Patent GB-566226-A (GB)
Title: Improvements in machines for bending tubes, bars and the like
IPC: B21D7/022
Filed: 1943-07-10
Abstract: 566,226. Angular bending. VICKERSARMSTRONGS, Ltd., and EASTES, J. C. July 10, 1943, Nos. 11210/43 and 5937/44. [Class 83 (iv)] A machine for bending tubes, bars, &c. comprises two dies in tandem through which the work is passed, the first being stationary and the second movable about two axes inclined to each other and to the longitudinal axis of the work so as to be capable of universal pivotal movement about said axis, together with means for moving the pivoted die and means for impelling or drawing the work through the dies during bending. The work 20 is secured to a collet chuck 24 or to a tubular chuck carried by a spindle 60 in the saddle 62 of a feed carriage 71, 72, the saddle having a halfnut engaging a lead screw 63 which is rotated in bearings 64 and intermediate bearings 641 by a rotary hydraulic motor 67 supplied with fluid by a pump 401 driven by an electric motor. The work during traverse is supported by a number of steadies 22 each comprising a transversely movable slide 222 with arcuate pad 223, the slide having pivoted thereto at 224 a lever 225 with work-engaging cap .233, the lever being connected by slot 227 and pin 226 to a hand lever 228 connected by a link 229 to a fixed pivot 230. The pin 226 is connected by a spring 231 to a fixed pin 232. In the position shown, Fig. 11, the pin 226, lever 228, link 229 and pivot 230 form a braced toggle which is broken when an abutment on the carriage engages an incline 235 on a lug on the hand lever so as to raise it and allow the spring 231 to retract the slide out of the way of the carriage. The work passes through a fixed die 21 and through a die carried by a spherical housing 25 which is pivoted at 26 to the arms 27 of a carrier 28 mounted on a vertical spindle 29 supported by a bracket 30, the spindle being received in a socket of the ram 33 of a reciprorating motor 31 having a cross-head 34 connected by links 35 to pins 36 on the die 25 which may thus be moved about the axis of the pivots 26. A movement of the die about the axis of the spindle 29 is effected by an hydraulic reciprocating motor 37 through a ram 38, lever and link. The reciprocating motors consist of cylinders in which work pistons fixed to tubular rams within which are slidable piston valves which operate so that a certain degree of movement thereof produces a corresponding degree of movement of the rams in the same direction. Fluid is supplied to or exhausted from the valves by flexible tubes 43, 44 and 52, 53 connected through a pipe 455 with check valve 458 and through a return pipe 460 to a pump 451 with relief valve 453 driven by an electric motor. The valves may be operated by hand or may be pressed by springs against cams 55, 46, preferably in the form of cam plates secured on drums, respectively carried by a cam-shaft 50 and by a shaft 47 connected by spur and bevel gear to the cam-shaft 50. This shaft 50 is driven by worm and spur gear from the motor 67. The speed of the motor 67 is reduced during the formation of bends on the operative stroke of the carriage by a cam 108, Fig. 3, on a shaft 109 geared to the shaft 50, the cam operating a rack 106 geared to a quadrant 105 on a shaft 104 carrying a lever 103 which through a connecting rod 102 and lever 101 controls a regulator valve 100 through which the fluid is supplied from the pump 401, Fig. 13, to the pipe 421 connected to the motor 67 through a relief valve 404 and valves 405 and 415. Simple bends are produced by moving the die 25 about one of the axes, and compound or helical bends by a simultaneous movement about both axes. In making a number of bends in different planes, such as in making a tubular chair frame, each bend may be made by moving the die 25 about the same axis, the work being rotated by hand or power between successive bending operations. For this purpose the carriage 71, 72 carries a hydraulic reciprocating motor 70 which is supplied with fluid by a pump 90 operated by an electric motor 132 through gearing 131, 130, 96, 95. The ram 80, Fig. 8, of the motor 70 is formed as a rack 81 which, through gearing 83, 84, rotates the work when the bowl 87 or lug 88 at opposite ends of the valve 85 are.engaged by cam-like kicker plates 86 bolted to the framing. The amount of rotation is indicated by a pointer 92 moving over a dial 91. When the motor is out of action, pressure is returned to the reservoir 481 through a relief valve 483. The machine is provided with a master pilot valve 412 controlled by a lever. With the lever in position A the pump 401 returns the fluid through check valve 407 and pipes 408, 409 to the reservoir 400. When the lever is moved to position B, the valve 405 moves to the right and the fluid passes through pipe 406 to valve 415. The valve 415 is controlled by pilot valve 418 and is moved down when the lever of the latter valve is at position C, so that the fluid from the pipe 406 passes through pipe 421 and speed regulating valve 100 to rotate the motor 67 so as to traverse the slide 62 forwardly. When the end of the stroke is reached, an abutment 424 engages the dog 423 on the pilot valve lever 418 to bring it to neutral position to stop the traverse. The work is then removed, the spherical mounting of the die allowing the latter to accommodate itself to the forwardly moving work without further deformation thereof. The lever is then turned to position D so that the valve 415 is reversed and the slide returned at full speed, the fluid from the pipe 421 returning to the reservoir via the oneway valve 425. When the slide reaches its rear end, a valve 427 is operated by an abutment 426 so as to unload the relief valve 404 and permit fluid in line 403 to return, freely to the reservoir and thus stop the motor 67. The motor 67 may also be stopped at any desired point of the return stroke by an adjustable dog 432 on the cam 108 which engages a pressurerelease valve 431. The motor 67 may also be stopped at any position by moving the lever of valve 412 to .position A. The motors 31, 37 are controlled by the rear bank of the pilot valve 418 so that they are only operated when the lever is in position C.