GB1314981A - Crimping-die - Google Patents

Abstract

1314981 Moulding electrical connectors BURNDY CORP 16 March 1970 12504/70 Heading B5A [Also in Divisions D1 and H2] The invention relates to a two-stage crimping die assembly for a tubular metal connector surrounded by a plastic sleeve. The metal connector, Fig. 7, is of the kind having a terminal 10 and a crimp barrel 11 that is inserted into the plastic sleeve 12, Fig. 8. The sleeve 12 projects in the form of a shroud 19 rearwardly of the barrel 11 away from the terminal 10. An insulated cable, having a bared end 18, is then inserted into the connector such that the bared end 18 is in the crimp barrel 11 and the sheath 17 of the cable is in the shroud 19. The two-stage die, described below, then crimps the connector and the sleeve on to the cable as in Fig. 9, the die being such that the plastic sleeve develops at least one ridge 50, 55 on its outer surface to prevent excessive extrusion of the plastic sleeve 12 out of the die during the compressing operation. The die, Fig. 2, has a fixed lower part composed of a barrel crimping portion 22 and a shroud crimping portion 21. The upper part of the die is mounted on a piston P and descends through a fixed housing 70, 71. It comprises a barrel crimping part 38 that is rigid with the piston P and a shroud crimping part 40, 62 that is biased downwardly by a spring 75. A pin 77 limits the lower setting of the shroud crimping part 40, 62 and an axially displaceable bar 85 limits the upper setting of the shroud crimping part 40, 62, the bar 85 being of stepped formation to permit selection as to the effective thickness of the bar. The barrel crimping parts of the die are formed with grooves 26, 28, 37, 39, Fig. 5, that co-operate to form annular channels into which the plastic sleeve 12 can flow during the crimping process and so prevent excessive extrusion of the plastic sleeve 12 from the die. Due to the spring 75, the shroud crimping portion 40, 62 is effective first but exerts very little effective pressure. Thereafter the barrel crimping part 38 is effective to crimp the connector on to the cable, the shroud crimping portion 40, 62 being then also effective by an amount determined by the setting of the bar 85. The shroud crimping surface 40 is of conical shape, Fig. 5, such that the plastic sleeve 12 will tend to be extruded into the channels 26, 28, 37, 39 rather than be extruded from the die. When the die is opened the spring 75 ejects the completed connector from the upper die.