WO2000012357A1

WO2000012357A1 - Device for underrun protection in vehicles

Info

Publication number: WO2000012357A1
Application number: PCT/EP1998/005708
Authority: WO
Inventors: Jörgen HÅKANSSON-BÖKMARK
Original assignee: Volvo Lastvagnar AB
Current assignee: Volvo Truck Corp
Priority date: 1998-08-31
Filing date: 1998-08-31
Publication date: 2000-03-09
Anticipated expiration: 2001-02-28
Also published as: AU9538098A

Abstract

The invention relates to a device for underrun protection in a vehicle (1) comprising an impact element (6) which is arranged on the vehicle (1) in a position which corresponds to the expected impact of a force (F) in the event of a collision, which impact element (6) is connected to a frame (3) forming part of the vehicle (1). The invention is characterized in that said impact element (6) is movably arranged in relation to said frame (3) and adapted so as to assume different positions which define different ground clearances of the impact element (6). By means of the invention, an improved underrun protection device for cargo vehicles is provided.

Description

TITLE: Device for underrun protection in vehicles.

TECHNICAL FIELD:

The present invention relates to a device for underrun protection in vehicles, according to the preamble of appended claim 1. The invention is mainly intended to be applied as an underrun protection devices which can be arranged in a heavy cargo vehicle, for preventing a passenger car from underrunning the cargo vehicle in the event of a collision.

TECHNICAL BACKGROUND:

Large motor vehicles, for example heavy cargo vehicles, are today designed with a relatively high ground clearance. A major reason for this is the need for using the vehicle for driving for example on uneven surfaces. Today's cargo vehicles are normally designed with a ground clearance which is in the order of size of about 40-50 cm at the' front part of the vehicle.

A cargo vehicle is normally provided with a special underrun protection device in the form of a reinforced structure, for example a force-absorbing impact element in the form of a transversal beam. This beam is arranged in the front section of the cargo vehicle, in a position which corresponds to an expected impact due to a force during a collision. Using such an element, it is possible to prevent a passenger car from sliding in under the front of the cargo vehicle in the event of a head-on collision involving the cargo vehicle and the passenger car.

Due to the fact that today's cargo vehicles are often provided with an underrun protection device, it is difficult to meet the above-mentioned demand, i.e. the demand for a high ground clearance so as to facilitate driving in uneven terrain, which for example is a requirement in the case of cargo vehicles for use in construction work. Consequently, a lowering of the ground clearance involves a disadvantage, at least in connection with certain types of cargo vehicles.

A particular problem in the field of underrun protection devices relates to the fact that certain cargo vehicles, in particular cargo vehicles intended for use in construction work, must be able to be used for driving both on ordinary roads and on uneven surfaces. Furthermore, there is today expected legislation defining limit values as regards the highest allowed ground clearance, i.e. the maximum distance allowed from the lower edge of the underrun protection device above the road during normal driving on roads. According to said expected legislation, the ground clearance is limited to 400 mm.

Consequently, there is a problem in certain types of cargo vehicles which must be designed with a relatively low clearance above the road surface during driving on roads, since this limit is not conceived as sufficient, if the same vehicle is to be used for example in construction work, in which a considerably higher ground clearance is normally necessary.

SUMMARY OF THE INVENTION:

The object of the present invention is to provide an improved device for underrun protection in cargo vehicles, in which the above-mentioned problem is solved. This is achieved by means of a device, the characteristic features of which will become obvious from appended claim 1.

The invention intended to be utilized as a device for underrun protection in a vehicle and comprises an impact element which is arranged on the vehicle in a position which corresponds to the expected impact of a force in the event of a collision, which impact element is connected to a frame forming part of the vehicle. The invention is characterized in that said impact element is movably arranged in relation to said frame and adapted so as to assume different positions which define different ground clearances of the impact element.

By means of the invention, an improved underrun protection device is obtained, which device presents at least two conditions having different ground clearance. In this manner, the cargo vehicle can be driven with the impact element in a lower position (with a relatively low ground clearance) on normal roads, and an upper position (with a relatively high ground clearance) during driving for example in uneven terrain.

Additional advantageous embodiments of the invention will become apparent from the subsequent dependent claims.

BRIEF DESCRIPTION OF THE FIGURES:

The invention will in the following be described in greater detail with reference to a preferred embodiment and the appended drawings, where

Fig. 1 is a side view which illustrates in a schematical manner how the present invention can be arranged in a cargo vehicle, and

Fig. 2 is a perspective view which illustrates the essential components according to the invention.

PREFERRED EMBODIMENT:

The present invention constitutes an underrun protection device which in particular is intended for use in cargo vehicles having a relatively high ground clearance. Fig. 1 is a slightly simplified side view illustrating the front section of a cargo vehicle 1, which is provided with the device according to the invention. Fig. 1 also illustrates the front section of a passenger car 2.

