GB1287870A - - Google Patents

Abstract

1287870 Angular bending C U PEDDING- HAUS 20 Nov 1969 [23 Nov 1968] 16057/72 Divided out of 1286865 Heading B3E [Also in Division G3] Reverse elastic travel of a bar, which has been bent to a predetermined angle by a rotatable platen having a pair of bending tools coacting with a stationary bending tool, is compensated for by continuing the bending through a supplementary angle which is determined by measurement of the current consumption of an electric motor driving the platen in the elastic deformation range of the bar being bent. In the embodiment shown in Fig. 3 the platen motor 28 is coupled to a control motor 36 by an electromagnetic clutch 35. During the bending of the bar a wiper 38 copies the traversed angle of rotation of the motor 36 on a slipring 39. The wiper 38 is stopped when the circuit of the clutch 35 is interrupted after the excitation of a relay 33 due to current consumption of the motor 28 reaching a preset value. Simultaneously a limit switch 41 is actuated to connect the motor 36 to a voltage source 34 and so cause the wiper 38 to reverse upon the slipring 39. A relay 27 will thus remain activated and so maintain the motor 28 switched on for the duration of the return run of the motor 36. In the embodiment shown in Fig. 4 a capacitor 45 is charged with respect to time until a preset current flow is reached at which time a contact 44 opens. When the predetermined angle is reached a limit switch 41 is operated to discharge the capacitor 45. A relay 50 corresponds to the operating resistance of a transistor 48 and provided sufficient current flows maintains the contact 51 for the circuit of the relay 27 in the closed position.