LAMINATED LOG

Abstract

 The laminated log has a first surface lamella (10), a second surface lamella (12) and at least one vertical lamella (14) between the first surface lamella (10) and the second surface lamella (12), the direction of wood grains in the vertical lamella being substantially perpendicular to the longitudinal direction of the laminated log. The laminated log has a lower surface (18), in which there is a first sealing groove (20) for receiving a seam seal (21). The first sealing groove is at the boundary surface of the first surface lamella and the vertical lamella. The lower surface preferably also has a second sealing groove for receiving a seam seal, the second sealing groove being located at the boundary surface of the second surface lamella and the vertical lamella. The sealing grooves can be for their main part or substantially entirely in the vertical lamella.

Description

[0001] The invention relates to a laminated log, which has a first surface lamella, a second surface lamella, and at least one vertical lamella between the first surface lamella and the second surface lamella, the direction of the wood grains in the vertical lamella being substantially perpendicular to the longitudinal direction of the laminated log, and a lower surface, in which there is a first sealing groove for receiving a seam seal.

[0002] Massive log has long been used as a material in house construction. Log construction is a traditional method of construction with several special characteristics. The construction method makes possible, for example, the fast erection of the building frame and, when needed, fast dismantling and reassembly. Log functions as the bearing frame of the building and, at the same time, as heat and sound insulation. Massive log has the ability to store heat and moisture and release these back to room air. Because of the special characteristics of log buildings, massive log is a desired and valued construction material.

[0003] A problem with log buildings is the shrinkage caused by the drying of logs, which causes the log walls to settle. The settling of walls causes problems, among others, in the realization of joints between the unsettling sections of the building frame and the settling walls. The contraction of logs in the transverse direction can be significantly reduced by arranging one or several vertical lamellas between the surface lamellas of the laminated log, the wood grains of the vertical lamella being perpendicular to the longitudinal direction of the log. Such laminated logs have been described, for example, in the specifications EP 0380057, EP 0226567 and DE 29923387 U1. A problem with logs equipped with vertical lamellas is the realization of the sealing of the seam between the logs. When they dry, vertical lamellas shrink clearly less than surface lamellas, in which the grain direction is the same as the longitudinal direction of the laminated log. Because of this, the seam between the surface lamellas in superimposed laminated logs broadens as the log dries so that the seals arranged between the surface lamellas are not able to efficiently seal the seam.

[0004] It is an object of the invention to introduce a laminated log, with which drawbacks and disadvantages relating to the prior art can be reduced.

[0005] The objects of the invention are achieved with a laminated log, which is characterized in what is presented in the independent patent claim. Some advantageous embodiments are shown in the dependent patent claims.

[0006] The object of the invention is a laminated log, which has a first surface lamella, a second surface lamella, and at least one vertical lamella between the first surface lamella and the second surface lamella, the direction of wood grains of the vertical lamella being substantially perpendicular to the longitudinal direction of the laminated log. The laminated log has a lower surface, in which there is a first sealing groove for receiving a seam seal. The first sealing groove is in the boundary surface of the first surface lamella and the vertical lamella. Preferably the lower surface also has a second sealing groove for receiving a seam seal, the second sealing groove being located in the boundary surface of the second surface lamella and a vertical lamella. The sealing grooves can be located for their major part or substantially entirely in the vertical lamella.

[0007] Drying shrinkage occurs considerably less in the vertical lamella than in the surface lamellas, in which the grain direction is parallel to the longitudinal direction of the log. Because of this, the sealing groove formed partly in the vertical lamella retains its original form relatively well as the laminated log dries, and the seam seal arranged in the sealing groove can close the seam between the logs.

[0008] In an advantageous embodiment of the laminated log of the invention the lower surface has at least two slits with a bottom surface. The first sealing groove is formed to the bottom surface of the first slit and the second sealing groove is formed to the bottom surface of the second slit as a groove extending from the plane of the bottom surface towards the inner part of the log. Laminated logs typically have an upper surface, which has ribs with a ridge surface. The width of the ridge surface is substantially equal to the width of the bottom surface of the slit. In a log wall, the ribs of the lower laminated log are set in the slits of the upper laminated log so that the ridge surface of the ribs is set against the bottom surface of the slits. Preferably, the width of the bottom surface is substantially bigger than the width of the first or second sealing groove. The width of the bottom surface of the slits refers to the width of the bottom surface before the forming of the sealing groove; in other words, the smallest distance between the slit flanks. The sealing groove removes part of the bottom surface, but a strip of the bottom surface remains in the edge of the sealing groove, setting against the ridge surface of the rib. In the laminated log of the invention, the seam seal in the sealing groove is not entirely flattened even though the ridge surface of the ribs were to press against the bottom surface of the slit. Thus, the seam seal retains its deformation characteristics.

