GB659122A - Machines for bending sheets and plates of metal - Google Patents

Abstract

659,122. Angular bending. RHODES, C. J. April 4,1949, No. 9149. [Class 83 (iv)] [Also in Group XXIX] In a hydraulic machine for bending metal plates the beam 5 carrying the movable tool 4 is automatically slowed down at selected distances from the bottom of its stroke by means which control the hydraulic system and are adjustable with respect to the beam. The invention is preferably applicable to the machine described in Specification 640,605 in which the beam 5 guided by slides 6, 7 on the frame 1 is actuated by a doubleacting ram 22 through a push-rod 20 carrying a pair of collars 19 operating toggles 12 through links 14, 17. Pressure-fluid is directed to either end of the ram 22 by a control valve 38 which has one position in which it gives a constricted flow for the downward stroke of the beam. For the downward stroke the spindle 37 of the valve 38 is depressed against a spring by foot or hand levers 24, 45 on a shaft 23 connected to the valve through a push-rod 28, Fig. 4, levers 29, 31 interconnected by a latch 30, push-rod 32 and levers 33, 35, Fig. 1, on a shaft 34. The lever 29 is cranked downwards and carries a roller 40 which is moved by a cam 41 on the beam as it descends and shifts the control valve to the position in which the flow of oil is constricted and the rate of descent of the beam thereby reduced before the tool 4 engages the work. As the beam reaches the end of its stroke a cam 39 attached thereto releases the latch 30, allowing the valve to return under the action of the spring to its normal position in which the oil flows to the opposite end of the ram so that the beam is thereby raised. The cam 41 has a rack 43 and is vertically adjustable on the beam in guides 42 by pinion 44 on a shaft 45 which is rotatable by a lever 46 reading against a graduated dial 48 and which may be locked in any position by a spring-loaded plunger 47.