Method of assembling timber walls for a timber house and a clamping element

Abstract: A base timber (1a) is secured to a base (4) with a screw (5) and successive timbers (1) are stacked thereon and secured with clamping bolts (2). Said clamping bolt (2) is equipped with an internally screw-threaded nut portion (25), a washer (23) and a shank (20) having a screw-threaded region (21). This method of assembling timber walls for a timber house eliminates the accumulated shrinkage of the timber wall during drying. Thus, by the method of the present invention, it is not necessary to reserve a large slide adjusting device or a large settling space, both of which are unavoidable using methods disclosed in the prior art.

Description: In the prior art, timbers (lengths of wood) which have been stacked one on top of another to form a wall of a timber house are secured together at each of a number of locations by a single long bolt running through all the timbers, while a wood dowel is inserted into each timber wall. A base timber is firmly secured to a foundation base by screws. Timber to be used for a timber house has an inferior dryness in comparison with general architectural lumber. Although the degree of dryness is dependent upon the climate or season of building sites, the timber tends to incur some shrinkage in dry periods, and thus the height of the timber wall becomes unavoidably lower after accumulation of the shrinkage imposed on each timber. For example, timber used for timber houses generally has a water content of between 19% and 30%, resulting in shrinkage of the timber by between 1.5% and 4% in due course. Accordingly, in the case where 15 timbers, each 178mm in depth, are stacked to produce a timber wall, this wall is predicted to decrease its total height by between 40mm and 107mm after the drying process. On the other hand, even if laminated wood material, which has a lower water content and therefore low shrinkage ratio is used, it is still unavoidable to incur less than 0.2% shrinkage. Thus, in the example above, the shrinkage of the wall would still be 5.3mm. This unavoidable shrinkage of timbers has caused various problems for timber-house building. For instance, partition walls, stairs and room fittings, all of which incur almost no shrinkage, are to be provided in the timber house. Therefore, when such interior structures are installed within the timber walls, an allowance has to be made for the eventual discrepancy in height of the timber wall after shrinkage occurs. Therefore, a slide adjusting device of a large size is used so that the difference may be absorbed properly. At the same time, in order to absorb the expected maximum shrinkage, a considerable gap, known as "a settling space", must be reserved between the installed interior structures in the ground floor and the first floor. It is quite troublesome work for timber-house builders to use such a large sized slide adjusting device and to provide a large settling space, and therefore a better solution is needed. The object of the present invention is to provide a means wherein the use of a large slide adjusting device and the provision of a large settling space are both avoided, by eliminating the defect where the height of the timber wall is decreased by the drying process of the timber material. According to one aspect of the present invention, there is provided a method of assembling a timber wall for a timber house comprising at a fixing location, the steps of:- a) securing a base-timber to a base by means of a fixing screw having a screw-threaded shank, the shank having a tapered, screw-threaded region, extending through a hole in the base timber and engaging in the base, said fixing screw having a head including an internally threaded nut portion, and a washer which is disposed between the nut portion and the shank and which presses down against the underlying base timber, b) locating another timber on the base timber, c) securing said another timber to the base timber using a clamping bolt having a screw-threaded shank passing through a hole in said another timber and engaging the nut portion of the fixing screw, said clamping bolt having a head including an internally screw-threaded nut portion, and a washer which is disposed between the nut portion and the shank and which presses down against said another timber beneath it, and d) locating and securing each of further successive timbers on the underlying timbers using further clamping bolts in an analogous manner to steps (b) and (c) until the resultant wall is of the required height. Preferably the shank, nut portion and washer of the fixing screw and/or clamping bolt are of unitary construction. At least one sealing strip may be provided between adjacent timbers and alternatively or in addition, a caulking compound may be provided therebetween, so that when the bolt is tightened to clamp the timbers, a seal is provided between said adjacent timbers. When a gap exists between the shank contained in the hole and the wall of the hole, said gap may permit buckling of the bolt in cases where there is considerable shrinkage of the timbers or an unexpected external shock, and the timber house may be badly affected because the weight of the timber wall is supported only by the clamping bolts. In order to avoid this buckling, it is preferable to provide some buckling-prevention means. The buckling-prevention means may comprise an enlarged diameter region of the shank of the clamping bolt and/or fixing screw. Alternatively, said buckling prevention means may comprise a filler in the hole to eliminate the gap. The filler may be sand or a cylindrical pad or any other material of sufficient strength. As a further alternative, the buckling-prevention