GB2532752A

GB2532752A - Truck

Info

Publication number: GB2532752A
Application number: GB1421009.0A
Authority: GB
Inventors: Horton William; Cresswell Brent; Kelvin Lawton Robert; James Barton Ian
Original assignee: Leyland Trucks Ltd
Current assignee: Leyland Trucks Ltd
Priority date: 2014-11-26
Filing date: 2014-11-26
Publication date: 2016-06-01
Anticipated expiration: 2034-11-26
Also published as: GB2532752B; GB201421009D0

Abstract

A truck chassis frame 1 is provided in first and second frame portions 2, 3. The second frame portion 3 is fixed to the first frame portion 2, so that it is lower to the ground than the first frame portion 2. In this manner, a higher profile of first frame portion 2, which may be because it is made of aluminium rather than steel, does not require that the second frame portion 3 be further raised. In this manner an engine and cab can still be mounted at the same height as previously despite the change in material and profile of the first frame portion 2.

Description

The present invention relates to road going trucks of the type having a cargo carrying region located rearwardly of the driver's cab of the vehicle. The invention is concerned more particularly with such trucks have a rigid chassis so that (in contrast to articulated trucks) there is no articulating movement between the driver's cab and the cargo carrying region of the truck. Such trucks are known in the art as "rigid trucks".

In conventional rigid trucks there is -as indicated above -a rigid chassis. Such a chassis is generally a ladder-frame comprising two steel rails (referred to herein as the primarily rails) which extend lengthwise of the vehicle and which are connected by primary steel cross-members. The primary steel rails are generally of rectangular U-shaped cross-section with the "limbs" of the "U being horizontal (when the truck is on level ground) and being connected by a web lying in a vertical plane.

The engine and the cab of the vehicle (which may be provided over the engine) are located at the front of the vehicle and supported by the primary rails.

The cargo carrying region of the vehicle may, for example, comprise a generally box-like structure with at least a front wall, a roof, a base and rigid or flexible sides (e.g. as in a curtain-sided vehicle), although other formats of cargo carrying region are well known, e.g. a "flat-bed" truck. For the purpose of constructing the cargo carrying region of the vehicle, the general procedure is to secure secondary rails (which are generally also of steel but are sometimes of aluminium or aluminium alloy) to and along the top of the primary rails of the chassis frame, these secondary rails extending from the region of the driver's cab back to the rear of the vehicle. These secondary rails are also of generally rectangular U-shaped construction and are positioned such that their lower limbs are in face-to-face relationship with the upper limbs of the primary rails. Additionally, secondary cross-members (which are generally also of steel but are sometimes of aluminium or aluminium alloy) are then secured to (and on top of) the secondary rails. The secondary rails and secondary cross-members are together known as the "body subframe". The cargo carrying structure is then mounted on the secondary body subframe in a manner well known per se.

Cargo-carrying rigid trucks have been constructed in the above described manner for many years and adequately serve their intended purpose of carrying cargo. There is however a weight disadvantage associated with the extensive use of steel in the chassis itself, the secondary rails and the secondary cross-members. The overall weight of the chassis, secondary rails and cross-members has an adverse impact on the fuel consumption of the vehicle. It will be appreciated that a lower fuel consumption is desirable not only for the purposes of reducing the running costs of the vehicle but also for the purpose of reducing exhaust emissions to address environmental issues.

According to the present invention there is provided a truck comprising a rigid chassis on which are supported an engine, a driver's cab mounted over the engine, and a cargo-carrying region behind the driver's cab, the chassis being comprised of separately formed, first and second chassis frame units rigidly connected together to form the chassis in which the first frame unit supports the cargo carrying region and the second frame unit supports the engine and driver's cab, said first frame unit comprising a pair of transversely spaced, load supporting first rails extending lengthwise of the vehicle with their forward ends located forwardly of the cargo carrying region and rearwardly of the front of the truck, said second frame unit comprising a pair of transversely spaced load-supporting second rails each rigidly connected to a respective one of the first side rails and projecting forwardly therefrom, wherein the second side rails of the second frame unit are each mounted on a respective one of the side rails of the first frame unit below the level of said first rails whereby the second frame unit is at a lower level than the first frame unit.

