Fixture for building boards, a building board having the fixture fixed thereto, and the method of fastening the building boards

A plurality of engaging pieces each formed of washer (35) for instance are fixed to the rear surface of a building board (30). A plurality of elongated fixtures (10), each provided at the lower end thereof with an engaging tongue (20a) and at the upper end thereof with an engaging region (12a) designed to be engaged with the engaging tongue (20a), are engaged with the engaging pieces. The fixtures (10) thus engaged are directly fixed to the posts (1) or studs (2) of a building. Since each fixture (10) is provided with a rising portion (12), a ventilation space (Sc) is secured between the framework of the building and the rear surface of a building board (30). The coupling between upper and lower building boards (30) can be effected through the linkage between a couple of fixtures (10). Since the engaging tongue (20a) is made separable from the building board (30), the building boards (30) can be transported for instance without becoming bulky.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of fastening flat building boards such as ceramic siding boards to the framework of a building, and to a building board as well as a fixture, which are suited for use in the fastening method.

2. Description of the Related Arts

In an exterior finish work of a building, ceramic siding boards (building boards) are employed for attaching them to the sidewall of a building. For example, in a horizontal board siding work where the building boards are attached to the frame construction with the longitudinal direction of the building boards being directed in the lateral direction (horizontal direction), moisture permeable waterproofing sheets3are attached at first to the vertical framework consisting of posts1and studs2, and then, for the purpose of securing a ventilating space, furring strips4are attached via the moisture permeable waterproofing sheets3to the framework, the positions these furring strips4being aligned with the positions of the posts1and studs2as shown in FIG.17. Thereafter, building boards (not shown inFIG. 17) are fastened to the furring strips4by means of nailing for instance.

On the other hand, in a vertical board siding work where the building boards are attached to the frame construction with the longitudinal direction of the building boards being directed upright (vertical direction), after the moisture permeable waterproofing sheets3are attached to the posts1and studs2, furring strips5are horizontally attached via the moisture permeable waterproofing sheets3to the framework, thereby placing the furring strips5at several stages with a predetermined space being secured between each neighboring stages as shown in FIG.18. In this case, a space S is required to be formed between the furring strips5which are disposed side by side in horizontal direction so as to secure a passageway for ventilation.

In the meantime, as an alternative method of fastening building boards to the framework where the aforementioned nailing is not employed, there is known a method of fastening the building boards by making use of a metallic fixture60which is exclusively dedicated for the building boards as shown in FIG.19. This metallic fixture60is constructed such that the contacting face portion61athereof facing the framework is disposed parallel with and spaced away by a predetermined distance from the supporting face portion61bthereof for supporting the rear surface of a building board, said predetermined distance being secured by the existence of the connection portion61cand bent portion61dof the metallic fixture60. A mounting portion62extending horizontally is projected from the supporting face portion61b, thereby permitting the shiplap portions of a couple of the neighboring upper and lower building boards30A and30B to be fitted therein and engaged with each other, the shiplap portions being formed respectively on the horizontal edge portions31A and31B, facing each other, of the neighboring upper and lower building boards30A and30B (see also FIG.20).

When this metallic fixture60constructed as mentioned above is employed, it is possible to secure a sufficient ventilating space Sc between the framework and the rear surface of a building board due to the presence of the metallic fixture60which has been attached to the furring strips4.FIG. 20illustrates a horizontal board siding work of building boards30by making use of the metallic fixture60. Namely, the installation of the building boards20can be performed as follows.

First of all, the lowermost building board30B is horizontally positioned. Then, the upper horizontal edge portion31B of the lowermost building board30B is permitted to engage with the underside portion of mounting portion62of the metallic fixture60, thereby positioning the metallic fixture60. Then, the metallic fixture60is fixed, by means of screws or nails50, to the furring strips4or to the posts1or studs2via the furring strips4. Then, the lower horizontal edge portion31A of the next upper building board30A is permitted to engage with the upper side portion of mounting portion62of the metallic fixture60that has been fixed in advance, thereby horizontally positioning this upper building board30A. Then, in the same manner as described above, the upper horizontal edge portion31B of this building board30A that has been horizontally positioned is permitted to engage with the underside portion of mounting portion62of another metallic fixture60, and then, this metallic fixture60is fixed to the posts1or studs2by means of screws or nails50. Thereafter, the same procedures as described above are repeated to attach the building boards30horizontally and in multistage to the side of a building, thereby accomplishing a decorative external sidewall.

This fastening method is advantageous in that there is little possibility of damaging the surface of the building boards30as seen in the case of the fastening work by way of nailing, and that the existence of the metallic fixture60cannot be externally recognized, thus making it possible to provide a fastened state of building boards which is very excellent in external appearance. Further, since a sufficient ventilation space Sc can be secured on the rear side of the building boards30that have been fastened to the framework, it is possible to inhibit the generation of dew on the rear surface of the building boards30.

