FR2986850A1 - Signal warning device for locating underground network of pipes or buried cables, has side signal devices removably fixed on support grid and placed with specific distance of lateral edges of support grid - Google Patents

Abstract

The device (2) has a plastic support grid (3) including two lateral edges (4), and an elongated central signal device (7) fixed on the support grid such that the central signal device is placed in a central part of the support grid. Two side signal devices (5) are removably fixed on the support grid and placed with less than 70 mm of the lateral edges of the support grid. Distance (D) between the side signal devices is smaller than or equal to approximately 150 mm. Each signal device is made from plastic such as polypropylene.

Description

The present invention relates to a warning device for the identification of buried networks, such as underground pipes or cables. In order to facilitate the identification of underground pipes or cables, and to prevent their degradation during work carried out subsequently, it is known to use warning devices. A warning device is placed above the buried pipe or cable, at a distance of about 30 cm from the upper generator of the latter or the latter, so that the tool performing a search 10 in the ground reaches the warning device before reaching the pipe or buried cable. In this way, the operator is warned that one should not dig at this place because there is a risk of deterioration of the buried work. The oldest solution consists in producing a warning device constituted by a mesh of synthetic material of homogeneous structure. This grid having no sufficient mechanical strength, it does not give satisfaction because, when it is hooked by the bucket of a digger, it breaks immediately, without we have, of course, pieces of grilling protruding into the walls of the excavation, or out of the bucket, allowing immediate visualization. To overcome this drawback, it is known, in particular from document FR 2 190241, to associate with a support grid having a low mechanical strength longitudinal strips of material having a greater mechanical strength, such as stretched polypropylene. When one of the bands of such a warning device is hooked by the bucket of a mechanical shovel, the resistance offered by the band allows it to exceed the walls of the excavation carried out, and thus to allow a operator to view it. However, such a warning device provides signaling of a buried pipe or cable only if the bucket of the excavator hangs more than half the width of the warning device. Indeed, when only a portion of the support grid is hooked and torn off by the bucket of a shovel, for example a lateral portion of the support grid disposed between one of the lateral edges of the support grid and the strip adjacent to this edge, the torn portion is most often buried under the cuttings present in the bucket, and therefore not visible to the operator.

It is then possible for an operator not to identify the presence of a pipe or a buried cable, and thus to damage it. The present invention aims to remedy this disadvantage. The technical problem underlying the invention is thus to provide a warning device for the identification of buried networks which is simple and economical structure, and which allows, certainly, the identification of these buried networks by visualization of the least one signaling element at the level of the search and / or the bucket of the machine used to perform this search.

For this purpose, the present invention relates to a warning device for locating underground networks, comprising: a plastic support screen comprising first and second side edges, an elongated central signal element fixed to the grid 15 of medium, the central signaling element being arranged in a central part of the support grid, and first and second lateral signaling elements which are elongated and fixed on the support grid, the first and second lateral signaling elements being arranged respectively at less than 70 mm from the first and second side edges of the support grid. The presence of a central signaling element and the arrangement of the two lateral signaling elements at less than 70 mm from the lateral edges of the support grid make it possible to ensure, during excavation work, a snap-in and pull-out of the minus one of the signaling elements with the bucket of a shovel, and to provide an operator with a visualization of the warning device at the bucket and / or both walls of the excavation carried out, and therefore a signaling of the buried network covered by the warning device. Preferably, the distance separating two adjacent signaling elements is less than or equal to about 150 mm. These provisions make it possible to ensure, during excavation work, a hooking and tearing of at least one of the signaling elements including the bucket of a micro-shovel. According to one embodiment of the invention, each signaling element is made of plastic, such as polypropylene.

