EP0733140A1

EP0733140A1 - Large-area washer

Info

Publication number: EP0733140A1
Application number: EP95902124A
Authority: EP
Inventors: Helmut Österle; Stefan Baumgartner
Original assignee: SFS Industrie Holding AG
Current assignee: SFS Industrie Holding AG
Priority date: 1993-12-10
Filing date: 1994-12-05
Publication date: 1996-09-25
Anticipated expiration: 2014-12-05
Also published as: PT733140E; DK0733140T3; AU1109695A; DE59409244D1; DE4342260A1; EP0733140B1; ES2146305T3; DE4342260C2; WO1995016086A1; CA2178652A1; GR3033440T3; US5951225A; ATE191046T1

Abstract

PCT No. PCT/EP94/04036 Sec. 371 Date Jul. 26, 1996 Sec. 102(e) Date Jul. 26, 1996 PCT Filed Dec. 5, 1994 PCT Pub. No. WO95/16086 PCT Pub. Date Jun. 15, 1995In the large-area washer with an aperture for fastener means, there are engagement components on the surface in the fastening direction of the washer. The engagement components engage a cover strip that is to be fastened. The washer also has stiffeners in the form of beads. Unreinforced corner regions of the washer lie radially outside the stiffeners relative to the aperture and can be elastically resiliently bent about an imaginary line at an acute angle to two central axes of the washer. Engaging components may be formed in these corner regions.

Description

Large washer

The invention relates to a large-area washer with an opening for inserting a fastener, stiffening elements such as reinforcement indentations or beads and / or reinforcement elevations or ribs being formed on the washer.

Such washers, which are known from US 47 63 456 and US 47 87 188, are used for fastening single or multi-layer roofing membranes and / or an insulating layer on a solid substructure. In order to achieve a corresponding mounting of the covering roof membrane, tips are provided as engagement elements in the washer known from US 47 63 456, which drill into the roof membrane, and teeth are provided in the washer known from US 47 87 188. that do not pierce the roofing membrane, but only increase the friction between the washer and the roofing membrane. Relatively high forces arise between the roofing sheets and the underside of the washers, in particular when strong forces occur due to the corresponding suction load on the roofing sheet, which attempts to pull the roofing sheet out from under the fastener or under the washer.

Furthermore, it has always been found to be a problem that, with a corresponding suction load on the roofing membranes, these are practically lifted with a correspondingly large force in the axial direction of the fastener used. Since the large-area washers are of limited size, the corner areas of the washers, in particular, intervene relatively strongly in the web material. Especially when a firm hold is achieved between the underside of the washer and the roofing membrane and thus the roofing membrane cannot be pulled out from under the washer, there is a correspondingly greater load in the corner areas of the washer when the roofing membrane is lifted, so that it always it has happened again that precisely these corner areas of the washer cause damage to the roofing membrane.

In the known designs, care has always been taken to ensure that appropriate reinforcements or stiffening elements were present in the edge region in order to be able to distribute the force emanating from the fastener relatively reliably over a large area. In order to there is, however, at the same time the danger that the corner areas of the washer may press into the web to be fastened and damage it if the load is excessive.

The object of the present invention is therefore to create a large-area washer with which the damage to roofing sheets in the corner region of the washer can be avoided.

According to the invention, it is proposed that the corner areas of the washer be arranged outside the sections having the stiffening elements and that they can be elastically bent up to a certain load area by a line intended to be at an acute angle to the two central axes of the washer.

So if there is an excessive load on the roofing membrane due to suction forces and this is thus lifted from the insulation underneath, the corner areas of the washer have the option of moving in the elastic area in order to prevent damage to the roofing membrane. If there is really an excessive amount of force, it would also be conceivable, and this possibility is given that the corner regions deform plastically. As a result, at least one corresponding safety factor is provided, which also takes into account cases with special storm effects. Given the usual wind loads, the corner areas can bend elastically and then always return to their original position.

It is further proposed that a coating increasing the friction and / or protruding engagement elements be formed in the corner regions on the surface pointing in the fastening direction in order to improve the friction and / or the engagement. Since corresponding elements for improving the friction and / or the engagement are formed in these corner areas, the necessary friction or the necessary engagement between the underside of the washer and the upper side of the roofing membrane is always achieved even with a corresponding elastic bending of the corner areas maintain.

The present invention has made it possible to significantly improve precisely that area of the large-area washers which has repeatedly caused particular problems in the event of damage to the roofing sheets.

In a special embodiment, the bendable corner regions of the washer are formed in that the limitation of the stiffening elements runs at least in the corner areas of the washer at an acute angle to both mutually facing side boundaries. So just outside the stiffening elements, a flat, larger area is created, which can be elastically bent.

