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).
Page from a patent application describing a change-speed transmission mechanism.
Identifier | ExFiles\Box 136\4\ scan0147 | |
Date | 14th February 1933 guessed | |
2 1,897,851 29 is moved toward the left it carries plate 41 to the left and engages its notch with the pin 55 at the left end of lever 47. When, thereafter, lever 29 is rocked in a longitudi- 5 nal direction, the left end of lever 47 is held from longitudinal movement, and its right end (the pin 55 at that end being released from the notch) is free to move longitudi- nally about its anchored end as a center to 10 shift fork 25. Fork 25 is similarly shifted by a reverse movement of the lever 29. The above construction is a part of a well-known change speed transmission and is not claimed herein. The shifting of the rods 15 shifts clutches and gears in a well-known manner to effect the several driving ratios. The system illustrated may be briefly described. Numeral 59 is a helical gear on the input shaft and is operable to rotate a coun- 20 tershaft (not shown) by meshing with a corresponding gear on the countershaft. At the opposite end of the countershaft another similar gear is to engage and drive a gear 57 which is rotatably mounted on the output 25 shaft 61 adjacent the rear end of the housing. A slidable clutch element 63 is moved by the fork 25. It has a nonrotatable relation with the output shaft 61. It is provided with clutch teeth 67 and 65 to engage clutch 30 teeth 69 on the input shaft and teeth (not shown) on the gear 57. At 71 and 73 are synchronizing clutch elements actuated by the initial movement of the member 63 through the instrumentality of yielding 35 means 75. Slidable but non-rotatable on the periphery of member 63 is a driven gear 77 which is reciprocated by fork 23. This gear is to engage the low speed driving gear and the reverse idler in substantially the usual 40 way. The improvement described in this application relates to a provision for maintaining the clutches (67, 69 for example) in engagement when once meshed until positively re- 45 leased by the action of the shift lever. The rod 21 and the fork 25 are slotted to slidably carry a lock bar 79. Lock bar 79 has a notch 81, the vertical walls 83 and 85 of which are dimensioned to snugly fit the 50 end of lever 47. It will be observed that the space between the lugs 51 and 53 is somewhat in excess of the space between the walls 83 and 85 so that there may be a slidable movement of 79 prior to the move- 55 ment of fork 25 and the rod 21. In the housing there is provided an opening in which is located a ball 87 actuated by a spring 89 to engage recesses 91 in the rod 21, these recesses corresponding to the sev- 60 eral positions of adjustment of the rod and fork. In addition to this detent provision the rod 21 has notches 93 and 95 provided with straight sided walls. The lock bar has notches 97 and 99 formed with curved walls 65 as shown in Fig. 3 to Fig. 5. These notches are so located that in the neutral position of the fork 25 as shown in Fig. 2 the adjacent ends of the walls of notches 97 and 99 coincide with the adjacent ends of the 70 notches 93 and 95. The notches 97 and 99 are, however, of greater length and their remote ends lie beyond the remote ends of the notches 93 and 95. Within the housing is a plunger 101 actuated by a spring 103. 75 This plunger may be located out of the several notches as in Fig. 2 or it may enter the one or the other of the notches as shown, for example, in Fig. 4. Fig. 4 shows the plunger deeply seated in notch 93. Since 80 the notch 93 has straight walls the plunger locks the rod 21 and the fork 25 from reciprocation unless external means is employed to raise the plunger against the tension of the spring. 85 Fig. 2 illustrates the parts in their neutral position. If lever end 47 is moved to the right in this figure the lock bar is first moved since it is engaged by lever 47 and since there is a clearance between 47 and 90 the wall 53 which must be overcome. In so moving the lock bar the notch 97 is made to register with notch 93 so that the mid portions of the notches coincide. At that time the lever 47 picks up the wall 53 of 95 the fork 25 and both rod 21 with the fork and the lock bar move together until the pin 101 is forced into notch 93, this being permitted by the relative position of the notches as explained above. If now a re- 100 verse shift toward the other position is made the first action is to shift lock bar 79 to the left before rod 21 is picked up. In doing so the angular wall 97 pushes the plunger 101 up out of the notch 93. By the time the 105 plunger 101 is wholly removed from the notch 93, both the rod 21 and the lock bar 79 move together. In the movement described notches 95 and 99 have been brought into registration so that the plunger 101 110 may enter notch 95 and lock the shift fork and bar 21 in its new position of adjustment. The above arrangement prevents any unintended disengagement of the clutches. Release is at once effected by the movement 115 of the shift lever in the usual way. Fig. 6 shows a second embodiment of the invention. It is used with similar transmission parts which are, therefore, similarly indicated. Lever 47 of the first form is 120 modified and is represented as 47'. It is provided with an end 105 located beyond the rod 21'. This extremity 105 is snugly received in a recess 107 of the lock bar 79'. The walls 109 and 111 upstanding from the 125 fork 25' are spaced to an extent greater than the walls of the opening 107 so that the lock bar 79' is moved to a limited extent before the fork and rod 21' are moved. Between the guide channels 113 and 115 in the 130 casing for the rod and lock bar, the housing | ||