| 摘要 |
A screw-type clamp for gripping structural members such as steel sheets has a generally U-shaped clamp body with projecting portions forming therebetween a material receiving slot. A screw is threadedly received through a portion of the body and has mounted thereon a material gripping element. A material gripping member is also mounted to the body portion opposing the screw, such that structural members may be securely gripped by the gripping surfaces by advancing the screw. The clamp has a freely rotatable coupling member for connection of a shackle. The coupling member includes a rotatable post protruding from the clamp body and having an axis of rotation extending through the material receiving slot, perpendicular to the screw. A lubrication passage insures free rotatability of the rotatable post during a lifting operation. The coupling member provides a rotational degree of freedom allowing, for example, a pair of clamps attached to opposite edges of a structural member to be used to effect a 360 DEG rotation of the structural member about a horizontal axis. One or both of the gripping elements may be pivotably mounted to effect a camming-in action during a lifting operation to enhance the grip of the clamp on the lifted member. In one embodiment, the gripping elements are mounted for limited universal rotation by respective ball and socket configurations. In another embodiment, one of the gripping elements is mounted for pivotal motion about a fixed pivot axis.
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