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US 4,792,172 AGranted
Gripping and lifting clamp for pipes and cylindrical objects of large dimensions
AssigneeRiva Calzoni S.p.A.
InventorsPaolo Montanari, Oneglio Sala
Life of this patent
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AssigneeRiva Calzoni S.p.A.
InventorsPaolo Montanari, Oneglio Sala
Estimating the term…
A gripping and lifting clamp for pipes and cylindrical objects has an annular body equipped to be suspended and lifted. Inside the annular body is a plurality of jaws slidable on guides integral with the annular body and inclined converging towards the center downwardly. The jaws are connected by connecting rods to an axially movable common ring, carried by controllable actuating members adapted to bring the ring from a raised position to a lowered position, thereby determining, via the connecting rods, sliding of the jaws in the axial direction of the annular body on the inclined guides, between a raised, widened position and a lowered, closed position, in which the jaws come into contact with and grip onto the external surface of the pipe or cylindrical object to be lifted. The angle of inclination of the guides is such as to determine, due to the friction existing between jaws and pipe, the checking and support of the pipe itself by sticking friction.
A gripping and lifting clamp for a cylindrical object, comprising:
Dependencies are inferred from the claim text.
Elevators, i.e. rod- or tube-gripping devices: slip-type elevators
And applying frictional forces: to vertical edge portions of sheets, tubes, or like thin or thin-walled articles
Earth or rock drilling
Cranes
Term ended 30 Mar 2007 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to a gripping and lifting clamp for pipes and cylindrical objects with vertical axes, and is intended to permit a reliable support of the pipes or cylindrical objects by applying a limited clamping force even for pipes or objects of considerable weight.
In numerous circumstances it is necessary to grip and raise pipes and cylindrical objects with their axes being vertically oriented, the objects being of great weight, for transporting them and locating them at the desired site.
An example of such an operation is the construction of extraction wells, in which a number of drill pipes are to be positioned in succession, or the positioning of foundation on piles and the like, as in the case of marine platforms for petroleum extraction.
The above and other objects, features and advantages of our invention will become more readily apparent from the following description, reference being made to the accompanying highly diagrammatic drawing in which:
FIG. 1 is an axial section through a lifting clamp according to this invention taken along the line I--I of FIG. 2;
FIG. 2 is a section taken along the line II--II of FIG. 1;
As shown in FIGS. 1 to 3, the clamp for lifting pipes according to this invention comprises an annular body 1, equipped with lower and upper flanges 2, 3 and with reinforcing rings 4. Within the annular body there are disposed a plurality of radial centering plates 5 and a plurality of inclined guides 6, carrying the clamping jaws 7.
The body 1 carries, externally, the suspension means in the form of lifting lugs 8, by which the clamp is connected to the lifting and placing members for the pipe to be gripped by it.
The jaws 7 are connected, by means of the connecting rods 9, to a common ring 10, movable in the axial direction. To this ring there are connected, by their movable rods, a plurality of cylinders 11, secured at the opposite end to the base flange 2 of the body 1.