EP2882627A2

EP2882627A2 - A friction device for interrupting the approaching motion between blade and stock rail in case of an obstacle that impedes the normal manoeuvre

Info

Publication number: EP2882627A2
Application number: EP13765523.9A
Authority: EP
Inventors: Felice GRANDE
Original assignee: Wegh Group SpA
Current assignee: Wegh Group SpA
Priority date: 2012-08-07
Filing date: 2013-08-05
Publication date: 2015-06-17
Anticipated expiration: 2033-08-05
Also published as: ITFI20120162A1; EP2882627B1; WO2014024117A2; WO2014024117A3

Abstract

The present invention concerns an assembly of manoeuvre (1) for a switch point comprising: - A circuit (4', 4", 14', 14", 14"') for the circulation of a fluid; - Means (2) for sending the fluid in pressure along said circuit (4', 4", 14', 14", 14"'); - An actuator (20) for commanding the manoeuvre and connected to the circuit in such a way as to translate in correspondence of the sending of the fluid in pressure; - And wherein a friction device (100) is further foreseen interposed in the circuit (4', 4", 14', 14", 14'"), said friction device (100) comprising at least a pressure valve (110, 115) arranged in such a way as to intercept the circulating fluid and measure the pressure value thereof in such a way that, in correspondence of the excess of a pre- established threshold pressure value, a block signal is generated.

Description

TITLE

A FRICTION DEVICE FOR INTERRUPTING THE APPROACHING MOTION BETWEEN BLADE AND STOCK RAIL IN CASE OF AN OBSTACLE THAT IMPEDES THE NORMAL MANOEUVRE

Technical field

The technical field of the present invention is relative to the railway devices that manage the movement of the tracks of the switch points.

In particular, the invention refers to an innovative friction device suitable for managing the movement of the switch points in case of impediment to the normal manoeuvre in differential mode and on the basis of the approaching direction, as in the presence of an interposed obstacle between blade and edge rail or in the presence of strong friction.

Background art

Along the rail tracks turnout areas have long been known, which allow the train to vary its route from a branch to another of the track. To that aim, the so-called switch pointa have been foreseen, as for example shown in figure 1A of the prior art.

The switch point allows the transit of the trains from the branch of the correct layout to the deviated branch and vice-versa. The transit on one or on another branch takes place thanks to the particular structure of the switches which, always as shown in figure 1A, are characterized by 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 track. 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 appropriate manoeuvre apparatus with the aim of managing the layout of the train,

Just for clarity purposes figure 2Ά highlights a switch point with the two blades 101 and 102, the first one of which in close position and the second one in open position. Always the same figure shows the transit of a train, represented just with the axle and running gears, which engages the switch point by the heel and finding it in a wrong position in fact generates the forced translation of the two blades from left to right, by means of the so-called phenomena of the splitting the points of the switch point.

The "splitting the points" phenomena (in technical jargon) takes place when the train, engaging the blade heel switch, finds it in false position with respect to its driving direction. Basically, with reference to figure 2A-bis, what happens is that the direction of the distance covered is such that the left wheel goes forward along the gap formed by the blade 101 that progressively closes on itself, coming close to its edge rail, while the other wheel travels exclusively on the blade 102 which however progressively moves apart from its edge rail. Since the axis of distance between the two wheels of the train is fixed, this progressive reduction of the distance between the two blades (101, 102) determines during the advancement of the wheels the birth of a force called splitting the points force (see direction of the arrow of figure 2A) that in fact causes, in this example, a forced translation of the two blades from left to right. In the background art, the electromechanical devices that manage the movement of the blades of the switch point can allow or not the manoeuvre of splitting the points depending on the fact that they can be respectively split or not and these last ones in a permanent way or electrically controlled.

Figure 3A, always of the Prior Art, shows a widespread critical situation and represented by the presence of an obstacle, for example a stone, interposed between blade and stock rail (also called edge rail in the present description) . In this case the normal movement of the switch point is impeded, since the obstacle inhibits the approaching of the blade and its stock rail, leaving the switch point in a false position that would cause the derailment or deviation of the train. It is therefore essential that this situation is immediately informed to the train with an indication of red street light, in addition to switching off the motorization that controls the movement of the blade towards the stock rail, in such a way as to avoid breakdowns thereof, which are the cause of high maintenance and replacement costs.

In the background art, the elastic component that manages splitting the points and friction is the spring element F, highlighted in the succession of figures from 4A to 8A. In particular, figure 4A shows a superior slide A with the manoeuvre point rods that connect with the blades to move them to the right or to the left. The superior slide A foresees a pivot or needle B upstream and downstream of an internal seat where the spring F is lodged interposed between two C elements, integral to the spring. The elements C, in technical jargon called "biscuit-holders", are provided with translation motion with relation to the seat obtained in the slide A. Below an inferior slide G is foreseen, provided with translation motion with relation to the superior slide A, which brings integral to it two further opposed pivots or needles H. Inside the spring a shock absorber device is generally added.

