Patent GB-1500243-A (GB)
Title: Tube welding machines adjustable to accommodate tubes of different lengths
IPC: B23K9/12
Filed: 1976-03-05
Abstract: 1500243 Welding by fusion MESSER GRIESHEIM GmbH 5 March 1976 [5 March 1975] 08909/76 Heading B3R In a machine for welding tubes 18 (e.g. for the welding of flanges to the ends thereof) comprising a fixed headstock 14 (Fig. 1) and a tailstock 16 longitudinally adjustably movable to accommodate tubes of different lengths, the tailstock carries a device 26 whlch senses the lengths of tubes and accordingly controls tailstock adjustment movement. As shown, each tube is longitudinally fed to the machine on parallel track rollers 22 until its front end abuts a headstock-aligned stop 24, whereupon the device 26 senses the rear end, and hence the length, of the tube. The head and tailstocks are provided with adjustable torches and clamping means (not shown). As shown in Fig. 3, the sensing device 26 comprises a holder 30 which is clampable at 34 to a tailstock cross-member 28 and supports guide rollers 38 and an actuating cylinder 48. A member 40 is guided by the rollers 38 and is fast, via a plate 42, with the piston 50 of the cylinder 48 for vertical movement thereby. A mounting 62 is guided by a pin 60 for vertical movement between the plate 42 and an abutment 70 also fast with the member 40. A spring 66 downwardly biases the mounting into engagement with the plate 42. A sensing arm 82 provided with a tube-engaging roller 84 is pivoted on the mounting 62 and leftwardly biased by a spring 86. Switches (52), (54) fast with the holder are respectively actuable by cams 56, 58 on the member 40; a switch 72 is actuable on upward movement of the member 62 against the spring 66; and a switch 90 is actuable by a cam 88 on the pivot end of the sensing arm 82. The switch (54) is operable in the uppermost position of the member 40 to signal for feed of a tube up to the stop 24. In operation, in changing over to a longer tube fed up to the stop 24, as in Figs. 5, 6, not shown), the cylinder 48 is energized to depress the member 40 and when the roller 84 engages the periphery of the tube the mounting 62 is raised with respect to the member 40 and consequent actuation of the switch 72 effects rightward movement of the tailstock 16. When the roller 84 drops over the end face of the tube it allows downward movement of the mounting 62, deactuation of the switch 72 and the stopping of the tailstock in its appropriate position. On tailstock stoppage, a valve is actuated to energize the cylinder 48 to return the member 40 to its uppermost position. In changing over to a shorter tube as in Figs. 7, 8, not shown), the member 40 is depressed, and since the roller 84 does not encounter the tube, a switch (52) is closed by the cam 56 and effects leftward movement of the tailstock 16. When the arm 82 engages the tube end it is pivoted to actuate the switch 90 whereby the tailstock is stopped in its appropriate position. A further control pulse, produced by the switch 90, optionally after a delay, effects energization of the cylinder 48 to return the member 40 to its uppermost position. An alternative embodiment (in Fig. 6, not shown), the pivotal connection of the arm 82 is replaced by a horizontal sliding connection.