EP3098360B1

EP3098360B1 - Non-settling log structure

Info

Publication number: EP3098360B1
Application number: EP16171967.9A
Authority: EP
Inventors: Harri ISOMÄKI
Original assignee: Primapoli Ltd Oy
Current assignee: Primapoli Ltd Oy
Priority date: 2015-05-29
Filing date: 2016-05-30
Publication date: 2018-08-01
Anticipated expiration: 2036-05-30
Also published as: FI126679B; EP3098360A1; FI20155415A

Description

The invention relates to a non-settling log structure, which includes logs set on top of each other, in which there are vertical through holes at a distance from each other, and a structure extending essentially over the whole distance of the log structure in the openings of the through holes aligned with each other, and the logs of a log pair forming a log joint are attached to each other and free of the support structure using mechanical attachments, the attachment point of the attachments is essentially in the area of the centre line of the log.
As is known, a log structure settles during its lifetime, particularly at the start of its service life. In other ways too timber material lives, mainly due to variations in moisture content. In addition, the living of a log structure is increased by temperature and humidity differences between the indoor and outdoor air. Attempts have been made to reduce settling and moisture living by means of construction of the log itself and treatment. The logs, however, then become complicated and difficult to manufacture. In addition, the desired effect has remained small, while the production costs have increased considerably. At the same time, the appearance of the log suffers.
A log wall intended to be non-settling is described in Finnish utility model number 10462 . In the log wall disclosed, the logs are nearly traditional, so that unnecessary work stages are avoided in the manufacturing stage. At the same time, the log's appearance remains as before. Here, in the logs, there are vertical holes in the central area, in which wooden dowels are fitted. Each wooden dowel consists of several dowel parts, which are consecutive and in immediate contact with each other. Thus, the wooden dowels carry the vertical loads of the log wall. In addition, the logs are arranged to be immoveable relative to the wooden dowel. This is implemented by means of a narrowing of the vertical holes and a corresponding thinning of the dowel part.
Due to the narrowing and thinning, two sizes of drill holes must be made in the log. Machining must then be performed twice. The dowel parts are also short and their strength varies. Due to the dowel parts, several pivot points form in the support structure, i.e. the dowels, so that the lateral stability of the log wall is poor. In addition, when machining the logs, there are several additional work stages using many types of tool, and, when assembling the log wall dowel parts must be placed at each log layer. This slows erection and makes installation errors possible.
US2005/126084 discloses a substantially pre-assembled modular log home. The log home is made from stacked structural members that form a front, a rear, and a pair of side-walls that are each secured to a sub-floor. Each structural member has a rectangular elongate body. Fasteners secure the members together in each stack. A roof, having an assembly of rafters, is secured to the top of the log home.
The invention is intended to create a new type of non-settling log structure, which is more stable than before and keeps its shape despite moisture living. The characteristic features of the log structure according to the present invention are stated in the accompanying Claims. In the invention, the logs are supported in a new and surprising way. It is then certain that the log structure is non-settling and the gaps between the logs will remain tight. Large window and door openings, for example, are then possible while the appearance of the log structure remains unchanged. The lateral stiffness of the log structure is also significant. The vertical loading of the log structure is then good and at the same time the log structure will withstand lateral loading. Further, the erection of the log structure is rapid and the log layers are sure to remain in place and in the correct attitude during erection. The finished log structure is non-settling and rigid, but permits the moisture living typical of a log. At the same time, the seals between the logs act for the whole lifetime of the cross structure, without being excessively loaded.
In the following, the invention is described in detail with reference to the accompanying drawings showing some embodiments of the invention, in which

Figure 1a: shows schematically the living of the log structure as the seasons change,
Figure 1b: shows a top view of the log structure according to the invention from two different points,
Figure 1c: shows a side view of the log structure of Figure 1b,
Figure 2: shows an enlargement of the log structure according to the invention,
Figure 3: shows an end view of the log structure according to the invention,
Figure 4a: shows a variation of the log structure of Figure 3, and
Figure 4b: shows the variation of the log structure in the manner of Figure 1b.