As already said, this device, called "mechanical unbinding device" in the technical jargon, manages both the splitting the points and the friction.

The normal right-left or left-right closing movement is operated by connecting the inferior slide G to a sliding block fixed to a worm screw which, in turn, is made to rotate by the engine. At high speed a connection to an actuator is instead used.

In the case of worm screws, the engine rotates the worm screw causing the translation of the sliding block in a direction or in the opposite one (not represented in a figure for simplicity purposes) , which in turn causes the translation of the slide G, being connected to it. The biscuits E, in the embodiment of figure 4A, normally annul the motion relative to the translation between the slide A and G, binding them reciprocally through the pivots B and H. During the normal functioning of the machine, what will happen is an integral dragging of the superior slide A thanks to the dragging of the inferior slide G through the pivots B and H.

In the case of friction of the machine, caused by the presence of an obstacle between blade and stock rail (figure 5A) , the mentioned device allows the unbinding of the two slides A and G in such a way that the last one can reach the stop to switch off the engine and send the stop signal to the train (red street light) . In fact, the slide A stops due to the obstacle and the rotation of the worm screw moves the inferior slide G by means of the driving force Fr2 (figure 5A) , dragging the biscuit-holder C, by means of the biscuit E, and therefore generating the compression of the spring F. As shown in the subsequent figure 6A, the relative translation motion mentioned terminates when the biscuit has enough space to rotate, thanks to an adequate compression of the spring. Therefore, once the rotation has taken place, the mechanical unhooking of the slide G ii obtained with respect to the slide A.

The same device of said figures manages also the splitting the points, as shown in the succession of figure 7A and 8A. It is reminded that in the case of splitting the points the moving force of the blades is furnished not by the movement engine, which in this case is switched off, but by the inertia itself of the train that transits, as in the example shown in figure 2A-bis.

In this case, the superior slide A with respect to the inferior one G will be responsible for the translation, being the inferior one kept in position by the switched off engine, and therefore blocked. The passage of the train therefore creates the force on the blade (Fol) that brings the progressive compression of the spring F with consequent unbinding of the biscuit, through translation and subsequent rotation with respect to its pivot. Once the rotation of the biscuit has taken place, the mechanical unbinding of the superior slide A is obtained, with respect to the inferior slide G, in such a way that eventually a stop signal to the train (red street light) can reach at a stop.

Having explained this, the technical problem is that two phenomena deeply different between them, that is friction and splitting the points, are both managed by the same component, that is the spring F.

The safety norms however impose different setting values of the spring in case of friction and in case of splitting the points. In particular, in case of friction, the norms foresee an indicative setting value of the spring of about 550 [daN] ( Deca-Newton) , while in case of splitting the points the value is about the double, that is about 1.000 [daN] . It Is clear that it is very difficult, if not even impossible, to realize a single component (in this case the spring F) that contextually foresees two settings so much different between them. It is therefore necessary to arrive at a compromise setting with the risk of not meeting normative requirements and, above all, to the detriment of safety.

A particular type of switch point for high speed is for example described in the publication EP0480303. The publication describes the use of an assembly of actuators placed along the line of the switch point and structured in such a way as to keep solid and fixed the position occupied by the switch point itself. In this way, dangerous involuntary movements of the blades are avoided, to the advantage of the safety and of the duration of the actuators themselves. The patent application describes then a control unit for such actuators. Such a control unit foresees an engine that activates a pump which sends oil in pressure in a circuit that obviously converges to the actuators. The pump withdraws the oil from a tank and further safety tanks are foreseen to avoid and compensate pressure drops. In the circuit, downstream of the pump but before arriving to the actuators, the following are arranged in succession: a high pressure measuring valve, a low pressure measuring valve, a motorized valve that controls the closing of the oil delivery to the actuators. The two measuring valves detect a measure of pressure of the circulating oil and send an electrical signal that controls the activation of the motorized valve when the measure detected results inferior to the value to which the low pressure valve is set, or superior to the value to which the high pressure valve is set. In fact, there is a free flow of oil between said two valvee towards the actuators up to when one of these two valves does not send an electrical signal to the motorized valve that intervenes with a direct interruption on the circuit towards the actuators. In this way, for example, if there is an obstacle in the switch point that causes the rising of the pressure of the circulating oil, then a block of the activation of the actuators takes place, through the motorized valve that closes the feeding of oil. The motorized valve foresees a rotatable axis that rotates a shutter between an open position and a close position of the circuit. Contextually, such a valve sends a block signal to the engine of the pump.

