NO319922B1 - Ceiling bulkheads of two or more adjacent wooden beams that overlap one another in the longitudinal direction, as well as fastening elements for projecting two overlapping end regions of wood beams for use with a roofing bulkhead. - Google Patents

Abstract

In the case of a roof joint (1), two overlapping wooden beams (2, 3) are joined to each other in the longitudinal direction, which adjoin each other by means of fastening elements. The overlapping end areas of the wooden beams (2, 3) are connected by means of screws (5) which are oriented at an acute angle to the abutting surfaces (6, 7) of the wooden beams (2, 3). The screws (5) are screwed into a plane that extends across the surfaces (6, 7).

Description

The invention relates to a roof joint of several adjacent wooden beams which overlap each other in the longitudinal direction, as they are mutually connected at other overlapping end areas by means of fastening elements, as well as a fastening element for connecting two at other overlapping end areas of wooden beams for use in a roof joint.

Roof ridge joints or so-called rafter roof rafter joints are formed by single-span girders which, with the help of the supports, e.g. the rafters, by means of nailing or taping, are flexibly connected to continuous girders. The individual girders formed as wooden beams are arranged fieldwise with the beam width offset in relation to each other and usually overlap in the area for the supports or trusses located below. As a mutually rigid connection is required between the overlapping end areas, ordinary bolts alone are not permitted as a means of connection due to their yielding property. In this context, it has previously been proposed that recesses are arranged on the opposite surfaces of the overlapping end areas of the wooden beams, disc-shaped connecting elements being inserted into these recesses and which are to absorb the shear forces between the two overlapping end areas of the wooden beams. These additional anchors which penetrate the end areas of the wooden beams and the disc-shaped parts hold two overlapping end areas of wooden beams together. When using such fastening elements, a load with shear force influence and bending occurs above all. Accordingly, a correspondingly larger dimensioning of the fastening elements to be used is also needed.

From FR 865.513 A, a wooden connection is known which is arranged at an acute angle to the opposite surfaces of the wooden beams and which is always screwed in at an acute angle to the grain direction in the wooden beams, so that when a load on the wooden connection on the screw results in further pulling out and tear-out forces.

The design according to EP 0 448 915 A describes a method for producing a suspended ceiling as well as a screw for carrying out this method. In order not to strain the insulation layer lying in between, the wooden beams are kept at a certain distance from a wooden support structure located underneath. The screws used therefore essentially act as spacers between two spaced wooden beams.

In the case of a known connection element for plate-shaped parts (DD 236 563 A1), a cylindrical bolt is arranged which, in its two end areas, exhibits two thread sections of different diameters. Such a connecting element must be inserted into a pre-drilled hole and must above all serve to connect structural joints and connections to each other at a junction.

The task underlying the present invention is to produce a roof joint of the first-mentioned type as well as a fastening element for connecting wooden beams to a roof joint, respectively with which a significantly improved mutual retention of the overlapping end areas of wooden beams is made possible.

According to the invention, this task is solved by a roof joint whereby the overlapping end areas of the wooden beams are connected to each other by means of screws which are at least roughly oriented in a plane that runs across the adjacent surfaces of the wooden beams and are screwed in place at a point or right angle in relation to these surfaces.

By means of these features according to the invention, the inserted fastening elements in the form of screws are stressed in a combination of tension and pressure, the forces being taken over by

the thread arranged on the screw. With such a roof joint, no preparatory work is practically necessary, as the screwing in of the screws, which are screwed in oriented at an acute angle to the opposing surfaces of the wooden beams, can take place on site at the construction site. With such a procedure, practically no stress on bending and cutting results, but it results almost exclusively in tension and pressure. This results both in the use of screws as fastening elements, as well as in the special type of screwing in a plane that runs across the surface. A particularly good effect results from the acute-angled screw-in. furthermore, as a rule, a quick and, above all, secure mutual fixation of wooden beams is also possible, as such screws do not have to be pre-drilled.

Further improved design is achieved when screws oriented in pairs with a distance parallel to each other are used or also screws in pairs, which in intersecting directions are oriented in planes that follow each other with a small distance. An optimal connection is thereby achieved between the overlapping end areas of wooden beams, as the tensile and compressive forces are transferred in the same way to both end areas of the wooden beams.

