Patent GB-1176893-A (GB)
Title: Coiled Filament Forming Apparatus
IPC: H01K3/04
Filed: 1968-02-06
Abstract: 1,176,893. Coiling filaments. GENERAL ELECTRIC CO. 6 Feb., 1968 [6 March, 1967], No. 5936/68. Heading B3E. A filament coiling apparatus of the type comprising a mandrel and a coiling spindle having a guide opening for the filament wire to be coiled around the mandrel, is characterized by the combination therewith of a wire-feeding mechanism comprising a support for rotatably mounting a spool of filament wire, retention means between the spool and the spindle adapted to frictionally hold the wire drawn from the spool, feed jaws between the retention means and the coiling spindle, adapted to grip the end of the wire projecting forwardly from the retention means, the feed jaws being reciprocable toward and away from the coiling spindle to draw a length of wire from the spool and insert the leading end thereof into the guide opening of the spindle, wire cutter mechanism between the retention means and the coiling spindle and actuating means for the cutter and for reciprocating the feed jaws. Operation.-Wire 7 is drawn from the spool 9 by feed jaws 43, Fig. 10, and is moved towards the coiling head A. The retention means comprises a pair of spring-loaded jaws 100, 101 through which the wire passes before reaching the feed jaws. The coiling head comprises a rotatable spindle having a central hole to receive the end of a coiling mandrel and an offset hole through which the leading end of the wire is passed into a pair of jaws which clamp the wire against the mandrel. The cutters 133, 134 sever the wire immediately downstream of the retention means. While the cut length of wire is being coiled around the mandrel, the feed jaws are drawing a fresh length of wire towards the coiling head. Construction and drive of coiling head.-The coiling spindle 12 rotates in roller bearings in a bracket 16 fastened via a block 17 to the machine bedplate 5. A gear-wheel 19 formed on the spindle meshes with a gear 18 secured to one end of a shaft 21 supported in the block 17. A gear 22 on the other end of the shaft is driven through gear train 23, 24, 25, pinion 28 and a mutilated gear 27, which rotates continuously, being driven by a worm and wheel 31, 29 and an electric motor. Cooperating arcuate segments (34, 37), Fig. 7 (not shown), lock the spindle 26 when the pinion 28 is disengaged from the teeth of the gear 27. Wire feed mechanism.-The wire 7 passes under a guide pulley 54 and through a V-notch in a lip 55 at the end of a fixed jaw 50 secured to the block 17. The wire is pressed into the notch by a spring finger 51, this assembly forming the wire retention means. The feed jaws comprise a first pair of jaws 57 and 58, of which the jaw 57 is fixed to a main slide 59, and the jaw 58 is pivotally mounted on the main slide by a pin 69. A spring 70 biases the jaw to the closed position and it is opened by a cam track engaging a roller 73 mounted on an extension of the jaw arm. The main slide is reciprocated along a dove-tail guide 60 by a connecting rod 89 actuated by a cam (94), Fig. 6 (not shown), mounted on a cam-shaft 95. The cam 74 which controls the opening of the jaw 58 is a straight-edged plate the length of which is co-extensive with the travel of the main slide 59 and which is moved transversely of the slide by a bell-crank lever actuated by a disc cam 80 mounted on a top cam-shaft 82 extending the length of the machine and gear driven from a lower cam-shaft 30. The feed jaws also comprise a second pair of jaws 100, 101 on the ends of arms 102, 103. Each of the arms is pivotally mounted on a sub-slide 104, which also slides on the guide 60, there being an aperture through the main slide 59 to expose the guide. The jaws are biased by a spring 109 to the closed position and have inter-engaging gear segments 107, so that when the jaws are opened they move symmetrically away from the wire. The arm 103 carries a roller 115 which is engaged by a cam 117 comprising a straight bar co-extensive in length with the travel of the roller 115 and moved transversely of the path of travel of the roller by a bellcrank lever actuated by a cam 123 secured to the top cam-shaft 82. The jaws 100, 101, at the beginning of a feed cycle are adjacent the wire retention jaws 50, 51. The jaws 57, 58 grip the wire and feed the leading end into a bell mouth