IMPROVED FASTENING ELEMENT

Description

Technical Field

[0001] This presentation concerns a fastening element for equipment intended to be fixed to trees. Previous technique

[0002] Adventure course or treetop adventure structures are structures commonly built in nature, in trees, typically at a height.

[0003] One issue related to such structures concerns the attachment of the various components to the trees, in order to meet safety requirements without damaging the trees. It is clear that attachments that damage the trees would be in direct contradiction with the very principle of such structures, and would also compromise the overall robustness over time. Document EP0921252 A2 presents an example of a known attachment component.

[0004] The present presentation aims to propose a fastening system that at least partially addresses these issues. Description of the invention

[0005] To this end, the present description relates to a fastening element adapted to be partially inserted into a tree, as claimed in claim 1, and comprising a body extending along a longitudinal direction defined by a longitudinal axis, said body comprising successively, from a proximal end to a distal end along the longitudinal direction: a first threaded portion, adapted to be inserted into a tree trunk, a collar, a nut, a second threaded portion, in which the first threaded portion and the second threaded portion have maximum diameters D1 and D2 respectively with respect to the longitudinal axis, the collar has a cylindrical shape of revolution of diameter D3 with respect to the longitudinal axis, such that D3 > 1.3 D1, and D3 > 1.3 D2, and a length Lc with respect to the longitudinal direction between 30 mm and 90 mm, the nut has a cross-section with respect to a plane perpendicular to the longitudinal axis inscribed in a regular polygon, said regular polygon being inscribed in a circle of diameter D4, such that D4 < D3, and D4 > D2, said fastener being made in one piece.

[0006] As an example, diameters D1 and D3 are between 15 and 40 mm.

[0007] According to one example, the fastening element includes a first transition portion interposed between the first threaded portion and the collar, the first transition portion forming a fillet.

[0008] According to one example, the fastening element includes a second transition portion interposed between the nut and the second threaded portion, the second transition portion forming a fillet.

[0009] According to an example, the diameters D3 and D4 are such that D4 < 0.8 D3.

[0010] According to one example, the first threaded portion has a wood-type thread, with a thread root of 16, 17 or 20 mm, a thread top of 22, 24 or 27 mm, and a pitch of 6, 8 or 9 mm.

[0011] According to one example, the second threaded portion has an M22-ISO type thread.

[0012] According to one example, the fixing element is formed of steel or stainless steel, for example 303 / 304 stainless steel or galvanized steel, or s355 steel with a tensile breaking strength (Rm) greater than or equal to 500 MPa.

[0013] According to one example, the collar includes a groove extending around its periphery, the groove extending at a distance from a proximal end of the collar of between 0.2 and 0.5 Lc, where Lc is the length of the collar measured along the longitudinal axis (XX).

[0014] According to one example, the nut has a cross-section along a plane perpendicular to the longitudinal axis, defining a regular polygon whose vertices have been truncated. Brief description of the drawings

[0015] The invention and its advantages will be better understood upon reading the detailed description below of various embodiments of the invention given by way of non-limiting examples. [Fig. 1 ] There figure 1 presents an example of a fastening element according to one aspect of the present invention. Fig. 2 ] There figure 2 presents another example of a fastening element, not claimed. Fig. 3 ] There figure 3 presents another example of a fastening element, not claimed.

[0016] Across all figures, common elements are identified by identical numerical references. Description of the implementation methods

[0017] There figure 1 presents an example of a fastening element 1 according to one aspect of the present invention.

[0018] The fixing element 1 has a body 10 extending along a longitudinal direction defined by a longitudinal axis XX. In the following description, elements extending axially will be understood as elements extending along the longitudinal axis XX, and elements extending radially will be understood as elements extending radially with respect to the longitudinal axis XX.

[0019] A proximal end 12 and a distal end 14 are arbitrarily defined for the body 10 along the longitudinal axis XX; these designations are purely arbitrary. The proximal and distal ends of the various elements will subsequently be defined with respect to these two ends of the body 10.

