Position indication system, self-locking shock absorber device and associated control method.

Abstract

This application relates to a position indication system (5) of a self-locking device (1) damping an installation, the self-locking device (1) comprising a fixed part (2), a movable part (3) capable of sliding relative to the fixed part (2) and a locking system configured to, on the one hand, allow the sliding of the movable part (3) in the event of a force applied to the movable part (3) below a predetermined threshold and, on the other hand, to block the sliding of the movable part (3) in the event of a force applied to the movable part (3) above the predetermined threshold, the position indication system (5) comprising: - A first position indicator (25) and a second position indicator (26); - A measuring tool (19) on which the first position indicator (25) and the second position indicator (26) are mounted;- A first support (6) for the measuring tool and a second support (7) for the measuring tool carrying the measuring tool (19), the first support (6) being intended to be fixed to the fixed part (2) of the self-locking device (1), the second support (7) being intended to be fixed to the moving part (3) of the self-locking device (1). Figure for the abbreviation: Fig. 2A;

Description

Title of the invention: Position indication system, self-locking damping device and associated control method. Technical field

[0001] The present application relates to the field of self-locking damping devices. It relates more particularly to a system for indicating the position of a self-locking damping device, as well as a method for controlling such a self-locking damping device.

[0002] The present application also relates to a self-locking shock absorber device. STATE OF THE ART

[0003] In many industrial fields such as aeronautics, nuclear power, petrochemicals or even photovoltaic power plants, components of different types such as pipes, tanks, valves may be subjected to sudden undesirable movements. Such movements may be the result of phenomena external to the installation comprising the component such as an earthquake, or the result of phenomena internal to the installation such as a breakage of a component, a valve opening, a water hammer, etc.

[0004] These sudden movements can be very harmful and cause damage to the components subjected to them. This is why it is necessary to protect these components, for example by holding them still using a holding system.

[0005] On the other hand, these components may require the ability to perform less violent light movements. For example, a pipe may be required to thermally expand under the effect of a fluid passing through it brought to a very high temperature, as is often the case in the nuclear industry.

[0006] To meet these two requirements, self-locking damping devices, also commonly called self-locking devices, have been developed. Such a self-locking device is a damper connected at one end to the component to be damped and at an opposite end to a fixed frame. This device is capable, on the one hand, of allowing slight movements of the component and, on the other hand, of locking itself in the event of sudden movement, in order to keep the component immobile and thus protect it.

[0007] Such a self-locking device generally comprises a fixed part and a movable part capable of sliding relative to the fixed part, such that the self-locking device is configured to expand or compress according to the slow movements of the damped component.

[0008] In certain high-risk industries such as nuclear power, self-locking devices are often used to protect equipment important to safety (EIPS), such as Basic Nuclear Installations (BNI). Therefore, it is necessary to regularly check the operation of such a self-locking device. These checks must be carried out in different states of the installation (in operation, at a standstill, during cooling just after the standstill), in order to ensure that the self-locking device being checked operates correctly without blocking during operation (when hot, for example) and / or when stopped (when cold, for example).

[0009] More precisely, these checks take the form of positioning readings of the self-locking device, which are taken at different times corresponding to the different states of the installation, for example when stopped and in operation, states in which the self-locking device is supposed to occupy a more compressed position and a more extended position.

[0010] However, these measurements are carried out manually by agents, for example using a manual measuring tool. This has several drawbacks.

[0011] First of all, the measurements taken may vary depending on the agents and the measuring tools used, which degrades the accuracy of the control carried out. Then, the measurements are made live, that is to say when the self-locking device occupies the measured position of interest of compression, extension, etc. This multiplies the number of readings taken by the agent, who must therefore come into contact with the self-locking device several times. This results in an impact in terms of time and resources. In addition, self-locking devices regularly dampen components at very high temperatures, which induces risks of injury for the agents carrying out the control. Similarly, in the case of a nuclear installation, self-locking devices are placed in areas with radiological activity. It is therefore important to limit the number of readings taken by the agent in contact with the self-locking device.

[0012] Another disadvantage induced by manual measurement is that, during readings, agents sometimes make mistakes in their measurement, especially since the measurement points can vary depending on the model of self-locking device being checked.

[0013] Also, when a measurement is forgotten or poorly carried out by the agent, a complete check must be repeated, which proves to be costly in terms of time and can prove dangerous for the installation by delaying the detection of a possible fault in the self-locking device. EXPOSE

[0014] An aim of the present application is to remedy the aforementioned drawbacks, by proposing a system for indicating the position of a self-locking device.

[0015] The present application also aims to propose a self-locking device and an associated control method.

