WO2014041519A2

WO2014041519A2 - Coupling assembly for operating control and movement of the blades of a switch point

Info

Publication number: WO2014041519A2
Application number: PCT/IB2013/058540
Authority: WO
Inventors: Felice GRANDE
Original assignee: Wegh Group S.P.A.
Priority date: 2012-09-14
Filing date: 2013-09-13
Publication date: 2014-03-20
Also published as: EP2895372A2; WO2014041519A3; EP2895372B1; ITFI20120182A1

Abstract

The present invention refers to an assembly (2, 3) for a control and manoeuvre apparatus (1) of the blades (A, B) of a switch point and comprising: A coupling element (3) to the blade (A, B) comprising a surface (3') of connection to the blade and, on the opposite part, a seat (40); A tie rod (2) that is inserted in the seat (40) through one of its ends (2') presenting a slotting (10) that runs longitudinally in the direction of the length of the tie rod (2); The seat (40) being delimited superiorly by a superior surface (5') and inferiorly by an inferior surface (5''), both surfaces (5', 5'') further presenting a slotting (6', 6" ); A vertical pivot (4) passing through the slottings (6', 6'') of the superior (5') and the inferior surface (5") and the slotting (10) of the end (2') of the tie rod and that connects rotatably, around its axis, the tie rod (2) to the coupling element (3).

Description

TITLE

COUPLING ASSEMBLY FOR OPERATING CONTROL AND MOVEMENT OF THE BLADES OF A SWITCH POINT

Technical field

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

In particular, the invention refers to an innovative coupling assembly that handles the control and movement of the blades. 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 it 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 or stock rail which forms the correct layout. The term "blade" means in technical jargon a track of a pre-determined length and 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) are mobile through a specific control and manoeuvre apparatus that terminates with two tie rods coupled each one to a blade. The translation of the tie rods, thanks to a specific apparatus, causes a translation motion of the right and left blades, thus moving the switch point from right to left or vice-versa.

Generally, at the tip of the blade an apparatus is placed, as said, which has the function both of manoeuvre and of control.

Nevertheless, the length of the blades of a switch point can be significant. In this regard, in order to control and move correctly the blades of the switch point for all its length, it is necessary to arrange, at pre- determined intervals of length, intermediate control and manoeuvre apparatus that assist the head apparatus, allowing the correct movement of the blades, increasing the reliability, availability and safety of the entire switch point system.

Such an apparatus is structurally similar to that of head and it is also basically constituted by a pair of tie rods that are connected to the right and left blade through the coupling assembly terminating with a metal leg .

Figure 2A shows a coupling system of the background art that serves to actually connect the tie rods to the blade. The figure shows a single coupling assembly since the second one, which is the one that couples with the other opposed blade, is absolutely specular. The figure in question shows a component (Z) of the coupling assembly, called leg in the technical jargon, which, through bolting, connects rigidly to its blade through a flat connection face. The leg is then moved through a coupling hook (G) , 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, 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 transmitting the translation to the leg (Z) . In this way, the blade is moved to come close to or move apart from its stock rail.

Such a solution of the coupling assembly of the background art, however, presents different technical inconveniences, which will be mentioned right below.

Above all, the first problem that can be found is that the traditional assembly described is particularly subject to 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 between the different components subject to the working loads can arrive to plastic deform and to weld among them, causing the subsequent detachment of parts of the weaker material under relative movement imposed by the manoeuvering device itself. The progressive reduction of resistant section leads inevitably to the breakage of the eroded component. The system described in figure l^'A is particularly subject to fretting since it is not only not optimized through the appropriate choice of idoneous material but also because it structurally does 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 solution of figure 2A has such a structural shape that the residues (like also the eventual dirt present in the operating environment blown in between the components with 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 hook (G) - pivot (P) coupling does not allow an expulsion by gravity of the impurities that are formed in the area of contact between the parts, the whole causing fretting.

Another technical inconvenience concerns the fact that the solution described of the background art fails to compensate in an efficient way excessive . size variations due to thermal effects and to construction tolerances. For example, always with reference to figure 2A, in case of thermal expansions that cause irregular distortions, for example inflexion of the blades, the connection between hook and pivot initiates to suffer strong tensions. In particular, the hook ( G ) , in the case of inflexion of the blade, opposes to said inflexion acting against the pivot. Not only does all this worsen fretting by local increase of the pressures, but it also triggers additional tensions that can bring to breakages by fatigue.

