FR2981708A1 - Fastening screw for fixing insulating panels used in insulation system for wall of building, has net extending over part of tip and body and including portion presenting truncated envelope, where pitch of net is greater than certain mm - Google Patents

Abstract

The screw (1) has a monoblock made of a synthetic material and including a rod (3) and a head (2). The rod includes an elongated body (7) extending from the head, and is approximately perpendicular to a support surface (4). A tip (8) is placed at an end of the body opposed to the head. A helicoid net (9) extends over a part of the tip and the body, and is remote from the head. The net has diameter (H) increasing toward the head. The net includes a portion presenting a truncated envelope (18), where a pitch (P) of the net is greater than 8 mm. Independent claims are also included for the following: (1) an insulation system for an wall of a building (2) a kit for assembling insulating panels (3) a method for fixing insulating panels.

Description

The invention relates to fastening devices for insulating panels, and more specifically fastening screws and assemblies of insulating panels.

To improve the thermal and / or sound insulation of buildings, it is customary to use layers of flexible or semi-rigid materials, for example insulating panels. It is desirable that these panels have good fire resistance and this is one of the reasons why more and more panels are used based on mineral fibers, and in particular rock wool. These panels can be made with different densities and thicknesses as needed. The use of such insulating panels is widespread in new construction but also in the renovation and rehabilitation of existing buildings. Energy saving research is regularly pushing industry players to increase thermal capacities. The Applicant has conducted research to increase the thickness, especially with assembling systems of new insulating layers between them. The Applicant has, moreover, developed a system for assembling new insulating layers on pre-existing insulating layers. The Applicant seeks to preserve old insulation layers that are insufficient in comparison with current standards, to which new insulating layers are added. There was no satisfactory solution compatible with the majority of the existing varieties of insulating layers, or a multi-functional solution to the point of being usable in the vast majority of configurations of insulation systems to be created or modified, in particular to fix a panel on the other. The invention improves the situation.

The assembly of insulating panels fastening device is made in one piece of synthetic material and comprising a head and a rod. The head comprises a flat bearing surface on one of the insulating panels, a face opposite to the bearing face provided with at least one drive fin. The driving fin may for example be handled by at least two fingers. The fin extends to a selected distance from the opposite face, the distance being greater than 10 mm. The shaft comprises an elongate body extending from the head and substantially perpendicular to the bearing face, a tip disposed at one end of the body opposite the head, and at least one helical thread. The helical thread extends over at least a portion of at least one of the tip and the body and is remote from the head. The helical thread having an increasing diameter towards the head, the helical thread comprising a portion having a frustoconical envelope and the pitch of the helical thread being greater than 8 mm. An air gap, such as for example a ventilation gap, is maintained between a outer surface of the insulating panels and an additional wall or coating fixed opposite the outer surface. The fin of the screw head makes it possible to limit the phenomena of condensation and thus to improve the long-term efficiency of the insulating panels. The screw may comprise a hollow impression of rotating drive. The hollow footprint not only limits the amount of material constituting the screw, making it lighter and cheaper but it also allows screwing by a conventional tool in addition to manual screwing. Demolding is easy during manufacture. The hollow impression can extend axially to the vicinity of the net. This makes it possible to apply the tightening torque as close as possible to the thread in order to limit the forces, in particular in torsion, applied to the screw shank when tightening. The body of the stem may be cylindrical or frustoconical. The body of the stem may include flutes. The grooves improve the mechanical strength while limiting the mass of the rod. The body of the rod may have a length to diameter ratio greater than 20. It is then possible to cross large thicknesses of insulating panels while requiring a torque screw compatible with a manual screwing.

The pitch of the helical thread may be greater than 15 mm, preferably 25 mm. This allows a low number of turns for fast screwing. Screwing is thus ergonomic and the rigidity of the assembly, in particular by the repeatability of the movement performed by the operator, is reasonable. The risk of fatigue and occupational disease is reduced.

The helical thread may comprise a portion having a cylindrical envelope. This allows to lengthen the developed length of the helical thread and therefore its range, that is to say the total surface of the net in the insulating panels without widening the tapped space in the insulating panels.

