Patent GB-1141075-A (GB)
Title: Improvements relating to assembling electrical components to a circuit board
IPC: H01L21/00
Filed: 1966-06-23
Abstract: 1,141,075. Welding by pressure. TEXAS INSTRUMENTS Inc. 23 June, 1966 [24 June, 1965], No. 28058/66. Heading B3R. A jig for holding electrical components for connection to a circuit-board comprises a grid having an array of openings, a plurality of inserts for fitting in the openings, the inserts being capable of receiving the components, and means for securing the grid with inserts therein to a circuit-board. A jig 11, Fig. 2, for miniature semi-conductor networks comprises a grid 21 and a backing plate 23 hinged together at 25 and clamped by a clip 27. The grid has rectangular openings 31 with bevelled surfaces to receive mating bevelled surfaces on inserts 33, Fig. 8. Each insert has a locating tab whicK fits in a recess in the grid and has a bridge member 37 which spans the opening 31 to leave an aperture 38 on each side of the bridge. A nest on the underside of each bridge member receives a network having flat leads 45 extending therefrom. With the grid 21 and inserts 33 inverted from the position shown in Fig. 2, the backing plate 23 being hinged back, a semiconductor network may be deposited in each nest with the leads 45 projecting from each side of the bridge 37. A printed circuit-board 51 is laid over the grid with printed circuit conductors and leads 45 in contact and the backing plate is clamped by clip 27. The assembly is then returned to the position of Fig. 2 and placed on a table 19, Fig. 9, movable over a platform under the heads 15, 17, Fig. 8, of a welder. Each head includes a pair of electrodes 50 connected to a pulse power source. When an opening containing an insert arrives under the welding heads upon movement of the table the projecting part 47 of the bridge 37 engages a lever 55 of a sensing switch SS1 between the heads the actuation of which causes the heads to drop through the apertures 38 on to the leads 45 to weld the leads to the printed circuit. The table 19 is driven along ways 61, Fig. 9, in direction Y by a lead screw 63 and the ways 61 and screw 63 are mounted on a pair of carriages 65 (only one shown) which are driven along ways 67 in direction X by a lead screw 69. Each lead screw has a detent and switch device 73, 75 respectively, the device 75 comprising a disc 77 on the screw 69 and having notches 79 into which a spring-loaded roller 81 is urged to actuate a switch DSX. With the table initially in one corner of the platform the table is traversed on the Y-axis until a sensing switch under the welding heads is contacted by a tab 24 on the jig to stop the table. The table is then traversed along the X- axis until a grid insert tab 47 contacts the switch SS1 on the welding heads. The X-axis motor operating under control of the switch DSX then stops the table at the spacing of the leads 45 and welds are effected at each position. After a given number of welds determined by a cycle counter the X-axis motor resumes movement along the X-axis and when all the leads in a row have been welded the table is caused to move to present a new row for welding. The table movement along the X- and Y-axes may be controlled by punched tape and photo-cell devices or modified component holding devices may be used wherein the bridge portion carries raised tabs corresponding to the positions of the leads 45 and these tabs are detected by a light source and photo-electric cell device.