In a conventional manner, the cargo vehicle 1 is provided with a frame which in turn comprises two longitudinally arranged frame beams, of which only one frame beam can be seen in Fig. 1. Each frame beam 3 extends essentially in the longitudinal direction of the cargo vehicle 1, up to its front section. According to the preferred embodiment of the invention, two brackets 4 are fixed to the front portion of each frame beam 3. Only one bracket 4 is illustrated in the drawing. Furthermore, a bumper 5 is arranged in a conventional manner, extending horizontally across the front section of the cargo vehicle 1. The bumber

5 is attached to the frame beam 3.

In order to prevent the above-mentioned situation, wherein the car 1 may slide in under the front section of the cargo vehicle 1 in the event of a head-on collision, the cargo vehicle 1 is provided with an underrun protection device. According to the embodiment, the underrun protection device comprises an impact element 6 in the form of a beam having an essentially horizontal extension across the longitudinal direction of the vehicle 1. This transversal beam 6 is preferably manufactured from steel or other suitable material, and presents an essentially rectangular (alternatively square) cross-section. The transversal beam

6 is arranged in the cargo vehicle 1 at a height which corresponds to a certain predetermined ground clearance.

In accordance with the invention, the transversal beam 6 is movably arranged in relation to the above-mentioned frame. In particular, the transversal beam 6 is preferably pivotably arranged in each bracket 4. To this end, the transversal beam 6 is mounted in two link elements 7 (of which only one link element is illustrated in Fig. 1). Each link element 7 is in turn pivotably arranged about a shaft pin 8 which extends through each bracket 4. In this manner, the transversal beam 6 can be pivoted in relation to the frame structure of the cargo vehicle 1, between at least two positions which correspond to different ground clearance. In the lower one of these two positions, the transversal beam 6 is in the position shown by means of continuous lines. In the upper one of the two positions, the transversal beam 6 is in the position shown by means of broken lines and by means of reference numeral 6'.

The ground clearance of the transversal beam 6 can be defined as the distance between the road surface 10 under the vehicle and the underside of the transversal beam 6. According to what has been explained above, this distance must be chosen in accordance with demands as regards passable driving in uneven terrain and also, if applicable, in accordance with prevailing legislation.

When the transversal beam 6 is in its lower position, i.e. below the bracket 4, it presents a ground clearance which is preferably of a magnitude which is less than or equal to 400 mm. As has been mentioned initally, there is in some cases a demand for a considerably higher ground clearance of the cargo vehicle 1. Due to the fact that the transversal beam 6 is pivotably arranged, it can be swung up to its higher position, which is indicated by means of reference numeral 6 ' . During this pivoting movement of the transversal beam, it is pivoted in the forwards direction, i.e. in a direction towards the front section of the cargo vehicle 1. In its simplest form, the swinging movement of the transversal beam can be acheived by manual power, i.e. by bringing it by hand up from the lower position to the upper position. In this condition, the transversal beam 6' can be locked by means of some type of locking mechanism (not shown), for example in the form of a locking pin which is inserted through suitably positioned holes in the bracket 4 and the link element 7 when the transversal beam 6' is in its upper position. In this manner, the transversal beam 6 ' is prevented from swinging back to the lower position due to its own weight.

During driving on roads, the transversal beam 6 is normally in its lower position. In the event of a collision between the cargo vehicle 1 and the car 2, the transversal beam 6 will be acted upon with a very high force F. This force F will be transmitted to each bracket 4, which are intended to absorb this force. In order to limit the pivoting movement of the transversal beam 6 in the rearwards direction, and in order to absorb the force F in an effective manner, each bracket 4 is provided with a stop element 9 in the form of a short rod extending through the bracket 4. This stop element 9 is adapted so as to protrude a short distance from the console 4, in a direction which is essentially parallel to the shaft pin 8. Furthermore, each link element 7 is designed with an upper portion, the movement of which is limited by the stop element 9 in a manner so as to prevent the transversal beam 6 from pivoting too far backwards, i.e. in relation to the front section of the cargo vehicle.

Due to the fact that the transversal beam 6 and the brackets 4 absorb the force F in the event of an impact from the car 2, the car 2 can be prevented from sliding in between the cargo vehicle 1 and the road surface 10. Even when the transversal beam 6' is in its upper position (which by the way is not suitable during driving on roads, since there is a greater risk in this situation that a car will slide in under the front section of the cargo vehicle) it will absorb forces in the event of a collision with an object. Fig. 2 is a perspective view as regarded from behind, at an angle, of the transversal beam 6, which view illustrates the design of the transversal beam 6 and how it can be arranged in the vehicle in question. The drawing illustrates the transversal beam 6 in its lower position. The lower portion of each link element 7 is preferably welded together with a particular bracket element 11. This bracket element 11 is in turn fixed to the transversal beam 6, preferably by means of screw joints. Furthermore, each link element 7 is designed as two identical, plate-like components, between which the shaft pin 8 extends. Furthermore, the shaft pin 8 also extends through the lower portion of each bracket 4, according to what has been explained above.

