Patent GB-596866-A (GB)
Title: Improvements in or relating to molding presses
IPC: B30B15/28
Filed: 1945-01-29
Abstract: 596,866. Multi-mould-cavity presses. STOKES MACHINE CO., F. J. Jan. 29, 1945, No. 2297. Convention date, Dec. 28, 1943. [Class 87 (ii)] [Also in Group XXXVII] When the two mould plates of a multi-mouldcavity press have separated, the moulded articles being carried by one of the plates, feelers traverse that plate and ride over the articles. If an article is missing, the press stops. If there are no articles missing, the operation of the press continues, the articles being then ejected from the plate. The feelers then traverse the plate again, and if all the articles have not been ejected, the press stops. Thus, the press stops (a) if all the articles do not adhere to the proper plate, (b) if all the articles are not removed from that plate, and (c) if the supply of moulding material becomes exhausted or is not properly fed. The invention is described as applied to three machines:-(1) (Figs. 1, 2, 3). The fifteen upper dies 9a, in five columns of three are carried on a stationary plate 9. The lower dies 7a are carried by a plate 7 horizontally reciprocable between a vertically-reciprocable hydraulic plunger 5 and a mould-loading device 12. The five feelers 15, one for each column of dies 9a, are carried by a horizontal bar 14 mounted on the plate 7. Each feeler comprises a plunger 15c urged upwardly by a spring 15h and carrying a roller 15g. The press, whether hydraulically or mechanically operated, is driven by an electric motor Mo which is controlled by an electro-magnetic switch A the energizing circuit of which is normally completed through a closed switch B. The switch B may be opened by clockwise rotation of a cam shaft C which is urged counter-clockwise by a spring D and clockwise by a pawl F operated by a magnet E. The shaft is held in the mid-position shown by a latch P. Operation :-From the position shown in Fig. 1, the plate 7 moves to the right, and normally each feeler 15 is depressed three times by contact with the three moulded articles 16 in each column. Depression of all the feelers thus simultaneously, to bridge five contacts 15c, 15c<1>, energises magnet M to withdraw latch P, and shaft C is turned counterclockwise by spring D. When the springs 15h raise the plunger 15e to bridge five contacts 15b, 15b<1>, the magnet E is energized and pawl F steps shaft C back to the position shown. But if an article is missing from one of the five dies in a row the corresponding plunger 15a is not depressed, its contacts 15c, 15c<1> are not bridged, the latch P is not withdrawn and on the subsequent rise of the other four plungers magnet E is energised to operate pawl F to step the shaft clockwise from the mid-position shown, thus opening switch B and stopping the motor. When in the normal operation of the press the plate 7 has moved to the right out of the press, a discharge shoot 13 attached thereto is positioned below the dies 9a, and hydraulically-operated ejectors 10 push the articles off the dies on to the shoot. The plate 7 then receives its charge of moulding material from the device 12 and starts leftward into the press. If there is one article still left on a die 9a, the corresponding plunger 15e is momentarily depressed, magnet E is de-energized and pawl F is raised by a spring (not shown). Then the plunger is raised, magnet E is energized and pawl F steps the shaft around to stop the motor. (2) (Fig. 4, not shown). The feelers 15 are mounted on a loading-board reciprocating horizontally into and out of the press. (3) (Fig. 5). The feelers 15 are fixed on a stationary part 4 of the press, and as the upper plate 9 slides leftward out of the press, the moulded articles on the dies thereof depress the plungers 15e as before. The ejecting ram 10b is separate from the ejectors 10. The moulding material may be carried into the press by a loading board, or as shown, by a horizontally-reciprocating lower plate 7. Specifications 515,790, 515,829, 564,260, and 580,542 are referred to.