means may comprise a plate extending around the shank of the clamping bolt and/or fixing screw. Further, the washer may be equipped with a claw or spike which pierces the underside of the overlying timber so as to secure it in position and prevent rotation of the clamping bolt or fixing screw with which it is associated, when the bolt in the overlying timber is rotated. DE-A-4011066 discloses a clamping element for assembling a timber wall comprising a shank having a screw-threaded region, a head having an internally screw-threaded nut portion itself having an internally threaded recess for receiving a screw-threaded shank of another clamping element, and a washer between the head and shank, the shank having hooks to restrain rotation of the clamping element. According to a second aspect of the present invention, there is provided a clamping element for use in the method according to the last preceding paragraph but one, comprising a shank having a screw-threaded region, a head having an internally threaded nut portion, said nut portion having an internally threaded recess for receiving a screw-threaded shank of another clamping element, and a washer disposed between said shank and said head, wherein the washer has a claw or spike projecting in a direction away from the shank. Preferably said shank, head and washer are of unitary construction. In one embodiment of said second aspect of the present invention, the clamping element is a fixing screw, wherein the shank has a tapered screw-threaded region. In a second embodiment of said second aspect of the present invention, the clamping element is a clamping bolt, wherein the shank has a screw-threaded region engageable with the internally threaded recess of another clamping element. According to a third aspect of the present invention, there is provided a kit of parts adapted to be used in a method as claimed in any one of claims 1 to 11, comprising:- a plurality of timbers; a plurality of fixing screws each having a shank with a tapered screw-threaded region, a head including an internally threaded nut portion, and a washer which is disposed between said head and said shank and; a plurality of clamping bolts each having a shank with a screw-threaded region, a head including an internally screw-threaded nut portion, and a washer which is disposed between said head and said shank. Embodiments of the present invention will now be described by way of example, with reference to the accompanying drawings wherein:- Fig 1 is a perspective view to show the securing of timbers by a fixing screw and clamping bolts at a typical fixing location, in accordance with the present invention. Fig 2 is a cross-sectional view of a detail shown in Fig 1. Fig 3 is a perspective view of the clamping bolt. Fig 4 is a side view of the bolt of Fig 3, with part shown in section. Fig 5 is a schematic view to show the stacked timbers forming a timber wall. Fig 6 is a perspective view of sealing strip attachment to a timber. Fig 7 is a perspective view showing the securing of a base timber to a base using a fixing screw. Fig 8 is a perspective view of the screw of Fig 7. Fig 9 is a part sectional view of the screw of Figs 7 and 8. Fig 10 is a perspective view to show a means in the form of a clamping bolt enlargement, to prevent the clamping bolt from being buckled. Fig 11 is a sectional view to show another means in the form of a plate, to prevent the bolts from being buckled. Fig 12 is a sectional view to show a further means in the form of a cylindrical pad to prevent the bolts from being buckled. Fig 13 is a sectional view to show a further means in the form of a filler of sand to prevent bolts from being buckled. Referring now to Fig 5, a timber wall 3 is completed by the firm securing of a stack of timbers 1 using a mutiplicity of clamping bolts 2. The timbers 1 shown in the drawings are of laminated wood, but a raw log timber may be used. Referring to Fig 3 and Fig 4, the clamping bolt 2 has a shank 20 with a screw-threaded region 21, and a head defined by a nut portion 22 having an internally screw-threaded recess 25, and a washer portion 23 disposed between the shank 20 and the nut portion 22. These three parts, the shank 20, the nut portion 22 and the washer portion 23 are of unitary construction. The internally screw-threaded recess 25 is such so as to be able to receive the screw-threaded region 21 of an identical clamping bolt therein, and thus clamping bolts 2 can be joined one to another by screw-engaging the shank 20 of one with the nut portion 22 of another. A spike 24 extends from the washer portion 23 in a direction away from the shank 20, so that in use, it pierces the underside of the overlying timber 1, whereby rotation of clamping bolt 2 is prevented when the screw-engaged bolt in the overlying timber is rotated. In this embodiment, the shank 20 and the nut portion 22 are integrally formed but it is also possible to produce these two parts separately and then join them together by welding or other suitable method. The clamping bolt 2 to be used in the final top timber does not need an internally threaded recess 25 at all, since further loading is not necessary. Referring now to Fig 1, Fig 2 and Fig 6, on the top surface of the timber 1, two tongues 10 in the form of long and slender protuberances are formed longitudinally in parallel, a gap therebetween, while on the bottom surface two corresponding grooves 11 are disposed so as to receive the tongues 10. At each fixing location, a hole 12 is provided perpendicularly through the timber 1 between the two tongues 10. The shank 20 of the clamping bolt 2 can be inserted into the hole 12, which has a slightly smaller diameter than the washer 23 but which is of sufficient size to