US3843182A

US3843182A - Impact cushioning apparatus

Info

Publication number: US3843182A
Application number: US00375542A
Authority: US
Inventors: H Walls; R Mcgaughey
Original assignee: MCCREARY IND PROD CO
Current assignee: MCCREARY IND PROD CO
Priority date: 1972-06-01
Filing date: 1973-07-02
Publication date: 1974-10-22
Anticipated expiration: 1991-10-22

Abstract

An impact cushioning bumper comprises an elongated channelshaped contact member attached at its edges to an elongated mounting member having a face convex-out in cross-section toward the contact member. Within the channel are positioned upright slabs of elastomer which, when the contact member is moved toward the mounting member, are tensioned by stretching over its convex face.

Description

United States Patent 1191 Walls et al. Oct. 22, 1974 IMPACT CUSHIONING APPARATUS 2,829,915 4/1958 75 Inventors: Harold D. Walls; Robert s. McGaughey, both Of White 3:614:148 97 Townshlp, Pa. 3 A M C I d l P d C FOREIGN PATENTS OR APPLICATIONS [7 Sslgnee I gusma l,()35.2l6 8/1953 France 293/71 P n l,264,()76 /!961 Francc 293/71 P [22] Filed: July 2, 1973 Primary ExaminerM. Henson Wood, Jr. [21] Appl 375542 Assistant Examiner-Robcrt Saifer Related US. Application Data Attorney, Agent,-or FirmBuell, Blenko & [63] Continuation-impart of Ser. No. 258,753, June I, Ziescnheim 1972, abandoned, Continuation-impart of Ser. No. 33l,328, Feb. 9, 1973, abandoned [521 US. Cl 293/88 293/72 293/87 impact Cushioning bumper 99111199598 an elongated 6 channel-shaped contact member attached at its edges 51 1111.01. Br 19/10 to an elongated mounting member having a face 5 Field f Search 293/ 71 R, 71 p 72, vex-out in cross-section toward the contact member. 293/84 85 87 88 267/1319 11 40219 Within the channel are positioned upright slabs of elastomer which, when the contact member is moved 5 References Cited toward the mounting member, are tensioned by UMTED STATES PATENTS stretching over its convex face. 2,089,500 8/1937 Ochadloski 293/71 P 21 Claims, 7 ng gures 4 f, 5 ll ds 1o IMPACT CUSHIONING APPARATUS This application is a continuation-in-part of our applications Ser. No. 258,753, filed June l, 1972, now abandoned, and Ser. No. 331,328, filed Feb. 9, 1973, now abandoned, both of which are incorporated by reference herein and made a part hereof.

This invention relates to an impact cushioning apparatus for motor vehicles and the like. It is more particularly concerned with impact cushioning apparatus of that type which utilizes an elastomer for the cushioning agent.

Various types of impact cushioning or absorbing bumpers have been devised using elastomers in compression for the cushioning material. A great disadvantage of bumpers of this type is the limited cushioning effect obtainable in practical designs because of the narrow range through which elastomers can be compressed before failing. For most elastomers failure in compression occurs between about percent and 50 percent deformation and even in the absence of failure the modulus of elasticity increases so rapidly at high deformations that the energy absorbing capacity becomes tively great deflection and so make possible a softer stop. We have found, however, that an elongated bumper utilizing elastomer in tension as its sole or principal energy absorbing medium and which provides a soft stop when it makes contact with a wall or other object which engages it along all or more of its contact face may bottom and so provide a considerably harder stop when it makes contact with a pole or like object which engages only a limited portion of its contact face.

It is an object of our invention therefore to provide an impact cushioning bumper which will more uniformly cushion distributed and localized impacts. It is another object to provide such a bumper in which the principal cushioning agent is an elastomer in tension. It is still another object to provide such a bumper which utilizes as cushioning agent elastomer in tension in combination with pneumatic means. Other objects of our invention will appear in the course of the description thereof which follows.

