JOINING DEVICE FOR WOODEN STRUCTURES

Abstract

Joining device for wooden structures. The invention relates to a joining device for wooden structures comprising two elongated pieces that can be coupled and decoupled axially. Each piece has: a cylindrical intermediate shaft, a head at one end of the cylindrical intermediate shaft, and a stem extending from the other end of the cylindrical intermediate shaft, the cross-section of the stem being smaller than that of the cylindrical intermediate shaft. The two pieces are configured such that, when axially coupled, they can adopt two relative angular positions: a locking position in which expansions of the stems overlap, thus anchoring the two pieces axially to each other, and a release position in which relative axial displacement between the two pieces is permitted in opposite directions.The device of the invention reduces the size of the perforation made in the elements -boards or bars- to be joined, thus preventing the weakening of the joint.

Description

JOINING DEVICE FOR WOODEN STRUCTURES OBJECT OF THE INVENTION The invention relates to a joining device for wooden structures. This device consists of three parts; two of which, complementary to each other, prevent the elements—boards or bars—they join from separating from each other—perpendicular to their working plane—thus preventing the joint from coming undone. These parts, passing—in most cases—through the bars they are intended to join, are inserted at opposite ends of the set of bars to be secured. A rotation is then performed to prevent the parts from moving in the opposite direction to the one in which they were inserted. A third part is inserted into one of the two mentioned above to prevent, if necessary, reversing the rotation that secures the joint. The invention is preferably applicable to forming structures made solely of wood. STATE OF THE ART There are known joining devices for wooden structures whose operating system is similar to that of the device that is the object of the invention, which are either metallic -like bolts-, or made of wood, but they require a larger perforation in the elements that they pass through and fix to guarantee the effectiveness of the joint, which weakens the resistance of said joint by the reduction of the section of the elements that it joins. An example of this latter type of device is shown in claim 2 of Spanish patent ES-2,944,807 A1, which describes a wooden key that ensures its effectiveness by means of two flexible linear elements located at both of its ends, which, in order to pass through the set of bars that are to be "embraced", are inserted in a "retracted" position and, once inserted, return to their initial "extended" position, collecting with separate tabs the set of elements to be joined. DESCRIPTION OF THE INVENTION The device consists primarily of two complementary, elongated pieces that hold the elements—boards or bars that make up the wooden structures—together perpendicular to their working plane, preventing the joint from coming undone. These pieces pass through the elements they are intended to join and are inserted at opposite ends of the assembly to be secured. A subsequent rotation prevents the pieces from moving in the opposite direction. A third piece is inserted into one of the two previously mentioned pieces to, if necessary, prevent reversing the rotational movement that secures the joint. More specifically, the invention relates to a joining device for wooden structures characterized by comprising two elongated pieces that can be coupled and decoupled from each other in an axial direction within a cylindrical perforation made in the wooden elements to be joined. Each of the pieces comprises: a cylindrical intermediate trunk, a head at one end of the cylindrical intermediate trunk, a stem emerging from the other end of the cylindrical intermediate trunk - the cross-section of the entire stem being smaller than that of the cylindrical intermediate trunk - and the stem having a widening at its free end. Preferably, the head is cylindrical and has a larger diameter than the diameter of the intermediate cylindrical trunk and the perforation through which the device joins the elements that make up the wooden structures. The two pieces are configured so that, when axially coupled, they can adopt two relative angular positions to each other, namely: a locking position in which the stem widenings overlap so that the two pieces are axially anchored to each other, and a release position in which the stem widenings do not overlap (they are misaligned) allowing relative axial displacement between both pieces in opposite directions. The stem of each part has a larger section and a smaller section. The larger section defines the widening and extends from the smaller section to the free end of the stem. The smaller section is located between the larger section and the intermediate cylindrical trunk of the part, and the axial length of the larger section of the stem of one part is equal to the axial length of the smaller section of the stem of the other part. The cross-section of the larger section segment and the smaller section segment of the stem of each piece is constant throughout its length. In a preferred embodiment of the invention, the cross-section of the stem of one of the pieces is a 180° circular sector in the larger section section and a circular segment in the smaller section section of the stem, and the cross-section of the stem of the other piece is a 90° circular sector in the larger section section and a circular segment in the smaller section section of the stem. Preferably, the stems of the first and second piece are shaped so that the curved surface of each stem is a continuation of the curved surface of the intermediate cylindrical trunk. In a preferred embodiment of the invention, at least one of the parts has a straight through-hole through the head and the intermediate cylindrical shaft. The device further comprises a pin that can be inserted into said hole, the pin being longer than the hole, and the hole being arranged so that, in the locked position of the two parts, the pin inserted in the hole prevents relative rotation between the two parts, in order to prevent the two parts from becoming undesirably separated. Preferably, the three pieces are rigid and made entirely of wood or a plastic material suitable for their function. BRIEF DESCRIPTION OF THE FIGURES To complete the description and to provide a better understanding of the invention, a set of drawings is provided, which form an integral part of the description and illustrate embodiments of the invention. These drawings should not be interpreted as restricting the scope of the invention, but only as examples of how the invention can be carried out. The drawings comprise the