Railway rolling stock – Floors
Reexamination Certificate
1999-04-19
2001-01-30
Morano, S. Joseph (Department: 3617)
Railway rolling stock
Floors
C105S396000, C105S404000, C296S204000
Reexamination Certificate
active
06178895
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention has to do with a flat-surfaced floor structure for a railroad boxcar.
The floor structure of a boxcar must support the weight of the contents of the boxcar and is carried on an underframe that is, in turn, supported by two wheeled trucks. Additionally, the floor structure must support the weight of loading machinery, such as a loaded forklift that travels within the boxcar, without suffering significant permanent deformation. One boxcar floor structure design criterion that is generally recognized in the industry is the ability to withstand a lift truck axle load of 60,000 pounds without suffering permanent deformation. Furthermore, these goals should be achieved with a minimum weight, in order to allow a maximum load to be placed in the boxcar without exceeding the maximum weight limit for a loaded boxcar. The floor surface should also be as close to the top of rail as possible, to allow as much vertical clearance within the boxcar as possible, as the height of the boxcar roof is limited by clearance requirements. Cost of manufacture is also of concern in a boxcar floor design, because boxcars are sold in a competitive market.
In the past, most boxcar floor structures have been formed so as to allow nails to be driven into the floor at various places to secure loads. In the industry this is termed a “nailable floor.” Such floors are typically formed by placing abutting formed steel “planks” or channels, open side down, over the longitudinal stringers of the boxcar underframe so that nails can be inserted between and held by the abutting formed channels. Although this continues to be a useful configuration for the floor of a boxcar, there are some applications, such as hauling paper rolls or other goods having a relatively delicate exterior, for which a flat floor is preferred.
For a flat floor it is generally necessary to support a set of flat plates over the stringers. As the stringers are not typically arranged closely enough together to adequately support the plates, it is necessary to position closely spaced structural members transversely over the stringers. Heretofore, the members of choice for this function have been formed steel channels, installed with their webs, or side walls, vertical and their bases horizontal. The vertical webs, or side parts, of these channels are able to support a heavy load, whereas the horizontal, or base, portions can be attached to the stringers or provide reinforcement for the floor plates.
One floor structure that is currently available uses steel floor plates and formed channels that are both of material 3.797 mm (0.1495″) thick. The formed channels are 52.3875 mm (2-{fraction (1/16)}″) wide and are spaced 50.8 mm (2″) apart. This assembly is heavier than is desirable. Another floor structure also uses 3.416 mm (0.1345″) thick steel sheet both as the top sheet and for formed “hat”-shaped support members. In this assembly the formed hat-shaped members are spaced with a pitch of 152.4 mm (6″). Unfortunately, this arrangement suffers permanent deformation when a loaded 60,000-pound fork lift axle load travels over it. A floor structure that is not prone to permanent deformation from the weight of a loaded 60,000-pound lift truck axle load, but that is not substantially heavier than existing floor structures would be highly desirable.
One element of boxcar underframe design that has traditionally presented a challenge to design engineers is the accommodation of the wheels of the boxcar. In most designs, the pattern of structural elements that is present over most of the area of the boxcar floor would contact the wheels if it was extended into the wheel wells. In a prior construction, to avoid this occurrence, the pattern of structural members is interrupted, forming a well to accommodate each wheel. A heavy gauge steel plate defining a through-hole for accommodation of a wheel is attached to the underframe above each wheel, to provide the needed structural strength. Unfortunately, these heavy gauge plates must be specially made and add weight to the boxcar.
In one prior art nailable floor, each formed channel plank that bridges the wheel well is reinforced with a steel plate that closes the downwardly facing channel. The extra strength imbued to the floor structure by this addition permits the omission of the heavy gauge steel plates necessary in previous designs.
What is needed, then, is a floor structure that can withstand the weight of loaded 60,000-pound fork lift axle load without suffering permanent deformation, yet is lighter and can be more economically constructed than previously existing floor structures.
SUMMARY OF THE INVENTION
The present invention answers the aforementioned needs by providing a floor plate assembly for a railway freight car structure and a floor plate support assembly for use in such a floor plate assembly.
In one embodiment of the invention the floor plate support assembly includes a channel member having a base and at least one side wall having an outer margin. A reinforcing bar is welded to the base and has a margin parallel to and aligned with the margin of the side wall. A floor plate assembly which is one preferred embodiment of the present invention includes a plurality of such floor plate support assemblies arranged parallel with each other and fastened to a flat floor plate.
A separate aspect of the present invention provides a floor plate assembly adapted to be supported by the stringers of a railway boxcar structure and comprising a structural member having a base, a pair of side walls extending from the base and each side wall having an outer margin, with a flange extending outwardly from the outer margin of one of the pair of side walls, and a pair of adjacent floor plates, each adjacent floor plate being supported at least in part by the flange.
An additional separate aspect of the present invention is the provision of a railway car, comprising a pair of wheeled trucks, a body bolster supported by each truck, a pair of side sills supported by the body bolsters, a center sill supported in part by the body bolsters and a set of cross bearers spanning from the side sills to the center sill, supported by the side sills and supporting the center sill. A set of stringers are supported by the cross bearers and in turn support a set of floor plate support assemblies, each support assembly having a base, a pair of side walls and a reinforcing bar welded to the base between the side walls and extending substantially parallel to the side walls. Finally, a set of floor plates are welded to and supported by the floor plate support assemblies.
A further separate aspect of the present invention is a method of producing a boxcar floor structure including a floor plate, including the steps of providing an elongate structural member having a base and at least one side wall extending away from the base, welding a reinforcing bar to the structural member so that it extends longitudinally parallel to the side wall, and attaching a floor plate to the structural member.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 2575454 (1951-11-01), Kuhler
patent: 3026821 (1962-03-01), Oakley
patent: 3319393 (1967-05-01), Tantlinger et al.
patent: 4645258 (1987-02-01), Ohmura et al.
patent: 5549350 (1996-08-01), Akiyama et al.
patent: 5918549 (1999-07-01), Basile et al.
Becker Bruce D.
Saxton Gregory J.
Chernoff Vilhauer McClung & Stenzel LLP
Gunderson, Inc.
Jules Frantz F.
Morano S. Joseph
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