Hoist for sheet material - has locking lever or shoe which wedges against collar when cam coupled to hook rotates in unlocking direction

摘要

The sheet hoist has a body with a pivotally mounted locking cam coupled by a rod, chain or cable to a hook assembly. A lever or shoe is pivoted on the body and is resiliently pressed against a collar which is coaxial with the cam pivot and rotatably coupled to the cam. The lever or shoe wedges against the collar when the cam tends to pivot in the unlocking direction. The tangent of the collar at its point of contact of the lever or wedge pref. forms an angle between 65 deg. and 88 deg. with the line between the lever and collar axis.