Patent GB-449540-A (GB)
Title: Improvements in and relating to change speed gears
IPC: F16H3/12
Filed: 1934-12-27
Abstract: 449,540. Change - speed gearing. DAIMLER-BENZ AKT.-GES., Unterturkheim, Stuttgart, Germany. Dec. 27, 1934, No. 37057. Convention date, Dec. 27, 1933. [Class 80 (ii)] In change-speed gearing suitable for vehicles, means for facilitating the speed-changing comprises a control member which, when moved in one speed-changing direction, acts as a synchronizing clutch p<2>, Fig. 1, and, when moved in the other speed-changing direction, acts as a synchronizing brake p<1>. The clutch p<2> synchronizes clutch teeth h<2> at the right end of a sleeve h which is splined on the driven shaft b of a four-speed gear. The clutch teeth h<2> are engaged with teeth f <3> in the boss of a loose gear f to bring in second speed, the first speed being brought in by sliding a wheel i<1> into mesh with a pinion i<2> on a countershaft c. The brake p<1> synchronizes clutch teeth h<1> on the left end of the sleeve h which are engaged with teeth e<3> on a gear e<1> to bring in third speed when the gear e<1> is engaged, as shown, by a double clutch g slidably splined on a driving-shaft a. A selector bar k<2> is connected by a fork k<4> to the sleeve h to effect the two synchronized engagements. The bar k<2> has a T end k<1>2, Fig. 3, which has a spring ball engagement q between arms n<1>, n<2>, Fig. 2, of a striking lever n which is supported on two pivots n<4> so as to act with increased leverage on a pair of cheeks o. The cheeks ride in a groove between a plate p <1> and a ball bearing t carried by a sleeve p which is splined on an extended boss of the gear f<1>. When the bar k<2> is slid right for second speed, the spring balls q engage and carry the lever n along so that the cheeks o through the ball bearing t thrust a clutch bell p<2> on the sleeve p into engagement with a clutch bell s fast on the shaft b. The clutch teeth h<2> are thus brought to the same speed as the clutch teeth f<3> so that, after the spring balls q have slipped over the arms n<1>, n<2>, the bar k<2> and sleeve h can move on to bring the clutch teeth h<2> into full shockless engagement. Friction is intentionally left between the cheeks o and the plate p<1> so that when the bar k<2> is moved left to bring in third speed, these cheeks exert braking on the plate. As the second speed is being disengaged, the clutch teeth e3 of the gear e<1> are rotating faster than the teeth h<1> on the sleeve h, and this braking of the plate p<1> is transmitted through the train f<1>, f<2>, e<2>, e<1> so as to slow the teeth e<3> to the speed of the teeth h<1> prior to shockless engagement, so effecting third speed, which is a direct drive. To bring in fourth speed, which is an overdrive through the train d<1>, d<2>, e<2>, el, h, b, a selector bar k<3>, Fig. 4, is moved right, whereby a bell-crank lever m<1> is thrown clockwise so that the end m<1>1 of its long arm reaches position m<11>1. A spring m<2> then pulls on the long arm m<1>3 of a second bell-crank m<3> so that the short arm tends to throw the double clutch g, Fig. 1, left. The clutch g remains as shown until the engine throttle is partly closed, whereupon driving thrust on the clutch teeth eases and the spring m<2>, Fig. 4, is able to throw the bell-crank m<3> and clutch g right over. The teeth of the double clutch g are inclined at their ends to facilitate engagement, as described in Specification 298,186, [Class 80 (ii)].