Method and retainer element for roof covering

Abstract: Retainer element (1) for fixing one or more plate-like building elements (20, 20', 20") to a carrier structure (21), the retainer element (1) comprising a holder part (2) and a support part (3) which engage each other, the holder part (2) being provided to hold one or more plate-like building elements and the support part (3) being provided to be fixed to the carrier structure (21), an orthogonal system being defined by three orthogonal axes intersecting each other perpendicularly in an origin, a first orthogonal axis being formed by a longitudinal axis according to the longitudinal direction of the retainer element and the two other orthogonal axes being formed by a height axis according to the height direction and a transverse axis according to the transverse direction of the retainer element, the holder part (2) being slidable with respect to the support part (3) along the longitudinal axis and being rotatable with respect to the support part (3) about the longitudinal axis, the holder part (2) and the support part (3) engaging each other by means of a joint which is located in the origin of the orthogonal system and which enables a rotation of the holder part (2) with respect to the support part (3) about each of both the other orthogonal axes.

Description: The present invention relates to a retainer element for fixing one or more roof-covering elements or façade plating elements to a carrier structure, the retainer element comprising a holder part and a support part supporting the holder part which engage each other in such a way that the support part prevents in use a downward movement of the holder part the holder part being provided to hold one or more roof-covering elements or façade plating elements and the support part being provided to be fixed to the carrier structure, an orthogonal system being defined by three orthogonal axes intersecting each other perpendicularly in an origin, a first orthogonal axis being formed by a longitudinal axis according to the longitudinal direction of the holder part and the two other orthogonal axes being formed by a height axis according to the height direction and a transverse axis according to the transverse direction of the holder part, the holder part being slidable with respect to the support part along the longitudinal axis and being rotatable with respect to the support part about the longitudinal axis. Such retainer elements are for example applied for constructing a roof covering or façade plating comprising a plurality of roof-covering elements or façade plating elements which are connected to each other and the carrier structure by means of the retainer elements. The roof-covering elements or façade plating elements can for example extend horizontally, slanting or in a waveform. They can have a constant or tapering width. The retainer elements are fixed onto the carrier structure at regular distances. The roof-covering elements or façade plating elements are for example profiled fold strips or plates having a substantially U-shaped cross section with two opposing standing edges. The standing edges each end in a substantially cylindrical curl with a substantially circular cross section. The U-shaped fold strip has a larger curl on one side and a smaller curl on the other. In order to fix the fold strips on the carrier structure, first the retainer elements are fixed on the carrier structure. Next, the smaller curl of a first fold strip is placed around the head of the holder parts of the retainer elements. Then, the larger curl of the adjacent fold strip is placed around the smaller curl of the first fold strip, after which both curls are mechanically bent around the retainer elements, for example by means of a folder machine which is known to the person skilled in the art. A retainer element for fixing one or more roof-covering elements or façade plating elements to a carrier structure is for example known from NL-C-1006110. The retainer element described in NL-C-1006110 comprises a holder part and a support part which engage each other. The holder part extends in height direction and comprises a head portion which is connected to a foot portion over a connecting body. The head portion is provided to be included in a curl of the roof-covering element or façade plating element. The foot portion of the retainer element is substantially cylindrical and is included in a substantially cylindrical groove in the support part, in which it is slidable in longitudinal direction. This groove is further shaped in such a way, that the holder part is rotatable with respect to the support part about a longitudinal axis, which extends centrally through the cylindrical foot portion and in longitudinal direction. The rotation of the holder part about the longitudinal axis is limited to an angle of maximum 15° in both directions, due to the body contacting the edge of the groove at an angle of 15°. Because metal roof-covering elements or façade plating elements expand or contract as a result of temperature differences, the connection is carried out in such a way that the curl of the roof-covering elements or façade plating element can slide over the head portion of the retainer element. If this capacity to slide is hampered, friction may cause undesired forces which may lead to moments, pulling the support part loose from the carrier structure. This risk mainly exists when the carrier structure is a brittle base. In the retainer element of NL-C-1006110, which is specially designed for fixing on a brittle base, the undesired forces can partly be overcome by the slidability of the holder part in longitudinal direction and its rotatability about the longitudinal axis. However, the retainer element described in NL-C-1006110 has the disadvantage that the tolerances for placing the retainer elements are very small and difficult to achieve, so that a special training is required in order to be able to correctly place the retainer elements. This is due