A Technical
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Review of
REAR-ENTRANCE CONSTRUCTION
Our Bodybuilding Expert Deals with Methods of Operating Rear Doors for Coaches and Buses, and Outlines a Number of Systems of Building
THOSE who favour the rear entrance for passenger vehicles, in preference to the front one, point out that it is safer because it is beyond the wheels, also it may be designed for approach either from the side or back.
A. large bus or coach has an overhang beyond the rear axle sufficient for the mounting of a sliding door operating at the step level. As the door slides to the rear, the length of the body beyond the entrance must be at least equal to the width of the entrance, without taking into account any rounded back corner.
To the inside of the ton of the sliding door are attached two hangers, which are connected to a roller running on a bar or tube. If a ball race be used, the bangers are
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Screwed to a runner bar which operates between an upper and lower ball race.
At the bottom, the door is hung in a similar manner. Again, the fitting is on the inside, but a special rail is required, mounted under the step, for fixing the bottom channel.
• Another type of bottom fixing consists of a spring-mounted roller. This is attached to the back of the door. and the roller works on a guide rail screwed to the step. Sometimes this is let flash into the step, but this is not essential, because a tread plate fastened in front protects the rail and has the effect of reducing its amount of projection.
The top fitting of the sliding door is wholly or partially concealed by a wood finisher, and the bottom one, except any guide rail attached to the step, is hidden by the construction of the step well.
Many rear-entrance coaches have a pair of doors opening outwards at the floor level. When open they are held by a catch against the partitions of the step well and usually they are hand-operated separately.
In fine weather, the doors are often left open, but if the conductor wishes to open and close them frequently, it is an advantage if they be interconnected, so that the move
raent of one transmits the appropriate movement to the other. This may be effected by means of a set of levers mounted on top of the doors, with the fulcrum bracket attached to the inside of the cant-rail.
A. similar type of operating mechanism may be employed for a pair of doors which open inwards at the step level. In this instance, the levers are mounted under the step.
When the door is of the folding pattern and is hinged vertically in the middle, the operating lever is fixed conveniently on the back of the rear partition of the entrance. The rear half of the door is hinged to the body and the free edge of the trailing half runs in upper and lower guides, which may be straight or curved. In either case, the angle of the moving door is continually altering, consequently some form of swivel mounting is necessary.
With the normal height of chassis, only one step is required between the ground and floor. When this step is accessible from the rear, it extends to the back of the body, which is recessed for the width of the step, although the full width of the roof is maintained throughout.
The length of step available depends on the amount of rear overhang of the body and the space be tween the entrance and wheel-arch. A step 4 ft. 6 ins, long is not =usual.
When the side of the body is recessed in this manner, a sliding door requires a special rail for its top guide, because the cant-rail is not available. A folding door opens inwards against the bulkhead at the end of the wheel-arch seat.
A pair of hinged doors is comparatively' rare, owing to the space occupied by the rear door when it is open inwards. If the rear entrance has a single hinged door, it is set at an angle with the edge of the platform and it opens forward against the bulkhead.
This kind of door has a commode handle on the back of it. With the other type of door there is a long handle on the bulkhead and another on the rear pillar of the entrance. Instead of the second handle, a grab pole is secured to the outer edge of the step and extends to the contrail.
Rear entrances are often doorless, a style of doorway which has been found effective for use on the double-decker. The entrance of the double-decker is copiedmore closely if the single-decker incorporates a chassis with tail ends lower than the main portion, so that the rear platform is reached directly from the ground, there being a step at the rear bulkhead from the platform to the main saloon.
The body should be about 3 ft. long behind the entrance if a comfortable seat for four passengers is to be provided across the back .of the platform. This measurement allows sufficient leg-room for the passengers sitting close to the doorway.
As a rule, the back seat seldom accommodates more than three passengers. More landing space is available if this seat be an off-side longitudinal one, instead of facing forwards.
The near-side rear corner of the platform may be open or enclosed. When panelled and the back seat does not extend into it, there is a handy space for lockers, etc.
Such an arrangement is depicted in the illustration at the top righthand corner of this page, where it will be observed that a small locker has been built into the space below the roof. An additional locker can be accommodated beneath the rear seat.