ATTACHMENT DEVICE

Description

[0001] The present invention relates to an attachment device for securing roofing material to a supporting roof structure, said roofing material comprising a tighting layer formed by sections overlapping each other at edge portions and including meltable bitumen or the like to weld together the sections within the overlapping edge portions, said attachment device consisting of a plate, preferably of metal, and a screw or the like extending through the plate and designed to be anchored in the roof structure before overlapping is effected, whereby the plate presses against the section of the tighting layer to secure it to the roof structure, said plate being oblong with two longitudinal side portions, two transverse end portions and a transverse mid-portion with a central hole for said screw, a large, uninterrupted opening being arranged on each side of the mid-portion.

[0002] To effect external insulation of a roof construction, the insulating layer must be secured to the supporting roof structure which may consist of concrete, light concrete, wood or sheet-metal. The insulating layer is covered by a web-shaped tighting, i.e. weatherproof, layer provided with bitumen, applied in sections and welded together at the overlapping edge portions. Oblong rectangular plates are placed along a free edge portion of a section and secured with screws in the supporting roof structure, thereby securing the tighting layer and the insulation together to the roof structure. The edge portion and the plates attached therein are then overlapped by an edge portion of the next section and hot air is supplied to melt the bitumen in the tighting layer so that the edge portions are welded together when the bitumen again has become solid. The overlap joint thus consists of a lower edge portion of a first section and an upper edge portion of a second section. According to current regulations the part of the overlap joint free from the plates must have a minimum width which, according to Swedish regulations, is currently 8 cm. In order to fulfil the requirement of material saving, i.e. the smallest possible width of the overlap joint, the plates are placed as close to the edge line of the edge portion as possible. The screw in each plate is then the weak link in the construction so that stress in the first section results in a break in the edge portion of the section between the screw and its said edge line, this break in turn causing additional breaks at other points of the overlap joint. One proposal for solving this problem has been to make the overlap joint somewhat wider by placing the plates somewhat further, e.g. 1.5-2 cm, from said edge line so that a corresponding inner portion is formed where the two edge portions can be joined together. However, this proposal entails increased material costs as a result of the wider overlap joints. Another problem with the plates used so far is that the tighting layer does not engage with the plates during welding and instead the plates will form weak points in the overlap joint enclosing the plates. Also in this case it has been necessary to make the overlap joints wider in order to reduce said problem, and this has necessitated the use of more material for the tighting layer. The size of the plates has also been limited in order not to aggravate the problem of weak points, but such a reduction in size leads in turn to diminished strength of the tighting layer within the overlap joint.

[0003] From US-A-4,282,050 it is known a fastening device which is used for mechanical anchoring an impervious cladding. The fastening device comprise a rectangular stiff plate which at each end is provided with gripping claws and a central hole for a screw or the like. Said claws are formed by stamping the plate. The stamping step for forming the claws also result in two large openings at the ends of the plate.

[0004] The object of the present invention is to provide a plate enabling sufficient strength to be achieved in the overlap joint, even at the inner part located between the plate screw and the inner section edge, while yet at the same time allowing the overlap joint to be narrow as desired to reduce the material consumption, and also enabling the edge portions of the sections of the tighting layer to be welded together without weak points arising in the welded overlap joints, and also in this case the use of narrower overlap joints and consequently savings in the material used for the tighting, i.e. weatherproof, layer.

[0005] The attachment device according to the invention is characterized in that the side portions are indented so that the width of the plate is at least 25%, preferably at least 30%, less at the mid-portion than at the end portions in order to provide functional side recesses outside each side portion, whereby the plate being arranged to be mounted adjacent or close to an inner edge of the lower edge portion, and the edge portions also being brought into contact with each other via said side recesses in order to provide an adhesion area primarily between the plate and said inner edge; that said openings together have an area that is at least 40%, preferably at least 45%, and at most 50% of the total area of the plate and being arranged to permit the edge portions to be welded together even inside the plate via the openings so that the plate is integrated with the edge portions to form a tight overlap joint; and that the plate has a flexural resistance of at least 750 N about its longitudinal axis.