[0020] The fixing element 1 comprises successively, from its proximal end 12 to its distal end 14, a first threaded portion 20, a collar 30, a nut 40 and a second threaded portion 50.

[0021] Optionally, the fixing element 1 includes a first transition portion 23 interposed between the first threaded portion 20 and the collar 30.

[0022] Optionally, the fastening element 1 includes a second transition portion 45 interposed between the nut 40 and the second threaded portion 50.

[0023] The first threaded section 20 includes a thread adapted for insertion into a wood-like material, typically a tree trunk. The thread on the first threaded section typically has a maximum diameter of 27 mm, trapezoidal threads with a 60° angle, a thread crest of 1.5 mm, and a pitch of 8 mm. The first threaded section 20 typically has a wood-type thread, with a root diameter of 16, 17, or 20 mm, a thread crest of 22, 24, or 27 mm, and a pitch of 6, 8, or 9 mm.

[0024] The first threaded portion 20 has a maximum diameter D1 with respect to the longitudinal axis XX, this diameter typically corresponding to the diameter of a cylinder of revolution tangent to the vertices of the threads of the first threaded portion 20.

[0025] One end of the first threaded portion 20, forming the proximal end 12 of the body 10 of the fastening element 1, can typically form a point, so as to facilitate its penetration into a tree, or can be in the form of a truncated point.

[0026] The first threaded portion 20 typically has a length along the axial direction of between 90 mm and 160 mm, for example between 100 mm and 140 mm, or more precisely between 110 and 135 mm.

[0027] The collar 30 has a cylindrical shape of revolution with diameter D3 around the longitudinal axis XX. The collar 30 has a diameter D3 that is strictly greater than D1, such that D3 > 1.3 D1, or D3 > 1.5 D1. The diameter D3 is typically between 40 mm and 80 mm, or between 50 mm and 70 mm, or more precisely between 55 mm and 65 mm, or for example equal to 60 mm.

[0028] The collar 30 typically has a length Lc along the axial direction, typically between 30 mm and 90 mm, or for example between 40 mm and 80 mm, or between 50 mm and 70 mm, or for example between 55 mm and 65 mm, for example equal to 62 mm.

[0029] A groove 34 or channel is typically formed in the collar 30. The groove 34 typically has a depth measured along the radial direction of between 1 mm and 5 mm, and a length measured along the axial direction of between 1 mm and 5 mm.

[0030] Groove 34 has, in particular, a reference function for a user, as will be described later.

[0031] The groove 34 is typically formed at a distance from a proximal end of the collar 30 of between 0.2 and 0.5 Lc, or typically between 0.25 and 0.35 Lc.

[0032] The nut 40 typically has a cross-section along a plane perpendicular to the longitudinal axis XX defining a regular polygon, for example a regular hexagon, said regular polygon being typically inscribed in a circle of diameter D4, such that D4 < D3. The diameter D4 is typically between 30 mm and 50 mm, for example between 35 mm and 45 mm.

[0033] According to one example, the said regular polygon has truncated edges.

[0034] Nut 40 typically has a length L40 along the axial direction of between 10 mm and 30 mm, or between 15 mm and 25 mm, or for example between 20 mm and 25 mm.

[0035] The second threaded portion 50 has a maximum diameter D2 with respect to the longitudinal axis XX, this diameter typically corresponding to the diameter of a cylinder of revolution tangent to the vertices of the threads of the second threaded portion 50. The diameter D2 is such that D4 > D2, and such that D3 > 1.3 D2, or D3 > 1.5 D2.

[0036] The second threaded portion 50 typically has an M22-ISO type thread.

[0037] The second threaded portion 50 typically has a length L50 measured along the axial direction of between 60 mm and 100 mm, or between 60 mm and 80 mm.

