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THE DESIGN OF THE ALL-WEATHER COACH.

1st January 1924, Page 19
1st January 1924
Page 19
Page 20
Page 21
Page 19, 1st January 1924 — THE DESIGN OF THE ALL-WEATHER COACH.
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Which of the following most accurately describes the problem?

A Survey of the Problems which have to be Solved by the Designer of a Coach Rapidly Convertible from Open to Closed, and of the Types in Use,

0 WING TO the vagaries of our climate, the coach body must be provided with some form of weather protection. For the. smaller type of body, the simplest Method is to fit a Cape-cart hood which can be worked from one pair of body centres. It is a real " one-man " device, it. is not of undue weight and is reasonably compact when folded down. For the longer body, a special mechanism is desirable, since, even if it is possible to design an easily controlled hood on the lines of the smaller patterns, the number of parts required entails a somewhat bulky and heavy pile of Ironwork in the folded position which rests on that part of the body already heavily loaded and usually well beyond the hind axle.

Improvements which have been made in the Capecart hood, for the coach having a comparatiVely large seating capacity, have been in the direction of making it caster to control, such as by sliding it on rails, mounting the bows so that they fold down behind each row of seats, and making the hood cover detachable, so that it can be separately rolled up. Also the side curtains are now designed to open with the doors, and, making due allowance for the difference in size, the coach body has an all-weather hood as effective as that fitted to the modern touring car. . The coach proprietor, however, although he may be the fortunate possessor of an elegantly shaped coach; fitted with an easily worked hood, is well aWare that the private motorist has the choice between an open touring car with the all-weather hood and one with the all-weather body provided with glass WindowS which drop into the body sides. The latter is a type of coachwork. giving full protection frem the elements, a clear outlook for the passengers and more suitable for winter use. Moreover, there are no curtains to dispose of separately, and the body, when open, has an appearance equal to that of the car with a hood.

During the last three years or so, the coachbuildeihas spent much time and money in order to satisfy the demand, of the coach owner for an all-the-year-round body. The problems to solve are by no means easy. The initial difficulty is the size of body required. The largest private allweather car seats seven persons and it is seldom more that 9 ft. 6 ins. long and 4 ft. 6 ins, wide, whereas if a large seating capacity is demanded, the coach body will be twice as long as the larger private car, and not less than 7 ft. wide. One can, of course, make the fittings stronger with more ample hearing surfaces, but, in addition to this there must be more anaving: parts, because the body is longer, whilst, above dii (both literally and figuratively), there -is a large expanse of. twill..or other hood cover to deal with. This is difficult to control, not merely because of its, weight, but, also owing to its width.

If an all-weather coach accommodating say 14 to 1.6 passengers (that is twice the capacity of a private car) is large enough for the purpose concerned,. then there is no difficulty in providing a simple mechanism, because a ono-man hood will extend over four, and with' suitable front-pivoted stays five, rows of seats. Ease of working is facilitated if the width of the body is reduced to sufficient for four persons abreast, including the central gangway, the passage being made, when required, by the use of hinged gangway seats. The hood, however, must be modified, because,. with the usual pattern the body centres are wider apart than the body sides, so that the hoopsticks fall outside the panels. It will be readily seen that, if the hood is not altered and is used in conjunction with drop windows, there will be two or three inches space on each side between the outer faces of the windows and the sticks. This would have to be filled in with a somewhat unsightly make-up piece. The hood fitting must, therefore, be mounted inside the body, the last upright stick pivoting much in the same fashion as in a landaulet or cabriolet.

The disposal of the side windows presents little difficulty so far as mechanism is concerned, but their presence has considerable influence on the general design of the body. The body side which accommodates a glass window must be an inch thicker than one which does not. When one is designing to a 7 ft. 2-in, or 7-ft. 6-in, limit, and there is a double row of crosswise seats and a central gangway, this extra inch entails a corresponding loss of space of twice the amount in the gangway. As the supports of the window, whether they are metal guides or wooden pillar tops, must fall flat on top of the elbow rail of the body, the glass must be entirely concealed. This means that the body sides must be deeper than those of a, body 'having aide curtains, a depth which is controlled by the height of the wheel arch. A compromise may be effected by curtailing the headroom an inch or two and bringing the bottom line of the top cover as low as possible. If the chassis with a law loading line becomes popular, this will create a fresh problem for the coachbuilder, because, if the frame is lower, and 'the hind wheels remain the same size, the wheel arch must necessarily be relatively higher. Owing to the use of twin hind wheels, the wheel arch is usually wide from back to front, so that one cannot use a specially shaped glass rim, to shoot the glass behind the arch, but it would be possible to fold the window in half horizontally before dropping it, the disadvantage being a slightly thicker side casing and again less gangway. As the designer prefers to have all the windows the same size, it is seldom that the wheel arch only influences one window ; consequently, if special devices have to be made here; it will, as a general rule, have to be repeated four times.