In such a variant, it is proposed that the paired screwed-in screws, possibly crossing and following at a distance from each other, are screwed in from the same externally located surface of a wooden beam. In this case, each screw from one side is screwed in once at a right angle or in an obliquely upward direction and once at a right angle or in an obliquely downward direction, since this is probably the simplest solution from the point of view of handling. The mutual connection of wooden beams to roof joints can thus always be made from the same side.

However, there is also the possibility that one of the parties in question is paired

possibly intersecting and successively inserted screws are screwed in starting from the outer surfaces of the two wooden beams that are to be connected to each other. Depending on the type of load and also depending on the design of the screws to be inserted, such a design variant can be advantageous.

In this context, it is also possible that one or more pairs of possibly crossing inserted screws are inserted at a small distance from the relevant end of a wooden beam. Preferably, such a design variant is used, especially for strongly dimensioned roof joints and long overlapping end areas of the wooden beams. Several fastening sections are then arranged over a larger area of the overlapping end areas.

When using screws as fastening elements, however, far more possibilities can be provided with the help of the present invention. Thus, a special design ensures that one or more of the screws screwed in at an acute angle protrude above the underlying surface of the wooden beams that are to be connected to each other and engage with their respective ends in a wooden girder arranged underneath. In this way and according to the invention, it is therefore not only possible to carry out a mutual fastening of the overlapping end areas of wooden beams in an optimal way, but it is also possible that the roof joint formed by the wooden beams is connected to the arranged wooden beams underneath. Precisely when, for the individual wooden beams in the roof joint, the spans are not too large, it could possibly be sufficient that the two overlapping end areas of the wooden beams are practically connected to each other in a work step and, in addition, the roof joint thus formed is fixed to the wooden beams arranged underneath . Thereby, it is always possible at the immediate ends of the overlapping end areas of the wooden beams to additionally insert screws for the mutual fastening.

When fixing a roof joint with a wooden beam lying underneath, it can also be an advantageous design in that in the area of the crossing between a roof joint and a wooden beam arranged underneath, next to the screws inserted at an acute angle or instead of these, one or more screws are inserted in parallel to the facing surfaces of the two overlapping end areas of the wooden beams. The screw or screws inserted parallel to the surfaces facing each other practically only serve for the mutual fastening of the roof joint with the wooden beam, as it mainly depends on the roof joint not tilting on the wooden beam running with a corresponding roof slope. It is therefore only necessary to adapt the roof ash joint accordingly to the wooden carrier.

In this context, it is advantageous that the additional screw or screws are assigned to the overlapping end area of the overlying wooden beam in the direction of the roof slope. In this way, a further reinforced pre-stalling is achieved in connection with the tilting moment, as there is a fastening in the uppermost section calculated on the roof slope, and the lowermost section of the roof joint forms, seen in the direction of the roof slope, the additional repulsion and thus constitutes a corresponding weight arm. Thereby, with the help of the screw or screws that are inserted, only a relatively small force is needed to prevent tilting of the roof joint.

Optimum mutual fastening of the overlapping end areas

of wooden beams to a roof joint is then achieved when the screws inserted inclined at an acute angle to the surface of the wooden beams include an angle of approximately 45° with the surface, so that the following screws crossing each other at a distance from each other are arranged

at right angles to each other. In this way, a very uniform distribution of the forces is achieved on the two end areas of the wooden beams, as both screws in the relevant pair are then stressed in the same way in terms of tension and pressure.

The fastening element according to the invention for connecting two overlapping end areas of wooden beams for use in a roof joint is characterized by a screw with a stem and which at least at its two end areas exhibits a threaded section, as two sections with different diameters follow each other and which have same thread pitch, and where the section with the larger diameter exhibits a core diameter that at least approximately corresponds to the outer thread diameter of the section with the smaller diameter. By means of these preliminary rules according to the invention, it is achieved that the adjacent, overlapping end areas of wooden beams in this adjacent position are connected to each other, without these, even with corresponding force influence, being pulled towards each other or even pushed apart. An equal thread pitch is thus assumed throughout, so that even with the help of the two thread sections with different diameters already produced thread areas in the wooden beams are not destroyed, but possibly further enlarged in diameter. Precisely in this way, it is also possible to optimally take into account load combined in tension and pressure when used at roof joints.

