GB928102A - Improvements relating to apparatus for soldering wire terminals to a printed circuitboard - Google Patents

Abstract

928,102. Soldering. FERRANTI Ltd. April 3, 1962 [April 15, 1961], No. 13661/61. Class 83 (4). An apparatus for soldering wire terminals to a printed circuit board includes a soldering iron movable along a vertical axis, means for projecting a beam of light to intercept said axis at a point, and means for moving said iron into engagement with a terminal positioned at that point and maintain it in contact for a predetermined time, after which a biasing means returns the iron to an upper position. In operation, an operator moves a printed circuit holder 40 on the machine table 2 until the light from a projector 37 falls on the terminal to be soldered, which is then positioned on the vertical axis 5a along which the iron 5 moves. The operator then lifts a weight 20 by means of a foot treadle (not shown) and a plunger 22, thus allowing the biasing means 10 to raise the iron 5, sleeve 3 and cylinder 13 to an upper position in which the piston 18 is also at its upper position in the cylinder 13. The sleeve 10, which carries the cylinder 13 on an arm 12, the iron 5 on an arm 4 and a lower retainer for the spring 10 on a band 11, is mounted on ball bearings and free to slide axially on a fixed pillar 1. The pillar 1 also carries a collar 7 on which is mounted an extension 9 for retaining the upper end of the spring 10. When the operator releases the weight 20, the piston 18 remains substantially at rest in the cylinder 13 while the entire sliding assembly descends against the action of the spring 10 until the soldering iron has descended past a strand 33 of cored solder (some of which it retains) and contacted the terminal 39 to be soldered. The piston 18 with the weight 20 continues to descend slowly in the now stationary cylinder 13 as air enters through an adjustable throttle valve 15, 16 until the piston clears a relatively large air inlet 17; the piston then descends rapidly to its initial position and since the weight 20 is no longer restraining the sliding assembly, the spring 10 abruptly withdraws the iron 5 from the soldered terminal. Solder is fed automatically through a tube 35 from a reel 34 by means of a pawl 28 which is actuated by a nut 31 carried on the sliding assembly. The apparatus may be modified by moving the iron into engagement with the terminal by means of a solenoid, the timing being determined by controlling the current supply to the solenoid. A further solenoid may be used to bias the sliding assembly upwardly.