Advantageously, each signaling element is made of a substantially inextensible material. According to one embodiment of the invention, each signaling element is removably attached to the support grid. The attachment of each signal element can be achieved, for example, by applying a pressure of the signal element on the support grid, while the latter is still in a malleable state given its temperature. Preferably, each signaling element is continuous. Advantageously, each signaling element has a greater breaking strength than that of the support grid. According to one embodiment of the invention, each signal element has a breaking strength greater than or equal to 50 daN. According to one embodiment of the invention, each lateral signaling element extends longitudinally and has a length substantially corresponding to that of the support grid. According to a first variant embodiment of the invention, the central signaling element 20 has a length greater than that of the support grid and is folded in contact with the support grid. Thus, the difference in length between the central signaling element and the support grid constitutes a reserve which, during attachment by the bucket of the excavator, unwinds and is used for visualization at the level of the machine. bucket and at the level of the excavation. This reserve is sufficient to allow traction on the central signal element, without breaking it to a height for viewing the warning device both at the bucket, and at the walls of the excavation. The central signal element may be folded accordionally, sinusoidally or spirally folded. The central signaling element may be a cord or a ribbon. The central signaling element may be a multi-filament compound. According to a second variant embodiment of the invention, the central signaling element comprises a plurality of zones of fragility offset longitudinally from each other. Thus, when the central signal element is hooked by the bucket of a shovel, this signal element is initially pulled by the bucket, without breaking, and in a second time is torn at the level of at least one zone of weakness, allowing a display of a portion of this signaling element by the driver of the machine at the bucket and / or both walls of the excavation performed. Each zone of weakness of the central signaling element comprises, for example, transverse pre-cuts. Each zone of weakness of the central signal element has, for example, a breaking strength greater than or equal to 50 daN. According to one embodiment of the invention, the central signaling element is formed by an extruded plastic strip, and each zone of weakness of the central signaling element is arranged to guide a tear of the strip transversely to the direction of the latter. Preferably, each lateral signaling element comprises a plurality of zones of fragility offset longitudinally from each other. Each zone of weakness of each lateral signaling element comprises, for example, transverse pre-cuts. Each zone of weakness of each lateral signaling element may have a breaking strength greater than or equal to 50 daN.

According to one embodiment of the invention, each lateral signaling element is formed by an extruded plastic strip, and each zone of weakness of each lateral signaling element is arranged to guide a tear of the respective strip transversely to the direction. of the latter.

According to one embodiment of the invention, the warning device comprises at least one elongated intermediate signaling element and fixed on the support grid between the central signaling element and one of the first and second lateral signaling elements. It should be noted that the dimensional characteristics and the physico-chemical properties of the stripping device according to the invention are in particular in accordance with the European standard EN 12.613. Anyway, the invention will be better understood from the following description with reference to the attached schematic drawing showing, by way of non-limiting examples, several embodiments of this warning device.

Figure 1 is a flat view of a section of a warning device according to a first embodiment of the invention. Figure 2 is a cross-sectional view of an excavation in progress by a mechanical shovel which only the bucket is shown in high position. Figure 3 is a plan view of a portion of a warning device according to a second embodiment of the invention. Figure 1 shows a warning device 2 for the identification of buried networks, such as pipes or cables. The warning device 2 comprises a support grid 3 made of plastic, for example polypropylene, having two lateral edges 4. The warning device 2 furthermore comprises two elongate lateral signaling elements 5 fixed to the support grid 3. Each Lateral signaling element 5 is substantially inextensible and extends substantially parallel to the direction of laying of support grid 3. Each lateral signaling element 5 has a length substantially corresponding to that of support grid 3. Each lateral signaling element 5 has a width of between 30 and 50 mm, for example about 35 mm. The two lateral signaling elements 5 are respectively located less than 70 mm from the lateral edges 4 of the supporting grid 2, and preferably within 40 mm from the lateral edges 4. Each lateral signaling element 5 is in the form of 1, in the form of an extruded strip of plastic material, for example polypropylene. Each lateral signaling element 5 comprises a plurality of zones of weakness 6 offset longitudinally from each other. Each zone of weakness 6 is arranged to guide a tear of the respective strip 30 transversely to the direction of the latter. Each zone of weakness 6 has a breaking strength greater than or equal to 50 daN. Each zone of weakness 6 preferably comprises transverse pre-cuts. The warning device 2 also comprises a central signaling element 7 which is elongated and fixed on the supporting grid 3. The central signaling element 7 is arranged in a central part of the support grid 3. The central signaling element 7 is formed, in the embodiment shown in Figure 1, by a substantially inextensible bead of plastic material, for example polypropylene, of greater length than that of the section of the supporting wire mesh with which it is associated, and stored against it in the form of a substantially sinusoidal arrangement. The width L of the signaling area delimited by the central signaling element 7 is preferably between 70 and 130 mm, and is for example equal to about 100 mm. Preferably, the distance D between two adjacent signaling elements is less than or equal to about 150 mm. The distance D may be equal to about 10 mm for a warning device 2 having a width of about 200 mm, equal to about 60 mm for a warning device 2 having a width of about 300 mm, or equal to about 110 mm for a warning device 2 having a width of about 400 mm.