Figure 1a shows the applicant's own log profile. Here, the lower log is shown in the form in which it comes from the production line. The individual laminae are not shown here. In practice, the log is formed of several laminae glued to each other, and the final profile and the tongues and grooves are obtained by suitable machining. The whole log is thus of a set dimension and shape over its whole length. In Figure 1a, the inside of the building is on the right-hand side and the outside on the left-hand side. The upper log 12 is shown in the state in which it has dried and shrunk to in early spring, which can be seen at the right-hand edge of the upper log 12. In the profile shown, there is also a drip moulding 10 in the groove in the lower part. The drip moulding makes the gaps arising from the natural drying of the log invisible. The log structure thus retains a neat and high-quality appearance for its whole lifetime. The drip moulding also brings advantages in the outer surface of the log. The drip moulding keeps rainwater out of the insulation space between the logs and keeps the log wall a guaranteed tight and safe structure.
Figure 1b shows a top view of the log structure according to the invention and Figure 1c a side view. At the left-hand side of Figure 1b, the upper part of the log structure can be seen and correspondingly at the right-hand side the lower part of the log structure. The log structure is non-settling and it includes logs 11 and 12 set on top of each other. In logs 11 and 12, there are vertical through holes 13 at a distance from each other (Figure 2). In the finished log structure, the through holes are aligned with each other and in the opening 14 formed by the aligned through holes 13 is a support structure 15 extending essentially over the whole distance of the log structure and carrying the vertical load. Here the whole distance refers to the vertical distance from the lowest to the highest logs of the log structure. The support structure carries the vertical load of the log structure, making the log structure non-settling. According to the invention, the logs 11 and 12 of the log pair 31 forming the log joint 16 are attached to each other by means of mechanical attachments 32 and are separated from support structure 15. Thus, each log remains attached to the others, but the logs float relative to the support structure. At the same time, the support structure and not the logs carries the vertical loads acting on the log structure. The gaps and positions of the logs then remain unchanged. Thus, the seals act as desired and the formation of gaps between the logs is avoided. Here the term log joint refers to a joint between two opposing logs.
The attachments are located in a specific manner. In the invention, the attachment point 17 of the attachments 32 is essentially in the area of the centre line 18 of the logs 11 and 12. The logs are then attached to each other in the centre, so that the edge parts of the log can live despite the attachment.
Preferably the attachment 32 is formed of a fully threaded screw 19, which extends on both sides of the log joint 16. The logs forming the log joint then remain attached to each other and the attachment carries the weight of the log. The formation of the log structure will be described in greater detail later.
The logs 11 and 12 of the log pair 31 are, in addition, attached by partly threaded screws 20 to each edge of the logs 11 and 12 outside the support structure 15. In the invention, the partly threaded screw's 20 threaded part 33 is located in the lower log 11 of the log joint 16. Thus, the partly-threaded screw permits natural movement in the edges of the log, while the log structure is, however, entirely non-settling. At the same time, the partly threaded screw supports the log structure laterally.
Figure 1c shows some of the support structures 15, each of which is formed by a single unified supporter 21. The supporter then carries the whole of the loading of the wall structure, thus achieving a non-settling wall structure. The placing of the support structure is also new and surprising. In the invention, the supporters 21 are situated in rows 22 and 23 (Figure 1b) separate from the area of the two logs 11 and the centre line 18. The support structure then extends over a wide area, improving the lateral stability of the wall structure. At the same time, the through holes made for the support structures remain small, without weakening the log and the wall structure formed of the logs.
The supporter 21 preferably has a support point 24 on top of the lowest log in the wall structure. The first log layer can then be formed in the normal manner. At the same time, the transfer of moisture to the support structure is avoided. In addition, there is a metal shear plate 25 between each end of the supporter 21 and the log. Distribution of the loading to both the log and the supporter is then ensured, without the deformation of the log, support structure, or shear plate. There is a suitable and level machining 34 in the upper surface of the lowest log for the shear plate 25. The machining is a recess, which is at least as deep as the thickness of the shear plate, so that carrying the shear plate is avoided. In other words, the log lies against the log, when the depth of the machining corresponds to the thickness of the shear plate. The machining also holds the shear plate is the correct position when the next log is installed. The machining is shown in only three places in Figure 4b, but the machining is are preferably at each shear plate. In an as such known manner, the log structure is gathered into a bundle by means of a threaded rod 26, for which there are central drill holes 27 in the logs. Threaded rods are placed as required. In any event, the logs also float relative to the threaded rod. The central drill holes are not shown in Figure 1c. Other vertical drill holes can also be made in the log, for example, for electrical wiring.
In the invention, the supporter 21 is preferably a wooden dowel with a circular cross-section. The wooden dowel is non-settling and its load bearing capacity is sufficient. In the direction of the grain, the compressive strength of wood is many times that of the transverse direction and its living is much less. In addition, as a material a wooden dowel is cheap and easy the manufacture, for example, by planing. The through hole too is round and is thus easy to machine in the log. For example, a 40-mm through hole can be used in the log, into which a 35 - 38-mm diameter wooden dowel is fitted. The dowel-hole combination is chosen in such a way that a full length dowel can be installed without damaging the dowel. Using a sufficient tolerance, installation is easy and at the same time the floating of the logs can be ensured. For example, at window openings or points requiring particular support, the through hole can be given, for example, a rectangular shape, in which a glulam pillar can be placed. The wall structure can then be given, if required, support points, which are outwardly invisible. Despite the glulam pillar, the wall structure is non-settling as the logs are floating.