to the requirement that the longitudinal direction of the holder part substantially has to coincide with the longitudinal direction of the curl of the roof-covering element or façade plating element. If the accuracy of fixing the retainer element on the carrier structure is insufficient, for example due to inaccuracies or carelessness of the person skilled in the art, additional forces may occur during the sliding of the curl over the head portion. This may for example occur when irregularities are present on the carrier structure on the location where the support part is fixed, so that the longitudinal axis of the retainer element encloses an angle with the plane in which the roof-covering element or façade plating element mainly extends. This may also occur when the longitudinal axis of the holder part of the retainer element is insufficiently aligned with the longitudinal direction of the curl, so that the longitudinal direction of the holder part of the retainer element encloses an angle with the plane in which the upstanding edge of the roof-covering element or façade plating element extends. In both cases the longitudinal axis of the holder part will diverge from the longitudinal direction of the curl, which may lead to additional, undesired forces caused by friction as a result of the sliding of the curl over the head portion of the holder part. Furthermore, the diversion may cause the holder part to become clamped in the support part, so that the sliding and the rotation of the holder part in the support part may be hampered and further undesired forces may occur. These undesired forces may lead to moments which act on the support part and wrench it loose from the carrier structure. US-A-1,882,105 also describes a retainer element having a holder part and a support part. The holder part is connected to the support part by means of a ball joint. This ball joint allows movements in all directions parallel to the plane of the roof covering, which means that the holder part is slidable in longitudinal direction with respect to the support part and is rotatable about its londitudinal axis. In this way, the retainer element allows the roof covering to expand and contract in consequence of temperature differences and to move back and forth in consequence of wind stresses. It is an aim of the invention to provide a retainer element for fixing one or more roof-covering elements or façade plating elements to a carrier structure, with which the risk of the occurrence of undesired forces can be reduced. This aim is achieved according to the invention in that the holder part and the support part engage each other by means of a joint which is located in the origin of the orthogonal system, which joint comprises at least one protruding part and at least one groove which are provided to engage in such a way that and which enables a rotation of the holder part with respect to the support part about each of both the other orthogonal axes is enabled, and the removability of the holder part from the support part along the height axis is prevented. This means that the joint not only permits a sliding movement of the holder part according to the longitudinal axis and a rotation of the holder part about the longitudinal axis, but also a rotation of the holder part about the height axis and a rotation of the holder part about the transverse axis. When the joint enables a rotation of the holder part about the transverse axis, this has the advantage that, when the longitudinal axis of the holder part encloses an angle with the plane in which the roof-covering element or façade plating element mainly extends, the holder part can rotate about the transverse axis until the longitudinal axis is parallel to said plane. When the joint enables a rotation of the holder part about the height axis, this has the advantage that, when the longitudinal axis of the holder part encloses an angle with the plane in which the upstanding edge of roof-covering element or façade plating element extends, the holder part can rotate about the height axis until the longitudinal axis is parallel to said plane. As the joint of the retainer element of the invention enables a rotation about the height axis as well as the transverse axis, both advantages are combined. Due to the rotatability of the holder part about the height axis and the transverse axis, the longitudinal axis of the holder part can be better aligned with the longitudinal direction of the curl than with the known retainer element, so that the risk of occurrence of undesired forces can be reduced, which may lead to moments pulling the support part loose from the carrier structure. As a consequence, the tolerances for placing the retainer element may be larger, since the alignment of the longitudinal axis with the longitudinal direction of the curl can be less accurate than with the known retainer element. Furthermore, it is no longer necessary to very accurately mount the retainer elements in line, since the holder parts of subsequent retainer elements can align in such a way that they substantially form a line, if the diversions are not too large. This can facilitate the placement of the retainer element and remove the necessity of a special training of the person skilled in the art. As the risk of occurrence of undesired forces can be reduced with the retainer element of the invention and as furthermore the holder part is longitudinally slidable with respect to the support part, it is made possible to connect the plate-like elements in a fixed way with the head portion of the holder part, without providing slidability of the curl over the head portion of the holder part. In this way, the expansion or contraction of the roof-covering element or façade plating element merely causes a sliding movement of the holder part with respect to the support part. The sliding of the curl over the holder part does not take place. This has the advantage that the lever arm of the moment which is created during sliding and which acts on