EP2511449B1 - Prop with wear indicating means - Google Patents

Prop with wear indicating means Download PDF

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Publication number
EP2511449B1
EP2511449B1 EP12163678.1A EP12163678A EP2511449B1 EP 2511449 B1 EP2511449 B1 EP 2511449B1 EP 12163678 A EP12163678 A EP 12163678A EP 2511449 B1 EP2511449 B1 EP 2511449B1
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EP
European Patent Office
Prior art keywords
prop
axial compression
compression load
slide
indication
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Application number
EP12163678.1A
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German (de)
French (fr)
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EP2511449A1 (en
Inventor
Sébastien Philippe
Alexandre Souvignet
Pascal Perrotin
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Alphi SAS
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Alphi SAS
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Publication of EP2511449A1 publication Critical patent/EP2511449A1/en
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Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G25/00—Shores or struts; Chocks
    • E04G25/04—Shores or struts; Chocks telescopic
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/14—Telescopic props
    • E21D15/16—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure
    • E21D15/20—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure with pawl, pin, cross-piece, or the like engaging with ratchet teeth, notches, holes, or the like, spaced apart at intervals
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/14—Telescopic props
    • E21D15/16—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure
    • E21D15/24—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure with axial screw-and-nut, rack-and-worm, or like mechanism
    • E21D15/26—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure with axial screw-and-nut, rack-and-worm, or like mechanism with screw, worm, or the like, not self-locking but normally prevented from rotation by friction members which slip upon excessive pressure
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/14—Telescopic props
    • E21D15/46—Telescopic props with load-measuring devices; with alarm devices

Definitions

  • the present invention relates to the field of support elements normally used as a temporary vertical support on construction works, and more particularly relates to props with two telescopic tubes that can be moved one inside the other.
  • the standard NF EN 1065 describes two types of telescopic props, one with apparent net and the other with covered net. These telescopic props comprise two telescopic tubes called respectively barrel and slide, an approximate adjustment system using a pin inserted into the holes of the slide, and a precise adjustment system by a nut.
  • forestay is an aluminum stay such as that marketed under the name ALUPROP by ULMA.
  • This forestay has a shaft and a threaded slide externally.
  • the adjustment system of this strut comprises a nut cooperating by screwing with the external thread of the slide and having external dimensions allowing it to bear against the upper end of the barrel.
  • This type of forestay can however be made of a material other than aluminum.
  • a forestay In use, a forestay is subjected to a significant axial compression load likely to cause buckling and can deteriorate the forestay if it is too high. This compression load can sometimes bring the strut beyond its elastic limit value, that is to say that the strut has been deformed plastically by excessive buckling.
  • the document GB 844 137 A describes a strut according to the preamble of claim 1.
  • the means for indicating and storing this strut are arranged on the upper sole of the strut, which exposes them to a significant risk of fortuitous degradation during handling and handling.
  • the use of the forestay Indeed, during its handling and use, a forestay is placed on the ground according to its lower barrel end or according to its upper end of the slide, or even both, being placed abruptly on the ground.
  • the finalization of the establishment of a strut generally comprises an adjustment step in which an operator hammers the mass of the lower end of the barrel and / or the upper end of the slide. The means of indication and storage of this forestay are therefore strongly exposed to shocks that can lead to their degradation making them out of use or unable to fulfill their safety function.
  • the document FR 1 015 388 A discloses a strut with means for measuring and indicating an axial compression load supported by the strut. These means of measurement and indication are not reliable because the value of the load that will be indicated is a function of the total length of the forestay which can be more or less deployed according to the need for use.
  • the measuring and indicating means are expressly provided to be reversible so as to resume an initial indication state when the load applied to the stay ceases. It is thus impossible to know with certainty, after use, whether the strut has undergone or not excessive axial compression during its use and may have irreparably damaged its structure. A forestay damaged, but having no visually detectable anomaly, can thus be reused later and put in danger the operators of a building site.
  • a problem proposed by the present invention is to design a strut whose possible deterioration can be easily identified by any operator using means of indication properly protected against damage and unwanted operation.
  • the invention aims to design a forestay whose possible deterioration is reliably, unalterable, irreversible and definitive to avoid any risk of fraud and clumsiness, regardless of the length of use of the forestay.
  • the present invention provides a strut according to claim 1.
  • the means of indication and memorization allow the operator to discard the forestay, or set it aside for verification or maintenance.
  • the predetermined axial compression load value may be less than or equal to the theoretical limit load causing plastic deformation of the strut.
  • the indicating and memorizing means also make it possible to indicate safely and after the use of the strut, any exceeding of the predetermined axial compression load value which has occurred during the use of the strut. , this overshoot having been memorized. This allows operators not to reuse the forestay again but rather to scrap it or put it aside for verification or maintenance.
  • the indicating and memorizing means are adapted to be deformed permanently as soon as the axial compression load exceeds said predetermined axial compression load value.
  • a permanent deformation is a simple and effective means of memorization making it very difficult, even almost impossible, unintentional fraud or awkwardness in the materialization (indication and storage) of exceeding the predetermined axial compression load value.
  • the indicating and memorizing means are shaped so as to be arranged at least partly between the slide and the barrel, to take up the axial compression load applied to the strut.
  • the indication and storage means are thus arranged in an area which is less exposed to shocks during the handling and use of props than the lower end of the barrel or the upper end of the slide.
  • the strut may comprise means for limiting the penetration of the slide into the barrel, shaped so that, in the maximum retracted position of the strut, the upper end of the slide does not come into contact with the strut.
  • the indicating and memorizing means arranged between the slide and the barrel.
  • the indication and storage means may be integral with the strut.
  • the means of indication and storage are thus inseparable from the strut and therefore captive.
  • the indication and storage means can be reported on the forestay.
  • the indicating and memorizing means can thus be easily replaced in the case where, although the predetermined axial compression load value has been exceeded, the strut does not show, after verification, any deterioration liable to be endangered. the life of the operators.
  • reporting and storage means reported can be adapted on existing struts without having to modify them.
  • the strut advantageously comprises anti-disengagement means of the slide and the barrel, so that the strut must be disassembled at least partially to separate the slide and the barrel.
  • the means of indication and storage can not be removed without a voluntary action of disassembly, which is usually done using a specific tool.
  • the indication and storage means may be substantially in the form of a ring of internal diameter adapted to slidably receive the slide of the strut.
  • the means of indication and storage can thus be perceived from any direction away from the strut which therefore does not have to be oriented in a particular way by the operators during its installation.
  • the crown shape also allows quick assembly by simple engagement around the slide.
  • the permanent deformation may be a plastic deformation.
  • This mode of deformation not only makes it possible to memorize irreversibly the exceeding of the value of predetermined axial compression load, but also allows to memorize the maximum compressive load value to which the strut has been subjected. It is thus possible to better detect and analyze the defects of use by the operators and thus the causes of possible accidents.
  • the set of rods has a plastic buckling starting from the predetermined axial compression load value.
  • This load value can be fixed and predetermined by calculations and / or tests.
  • the sleeve has a plastic deformation starting from the predetermined axial compression load value.
  • This load value can be fixed and predetermined by calculations and / or tests.
  • the oblong deformation of the light under the effect of the axial compression load allows a simple and fast reading that the value of the predetermined axial compression load has been exceeded.
  • the permanent deformation can be a break. This mode of deformation is simple to perceive visually and to interpret. It indicates the exceeding of the predetermined axial compression load value unmistakably and irreversibly.
  • the indicating and memorizing means may comprise a colored liquid capsule to be broken when the axial compression load applied on the strut exceeds the value of the predetermined axial compression load, the indication and storage means. being shaped such that, after rupture, the colored liquid may flow out of the capsule and be perceived visually by an operator.
  • the liquid can easily be detected remotely by the operator and may further spread on the strut to mark it, preferably indelibly.
  • the indicating and storing means may comprise at least one ring intended to break when the axial compressive load applied to the strut exceeds the predetermined axial compression load value.
  • a telescopic strut 1 comprising two telescopic tubes, namely a barrel 2 and a slide 3, the slide 3 being slidably mounted in the barrel 2.
  • the slide 3 and the barrel 2 cooperate by sliding by means of respective portions 300 and 200 cylindrical.
  • the strut 1 comprises an approximate adjustment system 4 with a pin 5 which is inserted into one of the holes 6 of the slide 3 according to the desired length.
  • the strut 1 further comprises a precise adjustment system 7 by a nut 8. It can thus perfectly adjust the length L of deployment of the strut 1 according to the intended use.
  • the nut 8 covers the external thread 9 provided at the upper end 2a of the barrel 2.
  • Figures 1, 2 and 4 to 8 is thus of the type covered net according to standard NF EN 1065.
  • the strut 1 is adapted to support an axial compressive load by means of two flanges 10 and 11 ( figure 1 ).
  • the sole 10, carried by the shaft 2 is intended to rest on the ground while the sole 11, carried by the slide 3, is intended to bear directly or indirectly against the structure under construction to support.
  • the adjustment of the total length of the strut 1 is effected first with the approximate adjustment system 4: the slider 3 is taken out of the drum 2 to the desired approximate length, then the spindle 5 is engaged in the apparent hole 6 and located closer to the upper end 2a of the barrel 2.
  • the length adjustment of the strut 1 is then completed by using the precise adjustment system 7 by rotating the nut 8 with its handles 8a and 8b.
  • the strut 1 supports an axial compression load C corresponding to at least part of the weight of a structure under construction.
  • strut 1 comprises means for indicating and storing 12 an overshoot of the axial compression load beyond a predetermined axial compression load value.
  • the indicating and memorizing means 12 make it possible to report in a reliable and unalterable manner the fact that the axial compression load has exceeded the predetermined axial compression load value, which risks inducing a deterioration of the strut and therefore of inducing a danger for the operators.
  • the indicating and memorizing means 12 are shaped so as to be arranged between the slide 3 and the barrel 2 to take up the axial compression load C applied to the strut 1.
  • the means of indication and storage 12 are then substantially in the form of a ring of internal diameter D1 adapted to slidably receive the slide 3 of the strut 1 which has an outer diameter D2 smaller than the inner diameter D1.
  • the indicating and memorizing means 12 are more particularly interposed between the nut 8 and the pin 5, thus between the barrel 2 and the slide 3.
  • the indicating and memorizing means 12 are adapted to be permanently deformed when the load of axial compression experienced by the strut is greater than said predetermined axial compression load value.
  • permanent deformation is a plastic deformation.
  • the indicating and memorizing means 12 comprise a lower ring 13 and an upper ring 14 connected to one another by rods 15 uniformly distributed along the perimeter of the lower and upper rings 13 and 14.
  • the assembly constituted by the plurality of rods 15 has characteristics and a behavior in predetermined and known compression, for example by calculations or by carrying out tests.
  • the strut 1 Before deformation of the indicating and memorizing means 12, the strut 1 is as illustrated on the figures 1 and 2 .
  • the rods 15 hold the lower 13 and upper 14 rings at a distance d1, as long as the axial compression load C does not exceed the predetermined axial compression load value causing the deformation of the indicating and memorizing means 12.
  • the indicating and memorizing means 12 are deformed.
  • the rods 15 deform plastically by buckling as illustrated in FIG. figure 4 , so that the lower 13 and upper 14 rings are closer to each other.
  • the lower 13 and upper 14 rings are then distant by a distance d2 less than the distance d1.
  • the rods 15 having been plastically deformed, the distance d2 between the rings 13 and 14 is retained after use of the strut 1 which is then no longer subjected to an axial compression load.
  • the measurement of the distance d2 makes it possible to estimate the axial compressive load that the strut 1 has endured.
  • the lower ring 13 is secured to an outer cylindrical sleeve 16 slidably receiving an inner cylindrical sleeve 17 held by the upper ring 14.
  • the sleeves 16 and 17 can protect the rods 15 against accidental radial shocks.
  • the outer cylindrical sleeve 16 comprises slots 16a and 16b, while the inner cylindrical sleeve 17 has a color code and / or a graduated scale 17a apparent to through the lights 16a and 16b.
  • the indicating and memorizing means 12 comprise a sleeve 25 intended to surround the slide 3 over part of its length.
  • the sleeve 25 has a lower end 25a intended to rest on the barrel 2.
  • the sleeve 25 also comprises a support upper face 25b intended to take up the axial compression load C applied to the strut 1.
  • the upper face of Support support 25b receives pin 5 in support.
  • the sleeve 25 is thus interposed between the nut 8 of the barrel 2 and the pin 5 holding the slide 3.
  • the sleeve 25 is plastically deformed so that the upper support face 25b and the lower end 25a of the sleeve 25 come closer to each other.
  • the means of indicating and memorizing 12 of the figure 8 are particularly illustrated on the figure 9 .
  • the sleeve 25 has two slots 26 and 27 for receiving the pin 5 to prevent the slide 3 from sliding in the barrel 2.
  • the lights 26 and 27 are deformed and elongate in the axial direction II which coincides with the direction of application of the axial compression load C.
  • the portion of the sleeve 25 for plastically deforming is between the upper support surface 25b and the lower end 25a.
  • the sleeve 25 of the figure 9 after deformation due to exceeding the predetermined axial compression load value.
  • the light 26, initially circular ( figure 9 ) now has an elongated shape extending along the direction II.
  • the upper support face 25b and the lower end 25a are thus brought closer to one another under the effect of the axial compression load C.
  • the sleeve 25 has a marking line 28.
  • the marking line 28 When the upper support face 25b is below the marking line 28, this means that the lights 26 and 27 were deformed under the effect of the axial compression load C which exceeded the predetermined axial compression load value.
  • the marking line 28 thus has a graduation role. Several marking lines 28 are conceivable.
  • the indicating and storage means 12 comprise a colored liquid capsule 18 to be broken when the axial compression load C applied on the strut 1 exceeds the value of the predetermined axial compression load.
  • the indication and storage means 12 comprise a lower support ring 19 intended to come into contact with the nut 8 and an upper support ring 20 intended to bear against the pin 5.
  • a capsule 18 of colored liquid is interposed between the support rings 19 and 20.
  • the upper support ring 20 comes into contact with the lower support ring 19 by breaking the capsule 18 of colored liquid which then flows out of the capsule 18 and out of the indicating and memorizing means 12 by channels 21 provided for this purpose.
  • the colored liquid can then be perceived visually by an operator who is then warned of the risk.
  • the indicating and memorizing means 12 comprise a ring 22 intended to break when the axial compression load C applied on the strut 1 exceeds the predetermined axial compression load value.
  • the ring 22 has a cross section S made of a material provided such that the cross section S breaks when the axial compression load C exceeds the predetermined axial compression load value. An operator can easily perceive the risk visually as soon as the ring 22 is broken and / or absent.
  • indication and storage means 12 comprising a first ring 23 of substantially triangular cross-section and intended to rest on the nut 8, and a second ring 24 of triangular cross section and intended to come into contact with the pin 5.
  • the rings 23 and 24 are arranged and nested as illustrated on the figure 7 on which the ring 24 tends to expand radially ring 23 under the effect of the axial compression load C by a wedge effect.
  • the rupture and / or the absence of the ring 23 can easily be perceived visually by an operator who is then warned of the potential risk.
  • the ring 23 may have a cross-sectional shape other than triangular.
  • the ring 24 itself may also break when the axial compression load C applied on the strut exceeds another predetermined axial compression load limit value, greater than the predetermined axial compression load value which leads to ring 23 to break.
  • This provides progressive indication and storage means 12 capable of to signal the exceeding of different predetermined axial compression load values.
  • the indicating and storage means 12 are integral with the strut 1, to prevent their loss or fraudulent removal.
  • the lower ring 13 or the lower end 25a can be secured to the nut 8, by welding, gluing or making a single piece.
  • the indicating and storage means 12 are attached to the strut 1, to be easily replaced but also to be easily adapted to existing struts without having to change them.
  • the fact of not having to modify existing struts is particularly advantageous when a forestay is a safety organ whose structural changes require a new security check by the competent certification and control bodies.
  • the indication and storage means 12 are only reported on the strut 1 and separable thereof, it is advantageous to provide anti-disengagement means (not visible in the figures) of the slide 3 and the barrel 2. , so that the strut 1 must be disassembled at least partially to separate the slide 3 and the barrel 2.
  • the means of indication and storage 12 can not be removed without a voluntary action of disassembly, action that should usually be done using specific tools.
  • the indication and the memorization of the exceeding of a predetermined axial compression load value is independent of the length L of the extension of the strut 1.
  • the stay 1 comprises means for limiting the penetration (not shown) of the slide 3 in the drum 2, shaped so that the upper end (flange 11) of the slide 3 does not come into contact with the indicating and storage means 12 arranged between the slide 3 and the barrel 2.
  • Figures 1 to 10 illustrate the invention in connection with a strut according to standard NF EN 1065 type covered net
  • the invention applies similarly to struts according to standard NF EN 1065 apparent thread type, props the type of forestay marketed under the name ALUPROP, and more generally to all telescopic props comprising two telescopic tubes with a system for adjusting their length, regardless of their constituent materials.