The problem of the limited degrees of freedom of the current solutions is clear also in the case in which to the lifting of the track, following a substitution of the normal support cushions with roller cushions (increase in the positioning height of 4mm) , the errors of holing and alignment of the components are added during all the mounting and holing phase of the switch point. If such misalignments cannot be compensated by the degrees of freedom allowed by the coupling system, then tensional states are produced that can accelerate much the reaching of critical conditions, such as the breakage of the mechanical components.

Basically, the degrees of freedom of the coupling assembly of the Prior Art described are totally inadequate to cover the several variants related to the working environment, . the whole not just amplifying the fretting phenomenon but also causing additional tensions that contribute to the breakage of the end couplers themselves.

A further system that is well known in the state of the art is represented by American document US1463984, which describes the preamble of claim 1.

Also in this case such a system, nevertheless, does not present an adequate number of degrees of freedom suitable for compensating the several cases in which there can be size variations, as mentioned above.

The whole obviously introduces tensional states that can cause breakage very rapidly.

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 for the control and manoeuvre apparatus 1 structured in such a way as to reduce the fretting phenomenon, allowing the washing, for example, and contextually to 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 for an apparatus (1) for controlling and manoeuvering the blades (A, B) of a switch point, in accordance with claim 1.

- Such an assembly ( 2 , 3) comprises:

- A coupling element (3) to the blade (A, B) comprising a surface (3') of connection to the blade and, on the opposite part, a seat (40) ;

- A tie rod ( 2 ) that is inserted in the seat (40) through one of its ends (2') presenting a slotting (10) that runs longitudinally in the direction of the length of the tie rod (2) ;

- The seat (40) being delimited superiorly by a superior surface (5') and interiorly by an inferior surface (5'') .

In accordance with the invention, the two surfaces (5', 5'') both further present a slotting (6', 6' ' ) ·

Moreover, a vertical pivot (4) is foreseen, passing through the slottings (β', 6'') of the superior (5' ) and inferior surfaces (5'') and the slotting (10) of the end (2' ) of the tie rod and that connects rotatably, around its axis, the tie rod (2) to the coupling element (3) .

This type of connection allows to give a solution to the technical problem of fretting since this embodiment, with such an arrangement of the slots, allows a "washing" and therefore the exit of the residues. Moreover, such a solution allows to compensate and reduce to the minimum tensional states due to movements of the components and thermal expansions because on the whole the assembly is structured so as to have many more degrees of freedom.

Advantageously, the pivot (4) has such a size as to result sliding along the slottings (6', 6'') and at the same time along the slotting (10) of the tie rod.

This solution allows to compensate the thermal expansions and the effect of covering of the apparatus.

Advantageously, an element (11) of plastic material is further foreseen, provided with a passing hole for the passage of the pivot (4) and arranged slidingly along the slot (10) of the tie rod (2) .

Advantageously, the element has- the shape of a nut and is preferably of polyamide.

The shape with flat faces of the nut eliminates the relative rotation between nut and sliding seat of the tie rod .

Advantageously, the pivot (4) is rotatable with respect to the element (11).

The metal-plastic coupling between pivot and nut during the relative rotation further reduces the fretting phenomenon .

Advantageously, the superior surface (5' ) and the inferior surface (5' ' ) are horizontal and spaced between them of such a quantity that the end (2' ) of the tie rod, when inserted in the seat (40), has a pre-determined vertical gap in the direction of the axis of the pivot (4) .

The vertical gap allows a compensation in case of variation of height of the blade.

Advantageously, the end (2' ) of the tie rod is milled superiorly and interiorly.

This solution facilitates the insertion of the tie rod in the seat.

Advantageously, the two slots (6', 6'') develop according to an orthogonal direction with respect to the direction of development of the slot (10) .

It is also described here a control and manoeuvre apparatus comprising an assembly as described.

Last, it is also here described a switch point comprising a control and manoeuvre apparatus.

Brief description of drawings

Further features and advantages of the present coupling 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 1A and 2A describe the Prior Art;

- figure 1 shows an axonometric view of the overall assembly 1 of manoeuvre and control of the movement of the blades of the switch point;

- figure 2 shows in an axonometric view in detail the tie rod - right or left leg coupling assembly;

- figure 3 is an exploded view of the components of figure 2;

- figure 4 , always in an axonometric view, shows in detail just the leg provided with pivot and nut;

- figure 5 shows in a lateral view always the leg-tie rod assembly with the leg connected to its blade;

- figure 6 and figure 7 show a top view of the entire control and manoeuvre apparatus;

- figure 8 shows in detail just the nut.