[0009] In a second advantageous embodiment of the laminated log of the invention the cross-sectional form of the first and/or second sealing groove comprises a part of the arc of a circle. The cross-sectional form of the sealing groove can thus be, for example, a semi-circle or a downwards opening U form.

[0010] In a third advantageous embodiment of the laminated log of the invention there is a seam seal in at least one sealing groove, made of elastic, compressible material, such as polyethylene. The seam seal has preferably a circular cross-section and before contraction the diameter of the seam seal is bigger than the largest width of the sealing groove. The seam seal with circular cross-section fills well the sealing groove, the cross-sectional form of which comprises a part of the arc of a circle. The compressible seal can be fitted into a groove, which is slightly smaller than the cross-sectional measures of the seal so that it stays in place in the sealing groove, due to the compression force and friction affecting on the contact surfaces.

[0011] In yet another advantageous embodiment of the laminated log of the invention there are at least two vertical lamellas with an intermediary lamella between them. In the intermediary lamella, the direction of the wood grains is substantially the same as the longitudinal direction of the laminated log. The thickness of the laminated log can be grown by the intermediary lamella by simultaneously keeping the widths of individual lamellas reasonable. By arranging the grain direction of the intermediary lamellas to be the same as the longitudinal direction of the laminated log, sufficient flexural endurance is achieved for the laminated log.

[0012] In yet another advantageous embodiment of the laminated log of the invention the width of the surface lamella is unequal to the width of the vertical lamella. Preferably, the width of the intermediary lamella is also unequal to the width of the vertical lamella and/or surface lamella. The width of the lamella refers here to the measure of the laminated log in the lateral direction, i.e. perpendicular to the side surface of the lamellas. By varying the width of the lamellas of the laminated log, the transverse compression resistance and flexural resistance of the laminated log can be optimized, nevertheless, without increasing too much the total width of the laminated log.

[0013] In yet another advantageous embodiment of the laminated log of the invention the surface lamellas and vertical lamella/vertical lamellas are massive wood or they are constructed of wooden material parts joined together.

[0014] It is an advantage of the laminated log of the invention that the groove formed to the seam seal retains well its shape and that the seam between superimposed laminated logs does not broaden by the sealing groove as the log dries. Thus the seam seal to be installed into the sealing groove retains its sealing ability, even though considerable drying were to occur in the surface lamellas.

[0015] The invention is next explained in detail, referring to the attached drawings, in which

Figure 1a illustrates in an exemplary manner a laminated log of the invention as a cross-sectional view, and

Figure 1b illustrates in an exemplary manner an advantageous embodiment of a laminated log of the invention as a cross-sectional view.

[0016] In Figure 1a there is illustrated in an exemplary manner a cross-sectional view of a laminated log of the invention. A laminated log is a generally known longitudinal structural part, in the cross-section of which there can be distinguished a first side surface 30, a second side surface 32, an upper surface 28 and a lower surface 18. The first and second surface are on opposite sides of the cross-section; likewise, the upper surface and lower surface are on opposite sides of the cross-section. In a complete wall structure the side surfaces form the surfaces of the wall remaining visible. In the lower surface of the log there are two slits 24 extending in the longitudinal direction of the log, and in the upper surface of the log there are two ribs 34, the shape and size of which are compatible with the slits. When laminated logs are piled on top of each other, the ribs of the lower log are set in the slits of the upper log. A double tongue-and-slit joint is thus formed into the seam between the superimposed laminated logs. On the area between the slits and ribs, the upper and lower surface are substantially flat.

[0017] The laminated log illustrated in Figure 1a is formed of three lamellas glued together. The first surface lamella 10 forms the first edge part of the laminated log, and the second surface lamella 12 forms the second edge part of the laminated log. Between the first and second lamella there is a vertical lamella 14. The material of the surface lamellas and the vertical lamella is massive wood. In the surface lamellas, the direction of the wood grains is substantially parallel to the longitudinal direction of the laminated log. In the vertical lamella, the direction of the wood grains is substantially perpendicular to the plane of the upper surface and lower surface of the laminated log and also perpendicular to the longitudinal direction of the laminated log. The vertical lamella consists of a number of short planks placed adjacent to each other and glued from their edge surfaces to the surface lamellas, i.e. there is a glue joint between the first surface lamella and the vertical lamella and between the second surface lamella and the vertical lamella. The parallel planks of the vertical lamella are attached to each other from their boundary surfaces. There can be a glue joint between the contacting boundary surfaces. The height of the lamellas is equal to the height of the entire log cross-section, i.e. they extend from the lower surface 18 of the log to the upper surface 28 of the log.

