GB1150525A - Method and Machine for Form Rolling - Google Patents

Abstract

1,150,525. Rolling tubes. NATIONAL ACME CO. 11 July, 1967, No. 31954/67. Heading B3M. A rolling machine, for forming annular or helical ribs on tube, includes a carriage 26 which supports one end of a tube 21, and which is driven by a motor longitudinally relative to both a frame 25 and a fixed roll-carrying head 40, the motor being controlled to move the tube through the head at a speed equal to the feeding movement imparted to the tube by the rolls of the head, thereby avoiding axial loads on the rolls. In operation, a movable support 61, Fig. 5, for a mandrel 60, together with a tube length sensor 66, is moved to the right by a pneumatic cylinder until the mandrel reaches the carriage 26 within which one end of the tube 21 is clamped. The carriage is then moved to the left by a fluid motor 29, Fig. 17, which operates a rack and pinion drive, at a controlled feed rate set by a micrometer adjustment 83 which controls the opening of a servo valve 33. When the tube end contacts the sensor 66 a cam on the sensor releases a contact 74 and the rolls on the head 40 contact the tube. Each roll 48, Fig. 1, is carried in a block which is spring urged outwardly, the head being rotated by a motor 42. Axial movement of a sleeve 52 moves the rolls towards and away from a tube due to the contact between rollers 53 on the sleeve and cammed surfaces 54 on the blocks. To form helical ribs each roll is formed by annular discs skewed relative to the tube axis or, alternatively, is formed with a helical contour and is not skewed. To form annular ribs and still cause feeding of the tube, each roll can have a helical contour and also be skewed. As the rolls contact the tube the rolls positively feed the tube forwardly, preferably at a higher rate than previously. The head 73, Fig. 17, is then pulled by the tube to the left, resulting in movement of the valve spool 35 and consequential speeding up of the motor 29. The carriage is therefore driven at a speed dictated by the feed applied by the rolls to the tube. Further contacts 74 cause the rolls to the released from the tube and an unfinned land to be produced on the tube. During each such release, the mandrel 60 which has been frictionally moved out of contact with the head 73 during rolling, is moved to the right under the continuing, but normally overridden, action of the pneumatic cylinder. The finished tube is moved by the carriage to the right and removed from cantilevered supporting rolls 37.