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Description

La présente invention concerne le domaine des éléments de soutien normalement utilisés comme support vertical temporaire sur des ouvrages de construction, et concerne plus particulièrement les étais à deux tubes télescopiques qui peuvent être déplacés l'un dans l'autre.The present invention relates to the field of support elements normally used as a temporary vertical support on construction works, and more particularly relates to props with two telescopic tubes that can be moved one inside the other.

La norme NF EN 1065 décrit deux types d'étais télescopiques, l'un à filet apparent et l'autre à filet recouvert. Ces étais télescopiques comportent deux tubes télescopiques appelés respectivement fût et coulisse, un système de réglage approximatif à l'aide d'une broche insérée dans des trous de la coulisse, et un système de réglage précis par un écrou.The standard NF EN 1065 describes two types of telescopic props, one with apparent net and the other with covered net. These telescopic props comprise two telescopic tubes called respectively barrel and slide, an approximate adjustment system using a pin inserted into the holes of the slide, and a precise adjustment system by a nut.

Un autre type d'étai connu est un étai en aluminium tel que celui commercialisé sous la dénomination ALUPROP par la société ULMA. Cet étai comporte un fût et une coulisse filetée extérieurement. Le système de réglage de cet étai comporte un écrou coopérant par vissage avec le filetage extérieur de la coulisse et présentant des dimensions extérieures lui permettant de venir en appui contre l'extrémité supérieure du fût. Ce type d'étai peut cependant être réalisé en un autre matériau que de l'aluminium.Another type of known forestay is an aluminum stay such as that marketed under the name ALUPROP by ULMA. This forestay has a shaft and a threaded slide externally. The adjustment system of this strut comprises a nut cooperating by screwing with the external thread of the slide and having external dimensions allowing it to bear against the upper end of the barrel. This type of forestay can however be made of a material other than aluminum.

