U.S. patent application number 10/025025 was filed with the patent office on 2003-06-19 for highway crash attenuator frame.
This patent application is currently assigned to Energy Absorption Systems, Inc.. Invention is credited to Cobb, Lincoln C., Welch, James B..
Application Number | 20030113160 10/025025 |
Document ID | / |
Family ID | 21823636 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030113160 |
Kind Code |
A1 |
Welch, James B. ; et
al. |
June 19, 2003 |
HIGHWAY CRASH ATTENUATOR FRAME
Abstract
A highway crash attenuator frame includes transverse elements
that are interconnected by side elements. Each side element is
disposed entirely on a respective side of a central longitudinal
axis of the frame, and one or more tension elements are secured to
the side elements to extend between the side elements across the
longitudinal axis. Each tension element includes a mechanical fuse
operative to fail in tension when the first and second side
elements supply an excessive tensile load to the tension element.
When the mechanical fuse fails in tension in an impact, the side
elements are simultaneously released to move outwardly, away from
the longitudinal axis, and thereby to collapse in a way which is
coordinated between the left and the right sides of the frame.
Inventors: |
Welch, James B.;
(Placerville, CA) ; Cobb, Lincoln C.; (Auburn,
CA) |
Correspondence
Address: |
William A. Webb
Brinks Hofer Gilson & Lione
P.O. Box 10395
Chicago
IL
60610
US
|
Assignee: |
Energy Absorption Systems,
Inc.
|
Family ID: |
21823636 |
Appl. No.: |
10/025025 |
Filed: |
December 19, 2001 |
Current U.S.
Class: |
404/6 |
Current CPC
Class: |
E01F 15/148
20130101 |
Class at
Publication: |
404/6 |
International
Class: |
E01F 013/00; E01F
015/00 |
Claims
1. A highway crash attenuator frame comprising: first and second
transverse elements spaced along a central longitudinal axis; a
first side element extending between the first and second
transverse elements, said first side element disposed entirely on a
first side of the longitudinal axis; a second side element
extending between the first and second transverse elements, said
second side element disposed entirely on a second side of the
longitudinal axis, opposite the first side; a tension element
secured to the first and second side elements and extending between
the first and second side elements across the longitudinal axis,
said tension element comprising a mechanical fuse operative to fail
in tension when the first and second side elements apply an
excessive load to the tension element.
2. The invention of claim 1 further comprising an energy absorber
disposed between the transverse elements and between the side
elements.
3. The invention of claim 1 wherein the side elements each comprise
first and second frames secured together by a set of center hinges,
each first frame secured to the first transverse element by a set
of first hinges, and each second frame secured to the second
transverse element by a set of second hinges.
4. The invention of claim 3 wherein the tension element is secured
to the side elements adjacent to the center hinges.
5. The invention of claim 1 wherein the mechanical fuse comprises
first and second overlapping elements and a shear pin passing
through the overlapping elements.
6. The invention of claim 5 wherein the tension element further
comprises a first cable secured at one end to the first side
element and at an opposite end to the first overlapping element,
and a second cable secured at one end to the second side element
and at an opposite end to the second overlapping element.
7. The invention of claim 6 wherein the cables are oriented
transversely to the shear pin.
8. The invention of claim 1 further comprising: a mounting
arrangement secured to one of the transverse elements and adapted
to mount the crash attenuator frame to a shadow vehicle.
9. The invention of claim 1 further comprising: a third transverse
element; a third side element extending between the second and
third transverse elements, said third side element disposed
entirely on the first side of the longitudinal axis; a fourth side
element extending between the second and third transverse elements,
said fourth side element disposed entirely on the second side of
the longitudinal axis; a second tension element secured to the
third and fourth side elements and extending between the third and
fourth side elements across the longitudinal axis, said second
tension element comprising a second mechanical fuse operative to
fail in tension when the third and fourth side elements apply an
excessive load to the second tension element.
Description
BACKGROUND
[0001] The present invention relates to frames for highway crash
attenuators such as truck mounted attenuators.
[0002] June U.S. Pat. No. 5,642,792 and Leonhardt U.S. Pat. No.
6,092,959 disclose highway crash cushions intended to be mounted on
a shadow vehicle such as a truck. In both cases, the disclosed
crash cushions include frames having transverse elements
interconnected by side elements. The side elements are articulated
such that they can fold outwardly to allow the frame to collapse in
an impact. Premature collapse of the frame is prevented by
restraints coupled to the side elements. In the June patent, these
restraints include diagonally oriented cables extending between the
center portions of the side elements and one of the transverse
elements. These cables prevent the side elements from moving
outwardly until they are released by rotation of pins that secure
the cables to the transverse element. In the Leonhardt patent, the
restraints take the form of bolts secured between adjacent central
portions of the side elements, on either side of the respective
central hinges. The central hinges of the side elements are
prevented from opening until after the bolts have been broken
during an impact.
