Railway rolling stock – Floors
Reexamination Certificate
2000-07-28
2001-11-27
Le, Mark T. (Department: 3617)
Railway rolling stock
Floors
Reexamination Certificate
active
06321661
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to modular construction of a floor for vehicles and, more particularly, to a metal floor structure attached to a railway car underframe for railway freight cars.
BACKGROUND OF THE INVENTION
Over the years, railway boxcars and freight cars have progressed from relatively simple general purpose wooden structures mounted on flat cars to more elaborate arrangements including insulated walls, refrigeration equipment, nailable metal floors, and other features for specific applications. Various types of railway boxcars and freight cars are presently manufactured and used. A typical railway freight car includes an enclosed structure mounted on a railway car underframe. The enclosed structure may include an outer shell and interior paneling. For some freight cars, such as refrigerated box cars, one or more layers of insulation may be disposed between the outer shell and the interior paneling.
The outer shell of a railway freight car often has an exterior surface formed from various types of metal such as steel or aluminum alloys. The interior paneling is often formed from wood and/or metal as desired for the specific application. Sliding doors are generally provided on each side of the enclosed structure for loading and unloading freight. Conventional railway freight cars may be assembled from various pieces of wood, steel and/or sheets of composite material such as fiberglass reinforced plastic and generally require significant amounts of raw material, labor and time to complete manufacture and assembly of each freight car.
The underframe for many railway freight cars includes a center sill with a pair of end sills and a pair of side sills arranged in a rectangular configuration corresponding approximately with the dimensions for the floor of the freight car. Cross bearers and cross ties are often provided to establish the desired rigidity and strength for transmission of vertical loads to the center sill. A plurality of longitudinal stringers are typically provided on each side of the center sill to support the floor of the enclosed structure. Examples of such railway car underframes are shown in U.S. Pat. Nos. 2,783,718 and 3,266,441. Both of these patents are incorporated by reference for all purposes within this application.
For many years various techniques have been used to provide nailable steel floors for railway freight cars. The Association of American Railroads (AAR) Mechanical Division Manual of Standards and Recommended Practices, Specification M-964-92 provides information concerning the manufacture and testing of such nailable steel floors. U.S. Pat. No. 4,224,880 entitled “Railway Car Nailable Floor” provides additional information concerning such floors. This patent is incorporated by reference for all purposes within this application.
Various types of load dividers and freight securing systems have previously been used to prevent undesired movement of freight contained within an enclosed structure of a railway freight car. The use of such systems is particularly important when the freight car is only partially loaded. Examples of such systems are shown in U.S. Pat. No. 5,370,482 entitled “Cargo Securement System” and U.S. Pat. No. 5,386,674 entitled “Two Piece Bulkhead Door for Rail Cars and the Like.” The above patents are incorporated by reference for all purposes within this application.
Nailable metal floors provide advantages over wooden floors. A typical nailable metal floor structure may include multiple floor panels. However, the floor panels are typically comprised of several nested metal planks. This results in complex construction of the floor panels and a series of grooves in each floor panel. Also, an additional metal strip must be applied across each end of the panel to “finish” the panel ends.
SUMMARY OF THE INVENTION
In accordance with the present invention, disadvantages and problems associated with previous modular floors for railway freight cars have been addressed. The present invention provides a nailess floor structure which may be assembled from floor panels to provide a smooth floor surface extending throughout the interior of the resulting railway freight car. The floor panels are preferably fabricated from appropriate metallic and/or nonmetallic materials in accordance with teachings of the present invention prior to assembly of the associated railway freight cars.
One aspect of the present invention includes providing metal floor panels which may be fabricated prior to installation within a railway freight car. For one application, the present invention provides a metal floor structure satisfactory for use in railway freight cars subject to lift truck axle loads of 60,000 pounds. For another application, the present invention provides a metal floor satisfactory for use in railway freight cars subject to lift truck axle loads of 80,000 pounds. In both applications, the resulting metal floor structures satisfactorily passed dishing, web crushing, and beam strength tests, as defined by AAR Specification M-964-92 for nailable steel floors.
Another aspect of the present invention includes providing floor panels with bent-down end portions for coupling the floor panels to a railway car underframe and for interfacing with side sills of the underframe.
Another aspect of the present invention includes providing floor panels which include one-piece floor plates connected to one or more reinforcing members. The floor plates of adjacent floor panels may abut each other and may both be connected to a common overlapping reinforcing member.
Technical advantages of the present invention include providing a floor structure with a smooth metal surface while minimizing the weight and, at the same time, maximizing the strength of the floor structure. Floor panels may be fabricated in accordance with the teachings of the present invention for attachment to a wide variety of railway car underframes such that the time required to install the resulting floor structure during assembly of the associated railway freight car is substantially reduced. The floor panels may be fabricated prior to assembly of the associated freight car to minimize the total number of parts that must be handled during assembly of the floor structure. Floor panels and floor plates incorporating teachings of the present invention allow relatively easy access to those locations which require welding of the resulting floor structure to the associated railway car underframe. Using standardized floor panels to form the floor structure in a large number of railway freight cars allows reducing both manufacturing costs and material costs associated with each floor panel and also reduces the amount of time, material and labor associated with installation of each floor structure in the associated railway freight car. A floor structure formed in accordance with the teachings of the present invention is particularly adapted for use in freight cars carrying products such as rolls of paper or automobile parts which are preferably shipped on a smooth floor surface.
Further technical advantages of the present invention include providing a number of floor panels having a generally rectangular configuration. Each floor panel preferably includes a floor plate with a plurality of reinforcing members attached to one side of the floor plate. One reinforcing member is preferably attached to and partially extends laterally from one edge of each floor plate such that the other edge of an adjacent floor plate may be welded to the portion of the reinforcing member. The ends of each floor plate are preferably bent downwardly for use in attaching the respective floor panel with portions of the railway car underframe. The combination of providing a butt weld between the adjacent edges of each floor plate and bending down the opposite ends of each floor plate results in a floor structure with no leaks between adjacent floor panels and around the perimeter of the resulting floor structure.
REFERENCES:
patent: 1828842 (1931-10-01), Loucks
patent: 2180504
Basile Fred M.
DiLuigi Michael W.
Womack Charles D.
Baker & Botts L.L.P.
Le Mark T.
TRN Business Trust
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