Brakes – Plastic deformation or breakage of retarder element – Crushable element
Reexamination Certificate
1999-09-28
2001-12-11
Butler, Douglas C. (Department: 3613)
Brakes
Plastic deformation or breakage of retarder element
Crushable element
C267S139000
Reexamination Certificate
active
06328145
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a structure for damping impact by mechanical deformation, the said structure being of elongate shape in an impact direction and of substantially constant running cross section.
By running section is meant the section over the essential part of the length of the structure for damping impact.
The invention applies in particular to railway vehicles.
The specifications of vehicles carrying passengers, and especially railway vehicles, require the presence of such structures for damping impact which are capable, by virtue of planned mechanical deformation, of absorbing the energy in the event of an accident to save human lives and safeguard equipment.
The energy absorption capacity requirements for such structures are higher and higher at a time when simultaneous efforts are being made to reduce the weights of the vehicles.
Such structures for damping impact must therefore be light and resistant to static forces. Furthermore, in the event of an impact, they must deform by being crushed in the manner of a “concertina”, essentially in the impact direction without transverse displacement or corkscrewing.
Document EP-B-621,416 describes such a structure for damping impact which is formed by longitudinal metal plates, welded together. The running cross section of the structure, which is constant in the impact direction, comprises a rectangle whose angles are connected by diagonals which form an X within the rectangle.
In the event of impact, deformation will begin randomly at either of the two longitudinal ends of the structure, which may result in unstable deformation and hence relatively low energy absorption.
Furthermore, it is established that, in the event of an impact, the longitudinal force borne in the impact direction by such a structure first reaches a peak threshold value above which crushing begins, then the longitudinal force declines sharply as a result of which the energy absorbed by the damping structure, equal to the area of the force/deformation curve, is relatively low.
It is therefore desirable to be able to limit the reduction in the longitudinal force borne by the impact damping structure in the course of its deformation.
However, this longitudinal force, corresponding to the acceleration experienced by the passengers in the vehicle, must not be too high for passenger safety.
Finally, it is established that the deformation of such a structure is limited by the accumulation of material taking place at the center of the X of the cross section during the crushing of the structure. Hence, the energy absorption capacity of such a structure is again limited.
SUMMARY OF THE INVENTION
The object of the invention is to solve these problems by providing a structure for damping impact whose deformation in the impact direction is better controlled, having greater stability during crushing, an increased deformation capacity in the impact direction and increased energy absorption capacity, and a relatively low weight, and causing accelerations which are tolerable for the passengers in a vehicle on which the structure is installed.
To this end, the invention relates to a structure for damping impact by mechanical deformation, the said structure being of elongate shape in an impact direction and of substantially constant running cross section, characterized in that the structure comprises longitudinal plates forming a central chamber and two lateral chambers disposed on either side of the central chamber, in that the said lateral chambers each have a continuous exterior transverse contour and in that the central chamber comprises at least one pair of oblique longitudinal plates which are inclined oppositely relative to a plane of symmetry of the structure parallel to the impact direction.
According to particular embodiments, the structure for damping impact may comprise one or more of the following features, taken individually or in any technically possible combination thereof:
the plates of the said pair of oblique longitudinal plates are connected longitudinally along a common edge parallel to the impact direction, and these oblique plates are connected longitudinally to the rest of the structure upstream of the said common edge;
the structure comprises a plurality of pairs of oblique longitudinal plates, the oblique plates of each pair being inclined oppositely relative to the said plane of symmetry of the structure, and the said oblique plates define, at least partially, dihedra disposed side by side;
the said oblique longitudinal plates are connected in pairs along respective edges each common to two directly adjacent oblique plates and, for each common edge, the two corresponding oblique plates are connected longitudinally to the rest of the structure upstream of the said common edge;
at least some directly adjacent oblique plates partially define a dihedron and are connected longitudinally upstream of the edge of the said dihedron by a longitudinal plate which extends orthogonally to the said plane of symmetry of the structure;
the central chamber comprises at least one longitudinal plate which extends substantially orthogonally to the said plane of symmetry of the structure, connecting directly adjacent oblique plates;
the central chamber has a substantially continuous exterior transverse contour;
the structure comprises transverse reinforcing members which are regularly spaced along the structure within at least one chamber, especially a lateral chamber, and which are solidly fixed to the longitudinal plates of the said chamber;
at least one longitudinal plate is equipped with means for increasing the longitudinal rigidity of the structure along the structure from a first longitudinal end of the structure forming a commencement end for its deformation; and
the said means for increasing the longitudinal rigidity of the structure comprise spaced apertures which are areas decreasing from the commencement end of the deformation of the structure.
REFERENCES:
patent: 4029350 (1977-06-01), Goupy et al.
patent: 4221413 (1980-09-01), Bonnestain
patent: 4227593 (1980-10-01), Bricmont et al.
patent: 4352484 (1982-10-01), Gertz et al.
patent: 4711481 (1987-12-01), Krage et al.
patent: 5461144 (1995-10-01), Guardiola et al.
patent: 5715757 (1995-10-01), Dannawi et al.
patent: 0 637 538 (1995-02-01), None
patent: 0655 565 (1995-05-01), None
patent: 2 698 932 (1994-06-01), None
patent: 2 708 691 (1995-02-01), None
patent: 2063973 (1981-06-01), None
Metzger Albert
Villemin Marc
Alstom Holdings
Butler Douglas C.
Kramer Devon
Young & Thompson
LandOfFree
Impact damping structure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Impact damping structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Impact damping structure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2575856