the support part, is reduced by a substantial length, since the sliding movement occurs at the bottom of the holder part in stead of at the top. This moment is reduced substantially by the shorter lever arm, so that the risk that the support part is pulled from the carrier structure by this moment can be further reduced. Furthermore, this can facilitate the fixing of the roof-covering elements or façade plating elements on the retainer elements, since it no longer has to be made sure that the roof-covering elements or façade plating elements can slide over the head portions of the retainer elements upon expansion or contraction. In the retainer element according to the invention, the joint comprises at least one protruding part and at least one groove which are provided to engage in such a way that the holder part is not removable from the support part along the height axis. The protruding part is preferably provided on the support part and the groove in the holder part. Alternatively, the protruding part may also be provided on the holder part and the groove in the support part. By means of the protruding part and the groove, the holder part and the support part can be coupled in a simple way. As the holder part is not removable from the support part in height direction, the retainer element according to the invention can resist forces which act on the retainer element in height direction of the holder part. In this way, it can be prevented that the roof-covering element or façade plating element comes loose from the carrier structure as a result of such force. Such forces may for example be cause by wind blowing over the roof-covering element or façade plating element and pulling the roof-covering element or façade plating element upwards by suction. In a first preferred embodiment, the joint is formed by two grooves extending substantially symmetrically on both sides at the bottom of the holder part and two protruding parts on the support part which are each provided with a rounded nipple, the nipples being directed towards each other and the grooves being provided to include the holder part between the grooves. Because the nipples are rounded, an amount of play is present between the support part and the holder part. Because of this play, the holder part is rotatable to both sides about the height axis, the longitudinal axis and the transverse axis, each time over an angle of for example 15° or more or less. The rotation about the height axis and the londitudinal axis is limited by the fact that, in the extreme position, the holder part is in such a way located between the nipples, that it contacts both. The rotation about the transverse axis is limited by the fact that, in the extreme position, the bottom side of the holder part contacts the support part. By the rotatability of the holder part about the height axis, the londitudinal axis and the transverse axis over 15° it is achieved that the longitudinal axis of the holder part is allowed to diverge up to 15° from the longitudinal direction of the curl, so that the placement requires less accuracy than with the known retainer element. In a second preferred embodiment, the joint is formed by a groove in the lower part of the holder part and a protruding part on the support part which is provided to be included in the groove. The protruding part preferably mainly has the shape of a sphere or an inverse truncate cone with a sphere segment as base plane. The protruding part may however also have any other shape deemed suitable by the person skilled in the art. In the case that the protruding part has the shape of an inverse truncate cone with a sphere segment as base plane, the groove is preferably formed between two arms which enclose the cone in such a way that an amount of play is present on both sides of the cone. This play enables the holder part to rotate about the longitudinal axis over an angle of for example 15° or more or less. In the case the protruding part is mainly spherically shaped, the groove is preferably formed between two arms which cylindrically enclose the protruding part, also with an amount of play for ensuring the rotatability of the holder part about the longitudinal axis. In both these cases the holder part is rotatable with respect to the support part about the height axis, the longitudinal axis, as well as the transverse axis, since the contact surface between the groove and the protruding part is spherically shaped. The rotation about the height axis can furthermore occur over 360°, so that upon placement the support part can be arbitrarily oriented about the height axis with respect to the longitudinal direction of the curl of the roof-covering element or façade plating element, which can further facilitate the placement of the retainer element. The embodiment in which the protruding part has the shape of an inverse truncate cone with a sphere segment as base plane further has the advantage that it is easy to achieve, since this shape corresponds to the shape of a screw with a convex head. Preferably, the protruding part on the support part is adjustable in height. In this way, the distance between the upper end of the holder part and the carrier structure can be adjusted and, consequently, also the distance between the roof covering and the carrier structure. This can for example be advantageous when an isolating layer is to be placed between the roof covering and the carrier structure. The holder part of the retainer element according to the invention is preferably provided with blocking means for preventing that the holder part slides off the support part. These blocking means are preferably located on both ends of the one or more grooves. In this way it can be prevented that the holder part comes loose from the support part, when the holder part is moved too far in one direction with respect to the support part. Furthermore, the holder part of the retainer element according to the invention is preferably provided with positioning means which fix the