Clamping device for lifting slab, panel or sheet material

Clamping device suitable for lifting and handling of sheet-like objects, having a rigid frame with a fixed jaw that provides a first clamping surface, a movable jaw that provides a second clamping surface that is substantially parallel to the first clamping surface, the movable jaw being supported at the frame for reciprocating, linear movement towards and away from the fixed jaw, and an operating mechanism arranged to bias the movable jaw towards the fixed jaw in response to an actuating force being exerted on a tensile force transmitting member of the operating mechanism, to thereby abut the respective clamping surfaces onto opposite faces of the sheet-like object received between the jaws and frictionally clamping same against displacement, characterised in that the movable jaw comprises a sliding plate on which the second clamping surface is provided, the sliding plate being inclined at an angle of about 8 to 12 degrees with respect to the first and second clamping surfaces and being supported at the frame to maintain said angle during movement to and from the fixed jaw, in that during movement to and from the fixed jaw the sliding plate translates without rotation relative to the fixed jaw, and in that the tensile force transmitting member is guided and supported at an upper location of the sliding plate that substantially aligns with or overhangs the second clamping surface, wherein the operating mechanism includes a drive pulley that is mounted on the sliding plate of the movable jaw with its axis of rotation perpendicular to the plane of the sliding plate, at least four bearing rollers are arranged to support the pulley in parallel relationship at the facing sliding plate surface, at least two actuating cams are provided on the pulley so as to protrude from the pulley surface that faces away from the sliding plate, the at least two actuating cams being disposed symmetrically and concentrically about the rotation axis of the pulley and extending along an arc sector radially inwards of the pulley circumference, the cams having a height that increases from near the pulley face to a maximum height that is related to the maximum spacing between the fixed and movable jaws of the clamping device in their fully spaced apart position, the cams each defining a sloped guide and bearing surface for respective actuator rollers that are secured in fixed relationship on a stationary part of the clamp frame that faces the pulley, the arrangement being such that upon rotation of the pulley, the actuator rollers travel along the guide and bearing surfaces of the cams thereby displacing the pulley and therewith the associated sliding plate along the axis of rotation of the pulley relative to the rigid frame.

A device for lifting and handling sheet, panel and slab materials using a fixed jaw and a movable jaw for gripping the material to be lifted, comprising:

• a rigid frame having a first and a second side arranged in spaced apart and opposed relation to each other, with each side having an upper portion and a lower portion, at least two upper horizontal cross-bars and at least two lower cross-bars connecting the first and second sides to form the rigid frame, the lower portion of the first side extends downwardly and having an inner surface and an outer surface, the inner surface being vertical and substantially flat, the lower portion of the first side forming the fixed jaw, the lower portion of the second side extends downwardly and at an angle relative to vertical, a movable plate mounted on the at least two lower cross-bars for moving thereon toward and away from the fixed jaw, the movable plate is mounted having a lower portion which extends at an angle relative to vertical which is equal to the angle of the lower portion of the second side, a cam pulley mechanism for driving the movable plate along the at least two lower cross-bars, the cam pulley mechanism comprising a pulley mounted on the movable plate for rotation, two cam members mounted on one side of the pulley for rotating therewith, and a cable wound around a groove provided on the outer circumference of the pulley for rotating the pulley, the cam members each having a cam surface facing away from the one side of the pulley and engaging a respective roller of at least one pair of the diametrically opposed rollers such that, when the cable is pulled upwardly, the cable rotates the pulley as the cable unwinds from the pulley, the cam surfaces rotate and ride on the at least one pair of diametrically opposed rollers to drive the movable plate and the movable jaw toward the fixed jaw while the angle of the movable plate is maintained the same.