A CONCRETE SLEEPER BLOCK COMPRISING A RAIL SUPPORT INSERT PLATE OF ELASTOMERIC MATERIAL,A METHOD OF MANUFACTURE THE SLEEPER BLOCK AND A RAIL INSERT PLATE FOR CARRYING OUT THE METHOD

Abstract: A concrete sleeper block (2) has a rail support insert plate (1) of elastomeric material mounted i a recessed upper portion (2a) thereof. The insert plate has downwardly extending projections (1c) which are provided with holes and which are arranged to be accommodated in corresponding holes (2c) in the recessed portion (2a) of the sleeper block (2). The projections accommodate a securing means, for example in the form of a ball (1e) made of an elastic material, which when the plate is mounted are pressed down to a bottom position in the projection while expanding said projection in respective holes. A method of manufacturing the sleeper block and a rail support insert plate (1) of the kind described are also objects for protection.

Description: A concrete sleeper block comprising a rail support insert plate of elastomeric material, a method of manufacture the sleeper block and a rail insert plate for carrying out the method Technical Field The present invention refers to concrete sleeper blocks comprising one or more rail support insert plates of elastomeric material. The invention also refers to methods of manufacturing such concrete sleeper blocks by casting in a mould and to elastomeric rail support insert plates to be used thereby. Background art Described in Swedish Patent Specification No. 73 06727-4 (Publication No. 372 787) is a concrete sleeper block to which a rail support insert made of an elastomeric material is fitted. A high degree of accuracy is required when casting such concrete sleeper blocks, particularly with respect to the positioning of the insert plate in the form or mould prior to the casting operation. The plate must thus be arranged in an exact position in the form. However, even though it is placed exactly in position, there is a risk that the insert will bend or be tilted during a casting operation, thereby jeopardizing the desired final result. The cleaning and preparation of a form for a further casting operation must also be done thoroughly and exactly, since any concrete residues in the form may cause the insert plate to be misaligned, resulting in the aforementioned consequences, whereat it is necessary as a rule to scrap the whole of the cast sleeper block. For reasons of a functional nature, high demands are placed on the accuracy of the positioning of the insert plate on the sleeper block - in practice the permitted tolerance is atmost a deviation from the ideal measurement of 0.5 mm - and it will be under¬ stood that these demands are hard to meet, and that a large increase in personnel is required in each case to clean the form and to prepare it for a further casting operation, which results in a substantial increase in the cost of the final product. In addition hereto is the disadvantage of not being able readily to change an insert plate which has been cast in a concrete sleeper block, and hence if it is necessary to replace an insert plate for some reason or other, for example due to a worn plate, higher train speeds requiring another composition of plate material, or like reasons, the whole of the sleeper block must be scrapped and replaced v/ith a nev; sleeper block provided with an insert plate which fulfils prevailing requirements. The German Published Specification No. 1 139 104 describes a concrete sleeper block having a rubber insert plate which, according to one embodiment, is provided with a plurality of downwardly extending conical pegs which fit into correspondingly formed holes in the sleeper block. The disadvantage v/ith this arrangement, however, is that the insert plate is not fixed to the block reliably enough. Thus, there is a serious risk of the insert plate loosening from the block during the handling thereof, until said block is provided with a firmly fitting rail . Objects of invention One object of the present invention is to provide a sleeper block of the kind aforementioned in which an insert plate is fitted more readily while retaining the high degree of accuracy required with regard to final measurements; and which, when necessary, enables the insert plate to be changed without losing said accuracy and without requiring the whole of the sleeper block to be scrapped. A further object of the invention is to provide a sleeper block in which the insert plate is fixed more positively, thereby avoiding the aforementioned serious disadvantage. Brief summary of invention A concrete sleeper block according to the invention has a recessed upper surface portion which is adapted to receive the insert plate, said recessed portion having a plurality of downwardly extending holes in which a corresponding number of hole-provided pro¬ jections raging from the underside of said plate are received, each said projection carrying a securing means located in a downwardly pressed position. A sleeper block according to the invention avoids the above-mentioned drawbacks by the fact that the rail support insert plate is not cast into the sleeper block but secured on its upper surface in a reliable manner v/hich, however, make it possible to replace the insert plate v/ith a new one if need therefor should arise. A sleeper block according to the invention affords, further, the advantage that mounting of the insert can be readily automized. All the manual operations previously necessary when cleaning a form and preparing it for a further casting operation, and which need be carried out when the insert plate is cast into a sleeper block, are, thus, eliminated. A further important advantage is that the capacity of the form and the extent to which it is used can be increased, since less time is wasted on the non-productive work of cleaning and preparing the form. A further important advantage afforded by the invention is that while using the same equipment a plurality of sleeper blocks can be provided with insert plates simultaneously, v/hich is of particular value in those cases where a plurality of sleeper blocks are cast consecutively so as to form a continuous block in a long form bed, said continuous