DESCRIPTION

Technical Field

The invention relates to a connection joint for wood panels of walls and floors of buildings. The invention also relates to a building structure incorporating the joint and a method for making the structure. The invention may be applied in the wooden buildings construction industry, in particular, but not exclusively, for the construction of earthquake- resistant wooden buildings.

Prior Art

The use of wood panels to construct the walls and floors of buildings is known in the construction industry. Wood panels have proved to be particularly suitable for the construction of earthquake-resistant buildings. Conventionally wood panels are held together by means of metal brackets. The brackets are attached to the panels using screws, bolts and similar attachment means. The use of connection joints to join the wooden beams making geodetic roofs together is also known. EP 0 651 099 (A2) describes one example of a connection joint of the abovementioned type. The connection joints are permanently associated to the beams by means of embedded terminal elements. US 6 393 793 (B l) describes one example of a terminal element for beams which is associated to an axial hole made in one of the ends of the beams. The terminal element is bonded into the axial hole and is therefore permanently attached to the beam. US 5 031 371 (A) describes a connector for connecting beams comprising a node and a guide sleeve. The node comprises a plurality of plates provided with holes for the passage of bolts for attaching the plates to the beams; the node also comprises a cylindrical guide sleeve for a bolt. The plates are connected to the cylindrical guide sleeve along the generatrices of the sleeve.

The screws and bolts for attaching connecting brackets do not however ensure that panels are suitably secured. This disadvantage is particularly obvious when the screws or bolts are inserted parallel to the fibres of the wood. In order to overcome this disadvantage resort is often had to a larger number of screws or bolts, which nevertheless weaken the structure of the panel. In addition to this, should there be movements in a building due to an earthquake these means of attachment tend to become detached from the panels and deform, making it almost impossible to restore original attachment conditions. The affected panel is often also permanently damaged because the parts in which the screws or bolts are inserted break. This disadvantage makes it necessary for a building or a part of it to be demolished.

The object of the invention is to overcome the abovementioned disadvantages by providing a connection joint for wood panels which is stronger and more effective.

Another object of the invention is to provide a connection joint which does not have to be replaced in situations of even high intensity seismic events.

A further object of the invention is to provide a connection of the abovementioned type which can be manufactured industrially at low cost.

This and other objects will be accomplished through the connection, structure and method as claimed in the appended claims.

Disclosure of the Invention

The connection joint according to the invention may be advantageously used to connect wood panels arranged either vertically (wall panels) or horizontally (floor panels) to form the walls and floors of buildings. The joint comprises a plurality of ferrules, preferably made of steel. The ferrules are threaded internally and can be permanently engaged in corresponding holes provided in the sides of the wood panels. The ferrules are preferably engaged in the holes by bonding. Bonding may be brought about using a suitable adhesive of the hardening type. The holes are made in the panels along axes substantially parallel to the plane of the panels. Preferably the panels are provided with chamfered corners, so as to define a portion of the panel side perpendicular to the plane of the panel and chamfered with respect to the adjacent sides of the panel. The chamfer is preferably of 45°. The holes are made in the surface of the chamfered portion and there are preferably at least two. The connection also comprises a plurality of securing brackets. The securing brackets are provided with holes or slots for the passage of bolts which can be engaged in the ferrules so as to attach the brackets to the panels. The connection also comprises a node provided with at least a pair of plates. The plates are provided with holes or slots for the passage of attachment elements. Through the attachment elements the attachment brackets are firmly attached to a corresponding plate of the node. The attachment elements are preferably nuts and bolts. Advantageously, according to the invention, the joint comprises a cylindrical sleeve to guide a rod connecting joints together within it. The rod is preferably threaded and is locked with respect to the connection by means of nuts screwed onto the rod and tightened against the end of the guide sleeve. The rod connects at least two joints together or at least one joint and the structure of the building, for example the concrete foundation of a building. According to the invention the plates are attached to the sleeve along the respective generatrices of the sleeve. The plates vary in number according to the type of joint. In addition to this the plates are orientated around the sleeve at an angle that is selected according to the type of joint. For example joints may be provided to join adjacent panels lying in the same plane. In this case the plates will be positioned at 180° with respect to each other. Alternatively joints may be provided to join adjacent panels lying in perpendicular planes. In this case the plates will be arranged at 90° with respect to each other.

