Patent GB-575707-A (GB)
Title: Roller machine for bending sheet metal
IPC: B21D5/14
Filed: 1944-02-28
Abstract: 575,707. Control of motors; actuation of switches. CAIRNS CORPORATION. Feb. 28, 1944, No. 3684. Convention date, Feb. 8, 1943. [Classes 38 (iii) and 38 (v)] [Also in Group XXII] A machine for bending metal sheets comprises driven feed rolls 14, 15 and a roll 29 selectively moved towards or away from them bv separate adjusting means, driven by electric motors, at each end of said roll, the switches for controlling the two motors being operated by cams 50, 51 moved by the rotation of the rolls 14, 15. The roll 14 is driven by gearing 20, 21, 23, 24, 28 and an electric motor 27 and the roll 15 is adjustable for thickness of the work by screws 19. The roll 29 is journalled in semi-spherical bearings 30 in blocks 31 which are each adjustable in inclined guides 32 by a screw 46 which is rotated by a motor 33 or 34 and gearing 35, 36, 42. Damage is prevented by limitswitch arms 72, 73 in the path of a collar 74. The cams 50, 51 are carried by a carriage C, Fig. 3, moved horizontally by a cord 65 wound around a drum 66 on the shaft of the roll 14 and passing over guide pulleys. The cams 50, 51 move cam members 53, 54 laterally and these act on rollers 56a, 56b, 57a or 57b of switches in boxes 56, 57 to cause forward or backward rotation of one or both of the motors 33, 34. The resultant movement of one or both blocks 31 causes, by means of linkwork 59 ... 64, a movement of one or both switch boxes 56, 57 in the same direction as the members 53, 54 have previously moved so that all the switches in the boxes 56, 57 are brought to open position and the motors 33, 34 to rest. Limit switches 114, 115, Fig. 3, may also be provided to be operated by excessive movement of the carriage C. The motor 27 may be controlled by three press-button switches of which 84d and 84e, Fig. 4, 4a for forward and backward movement, are normally open and a stop switch 84f is normally closed. When 84d is operated it energises a solenoid 86a to close all the contacts of a switch 86 which, in turn, energises solenoids 69a and 102a and complete a circuit through switch 84f and the solenoid 86a to hold the switch 86 when the switch 84d is released. The solenoid 69a lifts the friction shoe 69b of a plugging switch 69 out of contact with the shaft 27a of the motor 27 and the solenoid 102a moves a relay switch 102 to connect the three mains 80a, 80b, 80c to the motor 27 to cause forward rotation. If instead of 84d the switch 84e is operated, switches 93 and 100 are moved to lift the shoe 69b as before and start the motor 27 but in the backward direction. The limit switches 114, 115 are normally open and when either is closed by excessive movement of the carriage C it energises the solenoid 109d or 88d of relay switch 109 or 88 to open the circuit through the solenoid 93b or 86a. This can also be done by pressing the switch button 84f. When the circuit through either of the solenoids 93b or 86a is thus broken the corresponding relay switch 100 or 102 reverts to normal position cutting off the current to the motor and allowing the shoe 69b to fall on to the rotating shaft 27a. According to the direction of rotation of this the shoe is moved to the right or left thus closing contacts 69e, 69d or 69c, 69f to energise the solenoid 100d or 102a and reverse the torque in the motor. As this comes to rest an overload relay 98 or 112 operates to deenergise the solenoid 100d or 102a and prevent reverse rotation. When automatic actuation of the motors 33, 34 is desired a switch 124 is moved to close contacts 124a, 124b. If then the cam 53, Fig. 1, raises the roller 56a, the corresponding switch 56m, Fig. 4a, is moved down to close contacts 50f, 56g and energise a solenoid 133a. This closes the contacts of a switch 133 which in turn causes the shoe of a plugging switch 70 to be raised from the shaft of the motor 33 and this to be rotated in a forward direction by closing the switch 139. Raising the roller 56b similarly causes backward rotation of this motor by means of switches 56c, 150 and 141. Lowering of the roller 56a or 56b causes the motor 33 to be brought rapidly to rest by means of the plugging switch as in the case of the motor 27. The switches in the box 57 similarly operate the motor 34. When hand operation is desired the switch contacts 124a, 124c are closed and then the press-button switches 170, 171, 176 and 177 act in place of the switches 56 and 57. By closing a switch 190 the limit switch 115 may be used to reverse the motor 27 and return the carriage C to its initial position automatically. If a hand switch LS is closed then as soon as one of the rollers 56a, 56b, 57a, 57b, is allowed to fall, by movement of the member 53 or 54, beyond that corresponding to the open position of the appropriate switch, this is moved up to connect the conductors 123, 126, energise a solenoid 96g, and move switch 96, thus stopping the motor 27 without de-energising the solenoids of the relays 86, 93 so that the motor 27 restarts directly the conductors 123, 126 are not connected by any of the switches in the boxes 56, 57.