Railways: surface track – Roadbed – Street crossing
Reexamination Certificate
1998-12-11
2001-03-06
Le, Mark T. (Department: 3617)
Railways: surface track
Roadbed
Street crossing
Reexamination Certificate
active
06196470
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a level cover for tracks, wherein the space present between the two rails of a track is filled or bridged by slabs arranged in pairs which engage by at least one rim ledge in the fishing surfaces of the rails and are merely supported on the rails, bridging the distance between the rails self-supportingly, the two slabs of the slab pairs being assembled in hinge-like manner.
Level covers for rails are provided to allow road vehicles to drive over track regions. A particularly important field of use is in level railway crossings, i.e. intersections between roadways and railway lines. There, the mounting of the constructional elements forming the roadway in the track region is of great importance, since vehicles passing the crossing, particularly the rail vehicles, exert considerable static and dynamic loads on the traffic paths. In the region of a level crossing, the elastic properties of the track, which to a great extent are determined by the rail bedding, should possibly not at all or only slightly differ from the respective properties demanded of the track portions following upon such a crossing. This appears feasible if the properties of the rail bedding are not changed by constructional elements of the roadway that directly rest on the bedding elements.
Thus, with level rail covers, one has arrived at types of construction in which the space present between the two rails of a track is bridged by slabs which engage in the fishing surfaces of the rails and are merely supported on the rails, bridging the distance between the rails self-supportingly. In this respect there exist types of construction in which single slabs each are supported on the two rails of a track by their oppositely arranged rims, elastic sections being arranged between the rims of such a slab and the fishing surfaces of the rails. Insertion of such slabs does comprise certain difficulties and requires experienced workers, and, as a rule, it is necessary to insert two angular elastic sections at least on one rim side of these slabs to them on the fishing surfaces of the rail, one of these angular sections being placed at the rail base and the other one below the rail head. One way of enabling a simple insertion of slabs which are to bridge the space present between the two rails of a track in a level cover for tracks and are to be supported merely on the rails consists in the use of slab pairs whose two slabs are assembled in hinge-like manner, the hinge axis extending in the longitudinal direction of the track. In a known level cover of this type (DE-23 50 759-A2) the insertion of this slab pair between the two rails of a track can be effected in a relatively simple manner by folding up the slab pair, yet on account of the design used there of the hinge-like connection in the form of a hinge rod inserted between the two slabs of the slab pair, on which hinge rod the slabs simply abut, strong lateral forces which attempt to press the rails apart are exerted by the slabs on the rails, if heavier loads act on the slab pair, which doubtlessly is detrimental; there is also the risk that the stability limit will be overcome and the slabs will swing through downwardly until the hinge zone will come to lie on the sleepers of the track.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a level cover of the initially defined type, in which the disadvantages of known designs are avoided and detrimental static and dynamic influences on the track and its bedding will be eliminated to the greatest extent, and wherein also the installation and removal of the slabs to be provided between the two rails of a track can be effected in a simple manner.
The level cover according to the invention of the initially mentioned type is characterized in that the slabs of each slab pair rest on each other at their facing rims, and carrying portions and resting portions alternatingly following each other in meander-like fashion are provided at each slab along the rim facing the other slab, the carrying portions being formed by indentations originating from the slab upper side and extending as far as to the rim facing the other slab, upwardly directed indentations originating from the slab lower side being formed below the resting portions, which indentations are shaped complementary to the indentations of the carrying portions, and that the resting portions of the one slab rest on the carrying portions of the other slab, and the resting portions of the other slab rest on the carrying portions of the one slab. By this design, the aforementioned object can be met well in a structurally simple manner. The hinge-like assembled zones of the slabs of each slab pair may simply be put toghether with the slabs being folded up, whereupon the slabs may be inserted between the rails without any problems, with the slab pair being levelled, and even if heavy loads act on the slabs, such as, e.g., occur when heavy trucks roll over them, the slabs will not be pressed apart.
A preferred embodiment which is characterized in that at those surfaces, on which the slabs of one slab pair contact each other, projections and indentations shaped complementary to the projections are formed, the projections latchingly engaging in the indentations for a mutual latching of the slabs, has the advantage that the positive fit of the slabs of one slab pair will be ensured over very long periods of time even if unfavorable vibrations act on the slabs.
For as simple as possible an insertion procedure of the slabs between the rails with little expenditure of force, and for enabling a simple removal of the slabs it is advantageous if the carrying surfaces provided in the carrying portions, originating from the rim facing the other slab of the slab pair, at first rise steeply, starting from the slab lower side, and then flatten. There, it is furthermore suitable and also advantageous for ensuring a stable positive fit of the slabs in their installed state over extended periods of time if the carrying surfaces provided in the carrying portions have a crowned shape, which shape inhibits a mutual movement of these slabs in the direction of the slab plane in the levelled position of the slabs of the respective slab pair. Such a crowned shape may be formed on a slab by a surface portion originating from the rim facing the other slab of the slab pair, which surface portion extends away from the lower side of the slab, and a consecutive surface portion which extends towards the lower side of the slab. If with such a design of the slabs it is desired to provide for an additional latching, it is advantageous if the latter is designed such that downwardly extending projections are provided at the front rims of the resting portions, and indentations complementary to these projections are provided on the carrying surfaces of the carrying portions.
Particularly suitable for the course of the levelling procedure during the installation of the slabs and for attaining as stable a position as possible of the two slabs of a slab pair relative to each other in the installed state is an embodiment which is characterized in that the crowned carrying surfaces are shaped like a toothing which allows for a sliding movement or rolling movement of the facing carrying surfaces and resting surfaces one on the other, up to a levelled position of the slabs of the respective slab pair, and which in the levelled position of these slabs locks against a movement of these slabs relative to each other.
Furthermore, there results a geometry favourable for the assembly of the slabs of a slab pair and for the subsequent relative movement of these two slabs during the installation procedure of the slabs, if it is provided for the slabs to be rounded at their facing rims from the plate lower side upwards, the radius of curvature being dimensioned equally to or smaller than the distance between these rims and the rail-side rims of the slabs. For as simple an assembly as possible of the slabs of a slab pair it is advantageous if it is p
Gmundner Fertigteile Gesellschaft m.b.H. & Co. KG
Le Mark T.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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