In accordance with a preferred embodiment of the invention, the ferrules will comprise a cylindrical metal body, preferably of steel, provided with a threaded axial hole that is open at at least one of its opposite ends. The ferrules will also preferably comprise an outer surface provided with longitudinal or transverse radial projections or a combination thereof or a thread to improve engagement of the ferrule into the hole provided in the panel by means of a hardening adhesive material.

Advantageously, according to the invention, the plates of the node comprise slots for the passage of attachment means. The slots advantageously allow the joint to adjust to spatial changes in the panels due to seismic movements. In addition to this the slots allow means of attachment deformed by movement induced by a seismic event to be replaced by other new straight ones. Not the last advantage of the slots is that they allow the joints to be assembled without excessive effort in centering and calculating the positions of panels and attachment brackets.

The plates are attached to the sleeve by welding. The sleeve and the plates therefore constitute a one-piece node.

The rods can be attached to corresponding rods, for example by means of threaded sleeves. In this way rods of the desired length suitable for use in different fields of application can be produced.

Advantageously the joint according to the invention makes it possible to achieve connecting structures capable of holding together a plurality of wooden panels of walls and floors of buildings.

Brief Description of the Figures

Some preferred embodiments of the invention will be provided by way of a non-limiting example with reference to the appended drawings in which: Figure 1A is a perspective view of a joint according to a first embodiment of the invention;

Figure IB is an exploded view of a detail of the joint in Figure 1 A;

Figure 2 is a perspective view of a joint according to a second embodiment of the invention;

Figure 3 is a perspective view of a joint according to a third embodiment of the invention;

Figure 4 is a perspective view of a building incorporating a structure of joints according to the invention;

- Figure 5 is a perspective view of the foundation of a building in accordance with a variant of the building incorporating a structure of joints according to the invention;

Figure 6 is a perspective view of the foundation of a building and a corresponding construction block according to a variant of the building which incorporates a structure of joints according to the invention (framed portions A and B are illustrated transparently);

Figure 6a is a detail of framed portion A in Figure 6;

Figure 6b is a detail shown transparently of framed portion B in Figure 6;

Figure 7 is a perspective view of the foundation, a construction block and a floor of a building according to a variant of a building incorporating a structure of joints according to the invention (framed portion C is seen transparently);

Figure 7 a is a detail of framed portion C in Figure 7;

Figure 8 is a perspective view of the foundation, a first construction block, a floor and a second construction block of a building according to a variant of a building incorporating a structure of joints according to the invention;

- Figure 9 is a perspective view of layers in cross-section of a wall panel of a building incorporating a structure of joints according to the invention.

In all the figures the same numerical reference numbers are used to identify identical or functionally equivalent components.

Description of a Preferred Embodiment

With reference to Figure 1A, this illustrates a first embodiment of the connection joint according to the invention. The joint is indicated as a whole by reference 11. In the embodiment illustrated joint 11 is configured to attach together four panels P, preferably four wall panels PI, P2, P3, P4. Wall panels PI and P2 lie in a first plane and wall panels P3, P4 lie in a second plane. The two planes are at right angles to each other.

With reference to Figure IB, connection joint 11 comprises a plurality of ferrules 13. The ferrules are threaded internally and can be permanently engaged in corresponding holes 15 provided in the sides of wooden wall panels P. Ferrules 13 are preferably secured in holes 15 by adhesive bonding using a hardening adhesive. The adhesive is injected into holes 15 before ferrules 13 are inserted. Ferrules 13 are then inserted into holes 15 and the adhesive is hardened. Holes 15 are made in wall panels P along axes substantially parallel to the plane of the panel. Preferably wall panels P are provided with chamfered corners, to define a side portion 17 of wall panel P that is perpendicular to the plane of the panel and chamfered with respect to the adjacent sides. In the example illustrated the chamfer is of 45°. Holes 15 are made in the chamfered surface of portion 17 and are preferably at least two in number.

