Patent GB-406316-A (GB)
Title: Improvements in or relating to variable speed power transmission mechanism
IPC: F16H3/12
Filed: 1932-08-22
Abstract: 406,316. Facilitating changing speed. NAPIER & SON, Ltd., D., WILKINSON, G. S., 211, Acton Vale, Acton, and SEWELL, C. W., 2, Holly Park, Finchley, both in London. Aug. 22, 1932, No. 23502. [Class 80 (ii).] Change-speed gearing suitable for vehicles in which the changes are effected by changing the engagement of toothed wheels or claw clutches is combined with auxiliary synchronizing constant-mesh variable-speed gearing having a separate slipping clutch on each ratio. The first part of a speed-changing movement applies the synchronizing slipping clutch, and inclined shoulders 78, Fig. 3, in the control prevent the change being effected before synchronization. In Fig. 1, the main change gearing is the four-speed arrangement described in Specification 406,313 which has a synchronizing sleeve 53 integral with a gear 52 constantly driven through the lay shaft 48 from the driving-shaft 43, and the lay shaft 48 extended at 48a to form a second synchronizing member. To synchronize the third speed clutch 62, 63, the synchronizing sleeve 53 is clutched to the driven shaft 45 by a friction cone 68. A wheel 80 fast on the extension 48a with its mating pinion 65 loose on the shaft 45 correspond to the main gear pair 50, 49. The fourth speed or direct-drive clutch 60, 61 is synchronized by engaging a friction cone 67. An auxiliary pair 79, 64, the latter being fixed, correspond to the main gear pair 57, 54, and second speed is synchronized by engaging a friction cone 82 splined on the extension 48a. The first speed is not synchronized. The two cones 67, 68 are secured to a barrel 70, Figs. 2 and 3, which is constrained to revolve with a sleeve 71 splined on the shaft 45. Leaf springs 72 hold the cones normally in neutral. The inner sleeve 71 is connected to a striking ring 73 engaged by a control fork 74 by stems 76 which pass through openings 77 in the barrel 70 such openings having inclined shoulders 78, Fig. 3, which are engaged by the stems 76 so that the fork 74 thrusts the selected clutch cone into engagement. Upon synchronization, the stems 76 slip past the shoulders 78 allowing the gear change to be completed and the engaged cone to be withdrawn by the springs 72. The cone 82 is provided with a similar single-acting shouldered control with a fork 85. The coupled main pinions 57, 58 are operated by a fork 59, Fig. 5, secured to a sliding selector 90. The coupled wheels 54, 55 are operated by a fork 56 secured to a sliding selector 88. In the position shown, a selector arm 92 on a control shaft 93 operated from a gate engages the forked upper ends of levers 91, 102 pivoted upon the selectors 88, 90, respectively. The initial rocking of the arm 92 to change speed rocks both these levers. The rocking of the lever 102 unlocks the selector 90 by means shown in Fig. 8. The rocking of the lever 91 operates the synchronizing cone 67 or 68 by means shown in Figs. 10, 11, and 12. Continued rocking of the arm 92 then slides both selectors 88, 90 to engage the clutches 61 and 63, Fig. 1, alternatively, for fourth and third speeds while preventing the toothed gears from mutually engaging. To select first and second speeds, the arm 92, Fig. 5, is slid so as to disengage the lever 91 and, while remaining engaged with the lever 102, to engage the forked upper end of a lever 104 which is connected through a link 109, Fig. 8, to the fork 85, Fig. 1, of the synchronizing cone 82. The initial rocking move. ment of the arm 92 towards second speed position rocks the lever 104 as shown in Fig. 8 so as to rock a slotted lever 106 and so pull the synchronizing rod 109 while the sliding selector 90 is still locked by a snug 103a moving in a cross slot 95. After substantial synchroniza. tion, the snug 103a drops clear of the slot 95 and continued rocking of the arm 92 then carries the selector 90 with it to engage the main gears 57, 54 for second speed. Figs. 10, 11, and 12 show the double-acting arrangement when the selectors 88, 90 are being slid together to alternative synchronized positions. The initial rocking of the arm 92 from the neutral position of Fig. 10 to the position of Fig. 11 depresses a slotted lever 98 about a fixed pivot 99 so as to pull or push, according to the speed selected, a link 101 which is connected to the double-acting synchronizing fork 74 of Figs. 1 and 2. It is only after substantial synchronization that a locking snug 94a is raised clear of a cross slot 95a so as to render possible continued striking movement of the arm 92 to the gearengaged position of Fig. 12.