[0016] To this end, according to a first aspect, a system for indicating the position of a self-locking device damping an installation is proposed, the self-locking device

[0017]

[0018]

[0019]

[0020]

[0021]

[0022] comprising a fixed part, a movable part capable of sliding relative to the fixed part and a locking system configured to, on the one hand, allow the sliding of the movable part in the event of a force applied to the movable part less than a predetermined threshold and, on the other hand, to block the sliding of the movable part in the event of a force applied to the movable part greater than the predetermined threshold, the position indication system comprising: - A first position indicator and a second position indicator; - A measuring tool on which the first position indicator and the second position indicator; - A first support for the measuring tool and a second support for the measuring tool carrying the measuring tool, the first support being intended to be secured to the fixed part of the self-locking device, the second support being intended to be secured to the movable part of the self-locking device. Thus, the position indication system constitutes a means of quickly and reliably reading and deducing a maximum distance traveled in compression and a maximum distance traveled in extension by the moving part of the self-locking device. In addition, the position indication system is suitable for any self-locking device, and allows identical reading and deduction of these distances traveled for any self-locking device. Accuracy is therefore improved. Preferably, the measuring tool: - is mounted fixed relative to the second support, and - is able to slide relative to the first support under the thrust effect of the second support when the moving part slides. Preferably, the first position indicator and the second position indicator are mounted on the measuring tool on either side of the first support, the second position indicator being mounted on the measuring tool between the first support and the second support. Thus, the first support constitutes a stop means capable of moving the position indicators according to the movement of the movable part of the self-locking device. Advantageously, each of the first and second position indicators is configured on the one hand to translate along the measuring tool when said position indicator comes into contact with the second support acting as a stop, and on the other hand to translate with the measuring tool while remaining in the same position along the measuring tool in the absence of contact with the second support. Thus, the position indicators are only moved along the measuring tool if the first support stops against them in their direction of movement. In this way, the maximum compression and extension distances traveled by the self-locking device can be deduced from the positions occupied by the indicators of positions along the measuring tool.

[0023] Preferably, each of the first and second supports comprises a lower part and an upper part secured to the lower part, the measuring tool being mounted between the upper part and the lower part, the upper part and the lower part being fixed to each other by means of a fixing device such as a threaded rod.

[0024] In one embodiment, one of the first and second supports comprises a spacer fixed between the lower part and the upper part, the measuring tool being mounted between the spacer and the upper part, the spacer being fixed to the upper and lower parts by means of the fixing device.

[0025] Such a spacer makes it possible to position the measuring tool substantially parallel to the self-locking device by compensating for differences in diameter between the fixed part and the mobile part of the controlled self-locking device.

[0026] Advantageously, the measuring tool is a graduated ruler.

[0027] Preferably, the measuring tool comprises an oblong opening extending along the measuring tool and a passage hole, the first support passing through the oblong opening and the second support passing through the passage hole, the oblong opening being configured to allow the first support to slide relative to the measuring tool along said oblong opening, and the passage hole being configured to grip the second support and prevent said second support from sliding relative to the measuring tool.

[0028] In a preferred embodiment, the measuring tool comprises a breakable portion capable of breaking in the event of the measuring tool becoming blocked, tending to prevent movement of the self-locking device.

[0029] Thus, the position indication system does not exert any force likely to disrupt the operation of the controlled self-locking device.

[0030] The invention also relates to a self-locking device intended to cushion an installation, comprising: - a fixed part; - a movable part capable of sliding relative to the fixed part; - a locking system configured to, on the one hand, allow movement of the moving part in the event of a force applied to the moving part less than a predetermined threshold and, on the other hand, to block the movement of the moving part in the event of a force applied to the moving part greater than the predetermined threshold,

[0031] Advantageously, the self-locking device comprises an indication system as defined previously.

[0032] The invention also relates to a method for controlling a self-locking device as defined above, the self-locking device being mounted between an ins- tallation and a fixed frame, the method comprising the following steps: - Setting the first position indicator and the second position indicator to an initial position in contact with the first support; - Commissioning of the installation; - Achieving a stable operating regime for the installation; - Stopping the operation of the installation; - Determination of a maximum distance traveled in compression and a maximum distance traveled in extension by the self-locking device. DESCRIPTION OF FIGURES

[0033] Other characteristics, aims and advantages of the subject of the application will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0034] [Fig.l] illustrates a longitudinal sectional view of a self-locking device without a position indication system;

[0035] [Fig.2A] and [Fig.2B] respectively illustrate a schematic perspective and profile view of the self-locking device of [Fig.1], on which a position indicating system according to the present application is attached;

[0036] [Fig.3] and [Fig.4] respectively illustrate a perspective and profile view of a lower part of the supports of the position indication system;

[0037] [Fig.5] and [Fig.6] respectively illustrate a perspective and profile view of an upper part of the supports of the position indication system;

[0038] [Fig.7] illustrates a top view of a measuring tool of a position indicating system according to the present application;

[0039] [Fig.8] illustrates a perspective view of a spacer of a support of the position indicating system according to the present application;

[0040] [Fig.9] illustrates a perspective view of a position indicating part of a position indicator of the position indicating system according to the present application;

[0041] [Fig. 10] illustrates a perspective view of a support plate of a position indicator of the position indicating system according to the present application;

[0042] [Fig.11], [Fig.12], [Fig.13], [Fig.14] and [Fig.15] illustrate in top view the positioning of the self-locking device and the position indication system during different possible operations of the self-locking device;

[0043] [Fig. 16] schematically illustrates the different stages of a method for controlling a self-locking device equipped with a position indication system in accordance with an embodiment of the application.

