SHOCK ABSORBING STRUCTURAL MEMBER William J. De Gain, Detroit, Mich., assignor to Koppy Tool Corporation, Ferntlale, Mich., a corporation of Michigan
Filed July 14, 1966, Ser. No. 565,223
10 Claims. (CI. 74—492)
ABSTRACT OF THE DISCLOSURE
A structural member which is adapted to remain rigid when subjected to forces below a predetermined magnitude and to collapse and absorb energy when forces in excess of the predetermined magnitude are imposed on it, is formed of sheet steel and has an elongated tubular configuration. A series of regularly spaced radial rings of reduced thickness are disposed along the length of the tube and the tube is bent at the rings so that alternate rings are expanded to a larger diameter than the intermediate rings. Longitudinal slits or cut-outs extend across the outwardly expanded tube sections. The member is made by successively forming bends of decreased thicknesses at regular intervals along the tube; forming the slits, and outwardly expanding intermediate bands.
This invention relates to a shock absorber that structurally supports a substantial predetermined load and collapses to a predictable configuration when overloaded and more particularly to the use of shock absorbers to reduce the force of impact in a collision.
It is often desirable, such as when used in vehicles, that shock absorbers carry a portion of the structural load prior to impact.
It is an object of this invention to provide a structural stress carrying element that substantially rigidly supports a predetermined load prior to impact or collision, and after such impact, foreshortens a considerable distance in collapse.
It is another object of this invention to provide a structural load carrying element that carries a predetermined load prior to impact of collision, and collapses a considerable distance that is predetermined after such impact, and is readily detachable and disposable after the collision.
It is a further object of this invention to provide a structural stress carrying element in the structure of a vehicle that carries a predetermined load prior to impact of collision, collapses to a predictable length and configuration after collision, limits the transmission of deceleration forces caused by collision during collapse, is readily detachable and disposable after collision, and is capable of being easily and inexpensively manufactured while having an uncomplicated design.
It is a still further object of this invention to provide an uncomplicated and inexpensive method of making a structural element that is capable of carrying a predetermined structural load prior to impact, that collapses to a predetermined configuration after the impact of collision, and is readily removable and disposable after collision.
These and other objects are accomplished by a tubular structure having circumferentially aligned depressed grooves at uniform intervals on its exterior surface. Longitudinal openings formed are coaxially arrayed between certain of these grooves and across others. Every other groove is expanded outwardly from a central axis of the tubular structure. This expansion forms barrel-like portions that render a predetermined configuration of collapse of the tube when a sufficient axially directed load is applied to the tube. The openings or grooves provide a precisely predetermined thickness of a tubular structure
where there is a minimum thickness of the structure. This predetermined minimum thickness together with the precise pattern and initial collapse configuration provides both the load carrying capabilities and predictable collapse configuration of the structural element.
Other objections of this invention will appear in the following description and appended claims, referring to the accompanying drawing forming a part of the specification.
In the drawings:
FIGURE 1 is a perspective view of a structural member of a preferred embodiment of this invention;
FIGURE 2 is a perspective view of the member shown in FIGURE 1 being employed in the structure of an automobile to provide support for bumpers;
FIGURE 3 is a longitudinal view of an unfinished tubular member used in the preferred embodiment of this invention;
FIGURE 4 is a longitudinal view of the tubular member of FIGURE 3 after a successive step in processing it into the preferred embodiment of this invention;
FIGURE 5 is a longitudinal view of the tubular member of FIGURE 4 after a further successive step in the processing of the member into a preferred embodiment of this invention;
FIGURE 6 is a cross-sectional view of the member shown in FIGURE 5;
FIGURE 7 is a partial sectional view of a portion of the member shown in FIGURE 1;
FIGURE 8 is a partial sectional view of the portion of the member shown in FIGURE 7;
FIGURE 9 is a perspective view of an alternate embodiment of this invention;
FIGURE 10 is a perspective view of still another embodiment of the invention; and
FIGURE 11 is a partial sectional view taken along line 11—11 of FIGURE 10.
Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application as to details of construction and arrangement of parts illustrated in the accompanying drawings since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.
As shown in the drawings:
In FIGURE 1 there is shown a cylindrical steel tubular member 10 used in the preferred embodiment of this invention. The tubular member 10 has a central axis 12 extending longitudinally through the length of the member. Smooth right circular cylindrical portions 14 and 16 are located near ends 18 and 20, respectively, of the member 10. In between portions 14 and 16 are a plurality of outwardly bulging accordian-like or barrel-like portions 22. Each of these barrel-like portions 22 is bordered by annularly depressed grooves 24 peripherally or circumferentially impressed on the tubular member 10. Intermediate each of these grooves 24 and coextensive with the radially outwardmost portion of the barrel-like portions 22 are annularly depressed grooves 25 circumferentially impressed on the tubular member 10.
Each of the barrel-like portions 22 comprises bracketlike elements 28 disposed between pairs of slits 26 and the grooves 24. The grooves 25 are located at L-shaped junctions of portions 30 and 32 of the bracket-like members 28. In the preferred embodiment of this invention the portions 30 and 32 are raised at angles of approximately 25 degrees with respect to the central axis 12 of the cylindrical tubular member 10.
The grooves 24 and 25 are made in the exterior sur