The present invention relates to a method of manufacturing concrete sleeper blocks of varying lengths intended for railroad switch-points wherein respective sleeper blocks have a mutually different number of rail attachment devices in mutually different positions Thereon, said rail attachment devices being mounted in raised surfaces, referred to as projections or promontories on the concrete sleeper block, said projections preferably having an inclined surface, wherein a number of matrices are placed in a long form bed and concrete is poured into the bed and allowed to cure and harden.
The sloping surfaces on the projections in the concrete sleeper blocks are intended to provide so-called inclined rail positions. Inclined rail positions are today a normal standard with conventional concrete sleeper blocks and are becoming increasingly normal in sleeper blocks intended for railroad switch-points.
The degree of inclination varies in accordance with prevailing standards applied with the railroad system concerned. In the USA, the inclined surface shall have a slope of 1:40. The permitted tolerance range is very small, allowing the slope to vary within the limits 1:42-1:38.
It will be realized that in order to maintain this accuracy standard, high demands are placed on those matrices used in the manufacture of sleeper blocks of which the aforesaid promontories on which the rails rest form an integral part of the block.
The present invention, however, also relates to the manufacture of sleeper blocks that are provided with projections which do not slope, i.e. with which the raised surface is used to adjust the height position of the rail, for instance.
Correspondingly, the invention also relates to a matrix and a matrix array for the manufacture of concrete sleeper blocks of the aforesaid kind intended for railroad switch-points.
SE,B, 7812505-1 (publication number 415 868) (A-Betong) describes a method of manufacturing concrete sleeper blocks of varying lengths intended for railroad switch-points and having a different number of positions for rail attachment devices. This known method involves the use of a number of thin matrices whose lengths correspond to the lengths of the different sleeper blocks and exhibit detachably mounted attachment devices which are placed end-to-end in a long form bed with the attachment devices facing upwards. A number of reinforcing lines or corresponding devices are tensioned in the form bed and concrete is poured into the bed and allowed to cure and harden. The cured, coherent concrete body is then removed from the concrete form and the matrices are removed from the concrete body and the attachment means moulded therein, whereafter the concrete body is cut into lengths corresponding to the desired lengths of the sleeper blocks.
The concrete body can be stripped from the form, by lifting the concrete body from the form bed and turning the concrete body prior to removal of the matrices.
The matrices used with this known method comprise a number of mutually separated flat plates whose widths correspond generally to the upper surface of the sleeper blocks and the lengths of which vary to correspond with the desired length of individual sleeper blocks. The matrix plates are provided at predetermined, varying positions with holes for detachably mounting the attachment devices to be moulded in the sleeper blocks.
This known method and this known matrix array, which cannot be applied for the manufacture of switch-point sleeper blocks which exhibit inclined rail positions, constitutes the standpoint of techniques from which the present invention departs. The problems carefully set forth in the aforesaid publication are thus also relevant in the case of the present invention.
In addition to the problems set forth in the prior published specification, the switch-point concrete sleeper blocks to which the present invention refers shall be provided with integrated projections which will enable rails to be mounted in an inclined and in a level position, and that in the former case very high accuracy demands are placed primarily on the degree to which these projections are inclined.
EP,A1,0 268 028 (Wayss & Freytag) describes an arrangement for fixating tubular structural parts in sleeper blocks intended for railroad switch-points. This arrangement includes a nipple which firmly anchors a pin to a rail attachment part on a form bottom. This publication is not concerned with the manufacture of concrete sleeper blocks with which inclined rail positions are achieved in railroad switch-points.
Accordingly, one object of the present invention is to provide a method which will enable automated manufacture of switch-point concrete sleeper blocks of the aforesaid kind for inclined rail positions in long form beds and with which the high accuracy requirements placed on the end product can be fulfilled.
Another object of the invention is to provide a method with which sleeper blocks can be manufactured to the aforesaid degree of accuracy while keeping matrix costs down to a relatively low level.
Another object of the invention is to provide a method which will enable manufacture of the sleeper blocks to be adapted with the degree of flexibility required by the fact that the lengths of the end products and the positions of the rail-supporting projections vary with individual sleeper blocks.
Another object of the invention is to provide a matrix for the manufacture of switch-point concrete sleeper blocks provided with integrated projections which despite their relatively low costs can be used for long periods of time in the automated, mass production of such concrete sleeper blocks.
These and other objects are fulfilled with a method of the aforesaid kind having the characteristic features set forth in the characterizing clause of Claim 1.
