Patent GB-604436-A (GB)
Title: Improvements in or relating to automobile power transmission
IPC: B60W30/18
Filed: 1945-01-03
Abstract: 604,436. Controlling change-speed gears and clutches. TRIGGS, W. W. (Timken-Detroit Axle Co.). Jan. 3, 1945, No. 275. [Class 80 (ii)] [Also in Groups XXVII, XXXI and XXXV] A two-engined motor vehicle has a two-speed drive axle driven by one engine and a singlespeed drive axle driven by an auxiliary engine, and control means, whereby the vehicle may be driven either by the one engine driving the two-speed axle at its higher speed, or by the one engine driving the twospeed axle at its lower speed, or by both engines driving their associated axles, the one engine driving its two-speed axle at a speed which is selected by the control means simultaneously with the operating of switch means in the starting circuit of said second engine. The vehicle, Fig. 2, comprises a main engine 26, clutch 28, gear-box 30, propellor shaft 32, and two-speed differential drive 36, driving the rear axle ; also an auxiliary engine 40, clutch 42, gear-box 44, propellor shaft 46 and two-speed differential 50 driving the front axle. The construction of the rear axle two-speed differential and its method of operation is the same as that described in Specification 587,102, the appropriate speed being selected by the manual control 53 and pneumatic power unit 32<1>. The frontaxle drive is disconnected automatically should the auxiliary engine stop, by means of a pneumatic power unit operating a suitable clutch (not shown), and connected by pipes 64 and 148 with the inlet manifold of the auxiliary engine 40. Means are provided for changing gear on the auxiliary engine gearbox 44 in step with changes effected manually on the main gear-box 30, such means including a control valve 72 (see below) interconnected with the main gear lever, conduits 88, 100 and 102, and a servo device 66, 68, 70 (see below) attached to the auxiliary gear-box. A pneumatic auxiliary engine clutch control mechanism 196 (see below) provides for the auxiliary clutch 42 to be connected with the main clutch 28 for simultaneous operation only whilst the auxiliary engine is running. Switching arrangements may be provided (see below) to provide for either manual or automatic starting of the auxiliary engine. Gear changing.-The control valve, 72, Fig. 5, comprises a pair of independently movable plungers 112, shown in section in Fig. 9, and 114, shown in section in Fig. 7, terminating in lugs 116, 118 which are engaged by the main gear-lever. The plunger 114 comprises an axial bore 154 communicating with the radial aperture 152 and the end chamber 144 which communicates via the pipe 148 with the inlet manifold of the auxiliary engine ; plunger 114 also has an annular recess 128 ; port 124 communicates with the atmosphere through filter 126 ; pipe 88 leads to the pneumatic control device, shown in Fig. 3, and described below, for engaging low gear in the auxiliary gear-box. The plunger 112 has an axial bore 142 communicating with radial apertures 140, 161 and with the end chamber which also opens to pipe 148 connected to the auxiliary engine inlet manifold ; the plunger 112 also has annular recesses 162 and 134 ; ports 164 and 132 open to the atmosphere through filter 126 ; pipes 102 and 100 communicate with the pneumatic control device shown in Fig. 3, for selecting second and top gears in the auxiliary gear-box. The plunger positions shown in Figs. 7 and 9 correspond to neutral gear. On engaging 1st gear in the main gear-box, plunger 114 is moved to the left, but such movement does not affect the pneumatic connections and the auxiliary gear-box is unaffected. On engaging 2nd gear in the main gear-box, plunger 114 is moved to the right which puts the pipe 88 into communication with the vacuum pipe 148 and so subjects the valve 66, Fig. 3, to diminished pressure, raises the rod 82 and lever 84 to engage low gear on the auxiliary gear-box. Each of the servo units 66, 68, 70, Fig. 3, comprises a spring loaded diaphragm 76 one side of which can be subjected to reduced pressure to compress the spring 78, and the other of which communicates with atmosphere through openings 79. On engaging 3rd gear in 'the main gear-box the plunger 114 is first restored to the neutral position as in Fig. 7, the plunger 112 is then moved to the left to transmit vacuum to both pipes 100, 102 and so operate both servo units 68, 70, Fig. 3, to rotate the lever 94 clockwise from its neutral horizontal position and so engage intermediate gear in the auxiliary gear-box. On engaging 4th (top) gear in the main gear-box, plunger 112 is moved to the right, whereby pipes 100 and 102 are both put at atmospheric pressure, whereupon the springs in the servo units 68, 70 cause the lever 94 to rotate anti-clockwise and so engage 3rd (top) gear in the auxiliary gear-box. Clutch control.-The mechanism shown in Fig. 12 serves to couple the main engine clutch with the auxiliary engine clutch only when the auxiliary engine is running. On actuation of the main clutch, a rod 174 from the main clutch operating mechanism rotates the shaft 180 mounted in bearing bracket 182. The shaft 180 projects into a bracket 186 secured to the operating shaft 184 of the auxiliary clutch and is freely rotatable in each bracket. The shaft 180 has a notch 194 thereon, such notch being engageable by the rod 190 upon axial movement of the latter so as to lock the two shafts 180, 184 together and so provide simultaneous operation of both clutches. The rod 190 is moved axially by the servo unit 196 when the auxiliary engine is running and the reduced pressure in its inlet manifold is transmitted by pipe 198 to one side of the diaphragm 1941. Electrical system. The auxiliary engine 40, Fig. 14, may be started manually or automatically according to the setting of the master ignition switch 60, which may be set in the neutral position shown to switch-off both engines, or may be set for manual starting or for automatic starting of the auxiliary engine, with either of these two settings the ignition circuit of the main engine is completed. With the switch in the manual position current from the battery 58 goes via line 226 to device 242 (see below), line 234 to the solenoid starter switch 206, contacts 256, 214 of the switch 60 back to the battery ; at the same time the circuit to the auxiliary engine ignition coil 55 is completed, whereby the engine starts. The device 242 in the starting circuit operates to break the circuit when the engine is running, and comprises a pair of normally closed contacts 236, 232 which are opened by movement of the diaphragm 246 when the latter is subjected to sub-atmospheric pressure via pipe 250 from the auxiliary engine inlet manifold. The other side of the diaphragm 246 is subjected to engine oil-pressure via pipe 240 so that once oil pressure has been built up in the engine the device 242 prevents the starter circuit from being completed although the depression in the inlet manifold may be temporarily reduced. With the switch 60 in the automatic starting position the circuit is as before except that contact 256 on the switch is connected to contact 262 and the starting circuit is completed through switch 274, which is closed only when the pneumatic control valve 53, see also Fig. 2, is set to engage the lower ratio in the two-speed differential 34, and through device 266 which as described in Specification 587,102, is connected by two pipes 268, 270 to the main engine inlet manifold and is actuated to complete the electrical circuit only under such conditions that the main engine alone cannot handle the load. The circuit to the main engine ignition coil 220 is completed through contact 216 and either of contacts 222, 224, in either position of the switch.