A metal shearing energy absorber is described. The absorber is composed of a flat thin strip of metal which is pulled through a slot in a cutter member of a metal, harder than the metal of the strip. The slot's length, in the direction perpendicular to the pull direction, is less than the strip's width so that as the strip is pulled through the slot, its edges are sheared off, thereby absorbing some of the pulling energy. In one embodiment the cutter member is a flat plate of steel, while in another embodiment the cutter member is U-shaped with the slot at its base

Fay, R. J.

Wittrock, E. P.

English

NASA Technical Reports Server

REPLY TO
ATTN OF:
\O
O
CO
I
f-
SB
rr! O>
O (TJ
« CN
O r-
O
O
FROM:
M
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
WASHINGTON. D.C. 20546
SEP 0 5 W3
KSI/Scientific & Technical Information Division
Attention: Miss Winnie M. Morgan
GP/Office of Assistant General Counsel for
Patent Matters
SUBJECT? Announcement of NASA-Owned U.S. Patents in STAR
In accordance with the procedures agreed upon by Code GP
and Code KSI, the attached NASA-owned U.S. Patent is being
forwarded for abstracting and announcement in NASA STAR.
The following information is provided:
U.S. Patent No. : J,
Government or
Corporate Employee
Supplementary Corporate
Source (if applicable)
NASA Patent Case No.
NOTE - If this patent covers an invention made by a corporate
employee of a NASA Contractor, the following is applicable:
Yes / j<V No / /
Pursuant to Section 305(a) of the National Aeronautics and
Space Act, the name of the Administrator of NASA appears on
the first page of the patent; however, the name of the actual
inventor (author) appears at the heading of column No. 1 of
the Specification, following the words "... with respect to
an invention of .
Elizabeth A. Carter
Enclosure
Copy of patent cited above
NASA-HQ
https://ntrs.nasa.gov/search.jsp?R=19730021728 2020-03-17T09:09:43+00:00Z
United States Patent
Fletcher et al.
mi 3,749,205
[45] July 31, 1973
I
[54] METAL SHEARING ENERGY ABSORBER
[76] Inventors: James C. Fletcher, Administrator of
the National Aeronautics and Space
Administration with respect to an
invention of; Richard J. Fay;
Edward P. Wittrock, both of Denver,
Colo.
[22] Filed: Dec. 28, 1971
[21] Appl. No.: 212,977
[52] U.S. Cl 188/1 C, 297/386
[51] Int. Cl F16f 7/12
[58] Field of Search 188/1 C; 293/70;
297/386
[56] References Cited
UNITED STATES PATENTS
3,232,383 2/1966 Son Moberg 188/1 C
3,532,380 10/1970 Studer et al 188/1 C UX
FOREIGN PATENTS OR APPLICATIONS
1,105,404 12/1955 France 1.. 188/1 C
Primary Examiner—Duane A. Reger
Attorney—John R. Manning et al.
[57] ABSTRACT
A metal shearing energy absorber is disclosed compris-
ing a flat thin strip of metal which is pulled through a
slot in a cutter member of a metal, harder than the
metal of the strip. The slot's length, in the direction
perpendicular to the pull direction, is less than the
strip's width so that as the strip is pulled through the
slot, its edges are sheared off, thereby absorbing some
of the pulling energy. In one embodiment the cutter
member is a flat plate of steel, while in another embodi-
ment the cutter member is U-shaped, with the slot at its
base.
3 Claims, 6 Drawing Figures
25
PATENTED Jin 31B73 3.749,205
FIG. la
14
t
15
FIG. 3
F I G . I b
.'14 16 10-
FIG. 2
w
i
22 20
14
25
FIG.5
RICHARD J. FAY
EDWARD P. WITTROCK
INVENTORS
ATTORNEYS
3,749,205
1
METAL SHEARING ENERGY ABSORBER
ORIGIN OF INVENTION
The invention described herein was made in the per-
formance of work under a NASA contract and is sub- 5
ject to the provisions of Section 305 of the National
Aeronautics and Space Act of 19S8, Public Law
85-568 (72 Stat. 435; 42 U.S.C. 2457).
BACKGROUND OF THE INVENTION ,0
1. Field of the Invention:
The present invention generally relates to energy ab-
sorbing devices and, more particularly, to a device
which absorbs energy by metal shearing.
2. Description of the Prior Art: 15
There are many applications in which it is necessary
to absorb energy. One example of such an application,
is the seat belt. Various seat belts have been designed
in which the energy is absorbed by shearing off or de-
forming metal strips. Most of the prior art metal shear- 20
ing energy absorbers include a relatively large number
of parts, which increase the cost of manufacturing and
assembly, unnecessarily.
OBJECTS AND SUMMARY OF THE INVENTION
 25
It is a primary object of the present invention to pro-
vide a new metal shearing energy absorber.
Another object of the invention is to provide a novel,
simple, yet highly reliable metal shearing energy ab-
sorber. 30
A further object is to provide a new method of ab-
sorbing energy.
These and other objects of the invention are achieved
by providing a device consisting of a thin strip of metal,
such as aluminum, and a cutting member of a metal, 35
harder than the strip metal, such as steel. The steel cut-
ter is slotted, with the slot length being less than the
strip's width. A leading end of the strip with a width not
more than the slot length is inserted through the slot.
As the strip is pulled through the slot by energy to be
partially absorbed, the edges of the strip, which is wider
than the slot length, are sheared, with energy being dis-
sipated in the shearing of the metal strip. In one em-
bodiment the metal cutter is a flat plate and in another
embodiment the cutter is U-shaped.
The novel features of the invention are set forth with
particularity in the appended claims. The invention will
best be understood from the following description
when read in conjunction with the accompanying draw-
ings. .
45
50