holder part with respect to the support part, the positioning means being detachable. These positioning means are preferably located on both sides of the middle of the one or more grooves. By means of these positioning means it can be made sure that the holder part takes a suitable position with respect to the support part, until the roof-covering element or façade plating element is mounted on it. As these positioning means are detachable, they do not hamper the movement of the holder part along the longitudinal axis with respect to the support part. They will become detached when the expansion of contraction of the roof-covering element or façade plating element causes a sliding movement of the holder part with respect to the support part. This invention further relates to a method for fixing one or more roof-covering elements or façade plating elements on a carrier structure, use being made of retainer elements according to the invention, the roof-covering elements or façade plating elements being provided with a curl on both sides, the method comprising the following steps: a) fixing each retainer element on the carrier structure by means of the support part, b) subsequently fixing the roof-covering elements or façade plating elements on the holder parts of the retainer elements, the curls of the roof-covering elements or façade plating elements being bent around the head portions of the holder parts, c) providing each roof-covering element or façade plating element with a single fixed point, in which the roof-covering element or façade plating element is connected to the carrier structure in a fixed way, the curls being bent around the head portions in such a way, that they are connected to the holder parts in a fixed way. With this method it can be achieved, that no friction forces occur anymore between the curls and the head portions, only between the holder parts and the support parts of the retainer elements. This has the advantage that the lever arms of the moments resulting from friction forces are considerably reduced. As a result, the risk that the support parts are pulled loose from the carrier structure can be reduced. The fixed connection between the curls and the head portions can be achieved in a way known to the person skilled in the art, preferably by means of a folding machine which is known to the person skilled in the art, or in a different way. Fixedly connecting with a folding machine means that the curls are in such a way bent around the head portions, that they are not slidable over them. The use of a folding machine for achieving a fixed connection has the advantage that no fixing means are needed such as for example bolts, nails or other fixing means. In the method according to the invention, each roof-covering element or façade plating element is provided with a single fixed point, in which the roof-covering element or façade plating element is fixedly connected to the carrier structure. By this fixed point one achieves that an expansion, resp. contraction of the roof-covering element or façade plating element will cause an increase, resp. decrease in length with respect to this fixed point. This means that the holder parts, on which the roof-covering element or façade plating element is fixed, after a subsequent expansion and an equally large contraction, will always substantially return to their original positions with respect to the support parts. In this way, it can be prevented that the roof-covering element or façade plating element is moved by subsequent expansions and/or contractions, which could involve a damaging of one or more retainer elements. The invention will be further elucidated by means of the description given below and the appended figures of preferred embodiments of the retainer element of this invention. Figures 1 and 2 respectively show a cross section and a longitudinal section of a first preferred embodiment of the retainer element according to the invention. Figures 3 and 4 respectively show a cross section and a longitudinal section of a second preferred embodiment of the retainer element according to the invention. Figures 5 and 6 respectively show a cross section and a longitudinal section of a third preferred embodiment of the retainer element according to the invention. Figure 7 shows in perspective how roof-covering elements or façade plating elements are fixed on a carrier structure by means of retainer elements according to the invention. Figures 8a and 8b show how the undesired moments are limited with the retainer element of the invention with respect to retainer elements of the prior art. The retainer element 1 of the invention, of which three embodiments are shown in figures 1 to 6, comprises a holder part 2 and a support part 3. The holder part 2 is provided for holding one or more roof-covering elements or façade plating elements 20 (figure 7) and the support part 3 is provided to be fixed on a carrier structure 21 (figure 7). An orthogonal system is defined by a longitudinal axis L, a transverse axis D and a height axis H, which intersect perpendicularly in an origin O. The longitudinal axis L is directed according to the longitudinal direction of the holder part 2 of retainer element 1. The transverse axis D is directed according to the transverse direction of the holder part 2 of retainer element 1. The height axis H is directed according to the height direction of the holder part 2 of retainer element 1. The holder part 2 and the support part 3 are coupled by means of a joint 10. This joint enables a sliding movement of the holder part with respect to the support part along the longitudinal axis L, and a rotation of the holder part with respect to the support part about the longitudinal axis L. This joint 10 further enables rotations of the holder part with respect to the support part about the transverse axis D and the height axis H. The holder part 2 preferably comprises a head portion 4 for holding roof-covering elements or façade plating elements of for example a