GB2540531A

GB2540531A - Chassis leg member

Info

Publication number: GB2540531A
Application number: GB1509405.5A
Authority: GB
Inventors: Simon Ervin; Quinn John
Original assignee: CHIEFTAIN TRAILERS Ltd
Current assignee: CHIEFTAIN TRAILERS Ltd
Priority date: 2015-06-01
Filing date: 2015-06-01
Publication date: 2017-01-25
Anticipated expiration: 2035-06-01
Also published as: GB2540531B; GB201509405D0

Abstract

A chassis leg 10, particularly for a trailer or a load carrying vehicle such as a truck or a lorry, comprises a pair of spaced apart upper and lower flanges 30, 40 joined between their respective terminal edges along one side by a web having a portion 21 extending inwardly into the space defined between flanges 30, 40. Preferably, inwardly extending portion 21 is a central portion bounded at opposing ends by first and second angled or sloped portions 22a, 22b joined respectively to the upper and lower flanges by first and second shoulders 23a, 23b, with first portion 22a ideally having an angle φ of between 25 degrees and 45 degrees to first shoulder 23a, and second portion 22b ideally having an angle β of between 20 degrees and 40 degrees to second shoulder 23b; first and second portions could be of the same length or of different lengths.

Description

CHASSIS LEG MEMBER Field of the Invention

The present invention relates to chassis leg members for trailers or load carrying vehicles such as, but not limited to, trucks or lorries.

Background to the Invention

Trailers for the transportation of goods and cargo are generally formed of an elongate chassis, having at least one rear axle, usually a number of rear axles, to be pulled by a tractor unit. Wholly or substantially on the trailer chassis is a cargo area for the location of cargo to be transported.

Similarly, load carrying vehicles such as flat bed trucks comprise an elongate chassis having a driver’s cab area at one end and a cargo area extending rearwardly from said cab area.

Generally, such trailers and load carrying vehicles have a chassis comprising a pair of elongate chassis rails or “legs”, which extend generally along the length of the trailer or vehicle. Such elongate chassis rails are commonly an assembly of a number of separate elongate sections which are joined at their respective ends. These elongate chassis rails provide the main load carrying parts of the chassis structure and are commonly formed from I-beam sections. Chassis construction of this type is often referred to as a double I-beam construction. I-beams used for this purpose are commonly welded I-beams whereby the web of the I-beam is welded to the upper and lower flanges of the I-beam.

Even with modern welding processes and using welding robots, the manufacturing times for such I-beam chassis legs can be very long and with high production cost. Furthermore, any problems encountered during the manufacture of these I-beam chassis members can cause significant delays in the construction of trailers or vehicles.

It is therefore an object of the present invention to provide an improved chassis leg member that mitigates the disadvantages of the prior art.

Summary of the Invention

According to a first aspect of the present invention there is provided a chassis leg member comprising a pair of spaced apart upper and lower flanges that are joined between their respective terminal edges along one side by a web, wherein at least a portion of the web extends inwardly into the space defined between the respective spaced apart upper and lower flanges.

Advantageously, the chassis leg member is of a unitary construction formed by folding a metal sheet.

Preferably, the metal is steel.

In this way, the chassis leg member is folded from a sheet of metal to define the spaced apart upper and lower flanges and the web, wherein at least a portion of the web is folded to extend inwardly into the space defined between the respective spaced apart upper and lower flanges.

In this way, the chassis leg member is of one-piece construction.

Preferably, the spaced apart upper and lower flanges are substantially parallel with respect to each other.

Preferably, the at least a portion of the web that is folded to extend inwardly into the space defined between the respective spaced apart upper and lower flanges is a central portion of said web, the central portion being bounded at opposing ends by respective first and second angled or sloped portions, the first angled or sloped portion being joined to the upper flange via a first shoulder portion, and the second angled or sloped portion being joined to the lower flange via a second shoulder portion.

Optionally, the first and second shoulder portions are substantially in alignment with each other. In other words, the first and second shoulder portions lie substantially on the same plane.

Optionally, the central portion is substantially parallel with the first and second shoulder portions.

Optionally, the central portion and the first and second shoulder portions are aligned substantially perpendicular to the respective upper and lower flanges.

Optionally, in one embodiment, the first angled or sloped portion is shorter in length than the second angled or sloped portion.

Optionally, in one embodiment the first angled or sloped portion is longer in length than the second angled or sloped portion.

Optionally, in one embodiment, the first and second angled or sloped portions are equal in length.

