GB878010A - Improvements in or relating to apparatus for driving webs - Google Patents

Abstract

878,010. Driving record tapes. ELECTRIC & MUSICAL INDUSTRIES Ltd. Feb. 6, 1958 [Feb. 12, 1957; May 14, 1957], Nos. 3723/58 and 15223/57. Divided out of 878,008. Class 40 (2). [Also in Groups XVI and XXIV] In apparatus for driving a record tape such as film or magnetizable tape, in either direction through an operating zone which may comprise an optical or magnetic transducer, wherein the tape passes around a driving capstan of the vacuum type on a shaft 3, Fig. 2 (Prov.) 15223/57, and two take-up spools 9, 10, either one of which is effective according to the direction of rotation, the said take-up spools are driven by the capstan shaft 3, through a toothed belt 15, or through a linkwork coupling, Fig. 2 (Comp.), and the drive to each spool includes a one-way clutch 11, 12, effective in the take-up direction only, and a friction slipcoupling. The slip and one-way coupling comprises a driving toothed wheel 17, Fig. 3 (Prov.) 15223/57, driven by the belt 15, and clamped between discs 20, 23, together with interposed discs 21, 22, by an adjustable spring 25, the plate 20 carrying a pawl 11a engaging a ratchet wheel 11 fast on the spool shaft 7. A jamming ball-ratchet clutch may replace the positive pawl clutch. A magnetic or other brake may be associated with each shaft 7, 8 and momentarily actuated during the reversal period to prevent spool overrun or partiallyactuated during the uncoiling operation to maintain tension in the unwinding run and to prevent any spool rotational oscillation. During reversal the capstan roller vacuum may be released to permit relative movement between the said roller and the tape and allow the tape winding spool to increase in speed, thus maintaining the tape taut. The alternative linkwork coupling, Fig. 2 (Comp.), comprises a driving crank 28 on a shaft geared to the capstan shaft, driven cranks 30, 31 associated with take-up shafts, and a three-armed connecting rod 29. In this form the one-way and slip coupling may be as described in Specification 878,009. The capstan shaft 3 is driven by a reversible electric motor or by a non-reversible motor through worm and reversible friction gearing, Fig. 1 (Comp.) (not shown), which includes further braking means and forms the subject-matter of Specification 878,008.