GB2513146A

GB2513146A - Trailer

Info

Publication number: GB2513146A
Application number: GB201306949A
Authority: GB
Inventors: Dr Matthew Turner
Original assignee: EPL Composite Solutions Ltd
Current assignee: EPL Composite Solutions Ltd
Priority date: 2013-04-17
Filing date: 2013-04-17
Publication date: 2014-10-22
Also published as: GB201306949D0

Abstract

There is described a trailer 102 having a semi-monocoque structure or a trailer having a shell 106 which forms a primary structural element of the trailer. The structure may be formed from a material such as glass reinforced plastic (GRP). There may be spars 122 and stringers 132 to add strength to the structure. Bulkheads 126 may be included along the length of the trailer. The invention is particularly suitable for the construction of semi-trailers for lorries or trucks. Also claimed is a method of manufacture of such a trailer.

Description

TRAILER

This invention relates to a support structure, and particularly, but not exclusively to a trailer chassis.

The invention relates to all types of trailers, but particularly to semi-trailers which are adapted to be pulled by a tractor/tow vehicle.

The use of trailers goes back thousands of years, since a trailer provides a convenient means for transporting goods and materials.

In more recent times, trailers have typically been made using metal such as steel or aluminium.

is A semi-trailer is a very convenient means for transporting goods over long distances and typically will be pulled by a tractor or tow vehicle such as a lorry or truck.

Known semi-trailers tend to comprise a structural element onto which at least one axle or wheelset is attached. Semi-trailers can include bodywork comprising fully or partially enclosed structures comprising one or more of a base, or floor, a roof, sidewalls and front and back walls.

A trailer typically comprises at least one axle which extends transversely across the trailer and is connected to the trailerbed for suspending wheels.

A trailer is typically rectangular in shape and is longer in length than it is widthwise. Such a trailer typically comprises a king pin and fifth wheel system for connecting the semi-trailer to a towing vehicle.

Known semi-trailers are typically made from metallic materials. The main bearing members are a pair of main runners extending longitudinally along the length of the trailer and typically formed from steel. Further support for a load carried on the trailer is provided by cross members which extend at substantially right angles to the main runners and are attached to the main runners by bolting or welding. The main runners and the cross members are typically attached to a floor of the trailer. A floor, or deck is supported by the main runners and cross members. The deck may comprise a plurality of deck sections which are held in position by any convenient means such as by screws or mechanical location.

There is an ongoing need to reduce the weight of an empty trailer as much as possible in order to make transportation of goods more economical and more energy efficient.

Road haulage is by far the most important form of transport for goods in Europe, and is expected to grow significantly over the foreseeable future. This growth has a potentially negative effect on the environment. This is particularly because most semi-trailers are pulled by a tow vehicle running on diesel, although some vehicles are able to run on both diesel and natural gas. Nevertheless, road haulage contributes to a large percentage of CO2 emissions within Europe and indeed across the world.

The weight of a heavy goods vehicle (HGV) is also significant since the weight itself may cause damage to roads and bridges.

There is therefore a need to reduce the weight of trailers and semi-trailers whilst at the same time maintaining their strength. There is also a need to create a more aerodynamic design of a trailer or semi-trailer which is multi-functional in that it is capable of being used as a boxed, flatbed or curtain sided trailer.

According to a first aspect of the invention there is provided a trailer having a semi monocoque structure.

A monocoque structure is one in which the skin, or shell of the structure absorbs, or resists most of the stresses to which the body is subjected.

A semi-monocoque structure is a similar structure in which the skin, or shell, is reinforced with an internal structure such as longitudinal spars and/or transverse bulk-heads. Thus in an embodiment of the invention in which the trailer comprises a shell, the shell may be regarded as being formed from a skin, and the skin may be reinforced with an internal structure.

According to a second aspect of the invention there is provided a trailer comprising a shell, which shell, forms a primary structural element of the trailer.

As mentioned hereinabove, trailers have traditionally been formed from runners comprising, for example, I beams extending longitudinally along the trailer, and transverse support structures attached thereto. A deck is typically positioned onto, and may be attached to such a structure.

The inventors have realised that it is not necessary to have such a structure, and the trailer according to embodiments of the invention comprises a hollow shell in which the deck forms part of the shell.

