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Wheels on One Side Only Might be Braked!

16th January 1959
Page 60
Page 60, 16th January 1959 — Wheels on One Side Only Might be Braked!
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Which of the following most accurately describes the problem?

AN anomaly in the Construction and Use Regulations was exposed on Tuesday by Mr. E. Woodbridge, standards and technical manager of the Society of Motor Manufacturers and Traders, in a paper delivered to the automobile division of the Institution of Mechanical Engineers in London.

Some of the regulations, he said, erred by including technical requirements instead of merely laying down performance requirements. He referred particularly to the British regulations on braking systems, which required "that failure of any part of the brake mechanism must still leave available for use, on not less than half the total number of wheels, brakes sufficient under the most adverse conditions to bring the vehicle to rest within a reasonable distance, but not more than one front wheel must be included in half the number of wheels."

Change in Regulations

There was, he thought, some reason for this technical requirement when the regulation was made, but it excluded the use of both front wheels for " emergency " braking and would apparently admit braking of either the two near-side wheels or the two off-side wheels of fourwheeled vehicles, which would be highly undesirable? It was understood that this particular regulation was to be amended and that similar instances could be found in the regulations of other countries.

In the U.S.A., although each State made its own laws concerning the construction and use of vehicles, there was a National Committee on Uniform Traffic. Laws and Ordinances, which published a code as a guide to the State legislators.

c24 This code did not include technical specifications, but was clear and understandable. It laid down the legal requirements to secure safety, but was free of technical formula or specifications which might hamper design development or free competition.

Mr. Woodbridge was speaking on

standardization. "Standards and standardization. .. should," he said, "always be drawn up in such a way that they serve the industry and never attempt to master it, They should, as far as possible, be prepared and used on a voluntary basis."

Impressive results were achieved by the kind of standardization formulated by the S.M.M. and T. For instance, a range of 186 items of electrical equipment was reduced to 26. Mounting dimensions for shock absorbers were also standardized to permit interchangeability, and the types were reduced from 222 to 56.

Although British Standards Institution standards were employed by the motor industry wherever available and suitable, it was not always possible to prepare a standard which would be acceptable to several industries. It was then that an industry prepared its own standards. This was the motor industry's policy and the S.M.M. and T. had prepared standards for rubbers, leathercloths, gasket materials and so forth.

One of the most important factors in the process of development had been the progress in the science of metrology, as developed by such organizations as the National Physical Laboratory. Not long ago, the micrometer was considered a fine instrument, but now measuring instruments which automatically checked 12 or more dimensions at the same time and indicated the measurements by columns of liquid and signal lights were available.

Similarly, standard specifications for materials, methods of test, dimensions, nomenclature and processing. had made possible the adoption of flow-line assembly methods and transfer machines.

Mr. Woodbridge pointed out that some people had the idea that if an industry or group prepared a standard it might constitute a restrictive trade practice, whereas if a body such as the B.S.I. did so, it was in the public interest. Standards in the motor industry certainly did not constitute restrictive practices.

In the handbook, "Standards for the British Automobile Industry," it was clearly stated that all standards and so forth in that book were entirely advisory. A similar notice appeared in the handbook of the American Society of Automotive Engineers.

I.S.O. Recommendations

Referring to the International Organization for Standardization, Mr. Woodbridge said that this body had no legislative power and was not likely to publish many, if any, international standards, because to do so required unanimous agreement. The organization was important, however, because it made recommendations that were frequently adopted by national standards organizations when drawing up their own standards, by the Economic Commission for Europe's working party on the construction of vehicles, and by governments when drawing up regulations.

He quoted the example of coupling gears for articulated vehicles, citing the S.A.E. standard which had also been adopted by the S.M.M. and T. organizations in. other countries, and had now been accepted by the I.S.O. for international recommendation.

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