Abstract
A method of producing an assembly for use in a structural element of a fiber-reinforced material includes providing a core element including an inner core and a circumferential cover, the core element having an end part; producing a subassembly by receiving and centering the end part of the core element into a conforming end recess of a bolt fixture; fixing the bolt fixture to the end part of the core element in the subassembly by circumferentially covering the subassembly with a casing formed of cured fiber-reinforced resin; and machining the subassembly circumferentially covered within the casing.
Claims
1. A method of producing an assembly for use in a structural element made of a fibre-reinforced material, said method comprising the steps of: i) providing an elongated core element including an inner core of a first material, and a cover circumferentially encircling said inner core and made of a second material being a fibre-reinforced material compatible with the fibre-reinforced material of said structural element, said elongated core element having an end part that is at least partially conical in shape, said end part defining a central end face exposing said inner core and a circumferential end face encircling said central end face and exposing said cover; ii) providing a bolt fixture comprising an end recess having a shape conforming to the shape of said end part of said elongated core element; iii) producing a subassembly by receiving and centering said end part of said core element in said end recess of said bolt fixture so as to bring both said central end face and said circumferential end face into contact with said bolt fixture within said end recess; iv) fixing said bolt fixture to said end part of said core element in said subassembly by circumferentially covering said subassembly with a casing formed of cured fibre-reinforced resin circumferentially encircling said subassembly; and v) machining said subassembly circumferentially covered within said casing for providing said assembly including said elongated core element and said bolt fixture.
2. The method according to claim 1, wherein said end part defines an axial distance and a radial distance, said axial distance being larger than said radial distance.
3. The method according to claim 1, wherein said first material is at least one of softer and lighter than said second material, said first material being selected from the group consisting of balsa wood and foamed polymer material.
4. The method according to claim 1, wherein said step of fixing said bolt fixture to said end part of said core element is performed by pulling said subassembly through a pultruder, circumferentially covering said subassembly with reinforcing fibres and resin, and curing said resin to form said casing.
5. The method according to claim 1, wherein said step of fixing said bolt fixture to said end part of said core element is performed by adhering said subassembly to a casing that has been produced in a separate pultrusion process.
6. The method according to claim 1, wherein said step of providing said elongated core element comprises the step of cutting said elongated core element from a continuous, elongated core element body having a circular cross-sectional configuration.
7. The method according to claim 1, wherein said elongated core element has first and second respective end parts each configured for receiving a respective bolt fixture, wherein said steps ii) to iv) comprise mounting and fixing a bolt fixture at each of said first and second respective end parts of said elongated core element, and wherein said step v) comprises machining said subassembly circumferentially covered within said casing into two halves.
8. The method according to claim 1, wherein said casing has a cross-sectional shape selected from the group consisting of circular, square, polygonal, and elliptical.
9. The method according to claim 1, wherein said step v) further comprises the step of machining said casing into a circular or an elliptical cross-sectional configuration.
10. The method according to claim 1, wherein said bolt fixture has a corrugated outer surface.
11. A method of producing a fixation assembly for use in a structural element made of a fibre-reinforced material, said method comprising the steps of: i) providing an elongated core element comprising an inner core of a first material, and a cover circumferentially encircling the inner core and made of a second material that is a fibre-reinforced material compatible with the fibre-reinforced material of said structural element, said elongated core element having an end part configured for the mounting and fixation of a bolt fixture; ii) providing a bolt fixture for the fixation of said structural element to another structural element; iii) producing a subassembly by mounting said bolt fixture on said end part of said elongated core element; iv) fixing said bolt fixture to said end part of said core element in said subassembly by circumferentially covering said subassembly with a casing formed of cured fibre-reinforced resin circumferentially encircling said subassembly; v) producing a first assembly including said elongated core element and said bolt fixture by machining said subassembly circumferentially covered within said casing, said first assembly defining a first longitudinal axis and a first convex surface along the first longitudinal axis; vi) repeating said steps i-v for producing a second assembly defining a second longitudinal axis and convex surface along the second longitudinal axis; vii) producing a spacer of a material compatible with the fibre-reinforced material of said structural element, said spacer having a first concave surface corresponding to said first convex surface of said first assembly and a second concave surface corresponding to said second convex surface of said second assembly; and viii) producing a fixation assembly by positioning and adhering said spacer between said first assembly and said second assembly such that said first concave surface contacts said first convex surface and said second concave surface contacts said second convex surface.