This system has, however, a series of technical inconveniences.

The predominant issue is that the closing of the motorized valve takes place through a first electrical signal sent from the over or under pressure valve towards the motorized valve itself. Subsequently to the closing of the circuit, after the actuation of such a motorized valve, it is set in a position of sending of a further electrical signal that switches off the feeding engine of the pump. Basically, there are two electrical signals with a higher risk of malfunctioning in case one of these signals is accidentally interrupted.

Moreover, the two pressure measuring valves limit themselves just to measure the pressure and anyway allow the free flow towards the motorized valve also when the values detected are beyond the threshold limits to which they are set. Once those limits are exceeded, if a hypothetical interruption of electrical signal between the measuring valves and the motorized valve took place, not only the main engine of the pump would continue to rotate but, above all, no system would intervene to interrupt the feeding . Disclosure of invention

It is therefore the aim of the present invention to provide a friction device for a switch point that solves this and other technical inconveniences.

In particular, the need is felt in a switch point device to have devices of management of the splitting the points and of the friction that are independent between them, with the aim of thus responding faithfully to what is established by the norms in force.

The need is also felt in a switch point device to have a specific device of management of the friction that has a minor risk breakdown, in particular eliminating a redundant electrical connection and taking advantage physically of the action of over-pressure itself detected and indicative of the obstacle.

These and other aims are therefore reached with the present assembly of manoeuvre (1) for a switch point, in accordance with claim 1.

The assembly of manoeuvre (1) comprises:

- A circuit (4', 4", 14', 14'', 14'") for the circulation of a fluid;

Means (2) for sending the fluid in pressure along said circuit (4', 4'', 14', 14", 14"');

An actuator (20) for commanding the manoeuvre and connected to the circuit in such a way as to translate in correspondence of the sending of the fluid in pressure.

A friction device (100) is further foreseen inserted in the circuit (4', 4", 14', 14", 14"') and suitable for detecting an obstacle that impedes the manoeuvre, said friction device (100) comprising:

A path (160, 161, 162) for receiving the fluid circulating in the circuit;

At least one pressure valve (110, 115) arranged in such a way aa to intercept the fluid entering in the path (160, 161, 162) and detect the pressure value thereof.

According to the invention, the pressure valve is further configured in such a way as to obstruct said path (160, 161, 162) for pressure values below a pre- established threshold value and get open and allow the flow once reached or exceeded the pre-established threshold value.

Unlike the background art, the valve interrupts the path in case of under-pressure and opens the path in case of over-pressure, indicative of the obstacle.

Moreover, means (125, 120, 200) are further foreseen to generate a signal, preferably an electrical signal. Said means (125, 120, 200) are arranged in the friction device in fluid communication with said path (160, 161, 162) in such a position as to intercept the circulating fluid following the opening of the pressure valve. Such means are further configured to be activated through the pressure of the fluid with which they enter into contact following the opening of the valve.

Such a solution solves easily said technical problems since a redundant electrical signal is eliminated (electrical signal of the valves of over and under pressure of the background art), significantly lowering the risk and the probability of breakdown. In case just of over-pressure, it is the fluid itself now that activates mechanically the means that generate a single block signal, that is the electrical block signal of the engine or of the pump. The electrical signal is therefore eliminated, which instead served in the background art to activate the closure of the motorized valve and which, in turn, sent a block signal to the engine. Moreover, the solution as claimed does not require a direct closure of the feeding but, through the friction device, there is a block as a consequence of a signal. This makes that the -losingle friction device could be inserted also in a pre- existent circuit and therefore just to serve as "sentinel" without the need for changing completely the entire structure.

The appropriate insertion of the friction device in the circuit, in fact a pressure measuring valve device, allows to detect the circulating pressure. If a pressure value that is beyond the pre-established threshold is detected, this indicates the presence of an obstacle that Impedes the normal closure of the blade towards its stock rail. The generation of the electrical signal can then be foreseen, which will command, for example, the block of the pump and/or the generation of an alarm signal (for example red street light).

This solution, in a simple and economical manner, allows to unbind the manoeuvre of splitting the points, managed by the spring, from the manoeuvre of friction. The friction is now managed through a detection of circulating pressure, which is indicative of an obstacle that impedes the normal closure of the blade close to its stock rail.

Advantageously, the friction device (100) comprises a first pressure valve (110) and a second pressure valve (115).

Advantageously, the friction device (100) comprises an inlet (14'', 14'' ') with a path (160, 161) that intercepts the valve/s (110, 115) .