[0044] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION

[0045] [Fig.l] illustrates a self-locking device 1 in schematic view and in longitudinal section. The self-locking device 1 corresponds in its damping operation to a conventional self-locking device and will now be described briefly.

[0046] The self-locking device 1 is intended to be arranged between a fixed frame B and an installation I to be damped and protected. The installation I is, for example, a pipe of a nuclear installation in which a fluid at very high temperature circulates. The installation I is thus capable of applying so-called slow movements, for example thermal expansion, to the self-locking device 1.

[0047] The self-locking device 1 comprises a fixed part 2, a movable part 3 capable of sliding relative to the fixed part 2, and a locking system 4. The fixed part 2 is attached to the fixed frame B, and the movable part 3 is attached to the installation I. Or conversely, the fixed part 2 can be attached to the installation, the movable part being attached to the fixed frame B.

[0048] The movable part 3 is movable between a first extreme position called the maximum compression position in which the self-locking device 1 extends over a minimum distance and a second extreme position called the maximum extension position in which the self-locking device 1 extends over a maximum distance. The distance between the extreme extension and compression positions is for example between 100 and 750 millimeters.

[0049] In the embodiment of [Fig.l], the movable part 3, during its sliding, is able to be inserted into the fixed part 2. Alternatively, the movable part 3 can, during its sliding, surround and cover the fixed part 2.

[0050] The movable part 3 may comprise a rod 3a and a piston 3b carried by the rod 3a. The fixed part 2 may be a cylinder in which the rod 3a carrying the piston 3b slides.

[0051] Thus, the self-locking device 1 may comprise a first chamber 1a and a second chamber 1b arranged on either side of the piston 3b. The locking system 4 comprises a valve 4a capable of allowing the movement of a viscous fluid from one chamber 1a, 1b to the other during the movement of the piston 3b. The valve 4a takes for example the form of a hole passing through the piston 3b and connecting the chambers 1a and 1b.

[0052] The valve 4a is dimensioned to define a blocking threshold of the self-locking device 1. More precisely, the diameter of the hole forming the valve 4a defines a maximum flow rate and therefore a maximum sliding speed of the movable part 3 relative to the fixed part 2, below which the necessary flow rate of viscous liquid passing from one chamber 1a, 1b to the other to allow the movement of the movable part 3 is less than said maximum flow rate, and beyond which the necessary flow rate of the viscous liquid passing from one chamber to the other to allow the movement of the mobile part 3 is greater than said maximum flow rate.

[0053] In other words, the locking system 4 is thus configured to, on the one hand, allow the sliding of the mobile part 3 in the event of a force applied to the mobile part 3 less than a threshold and, on the other hand, to block the sliding of the mobile part 3 in the event of a force applied to the mobile part 3 greater than the threshold.

[0054] Figures 2A and 2B illustrate a position indicating system 5 according to the present application. In Figures 2A and 2B, the position indicating system 5 is mounted on the self-locking device 1.

[0055] The position indication system 5 comprises a first support 6 and a second support 7.

[0056] The first support 6 is fixedly mounted on the fixed part 2, and the second support 7 is fixedly mounted on the movable part 3. The first support 6 and the second support 7 extend perpendicularly to the self-locking device 1. For example, in order not to damage the self-locking device 1 as screwing could do, the first support 6 and the second support 7 are mounted on the self-locking device 1 by means of a clamping collar (not shown in the figures) surrounding the self-locking device 1 or any other suitable system.

[0057] The first support 6 and the second support 7 are identical. In particular, they each comprise a lower part 8 and an upper part 9. The lower part 8 is arranged on the self-locking device 1, and the upper part 9 is arranged on the lower part 8.

[0058] The lower part 8 is illustrated in perspective in [Fig.3] and in profile in [Fig.4].

[0059] The lower part 8 comprises a lower surface 8a intended to be positioned in facing the self-locking device 1, an upper surface 8b opposite the lower surface 8a, and a peripheral surface 8c connecting the upper surface 8a to the lower surface 8b.

[0060] The lower part 8 comprises four feet 10 extending from the lower surface 8a and which are intended to rest on the self-locking device 1 to increase the stability of the position indication system 5.

[0061] The lower part 8 is for example machined from a round piece of S235 steel 16 millimeters in diameter and 11.5 millimeters in height. Alternatively, the lower part 8 can be made of any other suitable material.

[0062] For example, the four feet 10 are machined over a distance of 2 millimeters in the height of the lower part 8.

[0063] The lower part 8 is drilled over its entire height defined between the lower surface 8a and the upper surface 8b, this drilling having a first tapping 11 of the lower part 8. For example, the first tapping 11 produced is in M8, that is to say with a diameter of 8 millimeters.

