Patent GB-1028317-A (GB)
Title: Hydraulic die cutting press
Inventor: LISCHER GEORG
IPC: B26F1/40
Filed: 1962-11-29
Abstract: 1,028,317. Cutting-out presses. MASCHINENFABRIK MOENUS A.G. Nov. 29, 1962, No. 45244/62. Heading B4B. An hydraulic die cutting press comprises an hydraulic servomotor within the machine standard to effect power operation of the cutting stroke and power-operated return of the platen, in which a multi-way solenoid valve is provided with a control slide having several pistons and associated ports, one to supply pressure fluid for descent of the platen to the pressure cylinder and another for return of the hydraulic medium from the return cylinder to the solenoid valve. As described two hydraulic conduits 24, 50 in the machine standard, one connected to the cutting pressure cylinder 30, 32 and the other to a return cylinder 54 provide reversal of the hydraulic flow automatically through the solenoid valve 18. Operation of a switch 22 energizes the solenoid 18<SP>11</SP> pushing the slide 20 to the left, oil from the pump 16 flowing through pipe 3, conduit 24 and passage 28 into chamber 30 of the cylinder 32 forcing the piston 34 and the column 36 with the platen 38 downwardly. When the platen 40 has forced the die 42 through the workpiece 44 an electric contact between the platen 40 and the work support 46 is made, which energizes solenoid 18<SP>1</SP> and 18<SP>11</SP> is deenergized, slide 20 moving to the right. Fluid now flows via pipe 4 and conduit 50 and passages 52 of the lower cylinder 54 forcing cylinder 32, piston 34 and the column 36 and platen 38 back to its original position. A contact is again closed reversing the solenoid valve and the slide 20 assumes its pressureless position. The cutting height of the platen is controlled by providing at the upper end of the spindle 26 a cone 60 which remains stationary with the spindle; a spring controlled contact-rod 62, Fig. 2 (not shown), passing through a slot in the cylinder 54, traverses the zone with a wheel, and the other end of the rod acts on a switch 64 adjustable by a knob 66. The knob controls, through gearing 68, a screw spindle 71 to adjust the spacing between a contact pin 72 and the switch contacts, so that when the platen moves upwards the fixed zone engages the moving wheel and energizes the switch and thence the solenoid valve. Two staggered switch contacts, Fig. 3 (not shown) may be provided so that if, during a rest period the platen moves downwards slightly due to its own weight and leakage in the packings the second contact will be energized and the platen will be returned to its correct height. The stroke may also be controlled by a cone instead of a conductive platen and work support; and by the use of a double cone 100, Fig. 4 (not shown) both stroke and height may be simultaneously controlled, by upper part 100<SP>1</SP> and bar 101 and lower part 10011 and bar 102 respectively, co-operating with adjustable switches 104<SP>1</SP>, 104<SP>11</SP>. The cutting-height adjustment means may be disconnected by operation of a knob 126 actuating a clutch 124 so that the spindle 120 is not displaced. In a modification the stroke and height adjustments are provided by separate knobs and transmissions, the clutch being omitted; Fig. 7 (not shown).