Advantageously, the friction device (100) comprises a first inlet (14''') that intercepts the first valve (110) and a second inlet (14''), independent from the first inlet, and that intercepts the second valve (115).

Advantageously, said means (125, 120, 200) to generate a signal comprise a stem (125) arranged slidingly in a sliding seat, in such a way that, once the threshold value of the pressure measured has been exceeded, the valve opens allowing the inlet of the fluid in the sliding seat and causing the translation of the stem, said translation of the stem generating a signal through a block assembly

(120, 200) with which it is cooperating.

Advantageously, the sliding seat is in fluid communication with the pressure valves downstream of the pressure valve on the- opposite part to the inlet

(14' ' ,14' ' ' ) .

Advantageously, said block assembly (120, 200) comprises an arm (120) and an assembly of electric knives (200), the arm (120) being hinged to the friction device (100) in such a way as to rotate of a pre-determined quantity in correspondence of a translation of said stem (125) to which it results connected, said arm (120) having an end cooperating with the assembly of electric knives (200) arranged in such a way that said assembly (200) generates a pre-determined electrical signal in correspondence of said rotation of the arm.

Advantageously, said assembly of electric knives (200) comprises a rotatable drum (210) provided with one or more blades (220), the drum comprising a toothing (250) which engages with a corresponding toothing of the arm (120) in such a way that the rotation of the arm (120) through said toothing is transmitted to the drum that brings the blades (220) in a pre-determined position for the generation of a specific electrical signal.

It is also here described the single friction device which, for example, would be easily insertable and adaptable to any pre-existent control system.

Such a friction device (100), for detecting an obstacle that impedes the manoeuvre in an assembly of manoeuvre of a switch point, is suitable for resulting connectable in a circuit (4', 4'', 14', 14'', 14''') of said assembly of manoeuvre and comprises: A path (160, 161, 162) for receiving the fluid circulating in the circuit;

At least one pressure valve (110, 115) arranged in such a way as to intercept the fluid coming in in the path (160, 161, 162) and detecting the pressure value thereof.

According to the invention, said pressure valve is further configured in such a way as to obstruct said path (160, 161, 162) for pressure values below a pre- established threshold value and open to allow the flow for pressure values above said threshold value;

And wherein means (125, 120, 200) are further foreseen to generate a signal, preferably an electrical signal;

Said means (125, 120, 200) being arranged in the friction device in fluid communication with said path (160, 161, 162) in such a position as to intercept the circulating fluid following the opening of the pressure valve, said means being further configured to be activated through the pressure of the fluid with which they enter into contact..

In this way, by interposing the friction device 100 in a control circuit that moves a dragging actuator of the point rods, the circulating pressure can be detected (indicative of the eventual presence of an obstacle) and command, for example, the switching off of the pump that feeds the oil in pressure, taking advantage of the electrical signal emitted.

In particular, advantageously, the following are foreseen:

A first inlet for a fluid in pressure and a first valve (110) in communication with the first inlet through a first path for the fluid;

- A second inlet for the fluid in pressure and a second valve (115) in communication with the second inlet through a second path for the fluid.

In this way, two differently calibrated valves can be used, each one that depends on a branch of the circuit.

Advantageously, said means (125, 120, 200) comprise a stem (125) arranged slidingly in a sliding seat in such a way that once said threshold pressure value has been reached, the corresponding valve opens, allowing the inlet of the fluid in the sliding Beat and causing the translation of the stem, said translation of the stem generating said signal through a block assembly (120, 200) with which it is cooperating.

Advantageously, said block assembly (120, 200) comprises an arm (120) and an assembly of electric knives (200) , the arm (120) being hinged to the friction device (100) in such a way as to rotate of a pre-determined quantity in correspondence of a translation of said stem (125) to which it results connected, said arm (120) having an end cooperating with the assembly of electric knives (200) arranged in such a way that said assembly (200) generates a pre-determined electrical signal in correspondence of said rotation of the arm.

Advantageously, said assembly of electric knives (200) comprises a rotatable drum (210) provided with one or more blades (220) , the drum comprising a toothing (250) which engages with a corresponding toothing of the arm (120) in such a way that the rotation of the arm (120) through said toothing is transmitted to the drum that brings the blades (220) in a pre-determined position for the generation of a specific electrical signal.

Advantageously, the two valves have, each one, a different threshold pressure value.

