Patent GB-494419-A (GB)
Title: Improvements in or relating to the soldering or brazing of wires or other connecting devices
IPC: B23K3/06
Filed: 1937-04-21
Abstract: 494,419. Soldering and brazing. NEW PROCESS WELDERS, Ltd., and TURVEY W. L. April 21, 1937, Nos. 11437 /37 and 236 /38. [Class 83 (iv)] A soldering or brazing apparatus, particularly for joining parts of high conductivity, such as electric conductors, by high melting point solders, comprises means for bringing one or more electrodes and a, supply of solder &c. into contact with the work and means for automatically withdrawing the electrode or electrodes and / or the solder &c. when a suitable amount of solder &c. has been fused. In a hand tool, Figs. 1 and 1A, two electrodes E<1>, E<2> are carried by arms 1, 2 connected by insulated links 3, 3<1>, 34 to the frame 23 so that they may be swung backwards and forwards to move the electrodes relatively to a pad Ex on which the work is placed. The arms are provided with recesses 28 containing springs 25 engaging the ends 27 of links 41 which are pivoted at 191 to the frame. The solder d which is carried in wire, ribbon or strip form by a spool 10, passes through a lever 17 and through a fixed block 132 and a movable block 13 each provided with a spring-pressed ball so as to permit relative movement between the blocks and the wire in one direction only. The block 13 lies between a strong spring 15 and a weaker restoring spring 14. The lever 17 is pivoted at 18 on the links 4<1> and engages the spring 15 at one end and carries a lever 20 at the other end. When the trigger 8 is depressed it pushes back the lever 20 so as to move the lever 17 on its pivot 18, thus pushing forward the upper end and thus moving the block 13 and wire forward until the wire is arrested by contact with the work. The lever 17 now swings about its upper end forcing the pivot 18 backwards and thus moving the links 4<1> forward and so through the springs 25 and arms 1, 2 bringing the electrodes into contact with the work. When the springs 25 are fully compressed the lever 17 swings about pivot 18 and compresses the spring 15 so that as the wire is fused it is automatically fed forward. A stop 13<1> on the block 13 eventually depresses a latch 22 which through a link 21 swings the lever 20 clear of the face 30 of the trigger and thus releases the lever 17. Thereupon springs 7 return the arms 1, 2 and the springs 14, 15 expand and return the block 13 and lever 17 to initial position. The wire is thereby withdrawn slightly until the clutch in the block 13<2> is engaged which prevents further withdrawal of the wire. When the trigger is released it is returned by a spring 9 and the lever 20, link 21 and latch 22 by the spring 31. The movement of the block 13 may be limited by an adjustable stop to control the amount of solder used for each joint. In Fig. 2, in which the wire d forms one electrode, the other electrode 53 is annular and is carried by a member 52 mounted on an insulating sleeve 51 which is movable relatively to a handle 50. The handle carries leaf springs 36 which are provided with pins 38 engaging holes in a member 35 extending from a block 33 which is separated by a spring 34 from a block 55 to which the other current lead is attached. The blocks 33, 55 are provided with spring-pressed split collets for permitting relative movement between the blocks and wire in one direction only. The electrode 53 is pressed against the work by the handle 50, which then causes the block 33 and wire to move forwards relatively to members 51, 52, to compress the spring 34 until the wire engages the work. As the wire melts it is fed forwards under the action of the spring 34 until the bent ends of the springs 36 engage the end of the sleeve 51, which removes the pins 38 and thus allows the member 35 to be returned by the spring 34. The wire is slightly withdrawn whereupon it is held by the collet in member 55. On removing the tool from the work the parts 50, 51 resume their initial positions under the action of spring 40. Reducing gas may be supplied to the electrode 53 through a pilot jet 49 and main jet 39. Current may be supplied from a transformer through a normally open switch closed by pressure of the trigger 8 or by movement of the electrode 53 or the circuit may he automatically completed when the solder or electrode makes contact with the work with sufficient pressure. Variations in the magnitude of the current may be reduced by a barretter valve in the transformer primary or by a constant current transformer. The current may be cut off through a timing- device such as a clockwork or thermionic valve timer, which may also actuate the latch 22. Two electrodes may be used either both on the same side or on opposite sides of the work, or in contact with each other so that the work is heated by thermal conduction. A single electrode may be used. In this case the work may form the other electrode, and may be connected to the second terminal by clamps or fingers or through a metal member providing a mechanical reaction to the thrust of the electrode. The solder may be connected to this terminal. Heating may also be effected by a member 42, Fig. 3, itself heated by a resistance 41 in contact or very close to the member 42. An electrode may also consist of a face piece 44, Fig. 5, of high resistance metal connected by one or more prismatic or cylindrical or laminary members 45 to a block 46 to which the current is connected. In the form in which current is to pass through the electrode only the face piece may be connected by two or more of the members 45 to two separate blocks 46 to which the supply terminals are connected. The electrodes may be of high resistance metal such as cadmium, chromium, gold, iridium, manganese, molybdenum, nickel, osmium, palladium, platinum rhodium, ruthenium, silicon, tantalum, tungsten, vanadium or selenium and may contain a proportion of a less resistive metal. An iridio-platinum alloy may be used. According to the first Provisional Specification the electrode may also be made of carbon.