Patent GB-833565-A (GB)
Title: Improvements in or relating to automatic injection machines
IPC: B29C45/03
Filed: 1957-03-04
Abstract: 833,565. Injection mouldi n g machines. SOC. DU SURBOUCHAGE ASTRA. March 4, 1957 [March 6, 1956], No. 7174/57. Class 87(2). A set of serially-disposed injection moulding machines having at least one group of four machines has an automatic controlling assembly with shiftable means for simultaneously actuati n g the machines so that from the first to the last machine of the set the machines perform the successive steps of a single complete cycle of injection, also means for automatically and successively shifting the actuating means so that each machine successively performs all the steps of a complete injection cycle, the shifting means operating at time intervals equal to the duration of the cycle divided by the number of machines in the set, so that similar periods of this cycle are phase-shifted from one machine to the next, this phase-shift having a duration equal to the above time intervals. The actuating means comprise, for the whole of the machines constituting a set disposed ringwise or for each machine in a set of aligned machines, three cams 28, 29 and 30 of which the first actuates the compressed air distributers 16 of one or more rams 1 which actuate in turn the injection pistons 2 while the other two cams have their races displaced through 180 degrees relative to that of the first cam and actuate the compressed air distributers 21 of one or more rams 12 which open and close the moulds 9, 11 and the distributers 23 controlling the compressed air mould ejection devices 22. In this arrangement, distributer 16 connects the two sides of the piston of ram 1 through pipe lines 14, 15 in turn to a feed circuit 17 and exhaust circuit 18. Similarly, the two sides of the piston of mould actuating ram 12 are connected through pipe lines 19, 20 by distributer 21 to the feed and exhaust circuits 17, 18. The ejection circuit 22 connects with the feed circuit 17 through distributer 23. Each three-cam set is driven at the rate of one revolution per injection cycle and in the case of a set of aligned machines, is angularly displaced with respect to the threecam set of the preceding, machine by an angle equal to 360 degrees divided by the number of machines in the set, the race of each cam having an angular development corresponding to the duration of one stage of the injection cycle. A simpler arrangement, Fig. 11, uses a single distributer per machine for controlling the injection rams, mould movements, and ejection means. This distributer 52 has chambers 53, 54 connected to the feed and exhaust circuits 17, 18 respectively. Three pistons 56, 57 and 58 connected by a rod 55 are slidably mounted within chamber 53 which communicates through ports 59, 60 and 61 with chamber 54. Pipe lines 22, 15 and 19 on the one hand and. pipe lines 14 and 20 on the other communicate with chamber 53 on either side of pipe line 17. During the mould opening step the distributer is in the position shown in Fig. 11. The movements of the pistons necessary to bring about the desired cycle of operation are produced by the cam 72 comprising two circular cam races 78 and 79 displaced through 180 degrees in relation to each other. These two cam races co-operate with rollers 68, 71 carried on rods 67, 70 joined by the lever 65, 69 fulcrumed at 66 and pivotally connected at one end to rod 64 pivoted on the piston rod 55. A further simplification involves the use of a single distributer associated with each set of injection maches, either aligned or disposed ringwise. This single distributer, Fig. 13, comprises a rotary disc 80 between two stationary plates 82 and 83, plate 82 having four circular series of apertures. The innermost series is connected to the pipe lines 20 of the mould actuating rams, the next series which is displaced 1/16 of a revolution (in the case of 8 machines) with respect to the first, to the pipe lines 14 of the injection rams, and the next series which is radially aligned to the first series, to the pipe lines 15 of the injection rams. The outermost series comprises on the one hand apertures radially aligned with those of the second series and connected to the pipe lines 19 of the mould-actuating rams, and on the other hand apertures disposed between every other radius of alignment of the previous four series and connected to the injection devices 22. The rotary disc 80 comprises chambers disposed in pairs alternately connected with the feed and exhaust circuits and communicating through four annular series of ports with the four circular series of apertures of the stationary plate 82.