We have found that we can achieve the objects above mentioned by adjusting the relative dimensions and disposition of certain of the elements of our apparatus and, in certain embodiments, by providing that apparatus with means for maintaining a gas under pressure therein. Our bumper, in its preferred embodiment, comprises an elongated channel-shaped contact member adapted to'receive impact and be moved thereby, a mounting member toward which the contact member is moved, and discrete elements of elastomer spaced lengthwise of the bumper attached at their ends to the contact member and which are stretched when the contact member is moved toward the mounting member. When such a bumper makes contact with an object over only a portion of the bumper length there will inevitably be localized distortion of the'contact member.

If this localized distortion of the contact member tends to reduce the capacityof the elastomer elements to absorb energy by stretching,'the performance of the bumper is impaired. Our bumper to be described hereinafter is designed to minimize this undesirable effect of localized distortion. Embodiments of our invention pres ently preferred by us are illustrated in the attached figures', to which reference is now made.

FIG. I is a perspective, broken away in part, of an article of our invention;

FIG. 2 is a cross-section through the article of FIG. 1 on the plane 22; f

FIG. 3 is a cross-section through the article of FIG. 1 on the same plane as that of FIG. 2 but showing the deformation of the article upon distributed impact with a plane surfaace;

FIG. 4 is a plan, broken away in part, of the article of FIG. 1 but showing the deformation of the article upon localized impact;

FIG. 5 is a perspective of a type of insert used in our invention;

FIG. 6 is a perspective of elements of another embodiment of our invention; and 7 FIG. 7 is a cross-section of that embodiment.

Our article comprises an elongated channel-shaped contact member 1 affixed toan elongated mounting member 5. The web 4 of member 1 is generally convex.- out and the upper and

lower flanges

2 and 3, respectively, diverge from web 4 toward mounting member 5. Web 4 is formed with a centrally located longitudinal corrugation 10 which is concave-out. The

edges

14 and 15 of flanges 2 and3, respectively, terminate in

beads

8 and 9 which are sealed to mounting member 5 by facing member 6 which is elongated likemember 5 and is provided with agroove along each edge into which beads 8 and 9 fit. Facing member 6 is attached to mounting member 5 by bolts 17 which pass through holes in member 5 and are tapped into threaded holes in member 6. The surface 7 of facing member 6 oriented toward contact member 1 is convex-out.

Within contact member 1, which is closed at its ends, are positioned a plurality of upright slabs or panels 11 of elastomer spaced fromeach other and disposed crosswise of contact member .1. These slabs 11 are attached at the tops and bottoms to

flanges

2 and 3, respectively, and at an end to web 4. The other end 12 of the slab stops just short of surface 7 of facing member 6. This end 12 isgenerally plane. The space between successive slabs ll is filled by blocks of foamed elastomer 16. The portion 14 of flange 2 between end 12 of slab 11 and bead 8 has a thickness less than that of the remainder of flange 2 and the corresponding portion 15 of flange 3 likewise has a thickness less than that of the remainder of flange 3. A valve 13 is positioned in flange 2 throughwhich air or other gas may be introduced to increase the pressure within our article above atmospheric pressure. It is convenient to mold contact member l with its thinner extremities l4 and 15, beaded

edges

8 and 9, and enclosed slabs or panels 11 in one piece from an elastomer such as polyurethane.

The operation of our article will be explained in connection with the foregoing description thereof as well as the attached figures. When contact member 1 meets an unyielding object such as a wall, it tends to deform in the manner shown in FIG. 3. The convex web 4 flattens out,

flanges

2 and 3 are forced back toward facing member 6 and their outer edges spread apart, stretching slabs 11 over the convex face 7 of facing member 6. The bulk of the energy of the impact is absorbed by the stretching of the slabs 11 positioned within contact member 1. We have found that when a bumper makes contact with an object over only a portion of the bumper length, as is illustrated in FIG. 4, there is a tendency for the entire bumper to deflect up or down in the area of contact. This probably happens because the bumper rarely meets the object squarely. If the contact member 1 deflects either way, one or the other of its

flanges

2 and 3 is tensioned to some extent but the slabs 11 buckle, and the energy absorbing capacity of the bumper is considerably impaired. We have also found that we can minimize this undesirable tendency by constructing contact member 1 so that

flanges

2 and 3 diverge, as shown in FIG. 2. The distance between them at their outer edges is greater than that at web 4.

