Technical field

The technical field of the present invention relates to railway devices that manage the movement of the tracks of a switch point.

In particular, the invention refers to an innovative coupling assembly for the manoeuvre and the control, the first one transferring the motion of the tie rods to the blades for the movement thereof, while the second one manages the control thereof. Such an assembly, in accordance with the invention, results particularly long- lasting and not much affected by wear phenomena such as fretting .

Background art

Along the tracks of a train turnout areas have long been installed, which allow the train to vary its route, diverting to a deviated branch. To that aim, the so-called switch points have been foreseen, as for example shown in figure 1A of the prior art.

The switch point shows a correct layout and a deviated branch. The deviation is allowed thanks to a structure of the tracks that, always as shown in figure 1A, comprises a left blade, placed in proximity of its edge rail, or stock rail, and a right blade placed in proximity of its edge rail, which forms the correct layout. The term ^blade" means in technical jargon a track whose end is progressively always more tapered to allow the wheel of the train to engage on it. The blades (the right and the left ones of figure 1A) of the switch points are mobile for an extended section of their length and are moved through an appropriate manoeuvre apparatus that terminates with two tie rods coupled each one to a blade. The translation of the tie rods, thanks to an appropriate manoeuvre apparatus, causes a translation motion of the right and left blades, thus moving the switch point from right to left or vice-versa.

Figure 2A shows a traditional coupling system that serves to actually connect the tie rods to the blade, the figure shows a single coupling system since the second one, that is the one that couples with the other opposed blade, is absolutely specular. The figure in question shows a coupling element (Z) , called leg in the technical jargon, which, through bolting connects rigidly to its blade (A) through a flat connection face. The leg is then moved through a coupling hook (Q) , in turn connected to the tie rod (not shown in the figure for descriptive simplicity purposes) . The leg (Z) is holed axially to allow the passage of a pivot (P) that serves as connection element between the hook (G) and the leg (Z) . In this way, such a kinematic chain of transmission of the motion is created that, during the translation of the tie rods, the hook (G) has the possibility of rotating with relation to the pivot (P) and transmit the translation to the leg (Z) . In this way, the blade is moved to come close to or move apart from its stock rail.

Figure 3A, for clarity purposes, shows an overall view and highlights the two tie rods (T) that connect to the two legs Z (the right and the left one) .

Figure 4A, always of the Prior Art, shows for clarity purposes the detail of the leg (Z) with the pivot inserted to which the hook (G) connects, in this case constituted by an arm with an eyelet (O) to one of its ends and connected to the tie rod by the opposite end. The pivot is therefore inserted in the eyelet (O) .

The solution of figure 4A is therefore substantially identical to that of figure 2A except for the fact that the hook foresees the eyelet and is emerging towards the top with respect to the tie rod to which it connects. This solution is used when, as per figure 4A, the tie rods are placed under the sleeper (see figure 3A) , while the solution of figure 1A is used with the tie rods more or less at the same level of the leg.

Independently of the solution of the background art used, this however suffers of various technical inconveniences that will be mentioned hereinafter.

Above all, the first problem that can be found is that the traditional systems described are particularly subject to phenomena of sudden breakage essentially due to fretting or surface wear. The relative movement between two components, even if with minimal values of sliding comparable to micro vibrations, brings to the progressive removal of material and therefore to the progressive reduction of the resistant section of the components. The contact points, on which a great precise pressure acts, can arrive to plastic deform and, even, to melt, thus being removed and being taken away. It is clear that the progressive reduction of resistant section inevitably brings to breakage. The systems described in figure 1A and 4A are particularly subject to fretting since they are not only not optimized with appropriate choices of idoneous material but also because they structurally do not allow the so-called "washing" of the components in. contact. By washing it is intended the removal of the residues of material due to rubbing, generally called shavings. The solutions of the Prior Art described have such a structural shape that the residues (like also the eventual dirt present in the operating environment and blown in between the components by the passage of the trains) remain trapped between the components and the expulsion thereof is not favored, therefore accelerating the wear and amplifying the negative effect of the fretting itself during the reciprocal rubbing between components mutually in contact. For example, the eyelet of figure 4A does not allow an expulsion by gravity of the impurities that are formed inside it and the same situation is present also in the solution, of figure 1A.