Optionally, in an embodiment the height of a chassis leg member in accordance with the invention is around two to four times the length of the upper flange.

Optionally, the length of the central portion is longer than the lengths of the first and second shoulder portions.

Optionally, the depth to which central portion extends inwardly into the space defined between the respective spaced apart upper and lower flanges is approximately the same as, or close to, the lengths of the first and/or second shoulder portions.

Optionally, the angle which the first angled or sloped portion makes with respect to the first shoulder portion is in the range 25-45°.

Optionally, the angle which the second angled or sloped portion makes with respect to the second shoulder portion is in the range 20-40°.

Advantageously, a folded chassis leg member in accordance with the first aspect of the invention may be configured to provide an increased moment of inertia over an I-beam section having the same overall height and width.

Advantageously, the web which extends into the space defined between the respective spaced apart upper and lower flanges and which comprises first and second angled or sloped portions provides a chassis leg member having a shear centre closer to said chassis leg member’s centre of gravity when compared to a “U-section” or “C-section” chassis leg member having the same overall height and width.

In this way, the torsion deformation under loading of a folded chassis leg member in accordance with the invention is reduced in comparison to that of an equivalent ““U-section” or “C-section” chassis leg member having the same section height, width and plate thickness.

Conveniently, the chassis leg member comprises a plurality of cut-out portions, the cut-out portions being adapted to receive cross members that are extensible there through.

Preferably, the cut-out portions are provided though at least a shoulder portion and a sloped or angled portion of the web.

According to a second aspect of the invention there is provided a chassis for a trailer or load carrying vehicle comprising a chassis leg member in accordance with embodiments of the first aspect of the invention.

Preferably, the chassis for a trailer or load carrying vehicle comprises at least a pair of chassis leg members in accordance with embodiments of the first aspect of the invention.

According to a third aspect of the invention there is provided a trailer or load carrying vehicle comprising one or more chassis leg members in accordance with embodiments of the first aspect of the invention.

In one embodiment, the trailer or load carrying vehicle comprises at least two chassis leg members in accordance with embodiments of the first aspect of the invention.

According to a fourth aspect of the present invention there is provided a method of forming a chassis leg member for a trailer or load carrying vehicle, comprising the step forming a single sheet of material by means of folding, wherein the sheet is folded into a shape having a pair of spaced apart upper and lower flanges that are joined between their respective terminal edges along one side by a web, wherein at least a portion of the web extends inwardly into the space defined between the respective spaced apart upper and lower flanges.

Optionally, the method of forming a chassis leg member in accordance with the fourth aspect of the invention includes the step of forming the spaced apart upper and lower flanges such that they are substantially parallel with respect to each other.

Optionally, the method of forming a chassis leg member in accordance with the fourth aspect of the invention includes the step of forming the web to comprise a central portion that is bounded at opposing ends by respective first and second angled or sloped portions, the first angled or sloped portion being joined to the upper flange via a first shoulder portion, and the second angled or sloped portion being joined to the lower flange via a second shoulder portion.

Optionally, the method of forming a chassis leg member in accordance with the fourth aspect of the invention includes the step of forming the first and second shoulder portions so that they are substantially in alignment with each other, i.e. the lie substantially on the same plane.

Optionally, the method of forming a chassis leg member includes the step of forming the central portion so that it is substantially parallel with the first and second shoulder portions.

Optionally, the method of forming a chassis leg member includes the step of forming the central portion and the first and second shoulder portions so that they are aligned substantially perpendicular to the respective upper and lower flanges.

Various examples and aspects of the invention will now be described in detail with reference to the accompanying figures.

Still other aspects, features, and advantages of the present invention are readily apparent from the entire description thereof, including the figures, which illustrate a number of exemplary aspects and implementations. The invention is also capable of other and different aspects and implementations, and its several details can be modified in various respects, all without departing from the present invention.

Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive.

Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes.

It will be appreciated that a chassis leg member in accordance with the first aspect the invention may form a part or section of an overall chassis rail assembly for a chassis having a number of different elongate chassis leg sections joined end to end. For example, a complete chassis rail assembly may comprise a first (e.g. front) section and a second (e.g. a main) section, and/or a third (e.g. an end) section etc., wherein one or more of the constituent sections is a chassis leg member in accordance with the present invention. Accordingly, where the term “a chassis leg member in accordance with the invention” is used herein, it will be appreciated that this is not limited to a chassis leg member of the invention being or comprising a full-length or complete chassis rail on its own, but also includes the case where a chassis leg member of the invention comprises one or more sections or parts of a chassis rail constructed from a number of separate sections.

