Patent GB-863325-A (GB)
Title: A successive gear-changing device in conjunction with a selector
IPC: B62M25/00
Filed: 1958-04-30
Abstract: 863,325. Change-speed control. ZAVODY 9 KVETNA, NARODNI PODNIK.. April 30, 1958 [May 3, 1957], No. 13748/58. Class 80 (2). A change-speed control-mechanism provides for successive gear changing, both up and down, and also includes a pre-selector permitting engagement of the gears in any order. As described for a change-speed gear for single-track vehicles having a gear-box providing four forward ratios, shift forks 19, 20 are located in diamond-shaped slots of shift members 9, 10 which are axially slidably keyed to a shaft 2. The shift forks are also mounted on the shaft 2 and have pins 29, 30 co-operating with peripheral grooves 23-28 and longitudinal grooves 31, 32 in the shaft. Shaft 2 carries a sector 4 meshing with a sector 5 having a lost-motion connection with a shaft 3. A pre-selector lever 74 is rotatable into positions corresponding to the four ratios and neutral; rotation of the lever 74 acting, through a key 73 on the lever spindle engaging a slot in a disc 70, to actuate a cable mechanism which rotates a plate 33. Plate 33 has cam slots co-operating with pins 14, 15 of sleeves 12, 13 which are loosely mounted on the shaft 2, so that rotation of plate 33 moves sleeves 12, 13 axially of shaft 2 and these sleeves carry the shift members 9, 10 with them. To establish a ratio a lever 52 is moved up or down from its initial position, thus rotating the shaft 3 which is fast with a cam 61 for disengaging the main driving clutch. When the lost-motion is taken up shaft 3 rotates the shaft 2 through the sectors 5, 4, this rotation bringing the grooves 31, 32 into register with the shift fork pins. The shift members 9, 10 rotate with shaft 2 and the edges of the diamond-shaped slots in these members move the shift forks axially until the forks lie in the ends of the diamond-shaped slots, thus engaging the appropriate gear. The grooves 31, 32 are of sufficient width to permit this. On releasing the control lever 52, shaft 2 is returned to its initial position by springs 8, so that the shift forks are retained in position by the peripheral grooves, and shaft 3 is returned to its initial position by a spring 64 so that cam 61 engages the clutch. For successive changing the pre-selector lever 74 is depressed against spring-loading to bring key 73 beneath the disc 70 and into engagement with a slot in a disc 67. Rotation of lever 74 beyond the neutral position to a successive shift position then rotates disc 67 which, through a cable mechanism, lowers a pawl carrier 54 against spring action, until two spring-loaded pawls are brought into register with windows in a stationary base-plate 35. Lever 52 is moved downwardly for up-shift and upwardly for down-shift, initial rotation of shaft 3 again disengaging the clutch, and also rocking the pawl mechanism. The cam-plate 33 has recesses co-operating with the pawls so that the cam-plate is moved one step for each movement of lever 52. When the cam-plate has completed its movement an edge of a window in the base-plate raises the operative pawl out of engagement with the cam-plate; at this point the lost-motion between shafts 2, 3 has been taken up and further rotation of shaft 3 rotates the shaft 2 so that the shift forks are actuated as described above. Since the cam-plate 33 is coupled to the disc 70.by its cable mechanism, an indicator 75 on the disc 70 shows which gear is engaged. If the gear-box includes a reverse gear, a third selector fork and associated mechanism are provided, and are actuated by a third slot in the cam-plate, reverse being selected by turning the pre-selector lever to a position between its neutral and successive change positions and being established by actuation of the control lever 52.