Another technical inconvenience concerns the fact that the solutions described of the background art fail to compensate in an efficient way excessive dimensional variations due to thermal effects. For example, the solution of figure 4A, in case of thermal expansion of the blade due to the high temperature of the operating environment, allows a relative movement between hook (G) and pivot thanks to the sliding of the eyelet (O) . Nevertheless, the sliding is limited to the dimension of the pivot selected and therefore, in case of high extensions, dangerous phenomena of tensioning are inevitably triggered for the integrity of the system itself. The same considerations obviously apply for the solution of figure 1A, It is clear that in sultry areas the dimensional extensions are significant and it is impossible to think of projecting taking into account specific dimensions for each operating environment,

Moreover, in the case of thermal .expansions that bring to very irregular distortions, for example inflexions of the blades, the system of figure 1A and 4A is the cause of the occurrence of further tensions. The hook (G) , (see for example figure 1A) in case of inflexion of the blade, opposes to said inflexion by acting against the pivot. Not only does all this worsens fretting by local increase of the pressures, but it also triggers additional tensions that can bring to breakages.

Basically, the degrees of freedom of the systems of the Prior Art are inadequate to cover the several variants linked to the working environment, the whole not only amplifying the fretting but also causing additional tensions that contribute to the breakage,

The problem of the limited degrees of freedom of the current solutions is clear also in the case in which a lifting of the rail takes place (for example following a substitution of normal support cushions with roller cushions) . This substitution brings to a difference of elevation (increase of the positioning height) of the order of the 4mm to which holing and alignment errors of the components during all the mounting phase of the iron line and of the switch point should inevitably be added. If such misalignments cannot be compensated by the degrees of freedom allowed by the coupling system, then tensional states occur that can accelerate much the appearance of a breakage condition.

German document DE102008060229 is considered the document of the background art closest to the invention. It describes the preamble of claim 1 or of claim 19. Such document describes a structural solution subject to fretting phenomena since, during the functioning, the residue material ha3 no way of coming out.

Disclosure of invention

It is therefore the aim of the present invention to provide a coupling assembly 1 that solves at least in part said technical inconveniences.

In particular, it is the aim of the present invention to provide a coupling assembly 1 structured in such a way as to reduce the fretting, allow the washing, compensate errors and tolerances of mounting and thermal variations, so as to reduce as much as possible, and preferably annul completely, all the eventual tensional states induced. These and other aims are therefore reached with the present assembly 1 in accordance with claim 1,

The assembly (1) comprises a group of manoeuvre (3) suitable for moving the blade to which it is connected. In particular, the group of manoeuvre (3) foresees a coupling element (11) connected to the blade on one part and connected to a manoeuvre hook (10) on the opposite part. The connection is made through a seat (15) obtained at an end (14) of the coupling element and into which an end (13) of the manoeuvre hook (10) engages slidingly and rotatably. The sliding in the seat guarantees a certain tolerance to the length variations of the blade by means of the thermal excursions. When the blade lengthens it drags behind it the coupling element that can however slide freely with respect to the manoeuvre hook to which it is connected. The seat (15) is further open on one part in such a way as to allow the fall outside of eventual external residues and/or fretting residues interposed in the connection. Basically, dirt and fretting residues fall by gravity, allowing the so-called "washing". Last, the end (13) further presents a surface (17, 17' ) of contact with the sliding seat (15) which has a circular shape according to a section plane coinciding with the medium plane passing longitudinally along the length of the manoeuvre hook (10) and further a curve that develops in the direction of the longitudinal axis (300) of the end (13). This contact, generally just one point or contact area, guarantees different rotational degrees of freedom to the coupling element 11 with respect to the manoeuvre hook. The coupling element can therefore freely orientate on the spherical surface according to the mounting tolerances and of the dimensional variations due to thermal changes. The whole for the benefit of the reduction of the fretting phenomena and of the internal tensions .

Advantageously, the sliding seat (15) is a circular section one in the medium plane passing longitudinally along the length of the manoeuvre hook (10) .

Advantageously, the seat (15} is longitudinally passing .

This has the advantage of actually allowing a very high translatability of the coupling element with respect to the manoeuvre hook since, being the sliding seat open from both parts, there actually does not exist a stop that limits the translation as instead happens in the background art.

Advantageously, the manoeuvre hook is inserted in the seat through said opening for the fall of the external and fretting residues.

This solution is structurally simple.

Advantageously, the surface (17) of contact is a roller (17) connected to the end (13) ,

This allows a separate workability of the roller with specific tolerances and an appropriate selection o.f materials .

Advantageously, the surface (17) of contact is of a plastic material and the sliding seat is of a metal material and preferably the surface of contact is of Polyamide 66 and the seat (15) is of nickel-chromium- molybdenum steel of the 39NiCrMo3 type.

The metal-plastic coupling has the advantage of reducing the fretting significantly.