The bearing face of the head may be provided with bosses. This provides an anti-loosening effect by hooking the screw head to the outer surface of an insulating panel. The bosses may be asymmetrical with respect to a section plane passing through an axis of the rod so as to confer a higher friction torque in a direction of unscrewing with respect to a screwing direction. The slight friction at the end of screwing causes an increase in the necessary torque at the end of screwing. This is an indicator for the operator and reduces the risk of over-screwing. The screw may comprise two fins extending in the radial direction on either side of an axis of the rod and extending axially to a selected distance from the opposite face. The fins can be coplanar. The fins may be curved about axes parallel to the axis of the shaft making the screw more ergonomic. For reasons of practicality, it is preferable to minimize the use of specific tools for mounting while limiting the time and number of operations during assembly. The Applicant has found that there is no device or system which the driving force of the fingers of an operator, without tools, is sufficient to mount on the one hand and the number of turn screw is compatible with a industrially reasonable assembly time. The body may include a hollow portion. This reduces the amount of material constituting the screw, limits the mass and therefore the cost of manufacture and use. In addition, the assembly of the various layers must limit the thermal bridges. There is currently no satisfactory means of fixing this aspect. Known means tend to facilitate thermal conduction at least locally. In another aspect, the invention relates to a building wall insulation system comprising at least a first insulating panel and at least a second insulation panel having a density of between 10 and 300 kg / m3, mutually superimposed in the common direction. their thicknesses and interconnected by at least one screw, said screw being made in one piece of synthetic material and comprising a head and a rod, the head comprising a flat bearing surface on one of said insulating panels, a face opposite to the face support member provided with at least one drive fin with at least two fingers, said fin extending to a selected distance from the opposite face, said distance being greater than 10 mm, the stem comprising an elongate body extending from the head and substantially perpendicular to the bearing face, a tip disposed at one end of the body opposite the head, and at least one helical thread, the helical thread extending at least over a portion of at least one of the tip and the body and being remote from the head, the helical thread having an increasing diameter towards the head, the helical thread comprising a portion having a frustoconical envelope, the pitch of the helical thread being greater than 8 mm, the screw being arranged substantially in the direction of the thicknesses of the insulating panels, a portion of the rod passing through the thickness of the second panel, the net being disposed at least partially in the first panel and the bearing face being in contact with an outer surface of the second panel.

The assembly system, for reasons of cost and time of realization, adapts to existing devices, structures and methods on the market. In particular, the high cost of the manufacturing facilities of the elements participating in the insulating system, for example the support structures, makes the modifications difficult. The applicant proposes a device and a system whose use avoids investments in other industries. To limit the costs and facilitate the use of such devices in renovation, the bearing structures in their current dimensions are preserved. The Applicant proposes means and methods of assembly that can be used in new construction and renovation. The renovation may include the addition of at least one new insulation layer in addition to at least one existing insulation layer. The different layers may have different characteristics in particular of size, density, density, heat resistance and fire resistance. The system may further comprise an additional wall supported on at least one fin of the screw such that an air gap, such as a ventilation gap, of non-zero thickness is formed between the additional wall and the outer surface of the second panel. The air gap may have a thickness of at least 10 mm. This reduces the phenomena of condensation and moisture passage between the insulating panels and an additional wall, for example dressing.

The first insulation board of the system can be embedded in a profile and held in the profile by a flap of the profile. The second insulating panel can be attached to the first insulating panel by the screw disposed away from the profile. The phenomena of thermal bridges are diminished. In another aspect, the invention relates to a mounting kit of a second insulating panel on a first insulating panel. The kit comprises at least one second insulation panel of average density of between 10 and 300 kg / m3 each and a fixing screw. Said screw is made in one piece of synthetic material and comprising a head and a rod, the head comprising a flat bearing surface on one of said insulating panels, a face opposite to the bearing face provided with at least one drive fin said fin extending to a selected distance from the opposite face, said distance being greater than 10 mm, the stem comprising an elongate body extending from the head and substantially perpendicular to the bearing face, a tip disposed at one end of the body opposite the head, and at least one helical thread, the helical thread extending at least over a portion of at least one of the tip and the body and being remote from the head, the helical thread having an increasing diameter towards the head, the helical thread comprising a portion having a frustoconical envelope, the pitch of the helical thread being greater than 8 mm. The second insulating panel is intended to be fixed on a first insulating panel so that the first insulating panel and the second insulating panel are mutually superposed in the common direction of their thicknesses and linked together by the screw. The screw is intended to be screwed substantially in the direction of the thicknesses of the insulating panels, a portion of the rod passing through the thickness of the second insulating panel, so that the net is engaged in the first insulating panel and so that the face in contact with an outer surface of the second insulating panel. In one embodiment the at least one fin may be driven by at least two fingers.

In another aspect, the invention relates to a method of attaching a second insulating panel to a first insulating panel comprising the manual screwing or using a tool of a fixing screw through the thickness of a second insulating panel and engaging the helical thread of the screw in the first insulating panel.

The method may be provided so that the tightening torque of the screw is between 0.2 and 2.0 Nm, preferably between 0.3 Nm and 1.8 Nm and more preferably between 0.5 and 1, 5 Nm or between 0.6 and 1.3 Nm in rock wool with an average density of 50 kg / m3. This allows manual screwing while reducing the risk of accidental unscrewing.

The method may be provided so that the tightening torque of the screw is between 0.2 and 2.0 Nm, preferably between 0.3 Nm and 1.8 Nm and more preferably between 0.5 and 1, 5 Nm or between 0.6 and 1.3 Nm in polyurethane (PUR) or polyisocyanurate (PIR). This allows manual screwing while reducing the risk of accidental unscrewing.

