Taking out the Bumps
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By R. D. CATER
AT a demonstration on the Fighting Vehicle Research and Development Establishment test track last week. I witnessed and experienced the results of fitting the Bostrom Viking suspension scat into a vehicle.
To drive any type of commercial vehicle empty for long distances is. to say the least. fatiguing. The attendant dangers of fatigue arc perhaps not so well known; for instance, there is a marked deterioration of vision when a person is subjected to vibrations and movements at the rate of 5 to 90 cycles per second and physical reaction time is seriously affected by exposure to vibrations below 20 cycles per sec. These results have been obtained from laboratory tests which have also shown that mental condition and tracking ability are affected.
The Viking suspension seat is so effective that I found it possible to drive an empty four-wheei-drive 1-ton truck at speeds of up to 35 m.p.h. around the fighting vehicle test track in almost absolute comfort, whilst my companions who were seated on the normal passenger scat—were -alternately tossed back and fourth between seat. and roof in such a manner that two circuits of the course Was all.they were prepared to undertake.
Springing of the seat unit is by a multileaf torsion-bar which can simply and quickly be adjusted to accommodate a driver of any weight when, together with the double-acting hydraulic shock
absorber—which is rubber mounted to further absorb shocks that may be caused by a mechanical joint at this point—provides a second suspension medium between driver and axles.
Generarseat design is of a very high order, and one gets an immediate feeling of long-range comfort without the need to fidget about whilst getting corn
fortable. Designed to fit into the often small spaces allowed by the British forward-control type of driving-cab it is hoped that many of the leading makers will offer the seat as an optional extra when, it is thought, it will cost approximately £35-40.
On a demonstration machine, where the seat was fitted alongside a standard fixed unit on a platform which was raised and lowered 3 in. three times per sec., it was quite possible to read standard-size print without difficulty while sitting on the Viking seat. But to sit on the fixed unit required most of one's concentration just to stay put.
It is claimed that the seat will insulate the driver from about 80 per cent of the road shocks that would be transmitted by ordinary seating. Personally I feel that the unit would be a great advantage fitted in some of the smaller artics and, of course, on vehicles that operate off the road.