Freight accommodation on freight carrier – Load bearer accommodation – Cushioned accommodation
Reexamination Certificate
2000-09-11
2001-08-28
Gordon, Stephen T. (Department: 3612)
Freight accommodation on freight carrier
Load bearer accommodation
Cushioned accommodation
C410S087000, C410S047000, C410S048000, C410S120000
Reexamination Certificate
active
06280127
ABSTRACT:
FIELD OF THE INVENTION
Our present invention relates to a shock-absorber attachment for a cover region or bottom region of a metal container, especially a high-strength steel or cast metal (cast iron) container for the transportation of radioactive material, especially depleted nuclear reactor fuel elements.
More particularly, the invention relates to a shock absorber which can be fitted onto or over the cover region and/or the bottom region of such a container and will absorb impact and like shocks which would otherwise be transmitted to the container and could contribute to weakening or rupture thereof.
BACKGROUND OF THE INVENTION
High-strength metal containers, usually of a high-strength steel or cast iron with or without strengthening reinforcements, are utilized inter alia for the storage and transportation of radioactive materials, for example spent nuclear fuel elements. Such containers may be shipped in various vehicles or vessels, supported against movement in frames or otherwise, and must contain the nuclear material in a perfectly sealed manner such that accidental release of contained materials can be reliably avoided.
To protect the ends of the container, e.g. the cover end or bottom region opposite the cover end, it has been proposed to attach a shock-absorber unit to the respective end.
For this purpose, the shock-absorber units which have been provided heretofore are composed of metal and are themselves container-like members which can be filled with or can receive a nonmetallic filling material. They can have a recess for the container end to be fitted therein and can be attached to the respective container end by screws or bolts.
The earlier shock-absorber systems were formed with radial ribs extending over part of the container end received therein.
Wood structures were received in the shock-absorber unit and the shock responsive region was confined more or less to the region overlapped by the shock absorber. In the case of a horizontal orientation of the container and with certain types of impact for shock, such shock absorbers offered only limited deformation volume and thus were inadequate.
OBJECTS OF THE INVENTION
It is, therefore, the principal object of the present invention to provide a shock-absorber attachment for the purposes described which will afford a significantly greater shock-absorbing and deformation volume in the case of a horizontal orientation of the container than has been obtained with shock absorbers of the type described heretofore or the shock-absorber attachments hitherto used for the ends of the metal containers for the transport of radioactive materials.
Another object of the invention is to provide a shock-absorber attachment for such a container which is more effective for a greater number of situations than has hitherto been the case with respect to such shock absorbers.
Still another object of the invention is to provide a low-cost, high-efficiency shock absorber which has a greater deformation volume and an increased area over which shock can be distributed than with shock absorbers for containers heretofore.
SUMMARY OF THE INVENTION
These objects are attained, in accordance with the invention, in a shock-absorber attachment which can be fitted onto the cover region or bottom region of a high-strength steel or cast-iron container, especially for the transport of radioactive material like spent nuclear-fuel elements, in which the shock-absorber unit is formed beyond the respective container end with a stiff pyramidic structure commencing at the respective container end and narrowing inwardly therefrom and provided with a step-reduction in the wall thickness toward the free outer side and filled with a synthetic-resin foam.
More particularly, the shock-absorber attachment of the invention for a cover or bottom region of a metal container for the transport of radioactive materials can comprise:
a shock-absorber casing formed with a recess receiving a respective end of the container and provided with means for bolting the casing to the end;
a metal punch-through-preventing plate received in the casing and spaced from the end of the container;
an angle-section ring forming part of the casing and surrounding the end of the container around the recess, the ring being formed with radial ribs spaced apart around the ring and spanned between flanges thereof;
a stepped-pyramidal element extending in the casing outwardly from the ring and the end of the container toward a free side of the casing opposite that which receives the end of the container, the stepped-pyramidal element being composed of metal sheet and having wall thicknesses decreasing stepwise from the end of the container toward the free side; and
a synthetic resin foam in the casing filling interstices thereof and in contact with the stepped-pyramidal element.
With the shock absorber of the invention, the stepped-pyramidal element provides a significant increase in the shock-absorbing region, i.e. the region in which the shock energy or force is absorbed or converted to distortion or deformation. The stepped pyramid has been found to be especially effective for the case in which the container is horizontally oriented since in the horizontal case it provides a greater internal stiffness and a crumbling or creasing zone with reduced lag time by contrast with the vertical case. The use of a synthetic-resin foam as a damping material filling the shock absorber simplifies manufacture, since it can be foamed in place and provides a more uniform force distribution than is obtainable with other fillers and without a filler.
According to a feature of the invention, the shock-absorber casing is rotationally symmetrical for use with a cylindrical container. The stepped pyramid should surround a central opening or a hollow extending from the outer side or free side of this pyramid to a punch-through-preventing plate received in the casing. It has been found to be advantageous, moreover, to provide the metal foam as a polyurethane foam and to provide the foam externally of the stepped-pyramid element such that it has a higher hardness (stiffness) than the foam within the stepped-pyramid element.
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patent: 5861204 (1999-01-01), O'Sullivan
Jones Bill
Spilker Harry
Dubno Herbert
GNB Gesellschaft fur Nuklearbehalter mbH
Gordon Stephen T.
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