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Spending to Save

23rd September 1938
Page 71
Page 71, 23rd September 1938 — Spending to Save
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Which of the following most accurately describes the problem?

on Brake-testing Apparatus

The Economic Aspect of the Use of Elaborate Brake-testing Equipment

By

H. SCOTT HALL, m.I.A.E., M. I .T.A. THE aggregate expense of equippiug a garage for the maintenance of commercial vehicles may assume formidable proportions but, if each item be considered separately in relation to the work which it has to do, and the economy and saving of time which will result be considered in comparison with the capital outlay on each, the decision—to buy or not to buy—is not usually difficult to make.

There is one piece of equipment, however, which so far as initial expenditure is concerned, falls into a class by itself. I refer to brake-testing equipment of the kind made by the following concernsl—Bendix, Ltd., King's Road, Tyseley, Birmingham ; Tecalemit, Ltd., Great West Road, Brentford ; Joseph Bradbury and Sons, Ltd., Braintree; the British Weaver Manufacturing Co., Ltd., 10, Paul Street, E.C.2; and Mann Egerton and Co., Ltd., 5. Prince of Wales Road, Norwich.

Justifying the Outlay.

The all-in cost is in the neighbourhood of £300, more rather than less. and that is a sum which gives pause to even the most progressive transport manager. haulier or passenger-vehicle operator. It represents, in interest, depreciation and maintenance, round about £75 per annum, and the question is. how is such an outlay to be justified?

The problem of deciding is complicated by the fact that there is, on the market, a much less costly type of apparatus designed to facilitate the testing of brakes. This is satisfactory if the be-all and end-all of the operator's desire is to check the efficiency of his brakes, and the owner of one, two or even three vehicles will probably decide that the expensive equipment I have in mind is entirely outside his scope. The fleet owner is, however, in a different category and can probably make economic use of the more comprehensive apparatus.

The real brake-testing machine, besides registering the efficiency of the brakes, which it does dynamically, also affords information on the following important subjects. It enables the operator to detect the presence of uneven or distorted brake drums, which cause locking of wheels, with consequent skidding and rapid tyre wear. It indicates the presence of greasy and glazed facings, which cause inefficiency at low speeds and possibly "grabbing " on heavy application. It shows if there be any lack of equalization or balance in the brakes, either front to rear, or near side .to off aide, or a combination of these. Unbalanced brakes are dangerous and cause swerving and skidding. In enables the opesator to detect a broken spring or loose spring U-bolts, defects which, otherwise, would certainly not be discovered in the course of an ordinary mad test of the brakes.

It should further be appreciated that the elaborate machine does all this in less time than it takes to check and adjust the brakes by other means. First, and probably foremost, because it eliminates the need for taking the vehicle on to the road ; secondly, because the complete job of testing and adjusting is done much more quickly.

The foregoing are factors which directly affect the cost of maintenance. Other savings, less obvious and certainly less direct, can be credited to this more expensive equipment, as will be shown.

The direct economy—the time saved in testing and correcting the brakes— is indicated by the following figures relating to four-wheel brakes on a 6-ton lorry.

It is assumed that two mechanics be employed. With ordinary equipment the time needed to jack-up the vehicle, affect minor adjustments and remove the jacks, can be taken as 25 minutes; /5 minutes is necessary to take the vehicle on the road, test the brakes and return. A further allowance is necessary for subsequent road tests, assuming that the brakes are found not to be satisfactory on the first test. A reasonable allowance is 20 per cent, of the above, a further eight minutes, so

that the average is 48 minutes, a total of 96 man-minutes.

Using the more elaborate equipment and thus eliminating the need for a road test, for jacking-up, or for removing the jacks, the whole job can be completed in an average of 10 minutes, and if two men be employed that is 20 man-minutes. The saving, as between the old method and the new, is thus shown to be 76 man-minutes. This is equivalent to approximately 5s., if proper allowance be made for overheads, management expenses and the like. Assuming that the work be done every 2,500 miles the economy per vehicle is equivalent to 0.025d. per mile.

The indirect economies, to which I have referred, arise from the fact that the vehicle with efficiently maintained brakes is cheaper to run. There is a saving in tyre wear, for reasons already stated, and if this he taken as 121 per cent., the total is 0.075d. per mile. There is a saving in brake facings, due to the fact that the braking effort is evenly spread between the four wheels, and this saving might easily be equivalent to 0.01d. per mile.

Indirect Economies.

There is also considerable economy in maintenance of bodywork, because unbalanced brakes cause chassisstresses which are inevitably transmitted to thc body, and cause defects to arise. A reasonable estimate of the saving, here, is 0.040. The total economy from all these_ sources is 0.15d. per mile and that, on a vehicle covering 48,000 miles per annum, is equivalent to £15 in a year.

It would thus appear that installation of this expensive class of equipment would be justified in a fleet of five 6-tonners covering yearly 48,000 miles each.

Possibly, a more direct basis, for measurement, is fleet mileage, and it would appear that if that mileage reaches 240,000 per annum it would probably pay to install high-class brake-tesine equipment of the type named.

Tags

Organisations: M. I .T
People: Prince, M.I.A.
Locations: Birmingham, Norwich

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