AU2008252869B2 - Bolting system for points changing in railways - Google Patents

Abstract

The invention comprises two bolt bodies (1, 2, 32, 33) linked by an intermediate bar (5, 37) and with one of them connected to an external actuating mechanism, arranged transversely to the railway and suspended from the respective shoe (6, 35) of the counterpoint (4, 36). The needles (3, 34) are moved by means of respective sliders (14, 43) which slide within a box (9, 39) fastened to the bolt bodies (1, 2, 32, 33). Bars (15, 38) slide in each of the sliders (14, 43) and the bars are lockable (15, 38) with the sliders (14, 43) and the sliders (14, 43) with the boxes (9, 39). The bar (38) has two wide rabbets (48, 49) each for housing a roller (50, 51) which move in each of the transversal sheaves (52, 53) of the slider (43). These rollers (50, 51) interact with the semicylindrical rabbets (54, 55) of the box (39). The relative position of the rollers (50, 51) controls whether the slider (43) is dragged or not.

Description

-2 BOLTING SYSTEM FOR POINTS CHANGING IN RAILWAYS TECHNICAL FIELD The present invention relates to a bolting system for points changing in railways which presents in at least some of the disclosed embodiments stability and security of functioning, along with ease of fitting and removal, moreover requiring minimum maintenance. In some embodiments, this invention is also applicable to movable point frogs. In at least some embodiment disclosed is a greater smoothness in functioning, along with optimum precision in the closed and open positions of the point, and to prevent oscillations of the point produced when trains pass over it. BACKGROUND OF THE INVENTION Railway traffic needs rails which are displaced (movable rails or points) so that trains can pass from one track to another, along with movable points which move from one position to another in synchrony with the switches. Owing to the requirements of these movable rails, railway junctions are among the most dangerous sections of track, where the risk of derailment is high. In order to minimize these risks, the movable rails (points) have to be perfectly fixed in their final positions, without being affected by vibrations and blows produced by the passage of the trains. The bolts traditionally used are cheap, they have the problem of requiring frequent maintenance, and they perform badly. Previous patent applications involving an improvement in this system was developed in patents E00941990, E02028920 or E91041200, in which the elements that are used in the maneuver roll rather than slide, which minimizes stresses, as well as not requiring periodical greasing. Nevertheless, by applying an exterior force on the point of union of the two rails, one can manage to separate them and the point is only locked in the closed position. Moreover, their tightening is affected by changes in gauge. Another improvement can be found in the US patent with a publication number US005730395A, which discloses a locking apparatus for locking a point of a rail switch comprising two independent bolt bodies linked by an intermediate bar of adjustable length and arranged transversely to the line.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. SUMMARY In general terms, the present invention is directed towards bolting system for points changing in railways and in movable point frogs achieving a synchronous movement of the two points, and also, once positioned and the force pushing them has disappeared, they may remain in that position without being affected by vibrations and blows produced by the passage of the trains. In a first aspect, a bolting system for points changing in railways is disclosed comprising two independent bolt bodies, one for each point or movable rail, linked by an intermediate bar of adjustable length and arranged transversely to the line, said bolt bodies being simultaneously displaced by a device having mechanical or hydraulic actuation, each bolt body being suspended from the shoe of the counterpoint or fixed rail and formed by a box provided with means of fastening to the shoe of the counterpoint; there existing a slider which slides within the box and which at its end bears a support integral with it to which is secured the point; provision having been made for the displacement of the sliders and therefore that of the points to be effected by means of separate bars which axially traverses the sliders and with which they are able to be axially locked; each slider adopting two fixed positions with respect to the respective box, corresponding to the ends of travel of the angular movement of the point; the respective bars of each bolt body are joined together by said intermediate bar of adjustable length and one of them is in turn joined to the actuating device; each bar includes two rabbets wherein separate horizontal rollers which move in respective transversal sheaves of the slider can be partially housed, being able to move freely within the box in this position; the supports linked to the sliders and which press the respective points against the counterpoints in the closed condition, do so via some plate springs which push on a yoke and this on a tightening roller against an appendage integral with the point; the support linked to each slider is a freely rotating piece with respect to the latter, due to including an annular piece coaxial with a radial arm which defines the thrusting piece bearing the plate spring, the tightening roller being fitted horizontally in the yoke and being able to be displaced vertically by rolling -4 on a vertical plaque of the appendage; wherein the appendage integral with the respective point includes a lower extension with a horizontal roller which is able to be housed beneath a projection of the box eliminating the vertical oscillation of the point in the closed position. In some forms, the support joining the slider to the point has an insertion hole for the slider and integral with the latter is an appendage secured by means of a screw to the shoe of the point and the appendage being connected in articulated fashion to said support by means of a pulley-wheel fixed to a vertical pin. In some forms, the support inserted in the slider has a small axial