The shell may comprise a hull forming a base of the shell, with a deck forming a top portion of the shell.

A main structural element forming part of a trailer according to aspects of the invention is thus a hollow structure, the external shape of which is defined inter alia, by the shape of the shell.

The deck may form an upper portion of the shell and may be formed integrally with, or may be attached to the hull.

In some embodiments of the invention, the hull may comprise a plurality of hull portions, and in some embodiments the hull may comprise two hull portions. The hull portions may be integral parts of the hull, or may be formed separately thereto.

The hull may extend longitudinally along some or all of the length of the trailer, and in embodiments of the invention comprising two hull portions each hull portion may extend longitudinally along some or all of the length of the trailer.

The trailer may comprise a channel extending longitudinally along some or all of the length of the trailer. The channel may comprise a spar.

The channel may be positioned between the hull and the deck, in some embodiments.

The spar may comprise one or more lateral walls which lateral walls may extend vertically. However in some embodiments of the invention each lateral wall extends at an as angle to the vertical, which angle may be between 0° and 900. In some embodiments, each lateral wall forms an angle of between 15° and 75° to the vertical.

In embodiments of the invention comprising two hull portions, the spar may be defined by one or both hull portions. In such embodiments the spar may form a channel extending between the two shell portions.

The spar is not an essential feature of the trailer according to aspects of the invention. It can however be advantageous to have such a channel since it reduces the weight of the trailer, and also provides a convenient recess along which cables etc may extend.

The trailer may comprise one or more stringers which extend longitudinally along some or all of the length of the trailer. The stringers provide additional strength and stiffness to the trailer. Thus when the trailer comprises a semi-monocoque structure, the stringers may be regarded as part of the internal structure which imparts strength, stiffness, rigidity and buckling resistance to the shell and helps transfer load.

The trailer may comprise a plurality of bulk-heads spaced apart running transversely along the length of the trailer. The bulk-heads may be positioned along all, or a part of, the trailer.

The bulk-heads add further support to the trailer, and, like the spar, may be regarded as an internal structure forming part of the semi-monocoque structure.

Each bulk-head may be attached to the spar and/or stringer(s), or may be separate therefrom.

In embodiments of the invention, the trailer may comprise first and second side structures, each of which side structures extend longitudinally at least partially along the length of the trailer.

The first and second side structures add strength and or stiffness to the trailer. They also allow for easy attachment of peripheral components such as load hooks, curtain sider and box body post integration, front bulk-head support, rear bulk-head and doorframe support.

In embodiments of the invention where the structure of the trailer is a monocoque or as semi-monocoque construction, the first and second side structures form part of the internal structure forming part of the semi-monocoque structure.

The side structures may be attached to the a stringers and/or the bulkheads, or may be separate therefrom. In some embodiments one side structure may be attached to a stringer and/or the bulkheads and the other side structure may not.

In some embodiments of the invention, whether or not the side structures are attached to a stringer and/or the bulkheads, they may abut with a stringer and/or bulkhead.

In embodiments of the invention one or both of the side structures may be spaced apart laterally from the spar, and may be positioned towards edge portions of the trailer.

The trailer may be formed from any convenient material and in some embodiments of the invention the base is formed from a polymer composite material.

Any suitable composite material may be used, and in some embodiments of the is invention the composite material comprises glass reinforced plastic (GRP) or glass reinforced polymer. GRP is known to be a lightweight strong and robust material. Other suitable materials may be polymer composites reinforced with carbon fibre, carbon nanotubes, aramid fibre, among others.

According to a third aspect of the invention there is provided a method of manufacturing a trailer according to the first or second aspects of the invention including the steps of: 1. forming a hull; 2. forming a deck; 3. forming one or more further structures providing internal strength, stiffness, buckling resistance or load transfer to the shell; 4. joining together the components to form the trailer.

Each of the parts may be formed from a polymer composite material.

Each part may thus be formed by placing reinforcing fibres into a mould and then as introducing a thermoplastic or thermoset resin into the fibres.

The thermoplastic or thermoset resin may be introduced into the mould by any suitable means such as by injection, infusion, pre-impregnation or combination.