According to a special embodiment, it is provided that the stiffening element is designed as a reinforcing bead which surrounds the central opening in the washer and is circumferentially closed, which in the corner regions of the washer is at an acute angle to both central axes. This ensures that the stiffening element, viewed in the respective axial direction, comes close to the circumferential edge of the washer in order to properly distribute the fastening forces over the length or width of such a washer. At the same time, the possibility has also been created that the corner areas remain elastic and, so to speak, unstiffened.

An advantageous embodiment, especially in connection with the elastically bendable corner areas, is possible if the washer is rectangular or square in a manner known per se with rounded corners or as an ellipse. With these types of washers, there is always the risk of the corner areas being pressed in, whereby in the case of an ellipse, the transition area between the larger and the smaller arc section is meant.

In order to improve the engagement of the washer in the roofing membrane, it makes sense to provide a corresponding number of engagement elements. In the present invention, it is conceivable that engagement elements are formed both at the corner regions and within a section enclosed by a stiffening bead. Corresponding elements for improving the friction and / or the engagement can therefore be arranged distributed over a relatively large area, so that particularly high friction or good engagement between the washer and the roofing membrane is ensured.

In an expedient embodiment it is provided that the stiffening elements point counter to the fastening direction, the flat corner regions and the sections of the washer lying between the stiffening elements, with the exception of the region with the opening, being aligned in a common plane lying below the stiffening elements. This embodiment ensures a particularly good engagement of the engagement elements, since practically all engagement elements protrude downward from a flat support on the roofing membrane. This is possible because the stiffening elements are directed upwards from the main plane of the washer. In order to achieve a particularly good engagement between the washer and the roofing membrane, it is expedient if two or more than two engagement elements in the form of tips, prongs, projections or the like are provided in the corner regions of the washer, at least two of which or three such engaging elements are aligned in a row which runs parallel to the imaginary line for elastic bending of the corner regions. Should there be an elastic bending of such a corner area, there is always the guarantee that there will be a full engagement between the underside of the washer and the roofing membrane over the entire length, in accordance with the imaginary bending line, since those provided in a row Engagement elements are each aligned parallel to this intended bending line.

Another useful variant for a washer in the sense of the invention provides that it is made of a spring steel sheet. Particularly with such an embodiment, even when relatively high suction forces act on the roofing membrane, a large bending area can be achieved in the corner areas of the washer without the washer being plastically deformed.

Further features and special advantages are explained in more detail in the following description with reference to the drawings. Show it:

1 shows a section through an example of use of a large-area washer for fastening insulation layers and roofing membranes;

FIG. 2 shows the same application as in FIG. 1, but with corresponding forces acting on the roofing membrane;

Figure 3 is a large washer in plan view.

4 shows a section along the line IV-IV in Fig. 3.

Fig. 5 is a section along the line V-V in Fig. 3;

6 to 10 different embodiments of washers, each in a top view;

11 shows a section along the line Xl-Xl in FIG. 10. A large-area washer 1 is used to fasten an insulation layer 2 and a roofing membrane 3 covering this to a fixed substructure 4. A fastener 6, which in this case is designed as a screw, is inserted into a central opening 5. The roofing membrane 3 is attached in each case to an edge region 7, the edge region 8 of a subsequent roofing membrane 3 'covering the screwing positions. The roofing sheets 3 and 3 'are then glued or welded together in the area 9. As a result, the fastening itself has reached an area which is sealed off from the outside.

If, as can be seen in FIG. 2, the roofing sheets 3, 3 'are pulled upward by corresponding suction forces acting in the direction of the arrow 10, then corresponding forces act on the screw connection and in particular also on the washer 1 on. The area of the washer 1 on the right in the picture is pulled up in the direction of the arrow 11, whereas the area of the washer 1 on the left in the drawing sheet is pressed down in the direction of the arrow 12. This edge region of the roofing membrane 3 should now be held securely under the washer 1 in the event of such an extreme application of forces. In addition, it should be achieved that damage to the roofing membrane 3 is avoided as a result of this extreme indentation of the edge and corner regions of the washer 1 into the roofing membrane 3 simply because of the indenting corner regions.

An embodiment of a special washer 1 is explained in more detail with reference to FIGS. 3 to 5. In the case of a substantially rectangular washer 1, the opening 5 for receiving the fastener 6 is formed in a corresponding recess 4, the recess 14 serving to receive the head 15 of the fastener. A few engagement elements 13 are provided on the washer 1, which protrude on the underside of the washer 1 and thus ensure an increase in friction with respect to the underlying roofing membrane 3 or a corresponding engagement in this roofing membrane 3. In order to achieve a corresponding stiffening of the washer 1 and to bring the forces of the screw up to the respective edges in the area of the central axes, stiffening elements 16 are provided. 3 and 4, tabs 17 can be seen, which are punched out of an opening 20 and bent downward. These tabs 17 can serve as spacers if a large number of washers 1 are stacked one above the other for magazining, and in order to enable a twisting or shifting movement at all.