The matrix dishes may be made of a softer material than the matrices themselves, so that the dished recesses or hollows can be formed with the aid of a press tool, the defining sides of these recesses preferably being inclined to the main part of the matrix. The angle to which the recess walls are inclined shall correspond to the value of the inclined rail position in the railroad system concerned, with small tolerances.
The matrix dishes shall be positioned accurately relative to the matrices and fixed in said positions prior to securing said elements thereto. To this end, the matrix dishes may be provided with flanges which are secured to the matrices when the matrices are placed in a form bed.
The flanges are conveniently provided with guide holes which are fitted over corresponding guide pins in the matrices.
The matrix dishes can then be secured temporarily prior to being permanently secured to the matrices, for instance welded thereto.
When the matrices are made of a soft material, the matrices are conveniently reinforced with a reinforcing or stiffening plate on the outer sides thereof. This reinforcing or stiffening plate may also be welded to respective matrix dishes.
It will be evident from the aforegoing that many different matrices will be used in the manufacture of concrete switch-point sleeper blocks. This means that the configuration of the matrix dishes and their positions in the matrices will vary. The holes provided in the matrices determine the positions of the respective matrix dishes and particularly when manufacturing short sleeper blocks intended to be placed at the actual switch-point it is possible that the holes will border on one another or even merge with one another. In this case, the matrix dishes are made shorter and are also adapted to this circumstance in other respects.
The types of attachment devices used may have different forms and may consist, for instance, of bolts, dowels, pandrol attachment means, etc., depending on the railroad system for which the sleeper block is intended. In order to obtain the best function of the projections formed with the aid of the matrix dishes, the longitudinal extension of the holes will preferably define an angle of between 0 and about 10° to the longitudinal axis of the matrices, meaning that the rail attachment devices will preferably be placed centrally along the matrix dishes.
In certain cases, the matrix dishes may be manufactured from material other than steel, for instance extruded plastic material.
In many cases it is convenient to provide the sleeper blocks with a drainage channel, which is taken into account in conjunction with configuring the matrices and the matrix dishes prior to placing said matrices and said dishes in the form bed.
The angle at which the matrix dishes are inclined and the depths to which said dishes are dished can be varied to correspond to different types of railtrack systems. For instance, the lengths of the matrix dishes will preferably be longer in the case of more robust rails than would otherwise be the case.
As mentioned in the aforegoing, the matrix dishes are suitably secured to the upper sides of respective matrices when the matrices are positioned in the form bed. In some cases, however, the matrix dishes may be secured to the undersides of the matrices.
Other securing methods than welding are conceivable, for instance glueing.
The invention also relates to a matrix which is used in the aforedescribed method of manufacturing concrete sleeper blocks, said matrix being characterized mainly by the features set forth in Claim 6.
According to another aspect, the invention also relates to a matrix array for the manufacture of switch-point concrete sleeper blocks, the main features of the matrix array being set forth in Claim 9.
The invention will now be described in more detail with reference to exemplifying embodiments thereof and also with reference to the accompanying drawings.
The principle method of procedure in the manufacture of switch-point concrete sleeper blocks of varying lengths and exhibiting different numbers of rail attachment devices in different positions along the blocks has been described in the aforesaid Swedish published specification SE,B,7812505-1 (A-Betong) and US,A,4,290,991 and US,A,4,495,127 and also US,A,4,522,367 of later date, all in the name Thim.
The reader is referred to these publications for a more detailed description of the general method of manufacture, the construction of the form bed and the general configuration of the matrices. All that will be mentioned here is that the illustrated form bed used with the present invention has, in practice, a length which exceeds the values recited in these publications and may have a length of 150 m or longer for instance, and also that the number of matrices included in a matrix array of the kind concerned here may also exceed the values recited in said publications, and may comprise in number, for instance, between 200 and 250 matrices, depending on the railroad system concerned and the type of switch-point for which the concrete sleeper blocks are intended.
In addition to the teachings of these publications with regard to the manufacture of concrete sleeper blocks, according to the present inventive method the rail attachment devices cast in the blocks shall be located on projections, or raised members, preferably on projections that have a sloping surface and are intended to enable rails to be laid in inclined positions.
These projections may have a horizontal surface and shall be integrated in the sleeper blocks, and to this end those matrices 1 which are intended to be placed at the bottom of the form bed in which the sleeper blocks are cast are provided with elongated holes with rounded defining surfaces, as shown in Figure 3. Matrix dishes or trays 3 of the general kind illustrated in Figures 1 and 2 are mounted in these holes.
