Patent GB-471259-A (GB)
Title: Improvements in or relating to machines for forming and fixing electrical contacts
IPC: H01H11/04
Filed: 1936-03-17
Abstract: 471,259. Making electric contact springs. ERICSSON TELEPHONES, Ltd., WILMAN, C. W., and TRAPP, C. C. March 17, 1936, No. 7975. [Classes 83 (ii) and 83 (iv)] Riveting; shearing.-A machine for applying electric contacts to contact springs for use on relays, switches, or like devices comprises means for cutting a short length from a continuous wire, for inserting the length into a hole in a spring and for forming it into the desired contact shape. Springs 43 are carried on an annular turntable 5 on which they are spaced at intervals of 30‹. Two sets each of four tools 3a ... 3d, Fig. 1, are carried, spaced at 45‹, in a turret 1, a pair of diametrically opposite springs being acted on simultaneously by the respective sets of tools, the turret being moved to bring the successive tools in turn over a stationary spring. The tools are actuated by a rocker 18a controlled by cams 16a. Contact wire 58 is fed upwardly through channels 7, 8 in shearing plates 56, 10 against gauge plates 9, the part in the channel 8 being sheared by relative rotation of the plates 56, 10 on movement of the turret through 45‹. Tapered stops 11 actuated by a cam 16b and rockers 18b on a bridge 67 swing the springs about pins 6 to bring holes 46, 47 which are to receive the contact wire respectively beneath the tools at the two stations. Alternatively, the turntable and turret may be mounted eccentrically so that the holes are brought beneath the respective tools without a swinging movement. Pointed tools descend, after the members 11 are raised, to enter the hole 46 or 47. In a modification, the holes are punched from an unperforated blank at this position. A clamp 12 is lowered to grip the spring by two shoes carried on a spring plate, the tools 3a are raised, and the turret moved through 45‹ to bring tools 3b over the springs, and the severed lengths of contact wire in the channels 8 beneath the spring and the tools. The tool 3b which may comprise an outer portion 59, Fig. 11, surrounding the contact hole, and an inner spring-pressed plunger 60 descends to steady the spring, and rods 13, actuated by cams 16d, rockers 18d, and plungers 66, rise to push the wire into the hole, the wire rising against the plunger 60 until a stop 61 thereon contacts the end of the member 59. The rods 13, which are preferably pointed, produce a slight spreading of the lower end of the wire to secure it in the hole. In the successive positions of the turret the end of the wire is riveted over by tools 3c, 3d in successive stages a, b, Fig. 14, the clamps then being raised and a further pair of springs brought into position by movement of the turntable. The turret, turntable, and wire - feeding mechanism are operated respectively by onerevolution clutches 25, 26, 31, Fig. 5, the engagement of the clutches being controlled by cams 16e, 16f, 16g, rocker arms 18e, Fig. 7, and pins 62 engaging cam surfaces on the clutch parts. The turret is actuated by Geneva mechanism 21, 23, the turntable by mechanism 22, 24, and the wire feed by cams 29 on shafts 30. The cams 29 produce upward and downward movement of a carriage 27 and inward and outward movement of gripping-jaws, the wires being gripped on the upward movement of the carriage, but released on the downward movement. The movement of the carriage is limited by the plungers 66 engaging stops on a plate 32, this engagement also causing the end of the wire to be withdrawn slightly into the lower shearing plate to remove any burr. Contact wire fed from drums 36 passes through tubes 73 having a restricted portion at their exit ends to prevent retrograde movement, the effect being assisted by a pair of friction plates or a pawl 53, Fig.. 8. The machine may be modified for securing only one contact member to each spring, and contacts may be formed on both sides of a spring. Automatic loading or unloading arrangements may be provided.