[0006] The invention will be described in more detail with reference to the accompanying drawings.

[0007] Figures 1 and 2 show a side view and top view, respectively, of a plate in an attachment device according to a preferred embodiment of the invention.

[0008] Figure 3 shows a top view of an overlap joint in a tighting or weatherproof layer, where attachment devices according to the invention are enclosed and integrated with the edge portions of two sections of the tighting layer.

[0009] Figure 4 shows a section along the line IV-IV in Figure 3.

[0010] Figures 1 and 2 show a plate, oblong in shape, with two transverse end portions 1, 2, two longitudinal side portions 3, 4 and a transverse mid-portion 5. The end and side portions 1, 2, 3, 4 are relatively narrow, seen in the plane of the plate, without being deformable by normal stresses. Furthermore, the mid-portion 5 is relatively narrow and has a central hole 6 for a screw or the like. Each longitudinal side portion 3, 4 is provided with a ridge 16 and corresponding groove 7, thereby ensuring that the plate has sufficient bending resistance with minimal width of the side portions 3, 4. Uninterrupted openings 8, 9 are provided on each side of the mid-portion 5, these openings being defined by the end portions 1, 2, the side portions 3, 4 and the mid-portion 5. By "uninterrupted opening" is meant that the opening is unitary and thus entirely free of the construction material of the plate, in order to allow free passage. Said portions 1-5 have a minimal width, but are sufficiently wide to ensure that the plate is completely rigid in all directions, while at the same time the two openings 8, 9 are suitably as large as possible. The two openings 8, 9 together thus have an area that is at least 40% and preferably at least 45%, but at most 50% of the total area of the plate. The plate has a flexural resistance of at least 750 N measured at the centre of the plate with the end portions 1, 2 as support points, this being ensured by profiling the relatively narrow side portions 3, 4 by means of said grooves 7.

[0011] The longitudinal side portions 3, 4 of the plate are indented towards the centre so that the plate has functional side recesses 17, 18 on each side of the central hole 6. The width of the plate is thereby considerably less at the transverse mid-portion 5 than at the transverse end portions 1, 2. To achieve the requisite contact surface for the overlapping edge portions 10, 13 of the sections, the width of the plate is at least 25%, preferably at least 30%, less at the mid-portion 5 than at the end portions 1, 2. The plate is symmetrical, as shown in the drawings, thereby preventing incorrect assembly and the roof-layer needs no instructions as to which long side shall be turned towards the inner edge of the section. The plates are placed within an edge portion 13 of a section 11 of the tighting or weatherproof layer, after which they are secured with screws 12 or the like passing through the central hole 6 of the plate and screwed into the supporting roof structure. The tighting layer normally covers an insulating layer. The edge portion 13 is then overlapped by an edge portion 10 of an adjacent section 14 of the tighting layer so that an overlap zone 15 is formed in which the plates are completely enclosed. The overlap zone 15 may have a width of 12-14 cm. The tighting layer contains bitumen or the like which is caused to melt in the overlap zone 15 by applying hot air so that the two edge portions 10, 13 are caused to adhere to each other and are welded together to form a permanent joint when the bitumen or the like has solidified. Designing the plate with large openings 8, 9 ensures that the two edge portions 10, 13 are also in contact with each other through these openings 8, 9 and are thus welded together within the plate over sufficiently large inner adhesion areas to prevent them from releasing their grip on the inner edges of the plate. The plate is thus integrated with the overlapping edge portions 10, 13 and a stronger overlap joint is obtained which in turn further ensures that it is weatherproof. At the same time the end and side portions 1, 2, 3, 4 of the plate will take up loads over a relatively large area.