As described above, in the case of the fastening work of building boards by way of nailing, the nailing is generally limited to only the periphery of a building board, so that unless the nailing is performed strictly following a predetermined specification, it may become difficult to realize a sufficient wind pressure withstanding strength. Additionally, a touch-up coating for the head portion of nail is required to be performed, thus leaving an aesthetic problem.

On the other hand, in the case of the fastening method using the aforementioned metallic fixture, a large number of the furring strips4are required to be disposed in order to secure the ventilation space Sc. Therefore, the work load for attaching the furring strips4becomes enormous, giving a large influence to the working cost and working period. Additionally, in the case of using the aforementioned metallic fixture, the work for attaching a large number of metallic fixtures to the posts1or studs2is required.

In the case of a horizontal board siding work, the metallic fixture to be employed is constructed so as to be fitted with the shiplap joint portions (overlying tongue portion and underlying tongue portion) of building boards which are respectively formed on the upper and lower horizontal edge portions of each building board. Therefore, when a large surface load (such as wind pressure) is imposed on the front surface or rear surface of the building boards that have been fastened, the load is required to be endured by the metallic fixtures that have been disposed at the top and bottom sides of a building board. Since each piece of the building boards available in the market at present is relatively small in surface area, the employment of aforementioned metallic fixture for fastening such building boards would not raise any serious inconvenience. However, if the aforementioned conventional metallic fixture is employed for fastening a building board having a much larger surface area which is expected to be placed in the market in near future, it would become difficult to sufficiently endure the load of such a large building board by means of only the metallic fixtures being disposed at the top and bottom side edges of a building board, thus raising a possibility that the fastening portion of metallic fixture would be damaged by a large surface load.

SUMMARY OF THE INVENTION

The present invention has been made in view of the aforementioned circumstances, and therefore, an object of the present invention is to provide a novel fastening method of flat building boards which makes it possible to more easily perform the fastening work of building boards by way of so-called direct siding work wherein the building boards are enabled to be directly fastened to the posts and studs (structural framework) without employing furring strips, and which is capable of easily securing a sufficient ventilating space between the framework of a building and the rear surface of a building board, thus greatly contributing to the labor saving in the fastening work of building boards.

Another object of the present invention is to provide a novel fastening method of flat building boards which is designed such that even if an unexpected load (surface load) is imposed on the front surface or rear surface of a building board being fastened to the framework of a building, it is possible to prevent the load from being excessively concentrated on the joint portion between neighboring building boards, thereby preventing even a building board of large surface area from becoming unstable in the fastened state thereof.

A further object of the present invention is to provide a novel building board which can be handled in the same way as the conventional building board on the occasion of for example transporting the building board to a work site in spite of the fact that a special member for performing the aforementioned fastening method is attached to the rear surface of the building board.

With a view to realize the aforementioned objects, the present invention provides a method of fastening a building board to the framework of a building, the method being characterized in that a building board having a flat plate-like configuration and provided on the rear surface thereof with engaging protrusions and an elongated fixture which is adapted to be detachably engaged with the building board are employed, and that the building board is assembled in advance together with the elongated fixture through an engagement between the engaging protrusions and the elongated fixture, and then the elongated fixture is fixed to the framework of a building, thereby fastening the building board to the framework of a building.

According to the method of the present invention, the flat plate-like building board provided on the rear surface thereof with engaging protrusions and the elongated fixture to be engaged with the building board can be separately manufactured and transported to a work site. Further, since the height of the engaging protrusions can be confined to a relatively low level, a large number of building boards can be piled up one upon another with a thin buffering sheet being interposed between the building boards and transported in such a piled state without inviting any inconvenience. With respect to the fixture, since it is elongated in configuration, a large number of fixtures can be bundled together on the occasion of the transportation thereof.

In the work site, the fixture is engaged with the building board by taking advantage of the engaging protrusions attached to the rear surface of the building board. Preferably, a plurality of fixtures are attached to the building board along the longitudinal direction of the building board. While keeping this state where the fixtures are attached to the building board, each of the fixtures is partially fixed to the framework of a building (preferably, the vertical members such as the posts and studs of framework), thereby directly and easily fastening the building boards to the framework of a building (direct siding work).