Brief description of drawings

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

figures from 1A to 8A describe a switch point, the splitting the points and the friction and the device that currently manages both splitting the points and friction;

- figures from 1 to 3 show in an axonometric view the friction device in accordance with the invention;

figure 4 shows a detail of the gear pump used to send the oil in pressure in the circuit;

- figure 5 shows an overall view with the slide A moved through the actuator 20 to operate the manoeuvre of the switch point;

- figure 6 shows a section of the actuator 20;

- figure 7 shows a detail of circuit that connects to the actuator 20;

- figures from 8 to 16 show various views of the friction device 100, subject of the present invention, which controls the value of the pressure circulating in the oleo-dynamic circuit of the machine;

figure 17 shows an enlarged detail, always relative to the slide A;

- figure 18 shows an overall view that highlights the placement of said friction device, that is in an appropriate box installed in a metal sleeper in substitution of the relative sleeper in pre-stressed concrete of the switch point.

Description of some preferred embodiments

Figures from 1 to 3 show prospective views of an assembly 1 of manoeuvre that manages the movement of the blades and comprising the friction device 100 in accordance with the invention, connected to the hydraulic circuit of the manoeuvre.

In particular, as shown for example in figure 3, the assembly 1 foresees an apparatus 2 for feeding a fluid in pressure, for example oil. The apparatus, as shown in the detail of figure 4, is of the oleo-dynamic type and therefore comprises a gear pump which sends the oil in pressure to a circulating circuit that will be better explained below. Figure 4 shows in detail the gear pump and that comprises, as it is well known in the state of the art, a rotary engine 10 which, by means of a transmission belt 11, conducts in rotation a pulley 12. The pulley activates a delivery mechanism in pressure of the oil towards the circuit thhrough a delivery conduit. Obviously, for the aims pre-established by the present invention, any type of gear pump can be used and it is clear for the expert of the field that any apparatus capable of sending oil in pressure in the circuit can anyway be used, without for this moving apart from the present invention.

Figure 5 shows better in detail the rest of said assembly 1.

In particular, figure 5 shows the superior slide A of the background art where inside of it the spring is placed. The spring, not shown for simplicity purposes, will have just the mechanical function of splitting the points. The superior slide A therefore foresees the tie- rods that connect normally to the blades for the movement during the splitting of the points or during a standard switch. In case of splitting of the points the internal spring will intervene, as described in the background art. An underlying actuator 20, described right below, commands the normal translation of the tie-rods belonging to the slide A in a normal manoeuvre.

As precisely shown in figure 5, the superior slide A is bound to the assembly 1. In particular, .figure 3 shows an actuator 20 which, as shown in figure 2, is bound rigldly to a slide 21. The block takes place by means of a fork 22 inserted on the stem of the actuator.

The actuator 20 is further shown in detail in the section of figure 6. The actuator foresees an internal stem 25, called plunging stem 25, which is sliding in two cylinders (26', 26'') that define, each one, a chamber (27', 27'') of containment for the oil that arrives in pressure from the pump 2, Through connection fittings (30, 31), which, for clarity purposes, are shown also in figure 5, the oil, which arrives in pressure from the pump 2, has access to a chamber (for example the 27' or the 27''), thus obliging the stem 25 to the sliding on one part or on the other part with respect to the cylinders.

Always figure 6 shows two workings 33 in the shape of incisions which allow the hooking to the slide 21 through the fork 22, as also shown in figure 2.

Going on with the structural description of the invention, the circuit, which allows the circulation of the oil in pressure, is well highlighted in the axonometric view of- figure 3. The circuit comprises a first delivery branch (4', 4'') that foresees a first section 4' that joins with an end of the actuator (the end on the part of the chamber 27'' of figure 6) through a connection conduit 4''. In this way, when fluid in pressure is sent through the branch (4', 4''), the stem 25 moves from left to right, dragging as a consequence the slide 21 and the superior slide A integral to it along said direction.

Figure 7 shows in detail well the junction between the two sections 4' and 4'' that form said first branch.

Always with reference to figure 3, the circuit comprises also a second branch (14', 14'', 14'''), responsible for the movement of the stem in the direction opposite to the preceding one, that is from right to left. It is therefore foreseen a delivery section 14' that this time enters directly into the chamber 27' to exert said push on the stem from right to left (see also detail of figure 7) . With reference to the detail of figure 7, it can be seen how, contextually, part of the oil, which enters into the chamber 27' to push the stem, deviates on the branch 14' ' .

The branch 14'', as well highlighted in figure 3, gets closed on a friction device 100 for the control of the pressure, which then joins the chamber 27'' through the section 14' ' ' .

Figures from 8 to 16 describe in detail said friction device 100.

Figure 8 shows said friction device 100, which is in the shape of a metal block.

