Improvements in or relating to methods of and apparatus for welding small tip elements to base elements such as pen nibs and like articles

摘要

493,529. Welding tips to pen nibs, bearing pivots, and phonograph needles. PFANSTIEHL CHEMICAL CO. April 8, 1937, No. 10035. Addition to 466,352. [Classes 83 (ii) and 83 (iv)] Relates to the method of welding small metallic tip elements to metallic base elements such as pen nibs, meter bearing pivots and phonograph needles, described in the parent Specification and consists in an improvement or modification of the method including heating the elements by passing an electric current therethrough and automatically stopping the current upon movement of one element a predetermined distance towards the other. Spring-operated copper jaws 17, 18 hold the nib and are carried by a support 14 pivoted at 11 in ball bearings and balanced by a slidable counterweight 16. A current controlling means comprises a solenoid 136 on a mounting 37, the slidable coil portion 137 of which carries contact strips and a stop 42 which is brought into the path of a stop 101 carried by the guide 15 for the counterweight and thus moving with the pivoted nib-holder. A support 20 adapted to be adjustably positioned by screws 26 is provided for the tip element 22 and a number of small holes in the holder admit an inert gas such as hydrogen during the welding operation. The stop 101 is slidable in a sleeve 32 and frictionally held by a spring, it is pre-set by first striking an abutment 35, when the jaws are raised to admit a tip to the holder, and then by coming into contact with the stop 36 carried by the slidable part of the solenoid. When the solenoid is operated the abutment 42 connected to the switch 43, Fig. 8, is brought into line with the stop 101 and as this moves upwardly with melting of the nib and tip during welding, the switch 43 is opened upon fall of the nib a predetermined distance and the welding circuit opened. Current is supplied at 110 volts A.C. through lines 70, Fig. 8, to the primary of a transformer 74, the secondary 75 of which supplies the welding current to the nib &c. A cut-out switch 88 is operated by a solenoid 87 energized from a battery 83, the current from which is controlled by the switch 43 and a further switch 85 controlled by a cam 60 driven by friction means from a motor 72. A further switch 82 controlling the current to the solenoid 136 is operated by the cam 60, the switches 82, 85 being closed in succession to operate, first, the solenoid 136 and then the welding circuit switch 88. The nib will drop from 0À004 to 0À015 inch before the switch 88 is opened by the relay and stop switch 43.