block being later cut into separate sleeper blocks, which are transported to a receiving station. Automatic mounting of the rail insert plates can therewith be carried out, for example, at a station located at the end of the manufacturing line, therewith enabling a plurality of sleeper blocks advanced one after the other to be provided simultaneously with rail insert plates, without requiring any appreciable manual v/ork. Subsequent to the insert plates being mounted in position, the sleeper blocks are ready for delivery, and can be loaded onto suitable transport vehicles. In accordance v/ith one advantageous embodiment, the securing means comprise the same material as the corresponding projections and are held in the upper part of a respective projection through the elasticity of the material or by means of a thin wall of material which breaks when the securing means are pressed dov/n. The advantage afforded hereby is that no additional work is required in mounting the actual securing means, v/hich is thus present in the insert plate from the beginning and v/hich is preferably formed and mounted in a "position of readiness" during the manufacture of the insert plate, said plate suitably being produced by casting or extrusion moulding processes. Alternatively, however, the securing means may comprise a material which is harder than that of the insert plate and can be delivered from the device or machine which mounts the insert plate on the sleeper block. In both of these principal embodiments of the invention the securing means may have the form of a ball, which in the first mentioned case thus comprises the same material as the projection and is suitably produced in conjunction with the manufacture of the insert plate. In " the second case, as before entioned, the ball may be loose relative to the plate and comprise a harder material, e.g. metal or a plastics material. In accordance v/ith a further embodiment of the invention, the securing means may have the form of a rod cr bar arranged to be pressed into the hole in a respective recess. In this case, a plurality of sequentially arranged rods or bars are suitably carried by the machine or device v/ith which the insert plate is mounted onto the sleeper block. To further secure the plate to the sleeper block, the recess and/or the plate may be coated v/ith means for binding the plate to the block. Ever- though the insert plate should be bonded or glued to the sleeper block in this manner - which undoubtedly greatly reduces the risk of the plate being unintentionally shaken loose - it is still comparatively simple to remove the plate, by bending the same away, should it be necessary to replace the plate for some reason or other. The invention also relates to a method of manuf cturing a concrete block of the above-mentioned kind and to an elastomeric rail support insert plate for carrying out the method. Distinguishing features of said method and insert plate, respectively, are given in the claims. Some embodiments of the invention will now be described in more detail with reference to the accompanying schematic drawings. Brief description of the Drawings Figure 1 is a perspective view of an insert plate for use in the method according to the invention. Figure 2 is a partially cut-away perspective view of the insert plate shown in Figure 1, in an upside down position. Figure 3 is a view of part of a machine v/hich provides simultaneously each of four sequentially arriving concrete sleeper blocks with two rail insert plates at a manufacturing station. Figures 4 and 5 are partial sectional viev/s illustrating different stages in the pressing of an insert plate into a concrete sleeper block and securing said plate to said block. Figure 6 is a sectional view or part of a modified insert plate provided with a securing means of a different form. Figure 7 is a corresponding sectional view of part of a further modified insert plate arranged to receive a different kind of securing means. Figure 8 is a sectional view of a projection of an insert plate, and illustrates a conceivable configuration of a hole formed in the projection. Description of preferred embodiments Referring to Figures 1 and 2, the reference 1 identifies a rail insert plate of elastomeric material, such as a plastics material or rubber, intended to be mounted to a concrete sleeper block of the kind shown in Figure 3. The insert plate has two mutually opposite, parallel side edges la arranged for accurate abutment with mutually opposing, substantially vertical surfaces 2c v/hich are formed in the sleeper block 2 and which define a recess in the upper surface of said block, said recess being arranged to accommodate the insert plate. Alternatively, however, the side block may have a flat upper side. The insert plate is provided on the underside thereof with four conical, tubular projections lc, each of v/hich ■ has a through-passing hole If and exhibits three longitudinally extending slots Id. Arranged in each of the projections is a securing means in the form of a ball le, v/hich is made of the same material as the insert plate and which is suitably formed in conjunction with the manufacture thereof. Thus, the ball le can be fixed v/ithin the projection by means of one or more thin walls If arranged to rupture v/hen respective balls le are pressed downwardly into a respective projection, for securing the insert plate to the sleeper block. Figure 3 illustrates part of a manufacturing station, suitably located at the end of a sleeper block manufacturing line, where, for example, four sleeper blocks 2 arranged in line are each provided simultaneously with two insert plates 1. In the vicinity of the recesses 2a of a sleeper block there are arranged four holes 2b formed v/hen casting the block by placing bolts or like elements in the form. The holes 2b are located so as to receive the four slotted projections lc of an insert plate. For the purpose of mounting, for example, eight insert plates simultaneously there are used four mounting units 5 arranged in line, each of said units being provided at both ends v/ith a hydraulic or pneumatic plate mounting device 6. Each device 6 holds a plate 1 in the manner illustrated in Figure 