| 摘要 |
A form jack and hoist connector is described for use in freeing a concrete or similar masonry casting from a trough-like form in which it has been cast, whereby the form is stripped in the action of hoisting the casting for transfer of it to a point of storage or use. Castings such as those forming pre-built monolithic external cellar stairwells for attachment to subgrade foundation walls, unitized entrance landings and stairs, and the like, are typical of the kind of large heavy structures to be handled by the novel form jack. The jack consists of a central beam with projecting arms pivoted at each end. An integral eye or other means of attachment to a hoist rig is provided at the center of the beam. The free ends of the pivoted arms are adapted to be supported on portions of the form structure itself to serve as fulcrum points for leveraging the casting out of the form. Attachment means are provided intermediate the pivot point and free end of each arm to engage and lift the casting as the central beam member is hoisted, simultaneously prying the casting from the form in this lifting process.
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