A particularly advantageous precaution, considered from the point of view of the manufacture of the screw, but also from the use of the screw in wood, lies in matching the diameter of the two thread sections. In this case, no excessively large transformation conditions result in the production of such screws. When screwing such screws into wood, it turns out to be advantageous that with the help of the core cross-section that follows the section with the smaller diameter, the already produced thread is practically flattened, so that only the screw course in the wood but not the total cross-section of the larger-diameter section must be displaced. The thread with the larger diameter again forms a correspondingly larger thread in cross-section and, especially in this area, an even stronger densification of the wood around the screw takes place. Re-cracking at the end areas of the wooden beams is, however, already prevented by first screwing in a threaded section with a smaller diameter. Of course, in this way it is also possible to use such screws without pre-drilling, so that a further work step can be avoided in all cases.

Advantageously, an internal point of attack for a screw-in tool is provided at the free end of the section with a larger diameter. The section can thereby transmit the necessary torque, although there is still the possibility that this section with the inner point of attack can be lowered to below the outer surface of the wooden beam.

With the help of these precautions, an immersion process for the screw head is facilitated. Furthermore, the last couple of screw turns in the wooden beam are flattened, with which further densification of the wood in this area takes place.

Further features and special advantages according to the invention are described in more detail in the following description with the help of drawings in which: Fig. 1 shows a section through a roof joint in the area of an inserted fastening element; Fig. 2 shows an elevation of a screw inserted as a fastening element; Fig. 3 shows one of two overlapping connecting wooden beams forming a roof-ridge joint lying on a wooden girder, the mutual fastening of the wooden beams by means of screws is shown schematically; Fig. 4 shows a similar preparation as in fig. 3, in which, however, the connection between the roof joint and the wooden beam is shown; Fig. 5 shows a section through a roof joint with a connection according to the previously used method; Fig. 6 shows an oblique view of a roof joint with a wooden beam arranged underneath, as both the connection of the wooden beams in the roof joint as well as the connection of the roof joint with the wooden beam in the previously usual manner and manner are depicted; Fig. 7 shows a further design example of a roof joint formed by two wooden beams that overlap to end each other and which abuts a wooden girder, the mutual fastening of the wooden beams by means of screws is schematically shown; Fig. 8 shows a similar illustration as in fig. 7, but in which the previously known connection of the wooden beams by means of nails is shown schematically.

With a roof joint 1, two longitudinally overlapping wooden beams 2 and 3 are mutually connected to each other by means of fastening elements. The roof joints 1 then lie on corresponding supports or on wooden beams 4 which are horizontally oriented or arranged continuously in a corresponding roof slope. In the following description, it is always about two wooden beams 2 and 3 which, connected to each other, form a roof joint. Within the scope of the invention, however, it would be entirely conceivable to arrange more than two overlapping wooden beams connecting each other, as the end areas of wooden beams then e.g. comes alternately from one side and from the other. In such a case, it would also be conceivable that after the mutual fixing of two overlapping end areas of wooden beams, the next wide wooden beam is added and its overlapping end area is fixed again with the following wooden beam. In this case, the immediately adjacent, overlapping end areas of two wooden beams would always be connected to each other.

The mutual connection takes place by means of fastening elements in the form of screws 5, which are oriented at an acute angle to the mutually adjacent surfaces 6,7 of the wooden beams 2,3 and are screwed in as at least approximately extending across these surfaces 6, 7.

As can be seen in particular from figures 1 and 3, in the individual case such screws 5 are inserted in pairs which are oriented in intersecting directions in planes that follow one another at a small distance. Thereby, it is possible that in this case only a pair of such screws 5 are arranged at the two immediate ends of the end areas of the wooden beams 2 and 3. Depending on the forces to be transmitted, however, it may also be advantageous to arrange two such pairs 8 of screws 5 - as shown in fig. 3 - also kneads more than two such pairs 8 of screws 5. By the one in fig. 1 embodiment, each of the pairwise crossing and successively inserted screws is screwed in starting from the outwardly facing surfaces 9 and 10 of the wooden beams 2 and 3

which must be connected to each other. However, it would also be possible that they in it

in some cases, pairs of crossed and spaced inserted screws are screwed in starting from the same externally located surface 9 or 10 of one of the wooden beams 2 and 3 respectively.