The mounting of the complete arrangement in the frame beam 3 is carried out by attaching each bracket 4 to the underside of each frame beam 3. This is preferably carried out by means of screw joints.

According to a possible, alternative embodiment of the invention, which is not shown in the drawings, the arrangement with the underrun protection device can be arranged so that it will absorb energy in the event of an impact, for example in the event of a collision with a passenger car. Preferably, this can be achieved by forming each bracket 4 with some type of weakening in its material. During impact with a certain force, the transversal beam 6 will then be acted upon so that energy is transmitted to each bracket 4. Consequently, if the brackets 4 are designed with a weakened portion, this energy can be absorbed as the brackets 4 are deformed and bent backwards. To provide this deformation of the brackets 4 in a controlled manner, the design and positioning of the material weakening must be adapted in accordance with the expected force during impact and the desired progression of the energy absorption. In this manner, the structure will absorb energy in a controlled manner upon impact.

The invention is not limited to the embodiments shown but can be varied within the scope of the claims. For example, the transversal beam 6 can be pivoted to its upper position in more ways than by hand, which has been described above. One possible solution is to use a wire, one end of which is fixed in the transversal beam 6 or the link element 7 and the other end of which can be acted upon by an operator (for exampel the driver, from inside the compartment of the cargo vehicle). In this manner, a remote controlled actuation of the pivoting motion of the transversal beam 6 can be provided. An alternative pivoting mechanism utilizes a hydraulic cylinder which is fixed for example to the frame beam 3 and which comprises a piston rod which is fixed to the transversal beam 6 or the link element 7. This hydraulic cylinder can then be actuated (for example by the driver of the vehicle) for pivoting the transversal beam 6 up and down. A third solution is to use an electric motor which can be arranged in connection to the transversal beam and can be adapted so that it can be actuated for pivoting the transversal beam up and down.

Furthermore, the transversal beam 6 can in principle be adapted so as to be moved between more than two different positions, which correspond to different levels of ground clearance.

Furthermore, the impact element 6 can be movably arranged in other ways than by pivoting it about each shaft pin 8. For example, according to an additional possible solution (which is not shown in the drawings), the impact element can be moved between at least two positions by displacing it up and down in relation to the frame beams 3. To this end, the invention can comprise a telescopic arrangement in which the impact element hangs down from two vertical bars which extend in a telescopic manner inside two tubes, which in turn are fixed to the frame of the cargo vehicle. Alternatively, the impact element can be provided with two horizontally extending pins which are allowed to run up and down along a vertical track in each bracket 4. In the same manner as has been mentioned above, these two alternative embodiments can be provided with means so as to lock the impact element in different assumed positions.

As regards choice of materials, the brackets 4 are preferably made from steel, whereas the impact element 6 is preferably made from steel, aluminium or other suitable material.

Furthermore, the invention may in principle be used as an underrun protection device which is arranged at the rear part of the vehicle or along its sides. Finally, the number of brackets 4 can be more than two.

Claims

CLAIMS :

1. Device for underrun protection in a vehicle (1) comprising an impact element (6) which is arranged on the vehicle (1) in a position which corresponds to the expected impact of a force (F) in the event of a collision, which impact element (6) is connected to a frame (3) forming part of the vehicle (1), c h a r a c t e r i z e d i n that said impact element (6) is movably arranged in relation to said frame (3) and adapted so as to assume different positions which define different ground clearances of the impact element (6).

2. Device according to claim 1, c h a r a c t e r i z e d i n that said impact element (6) is pivotably arranged in relation to said frame (3).

3. Device according to claim 2, c h a r a c t e r i z e d i n that it comprises at least one bracket (4) which is fixed in said frame (3), said bracket (4) comprising a shaft pin (8) defining an axis of rotation about which the impact element (6) can be pivoted.

4. Device according to claim 3, c h a r a c t e r i z e d i n that said axis of rotation extends essentially parallel to the extension of the impact element (6).

5. Device according to any of the preceding claims, c h a r a c t e r i z e d i n that the impact element (6) is mounted in a further bracket (7), which in turn is pivotably arranged about said shaft pin (8).

6. Device according to any of claims 3-5, c h a r a c t e r i z e d i n that said bracket (4) is provided with means (9) for limiting the rotational movement of said impact element (6) about said shaft pin (8).

7. Device according to claims 6, c h a r a c t e r i z e d i n that said means (9) is constituted by a pin which extends from said bracket (4) in a direction which is essentially parallel to said axis of rotation.

8. Device according to any one of the preceding claims, c h a r a c t e r i z e d i n that it comprises means for locking said impact element (6) in at least one of said positions.

9. Device according to any one of the preceding claims, c h a r a c t e r i z e d i n that it comprises means for remote control of the actuation of the impact element (6), for moving it between said positions.