GB2032052A

GB2032052A - A bumper structure which allows for thermal expansion of an energy-absorbing member thereof

Info

Publication number: GB2032052A
Application number: GB7930978A
Authority: GB
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1978-09-06
Filing date: 1979-09-06
Publication date: 1980-04-30
Also published as: GB2032052B; DE2936086A1; FR2435374B1; DE2936086C2; JPS5537740U; FR2435374A1

Abstract

A bumper structure is disclosed in which an energy-absorbing member (30) which forms the body of a bumper (20) is mounted on bumper stays (60), which are in turn fixed to a vehicle, by fasteners (70, 72) which pass through apertures (66a, 66b) (32a, 34a) in the stays and the energy-absorbing member, at least one of each pair of corresponding apertures (32a, 34a) in the stays and the energy-absorbing member being formed as a slot elongated in the longitudinal direction of the bumper, so as to allow the energy-absorbing member, when it becomes heated, to expand in its longitudinal direction and to move against a certain sliding resistance relative to the stays. Optionally, collars (50, 52) may be fitted in these slots. <IMAGE>

Description

SPECIFICATION A bumper structure which allows for thermal expansion of an energy-absorbing member thereof The present invention relates to a bumper structure, and more particularly to a bumper structure which allows for thermal expansion of an energy-absorbing member which is incorporated therein.

Fig. 1 of the accompanying drawings shows a cross-sectional view of a prior art elongated bumper structure, 10, in which an energyabsorbing member 1 2 formed of synthetic resin, rubber, or the like is supported on a pair of mounting stay members 14 spaced along the energy-absorbing member. Each mounting stay member 14 has a stem portion 14a and an end portion 1 4b which is substantially enlarged in the vertical direction. The end portion 1 4b is bolted at its upper and lower flanges 14c and 1 4do upper and lower arms 1 2a and 1 2b of the energyabsorbing member by bolts and nuts 1 6 and 1 8 which are passed through circular holes in the upper and lower flanges and the upper and lower arms.

However, the material of the energy-absorbing member has a rather high coefficient of thermal expansion, which is much larger than that of a metal bumper, and problems have arisen in very hot and/or very cold countries, with regard to thermal expansion and contraction of the energyabsorbing member. It has been found that the expansion and contraction of this member have sometimes proceeded so far as to buckle and crack the bumper.

Further, the construction of the conventional mounting stay member outlined above entails a large amount of waste metal, owing to the enlarged shape of the end thereof.

Therefore, it is an object of the present invention to provide a bumper structure which is capable of absorbing thermal expansion and contraction. It is a further object of the present invention to provide a bumper structure in which the mounting stays can be constructed without much wastage of metal, in line with resource conservation, which is becoming more and more important nowadays.

According to the present invention, these and other objects are attained by a bumper structure for a vehicle, comprising: a) an elongated energyabsorbing member whose cross-section includes two substantially parallel legs, the parts of the energy-absorbing member whose cross-sections are the legs each having a plurality of first apertures; b) a plurality of mounting members spaced along the energy-absorbing member for mounting it on the vehicie, each being elongated, and its one end portion being fitted between the parts of the energy-absorbing member whose cross-sections are the legs, said end portion having on its upper and lower portions two second apertures, each of which corresponds to one of the first apertures, one of this pair of first and second apertures being elongated in the lengthwise direction of the energy-absorbing member; and c) a plurality of fasteners, each extending through a pair of first and second apertures and connecting said energy-absorbing member and a said mounting member so as to allow said energyabsorbing member to move somewhat in its lengthwise direction relative to said mounting member against a certain sliding resistance.

In the accompanying drawings: Fig. 1 is a cross-sectional view of a prior art bumper structure; Fig. 2 is a perspective view of a preferred embodiment of a bumper structure according to the present invention, having mounting stay members, one of which is shown as separated for the purposes of illustration; Fig. 3 is a cross-sectional view, similar to Fig. 1, taken along the line Ill-Ill in Fig. 2; Fig. 4 is a cross-sectional view taken along line lV-IV in Fig. 3; and Fig. 5 is a view, similar to Figs. 1 and 3, of a second embodiment of the present invention.

Referring to Figs. 2, 3 and 4 of the drawings, there is shown a preferred embodiment of the bumper structure of the present invention, generally designated 20. This bumper structure comprises an elongated energy-absorbing member 30 made of synthetic resin, rubber, or the like, whose cross-section has two legs 32 and 34.

A metallic ornamental finisher member 40 is mounted on the upper side of the upper leg 32.

The lower leg 34 extends generally parallel to the upper leg 32 and below this leg 34 extends a lower finisher part 36 of the bumper.

