Demonstrating a "Striking" Safety Bumper
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QOME four years
ago we witnessed experiments with a life-saving , device consisting of a bumper mounted across the front of a vehicle and So arranged that, when it wa.s touched, it immediately rotated in such a way as to roll objects in front of it away from the vehicle instead of forcing its way over them.
Great improvements have been made in this device. There are now two horizontal rollers, one above the'other a n d extended farther to the sides, the two being connected by enclosed gearing so that they rotate in the same direction. Between the rotating members, in a stationary tube, is the driving shaft, connected through bevels to a flexible drive from an electric motor on the chassis frame.
• The bumper is mounted on pivots attached to the front axle, the overhung weight and stresses being resisted by torque members between the axle and chassis.
A leaf spring behind the bumper lessens shocks when the bumper strikes an object. • At each side is a dashpot switch, and, immediately the bumper is forced back slightly, current from the vehicle battery passes to the actuating motor and rotates the rollers at 600 f.p.m.
To improve protection and prevent damage at kerbs, the rollers are given parallel motion across the front of the vehicle by the steering, the maximum effort required for full lockbeing 10 ft.-lb. Additionally', the bumper can be raised a few inehei above the narmal 2-in. clearance by means, of •a leer in th driver's cab. To pre-Vent the def vice from being unintentionally re
tamed in this position when running is normal, the bumper is automatically dropped when the driver changes to a higher gear.
After the rollers have oeen brought into operation they can be stopped by a switch mounted close to the driver, but the dashpot switches are automatically reset ready for further use. The complete Safety Bumper for a vehicle of average size weighs 50 lb. without the motor, and arrangements have been made whereby the ordinary starter motor of a vehicle can he employed, but this could only be done on a production scale. The total cost would then be about £7, and for a private car RS.
Demonstrations with the device were given by Safety Bumpers, Ltd., 15, Prince's Row, London, S.W.1, at the Greyhound Stadium, White City, on Thursday, July 11, and they were most convincing. • A 16-stone man threw himself repeatedly in front of a. lorry travelling at speeds up to 12 mph. and was thrown down and rolled in front of the vehicle for many yards. He then lay directly in the path of the vehicle, nonchalantly smoking a cigarette and, being hit at about 10 m.p.h., was rolled over and over rapidly, after which he rose and walked away still smoking.
Statistics have shown that some 69 per cent, of the deaths of pedestrians are caused by crushing, because, -whilst the human body can stand a great deal of knocking about, this is one thing it cannot resist. Much damage is also caused by dragging along the road sur
face. Consequently, if crushing and dragging can be obviated, many lives will certainly be saved.
It also seems that it is a vastly different thing being hit by a rotating body thanby one not revolving.
The time lag on the rollers is so brief that they are in rapid motion before the end of their travel on the spring, so that the forces appear to be resolved.
It is appropriate that the inventor of this device should be a medical man, Dr. V. J. Clifford, L.R.C.P., L.R.C.S., who has, in the past, had to deal with many road-accident cases, and has based the requirements of his invention on these.