The structure described above is advantageous in a wall structure, in which each log 11 and 12 is a laminated log that is lower than it is wide. However, the structure according to the invention can be implemented with any side ratios whatsoever. The edges of wide logs move a great deal, which the partly threaded screws now permit. On the other hand, in a wide log the support structures will fit well in two rows. Two rows can also be used in narrow logs. So-called staggering is then applied, in which the through holes alternate in the inner and outer surfaces of the log (Figure 4b). Excessive local weakening of the log at the locations of the through holes is then avoided. Generally, the supports 21 of the rows 22 and 23 are arranged in parallel or overlapping. In practice, using the through holes shown, staggering is used if the log is narrower than 240 mm.
Figure 3 shows an end view of the wall structure of Figure 1c without attachments. Figure 4a shows a variation of the log structure according to the invention. Here, in the uppermost log of the wall there are through holes, through which the support structures extend through the next storey to the shear plate. It is then possible to form multistorey log structures in a non-settling form.
Figure 2 shows schematically the construction of the log structure according to the invention and its formation. A first log layer 29 is arranged on top of a foundation 28 in the normal manner. After this, shear plates 25 are set at the locations of the through holes 13. The upper surface of the log is flat, so that the loading is distributed evenly. In the surface of the log, low machining can also be used, the depth and shape of which correspond to the shear plate. It is then easy to place the shear plate in the correct location, which will be sure to remain in place. Next, a second log layer is placed, the through holes of which are aligned with those of the first log layer. The locations of the through holes have already been dimensioned in the design stage, so that after production they naturally align with each other, if the logs are otherwise correctly installed. A tool extending to both sides of the log joint, which aligns the logs and tightens the logs together (not shown), is preferably fitted into one or more through holes. Next, the partly threaded screws 20, which permit the movement of the logs, are screwed from the edges of the logs. Partly-threaded screws are attached over the area of the entire log layer. Once the log layer is in the correct position, the fully-threaded screws 19 are attached to the centre line of the log, preferably on both sides of the centre line. The fully threaded screws keep the opposing logs attached to each other and receive the movements caused by moisture living. The fully threaded screws are nearly headless, so that they sink deeply through the log without a predrilled hole. More specifically, a fully threaded screw is headless, so that it sinks into the log. What is important is that the fully threaded screw extends to both sides of the log joint. The fully threaded screw 19 preferably extends to both sides of the log joint 16 to essentially the same extent in the logs 11 and 12. The fully threaded screws load bearing capacity can then be exploited and thus the most durable log joint possible achieved. In practice, the length of the fully threaded screw 19 is 1.0 - 1.6-times the height of the log 11, 12. There is then a screw at at least half the height of the log.
After the installation of the fully threaded screws, the tool is withdrawn from the through hole, after which the next log layer is set in place and tightened and secured. Usually, the partly threaded screws are also removed. In other words, the fully threaded screws hold the log joint, which was tightened using the partly threaded screws, closed, but permit the logs to float. If necessary, for example, when a log requires pulling, the partly threaded screws too are left in the structure. By pulling, the log is forced into the correct attitude.
The fully threaded screws are installed on slightly differing lines in different log layers, to avoid them striking each other. The alignment is selected in either the transverse direction of the log (Figure 2) or the longitudinal direction of the log (Figure 1c), or in both directions, as long as care is taken that the fully threaded screws do not strike each other. Staggering thus permits the use of long fully threaded screws. At the same time, the moisture living of the logs is evened. In other words, local warping due to the effect of moisture living is avoided, which for its part prevents the formation of gaps. When the log structure reaches its finished height, wooden dowels of the designed length are placed through the holes and a shear plate is again fitted to the upper end of the dowel, on top of which the uppermost log layer is placed (Figures 1c and 3). Roof trusses can then be installed on top of the uppermost log layer, the wall structure being non-settling as the support structures fitted inside the logs carry the vertical load. The logs arranged to float carry only their own weight, without participating in any way in carrying the vertical loads.
The through holes can be made using conventional machine tools without complicated additional work stages. The actual erection of the log structure is rapid and the log layers remain firmly in place. In addition, full length dowels can be used and they can be installed in the very final stage of erection. The log structure described is advantageous, especially when using massive laminar logs, but it can also be applied to other kinds of log structure. Using floating installation and mechanical attachments between the logs, each log carries only its own weight. With the support structure carrying the vertical forces a non-settling log structure is formed with remains tight without thermal insulation and gaps that detract from its outward appearance. In addition, the logs for the non-settling structure according to the invention can be made on the same production line and using the same machining means as a normal settling log. The additional costs due to production changes are then avoided. Mainly the manner of building the log structure, but through that also the non-settling log structure is novel and surprising. In addition to logs, supports, shear plates and machining for them, and fully and partly threaded screws are needed, and are installed as described above.