[0038] The second threaded portion 50 typically has a distal end on which a chamfer is made, this distal end of the second threaded portion 50 forming the distal end 12 of the body 10 of the fixing element 4. The chamfer thus made typically has an angle of 30° with respect to the axial direction, and extends over a length between 2 mm and 4 mm, or for example equal to 3 mm along the axial direction.

[0039] As previously stated, the fixing element 1 optionally includes a first transition portion 23 interposed between the first threaded portion 20 and the collar 30. This first connecting portion forms a fillet, typically with a radius between 5 mm and 10 mm, from the diameter D1 of the first threaded portion 20.

[0040] Such a first transition portion 23 forming a fillet between the first threaded portion 20 and the collar 30 makes it possible to improve the mechanical strength of the fastening element 1, by avoiding the formation of crack initiations between these two regions having distinct diameters.

[0041] As previously stated, the fixing element 1 optionally includes a second transition portion 45 interposed between the nut 40 and the second threaded portion 50. This first connecting portion forms a fillet, typically with a radius between 5 mm and 10 mm, from the diameter D2 of the second threaded portion 50.

[0042] Such a second transition portion 45 forming a fillet between the nut 40 and the second threaded portion 50 makes it possible to improve the mechanical strength of the fastening element 1, by avoiding the formation of crack initiations between these two regions having distinct diameters.

[0043] Optionally, a fillet can also be formed between the collar 30 and the nut 40, typically with a radius between 1 mm and 3 mm.

[0044] We now describe the functions and use of the fixing element 1 as presented.

[0045] The fixing element 1 is suitable for insertion into a shaft, for example for the support of a structure or equipment.

[0046] The first threaded portion 20 is inserted into a shaft by screwing, in particular by means of a tool engaging the nut 40.

[0047] The fastening element 1 is thus inserted into the shaft until the collar 30 is at least partially inserted into the shaft. The collar 30 is typically inserted into the shaft up to the groove 34, which may serve as a visual reference point for the user.

[0048] To facilitate insertion, a pre-drilling is typically carried out beforehand in the trunk of the tree, using a drill bit with two distinct sections; a first section having a diameter strictly less than D1 and forming a pre-drilling for the first threaded portion 20, and a second section having a diameter equal to D3, to form a housing receiving the collar 30.

[0049] Thus, the nut 40, the second threaded portion 50, and, where applicable, a portion of the collar 30 remain outside the tree trunk. Keeping a portion of the collar 30 outside the tree trunk allows for tree growth, and therefore an increase in its diameter, which gradually covers the rest of the collar 30, while keeping the nut 40 accessible to allow for the possible removal of the fastener 1.

[0050] It is also understood that the positioning of the nut 40 and, where applicable, of the second transition portion 45, ensures a spacing between the tree trunk into which the fixing element 1 is inserted, and a structure or equipment associated with the fixing element 1, thus allowing space for the growth of the tree.

[0051] The second threaded portion 50 is thus used to associate a structure or equipment with the fixing element 1, and therefore to fix this structure or equipment to the shaft.

[0052] During use, the fastening element 1 will ensure improved support for the equipment or structure to which it is attached. The first threaded portion 20 inserted into the shaft will provide pull-out resistance. The collar 30, which is at least partially inserted into the shaft, will ensure good shear strength and prevent the hole formed in the shaft from enlarging under shear stress.

[0053] The proposed fixing element 1 thus not only improves the mechanical strength of the fixing made in a tree, but also prevents possible damage to the tree under the effect of a shear force applied to the fixing element 1, this effect being canceled here by the presence of the collar 30.

[0054] The proposed fixing element 1 allows for a robust fixing without the need for straps or other elements surrounding the tree trunk, which would degrade it over time.

[0055] Since the fastening element is a one-piece mechanical component, it also requires no maintenance operations, and is therefore particularly advantageous in terms of operation.