[0018] By the boundary surface of the first surface lamella 10 and the vertical lamella 14 of the laminated log of the invention there is a slit 24, which has a bottom surface 26. This bottom surface has a first sealing groove 20 parallel to the slit so that the major part of the sealing groove is located in the vertical lamella 14. A small part of the sealing groove extents over the boundary surface of the lamellas up to the first surface lamella. Respectively, by the boundary surface of the second surface lamella 12 and the vertical lamella there is a slit with the second sealing groove 22 in the bottom surface. In Figure 1a, the cross-section of the sealing grooves is the shape of a part of an arc of a circle so that when moving from the open edge of the sealing groove towards the bottom of the sealing groove, the width of the sealing groove first grows, after which it starts to reduce. The biggest width of the cross-section of the sealing groove is thus slightly bigger than the width of the open edge of the sealing groove. The sealing groove can also have an equally wide mouth part and a curved bottom part. A seam seal 21 with a round cross-section is placed into the sealing groove. The seam seal is a band-type part made of elastic, closed-cell material, preferably polyethylene. The seam seal can be closed, or in its middle there can be one or several cavities extending in the longitudinal direction of the seam seal. The diameter of the seam seal is slightly bigger than the biggest diameter of the sealing groove. Preferably, the diameter of the seam seal is 14 mm. The seam seals are attached to the laminated log simply by pressing them in place into the sealing grooves. During the installation, the flexible seam seal compresses slightly so that it fits to travel through the open edge of the sealing groove into the sealing groove. After reaching the inside of the sealing groove, the seam seal tends to resume its original size, i.e. it expands filling substantially the entire sealing groove. Part of the seam seal extends through the open edge outside the sealing groove over the plane of the bottom surface 26 of the slit into the slit 24. The surface of this part of the seam seal extending outside the sealing groove sets against the ridge surface 36 of the rib 34 in the outer surface of the laminated log lower in the complete log wall.

[0019] In the lower surface of the log in Figure 1a there are two slits 24, the first one of which is located by the boundary surface of the first surface lamella 10 and the vertical lamella 14, and the second one is located by the boundary surface of the second surface lamella 12 and the vertical lamella. In a log wall, the laminated logs are piled layer upon layer on top of each other so that the lower surface of the log upper in the wall is set against the upper surface of the log below it so that the ribs of the lower log are settled into the slits of the upper log. The sealing grooves in the bottom surfaces of the slits and the seam seals in them are then set at a distance from each other so that the first sealing groove 20 and the seam seal 21 are at the first edge of the vertical lamella 14 and the second sealing groove and the seam seal are at the second edge of the vertical lamella. In the vertical loading of the wall, the compression resistance of the vertical lamellas is bigger and the deformation ability is smaller than in the surface lamellas so that in the complete log wall, the vertical lamellas of the superimposed laminated logs are pressed tightly against each other. The seam seals in the first and second sealing groove seal the seam surface between the vertical lamellas from their both edges. As the ribs press against the bottom surface 26 of the slits, the seam seals 21 contract slightly in the sealing grooves 20, 22. The elastic seam seal tends to resume its original size so that the surface of the seam seal sets tightly against the ridge surface 36 of the rib. The width of the sealing groove is substantially smaller than the width of the bottom surface 26 of the slit and the ridge surface 36 of the rib. This ensures that the rib does not have room to press inside the sealing groove, but the ridge surface of the rib sets against the bottom surface of the slit. The seam seal in the sealing groove can thus not flatten too much, but it retains always its elastic deformation ability.

[0020] In Figure 1b there is illustrated in an exemplary manner a cross-sectional view of an advantageous embodiment of the laminated log of the invention. In this embodiment, the laminated log has a first surface lamella 10, a second surface lamella 12 and two vertical lamellas 14 between the surface lamellas, with an intermediary lamella 16 between them. The material of all lamellas is massive wood. In the surface lamellas 10, 12 and the intermediary lamella 16, the direction of the wood grains is substantially the same as the longitudinal direction of the laminated log. In the vertical lamellas 14, the direction of the wood grains is substantially perpendicular to the plane of the upper surface and lower surface of the laminated log and perpendicular to the longitudinal direction of the laminated log. In this embodiment, the first sealing groove 20 is formed at the boundary surface between the first surface lamella 10 and the adjacent first vertical lamella 14, mainly to the first vertical lamella 14; and the second sealing groove 22 is formed at the boundary surface of the second surface lamella 12 and the adjacent second vertical lamella, mainly to the second vertical lamella. Seam seals 21 are installed into the sealing grooves.