A metal-metal coupling could anyway be used, for example steel with steel. In particular, the external surface can be realized of the same steel of the seat 15, that is of nickel-chromium-molybdenum steel of the 39NiCrMo3 type. Being the materials identical among them and particularly hard, they will suffer the same deformations , thus reducing much the fretting.

Advantageously, a tie rod (20) is foreseen, which engages with the manoeuvre hook (10) in such a way that a reciprocation of the tie rod (20) is transmitted to the manoeuvre hook (10) .

Advantageously, said connection is obtained through a cavity (18) obtained in correspondence of the belly of the manoeuvre hook and that forms a front tooth (16) and a back tooth (16'), said cavity (18) overlapping on a complementary protuberance (23) obtained on the back of said tie rod (20) and such as to form a counter-tooth (20) that goes in contrast against the front tooth (16) and a back shoulder (22) that goes in contrast against the back tooth ( 16' ) .

Advantageously, the coupling between the front tooth

(16) and the counter-tooth (20) takes place with a predetermined vertical clearance, preferably 3mm, in such a way as to allow a pre-determined lifting of the manoeuvre hook with respect to the underlying tie rod (20) .

This lifting allows to compensate overall risings of the switch point, for example of the blades, due to structural tolerances or substitutions. Advantageously, a group of control (4) can be further foreseen, coupled with the group of manoeuvre (3).

Advantageously, in that case, the group of control

(4) is placed beside the group of manoeuvre and is dragged by the motion of the group of manoeuvre through the blade (A) .

The group of control verifies the correctness of the manoeuvre in progress.

Advantageously, said group of control (4) comprises a control element (50) connected to an arm (70) through a seat (60) obtained at an end of the control element (50) and into which an end (71) of the arm (70) engages slidingly, the seat (60) being further open on one side in such a way as to allow the fall outside of eventual residues and/or residues of fretting interposed in the connection and in which the end (71) is rotatable with respect to the arm (70) .

Advantageously, the arm (70) foresees a pivot on which the end (71) is mounted rotatataly.

Advantageously, the seat (60) is longitudinally passing .

Advantageously, the seat (60) is with overturned u- shaped section and the end (71) presents at least two flat faces opposed so as to be coupled slidingly in said overturned U-shaped section.

Advantageously, the seat (60) is of metal and the end (71) is of plastic and preferably the seat is of nickel-chromium-molybdenum steel of the 39NiCrMo3 type with the end (71) of Polyamide 66.

Advantageously, it is here described just the group of manoeuvre (3) of said assembly, for moving a blade (A) of a switch point.

It is in fact applicable to any type of switch point and comprises coupling element (11) connected to a manoeuvre hook (10) through a seat (15) obtained at an end (14) of the manoeuvre hook (10) engages slidingly and rotatably, the end (13) further presenting a surface (17, 17') of contact with the sliding seat (15) which has a circular shape according to a section plane coinciding with the medium plane passing longitudinally along the length of the manoeuvre hook (10) and further a curve that develops in the direction of the longitudinal axis (300) of the end (13), characterized in that the seat (15) is further open on one side in such a way as to allow the fall outside of eventual external residues and/or residues of fretting interposed in the connection. Last, it is also here described an alternative solution applicable specially in the group of control (4) to control the correct movement of a blade (A) of a switch point. This solutions allows exactly in the same way to solve said technical problems, especially the one relative to fretting. In particular, an opening allows the fall outside of residues.

In that case, the group of. control (4) comprises a control element (50) connected to an arm (70) through a seat (60) into which an end (71) of the arm (70) engages slidingly and rotatably, wherein the end (71) is mounted rotatably with respect to the arm (70), characterized in that the seat (60) is further open on one part in such a way as to allow the fall outside of eventual external residues and/or residues of fretting interposed in the connection.

Advantageously, said seat (60) is open from the bottom and laterally, the arm (70) foreseeing at the head said end (71) constituted of a dice which is mounted rotatably on a pivot (72) .

Advantageously, said seat (60) has an overturned U- shaped section, the dice being of a quadrangular shape and preferably of "Polyamide 66".

Brief description of drawings

Further features and advantages of the present assembly, according to the invention, will result clearer with the description that follows of some preferred embodiments, made to illustrate but not to limit, with reference to the annexed drawings, wherein:

- figures from 1A to 4A describe the Prior Art;

- figure 1 shows an axonometric view of the overall assembly 1 of manoeuvre and control to transmit and control the movement of the blades of the switch point _/ - figure 2 shows in an axonometric view the detail of a single right or left assembly;

figures 3 and 4 are the lateral views respectively of the assembly relative to the right open blade and to the left close blade;

- figure 5 shows, always in an axonometric view, just the group of manoeuvre 3;

- figure 6 shows an exploded view of just the group of manoeuvre 3;

- figure 7 shows a constructive detail of the roller 17;

- figure 8 shows an axonometric view of the group of control 4;

- figure 9 shows an exploded view of the group of control 4.