12. The method according to claim 11, wherein said convex and concave surfaces define a circular arc.
13. The method according to 11, further comprising repeating said steps i-v for producing a third assembly defining a third longitudinal axis and a third convex surface along the third longitudinal axis, said spacer having a third concave surface corresponding to said third convex surface of said third assembly, said step viii) comprising contacting said third concave surface to said third convex surface, thereby providing said first, second and third assemblies in a triangular configuration within said fixation assembly.
14. The method according to claim 11, wherein said step of fixing said bolt fixture to said end part of said core element is performed by pulling said subassembly through a pultruder, circumferentially covering said subassembly with reinforcing fibres and resin, and curing said resin to form said casing.
15. The method according to claim 11, wherein said step of fixing said bolt fixture to said end part of said core element is performed by adhering said subassembly to a casing that has been produced in a separate pultrusion process.
16. The method according to claim 11, wherein said step of providing said elongated core element comprises the step of cutting said elongated core element from a continuous, elongated core element body having a circular cross-sectional configuration.
17. The method according to claim 11, wherein said elongated core element has first and second respective end parts each configured for receiving a respective bolt fixture, wherein said steps ii) to iv) comprise mounting and fixing a bolt fixture at each of said first and second respective end parts of said elongated core element, and wherein said step v) comprises machining said subassembly circumferentially covered within said casing into two halves.
18. The method according to claim 11, wherein said casing has a cross-sectional shape selected from the group consisting of circular, square, polygonal, and elliptical.
19. The method according to claim 11, wherein said step v) further comprises the step of machining said casing into a circular or an elliptical cross-sectional configuration.
20. The method according to claim 11, wherein said bolt fixture has a corrugated outer surface.
21. A method of producing a structural element made of a fibre-reinforced material and including a plurality of bolt fixtures for the fixation of said structural element to another structural element of fibre-reinforced material, said method comprising the steps of: i) producing a fixation assembly by a method comprising the steps of: (a) providing an elongated core element comprising an inner core of a first material, and a cover circumferentially encircling the inner core and made of a second material that is a fibre-reinforced material compatible with the fibre-reinforced material of said structural element, said elongated core element having an end part configured for the mounting and fixation of a bolt fixture; (b) providing a bolt fixture for the fixation of said structural element to another structural element; (c) producing a subassembly by mounting said bolt fixture on said end part of said elongated core element; (d) fixing said bolt fixture to said end part of said core element in said subassembly by circumferentially covering said subassembly with a casing formed of cured fibre-reinforced resin circumferentially encircling said subassembly; (e) producing a first assembly including said elongated core element and said bolt fixture by machining said subassembly circumferentially covered within said casing, said first assembly defining a first longitudinal axis and a first convex surface along the first longitudinal axis; (f) repeating said steps (a) through (e) for producing a second assembly defining a second longitudinal axis and convex surface along the second longitudinal axis; (g) producing a spacer of a material compatible with the fibre-reinforced material of said structural element, said spacer having a first concave surface corresponding to said first convex surface of said first assembly and a second concave surface corresponding to said second convex surface of said second assembly; and (h) producing a fixation assembly by positioning and adhering said spacer between said first assembly and said second assembly such that said first concave surface contacts said first convex surface and said second concave surface contacts said second convex surface; ii) positioning said fixation assembly according to an intended position of said fixation assembly within final structural element; and iii) producing said structural element including said fixation assembly in a process including one of extrusion, pultrusion, and a fibre-reinforcing technique.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The present invention is now to be further described with reference to the drawings, in which
(2) FIG. 1 is a partly sectional, perspective and schematic view of a first embodiment of an assembly from which two bolt fixture, bolt or fitting assemblies is produced.