In the legs 32 and 34 are provided a plurality of slots 32a and 34a, extending in the longitudinal direction of the bumper, one slot in each leg corresponding to each mounting stay member 60 (to be described later). In these slots 32a and 34a are fitted respectively a collar 50 and a flanged collar 52, which can slide in the lengthwise direction along the slots, against a certain sliding resistance. The ornamental finisher member 40 is provided with circular holes 40a, corresponding to the slots 32a in the upper leg 32.

In the shown embodiment of the bumper structure, two mounting stay members 60 are provided, although in other embodiments different numbers thereof might be provided. Each stay member 60 has a stem portion 62 of substantially U-shaped cross-section and an end portion 64 which is also substantially U-shaped, and which is slightly iarger in the vertical direction than the stem portion, but not substantially larger. Thereby the stay member 60 can be formed out of one piece of metal with minimum waste. The stem portions 62 are fixed to the body of the vehicle, which is not shown. The end portions 64 are each inserted between the upper and lower legs 32 and 34, and each end portion 64 has upper and lower holes 66a and 66b which are generally circular in shape, formed in upper and lower flanges (both designated by reference numeral 66) at the upper and lower sides of the end portion 64.The upper hole 66a corresponds to one of the slots 32a fitted with a collar 50, and the lower hole 66b corresponds to one of the slots 34a fitted with a collar 52. Through the hole 40a, the slot 32a, the collar 50, and the hole 66a is fitted the ornamental bolt and nut 70, and through the slot 34a, the collar 52, and the hole 66b is fitted a bolt and nut 72. Thereby the energy-absorbing member 20 is connected to the stay members 60 so as to be able to slide along its lengthwise direction within the length of the slots 32a, 34a, against a certain sliding resistance, by the sliding of the collars 50, 52 in the slots 32a, 34a.

In other embodiments, the slots could be provided in the stay members, instead of in the energy-absorbing member; this is within the scope of the present invention. Further, in the shown embodiment, it may be noticed that no provision is made for allowing take-up of thermal expansion of the ornamental finisher 40, since the holes 40a therein are circular. This is because the thermal coefficient of expansion of metal, as stated above, is less than that of the material of the energyabsorbing member, and hence the problem is not as severe.

Fig. 5 shows a second embodiment of the present invention, generally designated by 200. In this case, the top finisher member 400 is mounted on a separate leg 320 of the cross-section of the energy-absorbing member 300. The configuration of the mounting legs of the cross-section of the energy-absorbing member, which are designated by 340 and 360, is slightly different, as seen in the figure. The mounting structure between these legs and the stay member is similar, except that both the upper and the lower sliding collar 520 and 540 are flanged and that bolt and nut assemblies 720 and 740 are of an ordinary type in this case.

Based on the foregoing disclosure, it will be easily apparent how this structure is formed. Other reference characters not referred to in this specifications but shown in Fig. 5, except for reference characters 360a which denote the through hole in the leg 360, respectively, designate parts and portions corresponding to those shown by similar reference characters in Fig.

3 which are bigger by one figure (zero) than those in Fig. 5.

Thereby it is seen that the presently proposed bumper structure allows for thermal expansion and contraction of the energy-absorbing member, by the sliding of the collars in the slots.

However, the collars are not essential, although they are preferred. Therefore, the present invention should not be considered as limited to the shown embodiments thereof, however, or mere and simple generalizations, or other detailed embodiments.

Claims

1. A bumper structure for a vehicle, comprising: a) an elongated energy-absorbing member whose cross-section includes two substantially parallel legs, the parts of the energy-absorbing member whose cross-sections are the legs each having a plurality of first apertures; b) a plurality of mounting members spaced along the energy-absorbing member for mounting it on the vehicle, each being elongated and its one end portion being fitted between the parts of the energy-absorbing member whose cross-sections are the legs, said end portion having on its upper and lower portions two second apertures, each of which corresponds to one of the first apertures, one of this pair of first and second apertures being elongated in the lengthwise direction of the energy-absorbing member; and c) a plurality of fasteners, each extending through a pair of first and second apertures and connecting said energy-absorbing member and a said mounting member so as to allow said energy absorbing member to move somewhat in its lengthwise direction relative to said mounting member against a certain sliding resistance.

2. The bumper structure as claimed in claim 1, wherein said one end portion of each of said mounting members is not substantially larger in withe vertical direction than the rest of said mounting member.

3. The bumper structure as claimed in claim 1, wherein each of said fasteners is a bolt and nut assembly.

4. The bumper structure as claimed in claim 1, further comprising a collar corresponding to each of the fasteners, and fitted over it through its first aperture.

5. The bumper structure as claimed in any of claims 1 to 4, wherein the first apertures are elongated, and the second apertures are substantially circular

6. The bumper structure as claimed in any of claims 1 to 4, wherein the first apertures are substantially circular, and the second apertures are elongated.

7. A bumper structure for a vehicle substantially as described with reference to, and as illustrated in, Figs. 2 to 4, or Fig. 5, of the accompanying drawings.