Lors de son utilisation, un étai est soumis à une charge de compression axiale importante susceptible de provoquer son flambage et qui peut détériorer l'étai si elle est trop élevée. Cette charge de compression peut parfois amener l'étai au-delà de sa valeur limite élastique, c'est-à-dire que l'étai a été déformé plastiquement par un flambage excessif.In use, a forestay is subjected to a significant axial compression load likely to cause buckling and can deteriorate the forestay if it is too high. This compression load can sometimes bring the strut beyond its elastic limit value, that is to say that the strut has been deformed plastically by excessive buckling.

Lorsqu'un étai a été déformé par flambage au-delà de son domaine de comportement élastique, il arrive que cet étai ne puisse pas être replié par coulissement de la coulisse dans le fût. L'anomalie est alors détectée et l'étai mis au rebut ou envoyé en maintenance et vérification. C'est là bien souvent le seul test mis en pratique par les opérateurs.When a strut has been deformed by buckling beyond its range of elastic behavior, it can happen that this strut can not be folded by sliding of the slide in the barrel. The anomaly is then detected and discarded or sent for maintenance and verification. This is often the only test put into practice by operators.

Or, il arrive souvent que les étais connus puissent être repliés normalement par coulissement de la coulisse dans le fût, et ce malgré le fait que ceux-ci aient été contraints et déformés plastiquement de façon permanente. L'opérateur ne détecte alors aucune anomalie. Mais une déformation permanente par flambage, même légère, affaiblit l'étai et réduit sa capacité à supporter ensuite une charge axiale. On doit donc considérer qu'une déformation permanente par flambage est une détérioration de l'étai. Il se présente alors un fort risque d'accident lors d'une utilisation ultérieure de cet étai, accident qui menace généralement la vie de nombreux ouvriers travaillant sur l'ouvrage en construction.However, it often happens that known struts can be folded normally by sliding the slide in the barrel, despite the fact that they have been constrained and plastically deformed permanently. The operator does not detect any anomalies. But a permanent deformation by buckling, even slight, weakens the strut and reduces its ability to bear then an axial load. It must therefore be considered that a permanent deformation by buckling is a deterioration of the forestay. It then presents a high risk of accident during a subsequent use of the forestay, an accident that generally threatens the lives of many workers working on the structure under construction.

Cet inconvénient semble résulter le plus souvent des fortes tolérances admises lors de la fabrication des étais. Mais il n'est pas possible de diminuer ces tolérances car cela pourrait mener à des grippages intempestifs des étais lors des rentrées et sorties successives de la coulisse, et ce malgré l'absence de détérioration.This disadvantage seems to result most often strong tolerances allowed during the manufacture of props. But it is not possible to reduce these tolerances because it could lead to untimely seizure of props during successive re-entry and exit of the slide, despite the absence of deterioration.

Le document GB 844 137 A décrit un étai selon le préambule de la revendication 1. Les moyens d'indication et de mémorisation de cet étai sont disposés sur la semelle supérieure de l'étai, ce qui les expose à un risque important de dégradation fortuite lors de la manutention et de l'utilisation de l'étai. En effet, lors de sa manutention et de son utilisation, un étai est posé sur le sol selon son extrémité inférieure de fût ou selon son extrémité supérieure de coulisse, voire selon les deux, en étant posé brusquement sur le sol. En outre, la finalisation de la mise en place d'un étai comprend généralement une étape d'ajustement lors de laquelle un opérateur vient marteler à coups de masse l'extrémité inférieure du fût et/ou l'extrémité supérieure de la coulisse. Les moyens d'indication et de mémorisation de cet étai sont donc fortement exposés à des chocs pouvant conduire à leur dégradation les rendant hors d'usage ou inaptes à remplir leur fonction de sécurité.The document GB 844 137 A describes a strut according to the preamble of claim 1. The means for indicating and storing this strut are arranged on the upper sole of the strut, which exposes them to a significant risk of fortuitous degradation during handling and handling. the use of the forestay. Indeed, during its handling and use, a forestay is placed on the ground according to its lower barrel end or according to its upper end of the slide, or even both, being placed abruptly on the ground. In addition, the finalization of the establishment of a strut generally comprises an adjustment step in which an operator hammers the mass of the lower end of the barrel and / or the upper end of the slide. The means of indication and storage of this forestay are therefore strongly exposed to shocks that can lead to their degradation making them out of use or unable to fulfill their safety function.

Le document FR 1 015 388 A décrit un étai à moyens de mesure et d'indication d'une charge de compression axiale supportée par l'étai. Ces moyens de mesure et d'indication ne sont pas fiables car la valeur de la charge qui sera indiquée est fonction de la longueur totale de l'étai qui peut être plus ou moins déployé selon le besoin en utilisation. En outre, les moyens de mesure et d'indication sont expressément prévus pour être réversibles de façon à reprendre un état d'indication initial lorsque la charge appliquée sur l'étai cesse. Il est ainsi impossible de savoir avec certitude, après utilisation, si l'étai a subi ou non une compression axiale trop forte lors de son utilisation et susceptible d'avoir irrémédiablement endommagé sa structure. Un étai endommagé, mais ne présentant aucune anomalie visuellement détectable, pourra ainsi être réutilisé ultérieurement et mettre en grave péril les opérateurs d'un chantier.The document FR 1 015 388 A discloses a strut with means for measuring and indicating an axial compression load supported by the strut. These means of measurement and indication are not reliable because the value of the load that will be indicated is a function of the total length of the forestay which can be more or less deployed according to the need for use. In addition, the measuring and indicating means are expressly provided to be reversible so as to resume an initial indication state when the load applied to the stay ceases. It is thus impossible to know with certainty, after use, whether the strut has undergone or not excessive axial compression during its use and may have irreparably damaged its structure. A forestay damaged, but having no visually detectable anomaly, can thus be reused later and put in danger the operators of a building site.

Un problème proposé par la présente invention est de concevoir un étai dont la détérioration éventuelle peut être repérée aisément par tout opérateur à l'aide de moyens d'indication correctement protégés contre les dégradations et les fonctionnements intempestifs.A problem proposed by the present invention is to design a strut whose possible deterioration can be easily identified by any operator using means of indication properly protected against damage and unwanted operation.

Selon un autre aspect, l'invention vise à concevoir un étai dont la détérioration éventuelle est signalée de façon fiable, inaltérable, irréversible et définitive pour éviter tout risque de fraude et de maladresse, et ce quelle que soit la longueur d'utilisation de l'étai.In another aspect, the invention aims to design a forestay whose possible deterioration is reliably, unalterable, irreversible and definitive to avoid any risk of fraud and clumsiness, regardless of the length of use of the forestay.

Pour atteindre ces objets, ainsi que d'autres, la présente invention propose un étai selon la revendication 1.To achieve these and other objects, the present invention provides a strut according to claim 1.

En choisissant une valeur de charge de compression axiale prédéterminée (par des essais, par l'expérience ou par calcul) au-delà de laquelle on sait que l'étai risque de présenter une détérioration inadmissible, les moyens d'indication et de mémorisation permettent à l'opérateur de mettre l'étai au rebut, ou de le mettre de côté pour le soumettre à une vérification ou à une maintenance. La valeur de charge de compression axiale prédéterminée pourra être inférieure ou égale à la charge limite théorique provoquant une déformation plastique de l'étai.By choosing a predetermined axial compression load value (by tests, by experiment or by calculation) beyond which it is known that the strut may present an inadmissible deterioration, the means of indication and memorization allow the operator to discard the forestay, or set it aside for verification or maintenance. The predetermined axial compression load value may be less than or equal to the theoretical limit load causing plastic deformation of the strut.

Les opérateurs peuvent se maintenir à distance du danger lorsque les moyens d'indication et de mémorisation indiquent un dépassement de la valeur de charge de compression axiale prédéterminée lors de l'utilisation de l'étai.Operators can keep clear of the danger when the indicating and storing means indicate an exceeding of the predetermined axial compression load value when using the strut.

Les moyens d'indication et de mémorisation permettent également d'indiquer en sécurité et après l'utilisation de l'étai, tout dépassement éventuel de la valeur de charge de compression axiale prédéterminée qui s'est produit pendant l'utilisation de l'étai, ce dépassement ayant été mémorisé. Cela permet aux opérateurs de ne pas réutiliser l'étai une nouvelle fois mais plutôt de le mettre au rebut ou de le mettre de côté pour le soumettre à une vérification ou à une maintenance.The indicating and memorizing means also make it possible to indicate safely and after the use of the strut, any exceeding of the predetermined axial compression load value which has occurred during the use of the strut. , this overshoot having been memorized. This allows operators not to reuse the forestay again but rather to scrap it or put it aside for verification or maintenance.

Pour ce faire, les moyens d'indication et de mémorisation sont adaptés pour être déformés de façon permanente dès que la charge de compression axiale dépasse ladite valeur de charge de compression axiale prédéterminée.For this purpose, the indicating and memorizing means are adapted to be deformed permanently as soon as the axial compression load exceeds said predetermined axial compression load value.