The system may be arranged so that the first insulating panel is disposed at least partly in a profile and held therein by a flap of the profile, and the second insulating panel is disposed outside the section, the screw being arranged at a distance from the profile. This type of system reduces the phenomenon of thermal bridge by conduction between the fixing screws and the profiles often made of thermally conductive materials. On the other hand, such a system can also be used in a variety of building applications where insulation layers need to be securely attached to pre-existing insulation layers or a first layer of insulation. in a double / multilayer assembly, for example in ventilated facade systems, hollow walls, etc.

The insulating panels preferably comprise one or more materials chosen from rockwool, glass wool, or plastic-based foams, expanded polystyrene (EPS) or extruded (PSX), polyurethane (PUR), polyisocyanurate (PIR) ), or expanded polypropylene (EPP). Other features and advantages of the invention will appear on examining the detailed description below, and the attached drawings in which: - Figure 1 is an exploded schematic view of an assembly of insulating panels, - the figure 2 is a sectional view of an assembly of insulating panels of the ventilated type, FIG. 3 is a schematic perspective view of a fixing screw, FIG. 4 is a diagrammatic view in longitudinal section of a screw of FIG. FIG. 5 is a radial sectional view along VV of a fixing screw, FIG. 6 is a side view in detail of the screw of FIG. 5, FIG. 7 is a perspective view. 8 is a view from above of FIG. 7, FIG. 9 is a sectional view along the axis IX-IX of FIG. 8, FIG. section along the XX axis of Figure 8, - Figure 11 is a perspective view of a screw head, and - Figure 12 is a view in a neck Axial pe of a screw head different from that of Figure 11. The accompanying drawings are essentially of a certain character and may not only serve to complete the invention, but also contribute to its definition, if necessary.

An assembly system of insulating panels 23, 123, 24, 124 by means of screws 1 for fixing in a building is shown during assembly in FIG. 1. A building comprises a fixed support 20, for example a concrete pillar or a metal pole. Metal sections 21, 121 are positioned against the fixed support 20 and fixed in a known manner. The assembly system comprising the sections 21, 121 assembled and the insulating panels 23, 123, 24, 124 also form a "cladding". Although, in the field of insulation, the term siding can usually designate a vertical non-load bearing outer skin, the word siding is here to be understood in its most general sense, that is to say a non-load bearing coating. interior, exterior or intermediate, vertical or not, for example a siding.

The profiles 21, 121 are similar. The profiles 21, 121, as their name suggests, are parts having a profile (visible in section in Figure 1) substantially identical over their entire length, in the direction perpendicular to the plane of Figure 1, in particular obtained by folding . The profiles 21, 121 may be obtained by spinning, rolling, profiling and / or drawing. This type of part is inexpensive to manufacture. On the other hand, a localized modification in its length, that is to say, forming an exception to its profiled character, is theoretically possible but entails significant costs. The profile 21, in the example described here, comprises a core 22 provided with longitudinal reinforcing ribs 30 stiffening the core 22. With the exception of the ribs 30, the core 22 is substantially flat. The ribs 30 prevent the soul 22 is not veiled. The profile 21 is here mounted substantially perpendicular to the fixed support 20, that is to say in a substantially horizontal direction. The profile 21 also comprises an upper wing 31 and a lower wing 32. The upper wing 31 and the lower wing 32 are arranged at the top, respectively at the bottom, of the web 22. The upper and lower wings 31 and 31 are arranged in planes substantially perpendicular to that of the core 22 and extend on the same side of the core 22, here the opposite side to that of the fixed support 20. In other words, the upper and lower wings 31 and 32 form the branches a C whose core 22 is the body, in section along the plane of FIG. 1. The distance between the upper wing 31 and the lower wing 32 defines a housing height of the profile 21. The upper wings 31 and bottom 32 extend in parallel directions from left to right in FIG. 1 over widths of near values. The widths of the upper and lower wings 31 and 31 define the thickness of the profile 21, for example 10 cm. This thickness is to be distinguished from the thickness of the sheet forming profile 21, typically a few millimeters.

The upper and lower wings 31 and 32 are each provided at their opposite ends to the core 22, an upper flap 34, respectively lower 35, oriented here downwardly. The upper flap 34, extends substantially vertically and towards the lower flange 32 from the end of the upper flange 31, The lower flap 35 extends substantially vertically and towards the opposite of the upper flange 31 since the end of the lower flange 32. The profiles 21, 121 are mounted successively on each other. Each lower flange 32 of a profile 21 at least partially covers an upper flange 31 of another profile 121 disposed immediately below. The lower flange 32 and the lower flap 35 of the upper section 21 substantially cover the upper flange 31 and the upper flap 34 of the lower section 121. The dimensions of the wings and flaps are chosen in correspondence. The core 22, the upper and lower flanges 31 and 32, the upper and lower flaps 35 and a plane connecting the two flaps define an open envelope of the profile 21. The assembly, in the example described here, comprises two first insulating panels 23 and 123 similar, on the one hand, and two second insulating panels 24 and 124 similar on the other. The first insulating panels 23, 123 and the second insulating panels 24, 124 may comprise, for example, rock wool, glass wool, plastic-based foams, expanded polystyrene (EPS or XPS), polyurethane (PUR), polyisocyanurate (PIR), or expanded polypropylene (EPP). The first insulating panels 23, 123 and the second insulating panels 24, 124 are, here, of rectangular parallelepiped general shape. Before assembly, the first insulating panels 23, 123 and / or the second insulating panels 24, 124 can be rolled on themselves. The first insulating panels 23, 123 and the second insulating panels 24, 124 each comprise, in descending order of their three dimensions, a length, a height and a thickness. The lengths are oriented, here, horizontally and parallel to the length of the profiles 21, 121, in a direction perpendicular to the plane of FIG. 1. The heights are oriented, here, vertically and perpendicular to the length of the profiles 21, 121, in a direction substantially parallel to the height of the profiles 21, 121. The thicknesses are oriented, here, horizontally and perpendicular to the length of the profiles 21, 121, in a direction parallel to the thickness of the profiles 21, 121.

