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).
Patent specification for a change-speed gear control mechanism.
| Identifier | ExFiles\Box 136\4\ scan0156 | |
| Date | 6th July 1935 guessed | |
| 4 438,068 sary for the downward changes, means are provided to make the pawl operative or inoperative at will. In one arrangement this is effected by 5 mounting a cam 22 on the shaft 2 and connecting this cam to a suitable lever by means of which the position of the cam may be controlled. As shown in Figure 5 the cam 22 is in a position that permits 10 the pawl 20a to engage with the ratchet teeth 2d, but, as in Figure 6, by giving the cam a partial turn it can be moved to a position that prevents the pawl engaging the ratchet teeth. With the cam in 15 this position and the pawl inoperative the pre-selector lever can be used in its normal manner. Figures 8 and 9 illustrate a modification in the means for giving the necessary 20 movement to the pawl. In this arrangement the pawl carrier takes the form of a toothed wheel or segment 23 that meshes with a toothed wheel or segment 24 secured to or integral with the shaft 1. A 25 partial turn of shaft 1 turns the toothed member 23 and pawl 20a the latter then functioning as described with reference to Figure 4. When desirable a part 20c of the pawl 20a may project through a suit- 30 able slot in the pawl carrier, as in Figure 9, the projecting part lying in the path of the cam 22 by which it can be raised to make the pawl inoperative. Figure 10 illustrates a development of 35 my invention that provides this form of gear selection on both downward and upward gear changes. Two sets of ratchet teeth as indicated by 2d and 2f provide for a clockwise or anti-clockwise turning 40 of shaft 2 the pawl 20a giving the former and the pawl 20b the latter of the two movements. Each pawl is mounted on its own pawl carrier and both carriers are given the necessary partial turn in the 45 manner already described in reference to one pawl excepting that the second pawl carrier for the downward changes is turned anti-clockwise. The cam 22 can be moved to make both pawls inoperative 50 or to make either pawl operative. When it is desirable to give the cam 22 a large turning movement this can be done by employing the arrangement shown in Figure 11 in which the cam is 55 formed upon or secured to a disc or plate 25a having teeth that mesh with teeth in a hand-controlled quadrant 25 by which the member 25a is turned. Figure 12 shows an alternative construc- 60 tion of my invention in which the pawl carrier 20 is mounted upon the pivot pin 3a of a toothed quadrant 3 when such is employed to turn the small gear 2c on the selector shaft 2 the pawl 20a turning the 65 member 3 through the medium of ratchet teeth 3b formed on or secured to member 3. When the shaft 1 is given a partial turn, as when gear changing, the movement is transmitted by the link 21 to the 70 pawl carrier 20 and pawl 20a and thence through ratchet teeth 3b and member 3 to the gear 2c and selector shaft 2 the latter being turned to the extent required for the next upward change. The cam 22 is 75 mounted adjacent to the pawl carrier on the pin 3a and by means of it the pawl can be made operative or inoperative in the manner already described herein. Figure 13 illustrates a development of 80 the construction shown in Figure 12 which permits this form of self-contained gear selection to be made on both upward and downward gear changes. The pawls or arms 21a and 21b are pivoted upon a pin 85 on shaft 1 the arm 21a being adapted to engage ratchet teeth 3c for the changes in one direction and the arm 21b adapted to engage ratchet teeth 3b for changes in the other direction. The cam 22 can be 90 moved to make both arms inoperative or moved to permit either arm to become operative the Figure showing arm 21a operative and arm 21b inoperative. The free ends of the arms may be formed with 95 a plain part that can bear on the cam, as shown at 21d in Figure 13a in which 21e is the tooth face. A single arm for the upward changes can be employed in place of two arms. 100 This construction may be employed to arrange that the pre-selector member is turned by a pawl carrier, when the arrangement of shaft 1 and shaft 2 is favourable to its use. 105 To facilitate control of the cam 22 I may employ a simple lever separate from the lever that controls the selector shaft 2 in its normal use, in which the desired gear is pre-selected by means of a hand-con- 110 trolled lever, but, alternatively, I may control the cam by means of the normal pre-selector lever. Figures 14 and 15 show how the cam and selector shaft are controlled by means of the one lever. The 115 selector shaft is normally controlled by a lever formed in two parts 26 26a the former being pivoted to the latter at 26b. The portion 26 is extended and this extension 26c is coupled to a rod 27 the lower 120 end 27a of which is suitably connected to the cam. The normal control to the selector shaft or quadrant 3 is taken from the lower end 26f of the hollow rod 26d within which the rod 27 is free to slide. 