All set at Hendon
Page 31
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Over the pit the vehicle will get a thorough mechanical examination (stations will have the right to refuse vehicles too dirty for reasonable examination, though this will not necessarily mean prior steam-cleaning) and the front axle will be raised to permit steering and king-pin checks. The jack used for this at Hendon is a German 5 /6-ton electro-hydraulic model which is not only quick and simple to operate but narrow enough not to obstruct the pit.
A lightweight intercom set provides communication between the man in the cab and the man in the pit; vehicle exhaust gas is carried away by flexible pipes feeding into a long duct on the floor.
From the pits the vehicle will be driven forward to station three, where headlights will be checked for intensity and setting, then forward again to the brake tester. This will be a roller tester of familiar type, the actual example at Hendon being a Triangle. This has rollers of the standard European size (190 mm. diameter—about 7.5 in.) and these drive the vehicle's wheels at the standard test speed of 2 k.p.h. As the brakes are applied with steadily increasing pressure, so dials register the braking force in lb., and also show immediately if there is lack of balance between the braking effort on each side. Maximum braking force is reached as the wheels stop, this being the figure on which the pass /fail braking efficiency will be based.
Although the rollers have a high-friction surface there can still be some slip between tyre and roller. Its effects are so small that the friction roller has proved acceptable (and is also speedy and simple to use, as well as being reasonably priced) for the Ministry test stations.
But at Hendon, where experimental work is still going on, one trial rig is an electrically powered brake tester that overcomes the slip problem by driving the wheels through lugs over the wheelstuds. This is slower and more clumsy than the roller system, since the adaptors have to be changed to suit different wheels—though about four adaptors will cover all UK goods vehicles.
Another piece of experimental equipment is a load simulator, for possible use where empty vehicles have to be tried under loaded conditions. Not experimental in itself, but being tried at Hendon, is a Fairlift extending-jib crane that can lift a 1-ton test weight, place it in the interior of, say, a boxvan, and then later withdraw the test block and lower it to the ground.
One of the key aims of the experiments at Hendon is a procedure for the quickest and easiest test routine. It is intended that the central booking office will arrange for similar categories of vehicle to come through in batches, and examiners on the test line will have a standard inspection card, with numbered items, to follow. Since it is a flow line layout, the jobs at each station have to be as near equal in time as possible.
What will the inspectors be looking for? Well, the legislation at present refers only to selected Construction and Use features. But it can be taken that the list of items to be checked will not be far removed from the current "GV9" practice followed by Ministry area examiners—though possibly more thorough in view of the better facilities.
The plating—which will be legally enforceable once done by the Ministry men—will be undertaken against a standard list that is now being drawn up for all makes, models and recognized conversions.