GB1372064A - Wheel alignment gauge - Google Patents

Abstract

1372064 Measuring wheel alignment electrically V L CHURCHILL & CO Ltd 16 Jan 1973 [16 Oct 1971] 9614/71 Heading G1N Apparatus for measuring the angular inclinations of the wheels of a road vehicle comprises a block 1 Fig.1 which is mounted on each front wheel, with a reference face perpendicular to the axis of rotation, and carrying two mutually perpendicular inclinometers which measure wheel camber and King-pin inclination. As shown in Fig.4, the two inclinometers consist of three inter-connected vertical bores in block 1 containing oil, forming two perpendicular U-tubes, the height of the oil in each bore being measured by a capacitive transducer 12. The differences in height indicate the angle of inclination of each wheel in each of two perpendicular planes, representing the camber and King-pin inclination of each wheel. The capacitive transducers 12 determine the frequency of a multi-vibrator, which is converted to a proportional current. Each block 1 is also connected by a tube 2 to a further block 3 carrying a rotary capacitive transducer for measuring angular displacement of a spindle 4. The spindles are maintained aligned by a bar 9 located in V-blocks,5, or by a spring tensioning arrangement, and each transducer measures the angle between the tube 2 and the bar 9. The difference between the sum of the measured angles and 180 degrees is the toe-in or toe-out of the wheels, and is measured by the multi-vibrators referred to above, whose outputs may be fed to a loud speaker after the circuitry has been adjusted to give zero frequency output when the wheels are set to a desired toe-in.