For each of the first insulating panels 23, 123 on the one hand and second insulating panels 24, 124, on the other hand: - an internal surface 28, 38, perpendicular to the direction of the thickness of the parallelepiped and oriented here, towards the core 22 of the profile 21, 121, an external surface 29, 39, perpendicular to the direction of the thickness of the parallelepiped and oriented here, opposite the core 22 of the profile 21, 121, - an upper surface 26, 36, perpendicular to the direction of the height of the parallelepiped and directed, here, upwards, - a lower surface 27, 37, perpendicular to the direction of the height of the parallelepiped and oriented, here, down. two surfaces of opposite section perpendicular to the direction of the length of the parallelepiped and not visible in FIG. 1. The first insulating panels 23, 123, in the example described here, have heights chosen to fit between the wing. upper 31 and the lower flange 32 of the section 21, 121.

The first insulating panels 23, 123 have a thickness greater than that of the sections 21, 121. The thickness of the first insulating panels 23, 123 is, for example, twice the thickness of the sections 21, 121. The first insulating panels 23, 123 are here each provided with an upper notch 33. The upper notch 33 is formed from the upper surface 26 of each of the first insulating panels 23, 123. The upper notch 33 is disposed substantially parallel to the length of the first insulating panel 23, 123. The upper notch 33 has a depth adapted to accommodate the upper flap 34 of a first section 121 and the lower flap 35 of another section 21 disposed immediately above the first. The upper notch 33 has a width, oriented in the direction of the thickness of the first insulating panel 23, 123, adapted to accommodate the upper flap 34 of a first section 121 and the lower flap 35 of another section 21 disposed immediately above the first. The upper notch 33 is disposed substantially mid-thickness of the first insulating panel 23, 123. In the mounted state of the assembly, the first insulating panel 23 is disposed in the upper profile 21 between the upper flange 31 and the first one. 32. The first insulating panel 123, similar to the first insulating panel 23, is similarly arranged in the lower section 121. The interaction between at least one of the flaps of the two profiles 21, 121 superimposed and the notch 33 of the first insulating panel 123 keeps the first insulating panel 123 in the lower section 121.

The upper surface 26 of the first insulating panel 123 and the lower surface 27 of the first insulating panel 23 are mutually facing each other or in contact. This pair of surfaces 26 and 27 of the first two insulating panels 23 and 123 may be in contact or outcrop and form an abutment. This pair of surfaces 26 and 27 of two first insulating panels 23 and 123 may be spaced apart by a gap or a clearance. The interface comprising the upper surface 26 of the first insulating panel 123, the lower surface 27 of the first insulating panel 23 and the The difference between these two surfaces (null or not) is here called "connection region". The second insulating panels 24, 124 superimposed have similar connection regions.

The connection region of two first insulating panels 23 and 123 vertically superimposed is substantially aligned horizontally with the wings 31 and 32 of the profiles 21, 121. A gap may remain between two first insulating panels 23, 123 consecutive. One solution is to have a thickness or an additional layer of insulation. The additional thickness of insulation is, in the example described here, formed by the second insulating panels 24, 124. The connection regions of the first insulating panels 23, 123, on the one hand, and the second insulating panels 24, 124, on the other hand, are shifted. In other words, the upper surfaces 26 and lower 27 of the first insulating panels 23, 123, on the one hand, and the upper surfaces 36 and lower 37 of the second insulating panels 24, 124, on the other hand, are offset. The connection region between two successive second insulating panels 24, 124 is located vertically away from the connection regions of the first insulating panels 23, 123. The offset may be, for example, half a height. In the direction of the length of the first insulating panels 23, 123 and the second insulating panels 24, 124, the regions of connection of the section surfaces between two first insulating panels 23, 123 side by side on the one hand and the connection regions cross-sectional areas between two second insulating panels 24, 124 side by side may be offset, for example by half a length. To facilitate the offsets, the first insulating panels 23, 123 and the second insulating panels 24, 124 have substantially identical lengths and substantially identical heights.