[0064] To fix the lower part 8 to the self-locking device 1, the lower part 8 may comprise a through-hole 12 opening on either side of the lower part 8, more precisely of the peripheral surface 8c. The clamping collar can thus pass through the lower part 8 via the through-hole 12, and thus fix the part 8 to the self-locking device 1.

[0065] The lower part 8 may comprise two flats 14 machined on either side of the peripheral surface 8c so as to allow the use of a tightening key on the lower part 8. For example, the two flats 14 measure 5 millimeters wide in the height of the lower part 8, and are hollowed out to a depth of 1.5 millimeters in the peripheral surface 8c.

[0066] The through light 12 extends into the lower part 8 between the two plates 14. The through light measures 3 millimeters in the height of the base part 8.

[0067] Finally, the lower part 8 comprises a collar 15 extending from the upper surface 8b, the collar 15 forming a hollow circular protrusion coaxially extending the first tapping 11 of the lower part 8. The collar 15 may extend for example over a height of 1.5 millimeters, and have a diameter of 10 millimeters.

[0068] The diameter of the collar 15 is greater than the diameter of the first thread 11, so as not to prevent the introduction of a fixing device such as a threaded rod into the first thread 11 via the upper surface 8b.

[0069] The upper part 9 is illustrated in perspective in [Fig.5] and in profile in [Fig.6].

[0070] The upper part 9 comprises a lower surface 9a intended to be positioned in view of the lower part 8, an upper surface 9b, and a peripheral surface 9c connecting the lower surface 9a to the upper surface 9b.

[0071] The upper part 9 is drilled over its entire height between the lower surface 9a and the upper surface 9b, this drilling defining a second tapping 17 of the same diameter as the first tapping 11 of the lower part 8, and opening respectively onto the lower surface 9a and onto the upper surface 9b.

[0072] For example, part 9 is machined from a steel round 16 millimeters in diameter and 10 millimeters in height.

[0073] Two flats 18 can be machined on two opposite areas of the peripheral surface 9c, so as to allow the use of a tightening key on the upper part 9. For example, the two flats 18 are of the same dimensions as the two flats 14 of the lower part 8.

[0074] The lower part 8 and the upper part 9 are secured to each other, for example by means of a fixing device such as a threaded rod introduced into the lower 8 and upper 9 parts cooperating with the threads 11 and 17. The lower part 8 is thus arranged between the self-locking device 1 and the upper part 9.

[0075] Furthermore, the position indicating system 5 comprises a measuring tool 19 mounted on the first support 6 and on the second support 7. An example of the measuring tool 19 is illustrated in [Fig.7]. The measuring tool 19 comprises a graduated upper surface 19a illustrated in [Fig.7], and a lower surface intended to be positioned opposite the self-locking device 1. For example, the measuring tool 19 is a graduated ruler.

[0076] Once mounted, the measuring tool 19 extends parallel to the self-locking device 1 and therefore in the sliding direction of the movable part 3, i.e. perpendicular to the first support 6 and to the second support 7.

[0077] The measuring tool 19 comprises an oblong opening 20a and a through hole 20b machined in its thickness between its lower surface and its upper surface 19a.

[0078] The measuring tool 19 is mounted on the first support 6 and the second support 7. More precisely, the first support 6 passes through the oblong opening 20, and the second support 7 passes through the passage hole 20b.

[0079] The passage hole 20b is for example machined on one end of the measuring tool 19.

[0080] The walls defining the through-hole 20b enclose the second support 7 so that the second support 7 cannot translate relative to the measuring tool 19. More precisely, the measuring tool 19 is mounted between the lower part 8 and the upper part 9 of the second support 7, the walls of the through-hole 20b surrounding and enclosing the collar 15 of the lower part 8 of the second support 7. The through-hole 20b therefore has, for example, the shape of a circle with a diameter substantially equal to, but slightly greater than, the diameter of the collar 15 of the second support 7. For example, the through-hole 20b has a diameter half a millimeter greater than the diameter of the collar 15 of the lower part 8 of the second support 7.

[0081] Thus, when the second support 7 slides with the movable part 3, the second support 7 causes the measuring tool 19 to slide, by a support and a pushing force of the collar 15 of the second support 7 against a wall of the passage hole 20b. The measuring tool 19 is therefore mounted fixed relative to the second support 7.

[0082] The passage hole 20b is thus configured to prevent the second support 7 from sliding relative to the measuring tool 19, and to secure in movement the measuring tool 19 with the second support 7 and therefore the movable part 3.

[0083] The oblong opening 20a extends rectilinearly along the measuring tool 19 between the through hole 20b and an end of the measuring tool 19 opposite the through hole 20b. The oblong opening 20a extends parallel to the sliding direction of the self-locking device 1 and the second support 7.

[0084] The measuring tool 19 is arranged between the lower part 8 and the upper part 9 of the first support 6. More precisely, the oblong opening 20a surrounds the collar 15 of the lower part 8 of the first support 6.