displacement assisted by springs which push it towards the buffer close to the fixed rail or counterpoint in order to keep the point in contact with the counterpoint and said springs being supported in a tightening unit fixed in the end zone of the slider. In some forms, the box is provided with two semi-cylindrical rabbets at a greater distance between each other than those of the bar in which they can be partially and respectively housed, fixing the closing and opening positions of the corresponding point, the closing position being determined in the withdrawn condition of the bar due to the closing roller being advanced with respect to the rear wide rabbet of the bar and within the rear semi-cylindrical rabbet of the box; the opening position being determined as the bar initially advances and the closing roller housed in the rear cylindrical rabbet of the box falls into its rear rabbet, and the opening roller continuing in its wide rabbet of the bar without reaching the forward semi-cylindrical rabbet of the box, until, having reached the latter, it is forced to overcome the rabbet of the bar and be housed in the forward semi-cylindrical rabbet of the box, continuing thus until completing the opening travel of the bar where the point reaches the locking in its maximum separation from the counterpoint. In some forms, the tightening of the point against the counterpoint is adjustable due to the yoke being threaded in the spring-holder. In some forms, the wide rabbets of each bar are widened or of larger size than those of the box in order to freely permit the descent of the closing roller as the bar advances until the same roller guided by the slider exceeds the rear semi-cylindrical rabbet of the box; and the opening roller is more easily raised -5 due to reaching the forward semi-cylindrical rabbet of the box as the advance of the bar continues. In order to achieve a minimum or zero maintenance, the mechanisms may be sealed to prevent the entry of dust and water. The movable pieces have to slide on anti-friction materials, (Teflon, molybdenum, bronze, etc.) and, where possible, they have to roll. As the intervals for carrying out maintenance on tracks are becoming increasingly less, easy fitting and removal has to be achieved, so that, if a failure occurs in the bolt, it can be quickly replaced by a spare so that the track is left in a condition for being used. The broken piece is removed and repaired. Achieving easy fitting and removal may be possible if the mechanism is a single body which is extracted by releasing a few pieces in a reasonably short space of time. The system may be used in a hollow sleeper, or close to one of them and consists of two independent bolt bodies, one for each point, but joined by an intermediate bar adjustable in length. Being independent, they may be easily removed. Moreover, they are not affected by variations in gauge that may take place, nor do they need any precision in the alignment and leveling between the two bodies. Each body may be suspended from the shoe of the counterpoint (fixed rail), by means of a fastening achieved with clamps, which avoids the need to drill the rail in order to be able to fix a bolt. In some forms, attached to the point (movable rail) is an appendage which is fixed to the shoe thereof with a single drill-hole. The expansion due to temperature changes of the point produces the displacement of the point with respect to the appendage, but the bolt permits this since provision has already been made for the bolt-point union to be carried out by means of a rotating pulley-wheel via which the pushing and pulling of the point takes place. Described below is the kinematic chain of functioning. The piece which produces the locking of the mechanism is a roller which moves between two fixed positions where it remains recessed and as it moves it mechanically joins two different pieces: slider and bar, as we will see later on in relation to the figures. In some forms, when the point is coupled, in other words, in contact with the counterpoint, the roller is recessed between the piece known as the box and -6 the slider. It locks them together and, as it has no possibility of movement, it keeps them joined together and fixed. The piece known as the bar may be moved by an external actuating mechanism and has a rabbet where the roller can be housed. When that rabbet passes below the roller, the roller "falls" and then the slider and the box cease to be locked together. The point is therefore free. At that moment, the roller locks the bar with the slider and, as the bar carries on moving, it drags the slider and this in turn drags the point. When the point reaches the open position, it is locked, and the roller rises up towards a groove that is in the box, again locking the slider with the box, and so the point also remains locked in that position. If it is wished for the point not to remain locked in the open position, it suffices to make an adjustment in that regard without having to change any piece, simply by means of adjustment. The actuating system for carrying out the points change may be of the hydraulic type and in this case the bar-slider unit is going to act as a hydraulic cylinder when it receives fluid from the outside. As the maneuvering and retention stresses do not usually exceed 900 kg, a low pressure circuit can be used. As has been stated earlier, embodiments of the invention may be applicable to a movable point frog, which is displaced from one position to another (open-closed) by means of the bolting system forming the object of the invention, in which the movable point is replaced by a switch. With embodiments of this arrangement, the following advantages may be obtained: - There is no need to drill the counterpoints. - The changes in the gauge do not affect its tightening. - There is no need for greasing or maintenance. - It minimizes the maneuvering stresses due to using rolling elements and anti-friction materials. - Its adjustment is done by means of threaded elements. - The point is locked in the two positions (open and closed) or just in the closed position, the bolt can be trailable, according to the wishes of the railway authorities. - The expansions of the tracks are not affected.

