BUS DOORS: THEIR TYPES AND BEST USES.
Page 12
Page 13
Page 14
If you've noticed an error in this article please click here to report it so we can fix it.
A Review of the Different Patterns Employed, in which the Advantages of
Each are Clearly Outlined.
A S a door is not always provided to the passenger entrance of a motorbus it may be necessary to explain why the majority of doubledeckers have no passenger door, whilst it will be omitted sometimes in a single-decker, whether it has a front or rear entrance. With a
double-decker the staircase, with its stringers and panelling, forms with the hind-roof canopy some measure of protection from the weather. Also the hind platform has to accommodate two streams of passengers to the lower and upper deck respectively ; consequently, if a door is to be continually opened and closed during the busy hours it is likely to be the cause of delay. If tbe bus be a single-decker, the vestibules at the front or rear again afford good weather protection, and if no door be fitted then entry and exit are facilitated.
Whatever the design of body, the open doorway is a simple if primitive means of ensuring, under normal conditions, a good Supply of fresh air, although on a hot day an open hind entrance is not always an effective ventilator, if no windows are open in front.
A doorless bus may be satisfactory for use in the streets of some large towns, but if open country has
c28 to be traversed it will often prove very draughty and, if the journey be a long one, the discomfort of the passengers may be acute before the end of the journey is reached. If the bus has a door, then it can be used when the occasion demands and looked upon, if necessary, as an
emergency protection from the weather. It is not always possible to regard a door in this war, but if the door. be flat and takes up but an inch or two when open against a bulkhead it is not seriously in the way, even if it be mounted on the rear platform of a double-decker
operating on a busy town service.
The door is used to the utmost advantage when it protects a front entrance. If it be mechanically operated and under the control of the driver it not only affords a protection from the weather, but, with the door shutting on the front edge Of the lower step, it is a means of ensuring that the passenger suffers no • injury through attempting to board the vehicle while it is in motion. Another type of door shuts on the front edge of the landing—that is at the top of the steps, or floor level. This kind of door does not prevent the passenger attempting to get on the moving vehicle, but when shut the step-well is closed from the inside.
A door which has to swing across the floor of the platform is apt to be an inconvenience. A single or folding front door of this• pattern opening inwards must open towards the dash; consequently it forms an obstruction to the driver's outlook. If the door opens outwards above the steps there will not be room for it to open in one piece.
A normal width of doorway is about 2 ft. 4 ins., and this measurement is not available from the side of the body to the pillar at the side of the opening in the front bulkhead. This is owing to the fact that the .ciciorway in the front bulkhead is off-set, as the result of the steering being designed as for a driving seat the full width of the body. The bulkhead entrance can be placed in the centre if the steering column be mounted, say, 1 ft. 8 ins, from the longitudinal axis of the chassis.
At the back of the body almost any type of door may be used and the opening in the bulkhead may be made centrally, as the design of the chassis does not impose any limitations here.
Doors reaching to the floor and opening outwards are also used as pair opening to the right and left, or hinged vertically in the middle, so as to fold in halves as well as to hinge. There is not much to choose between , the two types, but two separate doors lie a little more compactly against their respective panels than a folding door ; the_ latter, however, leaves one side free for the attachment of a commode handle directly to the body at the entrance.
For the one-man-operated singledecker, a door hinged on the offside pillar of the front bulkhead entrance is a help to the driver, as It can be fitted with a shelf and sliding window so as to form a convenient method of receiving fares. Some proprietors will prefer the door to be used when the bus is in service as a partition rather than as a door, and arrangements can easily be made to hold it in position with a top and bottom bolt. In this case there should be another door fitted to the step entrance.
Hinged doors are sometimes used for partitions which divide the maip portion of the bus into two saloons, but this kind of door is suitable only when the door can open in front of a longitudinal seat, where the gangway is wider than it is between the crosswise seats. If the top saloon of a double-decker is to be fitted with a door, it should open inwards against the off side, where, in fine weather, it can be fastened without cans:. lug an obstruction.
The private-body style of door—that is, one having a turnuncler and sidesweep and usually an adjustable window —is not suitable for the main entrance of a service bus, because it opens beyond the width of the body and forms an obstruction when the vehicle is drawn up against the kerb. It is used for the allweather coach and long-distance bus, because it improves the general appearance and is in keeping with the luxury of the interior appointments.
TM overhanging door is of less moment when the stages are comparatively long, but it is not the ideal door from the . operating point of view. This style of door has its uses for the service bus as an emergency exit.
With the low-loading chassis de signs of emergency exit are now greatly improved, because even if no step be provided the descent to the road is comparatively easy. At the same time, it is not a difficult matter to make the descent as safe and as easy as the main entrance, by recessing the floor and adding a step with a flap or shelf attached to the back of the door to fill the gap, or a step can be placed beyond the end of the body. The recessed step is the better arrangement, because it does not tempt anyone so inclined to " hang on" at the back.
The sliding door is a useful pat tern for attaching to a bulkhead. Formerly, many frobt-entrance buses had sliding doors opening towards the off side, but the practice has been discontinued owing to the introduction of the mechanically operated door at the steps. A: sliding door should be hung on a well-designed mounting offering as little friction as possible, with no loose parts to set up rattle. At the bottom it should be fitted with a T-iron, which engages with a floor • channel.
The sliding door is also employed for closing the bulkhead of a rear-entrance bus. Here, again, it opens to the off side, but if used fOr the lower saloon of a double-decker it must open towards the near side.
The sliding door, owing to its compactness, is also adopted as an emergency exit for the rear-entrance bus. It is usually fitted in conjunction with a forward-driven chassis and Is
mounted on the front bulkhead, immediately behind the driver's cabin. • The same kind of door could be used for a. bus having ordinary steering, with. an opening in the centre or towards the near side of the front bulkhead. • The mechanically operated door is
framed in hard wood, about in. thick. As a door reaching to the step is often .6 ft. high and the bottom line of the glazed panel is usually, on a level with that of the main windows, the door measures about 4 ft. below the window, so that there is room for dividing this Bpace into two panels, if required.
If the door be. flush with the body at the waist-line it will project At the bottom, because the door is flat and the body panels have a • turnunder. A board is screwed to the face of the bulkhead so as to form a shutting edge, and a length of rubber hose is attached to the edge of the door to form a weatherproof joint. Instead of grooving the panels into the door framework they
may he fastened on top of it, so that the door has the same kind of finish as the iest of the body.
Although the door should be flat and as thin as Possible, so that it may fold compactly, it need not be devoid of any ventilating device: It may have sliding glass panels in the upper part, or fixed glass louvres, so long as they do not project beyond the thickness of the door, or the top-rail may be slotted to form a ventilator.