Patent GB-554661-A (GB)
Title: Improvements relating to welding machines
IPC: B23K11/093
Filed: 1942-01-08
Abstract: 554,661. Electric welding. CHICAGO METAL HOSE CORPORATION. Jan. 8, 1942, No. 323. Convention date, March 10, 1941. [Classes 83 (ii) and 83 (iv)] In a resistance welding machine, particularly for welding the cap 136 to a corrugated tube or bellows 135, one of the electrodes is carried by an auxiliary head frame movably mounted on a main head frame itself movably mounted upon a stand of the machine separate means being provided for moving the main head frame relative to the stand and the auxiliary frame relative to the main head frame. The main head frame 45, which is pivoted on the stand 10 and is moved by a pedal 54 against the action of an adjustable spring so as to bring the movable electrode 12 into the vicinity of the work where it is held by a spring- closed latch 55, carries a slide 63 vertically adjustable by a screw 64 and a support member 61 laterally movable by a screw 66. To the member 61 at 62 is pivoted the arm 68 of the auxiliary frame 46 carrying a pedestal 69 for the roller electrode 12 of a front plate 70. The electrode 12 is secured by nuts 104, 108 on a shaft 100 mounted on roller bearings in the pedestal. The frame 46 is moved about the pivot 62 so as to - bring the electrode into contact with the work by a bellows 71 communicating with an air supply 89 through a pipe 86 provided with a pressure gauge 114 and an adjustable reducing valve 140, and an inlet valve 91, the valve 91 and the exhaust valve 93 being controlled by a spring- returned pedal operated lever 94. The frame 46 is returned by an adjustable spring 73 and is provided with an adjustable stop 72 for limiting clockwise movement and an adjustable stop 82 for limiting counter-clockwise movement. The co-operating electrode 11 is secured in a hollow shaft 14 rotated on pedestals 16, 17, 18 on a subframe 10a by a replaceable gear 19, 28, and worm and bevel gear from a shaft 22 driven by an electric motor 20 through a belt and clutch 21. The shaft 100 of the electrode 12 is provided with a flange 106 dipping in a mercury bath 107 connected to one terminal of a transformer 114 through copper strips 110 anchored at one end thereto and at the other end to the line 113. The bath may be replenished through a filling plug 108. The electrode 11 is connected to the other terminal of the transformer through a rotatable collar 31 fixed on the shaft 14 between felt rings 32, 33 adjusted by collars 34, 35, the collar 31 dipping in a mercury bath 36 replenished through a filler cap. The bath is formed in the pedestal .17 which is electrically connected to the transformer via the frame 10a. The line 113 contains a spring-opened switch 117 closed by a bellows 118 connected to the fluid supply line and provided with a dash-pot 119. The clutch 21 is operated by an electromagnet 137 in the welding circuit. In operation, the motor is started and the frame 45 first moved about its pivot by operation of the pedal 54. The pedal 96 is then pressed to open the valve 91. The bellows 71 is thus first operated to bring the electrode 12 into contact with the work, the closing of the switch 117 being delayed by the dash-pot 119. On closing of the switch 117 the welding circuit is energized and the electromagnet 137 operates the clutch 21 to drive the electrode 11. At the end of the welding operation the pedal 96 is released and the switch 117 opens prior to withdrawal of the electrode 12. The electrode 11 and work are cooled by fluid ejected through nozzles 40 from a channel 41 in the shaft 14 connected to a stationary flexible hose 42 by a connection 43. The profile of the electrode 12 is maintained by a scraper blade 128 pressed down by an adjustable spring 130 in a support 125 mounted on the pedestal 69.