GB465018A - Improvements relating to variable speed gear - Google Patents

Abstract

465,018. Automatic change-speed gearing. STEVENS, F. July 31,1936, No. 21186. [Class 80 (ii)] [Also in Group VIII] Change speed gearing operates automatically to change the ratio in response to torque changes by cam and spring-plunger clutches which slip on overload. Spring plungers a<7>, Fig. 2, sliding in a load wheel A<4> will resist the relative turning of a driving-cam a<5> so that a limited torque is transmitted to the wheel A<4>, the limit being reached when the cam turns under the plungers. Thus when the load on a driven shaft B, Fig. 1, is heavy, slip clutches C, D, E, F all yield, and a positive drive is transmitted from a pinion A<1> fast on a driving- shaft A to a wheel B<1> connected to the shaft B by a one-way clutch b<1>. The central cam a<5> of the clutch C is rigid with the pinion A<1> so that a torque is transmitted through the clutch C as it slips to a wheel A<2> and from that to a wheel B2 and one-way clutch b<2> tending to drive the shaft B faster. If the load falls, this clutch b<2> picks up the drive and the pair A<1>, B<1> overruns at b<1>. The next slip clutch D is transmitting a torque as it slips through the next pair A<3>, B<3> and the next one-way clutch b<3> which picks up the drive when the load is suitable, the clutch b2 of the second pair also overrunning. With the load sufficiently relieved, the drive passes through the slip clutches C, D, E, F in succession and through a pair A<5>, B5 and one-way clutch b<5> yielding a fifth and highest speed. A light gear device for a pedal cycle is described with reference to Figs. 9 and 10 (not shown). A heavier form suitable for a motor vehicle is described with reference to Fig. 7 (not shown). A two-speed form for driving a domestic wringer is described with reference to Fig. 8 (not shown).