If the load case of such a large-area washer 1 is now considered, then it follows that the corner regions 21, with reference to the information in FIG. 2, both in the tensile region 11 and in the pressure region 12 strongly into the one below Lane 3 are pressed. The tensile region 11 is more heavily loaded because the section of the roofing membrane 3 located between the individual fastening points can also increase there.

According to the following description, it is now provided as an essential measure that the corner regions 21 of the washer are arranged outside the sections which have the stiffening elements 16, ie that the corner regions 21 have no particular stiffening by means of reinforcement indentations or beads and / or reinforcement elevations or ribs point. There is therefore the possibility that these corner areas 21 can be elastically bent up to a certain load area by a line L intended at an acute angle to the two central axes 22 and 23 of the washer 1. As long as forces occur that do not exceed the elastic bending area of the corner areas 21, the corner areas 21 are elastically flexible and can consequently follow changing load appearances. In the case of an extreme load case, there is still the possibility, as it were, that the corresponding corner region 21 can also plastically deform, that is to say as far as is bent around the imaginary line L that automatic return is no longer possible. Since corresponding engagement elements 13 are provided in each case in the corner region 21 of the washer 1, an equally good engagement between the underside of the washer 1 and the roofing membrane 3 is always ensured regardless of a possible elastic bending of the corner regions 21.

In this embodiment, the stiffening element 1 6 is designed as a reinforcing bead that surrounds the central opening 5 and is closed circumferentially. A small rectilinear section is provided on each of the two long sides, the stiffening element 16 running at an acute angle to both central axes 22, 23 in the direction of the corner regions, that is to say also in the direction of the narrow sides of the washer 1 lying opposite one another. The necessary distribution of force up to the edges, ie over the entire length and width of the washer, is ensured by the special arrangement of the stiffening elements 16, the corner regions 21 nevertheless remaining elastically bendable. In the embodiment shown in FIGS. 3 to 5, engagement elements 13 are formed only at the corner regions 21, that is to say outside of the section enclosed by the stiffening element 16. However, it is entirely conceivable, and in particular if the washer is of correspondingly large surface area, to also provide corresponding engagement elements 13 within a section lying from a stiffening element. Especially in the embodiment according to FIGS. 3 to 5 and also in some further embodiment variants, the stiffening elements 1 6 point upwards against the fastening direction, that is to say from the plane 24 through the main part of the washer. The flat corner regions 21 and the sections 25 between the stiffening elements 16 are aligned with the exception of the region of the depression 14 with the opening 5 in this common plane 24 lying below the stiffening elements 16.

From Fig. 3 it can be seen that three engagement elements 13 are provided in the corner regions 21, which are aligned in a row which runs parallel to the imaginary line L for elastic bending of the corner regions 21. This ensures a strong engagement of the washer in the roofing membrane to be fastened, especially at a short distance from the imaginary bending line. Of course, further engagement elements 13 can also be provided outside this row, which could also consist of only two such engagement elements 13, if this appears reasonable due to the size and the special design of the corner regions 21.

In the embodiment according to FIG. 6, an essentially square washer is provided, in which the stiffening elements are arranged in a similar form to that in FIG. 3, but with straight sections of the stiffening elements 16 on all edge regions. In this embodiment in particular, engagement elements 13 are also present in the section 25 provided within the stiffening elements 16.

In the embodiment according to FIG. 7, a washer which is approximately square in plan view is again provided, in which case the stiffening elements are also square, circumferentially closed, offset by 90 ° to the edge regions of the washer. This results in somewhat enlarged corner areas 21, so that the imaginary bending line L pushes even further towards the center. Such a design is particularly useful if sensitive roofing sheets are used and if a relatively large elastic deflection is possible due to the special material of the washer.

8 that a similar construction with elastically bendable corner regions 21 is also possible if the stiffening elements are not formed by beads or the like, but, as in this embodiment, from a convexly curved section of the washer . In this way too, the stiffening is brought from the fastening point up to close to the longitudinal or side edges of the washer 1, but the corner regions are nevertheless free of additional stiffening elements stay. These corner regions 21 can thus be elastically bent, with an additional measure being the fact that corresponding engagement elements 13 must be present in this region.

The embodiment according to FIG. 9 is a washer which is elliptical in plan view, the stiffening elements 16 in this case being arranged in a manner similar to that in the embodiment according to FIG. 3. If one speaks of corner areas 21 in the case of an elliptical washer, then this means the corresponding transition regions between the further and the narrower arches on the longitudinal and narrow sides of this washer.