-7 - It is simple to fit and remove on the track. Certain improvements in the structure offered by the bolt bodies are also considered: The bar carries two rabbets in which may be housed partially and sequentially two horizontal rollers which move in respective transversal sheaves of the slider, instead of there just being one roller as occurs in the previous embodiment. By using this second roller, the distance which the point moves manages to be increased up to 160 mm and, moreover, a smoothness and precision are achieved in the mechanism, as we have already said. When the rollers are housed in the rabbets of the bar, the slider moves freely within the box, the distance between the rollers being less than that existing between the rabbets of the box. The two horizontal rollers fix the closing and opening positions of the corresponding point. The closing position is obtained with the bar in the withdrawn position and the closing roller (the rear or outer one of the unit) being advanced with respect to the rear rabbet of the bar and with the rear rabbet of the box. If the bar is made to advance in order to carry out the change of points, the closing roller falls into the rear rabbet of said bar and the opening roller is simultaneously forced to move by the roller, dragging along the slider until the forward rabbet of the box is reached, at which moment this opening roller is forced to leave the rabbet of the bar and become housed in the forward rabbet of the box. When the bar advances even more, the locking in the maximum separation of the point with respect to the counterpoint is achieved and maintained. This arrangement of rabbets and two rollers leads to a functioning that is very smooth and secure in both positions. The supports that are found at the forward end of the sliders and integral with them force the point under pressure against the counterpoint in the closed position, which is carried out by means of some plate springs fitted in the support and which push on a yoke which in turn pushes on a tightening roller which makes direct contact with the appendage which is integral with the point. This tightening roller is fitted horizontally and may be moved vertically by rolling on a vertical plaque of the appendage, as a result of the support carrying the plate spring including a coaxial annular piece freely rotating in slider and with a radial arm which materializes the thrusting piece.

-8 In order to avoid undesired vibrations when trains pass, the appendage integral with the point may include a lower extension where a horizontal roller is fitted which is able to be housed below a projection of the box, thus immobilizing the point in the closed position. Provision has also been made so that, in order to facilitate the elevation and descent movements of the horizontal opening and closing rollers during the advance or withdrawal movement of the bar, the rabbets of the latter may be made to be wide, therefore having a greater size than those of the box which are semicylindrical. In this way, the roller guided by the slider can easily fall into the rear rabbet of the bar, and at the same time the opening rabbet is more easily raised when the forward rabbet of the box is reached in the advance of the bar in order to reach the open bolting position. BRIEF DESCRIPTION OF THE DRAWINGS In order to facilitate the understanding of the characteristics of embodiments of the invention and forming an integral part of this descriptive specification, some sheets of plans are attached in which the figures the following has been represented on an illustrative and non-limiting basis: Figure 1.- Is a longitudinal elevation view, transverse to the line, of the independent bolt bodies joined together by means of the intermediate bar, which interact in the bolting system for points changing in accordance with a first embodiment of the invention, being coupled to the respective tracks of the railway line. Figure 2.- Is an elevation view of one of the two bolt bodies in the closed or contact position of the point with respect to the fixed rail or counterpoint, and of the locking of the mechanism. Figures 3 to 5.- Are views similar to figure 2, of different intermediate positions from which the points change starts. Figure 6.- Is a view similar to figures 2 to 5, once the points change has taken place and the position has been reached of locking the mechanism in open point. Figure 7.- Is a partial view in perspective of that shown in figure 6. Figure 8.- Is a partial view in perspective from the right side of figure 7. Figure 9.- Is a partial view in perspective from a raised point of the same figure 7, but in the points closed position, according to figure 2.

