GB756496A - Improvements in or relating to methods of and apparatus for applying electrical connectors to insulated conductors - Google Patents

Abstract

756,496. Making electrical connectors. AIRCRAFT-MARINE PRODUCTS, Inc. April 27, 1954 [April 27, 1953], No. 12157/54. Classes 83 (2) and 83 (4). Jointing by stamping.-A method of applying electrical connectors to the ends of insulating wires comprises preforming a strip of connector blanks each having a pair of upstanding ear portions adapted to be formed into a ferrule portion, positioning said connector blanks one at a time between a pair of crimping dies, stripping the insulation from the end of a wire adjacent the end connector blank of the strip, moving said wire from the insulating stripping operation into a position between the upstanding ears of the end connector blank, curling said ears about said wire strands so as to gather any laterally displaced strands and compacting the ears about the wire into a solid mass whereby all strands of the wire are enclosed within said ferrule forming portion. The machine for use with a strip 12 of connectors 14 having ferrule forming portions 16, comprises a cast frame 26 a pneumatic ram 46 guided therein and carrying a crimper 24 and an adjustable bed 62 carrying the lower crimping die 18. The strip is intermittently fed by a finger 112 cam-operated from the ram 46 and a spring- loaded drag plate 144 prevents it from sliding back away from the crimping area. The strip is guided between plates 132. Adjacent the crimper 24 and the ram is a shear blade 34 which co-operates with a shear plate 36 and a slug plate 38 on the bed 62 to sever a connector from the strip as the ram moves downwardly. The operation of this part of the machine is fully described in Specifications 665,592 and 665,593. The wire-stripping mechanism consists of a wire clamping assembly 40 which grips and pulls a wire 32 through a wire stripper assembly 42. The clamping assembly consists of a pivot block 44 attached to the ram and a clamp holder 56 having a guideway 58 in which two spring-loaded jaws 64, 66 (Fig. 6), are disposed, said holder being carried by two arms 68 pivoted on the block 44. Follower pins 57 on the holder ride in cam slots 55 in cams 70, 72 mounted on the press bed 62. The outer ends of the clamp jaws are provided with cam surfaces 63 and 65 which engage cam surfaces 71 on the cams 70, 72 to move the clamps together as they are carried downwardly with the ram. The wire-stripper assembly includes a guide block 76 mounted on the bed 62 and opposed stripper blades 78, 80 engaged by spring-loaded rocker arms 84 pivoted to the guide block and carrying rollers 88 which abut the lower corners of the ram when the ram is in its upper most position. On the downward stroke the ram passes between the rollers and moves them apart to close the blades. The stripper blades have semi-circular conical insulation cutting edges 77 and angularly disposed wire guiding surfaces 79 arranged so that those on each blade overlap those of the other blade to accurately centre the wire between the cutting edges 77 as the blades are closed and so prevent any wire strand being removed with the insulation. A metal-sensing unit operating on capacitance or magnetic flux principles may be incorporated to detect the presence of a strand in the removed insulation and to give an audible signal or stop the machine. In operation, an insulated wire is inserted between the open gripper jaws 64, 66 through the crimper cavity and between the stripper blades 78, 80 until the end of the wire abuts an adjustable micro-switch stop (not shown) which automatically starts the press cycle. The initial descent of the ram drives the rollers outwardly and the stripper blades cut through the wire insulation sheath 33. The wire clamp holder 56 is driven down by the ram and guided outwardly by the cam slots 55 the initial descent closing the gripper jaws around the wire. Thus the wire is pulled out of the stripper blades leaving the severed end portion of insulation behind. Further downward movement of the ram causes the clamp holder to centre the stripped end in the connector 14a, and to compress the ferrule portion around the bared strands to form the connection as shown in Fig. 10. As the ram rises the newly attached connector is lifted from the lower crimping die and the next connector is fed into position. The stripped portions of insulation may be blown out of the machine by an air jet. Specification 650,096 also is referred to.