125 When the lever 26 is in the position shown by the full lines the cam 22 herein described is in its operative position and the control is used normally. By tilting the end of lever 26 into the position indi- 130 cated by the broken lines the rod 27 is moved downwards inside the hollow rod 26d and as the rod 27 is connected to the cam the latter is moved into its inoperative position and so permits the pawl to 5 function in the manner already described. As the lever 26 is now clear of the notches 28a in the fixed quadrant 28 it moves in step with the selector shaft so that at any time the normal control may 10 be restored simply by pushing the lever down on the quadrant 28, as indicated by the full lines, without disturbing the correct position of the selector lever. Figures 16 and 17 illustrate a modifica- 15 tion in which the rod 27 is moved by a small lever 29 mounted on a normal preselector lever 30 the small lever moving between the positions indicated by full and broken lines: In this arrangement, 20 as also in Figure 14, a spring-loaded plunger 31 may be provided to position the rod 27 by engaging notches 31a and 31b in the rod the notches corresponding with the two positions of the lever 29 and 25 the cam it controls. Lever 30 is of flexible construction so that it can ride over the notches 28a. When the cam has three positions, as described with reference to Figures 10 and 13, the lever 26 in Figure 30 14 and lever 29 in Figure 16 may be employed and adapted to move into three positions instead of only two as described, but, alternatively, a form of lever as shown in Figures 18 and 19 may be 35 employed. In this construction the rod 27 is disposed in the hollow rod 26d as before and is adapted to be turned or partially turned by the lever 32 which is conveniently placed relative to the normal con- 40 trol lever 30. The normal position of the small lever 32 is indicated by the full lines the broken lines indicating the two further positions to which the lever can be moved, one for the upward gear 45 changes and the other for the downward changes. A suitable fixed quadrant may be provided as at 33 to hold the lever in its different positions. The lower end 27a of rod 27 is coupled to the cam 50 with reference to Figures 10 and 13 the normal control of the selector shaft being taken from the end 26f of the hollow rod 26d. Lever 30 is of flexible construction as in Figure 16. 55 Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare that what I claim is:— 60 1. In a change-speed gear control of the kind in which a rotatable pre-selector member is employed to pre-select a gear and to permit the gear engaging means to become operative when a control member 65 is depressed or moved for this purpose, the combination with the pre-selector member of means by which the movement of the control member in one direction effects a partial turn of the pre-selector 70 member to select the next gear in the sequence and the return movement of the control member in its other direction effects the engagement of the gear so selected. 75 2. In a change-speed gear control, as in Claim 1, forming or providing a toothed member by which the pre-selector member is normally turned with a plurality of ratchet teeth adapted to be 80 engaged by a pawl or arm actuated by a shaft or equivalent member that is linked or coupled to the control member. 3. In a change-speed gear control, as in Claim 2, the combination with the pawl 85 or equivalent adapted to engage ratchet teeth on the pre-selector member, or to engage ratchet teeth on a toothed member that is normally employed to turn the pre-selector member, of means for making the 90 said pawl or equivalent operative or in-operative as desired. 4. In a change-speed gear control, as in Claim 1, forming or providing the pre-selector member, or a toothed member by 95 which the pre-selector member is normally turned, with two sets of ratchet teeth adapted to be engaged by two pawls or arms actuated by the control member so arranged that the pre-selector member 100 may be turned in one direction to select upward gear changes and turned in the other direction to select downward gear changes. 5. In a change-speed gear control, as 105 in Claim 4, a construction in which two pawls or arms are pivoted on an actuating member one pawl or arm adapted to turn the toothed member and through it the pre-selector member to select upward gear 110 changes and the other pawl or arm adapted to turn the toothed member in the opposite direction to select downward gear changes and a cam member by which either pawl or arm may be made opera- 115 tive or both pawls or arms be made in-operative. 6. In a change-speed gear control, as in Claim 1, a construction in which an actuating shaft or equivalent member 120 moved by the control member is linked or coupled to a pawl carrier loosely mounted on the pre-selector member as a means of turning the pre-selector member and the provision of a cam member by which the 125 pawl may be made operative or inoperative. 7. In a change-speed gear control, as in Claim 2, the combination with the pawl or arm of a cam member adapted to make 130 the pawl or arm operative or inoperative | ||