[0003] Though effective in operation, the diagonal cables of the
June patent may not be optimal for applications that do not use a
probe to initiate collapse of the frame. Because the bolts used to
hold the frame of the Leonhardt patent in the original position are
each responsive only to forces at the respective central hinge, the
opening of the hinges on opposed sides of the frame are not
coordinated with one another.
[0004] Gertz U.S. Pat. No. 5,248,129 describes another frame that
includes a scissors linkage that is held in an initial position by
cables that extend between bars positioned across the frame at the
upper and lower hinges of the linkage. The Gertz patent relates to
a different type of linkage in which rigid bars cross between the
top and the bottom of the frame to form the scissors linkage.
SUMMARY
[0005] By way of general introduction, the highway crash attenuator
frame described below includes one or more tension elements secured
between opposed side elements near the respective central hinges.
Each tension element extends across the longitudinal axis of the
frame, from one side of the frame to the other side of the frame.
Each tension element includes a mechanical fuse that fails in
tension when the first and second side elements of the frame apply
an excessive load to the tension element. Once the mechanical fuse
fails, central hinges on both sides of the frame are simultaneously
allowed to begin opening. In this way, the collapse of the frame is
coordinated between the left and right sides of the frame.
[0006] The foregoing paragraphs have been intended by way of
general introduction, and they are not intended to narrow the scope
of the following claims in any way.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is an isometric view of a highway crash attenuator
frame that incorporates a preferred embodiment of this
invention.
[0008] FIGS. 2 and 3 are enlarged views of the corresponding
encircled regions of FIG. 1.
[0009] FIG. 4 is a top view of a portion of one of the tension
elements of FIG. 1.
DETAILED DESCRIPTION OF THE DRAWINGS
[0010] Turning now to the drawings, FIG. 1 shows a highway crash
attenuator frame 10 that includes first, second and third
transverse elements 12, 14, 16 that are spaced along a central
longitudinal axis L. In this example, the transverse elements are
shown as frames, but in alternative embodiments they may be
implemented as solid panels. In general, the transverse elements
can take many forms, including one-piece elements and assemblies of
component parts.
[0011] The first and second transverse elements 12, 14 are
interconnected by a first side element 18 on a first side of the
central longitudinal axis L and a second side element 20 on a
second, opposed side of the longitudinal axis L. Similarly, the
second and third transverse elements 14, 16 are interconnected by a
third side element 22 positioned entirely on one side of the
longitudinal axis L and a fourth side element 24 positioned
entirely on the opposite side of the longitudinal axis L.
[0012] In this example, the side elements 18, 20, 22, 24 are shown
as articulated frames, but it should be understood that many
alternatives are possible. The side elements may be formed of
panels or individual rods, with or without the hinges described
below. When hinges are used, they can be formed as living hinges or
as multiple-part hinges. In some cases, the side elements may be
rigid rods, bars, or tubes extending between adjacent transverse
elements and shaped to fail in a predictable way during an
impact.
[0013] In the example of FIG. 1, the four side elements 18, 20, 22,
24 are identical, and one of the side elements 18 will be taken as
representative. The side element 18 includes a first frame 26 and a
second frame 28. The first frame 26 is connected by first hinges 30
to the first transverse element 12, and the second frame 28 is
connected by second hinges 32 to the second transverse element 14.
The first and second frames 26, 28 are connected together by center
hinges 34. The hinges 30, 32, 34 are oriented to permit the frames
26, 28 to hinge outwardly (away from the longitudinal axis L) when
the frame 10 collapses in an impact.
[0014] The frame 10 defines first and second bays surrounded by the
transverse elements 12, 14, 16 and the side elements 18, 20, 22,
24. First and second energy absorbers 36, 38 are positioned in the
first and second bays, respectively. When the frame 10 collapses in
an impact, the energy absorbers 36, 38 are axially collapsed,
thereby providing deceleration forces that slow the impacting
vehicle.
[0015] The energy absorbers 36, 38 can take many forms, and the
energy absorbers described in Leonhardt U.S. Pat. No. 6,092,959 can
be taken as examples. It is not required in all embodiments that an
energy absorber be placed within the frame 10, and in some examples
the energy absorbing characteristics of the frame itself are
sufficient to provide the desired decelerating forces.
[0016] In FIG. 1, diagonal cable braces 37 are shown in dotted
lines in order to make FIG. 1 more readable. These diagonal braces
37 improve rigidity of the frame 10 prior to collapse, without
impeding collapse in an impact. Typically, the diagonal braces 37
are formed as flexible cables.
[0017] The first transverse element 12 is secured to a mounting
arrangement 39 that is adapted to cantilever the frame 10 from the
rear of a shadow vehicle such as a truck.
[0018] The elements 12 through 39 described above may take many
forms, and they may, for example, be formed as described in
Leonhardt U.S. Pat. No. 6,092,959, assigned to the assignee of the
present invention and hereby incorporated by reference in its
entirety.