roof covering. This head portion 4 is connected to a bottom portion 6 over a connecting body 5. The head portion has for example a shape as shown in figure 1, but may also have any other shape. The support part 3 comprises a foot 9 which is provided for fixing on a carrier structure. The joint 10 preferably comprises at least one protruding part 8, 13, 16 and at least one groove 7, 12, 14 which are provided to engage each other. In the embodiments shown in figures 1-6, the protruding part 8, 13, 16 is provided on the support part 3 and the groove 7, 12, 14 is located in the holder part 2. However, the protruding part may also be provided on the holder part 2, with the groove then being provided in the support part 3. The protruding part 8, 13, 16 is provided to be included in the groove 7, 12, 14, a small amount of play being present between the protruding part and the groove. The groove and the protruding part engage each other in such a way, that the holder part 2 is not removable from the support part 3 along the height axis H. By the play between the protruding part and the groove is achieved that the holder part 2 is slidable with respect to the support part 3 in longitudinal direction over the full length of the groove or a portion thereof. Because of the play being present, the holder part 2 is furthermore rotatable with respect to the support part 3 about the longitudinal axis L, the transverse axis D and the height axis H. These three rotary movements can each amount to 15° or more or less. The foot 9 of the support element 3 can have a flat or concave bottom side, the bottom side being that side which contacts the carrier structure after fixing the support part 3. By means of a concave bottom side (not shown) it is achieved that irregularities on the bottom side of the foot 9 and on the carrier structure can be included in the foot 9. In this way, the contact between the foot 9 and the carrier structure can be limited to the outer edge of the concave bottom side of the foot 9, which is known to the person skilled in the art as a general mechanical principle. This has the advantage that a stable contact surface can be achieved between the foot 9 and the carrier structure. If the contact surface were limited to one or more contact points formed by irregularities on the foot and the carrier structure, these irregularities would form pivot points, so that forces being exerted on the foot 9 would lead to a pivoting movement of the support part 3 about these pivot points. This could damage the support part 3. In short, this can be avoided by a concave bottom side of the foot 9. In the first preferred embodiment of the retainer element, which is shown in figures 1 and 2, the joint 10 is formed by two grooves 14 and two protruding parts 16. The two grooves 14 are located substantially symmetrically on both sides at the bottom of the holder part 2 in cross section. Preferably, they extend over the full length of the holder part 2. Each of these two grooves 14 is formed between each time two protrusions 15. In this embodiment, the support part 3 comprises two protruding parts 16, each having a rounded nipple 17 on their sides facing each other. The nipples 17 of the protruding parts 16 are directed towards each other. The grooves 14 of the holder part 2 are provided to include the holder part 2 between the nipples 17. In the coupled state of the holder part 2 and the support part 3, each nipple is thus located between each time two protrusions 15, so that the holder part 2 is not removable from the support part 3 along the height axis, but is however slidable along the longitudinal axis L with respect to the support part 3. As the nipples 17 are rounded, play is present between the grooves 14 is the holder part 2 and the nipples 17 of the support part 3. Because of this play, the holder part 2 can rotate about the longitudinal axis L, the transverse axis D and the height axis H, each time over for example 15° or more or less. The rotations about the longitudinal axis L and the height axis H are limited by the contact between the holder part 2 and both nipples 17 in the extreme positions. The rotation about the transverse axis D is limited by the contact between the bottom side of the holder part and the foot 9 of the support part 3 in the extreme position. In the second and third embodiments, respectively shown in figures 3 and 4 and figures 5 and 6, the joint 10 comprises a protruding part 8, 13 which extends along the height axis H with respect to the foot 9, and a groove 7, 12 which is located in the bottom part 6 of the holder part 2. In the second embodiment, shown in figures 3 and 4, the protruding part substantially has the shape of a sphere 13. The sphere 13 is connected to the foot 9 over a support 27. The sphere is included in a substantially cylindrical groove 12, which is located in the bottom part 6 of the holder part 2. The cylindrical groove is enclosed between two arms 11, which surround the sphere 13 in such a way, that also in this second embodiment the holder part 2 is not removable from the support part along the height axis H. As in the first embodiment however, the holder part 2 can slide over the full length of the groove 12 with respect to the support part 3. The gap between the arms at the bottom of the sphere is wider than the width of the support 27, which is connected to the sphere, so that play is present on this location for enabling the rotation of the holder part about the longitudinal axis L. The cylindrical shape of the groove 12 and the round shape of the sphere 13 make sure that the holder part 2 is rotatable about the longitudinal axis L and the transverse axis D with respect to the support part 3, each time over for example 15° or more or less. The rotation about the transverse axis D is limited by the contact between the arms 11 of the holder part 2 with the foot 9 in the extreme position. The rotation about the longitudinal axis L is limited by the contact between one of the arms with the support 27 