Patent GB-644836-A (GB)
Title: Improvements in or relating to change-speed gears for motor road vehicles
IPC: F16H3/12
Filed: 1948-04-20
Abstract: 644,836. Change-speed control; clutches. CAHILL, T., and PHILLIPS, L. April 20, 1948, No. 10905. [Class 80(ii)] Means for facilitating the engagement of motor vehicle change-speed gear positive clutches D<SP>5</SP>, D<SP>6</SP>, Fig. 1, connecting a driven shaft D to gears D<SP>1</SP> rotatable thereon and 'in constant mesh with layshaft gears F<SP>1</SP> constantly driven from a main clutch shaft B via gears B<SP>3</SP>, F<SP>3</SP>, comprises two auxilielement K closely enough to assist in cenary friction clutches K, K<SP>2</SP> which connect the shafts D, F' through a nearly or exactly 1 to 1 ratio gear pair J, J<SP>2</SP> when the main 'clutch pedal P<SP>6</SP>, Fig. 3, is depressed beyond its normal position of clutch disengagement. The gears J, J<SP>2</SP> have the male elements K of the auxiliary clutches bolted thereto and are rotatable on hard steel bearing sleeves H<SP>2</SP> mounted in a carrier G<SP>2</SP> which is axially slidable on four guides G<SP>3</SP>, against the pressure of gaitered springs G<SP>4</SP>, under the thrust of four symmetrically disposed studs M<SP>3</SP>, Fig. 3, adjustably screwmounted in two frames M pivoted to the gear casing and turnable by tension rods N from the pedal P<SP>6</SP> through cranks P<SP>1</SP> and racks and pinions P<SP>4</SP>, P<SP>3</SP>. The studs M<SP>3</SP> provide initial adjustment of the frames, which are resiliently pressed against the carrier G by chatter-preventing springs M<SP>5</SP> on studs M<SP>4</SP> passing freely through slots M<SP>6</SP> in the frames to engage the carrier. Further adjustment is allowed by nuts N<SP>2</SP> on the ends of the tension rods N. Clearance is provided between the extension C of the shaft D, which carries one female clutch element K<SP>2</SP>, and the corresponding sleeve H<SP>2</SP>, but the other sleeve H<SP>2</SP> is for centralizing purposes, a sliding fit on an extension C<SP>1</SP> of the stationary bearing spindle F<SP>5</SP> of the layshaft gears, which are integral with a sleeve F carrying the other female clutch element K<SP>2</SP>. Alternatively, the. extension. C<SP>1</SP> may be shortened to a spigot engaging in the corresponding clutch element K only, a solid bearing member H<SP>2</SP> being used in conjunction therewith. The shaft C may have an enlarged portion fitting the corresponding tralizing the latter. The male clutch elements K may be secured to their gear wheels by studs allowing assembly with the gear wheels in position. The sleeves H<SP>2</SP> may have a taper fit in the carrier instead of a cylindrical fit as shown, or may be in threaded engagement therewith. Two alternative forms of thrust frame are described, each having a single member pivoted at one side of the gear casing. In one case, the member forms a lever of the second order, bearing on the carrier through centrally disposed rounded bearing elements and being acted on by a single tension rod actuated as before. In the other case, the member forms a lever of the first order, bearing on the carrier through centrally-disposed rollers, and being acted on by a single thrust rod which may be actuated directly by a crank on the spindle of the clutch pedal. To assist final synchronization of the clutches D<SP>5</SP>, D<SP>6</SP> the positive clutch elements D<SP>5</SP>, Fig. 9; on the driven shaft may have collars Y' co-acting frictionally with finger portions X<SP>2</SP> of a spring metal ring secured to the co-acting gear D' before the positive clutch elements engage.