The connection region between two successive second insulating panels 24, 124 is located, in the direction of the thickness, away from the upper flaps 34 and lower 35. This avoids thermal bridges. The first insulating panels 23, 123 and the second insulating panels 24, 124 are mutually superposed in the common direction of their thicknesses. As shown in FIG. 1, an additional layer 25 can be inserted between the first insulating panels 23, 123 and the second insulating panels 24, 124 and more precisely between the outer surfaces 29 of the first insulating panels 23, 123 and the internal surfaces 38. second insulating panels 24, 124. The additional layer 25 may have a role of sealing and / or reflection of infrared radiation. The additional layer 25 may, for example, comprise aluminum. The thickness of the additional layer 25 is several orders of magnitude smaller than the thicknesses of the insulating panels 23, 123, 24, 124, for example of the order of 20 to 50 μm, in particular for aluminum. . The additional layer 25 is easily perforable, in particular by the application, on screwing, of a manual force. Alternatively, the additional layer 25 may be disposed against the inner surface 28 of the first insulating panels 23, 123 or against the outer surface 39 of the second insulating panels 24, 124, or several additional layers 25 may be disposed at several of the aforementioned locations .

Fixing the second insulating panels 24, 124 to the first insulating panels 23, 123 is provided by fixing screws 1. The fastening screw 1 is arranged at a distance from the profile 21, 121. The screw 1 can project in the envelope formed by the core 22, the upper flange 31, the lower flange 32, the upper flap 34, the lower flap 35 and a plane connecting the upper flap 34 to the lower flap 35 without being in contact with the profile 21, 121 housing the first insulation panel 23, 123. The total length of the rod of the screw 1 of fixing is chosen to completely cross the thickness of the second insulating panels 24, 124 and partially through the first insulating panels 23, 123. The density of the first insulating panels 23, 123 and the second insulating panels 24, 124 allows a manual screwing of the 1 fixing screw. In the presence of an additional layer 25, the small thickness thereof, allows the screwing. The first panels 23, 123 insulators are attached to the profiles 21, 121 themselves fixed to the fixed support 20. The second panels 24, 124 insulators are attached to the first panels 23, 123 insulating. The screw 1 is arranged substantially in the direction of the thicknesses of the insulating panels 23, 123, 24, 124. The screw 1 passes through the thickness of the second insulating panel 24, 124. The thread of the screw 1 is arranged at least partially in contact in the first insulating panel 23, 123. The head of the screw 1 is in contact with the outer surface 39 of the second panel 24, 124. The position of the fastening screws 1 through the first insulating panels 23, 123 and second panels insulators 24, 124 is, in the direction of the thickness of the assembly, at a distance from the profiles 21, 121 and the support 20. The fastening screws 1 are arranged vertically away from the connection regions of the first insulating panels 23, 123 and at a distance from the upper wings 31 and lower 32 of the profiles 21, 121. The fixing screw 1 is disposed horizontally in the direction of the thickness away from the upper flaps 34 and lower 35. These offsets reduce the conductivity thermally by fastening screws 1 and profiles 21, 121 through insulating layers. The composition of said fastening screws 1 provides low thermal conduction. The synthetic material composition may comprise plastics and / or composites, for example, polypropylene. After screwing the fixing screws 1, and as shown in Figure 2, the second insulation layer may be supplemented by an additional wall 40. The wall 40 may for example be solid, fireproof, fireproof, and / or essentially aesthetic function. The additional wall 40 is in contact with the axial ends of the fins 6 of the screw 1. The fins 6 of height A provide a substantial gap between the outer surface 39 of the second insulating panel 24 and the additional wall 40. This gap forms a blade of air. The air gap, such as for example a ventilation gap may have a thickness of at least 10 mm The presence of a layer of air reduces condensation within the assembly. The assembly can be obtained by adding a new insulation layer, here the second insulating panels 24, on an existing insulation layer, here the first insulating panels 23. This allows an improvement in the general insulation of a building without dismantling the pre-existing insulation of it. In other words, the new insulation layer is fixed, with or without an additional layer 25, on the existing insulation layer. The fixing screw 1 is designed to be compatible with insulating panels 23, 24 of various compositions, in particular heterogeneous and / or different densities, for example between 10 and 300 kg / m 3. The second insulating panels 24 may be of substantially identical composition to that of the first insulating panels 23 or be of substantially different composition. The second insulating panels 24 may be worn, for example free from another mass. Thus, in the presence of an additional heavy wall 40, the latter can be fixed to the rest of the assembly without transmitting the load of its weight to the second insulating panels 24. A supplementary heavy wall 40 can be attached to the profiles 21 by via fasteners passing locally through the second panels 24 without supporting it. In this case, the profiles 21 are load bearing and the second panels 24 are worn. The fixing screws 1 and the mounting system make it possible to considerably improve the thermal and acoustic insulation of buildings inexpensively. Re-design of existing parts such as profiles or insulation boards is not necessary. In particular, existing plants and machines for the manufacture of metal profiles and insulation panels, for example, are retained. The addition of a new layer of insulation preserves the old insulation layer. The addition of the additional insulating layer is fast and inexpensive. The speed and ease of attachment of the new insulating layer has advantages for the manufacturers of the various elements of the assembly as well as for the operators assembling these elements. An attachment screw 1 for insulating panels is shown in FIG. 3. The fastening screw 1 comprises a head 2 and a rod 3. The head 2 comprises a circular plate 12. The circular plate 12 includes a flat bearing face 4, also referred to as "flat under head" and an opposite face 5 to the bearing surface 4. The flat bearing surface 4 is intended to come to rest on an insulating panel. The flat bearing face 4 is axially oriented towards the rod 3. The opposite face 5 supports a drive fin 6. The driving vane 6 extends substantially perpendicular to the bearing face 4 and in an axial direction opposite to the rod 3. The driving vane 6 is intended to serve as a bearing surface for example for at least two fingers of an operator applying a tightening torque to the fastening screw 1. The screwing of the fastening screw 1 can therefore be manual. The screw 1 is made in one piece, for example by molding a synthetic material, for example of the plastic and / or composite type, such as polypropylene. The rod 3 extends substantially perpendicular to the circular plate 12 from its center and in a direction opposite to the fin 6. The rod 3 comprises an elongated body 7 extending axially from the head 2 to a tip 8. The tip 8 is disposed at the end of the body 7 opposite the head 2. In the example described here, the body 7 is substantially cylindrical. Alternatively, the body 7 may be substantially frustoconical. The tip 8 is sharp pointed. The tip 8 comprises recesses whose edges form leading edges to facilitate screwing and simultaneous drilling. The body 7 of the rod 3 comprises, here, splines 11. In a variant, the body 7 has an outer surface that is substantially of revolution. The fixing screw 1 comprises at least one helical thread 9. The helical thread 9 is supported by the rod 3. The helical thread 9 can be supported by the body 7 or the tip 8 or by the body 7 and the tip 8, cf. Figure 3. The helical thread 9 is axially distant from the head 2. Figure 4 shows a fastening screw 1, according to another embodiment, viewed from the side. A main axis X is here represented in dashed lines. Unless otherwise stated, the term "axis" refers to this main X axis. The arrow referenced Y represents the screwing direction of the fastening screw 1. This direction of screwing Y corresponds here to a rotation of "clockwise" direction, which corresponds to the direction of screwing conventionally used. The circular plate 12 supports, in the example described here, on its opposite face 5 two fins 6 extending in the radial direction on either side of the axis X. The two fins 6 extend axially up to at a distance A from the opposite face 5. The circular plate 12 has a diameter D of 50 to 80 mm and a thickness G of 1 to 3 mm. The elongate body 7 of the rod 3 has an axial length B extending from the flat bearing face 4 to the tip 8. The elongated body 7 of the rod 3 has a diameter F, here substantially constant along the direction axial. The height of the splines 11 is not taken into account here to determine the diameter F of the body 7, between 6 and 10 mm.

