A Clever Conversion for Cross country Work
Page 37
If you've noticed an error in this article please click here to report it so we can fix it.
A"Wdevice that • enables vehicles to negotiate difficult country was demonstrated last week at St. Albans,
Hens. Known as the Opperman four wheel-drive attachment, it consists of four driving wheels, two being floated in front and two behind the rear axle of a vehicle, each near-side and off-side pair being driven by chains running in oil. Each pair of wheels is free to pivot independently about the axle. . By this method, greater flotation and better_ ground adhesion are obtained than with the conventional back-axle arrange ment. The conversion provides an increased driving ratio of 1.44 to 1. No extra stress is placed upon the engine, it is claimed.
As can be seen from one of the accompanying illustrations, a steel rail above the chaincase acts as a buffer.
rubber stops being placed at each end of the case. Owing to the increased amount of space taken up at the side of the vehicle by the wheels, the petrol tank has been placed on the top of the cab.
Owing to the method of articulation and the design of the suspension, an extra ground clearance of 3 ins, is obtained, using standard Bedford wheels, the road-wheel shafts on the Opper man attachment being below the level of the rear axle. Alternatively, a greater advantage is derived by fitting 37-in. by 10-in, wheels, which give an increased ground clearance of 44 ins.
The attachment is a product of the engineering concern of S. E. Opperman, Ltd., Boreharn Wood, Herts, and is the invention of the managing director, Mr. S. E. Opperman. The device was deve loped during the war for the Ministry of Supply, with the object of converting Services vehicles for use on soft, rough, or marshy land, and the attachment, which weighs approximately 11 cwt., can, it is claimed, be fitted to a lorry in an hour.
Results derived through the use of the device are promising. The Bedford short-wheelbase tipper used at the demonstration had been subjected to exhaustive tests with the equipment, and had covered some 3,000 miles over difficult terrain where orthodox vehicles would be unable to go. On one occasion it extricated, an ordinary vehicle that had become hogged. During the demonstration the vehicle, fully loaded, was driven over steep
ridges, through ditches, and across a field of soft mud. The use of the attachment enabled the vehicle to overcome obstacles that an orthodox fourwheel-drivetruck could not tackle. Jacking and removal of the rear wheels are simple. The radius of the smallest turning circle of the Bedford fitted with the device is 15 ft. 9 ins.
The attachment is likely to appeal to operators such as farmers and building contractors whose vehicles have to negotiate difficult country. Its potentialities in the Colonial market are obvious. Preparations have been made for pro duction and delivery of this patented equipment to commence in March this year, with models suitable for The standard Fordson and Bedford 5-ton tipping lorries. Models are, we understand, also being developed for other types.
The sole coneessionnaire for the device is E. R. Tompson and Co., Ltd., 69, Victoria Street, St. Albans, Herts, -transport contractor and pioneer of the well-known Anthony-Tompson bulk spreader. The price of the Opperman four-wheel-drive attachment is £275 net ex works.