Patent GB-871513-A (GB)
Title: Method and apparatus for threading lead-in wires of an electrical device into pins on a base
IPC: H01J9/30
Filed: 1957-10-29
Abstract: 871,513. Threading lead-in wires into base caps of electrical devices. SYLVANIA ELECTRIC PRODUCTS Inc. Oct. 29, 1957 [Oct. 29, 1956], No. 33751/57. Class 39(2). A method of fitting a base cap to an electrical device in which lead-in wires extending from the device are located in corresponding pins on the base consists in the steps of positioning the base against a threader with the pins in axial alignment with respective apertures in the threader, positioning the device so that the lead-in wires extend towards the corresponding apertures in the threader, and causing the device to execute relative to the base and threader an orbital motion of small radius about an axis generally parallel to the pins while effecting relative movement of the device and the threader and base to advance the lead-in wires through the threader and into the pins. The threader is separated from the lead-in wires after they have entered the pins and they are then advanced further into the pins by relative longitudinal movement of the device and the base. The lead-in wires are finally welded to the pins. A machine for carrying out the method consists of a base 2 supporting a main shaft 8 carried in end bearings 4 and central bearing 10 and driven by a belt 36 from a driving shaft 32. Each end of the shaft carries a threading head spider 14 and a lamp head spider 18 separated by a stationary cam drum 22 carrying a succession of cam surfaces for effecting the sequence of operations. Lamp tubes 1 are fed down an incline to a paddle wheel feeder 64 which deposits them in jaws on arms 94 on each lamp head spider. The tubes are rotated in the jaws by contact with a cam surface 132 until one of the lead-in wires engages a feeler wire operating two solenoids, one of which retracts the cam surface 132 and the other withdraws a cam surface from contact with a follower 108 on a pivoted jaw 72 which thereupon closes on the tube gripping it in the adjusted position. Lamp caps 7 are fed to cap holders down a slope 76 under the control of an escapement 78 actuated by a feeler arm 80 which is deflected by the lamp tube so that in the absence of a tube no cap is fed to the cap holder. The caps are held in clamps 158 which are closed at the start of the operation and opened at the end by locking mechanism 140 operated by pins 142, 143 engaging cam surfaces 144 at the start and cam surfaces 146 at the end, these cam surfaces being carried by the end members 4. For threading the lead-in wires into the pins of the cap, the tube is moved in an orbit about an axis parallel to the pins by means of a disc 302, Fig. 18, which is in frictional contact and normally co-axial with a disc 308 driven from the main shaft through gearing 40, 48 but which is displaced laterally by downward movement of the arm 94 when a roller 92 on this engages a rod 82 pivotally mounted in a bracket on the cam drum 22. The disc 308 continues to drive the disc 302 thereby producing an orbital motion of the end of the tube. At the same time, two split threading cones 148, 152 disposed between the tube and the cap gradually and successively close thereby guiding the lead-in wires into alignment with the pins. Simultaneously the cap is advanced towards the tube until the lead-in wires have passed through the pins. Further movement of the spiders then brings the caps into contact with revolving electrodes, current for which may be supplied by a condenser (not shown) which discharges immediately a lead-in wire comes into contact with one of the electrodes, whereby the lead-in wires are welded into the pins, the surplus end pieces being simultaneously removed. At the end of the operation jaw 72 is opened by engagement of the follower with a cam surface 112 and the tube complete with caps is discharged on to a table 114.