GB584109A - Improvements in method of and apparatus for welding studs, rods, bars or the like tosurfaces - Google Patents

Abstract

584,109. Welding. LINDE AIR PRODUCTS CO. March 20, 1945, No. 6936. Convention date, April 7, 1944. [Class 83 (iv)] In welding an end of a metal member, such as a stud, rod, or the like, to a metal surface, the member is positioned with its end spaced away from the surface and is enclosed by granulated mineral like welding material, a welding current is passed through the member, welding material and surface so as to fuse the material and melt opposed portions of the member and surface which are then brought into firm contact with each other to effect the weld. The stud, or the like 25, is gripped in a spring chuck 24, carried by a terminal 22 having a conductor 23 attached. The terminal is bolted to, but insulated from, the stem 20 of a plunger 18 which is contained in a casing 10. The plunger is hollow, forming a cylinder 30, 'in which is mounted a piston 31 having a rod 32 extending up through a stuffing box 33 to a handle 42. A bracket 12 is secured to the lower end of the casing and carries a gauge 11 on the lower end of which is slidably mounted a bracket 13, locked by a set-screw 14. The bracket carries a ring 15, in which is slidably mounted a tube 16 secured by a set-screw 17. In operation, the handle is pulled out compressing a spring 35 and further upward movement compresses a further spring 26 interposed between a shoulder 27 in the casing and a collar 28 on the stem 20. The fluid above the piston is forced through the internal byepass 38 in the piston and a ball valve, which is normally closed by a spring 40, to the cylinder 30. An adjusting nut 43 on the rod engages a latch 44 having a trigger 45, which is urged upwards by a spring 46 to hold the handle out, and a further latch 29 engages collar 28 to hold it in its retracted position. The granulated welding material is placed in the tube 16, surrounding the tip of the stud and trigger'45 depressed, starting the welding current through press button 51. At the same time latch 44 is tripped, releasing the handle and allowing spring 35 to act on the piston against the pressure of the fluid in cylinder 30, which is now forced through the external byepass 36 and an adjustable needle valve 37 to the upper chamber. As the piston descends, nut 43 strikes a head 48 of a trip rod 49, which trips latch 29, releasing spring 26 which plunges the stud into the molten metal of the part to which it is to be welded, and as this occurs, the operator frees trigger 45, cutting off the welding current. Steel wool may be placed in the gap between the stud and the work to start the arc ; a high-frequency voltage applied in addition to normal welding supply, or the electrode pointed to pierce the welding material. In a modification to allow of slower descent of the stud during the welding period the timing mechanism consists of a small series motor 84, driving through worm gear a release mechanism 61 through a planetary gear system 78, 79, 80, and rack 70, until at a predetermined length of travel a latch 64 is tripped and the spring- operated plunger 62 released to plunge the stud into the welding puddle. The periphery of the ring gear is engaged by a brake band 85 secured to a lever 87, urged by a spring 89 away from the switch 90 controlling the motor and welding current. The feed mechanism is reversible to allow re-setting for a new weld.