Patent GB-673608-A (GB)
Title: Improvements in or relating to automotive road vehicles
IPC: B62D21/18
Filed: 1950-09-05
Abstract: 673,608. Single track vehicles; steering motor vehicles. BANCROFT, C. Sept. 5, 1950 [Sept. 15, 1949; July 29, 1950], No. 21842/50. Classes 79(v) and 136(iii) [Also in Group XXXII] A vehicle includes a frame, front and rear single wheels supporting the frame and pivotally connected therewith, at least one middle wheel between the front and rear wheels and means connecting the middle wheel with the frame to permit lateral shifting of the middle wheel and tilting of the frame in response to the lateral shifting. In the arrangement according to Figs. 1, 3, 4 and 6, a main frame including an upstanding arch 1 supports front and rear frames 2 and 3 having wheel supporting forks 5 and 6 respectively. Front and rear wheels 8 and 9 which are both steerable and are arranged on the longitudinal centre line of the vehicle, are mounted to provide a castor action. Side structures 14 support the vehicle body. A sub-frame including spaced bars 15, 16 and a frame 18 which may be integral therewith carries longitudinally extending horns 17 for leaf springs 19 mounting an axle for a pair of wheels 21, 21. The axle may be driven in known manner through a differential and drive shaft 23. The main frame and sub-frame are interconnected through a lever system comprising plates 24, Fig. 4, which are pivotally connected to the bars 15, 16 and carry bars 28. The rear ends of the bars 28 are interconnected through bell cranks 29, Fig. 1, and a link 30 and are pivotally connected to the main frame through links 31. The front ends of the bars 28 are pivotally connected to the main frame through levers 33, links 34 and a common pivot 35 on the frame 2. The bars 28 are also connected through links 37 with the rear end of the frame 2. Lateral shifting of the sub-frame relative to the main frame may be effected manually or automatically. Steering is effected through a worm and sector gear 41, Fig. 3, and arms 44, 45 and 47, Fig. 6. The arm 45 which is pivotally connected to the main frame is also connected through an arm 48, link 19, lever 50, link 52, lever arm 53, link 54 and shaft 56, to a lever system 57. 58. 59 and 60 for steering the rear wheel 9 The forward end of shaft 56, provides a fixed pivot 51 for the lever 50. A pivot pin 61 for the lever 53 is mounted on a lever 62 which is rotatable by means of a shaft 63 and arm 64 to effect differential steering of the front and rear wheels. The arm 64 is connected through a link 65 and a lever 67 to a section 41a of a steering column housing 41, so that tilting of a steering wheel 39 without rotation thereof effects steering of the rear wheel 9 only, while rotation only of the wheel 39 effects equal steering of both wheels 8 and 9. Self steering tendency of the rear wheel, due to uneven weight distribution on the 'vehicle, is overcome by means of a manually operated adjustable spring bias which is applied to the link 65 through gearing 73. Shock absorbers 77, Fig. 4, may be provided between the main and sub-frames. In another arrangement, Fig. 7, in which a main frame 81 supports front and rear steerable wheels 88 and 89, a sub-frame 92 carrying a centre wheel 93 is rotatably and slidably mounted on a shaft 90 and carries at its rear end an engine 95 in driving connection with the wheel 93. Compression springs 97 may be arranged between a frame member 98 and the sub-frame 92. A steering wheel 100 is arranged for rotation and rocking transversely of the vehicle. Rotation only of the wheel 100 effects equal and opposite steering of the wheels 88, 89, while differential steering of the latter is effected by means of a rod 113 movement of which, due to rocking of the steering wheel, displaces, forwardly or rearwardly, the pivot point of a lever 107, interconnecting steering rods 106 and 108 and 110 for the front and rear wheels respectively. An additional power operated automatically controlled device may be used to effect the lateral movements of the wheel 93. The vehicle may be provided with retractible wheels or skids.