Patent GB-1407110-A (GB)
Title: Wiring electrical components to circuit boards
IPC: H05K1/00
Filed: 1973-12-18
Abstract: 1407110 Interconnecting electrical components; soldering UNITED WIRING & MFG CO Inc 18 Dec 1973 [26 Dec 1972] 58533/73 Headings B3A and B3R A method of interconnecting electrical components 70 on a circuit board 10 comprises: providing rows of solder pads 42 Fig. 5 on one face 14 of the board, each coincident with one of a plurality of orthogonally arranged holes 44 extending through the board, mounting parallel guide strips 60 extending between adjacent rows of solder pads in a first direction of the orthogonal arrangement, the strips having upstanding fingers 64 aligned with the holes, inserting conductive pins 72 through the holes from the face opposite the pads, passing insulated wire 82 around selected pins and around selected fingers of the guide strips and soldering the wire to a pad at each location where the wire passes around one of the pins electrically to interconnect the components on the board. The guides 60, Fig. 3 (not shown), are of plastics material and are secured to the face 14, e.g. by adhesive. When the components 70 have been placed on the board, it is located on a table 74 under a wire feed unit 76. The table is moved by programme control or manually under the feed unit so that a continuous wire is strung to all the required locations on the board in one operation, including edge posts 90 on the table 74. Where the wire is to be cut, it is passed from a finger 64, preferably twice around a pin 72 and then around a different finger 64 causing the wire to extend diagonally between the pin and finger, e.g. at wire sections 86a, 86b, 86c. A knife holder (not shown) carrying knives 88, Fig. 5, moves downwardly to drive the knives into the areas between adjacent solder pads 42 to cut any wire extending diagonally. Alternatively a single knife may be used and moved under programme control to cut the wires. The wire secured to the pins 90 is cut by the knives and remains attached to them when the board 10 is removed from the table 74. Solder connections are formed between the wire 82, the pads 42, the holes 44 and the pins 72 by contact heating, induction heating, laser beam or micro-wave heating to vapourize the insulation and melt the solder either simultaneously or in two separate steps. Shields 94, Fig. 5, are located adjacent the pins to be soldered to afford thermal insulation for the wire adjacent a solder location. Instead of components 70, a conductive comb (100), Fig. 6 (not shown) may have its teeth (104) inserted in the holes 44. The teeth are wired similarly to the pins 72 and after soldering, the spine (102) of the comb is severed from the teeth (104) to leave a plurality of interconnected pins. The comb may also be used in conjuction with components having pins (112), Fig. 7 (not shown), to provide an effective lengthening of the pins to allow wire to be wrapped around them. The components 70 may comprise dual in-line circuit packages which, when defective, are removed by cutting the pins 72, e.g. along the chain dash line in Fig. 8, to prevent damage to the existing soldered connections. The pins of replacement circuit packages are bent to form feet 116 which are soldered to peninsular areas 50. These areas surround the holes 44 and provide sufficient thermal insulation to prevent unsoldering of existing connections on the other side of the circuit board.