AU2008101034A4 - Improved Semi-Trailer Vehicle Configuration - Google Patents

Description

P/00/009 28/5/91 Regulation 3.2

ORIGINAL

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION for INNOVATION PATENT Invention title: "IMPROVED SEMI-TRAILER VEHICLE

CONFIGURATION"

Applicant: JOHN ROBERT MITCHELL -2oo "IMPROVED SEMI-TRAILER VEHICLE CONFIGURATION" SField of the Invention o The present invention relates to an improved semi-trailer vehicle configuration and relates particularly to an improved B-Triple semi-trailer vehicle configuration.

Background to the Invention The Transport Industry in Western Australia has evolved to utilising a 27.5m Pocket Road Train configuration to transport payloads of above 36 tonnes i.e.

Sfor fuel, logging, buck and general freight. The Livestock Transport Industry has also moved to these vehicles to gain payload improvements. Mitchell's Livestock Transport were reluctant to invest in the Pocket Road Train vehicles due to a belief that there was a lowering of on-road safety compared to a conventional 27.5m B-Double semi-trailer vehicle configuration.

An innovative and far safer alternative to the 27.5 m Pocket Road Train was born through a customer focused view of operational demands and a commitment to the continuous improvement philosophy that drives the Mitchell's vision of 'Delivering Quality Paddock to Plate'. The impetus for developing a better alternative came when servicing a sector of the beef industry involved in exporting processed beef to Japan. The processor had operational requirements that necessitated a live cattle input that when processed would fill a sea container. This meant that the live cattle volume required to fill an export order was not governed by a truckload quantity, rather the supply of live cattle required had to match the target processed beef output. The resulting live cattle volume required to fill a sea container did not fit on one truck (vehicle) and necessitated a second truck (vehicle) to be utilised. The volume required for an order equated to one B-Double plus of a second single trailer truck. This outcome was not an efficient one as the second truck would be only be partly loaded and the client's transport cost increased to cover the use of both trucks (overall a 66% increase in cost per head to transport).

The present inventor considered this inefficiency as unsustainable to the customer and a waste of resources that could not be ignored. The present -3- 00oo invention was developed with a view to providing a different combination of semi-trailers that would outperform the 27.5m Pocket Road Train in on-road safety, efficiency and productivity whilst meeting the constraints in length and o weight distribution set by regulatory authorities.

References to prior art in this specification are provided for illustrative purposes only and are not to be taken as an admission that such prior art is part of the common general knowledge in Australia or elsewhere.

Summary of the Invention 0 According to the present invention there is provided an improved transport 0 10 vehicle configuration comprising: a first semi-trailer adapted to be coupled to a prime mover via a B-coupling; a second semi-trailer adapted to be coupled to the first semi-trailer via a Bcoupling; a third semi-trailer adapted to be coupled to the second semi-trailer via a Bcoupling; wherein, in use, the total length of the improved vehicle configuration is between 25m to 30m and has a payload comparable to an A-Double road train.

Preferably the total length of the improved vehicle configuration is 27.5m.

Typically each of the prime mover and semi-trailers have an axle group comprising two or three wheel axles, the axle group under the prime mover being the first axle group, the axle group under the first semi-trailer being the second axle group, the axle group under the second semi-trailer being the third axle group, and the axle group under the third semi-trailer being the fourth axle group, the spacing between axle groups being measured between the centre centres of respective axle groups, and wherein the spacing between the first and second axle groups is 6.13 0.4m; the spacing between the second and third axle groups is 6.63 0.4m, and the spacing between the third and fourth axle groups is 6.72 0.4m. More preferably the spacing between the first and second axle groups is 6.13 0.3m; the spacing -4oo between the second and third axle groups is 6.63 0.3m, and the spacing between the third and fourth axle groups is 6.72 0.3m.

Preferably each semi-trailer has a payload compartment and the length of 0 each payload compartment is not less than 5.0m and not greater than 11 metres. More preferably the length of each payload compartment is between and 10.7m. Typically the length of the first and second payload compartments is between 5.5m and 6.0m and the length of the third payload compartment is between 9.6m and 10.7m.

oO The term "B-coupling" as used throughout the specification refers to a fifth wheel coupling and turntable assembly mounted in accordance with Australian Standard AS 1771-1987 "Installation of Fifth Wheel and Turntable Assemblies." Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Likewise the word "preferably" or variations such as "preferred", will be understood to imply that a stated integer or group of integers is desirable but not essential to the working of the invention.