10 and 11 it can be seen that the same arrangement is also possible with washers 1, in which the stiffening elements are designed as large indentations which also point in the direction of attachment. In such an embodiment too, corner regions 21 are formed which are provided with corresponding engagement elements 13, these corner regions being elastically bendable along imaginary lines L.

It is of course possible to use a wide variety of external shapes of large-area washers for the purpose described here. From the drawings it can be seen that the washers are rounded in their corner regions 21 with a relatively large arc. The measures described here would now make it possible to vary the radius of this corner formation, since the special indentation load, which has always been an important criterion, is essentially eliminated. A correspondingly smaller radius could therefore also be provided for the transition in the corner regions 21 of the washer 1.

The measures described here can be used for large washers, whether they are made of metal or plastic. Corresponding stiffeners can also damage the roofing membrane right up to the corner area of a washer, even in the case of the plastic version. Therefore, the design described here would be particularly advantageous, especially with plastic washers. In the case of a metal version, it would be advantageous to use a spring steel, with which the area in which the corner areas can be bent elastically could be significantly enlarged. There are practically no limits to the design of the stiffening elements, since these can be arranged or shaped independently of the measures described here. It is only necessary to always ensure that the corner regions 21 remain free of such stiffening elements so that they are designed to be elastically bendable. It would therefore be conceivable to provide any reinforcement indentations or beads and / or reinforcement elevations or ribs as stiffening elements. Especially when plastic is used, there will often be formation with corresponding ribs or formation of material accumulations, different material thicknesses, etc.

In the above description, it was assumed on the basis of exemplary embodiments that engagement elements are arranged or formed on the underside of the washer in the region of the elastically bendable corner regions. The elastically bendable corner areas are of course also advantageous for washers which have no engagement elements at all or if e.g. only in these corner areas no engagement elements are provided. The elastically bendable corner areas also bring significant new technical effects in themselves compared to the previously common designs of large-area washers, which represent a special advance.

No particular explanation has been given in the present description of the type of engagement elements. Engagement elements in the form of tips, prongs, projections or the like can be provided. However, it is also conceivable to provide engaging elements in the form of a corresponding coating on the underside of the washer, such a coating increasing the friction. With such a coating, different inclusions can of course also be provided for further increasing the friction.

In the example shown in FIGS. 1 and 2, a fastening in the hem area between two abutting roofing sheets is shown. An edge area is practically always attached here and the edge area of the next roofing membrane then overlaps this attachment point. The large-area washer described here would, however, with a correspondingly additional structural design, also be usable for fastening outside of a covered area, that is to say for free field fastening, in which case corresponding sealing elements would then of course have to be provided. For stress reasons alone and due to The possibility of elastic bendability of the corner areas results in the same optimal advantages in field fastening as in fastening in the hem region.

Claims

claims

1 . Large-area washer with an opening for inserting a fastener, stiffening elements such as reinforcing indentations or beads and / or reinforcing elevations or ribs being formed on the washer, characterized in that the corner regions (21) of the washer (1) outside of the stiffening elements. te (16) having sections (25) arranged and an acute angle to the two

Center axes (22, 23) of the washer (1) imaginary line (L) can be elastically bent up to a certain load range.

2. Washer according to claim 1, characterized in that a friction-increasing coating and / or protruding engagement elements (13) are formed in the corner regions (21) on the surface pointing in the fastening direction to improve the friction and / or the engagement.

3. Washer according to claim 1, characterized in that the outer edge of the facing stiffening elements (16) at least in the corner regions (21) of the washer (1) extends at an acute angle to both mutually facing side boundaries.

4. Washer according to claim 1, 2 or 3, characterized in that the stiffening element (16) is formed as a circumferentially closed, the central opening (5) in the washer (1) comprising reinforcing bead, which in the corner regions (21) the washer (1) is at an acute angle to both central axes (22, 23).

5. Washer according to one of claims 1 to 4, characterized in that the washer (1) is rectangular or square in a conventional manner with rounded corners or as an ellipse.

6. Washer according to claim 2, characterized in that engaging elements (13) are formed both at the Eckberei¬ chen (21) and within a section of a stiffening bead (16) enclosed section (25).

7. Washer according to one of claims 1 to 6, characterized in that the stiffening elements (16) point counter to the fastening direction, the flat corner regions (21) and the sections (25) lying between the stiffening elements (1 6) the washer (1), with the exception of the area with the opening (5), are aligned in a common plane (24) below the stiffening elements.

8. Washer according to one of claims 1 to 7, characterized in that in the corner regions (21) of the washer (1) two or more than two engagement elements (13) are provided in the form of tips, prongs, projections or the like, at least ¬ at least two or three such engaging elements (13) are aligned in a row which runs parallel to the imaginary line (L) for elastic bending of the corner regions (21).

9. Washer according to one of claims 1 to 8, characterized in that it is made of a spring steel sheet.