Une déformation permanente est un moyen simple et efficace de mémorisation rendant très difficiles, voire quasiment impossibles, les fraudes ou maladresses involontaires dans la matérialisation (indication et mémorisation) du dépassement de la valeur de charge de compression axiale prédéterminée.A permanent deformation is a simple and effective means of memorization making it very difficult, even almost impossible, unintentional fraud or awkwardness in the materialization (indication and storage) of exceeding the predetermined axial compression load value.

Les moyens d'indication et de mémorisation sont conformés de façon à être disposés au moins en partie entre la coulisse et le fût, pour reprendre la charge de compression axiale appliquée à l'étai.The indicating and memorizing means are shaped so as to be arranged at least partly between the slide and the barrel, to take up the axial compression load applied to the strut.

Les moyens d'indication et de mémorisation sont ainsi disposés dans une zone qui est moins exposée aux chocs lors de la manutention et de l'utilisation des étais que l'extrémité inférieure du fût ou que l'extrémité supérieure de la coulisse.The indication and storage means are thus arranged in an area which is less exposed to shocks during the handling and use of props than the lower end of the barrel or the upper end of the slide.

Avantageusement, l'étai peut comporter des moyens de limitation de la pénétration de la coulisse dans le fût, conformés de telle sorte que, en position de repli maximum de l'étai, l'extrémité supérieure de la coulisse ne vient pas en contact avec les moyens d'indication et de mémorisation disposés entre la coulisse et le fût.Advantageously, the strut may comprise means for limiting the penetration of the slide into the barrel, shaped so that, in the maximum retracted position of the strut, the upper end of the slide does not come into contact with the strut. the indicating and memorizing means arranged between the slide and the barrel.

On protège ainsi les moyens d'indication et de mémorisation contre un coulissement trop important de la coulisse dans le fût, coulissement qui pourrait provoquer en fin de coulissement l'application d'un choc dynamique susceptible de détériorer les moyens d'indication et de mémorisation.This protects the indicating and memorizing means against excessive sliding of the slide in the barrel, which sliding could cause at the end of sliding the application of a dynamic shock likely to deteriorate the means of indication and storage .

Dans une première variante de l'invention, les moyens d'indication et de mémorisation peuvent être solidaires de l'étai. Les moyens d'indication et de mémorisation sont ainsi inséparables de l'étai et donc imperdables.In a first variant of the invention, the indication and storage means may be integral with the strut. The means of indication and storage are thus inseparable from the strut and therefore captive.

Dans une deuxième variante de l'invention, les moyens d'indication et de mémorisation peuvent être rapportés sur l'étai. Les moyens d'indication et de mémorisation peuvent ainsi être facilement remplacés dans le cas où, bien qu'un dépassement de la valeur de charge de compression axiale prédéterminée se soit produit, l'étai ne présente après vérification aucune détérioration susceptible de mettre en danger la vie des opérateurs. En outre, des moyens d'indication et de mémorisation rapportés peuvent être adaptés sur des étais existants sans avoir à modifier ces derniers.In a second variant of the invention, the indication and storage means can be reported on the forestay. The indicating and memorizing means can thus be easily replaced in the case where, although the predetermined axial compression load value has been exceeded, the strut does not show, after verification, any deterioration liable to be endangered. the life of the operators. In addition, reporting and storage means reported can be adapted on existing struts without having to modify them.

Dans le cas de la deuxième variante, l'étai comporte avantageusement des moyens anti-déboîtement de la coulisse et du fût, de telle sorte que l'étai doit être démonté au moins partiellement afin de séparer la coulisse et le fût. Les moyens d'indication et de mémorisation ne peuvent ainsi pas être retirés sans une action volontaire de démontage, qui s'effectue le plus souvent à l'aide d'un outillage spécifique.In the case of the second variant, the strut advantageously comprises anti-disengagement means of the slide and the barrel, so that the strut must be disassembled at least partially to separate the slide and the barrel. The means of indication and storage can not be removed without a voluntary action of disassembly, which is usually done using a specific tool.

De préférence, les moyens d'indication et de mémorisation peuvent se présenter sensiblement sous la forme d'une couronne de diamètre intérieur adapté pour recevoir à coulissement la coulisse de l'étai.Preferably, the indication and storage means may be substantially in the form of a ring of internal diameter adapted to slidably receive the slide of the strut.

Les moyens d'indication et de mémorisation peuvent ainsi être perçus depuis n'importe quelle direction à l'écart de l'étai qui n'a, par conséquent, pas à être orienté de façon particulière par les opérateurs lors de son installation. La forme de couronne permet en outre un montage rapide par simple engagement autour de la coulisse.The means of indication and storage can thus be perceived from any direction away from the strut which therefore does not have to be oriented in a particular way by the operators during its installation. The crown shape also allows quick assembly by simple engagement around the slide.

Dans un premier mode de réalisation de l'invention, la déformation permanente peut être une déformation plastique. Ce mode de déformation permet non seulement de mémoriser de façon irréversible le dépassement de la valeur de charge de compression axiale prédéterminée, mais permet également de mémoriser la valeur de charge de compression maximale à laquelle l'étai a été soumis. On peut ainsi mieux détecter et analyser les défauts d'utilisation par les opérateurs et donc les causes d'éventuels accidents.In a first embodiment of the invention, the permanent deformation may be a plastic deformation. This mode of deformation not only makes it possible to memorize irreversibly the exceeding of the value of predetermined axial compression load, but also allows to memorize the maximum compressive load value to which the strut has been subjected. It is thus possible to better detect and analyze the defects of use by the operators and thus the causes of possible accidents.

Avantageusement, on peut prévoir que :

  • les moyens d'indication et de mémorisation comprennent un anneau inférieur et un anneau supérieur reliés l'un à l'autre par des tiges réparties uniformément selon le périmètre des anneaux inférieur et supérieur,
  • lorsque l'étai est soumis à une charge de compression axiale supérieure à la valeur de charge de compression axiale prédéterminée, les tiges se déforment de façon plastique par flambage de telle sorte que les anneaux se rapprochent l'un de l'autre.
Advantageously, it can be provided that:
  • the indicating and memorizing means comprise a lower ring and an upper ring connected to each other by rods distributed uniformly along the perimeter of the lower and upper rings,
  • when the stay is subjected to an axial compression load greater than the predetermined axial compression load value, the rods deform plastically by buckling so that the rings come closer to each other.

L'ensemble des tiges présente un flambage plastique débutant à partir de la valeur de charge de compression axiale prédéterminée. Cette valeur de charge pourra être fixée et prédéterminée par des calculs et/ou des essais. Ainsi, tout rapprochement irréversible des anneaux supérieur et inférieur, aisément détectable par une simple mesure, signalera un dépassement de la charge de compression axiale prédéterminée et donc un risque potentiel.The set of rods has a plastic buckling starting from the predetermined axial compression load value. This load value can be fixed and predetermined by calculations and / or tests. Thus, any irreversible rapprochement of the upper and lower rings, easily detectable by a single measurement, will signal an exceeding of the predetermined axial compression load and therefore a potential risk.

En alternative, on peut prévoir que :

  • les moyens d'indication et de mémorisation comprennent un manchon destiné à entourer la coulisse sur une partie de sa longueur,
  • le manchon comporte une extrémité inférieure destinée à reposer sur le fût,
  • le manchon comporte une face supérieure de support destinée à reprendre la charge de compression axiale appliquée à l'étai,
  • lorsque l'étai est soumis à une charge de compression axiale supérieure à la valeur de charge de compression axiale prédéterminée, le manchon se déforme de façon plastique de telle sorte que la face supérieure de support et l'extrémité inférieure du manchon se rapprochent l'une de l'autre.
Alternatively, it can be expected that:
  • the indicating and memorizing means comprise a sleeve intended to surround the slide on part of its length,
  • the sleeve has a lower end intended to rest on the barrel,
  • the sleeve comprises an upper support face intended to take up the axial compression load applied to the strut,
  • when the strut is subjected to an axial compression load greater than the predetermined axial compression load value, the sleeve deforms plastically so that the upper support face and the lower end of the sleeve are brought closer together; one of the other.

Le manchon présente une déformation plastique débutant à partir de la valeur de charge de compression axiale prédéterminée. Cette valeur de charge pourra être fixée et prédéterminée par des calculs et/ou des essais. Ainsi, tout rapprochement irréversible de la face supérieure de support et de l'extrémité inférieure du manchon, aisément détectable par une simple mesure, signalera un dépassement de la charge de compression axiale prédéterminée et donc un risque potentiel.The sleeve has a plastic deformation starting from the predetermined axial compression load value. This load value can be fixed and predetermined by calculations and / or tests. Thus, any irreversible approximation of the upper support surface and the lower end of the sleeve, easily detectable by a single measurement, will signal an overshoot of the predetermined axial compression load and therefore a potential risk.

De préférence, on peut prévoir que :

  • le manchon comporte au moins une lumière destinée à recevoir une broche permettant d'empêcher la coulisse de coulisser dans le fût,
  • lorsque l'étai est soumis à une charge de compression axiale supérieure à la valeur de charge de compression axiale prédéterminée, la lumière se déforme et s'allonge selon une direction sous l'effet de la charge de compression axiale.
Preferably, it can be provided that:
  • the sleeve has at least one slot for receiving a pin to prevent the slide from sliding in the barrel,
  • when the strut is subjected to an axial compression load greater than the predetermined axial compression load value, the light deforms and extends in one direction under the effect of the axial compression load.