[0056] The fixing element 1 is typically formed of steel or stainless steel, for example 303 / 304 stainless steel or galvanized steel with a yield strength greater than or equal to 500 MPa, for example s355 steel with a tensile breaking strength (Rm) greater than or equal to 500 MPa.

[0057] According to an unshown variant, the nut 40 is formed not between the collar 30 and the second threaded portion 50, but at the distal end of the second threaded portion 50, so that the distal end of the body 10 of the fastener 1 is formed by a nut. This nut typically has a polygonal cross-section inscribed in a circle of diameter D6 such that D6 < D2. Positioning the nut 40 between the collar 30 and the second threaded portion 50, however, limits the stresses applied to the body 10 of the fastener 1 when screwing it into a tree trunk, and also establishes a maximum limit for the insertion of the fastener 1 into a tree trunk.

[0058] There figure 2 presents another example of a fastening element 100, which can notably be used in conjunction with the fastening element 1 as previously presented.

[0059] This other example of a fastening element 100 includes a body 110 extending along a longitudinal direction defined by a longitudinal axis XX. In the following description, elements extending axially will be understood as elements extending along the longitudinal axis XX, and elements extending radially will be understood as elements extending radially with respect to the longitudinal axis XX.

[0060] A proximal end 102 and a distal end 104 are arbitrarily defined for the body 110 along the longitudinal axis XX; these designations are purely arbitrary. The proximal and distal ends of the various elements will subsequently be defined with respect to these two ends of the body 10.

[0061] The fixing element 100 comprises successively, from its proximal end 102 to its distal end 104, a first threaded portion 120, a central portion 130, and a second threaded portion 150.

[0062] The first threaded portion 120 is similar or identical to the first threaded portion 20 already described with reference to the figure 1 .

[0063] The first threaded section 120 includes a thread adapted for insertion into wood-like materials, typically a tree trunk. The thread on this first section typically has a maximum diameter of 24 mm, trapezoidal threads with a 60° angle, a thread crest of 1.5 mm, and a pitch of 8 mm. The first threaded section 120 features a wood-type thread, with a root diameter of 16, 17, or 20 mm, a thread crest of 22, 24, or 27 mm, and a pitch of 6, 8, or 9 mm.

[0064] The first threaded portion 120 has a maximum diameter D101 with respect to the longitudinal axis XX, this diameter typically corresponding to the diameter of a cylinder of revolution tangent to the tops of the threads of the first threaded portion 120. The diameter D101 is typically equal to 24 mm, or more generally between 20 mm and 30 mm, or for example between 22 mm and 26 mm.

[0065] One end of the first threaded portion 120, forming the proximal end 102 of the body 110 of the fastening element 1, can typically form a point, so as to facilitate its penetration into a tree, or can be in the form of a truncated point.

[0066] The first threaded portion 120 typically has a length along the axial direction of between 60 mm and 120 mm, for example between 70 mm and 110 mm, or more precisely between 75 and 100 mm, or between 80 mm and 90 mm, or for example equal to 85 mm.

[0067] The central portion 130 is typically a portion having the shape of a cylinder of revolution of diameter D103 around the longitudinal axis XX.

[0068] The diameter D103 is typically equal to D101.

[0069] The second threaded portion 150 has a maximum diameter D102 with respect to the longitudinal axis XX, this diameter typically corresponding to the diameter of a cylinder of revolution tangent to the vertices of the threads of the second threaded portion 150. The diameter D102 is typically equal to D101 and D103.

[0070] The second threaded portion 150 typically has an M24-ISO type thread.

[0071] The second threaded portion 150 typically has a length L150 measured along the axial direction between 30 mm and 80 mm, or between 40 mm and 60 mm, for example equal to 50 mm.

[0072] The second threaded portion 150 typically has a distal end on which a chamfer is made, this distal end of the second threaded portion 50 forming the distal end 12 of the body 10 of the fixing element 4. The chamfer thus made typically has an angle of 30° with respect to the axial direction, and extends over a length between 2 mm and 4 mm, or for example equal to 3 mm along the axial direction.