(3) FIG. 2 is a schematic and perspective view illustrating a first step of a method of producing the assembly shown in FIG. 1 including machining a pultruded body into a plurality of core elements,
(4) FIG. 3 is a schematic and perspective view illustrating a second step of the method of producing the assembly shown in FIG. 1 including mounting bolt fixtures at opposite ends of the core element produced in the step shown in FIG. 2,
(5) FIG. 4 is an overall perspective and schematic view illustrating a third step of the method of producing the assembly shown in FIG. 1 constituting a process of providing in a continuous pultrusion process a body from which the assembly shown in FIG. 1 is cut as is illustrated in the right-hand part of FIG. 4,
(6) FIG. 5 is a schematic view illustrating a step of cutting the assembly shown in FIG. 1 and in the right-hand part of FIG. 4 into two bolt fixture assemblies,
(7) FIG. 6 is a vertical sectional view illustrating the assembly shown in FIG. 1 and the bolt fixture assemblies produced from the assembly as shown in FIG. 5,
(8) FIG. 7 is a schematic view illustrating the intentional application of the bolt fixture assembly shown in FIGS. 5 and 6 for the production of a major fibre reinforced structure such as a wind mill element, a bridge part, a building element, the bolt fixtures being positioned along the arc of a circle,
(9) FIG. 8 is a perspective and schematic view similar to the view of FIG. 7 illustrating a slightly modified embodiment of the bolt fixture assembly used for the production of a fibre reinforced element in which the bolt fixtures are positioned along a rectilinear track,
(10) FIG. 9 is a perspective and schematic view of a segment of a structural element produced from the assembly shown in FIG. 8 illustrating the fixture of the fibre reinforced structural element to an I-beam by means of bolts and knots,
(11) FIG. 10 is a perspective and schematic view illustrating the fixation of the fibre reinforced structural element produced from the assembly shown in FIG. 7 having the bolt fixtures positioned along the arch of a circle,
(12) FIGS. 11a, 11b and 11c are perspective, schematic and partly sectional views illustrating three alternative embodiments of improving the fixation of the bolt fixtures in the pultrusion process,
(13) FIGS. 12a and 12b are perspective and schematic views illustrating a distance element and the use of a distance element in the pultrusion process,
(14) FIG. 13 is an overall perspective and schematic view similar to the view of FIG. 4 illustrating the method of producing a presently preferred assembly having a square cross-sectional configuration,
(15) FIGS. 14a and 14b are schematic, perspective and partly sectional views illustrating differently configured bolt fixtures fixated within the pultrusion end casing,
(16) FIG. 15 is a perspective, schematic and partly sectional view of two adjacent parts of an assembly from which end parts two assemblies having protruding bolt pins are produced,
(17) FIGS. 16a and 16b are perspective, schematic and partly sectional views similar to the view of FIG. 15 of a further embodiment of the assembly according to the present invention in which embodiment a fitting is embedded within the pultrusion encasing for the generation of an internal thread within the pultrusion casing,
(18) FIG. 17 is a perspective, schematic and partly sectional view of a further application of the assembly according to the present invention used as a roller of a roller belt,
(19) FIG. 18 is a schematic and perspective view of a differently configured assembly produced in accordance with the method as illustrated in FIG. 13 and shaped in an H-beam configuration,
(20) FIG. 19 is a perspective and schematic view illustrating the utilisation of the technique of producing a load-bearing assembly in accordance with the teachings of the present invention for use as a load sensor,
(21) FIG. 20 is a diagram illustrating the electronics of the load sensor part of the assembly illustrated in FIG. 19,
(22) FIG. 21 is a schematic and diagrammatic view illustrating the use of the assembly shown in FIG. 19 as a load-bearing sensor within e.g. a bridge,
(23) FIG. 22 is a schematic view illustrating a different application of the load-carrying assembly illustrated in FIG. 19 within a bridge, and including a parallel link to a PC-based measuring station,
(24) FIG. 23 is a perspective, schematic and partly sectional view of a further embodiment of the assembly according to the present invention configured as an insulator for a high voltage cable,
(25) FIG. 24 is a perspective and schematic view illustrating the intentional application of the insulator shown in FIG. 23,
(26) FIG. 25A is a perspective view similar to the view of FIG. 3 illustrating the components of a further embodiment of a sub-assembly of the presently preferred embodiment of the bolt fixture assembly or bolt assembly according to the present invention,
(27) FIG. 25B is a vertical sectional view of the sub-assembly shown in FIG. 25A,
(28) FIG. 26A is a perspective view similar to the view of FIG. 25A illustrating the sub-assembly of FIGS. 25A and 25B in a state of having the components joined together,
(29) FIG. 26B is a vertical sectional view similar to the view of FIG. 25B of the sub-assembly shown in FIG. 26A,
(30) FIG. 27A is a perspective view similar to the views of FIG. 25A and FIG. 26A of the presently preferred embodiment of the bolt fixture assembly or bolt assembly according to the present invention,
(31) FIG. 27B is a vertical sectional view of the bolt fixture assembly or bolt assembly shown in FIG. 27A
(32) FIG. 28A is a perspective view of a bolt fixture assembly or bolt assembly shown in FIG. 27A after it has been cut as shown in FIG. 5.
