Patent GB-331258-A (GB)
Title: Improvements in and relating to power transmission mechanism for motor cycles and the like
IPC: F16D23/06
Filed: 1929-03-26
Abstract: 331,258. Alltree, A. March 26, 1929. Divided on 330,039 and 331,293, [both in Class 80 (ii), Gearing, Variable speed &c.]. Clutches, arrangements and applications of.- The final-drive sprocket of a motor-cycle is coupled to its shaft or sleeve by a positive clutch adapted to be engaged only when its members run in approximate synchronism. The primary gear-box shaft a, Fig. 1, is driven from a friction clutch g, and the final-drive sleeve b has loose thereon a sprocket d provided with claws d' to engage claws f<1> on a member f slidable on splines b<3> of the sleeve b. The member f is connected by adjustable rods g<2> to the sliding member g<1> of the clutch g, which is actuated by an internal rod h having sufficient travel to disengage the claw clutch after the friction clutch. When the sprocket d overruns the sleeve b, the drag on the member f of a spring-pressed friction ring i, connected to the sprocket, causes the splines of the part f to enter recesses b<4> at the end of the splines b<3> and so prevent re-engagement of the claw clutch until the sleeve b overtakes the sprocket d. The recesses may alternatively be formed in the member f. A single rod g<2> may act on the part f through a pivoted fork, Fig. 11 (not shown), to give increased motion thereto. In a modification, Fig. 4 (not shown), the part f slides on recessed splines on an extended boss of the loose sprocket, the friction ring being carried on pins projecting from a plate, which is fixed on the shaft b and is provided with the coacting clutch claws. In another modification, Fig. 8 (not shown), the friction clutch is at the opposite end of the gear-box, the member f being actuated by linkage interconnected with the friction-clutch control, and the recessed splines being formed directly on the shaft b or on a member secured thereto. The friction-ring springs may be on the gear-box side of the sprocket d. In another form, Fig. 9 (not shown), the sprocket d is secured to a flanged hub on which the clutch claws are formed, and the sliding member f is pressed by a spring concentric with the shaft. The claw-clutch members may alternatively be held apart by a separate medium such as an external ring or balls, rollers, &c. Fig. 5 shows an arrangement in which a thin sleeve k fulfils this function. Splines f<3> on the member f pass through slots in the sleeve k to engage splines on the shaft b, the slots having terminal recesses k<1> to receive the splines f on overrunning. A single or multiple coil spring band l, anchored at one end l<1> to the loose sprocket d, is arranged to give a slight drag on the sleeve k during overrunning and to grip it firmly when it is to be restored to allow clutch engagement. The band l may engage a small flange or groove on the sleeve k to hold it against axial movement. The member f is withdrawn by a cross-piece m, which engages with clearance a groove therein and lies between the two parts h, h<1>, of the friction-clutch actuating-rod, the claw clutch being recoupled by a spring n acting on the piece m. Recesses may be formed on opposite sides of the splines &c. to prevent clutch engagement also when the driving-member runs ahead of the driven member. Thus, the thin sleeve k may have two sets of recesses k<1>, k<2>, Fig. 6, in line or, as shown, staggered. In another modification, Fig. 10, the claws f<1> on the member f engage recesses d<3> in the claws d<1> of the sprocket d during coasting and coact with dogs b<5> on the sleeve b during drive, the part f being thrust by a spring-pressed friction ring r rotated with the sleeve b by pins r<1>. The sprocket d may be provided with an additional set of claws d<4>, Fig. 12, with which the claws Y can be engaged to restore drive before synchronism, as when the momentum of the vehicle is required for restarting the engine. The splines on the sleeve b are then formed with a second deeper set of recesses b<6>. The double set of claws may alternatively be provided on the part f. The invention is applicable also where the sprocket is on a bevel or worm driven shaft transverse to the gear-box shaft. The first Provisional Specification describes an arrangement for coupling the gear-box and propeller shafts of a motor-vehicle, but applicable also to motor-cycle chain-drive sprockets, wherein the slidable member of a dog clutch with facial or radial teeth is held disengaged by one or more pegs thereon engaging one or more helical channels, with or without a terminal seating or seatings, formed in a short bar frictionally contacting with a bore in the gear-box or propeller shaft. The second Provisional Specification describes a form, applied. to motor vehicles, in which a sleeve has internal splines at the ends to engage splines on the gearbox and propeller shafts; when the sleeve is shifted axially, one of its sets of splines passes on to a plain end of one shaft, while the other set enters recesses in the splines on the other shaft. The arrangement may be modified for use with facial dog clutches. In another form, the sleeve has continuous splines, adapted, when disengaged from one shaft, to enter recesses in splines on a loose central member, which is spring-pressed against the driving or driven shaft or is acted on by a spring-loaded arm, sleeve, ring, or other drag-device. The central member may alternatively be formed with dogs. As applied to a motor-cycle, the central member is a narrow sleeve disposed in a bore of the finaldrive sprocket, and has dogs to engage dogs on the sliding clutch member. The central member may have opposed seatings, in line or staggered, to prevent clutch engagement for either direction of overrun.