GB797354A - Pipe bending machine - Google Patents

Abstract

797,354. Angular bending. HILGERS MASCHINEN - UND APPARATE - BAUANSTALT GES. Jan. 21, 1955 [Jan. 22, 1954], No. 1912/55. Addition to 767,134. Class 83 (4). [Also in Group XXIX] A pipe-bending machine as claimed and described in the parent Specification in which a pipe is bent round an hydraulically rotated bending former to which it is clamped and the trailing unbent part of the tube is guided by a bar or rollers, moved to engage the tube by hydraulic means, is characterized in that a delay valve is provided in pipe lines connecting hydraulic cylinders, operating the bending former and guide bar or rollers, to a control valve controlling the direction of operation of the pistons, so that the guide bar, or rollers, is subjected to pressure before the piston rotating the bending former is moved. Hydraulic pressure medium, e.g. oil, from a pump 10 passes through a magnetically-operated control valve 12 and then, in one position of the valve 12, through a line 16 to a delay valve 17. Oil passes through an inlet port 18 in the valve 17, an annular chamber 19, and an outlet port 21 and thence through a line 22 to move a piston 23, which moves the guide bar or rollers to the right. When the guide bar engages the unbent part of the tube the piston 23 stops and pressure builds up in the valve 17 against an annular piston face 20d, to lift a piston. 20 therein against an adjustable spring 27, to open a passage 26 to the oil under pressure. Oil then passes through a pipe 25 to move a piston 15, which rotates the bending former, downwards. For bending in the opposite direction the control valve 12 directs pressure oil through a line 32 against the other faces of the pistons 23 and 15, pressure against a piston face 20c this time lifting the piston 20 of the delay valve 17 after the piston 23 has been actuated.