GB2344801A - A single-deck bus with small front and large rear wheels, and corresponding seating arrangement. - Google Patents

Abstract

A low-floor, full-length, single-deck bus or coach is provided with small front wheels (2) and large rear wheels (4). The engine and transmission of the bus are placed sufficiently far to the rear of the rear axle for their weight to act as a counter balance, so that the load on the front wheels (2) remains within their rated limits. This preserves the seating capacity of the bus, in that one or more seats (16) may be positioned on top of one or both of the front wheel arch boxes (8, 10). When the seats (16) are positioned on only one box (8, 10), the access of wheelchairs to the bus interior is permitted through the space between the front wheel arch boxes (8, 10). When both boxes (8, 10) carry seats (16), the bus would usually have a second doorway between the front and rear wheel axles to permit access by wheelchairs to the bus interior.

Description

BUSES This invention relates to buses, and particularly to low-floor, single-deck, full-length buses.

Short (or mini-) buses are known having a'low floor', by which term is meant that there is a step-free layout at the entrance and exit doorways (ahead of the rear axle), and the floor between these doorway positions is flat and level. In addition, on such buses, the height of the floor between the two doors lies in the range of 320-370 mm, with entrance/exit step heights of 315-340 mm, reduced with kneeling suspension to 230-250 mm.

Such buses sometimes have small wheels at both front and rear. By'small' in this context is meant wheels of 19.5" diameter, compared with conventional large wheels, of 22.5" diameter. The quoted'size'of a bus wheel applies to the size of the metal hub on which a tyre is mounted, so that a small wheel usually carries a small tyre. Thus using small wheels at the front permits the wheel arch boxes to be significantly smaller than with large wheels. The use of such smaller arch boxes means that it is feasible to increase the seating capacity of a bus by positioning inwards-facing seats on at least one box, while leaving enough distance between the boxes for the passage of wheelchairs. Although the wheel sizes are specified in inches, it is conventional even in countries which use the metric system to refer to 19.5 or 22.5 wheels as indicating their sizes (and therefore load, etc. ratings).

The use of small wheels all round necessarily limits the carrying capacity of the bus, because of the lower loading permissible on the wheels, and because of their smaller brakes, hence the restricting of their use to buses having a maximum length of about 11 m.

GB 717 817 discloses a bus having equally-sized wheels, and with inwardly-facing seats positioned inwardly of the front wheel arch boxes.

Although US 5 813 487 discloses the use of smaller front wheels on a single-deck bus, the fact that there is no counterbalancing effect resulting from a rear-mounted power unit means that in practice the front wheels would be sized 22.5", while the rear wheels would be even larger, as they have to replace the usual twin wheels.

This invention aims at increasing the capacity of a bus, while preserving the low floor and small front wheels, by using large wheels at the rear and increasing the length and mass of the bus.

In accordance with this invention, the resultant higher mass of the bus is divided disproportionately between the front and rear wheels, so that the small front wheels operate within their rated limits. This is achieved by positioning the engine so far aft of the rear wheels that its mass counterbalances some of the increased weight that would otherwise be carried by the front wheels.

Accordingly, the present invention provides a bus that is as claimed in the appended claims.

The present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic isometric view of one form of bus of this invention; Figure 2 is a similar scrap view of the front of the bus shown in Fig. 1, with one form of modified seating; Figure 3 is similar to Fig. 2, showing a second alternative seating arrangement, and Figure 4 is a view similar to Figs. 2 and 3, showing yet a different seating arrangement.

In the drawings, the bodywork of the buses has been removed to show their internal layouts.

As shown in Figure 1, the bus chassis (not shown) carries the usual and necessary means for mounting and moving the front wheels 2 and rear wheels 4. The front wheels 2 are small, being sized 19.5", while the rear wheels are sized 22.5". Mounted on the chassis is a floor 6 which, at the front of the bus, is at a height above the ground of 320-370 mm. The front wheels 2 are separated from the bus interior by wheel arch boxes 8 and 10.

The box 10 on the near-side of the bus is only a simple box, being designed in use to carry suitcases and parcels, etc. However, box 8 is more complex, comprising a footstool 12 leading up to a platform 14 carrying two inwards-facing wheels 16. The passageway 18 between the footstool 12 and box 10 has a minimum width of 750 mm, which permits wheelchairs to pass between the boxes into a space 20 framed by three tip-up seats 22.

In the following Figures, the original references are retained. In the front seating plan of Fig. 2, the box 8 is slightly modified from that shown in Fig. 1 by replacing the spaced-apart seats 16 by a three-seater bench 24 having an elongated footstool 12.

The bus shown in Fig. 3 has a similar bench 24 positioned on the near-side wheel arch box 10, while the opposite box 8 has its top modified to act as a parcel shelf.

As shown in Figure 4, it is within the purview of this invention to have at least one seat on both boxes, in which case the provision of a footstool for the passengers may restrict the floor space between the footstools to too small a width to permit a wheelchair to pass between the boxes.

Accordingly, in such a bus, an additional doorway to the rear of the front wheels would be provided to permit access by wheelchairs to that part of the bus that lies between the sets of wheels. In this particular embodiment of the invention, both wheel arch boxes carry a three-seater bench 24, although each bench may be replaced by a pair of seats or may be big enough for only two adult passengers.

Positioned aft of the rear wheels 4 of all the illustrated embodiments of this invention is a large under-floor space in which the engine (not shown) is located, and from which a housing 24 extends upwardly, containing the usual heat-exchange and exhaust systems. The bus shown is full-size, having a length of 12 m and being designed to carry a weight of not more than 18 tonnes on two axles. In accordance with this invention, the centre of gravity of the engine and transmission system is located at such a distance from the axis of the rear wheels 4 that the engine acts as a counterpoise. This effectively reduces the load on the front wheels 2 to such a level that the small wheels are operating within their rated limits.

This invention thus provides a bus having all the advantages of small wheels at the front, while taking advantage of the longer body length and greater load-carrying capacity of large wheels.

Claims (6)

1. CLAIMS 1. A low-floor, single-deck, full-length, bus having: small wheels at the front; large wheels at the rear, and at least one seat positioned on at least one of the front wheel arch boxes, wherein the engine is located aft of the rear wheels at such a distance therefrom that the load on the front wheels is within their rated limits.
2. 2. A bus as claimed in claim 1, in which one wheel arch box carries two or three inwards-facing seats.
3. 3. A bus as claimed in claim 2, in which the said one wheel arch box includes a footstool for passengers wishing to use the respective seats.
4. 4. A bus as claimed in claim 2 or 3, in which the width of the floor space between the front wheel arch boxes, or between a box and a footstool, is equal to, or greater than, that necessary for a wheelchair to be able to pass between them.
5. 5. A bus as claimed in claim 2 or 3, in which there is at least one seat on each of the wheel arch boxes, and in which the bus has an additional doorway to the rear of the front wheels and forward of the rear wheels.
6. 6. A bus substantially as described herein with reference to, and as shown in, Figures 1 or 2 or 3 or 4 of the accompanying drawings.