following figures: Figure 1 shows, in Figures 1A and 1B, perspective views from different angles of the joining device, with the parts detached. The cylindrical tubular body represents the cylindrical perforation made in the elements to be joined, within which the two parts of the device are fitted. Figure 2 shows in figures 2A and 2B two perspective views from different angles of the joining device, with the parts in a first coupling phase. Figure 3 shows in figures 3A and 3B two perspective views from different angles of the joining device, with the pieces attached. Figure 4 shows in Figure 4A a plan view of the first piece; Figure 4B a plan view of the second piece, and Figure 4C is a representation of the coupling between both pieces when both widenings are superimposed. PREFERRED EMBODIMENT OF THE INVENTION Figures 1A and 1B show a preferred embodiment of a joining device (1) for wooden structures, comprising a first piece (2) and a second piece (3) that can be coupled and decoupled from each other in the axial direction within a cylindrical perforation (4) made in the wooden pieces to be joined. The first piece (2) is a single body, consisting of a cylindrical intermediate trunk (2a), a head (2b) at one end of the cylindrical intermediate trunk (2a) and a stem (2c) emerging from the other end of the cylindrical intermediate trunk (2a), the shape of the cross-section of the stem being approximately corresponding to a circular sector of the cylindrical intermediate trunk (2a), and the stem having a widening (2d) at its free end. The head (2b) is preferably cylindrical and has a larger diameter than the bore (4). The intermediate cylindrical stem (2a) has a smaller diameter than the bore (4), the one necessary for them to fit together. The outer perimeter surface of the stem (2c) and its enlargement (2d) are a continuation of part of the curved surface of the intermediate cylindrical stem (2a), each with a different surface area. Similarly, the second piece (3) is a single body, consisting of a cylindrical intermediate trunk (3a), a head (3b) at one end of the cylindrical intermediate trunk (3a), and a stem (3c) emerging from the other end of the cylindrical intermediate trunk (3a), the shape of the cross-section of the stem being approximately corresponding to a circular segment of the cylindrical intermediate trunk (3a), and the stem having a widening (3d) at its free end. The head (3b) is preferably cylindrical and has a larger diameter than the bore (4). The intermediate cylindrical stem (3a) has a smaller diameter than the bore (4), the one necessary for them to fit together. The outer perimeter surface of the stem (3c) and its enlargement (3d) are a continuation of part of the curved surface of the intermediate cylindrical stem (3a), each with a different surface area. The two pieces (2, 3) are configured in a complementary shape so that, when axially coupled, they can adopt two relative angular positions: a locking position shown in Figures 3A and 3B, in which the swellings (2d, 3d) of the stems are superimposed so that the two pieces (2, 3) are axially anchored to each other, and a release position shown in Figures 1A, 2A and 1B, 2B in which relative axial displacement between the two pieces (2, 3) is permitted in opposite directions. The stem (2c) of the first piece (2) has a larger section section and a smaller section section. The larger section section defines the widening (2d) and extends from the smaller section section to the free end of the stem, and the smaller section section is located between the larger section section and the intermediate cylindrical trunk (2a) of the piece (2). Similarly, the stem (3c) of the second part (3) has a larger section section and a smaller section section. The larger section section defines the widening (3d) and extends from the smaller section section to the free end of the stem, and the smaller section section is located between the larger section section and the intermediate cylindrical trunk (3a) of part (3). The axial length of the larger section segment (2d, 3d) of the stem (2c, 3c) of one piece (2, 3) is equal to the axial length of the smaller section segment of the stem (2c, 3c) of the other piece (2, 3). Furthermore, the cross-section of the larger section segment (2d, 3d) and the smaller section segment of the stem (2c, 3c) of each piece (2, 3) is constant throughout its length. In this preferred embodiment, the cross-section of the larger section section (3d) of the stem (3c) of the second piece (3) is a 180° circular sector, while the cross-section of the smaller section section of the stem (3c), having to be recessed inwards with respect to the cross-section of the larger section section (3d) in order to anchor the cross-section of the larger section section (2d) of the stem (2c) of the first piece (2), is a circular segment, and the cross-section of the larger section section (2d) of the stem (2c) of the first piece (2) is in the shape of a 90° circular sector, while the cross-section of the smaller section section of the stem (2c), having to be recessed inwards with respect to the cross-section of the larger section section (2d) in order to anchor the cross-section of the larger section section (3d) of the stem (3c) of the second piece (3), is a circular segment. Preferably, in the embodiment shown in the figures, the second part (3) has a straight through-hole (5) through the head (3b) and the intermediate cylindrical section (3a). The device (1) further comprises a third part, a pin (6), insertable into said hole (5) and longer than the hole (5). The hole (5) is positioned so that, in the locked position (Figures 3A and 3B) between the two parts (2, 3), the pin (6) can be inserted into the hole (5), protruding sufficiently from the inner base of the cylindrical portion (3a) of the second part (3), as shown in Figure 3B, to prevent relative rotation between the two parts (2, 3), thus ensuring that the joint between them does not come apart. The three pieces (2, 3, 6) are rigid and made entirely of wood or a plastic material suitable for their function. For coupling between parts (2, 3), both are inserted axially into the cylindrical bore (4) as shown in Figures 1A and 1B, i.e., in a position where the free ends of the stems (2d, 3d) of both parts (2, 3) are not aligned. This allows both parts (2, 3) to be inserted into the bore (4) as far as they will go, until the free end of each stem contacts the base of the intermediate cylindrical section (2a, 3a) of the other part, as shown in Figures 2A and 2B. In this position, one of the parts is rotated relative to the other until the free ends of the stems (2d, 3d) overlap, thus locking both parts (2, 3) together. Finally, the pin (6) is inserted into the hole (5) to prevent relative rotation between the parts.