With reference again to Figure 1A, joint 11 also comprises a plurality of fastening brackets 19. Fastening brackets 19 are provided with holes or slots 21a for the passage of bolts 23 that are adapted to be engaged in ferrules 13. Brackets 19 are attached to panels P by means of bolts 23 which are screwed right down into threaded holes 25 of ferrules 13. Joint 11 also comprises a node 27 equipped with at least one pair of plates 29. Plates 29 are provided with holes or slots 31 for the passage of fastening elements 33. Fastening elements 33 are provided to fix brackets 19 to plates 29 of node 27. Fastening elements 33 preferably comprise corresponding threaded pins 33a which are locked against brackets 19 and plates 29 by means of nuts 33b. In this way brackets 19 are firmly secured to a corresponding plate 29 of node 27. Brackets 19 comprise a first portion 19a provided with holes 21a for attachment to panel P and a second portion 19b provided with a slot 21b for the passage of threaded pins 33a. In the embodiment illustrated portions 19a and 19b are perpendicular to each other. In other embodiments said portions 19a, 19b may adopt other configurations suitable for the specific application. Brackets 19 may also be double brackets and comprise pairs of portions 19b that are parallel and at a distance from each other to house a plate 29 between them.

According to the invention, joint 11 comprises a cylindrical sleeve 35. Sleeve 35 preferably comprises a cylindrical steel tube. Sleeve 35 is intended to guide an interconnecting rod 37 for joints 11. Rod 37 is threaded and is locked against joint 11 by means of nuts 39 screwed onto rod 37 and locked against the opposite ends of guide sleeve 35. Rod 37 connects together at least two joints 11 or at least one joint 11 and the structure, for example concrete foundation 81, of a building 100. According to the invention plates 29 are attached to sleeve 35 along their respective generatrices. Plates 29 vary in number depending upon the nature of joint 11. An angle of 90° is provided between plates 29 in the embodiment illustrated, pairs of panels PI, P2 and P3, P4 lying in planes which are perpendicular to each other.

With reference to Figure 2, this illustrates a second embodiment of the invention in which node 11 is provided with three plates 29 arranged at 90° around guide sleeve 35. This arrangement allows six panels P, of which only three are illustrated, to be attached together.

With reference to Figure 3, this illustrates a third embodiment of the invention in which connection joint 11 is provided with six plates 29 arranged radially at 60° around guide sleeve 35. This arrangement allows twelve panels P, of which only six have been illustrated, to be attached together.

According to a further embodiment of the invention, it is also possible to provide for joints 11 to be located horizontally instead of vertically, so as to connect floor panels S instead of wall panels P.

According to a preferred embodiment, wall panels P are of rectangular or square shape and comprise, with reference to a vertical position of such panels as illustrated in Figures 6-8, lower sides 51, upper sides 52 and lateral sides 53; the chamfered corners previously described are therefore located between lower side 51 or upper side 52 and lateral sides 53.

According to a variant embodiment of wall panels P illustrated in Figures from 6 to 7a, lower holes 61 and upper holes 62 are provided in lower side 51 and upper side 52 respectively. These lower holes 61 and upper holes 62 are made along axes substantially parallel to the plane of the panel. With particular reference to Figure 6a, in wall panels P an adhesive bonding hole 64 and a check hole 65 made in face F of wall panels P are also provided for each of lower holes 61. Adhesive bonding hole 64 and check hole 65 communicate with corresponding lower hole 61. In particular, adhesive bonding hole 64 communicates with a zone of the lower hole which is distal with respect to lower side 51 in which the lower hole is made, while check hole 65 communicates with a zone of the lower hole that is close to that lower side 51.

Again with reference to the Figures from 6 to 7a, lower holes 61 and upper holes 62 are able to house corresponding pegs 70. The diameters and length of lower holes 61 and pegs 70 are selected so that a space remains between the holes and the pegs to house a sufficient but not excessive quantity of adhesive. In addition to this the length of pegs 70, which is longer than the length of corresponding lower holes 61, is chosen so that these can also engage in the holes of one or more contiguous elements (such as holes 81 in foundation 80 or holes 82 in floor panels S and upper holes 62 in wall panels P in a successive floor of building 100) in addition to corresponding lower holes 61, as will be explained below in the description. Pegs 70 are adhesive bonded into corresponding holes, preferably by means of bonding using a hardening adhesive. The adhesive is injected into the holes after the corresponding peg has been inserted, through corresponding adhesive bonding hole 64 and ends when the adhesive flows out of corresponding check hole 65. Preferably, a holding ferrule 66, which is threaded internally or made of resilient material, is provided in a zone of the lower holes between lower side 51 and check hole 65. Holding ferrule 66 makes it possible to hold peg 70 in position in corresponding lower hole 61 before it is adhesively bonded in the manner previously described. If holding ferrule 66 is threaded internally, suitably threaded pegs are provided to engage with the ferrule, while if holding ferrule 66 is of resilient material, this has an internal diameter such as to hold peg 70 in position through an interference fit.

