928,272. Capacitors. BRITISH INSULATED CALLENDER'S CABLES Ltd. Nov. 3, 1961 [Aug. 5, 1960], No. 27278/60. Class 37. [Also in Groups XVI and XXIV] A capacitor winding machine comprises a two-part mandrel as described in Specification 928,273 and means for moving the mandrel into a first position in which it is wound and into a second position in which the wound capacitor is released, the rotation of the mandrel being stopped in a predetermined angular position, between the first and second position, where the composite strip is clamped and severed. The capacitor may be of the paper foil or the metallised paper type. The machine (Fig. 1) comprises spindles 5-10 carrying paper strip rolls 11-16 and spindles 17, 18 carrying metal foil rolls. Paper and metal foil strips are guided between " nip " rollers 22, 23 (foil F1 passing over a length measuring rollers 27) to form a composite strip which is then wound on a two-part mandrel (Fig. 5) 30 carried on a pivoted frame 29. The mandrel is driven from a gear-box 33 through a chain 34 and sprocket 35 rotating freely on spindle 36 about which frame 29 pivots. The paper and foil strips are each maintained at constant tension by a separate brake (Fig. 3) consisting of a roller 37 carried on an arm 38 (see also Fig. 1) bearing on pad 16. The arm 38 is attached to a spindle 39 to which spring arms 40, 41 carrying braking pads (Fig. 4, not shown) are attached, the braking pads bearing against opposite surfaces of a disc 43 attached to the paper carrying spindle 10. The pressure of the pads on disc 43 is adjustable by knob 45. Feeders 50, 51 feed terminal strips between " nip " rollers 22, 23 at set positions as described in Specification 928,271. Operation.-The mandrel is driven by a shaft 96 (Fig. 7), when magnetic clutch 95 is energized, via sprockets 97, 35 (Fig. 1). Shaft 96 carries three pairs of detent discs 121, 122; 123, 124; 125, 126 associated with the terminal tab feed mechanism (see Specification 928,271) and a further detent disc 127 associated with the discharge of the completed capacitor. Shaft 96 is driven at a lower speed for insertion of the terminal tabs when magnetic clutch 103 instead of 95 is energized. Detents associated with the detent discs are operated by solenoids under control of a length measuring device G (Fig. 1) driven by a roller 27 bearing against foil strip F1. Roller 27 is coupled to a timing cam-shaft (Figs. 8, 9, not shown) is rotated once when sufficient foil F has passed through the " nip " rollers 22, 23. One of the tracks of a two-track cam on the timing shaft controls a two-way switch for energizing the detent solenoids and the other of which controls a change-over switch to energize the "slow-speed" clutch 103. Energization of solenoids controlling the position of the various detents is pre-set by the rotation of a selector cam-shaft 152 (Fig. 7) cams 146-150 on which operate switches S6-S10 associated with the solenoids in the correct sequence (Fig. 10, not shown). Shaft 152 can take up any one of four positions at 90 degrees to one another. Discharge cycle.-(1) Clamping of the metal foils is effected by two pairs of rollers 210-213 (Fig. 12) driven through linkages 204-208 by a cam on a shaft 74 immediately the latter starts rotating (see below). A further cam on shaft 74 operates blades 215-218 to cut the foils. (2) Shaft 74 is connected to a shaft 110 (Fig. 11) driven through linkages by the engagement of detent 195 with the disc 127 on the mandrel drive shaft 96. Shaft 74, 110 first rotate through about 20 degrees at 5 r.p.m. after which detent 195 is released from disc 127. It remains in the release position until mandrel shaft 96 has rotated for 2¢ revolutions at the slow speed (60 r.p.m. clutch 103 energized). Only paper will be wound on to the mandrel during these 2¢ revolutions as the metal foil has already been clamped. (3) When the mandrel has completed the 2¢ revolutions, detent 195 engages the second notch on disc 127 and shafts 74, 110 are again driven. Two cams 201, 201a forming a desmadronic pair on shaft 74 now co-operate with followers 72, 73 on the mandrel frame pivot 36 to rotate the mandrel frame 29 to its lower position where the mandrel axis is at 75 (Fig. 1). (4) In order to prepare for the winding of the next capacitor, as the mandrel is moved to its lower position and has stopped rotating a length of foil determined by a pawl and ratchet device 236 (Fig. 14, not shown) is fed into the nip between rollers 22, 23 by the rollers 210-213 (Fig. 12) driven through pinions 229-232 and 233, 234. The amount of time during which the pawl and ratchet can engage, and therefore the length of foil fed forward can be varied by adjusting the angle through which shaft 236b and pinion 229 rotate. The clamping pressure of rollers 210-213 is then released. (5) Gummed paper strip is fed forward (Figs. 15-17, not shown) as the mandrel is pivoted to its lower position, by shaft 36 forming the mandrel pivot. (6) The composite strip (now consisting only of paper) is clamped by clamps 271, 272 operated by a cam 270 on shaft 74. (7) The mandrel now rotates through a further 1¢ revolutions, when blades 281, 282 on the clamp cut the paper strip and the gummed paper is wound round the element. (8) Fingers 31, 32 (Fig. 5) of the mandrel are withdrawn into guide tubes 55, 54 by cams 76, 77 mounted on spindle 36 and acting on followers carried by operating arms 78, 79. Arm 78 for example moves sleeve 60 along tube 54 thus withdrawing finger 32. The capacitor is thus discharged assisted by spring blades 284. (9) The mandrel is returned to its upper position and winding of a new element starts.