EP1941931B1 - Anchoring device designed to prevent falls - Google Patents

Description

The present invention relates to an anchoring device for an anti-fall connection or a flexible and mobile belay support, such as a cable. The invention more particularly relates to an anchoring device comprising a securing means for forming a fixed anchor point or to cooperate with a flexible anchoring support. In both cases, the securing means essentially undergoes a tensile force.

In the field of fall protection equipment, an anchoring device is a means of prevention used, for example, when working on roofs of buildings, building facades or structures. Such an anchoring device has the function of connecting an individual protection equipment, such as a harness and an anti-fall device, to a fixed structure, while allowing the movement of the speaker on the structure requiring intervention.

Thus, the speaker is connected to a fixed anchor point or to a flexible and mobile belay support, such as a cable or a chain. In the latter case, this construction is generally referred to as "lifeline". In both cases, it is necessary to securely fix the equipment used to the bearing surface by means of an anchoring device. Such an anchoring device thus acts as an interface between the flexible belay support and the bearing surface associated with the structure requiring intervention.

Permanent anchoring devices are known, that is to say permanently fixed, in which a post is generally associated with a base cooperating with fastening elements, such as bolts or pegs, so as to ensure solid and durable attachment of the anchoring device on the carrier surface. The post has the function of raising the cable or chain to avoid harmful contact with the elements of the supporting structure, such as a roof.

The post is dimensioned to withstand shocks resulting from the falls of speakers, so that it does not move or deforms when it undergoes, through the means of securing, a sudden tensile force and important. However, this is detrimental to neighboring anchoring devices, in the case of a lifeline, or fasteners. Indeed, when the anchoring support is well tensioned, it transmits to neighboring anchoring devices considerable reaction forces in the main direction of the anchoring support, that is to say generally perpendicular to the effort of traction undergone. These reaction forces are all the more intense as the anchoring support deforms little, because the component of the forces that the latter transmits to the anchoring devices or to the fastening elements in the main direction of the tensile force is then very weak. Thus, the belay support transmits significant transverse forces that may damage the anchors. Moreover, in the case of a fixed anchor point, the same cause induces the transmission of considerable forces on the fastening elements, such as screws or welds, of the bearing surface.

Otherwise, FR-A-2,883,758 describes a permanent anchoring device comprising a post associated with a bearing surface via a fastening device. The post is surmounted by a post head provided with a tie-down point for a cable. This anchoring device thus ensures effective prevention of falls that could be suffered by those involved in the building. It includes an energy absorbing device capable of reducing the impact that an operator would suffer during a fall. The construction of such an anchoring device is however complex and expensive. Indeed, this anchoring device is composed of a relatively large number of parts, these parts having specific dimensions for their assembly by mutual adjustment. In addition, the implementation of this material requires the cutting of the roof and may cause sealing problems.

In addition, in the event of a fall of a speaker, the flexible belay support suddenly exerts a "shock", that is to say a high and sudden stress, on the anchoring device. When such shock repeats, the structure of the anchoring device, and in particular that of the post, may be weakened. It is then necessary to replace all or part of the anchoring device. Nevertheless, the anchoring devices of the prior art do not necessarily give visible signs testifying to such embrittlement.

GB-A-1,287,186 describes an anchoring device comprising two stanchions each equipped with a securing means. Each post, parallelepiped and formed by four flat walls, defines a home cradle for a square section pole. Each post is immobilized on a carrier plate by means of weld seams. However, the position of these weld seams and that of the posts are not adapted to the efforts that must support an anchoring device, especially in dynamic mode (fall) when such efforts can reach high intensities.

Similarly, US-A-6,053,281 and U.S. 4,830,341 describe anchoring devices whose bollards are cradles of pole receivers and which are adapted to the forces undergone in static mode, but little or no effort experienced in dynamic mode.

The present invention therefore more particularly aims to overcome these disadvantages. It aims in particular to provide a simple anchoring device and easy to assemble and install on a carrier surface. In addition, the invention relates to an anchoring device whose possible embrittlement is easy to observe, in order to induce the replacement of the damaged elements. The present invention thus relates to an anchoring device whose construction and installation are simple and economical, and which reveals its possible embrittlement.