Many Varieties of the Ail-weather Coach.

The definition of an all-weather body, so far as private-car construction is concerned, is :—a body which has no internal cross partition, that can be either entirely open or defied and is fitted with glass windows. The term " all-weather " as applied to the public service vehicle, has a wider application. It may he described as a multi-seated body which can be wholly or partly converted from, a closed body to an open one. It has drop or hinged glass windows' and usually a seating arrangement with a central gangway. In all types the windscreen and its supports are fixed. The all-weather coach having the 'above characteristics may be conveniently divided into five classes, as follow

(1) A body with a hinged side framework above the waist. The Ride framework provides the runs for the drop windows and, at the top, a bearing for the sliding bows.

(2) A body which has•a hinged, fixed, or partly fixed side framework, with a roof cover which opens from the sides to the centre.

(3) A body which has a roof cover which opens lengthwise to one or both ends.

(4) A body which has a fixed roof, the body opening at the sides only. (5) A composite body having a forward coach portion and a rear saloon or bus portion.

The "Quadruple Purpose" coach body built by London Lorries, Ltd., has an all-metal Beatoeson headwork, the side framework being made up with the lower parts of the pillars as one unit. The pillars are -hinged just below the waist-line, and again to

B36 the cant rail, so that the whole of this superstructure may fold down, or "lozenge " as one unit, at the rear, and lie on the top of the waist rail, the Pillar tops being concealed. Each pillar is grooved for the reception of a sliding frameless mechanically operated window. The side entrance is in front immediately behind a Vee-shaped screen. The cant rail is extended over the door, and has a double hinge at the rear pillar. To open the head the front rail of the hood over the screen is unlocked, the cant rail is detached from the screen, and that part over the door, by reason of the double hinge provided, swings right over and lies on top of the main portion. The pillar top, to which the front part of the cant rail is hinged, is only grooved for the first side light, the door window being held by a separate hinged glass frame guide on each side. The front rail over the screen locks against another one of similar substance,, and a water plate is provided on the top of this joint, as in ordinary Ian daulet construction. .

The Hinged Side Hood Framework.

The-end pillar top is set forward, so that there is room for it to hinge down by the side of the back seat. The side framework is held rigidly here by a separate knuckle joint, so that, in conjunction with its front fixing, the whole may be erected independently of the hood and the windows individually adjusted as desired. The door window may be raised or lowered, whether the side framework is up or not.

The cover of the head is supported on a rear stick or hoop, with a built-up earner to give the fashionable rounded hind top -corner, and an upright ona abutting on to end pillar top, together with a series of bows which slide on top of the cant rail. This upright stick has, made up with it, a pair of forwardly projecting arms, which constitute the top part of the cant rail at the rear and is long enough to accommodate all the sliding bows when assembled. This upright &tick has its own pair ,of outside joints, so that the head is strained into position independently of the window framework. The top rear portion of the cant rail which carries the assembled bows can then hinge down with the upright stick, the right angle being rigidly maintained by the use of a strut. The head cover by the back seat folds down as in a landaulet, but the main roof portion is attached only to the rail above the screen and to the sloping stick at the rear. The cover can then be rolled up with the front rail and strapped to the stick at the rear. The windows are dropped, the hood unlocked, the bows slid to the rear, the cover rolled, the side frames are collapsed, and the hood folded down at the rear.

The sliding bows are swivel-mounted, so that they would not bind should they, whilst being moved, not be at right angles to the cant rails. The mechanism is also varied so that a second side door is provided at the rear, in order to conform to Scotland Yard requirements. This door, then, has a pair of hinged glass frame carriers, as with the front one, enabling the door to be opened when the window is up. The windows are raised by means of a bevel gear actuating a vertical screw, threaded through a nut fastened to the bottom window channel. This mechanism is all in front of the glass, so that no space has to be left under the window. The connection between the nut and bottom window channel. is by means of a slotted plate, allowing sufficient universal movement to prevent any fracture of the glass.