[0085] The oblong opening 20a is sufficiently wide to allow, when the movable part 3 slides, sliding of the measuring tool 19 relative to the first support 6 without blocking the first support 6. For example, the oblong opening 20a has a width half a millimeter greater than the diameter of the collar 15 of the lower part 8 of the second support 7. “Width” means the dimension of the oblong opening 20a perpendicular to the direction of extension of the opening 20a.

[0086] On the other hand, the oblong opening 20a is sufficiently long to allow the measuring tool 19 to slide relative to the first support 6 without blocking said first support 6 between the extreme compression position and the extreme extension position of the self-locking device 1. The oblong opening 20a therefore has a length at least equal to the distance between the extreme compression position and the extreme extension position. The term “length” means the dimension of the oblong opening 20a in the direction of sliding of the measuring tool 19.

[0087] The oblong opening 20a is therefore configured to allow the self-locking device 1 to slide between the extreme compression and extension positions without blocking the first support 6.

[0088] The measuring tool 19, the upper part 9 and the lower part 8 of the first support 6, respectively of the second support 7, are held together due to the fixing device of the first support 6, respectively of the second support 7, which therefore successively passes through the upper part 9, the passage hole 20b, respectively the oblong opening 20a, and the lower part 8.

[0089] Optionally, the first support 6 or the second support 7 may comprise a spacer 21 arranged between the lower part 8 and the upper part 9, in order to compensate for a difference in diameter between the mobile part 3 and the fixed part 2, and thus allow parallel positioning of the measuring tool 19 to the self-locking device 1.

[0090] An example of such a spacer 21 is illustrated in [Fig.8] in perspective.

[0091] The spacer 21 comprises a lower surface 21a facing the lower part 8, an upper surface 21b facing the upper part 9 and a peripheral surface 21c. The spacer 21 is pierced in its height between the lower surface 21a and the upper surface 21b, said drilling comprising a tapping 22 identical to those of the lower part 8 and the upper part 9. The spacer 21 comprises a collar 23 extending from the upper surface 21b, identical to the collar 15 of the lower part 8. In addition, a cavity for receiving the collar 15 of the lower part can be hollowed out in the lower surface 21a of the spacer, in order to facilitate the securing of the spacer 21 and the lower part 8 by insertion of the collar 15 of the lower part 8 into said cavity. Also, two plates 24 identical to plates 14 and 18 can be machined on two opposite areas of the peripheral surface 21c of the spacer 21 to facilitate the use of a tightening wrench.

[0092] When one of the first and second supports 6 and 7 comprises a spacer 21, the measuring tool 19 surrounds the collar 23 of the spacer 21 instead of the collar 15 of the lower part 8. The collar can make it possible to raise the measuring tool 19 for example by less than 10 millimeters to 20 millimeters or more depending on the height of the spacer 21, which is chosen as a function of the difference in diameter between the mobile part 3 and the fixed part 2. It is in particular preferable to use a spacer 21 of a height equal to said difference in diameter between the mobile part 3 and the fixed part 2.

[0093] Each of the upper 9 and lower 8 parts, and the spacer 21, can be individually made from a steel round of suitable dimensions.

[0094] Furthermore, the position indicating system 5 may comprise a first position indicator 25 and a second position indicator 26 identical to each other in their shape and differing only in their positioning and orientation, and which will now be described.

[0095] The first position indicator 25 and the second position indicator 26 are mounted on the measuring tool 19 on either side of the first support 6, the second position indicator 26 being mounted on the measuring tool 19 between the first support 6 and the second support 7. More precisely, the first position indicator 25 and the second position indicator 26 are mounted on the measuring tool 19 by passing through the oblong opening 20a.

[0096] Each of the first position indicator 25 and the second position indicator 26 includes a position indicator part 27 shown in perspective in [Fig. 9] and a backing plate 28 shown in perspective in [Fig. 10].

[0097] The position indicator part 27 and the support plate 28 of each position indicator 25, 26 are arranged on either side of the measuring tool 19.

[0098] The position indicator part 27 is a plate such as a flat iron, comprising a lower surface 27a resting on the measuring tool 19, and an upper surface 27b.

[0099] The position indicator part 27 has a width greater than the width of the oblong opening 20a so as not to pass through said oblong opening 20a, possibly even greater than the width of the measuring tool 19. For example, the position indicator part 27 has a width of 25 millimeters. The position indicator part 27 has a length greater than the radius of the upper part 9, for example about 15 millimeters. Finally, the position indicator part 27 has a thickness of about 2 millimeters between the lower surface 27a and the upper surface 27b. “Width” means the dimension of the position indicator part 27 along the direction of the width of the oblong opening 20, and “length” means the dimension of the position indicator part 27 along the direction of the length of the opening oblong 20.

