WO2007129959A1

WO2007129959A1 - Arrangement for underrun protection for a vehicle.

Info

Publication number: WO2007129959A1
Application number: PCT/SE2007/000435
Authority: WO
Inventors: Jens Gustafsson; Benny Liljeblad; Tobias VIKSTRÖM; Owe GRANÄNG
Original assignee: Volvo Lastvagnar Ab
Priority date: 2006-05-05
Filing date: 2007-05-04
Publication date: 2007-11-15
Also published as: EP2021210A1; EP2021210A4

Abstract

The invention relates to an underrun protection arrangement (5; 5'; 5') for a vehicle (1) having a frame (3), comprising an impact element (6; 6') connected to the frame (3) and arranged in a position that corresponds to an impact from a force (F) in the event of a collision with another vehicle. The invention is characterized in that said arrangement (5; 5'; 5') furthermore comprises a shell structure (8; 8'; 8') adapted to be removably mounted along said impact element (6; 6'), said impact element (6; 6') thereby defining a base structure supporting said shell structure (8; 8'; 8') and being essentially enclosed by said shell structure (8; 8'; 8').

Description

TITLE:

Arrangement for underrun protection for a vehicle.

TECHNICAL FIELD: The present invention relates to an underrun protection arrangement for a vehicle having a frame, comprising an impact element connected to the frame and arranged in a position that corresponds to an impact from a force in the event of a collision with another vehicle.

STATE OF THE ART:

Larger motor vehicles, such as load-carrying commercial vehicles, are normally designed with relatively high ground clearance. One major reason for this is the need to be able to use the vehicle when driving on uneven ground, for example.

However, the fact that a commercial vehicle normally has a relatively high ground clearance constitutes a serious road safety risk. This is due to the fact that during a collision between the commercial vehicle and a passenger car, there is a risk that the front section of the passenger car will penetrate under the commercial vehicle and thus become wedged between the roadway and the underside of the commercial vehicle. This means that parts of the commercial vehicle may penetrate the passenger compartment of the car with a very high force, which in turn may result in serious injuries to the occupants of the vehicle.

In order to solve the above-mentioned problem, it has been proposed to provide the load-carrying commercial vehicle with a special underrun protection arrangement in the form of a reinforced structure, such as a force resistance beam element. Such an element may be arranged horizontally at . the front end or rear end (or at both ends) of the commercial vehicle. The beam element, or impact element, is then arranged in a position that corresponds to a point of impact from an anticipated force in the event of a collision with a passenger car, i.e. a frontal collision or a rear collision. By means of such an impact element, it is possible to prevent a passenger car penetrating under the commercial vehicle in the event of a collision.

An underrun protection arrangement to be used at the rear side of a vehicle is previously known from the document DE 10330726 A1. This arrangement comprises a tubular protection element which is fixed by means of two sleeve parts in which the tubular element is mounted.

With further reference to a rear underrun protection arrangement, it can be noted that such an arrangement often comprises an impact element which also acts as a support element for carrying certain add-on accessories. For example, such accessories can be in the form of mounting devices for lamps, plates for the registration number of the vehicle, reflex devices and other components.

A rear underrun protection arrangement must also meet legislative demands as regards the impact it must be able to absorb in the event of a collision with a car. Such demands can be defined as a certain static load having a predefined magnitude and acting over certain predefined positions along the impact element.

With regard to prior art, it can be noted that the requirement to provide the impact element with certain add-on components, as explained above, makes it necessary to manufacture different types of impact elements for different vehicle models, since different vehicle models may have different sets of lamps, different placement of number plates etc. It is consequently costly for a vehicle manufacturer to provide different impact elements to different vehicle models. Also, in the event that the impact element is slightly damaged, it may be necessary to replace the entire impact element even though its impact-resistant properties are not affected. Furthermore, due to the fact that the impact element is part of a vehicle's overall design, it is necessary to adapt such design and consequently provide differently designed impact elements for differently designed vehicle models. All these factors lead to an increased cost for manufacturing the impact elements.

Also, in order to provide an impact element in a simple and cost-effective manner, it is normally suitable to use an impact element with a standard, uniform cross section (square or rectangular), which is cost-effective. However, this also results in that the bar may become over-dimensioned in some parts or must be reinforced in some other parts. The impact element is consequently not always designed with the optimal dimensions and geometry.

All the above-mentioned factors add to the cost of manufacturing or repairing the vehicle and the underrun protection arrangement, in particular since changing a complete impact element is costly and time-consuming This is obviously a disadvantage.