The load supporting first rails are preferably of aluminium or aluminium alloy but may be of steel.

In the truck of the invention, the depth of the load supporting first rails may correspond to the overall depth of the primary rails, secondary rails and secondary cross-members of a conventional truck (see above discussion). In the case where the load supporting first rails are of aluminium (and therefore replace the primary and secondary steel rails of a conventional chassis) there is a significant weight saving due to the considerably lighter weight of the aluminium or aluminium alloy as compared to steel. The depth of the load supporting rails formed of aluminium or aluminium alloy ensures they have the required strength. In the case where the load supporting rails are of steel, there is also a weight saving since each such rail may be formed as a single component and does not require a lower web of a secondary rail being supported on an upper web of a primary rail (as is the case in a conventional steel chassis), the omission of these two webs serving to provide the weight saving.

By providing, in accordance with the invention, a chassis which is formed as first and second units, it is possible to avoid the need for the (deep) load supporting first rails to extend over the full length of the truck (as do the primary steel rails in the case of a conventional truck). The second frame unit may be located at a height which is the same as that of the primary rails of a conventional steel chassis. Therefore the truck of the invention may make use of components (cab, engine etc.) as currently designed for (and used in the construction of) conventional trucks.

The first frame unit may comprise cross-members connecting the load supporting first rails of the unit, said cross-members preferably also being of aluminium or aluminium alloy. Conveniently, the first frame unit is a ladder-frame.

Additionally, the rails of the second frame unit may also be of aluminium or aluminium alloy, being particularly preferred that these rails are of a cellular construction. The second frame unit may have cross-members connecting the second rails, with these cross members being of aluminium or aluminium alloy.

Thus, in a preferred embodiment of the invention, the chassis of the truck is constructed principally of aluminium or aluminium alloy, with significant weight saving advantage as compared to a conventional steel chassis.

The cargo-carrying region of the truck may have a floor structure comprised of planking elements which are supported directly on the first rails of the first frame unit, so that the floor structure is no higher than the floor of a cargo carrying region of a conventional truck having a steel chassis. For the purpose of constructing such a floor structure, the load supporting side rails (which are preferably of aluminium or aluminium alloy) of the first frame unit may be formed, in the upper region, with a channel-section in which projections provided on a face of the planking elements locate. More specifically, these projections, on any one planking element, are spaced from each other by a distance corresponding to the transverse spacing of the primary rails. The projections and channel sections are configured so that the projections may be located, and retained, in the channel sections, thereby providing a flooring structure supported directly on the primary rails. The planking elements are preferably of aluminium or aluminium alloy.

It will be appreciated from the foregoing disclosure that a preferred embodiment of the invention is a truck in which the chassis (comprised of first and second frame units) may be principally (or wholly) of aluminium or aluminium alloy. Additionally, the cargo-carrying region may have a flooring structure which is also of aluminium or aluminium alloy. Such a truck is of considerably lighter weight than a truck constructed with a conventional steel chassis.

The invention will be further described by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of the chassis for use in constructing one embodiment of truck in accordance with the invention; Fig. 2 is a detail to a much enlarged scale showing the connection between first and second frame units of the chassis shown in Fig. 1; Fig. 3 is a schematic side view of one embodiment of truck in accordance with the invention: and Fig. 4 is a view of a partially assembled truck in accordance with the invention and showing a flooring arrangement for a load-carrying body of the truck.

Fig. 1 illustrates a chassis frame 1 for construction of one embodiment of truck in accordance with the invention. As shown in Fig. 1, chassis frame 1 comprises a first frame unit 2 and a second frame unit 3 rigidly connected to the first frame unit 2. In the assembled truck, the second frame unit 3 is at the front of the vehicle (and as such extends forwardly from frame unit 2) and serves to support the truck's engine and driver's cab, whereas first frame unit 2 extends rearwardly from second frame unit 3 and serves to support a cargo carrying structure of the truck.

Chassis frame units 2 and 3 are both constructed mainly of aluminium to provide an overall lightweight construction for chassis frame 1 and are both ladder-like structures as described more fully below.