As for the building board per se, it may be the same as those conventionally employed. A member which is capable of functioning as the aforementioned engaging protrusion, preferably an engaging piece such as a locking washer is fixed to plural portions of the rear surface of the building board by making use of a driving rivet whose tip opens while being driven which can be knocked into the rear surface of the building board. This fixing work using the locking washer can be easily performed at a building board-manufacturing factory, and therefore the board-siding work in the work site can be prevented from becoming complicated. Furthermore, since it is relatively easy to confine the height of the engaging protrusion such as the aforementioned engaging piece to several millimeters as measured from the rear surface of the building board, the presence of the engaging protrusion would not become any substantial obstruction in the transportation of the building boards.

The fixture according to the present invention is preferably constructed such that it comprises a main body which is designed to be entirely or partially contacted with the rear surface of a building board; engaging holes formed in the main body; a first rising portion formed at one end in the longitudinal direction of the main body; an engaging region formed at or near the first rising portion; an extension portion extending from the distal edge of said first rising portion in a direction away from and parallel with said main body; and an engaging tongue formed at the other end in the longitudinal direction of the main body; wherein said engaging tongue is positioned and shaped such that it can be inserted into said engaging region of the fixture attached to a neighboring building board as a couple of building boards each having the fixture attached to the rear surface thereof are positioned neighboring in vertical direction.

More preferably, the engaging holes should preferably be consisted of a first opening which is large enough to allow the engaging piece fixed to the rear surface of a building board to pass therethrough, and a second opening which is not large enough to allow said engaging piece to pass therethrough and is formed integral with said first opening.

On the occasion of fastening work of building boards, a large number of building boards each having the fixture attached to or engaged with the rear surface thereof are prepared at a work site. Then, the building board (a first building board) to be disposed at a lower level is fastened at first to the framework of a building by taking advantage of the fixture attached to or engaged with the rear surface of the building board. Then, the next building board (a second building board) to be disposed over the first building board is placed along the upper horizontal edge of the first building board and fastened to the framework of a building by inserting the engaging tongue of the fixture attached to or engaged with the rear surface of the second building board into the engaging region formed in the fixture of the first building board. As a result, these lower and upper building boards can be fastened contiguous with each other in the vertical direction and in a state wherein a couple of elongated fixtures engaged respectively with the rear surface of the building board are coupled with each other.

As for the specific configuration of the engaging region of the fixture, it may be optionally selected as long as it is configured such that the engaging tongue of the fixture attached to the rear surface of the neighboring upper building board can be introduced therein and that once the engaging tongue has been introduced into the engaging region, the fixture can be hardly disengaged from the engaging region by a load imposed thereon and directed forward (toward the building board).

For example, the engaging region of the fixture may be an opening formed in the first rising portion and designed so as to enable the engaging tongue to be introduced therein, or may be a region at one end in the longitudinal direction of the main body where the first rising portion is not located if the first rising portion is formed narrower than the width of the main body. In the latter case, the engaging tongue is allowed to be introduced into the rear side of the region where the first rising portion is not located, thereby realizing a desired engaging state.

According to this invention, the main body of the fixture may be provided on both sides thereof with a reinforcing member. This reinforcing member may be formed by bending a portion of the main body or by welding a separate member to the main body so as to integrate the separate member with the main body. When the fixture is provided with this reinforcing member, the flexural rigidity of fixture can be improved, thereby making it possible to reliably prevent the building board from being deformed by a back pressure. Further, the reinforcing member secures a ventilation space. The height of the reinforcing member should preferably be the same level as that of the extension portion. When the height of the reinforcing member is set to as mentioned above, the distal edge of the reinforcing member can be contacted with the framework of a building, thereby enabling the reinforcing member to reliably support the back face of a building board.

According to the present invention, the building board is provided on the rear surface thereof with a large number of the aforementioned engaging pieces which are arranged at predetermined intervals so as to enable a plurality of fixtures to be engaged therewith and spaced apart from each other in conformity with the intervals of the vertical members of the framework of a building. When the building board is constructed in this manner, the strength of the building board after the attachment thereof to the framework of a building can be reliably improved.

According to another embodiment of the present invention, the engaging protrusion is not attached at all to the building board, and instead, the fixture is fixed to the building board by making use of a driving rivet, etc. In this case, the fixture is fixed to the rear surface of a building board with at least the extension portion thereof being protruded from the peripheral edge of the building board. Preferably, a plurality of fixtures are fixed to the rear surface of a building board at predetermined intervals so as to conform with the intervals of the vertical members such as the posts and studs of the framework of a building to which the building board is to be fastened. As for the fixing method of the fixture to the building board, there is not any particular limitation. However, where the building board is a ceramic building board, a fixing method employing a driving rivet whose tip opens while being driven would be advantageous in the respects that the fixing work can be facilitated and that a more stabilized fixed state can be obtained. As an alternative method, it is also possible to employ an adhesive or to mold the fixtures integral with the building board on the occasion of manufacturing the building board.