The tip 8 of the rod 3 has an axial length C. The sum of the axial length B of the body 7 and the axial length C of the tip 8 corresponds to the length IJi [of the rod 3. The sum of the length Lr of the rod 3, the thickness G of the circular plate 12 and the distance A between the opposite face 5 and the axial end of the fins 6 define the total length Lv of the screw 1. The tip 8 is here substantially frustoconical shape and has a half-angle M at the top, cf. Figure 4. The helical thread 9 is inscribed in an envelope 18 shown in dashed lines. The envelope 18 is, in the example described here, of substantially frustoconical shape. In one embodiment, a portion of the envelope 18, located on the side of the head 2, may be substantially cylindrical, as shown in dashed lines in FIG. 3. In other words, the edges of the helical thread 9, in a sectional view such as that of Figure 4, are aligned for each side of the X axis. In the example shown here, the envelope 18 and the tip 8 have a common vertex. The half-vertex angle of the envelope 18 is referenced N. Alternatively, the vertices of the tip 8 and the envelope 18 are distinct. In another variant, the envelope 18 comprises a substantially cylindrical portion. The diameter H of the helical thread 9 is defined as the diameter of the envelope 18 for a given axial position. In other words, the envelope 18 in a plane substantially perpendicular to the axis X defines a circle of diameter H. In the case represented here by a frustoconical envelope 18, the diameter H of the thread 9 varies linearly as a function of the position The diameter H is increasing towards the head 2. In the case of a substantially cylindrical envelope portion 18, the diameter H is substantially constant. The helical thread 9 extends axially over a length referenced I. The pitch of the helical thread 9 is here referenced P. The pitch P is greater than 8 mm and preferably greater than 15 mm or even 25 mm. As shown in dashed lines in FIG. 4 and visible in Figures 7 to 12, the fastening screw 1 comprises a hollow cavity 10 for rotating drive. The hollow cavity 10 extends axially from the opposite face 5 to a portion of the body 7 supporting the net 9. The recess 10 is of non-circular section, for example hexagonal, to allow a drive in rotation of the screw 1 fixing by a suitable screwing tool. In the case of a variant comprising recesses in the tip 8, as described in Figure 3, the hollow cavity 10 may be open into the recesses. In the case of the presence of a fingerprint 10 screw, or fins 6 are arranged to leave a passage for said screwing tool. The body 3 comprises a hollow portion.