Still according to the variant embodiment of wall panels P, lateral holes 63, made along axes substantially parallel to the plane of wall panel P, are made in sides 53. Corresponding lateral ferrules 67 are engaged in lateral holes 63, preferably in a manner similar to that described for ferrules 13 of joint 11, engaged in holes 15 of wall panels P. Attachment box-like elements 71 comprising lateral faces 72 (parallel to lateral sides 53 of wall panels P) and lower and upper faces 76 are provided between lateral sides 53 of wall panels P. Lateral faces 72 are provided with slots or holes 73 which allow attachment box-like elements 71 to be attached to wall panels P through the use of attachment elements, for example bolts 74, which engage lateral ferrules 67 in lateral sides 53 of wall panels P. Upper and lower faces 76 are also provided with holes 77 which allow rod 37 to pass within them. Preferably attachment box-like elements 71 are formed in two parts - a first part comprising upper and lower faces 76 and all lateral faces 72 of the box-like element but for at least one of such lateral faces, and a second part comprising the said at least one lateral face not included in the first part. The first part of the box-like element therefore provides a working area, provided thanks to the lack of the second part, which makes it possible to easily insert bolts 74 to attach to wall panels P. The two parts of the box-like elements therefore comprise lateral faces having free lateral edges, i.e. lateral edges that are not contiguous with a subsequent lateral face 72. An attachment boxlike element 71 is therefore produced by joining its first and second parts, welding the free edges of the first part to the corresponding free edges of the second part. Suitable slots 54 made in edge 55 of wall panels P between face F of the panel and lateral side 53 of the panel, along the free lateral edges of the first and/or second part of attachment box-like elements 71 , are also provided in order to make welding possible.

Attachment box-like elements 71 may have different shapes depending upon the number and orientation of the wall panels P between which they are located. For example rectangular or cubic attachment box-like elements are suitable for use with the second and third embodiments of joint 11 illustrated in Figures la and 2, while box-like elements in the form of a hexagonal prism are suitable for the third embodiment of joint 11 illustrated in Figure 3.

Further variants of wall panels P comprising only the characteristics described above relating to the upper and lower sides or only the characteristics described above relating to the lateral sides are also provided.

The connection joint according to the invention makes it possible to construct buildings 100 comprising at least one floor of a building, in which each floor of the building has wooden wall panels P and floor panels S. The method for constructing building 100 comprises:

- a first step in which construction blocks comprising at least two contiguous wall panels P on one floor of the building are constructed (Figures 1-3, 6, 6a and 6b);

- a second step in which the construction blocks are erected on foundation 80 of the building to form a first floor of the building (Figure 6), and

- a third step in which floors and construction blocks are erected to form successive floors of the building above the first (Figures 7, 7a and 8).

With reference to Figures 1-3, wooden wall panels P capable of defining the walls of building 100 are provided in the first stage. These wall panels P may be of a known type, for example of the X-LAM (cross laminated timber) laminated type, of laminated fir wood, microlaminated fir wood, microlaminated beech wood or other types. Preferably, in case of high tensile and shear stresses, the laminated type panel comprises a central layer of microlaminated hardwood, for example beech or birch wood, thanks to which it is possible to obtain tensile strengths of 60% higher than if a central layer of fir wood is used. With reference to Figure 9, one embodiment of wall panel P of the laminated type according to the invention comprises two outer layers 56 of vertical fir lamellae, two intermediate layers 57 of horizontal fir lamellae and a central microlaminated layer 58 of beech wood.