[0012] Designing the plate with relatively large side recesses 17, 18 ensures, as shown in Figure 4, that the two edge portions 10, 13 are also in contact with each other via these side recesses 17, 18 so that they are welded together over sufficiently large adhesion areas immediately outside the longitudinal side portions 3, 4 and particularly over the adhesion area obtained between the plate and the inner edge of the edge portion of the lower section, even if the widest parts of the plate are aligned with or immediately, e.g. 0.1-3.0 mm, inside said inner edge. Sufficient strength is thus also obtained at the inner part, which is located between the screw and the inner edge of the section, while yet at the same time a desired narrow overlap joint is obtained in order to reduce the material consumption. Since the strength is guaranteed, a tight or weatherproof overlap joint is also ensured within the areas for the plates.

[0013] The plate preferably consists of metal and its length is suitably twice its greatest width. In certain cases the plate may be of plastic.

Claims

1. An attachment device for securing roofing material to a supporting roof structure, said roofing material comprising a tighting layer formed by sections (14, 11) overlapping each other at edge portions (10, 13) and including meltable bitumen or the like to weld together the sections (11, 14) within the overlapping edge portions (13, 10), said attachment device consisting of a plate, preferably of metal, and a screw (12) or the like extending through the plate and designed to be anchored in the roof structure before overlapping is effected, whereby the plate presses against the section of the tighting layer to secure it to the roof structure, said plate being oblong with two longitudinal side portions (3, 4), two transverse end portions (1, 2) and a transverse mid-portion (5) with a central hole (6) for said screw (12), a large, uninterrupted opening (8, 9) being arranged on each side of the mid-portion (5), characterized in that the side portions (3, 4) are indented so that the width of the plate is at least 25%, preferably at least 30%, less at the mid-portion (5) than at the end portions (1, 2) in order to provide functional side recesses (17, 18) outside each side portion (3, 4), whereby the plate being arranged to be mounted adjacent or close to an inner edge of the lower edge portion (13), and the edge portions (10, 13) also being brought into contact with each other via said side recesses (17, 18) in order to provide an adhesion area primarily between the plate and said inner edge; that said openings (8, 9) together have an area that is at least 40%, preferably at least 45%, and at most 50% of the total area of the plate and being arranged to permit the edge portions (10, 13) to be welded together even inside the plate via the openings (8, 9) so that the plate is integrated with the edge portions (10, 13) to form a tight overlap joint; and that the plate has a flexural resistance of at least 750 N about its longitudinal axis.

2. An attachment device as claimed in claim 1, characterized in that each side portion (3, 4) is provided with a longitudinal ridge (16) and corresponding groove (7), thereby forming a profile increasing the flexural rigidity.

Ansprüche

1. Befestigungsvorrichtung zum Befestigen von Bedachungsmaterial auf einem Dachtragwerk, wobei das Bedachungsmaterial eine Dichtungsbahn umfaßt, die aus Abschnitten (14, 11) gebildet ist, die sich an Randbereichen (10, 13) überlappen und schmelzbares Bitumen oder dergleichen enthält, um die Abschnitte (11, 14) innerhalb der überlappenden Randbereiche (13, 10) zusammenzuschweißen, wobei die Befestigungsvorrichtung aus einer Platte, vorzugsweise aus Metall, und einer Schraube (12) oder dergleichen besteht, die durch die Platte hindurchsteht und dazu bestimmt ist, im Dachtragwerk befestigt zu werden, bevor das Überlappen durchgeführt wird, wobei die Platte gegen den Abschnitt der Dichtungsbahn drückt, um sie an der Dachstruktur zu befestigen, und die Platte länglich mit zwei Längsseitenabschnitten (3, 4), zwei Querendabschnitten (1, 2) und einem quer verlaufenden Mittelabschnitt (5) mit einer Mittelöffnung (6) für die Schraube (12) ausgebildet ist, wobei eine große, ununterbrochene Öffnung (8, 9) auf jeder Seite des Mittelabschnitts (5) angeordnet ist, dadurch gekennzeichnet, daß die Seitenabschnitte (3, 4) so eingebeult sind, daß die Breite der Platte mindestens 25%, vorzugsweise mindestens 30%, weniger am Mittelabschnitt (5) als an den Endabschnitten (1, 2) beträgt, um funktionale Seitenaussparungen (17, 18) an der Außenseite jedes Seitenabschnitts (3, 4) zu bilden, wobei die Platte so angeordnet ist, daß sie benachbart oder nahe einer Innenkante des unteren Randabschnitts (13) montiert wird, und die Randabschnitte (10, 13) ebenfalls über die Seitenaussparungen (17, 18) in Kontakt miteinander gebracht werden, um einen Haftbereich hauptsächlich zwischen der Platte und der Innenkante zu bilden; daß die Öffnungen (8, 9) zusammen eine Fläche haben, die mindestens 40%, vorzugsweise mindestens 45%, und höchstens 50% der Gesamtfläche der Platte beträgt, und so angeordnet sind, daß die Randabschnitte (10, 13) sogar im Inneren der Platte durch die Öffnungen (8, 9) zusammengeschweißt werden können, so daß die Platte in die Randabschnitte (10, 13) integriert ist, um einen dichten Überlappungsstoß zu bilden; und daß die Platte entlang ihrer Längsachse eine Biegesteifigkeit von mindestens 750 N hat.

2. Befestigungsvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß jeder Seitenabschnitt (3, 4) mit einem Längssteg (16) und einer entsprechenden Nut (7) versehen ist und somit ein Profil bildet, das die Biegesteifigkeit erhöht.

Revendications

1. Dispositif de fixation pour fixer un matériau de toiture à une structure de support de toit, ledit matériau de toiture comprenant une couche d'étanchéité formée par des sections (14, 11) se chevauchant mutuellement au niveau de parties de bord (10, 13) et comprenant du bitume fusible ou similaire pour assembler les sections (11, 14) mutuellement dans les parties de bord se chevauchant (13, 10), ledit dispositif de fixation étant constitué d'une plaque, de préférence en métal, et d'une vis (12) ou similaire s'étendant à travers la plaque et conçue pour être ancrée dans la structure de toit avant que le chevauchement soit effectué, de façon à ce que la plaque appuie contre la section de la couche d'étanchéité pour la fixer à la structure de toit, ladite plaque étant rectangulaire avec deux parties latérales longitudinales (3, 4), deux parties d'extrémité transversales (1, 2) et une partie transversale intermédiaire (5) comprenant un trou central (6) pour ladite vis (12), une grande ouverture continue (8, 9) étant formée de chaque côté de la partie intermédiaire (5), caractérisé en ce que les parties latérales (3, 4) sont découpées de sorte que la largeur de la plaque soit au moins 25 %, de préférence au moins 30 %, plus petite au niveau de la partie intermédiaire (5) qu'aux parties d'extrémité (1, 2) afin de former des évidements latéraux fonctionnels (17, 18) à l'extérieur de chaque partie latérale (3, 4), de façon à ce que la plaque soit formée pour être montée en position adjacente ou proche d'un bord intérieur de la partie de bord inférieure (13), et les parties de bord (10, 13) étant également amenées en contact les unes avec les autres par l'intermédiaire desdits évidements latéraux (17, 18) afin de fournir une zone d'adhérence principalement entre la plaque et ledit bord intérieur ; que lesdites ouvertures (8, 9) ont une superficie totale qui représente au moins 40 %, de préférence au moins 45 %, et au maximum 50 % de la superficie totale de la plaque, et sont agencée pour permettre aux parties de bord (10, 13) d'être assemblées les unes aux autres même à l'intérieur de la plaque par l'intermédiaire des ouvertures (8, 9) de sorte que la plaque soit intégrée aux parties de bord (10, 13) pour former un joint de recouvrement étanche ; et que la plaque a une résistance à la flexion d'au moins 750 N autour de son axe longitudinal.

2. Dispositif de fixation selon la revendication 1, caractérisé en ce que chaque partie latérale (3, 4) comprend une arête longitudinale (16) et une rainure correspondante (7), de façon à former un profil augmentant la rigidité à la flexion.

Drawing