A contact member so constructed is much more diffi-- cult to deflect upwardly or downwardly than one having parallel flanges. The stability of the member is sufficient for our purposes if the divergence of the flanges is about one in six, that is to say about one unit measured vertically for each six units measured horizontally from front to back of the bumper.

The energy absorption characteristics of our bumper are also improved if

edge portions

14 and 15 are more flexible than

flanges

2 and 3. This is most easily achieved by

thinningedge portions

14 and 15 of

flanges

2 and 3 as has been mentioned. Those flanges buckle when contact member 1 is forced back toward facing member 6 by an impact. In our bumper this buckling is largely accommodated by outward bulging or folding of

edge portions

14 and 15, as is shown in FIG. 3, which allows the remainder of contact member 1 to move back with less compression than would occur if the buckling were more uniformly distributed. When contact member 1 receives localized impact, as from a pole or the like, a contact member constructed in this way absorbs more energy before bottoming than does a similar bumper with no edge thinning. We find that

edge portions

14 and 15 about l percent to 20 percent thinner than

flanges

2 and 3 provide the benefits above mentioned. v V

Corrugation 10 in web 4 strengthens that web against bending under localized impact and likewise stiffens the slabs or panels 11 and so retards their buckling under those conditions. It is buckling of those slabs, as is'illustrated in FIG. 4, which impairs the energy absorption of the bumper under localized impact and we have found that this buckling is further retarded if the interior of our bumper is filled with a gas, such as air,

at a pressure somewhat above atmospheric pressure.v

For this purpose, valve13 is provided and through it we introduced compressed air or other gas. This compressed air fills the interior of our bumper by flowing freely through the open spaces between the ends 12 of slabs 11 and the convex surface 7 of facing member 6. We believe that when contact member 1 is forced back towards facing member 6 by an impact it further compresses the, air in the bumper, and in regions away from the region of localized impact that compressed air tends to expand contact member 1, thus dissipating the energy of impact by stretching slabs 11 in those regions. We find that a guage pressure on the order of half an atmosphere is sufficient in our article.

The blocks of foamed elastomer 16 which fill the spaces between successive slabs 11 support those slabs against lateral buckling. This action is enhanced by making the blocks 16 of dimensions somewhat greater than those of the spaces to be filled and compressing the blocks when they are inserted. The tendency of the foamed elastomer to expand maintains slabs 11 under tension. For this purpose, we prefer to dimension the blocks 16 with the samewidth and depth as the spaces between slabs 11 but with a height greater than the distance between

flanges

2 and 3. We prefer to make blocks 16 out of foamed polyurethane.

Our invention also comprehends other support meansfor the elastomer slabs. FIG. 5 illustrates an insert I9 conveniently made of a molded elastomer which is inserted in the spaces between the slabs 11. The insert has parallel end walls 20 which have the contour of a cross-section of shell 1 such as is shown in FIG. 2, flat top and bottom walls 21 and a curved front wall 22. The back wall 23 which faces mounting member 5 is planar. and generally rectangular in shape. The insert is provided with a hollow center 24 which opens out of back wall 23, the thickness of the walls so formedv being proportioned to provide the desired amount of support. The slabs 11 may also be supported by sealed cells of a shape similar to that of insert 19 except for the absence of a cavity 24. Those cells are conveniently made of relatively thin elastomer sheet and are sealed so as to formcushions with their contained air or other gas. The cushioning effect of the gas filled cells is-enhanced by disposing within them a foamed elastomer of the type previously mentioned.

A further modification of our invention is illustrated in FIGS. 6 and 7. We have found that it is desirable for some purposes to make the contact member of our bumper of modular units. In this way, bumpers for vehicles of different widthssuch as trucks, buses and pass'enger cars can be made by assembling the appropriate number of identical contact member modules on a mounting member. Twosuch modules 26 are shown side-by-side in FIG. 6. As before, the contact member module has a convex-out web 4 provided with a central concave-out corrugation 10, an upper flange 2, and a lower flange 3, which diverge fromweb 4. Module 26 is closed at each end by a flat wall 27 so that adjacent modules fit closely together.

