Almost Too Good
Page 30
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rinHE great improvement in brakes which has I occurred in recent years has emphasized the danger of shifting loads. Unfortunately, the tendency, stimulated by artificial weight restrictions and an ever-growing need for operating economy, has been towards the construction of flimsier bodywork. The rear panel of the average cab offers little, protection against a heavy load violently propelled and headboards are often far too light in construction to withstand a severe shock.
This is a matter to which operators should give careful thought when ordering bodywork. Members of the staff of The Commercial Motor have on several occasions narrowly escaped serious injury when loads have shifted during brake tests. The primary fault was in securing the test loads, but bodywork should be sufficiently stout to protect crews against the results of human error.
• Special tare is necessary in stowing goods in vans which have no rear bulkhead behind the driver. In at least one instance a mad spoiled a long record of freedom from accident when, in braking, he was struck on the side of the head by his load. The result was a collision With a bus.
Over-sensitive air brakes with extremely light pedal actions can cause braking in an emergency, particularly with unladen vehicles, to become dangerously fierce. This possibility has been recognized by manufacturers, who have fitted reaction springs in brake valves to increase pedal resistance. Vacuum brakes on medium-weight vehicles can also reach a degree of efficiency which requires drivers to treat them with great discretion.
Some American manufacturers provide a valve by means of which, on a wet road, the driver of an articulated ontfit may isolate the front brakes to prevent the possibility of a front-wheel skid.
Brake makers are constantly striving for higher efficiency, but operators and bodybuilders must recognize the stresses imposed by powerful braking. Bodywork must be adequate to deal with them, and drivers and loaders must be properly instructed in the art of securing the wide diversity of loads that many vans and lorries have to carry.