in the extreme position. Because of the cylindrical shape of the groove 12 and the round shape of the sphere 13, the holder part 2 is furthermore rotatable with respect to the support part 3 about the height axis over 360°. In the third embodiment, shown in figures 5 and 6, the protruding part has the shape of an inverse truncate cone 8 of which the base plane is a sphere segment. The cone 8 is connected to the foot 9 over a support 27. The groove 7 is again formed between two arms 11, which surround the cone 8 in such a way, that the holder part 2 is not removable from the support part 3 along the height axis H. The shape of the protruding part 8 which is described here enables the same movements of the holder part 2 with respect to the support part 3 as in the second embodiment described in the former paragraph. In this case, the rotation about the longitudinal axis L is limited by the contact between one of the arms 11 with the cone 8 or the support 27 in the extreme position. The rotation about the transverse axis D is again limited by the contact between the arms 11 and the foot 9 in the extreme position. The rotation about the height axis H can again amount to 360°. This embodiment has the advantage that it can be established easily, as the shape of an inverse truncate cone having a sphere segment as base plane corresponds to the shape of a screw with a convex head. In the embodiments shown in figures 3 to 6, the protruding part 8, 13 is preferably adjustable in height. In this way, the distance between the head 4 of the holder part 2 and the carrier structure 21 can be adjusted and consequently also the distance between the roof covering 20 and the carrier structure 21. In the embodiment shown in figures 3 and 4, the adjustability in height can be achieved by providing the support 27 with screw thread at the bottom of the sphere 13. A notch 29 is provided in the top of the sphere, which for example has a hexagonal shape, so that the support 27 can be screwed more or less into the foot 9 by means of a hexagonal lever. In the embodiment shown in the figures 5 and 6, the adjustability in height can simply be achieved by screwing the screw 8, 27 more or less into the foot 9. After the height of the protruding part 8, 13 has been set to the desired height, this position is preferably blocked. This can for example occur by placing a hexagonal nut (not shown) on the support 27 as jam nut, which is screwed against the foot 9 after the height adjustment. In the first preferred embodiment of the retainer element 1 according to the invention, which is shown in figure 2, the holder part 2 is provided with blocking means 18 which prevent that the holder part 2 slides off the support part 3. These blocking means 18 are located on at least one and preferably on both ends of both grooves 14. Providing these blocking means 18 prevents that the holder part 2 comes loose from the support part 3, when the holder part 2 is moved too far in one direction with respect to the support part 3. Similar blocking means can also be provided in the second embodiment of figures 3 and 4 and in the third embodiment of figures 5 and 6. The holder part 2 of the retainer element of figure 2 is furthermore provided with positioning means 19 which fix the holder part 2 with respect to the support part 3. These positioning means 19 are provided to fix the holder part with respect to the support part, so that the placing of the retainer element 1 can be facilitated. The positioning means 19 are detachable, so that they do not hamper the expansion and contraction of a roof-covering element or façade plating element which is mounted on the retainer element 1. When the expansion or contraction of the roof-covering element or façade plating element causes a sliding movement of the holder part 2 with respect to the support part 3, the positioning means will be detached. By fixing the holder part 2 on a suitable position during the mounting of the roof-covering element or façade plating element, it is ensured that the holder part 2 can later on sufficiently move with respect to the support part 3 as a consequence of the expansion and contraction of the roof-covering element or façade plating element, without the holder part 2 sliding off the support part 3. Similar positioning means may also be provided in the second embodiment of figures 3 and 4 and in the third embodiment of figures 5 and 6. The holder part 2 and the support part 3 are preferably constructed in metal, more preferably in aluminium. Aluminium has the advantage that it has a low specific weight and shows a good strength. By constructing the holder part 2 and the support part 3 in aluminium, one achieves a retainer element 1 which is low in weight, so that the load of the carrier structure can be limited, and a retainer element 1 which shows sufficient strength to sustain the different loads exerted on it by the roof-covering element or façade plating element. The holder part 2 and the support part 3 may however also be constructed in any other material deemed suitable by the person skilled in the art. In a further embodiment of the retainer element 1 according to the invention, the support part 3 is at least partially constructed in an isolating material. The part which is constructed in an isolating material, is for example the complete foot 9 or an isolation cap mounted around the periphery of the foot 9. This part in isolating material forms an isolating separation between the holder part and the carrier structure. The isolating material can be thermally isolating, electrically isolating or both. By an electrical isolation is prevented that electrolytic corrosion occurs in the event of an electrical potential difference between the retainer element and the carrier structure. Furthermore, an electrical isolation can contribute to the fact that, when the plate materials are suitably grounded, a system for lightning protection can be formed with this roof covering. By a thermal isolation one prevents that cold