The fastening of the building board according to this embodiment to the framework of a building can be performed in the same manner as in the case of the building board wherein the fixtures are engaged with the building board.

According to the building board-fastening method of the present invention, since the fixtures engaged with the rear surface of a building board are directly fixed to the framework of a building, so that as compared with the building board-fastening method employing a conventional metallic fixture, the work of fixing a large number of metallic fixtures can be omitted, thereby greatly saving the labor in the execution of the fixing work at the work site. Further, due to the provision of the rising portion formed at one end of the fixture, a sufficient ventilation space can be secured between the framework of a building and the rear surface of a building board. Therefore, the furring strips which are required in the conventional siding work can be entirely omitted, thus resulting in the simplification of work and labor saving.

Furthermore, since the fixture is elongated in configuration, and a plurality of fixtures are engaged with or fixed to the building board in such a manner that the fixtures are arrayed along the longitudinal direction of the building board with the main body of the fixture being directly contacted with the rear surface of a building board, the mechanical strength of the building board can be greatly enhanced, and even if the building board is of large surface area, it is possible to ensure a stable fastened condition of the building board. Further, even if a large magnitude of surface load is imposed on the rear surface of a building board that has been fastened to the framework of a building, the load can be mainly born not by the upper and lower horizontal edges of the building board but by the joint portion between neighboring fixtures (or the engaging portion between the engaging tongue and the engaging region) or by the engaging portion between the engaging protrusion attached to the rear surface of a building board and the fixture (or the engaging portion between the engaging protrusion and the engaging hole). Therefore, the shiplap joint portions (overlying tongue portion and underlying tongue portion) of building boards which are respectively formed on the upper and lower horizontal edge portions of each building board would not be substantially affected by such a surface load. As a result, the shiplap joint portions of building boards can be prevented from being damaged.

As described above, although there is not any particular limitation with respect to the raw material of the building board to be fastened, the employment of a ceramic building board is very effective as a building board to be fastened by making use of the fastened structure according to the present invention in view of the fact that a building board of large surface area is vulnerable to cracking due to a surface load. It is preferable that four sides or at least top and bottom horizontal sides of a building board should be respectively formed into a shiplap configuration in view of preventing rain water from penetrating through the joint portion between the neighboring building boards fastened in this manner.

The method of fastening building boards according to the present invention is advantageous in that it can be applied to any desired vertical members of a building. In particular, when the building to be worked is formed of a wooden framework like wood frame construction (two-by-four construction) or framework construction, or formed of an iron framework, the building boards can be easily and reliably installed by taking advantage of the vertical members constituting these frameworks.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferable embodiments of the present invention will be explained in details below with reference to the drawings.

A building board30shown inFIG. 1aper se may be the same as the conventional ceramic building boards which are adapted to be fastened to the framework of a building in the siding work of a building. If required, a rabbet joint-forming work may be conducted on all four sides of a building board for enabling the shiplap joint of building boards to be achieved.

The building board30is provided on the rear surface thereof with a plurality of engaging washers (engaging pieces)35constituting one example of “engaging protrusion” as defined by the present invention and arranged at predetermined intervals “h”. Namely, as shown inFIG. 1a, a plurality of engaging washers35are fixed at predetermined intervals “h” to the rear surface of the building board30so as to form a linear array thereof traversing the width of the building board30. This array of the washers is repeatedly formed along the longitudinal direction of the building board30, the interval between the arrays being conformed with the intervals W between the posts1and studs2of the framework of a building, to which the building board30is designed to be attached. By the way, the arrays of washers may be formed so as to conform in location with every posts and studs, or conform with only some of the posts and studs.

The engaging washers35in this embodiment is circular in plan view, and as shown inFIG. 1b, the central portion of the washers35is formed into a recessed portion36having a flat back surface. A hole37is formed at the center of the recessed portion36so as to allow a clamping screw or a rivet to be introduced therethrough for fixing the washers35to the rear surface of the building board30.FIG. 2illustrates the procedure for fixing the washers35to the rear surface of the building board30by making use of, for example, a driving rivet40whose tip opens while being driven. As shown inFIG. 2a, in the embodiment illustrated herein, bottomed holes31are formed in advance at predetermined locations of the rear surface of the building board30. First of all, the washer35is positioned on the rear surface of the building board30in such a manner that the hole37of the washer35is aligned with the bottomed hole31. Then, as shown inFIG. 2b, the driving rivet40whose tip opens while being driven is set inside the bottomed hole31through the hole37.