-9 Figure 10.- Is a view similar to figure 1 of a bolting system for points changing according to a second embodiment which includes some improvement in the bolt bodies. Figure 11.- Is an enlarged view of one of the bolt bodies of figure 10, in the closed position with locking, where the point is forced under pressure against the counterpoint. Figure 12.- Is a view similar to figure 11, in an intermediate position after starting the opening operation when the bar advances, in this second embodiment. Figure 13.- Is a view similar to figure 12 in another more advanced phase of opening, in this second embodiment. Figure 14.- Is a view similar to figure 12 in the final position of opening with locking, in this second embodiment. DETAILED DESCRIPTION Making reference to the numbering adopted in the figures and especially in relation to figure 1, we can see how the bolting system for points changing in railways and/or movable point frogs, which the invention proposes, consists of two independent bolt bodies referenced with 1 and 2, one for each point 3 or movable rail, each of them being suspended from the shoe of the counterpoint 4 or fixed rail and joined together by the intermediate bar 5 adjustable in length. As these bodies comprise the same pieces and their functioning is identical though conjugate, since when one opens the other closes and reciprocally, in what follows and in figures 2 to 9 we will refer to just one of these bodies, specifically the one on the right which is referenced with 1. Each body 1 is suspended from the shoe 6 by means of a fastening achieved with clamps 7 and 8, which avoids the need to drill the rail 4. Nevertheless, other fastening devices can also be used. The clamps 7 and 8 are joined to the piece known as the box 9 by means of screws or threaded studs 10 and locking nuts 11, passing through the holes made in them and in the lugs 12 of the box 9. The box 9 offers the hole 13 (figure 8) for passage of the slider 14 which runs transversely to the fixed rail 4 and which offers a tubular configuration since the bar 15 passes through its center.

-10 The bar 15 of the bolt body 1 (the one on the right of figure 1) is connected to the actuating mechanism of the points change, of the hydraulic, mechanical or similar type, and its movement produces the opening or closing of the point according to conjugated movements in both bolt bodies, since the bars 15 are those which are joined together via the intermediate bar 5 (figure 1). Fixed in the slider 14 is the support 16 which is integral above with the appendage 17 to which the point 3 is attached. When the slider 14 is linearly displaced the point 3 does so at an angle in order to move closer to or further away from the counterpoint 4. The transmission of this movement is done by means of the roller 18 arranged horizontally and transversely in the interior space of the box 9 where it can be displaced vertically in a transversal sheave of the slider 14, resting in turn on the bar 15. The box 9 has two separated grooves 20 and 21 in its upper wall in which the roller 18 can be partially housed in the most elevated position of the latter, corresponding to the locking of the point 3 in the closed position (figure 2) or open (figure 6). The reference 22 designates the semi-cylindrical rabbet which the bar 15 presents in its transversal arrangement, in which the roller 18 is able to be partially housed so that it can thus be transported from one position to another dragging the slider 14 with it. When it is housed in said rabbet (figures 3 and 4), it remains tangential to the upper wall of the box 9 and can displace the slider 14 when the bar 15 does so. With this arrangement the functioning is as follows: Starting from the locking position of figure 2 where the roller 18 is secured in the groove 20, it can be seen how it in turn rests in the bar 15 remaining thus until the mechanism connected to the bar 15 is acted on in order to make the points change. In these conditions, when the advance movement of the bar 15 towards the left of figure 2 begins, the rabbet 22 reaches the point in which it faces the roller 18 and this falls out of the groove 20 of the box 9 as seen in figure 3. As the bar 15 continues to advance, the slider 14 does so simultaneously because the roller is dragging it due to the fact that it at all times remains in the sheave 19 (as shown in figure 4).

