Handling: hand and hoist-line implements – Grapple – Lewises
Patent
1995-04-07
1997-04-29
Kramer, Dean
Handling: hand and hoist-line implements
Grapple
Lewises
294 11, 521252, B66C 166
Patent
active
056241470
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a lifting ring designed for lifting, transporting, or turning over heavy loads, such as prefabricated building elements, in particular after said elements have been molded, where said elements are particularly, but not exclusively, thin panels.
BACKGROUND OF THE INVENTION
Such rings are known and used on a wide scale. Their purpose is to enable a mechanical link to be established between an anchoring device incorporated in the concrete and a hook of a hoist such as crane.
More particularly, the present invention relates to a ring designed to co-operate with an anchoring device having an eye or a tear-out cone associated with a cylindrical head, even though the ring may also be implemented with other anchoring pieces.
When the concrete is being cast, the anchoring piece projects into a void that is hemispherical or partially hemispherical so as to be accessible after unmolding or removal of shuttering.
Such a ring is described in FR-A-1 568 605 and in FR-A-2 302 398 (HAEUSSLER). It comprises a coupling piece or yoke for coupling with the head of the anchoring device and a ring proper or shackle which provides the connection between the coupling piece and the hook of the hoist.
The yoke includes a groove or slot in the form of a circular sector in which the head of the anchoring device is received. In certain known lifting rings, the spherical coupling piece is hinged to the shackle in such a manner as to be capable of pivoting between a position in which the head can be engaged and disengaged in the groove, and a transport or handling position in which the head of the anchoring device is in abutment against the bottom of the groove.
The prefabricated element can thus be transported in complete safety so long as the rated load of the anchor piece corresponds to the weight of the element. After transport, the groove can be moved relative to the head of the anchoring device until the disengagement position is reached.
The top portion of the yoke includes a hinge eye or hole extending orthogonally to the plane of the groove and located eccentrically relative to the center of the hemispherical portion. The hook-receiving shackle is itself engaged in the hole by a circular section arc or rod that enables the parts to be hinged relative to each other. In order to facilitate relative rotation between the yoke and the head of the anchoring device, it is also known to provide said part with a handling tab or arm. The tab may be remotely controlled by means of a cable.
It is necessary to prevent the shackle or coupling part spoiling the surface of the concrete which is still somewhat fresh. That is to avoid subsequent expensive finishing on-site.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention is to propose a lifting ring making it possible to work in complete safety, even with thin panels, while limiting the movement of the yoke relative to the shackle. To this end, the body of the yoke is hemispherical and laterally truncated so as to be capable of working with heads of anchoring devices included in narrow spaces as is made necessary by the thinness of certain prefabricated panels.
Proposals have already been made in FR-A-2 479 166 to limit such movement by acting while the yoke is in the locked position on the head of the anchoring device to bring the above-mentioned handling arm into abutment against the transverse portion that is used for this purpose in the ring of the shackle.
In the past, since the shape of the yoke has been substantially hemispherical or substantially a truncated hemisphere, the manufacturer has ensured that the hinge hole of the shackle runs into connection radii that leave a large amount of movement available, over more than 180.degree., with abutment being formed as mentioned above.
The idea on which the invention is based consists in using the coupling walls of the hinge hole as abutments for limiting relative motion between the yoke and the shackle.
According to the invention, the lifting ring for prefabricated building eleme
REFERENCES:
patent: 3371951 (1968-03-01), Bryant
patent: 4173367 (1979-11-01), Haeussler
patent: 4398762 (1983-08-01), Haeussler et al.
patent: 4634164 (1987-01-01), Fricker
patent: 4671554 (1987-06-01), Lancelot
Arteon Marcel
Joannet Lucien
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