[0100] The position indicator part 27 comprises an end 30 facing the first support 6 having a semicircular hole with a radius equal to the radius of the upper part 9 of the first support 6, and centered at a midpoint of the width of this end 30. This end 30 is thus configured to surround the first support 6, and more precisely the upper part 9 of the first support 6, as illustrated in [Fig.2A]. The end 30 has a width greater than the diameter of the upper part 9 of the first support 6, so that the end 30 comprises, on either side of the semicircular hole, a first tab and a second tab comprising a respective free end 31a and 31b constantly aligned with a single point of the graduation of the measuring tool 19. These free ends 31a and 31b thus define a reading point for the position of their position indicator 26, 27.

[0101] Optionally, the position indicator part 27 may comprise two shoulders 32 extending from its lower surface 27a to define a space for receiving the measuring tool 19 facilitating the positioning of the position indicator part 27 on the measuring tool 19. These shoulders 32 may for example extend over 1 millimeter from the lower surface 27a, and are for example machined on the width ends of the indicator part 27.

[0102] The support plate 28 is also a plate such as a flat iron, and comprises a lower surface 28a facing the self-locking device 1 and an upper surface 28b facing the measuring tool 19. The support plate 28 has a width greater than the width of the oblong opening 20a so as not to pass through said oblong opening 20. For example, the support plate 28 has a width of approximately 21 millimeters. The support plate 28 has a length, for example, of approximately 5 millimeters. Finally, the support plate 28 has a thickness of approximately 3 millimeters between the lower surface 28a and the upper surface 28b. The term "width" refers to the dimension of the support plate 28 along the width direction of the oblong opening 20, and the term "length" refers to the dimension of the support plate 28 along the length direction of the oblong opening 20.

[0103] Each of the position indicator part 27 and the support plate 28 are drilled through their thickness by an identical bore 40 having a thread (not shown), for example in M3, in order to secure them by means of a fixing rod. Alternatively, only the position indicator part 27 and / or the support plate is threaded, for example in M3. In the latter case, the bore of the non-threaded part is of a slightly larger diameter, for example 1 millimeter. The fixing rod of each of the first and second position indicators 25, 26 therefore successively passes through the position indicator part 27, the measuring tool 19 (the oblong opening 20) and the support plate 28, so as to secure the position indicator 25, 26 with the measuring tool 19.

[0104] For each of the first and second position indicators 25 and 26, the clamping via the fixing rod of the position indicator part 27, of the support plate 28 and of the measuring tool 19 is carried out so as to prevent the movement of said position indicator 25, 26 along the measuring tool 19 in the absence of an external force from a stop on said position indicator 25, 26, and to allow the movement of said position indicator 25, 26 along the measuring tool 19 during such an external force on said position indicator 25, 26.

[0105] The only element that can come into abutment against the first position indicator 25 and the second position indicator 26 is the first support 6, and in particular its upper part 9, when the measuring tool 19 slides relative to the fixed part 2 and therefore relative to said first support 6. Thus, each of the first and second position indicators 25 and 26 is configured on the one hand to slide along the measuring tool 19 when said position indicator 25, 26 comes into contact with the first support 6 acting as a stop, and on the other hand to slide with the measuring tool 19 relative to the fixed part 2 while remaining in the same position along the measuring tool 19 in the absence of contact with the first support 6.

[0106] Thus, during operation of the installation I, the first and second position indicators 25 and 26 are caused to be moved along the measuring tool 19 from an initial position as a function of the sliding in extension or compression of the self-locking device 1.

[0107] The initial position is for example the position in which each of the first and second position indicators 25 and 26 are arranged in contact with the first support 6 and surround it, the reading points of said first and second position indicators 25 and 26 formed by their respective ends 31a and 31b being in contact with each other and aligned with the center of the first support and with a graduation of the measuring tool 19 forming a zero measurement point 41 of the graduation of the measuring tool 19. This initial position is illustrated in [Fig. 12], the zero measurement point being marked by a cross 41 on the measuring tool 19.

[0108] An example of operation of the position indication system 5 will now be described with reference to figures 11 and following:

[0109] At a time t0, the position indicating system is at the initial position as illustrated in [Fig. 11].

[0110] The installation is then put into operation. In the present example, it is considered that the operation of the installation I causes a thermal expansion of the installation I, which compresses the self-locking device 1. The movable part 3 then slides towards the fixed part 2, for example until a time t1 illustrated in [Fig. 12]. Consequently, the second support 7 causes the tool to slide measurement 19 in the same direction. During this sliding, the first support 6 does not come into abutment with the first position indicator 25, which therefore slides with the measuring tool while remaining in the same position along the measuring tool 19. In addition, not having been blocked by the first support 6, the first position indicator 25 has constantly remained aligned with the zero measurement point 41, which therefore occupies the same position at time tl as the ends 31a and 31b of the first position indicator 25. On the contrary, during this sliding, the first support 6 forms a stop and retains the second position indicator 26, the position of which along the measuring tool 19 changes accordingly. Thus, at time tl illustrated in [Fig. 12], a gap is defined between the first and second position indicators 25 and 26, of a value equal to the sliding distance achieved by the moving part 3 between t0 and tl.

