Handling: hand and hoist-line implements – Grapple – Socket and slip wedge
Patent
1997-09-19
1999-04-13
Cherry, Johnny D.
Handling: hand and hoist-line implements
Grapple
Socket and slip wedge
2941031, 2941191, B66C 148
Patent
active
058935959
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to devices suited to the lifting and handling of slab, panel or sheet materials by gripping their faces at one edge. It is particularly concerned with devices suitable for lifting and handling heavy slabs or sheets of masonry, concrete, marble, granite, metal and the like materials. However, the use of the device is not limited to the such applications as it can be usefully employed horizontally as a clamp or haulage attachment.
As heavy slab, panel or sheet materials are commonly stored standing up and are gripped by lifting devices at their upper edges, it will be convenient to describe the lifting or handling device of this invention as if it were oriented to grip the faces of a standing slab across its upper edge. Thus, although parts of the device will be referred to as being `vertical` or `horizontal`, it will be appreciated that this terminology is adopted for clarity and convenience only as the device can be used at any angle from horizontal to vertical.
BACKGROUND TO THE INVENTION
Heavy slabs and sheets of material are commonly stacked standing on an edge leaning against an A-frame. To lift the outer slab from the stack, it first must be pivoted away from the adjacent slab until it can be gripped by a lifting device. The angle through which the outer slab must be pivoted depends upon the clearance needed to allow the lifting device to engage the slab. Since the lifting devices almost universally employed are of the scissors (or lazy tongs) variety, the outer slab must be pivoted through a substantial angle. This can be very dangerous for the operator as the heavy outer slab is likely to over-balance and fall. Also, valuable slabs of materials such as marble and granite are likely to break when they fall resulting in considerable financial loss.
Furthermore, it is often necessary to position a slab or panel which has been lifted by a device against a wall or vertical frame to which it is to be secured. Again, the use of scissors-type lifting devices often means that the slab or panel must be propped well off-vertical in a potentially dangerous position while the device is disengaged. Only after the device has been removed is it possible to then tilt the slab or panel to the vertical position in which it is to be fixed. The vertical clearance above the slab or panel for the attachment and/or removal of the scissors-type device also presents substantial problems in practice.
OBJECTIVES OF THE INVENTION
It is the general object of this invention to provide an improved lifting device suitable for use in lifting heavy slabs or sheet material from a standing stack. The invention also seeks to provide a device which will have application as a clamp or a haulage attachment for use with sheet and other workpieces.
OUTLINE OF INVENTION
The present invention is based upon the realization that a simple and compact lifting device for lifting and handling heavy slab and sheet materials would result if the lifting force were to be applied through a tension member to a carriage that travels in a tapered housing or frame to drive a moving jaw or plate toward one side of the frame--which then forms a fixed jaw. Conveniently, the housing or frame has two substantially vertical sides which have their upper portions rigidly joined by a substantially horizontal cross-member on which the moving jaw (which is arranged substantially vertical) is slidably mounted. The lower portion of the side opposed to that which forms the fixed jaw conveniently diverges downwardly and away from the fixed jaw so that the carriage can be accommodated between it and the moving jaw. As the side which forms the fixed jaw need be no thicker than its strength requires, it permits the device to be attached to and detached from a slab with only enough clearance to enter the fixed jaw between that slab and an adjacent slab or wall frame. Such a device also requires little headroom for its attachment and detachment from the slab or panel.
The carriage is preferably provided with low-friction bearings
REFERENCES:
patent: 2387408 (1945-10-01), Pertuit
patent: 2550424 (1951-04-01), Penn
patent: 2559223 (1951-07-01), Murray
patent: 2569966 (1951-10-01), Arrigoni
patent: 3008749 (1961-11-01), Gowan
patent: 3101956 (1963-08-01), Muller
patent: 3197250 (1965-07-01), Trotta et al.
patent: 3244291 (1966-04-01), Dexter
patent: 3292964 (1966-12-01), Albert
patent: 3524670 (1970-08-01), Ilich
patent: 3851358 (1974-12-01), Janosko
patent: 3926468 (1975-12-01), Kondo
Cherry Johnny D.
Herdgraph Pty Ltd
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