- II An instant prior to the roller 18 occupying the position of figure 5, it reaches the groove 21 of the box 9 and simultaneously reaches the point of making contact with the box 9 and the buffer 23 secured to the right part of the slider 14 and the movement of the latter is halted. This movement causes the roller 18 to rise up as shown exactly in figure 5. As the bar 15 continues to advance the system becomes locked because the position of figure 6 has been reached which prevents the roller 18 from descending. When the same thing occurs in the opposite direction for a new points change, the movements are in reverse though it is the buffer 24 on the left of the slider 14 which makes contact with the box 9 at the moment in which the roller 18 meets up with the groove 20 of the box 9. In this case, it is the needle 3 which determines the maximum travel by interacting with the counterpoint 4. As can be seen more clearly in figures 7 and 9, the attachment of the support 16 with the appendage is carried out by means of the pulley-wheel 25 arranged in the vertical pin 26 inserted in said support 16. The pulley-wheel 25 moves in a slot 27 of the appendage 17. The expansion due to temperature changes of the point 3 are corrected owing to the fact that the drag is carried out with the pulley-wheel 25 which can roll. The appendage 17 is attached to the point 3 by means of the screw 28 passing through a hole in the shoe of the point 3 (see for example figure 2). The point 3 is seated and slides during its movements of the points change on a guide 29 since the mechanism is located between two sleepers or in a hollow sleeper as we have said earlier. As can be seen in figure 2, when the point is closed or pressing against the fixed rail or counterpoint 4, it does so under pressure by means of springs 30 belonging to the regulating piece 31 for tightening of the point 3 with respect to the counterpoint 4. In this position (figure 2) the support 16 remains slightly separated from the buffer 24 for regulating the thrust, while as can be seen in figures 3 to 6 when the point 3 becomes separated from the counterpoint 4 the support 16 makes contact with the buffer 24 by the action of these springs 30. Making reference now to figures 10 to 14 and in particular with regard to figure 10, the improvements introduced into this second form of embodiment are located in the structure which each one of the bolt bodies 32 and 33 presents, each one of them being linked to the respective movable rail or point 34 and secured to the shoe 35 of the respective fixed rail or counterpoint 36.

