Abstract: A clamp for clamping sheets and like material has opposed elongate clamping jaws mounted for pivotal movement between a clamping condition and a relatively open, released, condition, and a latch device for effecting movement of the jaws. The latch device comprises a member of channel section within which an upper part of the jaws is mounted whereby opposite sides of the member co-operate with the two jaws, and latch levers pivotal between a stable latched position and a released position. The latch levers are linked to the jaws by a screw mechanism and co-operate with the member of channel section such that movement of the latch levers to their released position effects relative movement between the jaws and said member to enable opening of the jaws. Adjustment of the clamped and open conditions of the jaws is effected by rotation of the latch levers about the axis of the screw mechanism.