The friction device comprises two pressure control valves (110, 115) , which are of the open/close type on the basis of the pressure of fluid they detect. If the pressure value detected is below a certain threshold value, then they close the passage of the oil; otherwise, they open such a passage towards a system of generation of an alarm signal. Those types of valves can be, for example, of the spring type with pre-established pre- compression, such as the ones produced by Oleostar.

Figure 8 shows the connection 'couplings to the sections 14'' and 14''', that is two independent inlets of the fluid in the friction device 100. Always figure 8 shows the two pressure control valves, that is the valve 110 and the valve 115. Figure 8 further shows a movement element 120 in the shape of a folded arm with a dented end. The arm is rotatable of a pre-determined rotation arc thanks to the dragging of a guiding stem 125 to which it results bound.

Figure 9 shows the conduits internal to the device 100 that allow the entry of the oil in pressure inside said device in such a way that the valves 110 or 115 can detect a pre-determined value of pressure circulating in the first branch (4', A'') or in the second branch (14', 14' 14''') according to the case.

In particular, figure 9 shows how the movement element 120 foresees an arm 121, folded in an L shape, hinged to one of its ends 122 in such a way as to rotate of a pre-determined excursion around said fulcrum 122. The reciprocation of translation of the guiding stem 125 therefore causes a dragging in rotation relative to said element 120 around the fulcrum 122.

The detail of figure 10 shows a side of the entry of the oil in pressure (for example the side 14' ' or the side 14'''). The oil, entering from on© part, is obliged to ascend towards a valve (110 or 115 according to the entry from which the oil arrives), which measures the pressure of the oil. The ascent path is indicated in figure 10 with numbers 160 and 161. For example, in this example case of figure 10, the entering oil comes from the section 14''' of the circuit and ascends to the corresponding valve through the section 160 and the subsequent vertical section 161. The valve closes the path of access to the stem 125. When a pre-determined threshold pressure value, to which the selected valve has been set, is exceeded (for example the friction value established by the norms, corresponding to the 550 [daN] previously mentioned) , the valve opens, allowing the access to the oil in the conduit 162. The conduit 162 therefore brings to the sliding seat where the guiding stem 125 is lodged, causing its translation into the seat where it is slidingly placed. Figure 11, for example, shows the case in which said guiding stem 125 has been pushed to the stop all on the right part by means of the oil that runs over it, causing an equivalent rotation of the component 120 in clockwise sense. Therefore, with reference to figure 11, the fluid in entry from the part indicated with the direction of the arrow (therefore coming from either the first or the second branch of the circuit depending on how the connection was made), causes the opening of the relative valve and thus the translation of the stem 125 when a predetermined threshold pressure value has been exceeded. The same thing, in a specular way, takes place when the fluid enters from the opposite part. In this case, the stem rotates in the opposite direction, also rotating in the opposite direction the element 120 as a consequence.

The section of figure 12 shows in a very clear manner the sliding stem 125, with the entry holes for the oil in one or in the other chamber in order to make it translate from right to left or vice-versa, from left to right.

Figure 13 shows the same situation of figure 11 from the opposite part in which, precisely, the fluid enters and, in case a pre-established pressure value threshold is reached, causes the opening of the corresponding valve and therefore the entry in the chamber of the fluid that pushes the stem. 125.

Going on with the structural description of the invention, figure 15 shows an assembly of electric knives 200 installed on the friction device 100. The assembly 200 foresees a rotary drum 210 which has one or more blades 220 integral to it. On one part and on the other part with respect to the drum 210 electrical contacts 230 are arranged, which allow the entry of the blades 220, called "knives" in railway technical jargon. Depending on which blade enters in the contacts 230, a pre-determined electrical signal is generated, which can be used to command, in case of emergency, the switching off of the delivery engine of the oil in pressure and/or, for example, the switching on of an alarm signal for the train in transit.

The rotation of the drum 210 is obtained through a gear wheel 250 which is coupled with the dented wall of the element 120. Therefore, as it is clear from figure 15 or figure 16, depending on the translation of the stem 125 (from right to left or from left to right) a predetermined rotation of the drum 210 will be obtained thanks to the gear wheel 250 and element 120 coupling. All this allows to bring the knives 220 in two positions of electrical signal which can be managed without problems to command a motor block and/or an alarm signal or other.

Therefore, in normal operative conditions, the knives are in such a position as not to generate an electrical block signal. If a rotation thereof in one of the two extreme positions (on the basis of the entering side of the fluid in the friction device and of the pressure value) takes place, a corresponding signal is generated.

The detail of figure 17, last, shows how the superior slide A results connected to the slide 21 through an interposed plate 21' which is fixed to the slide 21.