Brief Description of the Drawings The nature of the invention will be better understood from the following detailed description of preferred embodiments of the improved vehicle configuration, given by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates a prior art B-Double vehicle configuration; Figure 2 illustrates a prior art A-Double vehicle configuration; and, Figure 3 illustrates a preferred embodiment of the improved B-Triple vehicle configuration according to the present invention.

oO Detailed Description of Preferred Embodiments SA preferred embodiment of the improved transport vehicle configuration according to the present invention, as illustrated in Figure 3, comprises a first 0 semi-trailer 11 adapted to be coupled to a prime mover 12 via a B-coupling, a C 5 second semi-trailer 14 adapted to be coupled to the first semi-trailer 11 via a B-coupling, and a third semi-trailer 16 adapted to be coupled to the second C' semi-trailer 14 via a B-coupling. The illustrated embodiment is in the form of a _livestock transport vehicle 10; however it will be understood that other kinds of transport vehicles may also employ the improved configuration according o00 to the invention. In use, the total length of the improved vehicle configuration C is between 25m to 30m and has a payload comparable to an A-Double road train. Preferably the total length of the improved vehicle configuration is 27.5m as shown in Figure 3. Vehicles of this length and mass are permitted by Main Roads, the WA State Government Transport Authority, to travel on designated routes in the metropolitan area in WA.

The improved vehicle configuration that was developed and designed is a shortened or condensed version of a 36.5m Triple (used in Road Train Routes). However this statement belies the ingenuity and effort required to achieve its simple design and clever performance objectives. It was by no means apparent that a B-Triple vehicle configuration could be achieved within the same length constraints as a 27.5m B-Double with increased payload capacity. The challenges were to gain the absolute maximum volumetric capacity, designing the axle spacings and the layout to meet the comparable axle spacings, plus achieve optimum load distribution. In addition to this the vehicle needed to meet all the current policy constraints required by Main Roads. A prototype was designed and refined a number of times by a select group of stakeholders (including Drivers, Producers and Maintenance Staff) to meet Main Roads criteria and also ensure maximum safety from an operator's point of view.

An initial prototype was built on site and put through its paces operationally to test both on-road handling and ease of use (load/unload cattle) under a variety of conditions. The volume of cattle that were able to be loaded comfortably was in line with capacity expectation. Testing was also done on -6oO weight distribution which led to further improvements with additional 0development.

A key objective was to achieve a vehicle configuration with a total length and 0 payload comparable to an A-Double road train, but with the improved C 5 performance and safety of a B-Double. Figure 2 illustrates an example of a typical prior art A-Double road train vehicle configuration with a comparable payload of up to 83 tonne and a total length (including the prime mover) of 27.5m. This type of prior art vehicle configuration is also known as a "Pocket Road Train" as it is a condensed version of a standard road train. It comprises 00 a prime mover 20 coupled to a first semi-trailer 22 via a B-coupling. The first Ssemi-trailer 22 is in turn coupled to a second semi-trailer 24 via a dolly 26.

The first and second semi-trailers are substantially identical, each having a length of 11.lm. Unfortunately the A-Double road train vehicle configuration has reduced safety and performance characteristics compared to a B-Double, principally due to the reduced stability of the coupling afforded by the dolly 26.

Figure 1 illustrates an example of a typical prior art B-Double vehicle configuration with a comparable payload of up to 64.5 tonne and a total length (including the prime mover) of 24.9m. It comprises a prime mover 30 coupled to a first semi-trailer 32 via a B-coupling. The first semi-trailer 32 is in turn coupled to a second semi-trailer 34 via another B-coupling. In this example the first semi-trailer 32 is approximately half the length (6.4m) of the second semi-trailer 34 (12.4m). The improved stability of the B-couplings ensures that the B-Double vehicle configuration can achieve improved safety and performance characteristics compared to the A-Double. However the overall payload of the B-Double is less than the A-Double. Even if the total length of the B-Double is increased to 27.5m, the design constraints of axle spacings, layout and load distribution means that the total payload will still fall short of the A-Double.

