Patent GB-308959-A (GB)
Title: Improvements in or relating to testing apparatus for motor vehicles
IPC: G01L5/28
Filed: 1927-12-30
Abstract: 308,959. Welch, W. H. Dec. 30, 1927. Dynamometers; systems for testing motor vehicles.-Comprises a portable apparatus for testing the braking power including a pair of rollers for supporting a wheel, a manually rotatable shaft, driving means between the shaft and one or both rollers, and means for measuring the torque applied to the rollers. A trough 20 has a pair of roughened rollers 21, 22 shaped to conform to the tyre of the wheel which rests upon them. On one side of the trough is a triangular casing formed in two parts into which extend the spindles of each roller, each spindle being fitted with a sprocket wheel around which passes a sprocket chain which also passes over a sprocket 32 on a shaft 31 mounted at the apex of the casing. The spindle 31 drives the sprocket 32 by means of a reduction gear 34, 35, 37, 38, the spindle 36 of the wheels 35, 38 being carried by arms 39, 40 of which the latter is extended downwards and provided with laterally projecting arms 41, 42 adapted to engage the shorter arms of horizontal bell-cranks like 43, 44 (Fig. 5), the other arms of which bear on the diaphragm 51 of a chamber filled with oil. In use the wheel of a vehicle is run on to the rollers and a drive imparted to them by turning the handle. If now, the brakes are applied. the wheels 35, 37 move epicyclically and the diaphragm chamber is compressed to a degree which is a measure of the braking effort and is indicated on the gauge 53. In another form a conical spiral spring 59 of rectangular section material is substituted for the diaphragm chamber, the bell-cranks 43, 44 being vertical and the movement of the spring being transmitted to a pointer by rack and pinion 61, 62. In this form means are described for measuring the load on the wheel. A lever 66 pivoted at one end 67 to the trough passes into the gearbox and engages with its free end under one arm of a bell crank 69, the other arm of which carries a knife-edge 70 engaging the projection 40. The lever 66 is provided in the centre with a pointed plunger 75 adapted to pass through the base of the trough. The plunger is lowered by turning the nut 74 with a tommy bar until it rests on the ground and on further turning the nut, the load is transmitted to the spring 59 and indicated on the same dial as the torque, further rotation of the nut only causing the whole apparatus to turn about the edge 77. The shaft 31 may be provided with a clutch and a self-contained worm gear fitted which may be driven by a motor. If it is desired to measure the power to drive the vehicle the engine of the vehicle is allowed to drive the rollers and a dynamometric brake is fitted to the spindle 41. In another form the wheel-supporting rollers are carried by a member adapted to slide against the influence of a spring. The shaft 31 drives through a reduction gear and the movement of the member carrying the rollers is transmitted by rack and pinion to a dial. Each roller may be fitted with a ratchet drive so that the wheels of the vehicle are pushed up against the rollers which then lift the vehicle. A ramp may be fitted at each side of the frame of the device to enable the vehicle to be driven on to it.