Patent GB-328313-A (GB)
Title: Free wheel clutch mechanism for use in hoisting and other load-carrying machines
IPC: B66D1/12
Filed: 1928-12-20
Abstract: 328,313. Scott, M. D. Dec. 20, 1928. Driving - arrangements.-In hoisting, printing, calendering, and other loadcarrying machines having a main driving-motor and an auxiliary hand or power motive-device for slow-speed running, as at starting and stopping, the means for uncoupling the auxiliary device when its speed is attained or exceeded by the main motor comprises a unidirectional or bidirectional overrunning clutch of the self-tightening kind having a loose member connected to a fast driving-member by links which, due to lag or inertia of the loose member, assume an oblique position under load and slide one loose member into engagement with a driven member, the fast member being permanently coupled or geared to the auxiliary motive-device. The clutch may be mounted on the shaft driven by the main or auxiliary motor &c. or on a layshaft chain-geared &c. to the main shaft. When the clutch is on the auxiliary shaft, the driven member, coupled to the main shaft, is formed on a sleeve on which the loose member can slide. The mechanism is applicable also for starting engines in one or both directions. As applied to an electric lift in which the main motor B is automatically slowed and stopped as the cage approaches a floor and, if necessary, an auxiliary motor switched on in the direction of rotation required to bring the cage into exact registration with the floor, the main shaft A, Fig. 2, gear-driven from the motor B, carries a brake-drum E and the driven clutch plate 2, and the auxiliary motor C (shown only in Fig. 5) drives a gear-wheel 7 connected by ball-ended links 9 to the loose clutch plate 5. An adjustable drag-brake 11 (shown only in Figs. 3 and 5) acts on the hub of the plate 5, which is normally disengaged from the plate 2 by separating springs (not shown). In a modification, the links 9 are adjustable by screw-means 15, Fig. 3, and a dustexcluding housing 16 is secured to the hub 14 of the wheel 7, the plates 2, 5 being separated by circumferential centring-springs, which are mounted on arcuate rods 18 carried by the plate 5 and act on either side of lugs 20 on the housing 16. The plate 2 may be axially adjustable along a feather by shims. Centring-springs may be used in the first-described form, the lugs 20 being mounted on the wheel 7. Fig. 5 shows a further construction, in which the links 9 are replaced by flat spring-steel links 21 having a self-centring action to ensure disengagement. The clutch may alternatively be disposed between the motor B and the usual worm drive or on an extension of the transmission shaft A or on a layshaft. The auxiliary motor may be automatically switched on as soon as the main shaft speed has been sufficiently reduced by braking or by increasing the field strength or reducing the armature potential of the main motor. Spring disengaging-means may be dispensed with if the clutch is to act unidirectionally only. The Provisional Specification describes the clutch as applicable to free-wheel drives generally, and includes a form having aligned driving and driven shafts and links in the form of chains, each of which may be enclosed in a spring. It further states that multiple-plate, clutches may be used, and that the auxiliary motor may drive through worm gearing.