(33) FIG. 28B is a vertical sectional view of the assembly of FIG. 28A.
(34) FIG. 29 is a vertical sectional view of the assembly shown in FIG. 28B in which a threaded rod is fixated.
(35) FIG. 30 is a perspective view of a fixation assembly including a plurality of bolt fixture assemblies and concave spacers.
(36) FIG. 31 is a perspective view of a curved fixation assembly including a plurality of bolt fixture assemblies and concave spacers.
(37) FIGS. 32A, 32B and 32C are top views of a curved fixation assembly, a straight fixation assembly and a box shaped fixation assembly, respectively.
(38) FIG. 33 is a top view of a fixation assembly including a plurality of elliptical bolt fixture assemblies and concave spacers.
(39) FIG. 34 is a perspective view of a wind power plant.
(40) FIG. 35 is perspective view of the hub and wing interface of the wind power plant of FIG. 34.
DETAILED DESCRIPTION
(41) The present invention constitutes an improvement and a refinement of the technique described in EP 1 467 853 and U.S. Pat. No. 7,357,725 to which reference is made.
(42) According to the method of producing an assembly including a bolt fixture of bolt for use in a fibre reinforced structural element, a core element is initially produced. The core element may be produced form any relevant material including plastics based materials, wood or metal or composite materials which materials are compatible with the materials of the fibre reinforced structural element meaning that the materials of the core element like all other materials used in accordance with the technique of the present invention are combinable with the remaining materials i.e. do not react with one another in a chemical process, and a mechanically combinable or linkable meaning that the materials may be joined together in an integral structure and preferably exhibit substantial identical mechanical characteristics as far as coefficients of expansion, and mechanical strength such as tear and shear strengths are concerned. In accordance with the presently preferred embodiment of the method according to the present invention, a pultruded core element is preferably used as is illustrated in FIG. 2.
(43) In FIG. 2, a pultruder is designated the reference numeral 30 in its entity and delivers from its output a pultrusion rod 32 i.e. a rod of circular cylindrical cross-sectional configuration made from resin such as a polyester, vinyl ester or phenol or epoxy resin in which reinforcing fibres such as glass fibre, carbon fibre or kevlar fibres are embedded. The pultrusion rod or body 32 is cut into individual core elements, one of which is designated by the reference numeral 12, by means of a cutter illustrated schematically as a saw 34. At opposite ends of the body or core element 12, conical end parts are produced by means of a machining device such as a cutter 36 illustrated schematically in FIG. 2. The cutter 36 produces the conical end parts designated by the reference numeral 20 at opposite ends of the core element 12.
(44) In a further step of the method of producing the assembly 10 shown in FIG. 3, bolt fixtures 22 are positioned at opposite ends 20 of the core element 12 as is illustrated in FIG. 3.