Description of some preferred embodiments

Figure 1 shows in a perspective view an assembly 1 of coupling to the blades for the manoeuvre and. the control thereof in accordance to the invention. The figure shows the two tie rods 2 and of which one that connects to a right assembly 1' and the other one that connects to the left assembly 1'', identical and specular between them. Each right and left assembly, as clarified hereinafter, foresees a group of manoeuvre 3, suitable for the movement of the blade to which it is connected, and a group of control 4, which is simply dragged in the movement obtained thanks to the group of manoeuvre and is suitable for controlling if the operation of translation of the blades is taking place correctly.

As per the background art, the length of a section of switch point (therefore the length of the blades) is high and can exceed without problems the 10 or 20 meters according to the need. For controlling a correct translation of the blades of such a high length, it is necessary to interpose along the section further assemblies, such as that of figure 1, but generally constituted just by the group of manoeuvre 3 and therefore lacking the group of control 4, since it is already arranged at the head and just one of them is enough. The subsequent sections can foresee right and left assemblies lacking group of control.

Going on with the structural description of the invention, figure 2 shows an assembly of manoeuvre and control, indistinctly right or left (1' or l' ^r ).

In particular, figure 2 shows, as already said, the assembly that comprises the group of manoeuvre 3 and the group of control 4.

The group of manoeuvre 3 is isolated for descriptive simplicity in figure 5. It comprises a manoeuvre hook 10 that couples with the leg 11. The leg 11 foresees a flat front surface 12 that connects to the blade 100 through ordinary bolts. The opposite end 14 Is Inserted instead on the hook 10. To that aim, the leg 11 is generally L-shaped in such a way that a part serves as connection to the blade and the opposite part is directed towards said hook. In particular, such a connection, in accordance with the invention, takes place through the insertion of the end 13 of the hook in a circular seat 15, open on both parts, and obtained precisely in the end 14 of the leg. The circular shape of the seat 15 creates a rotational hinging in the medium plane passing longitudinally along the length of the hook 10. The end 13 presents one of its parts 17 (see figure 6) in the shape of a spherical cap. More precisely, a ring 17, called roller, is interposed, in the shape of a barrel and with an external surface that is substantially spherical or anyway with a curve that develops in the direction of the axis 300. The ring 17 can be rotatable or fixed with respect to its mounting axis. This external surface is in fact the surface of contact with the internal surface of the respective seat 15 when the two components are coupled. All this, that is the sphericity of the roller, has the technical effect of making that the coupling between the leg 11 and the hook 10 takes place with a certain rotational degree of freedom between the two components also in different places to the medium one that passes along the length of the hook 10. Basically, rotations of the blade due to mounting tolerances, cushion change and/or thermal variations are recovered through the possibility of rotational motion, practically in all the possible directions of the leg 11 with respect, precisely, to the hook. In particular, the seat 15 has the possibility of rotating on the spherical surface of the ring 17, therefore adapting itself to several different positions. The whole, obviously, for the benefit of a significant reduction of the tensions. Figure 7, for greater clarity, extrapolates the detail of the roller in order to highlight said spherical surface 17' and shows the rotation axis 300.

Always as shown in figure 5 and 6, the hook 10 is connected to the tie rod 20 that confers the right- left/left-right alternate motion to the assembly. The connection between said two components is obtained through a first tooth 16 that engages in a complementary tooth 21 of the tie rod 20. On the opposite part a tooth 16' engages in a relative seat 22. In this way, the dragging of the tie rod 20 conducts in translation also the hook 10. Basically, the solution of figure 5 shows a sort of cavity 18 obtained in the hook 10 that overlaps to a protuberance 23 of the underlying tie rod. Figure 6 shows a folded metal sheet 24 that locks up between them the two elements .

As highlighted in figure 5 and in figure 6, the further technical advantage of this solution is that, with respect to the background art, there is a significant reduction of the fretting. In fact, the coupling between the component 11 (the leg) and the component 10 (the hook) is operated through the end 17 that is inserted in an opening 15. Said opening is precisely open from the bottom, in the sense that it is a circumference arc and, due to the L-shaped structure of the leg, the opening is directed towards the bottom. This inevitably favors the fall by gravity of all the residues that are formed due to the rubbing action between the parts and, above all, favors the exit of the impurities that get inside it. Basically, this solution favors the so-called "washing" introduced in the background art.

