Testing the Brakes of Six-wheelers
Page 74
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TiE Bendix-Cowdrey four-wheel brake testers manufactured by Bendix. Ltd., Tyseley, Birmingham, have achieved such success that the company has now introduced a similar equipment capable of testing the brakes of six wheels simultaneously, and our illustration shows a Leyland trolleybus, owned by Birmingham, mounted on the new equipment, which is known as the 67A/43.
The time taken to test the six wheels of such a vehicle, including driving on to and off the machine, is about three minutes. This, of course, does not allow for any adjustment which may be necessary, but it will give the observer a definite comparison of the braking effort between the respective wheels. One of the largest transport concerns has stated that the use of the new tester reduces the time taken for the adjustment of brakes' on a heavy vehicle from over two hours to about 20 minutes.
The vehicle which it is desired to examine for braking efficiency is run into position over a special pit and allowed to rest with its six wheels seated on steel rollers, the surface. of which is treated with composition to prevent tyre slip due to wet or oil. The
rollers are set in motion by electric motors, and the driver of the vehicle, which is anchored in its position by a heavy chain, receives instructions froth an official in the pit through the medium of an indicator which is facing him ; this obviates any misunderstanding which may be caused through shouting instructions from the pit. The man in the pit can then tell from the dials exactly the proportion of braking upon each of the six wheels as he signals to the driver to release or apply the respective brakes. He can also readily distinguish whether there be any drag inside the brake drums when the braking action is withdrawn.
The braking effort is measured in terms of pounds of road pull and obviates the need for a road test after adjustment. The factors are, of course, constant, consideration does not have to be given to gradients, dampness, or variations of surfaces.
Such an equipment as this is a definite factor in the promotion of safety on the road. The speed at which tests can be carried out enables them to be made more frequently and to a certain standard of efficiency. This is a particularly important point in the case of public service passenger vehicles which may he driven by different men daily or even twice daily.
Further particulars of this equipment or of the types for vehicles of medium capacity can be obtained from Bendix, Ltd., Tyseley, Birmingham, or The Equipment and Engineering Co., Ltd., 2 and 3, Norfolk Street, Strand, London, W.C.2.