MOUNTING FOR THE BODY STRUCTURE OF A MOTOR VEHICLE

Abstract: A motor vehicle comprises a chassis (1), a body structure (4) e.g. a tilt-cab, mounted thereon by a bar (10) the bar (10) has a straight central section (12) and forwardly and rearwardly directed radial end sections. The straight section is attached to the chassis (1) by resilient bushes in brackets (19, 20) and the ends of the radial sections are attached to the cab (4) by pivo­ tal bearings housed within the brackets. The bar (10) accom­ modates twisting of the chassis relative to the cab (4), thus reducing stresses in the cab, and also acts in conjunction with the bushes to provide a cab suspension.

Description: This invention relates to motor vehicles especially truck having a chassis and a body structure, such as a cab, mounted thereon. In the case of a truck with a drivers cab, the cab is mounted on the chassis by a front and rear connection. One or both of these comprises two separate transversely-spaced supports which may for example allow the cab to be tilted relative to the chassis, thereby allowing access to parts of the vehicle beneath the cab. One problem which is encountered in the design of suitable connections between the cab and the chassis is that,if the connections are too rigid, the cab is subjected to undesirably high stresses which can damage the structure of the cab. One source of such stress is the twisting of the chassis about its longitudinal axis. This is particulary acute in the case of a body structure secured to the chassis at four points. According to the present invention there is provided a motor vehicle comprising a chassis and a body structure mounted thereon by a bar which is connected to the chassis by two transversely spaced connections and which is connected to the cab by two further transversely spaced connections, the said further connections being respectively off-set in opposite directions from a line joining the connections between the chassis and the bar. Because the connections between the cab and the bar are offset in opposite directions from the line joining the connections between the chassis and the bar, the bar can accommodate twisting movement of the chassis relative to the body structure. Although the invention is especially applicable to the mounting of cabs on motor vehicles such as trucks, it could be applied to any other body structure, for example to van or coach bodies. In the case of a cab,two of the connections between the bar and either the body structure or the chassis may be pivot able to allow the body structure to be tilted relative to the chassis. In order to reduce the transmission of vibrations from the chassis to the body structure, and to damp the movement of the body structure relative to the chassis, the connections between the bar and either the body structure or (preferably) the chassis may include a bush of resiliently deformable material (e.g. rubber). Further, the bar may, if desired, be constructed as a torsion bar so that connection between the body structure and the chassis is sprung. In its simplest form, the bar comprises a straight central section, a radially rearwardly directed section at one end thereof and a radially forwardly directed section at the other end thereof to which the connections to the body structure are preferably attached. With such a construction, compact connections between the chassis and the bar may be formed by a bracket mounted on the chassis, and a bush connecting the bar to the bracket, the rearwardly or forwardly - directed sections of the bar being housed within respective ones of the brackets . In order to allow the ends of the forwardly or rearwardly directed section of the bar to move easily bushes relative to the brackets the / preferably include an aperture. A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a vehicle in accordance with the invention; Figure 2 is a cross section along line Il-Il of Figure 1 on an enlarged scale; Figure 3 is a cross-section along line Ill-Ill of Figure 2 and Figure 4 is a schematic plan of part of the vehicle of Figure 1. Referring to the drawings, a truck comprises a chasis 1 having two longitudinally extending transversely spaced frame members 2,3. A cab 4 is mounted on the chassis 1 by means of two rear transversely spaced mounting brackets (not shown) each of which carries a latch for engaging with a respective keeper 5,6 mounted on the frame members 2,3, as, for example, described in our British Patent Application No. 7920799. At its forward end, the cab 4 is mounted on the chassis 1 by means of a torsion bar 10 extending transversely to the chassis members 2,3. The bar 10 includes a straight central section 12 of square cross-section (fig.1) and, as shown in figures 2Wand 3, the opposite ends of the central cross sqction carry 14 to which are welded a plate sections 15, 16 which respectively extend radially forwardly and rearwardly from the bar 10. The sleeves 14 and the plate section 15,16 are moulded into bushes 17,18 of rubber, or similar resiliently deformable material, which are in turn mounted in brackets 19, 20 secured to respective ones of the chassis members 2,3. The plate sections 15,16 are therefore housed within the brackets 19,20 thus avoiding overhang. The ends of the plate sections 15, 16 are attached to journals 21, 22 in each of which is received a pin 23,24 which are bolted to respective brackets 25,26 on the cab 4. The pins 23,24 are positioned in the journals 21,22 by means of bearing liners 27,28 which allow the pins 23,24 to pivot in the journals 21,22. Thia#allows the cab 4 to be tilted relative to the chassis 1. The bushes 17,18 include apertures 36,37 which allow the journals 21,22 to move freely relative to the brackets 25,26. The operation of the front mounting is shown in Figure 4 which illustrates schematically the relationship between the cab 4, the chasis 1 and the bar 10 and their connections thereto. The two transversely spaced connections 40 41 between the cab 4 and the torsion bar 10, are formed by the cab brackets 25,26, journals 21,22 and pins 23, 24 . The connections 42,43 between the chassis 1 and the bar 10, are formed by the brackets 19,20, and the bushes 17,18. As can be seen in Figure 4 the connections 40,41 are respectively offset in opposite directions (ire. forwardly and rearwardly) from the line joining the other two connections 42f43. Consequently, if one of the connections 42,43 is raised and the other is lowered, as occurs during twisting of the chassis 1 about its longitudinal axis, this movement is accommodated by deflection of the ends of the central section of the bar 10 and rotation of the plate sections 15, 16 relative to the cab brackets 25,26, thus producing no net displacement of the cab 4. The cab 4 is not therefore subjected to stress if the chassis 1 is twisted. Since the bar 10 is also a torsion bar, and is mounted in resilient bushes 17.18 the bar and bushes also provide a sprung connection between the chassis 1 and the cab. Additionally, the bushes 17, 18 serve to damp vibrations transmitted from the chassis 1 to the cab 4.

