GB677469A - Improvements in and relating to pneumatically operated timing devices - Google Patents

Abstract

677,469. Moulding machines. BRITISH MOULDING MACHINE CO., Ltd. Feb. 6, 1951 [Feb. 6, 1950], No. 3005/50. Class 83 (i). [Also in Group XXIX] A pneumatically-operated timing device, e.g. for controlling the time a mould is jolted, has a valve and a diaphragm arranged so that a steady air pressure can be applied to the valve to keep it shut while a progressively increasing air pressure is applied to the diaphragm and tends to open the valve, the rate of this increase being adjustable to vary the time before the valve is opened. The valve 28 may be held on its seat 30 and in contact with the diaphragm 24 by a spring 26. The steady pressure is applied above the valve 28 via passages 14, 36, 34 and the increasing pressure, via an adjustable needle ball or valve 20, passage 18 and reservoir 12, below the diaphragm. When the pressure supply to 14 is released this releases the pressure on the left side of a valve 48 and the pressure in the reservoir 12 opens the valve 48 and is thus discharged to reset the timer. As applied to a moulding machine J, air to cause jarring is supplied from a main 86 by a valve 64 which is opened by a shuttle 84 moved to the right by air admitted by a hand-operated valve 93 and pipes 95, 92. Air is at the same time supplied by a pipe 100 to the timer T. When the valve 28 opens the air passes, via a pipe 98, to move the shuttle 84 to the left, thus closing the valve 64 and opening a valve 66 to stop the jolting process and exhaust the pipe 100 to reset the timer. This action can be effected before the timer operates, by opening a valve 931.