Engineer's Call for Bigger Buses
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Mr. W. Gordon Young, Chief Engineer of Young's Bus Service, Ltd., Comments on Design in Relation to Maintenance AS reported in "The, Commercial Motor" last week, a provocative paper entitled, "A Maintenance View of Public Service Vehicles," was read to the Scottish Road Passenger Transport Association on October 10 by Mr. W. Gordon Young, chief engineer, Young's Rus Service, Ltd. Most noteworthy were Mr. Young's comments on design in relation to ease of maintenance, and his emphasis on the need for legislation to allow longer and wider buses.
He said that one of the maintenance engineer's major troubles to-day was the large number of points needing regular attention and adjustment, most of them being in inaccessible and usually dirty positions. He considered that most manufacturers had neglected to insist that their designers should eliminate the need for most of this maintenance.
Better Ventilation for Differentials
According to Mr. Young, differential units in many cases need more efficient ventilation. The vent pipes are located in positions where they are readily choked. In addition, the oil now should be controlled in such a way as to relieve the seals from maximum pressure. On road haulage vehicles it has been found that the maximum gross load which can be handled efficiently by means of a worm shaft and wheel is 12 tons, and this on steady work with low ratios. Even with this load the life is not often satisfactory. Double reduction, and double reduction and epicyclic units, give long life in comparison.
Gearboxes should be of the constant-mesh type, with preselective change for vehicles engaged on city work where stops are frequent, said Mr. Young. To increase gear life and reduce oil leaks, with consequent reduction of topping-up attention, a plunger-type circulating pump should be fitted in conjunction with a deeper sump.
Hydraulic clutches are, in the speaker's experience, satisfactory in use. "The provision of a more effective oil seal would reduce the topping-up attention required," he said. "Most of the other types of clutch in use to-day are fairly satisfactory, and where provision is made for automatic alignment, when adjustment is made, little further improve
merit is possible. Any oil required for clutch-operating
mechanism could be supplied by means of a pipe from the front axle reservoir.
"The CJ. engine is undoubtedly the only unit usable for heavy-duty vehicles. The only existing competitor, the petrol engine, is certainly quieter, but the difficulties experienced in maintaining maximum performance, plus its additional fuel costs, make it uneconomic."
If springs were wider and fitted with rubber-bonded shackle pins, these improvements would eliminate greasing. The extra vehicle width desired would be most helpful in obtaining such improvements, continued Mr. Young.
"On double-deck vehicles the axle loads are most unsatisfactory, and two sizes of tyre are necessary. Increased vehicle width and length would allow modification and the fitting of 9.75-in. by 20-in. tyres all round. This I consider is a most important point, as it would enable operators to fit new tyres always on the front, and run out the latter part of their life on the rear, with consequent greater safety," the speaker declared.
Easier Brake Adjustment Needed
" The life and efficiency of brakes on modern vehicles are mainly good, but the facilities provided for their adjustment are often not as satisfactory as they should be. The use of automatic adjusters is a decided advantage. Generally, however, brakes are most inaccessible when periodic examinations have to be made or if they give trouble. An increase in vehicle width would allow wider brake drums to be fitted, and if their diameter were slightly reduced, this would assist wheel ventilation.
"The body, as far as the majority of passengers are concerned, is the bus, and the passenger's interest .. is mainly centred in a comfortable seat in a clean vehicle, having adequate ventilation, lighting and heating. The granting of extra width and length, in addition to increasing the passengers' comfort, would enable the conductor to collect his fares more quickly and comfortably, and speed up the entry and egress of passengers. The work of the cleaning staff would also be made easier," said Mr. Young.