To this end, the invention relates to an anchoring device which comprises a post equipped with a securing means capable of undergoing a tensile force. According to the invention, the post is generally parallelepipedal and formed by four flat walls, the post is immobilized on a carrier plate by two weld seams along two free edges of one of said flat walls which is in surface abutment on said plate, and the weld seams and the free edges are generally orthogonal to a longitudinal axis of the post and parallel to a main direction in which the tensile force is exerted.

The parallelepipedic term preferably designates a right parallelepiped. By free edges is meant the edges of the wall that are not directly adjacent to another plane wall. By tensile force, is meant mainly a "dynamic" effort, acting briefly and comparable to a shock. The anchoring device is also subjected to tensile forces "static" less intense and exercising continuously. In other words, the post has a hollow box structure welded by two cords on the plate carrier, which is attached to the carrier surface. The present invention therefore allows a construction and a relatively simple installation of an anchoring device capable of presenting a plastic deformation after undergoing a shock to weaken or damage its structure. In addition, the post absorbs energy during the impact and its plastic deformation changes the direction of the reaction forces.

The anchoring device object of the invention is therefore particularly capable of withstanding significant efforts in dynamic mode, for example during the fall of an operator.

In practice, such a post may be composed of a single section of rectangular section tube whose free edges are perpendicular to a central axis of this pipe section. The arrangement of this post relative to the main direction of the force developed by a fall allows it to present a visible deformation in case of significant shock, thus inducing its replacement without delay.

Conveniently, the anchoring device may further comprise plugs adapted to obstruct the lateral openings of the pipe section, these plugs being removable so as to be ejected from these openings when the post is deformed. Such caps can thus fulfill the function of witnessing significant shocks, insofar as they are ejected from the anchoring device.

According to one embodiment of the invention, the securing means may consist of a flat plate fixed on and parallel to the upper wall of the post, this plate having a protruding protruding portion for securing a support of belay, while it is fixed on the upper wall by means of weld seams made around this plate. The lashing plate thus fixed to the post can transmit the forces exerted by a cable or a chain constituting a flexible belay support, so that the post can absorb the energy developed during an impact.

According to an alternative embodiment, the securing means may consist of a ring bolted to the upper wall of the post. Alternatively, the securing means may consist of a bracket bolted to the upper wall of the post and provided with a ring adapted to receive an anti-fall connection or a belay support. Such means make it possible to easily and rapidly secure a flexible belay support.

In practice, the post can be raised above the plate from a height of between 50 mm and 150 mm, it can extend on this plate parallel to the main direction of the tensile force over a width included between 30 mm and 70 mm, and it can extend on this plate transversely to this main direction over a length of between 60 mm and 100 mm, the flat walls having a thickness of between 2 mm and 4 mm. Such dimensions of the post allow, depending on the material that constitutes it, to determine its limit in plastic deformation.

Furthermore, the plate may have the shape of a rectangle whose side length is between 350 mm and 500 mm, and the plate may have a thickness of between 1 mm and 3 mm.

According to a practical embodiment of the invention, the post and the plate may be made of a mild steel. Such a material has a good weldability, which facilitates the installation of the post on the carrier plate.

According to a particular embodiment of the invention, the post may be able to withstand, without plastic deformation, a tensile force exerted along the main direction and intensity less than or equal to 27kN.

• la figure 1 est une représentation schématique en perspective d'un dispositif d'ancrage conforme à une première forme de réalisation de l'invention ;
• la figure 2 est une représentation schématique en vue de côté sans les bouchons du dispositif d'ancrage de la figure 1, lors de l'application d'un effort de traction ayant une intensité donnée ;
• la figure 3 est une représentation analogue à la figure 2 lors de l'application d'un effort de traction ayant une intensité supérieure à celle de l'effort de la figure 2 ;
• la figure 4 est une représentation schématique en vue de dessus d'une partie du dispositif d'ancrage de la figure 1 ;
• la figure 5 est une représentation schématique analogue à la figure 2 pour un dispositif d'ancrage conforme à un second mode de réalisation ; et
• la figure 6 est une représentation schématique analogue à la figure 2 pour un dispositif d'ancrage conforme à un troisième mode de réalisation.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of three embodiments of an anchoring device according to the invention, given solely as a example and with reference to the accompanying drawings in which:

• the figure 1 is a diagrammatic representation in perspective of an anchoring device according to a first embodiment of the invention;
• the figure 2 is a schematic representation in side view without the plugs of the anchoring device of the figure 1 when applying a tensile force having a given intensity;
• the figure 3 is a representation similar to the figure 2 when applying a tensile force having an intensity greater than that of the force of the figure 2 ;
• the figure 4 is a schematic representation in plan view of a part of the anchoring device of the figure 1 ;
• the figure 5 is a schematic representation similar to the figure 2 for an anchoring device according to a second embodiment; and
• the figure 6 is a schematic representation similar to the figure 2 for an anchoring device according to a third embodiment.

The anchoring device illustrated in Figures 1 to 4 comprises a carrier plate 1 horizontal having a plurality of fixing holes 2 for securing, by means of screws or studs represented by their axis lines 21, to an underlying bearing surface belonging to the roof of a building. The bearing surface may for example be constituted by a steel tank on the roof of the building.

According to the invention, the anchoring device comprises a post 3 which is associated with a securing means 4. This securing means 4 consists of a flat plate fixed to the post 3. In addition, the plate 4 has an opening 5 through which can pass, for example, a not shown carabiner for retaining a flexible and movable belay support, also not shown, the latter may consist of a chain or a cable. This cable or chain thus exerts a tensile force on its securing means, in this case on the plate 4.

The tensile force is generated by a mass suspended at the other end of the flexible belay support. This mass may consist of one or more harnessed participants.

The anchoring devices are most often fixed on the bearing surface near an empty space adjacent to the structure requiring intervention. The anchoring devices can be fixed to the edge of the roof of a building to maintain.

Therefore, the tensile force exerted by the cable or the chain on its lashing means 4 is most often directed towards this empty space, so that it has a preferred direction. More exactly, the tensile force decomposed in an XYZ reference linked to the anchoring device has a principal component F _y and one or more secondary components, that is to say of less intensity. This principal component F _y of the effort of traction determines the arrangement of the anchoring device with respect to the carrier plate 1. In the example of Figures 1 to 3 it is assumed that the tensile stress is horizontal and parallel to the Y axis. In other words, it is considered that the tensile stress is equal to its principal component F _y , the other components being most often negligible . We denote by D _F the principal direction of the main component F _y which is parallel to the Y axis.

The post 3 is formed of a section of tubular section generally rectangular and X ₃ is noted the longitudinal and central axis. The post 3 comprises four flat and rectangular plates which form the sides of the pipe section. A first plate 31 rests flat on the plate 1. Two side plates 32 and 33 extend perpendicular to the plate 31 to which they are connected by right-angle fold lines, respectively 34 and 35. An upper plate 36 connects plates 32 and 33 to which it is connected by two fold lines at right angles, respectively 37 and 38.

The post 3 is welded to the carrier plate 1 by means of two welding beads 7A and 7B which extend parallel to the direction D _F. In other words, the weld beads 7A and 7B are orthogonal to the axis X ₃ . The ridges of the post, located at the base of the side walls 31 and 32 and formed by the fold lines 33 and 34 are free of welding.

The weld beads 7A and 7B are arranged along the free edges of the plate 31, that is to say the edges of this plate which are not connected to another plate by a fold line 34 or 35. A of these free edges is visible at the figure 1 with the reference 311, the two free edges 311 and 312 are visible on the figure 4 .

This arrangement of the cords 7A and 7B ensures firm fastening of the post 3 on the plate 1, while limiting the amount of solder required. This provides a simple, effective and economical connection of the post 3 on the carrier plate 1. Note that the weld seams could also be divided into several welding segments.

