From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Specification for an invention relating to improvements in change-speed gearing mechanisms.
| Identifier | ExFiles\Box 136\4\ scan0162 | |
| Date | 1st November 1932 | |
| 4 402,924 the shift lever of the gear pre-selected by the selector shaft the return movement of the camshaft effecting engagement of the gear. Dated the 1st day of November, 1932. A.{Mr Adams} ALLTREE. COMPLETE SPECIFICATION. Improvements in and relating to Change-speed Gearing. 5 I, ARTHUR ALLTREE, a British Subject, of Rydal Dene, Pilling Lane, Preesall, near Fleetwood, in the County of Lancaster, do hereby declare the nature of this invention and in what manner the 10 same is to be performed, to be particularly described and ascertained in and by the following statement:— My invention relates to change-speed gears of the constant mesh type or the 15 sliding gear type, and to gears employing any combination of these types, my invention being specially applicable to any form or arrangement of this class of gearing as used on motor cars, motor cycles 20 or other motor driven vehicles, and my invention may be employed with change speed gears providing any number of speeds forward or reverse, the object of my invention being to provide a simplified control for such gears. 25 The invention comprises the combination with at least one gear shift fork or its equivalent and a lever for operating the same, of means for turning said lever 30 about its pivot to operate the fork, a preselector device for determining which means shall move the lever, and a part which in one direction of movement puts the fork or forks in the neutral position 35 and in the other direction moves the preselected means to turn the lever and through it slide a gear shift fork. Referring to the accompanying sheets of explanatory drawings:— 40 Figures 1—6 illustrate a two speed gear with my improved control means applied thereto. Figure 1 is a plan view of the gear shift fork and connected levers. Figure 2 a sectional side elevation of the 45 complete mechanism, Figure 3 a view similar to Figure 2 but with the parts in a different position, Figure 4 a plan view of the control means with a gear in engagement, Figure 5 a view similar to 50 Figure 1, but with the parts in the positions they occupy when a gear is in engagement and with the gear locking means in position and Figure 6 a detail view of the gear locking and neutralising 55 cam. Figures 7 and 8 illustrate a four speed forward and reverse gear with control means in accordance with this invention. Figure 7 shows the gear shift forks and Figure 8 is a plan view of the control 60 and operating mechanism. Figure 9 is a detail view, showing the flat faces on the selector shaft. Figures 10 and 11 show a motorcycle 65 or compact form of control means in accordance with this invention. Figures 12 to 16 show various detailed modifications of my improved control means. 70 Referring in the first place to Figures 1—5, 2 indicates the gear shift fork which is slidably mounted on a rod 1 suitably supported and mounted in the gear box. The fork 2 is moved in one direction 75 along the rod 1 to effect one gear change and in the opposite direction along such rod to effect a second gear change. The movement of 2 is effected by the shift lever 3 which is pivoted at 4 to the gear 80 box casing and at its free end 3a enters a groove 2a in the fork 2. The lever 3 has two wings 3b and 3c thereon, the functions of which will be described later. A lever 5, which I term a gear neutral- 85 ising shift lever, is pivoted at one end 6 to the gear box casing and at its other end 5a enters the groove 2a in the gear shift fork 2. Upon the lever 5 is a peg 5b which enters a cam groove having in- 90 clined walls 7a, 7b (see Figure 5) in a neutralising cam-shaft 7 which is mounted in suitable bearings in the gear box at its opposite ends. One end of the shaft is shown in Figure 4. Pivoted on a pin 95 7c mounted in the camshaft 7 are two link bars or arms 8 and 12, each of which has a peg, roller or the like (as 8a Figure 2) depending therefrom which when so 100 allowed can engage the wings 3b and 3c of the lever 3. A spring as 10 on cover plate 11a bears upon each link bar 8, 12 to tend to press the peg or roller thereon into engagement with the aforesaid wings 105 but the downward movement of the link bars is controlled by a selector shaft 9 parallel with the rod 1, such shaft 9 having slots or flats as 9a thereon. When one of the latter is brought beneath a 110 link bar, the latter can move into engagement with a wing of the lever 3 as hereinafter more fully described. It will be seen by reference to Figure 5 402,924 5, that if the cam shaft 7 be turned to the left, the cam face 7a will engage the peg 5b, and move it to a mid-position in the apex between the cam faces 7a and 7b. 5 This will cause the lever 5 to move the shift fork 2 to a neutral position. It will be seen therefore that when a gear has been engaged, turning of the camshaft 7 always results in neutralising the gears. 