SUMMARY OF THE INVENTION:

An object of the present invention is to provide an improved underrun protection arrangement for a load-carrying commercial vehicle, which in particular is used at a rear end section of said commercial vehicle and which overcomes the above-mentioned drawbacks and problems associated with previously known devices.

The above-mentioned object is achieved by means of an arrangement of the type mentioned initially, wherein said arrangement furthermore comprises a shell structure adapted to be removably mounted along said impact element, said impact element thereby defining a base structure supporting said shell structure and being essentially enclosed by said shell structure.

By means of the invention, certain advantages can be obtained. Firstly, it can be noted that due to the fact that the shell structure at least partially covers the impact element, the exterior visible shape of the underrun protection arrangement can be adapted to different truck applications in an easy and cost-effective manner. Also, it is possible to add on different components onto the shell structure without using any particular fastening devices on the impact element. Furthermore, a worn or damaged shell structure is easy to remove and replace with a new shell structure, without having to replace the impact element. Furthermore, the shell structure can be arranged as an energy-absorbing element which may be used in combination with the impact element to absorb a certain load in the event of collision.

Advantageous embodiments of the invention are set out in the dependent claims below.

BRIEF DESCRIPTION OF THE DRAWINGS: The invention will now be described in more detail with reference to a preferred exemplary embodiment and to the drawings attached, in which:

Fig. 1 shows a basic side view of a rear end of a commercial load- carrying vehicle, which is provided with an underrun protection arrangement according to the present invention;

Fig. 2 is a perspective view of an underrun protection arrangement in accordance with a preferred embodiment of the invention;

Fig. 3 is a cross-sectional view of an alternative underrun protection arrangement according to the invention;

Fig. 4a is a cross-sectional view of a further embodiment of the invention, in a first operating condition;

Fig. 4b is a cross-sectional view of the embodiment of Fig. 4a, but in a second operating condition; Fig. 5a shows a side view of an underrun protection arrangement according to an alternative embodiment of the invention; and

Fig. 5b shows a side view of a further alternative embodiment of the invention.

PREFERRED EMBODIMENT:

The invention relates to an underrun protection which is particularly, but not exclusively, intended for load-carrying commercial vehicles with a relatively high ground clearance. Fig. 1 is a somewhat simplified side view showing the rear end of a load-carrying commercial vehicle 1 which is provided with an arrangement according to the invention. Also shown in the figure is an arrow 2 which symbolically indicates a force F which may result from a collision between the vehicle 1 and a conventional passenger car (not shown). It will be seen from the figure that a possible rear collision between a passenger car and the commercial vehicle 1 can lead to the passenger car becoming wedged fast between the commercial vehicle 1 and the roadway, which can lead to serious injuries in particular to occupants of the passenger car. A basic object of the present invention is to prevent such a situation arising.

The commercial vehicle 1 is of conventional construction with a frame, which in turn comprises two longitudinal frame members, only one frame member 3 of which can be seen from Fig. 1. Each frame member 3 extends essentially in the longitudinal direction of the commercial vehicle 1 , up to the rear end section of said vehicle 1. According to a preferred embodiment of the invention, a fastening bracket 4 is fixed to the rear part of each frame member 3, preferably on the lower side of said frame member 3. Only one of these two fastening brackets 4 can be seen from Fig. 1. The brackets 4 are shown in a simplified manner, and it is obvious that such elements can be designed in various ways. In order to prevent the above-mentioned situation in which the passenger car penetrates under the rear of the commercial vehicle 1 in a possible collision straight from the rear, or in an offset collision (the term "offset collision" here referring to a collision in which the longitudinal axis of symmetry of the passenger car is displaced somewhat parallel to the longitudinal axis of symmetry of the commercial vehicle), the commercial vehicle 1 is provided with an underrun protection arrangement 5 which is shown in cross-section in Fig. 1. According to the shown embodiment, this underrun protection arrangement comprises an impact element in the form of a cross-beam 6 extending essentially horizontally and transversely to the longitudinal direction of the commercial vehicle 1 , in the rear section thereof. This crossbeam 6 is preferably made of steel or other suitable material and has an essentially square (or alternatively rectangular) cross-section.

The underrun protection arrangement 5 is furthermore arranged in the commercial vehicle 1 at a height h corresponding to certain predetermined ground clearance, wherein the ground level is indicated with reference numeral 7 in Fig. 1.

