Patent GB-847540-A (GB)
Title: Automatic shift two-speed press brake
IPC: F16D65/28
Filed: 1957-11-25
Abstract: 847,540. Angular bending. CINCINNATI SHAPER CO. Nov. 25, 1957 [Dec. 3, 1956], No. 36716/57. Class 83 (4). [Also in Groups XXIV and XXXIV] A machine tool flywheel is clutchable to a disc splined to a main shaft, or to a second clutch disc splined to a sleeve connected by reduction back-gearing to the main shaft. The flywheel 10 of a two-speed press-brake is carried on beaiings 12 on a main-shaft 13 which has a pinion 14 meshing with a gear 15 on an intermediate shaft 16 carrying a pinion 17 meshing with a gear 18 on the eccentric shaft 19 of the press. The end of the shaft 13 is splined to receive a clutch plate 20 engageable by clutch plates 21, 22, carried by the flywheel, on inflation of a bladder 23 supplied by pipes 25, 25a from a selector valve 41. Similar clutch plates 33, 34 rotationally rigid with the other side of the flywheel can engage a clutch plate 27 on inflation of a bladder 35 through pipes 40, 40a from the valve 41. The clutch plate 27 is splined to the end of a sleeve 26, free for rotation on the shaft 13, carrying a gear 28 which drives a reduction back-gear 29, 31 on a sleeve 30a rotatable on a shaft 30, the gear 31 meshing with a gear 32 rigid with the shaft 13. The end of the shaft 13 remote from the flywheel carries a brake disc 58 engaged under the pressure of springs 61 by brake plates 59, 60, the brake being disengaged by inflation of a bladder 57 supplied from a valve 55 controlled by a solenoid 56. A pipe 50 supplies air from a pressure source to the valve 55 and to a clutch control valve 51 operated by a solenoid 52, the valve 51 passing air to the valve 41 which is controlled by a solenoid 53. A chain and sprocket drive 63, 62 drives a camshaft having four cams, adjustable for dwell and timing disposed within a housing 60, the cams operating four switches designated cam 1, 2, 3, 4 on Fig. 5. A selector knob (not shown) controls five switches, 1, 2, 3, 4, 5 to five different combinations in the manner set out in Fig. 6 to provide five modes of operation of the control system. With the operator's foot switch 80 released a circuit is established through a non-repeat coil 82 to close switches 82a, 82b. Depression of the switch 80 establishes a circuit through solenoids 52, 56 to engage a clutch and release the brake; the solenoid 53 passing air to the low speed clutch when it is energised, and to the high speed clutch when it is energised. Closing of the switch 80 also energises a constant run coil 83 which opens switch 83a and closes switch 83b. An automatic return coil 84 when energised opens a switch 84a and closes a switch 84b. If the selector is placed to position O and the switch 80 depressed the machine will operate at low speed. for the duration of the depression of switch 80 and may be stopped in any position. With the selector at A, the ram will descend at high speed under the control of switch 80, until the cam switch 3 closes, usually a few degrees after the bottom of the stroke, then the ram will be automatically returned to the top of the stroke, at which point the high speed clutch will be released and the brake applied. With the selector at B a similar operation at slow speed is attained. With the selector at C or D the ram will descend at high speed until cam switch 1 closes near the bottom of the stroke, whereupon the ram will continue to descend at slow speed for a period dependent on the dwell of cam 1, then high speed will be re-engaged for the remainder of the return stroke of the ram. The two positions C and D providing different dwell periods for the slow speed operation. The clutches and brake, may be electrically or hydraulically operated as an alternative to the air operation described.