US1962700A - Grab - Google Patents

Description

June l2, 1934.

P. J,-M. T. ALLARD 1,962,700

GRAB

Filed Sept. l. 1951 5 Sheets-Sheet l Egj Invtn'or Pkrre dean MareTheodoreRUarrL :B lf I June 12 1934' P. J.M. T. ALLARD GRAB Filed Se j Ill/Imi!) 3 Sheets-Sheet 2 pt. l. 1931 Pfarre dean MaricThQocm-e/Ulard,

GRAB

Filed Sept. l, 1931 3 Sheets-Sheet 3 InuenTr. Pile rre Jean MariCeodor/lllard Patented June 12, 1934 UNITED STATES PATENT OFFICE France,

assignor to Societe Francaise De Construction De Bennes Automatiques, Le Havre,

France Application September 1, 1931, Serial No. 560,650 In France October 9, 1930 3 Claims.

The present invention relates to improvements in grabs for handling blocks and has for its main object to provide means whereby a block or blocks, whose periphery is or are irregularly shaped, may be grasped.

Said grab is chiefly remarkable in that it comprises jaws, which are partly or Wholly independent of one another, and are each provided with a distinct clasping mechanism such that said jaws may be closed unequally, which makes it possible to apply them upon the periphery of the blocks, while distributing the efforts in a substantially even manner.

Preferred embodiments of my invention will be hereinafter described with reference to the accompanying drawings, given merely by Way of example and in which:

Fig. 1 is an elevational view, in the closed position, of a grab according to my invention;

Fig. 2 is a side view of the same grab in the closed position;

Fig. 3 is an elevational view of the grab clasping a block of any shape whatever;

Fig. 4 is a horizontal section on the line 4-4 of Fig. 3.

According to the embodiments shown, the grab consists of a strong frame 1, carrying two parallel shafts 2, on each of which is pivoted a set of independent jaws 4, the jaws of a set being preferably arranged opposite the. jaws of the other set. The number of said jaws will vary according to the nature of the objects to be handled. Each jaw is provided with a sleeve 6 through which passes the corresponding shaft 2 about which the jaw may pivot freely. One of the extremities 7 of the jaw serves to pick the block, while the other extremity 8 forms a bracket, on which are mounted one or two tackle pulleys 9.

In order to insure a certain symmetry in the displacement of the two jaws which are located opposite each other, two pivoting connecting rods 10 and 11 (Fig. 1) are mounted on each jaw in such a manner that the points 12 and 13, at which they are fixed to the jaws respectively, describe circular arcs corresponding to the same angle. However, in order to allow the jaws a certain freedom and to give them a certain independence, rods 10 and 11 are connected through two coil springs 14 and 15.

The closing mechanism may consist of chains, cables or any other means. They comprise, for instance, several hoisting cables or chains (Figs. 1 and 2), or a single hoisting cable 16 (Fig. 3). Said cable or cables penetrate into the grab and or chains 16, pulleys 9 and 18 move towards each other, thus causing jaws 4 to pivot about shafts 2. 'Ihe grab is thus closed. As disclosed in Figs. 3 and 4 it is evident that should the grab grasp a body having an irregular outer shape the different jaws though being applied against the body will not all move in the same manner, and will not occupy symmetrical positions. When a jaw has to perform a greater work than the other one which is located opposite it, springs 14 and 15 are compressed or expanded, thus permitting the efforts to be distributed among said jaws in a substantially even manner.

One of the great advantages of my invention lies in the fact that it is not possible to have one single jaw furnish the whole of the grasping effort, as takes place with ordinary grabs, which get out of shape when they carry a large block or get caught in an obstacle. In such grabs the part that is thus caught has to support the whole effort of the hoisting apparatus multiplied by the number of pulleys of the tackle.

In the grab according to my invention the effort of each jaw can only be equal to the hoisting force merely multiplied by the number of pulleys provided for said jaw and insuring the independent closing of the same.

The above described arrangement also allows the jaws to surround the blocks when they are sufficiently small and thus to avoid dropping them when they are being hoisted or transported.

While I have disclosed what I deem to be a preferred embodiment of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of my invention as comprehended within the scope of the appended claims.

What I claim is:

1. A grab, comprising at least one pair of opposite pivoting jaws, means for closing said jaws, and a yielding connection between two opposite jaws, said yielding connection comprising two connecting rods, these rods being pivoted at one end on the respective jaws, and at least one spring connecting together both other ends of the rods.

2. In a grab, a frame, a plurality of pulleys mounted on said frame, a plurality of pairs of jaws, each of said jaws being independently mounted and pivotally supported onsaid frame, pulleys mounted on one end of each of said jaws, and a single drawing member successively passing over said rst and last mentioned pulleys, in order to close and open the jaws, to support the load, whereby the two jaws of each pair of jaws may receive dierent angular displacements.

3. In a grab, a frame, a plurality of pulleys mounted on said frame, a plurality of pairs of PIERRE JEAN-MARIE THEODORE ALLARD.

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