Then, the driving rivet40set in this manner is knocked down into the bottomed hole31by making use of a driving machine (not shown). As a result, the tip-end41of the driving rivet40is caused to expand and thrust into the building board30. As a result, the recessed portion36of the washer35is clamped and immobilized between a rivet head42and the rear surface of the building board30, thus fixing the washer35to the rear surface of the building board30. When the washer35is fixed to the rear surface of the building board30in this manner, a space P is formed between the peripheral portion of washer35around the recessed portion36and the rear surface of the building board30. After the washer35is clamped to the rear surface of the building board30by making use of the rivet40, the supporting rod43of the rivet40is removed by any suitable means (FIG. 2c), thereby finishing the fixing work of the washer35to the rear surface of the building board30(FIG. 2d). In the same manner as illustrated above, the fixing of the washer35to predetermined locations of the rear surface of the building board30is repeated, thereby forming the building board30of the present invention as shown inFIG. 1a.

As shown inFIGS. 1 and 2, the building board30attached with the washer35has a thickness which is increased by the thickness of the washer35. However, since this increment is limited in magnitude and the projected portions are substantially uniformly dispersed throughout the entire rear surface of the building board30, a large number of building boards can be stably piled up one upon another with a thin buffering sheet (not shown) being interposed between the building boards on the occasion of transporting the building boards30. Further, even if the building boards30are piled up in this manner, the height thus piled (thickness-wise direction) of the building boards30would not be substantially increased.

Next, the elongated fixture10having, as an engaging protrusion, the washer35engaged therewith will be explained.FIG. 3shows a perspective view illustrating the one example of the fixture10. The fixture10is entirely formed of steel, and comprises a flat main body11, a rising portion12which is extended from the upper end of the main body11and bent backward by a predetermined angle, and an extension portion13extending from the distal edge of the rising portion12in a direction away from and parallel with the main body11(upward direction). Both rising portion12and extension portion13are formed to have a narrower width as compared with the width of the main body11and are located coaxial with the main body11. Therefore, on both sides of the rising portion12, there are formed a pair of cut-out regions12a. Further, the extension portion13is provided with a locking hole18.

On both sides of the main body11, there are formed a pair of bent portions11awhich are extended backward from the both sides of the main body11. These bent portions11aare capable of functioning as a reinforcing member for the main body11. The level of the distal end11bof the bent portions11a(i.e. the height of the reinforcing member) should preferably be substantially the same as the level of the rear surface of the extension portion13. When the height of the bent portions11ais set to as mentioned above, the distal end11bof the bent portions11acan be contacted with the framework of a building, thereby enabling the bent portions11ato reliably support the back face of the building board being fastened.

A couple of engaging tongues20aare extended from both edge portions of the lower end of the main body11and are bent backward by a predetermined angle. In this case, the interval between this couple of engaging tongues20ais made somewhat larger than the lateral width of the rising portion12. Although it is not essential, a bent portion21is extended from the central portion of the lower end of the main body11and inclined forward. As explained hereinafter, the lower edge portion of the building board30is designed to be mounted on this bent portion21on the occasion of attaching the fixture10to the building board30, thereby determining the positioning between the building board30and the fixture10.

Furthermore, the main body11is provided with a plurality of engaging holes19which are designed to be detachably engaged with the washers35fixed to the rear surface of the building board30, thereby enabling the elongated fixture10to be detachably engaged with the building board30. Each of the engaging holes19is consisted of a first opening19awhich is large enough to allow the engaging washer35fixed to the rear surface of the building board to pass therethrough, and a second opening19bwhich is not large enough to allow the engaging washer35to pass therethrough and is formed integral with the first opening19a.

As shown inFIG. 3, Each of the engaging holes19is configured such that the upper portion thereof or the side which is closer to the extension portion13is constituted by the first opening19a. By the way, the interval “h” between the engaging holes19is made identical with the interval “h” (in the direction traversing the width of the building board30) of the engaging washers35which are fixed to the rear surface of the building board30.

The fixture10is constructed such that the length of the main body11is made substantially identical with the width of the building board30to be fastened, and the height of the rising portion12is optionally determined depending on the magnitude of ventilation space desired to be formed as the building board30is fastened to the framework of a building.

The fixture10can be engaged with the rear surface of the building board30as follows. First of all, as shown inFIG. 4, the fixture10is placed near the rear surface of the building board so as to align the fixture10with the array of washers35fixed to the rear surface of the building board. In this case, the position of each of the first openings19aof the fixture10is aligned with the position of each of the washers35(FIG. 4a). Under this condition, the fixture10is shifted toward the rear surface of the building board30so as to allow the washer35to pass through the first openings19a, thereby causing the rear surface of the fixture10to be contacted with the rear surface of the building board30. Under this condition, the fixture10is lifted upward so as to allow the peripheral portion of the second opening19bof engaging hole19to be introduced into the space P formed between the rear surface of the washer35and the rear surface of the building board30. As a result, the fixture10is engaged with the rear surface of the building board30(FIG. 4b).