The matrices have mutually the same thickness and width but vary in length and the holes in respective matrices are positioned differently in respective matrices, among other things depending on where the sleeper block being manufactured shall be placed in the track region of the switch-point concerned.
The matrix dishes 3 have asymmetric dished or recessed portions 3a which are intended to form in the sleeper block projections or raised surfaces that have sloping surfaces.
The matrix dishes are made from a grade of steel which can be press-shaped and which will enable the matrix dishes to be manufactured by stretching or pressing operations, with the aid of suitably configured tools.
The matrix dishes 3 have circumferentially extending flanges 3b which are intended to bottom against the regions that lie adjacent the hole edges of the matrices when the matrix dishes are inserted into the holes.
The sleeper blocks, and not least their projections, must be manufactured extremely accurately, and consequently it is highly essential that the matrix dishes are positioned and fixed accurately in the holes before being secured to the matrices.
To this end, the dish flanges 3b are provided with guide holes 5 for coaction with pins (not shown) outstanding from the matrices, so as to enable the matrix dishes to be guided to correct positions when inserted into the holes. Prior to securing the matrix dishes, which is normally effected by welding the dishes to respective matrices, the dishes are conveniently fixed in their correct positions with the aid of clamping devices.
The matrix dishes are provided with holes 4 for receiving anchoring devices 12 (cf Figure 4) for attachment devices which function to hold the rails on the sleeper blocks. These anchoring devices 12 are embedded in the concrete sleeper blocks.
Since the matrix dishes 3 are made of a softer grade of steel than the matrices, as beforementioned, the dishes are provided with a central reinforcing or stiffening plate 3c.
Figure 4 illustrates a part of a form bed in which a matrix 1 onto which a matrix dish 3 has been welded is shown in a position in which it forms the bottom of the form bed. A plurality of similar matrices of varying lengths are placed adjacent one another in the manner described in the aforesaid earlier published specifications.
Figure 4 shows two parts of a matrix 1 which has been cut through the middle. It will be understood ,however, that although not shown a further two matrix dishes are inserted in this cut-away area.
The side walls of the form or mould cavity have been indicated in chain lines 7 and 8.
The matrix dishes inserted in the holes in the matrices 1 are welded to the matrices. Figure 4 illustrates one such seam weld. Alternative welding methods, for instance spot welding, are also conceivable in this regard. Alternatively, the matrix dishes may be glued to respective matrices.
Figure 5 illustrates a finished concrete element that has been manufactured in the form bed. The concrete element is referenced 10 and the raised surfaces or projections formed by the matrix dishes and exhibiting sloping upper surfaces are referenced 10a. Figure 5 also shows anchoring devices 12 for anchoring rail attachment devices.
The concrete element shown in Figure 5 has been cut into two parts for the sake of illustration, although it will be understood that two rail supporting projections 10a (not shown) are located in the region of the concrete element not shown in Figure 5.
Figure 6 is an end view of the sleeper block 10 shown in Figure 5 provided with a projection 10a and an anchoring device 12 embedded in the sleeper block, said anchoring device having an anchoring part 12a which extends within said block.
Figure 7 illustrates an embodiment of the invention in which a matrix 1 has two dish receiving holes located close together. The matrix dishes will therefore encroach upon each other's space and it is necessary to modify the mutually facing end parts of the dishes.
It will be understood that the illustrated matrices and matrix dishes and the manner in which they are mutually connected may be modified within the scope of the invention.
In the manufacture of a plurality of concrete sleeper blocks necessary for a railroad switch-point there is used a matrix array which includes a plurality of matrices 1 to which matrix dishes have been fitted and which have essentially the same width but varying lengths, and in which the positions of those holes in which the matrix dishes 3 are mounted may vary.
The number of matrices used in such a matrix array can vary within wide limits, depending on the track system concerned and the characteristics of the switch-point in question.
The angle at which the upper surface of the projections on The manufactured sleeper blocks is inclined may also vary. According to American practice, The degree of inclination is 1:40, whereas according to Swedish and Danish practice the degree of inclination will preferably be 1:30 and 1:20 respectively. Other values may apply in other countries.
As beforementioned, the invention can also be applied to provide sleeper blocks with projections or raised surfaces which have generally horizontal surfaces, i.e. which do not slope. In this case, the matrix dishes are adapted accordingly and may have a generally symmetrical configuration.
The invention can also be applied in those cases in which the matrices are placed in the form bed so as to coincide with a vertical plane, i.e. so that the projections on the matrix dishes project out from one side of respective matrices. This method of manufacturing sleeper blocks is normally applied in the United Kingdom, among other countries.