In order to fit connecting joint 11, wall panels P must be provided with holes 15 capable of housing internally threaded ferrules 13. The first step of the method therefore provides a step in which wall panels P are provided with holes 15 along axes substantially parallel to the plane of wall panel P. The depth and diameter of these holes 15 vary according to applications. Adhesive is preferably injected into holes 15 and then ferrules 13 are inserted until the adhesive, when present, is forced out of holes 15. In this embodiment which provides for an adhesive the diameters and depth of holes 15 are selected such that an intermediate space remains between ferrules 13 and holes 15 to house a sufficient but not excessive quantity of adhesive. At the end of this step ferrules 13 are permanently engaged in the sides of wall panels P. The first step of the method according to the invention therefore provides that attachment brackets 19 are fixed to wall panels P by means of bolts which engage the threaded holes in ferrules 13. Brackets 19 comprise a portion 19a provided with holes 21a for the passage of bolts 23 which engage ferrules 13 and a portion 19b provided with holes or slots 21b to secure bracket 19 to node 27 of joint 11. Brackets 19 are stably secured to the plates 29 of node 27 through fastening elements 33.

Advantageously slots 21b provided in brackets 19 and slots 31 provided in plates 19 also make it possible to mount node 27 with a plurality of wall panels P without requiring complicated centering operations. Advantageously, when wall panels P of the X-LAM laminated type are used with a central microlaminated layer of hardwood the positioning of ferrules 13 at this central layer of the panel imparts greater tensile strength to building 100 as a whole and at the same time makes it possible to use a softer wood for the outer layers of the panel, reducing costs.

An interconnecting rod 37 is inserted into guide sleeve 35 of node 27. Rod 37 is preferably threaded at least at the opposite ends so that further rods 37 can be connected by means of threaded nuts or sleeves. The said threaded nuts or sleeves may correspond to nuts 39 used to lock connection joints 11 along rod 37. Through this arrangement the length of rod 37 can be extended in such a way that a plurality of connection joints 11 which are in line with each other in the structure of building 100 can be interconnected.

According to a preferred embodiment of the method according to the invention wall panels P are of a rectangular or square shape. In addition to this, preferably, wall panels P are provided with chamfered corners defining corresponding portions 17 for the insertion of ferrules 13.

With reference to Figures 6, 6a and 6b, according to a variant of the method of constructing building 100, the first step of the method also comprises the steps of:

- providing lower holes 61 in the lower sides 51 of wall panels P; - providing an adhesive bonding hole 64 and check hole 65 for each of lower holes 61;

- providing box-like attachment elements 71 located between the lateral sides 53 of contiguous wall panels P and attached thereto.

This step of providing box-like attachment elements 71 located between lateral sides 53 of contiguous wall panels P and attached thereto preferably comprises the steps of:

- providing lateral holes 63 in lateral sides 53 of wall panels P;

- securing lateral ferrules 67 in lateral holes 63, preferably through the injection of an adhesive;

- providing attachment box-like elements 71 constructed in at least two parts, the first part comprising upper and lower faces 76 and all lateral faces 72 of the box-like element but for at least one of such lateral faces, and a second part comprising the said at least one lateral face not included in the first part, in such a way that the first part provides a suitable working opening obtained through the absence of the second part;

- attaching the first part of box-like elements 71 to corresponding lateral sides 63 of wall panels P using bolts 74 which engage lateral ferrules 67, advantageously working from the suitably provided working opening;

- attaching the second part of box-like elements 71 to corresponding lateral side 53 (or corresponding lateral sides where the second part comprises more than one lateral face 72) in a similar manner to that specified for the first part;

- providing suitable ferrules 54 located in edges 55 of wall panels P between face F of the panel and lateral side 53 of the panel, at free lateral edges of the first and/or second part of box-like attachment elements 71 ;

- joining the first and second parts of attachment box-like elements 71, previously attached to corresponding wall panels P, by welding between the free lateral edges of the first and second part, advantageously using suitably provided slots 54.

In a second step of the method for the construction of building 100, construction blocks constructed in accordance with the first step of the method are erected on foundation 80 of the building.