La déformation oblongue de la lumière sous l'effet de la charge de compression axiale permet une lecture simple et rapide de ce que la valeur de la charge de compression axiale prédéterminée a été dépassée.The oblong deformation of the light under the effect of the axial compression load allows a simple and fast reading that the value of the predetermined axial compression load has been exceeded.

Afin de faciliter la perception visuelle d'une déformation plastique, on peut prévoir un code couleur et/ou une échelle graduée.In order to facilitate the visual perception of a plastic deformation, it is possible to provide a color code and / or a graduated scale.

Dans un deuxième mode de réalisation de l'invention, la déformation permanente peut être une rupture. Ce mode de déformation est simple à percevoir visuellement et à interpréter. Il indique le dépassement de la valeur de charge de compression axiale prédéterminée de façon indubitable et irréversible.In a second embodiment of the invention, the permanent deformation can be a break. This mode of deformation is simple to perceive visually and to interpret. It indicates the exceeding of the predetermined axial compression load value unmistakably and irreversibly.

Avantageusement, les moyens d'indication et de mémorisation peuvent comprendre une capsule de liquide coloré destinée être rompue lorsque la charge de compression axiale appliquée sur l'étai dépasse la valeur de la charge de compression axiale prédéterminée, les moyens d'indication et de mémorisation étant conformés de telle sorte que, après rupture, le liquide coloré peut s'écouler hors de la capsule et être perçu visuellement par un opérateur.Advantageously, the indicating and memorizing means may comprise a colored liquid capsule to be broken when the axial compression load applied on the strut exceeds the value of the predetermined axial compression load, the indication and storage means. being shaped such that, after rupture, the colored liquid may flow out of the capsule and be perceived visually by an operator.

Le liquide peut aisément être détecté à distance par l'opérateur et peut en outre se répandre sur l'étai pour le marquer, de préférence de façon indélébile.The liquid can easily be detected remotely by the operator and may further spread on the strut to mark it, preferably indelibly.

De préférence, les moyens d'indication et de mémorisation peuvent comprendre au moins un anneau destiné à se rompre lorsque la charge de compression axiale appliquée sur l'étai dépasse la valeur de charge de compression axiale prédéterminée.Preferably, the indicating and storing means may comprise at least one ring intended to break when the axial compressive load applied to the strut exceeds the predetermined axial compression load value.

La rupture de l'anneau, voire sa perte suite à sa rupture, signale de façon claire et évidente le risque à l'opérateur.The rupture of the ring, or even its loss following its rupture, clearly and obviously indicates the risk to the operator.

D'autres objets, caractéristiques et avantages de la présente invention ressortiront de la description suivante de modes de réalisation particuliers, faite en relation avec les figures jointes, parmi lesquelles :

  • la figure 1 est une vue de face d'une première variante d'un premier mode de réalisation d'étai selon l'invention ;
  • la figure 2 est une vue partielle en coupe diamétrale de l'étai de la figure 1 ;
  • la figure 3 est une vue en perspective et en coupe de moyens d'indication et de mémorisation utilisés dans l'étai des figures 1 et 2 ;
  • la figure 4 est une vue partielle en coupe diamétrale de l'étai des figures 1 et 2 après application d'une charge de compression axiale supérieure à la valeur de charge de compression axiale prédéterminée ;
  • la figure 5 est une vue partielle en coupe diamétrale d'une première variante d'un deuxième mode de réalisation d'étai selon l'invention ;
  • la figure 6 est une vue partielle en coupe diamétrale d'une deuxième variante du deuxième mode de réalisation d'étai selon l'invention ;
  • la figure 7 est une vue partielle en coupe diamétrale d'une troisième variante du deuxième mode de réalisation d'étai selon l'invention ;
  • la figure 8 est une vue partielle en coupe diamétrale d'une deuxième variante du premier mode de réalisation d'étai selon l'invention ;
  • la figure 9 est une vue en perspective des moyens d'indication et de mémorisation utilisés dans l'étai de la figure 8 ; et
  • la figure 10 est une vue de côté des moyens d'indication et de mémorisation des figures 8 et 9 après application d'une charge de compression axiale supérieure à la valeur de charge de compression axiale prédéterminée.
Other objects, features and advantages of the present invention will become apparent from the following description of particular embodiments, with reference to the accompanying figures, in which:
  • the figure 1 is a front view of a first variant of a first embodiment of forestay according to the invention;
  • the figure 2 is a partial view in diametrical section of the forestay figure 1 ;
  • the figure 3 is a perspective view in section of indicating and storage means used in the strut of figures 1 and 2 ;
  • the figure 4 is a partial view in diametrical section of the forestay figures 1 and 2 after applying an axial compression load greater than the predetermined axial compression load value;
  • the figure 5 is a partial view in diametral section of a first variant of a second embodiment of forestay according to the invention;
  • the figure 6 is a partial view in diametral section of a second variant of the second embodiment of forestay according to the invention;
  • the figure 7 is a partial view in diametral section of a third variant of the second embodiment of forestay according to the invention;
  • the figure 8 is a partial view in diametral section of a second variant of the first embodiment of forestay according to the invention;
  • the figure 9 is a perspective view of the indicating and memorizing means used in the strut of the figure 8 ; and
  • the figure 10 is a side view of the means for indicating and memorizing the figures 8 and 9 after applying an axial compression load greater than the predetermined axial compression load value.

Sur les figures 1, 2 et 4 à 8 est illustré un étai 1 télescopique, comportant deux tubes télescopiques, à savoir un fût 2 et une coulisse 3, la coulisse 3 étant montée à coulissement dans le fût 2. La coulisse 3 et le fût 2 coopèrent par coulissement au moyen de portions respectives 300 et 200 cylindriques. L'étai 1 comporte un système de réglage approximatif 4 à l'aide d'une broche 5 que l'on insère dans l'un des trous 6 de la coulisse 3 en fonction de la longueur désirée. L'étai 1 comporte en outre un système de réglage précis 7 par un écrou 8. On peut ainsi ajuster parfaitement la longueur L de déploiement de l'étai 1 en fonction de l'utilisation projetée.On the Figures 1, 2 and 4 to 8 is illustrated a telescopic strut 1, comprising two telescopic tubes, namely a barrel 2 and a slide 3, the slide 3 being slidably mounted in the barrel 2. The slide 3 and the barrel 2 cooperate by sliding by means of respective portions 300 and 200 cylindrical. The strut 1 comprises an approximate adjustment system 4 with a pin 5 which is inserted into one of the holes 6 of the slide 3 according to the desired length. The strut 1 further comprises a precise adjustment system 7 by a nut 8. It can thus perfectly adjust the length L of deployment of the strut 1 according to the intended use.

L'écrou 8 recouvre le filetage externe 9 prévu à l'extrémité supérieure 2a du fût 2. L'étai des figures 1, 2 et 4 à 8 est ainsi du type à filet recouvert selon la norme NF EN 1065.The nut 8 covers the external thread 9 provided at the upper end 2a of the barrel 2. Figures 1, 2 and 4 to 8 is thus of the type covered net according to standard NF EN 1065.

L'étai 1 est adapté pour soutenir une charge de compression axiale au moyen de deux semelles 10 et 11 (figure 1). La semelle 10, portée par le fût 2, est destinée à venir en appui sur le sol tandis que la semelle 11, portée par la coulisse 3, est destinée à venir en appui direct ou indirect contre l'ouvrage en construction à soutenir.The strut 1 is adapted to support an axial compressive load by means of two flanges 10 and 11 ( figure 1 ). The sole 10, carried by the shaft 2, is intended to rest on the ground while the sole 11, carried by the slide 3, is intended to bear directly or indirectly against the structure under construction to support.

Le réglage de la longueur totale de l'étai 1 s'effectue tout d'abord avec le système de réglage approximatif 4 : la coulisse 3 est sortie hors du fût 2 jusqu'à la longueur approximative désirée, puis la broche 5 est engagée dans le trou 6 apparent et situé au plus près de l'extrémité supérieure 2a du fût 2.The adjustment of the total length of the strut 1 is effected first with the approximate adjustment system 4: the slider 3 is taken out of the drum 2 to the desired approximate length, then the spindle 5 is engaged in the apparent hole 6 and located closer to the upper end 2a of the barrel 2.

Le réglage en longueur de l'étai 1 est ensuite achevé par l'utilisation du système de réglage précis 7 en faisant tourner l'écrou 8 à l'aide de ses poignées 8a et 8b.The length adjustment of the strut 1 is then completed by using the precise adjustment system 7 by rotating the nut 8 with its handles 8a and 8b.

Lors de son utilisation, l'étai 1 supporte une charge de compression axiale C correspondant à une partie au moins du poids d'un ouvrage en construction.In use, the strut 1 supports an axial compression load C corresponding to at least part of the weight of a structure under construction.

Sur les figures 1, 2 et 4 à 8, l'étai 1 comporte des moyens d'indication et de mémorisation 12 d'un dépassement de la charge de compression axiale au-delà d'une valeur de charge de compression axiale prédéterminée. Les moyens d'indication et de mémorisation 12 permettent de signaler de façon fiable et inaltérable le fait que la charge de compression axiale a dépassé la valeur de charge de compression axiale prédéterminée risquant d'induire une détérioration de l'étai et donc d'induire un danger pour les opérateurs.On the Figures 1, 2 and 4 to 8 , strut 1 comprises means for indicating and storing 12 an overshoot of the axial compression load beyond a predetermined axial compression load value. The indicating and memorizing means 12 make it possible to report in a reliable and unalterable manner the fact that the axial compression load has exceeded the predetermined axial compression load value, which risks inducing a deterioration of the strut and therefore of inducing a danger for the operators.