FIG. 6 also illustrated a modified form of the elastomer slab structure. Vertical slabs or panels 28 spaced from each other are attached along their upper sides to flange 2, along their lower sides to flange 3, and along their front ends to web 4. A horizontal slab 29 is attached at each end to wall 27 of the module and is attached to vertical slabs 28-28 where it intersects them. FIG. 7 shows a module 26 attached to mounting member 5. The

beads

8 and 9 of top and

bottom flanges

2 and 3 are clamped between a tray 30 and a facing member 31. Tray 30 .has a rectangular flat bottom 32 surrounded by an upstanding rim 33 dimensioned to receive module 26. Facing member 31 comprises a rectangular plate 34 sized to fit within tray 30 with clearance all around for the flanges and ends of module 26. All four edges of plate 34 are bent over, as at 37, so as to clear the bead, 8 for example, of the. module flange and clamp it between turned-over edge 37 and the rim 33 of tray 30. The other face of plate 34 is provided with an upstanding rib 35 positioned longitudinally of plate 34 and terminating in a wider member 36 which has a convex-out face toward contact member module 26. Facing member 31 and tray 30 are fastened to mounting member 5 by bolts 17.

The embodiments of our invention illustrated in FIGS. 6 and 7 operate in the same way as those previously described herein. When web 4 of contact member 26 meets an obstacle it is forced back towards member 36.

Flanges

2 and 3 tend to move outwardly from each other and elastomer slabs 28-28 as a result are stretched over the convex surface of member 36. Horizontally positioned slab 29 braces vertical slabs 2828 so as to resist their buckling. Buckling forces transmitted to an end wall 27 of module 26 are resisted by adjoining module 26, where modular units are used. The arrangement of

slabs

28 and 29 shown in FIG. 6 for a modular contact unit 26 is also suitable for a unitary contact member extending the length of the bumper. In both cases, that structure provides improved resistance to localized impact as well as to distributed impact, with less danger of bottoming.

Our module 26 is illustrated as having a dimension greater along the bumper than crosswise of it. Preferably, its dimension crosswise of the bumper would be that appropriatevfor a passenger vehicle. We use the same module for the wider bumpers required for busses, for example, by making the module length equal to the width of a bus bumper and mounting the modules on mounting member 5 with the longer dimension crosswise of the bumper.

Although we have described and illustrated embodiments of our invention in which the energy absorbing elastomer is attached to the impact receiving member, the movement of which stretches the elastomer over the mountingmember, our invention also encompasses the complementary structure in which the elastomer is attached to the mounting member and is stretched over the moving contact member. The mounting member in the embodiments of our invention need not necessarily be a member separate from the vehicle but may be a structural element of the vehicle itself.

In the foregoing description the words top,, bottom," upper, lower, vertical,. vertically, horizontal," horizontally, and upright are used in the context of a conventional bumper positioned crosswise of a vehicle and parallel to the ground.

In the foregoing specification we have described a presently preferred embodiment of this invention, however it will be understood that this invention can be otherwise embodied within the scope of the following claims.

We claim:

1. Impact cushioning apparatus comprising a mounting member adapted to be attached to the article to be cushioned, a contact member adapted to receive impact and be moved toward the mounting member thereby, one of those members being U-shaped in vertical cross section with the open end of the U facing the other member, and elastomeric means interposed be- -tween the contact memberand the mounting member ing, those means comprising a plurality of slabs of elastomer spaced from each other and positioned in planes parallel to saidvertical cross section of theU-shaped member.

2. Apparatus of claim 1 in which the elastomeric means are affixed to the contact member.

3. Apparatus of claim '1 in which the other member is convex in vertical cross section facing the open end of the U.

4. Apparatus of claim 3 in which the face of the mounting member is the convex face.

5. Apparatus of claim 1 in which the members are attached to each other along the edges defined by the open ends of the U-shaped cross section.

6. Apparatus of claim 5 in which the contact member is readily deformable outwardly in planes parallel to its cross-section so that the elastomeric means are stretched by that deformation.

7. Apparatus of claim 5 in which the contact member is channel-shaped having a web with a convex-out impact surface and flanges diverging from the web flat between the web and the edges.

8. Apparatus of claim 7 in which the slabs of elastomer are affixed to the channel-shaped contact member, the flanges of the channel-shaped contact member extend beyond the free edges of the slabs, and the extended portionof the flanges are more flexible than the remaining portion.