The second step of the method comprises the steps of:

- positioning the construction blocks on foundation 80, suitably levelled in the known way;

- attaching, preferably, rods 37 to foundation 80 of building 100;

- joining, preferably, contiguous construction blocks by means of joints 11. With reference to Figures 6, 6a and 6b, according to the variant of the method for the construction of building 100 the second step of the method also comprises the steps of:

- providing construction blocks 90 constructed in accordance with the variant of the first step of the method, or construction blocks 90 comprising wall panels P in which lower holes 61 made in the lower sides 51 of wall panels P, an adhesive bonding hole 64 and a check hole 65 for each of these lower holes 61 are provided, and which comprise attachment box-like elements 71 ;

- providing pegs 70, inserting them into the corresponding lower holes 61 of wall panels P of construction block 90 and holding them in position;

- providing holes 81 in foundation 80, at pegs 70 and therefore lower holes 61 of wall panels P in construction block 90;

- positioning construction block 90 on foundation 80 in such a way that pegs 70 are inserted into holes 81 of foundation 80;

- pouring self-levelling non-shrinking cement into holes 81 so that pegs 70 remain of one piece with foundation 80;

- adhesively bonding pegs 70 in the lower holes 61 through the injection of a hardening adhesive into adhesive bonding hole 64, which ends when the adhesive emerges from check hole 65;

- providing that rods 37 pass through holes 77 provided in the upper and lower faces 76 of box-like elements 71 ;

- joining, preferably, wall panels P of contiguous construction blocks 90 by means of attachment box-like elements 71.

In the third step of the method for the construction of building 100 construction blocks of the building are erected to construct floors of the building above the first.

This third step of the method comprises the steps of:

- providing floor panels S ;

- creating a floor by positioning floor panels S on upper sides 52 of wall panels P of the construction blocks of a lower floor of the building;

- providing construction blocks constructed in accordance with the first step of the method;

- positioning the construction blocks constructed in accordance with the first step of the method on the floor; - attaching joints 11 of a construction block of an underlying floor of the building to wall panels P of the corresponding construction block previously positioned on the floor;

- attaching rod 37 to joint 11 of the construction block previously positioned on the floor by means of bolts or threaded sleeves, in the same way as described in the first step of the construction method;

- joining, preferably, contiguous construction blocks of the current floor of the building by means of joints 11.

With reference to Figures 7, 7a and 8, according to the variant of the method of construction of building 100 the third step of the method also comprises the steps of:

- providing floor holes 82 in floor panels S;

- providing construction blocks 90 constructed in accordance with the variant of the first step of the method, or construction blocks 90 comprising wall panels P in which lower holes 61 made in the lower sides 51 of wall panels P, an adhesive bonding hole 64 and a check hole 65 for each of such lower holes 61 are provided, and which comprise attachment box-like elements 71;

- making upper holes 62 in wall panels P of a construction block 90 of an underlying floor of the building, at floor holes 82 in the floor panels S previously positioned on that construction block 90 of the underlying floor of the building;

- providing pegs 70 and inserting them into the holes of floor 82 of floor panels S and then in the corresponding upper holes 62 previously made in wall panels P of construction block 90 of the underlying floor of the building;

- positioning construction blocks 90 previously provided on the floor in such a way that pegs 70 are inserted into lower holes 61 of wall panels P of such construction blocks 90 of the current floor;

- adhesively bonding pegs 70 in lower holes 61 through the injection of a hardening adhesive into adhesive bonding hole 64, which ends when the adhesive emerges from check hole 65;

- providing that rods 37 pass through holes 77 provided in the upper and lower faces 76 of box-like elements 71 ;

- joining, preferably, wall panels P in contiguous construction blocks 90 by means of attachment box-like elements 71.

With reference to Figure 4, this illustrates schematically a building incorporating a structure obtained using connection joints 11 constructed according to the invention. In accordance with a particular embodiment of the invention, panels P provided with chamfered corners are associated together by means of joints 11 in such a way that they are spaced apart and define a vertical channel 41 for the passage of rod 37. Advantageously, according to the invention, this channel 41 is closed off on the outside by means of a suitable sheath or cover 43. After sheath 43 has been fitted, a hardening material, for example concrete, may be poured into channel 41. As result of this arrangement the structure of the building therefore becomes extremely solid and capable of absorbing the forces due to any seismic events. In addition to this, advantageously, in accordance with the invention the forces due to seismic events are discharged in the connections between brackets 19 and plates 29 of node 27 without jeopardizing the attachment to panels P through ferrules 13. This behaviour of the structure of the building is particularly advantageous because the wood panels do not generally undergo damage and deformation and the building can be restored by working on the metal structure of the nodes and rods.

The invention as described and illustrated is susceptible of many variants and modifications falling within the same inventive principle.