The engaging position of the fixture10in the longitudinal direction thereof may be regulated by the position where the lower brim portion of the second opening19bis contacted with the recessed portion36of the washer35. Alternatively, when a bent portion21is provided at the lower end of the main body11of the fixture10as mentioned above, the positioning of the fixture10may be regulated by mounting the lower edge of the building board30being fastened on the bent portion21. According to the latter method, a positioning of higher precision can be realized. In either cases, the positioning of the fixture10is performed in such a manner that at least the hole18portion of the extension portion13is protruded from the upper edge of the building board30after the building board30has been engaged with the building board30.

In the same manner as described above, a required number of fixtures10are attached to the building board30along the longitudinal direction of the building board30. In this case, as shown inFIG. 5, the fixture10may be engaged with all of the arrays of washers or with some of the arrays of washers as required. The number of the fixture10can be suitably selected depending on the fastening strength of the building board to the framework of a building or on the layout of the vertical members of the framework of a building.FIG. 5shows a state wherein the building board30having the fixtures10engaged therewith is fastened to the framework of a building.

The building board30engaged, through the rear surface thereof, with a required number of the fixtures10can be fastened to the framework of a building as follows. First of all, as shown inFIG. 5, the building board30(30B) to be disposed at a lower position is arranged in such a manner that the positions of the fixtures10is aligned with the positions of posts1and studs2, and then, the building board30is pushed toward the framework of a building so as to allow the extension portions13of the fixtures10to be contacted with the posts1and studs2. Under this condition, a screw50is screwed, through the hole18formed in the extension portion13, into the post1or stud2, thereby fixing the fixtures10to the posts1and studs2. After all of the fixtures10attached to a single building board30B have been fixed the posts1or studs2, another building board30B is disposed on one side of the building board30B that has been fastened to the posts1or studs2, and the same fastening work as described above is repeated.

Then, the fastening work of upper building board30A is performed. First of all, the positions the fixtures10of the upper building board30A are aligned with the fixtures10of the lower building board30B. Then, under this condition, the lower horizontal edge (overlying tongue portion) of the upper building board30A is placed on and along the upper horizontal edge (underlying tongue portion) of the lower building board30B. As a result, a couple of engaging tongues20aformed contiguous with the lower end of each of the fixtures10of the upper building board30A are allowed to be introduced into a pair of cut-out regions12aformed on both sides of the rising portion12of the fixtures10of the lower building board30B. As a result, the fixtures10of the upper building board30A are coupled with the fixtures10of the lower building board30B (see FIG.6).

Under this condition, the upper building board30A is firmly pressed against the framework of a building so as to allow the extension portions13of the fixtures10to be contacted with the posts1and studs2. Under this condition, a screw50is screwed, through the hole18formed in the extension portion13, into the post1or stud2in the same way as in the case of the lower building board30B, thereby fixing the fixtures10to the posts1and studs2. Thereafter, a required number of building boards are fastened side by side or one upon another in the same manner as explained above, thereby constructing a decorative wall of a building according to the present invention.

As explained above, according to the aforementioned fastening method, since a sufficient space (a ventilating space Sc) can be secured between the framework of a building and the rear surface of the building board30without employing furring strips (i.e. even though the building boards are directly fastened to the structural framework), the fastening work of building boards can be performed, greatly saving the labor for the work.

Furthermore, since the fixture10is elongated in configuration, and a plurality of fixtures10are attached, through an engagement between a plurality of engaging holes19and the washers35fixed to the rear surface of the building board30, to the building board30in such a manner that the fixtures30are arrayed along the longitudinal direction of the building board with the main body of the fixture being directly contacted with the rear surface of the building board30, the mechanical strength of the building board30can be greatly enhanced. As a result, even if the building board30is of large surface area, it is possible to ensure a stable fastened condition of the building board30.

Furthermore, even if a surface load is imposed on the rear surface of the building board30that has been fastened to the framework of a building, the load can be mainly born not by the upper and lower horizontal edges of the building board30but by a plurality of the engaged portions between the engaging holes19(the second opening19b) and washers35and by the joint portions between the fixtures10. Therefore, the shiplap joint portions (overlying tongue portion and underlying tongue portion) of the building boards30which are respectively formed on the upper and lower horizontal edge portions of each building board would not be substantially affected by such a surface load. As a result, the shiplap joint portions of building boards can be prevented from being damaged.

FIG. 7shows another embodiment of the fixture. This fixture10A comprises a flat main body111, a first rising portion112which is extended from the upper end of the main body111and bent backward by an angle of 90 degrees, and an extension portion113extending from the distal edge of the first rising portion112in a direction away from and parallel with the main body111(upward direction).

