Railway rolling stock – Special car bodies – Shock absorbing
Reexamination Certificate
1998-12-29
2001-03-06
Morano, S. Joseph (Department: 3617)
Railway rolling stock
Special car bodies
Shock absorbing
C105S396000, C428S118000
Reexamination Certificate
active
06196135
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a shock absorbing underframe structure for railroad car use which relieves the shock of a collision.
2. Description of the Related Art
The conventional underframe of a railroad car is designed to relieve the stresses generated under various design loads such as vertical load, end-to-end compression load, torsional load, etc. within specification limits of strength so as to prevent plastic deformation. In addition, from rigidity considerations, the underframe is so designed that deformations under such loads will be within specified displacement values. This is a design concept with emphasis placed on strength and rigidity and constitutes a common practice in designing a railroad car frame structure inclusive of the underframe. It is a classical leading principle in the design of structures which is based on the password “acceptable if rugged”.
However, in view of the comparatively high incidence of collisions, the recent railroad car specifications, particularly the specifications for light-weight streetcars represented by the low-floor articulated car call for “collision-destructibleness” in lieu of the time-honored “non-destructible” structure. This concept was proposed because, in the conventional “non-destructible” construction, the degree of damage to the front end of the frame structure on the occasion of a collision is low but, instead, the car undergoes a sudden stop or rebounds with the front end more or less intact and hence imposes a remarkably great acceleration-deceleration load on the passengers aboard to inflict serious and even fatal damages. Since, in such a mere “rugged” construction, the front end structure is hardly destroyed by a collision, the amount of shock energy that can be absorbed as the plastics train energy of the structure is considerably small so that the shock can not be effectively attenuated.
Designed to obviate the above disadvantages of the prior art structure in association with a collision , the present invention has for its object to provide a shock absorbing underframe structure for railroad car use which is characterized in that the shock of a collision is attenuated for protection of passengers through an “easily destructible” structure locally built into the underframe.
For the reasons mentioned below, the underframe of a railroad car must be a “non-destructible” structure withstanding predetermined magnitudes of vertical load, end-to-end compression load, torsional load, and car-end lifting load. It is also necessary that the underframe structure be readily adapted to a variety of cars varying in shock resistance load.
SUMMARY OF THE INVENTION
The shock absorbing underframe structure of the present invention, therefore, is characterized in that at least two of the cross beams or end sill extending along the width direction of a car are disposed in parallel and spaced apart relation in the longitudinal direction of the car and, in addition, energy absorbing sills adapted to absorb shock energy by wall buckling when subjected to an impact force beyond a predetermined value from the front end of the car are disposed. The above-mentioned predetermined value for shock energy can be varied according to the number and arrangement of said energy absorbing sills.
The preferred shock absorbing underframe structure of the invention is characterized in that, in addition to the above basal structure, a reinforcing panel (preferably an aluminum honeycomb panel) is disposed on each side of the energy absorbing sill.
The more preferred shock absorbing underframe structure of the invention is characterized in that, in addition to whichever of the above structures, said energy absorbing sill is comprised of a member previously subjected to a local deformation for providing a trigger for wall buckling and a plurality of units of such energy absorbing sill are arranged in parallel (or serial and parallel) relation between said cross beams or end sills.
While the present invention is applicable to all kinds of cars inclusive of large-sized cars and high-speed cars, it finds application with more remarkable benefits in streetcars having a comparatively high risk for a collision and particularly in low-floor cars which are relatively more susceptible to damage on collision.
The shock absorbing underframe structure for railroad car use which includes energy absorbing sills disposed between cross beams according to the invention insures a large shock absorbing energy in the event of a collision.
Furthermore, when said reinforcing panel is disposed along the side of the energy absorbing sill, the length of the energy absorbing sill can be fairly increased with lateral buckling effectively prevented, with the result that a sufficient deformation stroke can be provided by the structurally simple contrivance.
Moreover, since the shock energy at colliding of the front end of the car can be remarkably decreased as compared with the conventional structure, the present invention contributes a great deal to the assurance of passenger safety without compromise in the capability to deal with the usual load conditions.
In addition, since various specifications can be easily satisfied by modifying the arrangement and number of energy absorbing sills in the longitudinal and transverse directions of a car, the invention can be applied to various types of railroad cars.
REFERENCES:
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patent: 4364482 (1982-12-01), Dilg
patent: 4715292 (1987-12-01), Pavlick et al.
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patent: 5601034 (1997-02-01), Tao et al.
patent: 5660116 (1997-08-01), Dannawi et al.
patent: 5895701 (1999-04-01), Givoni
Kashima Jun
Miura Yoshihiko
Okochi Shogo
Saito Tomohide
Ueta Kozo
Kinki Sharyo Co., Ltd.
Morano S. Joseph
Olson Lars A.
Vedder Price Kaufman & Kammholz
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