Patent GB-584275-A (GB)
Title: Improvements in or relating to machine for welding can bodies
IPC: B23K11/06
Filed: 1944-07-14
Abstract: 584,275. Welding can bodies. CONTINENTAL CAN CO.. Inc. July 14, 1944, No. 13534. Convention date, Sept. 4, 1943. [Classes 83 (ii) and 83 (iv)] An apparatus for spot welding can bodies comprises a horn over which the body passes and welding electrodes moved into and out of contact with the body to engage the outer face thereof in the region of the lap portion of the seam, one of the electrodes being of shape to conform to the contour of the body and the other being a rotatable disc making point contact with the outer lap portion. The apparatus may form part of a machine as described in Specification 296,970, [Class 83 (ii)], wherein the body blanks after notching and providing with hooks are first bent round the horn and the hooks interlocked and bumped to form the side seam. The welding of one or both lapped portions of the seam is then effected and the body finally fed to mechanism for soldering the side seam. The horn 1 over which the body is bent and the seam bumped by an iron 2 has a rigid extension 5 which is further supported by a plate 6 pressed up by a spring 18 and withdrawn to allow the bodies to be discharged therefrom by a cam 17 and lever mechanism 16-8. The welding mechanism comprises a supporting head 19 adjustably mounted on a rod 22 which is raised so as to bring the electrodes 20, 21 into contact with the outer side of the body by a cam 28 and lever 25 against the action of a spring 29. The electrode 21 which engages the inner side of the lap and is of shape conforming to that of the body is mounted on the ball end of a stem 32, Fig. 4, carried by a member 31 which is yieldingly mounted as by an adjustable spring 38 on the head 19. The member 31 is connected by a lead 41 with one terminal of a transformer. The other electrode 20 consists of a disc which is rotatably mounted in a bracket 43 secured to a support 44 which by a bolt 44a, Fig. 5, and washers 48, 49 is secured to but insulated from a plate 45 yieldingly mounted by a spring 52 on the head 19. The upward motion of the plate 45 is limited by a stop 54 secured to the head 19. To the support 44 is secured the lead 50 connected to the other terminal of the transformer. Each time the head 19 is reciprocated towards and from the work, the electrode 20 is rotated on its axis by a spring-pressed dog 58 on a fixed arm engaging a ratchet-wheel 59 on the electrode axis 42. The ratchet-wheel is spring-pressed into frictional engagement with the bracket 43 to ensure current supply to the electrode. In operation, when the cam 28 raises the head 19 so as to bring the electrodes into contact with the work, a second cam 63, Fig. 2, on the shaft 28a puts in the main welding switch 62. An auxiliary switch 68, Fig. 9, is provided in the welding circuit which is closed by the blank engaging the lever 69 so that if no blank is present the circuit is not completed. The blanks when fed over the horn 5 are located by end gauges 73 which are mounted on pivots 74 and are raised out of the way prior to the ejection of the body by a cam on a shaft 83 which through lever mechanism 81-78 operates a shaft 77, Fig. 8, connected by a bevel gear 76, 75 to the pivots 74. Fingers 85 carried by arms 86 pivoted on a cross-shaft 87 are also provided which in the event of the hook portions of the seam not being properly closed, engage the ends of the body and thus open a switch 89 in the motor circuit to stop the motor.