9. Apparatus of claim 8 in which the extended portions of the flanges are-thinner than their remaining portions.

10. Apparatus of claim 5 in which the flanges of the channel-shaped contact member are sealed to the mounting member, and including a valve adapted to admit gas under pressure to the interior of the contact member..

11. Apparatus of claim 10 in which the interior of the apparatus is filled with gas at a pressure above atmospheric pressure.

12. Apparatus of claim 11 in which the pressure of the gas is about half an atmosphere.

13. Apparatus of claim 1 in which the free ends of the slabs are spaced from the other member a distance sufficient to provide free flow of gas into and out of a space between'slabs.

14. Apparatus of claim 13 in which the spaces between the plurality of slabs ofela'stomer contain yieldable means for holding those slabs upright.

15. Apparatus of claim 14 in which the yieldable means comprise a foamed compressible material.

16. Apparatus of claim 14 in which the yieldable means comprise a molded elastomer.

17. Apparatus of claim 16 in which the molded elastomer comprises at least one slab of elastomer positioned normal to the other slabs.

l8. -Apparatus" 'of claim 14 in which the yieldable means comprise a gas-filled cell.

19. Apparatus of claim 1 elongated in the direction of the contact surface of the article to be cushioned in which the contact member comprises a plurality of modules positioned adjacent each other along the mounting member, each module having an impactreceiving surface and enclosing a plurality of the slabs of the elastomer and a portion of the other member.

20. Apparatus of claim 19 in which the module is made of an elastomer, is open toward the mounting member with walls adjacent the mounting member formed with a turned-in bead, and including a plate inserted into the module covering the head on all sides,

the plate on itsside away from the mounting member other member is provided with a surface convex-out carrying the portion of the other member, and means only in planes normal to the direction of elongationof fastening the plate to the mounting member. the apparatus. 7 v 21. Apparatus of claim 19 in which the portion of the

Claims

1. Impact cushioning apparatus comprising a mounting member adapted to be attached to the article to be cushioned, a contact member adapted to receive impact and be moved toward the mounting member thereby, one of those members being U-shaped in vertical cross section with the open end of the U facing the other member, and elastomeric means interposed between the contact member and the mounting member and affixed to the U-shaped member so that those means are stretched over the other member by that movement of the contact member towards the mounting member and retard that movement by that stretching, those means comprising a plurality of slabs of elastomer spaced from each other and positioned in planes parallel to said vertical cross section of the U-shaped member.

3. Apparatus of claim 1 in which the other member is convex in vertical cross section facing the open end of the U.

8. Apparatus of claim 7 in which the slabs of elastomer are affixed to the channel-shaped contact member, the flanges of the channel-shaped contact member extend beyond the free edges of the slabs, and the extended portion of the flanges are more flexible than the remaining portion.

9. Apparatus of claim 8 in which the extended portions of the flanges are thinner than their remaining portions.

10. Apparatus of claim 5 in which the flanges of the channel-shaped contact member are sealed to the mounting member, and including a valve adapted to admit gas under pressure to the interior of the contact member.

13. Apparatus of claim 1 in which the free ends of the slabs are spaced from the other member a distance sufficient to provide free flow of gas into and out of a space between slabs.

14. Apparatus of claim 13 in which the spaces between the plurality of slabs of elastomer contain yieldable means for holding those slabs upright.

18. Apparatus of claim 14 in which the yieldable means comprise a gas-filled cell.

19. Apparatus of claim 1 elongated in the direction of the contact surface of the article to be cushioned in which the contact member comprises a plurality of modules positioned adjacent each other along the mounting member, each module having an impact-receiving surface and enclosing a plurality of the slabs of the elastomer and a portion of the other member.

20. Apparatus of claim 19 in which the module is made of an elastomer, is open toward the mounting member with walls adjacent the mounting member formed with a turned-in bead, and including a plate inserted into the module covering the bead on all sides, the plate on its side away from the mounting member carrying the portion of the other member, and means fastening the plate to the mounting member.

21. Apparatus of claim 19 in which the portion of the other member is provided with a surface convex-out only in planes normal to the direction of elongation of the apparatus.