[0019] One important difference between the frame 10 and the frame
shown in the Leonhardt patent relates to the first and second
tension elements 40, 42. Each of the tension elements 40, 42
includes a respective mechanical fuse 44, 46, and the mechanical
fuses 44, 46 hold the respective tension elements 40, 42 intact
until a tensile load is placed on the tensile elements that exceeds
a predetermined threshold value. When this occurs, the mechanical
fuses 44, 46 separate, thereby decoupling the opposed side elements
18, 20; 22, 24.
[0020] The function of the tension elements 40, 42 is to hold the
frame 10 in the position of FIG. 1 until collapsing loads are
applied parallel to the longitudinal axis L in an impact. These
collapsing loads tend to cause the side elements 18, 20, 22, 24 to
bow outwardly (away from the longitudinal axis L) by rotation of
the respective hinges. As long as the tension elements 40, 42 are
intact, they limit the maximum separation between the respective
center hinges 34, and thereby prevent the frame 10 from collapsing.
Once the mechanical fuses 44, 46 separate, the side elements 18, 22
on the first side of the longitudinal axis L are no longer coupled
with the respective side elements 20, 24 on the second side of the
longitudinal axis L, and the side elements are free to move
outwardly. Because the tension elements 40, 42 cross the
longitudinal axis L and are secured between opposed side elements,
the tension elements 40, 42 insure that the side elements on both
sides of the longitudinal axis L are freed to collapse outwardly at
the same instant (within any given bay).
[0021] FIGS. 2 through 4 provide further information regarding the
tension elements 40, 42. In this example, the tension elements 40,
42 are identical, and the following discussion will focus on the
tension element 42.
[0022] As shown in FIG. 2, the tension element 42 includes first
and second cables 48, 50 that are secured at their central ends to
respective overlapping elements 52, 54. The overlapping elements
52, 54 define aligned openings, and a shear pin 56 passes through
the aligned openings. The shear pin 56 in this example is oriented
perpendicularly to the cables 48, 50 and is implemented as a
threaded bolt.
[0023] The outboard ends of the cables 48, 50 terminate in
respective threaded shafts 58. The threaded shafts 58 pass through
openings in flanges 62 secured to the side elements adjacent the
respective center hinges 34. Adjusting nuts 60 are threaded onto
the threaded shafts 58 to adjust the effective lengths of the
cables 48, 50 and therefore of the tension element 42.
[0024] The overlapping elements 52, 54 and the shear pin 56 should
be understood as only one example of a suitable mechanical fuse.
Many alternatives are possible, including mechanical fuses using
two or more shear pins and mechanical fuses using elements designed
to fail in tension rather than in shear. The mechanical fuse can
also be implemented by selecting a cable that parts at a selected
load, a connection between the cable and an attachment element
(such as the threaded shaft 58) that fails at a selected load, or
the like. In this case, the mechanical fuse is integrated into the
tension element, and a single part (e.g. a cable) serves as both
the tension element and as the mechanical fuse. The mechanical
fuses 44, 46 can be designed to separate at the same tensile load,
or at different tensile loads, depending upon the desired mode of
collapse of the frame 10.
[0025] As shown in FIG. 1, tension elements 40, 42 are provided
above and below the respective energy absorbers 36, 48. Thus, there
are two tension elements 40 extending laterally between the side
elements 18, 20, and there are two tension elements 42 extending
laterally between the side elements 22, 24.
[0026] By way of example, the following details of construction are
provided to clearly define the presently preferred embodiment.
These details of construction of course are not intended to limit
the scope of the following claims in any way. In this example, the
first and second cables 48, 50 are implemented as wire rope meeting
federal specification RR-W-410 ({fraction (5/16)} inch diameter,
7.times.19 galvanized). The threaded shaft 58 is 5/8 inch in
diameter, and has 11 threads per inch. The shear pin 56 is a 5/8
inch diameter Grade 2 bolt. The adjusting nuts 60 are tightened to
tension the tension element 40, and thereby to hold the frame 10 in
the position of FIG. 1 prior to an impact. Though FIG. 1 shows
physical structure adjacent the center hinges 38 of the type used
to receive trigger bolts in the above-identified Leonhardt patent,
no trigger bolts are preferably used, and in this example the only
forces holding the center hinges closed are supplied by the tension
elements 40, 42.
[0027] As used herein, the term "set" is intended to mean one or
more. Thus, a set of hinges can include 1, 2, 3 or more hinges. The
term "pin" is intended broadly to encompass rods of various types,
whether threaded or not, and a shear pin may be implemented as a
threaded bolt as described above.
[0028] The foregoing detailed description has discussed only a few
of the many forms that this invention can take. This description is
therefore intended by way of illustration, and not by way of
limitation. It is only the following claims, including all
equivalents, that are intended to define the scope of this
invention.
* * * * *