Patent GB-331293-A (GB)
Title: Improvements in and relating to power transmission mechanism
IPC: F16D23/08
Filed: 1929-04-12
Abstract: 331,293. Alltree, A. April 12, 1929. Clutches, claw; facilitating changing speed. - In claw clutches for automatically coupling together two shafts or other members when they run in approximate synchronism, applicable as coasting or isolating clutches on motor vehicles, the clutch members are held apart by the displacement of torquetransmitting parts into seatings or recesses provided on the shafts or clutch members themselves, without the use of intermediate baulking- rings, balls, rollers, or the like. The gear-box tail shaft a, Fig. 3, has short splines a<1> and a plain end a<2>, the propeller-shaft b (or shaft coupled thereto) having splines b<1> with recesses b<2>. A slidable coupling-sleeve c, having coacting dogs c', c<2>, can be withdrawn against a spring d, so that, as shown, the dogs c<1> are clear of the splines a' and, when the shaft b overruns, the friction between the tightly-fitting dogs c<1> and the cylindrical part a<2> moves the dogs c<2> into the recesses b<2>. The clutch can then re-engage only when shaft a overtakes shaft b. The friction may be augmented by spring-loaded or springy arms e<1> on a member e slidable on the splines a<1>. In order to prevent clutch re-engagement when shaft a runs ahead of shaft b, the splines b<1> may have also opposed recesses b<3>, Fig. 5, which may be in line with the recesses b<2> or, as shown, staggered therefrom. In a modification, Fig. 6 (not shown), the dogs c<2> are omitted, the does c' extending the full length of the sleeve c, which must then be so far withdrawn from the shaft a that the dogs c<1> can enter the recesses b<2>, a separate friction member, such as e, being necessarily provided. The sliding member c and a member g, Fig. 7, fast on shaft a, may have facial dogs c<5>, g<1>, the member c being displaced on the splines of shaft b by a friction ring or segments c<6> pressed into a groove c<3> by spring arms t<1> on a sleeve t slidable on the part g. In a modification, Fig. 8 (not shown), the part g has internal dogs and the part c external coacting splines, with which slidably engages also a spring- armed friction member adapted to grip the part g. The sliding member c has one or more sets of internal splines coacting with a like number of recesses in the splines of shaft b. In another modification of the form described with reference to Fig. 3, there are provided a second set of splines, Fig. 9 (not shown), on shaft a beyond the plain part a<2> and a set of deeper recesses beyond the recesses b<2> on the splines b<1>, so that, by shifting sleeve c further to the right, drive can be restored without synchronism, as when the engine is to be restarted by momentum of the vehicle. In another form, Fig. 12 (not shown), the recesses or seatings are provided in the dogs c<2> of the sleeve c. In the construction shown in Fig. 10, the member c has dogs c<10> adapted to be engaged with dogs b<7> on shaft b and dogs c' slidably engaging dogs g<1> on the driving-member g. The dogs c<10>, b<7> are held apart during overrunning by recesses c<9> in the dogs c<1>, or similar recesses in the dogs g', the member c being acted on by a friction ring f turning with shaft b. As applied to a chain-wheel v, Fig. 11, for purposes other than motor-cycle drives (which application is claimed in Specification 331,258), dogs v<4> thereon are engageable with dogs c<5> on a member c slidable on recessed splines on a shaft w or member w<1> secured thereto, a spring-pressed friction ring v<2> being carried by the wheel. In any of the forms, the recesses or seatings may alternatively be formed on the driving-member, and the part c may be operated from the engineclutch control, from the gear-lever, or directly from the sliding member of the engine clutch by means of an internal rod in the gear-box shafts and cross-pieces projecting therethrough. The Provisional Specification describes also a. form in which an intermediate member is disposed between the shafts and bears on one of them, and this member may have two sets of aligned or staggered recesses, as shown in Fig. 5.