Abstract: Clamping apparatus for quickly and accurately positioning and maintaining a pair of workpieces, such as mitered end picture frame moldings or the like, in desired, generally end-to-end, angularly related positions and being characterized by evenly and resiliently applying clamping forces and positioning forces to the pair of workpieces regardless of slight variations in width of the workpieces, as follows. Backstops receive the outer longitudinal side edges of each of the workpieces and are mounted in angularly related positions corresponding to the desired positions of the workpieces.

Abstract: A device for releasably holding a movable body in a given position with respect to another body includes a pair of opposed mutually spaced end walls and a pair of opposed mutually spaced fixed walls extending between the fixed to the end walls to form therewith a frame which surrounds a given space. A control plate is situated in the latter space for movement between the end walls in a clamping direction or in a non-clamping direction, and on opposite sides of the control plate are a pair of parallel clamping plates which are parallel to the control plate while being spaced therefrom.