First chassis frame unit 2 is constructed of two parallel side rails 4 connected at spaced intervals by cross-members 5, the rails 4 and cross-members 5 both being of aluminium. The rails 4 may, for example, be extruded or pressed components. To ensure the required strength, rails 4 have a depth (i.e. in the height dimension) considerably greater than that of a steel rail used in a conventional ladder-like chassis of a rigid vehicle. The depth of each rail 4 may, for example, be in the region of 400+ cm as compared to 200+ cm for a primary steel rail in a conventional chassis. All other things being equal (wheel size etc) it will be appreciated that upper surface of rails 4 is (in an assembled truck) somewhat higher than would be the upper surface of rails of a conventional steel chassis. . In order to avoid the need for supporting the engine and drivers cab higher than necessary (than would be required if the side rails of first frame unit 2 were continued to the front of the vehicle), the second frame unit (on which the cab and engine are supported) is located at a level lower than first frame unit 2, as clearly seen in Fig. 1.

The cross-sectional shape of side rails 4 is clearly seen in Fig. 2 and is comprised of a web 6 lying in a generally vertical plane (and for the purpose of the following description considered to be formed in upper and lower parts 6u and 61 respectively), a lower horizontal flange 7 extending along the lower edge of web 6 and directed inwardly of the vehicle, and an upper channel section 8. To facilitate manufacture, each rail 4 may be produced from two separate extrusions, namely (i) a first extrusion which provides lower part 61 for the web 6 and which also provides the horizontal flange 7, and (H) a second extrusion which provides upper parts 6u for the web 6 and the channel section 8. The first and second sections may be joined together along the marginal edge regions of web 6u and 61, for which purpose these edge regions may be "feathered" so that when juxtaposed and secured together the resulting joint 9 (illustrated in Fig. 2) is generally of the same thickness as the remainder of web 6. The manufacture of each of the rails 4 as two separate extrusions is, however, purely for convenience to avoid extrusion of each (large) rail 4 as a single component but in principle such single component could be used as the rail Second frame unit 3 is clearly seen in Fig. 1 and comprises two parallel aluminium rails 10 (of the same length as each other but considerably shorter than rails 4) mounted at their rear ends on, and below the level of, the front ends of rails 4. More specifically, the rear end of each rail 10 (of second frame unit 3) is connected to the front end of an associated rail 4 (of the first frame unit 2) by means of a set of three brackets 11 secured, on the one hand, to the outer face of web 6 and, on the other hand, to the upper surface of rail 10. As seen in Fig. 2, each rail 10 is below the level of rail 4 and laterally outboard thereof. Although three (11) have been shown for connecting the rear end of each rail 10 to the front end of a rail 4 it will be appreciated that any number of brackets may be used.

In addition to rails 10, second frame unit 3 comprises an aluminium cross-member 12 located just forwardly of the rails 4, an aluminium FUP (Front Underrun Protection) beam 13 supported below the level of rails 10 by brackets 14, and a tie member 15 supported above the level of rails 10 by the brackets 15.

Rails 10 are produced from cellular, extruded aluminium which (as manufactured) has 6 cells (arranged 3x2) extending along the length of the extrusion. For the purpose of producing rails 10, the cellular extrusion is "machined-down" so that the length of rail 10 forward of cross-member 12 has an array of three cells (i.e. half the original number) -see Fig. 2. FUP beam 13 is a four-cell extruded aluminium beam (e.g. manufactured by "machining-down" a 6-cell beam). Tie member 15 may be of aluminium or alternatively steel.

Reference is now made to Fig. 3 which is a schematic side view of one embodiment of truck 20 in accordance with the invention. As illustrated in Fig. 3, the truck 20 comprises a rigid chassis as described above in relation to Figs. 1 and 2 and is further shown as comprising front wheels 21 associated with suspension units (not shown in Fig. 2) mounted on the rails 10 (of the second fame unit 3), rear wheels 22 mounted on a suspension unit (not illustrated in Fig. 2) supported on the rails 4 (of first frame unit 2). As further shown in Fig. 3, the truck 20 has an engine 23 and drivers cab 24 located above engine 23 and both supported on the second frame unit 3. Additionally, truck 20 has a cargo-carrying body 25 mounted on the rails 4 of first frame unit 2. Given the relatively low height of the second frame unit 3 (as compared to the height of a conventional steel chassis, the truck has independent front suspension, for which purpose each wheel 21 is supported on wishbone units mounted on beam 10. Rear wheels 22 may be the driven wheels and be part of a conventional wheel-and-axle unit mounted on springs supported on rails 4 (of first frame unit 2). An alternative possibility (not illustrated) is the use of air suspension.

