Method for building a cab for a truck and cab built according to the method, together with system for constructing the cab

TECHNICAL FIELD

The present invention relates to a method for building a cab for a truck according to the preamble of claim 1 below.

The present invention also relates to a cab according to the preamble of claim 3 below.

The present invention also relates to a system for cab construction according to the preamble of claim 5 below.

STATE OF THE ART

In order to be able to produce truck cabs cost- efficiently, various production methods are under continuous development, the trend increasingly being away from the manufacture of a fully assembled cab welded together in one integrated process. EP 0 254 689 Al, for example, discloses the building of a cab, in which fitting of the roof is deferred so as to be able to carry out internal installations via the opening formed at the top, before fitting the roof in the final stage of cab assembly.

Cabs still continue to be built, however, so that each model and size of cab is built using components which are specially intended for a certain cab model and are assembled using a standard technique regardless of which part is to be built or of the relevant production volume.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method, a cab and a system which allow cabs of different models and sizes and intended for different purposes to be built efficiently using standard basic components .

The aforementioned object is achieved by means of the method, the cab and the system according to the invention, the characteristics of which are set forth below in claims 1, 3 and 5 respectively.

DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail on the basis of an exemplary embodiment and with reference to the drawings attached, in which:

Fig. 1 shows a perspective view of a driver's unit, forming part of the cab according to the invention, and

Fig. 2 shows a perspective, exploded view of the main components of a cab according to the invention.

PREFERRED EMBODIMENT The basic unit in the cab system according to the invention consists of a driver's unit 1, which is shown separately in Fig. 1. It is produced separately by conventional high-strength engineering techniques using pressed steel members which are welded together, preferably by means of spot welding to form a safety cage which encloses the driver's seat and the front passenger seat, that is to say the spaces commonly used by persons when driving, which require maximum crash- safety.

In the example the components welded together in the driver's unit 1 comprise a lower and an upper horizontal windshield member 2, 3, which at its ends is welded together with front pillars 4, 5, the so-called

A-pillars, in order to form a rigid framework for the windshield, which at a later stage is fitted in the opening 6, usually by adhesive bonding in order to form an integrated reinforcing part of the safety cage. The front pillars 3, 4 continue without interruption down to a lower front member 7, with which they are welded together. The front section of the driver's unit below the windshield opening, usually referred to as the "fire-wall", has a number of struts, two inclined struts 8, 9, and two vertical struts 10, 11, in the form of short members, which by means of welded joints are connected on the one hand to the lower front member 7 arid on the other to downward extensions 12, 13 of the pillars 4, 5, and to the lower windshield member 2 respectively.

The driver' s unit 1 continues with two side sections 14, 15, which on either side comprise an upper side member 16, 17 and a lower side member 18, 19, which in front are connected by means of welded joints to the upper ends of the front pillars 4, 5 and to their extensions 12, 13 respectively. At the rear the side members 16, 17, 18, 19 are connected to the upper end 20 and the lower end 21 respectively of the middle pillar 22, 23, the so-called B-pillar, thereby enclosing the side openings 24, 25 of the cab, which in the finished cab form door openings, which are closed by the cab doors . Extending along the bottom are longitudinal floor members 26, 27, which at the front are connected by means of welded joints to the lower front member 7. The floor members 26, 27 form load- bearing elements for the cab floor 28, which is welded to the floor members and the lower side members 18, 19, and to the front member 7 and which forms an active, integral part of the driver's unit, that is to say the safety cage. The additionally reinforcing floor extends rearwards right up to the rear edge of the middle pillars 22, 23.

According to the invention the final design of the vehicle cab is determined by a functionally adapted rear additional structure 29 or supplementary part to the driver's unit 1, as can be seen from Fig. 2. This additional structure 29 is built-on behind the driver's unit, which is entirely open at the rear. The additional structure may be provided, through an inventive system of basic components, which can be selected and dimensioned for each individual cab, with a design and/or dimensions specific to each model, size, production volume or purpose.

The additional structure 29 basically comprises horizontal members 30-40 made of metal or any strong polymer, various forms of member joints 41-43 made of metal or a polymer, a number of upright or vertical members 45-48 and a number of covering parts, such as metal cover plates or covering sheets of polymer material . The cover plates or covering sheets may be side sections 49 of various dimensions and these may be solid and fully or partially faced, that is to say they may be designed with fully covering plate or opaque plastics or formed wholly or in part as glazed or plastic windows, which are fixed or capable of opening. The covering parts may be capable of opening on hinges or may take the form of lift-off hatches, or they may be additional doors. One of the covering parts consists of a rear panel 50, whilst another covering part consists of a roof panel 51. The roof panel, in particular, but also the rear panel 50 may be supplied in various shapes and dimensions and different materials, depending on the particular cab model to be built. The material of the various components may be a suitable steel material, for example a steel alloy, lightweight metal, such as aluminum or a suitable aluminum alloy, polymer or partially glazed, as in windows.

