Patent GB-1351346-A (GB)
Title: Vacuum lifting apparatus
IPC: B66C1/02
Filed: 1971-07-12
Abstract: 1351346 Suction lifting apparatus P ECKERT 12 July 1971 [15 July 1970 11 Jan 1971 5 March 1971] 32668/71 Heading B8H Vacuum lifting apparatus comprises a lifting frame 30 on which three article-engaging suction cups are mounted, each said cup comprising a lower part 11 which sealingly engages the article, a hollow piston-rod 12 extending from the frame into each cup and having a piston 13 at its end which is connected to a sealing diaphragm 14, such that when the apparatus is lifted the rod 12 and piston 13 are moved upwardly relative to the associated cup such that a vacuum is produced between the piston 13, diaphragm 14 and the article if a vacuum-release valve mounted within the rod 12 is closed, the vacuum being released on opening of the said vacuum-release valve. Each said valve comprises a flanged valve cylinder 25 located in a bore of the piston 13, Fig. 2, which represents the closed position of the valve, the said cylinder 25 being movable upwardly relative to piston 13 thus opening the valve to permit air to pass through bores 15 in the cup and rod 12 to the region below the diaphragm 14. Opening and closing movements of each vacuum-release valve are controlled by an external automatic control system, Fig. 3, which comprises an external cylinder 31 in which is located a piston 32 connected to a pull rod 34 by which the apparatus as a whole is lifted, the cylinder 31 being connected via a conduit 24a to a control cylinder 36 which is connected via conduits 24 to a cylinder 19 located in each rod 12 whose piston 22 is connected via a rod 21 to the associated valve cylinder 25. When the apparatus is lifted the piston 32 is raised by means of the pull rod 34 and the air displaced from the cylinder 31 passes to the cylinder 36 and thence either via the conduits 24 to the cylinders 19, 42 if a valve disc in the cylinder 36 is in the position shown in Fig. 3 in which bores located below the disc 42 are closed off, to sense the raising of the pistons 22 and thus the associated valve cylinders 25 thus opening the vacuum release valves, or else to atmosphere if the valve disc 42 is in a raised position above that shown, to permit the air to escape through the said bores. Assume that an article is being carried by the apparatus, then the vacuum release valves are in their closed positions shown and the disc 42 is in its raised position. As the apparatus is set down a pawl 39 on the pull rod 34 engages a ratchet wheel 37 and rotates a disc 38 whose surfaces engage a push member 43 connected to the disc 42 causing the disc 42 to return to its lowered position in which the bores are closed off. On raising the apparatus again the air is displaced by the piston 32 from the cylinder 31 and passes to the cylinders 19 thereby opening the vacuum release valves so that the apparatus can be lifted away from the article. On lowering the apparatus again the disc 38 is rotated to cause the disc 42 to rise and thus the vacuum-release valves are allowed to close as the air passes from the cylinders 19 back to the cylinder 36 and then to atmosphere. As the disc 42 is in its raised position when the apparatus is raised again the vacuum release valves remain closed so that an article may be lifted thereby. Each vacuum release valve may be as shown in Fig. 8 (not shown) in which a diaphragm (60) is mounted between two discs (58, 59), the disc (59) being seated on the piston (13). Compressed air passing through conduit (24) causes the diaphragm (60) to bulge downwardly to abut against a stud (61) of the piston (13) thereby causing the discs (58, 59) to move upwardly thus opening the valve.