Patent GB-566411-A (GB)
Title: Improvements in or relating to change-speed transmissions
IPC: F16H3/12
Filed: 1941-09-18
Abstract: 566,411. Variable-speed gearing. NEW PRODUCTS CORPORATION. Sept. 18, 1941, No. 11989. Convention date, Sept. 19, 1940. [Class 80 (ii)] Variable-speed gearing giving four ahead speeds and reverse, with automatic change from first. to third, or from second to fourth, with alternative manual control, embodies a gear - box having a countershaft 42, Fig. 1, driven at reduced speed through gearing 33, 34, and a one-way clutch 47 from a driving shaft 26. Shaft 42 has gears 58, 59 meshing with gears 61, 62, selectively clutchable to the driven shaft 27. A clutch member 63 splined to the driven shaft 27 has, on opposite sides, clutch teeth 64, 67, engageable with teeth 66, 69 on the gears 61, 62. A second clutch member 85 splined to the gear 61 has repelling clutch teeth 84 engageable with teeth 83 on the end of the driving shaf 26. A third clutch member 52 splined to the inner member 48 of the one-way clutch 47 has teeth 51 which when engaged with teeth 50 on the gear 34 locks the one-way clutch 47. A gear 75 on the clutch member 63, when the latter is in its neutral position, can be driven by a gear 60 on the countershaft 42 through an idler 76 on a third shaft 77 to give a reverse drive when the clutch teeth 50, 51 are engaged. For first speed the clutch 64, 66 is engaged and the drive is through the members 26, 33, 34, 47, 58, 61, 63, 27. For second speed clutch 67, 69 is engaged and the drive is through 26, 33, 34, 47, 59, 62, 63, 27.The third speed (one-to-one) is obtained by engaging clutches 83, 84 and 64, 66. Engagement of clutches 83, 84 and 67, 69 gives the highest speed, the drive taking place through 26, 33, 85, 61, 58, 42, 59, 62, 63, 27. The clutches instead of having repelling teeth may be replaced by other forms of synchronising clutches, e.g. the blocker type, or ordinary dog clutches may be used. Movement of the clutch members 63, 85 and 52 and of the reverse gear 76 is controlled by a camplate 136, Fig. 3. The connection between the cam 136 and clutch member 63 includes an arm 124 on a cross-shaft 119, a shifter fork 74 being pivoted to the shaft 119 and connected thereto by a pair of wind-up springs to give a pre-selector effect. A shifter fork 90 for the clutch member 85 is fixed to a cross-shaft 91 having an arm 148 engaging the cam 136 and arms 93, 202, Fig. 5. A spring 94 tends to turn the shaft 91 to engage the clutch 85, but such movement may be prevented by the engagement of a stud 100 with a notch 99 in a cam 98 carried by a spindle'96. The latter has an arm 101 connected (i) to a hand-operable rod 218; (ii) to a rod 114 linked to a speed responsive device 103, Fig. 1; and (iii) to a holding spring 115. If the cam 98 is moved anti-clockwise, Fig. 5, movement of the clutch member 85 is permitted. Disengagement of the clutch 85 at any time may be effected by depression of the heel of the accelerator pedal 203, Fig. 5a, which causes the closing of an electric circuit including a solenoid S, Fig. 5, whereupon the armature 200 connected to the arm 202 overcomes the spring 94 and turns the cross-shaft 91. The cam-plate 136 is moved manually to one position, Fig. 7 (not shown), for first and third speeds, to another position, Fig. 8 (not shown), for second and fourth speeds, and to a third position, Fig. 9 (not shown), for reverse speeds. Thus, when the gearing is running at first or second speeds, movement of the clutch 85 by means of the speed responsive device 103 will introduce automatically third or fourth speeds respectively, and the first or second speeds may be regained by depression of the heel of the accelerator pedal. In a modification, in which the highest speed ratio is one-to-one, a second one-way clutch 254, Fig. 16 (not shown), is used between a gear 247 in the low-speed train and the driven shaft 252, the reverse gear 250 being splined directly to the driven shaft 252 instead of being formed on one of the clutch members. The low gear drive includes a dog clutch 237. In this construction, the cam 98 of Fig. 5 is replaced by a cam 305, Fig. 18 (not shown), concentric with the main cam 294 so that studs 343, 325 of control levers 344, 326 are under the control of both cams. Specification 542,439 is referred to.