According to the invention, the underrun protection arrangement 5 also comprises a shell structure 8 which extends along the longitudinal extension of the cross-beam 6. Also, the shell structure 8 extends generally around the cross-beam 6 so as to enclose or cover said cross-beam 6. As indicated in Fig. 1, the shell structure 8 preferably encloses the rear, top and bottom sides of the cross-beam 6. However, the invention is not limited to this design only, but the shell structure 8 can be varied for example as regards its cross- section and dimensions. A general principle behind the invention is that the shell structure 8 generally defines the outer, visible appearance of the underrun protection device, since it defines a covering element for the cross- beam 6. Also, the shell structure can alternatively be arranged so as to completely enclose or encapsulate the cross-beam 6. The ground clearance 7 of the underrun protection arrangement 5 may suitably be defined as the height h from the underlying roadway to the underside of the shell structure 8, as indicated in Fig. 1. As stated above, this distance must be selected according to the required vehicle accessibility on uneven ground and, where applicable, in accordance with prevailing statutory requirements. For conventional commercial vehicles, the rear ground clearance is normally in the order of less than or equal to 550 mm.

The shell structure 8 is preferably of approximately the same length as the cross-beam 6, although the invention is not limited to such an embodiment only. In other words, the shell structure 8 may be of a different length than the cross-beam 6. An example of such an alternative is that the cross-beam

6 is shorter than the shell structure 8, while still fulfilling the statutory requirement regarding load-absorption in the event of a collision. This means that the complete underrun protection arrangement can be made lighter and more cost-effective in this manner.

Preferably, the cross-beam 6 is fastened to each of the brackets 4 by means of a suitable and conventional fastening method, such as screws, rivets or by means of a welding joint.

An important principle behind the invention is consequently that it combines a base structure (i.e. the cross-beam 6), primarily intended to absorb the force F during a collision, with a completely or partly enclosing shell structure 8 having certain features, as will now be described in detail with reference primarily to Fig. 2.

Fig. 2 is a schematic perspective view showing the underrun protection arrangement 5 with the cross-beam 6 being generally enclosed by the shell structure 8. According to the embodiment, the shell structure 8 comprises a generally plane and vertically extending rear side 8a, a top side 8b and a bottom side 8c. The top side 8b is folded down to define an upper front side 8d, whereas the bottom side 8c is folded up to define a lower front side 8e. All the sides 8a-8e extend in a generally parallel manner with regard to the impact element 6. Furthermore, the upper front side 8d and the lower front side 8e are adapted to function as locking means cooperating with the impact element 6, preferably by being formed as so-called "snap on" locking elements. Such locking means are previously known as such, and for this reason they are not described in detail here. Suitably, the upper front side 8d and the lower front side 8e of the shell structure 8 are of a slightly elastic material so as to allow mounting and the "snap on" function when locking the shell structure 8 to the impact element 6. Such mounting can for example be provided by designing the upper front side 8d and the lower front side 8e with projections which cooperate with locking grooves or tracks provided on the outside of the cross-beam 6.

When the shell structure 8 is mounted on the cross-beam 6, it defines a base structure which both acts as a support for the shell structure 8 and which is also essentially enclosed by said shell structure 8. Also, the shell structure 8 is removably, or detachably, mounted on the cross-beam 6, meaning that the shell structure 8 can be removed and replaced by another shell structure. Such a replacement can be carried out for various reasons. For example, in the event that the shell structure 8 is slightly damaged or worn out, the shell structure 8 can simply be detached from the cross-beam 6 and be replaced with a new shell structure. This means that in the case of a slight damage to the underrun protection arrangement 5, i.e. damage to the outer shell structure 8 only, there is normally no need to replace the entire cross-beam 6. This is an advantage since changing the cross-beam 6 is both time- consuming and costly. Instead, only the shell structure 8 needs to be replaced.

Preferably, the shell structure 8 is provided with fastening means 9 in order to allow certain add-on components to be mounted on the shell structure 8. The fastening means 9 shown in the embodiment of Fig. 2 suitable comprises components for mounting the rear lamps (not shown) of the vehicle and are suitably designed as rectangular recesses in which such rear lamps can be mounted.

The shell structure 8 can alternatively be designed with other types of fastening means (not shown in the drawings) for mounting of add-on components such as registration number plates, reflex devices, mudguards and other components. Also, the shell structure 8 can be designed so as to accommodate ducts for electrical cables, for example for power supply of lamps.

