WO1994024386A1

WO1994024386A1 - Large-surface, substantially rectangular washer

Info

Publication number: WO1994024386A1
Application number: PCT/EP1994/001076
Authority: WO
Inventors: Stefan Baumgartner; Helmut Oesterle; Beda Angehrn
Original assignee: Sfs Industrie Holding Ag
Priority date: 1993-04-16
Filing date: 1994-04-07
Publication date: 1994-10-27
Also published as: DE4312533C1; AU6565894A

Abstract

A large-surface washer (1) is normally used for securing insulating layers and, as needed, strips laid over them, the washer (1) having a center hole (5) for inserting the proper fastener. The thickness (C, F, E) of the washer (1) tapers from the center hole (5) to the delimiting edge (17, 18), with the angle (W) between the generatrices (34, 35) of the upper side (30) and the lower side (31) of the washer (1) remaining at least approximately the same in all possible section planes from the central hole (5). Particularly with a substantially rectangular washer, one can therefore be assured that in the region of the narrower dimensions there is sufficient thickness (F) to prevent a buckling of the washer under corresponding stress.

Description

Large washer, essentially rectangular in shape.

The invention relates to a large-area washer, which is essentially rectangular in shape, with a central opening for inserting a fastener for fastening insulation layers and, if appropriate, sheets covering these on a solid substructure.

Such washers are generally used when fastening single or multi-layer roofing membranes and / or an insulating layer to a solid substructure. There is always the requirement that, precisely because of the design as a large-area washer, the contact pressure can be transmitted to a relatively large area on the web to be fastened. It is also necessary that the washers have a corresponding rigidity so that the required contact pressure or force transmission is also possible on the outer edge areas of the washers.

Especially in the formation of such large-area plastic washers, it has always been proposed to make these washers circular, and the necessary stiffness could also be achieved with a corresponding curvature or with radial ribs (for example US Pat. No. 4,726,164, US) -A-4 787 188, US-A-4 987 714, US-A-5 069 589, CH-A-666 330). In order to obtain the required large surface area of the washer, these washers, which are essentially circular in shape, of a correspondingly large diameter are required. Especially when fastening sheets in the hem area, that is to say at the respective edge area of the sheets, it is increasingly required that the fastening width claimed is relatively small. Therefore, circular washers with a large diameter can hardly be used, since then a correspondingly large overlap of successive tracks is necessary. Thus, especially when fastening webs, and here in particular roofing webs, the requirement is made to use washers having a rectangular shape, the length of the washer in the direction of the hem being in such a case substantially greater than the slurry ¬ te transverse to the hem direction of such a web. However, this creates strength problems with such large washers, because the pressure surface and the proper distribution of the pressure force must be maintained in spite of this other shape. The present invention has therefore set itself the task of creating a large-area washer of the type mentioned at the beginning, with which a constant contact force or force transmission is made possible practically over the entire peripheral edge, with force application in the direction of all areas of the washer towards the center of the washer, ie towards the fastener used.

According to the invention, it is proposed that the washer have a thickness starting from the central opening and tapering towards the edge, the angle between the respective generatrices of the upper side and the lower side of the washer remaining at least approximately the same in all sectional planes through the central opening .

This inventive design of a washer enables the necessary power transmission and contact force to be made possible even in the case of a rectangular shape thereof. The thickness of the washer is therefore smaller in proportion to the distance from the central opening, so that precisely in the narrower area remaining on both sides of the central opening, the necessary thickness is given to prevent the washer from buckling in this area. It is then also the case that in the case of a washer manufactured according to the invention, the peripheral region of the same is not of equal thickness when closed, but that the side delimitation surfaces of the washer in the central region have the greatest width in relation to their length. Of course, this is most striking in the case of the longitudinal boundary surfaces.

By means of the measures according to the invention, a large-area washer is created which has the required strength and, despite the rectangular shape, ensures the necessary power transmission. Because it is precisely in those areas where there is a risk of kinking that the necessary thickness of the washer is present.

A special embodiment variant of the invention is that the top and / or the bottom of the substantially rectangular washer is or are approximately flat in the shape of a cone or pyramid, the central axis of the cone or the pyramid coinciding with the central axis of the central opening . The generators referred to, which form the taper angle, can therefore be the generatrices of a very flat cone or a very flat pyramid, the opposite top or bottom also being able to be made flat. However, it is also conceivable to combine the flat cones and pyramids with one another, so that, for example, the top in the form of a flat Chen cone and the underside is designed in the form of a flat pyramid. Depending on the required taper angle and on the design and material of the washer, the cones or pyramids forming the top and the bottom can point with their tips in the same or in opposite directions.