The post 3 is made of a mild steel, for example, just like the carrier plate 1 and the plate 4. Such a material indeed has good weldability and makes it possible to ensure resistance to plastic deformation determined by ratio to the maximum tensile force F _y likely to exert on the anchoring device in the direction D _F. This steel can be subjected, after welding, to a treatment so as to confer a corrosion resistance.

In the example of the figure 1 , the post 3 has a height of 100 mm, a length of 80 mm and a width of 50 mm. The height, the length and the width being respectively defined with respect to the axes Z, X and Y represented on the figure 1 . These height, length and width can be respectively between 50 mm and 150 mm, between 30 mm and 70 mm in between 60 mm and 100 mm. In addition, the walls of the post 3 are flat and have a thickness of 3 mm, that is to say between 2 mm and 4 mm.

Finally, the carrier plate may be composed of a flat plate mild steel rectangle whose sides have a length between 350 mm and 500 mm and whose thickness is between 1 mm and 3 mm. In the example of fig 1, the plate consists of a square plate of 435 mm side and its thickness is 2 mm. In fact, the dimensions of the plate and the positions of its fasteners depend on the dimensions of the carrier surface and in particular the spacing of the waves of the steel tank.

According to the first embodiment of the invention, the plate 4, which may also be made of mild steel, is welded to the upper wall of the post 3 by means of weld seams 8A, 8B and 8C made on along three edges of the plate 4 on the outer face of the upper plate 36. In addition, a weld bead 8D connects the edge formed by the fold line 37 to the lower surface 41 of the plate 4 which is oriented towards the platinum 1. In fact, the plate 4 has a portion 42 projecting from the post 3 to accommodate the opening opening 5. The weld beads 8A-8D could also consist of disjoint solder segments.

Alternatively, as shown by the Figures 5 and 6 the plate 4 can be replaced by a securing means 204 with a double ring or by a securing means consisting of a 304 "J" bracket provided with a section of tube 341 opening for the passage of a cable . The elements 204 and 304 are fixed on the post 3 by means of a bolt 44 which passes through an orifice provided for this purpose in the upper plate 36 of the post 3. They may be constituted by any means by which one can pass and maintain a flexible belay support.

Furthermore, the anchoring device object of the present invention comprises two plugs 9A and 9B removably mounted on the lateral openings defined by the hollow section of the post 3. The plugs 9A and 9B may consist for example of a polymeric material and are dimensioned so as to be ejected from the lateral openings of the post 3 when the latter undergoes a plastic deformation. The plugs 9A and 9B thus play the role of directly visible witnesses of a plastic deformation, even minor, of the post 3.

Given the dimensions previously discussed, the post 3 has a plastic deformation when it undergoes a tensile force F _y greater than a first value, for example about 27kN.

• Un comportement « neutre » lorsque l'effort F_y est inférieur à la première valeur. Dans ce cas, le potelet 3 présente éventuellement une légère déformation élastique qui disparaît quand l'effort cesse de s'exercer. C'est le mode de fonctionnement normal du dispositif d'ancrage, illustré par la figure 2.
• Un comportement de déformation plastique lorsque l'effort F_y est compris entre la première valeur et une deuxième valeur, par exemple voisine de 42kN. Dans ce cas illustré par la figure 3, le potelet 3 se déforme et les bouchons 9A et 9B sont éjectés. Il faut alors remplacer le potelet 3. Ainsi, l'invention permet de rendre immédiatement visible sur le dispositif d'ancrage l'occurrence d'un choc susceptible d'avoir fragilisé ou endommagé la structure de ce dispositif.
• Un comportement extrême pour un effort F_y supérieur à cette deuxième valeur. Dans ce cas, les soudures 7A et 7B peuvent commencer à s'arracher ou la platine 1 à se déformer. Il faut néanmoins que cette deuxième valeur soit largement supérieure à l'intensité d'un choc consécutif à la chute d'un intervenant, ce qui garantit la sécurité de cet intervenant.