(45) Like the core element 12, the bolt fixtures 22 are preferably of a circular cylindrical cross-sectional configuration having at the one end a conical recess 20 configured in conformity with the conical end part 20 of the core element 12. Each of the bolt fixtures 22 is further provided with a through-going bore communicating with the conical recess 20 and defining a narrow central cylindrical bore part 25 and a wider threaded bore part 24 communicating with the exterior and intended to co-operate with a threaded shaft 28 as is illustrated in the lower left-hand part of FIG. 3. The bolt fixtures may be differently configured as the bolt fixtures may e.g. be of an overall conical configuration tapering from the one end towards the other end e.g. from the outer end towards the inner end or from the inner end towards the outer end. Alternatively, the bolt fixtures 22 may be provided with outwardly protruding flanges. Further alternatively, the bolt fixtures may have a differently configured through-going bore in which the threaded bore part 24 communicates with the conical recess without the intermediate narrow cylindrical bore part 25. Further alternatively, the threaded bore part 24 may be omitted as the bolt fixture may be provided as a fixture having an outwardly protruding threaded shaft constituting a bolt.
(46) By the provision of the co-operating conical end part and the conical recess 20 of each of the bolt fixtures 22, a self-centering and self-aligning feature is obtained, as the bolt fixtures 22 due to the co-operation between the conical end part 20 and the conical recess 20, tend to be maintained in the intentional aligned orientation in which the circular cylindrical bolt fixtures 22 are constituting cylindrical continuations of the central part of the core element 12.
(47) The subassembly comprising the core body and the two bolt fixtures 22 illustrated in FIG. 3 is, as is illustrated in FIG. 4, introduced into a pultrusion apparatus 40 comprising a receiving section 46 in which the subassembly described above along with a plurality of subassemblies together constituting a continuous string is introduced into the receiving section 46 of the pultrusion apparatus 40 together with webs of fibre reinforcing materials which webs are shown in the left-hand part of FIG. 4 and two of which are designated the reference numerals 42 and 44. From the receiving section 46, a string 48 including the aligned sub-assemblies circumferentially encircled by the fibre reinforcing materials is introduced into a resin applicator and resin heating and curing apparatus 50 communicating with a resin reservoir 52 for the supply of resin thereto. An output die of the apparatus 50 is designated the reference numeral 54 and provides a specific configured shaping of the of a pultrusion string 56 delivered from the die 54 apparatus 50 which string 56 is introduced into a puller apparatus 58 for pulling the pultrusion string from the die 54 of the apparatus 50.
(48) From the puller 58, the string 56 is delivered to a cutter 60 which separates the string 56 into distinct sections constituting the assembly 10 also shown in FIG. 1 as the cutting of the string 56 in the sections or assemblies 10 is synchronised with the entry of the subassembly comprising the core body 12 provided with the end part covering bolt fixtures 22 to the entry end of the pultrusion apparatus 40. In an alternative process of producing the subassembly from which the assembly 10 shown in FIG. 1 is produced, the bolt fixtures 22 and the core element 12 are fixated through adhesion to a cylindrical casing preferably produced through pultrusion and constituting the casing 26 described above. It is contemplated that the fixation through adhesion to the casing 26 produced through pultrusion and the technique of fixing the bolt fixtures 22 and the core element 12 to the casing through the pultrusion process constitute technical equivalencies.
(49) In FIG. 1, the core element 12 is shown together with the bolt fixture 22 disclosing the threaded bore 24 communicating with the bore 25 and further disclosing the tapering or conical end part 20 of the core element 12.
(50) In FIG. 1, the outer casing produced in the pultrusion process described above with reference to FIG. 4 is also disclosed, which casing is designated the reference numeral 26. FIG. 1 further discloses the configuration of the assembly 10 which configuration defines a concave top-surface 14, an opposite convex or circular cylindrical bottom surface 16 and opposing parallel planar surfaces 18. The convex/concave configuration illustrated in FIG. 1 allows, as will be described below with reference to FIGS. 7 and 10, the positioning of the bolt fixture assembly produced from the assembly 10 by arranging the convex outer surface 16 or one bolt fixture assembly juxtaposed and partly received within the concave surface 14 of the adjacent bolt fixture assembly.