[0111] The operation of the installation I is then stopped. In the present example, the temperature drops so that the installation I undergoes a thermal contraction. The movable part 3 then slides in the opposite direction to the sliding direction between t0 and t1 initially until a time t2 illustrated in [Fig. 13]. Consequently, the second support 7 slides the measuring tool 19 in the same direction. At time t1, neither of the first and second position indicators 25 and 26 is able to be retained by the first support 6 in this sliding direction, so that each of the first and second position indicators 25 and 26 slides with the measuring tool 19 while remaining at the same position along the measuring tool 19, as illustrated in [Fig. 13]. Likewise, the measuring zero point 41 remains aligned with the ends 31a and 31b of the first position indicator 25. [Fig.13] therefore illustrates a situation in which, in the present example, the installation is cooled to a temperature which remains higher than the initial temperature at time t0, that is to say a situation in which the sliding in compression of the mobile part 3 was greater than its sliding in extension.

[0112] When the cooling (and therefore the thermal contraction) of the installation I continues and at a time t3, the installation I returns to its initial temperature of time t0, the position indication system 5 occupies the position illustrated in [Fig. 14]. The movement between times t1 and t2 of Figures 12 and 13 has continued until the first position indicator 25 is in its initial position of time t0. [Fig. 14] therefore illustrates a situation in which the sliding in extension of the mobile part 3 has been equal to its sliding in compression.

[0113] If the thermal contraction of the installation I continues until a time t5 illustrated in [Fig. 15], that is to say that the temperature of the installation continues to decrease and becomes lower than its initial temperature at t0 (such a case can arise in particular when at the initial time t0, the installation was not completely cooled since its last start-up), the mobile part 3 continues its sliding in the same direction as between times t1 and t3. However, unlike this period between t1 and t3, the first support 6 now forms a stop against the first position indicator 25 in this sliding direction, so that the first position indicator 25 changes position along the measuring tool 19 and increases the gap between the two position indicators 25 and 26, the second position indicator 26 not being blocked by the first support and therefore sliding with the measuring tool 19 while remaining in the same position along the measuring tool 19. In addition, the measurement zero point follows the movement of the measuring tool 19, so that at time t5, said measurement zero point 41 is located between the two position indicators 25 and 26. [Fig. 15] therefore illustrates a situation in which the sliding in extension of the movable part 3 is greater than its sliding in compression.

[0114] Thus, depending on various elements such as the spacing between the two position indicators 25 and 26, the relative positioning of these position indicators 25 and 26 with the measurement zero point 41 or even with the first support 6 at the time of the check by the agent and / or the conditions of control of the self-locking device 1 (for example, if at the initial instant, the installation I is completely stopped and cold), it is possible to determine a maximum distance traveled in compression by the self-locking device 1 and a maximum distance traveled in extension by the self-locking device 1 since the initial instant t0.

[0115] This use of the position indication system 5 makes it possible in particular to carry out a check of the self-locking device 1, for example during the maintenance of this self-locking device 1. The steps of this method are illustrated schematically in [Fig. 16], and will now be described.

[0116] In a first step E1, the position indication system 5 is placed in the initial control position illustrated in [Fig. 12] corresponding to the initial instant t0 described previously. This positioning is carried out manually by an agent, possibly by a suitable tool. In an alternative embodiment, this initial positioning can also be controlled electronically.

[0117] Preferably, the first step E1 is carried out when the installation I is stopped, so as to avoid risks for the agent, in particular of burning.

[0118] In a second step E2, the installation is put into operation. The installation then sees for example its temperature vary, causing for example a thermal expansion or a thermal contraction of the installation I causing a displacement of the mobile part 3, and more generally of the self-locking device 1 which compresses or extends. By moving, the mobile part 3 causes, by pressing the second support 7 on the measuring tool 19, a sliding of the measuring tool in the same sense and the same direction as the mobile part 3. By the mechanics described with reference to figures 11 to 15, the position indicators 25 and 26 are moved along the tool of measure 19 accordingly.

[0119] In a third step E3, a stable operating regime of the installation is reached. As a general rule, this regime corresponds to the moment of maximum expansion or maximum contraction, which is why it is important to reach this operating point with a view to maintaining the self-locking device 1 consisting of checking that the self-locking device 1 operates correctly without blocking.

[0120] In a fourth step E4, the operation of the installation I is stopped, which logically causes the measuring tool 19 to slide in the opposite direction by means of the movable part 3 and the second support 7.

[0121] In a fifth step E5, an agent checks the positioning of the first and second position indicators 25 and 26 using the graduation of the measuring tool 19, the relative positions of these position indicators 25 and 26 and the zero measurement point 41, and possibly of the first support 6, and deduces therefrom a maximum distance traveled in compression and a maximum distance traveled in extension by the self-locking device 1.

[0122] Depending on these maximum distances traveled in compression and extension by the self-locking device 1, it is possible to determine a state of health of the self-locking device 1 and, if necessary, to intervene to remedy an operating problem.

