Patent GB-1396693-A (GB)
Title: Grab for handling loads
IPC: B66C1/30
Filed: 1971-04-13
Abstract: 1396693 Lifting grabs C E J BLACKSTONE and G H WILLIAMS 10 July 1972 [13 April 1971] 9274/71 Heading B8H A grab for handling loads comprises a central member 1 having connected to each side thereof a set of load supporting forks 10 mounted on beams 7, the forks 10 being movable towards and away from each other for engaging underneath a load to support it and for releasing the load, the grab including a load restraint member 20 associated with each set of forks 10, each member 20 consisting of a number of fingers 30 (only one shown for each member 20), which are movable with the forks 10 inwardly into a load engaging position, the fingers 30 remaining in engagement with the load after the forks 10 have been retracted therefrom, the members 20 thereby preventing the load from shifting or skewing and also maintaining it centrally aligned with respect to the forks 10. Each beam 7 has a vertical member 5 extending therefrom, to which is pivotally connected at 14 one end of a cross link 3 whose other end is connected to a roller 15 for movement along a central vertical member 4, the other cross link 2 being pivotally connected at 13 to the member 4 and having a roller 16 at its other end for movement in a guide-way 26 attached to the member 5. Each pair of cross links 2, 3 is connected by means of braces 6 to a similar pair of cross links (not shown), on the other side of the grab. Movement of the sets of forks 10 towards and away from each other is effected by means of a winch 12 whose cable 24 passes about a pulley 23 mounted on a horizontal cross beam (21) extending between the rollers 15, Fig. 2 (not shown). When the winch 12 raises its cable 24 the pulley 23 and thus the pulleys 15 are raised, and by means of the sets of cross links 2, 3 the members 5 and beams 7 are moved outwardly. On lowering the winch cable the weight of the cross links and cross beam (21) causes the said cross beam to move downwardly and the beams 7 (and forks 10), thus move inwardly towards the load to be engaged. The members 20 previously referred to on each side of the central member 4 are respectively mounted on a horizontal actuating rod 35 which at one of its ends engages by means of a recess 70 therein with a roller 38 on the associated member 5 and thus moves with the member 5 and beam 7 assembly, the other end of each rod 35 passing through rollers 39 on the member 4. As each rod 35 moves inwardly with its beam 7 the notches 47 of a ratchet plate 45 connected thereto pass beneath a pawl 50. As the fingers 30 move inwardly with the associated forks 10 they engage with the side of a load 11 and stop moving and on continued inward movement of the forks 10 the actuating rods 35 are caused to lift such that each recess 70 disengages from its roller 38, each rod 35 passing between the rollers 38 until the forks 10 engage the load 11. The pawl 50 has already engaged in a notch 47 of the ratchet plate 45. The grab is then transported to the unloading location by lifting means connected by cables 19A to a frame 1 attached to the grab. To release the load 11 the winch 12 is operated to raise the cross beam (21) thus causing outward movement of the beams 7 and forks 10 away from the load 11, the fingers 30 remaining in engagement with the load 11 due to the fact that the pawl 50 is in engagement with the ratchet plate 45. On further outward movement of the beams 7 and forks 10 a bracket 42 engages a nut 60 on the end of a rod 61 which is connected to a bar 55 running alongside the ratchet plate 45. Outward movement of each rod 61 causes the associated bar 55, by means of slots 56 therein, to move upwardly to disengage the associated pawl 50 from the notch 47 thus freeing the actuating rod 35 and thus the members 20, 30 for outward movement along with the side beams 7, the recess 70 in each rod 35 having engaged with its roller 38. Instead of the winch 12 hydraulic or pneumatic rams may be used to actuate the cross links.