Furthermore, Fig. 2 also describes a further fastening component 10 in the form of a rail having a generally T-shaped cross-section, which can be suitable for certain add-on components, for example lamps, reflex devices and similar components. The fastening rail 10 may extend along a part of the shell structure 8, as shown in Fig. 2, or alternatively along the entire length of the shell structure 8.

A further advantage with the invention is that the shell structure 8 can be adapted to various types of vehicles. This is described with reference to Fig.

3, which shows a particular cross-section design of an underrun protection arrangement 5^' according to the invention. The underrun protection arrangement 5' comprises an impact element 6 of generally the same type as described above with reference to Figs. 1 and 2, but with a shell structure 8' having an outer design which has a generally oval cross-section. In particular, it can be seen that the upper surface of the shell structure 8' is curved, which means that this particular design is suitable for the type of commercial vehicle which is intended for transporting sand and gravel, since it can be expected that sand and similar material will not be collected on a top surface having such a curved design. On the other hand, other types of vehicles intended for other types of use may require another design of the shell structure. In summary, the invention provides an advantage since the shell structure can be adapted to a particular type of vehicle, without having to change the cross-beam. Instead, the cross-beam may be of a standard type having for example a rectangular cross-section which may be used with many types of shell structures.

Another aspect of the invention is that the shell structure 8' may be given a unique shape corresponding to a particular design, brand name or other similar factors. Consequently, by using the invention it is not necessary to adapt the cross-beam to different brands and vehicle designs. It is sufficient to adapt just the shell structure to such chosen design.

Furthermore, Fig. 3 shows a suitably type of "snap-on" mounting of the shell structure 8'. In particular, it can be seen that the front portion of the shell structure 8', shown to the left in Fig. 3 (and consequently facing towards the front of the vehicle), is provided with an edge 11 which extends along generally the entire length of the shell structure 8^'. This edge 11 is adapted for snapping onto the front side 12 of the cross-beam 6 so as to lock the shell structure 8' to the cross-beam 6. For this purpose, the shell structure 8^' is also provided with a generally rectangular section 12 which extends around the outer circumference of the cross-beam 6.

According to a further embodiment, shown in Figs. 4a and 4b, the invention may comprise a shell structure 8^" which is arranged with energy-absorbing properties. With reference initially to Fig. 4a, it can be noted that such a shell structure 8" is provided with a rear side 13 being designed to absorb a certain force F in the event of a rear collision with a car. Analogous with the above-mentioned embodiments, the shell structure 8" is arranged to at least partly enclose the cross-beam 6'. Fig. 4b shows an arrangement corresponding to Fig. 4a, but in a first operating condition during a collision, wherein a large force F is actually acting upon the underrun protection arrangement 5". In the event of such a collision between the commercial vehicle and a passenger car, the force F will be partly absorbed by the rear side 13 of the shell structure 8". Suitably, the rear side 13 is arranged to be deformed in a controlled manner in the event that the force F which is generated during a collision exceeds a predetermined threshold value.

Consequently, according to this embodiment, the shell structure 8^" is formed with an integrated energy-absorbing element in the form of the rear side 13 for providing absorption of energy in the event of impact during a collision. This is shown in Fig. 4b, which indicates how the force F generated during a collision makes the rear side 13 yield and be deformed. According to the embodiment, the shell structure 8^" is designed with dimensions, form and material which is adapted for absorbing a predefined and suitable amount of energy during such a collision.

Figs. 4a and 4b also show an alternative type of "snap-on" mounting, wherein the cross-beam 6^' comprises a top side 14 and a bottom side 15 which is provided with grooves 16, 17. These grooves 16, 17 are arranged to cooperate with corresponding ribs 18, 19, i.e. longitudinal protrusions, on the inside of the shell structure 8". In this manner, the shell structure 8^" can be mounted in a simply but effective manner on the cross-beam 6^'.

Figs. 5a and 5b show a further important principle behind the present invention. As indicated in Fig. 5a, the vehicle frame 3 can be said to be arranged with a given height over the ground level 7, i.e. a particular distance Hi from the ground level 7 and up to the frame 3. Furthermore, according to this embodiment, the underrun protection arrangement 5 is arranged so that the shell structure 8 can be positioned in a vertically adjustable manner. In other words, the shell structure 8 may assume a position which can be adjusted in the vertical direction with respect to the cross-beam 6.