[0123] Finally, in order to prevent a force applied by the position indication system 5 to the self-locking device 1 which would be contrary to the movement of the self-locking device 1 and therefore to the performance of the damping function of the self-locking device 1, the measuring tool 19 may comprise a breakable portion 42 visible in [Fig. 7], which is configured to break and thus break the measuring tool 19 into two separate independent parts in the event of two opposing forces applied to the measuring tool 19 simultaneously, which would result, for example, in a blocking of the measuring tool 19. The breakable portion 42 therefore extends between two opposite ends of the measuring tool 19.

[0124] Thus, the position indication system 5 makes it possible to implement a more precise control of the self-locking device 1, less risky for the agent because it makes it possible to be in contact with the self-locking device 1 only a reduced number of times. Finally, this solution is inexpensive and applicable indifferently to any self-locking device 1.

Claims

Claims

1. Position indication system (5) of a self-locking device (1) damping an installation (I), the self-locking device (1) comprising a fixed part (2), a movable part (3) capable of sliding relative to the fixed part (2) and a locking system (4) configured to, on the one hand, allow the sliding of the movable part (3) in the event of a force applied to the movable part (3) less than a predetermined threshold and, on the other hand, to block the sliding of the movable part (3) in the event of a force applied to the movable part (3) greater than the predetermined threshold, the position indication system (5) comprising: - A first position indicator (25) and a second position indicator (26); - A measuring tool (19) on which the first position indicator (25) and the second position indicator (26) are mounted;- A first support (6) of the measuring tool and a second support (7) of the measuring tool carrying the measuring tool (19), the first support (6) being intended to be secured to the fixed part (2) of the self-locking device (1), the second support (7) being intended to be secured to the movable part (3) of the self-locking device (1).;

2. System (5) according to claim 1, in which the measuring tool (19): - is mounted fixed relative to the second support (7), and - is able to slide relative to the first support (6) under the thrust effect of the second support (7) during the sliding of the movable part (3).

3. System (5) according to claim 1 or 2, wherein the first position indicator (25) and the second position indicator (26) are mounted on the measuring tool (19) on either side of the first support (6), the second position indicator (26) being mounted on the measuring tool (19) between the first support (6) and the second support (7).

4. System (5) according to claim 3, wherein each of the first and second position indicators (25, 26) is configured on the one hand to translate along the measuring tool (19) when said indicator position (25, 26) comes into contact with the second support (7) acting as a stop, and on the other hand to translate with the measuring tool (19) while remaining in the same position along the measuring tool (19) in the absence of contact with the second support (7).

5. System (5) according to one of claims 1 to 4, in which each of the first and second supports (6, 7) comprises a lower part (8) and a higher part (9) secured to the lower part (8), the measuring tool (19) being mounted between the higher part (9) and the lower part (8), the higher part (9) and the lower part (8) being fixed to each other by means of a fixing device such as a threaded rod.

6. System (5) according to claim 5, wherein one of the first and second supports (6, 7) comprises a spacer (21) fixed between the lower part (8) and the upper part (9), the measuring tool (19) being mounted between the spacer (21) and the upper part (9), the spacer (21) being fixed to the upper (9) and lower (8) parts by means of the fixing device.

7. System (5) according to one of claims 1 to 6, in which the measuring tool (19) is a graduated ruler.

8. System (5) according to claim 7, wherein the measuring tool (19) comprises an oblong opening (20a) extending along the measuring tool (19) and a through hole (20b), the first support (6) passing through the oblong opening (20a) and the second support (7) passing through the through hole (20b), the oblong opening (20a) being configured to allow the first support (6) to slide relative to the measuring tool (19) along said oblong opening (20a), and the through hole (20b) being configured to grip the second support (7) and prevent said second support (7) from sliding relative to the measuring tool (19).

9. System (5) according to one of claims 1 to 8, in which the measuring tool (19) comprises a breakable portion (42) capable of breaking in the event of the measuring tool (19) becoming blocked, tending to prevent movement of the self-locking device (1).

10. Self-locking device (1) intended to cushion an installation (I), comprising: - a fixed part (2); - a movable part (3) capable of sliding relative to the fixed part (2); - a locking system (4) configured to, on the one hand, allow the movement of the mobile part (3) in the event of a force applied to the mobile part (3) less than a predetermined threshold and, on the other hand, to block the movement of the mobile part (3) in the event of a force applied to the mobile part (3) greater than the predetermined threshold, characterized in that the self-locking device (1) comprises an indication system according to one of claims 1 to 9.

11. Method for controlling a self-locking device (1) according to claim 10, the self-locking device (1) being mounted between an installation (I) and a fixed frame (B), the method comprising the following steps: - Setting to an initial position (El) the first position indicator (25) and the second position indicator (26) in contact with the first support (6); - Commissioning (E2) of the installation (I); - Achievement of a stable operating regime (E3) of the installation (I); - Stopping (E4) the operation of the installation (I); - Determination (E5) of a maximum distance traveled in compression and a maximum distance traveled in extension by the self-locking device (1).

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