Description of some preferred embodiments

Figure 1 describes the control and manoeuvre apparatus 1 comprising the coupling assembly in accordance with the invention. In particular, the right tie rod and in the same manner the left tie rod 1 are highlighted, both connected to the respective leg 3. The leg connects through ordinary bolts to the own respective blade.

Always figure 1 shows, covered by a carter 300, the hydraulic apparatus that allows the movement of the tie rods through the input of oil in pressure. Said apparatus is well known in the state of the art and is not the object of the invention, and for this reason it will not be described with further detail here.

As described in the axonometric figure 1, the apparatus 1 comprises the coupling assembly realized from Figure 2 shows in detail just one of said two couplings that are the right and left tie rod-leg coupling identical between them, the object of the present invention. In particular, the leg 3^' is highlighted, the tie rod 2 and the connection thereof that takes place through a pivot 4 mounted rotatably with respect to both the components (2, 3) . The exploded view of figure 3 shows better in detail all the components.

With reference to the single leg 3, it foresees a flat vertical surface 3' for the connection to the blade. To that aim, said surface 3' is holed for the passage of the connection bolts. Figure 4, for clarity purposes, shows precisely the passage of the bolts and an assembly of connection plates.

Always as shown both in figure 3 and in figure 4, the leg, on the opposite part to the surface 3' , foresees a seat 40 of insertion and connection to the tie rod. Such a seat is delimited through two overlapped parallel planes (5' , 5' ' ) and spaced between them appropriately. Both the superior plane 5' and the inferior plane 5' ' present a passage slot (6', 6'') for the insertion of the pivot 4 highlighted in figure 3.

The slot is selected of an appropriate size (length and width) in such a way that its length results greater than the pivot 4 as far as the diameter is concerned. This helps to create a sliding seat of the pivot 4 and therefore a relative translational motion along the direction of the. slot between tie rod and leg.

This type of connection has a first technical advantage which is that of compensating easily the thermal expansions of the blades, on the basis of the positioning of the apparatus 1 along the switch point, and therefore local translations of the legs through the blades, with respect to the tie rods.

Going on with the structural description of the invention, the tie rod 2 of figure 2 foresees, in correspondence of its end of connection in the seat 4 of the leg, a further slot 10 obtained in the longitudinal direction of the tie rod (therefore orthogonal to the slots 6' and 6''). In particular, the end 2' is milled in such a way as to have flat surfaces suitable for the insertion in the seat 4.

The connection between the tie rod 2 and the leg 3 takes place, as already said, through the pivot 4 that is inserted in the slots (6', 6'', 10), as highlighted in the exploded view of figure 3 and in the view of figure 2.

The technical functionality of the slot 10 is important to optimize the functioning of the assembly and will be described below.

Always with reference to figure 3, a nut 11 is then foreseen, preferably in a soft material such as plastic (for example polyamide, under the identification acronym PA66) and of such a size as to be inserted slidingly in the slot 10 of the tie rod (see for example the lateral view of figure 5 or always the exploded view of figure 3) . The nut, of a more or less cubic shape, is therefore holed axially to allow the insertion of the leg of the pivot 4 (see figure 4). In particular, the cylindrical coupling between pivot and nut is such as to permit relative rotations between the same components during the movement of the blades.

In particular, the leg is rotatable with respect to the tie rod around the axis of the pivot 4.

This solution has a very significant technical advantage since it allows to compensate distortions that cause a relative rotation between leg and tie rod. For example, the top view of figure 6 and 7, although in a minimum way, highlights a certain misalignment that there exists between leg and right tie rod with respect to the left coupling due to the rotation of the blade, on the plane of the view, following the manoeuvre made.

As then shown in the lateral view of figure 5, preferably the height of the seat 4 of the coupling leg is greater with respect to the height of the milled end 2' of -lithe tie rod. In this manner, as it can be understood from figure 5, there exists a vertical gap that allows to compensate the height variations of the leg in case for example of change of the dragging support bearing with those with rollers. Moreover, it allows to compensate the alignment errors due to the holing of the blade for the mounting of the leg itself.

Such a solution allows to compensate well the variation of height since the leg can lift itself along the pivot inside the seat 4, therefore keeping a good coplanarity between leg and tie rod and avoiding the appearance of tension phenomena.

Going back to figure 3, the remaining structural components are constituted by two spacing rings and by a pair of stop pliers that serve to maintain in position the pivot once it is mounted.

The solution described (see for example figure 4) has the further big advantage of reducing to the minimum the fretting phenomenon for the following reasons.