The two lateral signaling elements 5 and the central signaling element 7 are fixed on the support grid 3, for example by mechanical pressure, while the support grid 3 is still in a malleable state, given the temperature at which it is realized. Thus, the fixing of the lateral and central signaling elements is removable. Therefore, when a pull is exerted on one of the signaling elements, it separates from the support grid 3. FIG. 2 shows the implementation of this warning device 2 when it is hooked by the bucket 8 of a mechanical shovel. The warning device 2 is shown above a buried pipe 9. When the bucket 8 catches the warning device 2, and it is raised, the support grid 3 will break immediately. The lateral tensile-resistant signal elements will tend to exit the excavation before breaking, leaving for example a piece 5a visible along one of the walls of the excavation, and also a visible piece 5b of the excavation. one side of the backhoe bucket. As for the central signaling element 7, it will be pulled by the bucket 8, its length and its resistance ensuring its elevation without breaking by the bucket 8, allowing immediate visualization by the driver of the machine both at the bucket 8 on both sides of it, only at the two opposite walls of the excavation.

FIG. 3 shows a warning device 2 according to a second embodiment of the invention which differs from that shown in FIG. 1 essentially in that the central signaling element 7 is formed by an extruded plastic strip, for example polypropylene, and has a plurality of zones of fragility 9 offset longitudinally from each other. Each zone of weakness 9 is arranged to guide a tear of the strip transversely to the direction of the latter. Each zone of weakness 9 has a breaking strength greater than or equal to 50 daN, and preferably comprises transverse pre-cuts. The central signaling element 7 has a width of between 30 and 80 mm, for example about 50 mm. The distance D may be equal to about 5 mm for a warning device 2 having a width of about 100 mm, equal to about 35 mm for a warning device 2 having a width of about 200 mm, equal to about 85 mm for a warning device 2 having a width of about 300 mm, or equal to about 135 mm for a warning device 2 having a width of about 400 mm According to an alternative embodiment not shown in the figures, the warning device 2 could comprise at minus one intermediate signaling element elongated and fixed on the supporting grid 3 between the central signaling element 7 and each of the lateral signaling elements 5. Each intermediate signaling element could be formed by an extruded plastic strip, for example polypropylene, having a structure substantially identical to that of the lateral signaling elements.

As goes without saying, the invention is not limited to the embodiments of this warning device, described above as examples, it encompasses all variants.

Claims (13)

REVENDICATIONS1. Warning device (2) for the identification of buried networks (9), comprising: - a support grid (3) of plastics material comprising first and second lateral edges (4), - an elongate central signaling element (7) and attached to the supporting grid (3), the central signaling element (7) being arranged in a central part of the supporting grid, and - first and second lateral signaling elements (5) elongated and fixed on the grid of the support grid support (3), the first and second lateral signaling elements (5) being respectively less than 70 mm from the first and second lateral edges (4) of the support grid. 2. Warning device according to claim 1, wherein the distance (D) separating two adjacent signaling elements (5, 7) is less than or equal to about 150 mm. A warning device according to claim 1 or 2, wherein each signal element (5, 7) is made of a plastics material, such as polypropylene. A warning device according to one of claims 1 to 3, wherein each signaling element (5, 7) is releasably attached to the support grid (3). 5. Warning device according to one of claims 1 to 4, wherein each signal element (5, 7) is continuous. 30 Warning device according to one of claims 1 to 5, wherein each signal element (5, 7) has a breaking strength greater than or equal to 50 daN. 7. Warning device according to one of claims 1 to 6, wherein each lateral signaling element (5) extends longitudinally andpresents a length substantially corresponding to that of the support grid (3). 8. Warning device according to one of claims 1 to 7, wherein the central signaling element (7) has a length greater than that of the support grid (3) and is folded in contact with the support grid (3). ). The warning device according to one of claims 1 to 7, wherein the central signaling element comprises a plurality of frailty zones (9) offset longitudinally from each other. 10. Warning device according to claim 9, wherein each zone of weakness (9) of the central signal element (7) comprises transverse precuts. 15 11. A warning device according to one of claims 1 to 10, wherein each lateral signaling element (5) comprises a plurality of fragile areas (6) offset longitudinally from each other. 20 12. Warning device according to claim 11, wherein each zone of weakness (6) of each lateral signaling element (5) comprises transverse precuts. 13. Warning device according to one of claims 1 to 12, which comprises at least one elongated intermediate signaling element and fixed on the support grid (3) between the central signaling element (7) and one of the first and second lateral signal elements (5).