(51) From the assembly 10 shown in FIG. 1, two bolt fixture assemblies are produced as is illustrated in FIG. 5 by cutting the assembly 10 into two parts along a line indicated in dotted line by the reference numeral 64. The cutter is schematically illustrated by a saw 62. The assembly 10 cut into two halves is illustrated in FIG. 6 in a vertical sectional view disclosing the line of separation 64 providing opposite sloping surfaces 66 of each of the two bolt fixtures assemblies produced from the assembly 10. Each bolt fixture assembly constituting one half of the assembly 10 includes a tapering cut part of the core element 12 and the bolt fixture 22 fixated to the core element 12 by the pultrusion encasing 26. By provision of the sloping surface 66 an irregularly shaped bolt fixture assembly is produced enhancing the ability of fixation of the bolt fixture assembly within the final fibre reinforce structure and further providing a major surface of contact between the central core element 12 and the final fibre reinforced structure.
(52) The ability of positioning the individual bolt fixture assemblies in an orientation different from a rectilinear orientation is illustrated in FIG. 7 as three individual bolt fixture assemblies combined into a structure in its entity designated the reference numeral 70 is shown and including three bolt fixture assemblies positioned having the concave surface 14 of one bolt fixture assembly receiving in the convex surface 16 of the adjacent bolt fixture assembly in an overall angular orientation. The fibre reinforced structure encasing the composite structure shown in FIG. 7 is designated the reference numeral 72.
(53) In FIG. 8, a slightly modified configuration of the bolt fixture assembly is illustrated as the circular concave and convex surfaces 14 and 16 are substituted by concave and convex outer surfaces having planar generators. By the planar generator configuration of the convex surface 14 having a configuration corresponding to the configuration of the convex surface 16 of the blot fixture assemblies, the individual bolt fixture assemblies may, as is illustrated in FIG. 8, be combined into a structure in which the proper rectilinear positioning of individual bolt fixture assemblies is ensured and maintained by the provision of the corresponding convex and concave surfaces of the bolt fixture assemblies. The combination of a total of four bolt fixture assemblies in FIG. 8 is in its entirety designated the reference numeral 70. From the composite structure illustrated in FIG. 8, a fibre reinforced structural element is produced in a further extrusion, pultrusion or manual or automated fibre reinforcing production process by the application of reinforcing fibres and resin to the combination of the fixture assemblies and configuring the structural element according to the intentional geometrical of the final product.
(54) The final product is used e.g. as illustrated in FIG. 9 in connection with a load-bearing carrier I-beam 76 in which the bolt shafts 28 received within the bolt fixtures of the bolt fixture assemblies shown in FIG. 8 are fixated to the I-beam 76 by means of individual bolts 74.
(55) The curved structure shown in FIG. 7 may alternatively be used for the fixation to e.g. a planar plate element 78 as illustrated in FIG. 10.
(56) As mentioned above, the bolt fixtures 22 described above with reference to FIGS. 1-6 may advantageously be configured in a conical or elliptical shape for improving the fixation of the bolt fixtures within the pultrusion encasing 26. In FIGS. 11a-11c, different techniques of enhancing the fixation of the bolt fixtures within the pultrusion encasing are illustrated. Generally throughout the specification, components or elements identical to components or elements described previously are designated the same reference numerals as previously designated whereas components or elements geometrically differing from previously described components or elements, respectively, however serving the same purpose of previously described components or elements are designated the same reference integer, however added a marking for identifying the geometrical difference.
(57) In FIG. 11a, the bolt fixture 22 differs from the above described bolt fixture 22 shown in FIG. 3 in that the outer surface of the bolt fixture 22 is of a rough or rugged structure providing an uneven outer surface which improves the fixation of the bolt fixture 22 to the pultrusion casing 26. In FIG. 11a the rough or rugged outer surface of the bolt fixture 22 is for the sake of clarity somewhat exaggerated as compared to real life rough or rugged surfaces.
(58) In FIG. 11b, a different technique of enhancing the fixation of the bolt fixture 22 relative to the pultrusion encasing 26 is shown as the bolt fixture 22 is provided with outer ridges defining a plurality of outer threads of left and right hand configuration serving the purpose of providing a solid embedding of the ridges within the polymer material of the outer pultrusion encasing 26.