In one embodiment shown in FIG. 4, the screw 1 comprises two fins 6 extending in a radial direction on either side of the axis X of the rod 7. The fins 6 extend axially from the opposite face 5. The fins 6 are substantially coplanar. Alternatively, shown in Figures 7 to 10, the fins 6 may be curved about axes parallel to the axis X. Two fins 6, in section along a plane perpendicular to the axis X, then take the form of a Flattened. The curved shape of the fins 6 can allow a better fit of shape, more ergonomic, with the fingers of the operator for manual screwing. Each fin 6 has a thickness of the order of 1 to 3 mm. The remainder of the opposite face 5 is substantially planar. The space left empty around the fins 6, beyond the opposite face 5 along the main axis X, forms recessed areas 41 complementary to the fins 6. The recessed areas 41 allow the passage of screwing tools and / or fingers of an operator. In two other embodiments, shown in Figures 11 and 12, the fins 6 occupy most of the angular zone of the head 2 along the main axis X, for example of the order of 175 ° each. The rest of the angular zone of the head 2 comprises recesses 14 in the circular plate 12. In other words, the circular plate 12 comprises recesses 14, the material of the circular plate 12 forming the periphery of said recesses 14 constitutes the fins 6. The bore of the recesses 14 serves as a bearing surface for screwing. The recesses 14 open into the opposite face 5. The recesses 14 allow the insertion of a tip of screwing tool or fingers to bear on the bore of the recesses 14, that is to say the fins 6, and apply a torque of screwing. The recesses 14 are, here, through and open into the bearing face 4. Alternatively, the recesses 14 are blind and open only on the opposite face 5. The shape of the recesses and their opening surface are chosen to allow the screwing. In the example described here, the recesses 14 take an oblong curved shape similar to the shape of the fins 6 of FIG. 7. The presence of recesses 14 allows a saving of material during the manufacture of the screw 1. In a variant, the recesses 14 may occupy a large angular space, for example of the order of 350 ° in total, while the fins 6 occupy a space of the order of 10 ° in total. The head 2 then takes the form of a ring connected to the rod 3 by fins 6 arranged substantially along radii of the circular plate 12.

The embodiment of FIG. 11 comprises a substantially hexagonal screw-in footprint. The embodiment of FIG. 12 comprises a rod 3 including a hollow portion formed by a substantially cylindrical recess 40. The cylindrical hollow portion 40 may be extended or not by a screw-in imprint 10.

The bearing face 4 of the head 2 is provided with bosses 13 so as to brake the unscrewing. The bosses 13 here take the form of protruding tips or cones from the bearing face 4. The bosses 13 are distributed over the circumference of the bearing face 4 at a distance from the rod 7. In a variant shown in FIGS. and 6, the bosses 13 are asymmetrical with respect to a plane passing through the axis X. The bosses 13 may have different slopes in the direction of screwing Y and in the opposite direction of unscrewing. In this way, the bosses 13 comprise a braking surface 31 at the unscrewing of significant slope relative to the bearing surface 4. During screwing, the bosses 13 have penetrating surfaces 32 of small slope relative to the surface of 4. In other words, the bosses 13 are arranged to give the fixing screw 1 a higher coefficient of friction in a direction of unscrewing with respect to a screwing direction Y. The bosses 13 brake the unscrewing. In a variant, represented in FIGS. 7 to 10, the braking surface 31 is substantially perpendicular to the bearing surface 4.

In another variant, the screw 1 comprises recesses 14 and bosses 13 mutually aligned in the direction of the main axis X. In this variant, the recesses 14 and the bosses 13 can be formed simultaneously for example by a localized repoussage of the material of the circular plate 12 from the opposite face 5 towards the bearing face 4.

Fastening screws 1 whose function is to ensure the assembly of insulating panels of relatively low average density, for example between 10 and 300 kg / m 3, and subjected to relatively low stripping stresses, the developed length of the net. 9 helical may be relatively small compared to fixing screws in the field of fastening wood panels or metal for example. The fixing screw 1 is designed to be screwed by hand, that is to say without special screwing tool. As a result, the final tightening position must be attained by a limited number of turns. The Applicant has therefore determined that the pitch P of the helicoidal thread 9 is greater than 8 mm, and preferably greater than 15 mm. For use in panels of very low density, for example less than 50 kg / m 3, the pitch P may even be greater than 25 mm The Applicant has in particular measured that such a screw 1, used in a system as described above, admitted a torque of between 0.2 and 2.0 Nm in rock wool from average density of 50 kg / m3 or in polyurethane (PUR) or polyisocyanurate (PIR). The fastening screws 1 have a length to diameter ratio substantially greater than the conventional screws. In particular, the body 7 of the rod 3 has a length B to diameter F ratio greater than 20. In order to allow a screwing involving a large translation for a small rotation while passing through thick insulating panels, the screw 1 of The invention may take the form of a kit for mounting a second insulating panel on a first insulating panel comprising at least a second insulating panel and at least one insulating board. a fixing screw. The invention may take the form of a method of fixing a second insulating panel to a first insulating panel. This method comprises manually screwing, or using a tool adapted to a hollow screw cavity, the screw. The screw is then self-tapping through the second insulating panel to cross, from one side to the other, the entire thickness of the second insulating panel. In a second phase of the screwing, the thread of the screw out through the inner surface of the second insulating panel and engages in the first insulating panel by fitting into the first insulating panel by its outer surface. At the end of screwing, the support face of the head of the screw comes to bear against the outer surface of the second insulating panel.