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS, la and Ib are top and side views of one em-
bodiment of a cutter member;
FIG. 2 is a top view of a metal strip of the type shear-
able by the cutter member of FIOS. la and Ib.
FIGS. 3 and 4 are cross-sectional and isometric views
respectively of one embodiment of the invention; and
FIG. 5 is an isometric view of another embodiment
of the invention.
DESCRIPTION OF THE PREFERRED
EMBODIMENTS
60
Attention is first directed to FIGS, la and Ib which
arc top and side views, respectively of a cutter member
in accordance with one embodiment of the invention.
The cutter member 10 is shown consisting of a flat
65
plate 12 of a hard metal, such as steel. A slot 14 extends
through the plate from its top side 15 to the bottom side
16. As shown in FIG. Ib, the slot 14 is preferably
slanted. The length and width of the slot arc designated
by the letters L and T, respectively.
The novel metal shearing energy absorber of the
present invention further includes a thin strip 20,
shown in FIG. 2. Strip 20 is of a metal which is softer
than the metal from which the cutter member 10 is fab-
ricated, for example, aluminum. Strip 20 has a thick-
ness which is not greater than the slot width T and ex-
cept at a leading end 22 its width W is greater than the
slot length L. At the leading end 22 the strip's width is
never greater than L so that this end can be passed
through the slot, as shown in FIG. 3.
In operation as the leading end 22 of strip 20 is pulled
by energy to be partially absorbed, the strip is pulled
through the slot 14. As the strip portion of the width W
is encountered, since L<W, the edges of the strip 20
are sheared off by the slot's edges, thereby reducing the
strip width to L. It is the shearing of the edges of metal
strip 20 which dissipates the energy to be absorbed.
The sheared edges of part of strip 22 arc designated by
numerals 25 in FIG. 4. Therein, the pulling is assumed
to be performed by a pull tab 26 with a slot 27. A
buckle 28 secures the strip leading end 22 to the pull
tab 26. The direction of pull is designated by arrow 30.
From the foregoing it is thus seen that the novel
metal shearing energy absorber of the present inven-
tion consists of a simple slotted cutter. The slot has a
length which is less than the width of a metal strip
which is to be pulled through the slot. By pulling on the
strip its width is reduced to that of the slot length,
which is achieved by the shearing off of the strip's
edges, thereby absorbing the desired energy.
In another embodiment of the invention the cutter
member is U-shaped, as shown in FIG. 5, with the slot
14 being located at the base of the U. Actually this type
cutter member may be formed by drilling a hole at the
center of a flat plate and thereafter bending it into the
U shape. In this version the strip 20 is pulled through
the slot between the two side walls 10a and lOb of the
U-shaped member 10. It should be stressed that in this
embodiment the sheared edges 25 curl or roll up within
the U-shaped member as seen in FIG. 5, thereby fur-
ther absorbing energy by plastic deformation. There-
fore, the widths of the sheared off edges and the radius
of the roll up have to be considered for a particular en-
ergy absorption application.
Although particular embodiments of the invention
have been described and illustrated herein, it is recog-
nized that modifications and variations may readily
occur to those skilled in the art and consequently it is
intended that the claims be interpreted to cover such
modifications and equivalents.
What is claimed is:
1. A metal shearing energy absorber comprising:
a single flat metal plate defining first and second op-
posite flat sides and a slot of preselected length and
width which extends through said plate from said
first side to said second side; and
an elongated strip of a material softer than said plate
and of a thickness not greater than the width of said
slot, said strip having a width, except at a leading
end thereof, which is greater than the slot length,
with the leading end strip width being not more
than the slot length, whereby when said leading end
3,749,205
4
passes through said slot and is pulled away from
said plate, the strip width is reduced at both ends
thereof to equal said slot length, with the ends be-
yond the reduced width being sheared off by said
plate, as said strip is being pulled therethrough. 5
2. The arrangement as recited in claim 1 wherein said
slot is slanted between said first and second sides in the
direction in which said strip is pulled away from the
slot.
3. A metal shearing energy absorber comprising: 10
a U-shaped metal member defining first and second
spaced apart flat walls and a base therebetween
and a rectangularly shaped slot of a preselected
width and length, extending through said base with
the width of said slot extending in a direction per- 15
pendicular to said spaced apart walls;
an elongated rectangularly shaped strip of a material
softer than said member, the strip thickness being
not more than the width of said slot and the strip
width being greater than the slot length, except for
a leading end of said strip which extends out of said
member through said slot, whereby when the strip
leading end is pulled away from said member, the
strip width is reduced at both ends thereof to equal
the slot length, with both ends of the strip beyond
the slot length being sheared off by said member
and tending to curl up between its opposite spaced
apart walls.
20
25
30
35
40
45
50
55
60
65


Metal shearing energy absorber

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server