10 With the parts in the positions shown in Figures 1 and 2, if the flat 9a is brought beneath the link bar 8, such bar is allowed to rest with its peg or roller 8a upon the wing 3b. If now the cam- 15 shaft 7 be turned in a clockwise direction, a cam face 7a or 7b will move the peg 5b to a neutral position and the link arm peg or roller 8a will be moved beyond the wing 3b so that it can fall behind it as 20 shown in Figure 3. A movement of the cam shaft 7 in an anti-clockwise direction will now cause the link arm 8 to turn the lever 3 about its pivot as shown in Figure 4 and so effect an axial movement of the 25 shift fork 2 and of the neutralising lever 5. The peg 5b on the latter will now pass into the groove 7d (see Figure 6) in the cam groove of the cam shaft 7. If the other gear is to be engaged, the 30 selector shaft 9 is turned to bring its flat 9b beneath the link bar 12. The gear is however still held in engagement by the lever 5 which is locked by the peg 5b and cam groove. The camshaft 7 is now 35 turned in a clockwise direction which puts the peg 5b and so the lever 5 and shift fork 2 in a neutral position. It also allows the peg or roller on the link arm 12 to fall behind the wing 3c of the lever 40 3. When the cam shaft 7 is now turned in an anti-clockwise direction, the link bar pulls the wing 3c and turns the lever 3 about its fulcrum so moving the shift fork 2 in the opposite direction to that 45 shown in Figure 4. The peg 5b is now in the recess 7e. 7f indicates the neutral position of the peg 5b when the gear is locked in neutral. I may provide guides 13 with slots 13a 50 and 13b therein to strengthen the link bars against lateral thrusts. The selector shaft 9 may be turned by a toothed quadrant 14 engaging a pinion 15 on the shaft 9, the quadrant may be 55 turned by a lever 16 which may be disposed or be connected to a further lever for convenient manipulation. The said lever serves for the selection of the gear to be engaged and the cam shaft 7 serves 60 to neutralise all gears and then to engage the selected gear. Figures 7, 8 and 9 illustrate my invention arranged in combination with a change-speed gear providing four forward 65 speeds and one reverse speed but it will be understood that this arrangement of my invention may be used with other layouts of the gear members providing a similar number of speeds. The levers 3 and 5 70 of Figures 1—4 are duplicated for the four forward speeds and a lever as 3 but with one wing only is combined with a lever as 5 of Figure 3 to give the reverse gear drive. There are pegs and cam slots for 75 each lever as 3 of Figures 1—4. The selector shaft has a flat (9a, 9b, 9c, 9d, 9e) for each link bar (12, 8, 30, 29, 31). There are three shift forks 2, 21 and 22 upon the rod 1. The shift fork 2 may shift 80 a dog or equivalent clutch 18 into engagement with teeth 19a on the primary shaft pinion 19 to give top gear and into engagement with dogs- or teeth 20a on a loose gear wheel 20 to obtain third speed. 85 The fork 21 slides the large gear wheel 24 to engage dogs or teeth 23a formed on the loose gear wheel 23 to give the second speed or to engage a pinion on the lay shaft for the first speed. The shift fork 90 22 engages the reversing pinions. It is thought that the operation of the four speed and reverse gear box will be clear from a consideration of the two speed gear shown in Figures 1—4. In each case, 95 the selector shaft 9 determines the gear to be brought into service, and the cam shaft 7 first neutralises the gears and then brings the selected gear into use. If desired, the selector shaft 9 may be 100 arranged above instead of below the link arms, the latter being then pressed upwards to engage the wings of the levers as 3 which move the gear shift forks. The portions of the wings upon the 105 levers as 3 may be adjustable or may be so given to give the said levers greater or less angular movement for any predetermined movement of the link bars. Figures 10 and 11 illustrate a modified 110 arrangement of my invention for use with small gearboxes such as are commonly used on motor cycles and like vehicles, my invention being applicable to any form of constant mesh or sliding gear used with 115 this type of vehicle. As shown in Figures 10 and 11 the shift forks 2 and 21 are arranged to slide mating gear wheels 32 and 33 in pairs but the arrangement is substantially the same when the shift 120 forks are employed to slide single gear members, dog clutches or other gear members, on either the mainshaft or layshaft or on both shafts. It will be noted that the pegs 2b which enter the cam slots in 125 the cam shaft 7 are now formed directly upon the shift forks 2 and 21 instead of upon separate levers as in the previous constructions. The shift forks 2 and 21 are shown arranged to slide mating gear 130 wheels such as 32 and 33 in pairs although | ||