GB1056521A - Manufacture of capacitors - Google Patents

Abstract

1,056,521. Making capacitors, bending, shearing, welding by pressure. ILLINOIS TOOL WORKS Inc. Jan. 1, 1964, No. 90/64. Headings B3A, B3E, B3R and B3W. [Also in Divisions G and H1] Capacitor units are wound from staggered e.g. aluminium electrode foils and thermoplastic dielectric films overlapping the ends thereof, and are passed along a process line wherein parallel continuous wires are attached to the ends of successive units by thermally deforming the ends to retain the wires in physical and electrical contact with the respective electrodes, and crimping and shearing the wires intermediate of the units to form discrete capacitors having attached connecting wires, which are thereafter tested and sorted. Wires 72, 74 of copper or steelcored copper are unwound from spools, e.g. 18 (Fig. 1B), straightened at 24, and spacedly presented at assembly station 22 by intermittent lateral traversing movements, effected by oscillating carriage 86, slidable on horizontal bars by pneumatic cylinder 96, and carrying locating horizontal and vertical wire vices adaptable to engage or disengage the wires by pneumatic cylinders. 102 and 92, 94 (Figs. 3, 4, 4A, 4B, 5, 6, 7, not shown); the cylinders being intermittently charged to grip the wires and oscillate the carriage. Hopper 28 contains pre-wound capacitor units comprising staggered aluminium electrode foils interwound with overlapping thermoplastic dielectric foils, each with an electrostatic shield 34 adjacent to one end and serving as an orientation band, detectable by device 30 which orients the units for impulsion by vibrator 38 down shoot 36 with the bands at the leading ends. Escapement 40 releases the units successively to assembly station 22 at timed intervals synchronized with movements of wires 32, 34, which are thus positioned to engage opposed ends of individual units, e.g. 32. Tongue 130a protruding longitudinally from a platform is mounted on base 132 carried by upright 80, and is associated with a wire height fixing member (Figs. 4A, 4B, not shown) and the tongue height is adjustable relatively to the base to support successive capacitor units, while a carriage cover member 138, carries a bifurcated spring 140 reorienting misaligned capacitor units between the spaced wires at the assembly station 22. The wires are then heated electrically in lead applying means 42. Two pairs of movable grooved copper jaws project through an apertured table, and overhead support member 144 carries a dependent flexible spring 146 orienting the capacitor units, and the jaws arc mounted on pivoted blades (Figs. 9, 10, not shown) insulated from each other and spring-biased together to be opened by a pneumatic cylinder operating through roller cams so as to admit successive capacitor units and their associated wires; after which the pairs of jaws close on the wires at each side from intervening capacitor unit, aa4 a switch (not shown) is closed to pass short duration heating currents through the respective wire intercepts, which are then forced by the spring action of the jaws into the capacitor unit end (Fig. 8, not shown), the overlapping foils being melted and subsequently hardening to retain the wires. The ends are tamped by means 44, 44a comprising heads of temperature resistant insulating material (Fig. 1F, not shown) pneumatically impelled to compress the wires into the unit ends simultaneously with the wire heating. The heads may be bored to admit a metallizing spray. Wire vice 46 operated by pneumatic cylinder 194 similarly to wire vice 100 (Figs. 5, 6, 7, not shown) retains the wires and capacitor units in position during the application and subsequent operations. A ladder chain of capacitors is formed along the spaced wires, and is passed through crimping mechanism 48 (Figs. 11, 12, 13, not shown) which is extensible and retractable by a pneumatic cylinder, and comprises scissors blades operable through a toggle linkage by a further pneumatic cylinder so as to force the wires connecting adjacent capacitor units against a central mandrel. Wire guides 218 (Fig. 1A) may be inserted between lead applying means 42, wire vice 46, crimping mechanism 48, and swaging and cut-off mechanism 50 (Fig. 14, not shown) to restrain horizontal and vertical deviation. In the mechanism 50 a pneumatic cylinder 246 operates an eccentric 232 and a spring- loaded multiple lever mechanism (Fig. 14, not shown) to operate adjustable cutter blades and swaging heads to simultaneously swage and divide the wires intermediate of the capacitor units to provide complete discrete capacitor units with attached leads protruding at right angles to the axes thereof. A transfer mechanism comprises a vertically mounted oscillable arm 346 actuated by a pneumatic cylinder 360 about pivot 348 and carries at its upper end superimposed horizontal arms 364, 366 maintained vertically disposed during motion by a keyed-on sprocket 352 linked by chains to a sprocket 356 fixed to the arm and centred on the pivot. Jaws 368, 370 mounted on the ends of arms 364, 366 are opened and closed by pneumatic cylinder 372,. and are adapted to pick up successive capacitors from the mechanism 50 by the connecting wires and transfer them to a loading mechanism 54. Wipers are provided (Fig. 2a, not shown) on the upper jaw 368 of the transfer mechanism, which are connected through switch 373 operated by arm 358 to set 70 testing each capacitor in turn for short-circuit. The presence of a faulty capacitor operates controller 371 for pneumatic cylinder 372, which opens the jaws and rejects the capacitor prior to its reaching the loading mechanism 54. In the latter, plural base bars 378, slidable in a track perpendicular to the motion of the transfer mechanism, have bevelled ends abutting longitudinally to leave a V-notch 382 therebetween. Pressure adhesive tape is fed from roll 384 over roller 392, and pressure foot 396, and the roll is traversed oppositely to the direction of bar feed by rack-and-pinion 398, 400, so that the leads of successive transferred capacitors are attached to the bars by the tape, leaving their bodies protruding. A cutter blade 402 divides the tape in the V-notch between successive bars, which are removed for dipping the bodies in epoxy resins or other coating, and after curing the tape is stripped from the bars to release the capacitors. The several pneumatic cylinders are pressurized in sequence to synchronize the successive steps of the process. The loading mechanism may be of modified form (Fig. 1C, not shown) wherein successive capacitors are picked up by magnets or spring-loaded jaws engaging the leads, mounted on an endless chain passing through processes for end metallizing, infra-red drying, dipping in resin, curing, and marking.