| 摘要 |
939,334. Welding by pressure. ATOMIC ENERGY OF CANADA Ltd. May 8, 1962 [May 9, 1961], No. 17725/62. Class 83 (4). In a resistance welder comprising fixed and movable electrodes, means to apply an initial pressure to the movable electrode and conductors positioned parallel to one another and connected in series to supply weld current to the movable electrode so that weld current flowing through the conductors tends to move them apart to apply pressure on the movable electrode, a magnetic core encircles the conductors. The movable electrode 35, Fig. 1, is carried on the piston-rod of a pneumatic or hydraulic cylinder 20 and welding current from a source 12 is supplied to the electrode by parallel conductors 44, 46 and bus-bar 45 while current is supplied to the fixed lower electrode 16 by conductors 18, 19. The conductor 46 is flexible to allow movement apart of the conductors 44, 46 which are surrounded by a magnetic core 40 to concentrate the flux. Both conductors or only the connecting portion may be flexible and a control winding or windings may be provided on the core. In operation the electrode 35 is pressed on the work by the cylinder 20 and when welding current flows the conductors 44, 46 are urged apart to increase the pressure on the work. In a modification, the upper busbar is bifurcated to accommodate the piston-rod and two U-shaped flexible conductors are provided, one on each side of the piston-rod, to extend from the bus-bar to a connector carried on the piston-rod. Each U-shaped conductor is surrounded by a magnetic core. Instead of a U-shaped conductor, a rigid upper conductor connected to a lower flexible conductor may be used. A single control winding on the magnetic core may saturate the core to decrease the intensifying effect thereof but two windings may be used to increase the intensifying effect. In another embodiment the piston-rod 23c, Fig. 4, slidably receives a rod 67 on the electrode holder 33a with a rubber washer 75 between the rod and holder. Upper conductors 71 secured to the rod are connected by flexible conductors 72 to lower conductors 73 carried on the holder 33a. Cores 40d surround both conductors 71, 73. In operation the rod 23c is moved to apply pressure to the work and when welding current flows the conductors 71, 73 repel to increase the pressure. The washer 75 may be omitted using the air above the rod 67 as a cushion. |
