Kinetic energy absorbing element

Details Kinetic energy absorbing element Kinetic energy absorbing element

1999-08-20

2001-08-14

Copenheaver, Blaine (Department: 1772)

Stock material or miscellaneous articles

Hollow or container type article

Polymer or resin containing

C428S034100, C188S371000, C188S377000, C267S136000, C267S292000, C267S293000, C267S294000

Reexamination Certificate

active

06274211

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to an element for absorbing kinetic energy which works mechanically based on the principle of plastic deformation.
2. Prior Art
DE-OS 19 21 049 discloses a mechanically acting absorbing element which is formed of at least two telescoping hollow cylinders with overlapping diameters. The absorption of energy is achieved in that the hollow cylinders are plastically deformed outwardly and inwardly when pushed together. DE-OS 29 49 677 shows a possibility for application of an element of this kind as a shock dissipating element inside a central buffer coupling of a railborne vehicle. In the known absorbing element, in particular, the large length of structural component parts and the considerable manufacturing cost (exacting dimensional tolerances) are considered disadvantageous. Another disadvantage is the large weight of the known element resulting from the required use of steel for the hollow bodies for purposes of a usable working capacity.
Further, energy-converting systems which are used primarily in the bumper area of vehicles in order to prevent damage to the vehicle up to predetermined collision speeds of, e.g., 8 km/h are also known from the prior art. Systems of this kind contain reversible hydraulic dampers which are technically complicated with respect to manufacturing and servicing and are accordingly relatively expensive and have considerable weight, or plastically deformable, i.e., non-reversible, bodies, e.g., aluminum honeycomb, which are predictably very heavy in general.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a light, predictable and easily handled element which can be manufactured economically for absorbing kinetic energy in a particularly small space and which maintains a constant working behavior throughout its period of use.
This object is attained according to the invention by an element for absorbing kinetic energy operating mechanically according to the principle of plastic deformation, which consists of a plastic pipe section having interior surfaces at opposite ends thereof and which initially deforms elastically under an applied axial force. When a yield stress limit of the plastic pipe section is exceeded by the applied axial force, the plastic pipe section deforms or collapses with an approximately equal deforming force over a work stroke until adopting a physically deformed shape in which the interior surfaces at the opposite ends of the plastic pipe section contact each other.
Advantageous developments of the invention are indicated in the subclaims.
The absorbing element according to the invention can basically be used wherever extensive damage to valuable objects must be prevented in the event of rarely occurring overload. The absorbing element is suitable, for example, as an energy dissipator behind a vehicle coupling or behind a vehicle bumper.
The absorbing element according to the invention can be adapted in a simple manner to the requirements of the application in question through the variability of its structural component geometry: the height of the block-shaped section of the thick-walled plastic pipe is decisive for the length of the spring path, the radial expansion when acted upon by force and force break-in when the outer contour of the block-shaped section is inclined by 45° during upsetting. As thickness increases, the wall of the block-shaped section reduces the available spring deflection or spring path and increases the rise in force beyond the state of yield stress. Finally, the cross section of the thick-walled section is decisive for the height of the elastic rise in force.
The initial elasticity of the absorbing element results on the one hand in a favorable protection against deformation during small impacts in many types of application; on the other hand, it provides the possibility for clamping or bracing the block-shaped section with other structural component parts, so that minor contact impacts will not cause longitudinal play. After a work stroke in excess of the yield stress, there is a plastic deformation of the block-shaped section, which should then be replaced because, depending on the degree of deformation, the maximum possible energy absorption will no longer be available. Static and dynamic characteristic lines are approximately identical; only the fullness of the curve increases dynamically. No elaborate dynamic tests are required for checking previously calculated characteristics.


REFERENCES:
patent: 3784181 (1974-01-01), Nemed
patent: 5161655 (1992-11-01), Shimoda
patent: 5529327 (1996-06-01), Huang
patent: 19 12 049 (1970-10-01), None
patent: 29 49 677 A1 (1981-06-01), None
patent: 2 152 181 A (1985-07-01), None

Affiliated with

Also associated with

Rating

Kinetic energy absorbing element does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Kinetic energy absorbing element, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Kinetic energy absorbing element will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2504981