| 摘要 |
1,225,016. Welding by pressure. BUDD CO. 26 July, 1968 [26 July, 1967], No. 35876/68. Addition to 1,164,507. Heading B3R. A welding gun comprises a first electrode 62 mounted on a yoke 18 pivoted to a support 12 slidable in a fixed bracket 10, a second electrode 58 mounted on the piston of a cylinder 22 carried on the yoke, a cam bar 32 slidably mounted on the yoke and connected to the piston to cause tilting of the yoke in co-operation with rollers 44, 46 on the support 12, a spring between the fixed bracket 10 and the slidable support 12 and a cam surface 80 on the bracket 10 co-operating with a cam follower 78 to bias the slidable support 12 downward relative to the bracket 10, the arrangement being such that the cam follower 78 is freed from the cam surface 80 in the welding position to allow the electrodes to be floatingly supported by the spring. Alternatively instead of the surface 80 and follower 78, a pin on the cam bar engages a block fixed on the bracket 10. The bracket 10 is secured to a wall &c., the support 12 is in the form of a bar slidable between rollers 14, 16 on the bracket and the yoke 18 pivoted at 20 to the bar 12 clamps the cylinder 22 from which extends a piston-rod 26 carrying the electrode 58 and the cam bar 32 slidable between rollers 38, 40 on the yoke and the rollers 44, 46 on the bar 12. The cam bar 32 has a plane surface 36 engaging the rollers 38, 40 and cam surfaces 48, 50, 52 engaging the rollers 44, 46. A balance spring is arranged in the bar 12, its upper end bearing against screw 86 and its lower end against pin 84 secured in the bracket 10. A link 74 has one end pivoted to the lower end of the bar 12 at A, its upper end carrying a roller 78 contacting the surface 80 of the bracket 10, and a link 76 has one end pivoted to the link 74 and the other end pivoted to the cam bar 32 at B. In operation with the gun in the stored position as shown in the Figure, fluid pressure is supplied to the cylinder 22 to move the pistonrod 26 downwardly, this moving the cam bar 32 over the rollers 38, 40, 44, 46 to tilt the yoke into a vertical position. During this pivotal movement roller 78 is caused to move over the surface 80 towards the left in the Figure. Further downward movement of the piston-rod 26 moves the electrode 58 into contact with the work 88 and pivotal movement of the links 74 and 76 moves the rollers 78 clear of the surface 80. The entire apparatus is then resiliently supported by the spring in the bar 12 and continued application of fluid pressure to the cylinder 22 causes the electrodes to equalize on the work. In a modification a cam block mounted on the top of the bracket 10 exerts a downward force on a pin carried on the cam bar. The pin disengages from the cam on movement of the piston into the welding position. |
