Patent GB-1402692-A (GB)
Title: Unloading apparatus
IPC: B66F9/00
Filed: 1973-09-28
Abstract: 1402692 Platform elevators; vehicle loading platform lift W REEDER 28 Sept 1973 [4 Oct 1972] 45575/73 Headings B8H and B8E [Also in Division G3] Apparatus for use in lowering articles, e.g. rolls of newsprint or oil drums from an upper to a lower position comprises a frame consisting of a base portion 9 mounted on castors 10 and four upright posts 12 (only two of which are shown), an article receiving tray 15 being movable along the posts 12 from an upper position at which an article is rolled thereon in the direction indicated by the arrow 17 to a lower position at which the article is discharged, the tray 15 being connected by means of a pair of cables 21 (one of which is shown) which pass about pulleys 22, 25 to an anchorage 27 at the top of the frame, each of the cables 21 also passing about an idler pulley 26 mounted at the top of a piston-rod 29 which with its associated piston 30 is located inside an air cylinder 31 such that while the loaded tray 15 is descending under gravity along the posts 12 the piston-rod 29 and piston 30 move upwardly in the cylinder 31 thereby displacing air through ducts 33, 33A into a compressed air storage reservoir 34, and on discharging the load from the tray 15 the air pressure so generated in the reservoir 34 suffices to drive the piston 30 downwards so as to revert the empty tray 15 to its upper position on the frame. During movement of the tray, rollers 18, 19, 20 located at its ends engage with the posts 12 and obstruction blocks 67 which are located on the load receiving side of the frame engage with one side of the tray 15 thereby causing it to tilt about an axis adjacent to the blocks 67 to permit the discharge of the article from the tray 15 at the side thereof opposite its load receiving side, as shown in Fig. 4 (not shown). The rate of descent of the tray 15 is controlled by means of a valve 39 located between the ducts 33, 33A, said ducts being in communication with respective chambers (41, 42) in the valve, Fig. 6 (not shown), the valve further comprising a rotatable valve head (35) having a peripheral gap (36) which, upon selected rotation of the head (35) by means of a hand piece 45, varies the effective opening of a port (37) formed in a plate (38) located between the chambers (41, 42). When an article is located in the tray 15 it is engaged by a flap 73 which projects upwardly from the floor 16 of the tray, the flap 73 being pivotable into a position in which it is flush with the floor 16 to permit the discharge of an article from the tray 15 when the latter is in its lower position. A shaft (not shown) extends laterally of the tray 15 and has the flap 73 mounted thereon as well as a disc at its ends only one such disc being shown, but each disc is engaged by a trip lever 83 as shown in Fig. 1. When the tray 15 reaches its lower position an abutment 86 on each lever 83 strikes against a spur 88 formed on a lever 89 and each lever 83 is thereby disengaged from its associated disc which permits the rotation of the flap 73 under the weight of the article located in the tray 15 into its position in which it is flush with the tray floor 16. The position of the tray 15 is adjustable in order to level it relative to a vehicle deck for example, such adjustment being effected by moving on abutment block 52 on which a clevis 28 which carries the pulleys 26 rests. The block 52 is mounted at the top of a rack 53 which meshes with a pinion (56) coaxially mounted on a gear (57) which, in turn, meshes with a pinion (59) which is rotatable by a handle 66, Fig. 8 (not shown).  The apparatus described above may be incorporated in a truck or other vehicle as a permanent part thereof.