As already described, the friction element 100 foresees two independent valves (110, 115) . A valve (the 110 with reference to figure 3) measures the pressure of the branch (4', 4'') through the section (14' '') that brings the oil in the device 100 to the valve 110, and the other one (the 115) that intercepts the path (14', 14'') to measure the pressure value thereof.

This solution is extremely advantageous since it allows to use two valves adjusted with different threshold values. In this way, when the assembly 100 of figure 3 is placed for example on an inclined section, this different adjustment of the valves allows to compensate the gravity force effect which is favorable in a direction and contrary in the opposite direction. In particular, the two blades will have to move in a direction, for example left to right, which can for example be in favor of the gravity force due to the steep pendency of the section. Consequently, in this example, when they will have to go from right to left, they will have to move against the gravity force. At equal movement speed, the oil in pressure shall have different values depending on which branch it goes to: either in the one that commands precisely the movement from left to right, or from right to left. This is because in the first case the translation is favored by the component of the weight force and in the opposite direction said component opposes. The use of two different valves allows an adjustment of the same with diversified threshold values, allowing a flexible management also on inclined planes.

Having structurally described the essential elements of the invention, we now pass on to a function description.

Taking as reference figure 2, the hydraulic pump 2 sends oil in pressure in such a way as to command the normal translation of the superior slide A through the movement of the actuator 20. In the case of a problem of friction the assembly 1 allows an automatic switching off of the engine 2 in the presence of an eventual obstacle between blade and stock rail. For example, with reference to figure 3, let's suppose we have to put the blades close from left to right. The engine 2 therefore sends oil in pressure along the path 4' and 4'', therefore causing a relative translation of the stem 25 from left to right. The Stem 25, through the slide 21, causes the rigid translation of the superior slide A that drags in movement the blades through the point rods. The oil that enters in the chamber 27'', and that causes the translation of the stem 25, flows also through the conduit 14''' towards the hydraulic friction device 100 which, through the valve 110 measures the pressure circulating in the branch (4', 4'') . In case a stone is interposed, which impedes the correct closure of the blades, in this case from left to right, the pressure detected from the valve 110 will increase progressively. Once a pre-set threshold has been exceeded, the valve opens. Figure 9 highlights how the path opened by the valve conducts the oil in pressure into the chamber of the stem, thus exerting a push that moves the stem 125 from left to right (see direction of arrow) with a consequent rotation of the element 120. Such a rotation (see for example figure 15) will cause an equivalent rotation of the gear wheel 250 and therefore of the axis 210 (drum 210) . The knives 220 will therefore be rotated in a specific position interposed between the contacts 230 to generate an electrical signal, for example an alarm signal and/or an engine stop signal. The increase in pressure is then measured in order to generate an electrical block signal when a pre-established threshold is exceeded. This avoids the breakage of the engine by overheating and, most important of all, the risk of deviation or derailment of the train caused by the passage on a badly positioned switch.

Obviously, the function principle is absolutely identical when, with reference to figure 3, the oil in pressure is sent through the conduit (14' , 14'') to the oleo-dynamic friction device 100. This is the case of translation of the actuator 20 from right to left. Also in this case, if there is an obstacle that impedes the correct manoeuvre, the friction device will intervene for the safety setting of the switch point system. in particular, once the threshold value of the pressure adjusted by the valve that is intercepted has been exceeded, the opening of the corresponding valve 115 and the translation of the stem 125 will take place.

The stem causes the rotation of the drum and the knives are brought in such a position with respect to the electrical contacts as to generate an electrical block signal.

Claims

1. An assembly of manoeuvre (1) for a switch point comprising :

- A circuit (4', 4", 14', 14", 14''') for the circulation of a fluid;

- Means (2) for sending the fluid in pressure along said circuit (4' , 4", 14', 14", 14'");

- An actuator (20) for commanding the manoeuvre and connected to the circuit in such a way as to translate in correspondence of the sending of the fluid in pressure;

And wherein a friction device (100) is further foreseen inserted in the circuit (4', 4", 14', 14", 14' ' ' ) and suitable for detecting an obstacle that impedes the manoeuvre, said friction device (100) comprising:

- A path (160, 161, 162) for receiving the fluid circulating in the circuit;

- At least one pressure valve (110, 115) arranged in such a way as to intercept the fluid entering in the path (160, 161, 162) and detect the pressure value thereof,

characterized in that said pressure valve is configured in such a way as to obstruct said path (160, 161, 162) for pressure values below a pre- established threshold value and get open and allow the flow once reached or exceeded the pre-established threshold value;

- And wherein means (125, 120, 200) are further foreseen to generate a signal, preferably an electrical signal;

Said means (125, 120, 200) being arranged in the friction device in fluid communication with said path (160, 161, 162) in such a position as to intercept the circulating fluid following the opening of the pressure valve, said means being further configured to be activated through the pressure of the fluid with which they enter into contact.