Sur les figures 1, 2 et 4 à 8, on voit que les moyens d'indication et de mémorisation 12 sont conformés de façon à être disposés entre la coulisse 3 et le fût 2 pour reprendre la charge de compression axiale C appliquée à l'étai 1. En pratique, les moyens d'indication et de mémorisation 12 se présentent alors sensiblement sous la forme d'une couronne de diamètre intérieur D1 adaptée pour recevoir à coulissement la coulisse 3 de l'étai 1 qui présente un diamètre extérieur D2 inférieur au diamètre intérieur D1. Les moyens d'indication et de mémorisation 12 sont plus particulièrement intercalés entre l'écrou 8 et la broche 5, donc entre le fût 2 et la coulisse 3.On the Figures 1, 2 and 4 to 8 it can be seen that the indicating and memorizing means 12 are shaped so as to be arranged between the slide 3 and the barrel 2 to take up the axial compression load C applied to the strut 1. In practice, the means of indication and storage 12 are then substantially in the form of a ring of internal diameter D1 adapted to slidably receive the slide 3 of the strut 1 which has an outer diameter D2 smaller than the inner diameter D1. The indicating and memorizing means 12 are more particularly interposed between the nut 8 and the pin 5, thus between the barrel 2 and the slide 3.

Afin de matérialiser (c'est-à-dire indiquer et garder en mémoire) un dépassement de la valeur de charge de compression axiale prédéterminée, les moyens d'indication et de mémorisation 12 sont adaptés pour être déformés de façon permanente lorsque la charge de compression axiale subie par l'étai est supérieure à ladite valeur de charge de compression axiale prédéterminée.In order to materialize (i.e., indicate and keep in memory) an overshoot of the predetermined axial compression load value, the indicating and memorizing means 12 are adapted to be permanently deformed when the load of axial compression experienced by the strut is greater than said predetermined axial compression load value.

Dans un premier mode de réalisation avantageux illustré sur les figures 1 à 4, la déformation permanente est une déformation plastique.In a first advantageous embodiment illustrated in the Figures 1 to 4 permanent deformation is a plastic deformation.

Pour ce faire, on voit plus particulièrement sur les figures 2 à 4 illustrant une première variante que les moyens d'indication et de mémorisation 12 comprennent un anneau inférieur 13 et un anneau supérieur 14 reliés l'un à l'autre par des tiges 15 uniformément réparties selon le périmètre des anneaux inférieur 13 et supérieur 14.To do this, we see more particularly the Figures 2 to 4 illustrating a first variant that the indicating and memorizing means 12 comprise a lower ring 13 and an upper ring 14 connected to one another by rods 15 uniformly distributed along the perimeter of the lower and upper rings 13 and 14.

L'ensemble constitué par la pluralité de tiges 15 présente des caractéristiques et un comportement en compression prédéterminé et connu, par exemple par des calculs ou par la réalisation d'essais.The assembly constituted by the plurality of rods 15 has characteristics and a behavior in predetermined and known compression, for example by calculations or by carrying out tests.

Avant déformation des moyens d'indication et de mémorisation 12, l'étai 1 se trouve tel qu'illustré sur les figures 1 et 2. Les tiges 15 maintiennent les anneaux inférieur 13 et supérieur 14 à une distance d1, et ce tant que la charge de compression axiale C ne dépasse pas la valeur de charge de compression axiale prédéterminée entraînant la déformation des moyens d'indication et de mémorisation 12.Before deformation of the indicating and memorizing means 12, the strut 1 is as illustrated on the figures 1 and 2 . The rods 15 hold the lower 13 and upper 14 rings at a distance d1, as long as the axial compression load C does not exceed the predetermined axial compression load value causing the deformation of the indicating and memorizing means 12.

Si l'étai 1 est soumis lors de son utilisation à une charge C supérieure à la valeur de la charge de compression axiale prédéterminée, les moyens d'indication et de mémorisation 12 se déforment. En l'espèce, les tiges 15 se déforment de façon plastique par flambage comme illustré sur la figure 4, de telle sorte que les anneaux inférieur 13 et supérieur 14 se rapprochent l'un de l'autre. Les anneaux inférieur 13 et supérieur 14 sont alors distants d'une distance d2 inférieure à la distance d1. Les tiges 15 ayant été déformées plastiquement, la distance d2 séparant les anneaux 13 et 14 est conservée après utilisation de l'étai 1 qui n'est alors plus soumis à une charge de compression axiale. La mesure de la distance d2 permet d'estimer la charge de compression axiale qu'a enduré l'étai 1.If the strut 1 is subjected during its use to a load C greater than the value of the predetermined axial compression load, the indicating and memorizing means 12 are deformed. In this case, the rods 15 deform plastically by buckling as illustrated in FIG. figure 4 , so that the lower 13 and upper 14 rings are closer to each other. The lower 13 and upper 14 rings are then distant by a distance d2 less than the distance d1. The rods 15 having been plastically deformed, the distance d2 between the rings 13 and 14 is retained after use of the strut 1 which is then no longer subjected to an axial compression load. The measurement of the distance d2 makes it possible to estimate the axial compressive load that the strut 1 has endured.

Dans le mode de réalisation illustré sur les figures 1 à 4, l'anneau inférieur 13 est solidaire d'un manchon cylindrique extérieur 16 recevant à coulissement un manchon cylindrique intérieur 17 tenu par l'anneau supérieur 14. Les manchons 16 et 17 permettent de protéger les tiges 15 contre des chocs accidentels radiaux.In the embodiment illustrated on the Figures 1 to 4 , the lower ring 13 is secured to an outer cylindrical sleeve 16 slidably receiving an inner cylindrical sleeve 17 held by the upper ring 14. The sleeves 16 and 17 can protect the rods 15 against accidental radial shocks.

Afin de percevoir rapidement et facilement la déformation des moyens d'indication et de mémorisation 12, le manchon cylindrique extérieur 16 comporte des lumières 16a et 16b, tandis que le manchon cylindrique intérieur 17 comporte un code couleur et/ou une échelle graduée 17a apparents à travers les lumières 16a et 16b.In order to quickly and easily perceive the deformation of the indicating and memorizing means 12, the outer cylindrical sleeve 16 comprises slots 16a and 16b, while the inner cylindrical sleeve 17 has a color code and / or a graduated scale 17a apparent to through the lights 16a and 16b.

Dans une deuxième variante illustrée sur les figures 8 à 10, les moyens d'indication et de mémorisation 12 comprennent un manchon 25 destiné à entourer la coulisse 3 sur une partie de sa longueur. Le manchon 25 comporte une extrémité inférieure 25a destinée à reposer sur le fût 2. Le manchon 25 comporte également une face supérieure de support 25b destinée à reprendre la charge de compression axiale C appliquée à l'étai 1. En pratique, la face supérieure de support 25b de support reçoit la broche 5 en appui. Le manchon 25 est ainsi intercalé entre l'écrou 8 du fût 2 et la broche 5 maintenant la coulisse 3.In a second variant illustrated on the Figures 8 to 10 , the indicating and memorizing means 12 comprise a sleeve 25 intended to surround the slide 3 over part of its length. The sleeve 25 has a lower end 25a intended to rest on the barrel 2. The sleeve 25 also comprises a support upper face 25b intended to take up the axial compression load C applied to the strut 1. In practice, the upper face of Support support 25b receives pin 5 in support. The sleeve 25 is thus interposed between the nut 8 of the barrel 2 and the pin 5 holding the slide 3.

Lorsque l'étai 1 est soumis à une charge de compression axiale C supérieure à la valeur de charge de compression axiale prédéterminée, le manchon 25 se déforme de façon plastique de telle sorte que la face supérieure de support 25b et l'extrémité inférieure 25a du manchon 25 se rapprochent l'une de l'autre.When the strut 1 is subjected to an axial compression load C greater than the predetermined axial compression load value, the The sleeve 25 is plastically deformed so that the upper support face 25b and the lower end 25a of the sleeve 25 come closer to each other.

Les moyens d'indication et de mémorisation 12 de la figure 8 sont plus particulièrement illustrés sur la figure 9. Sur cette figure, le manchon 25 comporte deux lumières 26 et 27 destinées à recevoir la broche 5 pour empêcher la coulisse 3 de coulisser dans le fût 2. Lorsque l'étai 1 est soumis à une charge de compression axiale C supérieure à la valeur de charge de compression axiale prédéterminée, les lumières 26 et 27 se déforment et s'allongent selon la direction axiale I-I qui coïncide avec la direction d'application de la charge de compression axiale C.The means of indicating and memorizing 12 of the figure 8 are particularly illustrated on the figure 9 . In this figure, the sleeve 25 has two slots 26 and 27 for receiving the pin 5 to prevent the slide 3 from sliding in the barrel 2. When the strut 1 is subjected to an axial compression load C greater than the value of predetermined axial compression load, the lights 26 and 27 are deformed and elongate in the axial direction II which coincides with the direction of application of the axial compression load C.

La partie du manchon 25 destinée à se déformer de façon plastique est comprise entre la face supérieure de support 25b et l'extrémité inférieure 25a.The portion of the sleeve 25 for plastically deforming is between the upper support surface 25b and the lower end 25a.

