GB390237A - Improvements in and relating to friction clutches - Google Patents

Abstract

390,237. Friction and claw clutches. THOMSON, B., Combe Close, Woldingham, Surrey. Nov. 6, 1931, No. 30760. [Class 80 (ii).] In positive clutches of the type adapted. to be synchronized prior to coupling by engagement of a friction clutch while transmission of power to the driving-shaft is interrupted, the friction clutch is of the coil type. As applied to clutches for variable-speed gearing as described in Specification 332,302, [Class 80 (ii), Gearing, Variable-speed &c.], or with reference to Figs. 11 and 12 of Specification 339,694, [Class 80 (ii), Gearing, Variable-speed &c.], the driving clutch member 1 is slidable on the splined shaft 2 to bring internal teeth 4 into engagement with teeth 35 on a loose gear wheel 34, and has external cylindrical and conical surfaces 6, 5 to coact with the friction member 9 carried by the apertured intermediate or baulking member 7, which is normally held by a spring 25 against a stop collar 26. The member 9 may be cylindrical or conical helix or, as shown in Fig. 2, is formed by saw-cuts as a stepped coil with solid end rings 21, 24, the ring 21 being coned at 21a to coact with the surface 5 and the ring 24 pinned at 10 to the member 7, so that initial grip is obtained between the surfaces 5, 21a on axial movement of the member 1, and causes contraction of the intermediate coils 22, 23 on the surface 6. The coil may, however, act by expansion. If supplementary grip is required also for decelerating the wheel 34 into synchronism, the members 1, 9 may be coned at both ends and the coil so connected to the flange 8 of the member 7 by radial lugs with lost motion that it is tightened by torque in either direction. The two baulking-teeth 33, coacting with the apertures 30 in the part 7 by bevelled faces 31, 32, Fig. 5, are preferably distinct from the driving teeth 35, which may be formed on their periphery, as shown. In order to avoid difficulty in meshing the teeth 4, 35 if the friction clutch should " stick," the parts 33a of the teeth 33 ate cut away to allow some rotational freedom after passage of the member 7 thereover. This " reverse flanking " of the teeth 33 is equally applicable when they are spatially separated from the teeth 35 and when they act also as driving teeth.