Another significant advantage of this solution, with respect to the background art, is that the seat 15 actually forms a sliding channel. In that sense, an eventual expansion or retraction of the blade due to strong thermal excursions are followed by an equivalent translation of the leg 1, which is sliding on the end 13 of the hook along, precisely, the longitudinal axis 300 of the seat 15. In this way, also the tensions introduced by strong thermal gradients are efficiently compensated.

Further, precisely in order to annul the fretting, an adequate ' coupling between the characteristic materials of the component in reciprocal contact has been studied. In particular, it has been surprisingly found that a contribution of reduction to the fretting lays on the choice of a ring 17 of "Polyamide 66" coupled with a nickel-chromium-molybdenum steel of the 39NiCrMo3 type.

In general, the metal-plastic coupling has a preventive effect on the fretting. This is because the soft material, that is the plastic, by deforming itself under the action of pressure, impedes the plastic deformation and the detachment of fragments that is characteristic of the coupling between materials of different nature. The same characteristic of deformation of the Polyamide, in the presence of eventual shavings or impurities blown in between said components to the passage of the trains, annuls the process of wear by fretting generated by the presence of impurities interposed.

Always figure 5, as also figure 3 and figure 4, highlight well the circular seat 15 coupled to the end 13. In this case, this type of coupling, though having a rotational degree of freedom, does not have by itself a high degree of translational freedom in vertical sense except by that own minimum coupling clearance between element 13 (in particular the ring 17) and the circular seat 15, Nevertheless, this type of structure solves this inconvenient precisely thanks to the coupling system between hook 10 and underlying tie rod 20. The teeth described 16 and 16' are inserted in their seats (in particular the seat 21) with a high clearance, and that can be constructively selected in such a way as to allow a vertical lifting of the arm 10 with respect to the tie rod 20 when the leg 11 is dragged upwards by the blade. For example, a value of clearance can be within a range between the 2mm and the 5mm and, preferably, of 4mm, and still better, of 3mm. The plate 24, which holds between them the components, serves as fulcrum so that, in said situation, the arm 10 in fact rotates to be lifted with respect to the underlying tie rod 20. The stop of the lifting is dictated by the contact between the tooth 16 with the 21.

Going on with the structural description of the invention, figure 8 shows the group of control 4 when mounted. Also this comprises a leg 50 having a flat surface that connects to the blade through specific bolting and an opposite end having a seat 60 in which the end 71 engages slidingly with an arm of control 70.

For clarity purposes, figure 9 shows the components separated in an exploded view. In this case, unlike the leg 11 of manoeuvre, the leg 50 of control foresees a seat 60 open from the bottom and laterally (that is passing as well), which however forms a sliding channel with the shape of an overturned U-shaped section instead of spherical cap. The arm 70 foresees at the head said end 71 constituted by a quadrangular dice which is mounted rotatably on a pivot 72. Also this dice, for the reasons mentioned above, is preferably of "Polyamide 66" coupled with a seat 60, preferably the entire leg 50, of nickel- chromium-molybdenum steel of the 39NiCrMo3 type.

For the same reasons mentioned above, this type of coupling reduces significantly the fretting. In particular, the open U-shaped section on one part allows the "washing" ^' . The coupling between a metal and a plastic material, specifically steel-Polyamide, reduces the production of residues. The sliding seat 60 allows to compensate thermal expansions and contractions in longitudinal direction, that is along the axis of the blade, while various errors of tolerance, lifting and other imprecisions can be compensated with a possibility of rotation of the leg 50 around the pivot 72 and a lifting of the leg. In particular, the leg rotates thanks to the possibility of rotation of the dice 71 with respect to the pivot 72 and, further, the same leg can be lifted with respect to the dice 71thanks to the overturned U- shaped guide _¾ in which it is inserted.

In use, therefore, is functions in the following way.

With reference to figure 1, the assembly 1, through the tie rods 2, drags the blades from left to right, for example (see direction, of arrow in figure 1 and 2) . The group of manoeuvre 3, comprising precisely the leg 11 and the hook 10, are activated through the tie rod 20 to which they are connected. The tie rod drags said group (both the right and the left one) in translation, bringing the blades to translate.

The group of control, eventually present only at the head of the switch point, is dragged in said motion and terminates with an end 200 (see figure 4) which, according to the position occupied, controls with specific sensors if the manoeuvre is being properly made or not. The sensorial part of said control is anyway known and therefore not explained with further detail here.

From what has been described, it is also clear that a use of a group of manoeuvre as per the background art is possible to which a group of control is coupled as described and vice-versa, therefore in an independent manner one from the other.