accommodate the nut portion 22. The holes 12 are located at suitable intervals along the length of timbers 1. Thus, when the timbers 1 are secured, the washer 23 presses downward to clamp the underlying timber tightly while it receives the overlying timber correctly. There may be any number of tongues 10 which may be of any suitable shape. Refering now to Fig 7, the base timber 1a to be located on the base 4, is secured by a fixing screw 5 at each fixing location. As shown in Fig 8 and Fig 9, the fixing screw 5 is similar to the clamping bolt 2, having a shank 50 with a tapering screw-threaded region 51, and a head defined by a nut portion 52 having an internally screw-threaded recess 55, and a washer portion 53 disposed between the shank 50 and the nut portion 52. These three parts, the shank 50, the nut portion 52 and the washer portion 53 are of unitary construction. The internally screw-threaded recess 55 is such so as to be able to receive the screw-threaded region 21 of a clamping bolt therein, and thus clamping bolts 2 can be joined to fixing screws 5 by screw-engaging the shank 20 of the clamping bolt with the nut portion 52 of the fixing screw. A spike 54 extends from the washer portion 53 in a direction away from the shank 50, so that in use, it pierces the underside of the overlying timber 1, whereby rotation of fixing screw 5 is prevented when the screw-engaged bolt in the overlying timber is rotated. In order to assemble the timber wall, the base timber 1a is placed on the base 4, and fixing screw 5 is inserted into hole 12a, and then fixing screw 5 is screwed into the base 4, so as to provide a firm coupling of base 4 to timber 1a with the washer portion 53 pressing against the underlying timber 1a. After this, sealing strips 6 are affixed to tongues 10 and a caulking compound is provided along the upper surface of timber 1a. Then, the first-storey timber 1 is placed on top of the base timber 1a, and clamping bolt 2 is inserted into hole 12 at each fixing location. Clamping bolt 2 is engaged with screw 5 by engagement of the screw-threaded shank region 21 of the bolt 2 and the internally screw-threaded recess 55 of the screw 5, and thus timbers 1a and 1 are fixedly secured together. In a similar manner, the second storey timber is fixedly secured to the first storey timber, after the sealing strip 6 and the caulking compound 7 have been applied in the same manner as described above. The timbers are stacked one on top of another and secured until the final-storey timber is provided to form a wall of the desired height. The sealing strips 6 existing between each timber are pressed down effectively by the tightness of the clamping bolts 2, and the gap between each timber is eliminated. After the timber house has been built, the timbers 1a and 1 shrink as they dry. Even when the timbers become dry and shrunk, the lower surface of each timber is engaged and supported by the washers 23 and 53 of the clamping bolt 2 or the fixing screw 5 respectively. Since there is no corresponding shrinkage of bolts 2 and screws 5, the shrinkage effect is only imposed on a single timber, avoiding the formation of large gaps which is a disadvantage of prior-art methods. As a result, the maximum shrinkage of the timber wall is equal to the shrinkage of a single timber, requiring only a small slide adjusting device to adsorb the shrinkage of the single timber and a small settling space. If there is a large shrinkage of the timbers because of insufficient drying prior to or during construction, there will be an extensive gap between the nut portion 22 and the wall of hole 12. In this case, the weight of the timber wall is supported only by the clamping bolt 2 and there is a risk that the clamping bolt 2 may be buckled. Various methods of preventing this buckling are now explained in accordance with Figs 10 to 13. Referring to Fig 10, the diameter of the unthreaded region of shank 20 in clamping bolt 2 is made almost the same size as hole 12, so that the outer circumference of shank 20 may be in contact with the wall of hole 12. In other words, by this contact, the gap is now eliminated to prevent the bolt 2 from being buckled. Referring to Fig 11, a buckling-prevention plate 8 extends around the shank 20. The diameter of plate 8 is almost equal to the diameter of hole 12, so the gap is eliminated to prevent the clamping bolt 2 from being buckled. Referring to Figs 12 and 13, a filler 9 is supplied in the gap between the shank 20 and hole 12, and so the gap is eliminated by the filler 9 to prevent the clamping bolt 2 from being buckled. In Fig 12, the filler 9 is a cylindrical pad, while in Fig 13 the filler is sand. The filler 9 is not limited to sand or a cylindrical pad, but may be any material of the required strength. Advantageously, a timber wall constructed by the method of this invention, is easily disassembled, a piece at a time, since each clamping element 2 or 5 fixes in place only a single timber. During disassembly, the spikes 24 or 54 of the underlying clamping element 2 or 5 into which the shank 20 of the clamping bolt 2 being removed is engaged, pierce the overlying timber, which ensures that there is no rotation of that clamping element, thereby facilitating easy disassembly. This invention limits the effects of accumulated timber shrinkage in a timber wall to the amount of shrinkage occurring in a single timber. Thus, the invention achieves the minimum ratio value of the imposed shrinkage thereof. It is to be understood by those skilled in the art that the foregoing description is a preferred embodiment of the disclosed method and device, and that various changes and modifications may be made in the invention within the scope thereof as defined by the appended claims.