Claims: CLAIMS. 1. A motor vehicle comprising a chassis and a body structure mounted thereon by a bar which is connected to the chassis by two transversely spaced connections and which is connected to the cab by two further transversely spaced connections, the said further connections being respectively off-set in opposite directions from a line joining the connections between the chassis and the bar. 2. A motor vehicle according to claim 1 wherein the body structure comprises a cab. 3. A motor vehicle according to claim 1 or claim 2 wherein two of the connections between the bar and either the body structure the or/chassi. are pivotable to allow the body structure to be tilted relative to the chassis. 4. A motor vehicle according to any one of claims 1 to 3 wherein the bar comprises a torsion bar. 5. A motor vehicle according to any one of claims 1 to 4 wherein the connections between thebbar and the chassis or the body structure include a bush of resiliently deformable material. 6. A motor vehicle according to any one of claims 1 to 5 wherein the bar comprises a straight central section, a radial rearwardly directed section at one end thereof and a radial forwardly directed section at the other end thereof. 7. A motor vehicle according to claim 6 wherein the connections between the chassis and the bar each comprise a bracket mounted on the chassis, and a bush connecting the bar to the bracket, the rearwardly - and forwardly - directed secticns of the bar being positioned within a respective one of the brackets. 8. A motor vehicle according to claim 7 wherein the bush includes an aperture permitting movement of the ends of the said section relative to the bracket. 9. A motor vehicle according to any one of claims 6 to 8 wherein the ends of the rearwardly - and forwardly - directed sections carry a respective brackets for securing the body structure to the bar. 10. A motor vehicle substantially as hereinbefore described with reference to the drawings.

Inventors: ALLEN, DENIS LYN CRUNDALL
Applicants: FORD FRANCE SOCIETE ANONYME, FORD MOTOR COMPANY LIMITED, FORD-WERKE AKTIENGESELLSCHAFT
Application year: 1981
Main classification: B62D33
IPC codes: B62D33