It will be also be appreciated that the word “trailer” encompasses road and rail trailers.

It will also be appreciated that while the terms “folding” and “folded” are predominantly used herein to describe the method of forming the chassis legs of the present invention, this method is also referred to in the art as “bending” or “sheet metal bending”. Accordingly, the terms “folding” and “folded” are to be understood as referring also to “bending” or otherwise forming by means of a press brake, folder or other similar apparatus.

Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention.

All singular forms of members, or any other components described herein are understood to include plural forms thereof and vice versa.

Brief Description of the Drawings

An embodiment of the present invention will now be described, by way of example only, with reference to the following drawings, in which:

Figure 1 is a cross-section of an exemplary prior art welded I-beam chassis member;

Figures 2a and 2b are cross-section of exemplary chassis leg members according to the present invention;

Figure 3 is a perspective view of an exemplary chassis leg member according to the present invention showing a plurality of cut-out portions provided therethrough; and

Figure 4 is a perspective view of a section of a chassis of a trailer or load carrying vehicle incorporating chassis leg members in accordance with the invention.

Description of the Preferred Embodiments

Referring to the drawings, Figure 1 shows a cross-section of an exemplary prior art welded I-beam chassis member 1 of the prior art, the I-beam comprising a web 2 that is welded between upper 3 and lower flanges 4, the welds 5 extending along the length of the chassis member.

With reference to Figures 2a, 2b, 3 and 4, there is shown a chassis leg member 10 in accordance with the present invention, the chassis member 10 comprising a pair of spaced apart upper 30 and lower 40 in use flanges that are joined between their respective terminal edges 31, 41 along one side by a web 20, wherein at least a portion of the web 20 extends inwardly into the space defined between the respective spaced apart upper and lower flanges, and wherein the chassis leg member 10 is of a unitary construction that is formed by folding a metal sheet.

In this way, the chassis leg member 10 is of one-piece construction, formed by folding a sheet of suitable metal. Preferably, the metal is steel.

An example of the extension of a portion of the web 20 into the space defined between the respective spaced apart upper 30 and lower 40 flanges is indicated schematically by the dimension F in Figures 2a and 2b.

It will be appreciated that the web 20 may take any shape so long as at least a portion thereof extends into the space defined between the respective spaced apart upper 30 and lower 31 flanges. Such a shape may be curved in one or more directions.

In embodiments, the spaced apart upper 30 and lower 40 flanges are substantially parallel with respect to each other.

As shown in detail in Figure 2a, in one embodiment, web 20 comprises a central portion 21 that is bounded at opposing ends by respective first 22a and second 22b angled or sloped portions, the first angled or sloped portion 22a being joined to the upper flange 30 via a first shoulder portion 23a, and the second angled or sloped portion 22b being joined to the lower flange 40 via a second shoulder portion 23b.

In one arrangement, the first 23a and second 23b shoulder portions are substantially in alignment with each other. In other words, first 23a and second 23b shoulder portions lie substantially on the same plane.

As shown in Figure 2a, the central portion 21 may be arranged to be substantially parallel with the first 23a and second 23b shoulder portions.

Optionally, the central portion 21 and the first 23a and second 23b shoulder portions may be aligned substantially perpendicular to the respective upper 30 and lower 40 flanges.

In one embodiment, the first angled or sloped portion 22a is shorter in length than the second angled or sloped portion 22b.

Alternatively, the first angled or sloped portion 22a is longer in length than the second angled or sloped portion 22b.

Alternatively still, the first 22a and second 22b angled or sloped portions may be of equal length.

In Figure 2b there is shown an exemplary chassis leg member cross section 10 in which optional, exemplary dimensions are labelled. Optionally, the material thickness is nominally 8mm. Optionally, the height B of the chassis leg member 10 is around two to four times the length A of upper flange 30. Optionally, the length D of the central portion 21 is longer than the lengths C and/or E of the first 23a and second 23b shoulder portions, respectively. Optionally, the fold depth F is approximately the same as, or close to, the lengths C and/or E of the first 23a and second 23b shoulder portions. Optionally, the angle φ which the first angled or sloped portion makes with respect to the first shoulder portion 23a is in the range 25-45°. Optionally, the angle β which the second angled or sloped portion 22b makes with respect to the second shoulder portion 23b is in the range 20-40°.