In Fig. 5a, the shell structure 8 is positioned at a relatively high position in relation to the cross-beam 6. On the other hand, in Fig. 5b the shell structure 8 is shown in a relatively low position with respect to the cross-beam 6. The purpose of this vertically adjustable positioning of the shell structure 8 is the requirement to maintain a relatively constant ground clearance from the ground level 7 and up to the underrun protection arrangement 5, i.e. a relatively constant distance hi from the ground level 7 and up to the lower side of the shell structure 8, as indicated in Figs. 5a and 5b. In particular, it can be noted from Fig. 5b that the ground clearance hi as measured from the ground level 7 and up to the lower side of the shell structure 8 can be kept constant even though the actual height of the vehicle frame 3 varies. The embodiment shown in Fig. 5b has a distance hfe from the ground level 7 to the frame 3 which is greater than the corresponding distance Hi as indicated in Fig. 5a. However, even though the distance H₂ from the ground level 7 to the frame 3 is greater in Fig. 5b than in Fig. 5a, the ground clearance hi from the ground level 7 and up to the lower side of the shell structure 8 is maintained at a constant value h-i, which is due to the vertical displacement of the shell structure 8.

In summary, a basic principle of the invention is that the above-described shell structure is adapted as a cover which essentially encloses the cross- beam. Suitably, the shell structure is removably mounted along the crossbeam. The cross-beam defines a base structure which supports the shell structure and which is essentially enclosed by the shell structure. The crossbeam can be manufactured as a standard component having a uniform cross section, and only the shell structure needs to be specially adapted to the particular vehicle in which it is used. The invention is not limited to the embodiment described above, but may be modified without departing from the scope of the claims below. For example, the invention can in principle be used in all types of vehicle such as trucks, loaders and busses, in which a relatively high ground clearance is desirable. The invention is therefore not limited to use in commercial vehicles of the type described above.

The invention can furthermore in principle be used as an underrun protection that is arranged on the rear end section of a vehicle or along the sides thereof. Finally, the front brackets 4 (cf. Fig. 1) may be two or more in number.

With regard to the choice of material, the cross-beam 6 can be made of steel, aluminium or other suitable material. Also, in order to lock the shell structure onto the cross-beam, other types of locking means and fastening devices than the above-mentioned snap-on devices can be used.

Claims

1. Underrun protection arrangement (5; 5'; 5") for a vehicle (1) having a frame (3), comprising an impact element (6; 6') connected to the frame (3) and arranged in a position that corresponds to an impact from a force (F) in the event of a collision with another vehicle, characterized in that said arrangement (5; 5^'; 5") furthermore comprises a shell structure (8; 8'; 8") adapted to be removably mounted along said impact element (6; 6'), said impact element (6; 6^') thereby defining a base structure supporting said shell structure (8; 8'; 8") and being essentially enclosed by said shell structure (8; 8^'; 8^").

2. Arrangement (5) according to claim ^characterized in that said shell structure (8) comprises fastening means (9, 10) adapted for mounting accessories such as lamps, registration number plates, reflex devices or similar add-on devices.

3. Arrangement (5; 5'; 5") according to claim 1 or 2, characterized i n that the shell structure (8; 8'; 8") is provided with snap-on locking means

(11; 18, 19) for locking said shell structure (8; 8^'; 8") onto said impact element (6; 6').

4. Arrangement (5") according to any one of the preceding claims, cha racterized i n that the shell structure (8^") is formed with an integrated energy-absorbing element (13) for providing absorption of energy in the event of impact (F).

5. Arrangement (5") according to claim 4, characterized in that said energy-absorbing element (13) is arranged to be deformed in the event that a force (F) which acts on said shell structure (8^") during said collision exceeds a predetermined threshold value.

6. Arrangement according to any one of the preceding claims, characterized in that said impact element (6) and said shell structure

(8) is arranged generally transverse to the longitudinal direction of the vehicle

(1).

7. Arrangement according to any one of claims 1-5, characterized in that said impact element (6) and said shell structure (8) is arranged to be positioned generally along the sides of said vehicle.

8. Arrangement according to any one of the preceding claims, characterized in that said shell structure (8) is adapted for vertical displacement with respect to said impact element (6), in order to maintain a predetermined ground clearance (hi) from the ground level (7) and up to the underrun protection arrangement (5).

9. Arrangement according to any one of the preceding claims, ch a racterized i n that it comprises two connecting elements (4) connecting the impact element (6) to the frame (3).

10. Vehicle comprising an underrun protection arrangement (5; 5^'; 5") according to any or the preceding claims.