The general appearance of the "Quadruple Purpose" body is elegant, owing to the use of a metal side framework and frameless glasses. The general design is the result of successful. collaboration between the coachbuilder and manufacturer of the fittings, the former being concerned with easy

manipulation and such practical considerations as affect the body generally, whilst the engineer has utilized his experience to ensure a sound mechanical job without undue weight. The body can be used in the following positions:— (1) Entirely enclosed, hoed and windows up. (2) Hood up and windows down.

(3) Hood down and any or all of the windows adjusted at any height.

(4) Entirely open, windows and hood down. Roof Cover, Opening Transversely.

Another method of attacking the all-weather coach problem is to work on the foundation of a bus or saloon and design the superstructure so that it may be converted to give the maximum of ventilation and open roof work. There are two important examples of this class where the roof opens towards the centre, namely, the " Charabus," as built by Christopher Dodson Ltd., and the all-weather coach as made by Messrs. Strachan and Brown.

The Charabus has an enclosed driving seat and a similarly roofed-in portion at the rear, both having side doors. The two fixed roof sections are connected by a central beam, and the body is so arranged that the remaining portion on each side of the roof and the sides of the body above the waist may be entirely open. The cant rails are connected to the middle beam by,means of hinged struts al:owing them to be held in their normal position at the top of the side pillars, or to lie against the middle beam. The intervening space is filled with waterproof fabric. The side pillars are hinged at the waist-line, so that, after the windows have been dropped into the sides of the body, they may be folded down horizontally on the elbow rail.

The struts which hold the cant rails away from the central beam have hooked ends, which enter slots made in the inside face of the cant rails. The end of a slot is closed and the strut hold tightly by means of a plate spring. The cant rails run in a guide at each end formed in the roof bars, and the roof cover is bolted on at intervals, so that the material folds in a series of neat upward puckers. To draw the ends of the cant rails into place when the roof is closed, a screw bolt is provided which draws it outwards and downwards.

The striking feature of this body is the use of a cant rail which can be moved transversely, the absence of intermediate hookstieks. being compensated by the use of hinged struts. Having front and back entrances, and a seating plan like that of a single-deck bus, the Charabus is highly suitable for use with a conductor, plying for hire as a stage carriage, in addition to its value as a. pleasure coach.

The success of the Strachan and Brown all-weather coach is due to the fact that the conversion of the body to an open one is accomplished without having to fold any portion of the side or roof fram ing. In general appearance it is a well-propor tioned saloon body. The windows are made to drop and the roof to open on each side towards the centre.

These movable roof 'sections each consist of a rolling shutter made up in a similar manner to that of a roll-top desk, the slats being on the underside. The shutter is guided in grooves forined in the hoopsticks on each side, and it is wound . on a apring roller protected by a housing running the hill length ' of the roof opening.

A hoopstick is framed in at the top of each -side pillar, so that there is a separate shutter to each side light, with a fixed roof portion at each end of the body, connected by a central beam, which supports the housing of the roller for the shutters on

each. The amount of roof opening can be

varie as required, likewise the side ventilation, whilst it can be adapted to any seating or entrancearrangement, and is suitable for either public or private hire.

Hinged -Roof Lids.

Instead of rolling up sections of the roof to the centre, the middle portion of the roof has been made up as lids, which, by means of a link motion, can be lifted on to a fixed roof portion at the sides. This idea has been adopted by Palladium Autocars, Ltd.

The all-weather coach is also designed with a fixed side framework, and the roof portion to open lengthwise. A body of this description is made by the Northern Counties Motor Engineering Co, Ltd. The front and rear portions of the roof are fixed, as in the Dodson, and the Strachan and Brown bodies, with the middle part constructed on the lines of a Capt-cart hood. The hood is mounted on bows, sliding, not on the top of the side framing, but on an inner cant rail. This not only allows the hood to be made narrower, and therefore easier to slide, but a sharply rounded corner at the cant rail can be adopted, enhancing the general appearance. The number of hoopsticks is sufficient to give a good support to the twill, and to ensure the neat disposal of the waterproof cover when the flexible roof is in its open position. When closed, the roof is drawn forward tightly by means of a special device fitted above the driver's seat.

, Another method of opening the central portion of the roof is to construct it as two sliding lids the full width of the body, one sliding to the front and the other to the rear. This style of body has been adopted by Mr. T. Anderton, of Bradford.

[In our next issue the conclusion of this article will deal with quick-operating roof covers and a suggestion for a double-folding head.—ED., C.M.]

Tags

Organisations: Scotland Yard
Locations: Bradford

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