Abstract: A metal-stretching grip head has a row of parallel upper plates wholly to one side of a plane and having front ends and rear ends and a row of parallel lower plates wholly to an opposite side of the plane and having front ends forming at the plane with the front ends of the upper plates a mouth slot extending along the plane and open forwardly on the plane. The lower plates also have rear ends juxtaposed across the plane with the upper-plate rear ends. A one-piece C-section metal bar is snugly received in the mouth slot. Rigid structure separate from the plates and bar fixes the plates relative to one another.

Abstract: A metal-stretching grip head has a row of parallel upper plates wholly to one side of a plane and having front ends and rear ends and a row of parallel lower plates wholly to an opposite side of the plane and having front ends forming at the plane with the front ends of the upper plates a mouth slot extending along the plane and open forwardly on the plane. The lower plates also have rear ends juxtaposed across the plane with the upper-plate rear ends. A one-piece C-section metal bar is snugly received in the mouth slot. Rigid structure separate from the plates and bar fixes the plates relative to one another.

Abstract: A clamping apparatus for a metal sheet stretching machine is provided with hydraulically operated connecting rods for closing the clamping jaws onto the sheet metal. The rods transmit only compressive forces and are retracted after the tightening of the clamping jaws during stretching. Pulling cables serve to selectively open the clamping jaws.