3 and, v/hen respective sleeper blocks occupy their correct positions, move the plate down tov/ards the sleeper block, so that the dov/πwardly extending projections lc of the plate 1 enter the holes 2b in the region of respective recesses 2a. The continued mounting sequence is illustrated in Figures 4 and 5, which show how the mounting device works. Each device 6 has an associated press plate 7 provided with abutment means 7a which engage the side edges la of respective plates and which contribute, to a certain extent, towards pressing the plate down against the sleeper block in a manner such that the projections lc partially enter the holes 2b. As illustrated in Figure 4, the downwardly extending pegs 7b projecting from the plate 7 come into abutment with the bail le located in respective projections lc. Further downward movement of the press plate 7 causes the pegs 7b to release respective balls le from the thin walls v/hich hold the ball in the projection, as a result of the pressure exerted on the plate 7, whereat the balls le are pressed down into respective projections lc as the press plates continued to move downwards, whereat the parts of the projection lc defined by the slots Id are pressed outwardly into precise abutment v/ith the walls of the holes 2b. In the end position illustrated in Figure 5 the plate has been accurately pressed into the recess 2a in the sleeper block and is secured thereto by means of the balls le which urge said parts of the projections lc against the surrounding wall of the holes. The plate mounting devices illustrated in Figures 3-5 can operate substantially fully automatically. The finished sleeper blocks are then transported to a receiving station. Figure 6 is a sectional view of a part of a modified insert plate provided with cylindrical projections and holes which are conical in only the upper part thereof, i.e. the major part of the projection is tubular. The Figure illustrates a securing means in the form of a ball 10 which is separate from the plate and v/hich is • made of a harder material than said plate, for example of metal or a plastics material. These balls are carried in the machine which mounts the plates and are pressed down into the securing position by means of pegs of the kind referenced 7b in Figures 4 and- 5. Figure 7 illustrates a further modification. Thus, the part of an insert plate illustrated in this figure has a cylindrical projection v/ith a conical through-passing hole. In this embodiment, the securing means comprises a rod 11 which is joined with an overlying rod by means of a fractural impression. Such rods can thus be carried in the mounting machine in coherent rows and are separated from each other prior to or after the down- pressing operation. The holes If formed in the projections lc of respective plates need not be circular, as illustrated in Figure 8 which is a sectional view through one such projection lc having a Y-shaped or star-shaped hole If. As will be understood, the shape of the securing means corresponds to the shape of the hole. The sleeper blocks are normally provided with rail fittings (not shown) cast into the blocks in the region of said insert plates.

Claims: Claims 1. A concrete sleeper block comprising a rail support insert plate of elastomeric material, characterized in that the sleeper block has a recessed upper surface portion (2a) adapted to receive the insert plate (1) , said recessed portion having a plurality of dov/nv/ardly extending holes (2b) in which a corresponding number of hole-provided projections (lc) raging from the under¬ side of said plate are received, each said projection carrying a securing means (le; 10; 11) located in a downwardly pressed position. 2. A concrete sleeper block according to claim 1, characterized in that the securing means (le) are made of the same material as corresponding projections (lc) and are held in the upper part of the respective projection by the elasticity of the material or by a thin v/all of material which is arranged to break when the securing means is pressed downwardly. 3. A concrete sleeper block according to claim 1, characterized in that the securing means (10; 11) are made of a harder material than the plate and are delivered from a machine which mounts the plate (1) onto the sleeper block (2) . - 4. A method of manufacturing a concrete sleeper block comprising a rail insert plate of elastomeric material, characterized by casting the sleeper block (2) in a mould and providing its upper surface with a recessed portion (2a) having a plurality of holes (2b) , mounting onto the hardened sleeper block a plate (1) of elasto- " meric material having a plurality of projections entering said holes by pressing the plate into accurate abutment with the said recessed portion (2a) and securing the plate to the sleeper block with the aid of securing means (le; 10; 11) positioned in holes (If) in said projections (lc) by pressing the securing means into bottom portions of said holes (If) . 5. A rail insert plate comprising an elastomeric material and being intended for a concrete sleeper block, characterized by a plurality, suitably four,- hole-provided projections (lc) which project downward- ly from the underside of the plate (1) and v/hich carry or are intended to carry a securing means (le; 10; 11) arranged to be pressed down into the projection for securing the plate to the sleeper block. 6. A rail insert plate according to claim 5, characterized in that the securing means (le) is made of the same material, as a corresponding projection (lc) and is initially held in the upper part of the projection by the elasticity of said material or a thin v/all of material arranged to break when the securing means is pressed down into the hole of said projection. 7. A rail insert plate according to claim 5, characterized in that the projections (lc) and/or the holes (If) therein are of conical configuration. 8. A rail insert plate according to claim 5, "characterized in that the projections (lc) are provided with slots (Id) . .

Inventors: ROSVALL A, WESTBERG S
Applicants: A BETONG AB, ROSVALL A, SABEMA MATERIAL AB, WESTBERG S
Application year: 1981
Main classification: E01B9
IPC codes: E01B9, E01B29