bridges are created between the carrier structure and the retainer elements. The isolating material can for example be a plastic material, or any other isolating material known to the person skilled in the art. In figure 7 is shown how the roof-covering elements or façade plating elements 20 are fixed on a carrier structure 21 by means of retainer elements 1. The roof-covering elements or façade plating elements which are mounted on the retainer elements 1 are preferably fold plates 20. Such fold plates 20 are mainly U-shaped and have a substantially flat base plate 22 and first and second standing edges 23, 24 which oppose each other. Each of these standing edges 23, 24 ends in a curl 25, 26, which extends in longitudinal direction of the fold plate 20. These curls are substantially cylindrical grooves, which are tensioned around the head portions 4 of the retainer elements 1. The first curl 25 of the first standing edge 23 has a larger diameter than the second curl 26 of the second standing edge 24. In this way, it is achieved that the first curl 25 of a first fold plate 20 can be placed around a second curl 26" of an adjacent fold plate 20". The roof-covering elements or façade plating elements 20 are fixed on a carrier structure 21 of for example a roof of a building as follows. First, the retainer elements 1 are fixed on the carrier structure 21 by means of the support parts 3. This can for example be carried out by screwing or stapling the support parts 3 into the carrier structure 21, or in any other way known to the person skilled in the art. In a next step, a first roof-covering element or façade plating element 20 is mounted on the retainer elements 1. A second roof-covering element or façade plating element 20' is mounted next to the first plate-like element 20 by placing the first curl 25' of the second roof-covering elements or façade plating element 20' over the second curl 26 of the first roof-covering element or façade plating element 20. The second curl 26' of the second roof-covering element or façade plating element 20' is placed over retainer elements 1 on a next carrier 21. In this way, multiple roof-covering elements or façade plating elements are mounted on the retainer elements. Next, the curls 25, 26 are folded close by means of a folding machine known to the person skilled in the art, a curl 25 of larger diameter being folded close together with a curl 26 of smaller diameter. In a final step, each roof-covering element or façade plating element 20 is provided with preferably one fixed point. This means that for example one end of each roof-covering element or façade plating element 20 is fixed to the carrier structure 21. In this way, it is achieved that the expansion of each roof-covering element or façade plating element 20 will cause an increase in the length of this roof-covering element or façade plating element with respect to this fixed point. The holder parts 2 of the retainer elements 1 on which the roof-covering element or façade plating element 20 is fixed, are hereby moved in a direction away from the fixed point. In a similar way, a contraction of the roof-covering element or façade plating element 20 causes a sliding movement of the holder parts 2 in a direction towards the fixed point. As a consequence, by providing each roof-covering element or façade plating element 20 with a fixed point, it is achieved that the holder parts 2 will substantially return to their original positions with respect to the support parts 3 after an expansion and a subsequent evenly large contraction. In this way, it is prevented that the roof-covering element or façade plating element 20 is moved by subsequent expansions and/or contractions, by which one or more retainer elements could be damaged and the roof-covering element or façade plating element 20 could come loose from the carrier structure by a breakage of the coupling between the holder part 2 and the support part 3. Because the joint 10 enables a rotation of the holder part 2 with respect to the support part 3 about the longitudinal axis L, the transverse axis D and the height axis H, the placing of the retainer elements 1 can be conducted with higher tolerances than with the retainer elements known from the prior art. Because of the rotatability of the holder part 2, this can namely direct itself according to the longitudinal direction of the curl 25, 26 which is mounted on the head portion 2 of the holder part 2. Furthermore, because of the slidability of the holder part 2 with respect to the support part 3 along the longitudinal axis L, the undesired moments can be limited which occur as a result of friction forces which originate from the sliding of the roof-covering elements or façade plating elements, en which can pull the support part loose from the carrier structure. Because of the slidability, possible frictional forces namely occur in the joint 10 instead of at the head portion 4. This is illustrated in figures 8a and 8b. With retainer elements known from the prior art, a frictional force W occurs at the head portion 4. This frictional force W leads to an acting moment M o , which strives to pivot the support part 3 about a pivot point A at an end of the bottom side of the support part 3. This acting moment M o equals the product W.h 1 , in which h 1 is the lever arm or the distance between the pivot point A and the head portion 4 on which the frictional force W acts. A bolt 28, with which the support part 3 is fixed to the carrier structure 21, has to produce a counteracting moment M t order to cancel the acting moment M o . This counteracting moment M t equals the product T.h 2 , in which T is the pull force to be produced by the bolt 28 for the counteracting moment M t and h 2 is the lever arm of the pull force T or the distance between the pivot point A and the axis of the bolt 28. From M 0 = W.h 1 and M t = T.h 2 with the condition that M t ≥ M o , follows the condition T ≥ W.h 1 /h 2 In the retianer element of the invention, the frictional force W