GB1502001A - Method and apparatus for bending metal pipes bars or rods - Google Patents

Abstract

1502001 Bending tube or rod DAIICHI KOSHUHA KOGYO KK 23 July 1975 [30 May 1975] 30879/75 Heading B3E An elongate metal workpiece to be bent is advanced through an annular heater, then immediately through a cooler, part of the workpiece being secured to an arm pivoted about an axis lying in the place of the heater, and means is provided to alter the angle between the direction of feed and the line from the arm axis to the heated portion of the workpiece, so that the workpiece is bent to a constant radius. In Fig. 3, the direction of feed of a pipe is displaced by an angle # 2 , increasing the bending occurring at the heating point A, so that after the pipe is released, it springs back to a bend radius R corresponding to the length of the arm, or to a lesser radius if required. In Fig. 4, the heater 5 and heating point are displaced along the axis X-X<SP>1</SP> of pipe feed to a point A<SP>1</SP>, AA<SP>1</SP> subtending angle # 2 at O, the arm axis. In each case, the amount of correction applied may be automatically adjusted to correct for detected departure from the required curvature. Fig. 6 shows a device for detecting deviation from the required curvature, rolls 119 and 120 on detector 117 being applied to the pipe by hydraulic cylinder 122, while the position of roll 118, compared with that of an adjustable datum 126, operates a device 129, producing a control signal 130. This signal may be used to displace feed rolls laterally of the pipe to produce appropriate correction of the degree of bending, or may shift the rolls along the pipe while applying a constant load to vary the displacement of the rear end of the pipe.