- 12 Both bolt bodies 32 and 33 are joined to each other by the tie rod or intermediate bar 37 which is adjustable in length and whose ends are attached via a cardan joint to the bars 38 which traverse them axially. The free end of one of the bars 38 is connected to an external mechanism for simultaneously carrying out the movement of the points 34: one moving them away from the counterpoint 36 and the other moving them closer to it. In figure 10 the point on the right, governed by the bolt body 32, is in the closed position and that of the bolt body 33 is in the open position. As both bolt bodies 32 and 33 are the same, though mounted in a symmetrical position and therefore formed by the same elements which function analogously and in such a way that when one opens the other closes, here too we will look at the structure in detail for just one of them: the right one which is referenced with 32. In the first form of embodiment of figures 1 to 9, there existed this same arrangement, as well as the general structure of the bolt bodies 32 and 33 where the box 39 intervenes which is secured to the shoe 35, on one side with the clamps 40 and screws 41 and on the other side with the projection 42 formed in it. The box 39 is tubular and moving in its axial gap is the slider 43, also tubular and sliding inside that is the bar 38 referred to above, connected to the actuating mechanism for the points change. Fixed in the slider 43 is the support 44 formed by an annular piece 45 coaxial and enveloping the slider 43 and linked linearly to its end though with free rotation; and a radial arm which materializes a thrusting piece 46 to which is connected an appendage 47 integral with the point 34 (though these means of union have not been represented due to being conventional). When the slider 43 moves linearly, the point 34 does so since it is integral with it, in order to move closer to or further away from the counterpoint 36. This movement was effected in the first embodiment with a single horizontal roller 18 which moves between two fixed positions in which it is able to remain recessed. In order to improve this functioning and make it smoother and more precise, in accordance with this second form of embodiment, provision is made for the bar 38 to include two wide rabbets 48 and 49 in which it is possible to house the respective rollers 50 and 51 which move vertically in separate transversal sheaves 52 and 53 of the slider 43. These rollers in turn interact - 13 with the semi-cylindrical rabbets 54 and 55 of the box 39. Depending on the relative position of the rollers 50 and 51 with respect to the wide rabbets 48 and 49 of the bar 38 and of the semi-cylindrical rabbets 54 and 55 of the box 39, the dragging of the slider 43 is or is not obtained when the bar 38 is slid, as we will see further below. Figure 11 shows the position of the point 34 coupled to the counterpoint 36 and locked or bolted, corresponding to the initial or starting position as far as achieving the change of points as shown in figure 14. The bar 38, which is in an end position (towards the right) with respect to the fixed position of the box 39, prevents the falling of the closing roller 50 since it is retained due to resting on the cylindrical part of the former and therefore the slider 43 is mechanically joined to the box 39 and is thus kept in this locking or bolting position because the thrusting piece 46 maintains the point 34 against the counterpoint 36. An elastic contact pressure is obtained due to the fact that the support 44 and more specifically its thrusting piece 46 acts on some plate springs 56 which in turn transmit the effort to a spring-holder 57 threaded to the yoke 58 which supports a horizontal tightening roller 59 which is the element that presses directly on the vertical plaque 60 of the appendage 47 integral with the point 34, and keeps it firmly locked. When the bar 38 is moved by about 30 mm to the left (position of figure 12) when the points change is carried out, the closing roller 50 falls into the wide rabbet 48 of the bar 38 being released from the semi-cylindrical rabbet 54 of the box 39 and the entire mechanism is unlocked. In figure 13, the bar 38 continues advancing and it is the opening roller 51 which drags the slider 43 since the closing roller 50 passes tangentially to the upper wall of the box 39 and does not do any dragging at all. The point 34 continues to separate from the counterpoint 36. The bar 38 continues to move until the opening roller 51 meets the sheave 55 which the box 39 has in its front zone, occupying it and permitting the bar 38 to pass beneath (see figure 14). In this position, the point 34 becomes locked again, this time in the open position. The intermediate tie bar 37 which joins the two bolt bodies 32 and 33 transmits the movement to the second body 33, with which the latter moves in a manner symmetric to the first (when one opens the point 34, the other closes it).

-14 The use of plate springs 56 in series, in order to press the point 34 against the counterpoint 36, permits considerable tightening efforts to be achieved between these elements with little travel. The location of those plate springs 56 is more advantageous than that considered in the first embodiment, where there existed springs 30 located at the height of the slider 14 (figure 3) and the torque caused by the tightening between the point 3 and counterpoint 4 prevented the necessary displacement of the springs 30 for their correct functioning. By locating them now at the height of the point 34, the torque does not affect the plate springs 56. In order to permit the free expansion of the point 34 (in the longitudinal direction with respect to the track and perpendicular to the plane of the attached drawings) the thruster 46 is a freely rotating piece with respect to the slider 43 since it is linked to the freely rotating bushing 45. If the point 34 advances due to expansions, it pulls on the appendage 47, this on the yoke 58 and the yoke 58 on the spring-holder 57. The spring-holder 57, which is embedded in the thruster 47 with the anti friction bushing, longitudinally pulls on the thruster 46, forcing it to rotate. But the spring-holder 57 in turn rotates inside this anti-friction bushing, with which the tightening roller 59 is always in the horizontal position pressing on the plate 50 of the appendage 47, though it goes up and down rolling in it and therefore it maintains the tightening between the point 34 and the counterpoint 36. In the closed position of the point 34 (figure 11), it can furthermore be seen that the lower part of the appendage 47 includes an elevation roller 61 which fits below a lug 62 included in the box 39. With this, the oscillations of the point 34 produced by the passing of trains are prevented. It can also be stated that in accordance with embodiments of the invention the tightening between the point 34 and the counterpoint 36 is regulated by threading the yoke 58 to a greater or lesser degree inside the spring-holder 57. In figure 11 the spring-holder 57 is more introduced into the thruster 46 adopting a floating arrangement owing to the elasticity of the plate springs 56, while in figure 14, since the point 34 is separated, the spring-holder 57 is displaced towards the right by the elastic pressure of the plate springs 56, until it meets up against the closing cover 63 threaded to the mouth of the thruster 46.