[0073] The fixing element 100 thus represented on the figure 2 can in particular be used in addition to the fastening element 1 as already described with reference to the figure 1 , particularly in cases where the tree in which it is inserted is deteriorating or dying.

[0074] The presence of a central cylindrical portion 130 of revolution, and therefore without thread, makes it possible to ensure a spacing between the trunk of the tree and the structures or equipment fixed by means of the fixing element 100.

[0075] There figure 3 presents another example of a fastening element 200. The different parts of the fastening element 200 are designated here in the same way as for the fastening element already described with reference to the figure 1 , the numerical references being incremented by 200. The different parts of the fixing element are described below, from a proximal end 202 to a distal end 204 along the longitudinal axis XX.

[0076] The first threaded portion 220 is similar or identical to the first threaded portion 20 already described with reference to the figure 1 .

[0077] The first threaded section 220 includes a thread adapted for insertion into wood-like materials, typically a tree trunk. The thread on this first section typically has a maximum diameter of 22 mm, triangular threads with a 60° angle, a thread height of 3 mm, and a pitch of 9 mm. The first threaded section 220 features a wood-type thread, with a root diameter of 16, 17, or 20 mm, a thread height of 22, 24, or 27 mm, and a pitch of 6, 8, or 9 mm.

[0078] The first threaded portion 220 has a maximum diameter D201 with respect to the longitudinal axis XX, this diameter typically corresponding to the diameter of a cylinder of revolution tangent to the tops of the threads of the first threaded portion 220. The diameter D201 is typically equal to 22 mm, or more generally between 16 mm and 30 mm, or for example between 20 mm and 24 mm.

[0079] In the illustrated example, the first threaded portion 220 forms a free end 202 of the fixing element 200 with a flat section along a plane perpendicular to the longitudinal axis XX.

[0080] The first threaded portion 220 typically has a length along the axial direction of between 50 mm and 120 mm, for example between 50 mm and 110 mm, or more precisely between 60 and 100 mm, or even between 70 mm and 90 mm, or for example equal to 80 mm.

[0081] The collar 230 has a cylindrical shape of revolution with diameter D203 around the longitudinal axis XX. The collar 230 has a diameter D203 which is strictly greater than D201, for example such that D203 > 1.3 D201, or D203 > 1.5 D201.

[0082] The diameter D203 is typically between 30 mm and 60 mm, or between 35 mm and 50 mm, or more precisely between 35 mm and 45 mm, or for example equal to 40 mm.

[0083] The collar 230 typically has a length Lc along the axial direction, typically between 10 mm and 30 mm, or for example between 12 mm and 20 mm, for example equal to 15 mm.

[0084] A spacer section 260 is formed following the collar 230. The spacer section 260 is typically cylindrical in revolution about the longitudinal axis XX. It has a diameter D206 typically between 16 and 30 mm, for example between 20 and 25 mm, or between 22 and 23 mm, or for example equal to 22.5 mm. The diameter D206 is such that D206 < D203.

[0085] The 260 spacing section typically has a length along the axial direction, typically between 50 mm and 100 mm, or for example between 60 mm and 90 mm, or even between 60 and 80 mm, for example equal to 70 mm.

[0086] The fixing element 200 then includes a second threaded portion 250.

[0087] The second threaded portion typically has an M20x2.5 type thread according to the ISO standard.

[0088] The second threaded portion 250 has a maximum diameter D202 with respect to the longitudinal axis XX, this diameter typically corresponding to the diameter of a cylinder of revolution tangent to the tops of the threads of the second threaded portion 250.

[0089] The second threaded portion 250 typically has a length along the longitudinal axis XX of between 100 and 150 mm, or between 110 and 140 mm, or for example between 120 and 140 mm, or for example equal to 130 mm.