The innovative achievement of the improved vehicle configuration according to the invention is the realisation of a design that provides a payload comparable to an A-Double road train within the design constraints of axle spacings, layout, total length and load distribution. In this connection, an important design constraint is the spacing between turntable above the fifth -7oO wheel and the second wheel axle (corresponding to the fifth wheel of an adjoining semi-trailer) of each semi-trailer. In the illustrated embodiment, as shown in Figure 3, this spacing does not exceed 6.6m. Preferably this o spacing increases with each semi-trailer, counted rearwards away from the prime mover. Hence the spacing between the turntable on the prime mover 12 and the second wheel on the first semi-trailer 11 is 6.128m. The spacing between the turntable on the second semi-trailer 11 and the second wheel on the second semi-trailer 14 is 6.487m, and the spacing between the turntable on the second semi-trailer 14 and the second wheel on the third semi-trailer o00 10 16 is6.578m.

N An important design consideration is the spacing between axle groups. This is generally the distance measured between the extreme outer axle in each group. Hence, for example, the spacing between the axle group (two axles) under the turntable on the prime mover 12 and the axle group (three axles) on the first semi-trailer 11 is 8.188m (0.685 6.128 1.375). For simplicity, throughout the remainder of the specification, the spacing between axle groups will be measured between the centre axle of each group. Hence, as shown in Figure 3, the preferred spacing between the axle group under the prime mover 12 (the first axle group) and the axle group under the first semitrailer 11 (the second axle group) is 6.128m; the preferred spacing between the second axle group and the axle group under the second semi-trailer 14 (the third axle group) is 6.628m (6.487 0.141); the preferred spacing between the third axle group under the second semi-trailer 14 and the axle group under the third semi-trailer 16 (the fourth axle group) is 6.719m (6.578 0.141).

The spacings between the axle groups can only be varied within a small window, typically about 300 to 400mm either side, whilst still gaining the absolute maximum volumetric capacity and achieving optimum load distribution. Preferably the spacing between the first and second axle groups is 6.13 0.4m; the spacing between the second and third axle groups is 6.63 0.4m, and the spacing between the third and fourth axle groups is 6.72 0.4m. More preferably the spacing between the first and second axle groups is 6.13 0.3m; the spacing between the second and third axle groups is 6.63 -8oO 0.3m, and the spacing between the third and fourth axle groups is 6.72 0.3m.

Another important design constraint is the load distribution which preferably 0 needs to be as uniform as possible throughout the length of the vehicle.

Hence to achieve uniform load distribution as well as the required payload the load on the fifth wheel axle (the centre axle of each group) in each case does Snot exceed 23 tonne. The load on the prime mover turntable assembly does not exceed 18.5 tonne.

oo In the illustrated embodiment the total height of the semi-trailers in each case does not exceed 4.6m, and is designed to accommodate two decks of livestock compartments. The length of each payload compartment may vary from semi-trailer to semi-trailer in the combination. In the illustrated embodiment the first and second semi-trailers 11 and 14 both have payload compartments 5.828m in length, whereas the third semi-trailer 16 has a livestock compartment 10.009m in length. Preferably the length of each payload compartment is not less than 5.0m and not greater than 11 metres.

More preferably the length of each payload compartment is between and 10.7m. Typically the length of the first and second payload compartments is between 5.5m and 6.0m and the length of the third payload compartment is between 9.6m and 10.7m.

Similarly, the first and second semi-trailers 11 and 14 have substantially identical axle spacings between the first, second and third wheels (1.375m), whereas the axle spacings between the first, second and third wheels of the third semi-trailer 16 is increased Extensive testing of the safety performance of the preferred embodiment of the improved vehicle configuration 10 revealed significantly improved performance compared to the A-Double vehicle configuration and comparable performance relative to the B-Double. For example, one measure of safety performance is the Tracking Ability on a Straight Path. This is a measure of the vehicle's total swept width while travelling on a straight path, including the influence of variations due to cross-fall, road surface unevenness and driver steering activity. The smaller the value of tracking ability on a straight path the lower the risk to safety associated with lane width and lateral clearance. The 00 improved vehicle configuration 10 achieved the same Tracking Ability on a

O

Straight Path as the B-Double, whereas the A-Double was 3.6% worse.