The invention is not limited to the examples of the method and apparatus described above, only by way of example, but encompasses all the variants that can be envisaged by those skilled in the art within the context of the claims below. after.

Claims (14)

REVENDICATIONS1. Screw device (1) for fixing insulating panels CLAIMS1. Screw device (1) for fixing insulating panels together, said screw (1) being produced in one piece of synthetic material and comprising a head (2) and a rod (3), the head (2) comprising a flat bearing face (4) on one of said insulating panels, an opposite face (5) to the bearing face (4) provided with at least one driving fin (6), said fin (6) extending to a distance (A) selected from the opposite face (5), said distance (A) being greater than 10 mm, the rod (3) comprising an elongated body (7) extending from the head (2) and substantially perpendicularly at the bearing face (4), a tip (8) disposed at one end of the body (7) opposite the head (2), and at least one helical thread (9), the helical thread (9) extending at least over a portion of at least one of the tip (8) and the body (7) and being remote from the head (2), the helical thread (9) having a diameter (H) increasing towards the head (2), the queue t (9) helicoidal comprising a portion having a frustoconical casing (18), the pitch (P) of the helical thread (9) being greater than 8 mm. 2. Device according to claim 1, comprising a hollow cavity (10) for rotating drive. 3. Device according to claim 2, wherein the hollow cavity (10) extends axially to a portion of the body (7) supporting the net (9). 4. Device according to one of the preceding claims, wherein the body (7) of the rod (3) comprises splines (11). 5. Device according to one of the preceding claims, wherein the body (7) of the rod (3) has a ratio length (B) to diameter (F) greater than 20. 6. Device according to one of the preceding claims, wherein the pitch (P) of the thread (9) helical is greater than 15 mm, preferably 25 mm. 7. Device according to one of the preceding claims, wherein the bearing face (4) of the head (2) is provided with bosses (13) braking the unscrewing, the bosses (13) being asymmetrical with respect to a plane. of section passing through an axis (X) of the rod (7) so as to confer a higher coefficient of friction in a direction of unscrewing with respect to a screwing direction (Y). 8. Device according to one of the preceding claims, comprising two fins (6) extending in the radial direction on either side of an axis (X) of the rod (3) and extending axially up to at said selected distance (A) from the opposite face (5). 9. Device according to one of the preceding claims, wherein the body (7) comprises a hollow portion. 10. A building wall insulation system comprising at least a first insulating panel (23) and at least one second insulating panel (24) having a density of between 10 and 300 kg / m3, mutually superimposed in the common direction of their thicknesses and interconnected by at least one screw (1) according to one of the preceding claims, the screw (1) being arranged substantially in the direction of the thicknesses of the insulating panels, a portion of the rod (3) passing through the thickness the second panel (24), the net (9) being at least partially disposed in the first panel (23) and the bearing surface (4) being in contact with an outer surface (39) of the second panel (24) . 11. The system of claim 10 further comprising an additional wall (40) resting on at least one fin (6) of the screw (1) so that an air layer of thickness (A) non-zero is formed between the additional wall (40) and the outer surface (39) of the second panel (24). 12. System according to one of claims 10 and 11, wherein the first panel (23) insulating is embedded in a profile (21) and maintained in the profile (21) by a flap (34) of the profile (21), the second insulating panel (24) being attached to the first insulating panel (23) by the screw (1) spaced apart from the profile (21). 13. Kit for mounting a second insulating panel (24) on a first insulating panel (23) comprising at least one second insulating panel (24) having an average density of between 10 and 300 kg / m 3 each and a screw (1) ) of fixing according to one of claims 1 to 9, the second insulating panel (24) being intended to be fixed on a first insulating panel (23) so that the first insulating panel (23) and the second insulating panel (24). ) are mutually superposed in the common direction of their thicknesses and linked together by the screw (1), the screw (1) being intended to be screwed substantially in the direction of the thicknesses of the insulating panels, a portion of the rod (3) passing through the thickness of the second panel (24) so that the thread (9) is engaged in the first insulating panel (23) and the bearing face (4) is in contact with an outer surface (39) the second panel (24). 14. A method of fixing a second insulating panel (24) to a first insulating panel (23), characterized in that it comprises the screwing of a fastening screw (1) according to one of claims 1 to 9 to through the thickness of a second insulating panel (24) and engaging the helical thread (9) of the screw (1) in a first insulating panel (23).