Patent GB-644942-A (GB)
Title: Improvements in or relating to vehicle change-speed transmissions
Inventor: HENDERSON CYRIL
IPC: F16H63/30
Filed: 1948-04-23
Abstract: 644,942. Change-speed control. ROLLS-ROYCE, Ltd. April 23, 1948, No. 11272. [Class 80(ii)] A gate-guided selector-control for the three (or more) three-position shift-rails 27, 28; 29 (or double-armed levers) of a five (or more) speed and reverse gear, permitting straightthrough shifts between the two lowest and the two highest speeds, comprises one or more rocking-spiders 33 having three radial arms 33a, two of which fulcrum on two idle shiftrails whilst the third moves the selected shift-rail in either direction from neutral when the spider 33 is rocked endwise by axial movement of an actuator-bar 32, caused by fore-and-aft movement of a shift-lever (not shown) in a gate, Fig. 1, the two idle shift-rails being selectively locked in neutral by recesses 34b, 34c and a lug 34a en a slidable (or rotatable) latch-bar 34, Fig. 6, which is moved axially through an arm 35 by turning movement of the actuator bar 32 caused by the cross-shift movement of the shiftlever in the gate-slot 12. The rocking- spider 33 may be mounted on the actuatorbar 32, with the shift-rails 27, 29 grouped around it, but, as shown, the spider has a fourth radial arm 33a through which it is rocked by the actuator-bar 32. Initially with the shift lever in the operative end of the gate notch 14, the shift-rail 29 is engaging first speed, and in this plane, the latch-bar lug 34a overlies a flat 29b, Fig. 8, on one side of the rail 29 permitting its movement between first-speed and neutral only; the fourth-fifth shift-rail 28 is locked in neutral by the latch-bar recess 34c; whilst the one side of the latch-bar recess 34b overlies a recess 41, Fig. 9B, in the adjacent side of the second-third shift-rail 27, so that the latter would be free to move between second-speed and neutral positions. only, apart from the provision of adrift-pin interlock, Fig. 5 (not shown), between the rails 27, 29. Shift to second-speed is accomplished by a straight-through movement from gate-notch 14 to 13, maintaining the lever in the plane of the former. The spider 33 at first fulcrums on the locked rails 27, 29 but when the neutral position is reached, an abutment 37, Fig. 8, on the first-second shift-rail 29 is arrested by the latch-bar lug 34, and in this position the drift-pin interlock frees the shift-rail 27. Continued movement of the shift lever then causes the spider 33 to fulcrum on the locked, rails 28, 29, moving the rail 27 in the opposite direction to that of the rail 29 to establish second speed in the notch 13. In this position the shift-lever can be moved laterally in the widened notch 13 to come opposite the third speed notch 15, this movement serving wholly to free the second-third rail 27 for movement in either direction and also wholly locking the firstreverse rail 29 by the latch-bar lug 34a - confronting abutments 36, 37, Fig. 8, on opposite sides of the rail 29. The shiftlever may now be moved straight through to the notch 15 engaging third-speed by movement of the rail 27. Movement of the lever through the gate-slot 12 into the plane of the notches 16, 17 causes the latch-bar 34 to free the shift-rail 28 whilst wholly locking 27 and 29, so that the spider 33 can fulcrum on them in moving the rail 28 to establish fourth speed in notch 16 and fifth by a straight-through movement into notch 17. In gate-notch 18, the lever causes the latch-bar 34 to lock the rails 27, 28 in neutral and the latch-bar lug 34a overlies a flat 29a on the opposite side of the rail 29 which can thus be moved between neutral and reverse only. The shift-rails 27, 29 have spring ball-detents 47 for locating them in gear and neutral positions and a spring plunger 52 opposes movement of the latchbar 34 correspondingly to movement of the shift-lever into the end-gate notches 14, 18 for first speed and reverse.