A couple of second rising portions114aand114bare extended from both distal edge portions of the extension portion113and are bent forward (toward where the main body111is located), thus extending substantially parallel with the first rising portion112. Additionally, a couple of sustaining planes115aand115bare formed contiguous respectively with the distal edge portions of the second rising portions114aand114band bent downward by an angle of 90 degrees so as to make the sustaining planes115aand115bsubstantially flush with the rear surface of the main body111. The distal end of each of the sustaining planes115aand115bmay be further bent toward the extension portion113as shown in FIG.7. As a result, there is formed a cut-out region116between this pair of second rising portions114aand114b, this cut-out region116being extended up to the extension portion113.

Further, the first rising portion112is provided with an opening117having a length which corresponds to the lateral width of the cut-out region116. This opening117corresponds to the “engaging region” as defined by the present invention. Further, a hole118is formed in the extension portion113, and the main body111is provided with a plurality of engaging holes119of the same configuration and in the same manner as illustrated with reference to the fixture10shown in FIG.3.

The main body111is further provided with an engaging tongue120which is extended from the lower end of the main body111and composed of a horizontal portion120awhich is formed contiguous with the lower end of the main body111and bent by an angle of about 90 degrees, and an oblique portion120bwhich is formed contiguous with the distal end of the horizontal portion120aand bent downward by a desired angle. In this case, the lateral width of the engaging tongue120is made somewhat narrower than the length of the engaging hole117formed in the first rising portion112. The extending length of the horizontal portion120ais made substantially identical with the distance where the fore-brim of the engaging hole117is located as measured from the upper edge of main body111.

The manner of employing this fixture10A is the same as illustrated with reference to the fixture10shown in FIG.3. As for the construction of the building board30to be engaged with this fixture10A, it may be the same as illustrated with reference to FIG.1.

However, the employment of this fixture10A is advantageous in the mounting work of building boards as explained below. Namely, on the occasion of positioning the lower horizontal edge (overlying tongue portion) of the upper building board30A on and along the upper horizontal edge (underlying tongue portion) of the lower building board30B, the upper building board30A can be moved downward while allowing the rear surface of the upper building board30A to be guided by a couple of sustaining planes115aand115bwhich are formed contiguous with the second rising portions114aand114bof the fixture10A of the lower building board30B.

When the upper building board30A is mounted on the lower building board30B in this manner, the oblique portion120bof fixture10A fixed to the upper building board30A is kept introduced into the engaging hole117formed in the fixture10A of the lower building board30B, so that both fixtures10A of the upper and lower building board30A and30B can be coupled to each other in a stable manner.

FIG. 8shows a further embodiment of the fixture. This fixture10B differs from the fixture10A shown inFIG. 7in the respect that the second rising portion114is formed of a single flat portion without accompanying the cut-out portion116. Other constituent members are the same as those shown in FIG.7and hence are referred to by the same numbers.

This fixture10B is advantageous in that since the cut-out portion116is not existed therein, the molding work of the second rising portion114can be simplified and at the same time, the mechanical strength of the fixture10B can be improved. On the occasion of coupling a pair of building boards (each carrying the fixtures10B) to each other, the upper building board30A is slightly inclined forward at first and then, allowed to fall down toward the lower building board30B. As a result, a couple of fixtures10B can be easily coupled to each other (the engagement between the engaging tongue120and the engaging hole117). Thereafter, the upper building board30A is pressed against the framework of a building, thereby allowing the lower end of rear surface portion of the upper building board30A to be supported by the sustaining plane115formed contiguous with the second rising portion114of the fixture10attached to the lower building board30B, thus advantageously realizing a stable coupled state of the upper and lower building boards.

In the foregoing illustrations, the washer35having a circular configuration in plan view is exemplified as an engaging piece constituting the engaging protrusion of the present invention. However, the engaging piece may be any other configurations other than the washer35as long as it is capable of securing a predetermined space P between the engaging piece and the rear surface of a building board and also capable of detachably engaged with the engaging hole19formed in the fixture10. For example, it may be an engaging piece35A having a rectangular configuration in plan view as shown inFIG. 1c.

FIG. 9shows a further embodiment of the fixture. This fixture10C differs from the fixture10A shown inFIG. 7in the respect that a hole121is substituted for the engaging hole119. Other constituent members are the same as those shown inFIG. 7, and hence the explanation thereof is omitted by referring them by the same numbers.

FIG. 10shows the building board30carrying the aforementioned fixtures10C which are fixed to the rear surface of the building board30. As shown inFIG. 10, a plurality of fixtures10C are fixed to the rear surface of the building board30in such a manner that the region of the hole118formed in the extension portion113is protruded from the upper edge of the building board30and that the fixtures10C are spaced apart from each other by a predetermined interval. The aforementioned interval of the fixtures10C may be suitably determined depending on the intervals of the posts1or studs2of a building to which the building board30is to be fastened. Further, the fixtures10C may be positioned and fixed to the building board in conformity with all or some of the posts1or studs2of a building.

