Patent GB-763957-A (GB)
Title: Vacuum filling machine
Inventor: MCCARTHY EDWARD JOSEPH
IPC: B65B57/02
Filed: 1954-07-23
Abstract: 763,957. Filling-machines. PNEUMATIC SCALE CORPORATION, Ltd. July 23, 1954, No. 21615/54. Class 94(1). A machine for filling cartons with granular material by vacuum comprises a series of filling heads 20 and vertically-movable platforms 10 carried by a continuously-rotating spider 76, the cartons 12 being transferred in succession from a belt conveyer 18 to the platforms by a reciprocating pusher 26 and each platform being elevated as it moves to position 25 to engage a carton with the associated head 20. After the filling operation, each platform is lowered and the filled carton is engaged by one of the arms 221 of a rotary spider 22 and transferred along guide rails (not shown) to a discharge conveyer 24. Each platform is secured to the top of a cylinder 66, Fig. 17, which is slidable on a rod 68 having a central bore 67 to which pressure air is supplied under the control of a rotary valve 96 through pipes 110, 114 and a valve 112. The valve 96 comprises a stationary lower ring formed with an arcuate chamber 98 to which pressure air is supplied through a pipe 104 and a rotary upper ring 100 formed with ports 102 communicating with the pipes 110, whereby the platforms are elevated in succession as the spider rotates. The lower ring is also formed with a port 312, Fig. 16, which is connected to the pipe 104 through a pipe 314 fitted with a check valve 316 and relief valve 318, a port 320 connected to a relief valve 324 and an atmospheric port 326, whereby the air pressure in each cylinder 66 is progressively lowered after the completion of the filling operation to allow the associated platform to descend. The elevation and lowering of the platforms is further controlled by a stationary cam 120 engaging rollers 122 thereon, and each platform is prevented from rotating about the axis of the rod 68 by a roller 124 engaging vertical guides 126. Each valve 112 is provided with an operating arm and is normally maintained open. The normal operation of the pusher 26 withdraws an abutment from the path of the operating arms of the valves 112, but if a carton is absent from the line on the conveyer 18 the operation of the pusher is prevented by a spring- loaded latch 131, the abutment is not withdrawn and the arm of the valve associated with the platform at the loading position is moved to close the valve so that the platform is not elevated. The valve is reset automatically at the end of the cycle of operation. Each filling head, Fig. 26, is formed with suction ports 186, 188 and a material inlet port 184 and is secured to the underside of a plate 190 forming the bottom of an annular hopper. A shroud 204, formed with a suction port 220, is slidable on rods 206 and comprises a rubber skirt 217, which is engaged by the associated platform 10, and sections 210, 212 interconnected by a rubber band 214 which is urged into sealing engagement with the carton flaps by blades 216 mounted on springs 218. The suction ports of each head are connected via a manifold 224, Fig. 1, and pipes 228 and 236, Figs. 8 and 17, to chambers 230 and 238 in a valve 180, the chamber 238 being open to atmosphere and the chamber 230 communicating through a port 252 controlled by a valve 260 with a third chamber 250 which is connected by a pipe 254 to a source of vacuum. The ports to which the pipes 228 and 236 are connected are controlled by valves 274 and 284 which are operated by stationary cams 278 and 288. As a platform 10 is elevated to engage a carton with one of the heads 20, an abutment 272 on the cylinder 66 engages a lever 268 to open the valve 260, whereby the carton is alternatively evacuated and vented to atmosphere until it is filled with the granular material. If a carton becomes jammed in a filling head during the elevating operation so that the platform is not fully elevated, the latter engages a feeler mechanism 13 at position 25 which operates to open a switch in the circuit of the electric motor driving the machine. A second feeler mechanism 15 is arranged adjacent the discharge station to detect the absence of a filled carton from a platform as it is lowered from a filling head and to open another switch in the motor circuit if this occurs. This switch is shunted by a third switch arranged to be closed by the underside of a platform which has not been elevated due to the absence of an empty container at the loading station. Specification 763,958 is referred to.