[0090] The distal end 204 of the fastening element 202 is here formed by a nut 240. This nut 240 then typically has a polygon cross-section inscribed in a circle of diameter D206 such that D206 < D202.

[0091] In the illustrated example, the transition between the first threaded portion 220 and the collar 230, and the connection between the collar 230 and the spacer section 260, is formed by a fillet, typically with a radius between 5 and 10 mm, or for example, 8 mm. It is understood that the fillet radius is adjusted according to the dimensions of the different sections of the fastener 200. Such fillets are optional and improve the mechanical strength of the fastener by preventing stress concentrations in areas of potential failure between different diameters.

[0092] The fixing element 200, as presented, performs a function similar to that already shown with reference to the figure 1The 260 spacer section ensures spacing between a tree trunk into which the 200 fixing element is inserted and elements fixed to the second threaded portion 250, in particular to guarantee sufficient space for tree growth.

[0093] The fixing elements as proposed can be used to secure various structures to wooden supports such as trees. Examples of such structures include platforms or elements of adventure courses or treetop trekking, cabins, lifeline systems, or zip lines.

[0094] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

[0095] It is also evident that all the characteristics described with reference to a process are transposable, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a process.

Claims

1. A fixing element (1) adapted to be partially inserted into a shaft, comprising a body (10) extending along a longitudinal direction defined by a longitudinal axis (X-X), said body (10) comprising successively, from a proximal end (12) to a distal end (14) along the longitudinal direction: - a first threaded portion (20), adapted for insertion into a shaft frustum, - a flange (30), - a nut (40), - a second threaded portion (50), wherein - the first threaded portion (20) and the second threaded portion (50) have maximum diameters D1 and D2 respectively with respect to the longitudinal axis, - the flange (30) has a cylindrical shape of revolution with a diameter D3 along the longitudinal axis, such that D3 > 1.3 D1, and D3 > 1.3 D2, and a length Lc along the longitudinal direction comprised between 30 mm and 90 mm, - the nut (40) has a section along a plane perpendicular to the longitudinal axis (X-X) inscribed in a regular polygon, said regular polygon being inscribed in a circle with a diameter D4, such that D4 < D3, and D4 > D2, - said fixing element (1) being made in one piece.

2. The fixing element (1) according to claim 1, wherein the diameters D1 and D3 are comprised between 15 and 40 mm.

3. The fixing element (1) according to any of claims 1 or 2, comprising a first transition portion (23) interposed between the first threaded portion (20) and the flange (30), the first transition portion (23) forming a fillet.

4. The fixing element (1) according to any of claims 1 to 3, comprising a second transition portion (45) interposed between the nut (40) and the second threaded portion (50), the second transition portion (45) forming a fillet.

5. The fixing element (1) according to any of claims 1 to 4, wherein the diameters D3 and D4 are such that D4 < 0.8 D3.

6. The fixing element (1) according to any of claims 1 to 5, wherein the first threaded portion (20) has a wood type threading, with a thread root of 16, 17 or 20 mm, a thread top of 22, 24 or 27 mm, and a pitch of 6, 8 or 9 mm.

7. The fixing element (1) according to any of claims 1 to 6, wherein the second threaded portion (50) has an M22-ISO type threading.

8. The fixing element (1) according to any of claims 1 to 7, formed of steel or stainless steel, for example 303 / 304 stainless steel or galvanized steel, or s355 steel with a tensile strength greater than or equal to 500 MPa.

9. The fixing element (1) according to any of claims 1 to 8, wherein the flange (30) comprises a slot (34) extending around its periphery, the slot (34) extending at a distance from a proximal end of the flange comprised between 0.2 and 0.5 Lc, where Lc is the length of the flange measured along the longitudinal axis (X-X).

10. The fixing element (1) according to any of claims 1 to 9, wherein the nut (40) has a section along a plane perpendicular to the longitudinal axis (X-X) defining a regular polygon whose vertices have been truncated.