[0021] The laminated log of the invention is manufactured of a laminated log according to the prior art, in which it is possible to distinguish the first and second surface lamella with at least one vertical lamella between them. At least one sealing groove is formed to the lower surface of such a log, at the boundary surface of the vertical lamella and surface lamella by using a suitable wood-working method, such as planning or milling. The seam seal can be installed in place into the sealing groove in any suitable process step following the forming of the sealing groove. It is easiest to install the seam seal in place at the log house factory so that it is no longer necessary to worry about the installation of the seam seal at the erection site of the log building. The seam seal installed in place into the laminated log is protected at the bottom of the slit of the lower surface so that no mechanical stresses are applied to the seam seal during the transportation of the logs, which might harm the seam seal or detach it from the sealing groove. When needed, keeping the seam seal in place in the sealing groove can be ensured by dispensing glue into the sealing groove before installing the seam seal in place so that a glue joint is produced between the seam seal and the surface of the sealing groove. It is not necessary to install the seam seal in place at the log house factory, but the installation can be made also outside the factory area, such as at the erection site of the log building.

[0022] Some advantageous embodiments of a laminated log of the invention have been described above. The invention is not limited to the described solutions, but the inventional idea can be applied in numerous ways within the limits set by the patent claims.

Claims

1. Laminated log, which has a first surface lamella (10), a second surface lamella (12) and at least one vertical lamella (14) between the first surface lamella (10) and the second surface lamella (12), in which vertical lamella (14) the direction of the wood grains is substantially perpendicular to the longitudinal direction of the laminated log, and a lower surface (18), in which lower surface there is a first sealing groove (20) for receiving a seam seal (21), characterized in that said first sealing groove (20) is at the boundary surface of the first surface lamella (10) and the vertical lamella (14).

2. Laminated log according to claim 1, characterized in that in the lower surface there is further a second sealing groove (22) for receiving a seam seal (21), the second sealing groove (22) being at least for its major part in the vertical lamella (14), at the boundary surface of the surface lamella (12) and the vertical lamella (14).

3. Laminated log according to claim 1 or 2, characterized in that in the lower surface (18) of the log there are at least two slits (24), which have a bottom surface (26), and the first sealing groove (20) is formed to the bottom surface (26) of the first slit (24) and the second sealing groove (22) is formed to the bottom surface (26) of the second slit (24) as a groove extending from the plane of the bottom surface (26) towards the inner part of the log.

4. Laminated log according to claim 3, characterized in that the width of the bottom surface (26) is substantially bigger than the width of the first or second sealing groove (20, 22).

5. Laminated log according to any of the claims 1 - 4, characterized in that the cross-sectional form of the first and/or second sealing grooved (20, 22) comprises a part of an arc of a circle.

6. Laminated log according to any of the claims 1 - 5, characterized in that the major part of the sealing groove (20, 22) is in the vertical lamella (14).

7. Laminated log according to any of the claims 1 - 6, characterized in that at least one sealing groove (20, 22) has a seam seal (21), which is made of an elastic, compressible material, such as polyethylene.

8. Laminated log according to claim 7, characterized in that the seam seal (21) has a circular cross-section and that the diameter of the seam seal (21) before contraction is bigger than the biggest width of the sealing groove (20, 22).

9. Laminated log according to any of the claims 1 - 8, characterized in that the laminated log has at least two vertical lamellas (14), with an intermediary lamella (16) between them, the direction of wood grains in the intermediary lamella (18) being substantially the same as the longitudinal direction of the laminated log.

10. Laminated log according to any of the claims 1 - 9, characterized in that the width of the surface lamella (10, 12) is unequal to the width of the vertical lamella (14).

11. Laminated log according to claim 9 or 10, characterized in that the width of the intermediate lamella (16) is unequal to the width of the vertical lamella (14) and/or surface lamella (10, 12).

12. Laminated log according to any of the claims 1 - 11, characterized in that the surface lamellas (10, 12) and the vertical lamella/vertical lamellas (14) are massive wood or they are constructed of wooden material parts joined together.

Drawing