In fact, the geometry and the materials of the anchoring device according to the invention define three behaviors of the post 3, namely:

• A behavior "neutral" when the force F _is less than the first value. In this case, the post 3 may have a slight elastic deformation which disappears when the effort ceases to be exercised. This is the normal operating mode of the anchoring device, illustrated by the figure 2 .
• A plastic deformation behavior when the effort F _y is between the first value and a second value, for example close to 42kN. In this case illustrated by the figure 3 , the post 3 is deformed and the plugs 9A and 9B are ejected. It is then necessary to replace the post 3. Thus, the invention makes it possible to immediately make visible on the anchoring device the occurrence of a shock that may have weakened or damaged the structure of this device.
• Extreme behavior for an effort F _y greater than this second value. In this case, the welds 7A and 7B may begin to tear or the plate 1 to deform. However, this second value must be much greater than the intensity of a shock following the fall of a stakeholder, which guarantees the safety of this stakeholder.

This is for example the case when a stakeholder falls down and is held by the cable and its harness, which then suddenly transmit a tensile force F _y to the anchoring device.

The present invention has been described here for a flexible anchoring support, such as a lifeline, but it is also applicable to a fixed anchor point with an anti-fall connection connected to the harness of the speaker.

Claims (10)

1. Anchorage device comprising a bracket (3) which is equipped with securing means (4; 204; 304) which can be subjected to a traction force (F_γ), the said bracket (3) being globally parallelepiped, and formed by four flat walls (31, 32, 33, 36), the said bracket (3) being immobilised on a support plate (1) by two welding beads (7A, 7B) which border two free edges (311, 312) of one of the said flat walls (31) which is supported on the surface of the said plate (1), characterised in that the said welding beads (7A, 7B) and the said free edges (311, 312) are globally at right-angles to a longitudinal axis (X₃) of the bracket (3), the axis (X₃) extending in a direction parallel to the four flat walls, and parallel to a main direction (D_F)according to which the said traction force (F₇)is exerted.
2. Anchorage device according to claim 1, characterised in that the said bracket (3) is in the form of a truncated tube with a rectangular cross-section, the said free edges (311, 312) being perpendicular to a central axis (X₃) of the said truncated tube.
3. Anchorage device according to claim 2, characterised in that it additionally comprises stoppers (9A, 9B) which can block lateral openings in the said truncated tube, the said stoppers (9A, 9B) being removable, such that they can be ejected from the said openings when the bracket (3) is deformed.
4. Anchorage device according to one of the preceding claims, characterised in that the said securing means consists of a flat plate (4) which is secured on, and parallel to, an upper wall (36) of the said bracket (3), the said plate (4) having a perforated (5) projecting part (42) for securing of a fastening support, the said plate (4) being secured on the said upper wall (36) by means of welding beads (8A-8C) which are provided around the said plate (4).
5. Anchorage device according to one of claims 1 to 3, characterised in that the said securing means consists of a ring (204) which is bolted (44) onto the upper wall (36) of the said bracket (3).
6. Anchorage device according to one of claims 1 to 3, characterised in that the said securing means consists of an angle iron (304) which is bolted (44) onto the upper wall (36) of the said bracket (3), and is provided with a ring which can receive an anti-fall connection or a fastening support.
7. Anchorage device according to one of the preceding claims, characterised in that the bracket (3) rises above the said plate (1) by a height of between 50 mm and 150 mm, in that the bracket (3) extends on the said plate (1) parallel to the said main direction (D_F) along a width of between 30 mm and 70 mm, and in that the bracket (3) extends on the said plate (1) transversely to the said main direction (D_F) along a length of between 60 mm and 100 mm, the said flat walls (31, 32, 33, 36) having a thickness of between 2 mm and 4 mm.
8. Anchorage device according to one of the preceding claims, characterised in that the plate (1) is in the form of a rectangle, the length of the sides of which is between 350 mm and 500 mm, and in that the plate (1) has a thickness of between 1 mm and 3 mm.
9. Anchorage device according to one of the preceding claims, characterised in that the bracket (3) and the plate (1) consist of low-carbon steel.
10. Anchorage device according to one of the preceding claims, characterised in that the bracket (3) can withstand without plastic deformation a traction force (F_γ) which is exerted according to the main direction (D_F), and has an intensity of 27kN or less.

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