In accordance with a preferred feature of the invention, the cargo carrying region 25 has a floor constructed of aluminium planking 26 (see Fig. 4) comprised of individual planking elements 27 supported on the rails 4 (of first frame unit 2). Each planking element 27 is rectangular and has a length greater than the width of first chassis unit 2.

Furthermore, each planking element 27 has, on one face thereof, two projections (not shown) each of which is configured to locate, and be retained in, channel section 8 (see Fig. 2) of the rail 4. The two projections on the face of each planking element 28 are spaced from each other by a distance corresponding to the transverse spacing of the two channel sections 8, whereby each such projection may locate (and be retained) in a respective one of the channel sections 8. Furthermore, side edges of the planking elements 27 are configured so that each planking element 27 may clip to an adjacent such element 27 to form the overall planking structure 26 It will be appreciated that the planking structure is, in effect, "structurally integrated" with the first frame unit 2 and provides a floor (for the cargo-carrying body 25) which is of the same or similar height to the floor of such a body in a vehicle constructed with a conventional steel chassis. Therefore, although rails 4 (of first frame unit 2) are of greater depth than steel rails used in a conventional chassis, there is no loss of cargo-carrying space for a given height of truck.

Overall, the truck is of relatively lightweight construction as compared to one constructed uses a conventional steel chassis, this advantage being obtained by the extensive use of aluminium for the first and second frame units 2 and 3 respectively. Furthermore, in view of the fact that the second frame unit 3 is located at a level lower than the first frame unit 2 (and at a height commensurate with that in a truck constructed with a steel chassis) it is possible for a truck in accordance with the invention to use the same engine and cab as designed for a truck with a steel chassis.

Claims

CLAIMS1. A truck comprising a rigid chassis on which are supported an engine, a driver's cab mounted over the engine, and a cargo-carrying region behind the driver's cab, the chassis being comprised of separately formed, first and second chassis frame units rigidly connected together to form the chassis in which the first frame unit supports the cargo carrying region and the second frame unit supports the engine and driver's cab, said first frame unit comprising a pair of transversely spaced, load supporting first rails extending lengthwise of the vehicle with their forward ends located forwardly of the cargo carrying region and rearwardly of the front of the truck, said second frame unit comprising a pair of transversely spaced load-supporting second rails each rigidly connected to a respective one of the first side rails and projecting forwardly therefrom, wherein the second side rails of the second frame unit are each mounted on a respective one of the side rails of the first frame unit below the level of said first rails whereby the second frame unit is at a lower level than the first frame unit.
2. A truck as claimed in claim 1 wherein the first side rails of the first frame unit are of aluminium or aluminium alloy.
3. A truck as claimed in claim 1 or 2 wherein the first frame unit comprises cross-members connecting the first side rails, said cross members being of aluminium or aluminium alloy or aluminium alloy.

15 20 25
4. A truck as claimed in claim 3 wherein the first frame unit is a ladder-frame.
5. A truck as claimed in any one of claims 1 to 4 wherein the second rails are of aluminium.
6. A truck as claimed in claim 5 wherein the second rails are of cellular construction.
7. A truck as claimed in any one of claims 1 to 6 wherein the second frame unit has cross members connecting said second rails, said cross members being of aluminium or aluminium alloy.
8. A truck as claimed in any one of claims 1 to 7 wherein the first rails are longer than the second rails.
9. A truck as claimed in any one of claims 1 to 8 wherein the cargo-carrying region has a floor structure comprised of planking elements.
10. A truck as claimed in claim 9 wherein the planking elements are of aluminium or aluminium alloy.
11. A truck as claimed in claim 9 or 10 wherein the first side rails are formed, in their upper region, with a channel-section and further wherein the planking elements have on a face thereof projections that locate, and are retained, in the channel sections.