Fleet Engineers Call for Progress
Page 36
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CRITICISM of the Construction and Use Regulations and of certain aspects of chassis design was made at the final lecture meeting of the Scottish Centre of the Institute of Road Transport Engineers, in Glasgow. Several short papers were read by members, including Mr. T. P. Rankin, whose subject was, "Does the Road Traffic Act Restrict Progress in Bus Design?"
He said that any designer who might have good ideas for the improvement of passenger vehicles must take into consideration many out-dated regulations, which compelled him to follow stereotyped form.
Better Suspension Needed
One might consider, for example. improvements in suspension. Independent front suspension with transverse wishbones and coil springs, he said, was a type of springing'that could do much to reduce driver fatigue and improve passenger comfort, but it was illegal. He was of opinion that the suspension regulations could all be replaced by two simple paragraphs, one of which would stiffen the present tilting test and the other would define the permissible angle between' axle and body in the tilted position. in order to control body roll.
The legally required ground clearance provided one of the greatest obstacles to progress in bus design, and he contended that there should be no difficulty in designing an artistic and efficient lifeguard.
The law should be amended so that all brakes could be arranged for servooperation, with a provision that in the event of servo failure, the band-brake lever would operate the brakes on one axle by direct mechanical action and the pedal would function similarly on the other axle.
Value of Standardization ,A paper read by Mr. H. B. Hoyland was on "Standardization of Components from a Maintenance Point of View." He said that since 1940 it had often become obvious that standardization of certain specialist components. such as ball races, cylindrical-roller and taper-roller bearings, tyres. electrical units and lamp bulbs, would not only have assisted operators during a difficult period, but would also have been a greater help to the war effort generally.
He considered that it would be an asset to the whole of the trade if the bearing manufacturers laid down the law and said: " Here is the bearing for the job: make your shaft and housing to suit." He thought members would agree that dictatorship of this nature would not interfere with the progress of design.
The next paper was read by Major W. H. Bothwell, who spoke on "Flow as an Aid to Increased Repair Output.'' 82 Flow production, in essence, he said. required a constant supply of similar articles to be similarly processed, and the times of completion of the various sta,ges must be the same or they must be multiples of the least.
Basically, flow and mass production were similar, but with the latter larger quantities and a much higher degree of reduction to stages were involved. Advantages of the flow system could be summarized as follows:—
(I) Reduction of a process to stages involves a complete and informative analysis of the process, both procedure and stage-timing being
considered. An improvement introduced at any time to reduce one
stage-time must be accompanied by a critical survey of the other stagetimings.
(2) Loss of time in movement of operatives and equipment is reduced to a minimum.
(3) Specialization of labour and equipment is necessitated. Use of Unskilled and semi-skilled labour is made economic and comparatively easy. • (4) Inspection is facilitated at all stages of processing.
(5) Introduction of financial output incentives is simplified.
(6) Unexpected difficulties, such as shortages of supplies, are at once made apparent and their full significance emphasized.
(7) Workshop layout and supervision are facilitated.
(8) Benefits of time and motion study are more easily achieved.
Money Well Spent,
It might be necessary to provide comparatively costly movement equipment,' such as conveyor belts, roller pathways, trolleys, travelling cranes, and so on and it might be found that more floor space was required, but it was confidently submitted that expenditure on such items would be found to be well justified by reduced maintenance costs.
The title of a paper read by Mr. J. More, B.Sc., was "Some Aspects of Brake Adjustment," He outlined the main methods of brake adjustment in use to-day, and asked: 'Have they yet reached the ideal of every road vehicle operator? As long as there is no change in our laws regarding brakes it can, I think, safely be said that the general form of brake gear in use to-day will continue for some considerable time. We may see the introduction of disc brakes, particularly on the lighter type of vehicle, but the heavier vehicle will undoubtedly continue to use the internal-expanding brake, with probably new forms of servo."
It would seem, he said, that the maintenance engineer would still have to cater for regular brake adjustment unless someone designed a truly automatic adjuster. He would like to say to prospective inventors that to achieve this result the adjuster must be influenced only by the wear of the brake facing; it must be capable of maintaining maximum braking effort at all times, and must be clever enough to warn the operator of the end of the brake facing life, so that the brake shoe itself did not also wear out.
"Borderline Lubrication "
The final paper was read by Mr. W. N. Henderson, chairman of the Centre, and this dealt with "Borderline Lubrication." He said that it had been written to draw attention and provoke discussion on something which, in his opinion, was due for improvement.
There was an alternative system to the primitive ones in existence for chassis lubrication, and that was the mechanical lubricator, with a mass of pipes and unions, each one to its particular point and duty. Through these pipes, at regular intervals, oil was pro jected mechanically. As components had no digestive organs, however, it was a question of speculation as to where this supply would eventually be deposited. Whether mechanical or manual methods were used to apply lubricants to chassis mountings and other components, the oil and grease were eventually deposited*on roads and garage floors, and, in the case of roads, members all knew the dangers.
Non-metallic Bushes
An interesting case came to his knowledge in connection with steel rolling mills. Between shifts of eight hours the whole plant was stopped to replace heavy bushes in the large mill-rollers. Bushes of a non-metallic material were later used, and months passed before they required renewing. Lubrication of this material was not necessary where rustless metals were used in conjunction with it. Lubrication could be by either oil or water, but dry graphite was, perhaps, the best. Something of this nature would prove invaluable to the operator, especially if fitted to shackles hardened and coated or manufactured to resist rust. Whether this form of bearing could be used for steering swivel pins was problematical, but there was no reason why experiments should not be made, although this was a matter for the manufacturers to decide rather than the operator.
Another member, in the discussion, asked: "What does the average operator do now?" Mr. Henderson -replied that they must continue as at present, although the position was ridiculous. Referring to high-pressure greasing, he pointed out that the high-pressure lubrication was speedy, but for economical reasons the hand gun was more efficient.