially for a vise or similar holdng means. There is provided a toggle-lever construction in which one end thereof is backed against a suitable anchor device and the other end thereof bears against movable means such as the jaw of a vise. A relatively light force applied laterally of the toggle will produce a large force longitudinally thereof. In one embodiment the lateral force is applied by a longitudinally moving tapered screw. Wear on the toggle is minimized by providing rounded ends having substantially only a line contact between the components of the toggle with respect to each other and between the components of the toggle and the means engaging the respective free ends thereof.

Abstract: A clamping device having a hollow spindle screwable in a stationary vise part and a pressure rod axially slidable in the hollow spindle for exerting clamping pressure. A mechanical or hydraulic power amplifier is arranged in a cylindrical housing connected to the hollow spindle. The secondary or driven member of the power amplifier acts onto a pressure rod. The primary member of the power amplifier is acted upon by a driving element which itself is arranged in a compressed air cylinder adjoining the power amplifier housing. An additional mechanical or hydraulic power amplifier is arranged in the compressed air cylinder between the compressed air piston and the aforementioned primary member.