GB863078A - Improvements in moulding machines - Google Patents

Abstract

863,078. Moulding-machines. PNEULEC Ltd. Dec. 23, 1959 [Sept. 23, 1958], No. 30304/58. Class 83 (1). A moulding-machine of the kind in which a mould-carrying table 14 is vertically movable relative to the body of the machine by compressed air admitted below the table, and an impact is applied to the table by a vertically movable jolt piston 10 while the table is in a state of suspension, is characterized in that the jolt piston works in a cylinder 11 in which it is supported by air under pressure, the admission of compressed air between the upper end of the piston 10 and the table lifting the table and depressing the piston against the resistance of the air in the lower end of the cylinder 11 below the piston. Air is admitted to the space 27 between the table and the piston 10 through a normally closed valve 28, which is opened by engagement of the table and the piston 10, the piston being raised into this position by air whose pressure is adjusted according to the weight on the table. Admission of pressure air through the valve 28 moves the table upwardly and the piston downwardly until it clears the sleeve 35, whereupon the pressure air flows to exhaust through ports 36, the table falls and the piston moves upwardly to give a jolting impact, the valve 28 is reopened by the jolt piston, and the cycle is repeated. The squeeze piston 12 is moved upwardly by pressure air admitted at 25 carrying the table with it after engaging the depending sleeve 13. The space beneath the jolt piston is therefore reduced, and the pressure in it is increased, and is compensated by increasing the pressure above the jolt piston to continue jolting during squeezing. There may therefore be two separate air feeds to the space 27 between the jolt piston and the table, one feed being through a restricted orifice and used during jolting only, the other being unrestricted and used during the squeeze.