at the rear of the offset hole 14 in the coiling spindle. The jaws 57 and 58 enter a recess 88 leading to the bell mouth. During this travel of the jaws 57, 58, the sub-slide 104 is pushed along by the main slide 59, the jaws 100, 101 also being closed on the wire. The jaws 57, 58 open after they have entered the recess 88 and the feed of the wire is taken over by the jaws 100, 101, the sub-slide 104 moving within the aperture in the main slide 59 and being driven by a connecting rod 125 actuated by a cam 130 mounted on the cam-shaft 95. The jaws 100, 101 push the leading end of the wire through the coiling spindle and between the open jaws 185, 186 so that the length of wire projecting beyond the jaws is equal to the length of the straight limb required at one end of the coil. Cutter mechanism.-The cutters 133, 134 are secured respectively to a coaxial shaft 137 and a sleeve 138 and are held in face-to-face engagement by a spring 141. The sleeve is journalled in a support bracket 140 and carries an arm 150 which is connected by a link 147 to a lever 146. The shaft 137 is connected by a pin 143 to a thrust sleeve 145, the thrust sleeve carrying an arm 151 which is connected by a link 148 to the lever 146. The lever 146 is connected by a bell-crank lever 157 to an actuating rod 161 which is moved by a cam 167 mounted on the cam-shaft 95. The feed cams are arranged so that the feed of the wire is momentarily halted while the cutters operate. Construction of mandrel mechanism.-The coiling mandrel 10 is mounted in a non- rotatable reciprocable slide 182 which is movable axially in a sleeve 183, the sleeve itself being reciprocable axially in a housing 184 secured to the bedplate 5. Pivotally mounted on a bracket attached to the sleeve 183 are a pair of clamping jaws 185, 186, the jaw 185 being directly mounted on an arm 187 and having a guide opening 194 through which the mandrel 10 passes as the slide 182 moves towards the coiling spindle. The jaw also has a lip 192 in which is a V-notch, the bottom of the notch being aligned with the hole 14 in coiling spindle. The wire is clamped in the notch by the flat surface of the jaw 186 which is mounted on the arm 188, the two arms 187 and 188 being mounted on a common pivot 189. The arm 187 is moved to its clamping position by a cam surface 214 formed on the slide 182 which acts against a roller 205 carried by the arm. A second cam surface 215 formed on the opposite side of the slide operates an arm 196 pivotally mounted on the arm 188. A spring 198 transmits the closing movement of the arm 196 to the jaw and the opening movement is transmitted as the arm 196 engages a nut 200 on a stud 201 screwed into the arm 188 and passing through a clearance hole in the arm 196. The jaws are opened by a spring 209 when the slide 182 moves rearwards relative to the sleeve 183. The sleeve 183 is reciprocated by a face cam 224 which oscillates a cam follower lever 216 the upper end of which is connected by a pair of short links 220 to lugs on the sleeve. A spring 226 biases the sleeve towards the coiling spindle and holds the roller 222 against the cam 224. A screw 225 limits the movement of the sleeve relative to the housing. The slide 182 is reciprocated, in part, by a similar cam 234 and lever 229, the upper end of the lever being connected to the slide by a link 231. The slide 182 is biased towards the coiling spindle by a spring 235, the movement being limited by a screw 238 mounted in one arm of a U- shaped bracket 239, pivotally mounted at the upper end of the arm 229. The other arm of the bracket has a bore in which slides a pin 240 which is pivotally connected to the upper end of the lever 216. The shape and timing of the cams 224 and 234 is such that the follower roller 232 is held away from the cam 234 during the coiling operation and the jaws 185, 186 and the mandrel 10 move in unison under the control of the cam 224. At the end of the coiling operation the jaws 185, 186 and the mandrel 10 retract together to draw through the hole 14 the remaining length of wire which forms the other straight limb required on the filament. The completed filament is removed from the machine by a transfer arm 241. So that the arm 241 can always be at the middle of the length of the filament, the bed plate 5 is mounted in guides 243 and is adjustable parallel to the coiling spindle axis by a screw 244.