Another embodiment variant is that the top and the bottom of the essentially rectangular washer are formed by the same flat cones or pyramids, the tips of which face away from one another. In such an embodiment, the washer is approximately symmetrical with respect to a horizontal central plane, so that there is an approximately roof-shaped elevation towards the top and a mirror-image formation towards the bottom. It just goes towards the center of the washer, i.e. in the area of the fastener used, the underlying track or the underlying insulating material compresses more than towards the edge area of the washer. In addition, such a design has taken into account the requirement for a washer of relatively small thickness. When laying the subsequent sheet and welding the overlap section, it was found that the washer, which is used for the screw connection, should not protrude particularly high above the surface of the sheet, since this increases the overlap area for producing a tight connection in the overlap area must become.

The configuration according to the invention makes it possible to provide material-saving measures without reducing the strength of the washer, it being proposed that niche-like recesses are provided on the upper side, between which web-like ribs remain. These cutouts are also of particular advantage because the formation of voids during manufacture can be ruled out as a result of the lower material accumulations.

An advantageous embodiment of the washer according to the invention provides that the corner areas thereof are rounded. This has the advantage that, with a corresponding load, in particular with a tipping load due to suction forces acting on the tracks, no sharp corner edges of the washer can penetrate the tracks.

In experiments, a very special size ratio of the washers has proven to be useful. The proposed washer is characterized in that the ratio of its length to its width is approximately 1.5: 1 to 1.75: 1, preferably 1.625: 1. With such a dimensional ratio, there is a guarantee that on the one hand, the necessary forces can be transmitted up to the boundary surfaces on the narrow sides, and on the other hand, nevertheless, there is a necessary elasticity of the washer in this more distant boundary region. With such a design, the requirement for a relatively narrow washer for the seam fastening of webs can be met, although a corresponding surface for the force transmission of the large-area washer is still available.

It is advantageous in the washer according to the invention if it is made of a rigid plastic. The production from plastic is particularly advantageous given the proposed thickness ratios of the washer (taper angle). Since such large-area washers can also be referred to as mass articles despite the special field of application, this results in a very simple production possibility and thus also a cost reduction.

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

1 shows a section through a fastening case with a washer according to the invention in the hem region of a web;

Figure 2 shows the same representation of the attachment, but corresponding forces act on the web.

Figure 3 is a side view of the washer seen from the long side.

4 shows a longitudinal section through the washer.

5 is a top view of the washer;

6 is a view of the narrow side of the washer;

7 shows a cross section through the washer.

Fig. 8 is a view of the washer from below. An insulation layer 2 is fastened together with a sheet 3 to a fixed substructure 4 by means of a fastener 6 which interacts with a washer 1. In the example shown here, the fastener 6 is designed as a screw with a threaded section 21 and a drill bit 22. A further threaded section 24 is provided below the screw head 23, which engages in a collar 25 on the washer 1. This practically creates a sure-footed connection between the fastener 6 and the washer 1. The hem region 7 of the web 3 is fastened with the fastener 6 and the washer 1, the washer 1 engaging in the web 3 by means of tips 13 formed on the underside thereof, thereby increasing the friction between the washer 1 and the web 3 increase. This is necessary if, for example, flat roofs are subject to suction loads in the arrow directions 10 due to wind gusts. In such a case, the webs are raised accordingly in the direction of the arrow 10, the edge region 16 of the washer on the right in FIG. 2 being pulled up in the direction of the arrow 11 and the left edge region 15 being pressed down in the direction of the arrow 12.

After the seam region 7 of the web 3 has been fastened, the next following web 3 'is placed with an overlapping region 8, the webs 3, 3' being sealed tightly at the direct edge of the overlapping region 8 by an adhesive layer 9 or by appropriate welding.

The washer according to the invention is explained in more detail with reference to FIGS. 3 to 8. The central opening 5 with the collar 25 projecting downward can be seen. On the underside 30 of the washer 1, tips 13 are provided in a plurality of rows 19 and 20 at a distance from one another, the tips of successive rows 19 and 20 being arranged offset by the dimension V from one another. The tips 13 have a relatively small length L, which corresponds approximately to the thickness or slightly more than the thickness of the web to be fastened. The dimension D at the base of the tips 13, which can be in the form of cones or pyramids, corresponds to approximately half the length L.

