Patent GB-394581-A (GB)
Title: Improvements relating to change speed gears
IPC: F16H61/00
Filed: 1932-12-01
Abstract: 394,581. Variable-speed gearing. McTAGGART, W., 128, Marine Parade, PATERSON, J., PATERSON, J. H., 31, Park Crescent, both in Brighton, and WILLIAMS, A. C., 130, Foxley Lane, Purley, Surrey. Dec. 1, 1932, No. 34057. [Class 80 (ii).] A toothed change-speed gear for motor vehicles, provided with means, if desired under the control of a preselector enabling the automatic engagement of gear wheels when they rotate at synchronous peripheral speeds, comprises centrifugal governors 3, 4 driven by the driving-shaft 8 and driven shaft 12 respectively of the gear and jointly serving to move a distributor such, as a spring ball-contact arm on a common bar 25 over a surface such as contact strips 30, 31, 32 set in an insulating plate 21, the path of each strip corresponding to the position of the end of the contact-arm throughout the speed range for a particular ratio. The contact strips are connected to gear-engaging solenoids 42, 43, 45, 46. A contact-strip 33 corresponding to reverse is set in an upper insulating plate 22 and co-operates with an upper spring-arm on the common bar 25. The bar 25 is fixed to the centre of a transverse bar 26 to form a T-bar pivoted at one end 27 to a sleeve 19 slidable on a rod 20 and moved through a fork 18 by the movable sleeve 17 of the driven-shaft governor 4. The bar 26 has at its other end a pin-and-slot connection 29 with a sleeve 15 similarly moved by the driving-shaft governor 3. When the contact-arm 25 is caused, by accelerating or decelerating the engine after disengagement of the main clutch, to lie on one of the contact strips 30, 31, 32 corresponding to a required ratio, the gear-wheels of this ratio are synchronized and if the electrical circuit has been completed by the preselector switch, current will be supplied by the battery to the corresponding gear-engaging solenoid 42, 43, 45 or 46. These solenoids are arranged in pairs having common armatures 34, 44 connected respectively through a pivoted lever 36 and a rod 39 with a gear-striker 40 for first speed and reverse, and a striker 52 for second and high. The strikers are urged to the central position by springs 54. A preselector switch may comprise a dial or scale arranged adjacent the steering wheel of a vehicle and having a lever movable to bridge contacts in the circuits of the relays. Figs. 5 and 6 show a modification suitable for conversion of existing gear sets having a lever 67 depending from a ball-mount 68. The transverse selecting movement of this lever is manually effected by the preselector switch-arm, and its longitudinal gear-engaging movement is effected by the automatic means which requires only two solenoids 42a, 43a. The preselector switch comprises an arm 72 arranged to pivot over a cam-plate 73 having notches, those 74, 75 corresponding to firstspeed and reverse being at a less radius than those 77, 78 for second and high. The notches are engaged by a detent 79 slidable along the preselector arm 72 and connected by a Bowden cable 80 with a yoke 81 surrounding the gear-lever 67 and connected to it by springs 82<1>. A spring 82 holds the detent against the notches. Radial movement of the detent 79 over the cam-plate 73 thus effects transverse movement of the gear-lever 76. The gear-lever 76 also passes through a slot in a lever 36a moved by the single armature 34a to effect its automatic longitudinal gearengaging movement. The interlocked strikers 70 are loaded to the neutral position by springs 54 and are locked in the extreme positions by abutment of spring-loaded detents 85 with the ends of projections 84 on the strikers. The detents 85 are retracted to free the strikers during a change by depression of the main clutch pedal 90 acting through Bowden wires 91. In cases where the preselector is not used, coloured lamps may indicate to the operator which gear is engaged. The clutch-pedal may carry a contact serving to make and break all circuits as it is depressed or released. The reverse, instead of being operated automatically, may be directly operated by a separate switch or by the preselector switch.