Patent GB-206876-A (GB)
Title: Improvements in liquid fuel consumption and distance indicators or registers for motor vehicles
IPC: G01F9/00
Filed: 1922-05-16
Abstract: 206,876. Higginson, J. May 16. 1922. Measuring consumption of petrol with respect to speed of motors; differential and average speed indicators.-Apparatus for indicating the average distance travelled by a motor vehicle per unit quantity of fuel consumed comprises two logarithmic cams rotated in opposite directions respectively by the means for feeding fuel in measured quantities, and bv means actuated in accordance with the distance travelled. The cams may be connected through spicyclic gearing to an indicating-hand 12, Fig. 2, movable over a fixed scale graduated logarithmically, or through other means, to a movable hand 12 and a movable dial 49, Figs. 8 and 18, associated with a fixed annular dial. The fuel may be drawn from a reservoir by a vacuum feed tank, such as is described in Specifications 12835/11, 20191/14, 11992/15, 138,400, and 153,662, the pulsations of pressure in the tank being transmitted to a diaphragm chamber g, Fig. 4. The diaphragm is connected to ar. arm i pivoted in a bracket k and carrying pawls m, m<1>, engaging a ratchet wheel o, which is rotated by one step at each movement of the diaphragm. The movement of the wheel o is communicated through worm wearing r, s to the fuel-consumption cam t. The distance cam x is driven through worm gearing v, w from the usual flexible shaft of the odometer. Arms y, 2, Fig. 6, with knife-edged projections z, 3, resting on the cams t, x, are connected to and move sun gears 4, 5 of a differential mechanism, the planet pinion 7 of which is mounted on an arm 8 of a shaft 6 carrying a quadrant 9 gearing with a pinion 10 on the pointer shaft 11. The cams may have circular inner portions 13, 14, Fig. 6, corresponding with the distance travelled for the first unit of fuel consumed, or the driving- means may have a lost-motion connection to delay indication until the end of the initial period. The shaft of the worm e of the fuel measuring device is adapted to drive total and trip registers 22, 23, Fig. 3, for the quantity of fuel consumed, and' similar distance registers 25, 26 are driven from the shaft u. The trip registers may be zeroized and the cams also turned to zero position bv sliding and turning shafts 24, 33. If the performance of the vehicle in terms of distance per unit of fuel is already known, the circular parts of the cams or the lostmotion drive may be omitted. The trip distance and fuel registers are then set manually to the assumed distance per unit of fuel and to one unit of fuel respectively to position the cams correspondingly, the instrument being ready to indicate the actual performance as soon as the test commences. In the arrangement shown in Figs. 8, 10 and 11, a geometrical spiral cam 40 is connected through a volute spring 42 with the fuel cam t, and a similar cam 41 is connected with the distance cam x. Spring-pressed pallets 44, 45, bear each on two associated cams. The cams x and 41 actuate the pointer 12, and the cams t and 40 actuate the movable dial 49. The fixed outer scale is graduated in distances, the distance run being indicated by the pointer 12. The movable scale is graduated to read opposite the pointer 12 the distance per unit of fuel, the pointer preferably being transparent while the quantity of fuel is read against a fixed intermediate scale by a pointer or mark 51 carried by the movable scale. In the further arrangement, shown in Figs. 18, 19, a toothed sector 55, with a knife-edged projection z resting on the cam t gears with a pinion to rotate the finger 12, while a similar sector gears with a pinion 60 to rotate a dial 49, the instrument having also fixed scales as described with reference to Fig. 8. According to the Provisional Specifications the resetting may be effected by the provision of a cradle-like member holding the worms actuating the cams, and means operated by hand or automatically for moving the cradle to disengage the worms and allow the cams and movable scales to be reset by springs.