The washer 1 essentially has a rectangular shape, that is to say the dimension A is larger than the dimension B. It would also be conceivable to design the washer in the form of a square, but in this case there are in no way the same problems to be solved as in the case of an elongated, rectangular washer. However, the measures according to the invention could certainly be used in a washer, for example, which is similar to an ellipse, since an ellipse-like shape, with the inclusion of the rounded corner regions 33, approximates a rectangular shape. The washer 1 has a thickness starting from the central opening 5 and tapering towards the edge limits 15, 16, 17, 18. A thickness C is thus given in the direction of the opening 5, whereas there is still a thickness E in the region of the edge delimitation 17 or 18. The thickness F is given at the edge regions 15 and 16, specifically in the middle in relation to their length. This tapering thickness is achieved in that the angle W between the respective generatrices 34 and 35 of the upper side 31 and the lower side 30 of the washer 1 remains at least approximately in all sectional planes thought through the central opening 5. Both the upper side 31 and the lower side 30 of the washer are then to be understood as a casing of a rotating body or at least of a structure similar to a rotating body. The upper side 31 and / or the lower side 30 is or are expediently of a flat, conical shape, the tips of the cones which form the upper side 31 and the lower side 30 pointing in opposite directions.

In order to achieve a taper angle W, it would also be conceivable to form a correspondingly flat cone only in the area of the upper side 31 or the lower side 30, in which case the opposite side could then be flat. However, a variant is also possible in which the tips of the flat cones forming the upper side 31 and the lower side 30 point in the same direction. Then there is a kind of roof shape of the washer 1, which roof shape can point both upwards, ie towards the top 31, and downwards, ie towards the bottom 30. Such a possibility can be selected depending on the material to be fastened.

Within the scope of the invention it is of course also possible to adapt the top 31 and / or the bottom 30 to the shape of a flat pyramid instead of such a flat cone. It is true that there are slight deviations with respect to the taper angle W precisely in the area of the transition edges between the pyramid surfaces, but this has hardly any influence in the case of such a flat design of a pyramid or a cone.

5 and the sections according to FIGS. 4 and 7, niche-like recesses 36 are provided on the upper side 31 of the washer 1, with web-like ribs 37 remaining between these recesses 36. Such a configuration does not impair the rigidity and power transmission capability of the washer 1, but it is possible to achieve a substantial saving in material and weight for the washers. The arrangement and the course of the ribs 37 are not of particular importance per se, this can be selected in accordance with the most rational manufacturing process. The recesses 36 and ribs 37 have an advantageous effect especially in a manufacturing process from a rigid plastic, because the reduction in material, ie when large material accumulations can be avoided, can also practically exclude blowholes. It is therefore possible to manufacture high-quality plastic washers. Washers with the features according to the invention are extremely stable in the central area, but can follow the dynamics of the tracks 3 further out, at the distant edge areas.

The rounded corner areas 33 of the washer 1 further contribute to the fact that the web cannot be damaged even with corresponding wind loads.

In the case of a special structural design of the washer 1, the ratio of the length A to the width B thereof is preferably 1.625: 1. In order to enable a correspondingly balanced distribution of force, it seems appropriate if the ratio of length A to width B is in the range between 1.5: 1 to 1.75: 1.

Within the scope of the invention, it would be conceivable to produce one made of cast aluminum, for example, instead of a large plastic washer. However, it would also be possible to use other, non-metallic materials which enable production with a thickness which tapers towards the edge region.

Claims

1. Large-area washer, essentially having a rectangular shape, with a central opening for inserting a fastener for fastening insulation layers and, if appropriate, covering sheets on a solid substructure, characterized in that the washer (1) is one of the central one Opening (5) has an outgoing thickness (C, F, E) tapering towards the edge boundary (15, 16, 17, 18), the angle (W) between the respective generatrices (34, 35) of the upper side (31) and the underside (30) of the washer (1) remains at least approximately the same in all sectional planes through the central opening (5).

2. Washer according to claim 1, characterized in that the top (31) and / or the underside (30) of the substantially rectangular washer (1) is or are approximately flat conical or pyramidal, the central axis of the Ke¬ gel or the pyramid coincides with the central axis of the central opening (5).

3. Washer according to claim 2, characterized in that the top (31) and the bottom (30) of the substantially rectangular washer (1) are formed by the same flat cones or pyramids, the tips of which face away from each other.

4. Washer according to one of claims 1 to 3, characterized in that niche-like recesses (36) are provided on the upper side (31), between which web-like ribs (37) remain.

5. Washer according to claim 1, characterized in that the corner regions (33) are the same rounded.

6. Washer according to claim 1, characterized in that the ratio of length (A) to width (B) of the same is approximately 1.5: 1 to 1.75: 1, preferably 1.625: 1.

7. Washer according to claim 1, characterized in that it is made of a flexible plastic.