It will be appreciated that the precise dimensions of a folded chassis leg member 10 in accordance with the invention may vary depending upon a number of variable factors, including, but not limited to, the expected load limits and/or application in use, the material thickness, the material specification etc.

It is has been found that a chassis leg member in accordance with the invention may be configured to provide an increased moment of inertia over an I-beam section having the same overall height and width.

It has also been found that a chassis leg member 10 having a web 20 which extends into the space defined between the respective spaced apart upper and lower flanges and which comprises first and second angled or sloped portions provides a chassis leg member which has a shear centre closer to said chassis leg member’s centre of gravity when compared to a “U-section” or “C-section” chassis leg member having the same overall height and width and plate thickness. In this way, the torsion under loading of a chassis leg member in accordance with the invention is reduced compared to that of an equivalent ““U-section” or “C-section” chassis leg member.

As shown in Figure 3, a the chassis leg member in accordance with the invention may comprise one or more of cut-out portions 50, 51, the cut-out portions being adapted to receive cross-members 60, 61 that are extensible therethrough to create a chassis structure 100 in accordance with a second aspect of the invention as shown in Figure 4.

One or more cut-out portions 50 may be generally square or rectangular to receive a square or rectangular box-section cross member 60. One or more cut-out portions 51 may be generally l-shaped to receive an l-section cross member 61. The cut-outs conveniently assist with the accurate positioning of the cross members 60, 61, which in turn reduces chassis assembly time. Conveniently, the cut-out portions 50, 51 can be cut from the metal sheet before it is folded into the chassis leg members in accordance with the invention.

Preferably, the cut-out portions 50, 51 are provided though at least the first shoulder portion 23a and the sloped or angled portion 22a of the web 20.

The chassis structure 100 of the second aspect of the invention as shown in Figure 4 comprises two spaced apart chassis leg members 10 between which cross-members 60, 61 extend and to which they are affixed by welding. Cross-members 60, 61 provide additional torsional strength to chassis structure 100, and provide fixing points for ancillary components such as outriggers or deck boards (not shown). Optional, additional sections, for example a box section 63 may be located upon or against one of more of the inner surfaces of a folded chassis leg member 10. In figure 4, such an optional, additional section 63 is shown located abutting the respective inner in use surfaces of lower flange 40 and second shoulder portion 23b.

According to a third aspect of the invention there is also provided a trailer or loadcarrying vehicle (not shown) comprising at least one, and preferably two, chassis members 10 in accordance with embodiments of the first aspect of the invention.

According to a fourth aspect of the present invention not shown in the drawings, there is provided a method of forming of a chassis leg member 10 for a trailer or load carrying vehicle, the method comprising the step of forming a single sheet of material by folding, wherein the sheet is folded into a shape having a pair of spaced apart upper and lower flanges that are joined between their respective terminal edges along one side by a web, wherein at least a portion of the web extends inwardly into the space defined between the respective spaced apart upper and lower flanges.

The method of forming of a chassis leg member may further include the step of forming the spaced apart upper and lower flanges such that they are substantially parallel with respect to each other.

The method of forming of a chassis member by folding may further include the step of forming the web to comprise a central portion that is bounded at opposing ends by respective first and second angled or sloped portions, the first angled or sloped portion being joined to the upper flange via a first shoulder portion, and the second angled or sloped portion being joined to the lower flange via a second shoulder portion.

Folded chassis leg members in accordance with the present invention provide a number of distinct advantages over prior art chassis leg members.

Manufacturing the chassis leg members by folding is both faster and less expensive than the traditional method of producing I-beam members by welding.

Furthermore, the process is reliably repeatable with minimal or no geometric variation between the chassis leg members formed.

In addition, the folded chassis leg members can be made lighter in weight, and the absence of welds provides a longer lifetime and a higher fatigue limit when compared to welded I-beams.

In addition, by forming the chassis leg members by folding, the effects of the heat of the welding process, which can bend the plates of the leg, are obviated. In this way, the absence of heat through welding mitigates against any unwanted deformations in the chassis leg structure during manufacture.

In addition, the amount of welding in a finally assembled chassis leg member is reduced by at least 80% of that required in a typical equivalent welded I-beam chassis leg.

Still furthermore, a range of fold shapes and profiles for chassis leg members can be created with the use of finite element analyses to provide accurate predictions of performance in use. In this way, accurate determination of specific required fold geometries can be obtained for a range of chasses for trailers and load carrying vehicles.

