Patent GB-561685-A (GB)
Title: Improvements in or relating to steering mechanism for motor vehicles
IPC: B62D7/00
Filed: 1942-11-17
Abstract: 561,685. Motor vehicle steering gear. DAIMLER CO., Ltd., and BLAGDEN, W. M. Nov. 17, 1942, No. 629/43. Divided out of 7118/41. [Class 79 (v)] Means for steering all four wheels of a vehicle by a single steering member which can be made to act at will either upon the front and rear wheels in succession in forward travel or upon the rear wheels only in rearward travel, the wheels not being steered being automatically locked, is characterised by a differential or rotary mechanism coupled to the rotating shaft driven by the steering hand wheel and also adapted to be coupled to rotating shafts driving the front and rear steering gears respectively to effect the progressive steering of the front and rear wheels or the steering of the rear wheels, according to the direction in which the vehicle is geared to travel. In the construction shown, the steering hand wheel shaft 5 drives through bevel gear 8, 7 a shaft 6 carrying the planet carrier 1 of a bevel gear differential, the sun pinions 3, 4 of which gear with the planet pinions 2 carried by the carrier 1. The sun pinion 3 is connected by a shaft 11 to a steering gear-box 12 steering the front wheels 13 through linkage 14, 15, and the sun pinion 4 is connected by a sleeve 16, bevel gears 17, 18, shafts 19, 20 to a steering gear-box steering the rear wheels through linkage similar to the linkage 14, 15. One or other of the bevel pinions 3 or , 4 is always locked by means controlled by a slidable and part-rotatable shaft 27 actuated through a spring connection 43 ... 46 by the .reversing lever 36 of the vehicle transmission 38. The locking means comprise escapement wheels 3a, 4a fixed respectively to the sun pinions 3, 4, and each formed, with a notch 24 or 24a, adapted to be engaged either by a single tooth 25 or 25a formed on each of two escapement pinions 26; 26a fixed on the slidable and rocking shaft 27 or by one of two teeth25b on the pinion 26, the tooth 25 being in the plane GH, Fig. 3, and the teeth 25b being in the plane GH. The shaft 27 also carries a gear 28 having three notches 29 adapted to be engaged by a spring-loaded pawl 30 so as to lock the shaft 27 in any one of three positions. In the position shown in Figs. 3 and 5, in which the reversing lever 36 is set for forward travel, the single tooth 25a on the pinion 26a engages the notch 24a in wheel, 4a and the rear steering gear is locked. The tooth 25 on the pinion 26 is clear of the wheel 3a and the two teeth 25b on this pinion although in line with the wheel 3a stand one on each side of the notch 24 so that the wheel 3a and the front steering gear'are free. Rotation of the steering shaft 5 thus steers the front wheels only until they are at full lock ; by this time a roller 32 carried by an arm 31. on the planet carrier 1 will have rotated through 180. degrees and will have engaged a cam surface 34 on the pawl 30 to lift the latter clear of the notches 29 leaving the shaft 27 and therefore the escapement wheels 26a, 4a free to rotate. The continued rotation of the steering shaft 5 now acts on the sun pinion 4 to rotate the wheels 4a, 26a so that the tooth.25a, on 26a leaves the notch 24a on 4a ; simultaneously, the pinion 26, fixed with pinion 26a to shaft 27, rotates until one of its spaced teeth 25b engages the notch 24 in wheel 3a, and further, the roller 32 releases the pawl 30 so that it drops into the next notch 29 and locks the shaft 27, the wheel 3a and the front steering gear. The rear wheels are now steered, the front wheels remaining at full lock. Reverse rotation 'of the steering shaft 5 first returns the rear wheels to the straight-ahead position and then the front wheels: When the reversing lever 36 is moved to the forward travel position the shaft 27 is slid to the right from the position shown in Fig. 3, so that the tooth 25 on pinion 26 is slid into the notch 24 in wheel 3a and locks the front steering 'gear, while the tooth 25a on pinion 26a slides out of the notch 24a in wheel 4a and leaves the rear steering gear free to be operated by the steering shaft 5. At the same time a hole 47 in the pinion 26 is engaged by a fixed pin 48 and the pinion 26 and with it the wheel 3a positively locked no matter through what angle the steering shaft 5 is turned. The spring connection 43 ... 46 between the reversing lever and the shaft 27 allows the reversing lever to be moved at any time whatever the position of the steering wheels, the shaft 27 being then spring-loaded but not moving axially to change the locking mechanism until the steering wheels are in the straight-ahead position.