Abstract: An underpinning machine includes a worktable (11) having a central recess (17) housing one or a pair of underpinning heads (20,21; 120). The or each head has a magazine (18,19) of V-nails or wedges associated with it. In a single head version, the underpinning head (120) is power driven between two stop positions and is capable of operation by a drive plate (27) power operated (28,29) from spaced pneumatic rams disposed below the worktable. In another embodiment, two underpinning heads (20,21) are both selectively positionable within the area of the drive plate (27). The operation of the drive plate therefore automatically operates the underpinning heads whatever their position relative to fixed guides (31,32) of the apparatus which locate framing members (42) to be underpinned.

Abstract: A clamping head assembly for clamping frame members in an underpinning machine includes a pair of clamping members each of which has upper and lower elements spring biased apart. The lower element carries a friction pad and is connected by a pin and slot connection or a parallelogram linkage to the upper element. Downward pressure on the clamping members causes slight longitudinal movement of the friction pad tending to pinch together the frame members at a mitre joint where they are held, for example, for underpinning.

Abstract: A magazine for V-nails for use in underpinning of picture frames receives a strip of V-nails secured together by heat-bonded non-adhesive synthetic plastic material through an opening of greater width than the V-nails. A pusher has a downwardly projecting tongue which is driven in the machine and has depending side walls at its forward end affording a contact point for pushing the V-nails at their center of gravity towards a pair of locating formations and the extreme forward end. A single V-nail which may be presented either point foremost or point rearmost is removed from the end of the strip in the underpinning operation, the magazine being cut away and the pusher being cut away to permit this operation. On return of the drive member, a cam firstly returns the pusher to a stop in the magazine and then lifts the magazine from its operative position to enable it to be removed or refilled.