Claims

Non-settling log structure, which includes logs (11, 12) set on top of each other, in which there are vertical through holes (13) at a distance from each other, and a support structure (15) extending essentially over the whole distance of the log structure in the opening (14) of through holes (13) aligned with each other, and the logs (11, 12) of a log pair (31) forming a log joint (16) are attached to each other and free of the support structure (15) using mechanical attachments (32), the attachment point (17) of the attachments (32) is essentially in the area of the centre line (18) of the log (11, 12), characterized in that the support structure (15) is carrying the vertical load and the attachment (32) consists of a fully threaded screw (19), which extends to both sides of the log joint (16), and the fully threaded screw (19) sunk through the log (12) is headless.
Log structure according to Claim 1, characterized in that the fully threaded screw (19) extends into both logs (11, 12) by essentially the same extent on both sides of the log joint (16).
Log structure according to Claim 1 or 2, characterized in that the length of the fully threaded screw (19) is 1.0 - 1.6-times that of the height of the log (11, 12).
Log structure according to any of Claims 1 - 3, characterized in that the logs (11, 12) of the log pair (31) are attached by partly threaded screws (20) at each edge of the logs (11, 12) from outside the support structure (15).
Log structure according to Claim 4, characterized in that the threaded part (33) of the partly threaded screw (20) is situated in the lower log (11) of the log joint (16).
Log structure according to any of Claims 1 - 5, characterized in that each support structure (15) consists of a single unified support (21).
Log structure according to Claim 6, characterized in that the supports (21) are situated in two rows (22, 23) separate from the area of the centre line (18) of the log (11, 12).
Log structure according to Claim 7, characterized in that the supports (21) of the rows (22, 23) are arranged to be next to each other or staggered.
Log structure according to any of Claims 6 - 8, characterized in that the support (21) has a support point (24) on top of the lowest log of the wall structure.
Log structure according to any of Claims 6 - 9, characterized in that between each end of the support (21) and the log (11, 12) there is a metal shear plate (25).
Log structure according to Claim 10, characterized in that in the log (11, 12) there is a machining (34) corresponding to the shear plate (25), the depth of which corresponds to the thickness of the shear plate (25).
Log structure according to any of Claims 6 - 11, characterized in that the support (21) is a wooden dowel with a circular cross-section.