In the example shown not only the driver's unit 1, but also the member joints 41-43 may advantageously be manufactured from a high-strength material such as steel and, together with the driver's unit, may form the basic high-volume production components in a basic set, while the remaining components form the model- and volume-specific components. In one embodiment the additional structure 29 is more specifically made up of three horizontal side members 31-35, a lower member 30, 31, a middle member 32, 33 and an upper member 34, 35 on each side, the lower and upper members forming an extension of the upper and lower side members 16-19 respectively of the driver's unit and being welded at their front ends to a fixing surface on each middle pillar 22, 23. The rear ends of the horizontal members are each connected by means of welded joints to member- joints, which may consist of L-joints, T-joints or three-way joints, depending on whether any rear transverse member 40 is to be connected to the rear joint. The example shown features a transverse member which extends between the two upper member joints 43 and is connected at both ends to the member joints by means of welding.

As indicated by dashed lines, the horizontal side members 30-35 may be of a selected length adapted for each model . Either prefabricated members of various lengths are supplied from stock or the members adapted for a particular series are made up from long lengths . Even though the upright members 45-48 in the majority of models may be of unvarying lengths, these can also in principle be of different selected lengths for different cabs. The upright members together with the member joints 41-44 form the rear pillars of the cab, commonly referred to as the C-pillars .

As an alternative, the additional structure may comprise a further extension with horizontal members, which extend the cab rearwards from the member joints

in order to form a storage section, for example, behind the intermediate section thereby created, which may accommodate a rear seat, galley, sleeping berths etc.

When the frame is ready, the covering parts can be fitted using techniques primarily dependent upon the production volume and chosen materials, for example by means of welded, riveted, threaded or adhesive joints.

For mounting the cab on the truck chassis suitable connecting parts are provided, such as brackets 52, 53 which are shown in two alternatives in fig. 2 and are fixed to the lower front member 7, for example. The fixing suitably forms an articulated fixing for sprung rear-edge mounting of the cab. The cab may be either of a conventional type with an engine hood (not shown) in front of the cab or of the cab-over-engine type, which can be tipped for access to the engine beneath.

To sum up, the method for building the truck cab described above comprises a first step which consists of producing the driver's unit 1 by welding, which possibly together with the roof part 51 may be produced in a separate production unit or factory for robot- controlled automated welding and forms a so-called BIW (body-in-white) unit, which undergoes anti-corrosion treatment and paint priming before commencing the next step.

The second step consists of building the additional structure 29, selecting the model-specific member lengths and the covering parts, in addition to the member joints 41-44 needed for assembly. The roof part 51 is primarily selected with a correct dimension for the cab model in question, so that the adjoining edges of the roof coincide with the upper members, to which the roof is to be joined. Roofs may also be selected in order to give cabs different heights and designs, and may be provided with spoilers or equipment for special

vehicles, such as fire engines, for example. The rear section 34 may also be selected for special purposes, such as design or greater cab capacity. The parts are then joined using the model- or volume-specific joining technique, as referred to above.

The invention makes it possible to create a system for building cabs of different models from a limited number of components or modules. In the system the driver's unit forms a standard basic unit for all models whilst the additional structure is specifically put together for each model . This can be chosen from a range of different lengths of frame members 30-40, member joints 41-43 and. covering parts 49-51. Finally the interior fixtures and fittings for the particular model are chosen from a range, depending on a number of factors, such as the size and shape of the cab, standard level, equipment level, climate, function etc.

The facility for deferring the fitting of the roof part 51 and the rear section 34 to a later production stage, as in a final assembly plant, for example, means that the large openings in the cab at the top and rear, which are left open until such time as the roof and the rear section are fitted, can be utilized for an efficient final assembly of the complete cab with all fixtures and fittings in an environment conducive to working. These may include the instrument panel with driver controls, that is to say steering wheel, levers and other controls, seats, panels, galley, sleeping berths etc. The installation can therefore be undertaken from above and/or from the rear by means of robots, which with their arms can reach into the cab interior, lift components in and hold them in position for possibly manual fixing. With regard to the instrument panel, this can alternatively be lifted in from the front through the windshield opening.

The invention is not limited to the examples described above and shown in the drawings, but can be varied without departing from the scope of the following patent claims. For example, the number of frame members both in the driver' s unit and in the additional structure can be varied, two, four or more horizontal side members and a corresponding number of member joints, as well as two, three or more transverse horizontal frame members being feasible, for example. The number of joint intersections is thereby correspondingly varied, that is to say with two or more on each side.