Patent GB-491967-A (GB)
Title: Improvements in or relating to friction clutches
IPC: F16D13/75
Filed: 1937-02-12
Abstract: 491,967. Friction clutches. OLIVER, A. V. Feb. 12, 1937, Nos. 4176/37 and 1384/38. [Class 80 (ii)] The radial disengaging levers 8 of a plate clutch are actuated by the pedal - operated control collar 11 through the intermediary of a central thrust member comprising two parts which screw one on to the other, so as automatically to reduce the effective length of the member, as wear of the clutch plates occurs. As shown in Fig. 1, the thrust member comprises a plate 14 which engages the levers 8 and which is threaded on a sleeve 13, which latter carries a freely-rotatable but axially-located located member 15 adapted to be engaged by the collar 11. Studs (not shown) secured to the clutch cover 10 engage slotted lugs on the members 14 and 15 so as to prevent rotation of the latter relative to the cover 10. A coil spring 20, forming a ratchet, encircles the sleeve 13 and has one end secured to a loose plate 21 through apertures 22 of which pass pins 24 secured to the cover 10 and carrying adjustable cones 23. As the clutch plates wear and, with the clutch engaged, the sleeve 13 approaches nearer to the collar 11, the cones 23 co-operate with the apertures 22 to produce a partial rotation of the plate 21 relative to the cover 10, which rotation is, through the ratchet spring 20, imparted to the sleeve 13. The latter thus screws in the plate 14 so as to move the member 15 nearer to the plate 14. On moving the collar 11 to disengage the clutch, the plate 21 is returned to its original position, without affecting the sleeve 13, by a spring or by the action of cones 26, Fig. 4, which are secured to the cover 10 and which co-operate with other apertures 22a in the plate 21. In the form shown in Fig. 5, the part 14, engaging the levers 8, is integral with the sleeve 13 and the member 15, engageable by the collar 11, is screwed on the sleeve. A sleeve 30, having a flange 30b normally held against the inside of the cover 10 by a spring 31, has internal teeth 30a with which teeth 14a on the part 14 constantly engage and with which teeth 15a on the member 15 normally engage. A spiral spring 32 has one end secured to the member 15 and the other secured to a loose member 33 having teeth in constant engagement with the teeth 30a. As the clutch plates wear and, with the clutch engaged, the sleeve 13 approaches nearer to the collar 11, the teeth 15a pass out of engagement with the teeth 30a. The spring 32 now acts to turn the member 15 on the sleeve 13, thus moving the member 15 towards the part 14, until the teeth 15a again engage the teeth 30a, the spring 32 causing the spring 31 to yield slightly, if necessary, to permit such engagement. As the collar 11 is moved to disengage the clutch, the parts 13, 14, 15 first slide axially in the sleeve 30 until a shoulder 15b on the member 15 abuts against the end of the sleeve 30, whereupon the latter also moves against the action of the spring 31. Alternatively, the member 15 may be without teeth but have a radial flange maintained by the action of the spring 32 against the end of the sleeve 30, the strength of the spring 31 being increased so that it will not vield under the action of the spring 32. Or the sleeve 30 may be integral with the cover 10, the member 15 being toothed but having no shoulder to abut against the sleeve 30, and the teeth 15a and 30a having bevelled ends to facilitate engagement. Specifications 459,556 and 484,816 are referred to.