Another measure of safety performance is the Low-Speed Swept Path. This is O a measure of the maximum width of the vehicle's swept path in a prescribed 900 low-speed turn. The smaller the value of swept path width the lower the risk the vehicle will require more space than is available when turning as intersections. The improved vehicle configuration 10 achieved a 2.4% improvement in the Low-Speed Swept Path compared to the B-Double, whereas the A-Double achieved a 10.8% improvement.

00 The improved vehicle configuration 10 had the same Tail Swing and Static Rollover Threshold as the B-Double, whereas the A-Double was significantly worse in each case and -15.4% respectively). Tail Swing is a measure of the swing-out of the rear outside corner of each vehicle unit in a standard prescribed low-speed turn, whereas Static Rollover Threshold is a measure of the steady state level of lateral acceleration during a constantradius steady-speed turn that the entire vehicle can sustain without rolling over.

Even more significant was the improvement in safety performance of the improved vehicle configuration 10 relative to the B-Double in Rearward Amplification and Yaw Damping Coefficient. Rearward Amplification is a measure of the degree to which the trailers in a combination amplify the lateral acceleration of the first unit (prime mover or truck) in a prescribed lane change manoeuvre. The smaller the value of rearward amplification the lower the risk of rollover of the rearmost trailer. On the other hand, Yaw Damping Coefficient is a measure of the rate at which "sway" or yaw oscillations decay after an abrupt short duration application of steer at the prime mover. The greater the value of yaw damping the lower the risk of sway oscillations persisting following a disturbance.

The improved vehicle configuration 10 demonstrated a 5.7% improvement in Rearward Amplification relative to the B-Double, whereas the A-Double was 50.8% worse. Similarly, the improved vehicle configuration 10 demonstrated a 7.7% improvement in Yaw Damping Coefficient relative to the B-Double, whereas the A-Double was 42.3% worse.

oo Now that a preferred embodiment of the improved vehicle configuration has 0been described in detail, it will be apparent that it provides a number of c advantages over the prior art, including the following: o It achieves a comparable payload to the A-Double road train while meeting total length and other design constraints.

(ii) It enjoys the improved stability afforded by the B-couplings to achieve improved safety and performance characteristics.

(iii) It enables significantly improved livestock transport efficiencies to 00 0be achieved by reducing the cost per head to transport.

It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention. Therefore, it will be appreciated that the scope of the invention is not limited to the specific embodiments described and is to be determined from the appended claims.

Claims (6)

1. 2. An improved transport vehicle configuration as defined in claim 1, wherein the total length of the improved vehicle configuration is 27.5m.
2. 3. An improved transport vehicle configuration as defined in claim 1 or claim 2, wherein each of the prime mover and semi-trailers have an axle group comprising two or three wheel axles, the axle group under the prime mover being the first axle group, the axle group under the first semi-trailer being the second axle group, the axle group under the second semi-trailer being the third axle group, and the axle group under the third semi-trailer being the fourth axle group, the spacing between axle groups being measured between the centre centres of respective axle groups, and wherein the spacing between the first and second axle groups is 6.13 0.4m; the spacing between the second and third axle groups is 6.63 0.4m, and the spacing between the third and fourth axle groups is 6.72 0.4m.
3. 4. An improved transport vehicle configuration as defined in claim 3, wherein the spacing between the first and second axle groups is 6.13 0.3m; the spacing between the second and third axle groups is 6.63 0.3m, and the spacing between the third and fourth axle groups is 6.72 0.3m. An improved transport vehicle configuration as defined in claim 1 or claim 2, wherein each semi-trailer has a payload compartment and the length of -12- 00each payload compartment is not less than 5.0m and not greater than 11 Cmetres.
4. 6. An improved transport vehicle configuration as defined in claim 5, wherein o) the length of each payload compartment is between 5.5m and 10.7m.
5. 7. An improved transport vehicle configuration as defined in claim 6, wherein the length of the first and second payload compartments is between 5.5m and and the length of the third payload compartment is between 9.6m and
6. 10.7m. 08. An improved transport vehicle configuration substantially as herein C) 10 described with reference to and as illustrated in Figure 3 of the accompanying drawings. Dated this 2 1 st day of October 2008 John Robert Mitchell by his Patent Attorney Janet Stead Associates