GB1469592A - Wheel balancers - Google Patents

Abstract

1469592 Detecting vehicle wheel unbalance GKN TRANSMISSIONS Ltd 30 June 1975 [3 July 1974] 29406/74 Heading G1N and G1X The balance of a wheel is tested whilst on a vehicle by means of apparatus comprising a platform on to which the vehicle is driven, jacking means for raising the vehicle, elevatable roller means for engaging the wheel to be tested, motor means for driving the roller means and hence rotate the wheel, means for sensing a rotational out of balance condition and developing a signal in response thereto, and display means responsive to the signal to indicate the condition. The roller means comprises two elevatable rollers 18a, 18b each having associated therewith a respective fixed rotatable roller 19a, 19b, each roller pair 18a, 19a and 18b, 19b forming a cradle for a respective vehicle wheel. Each elevatable roller 18a, 18b is mounted on an elevator member 20a which supports a respective drive member 25a. As described each member 20b is raised by a respective hydraulic ram or piston and cylinder unit 28a and the jacking means comprises an arm 36 having pads 37a, 37b supported from telescopically adjustable bars 38a, 38b, the arm 36 being raised by a jacking ram 40. Rams 40, 28a are connected in a pressure fluid circuit Fig. 5 (not shown) including a pump (41a) and valve means to control the supply of the fluid to the rams. Interlock means prevents raising of the rollers 18a, 18b until fluid-flow has been established to raise the jacking arm 36 and lowering of the arm 36 until the rollers 18a, 18b have been lowered. The sensing means comprises a vibration transducer TDI on a magnetic base 43 which is mounted adjacent the wheel on the chassis. A resulting signal after amplification is rectified and compared with a reference voltage which sets the level of a "pass" or "fail" condition. A voltage is applied to a circuit 49 a pre-set time, as determined by switch 51, after motor 25a or 25b for rollers 18a, 18b respectively has been brought up to full speed, causing a relay RL to be or remain de-energized according to whether the unbalance condition is too severe or not. Relay RL has contacts for energizing "pass" indicator 52, e.g. lamp, "pass" print out device 53 and similar fail indicator 54 and print out device 55. The magnitude of unbalance, rather than a mere "pass" or "fail" indication may be obtained by using in addition a stroboscopic lamp controlled by the output of the transducer TDI to illuminate the wheel under test appropriately marked at its circumference. Measurement of the magnitude of the out of balance signal at the output of amplifier 46 provides data as to the magnitude of a counterbalance weight to be applied, the position thereof being determined by that occupied by the stroboscopically illuminated mark.