After the thermoplastic or thermoset resin has been introduced into the mould the pad is processed according to the relevant manufacturing method and the resin is allowed to harden, consolidate or cure. After the resin has hardened the pad is ready for assembly.

Pads of the trailer such as the deck and the internal structures may be formed through alternative processes such as continuous manufacturing processes such as pultrusion, extrusion, pull winding, filament winding1 belt pressing, lamination.

At least some of the internal structural elements may be formed from a metallic structure.

Structural elements including, but not only, deck, stringers or bulkheads may also be formed from a sandwich material comprising skins separated by a core preferably the core comprises a lightweight core.

The structural sandwich elements such as bulk-heads could be made to an appropriate shape, or could be formed from a large sheet and then cut to size.

The parts may be joined together by any suitable method including adhesive bonding, welding or by the use of mechanical fasteners.

Any ancillary components may be attached to the resulting trailer.

The invention will now be further described by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic representation of a known 13.6 metre semi-trailer formed generally from metal/metallic materials; Figure 2 is a schematic representation of an underside of the known semi-trailer of Figure 1; Figure 3 is a schematic representation showing hardware that is typically attached to the chassis of a known trailer; Figure 4 is a schematic representation of a steel trailer shown in Figure 1 showing an underside of the trailer; Figure 5 is an exploded perspective view of a trailer according to an embodiment of the invention; Figure 6 is a schematic representation of the trailer of Figure 5 shown in an assembled form; Figure 7 is an exploded cross-sectional representation of the trailer of Figures 5 and 6; Figure 8 is a cross-sectional representation of a second embodiment of a trailer according to the present invention; Figure 9 is a an exploded perspective of a third embodiment of a trailer according to the present invention; Figure 10 is a schematic representation of a fourth embodiment of a trailer io according to the present invention; and Figure 11 is a schematic representation of a fifth embodiment of a trailer according to the present invention.

In order to create a trailer according to embodiments of the invention the inventors is studied the demands and requirements of traditional steel 13.6 metre semi-trailer and used the trailer as a benchmark for developing a composite trailer according to embodiments of the invention.

Referring to Figures 1 and 2 a known steel semi-trailer is designated generally by the reference numeral 2. The semi-trailer 2 comprises two runners 4 extending longitudinally along the length of the semi-trailer 2. The semi-trailer 2 further comprises a plurality of cross members 6 which extend across the semi-trailer 2 generally at right angles to the runners 4. The cross members 6 may be attached to the runners 4 by any convenient means such as by bolting or welding. A floor, or deck may be positioned and/or attached over or between the runners 4 and cross members 6. The deck (not shown) may comprise a plurality of deck sections which may be attached to one another by any convenient means. The deck, runners 4 and members 6 form a chassis 8.

Attached to an underneath surface of the chassis 8, three axles 10, on which are ao mounted three pairs of wheels 12. In other types of semi-trailer, there may be more or fewer axles and wheels.

In the embodiment shown in Figures 1 and 2, the chassis also supports, on an underside, a spare tyre 14.

Turning now to Figure 3, a partial schematic representation of the semi-trailer shown in Figures 1 and 2 is illustrated showing other items of hardware that may be attached to the chassis 8. In this example it can be seen that the chassis supports legs 16 for use when the semi-trailer is not attached to a tow vehicle, side underrun protection device (SUPD) 18, airbags 20, a bulk-head 22, spring arms 24, and rear underrun protection device (RUPD) 26.

It can also be seen that wheel arches 28 may be provided in order to create a tyre clearance above the wheels 12.

The semi-trailer 2 further comprises a king pin 30, which, as is well known in the art, is used to attach the semi-trailer 2 to a tow vehicle in use.

Turning now to Figure 4, a perspective representation of the semi-trailer 2 is depicted.

The representation shows a steel trailer chassis which is shown "upside down" in order to highlight the size of the two main load-bearing I beams.

A trailer such as the type shown in Figure 4 may be regarded as having three main sections along the length of the trailer. The front section as shown in Figure 4 is designated by the reference numeral 32 and a rear section is designated by the reference numeral 36. The rear section has a large depth compared to the front section which has a relatively shallow depth. The rear section provides a structural element to the chassis whilst the shallower front section allows the trailer to be connected to a tractor unit. Between the front section 32 and a rear section 36 is a section known as the gooseneck which is designated by the reference numeral 34. The gooseneck 34 links the front section to the rear section.