Although there is not any particular limitation with respect to the fixing method of fixture, the employment of a driving rivet40whose tip opens while being driven is preferable.FIG. 11illustrates the procedure for fixing the fixtures10C to the rear surface of the building board30by making use of the driving rivet40whose tip opens while being driven. As shown inFIG. 11a, bottomed holes31are formed in advance at predetermined locations of the rear surface of the building board30where the holes121are located as the fixture10C is positioned at the fixing position thereof. First of all, the fixture10C is positioned over the rear surface of the building board30in such a manner that the holes121thereof are aligned with the bottomed holes31. Then, as shown inFIG. 11b, the driving rivet40whose tip opens while being driven is set inside the bottomed hole31through the hole121.

Then, the driving rivet40set in this manner is knocked down into the bottomed hole31by making use of a driving machine (not shown). As a result, the tip-end41of the driving rivet40is caused to expand and thrust into the building board30as shown inFIG. 11c. As a result, the flat main body111of the fixture10C is clamped in an immobilized state between a rivet head42and the rear surface of the building board30. Thereafter, the supporting rod43of the rivet40is removed by any suitable means (FIG. 11c), thereby finishing the fixing work of the fixture10C to the rear surface of the building board30(FIG. 11d).

The fastening of a building board carrying a desired number of the fixtures10C to the framework of a building can be conducted in the same manner as illustrated above with reference to the fastening of a building board carrying the fixtures10A to the framework of a building.FIG. 12is a cross-sectional view wherein the lower building board30B and the upper building board30A are fastened to the post1or stud2.

As described above, according to the aforementioned fastening construction, since a sufficient space (a ventilating space Sc) can be secured between the framework of a building and the rear surface of the building board30without employing furring strips (i.e. even though the building boards are directly fastened to the structural framework), the fastening work of building boards can be performed, greatly saving the labor for the work.

Furthermore, since the fixture10cis elongated in configuration, and a plurality of fixtures10C are attached, under the condition wherein the main body111is closely contacted with the rear surface of the building board30, to the building board30so as to enable the fixtures30to be arrayed along the longitudinal direction of the building board, the mechanical strength of the building board30can be greatly enhanced. As a result, even if the building board30is of large surface area, it is possible to ensure a stable fastened condition of the building board30.

Furthermore, even if a surface load is imposed on the rear surface of the building board30that has been fastened to the framework of a building, the load can be mainly born not by the upper and lower horizontal edges of the building board30but by the joint portions between the fixtures10(the engagement between the engaging tongues120and the engaging holes117). Therefore, the shiplap joint portions (overlying tongue portion and underlying tongue portion) of the building boards30which are respectively formed on the upper and lower horizontal edge portions of each building board would not be substantially affected by such a surface load. As a result, the shiplap joint portions of building boards can be prevented from being damaged.

FIG. 13shows another embodiment of the fixture to be employed for the fastening structure of building boards according to the present invention. This fixture10D differs from the fixture10C shown inFIG. 9in the respect that a wide load-bearing plate117ais positioned along the fore-brim of the engaging hole117formed in the first rising portion112. Other constituent members are the same as those shown inFIG. 9, and hence the explanation thereof is omitted by referring them by the same numbers.

FIG. 14shows a state wherein a couple of building boards each having the aforementioned fixture10D fixed thereto are fastened to each other. As seen fromFIG. 14, even if a surface load is imposed on the rear surface of the building board30that has been fastened to the framework of a building, the load can be born by the contacting surface between the oblique portion120bof the engaging tongue120and the wide load-bearing plate117aformed at the engaging hole117, thus realizing a more stable fastened state of the building board.

FIG. 15shows a further embodiment of the fixture. While the aforementioned fixture10C is provided with a hole121in place of the engaging hole119of the fixture10A shown inFIG. 7, the fixture10E shown inFIG. 15is provided with a hole121in place of the engaging hole119of the fixture10B shown in FIG.8. Other constituent members are the same as those shown inFIG. 8, and hence the explanation thereof is omitted by referring them by the same numbers.

The fastening of a building board carrying the fixtures10E on the rear surface thereof to the framework of a building can be performed in the same manner as in the case of the building board carrying the fixtures10B on the rear surface thereof.FIG. 16shows a cross-sectional view illustrating the manner of falling the upper building board30A toward the lower building board30B under the condition wherein the upper building board30A is slightly inclined forward after the lower building board30B has been fastened to the posts1or studs2.