Sur la figure 10 est illustré le manchon 25 de la figure 9 après déformation due à un dépassement de la valeur de charge de compression axiale prédéterminée. On voit que la lumière 26, initialement de forme circulaire (figure 9), présente désormais une forme oblongue s'allongeant selon la direction I-I. La face supérieure de support 25b et l'extrémité inférieure 25a se sont ainsi rapprochées l'une de l'autre sous l'effet de la charge de compression axiale C.On the figure 10 is illustrated the sleeve 25 of the figure 9 after deformation due to exceeding the predetermined axial compression load value. We see that the light 26, initially circular ( figure 9 ), now has an elongated shape extending along the direction II. The upper support face 25b and the lower end 25a are thus brought closer to one another under the effect of the axial compression load C.

Afin de percevoir rapidement et facilement la déformation des moyens d'indication et de mémorisation 12, le manchon 25 présente une ligne de marquage 28. Lorsque la face supérieure de support 25b se trouve en dessous de la ligne de marquage 28, cela signifie que les lumières 26 et 27 se sont déformées sous l'effet de la charge de compression axiale C qui a dépassé la valeur de charge de compression axiale prédéterminée. La ligne de marquage 28 a ainsi un rôle de graduation. Plusieurs lignes de marquage 28 sont envisageables.In order to quickly and easily perceive the deformation of the indicating and memorizing means 12, the sleeve 25 has a marking line 28. When the upper support face 25b is below the marking line 28, this means that the lights 26 and 27 were deformed under the effect of the axial compression load C which exceeded the predetermined axial compression load value. The marking line 28 thus has a graduation role. Several marking lines 28 are conceivable.

Dans un second mode de réalisation de l'invention, illustré plus particulièrement sur les figures 5 à 7, la déformation permanente des moyens d'indication et de mémorisation 12 est une rupture.In a second embodiment of the invention, illustrated more particularly on the Figures 5 to 7 the permanent deformation of the indicating and memorizing means 12 is a rupture.

Dans une première variante illustrée sur la figure 5, les moyens d'indication et de mémorisation 12 comprennent une capsule 18 de liquide coloré destinée à être rompue lorsque la charge de compression axiale C appliquée sur l'étai 1 dépasse la valeur de la charge de compression axiale prédéterminée.In a first variant illustrated on the figure 5 , the indicating and storage means 12 comprise a colored liquid capsule 18 to be broken when the axial compression load C applied on the strut 1 exceeds the value of the predetermined axial compression load.

En l'espèce, les moyens d'indication et de mémorisation 12 comportent une bague inférieure de support 19 destinée à venir au contact de l'écrou 8 et une bague supérieure de support 20 destinée à venir en appui contre la broche 5. Une capsule 18 de liquide coloré est intercalée entre les bagues de support 19 et 20. Lors du dépassement de la valeur de charge de compression axiale prédéterminée, la bague supérieure de support 20 vient au contact de la bague inférieure de support 19 en rompant la capsule 18 de liquide coloré qui s'écoule alors hors de la capsule 18 et hors des moyens d'indication et de mémorisation 12 par des canaux 21 prévus à cet effet. Le liquide coloré peut alors être perçu visuellement par un opérateur qui est alors averti du risque.In this case, the indication and storage means 12 comprise a lower support ring 19 intended to come into contact with the nut 8 and an upper support ring 20 intended to bear against the pin 5. A capsule 18 of colored liquid is interposed between the support rings 19 and 20. When exceeding the predetermined axial compression load value, the upper support ring 20 comes into contact with the lower support ring 19 by breaking the capsule 18 of colored liquid which then flows out of the capsule 18 and out of the indicating and memorizing means 12 by channels 21 provided for this purpose. The colored liquid can then be perceived visually by an operator who is then warned of the risk.

Dans une deuxième variante illustrée sur la figure 6, les moyens d'indication et de mémorisation 12 comprennent un anneau 22 destiné à se rompre lorsque la charge de compression axiale C appliquée sur l'étai 1 dépasse la valeur de charge de compression axiale prédéterminée. L'anneau 22 présente une section transversale S constituée d'un matériau prévu de telle sorte que la section transversale S se rompe lorsque la charge de compression axiale C dépasse la valeur de charge de compression axiale prédéterminée. Un opérateur pourra aisément percevoir visuellement le risque dès lors que l'anneau 22 est rompu et/ou absent.In a second variant illustrated on the figure 6 , the indicating and memorizing means 12 comprise a ring 22 intended to break when the axial compression load C applied on the strut 1 exceeds the predetermined axial compression load value. The ring 22 has a cross section S made of a material provided such that the cross section S breaks when the axial compression load C exceeds the predetermined axial compression load value. An operator can easily perceive the risk visually as soon as the ring 22 is broken and / or absent.

En alternative à la variante illustrée sur la figure 6, on peut prévoir, comme illustré sur la figure 7, des moyens d'indication et de mémorisation 12 comprenant un premier anneau 23 de section transversale sensiblement triangulaire et destiné à reposer sur l'écrou 8, et un deuxième anneau 24 à section transversale triangulaire et destiné à venir au contact de la broche 5. Les anneaux 23 et 24 sont disposés et emboîtés comme illustré sur la figure 7 sur laquelle l'anneau 24 tend à dilater radialement l'anneau 23 sous l'effet de la charge de compression axiale C par un effet de coin.As an alternative to the variant illustrated on the figure 6 , one can predict, as illustrated on the figure 7 , indication and storage means 12 comprising a first ring 23 of substantially triangular cross-section and intended to rest on the nut 8, and a second ring 24 of triangular cross section and intended to come into contact with the pin 5. The rings 23 and 24 are arranged and nested as illustrated on the figure 7 on which the ring 24 tends to expand radially ring 23 under the effect of the axial compression load C by a wedge effect.

Lorsque la charge de compression axiale C dépasse la valeur de charge de compression axiale prédéterminée, l'anneau 23 est dilaté radialement jusqu'à rupture. L'anneau 24 vient alors en contact avec l'écrou 8.When the axial compression load C exceeds the predetermined axial compression load value, the ring 23 is expanded radially to failure. The ring 24 then comes into contact with the nut 8.

La rupture et/ou l'absence de l'anneau 23 peut aisément être perçue visuellement par un opérateur qui est alors averti du risque potentiel.The rupture and / or the absence of the ring 23 can easily be perceived visually by an operator who is then warned of the potential risk.

L'anneau 23 peut présenter une forme de section transversale autre que triangulaire.The ring 23 may have a cross-sectional shape other than triangular.

Il est à noter que, dans l'alternative illustrée sur la figure 7, l'anneau 24 lui-même peut également présenter une rupture lorsque la charge de compression axiale C appliquée sur l'étai dépasse une autre valeur limite de charge de compression axiale prédéterminée, supérieure à la valeur de charge de compression axiale prédéterminée qui conduit l'anneau 23 à se rompre. On dispose ainsi de moyens d'indication et de mémorisation 12 progressifs capables de signaler le dépassement de différentes valeurs de charge de compression axiale prédéterminées.It should be noted that, in the alternative illustrated on the figure 7 the ring 24 itself may also break when the axial compression load C applied on the strut exceeds another predetermined axial compression load limit value, greater than the predetermined axial compression load value which leads to ring 23 to break. This provides progressive indication and storage means 12 capable of to signal the exceeding of different predetermined axial compression load values.

Il est d'ailleurs à noter que plusieurs moyens d'indication et de mémorisation 12, semblables à ceux illustrés sur les figures 1 à 10, peuvent être empilés sur un même étai 1, chacun des moyens d'indication et de mémorisation 12 étant adapté pour être déformé de façon permanente au-delà d'une valeur respective de charge de compression axiale prédéterminée.It should also be noted that several means of indication and memorization 12, similar to those illustrated on the Figures 1 to 10 , can be stacked on the same strut 1, each of the indicating and storage means 12 being adapted to be deformed permanently beyond a respective value of predetermined axial compression load.

Dans chacun des modes de réalisation, variantes et alternatives illustrés sur les figures 1 à 10, on peut prévoir que les moyens d'indication et de mémorisation 12 sont solidaires de l'étai 1, afin d'éviter leur perte ou leur retrait frauduleux. Par exemple, dans le cas des moyens d'indication et de mémorisation 12 illustrés sur les figures 1 à 4 et 8 à 10, l'anneau inférieur 13 ou l'extrémité inférieure 25a peut être rendu solidaire de l'écrou 8, par soudure, collage ou réalisation d'une pièce monobloc.In each of the embodiments, variants and alternatives illustrated on the Figures 1 to 10 , it can be provided that the indicating and storage means 12 are integral with the strut 1, to prevent their loss or fraudulent removal. For example, in the case of indicating and memorizing means 12 illustrated on the Figures 1 to 4 and 8 to 10 , the lower ring 13 or the lower end 25a can be secured to the nut 8, by welding, gluing or making a single piece.

Sur les figures 1 à 10, les moyens d'indication et de mémorisation 12 sont rapportés sur l'étai 1, pour pouvoir être facilement remplacés mais également pour être facilement adaptés sur des étais existants sans avoir à modifier ceux-ci. Le fait de ne pas avoir à modifier les étais existants est particulièrement avantageux dès lors qu'un étai est un organe de sécurité dont toute modification de structure nécessite un nouveau contrôle de sécurité par les organismes de certification et de contrôle compétents.On the Figures 1 to 10 , the indicating and storage means 12 are attached to the strut 1, to be easily replaced but also to be easily adapted to existing struts without having to change them. The fact of not having to modify existing struts is particularly advantageous when a forestay is a safety organ whose structural changes require a new security check by the competent certification and control bodies.