Throughout all three sections 32, 341 36, longitudinal rigidity is provided by the runners 4 which may be in the form of I beams.

Longitudinal rigidity is also provided by side raves 38 which may be U shaped.

Since the strength and rigidity of a trailer according to the invention should be at least as good as that of a conventional steel trailer, the inventors analysed the three sections 32, 34, 36. Whilst glass reinforced composite materials have higher specific strength than steel they also have lower specific stiffness. In order that a trailer according to the 3s invention may be retrofitted to standard trailer body boxes and curtain structures, the trailer should have a similar stiffness to that of steel trailers -although it may also be designed to have a lower stiffness and thus take account of the higher specific strength of the composite material and thus reduce weight further.

The inventors considered the demands of a known trailer in order to understand the requirements of a trailer according to embodiments of the invention.

Importantly, the inventors realised that it was not necessary to merely replace the components of a known trailer with similar components formed from a different material.

Instead they redesigned the structure of the trailer so that a lightweight trailer having the required degree of rigidity/flexibility and strength was created from a composite material.

Referring to Figures 5, 6 and 7, a semi-trailer according to an embodiment of the invention is designated generally by the reference numeral 102.

The semi-trailer 102 is formed from a composite material such as glass reinforced plastic (GRP). However any suitable material could be used. As can be seen the trailer comprises a main structural element in the form of a shell 106. The shell 106 comprises a hollow base portion in the form of hull 108, and a lid 110 which comprises deck 112.

The hull 108 has a main portion 114 and peripheral portions 116. In other embodiments.

the shape of the hull 108 may be different but this particular configuration allows clearance for wheels 118, as can be seen particularly in Figure 6.

By forming the trailer as a shell, the trailer is lighter than would be the case with many other configurations.

The main structural element 104 further comprises a spar 120, which in this embodiment is substantially rectangular in cross-section. The spar provides additional strength, stiffness and load transfer to the trailer.

The spar comprises walls 122, 124, which in this embodiment are substantially vertical.

In other embodiments the walls may be orientated at an angle relative to the vertical, which angle is equal to or greater than 0° and less than 90°.

The spar may be formed from any suitable material such as glass reinforced plastic. The fibres of the material forming the spar are orientated at an optimised angle for shear and load transfer.

In this embodiment, the spar also serves as a channel 130 extending along the length of the trailer.

The shell 106 further comprises bulk-heads 126 spaced apart from one another extending transversely and substantially along the length of the trailer. In this embodiment, the bulk-heads extend from a wall 122, 124 of the spar 120, to respective edges of the hull. Different parts of the shell 106 may have different spacings of the bulk heads 126. A front section 32 of the trailer may have bulk-heads positioned more closely together than in the remainder of the trailer, for example.

Further strength, stiffness, buckling resistance, load bearing or load transfer may be provided by positioning one or more longitudinal members 132, known as stringers along the length of the trailer. In the embodiment shown in figure 8, the longitudinal members 132 pass through the bulk heads 126. However other arrangements could also be appropriate.

Turning now to Figure 8 a second embodiment of a trailer according to an aspect of the invention is schematically illustrated in cross-section.

Parts of the trailer 202 shown in Figure 8 that correspond to parts of the trailer 102 shown in Figures 5, 6 and 7 have been given corresponding reference numerals for ease of reference.

In this embodiment, the deck 112 comprises a first deck portion 212 and second deck portion (not shown).

The trailer is formed with a recess 216 formed in the spar 120. The recess is adapted to receive a portion 216 of each of the deck portions 212 in order that each deck portion 212 may fit over the shell 106. The deck portions 212 may have an interference fit with the shell, and/or may be adhesively attached thereto.

In Figure 9, a trailer 502 according to a third embodiment of the invention is shown. In this embodiment, the deck 510 has a contoured surface 504 which in this embodiment comprises castillations 506. The deck is deeper in the direction indicated by the arrow d 3s than is the case in some other embodiments and the castillations or cut outs mean that the overall weight of the deck 510 does not increase, or if it does increase that increase is kept to a minimum. This increase in depth of the deck removes some of the requirements for stringers and reduces the size of bulkheads or removes some of the requirements for bulkheads.