(59) In FIG. 11c, a further alternative technique of improving the adhesion between the bolt fixture 22 and the pultrusion encasing 26 is shown. In FIG. 11c, the outer end of the bolt fixture 22 is provided with an outer shallow thread 23 in which reinforcing fibres and resin are received before the bolt fixture 22 together with the core body 12 are moved through the pultruder such as the pultruder further shown in FIG. 4.
(60) In order to facilitate the cutting of the string from which the assemblies according to the present invention are cut such as the string 56 shown in FIG. 4, a distance body such as the body 80 shown in FIG. 12a may be used. Centrally the body 80 comprises centrally a circular cylindrical disc 82 from opposite sides of which two coaxially extending pins 84 protrude. The body 80 is generally used in combination with the bolt fixtures such as two bolt fixtures 22.sup.IV shown in 12b for keeping the adjacent ends of the bolt fixtures 22.sup.IV spaced apart and allowing the cutter to be easily moved through the outer pultrusion encasing, not shown in FIG. 12b, and through the distance body 80 which is preferably a pre-cast plastics body such as a PE, PP or similar plastics material body.
(61) In FIG. 14a, a technique of using a carbon reinforced fitting in combination with a nut is shown. In FIG. 14a, a nut 22.sup.V is encased within the pultrusion encasing 26.sup.V at the outer end of the core body 12.sup.V. In registration with the nut 22.sup.V a carbon fibre reinforced cylindrical bushing or fitting 27 is enclosed within the pultrusion encasing 26.sup.V for allowing the nut 22.sup.V to be kept spaced apart from the outer end of the assembly 10.sup.V and at the same time through the provision of the carbon fibre reinforced bushing 27 providing a rigid assembly.
(62) In FIG. 14b, a different technique of centring the bolt fixture relative to the core body is illustrated as the core body 12.sup.VI is provided with an outer coaxially arranged pin 20.sup.VI on which a bolt fixture or nut 22.sup.VI is mounted.
(63) In FIG. 13, a pultrusion apparatus 40.sup.IV is shown, basically corresponding to the pultrusion apparatus 40 described above with reference to FIG. 4, however differing from the above described apparatus in that in the receiving section 46, the string of core bodies 12.sup.IV and bolt fixtures 22.sup.IV further includes the distance bodies 42 for the production of the string 48.sup.IV including the bolt fixtures 22.sup.IV kept in spaced apart relationship by means of distance bodies 82.
(64) From the curing apparatus 50, a string 56.sup.IV is supplied having a square cross section or configuration as distinct from the above described configuration of the assembly 10.
(65) The technique of providing a distance body 82 for the maintenance of the outer ends of the bolt fixtures 22.sup.IV described above with reference to FIG. 12b may be amended for keeping the outer ends of the bolt pins received within the bolt fixtures in spaced apart relationship.
(66) In FIG. 15, a pre-cast plastics material body 80.sup.VII is provided constituting a circular cylindrical configuration having an outer diameter corresponding to the outer diameter of the bolt fixtures 22.sup.VII and having threaded bores for the receiving of the outer ends of the bolt pins 28.sup.VII. After the finalising of the pultrusion process with the pultrusion apparatus such as the apparatus shown in FIG. 4 or alternatively in FIG. 13, the pultrusion string is cut e.g. by means of the cutter 60 as illustrated in FIGS. 4 and 13 as the cutter is moved into the spacing between the two outer ends of the bolt pins 28.sup.VII received within the distance body 80.sup.VII.
(67) The integral pultrusion technique according to the present invention also allows the usage of the fitting integrally pultruded into the assembly according to the present invention to be used as a generator e.g. for the generation of an inner thread within the pultrusion encasing as is illustrated in FIGS. 16a and 16b.