Claims

1. - Joining device (1) for wooden structures characterized in that it comprises: two elongated pieces (2, 3) that can be coupled and decoupled from each other in the axial direction, where each of the pieces (2, 3) comprises: an intermediate cylindrical trunk (2a, 3a), which has a diameter adjusted to the perforation (4) through which the device (1) joins the elements that make up the wooden structures.a head (2b, 3b) at one end of the intermediate cylindrical trunk (2a, 3a), the head (2b, 3b) being wider than the intermediate cylindrical trunk (2a, 3a) and the aforementioned perforation (4), a stem (2c, 3c) emerging from the other end of the intermediate cylindrical trunk (2a, 3a), the cross-section of the entire stem (2c, 3c) being smaller than that of the intermediate cylindrical trunk (2a, 3a), and the stem (2c, 3c) having a widening (2d, 3d) at its free end, and where the two pieces (2, 3) are configured so that, when axially coupled, they can adopt two relative angular positions: a locking position in which the widenings (2d, 3d) of the stems (2c, 3c) are superimposed that the two pieces (2, 3) are axially anchored to each other, and a release position in which relative axial displacement between both pieces (2, 3) is permitted in both directions. 2.- Joining device for wooden structures, according to claim 1, wherein the stem (2c, 3c) of each piece has a larger section section and a smaller section section, the larger section section defines the widening (2d, 3d) and extends from the smaller section section to the free end of the stem, and the smaller section section is comprised between the larger section section and the intermediate cylindrical trunk (2a, 3a) of the piece, and wherein the axial length of the larger section section (2d, 3d) of the stem (2c, 3c) of one piece (2, 3) is equal to the axial length of the smaller section section of the stem (2c, 3c) of the other piece (2, 3).

3. A joining device for wooden structures, according to claim 2, wherein the cross-section of the larger section segment (2d, 3d) and that of the smaller section segment of the stem (2c, 3c) of each piece (2, 3) is constant along its entire length. 4.- A joining device for wooden structures, according to claim 3, wherein the cross-section of the stem (3c) of one of the pieces (3) is a 180° circular sector in the larger section (3d) and a circular segment in the smaller section, and wherein the cross-section of the stem (2c) of the other piece (2) is a 90° circular sector in the larger section (2d) and a circular segment in the smaller section.

5. A joining device for wooden structures, according to claim 4, in that the stems (2c, 3c) of the first and second pieces (2, 3) are shaped such that the curved surface of each stem (2c, 3c) and its widening (3c, 3d) are continuous with part of the curved surface of the intermediate cylindrical shaft (2a, 3a), each with a different surface area. 6.- Joining device for wooden structures, according to any of the preceding claims, wherein the head (2b, 3b) is preferably cylindrical and has a diameter greater than the diameter of the intermediate cylindrical trunk (2a, 3a) and the perforation (4) through which the device (1) joins the elements that make up the wooden structures. 7.- Joining device for wooden structures, according to any of the preceding claims, wherein at least one of the pieces (2, 3) has a straight through hole (5) through the head (2b, 3b) and the intermediate cylindrical trunk (2a, 3a), and wherein the device further comprises a third piece, a pin (6), insertable into said hole (5), the pin (6) being longer than the hole (5), and said hole (5) being arranged so that in the locked position of the two pieces (2, 3), the pin (6) inserted in the hole (5) prevents relative rotation between the two pieces (2, 3), thus ensuring that the joint between them does not come apart. 8.- Joining device for wooden structures, according to any of the preceding claims, wherein each of the pieces (2, 3, 6) are rigid and are made entirely of wood or of a plastic material suitable for their functionality.

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