Patent GB-735362-A (GB)
Title: Improvements in machines for moulding stiffener blanks
Inventor: FORSTER HENRY ATKINSON RONALD
IPC: B29C31/08
Filed: 1953-03-23
Abstract: 735,362. Moulding shoe stiffener blanks. PEMBERTON & CO., Ltd., A. March 17, 1954 [March 23, 1953], No. 7917/53. Class 87 (2). A machine for moulding shoe stiffener blanks and comprising a male mould part mounted on a carrier, a pair of jaws co-operating with the male mould part and a "wiper" plate vertically movable to turn down an edge of a blank. of material projecting from the mould includes, in combination, means for ejecting the male mould part or "leg" 1 from between the 'mould jaws 3 after each moulding operation, a fluid pressureoperated main ram 6 for raising and lowering the leg carrier, fluid pressure-operated means for feeding stiffener blanks into the mould, and fluid pressure-operated means for ejecting the leg from the mould soon after the leg has commenced to move down, the various fluid pressure-operated means being electrically controlled and adapted to function automatically in suitable timed relation. The jaws 3 are caused to rock inwards, to press the stiffener blank on to the leg, or outwards in a mouldopening movement, by the movement of the leg carrier 2, transmitted through springs 31. Alternatively the rocking of the jaws may be fluid operated. The leg carrier 2 is raised and lowered by a hydraulically operated ram or piston 6 in a cylinder HC, oil pressure for the purpose being supplied by a pump U1 driven by a motor M2. The wiper plate 4 is operated by a piston 8 in a compressed air cylinder 7, supplied through a valve V5 from a header 9. The mechanism for feeding blanks to the mould broadly comprises a feed head 15, moved towards and away from the mould by a pneumatically operated piston 23 in a cylinder 22, with a hopper 16 in which the blanks are stacked, and a blank feeder 18, pneumatically operated by a piston and cylinder 21, 20 to feed blanks along a blank supporting rail 17 into the mould, both cylinders 20, 22 deriving air from the header 9 through a valve V4. Fig. 2 shows the electrically controlled hydraulic and pneumatic circuits, of which A comprises a three-phase supply for the motor M2, B a lower voltage control circuit supplied by a tapping off one phase of the main circuit and governing the solenoidoperated valves, and C a direct current low voltage circuit supplied through transformers T1, T2 and rectifiers MR1, MR2 and governing relays which control the solenoids. Preparatory to the cycle of operations the piston 6 descends and closes a bottom limit switch 25, so causing the D.C. control voltage of 224 volts to be applied to the coil of a relay R1, through the closed "in" limit switch 26 of the leg 1 and the wiper bottom limit switch 30. The relay R1 closes the contacts R1/1 (locking up over its own contacts R1/2) thereby energizing the contactor C2 and applying the A.C. control voltage of 230 volts to the solenoid of the valve V2, which opens to admit oil to both sides of the piston 6 which therefore rises in consequence of the difference in areas caused by the piston rod 5. Closing of the switch 25 also causes voltage to be applied to the contactor C4 which energizes the solenoid of the air valve V4 to operate the feed head 15. When the piston 6 reaches the highest point of its travel: (i) A top limit switch 24 is moved to de-energize the contactor C4, whereupon the feed head 15 is retracted, and to apply voltage to the contactor C5, through an interlock switch 28 which was closed by the retraction of the feed head. The contactor C5 energizes the solenoid of the valve V5 which causes the wiper plate 4 to descend unobstructed by the feeder 18. (ii) A pilot control valve V8 opens and applies pressure over its capillary to V7 which thereupon operates and opens the top part of the cylinder HC to atmosphere, whereby the full hydraulic pressure is applied to the bottom of the piston 6 and the shoe stiffener is moulded between the leg 1 and the jaws 3. When the wiper plate 4 reaches its bottom position it trips the switch 30 which energizes a relay R2 and de-energizes the contactor C5 and the relay R1. The de-energizing of the contactor C5 causes the wiper plate 6 to be retracted and the de-energizing of the relay R1 opens the valve V2 to atmosphere, at which the pilot relief valve V8 closes, thereby allowing the valve V7 to apply pressure above the piston 6 and return it downwards. As the piston 6 moves downwards it closes a switch 29 which, through the closed contacts R2/1, causes voltage to be applied to the contactor C3 which energizes the solenoid of the leg ejector air valve V3. The leg 1 swings outwards to eject a moulded stiffener and at the limit of its outward travel it trips a switch 27, so de-energizing the relay R2 and the contactor C3 whereupon the leg 1 returns to its rear position and the circuit is restored in readiness for the next cycle. The motor contactor C1 is closed or opened by a pair of press buttons P1. The machine may be rendered inoperative by opening a switch P2, when the motor simply pumps oil through a pressure relief valve V6. The Provisional Specification describes an electrical control sequence by contactors operated by a motor-driven camshaft. The Provisional Specification also describes safety means, i.e. (i) A switch in the circuit which operates the contactor Cl to prevent the motor from being started if the air pressure is too low to operate the equipment, with a lamp which indicates failure in the air supply: (ii) A relay which operates when any contact between the leg and the mould jaws or between the feed mechanism and other moving parts of the machine, causing the machine to stop and an alarm bell to ring.