In this embodiment of the invention, the spar 520 is shorter than is the case in some other embodiments, and a central cut out 508 of the deck is shaped to receive the spar 520 when the deck 510 is positioned over the hull.

In Figure 10 part of a trailer 702 according to a seventh embodiment of the invention is illustrated schematically. In this embodiment the shape of the hull 108 has been altered to provide a smoother profile 710. This improves the aerodynamic properties of the trailer 702 and makes it simpler to manufacture by some means.

In Figure 11 part of a trailer 802 according to an eighth embodiment of the invention is illustrated schematically. In this embodiment, the bottom surface of the shell has been raised to form a recess 604 extending into the spar 120. In this embodiment, the lower surface has been raised by approximately 150 mm. Such a structure has found to be less prone to buckling and stiffer in torsion and provides space for location of ancillary equipment.

A trailer according to embodiments of the invention may be made by any convenient method. One appropriate method is to form all the components of the trailer from a polymer composite material, Each component may be formed by placing reinforcing fibres into a mould and then introducing a thermoplastic or thermoset resin into those fibres.

The resin may be introduced into the mould by any convenient means such as by injection, infusion, pre-impregnation or a combination of these methods.

Once the thermoplastic or thermoset resin has been introduced into the mould, the resin should be processed and allowed to harden before the finished component is ready for assembly. The components may be joined together using any suitable means such adhesive bonding, welding and/or the use of mechanical fasteners.

Certain components forming the trailer such as the deck and internal structures such as the channel, bulk-heads etc may be formed using alternative processes such as using continuous manufacturing processes for example pulltrusion, extrusion, pull winding, belt press and filament winding. Some of the components may also be made of other materials such as wood or metal.

Claims

CLAIMS1. A trailer having a semi-monocoque structure.
2. A trailer comprising a shell, which shell forms a primary structural element of the trailer.
3. A trailer according to claim 1 comprising a shell.
4. A trailer according to claim 2 or claim 3 wherein the shell comprises a hull forming a base of the shell, and a deck forming a top portion of the shell.
5. A trailer according to claim 4 wherein the hull comprises a plurality of hull portions.
6. A trailer according to claim 4 or claim S wherein the hull extends longitudinally along some or all of the length of the trailer.
7. A trailer according to any one of the preceding claims comprising a channel or spar extending longitudinally along some or all of the trailer.
8. A trailer according to claim 7 wherein the spar comprises a first lateral wall and a second lateral wall.
9. A trailer according to claim 8 wherein the lateral walls extend vertically.
10. A trailer according to claim 9 wherein the lateral walls extend at an angle of between 15° and 75° to the vertical.
II. A trailer according to any one of the preceding claims comprising one or more stringers extending longitudinally along some or all of the length of the trailer.
12. A trailer according to any one of the preceding claims comprising a plurality of bulk-heads spaced apart along some or all of the length of the trailer.
13. A trailer according to any one of the preceding claims comprising first and second side structures, each of which side structures extend longitudinally along some or all of the length of the trailer.
14. A trailer according to any one of the preceding claims formed from a polymer composite material.
15. A method of manufacturing a trailer comprising the steps of: i) forming a hull; U) forming a deck; Ui) forming one or more further structures providing internal strength, stiffness, buckling resistance or load transfer to the shell; iv) joining together the components to form the trailer.
16. A method according to claim 15 wherein each of the parts forming the trailer is formed from a polymer composite material.
17. A method according to claim 15 or claim 16 in which each of the components forming the trailer is formed by placing reinforcing fibres into a mould and then introducing a thermoplastic or thermoset resin into the fibres.
18. A method according to claim 17 wherein the resin is introduced in to the mould by any one of the following methods: injection; infusion; pre-impregnation or combination.
19. A method according to claim 18 comprising the further step of allowing the resin to harden, consolidate or cure prior to assembling the trailer.
20. A method according to any one of claims 15 to 19 wherein the step of joining together the components forming the trailer comprises adhesively bonding the parts together, welding or mechanical fastening.
21. A trailer substantially as hereinbefore described with reference to the accompanying drawings.
22. A method substantially as hereinbefore described with reference to the accompanying drawings.