Claims: A method of assembling a timber wall (3) for a timber house comprising, at a fixing location, the steps of:- a) securing a base-timber (1a) to a base (4) by means of a fixing screw (5) having a screw-threaded shank (50), the shank (50) having a tapered, screw-threaded region (51), extending through a hole (12a) in the base timber (1a) and engaging in the base (4), said fixing screw (5) having a head including an internally threaded nut portion (52), and a washer (53) which is disposed between the nut portion (52) and the shank (50) and which presses down against the underlying base timber (1a), b) locating another timber (1) on the base timber (1a), c) securing said another timber (1) to the base timber (1a) using a clamping bolt (2) having a screw-threaded shank (20) passing through a hole (12) in said another timber (1) and engaging the nut portion (52) of the fixing screw (5), said clamping bolt (2) having a head including an internally screw-threaded nut portion (22), and a washer (23) which is disposed between the nut portion (22) and the shank (20) and which presses down against said another timber (1) beneath it, and d) locating and securing each of further successive timbers on the underlying timbers using further clamping bolts in an analogous manner to steps (b) and (c) until the resultant wall is of the required height. The method according to claim 1, characterised in that the shank, nut portion and washer of the fixing screw (5) and/or clamping bolt (2) are of unitary construction. The method according to claim 1 or claim 2, comprising the further step of providing between adjacent timbers (1,1a) at least one sealing strip (6), so that when the clamping bolt (2) or screw (5) is tightened to clamp the timber (1,1a), said at least one sealing strip (6) is forcibly compressed to provide a seal between the timbers (1,1a). The method according to any preceding claim, comprising the further step of providing a caulking compound between adjacent timbers (1,1a). The method according to any preceding claim, comprising the further step of providing means for preventing the clamping bolt (2) and/or fixing screw (5) from being buckled in a gap between the shank (20,50) and the wall of the respective hole (12,12a). The method according to claim 5, characterised in that said buckling-prevention means comprises an enlarged diameter region of the shank of the clamping bolt (2) and/or fixing screw (5). The method according to claim 5, characterised in that said buckling-prevention means comprises a filler (9) in the gap between the clamping bolt (2) and/or fixing screw (5) and the wall of the respective hole (12,12a). The method according to claim 7, characterised in that said filler (9) is sand. The method according to claim 7, characterised in that said filler (9) is a cylindrical pad. The method according to claim 5, characterised in that said buckling-prevention means comprises a plate (8) extending around the shank (20,50) of said clamping bolt (2) and/or fixing screw (5). The method according to any preceding claim, characterised in that the washer (23,53) is equipped with a claw or spike (24,54) which pierces the underside of the overlying timber (1) so as to secure it in position and prevent rotation of the clamping bolt or fixing screw (2,5) with which it is associated when the bolt (2) in the overlying timber (1) is rotated. A clamping element (2,5) for use in the method according to claim 11, comprising a shank (20,50) having a screw-threaded region (21,51), a head, having an internally threaded nut portion (22, 52), said nut portion (22, 52) having an internally threaded recess (25, 55) for receiving a screw-threaded shank (21, 51) of another clamping element (2) and a washer (23,53) disposed between said shank (20,50) and said head, wherein the washer (23,53) has a claw or spike (24,54) projecting in a direction away from the shank (20,50). A clamping element according to claim 12, characterised in that the shank (20,50), head (22,52) and washer (23,53) are of unitary construction. A clamping element according to claim 12 or 13, which is a fixing screw (5), and wherein the shank (50) has a tapered screw-threaded region (51). A clamping element according to claim 12 or 13, which is a clamping bolt (2), and wherein the shank (20) has a screw-threaded region (21) engageable with the internally threaded recess (25,55) of another clamping element (2,5) . A clamping element according to any of claims 12 to 15, characterised in that a plate (8) extends around said shank (20,50) of said clamping element (2,5) . A clamping element according to any of claims 12 to 16 constructed and adapted to be used in the method of any one of claims 1 to 11. A kit of parts adapted to be used in a method as claimed in any one of claims 1 to 11, comprising:- a plurality of timbers (1,1a); a plurality of fixing screws (5) each having a shank (50) with a tapered screw-threaded region (51), a head including an internally threaded nut portion (52), and a washer (53) which is disposed between said head and said shank (50) and; a plurality of clamping bolts (2) each having a shank (20) with a screw-threaded region (21), a head including an internally screw-threaded nut portion 22, and a washer (23) which is disposed between said head and said shank (20).

Inventors: FUTAGI KOHZOH, FUTAGI, KOHZOH, FUTAGI, KOHZOH, C/O R.C. CORE CO., LTD.
Applicants: R C CORE CO LTD, R.C. CORE CO., LTD.
Application year: 1996
Main classification: E04B2
IPC codes: E04B2, E04B1, F16B35