Claims

1. A chassis leg member comprising a pair of spaced apart upper and lower flanges that are joined between their respective terminal edges along one side by a web, wherein at least a portion of the web extends inwardly into the space defined between the respective spaced apart upper and lower flanges.

2. A chassis leg member as claimed in claim 1, wherein the chassis leg member is of a unitary construction formed from a folded metal sheet.

3. A chassis leg member as claimed in claim 1 or claim 2, wherein the spaced apart upper and lower flanges are substantially parallel with respect to each other.

4. A chassis leg member as claimed in any preceding claim, wherein the at least a portion of the web that extends inwardly into the space defined between the respective spaced apart upper and lower flanges is a central portion of said web, the central portion being bounded at opposing ends by respective first and second angled or sloped portions, the first angled or sloped portion being joined to the upper flange via a first shoulder portion, and the second angled or sloped portion being joined to the lower flange via a second shoulder portion.

5. A chassis leg member as claimed in claim 4, wherein the first and second shoulder portions are substantially in alignment with each other.

6. A chassis leg member as claimed in claim 4 or claim 5, wherein the central portion is substantially parallel with the first and second shoulder portions.

7. A chassis leg member as claimed in any one of claims 4 to 6, wherein the central portion and the first and second shoulder portions are aligned substantially perpendicular to the respective upper and lower flanges.

8. A chassis leg member as claimed in any one of claims 4 to 7, wherein the first angled or sloped portion is shorter in length than the second angled or sloped portion.

9. A chassis leg member as claimed in any one of claims 4 to 7, wherein the first angled or sloped portion is longer in length than the second angled or sloped portion.

10. A chassis leg member as claimed in any one of claims 4 to 7, wherein the first and second angled or sloped portions are equal in length.

11. A chassis leg member as claimed in any preceding claim, wherein, the height of the chassis leg member is around two to four times the length of the upper flange.

12. A chassis leg member as claimed in any one of claims 4 to 11, wherein the length of the central portion is longer than the lengths of the first and second shoulder portions.

13. A chassis leg member as claimed in any one of claims 4 to 12, wherein the depth to which central portion extends inwardly into the space defined between the respective spaced apart upper and lower flanges is approximately the same as, or close to, the lengths of the first and/or second shoulder portions.

14. A chassis leg member as claimed in any one of claims 4 to 13, wherein the angle which the first angled or sloped portion makes with respect to the first shoulder portion is in the range 25-45°.

15. A chassis leg member as claimed in any one of claims 4 to 14, wherein the angle which the second angled or sloped portion makes with respect to the second shoulder portion is in the range 20-40°.

16. A chassis leg member as claimed in any preceding claim, wherein the chassis leg member comprises a plurality of cut-out portions, the cut-out portions being adapted to receive cross members that are extensible there through.

17. A chassis leg member as claimed in any one of claims 4 to 15, wherein he chassis leg member comprises a plurality of cut-out portions, said cut-out portions provided though at least a shoulder portion and a sloped or angled portion of the web.

18. A method of forming a chassis leg member for a trailer or load carrying vehicle, the method comprising the step forming a single sheet of material by folding, wherein the sheet is folded into a shape having a pair of spaced apart upper and lower flanges that are joined between their respective terminal edges along one side by a web, wherein at least a portion of the web extends inwardly into the space defined between the respective spaced apart upper and lower flanges.

19. A method of forming a chassis leg member as claimed in claim 18, including the step of forming the spaced apart upper and lower flanges such that they are substantially parallel with respect to each other.

20. A method of forming a chassis leg member as claimed in claim 18 or claim 19, including the step of forming the web to comprise a central portion that is bounded at opposing ends by respective first and second angled or sloped portions, the first angled or sloped portion being joined to the upper flange via a first shoulder portion, and the second angled or sloped portion being joined to the lower flange via a second shoulder portion.

21. A method of forming a chassis leg member as claimed in claim 20, including the step of forming the first and second shoulder portions so that they are substantially in alignment with each other.

22. A method of forming a chassis leg member as claimed in claim 20 or claim 21, including the step of forming the central portion so that it is substantially parallel with the first and second shoulder portions.

23. A method of forming a chassis leg member as claimed in any one of claims 20 to 23, including the step of forming the central portion and the first and second shoulder portions so that they are aligned substantially perpendicular to the respective upper and lower flanges.

24. A chassis for a trailer or load carrying vehicle comprising one or more chassis leg member(s) as claimed in any one of claims 1 to 17.

25. A chassis leg member as substantially herein described with reference to the accompanying drawings Figures 2a to 4.