The screw-in angle for the screws 5 is chosen according to the particular load times

traps, but a design has proven particularly advantageous in which the acutely angled obliquely in relation to the surface 6,7 of the wooden beams 2,3 inserted screws 5 with the surface 6,7 includes an angle a of approximately 45°. Thereby, the screws 5 that intersect at a distance from each other are oriented approximately at right angles to each other, whereby the tensile and compressive forces on the wooden beams 2, 3 are transferred to the same extent and a load absorption is ensured over the total height of the wooden beams 2,3.

In this context, it should be mentioned that it is not absolutely necessary for the screws 5 to be screwed in starting from the surfaces 9 and 10 of the wooden beams 2, 3. It would also be conceivable for these screws to be attached to the upper side 11 or the lower side 12 of the roof joint, as the then, of course, a relatively far-out area must be chosen in order to be able to engage with both wooden beams 2, 3 by screwing in at an acute angle.

This screw, which can be used as a fastening element, is seen as a possible design variant in fig. 2. In the case of this screw 5, at least or on the two free end areas of a stem, threaded sections 13 and 14 are arranged with different diameters D1 and D2 respectively, but which have the same thread pitch. The section 14 with the larger diameter D2 has a core diameter D3 which at least approximately corresponds to the external thread diameter D1 of the section 13. On the free end of the section 14 with the larger diameter 2, an internal attack point 15 for a screw-in tool is formed. The design of the point of attack for the screw-in tool can of course be done in a variety of ways. In the design shown, a cylindrical screw head 16 with an enlarged diameter D4 is arranged on the end of the stem equipped with the internal point of attack 15 in relation to the threaded section. The transition 17 between the threaded section 14 and the screw head 16 is formed as a blunt cone-shaped extension. Thereby, an immersion option for the screw head 16 is provided in a simple way, without too much expansion of the threaded bore occurring and thereby a crack in the area of the wooden beams 2, 3.

Within the framework of the invention, it is entirely conceivable to use screws 5 with a different configuration. It must only be ensured that the screw 5 on the two end areas of the trunk exhibits a threaded section, so that in both wooden beams 2, 3 which are to be connected to each other there is a corresponding threaded engagement in order to be able to transfer the necessary tensile and compressive forces. Thereby, it is also possible that the two thread sections are matched to each other over their course, i.e. that, despite any existing thread-free stem between the threaded sections, there is a consistently equal thread pitch. However, it is also conceivable to arrange a threaded section over the entire length of the screw 5.

On the free end of the screw 5, a penetration tip 18 is formed, similar to the tip of a wooden rail. Within the framework of the invention, it is also conceivable that a kind of drill bit or a corresponding board is arranged here, in order not only to cause an expansion of the wooden beam for receiving the screw 5 but also to cause a removal of shavings to form a corresponding opening for receiving the screw 5.1 in such a case, the fibers are separated by screwing in the screw 5, thereby possibly reducing the risk of cracking.

From the representation in fig. 4 it can be seen that, in addition to the fastening between the individual wooden beams 2, 3, which form the roof joint, a fastening can also be provided between the roof joint 1 and the underlying wooden beams. At the same time, the screws 5 screwed in at an acute angle protrude beyond the underlying surface 12 of both overlapping end areas of the wooden beams 2, 3 and engage with their ends in the wooden beams 4 arranged underneath. With this type of fastening, a regulatory fastening between the roof joint can also be provided at the same time 1 and the wooden beam 4.1 in this connection, it is also possible that in the area of the crossing between the roof joint 1 and a wooden beam 4 instead of or in addition to the angled inserted screws 5 several screws oriented parallel to the facing surfaces 6,7 are inserted. Such additional screws are advantageously assigned to the overlapping end area of the overlying wooden beam 2 in the direction of the roof pitch. This prevents a tilting of the roof joint to a sufficient extent.

In fig. 5 and 6 show how a fastening of the overlapping end areas of wooden beams to form roof joints and a fastening of the roof joint with wooden beams lying underneath took place with relatively extensive work. In order to connect the two wooden beams 2 and 3, recesses 19 had to be made on the two mutually facing surfaces 6 and 7 in order to be able to insert a disc-shaped part 20 which then absorbed the necessary shear and bending stresses. By further anchoring 21 which penetrates the wooden beams 2 and 3, the mutual connection of the two wooden beams 2 and 3 was effected. For fixing the roof joint 1 with the underlying wooden beam 4, as a rule, corner angles 22 made of sheet metal parts were used and were fixed with screws both on the roof joint 1 and also on the wooden beam 4.