- 15 In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e., to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the method and apparatus.

Claims (7)

1. A bolting system for points changing in railways comprising two independent bolt bodies, one for each point or movable rail, linked by an intermediate bar of adjustable length and arranged transversely to the line, said bolt bodies being simultaneously displaced by a device having mechanical or hydraulic actuation, each bolt body being suspended from the shoe of the counterpoint or fixed rail and formed by a box provided with means of fastening to the shoe of the counterpoint; there existing a slider which slides within the box and which at its end bears a support integral with it to which is secured the point; provision having been made for the displacement of the sliders and therefore that of the points to be effected by means of separate bars which axially traverses the sliders and with which they are able to be axially locked; each slider adopting two fixed positions with respect to the respective box, corresponding to the ends of travel of the angular movement of the point; the respective bars of each bolt body are joined together by said intermediate bar of adjustable length and one of them is in turn joined to the actuating device; each bar includes two rabbets wherein separate horizontal rollers which move in respective transversal sheaves of the slider can be partially housed, being able to move freely within the box in this position; the supports linked to the sliders and which press the respective points against the counterpoints in the closed condition, do so via some plate springs which push on a yoke and this on a tightening roller against an appendage integral with the point; the support linked to each slider is a freely rotating piece with respect to the latter, due to including an annular piece coaxial with a radial arm which defines the thrusting piece bearing the plate spring, the tightening roller being fitted horizontally in the yoke and being able to be displaced vertically by rolling on a vertical plaque of the appendage; wherein the appendage integral with the respective point includes a lower extension with a horizontal roller which is able to be housed beneath a projection of the box eliminating the vertical oscillation of the point in the closed position.

2.- The bolting system for points changing in railways according to claim 1, wherein the support joining the slider to the point has an insertion hole for the slider and integral with the latter is an appendage secured by means of a screw -17 to the shoe of the point and the appendage being connected in articulated fashion to said support by means of a pulley-wheel fixed to a vertical pin.

3. The bolting system for points changing in railways according to claim 1, wherein the support inserted in the slider has a small axial displacement assisted by springs which push it towards the buffer close to the fixed rail or counterpoint in order to keep the point in contact with the counterpoint and said springs being supported in a tightening unit fixed in the end zone of the slider.

4. The bolting system for points changing in railways according to claim 1, wherein the box is provided with two semi-cylindrical rabbets at a greater distance between each other than those of the bar in which they can be partially and respectively housed, fixing the closing and opening positions of the corresponding point, the closing position being determined in the withdrawn condition of the bar due to the closing roller being advanced with respect to the rear wide rabbet of the bar and within the rear semi-cylindrical rabbet of the box; the opening position being determined as the bar initially advances and the closing roller housed in the rear cylindrical rabbet of the box falls into its rear rabbet, and the opening roller continuing in its wide rabbet of the bar without reaching the forward semi-cylindrical rabbet of the box, until, having reached the latter, it is forced to overcome the rabbet of the bar and be housed in the forward semi-cylindrical rabbet of the box, continuing thus until completing the opening travel of the bar where the point reaches the locking in its maximum separation from the counterpoint.

5. The bolting system for points changing in railways according to claims 1 to 4, wherein the tightening of the point against the counterpoint is adjustable due to the yoke being threaded in the spring-holder.

6. The bolting system for points changing in railways according to claim 1, wherein the wide rabbets of each bar are widened or of larger size than those of the box in order to freely permit the descent of the closing roller as the bar advances until the same roller guided by the slider exceeds the rear semi cylindrical rabbet of the box; and the opening roller is more easily raised due to reaching the forward semi-cylindrical rabbet of the box as the advance of the bar continues.

7.- A bolting system for points changing in railways substantially as herein described with reference to the accompanying drawings.