2. An assembly of manoeuvre (1), as per claim 1, wherein the friction device (100) comprises a first pressure valve (110) and a second pressure valve (115).

3. An assembly of manoeuvre (1), as per claim 1 or 2, wherein the friction device (100) comprises an inlet (14", 14"') with a path (160, 161) that intercepts the valve/s (110, 115).

4. An assembly of manoeuvre (1), as per one or more of the preceding claims, wherein the friction device (100) comprises a first inlet (14'") that intercepts the first valve (110) and a second inlet (14"), independent from the first inlet, and that intercepts the second valve (115) .

5. An assembly of manoeuvre (1), as per one or more of the preceding claims, wherein said means (125, 120, 200) to generate a signal comprise a stem (125) arranged slidingly in a sliding seat, in such a way that, once the threshold pressure, value measured has been reached, the valve opens allowing the inlet of the fluid in the sliding seat and causing the translation of the stem, said translation of the stem generating a signal through a block assembly (120, 200) with which it is cooperating.

6. An assembly of manoeuvre (1), as per claim 5, wherein the sliding seat is in fluid communication with the pressure valves downstream of the pressure valve on the opposite part to the inlet ( 14 ' ' , 14 ' ' ' ) .

An assembly of manoeuvre (1), as per claim 5 or 6, wherein said block assembly (120, 200) comprises an arm (120) and an assembly of electric knives (200), the arm (120) being hinged to the friction device (100) in such a way as to rotate of a pre-determined quantity in correspondence of a translation of said stem (125) to which it results connected, said arm (120) having an end cooperating with the assembly of electric knives (200) arranged in such a way that said assembly (200) generates a pre-determined electrical signal in correspondence of said rotation of the arm.

An assembly of manoeuvre (1) , as per claim 7, wherein said assembly of electric knives (200) comprises a rotatable drum (210) provided with one or more blades (220), the drum comprising a toothing (250) which engages with a corresponding toothing of the arm (120) in such a way that the rotation of the arm (120) through said toothing is transmitted to the drum that brings the blades (220) in a pre-determined position for the generation of a specific electrical signal.

A friction device (100) for detecting an obstacle that impedes the manoeuvre in an assembly of manoeuvre of a switch point, said friction device being suitable for resulting connectable in a circuit (4' , 4'', _.14', 14'', 14''') of said assembly of manoeuvre and comprising:

- A path (160_/ 161, 162) for receiving the fluid circulating in the circuit;

- At least one pressure valve (110, 115) arranged in such a way as to intercept the fluid coming in in the path (160, 161, 162) and detecting the pressure value thereof,

characterized in tha.t said pressure valve is configured in such a way as to obstruct said path

(160, 161, 162) for pressure values below a pre- established threshold value and open to allow the flow once reached or exceeded said threshold value;

And wherein means (125, 120, 200) are further foreseen to generate a signal, preferably an electrical signal/

Said means (125, 120, 200) being arranged in the friction device in fluid communication with said path

(160, 161, 162) in such a position as to intercept the circulating fluid following the opening of the pressure valve, said means being further configured to be activated through the pressure of the fluid with which they enter into contact.

A friction device (100) , as per claim 9, wherein the following are foreseen:

A friction device (100), as per claim 9 or 10, wherein said means (125, 120, 200) comprise a stem. (125) arranged slidingly in a sliding seat in such a way that once said threshold pressure value has been reached, the corresponding valve opens, allowing the inlet of the fluid in the sliding seat and causing the translatlon of the stem, said translation of the stem generating said signal through a block assembly (120, 200) with which it is cooperating,

12. A friction device (100), as per claim 11, wherein said block assembly (120, 200) comprises an arm (120) and an assembly of electric knives (200), the arm (120) being hinged to the friction device (100) in such a way as to rotate of a pre-determined quantity in correspondence of a translation of said stem (125) to which it results connected, said arm (120) having an end cooperating with the assembly of electric knives (200) arranged in such a way that said assembly (200) generates a pre-determined electrical signal in correspondence of said rotation of the arm.

13. A friction device (100), as per claim 12, wherein said assembly of electric knives (200) comprises a rotatable drum (210) provided with one or more blades (220) , the drum comprising a toothing (250) which engages with a corresponding toothing of the arm (120) in such a way that the rotation of the arm (120) through said toothing is transmitted to the drum that brings the blades (220) in a pre-determined position for the generation of a specific electrical signal.

14. A friction device (100), as per one or more of claims from 9 to 13, wherein the two valves have each one a different threshold pressure value.