Patent GB-641033-A (GB)
Title: Improvements in machines for bending plates
IPC: B21D5/14
Filed: 1948-04-21
Abstract: 641,033. Angular bending. BIGWOOD & SON, Ltd., J., TINLEY, E. L., and CARTWRIGHT, F. April 21, 1948, No. 10948. [Class 83 (iv)] Relates to a plate-bending machine comprising an upper roll 21 movable downwardly into the space between two lower rolls 14, 15, and to means for relieving the bearing support 19 on one end of the upper roll of the pressure caused by the weight of the roll so as to permit movement of such bearing support and endwise removal of the work at the end of the rolling operation. According to the invention, a ball head 48 on an extension 47 at the end of the upper roll remote from the bearing support 19 is operated by a mechanism driven by an electric motor 53 and adapted to be stopped when the required degree of pressure on the ball head is obtained by means comprising a member 70 which is adapted automatically to be set in motion along a given path by the movement of a slide 50 for applying pressure on the ball head and to open a switch 57 in the motor circuit. The rolls 14, 15 are driven by a motor through gears 81, 82, Fig. 1, and are mounted in fixed bearings in vertical columns 11, 12 which are fixed to the bed 10 of the machine. The top roll 21 is mounted at either end in housings 17, 19, Fig. 4, which are slidable vertically in the columns 12, 11, respectively, by means of a motor 43 driving a shaft 44 which feeds, through worms and worm wheels 27, a lead screw 25 connected to each housing. To facilitate removal of the workpiece from the roll 21, after the bending operation, the housing 19 can be pivoted about a pin 24 on the screw 25 by means of manual or power operation of a pair of links 35 which are pivoted at 37 to the column 11 and have their ends received in slots in the housing 19. The latter power means comprises a motor 42 driving a gear 40 which engages a quadrant pinion 39 connected to the links 35. The extension 47 has a conical part 80, Fig. 5, to carry the ball head 48 which is adapted to be engaged by a recess 49 in the slide 50. Two posts 52 support the slide 50 and these posts are moved vertically by a screw-and-nut drive from the motor 53 which also drives, through gearing 66 and an electrically-operated clutch 64, a control member 63 which is mounted on brackets 61, 62. The carriage member 70 is in threaded engagement with the control member 63 and slidably engages an aligning rod 72 also carried by the brackets 61, 62. An indicator 73 is provided on the carriage 70 to cooperate with an adjustable pressure marker 75 carried by extensions 67, 68 of the brackets 61, 62. In operation, after the workpiece has been rolled, the motor 43 is operated to raise the roller 21 and then the motor 53 is operated to cause the slide 50 to be lowered until the recess 49 contacts the ball head 48 and a switch 77 attached to the carriage contacts the conical port 80 of the extension 47. As the latter switch is closed by the port 80, it. engages the clutch 64 to drive the control rod 63 and causes the carriage 70 to move in the direction of the switch 57. The pressure between the recess 49 and ball head 48 increases until the bearing reaction of the roll 21 at the housing 19 is reduced to zero and the motor 53 stopped by the carriage 70 opening the switch 57. The motor 42 is then operated to pivot the support 19 about the pin 24 so that the workpiece may be withdrawn. In various modifications, the switch 77 may be mounted on a fixed bracket to be actuated by a projection on the slide 50, and the switch 57 may be movable along the control rod 63 and operated by an abutment on the frame of the machine.