acts much lower, namely in the joint 10 instead of in the head portion 4, so that the lever arm h 1 ' is much smaller than h 1 . As a result, the pull force T' which the bolt 28 has to be able to produce with the retainer element of the invention is T' ≥ W.h 1 '/h 2 which means that T' is much smaller than the pull force T with the retainer element of the prior art. Reference list 1 retainer element 2 holder part 3 support part 4 head portion 5 connecting body 6 bottom part 7 groove 8 inverse truncate cone 9 foot 10 joint 11 arms 12 cylindrical groove 13 sphere 14 grooves 15 protrusions 16 protruding parts 17 nipple 18 blocking means 19 positioning means 20, 20', 20" fold plate 21 carrier structure 22 base plate 23, 24 standing edge 25, 25' first curl 26, 26" second curl 27 support 28 bolt 29 notch L longitudinal axis D transverse axis H height axis O origin W frictional force T, T' pull force h 1 , h 1 ', h 2 lever arm A pivot point M o acting moment M t counteracting moment

Claims: Retainer element (1) for fixing one or more roof-covering elements or façade plating elements (20, 20', 20") to a carrier structure (21), the retainer element (1) comprising a holder part (2) and a support part (3) supporting the holder part (2) which engage each other in such a way that the support part prevents in use a downward movement of the holder part the holder part (2) being provided to hold one or more roof-covering elements or façade plating elements and the support part (3) being provided to be fixed to the carrier structure (21), an orthogonal system being defined by three orthogonal axes intersecting each other perpendicularly in an origin, a first orthogonal axis being formed by a longitudinal axis according to the longitudinal direction of the holder part (2) and the two other orthogonal axes being formed by a height axis according to the height direction and a transverse axis according to the transverse direction of the holder part (2), the holder part (2) being slidable with respect to the support part (3) along the longitudinal axis and being rotatable with respect to the support part (3) about the longitudinal axis, characterised in that the holder part (2) and the support part (3) engage each other by means of a joint which is located in the origin of the orthogonal system, which joint comprises at least one protruding part and at least one groove which are provided to engage in such a way that a rotation of the holder part (2) with respect to the support part (3) about each of both the other orthogonal axes is enabled, and the removability of the holder part (2) from the support part (3) along the height axis is prevented. Retainer element according to claim 1, characterised in that the joint is formed by two grooves at the bottom of the holder part, which grooves are, considered in cross section, located substantially symmetrically on both sides, and two protruding parts on the support part which are each provided with a rounded surface, the protruding parts being directed towards each other and being provided to be included in the grooves. Retainer element according to claim 1, characterised in that the joint is formed by a groove in a lower part of the holder part and a protruding part on the support part which is provided to be included in the groove. Retainer element according to claim 1 or 3, characterised in that the protruding part is mainly spherical. Retainer element according to claim 1 or 3, characterised in that the protruding part mainly has the shape of an inverse truncate cone of which the base plane is a sphere segment. Retainer element according to any one of claims 3-5, characterised in that the protruding part is adjustable in height. Retainer element according to any one of claims 1-6, characterised in that the holder part (2) is provided with blocking means (18) for preventing that the holder part (2) slides off the support part (3) in longitudinal direction. Retainer element according to any one of claims 1-7, characterised in that the holder part (2) is provided with detachable positioning means (19) which fix the holder part (2) with respect to the support part (3). Retainer element according to any one of claims 1-8, characterised in that the holder part (2) is constructed in aluminium. Retainer element according to any one of claims 1-9, characterised in that the support part (3) is constructed in aluminium. Retainer element according to any one of claims 1-10, characterised in that the support part (3) is at least partly constructed in a thermally and/or electrically isolating material, this isolating material forming an isolating separation between the holder part (2) and the carrier structure (21). Method for fixing one or more roof-covering elements or façade plating elements (20, 20', 20") on a carrier structure (21), use being made of retainer elements (1) according to any one of the previous claims, the said roof-covering elements or façade plating elements being provided with a curl (25, 25', 26', 26") on both sides, the method comprising the following steps: a) fixing each retainer element (1) on the carrier structure (21) by means of the support part (3), b) subsequently fixing the roof-covering elements or façade plating elements (20, 20', 20") on the holder parts (2) of the retainer elements (1), the curls of the roof-covering elements or façade plating elements (20, 20', 20") being bent around the head portions (4) of the holder parts, c) providing each roof-covering element or façade plating element (20, 20', 20") with a single fixed point, in which the roof-covering element or façade plating element (20, 20', 20") is connected to the carrier structure (21) in a fixed way, characterised in that the curls are bent around the head portions (4) in such a way, that they are connected to the holder parts (2) in a fixed way.

Inventors: BAECK ARTHUR GERARD M, BAECK, ARTHUR GERARD M.
Applicants: BAECK ARTHUR GERARD M, BAECK, ARTHUR GERARD M.
Application year: 2001
Main classification: E04D3
IPC codes: E04D3