Above all, the selection of the nut of plastic significantly reduces the phenomenon of micro-weldings and therefore fretting. In addition, this solution, unlike the state of the art described, allows the washing since all the eventual impurities present in the contact areas between pivot and slots (6', 6'') fall off by gravity. In the same manner, any eventual residue between the contact areas of the nut and of the slot 10 falls off by gravity.

The technical advantage of a slotting 10 obtained on the tie rod is instead the following.

With reference to figure 7 a section of switch point is shown on which the apparatus 1 is installed contemplating the coupling assembly that is the object of the present invention. The figure shows the pipe through which the sending of oil in pressure to activate the tie rods takes place. The mechanism of movement of the tie rods, well known in the state of the art, is such that the two blades move contemporarily just for a short translation section. In particular, with reference to figure 7 and in the hypothesis that the blade A and the blade B move from left to right (see direction of the arrow), what happens is that initially just the blade A translates to the right, while the blade B remains still. This is because the tip apparatus makes a pre-fixed safety "covering" stroke. Basically, the mechanism is such as to result idle for a short section and therefore the blade B remains still. Once the covering by the tip apparatus is eliminated, both the blades A, B will move integrally until the blade A arrives to the stop. The same thing happens on the blade A in the inverse return motion.

The function of the slot 10 is now clear. Figure 7 highlights the pivot 4 on the part of the blade A and that is found in contact with the back stop of the slot 10 in such a way as to move the leg when the tie rod pushes in the direction of the arrow. The pivot of the opposite leg (relative to the blade B) is instead found always inside the slot but on the opposite part (see slot 10' in transparency) . When the movement from left to right takes place (see always direction of the arrow) the slot permits a left stroke of the tie rod but avoiding that the tie rod drags the left leg for the equivalent length of slot that is available. In this way, during the safety covering of the tip apparatus at still blade, the left tie rod has a free stroke section equivalent to the length of the slot, or better, to the residue length of the slot since a part is occupied by the diameter of the pivot 4. In this way, the elimination of the covering at still blade of the head apparatus takes place without impediments or resistances induced by the apparatus 1 with consequent reductions of the maneuvering times of the blades and of the forces involved .

Claims

CLAI S

1. An assembly (2, 3) for a control and manoeuvre apparatus (1) of the blades (A, B) of a switch point and comprising:

- A coupling element (3) to the blade (A, B) comprising a surface (3') of connection to the blade and, on the opposite part, a seat (40);

- A tie rod (2) that is inserted in the seat (40) through one of its ends (2' ) presenting a slotting (10) that runs longitudinally in the direction of length of the tie rod (2) ;

- The seat (40) being delimited superiorly by a superior surface (5') and inferiorly by an inferior surface (5' ' ) ;

- Characterized in that both surfaces (5' , 5' ' ) further present a slotting (β', 6'');

- And wherein a vertical pivot (4) is further foreseen passing through the slottings (β', 6'') of the superior surface (5') and the inferior surface (5") and the slotting (10) of the end (2' ) of the tie rod and that connects rotatably, around its axis, the tie rod (2) to the coupling element (3) .

2. An assembly (2, 3), according to claim 1, wherein the pivot (4) is of such a size as to result sliding along the slottings (β', 6'') and contextually along the slotting (10) of the tie rod.

3. An assembly (2, 3), according to claim 1 or 2, wherein an element (11) of plastic material is further foreseen, provided with a passing hole for the passage of the pivot (4) and arranged slidingly along the slot (10) of the tie rod (2) .

4. An assembly (2, 3), according to claim 3, wherein said element has the shape of a nut and is preferably of polyamide.

5. An assembly (2, 3), according to one or more of the preceding claims, wherein the pivot (4) is rotatable with respect to the element (11) .

6. An assembly (2, 3), according to one or more of the preceding claims, wherein the superior surface (5' ) and the inferior surface (5'') are horizontal and spaced between them by such a distance that the end (2') of the tie rod, when inserted in the seat (40), has a pre-determined vertical gap in the direction of the axis of the pivot (4) .

7. An assembly (2, 3), according to one or more of the preceding claims, wherein the end (2') of the tie rod is milled superiorly and interiorly.

8. An assembly (2, 3), according to one or more of the preceding claims, wherein the two slottings (β', 6' ' ) develop according to a direction orthogonal to the direction of development of the slot (10).

9. A control and manoeuvre apparatus comprising an assembly, as per one or more of the preceding claims .

10. A switch point comprising an apparatus, as per claim