In the design example according to fig. 7 and 8, paired screws 5 are inserted which lie parallel to each other at a small distance. Thereby, it is possible that only one pair of such screws 5 is arranged on the two immediate ends of the end areas of the wooden beams 2 and 3. Depending on the forces to be transmitted, however, it may also be advantageous to arrange two or more such pairs of screws 5. The screws 5 inserted next to each other at a distance can be screwed in from the externally facing surfaces 9 and 10 of the two wooden beams 2, 3 which are to be connected to each other. As can be seen from fig. 1, however, it is also possible for the paired screws inserted parallel to each other to be screwed in starting from the same externally located surface 9 and 10 on one of the wooden beams 2 and 3 respectively.

In fig. 8 shows how fixing the overlapping end areas of wooden beams to form roof joints took place with relatively extensive work. In order to connect the two wooden beams 2 and 3, a large number of nails 23 had to be driven into the two facing surfaces 6 and 7, which, however, could only absorb shear and bending loads.

In and of itself, nails with a smooth stem should be used for roof joints. However, since due to the slope of the roof there are constantly acting stresses on extraction, when using nails with a smooth shank, pre-drilling should not be carried out. For high loads, special nails (screw nails, grooved nails) are used which can be driven in with compressed air driven nailers up to a diameter of 5 mm and up to a maximum length of 160 mm. Nails with a larger diameter or longer length must be driven in by hand, as pre-drilling should not be done here either. These works are time-consuming and possibly also dangerous, as they usually have to be carried out at a great height on a construction site.

This makes it clear that the described precautions achieve a significant improvement in the mutual connection of wooden beams to roof joints and also between roof joints and wooden beams. Not only the connection itself but also the handling and especially the handling on the building site is improved, as no precisely fitting recesses have to be made in the wooden beams in advance and no holes have to be drilled in advance.

Claims (9)

1. Roof joint comprising a plurality of wooden joists abutting one another longitudinally at their overlapping end regions and rigidly connected by means of screws, wherein the screws are located in a plane extending at least approximately transversely to the adjacent surfaces of the wooden beams, i.e. at least approximately at right angles to the longitudinal axes of the wooden beams, characterized in that the screws (5) are aligned in the planes which run approximately at right angles to the longitudinal axes of the wooden beams (2, 3) at an acute angle to the adjacent surfaces (6, 7) to the wooden beams {2, 3), and that the screws (5) are screwed into the wooden beams (2, 3) without pre-drilled holes. 2. Roof joint according to claim 1, characterized in that respective pairs of screws (5) are used, which are arranged horizontally in intersecting directions in successive planes with a small distance from each other. 3. Roof joint according to claim 2, characterized in that the screws (5) which respectively cross each other in pairs and are inserted successively at a distance from each other, are screwed in from the same external surface (9,10) to a wooden beam (2, 3) 4. Roof joint according to claim 2, characterized in that each of the screws (5), which respectively cross each other in pairs and are inserted consecutively at a distance from each other, are screwed in from the mutually remote external surfaces (9,10) to the two wooden beams (2, 3) which are to be connected together. 5. Roof joint according to one of claims 2 to 4, characterized in that in each case one or more pairs (8) of screws (5) are inserted and which cross each other, introduced at a small distance from each other from the respective end of a wooden beam (2, 3). 6. Roof joint according to one of claims 2 to 5, characterized in that the screws (5) which are inserted at a sharp angled slope to the surface (6, 7) of the wooden beams (2, 3) form an angle (a) of about 45°C with the surface, so that the crossing screws (5 ) which succeed each other at a distance from each other are placed at right angles to each other. 7. Roof joint according to any one of claims 1 to 6, characterized by one or more of the screws (5) which are screwed in at an acute angle projecting over the bottom surface (12) of the wooden beams (2, 3) which are to be joined together and connected at their end or ends to a wooden supporting beam placed underneath. " 8. Roof joint according to claim 7, characterized in that, in the vicinity of the intersection between a roof joint (1) and a wooden support beam (4) placed underneath, in addition to the screws (5) inserted at an acute angle, one or more additional screws are inserted parallel to the adjacent surfaces (6, 7) to the two mutually overlapping end areas of the wooden beams (2, 3) 9. Roof joint according to claim 8, characterized in that the additional screw(s) is connected to the - overlapping end area of the wooden beam (2, 3) located at the top in the direction of the roof slope.