Patent GB-856254-A (GB)
Title: A new or improved method and apparatus for the production of supporting segments
IPC: B21D7/08
Filed: 1957-03-14
Abstract: 856,254. Photo-electric detecting devices. BOCHUMER GESELLSCHAFT FUR GRUBENAUSBAU UND TECHNIK. March 14, 1957 [March 14, 1956; July 30, 1956], No. 8491/57. Class 40(3). [Also in Group XXII] A method of curving a profiled work-piece over at least part of its length comprises passing the work-piece between at least three parallel rollers, two of said rollers bearing against one side of the work at laterally spaced positions whilst a third roller bears against the opposite side of the work between said laterally spaced positions, and, during passage of the work between the rollers, moving one or more of the rollers transversely of the direction of length of the work so that the work is bent to a form having bending radii varying along its length. A profiled work-piece 6 is passed between bending rollers 2, 3 and 4 and a correcting roller 5 over horizontal guide rollers 7 and 8. The roller 3 and possibly the roller 4 are driven and the rollers 4 and 5 are adjustable transversely of the workpiece during passage therethrough to vary the curvature of the bent work. Means for effecting the adjustment of each roll 4, 5 may be coupled or independent of one another and the adjustment movement may be stopped or reversed as well as accelerated or slowed down. The correcting roller 5 may be adjusted manually and its position may be fixed for a number of different workpieces. The roller 4 is rotatably mounted in a housing 10 moved to and from the workpiece 6 on a guide 11 by a screw spindle 12 engaging an axially fixed nut 13. The roller 5 may be similarly adjusted by a screw spindle 9 the drive of which may be coupled to that of the screw spindle 12 or a separate driving motor may be provided. The nut 13 is rotated by a chain 17 and sprocket 16 from a reversible motor through a continuously variable reduction gear, or from a continuously variable speed motor through a reversible gear. The nut 13, through a sprocket 18, chain 19 and sprocket 20 rotates a nut 21, held against axial displacement, which moves axially a non-rotatable threaded spindle 23. This, at the ends of its travel, engages switch levers 26, 26a of switches 30, 30a to switch off and simultaneously reverse the motor driving the nut 13 and switch in a time relay which acts to switch on the motor after an adjustable period of time. The positions of the switches areadjustable by spindles 32, 32a, axially of the operating spindle 23. The switch 30a may also operate so that the spindle drive in the opposite direction will be at a speed different from that before the motor stopped. The switches 30a and/or 30 may only switch off and reverse the drive, the subsequent switching in of the motor being effected by another switch automatically controlled by passage of the work through the apparatus. A work piece having a central part of small constant bending radius and outer parts of increasing bending radii may be formed. The spindle 23 may also operate adjustable intermediate switches to reverse the motor with a different speed or to stop the motor and then start it again in the same direction with a different speed. The speed of rotation of the adjusting motors for the rollers 4, 5 may alternatively be adjusted using D.C., shunt-wound motors and by switching variable resistances into the primary circuits thereof under control of suitable cam discs. Photo-electric cell means 33, 34 may be arranged to switch on the adjusting spindle motor, if required after an adjustable interval of time, on passage of the front end of the workpiece therethrough. Passage of the rear end may control the adjustment of the rollers 4, 5. A plurality of photo-electric means adjustably spaced along the path of the work may control movement of the rollers 4, 5, for example photo-electric means 33a, 34a may be provided on the exit side of the apparatus. Bending of a workpiece having a straight portion and a curved portion may be controlled by the photo-electric means. The adjustment of the rollers 4, 5 may be controlled by electrical or mechanical switching means operated by the work.