Lorsque les moyens d'indication et de mémorisation 12 sont seulement rapportés sur l'étai 1 et séparables de celui-ci, il est avantageux de prévoir des moyens anti-déboîtement (non visibles sur les figures) de la coulisse 3 et du fût 2, de telle sorte que l'étai 1 doit être démonté au moins partiellement afin de séparer la coulisse 3 et le fût 2. Les moyens d'indication et de mémorisation 12 ne peuvent ainsi pas être retirés sans une action volontaire de démontage, action qui doit le plus souvent s'effectuer à l'aide d'un outillage spécifique.When the indication and storage means 12 are only reported on the strut 1 and separable thereof, it is advantageous to provide anti-disengagement means (not visible in the figures) of the slide 3 and the barrel 2. , so that the strut 1 must be disassembled at least partially to separate the slide 3 and the barrel 2. The means of indication and storage 12 can not be removed without a voluntary action of disassembly, action that should usually be done using specific tools.

Dans tous les modes de réalisation, l'indication et la mémorisation du dépassement d'une valeur de charge de compression axiale prédéterminée est indépendante de la longueur L de déploiement de l'étai 1.In all the embodiments, the indication and the memorization of the exceeding of a predetermined axial compression load value is independent of the length L of the extension of the strut 1.

Sur les figures 1 à 10, il se présente un risque que la semelle 11 vienne heurter les moyens d'indication et de mémorisation 12 lors d'un coulissement d'amplitude excessive de la coulisse 3 dans le fût 2. Il peut alors être appliqué aux moyens d'indication et de mémorisation 12 un choc dynamique susceptible de détériorer ceux-ci. Afin d'éviter ce risque, l'étai 1 comporte des moyens de limitation de la pénétration (non représentés) de la coulisse 3 dans le fût 2, conformés de telle sorte que l'extrémité supérieure (semelle 11) de la coulisse 3 ne vienne pas en contact avec les moyens d'indication et de mémorisation 12 disposés entre la coulisse 3 et le fût 2.On the Figures 1 to 10 , there is a risk that the sole 11 will hit the indicating and storage means 12 during an excessive amplitude sliding of the slide 3 in the barrel 2. It can then be applied to the indication means and memorizing 12 dynamic shock likely to deteriorate them. In order to avoid this risk, the stay 1 comprises means for limiting the penetration (not shown) of the slide 3 in the drum 2, shaped so that the upper end (flange 11) of the slide 3 does not come into contact with the indicating and storage means 12 arranged between the slide 3 and the barrel 2.

En pratique, il suffit de prévoir que, lorsque l'étai est complètement fermé (avec la coulisse 3 engagée au maximum dans le fût 2), l'extrémité supérieure de la coulisse 3 (semelle 11) est distante de l'écrou 8 d'une distance supérieure à la hauteur h des moyens d'indication et de mémorisation 12.In practice, it is sufficient to provide that, when the stay is completely closed (with the slide 3 engaged at most in the barrel 2), the upper end of the slide 3 (sole 11) is distant from the nut 8 a distance greater than the height h of the indicating and memorizing means 12.

Bien que les figures 1 à 10 n'illustrent l'invention qu'en lien avec un étai selon la norme NF EN 1065 de type à filet recouvert, l'invention s'applique de façon analogue aux étais selon la norme NF EN 1065 de type à filet apparent, aux étais du type de l'étai commercialisé sous la dénomination ALUPROP, et de façon plus générale à tous les étais télescopiques comportant deux tubes télescopiques avec un système de réglage de leur longueur, quels que soient leurs matériaux constitutifs.even though Figures 1 to 10 illustrate the invention in connection with a strut according to standard NF EN 1065 type covered net, the invention applies similarly to struts according to standard NF EN 1065 apparent thread type, props the type of forestay marketed under the name ALUPROP, and more generally to all telescopic props comprising two telescopic tubes with a system for adjusting their length, regardless of their constituent materials.

La présente invention n'est pas limitée aux modes de réalisation qui ont été explicitement décrits, mais elle en inclut les diverses variantes et généralisations contenues dans le domaine des revendications ci-après.The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof within the scope of the claims below.

Claims (15)

  1. Prop (1) of adjustable length by means of a slide (3) and a stock (2), and adapted to sustain an axial compression load (C), comprising means for indicating and recording (12) an overshoot of a predetermined axial compression load value, the indication and recording means (12) being adapted to be deformed permanently as soon as the axial compression load (C) exceeds said predetermined axial compression load value, characterised in that the indication and recording means (12) are formed in such a way as to be arranged at least partly between the slide (3) and the stock (2) to take up the axial compression load (C) applied to the prop (1).
  2. Prop (1) according to claim 1, characterised in that it comprises means for limiting the penetration of the slide (3) into the stock (2), formed in such a way that the top end of the slide (3) does not come into contact with the indication and recording means (12).
  3. Prop (1) according to one of claims 1 or 2, characterised in that the indication and recording means (12) are secured to the prop (1).
  4. Prop (1) according to one of claims 1 or 2, characterised in that the indication and recording means (12) are added on to the prop (1).
  5. Prop (1) according to claim 4, characterised in that it comprises means for preventing the slide (3) from leaving the stock (2), such that the prop (1) must be dismantled at least partially in order to separate the slide (3) and the stock (2).
  6. Prop (1) according to any one of claims 1 to 5, characterised in that the indication and recording means (12) take roughly the form of a crown ring of internal diameter adapted to slidingly receive the slide (3) of the prop (1).
  7. Prop (1) according to any one of claims 1 to 6, characterised in that the permanent deformation is a break.
  8. Prop (1) according to claim 7, characterised in that the indication and recording means (12) comprise a capsule (18) of coloured liquid intended to be broken when the axial compression load (C) applied to the prop (1) exceeds the predetermined axial compression load value, the indication and recording means (12) being formed in such a way that, after breakage, the coloured liquid can flow out of the capsule (18) and be perceived visually by an operator.
  9. Prop (1) according to claim 7, characterised in that the indication and recording means (12) comprise at least one ring (22) intended to be broken when the axial compression load (C) applied to the prop (1) exceeds the predetermined axial compression load value.
  10. Prop (1) according to any one of claims 1 to 6, characterised in that the permanent deformation is a plastic deformation.
  11. Prop (1) according to claim 10, characterised in that:
    - the indication and recording means (12) comprise a bottom ring (13) and a top ring (14) linked to one another by rods (15) distributed uniformly along the perimeter of the bottom (13) and top (14) rings,
    - when the prop (1) is subjected to an axial compression load (C) greater than the predetermined axial compression load value, the rods (15) are deformed in a plastic manner by buckling such that the rings (13, 14) approach one another.
  12. Prop (1) according to claim 10, characterised in that:
    - the indication and recording means (12) comprise a sleeve (25) intended to surround the slide (3) over a part of its length,
    - the sleeve (25) comprises a bottom end (25a) intended to rest on the stock (2),
    - the sleeve (25) comprises a supporting top face (25b) intended to take up the axial compression load (C) applied to the prop (1),
    - when the prop (1) is subjected to an axial compression load (C) greater than the predetermined axial compression load value, the sleeve (25) is deformed in a plastic manner such that the supporting top face (25b) and the bottom end (25a) of the sleeve (25) approach one another.
  13. Prop (1) according to claim 12, characterised in that:
    - the sleeve (25) comprises at least one opening (26, 27) intended to receive a pin (5) making it possible to prevent the slide (3) from sliding in the stock (2),
    - when the prop (1) is subjected to an axial compression load (C) greater than the predetermined axial compression load value, the opening (26, 27) is deformed and elongated in a direction (I-I) under the effect of the axial compression load (C).
  14. Prop (1) according to any one of claims 10 to 13, characterised in that the deformation can be read by a colour code and/or by a graduated scale (17a, 28).
  15. Prop (1) according to any one of claims 1 to 14, characterised in that the slide (3) and the stock (2) cooperate by sliding by means of respective cylindrical portions (300, 200).
EP12163678.1A 2011-04-12 2012-04-11 Prop with wear indicating means Active EP2511449B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR1153167A FR2974134B1 (en) 2011-04-12 2011-04-12 ISA MEANS OF INDICATION OF WEAR

Publications (2)

Publication Number Publication Date
EP2511449A1 EP2511449A1 (en) 2012-10-17
EP2511449B1 true EP2511449B1 (en) 2016-04-06

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ID=45929443

Family Applications (1)

Application Number Title Priority Date Filing Date
EP12163678.1A Active EP2511449B1 (en) 2011-04-12 2012-04-11 Prop with wear indicating means

Country Status (2)

Country Link
EP (1) EP2511449B1 (en)
FR (1) FR2974134B1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2636833B2 (en) * 2017-03-15 2018-06-26 Universitat Politècnica De València Load limiter for telescopic work props

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB498676A (en) * 1937-07-08 1939-01-09 Ernest John Egerton Boys Improvements in and relating to pit and like props
FR1015388A (en) * 1947-05-28 1952-09-16 iron prop, for mines
GB844137A (en) * 1957-11-15 1960-08-10 Nicolas Joseph Rutigliano Improvements relating to telescopic props or supports

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FR2974134B1 (en) 2016-02-05
EP2511449A1 (en) 2012-10-17

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