(68) In FIG. 16a, an end part of an assembly 10.sup.IX according to the present invention is shown including a pultrusion encasing 26.sup.IX in which a core body 12.sup.IX is encased together with a generator body 22.sup.IX which body is composed of a shaft 25.sup.IX extending from the outer end of the assembly 10.sup.IX and including a coarse thread 24.sup.IX which is embedded within the pultrusion encasing 26.sup.IX. The outer surface of the thread 24.sup.IX of the generator fitting 22.sup.IX is provided with a slip coating such as a PTFE coating, a powder covering or a greasy surface coating allowing the generator fitting 22.sup.IX to be removed from the outer end of the assembly 10.sup.IX as is illustrated in FIG. 16b in which the generator fitting 22.sup.IX is disengaged from the remaining part of the assembly 10.sup.IX, exposing the inner thread of the pultrusion encasing 26.sup.IX originally generated by the external thread 24.sup.IX of the generator fitting 22.sup.IX.
(69) The pultrusion encasing 26.sup.IX may be used for receiving e.g. a part of a roller bearing such as a roller bearing 60 illustrated in FIG. 17 and received within the pultrusion encasing 26.sup.IX of the assembly 10.sup.IX, e.g. by means of the threads shown in FIGS. 16a and 16b or alternatively fixated fixed relative to the inner wall of the pultrusion encasing 26.sup.IX by means of an adhesive filling out the cavities of the inner thread of the pultrusion encasing 26.sup.IX as originally generated by the generator fitting 22.sup.IX. The roller bearing 60 comprises a roller bearing part 62 fixated fixed to the outer end of the assembly 10.sup.IX as already described and connected through a shaft 64 to a roller reel 66 supported on e.g. a stand or similar support. At the opposite end of the assembly 10.sup.IX a similar roller bearing 60 is provided. The structure shown in FIG. 17 may e.g. be used for production plants in which a roller band is used and which roller band on the one hand may stand exposure to aggressive liquids or gasses and on the other hand may provide a light weight structure which is easily moved from one location to another.
(70) The integral pultrusion production technique described above also allows the manufacture of elaborated configured structural elements such as an H-shaped structure element 10.sup.X shown in FIG. 18 which is expelled from the curing apparatus 50 of a pultrusion apparatus similar to the apparatus described above with reference to FIGS. 4 and 13. In the H-shaped assembly shown in FIG. 18 two vertical bars are included each having integrally included bolt fixtures, bolts or fittings for allowing the H-shaped element to be fixed to another building structure. Each of the vertical bars of the assembly 10.sup.X is designated the reference numeral 11.sup.X and the horizontal web interconnecting the two vertical bars in the H configuration are designated the reference numeral 13.sup.X.
(71) The technique of providing a load-carrying assembly having fittings, bolt fixtures or bolts positioned at opposite ends for allowing the element or assembly to be used as a load-carrying element according to the teachings of the present invention may further be combined with the technique of measuring the load-carrying capability of the element by integrating a sensor such as a strain gauge or similar impact detecting sensor into the assembly according to the present invention. In FIG. 19, an assembly 10.sup.XI is shown having two threaded pins 28.sup.XI extending from opposite ends of a circular cylindrical pultrusion encasing 26.sup.XI. Within the pultrusion encasing 26.sup.XI two bushings 22.sup.XI are encased for receiving the threaded pins 28.sup.XI. Centrally within the pultrusion encasing 26.sup.XI, a load detector sensor unit 90 is received. The load detector sensor 90 may include a strain gauge or similar impact detecting element and may be implemented as is illustrated in FIG. 20. The load detector sensor unit 90 is connected by two pins 92 to the bushings 22.sup.XI for the transmission of the load from the bushings 22.sup.XI to the load detector unit 90. The load-transmitting pins 92 are each encased within a cylindrical encasing as is indicated in dotted line in FIG. 9 and designated the reference numeral 94.
(72) The load detector sensor unit may be implemented as is illustrated in FIG. 20 included an induction loop 100 for receiving electrical power through induction from an external energising source, which induction loop is connected to a power supply unit 102 for the supply of electrical power to electronic circuitry blocks 104 and 106. The block 104 constitutes an input amp-stage receiving an input signal from a sensor element such as a strain gauge 108 and delivers on its output signal to a transmitter stage 106 which emits a radio wave signal to a remote receiver by means of an aerial 110. It is to be realised that the circuitry included in the load detector sensor unit 90 described above with reference to FIG. 20 may include any conventional signal shaping or signal conversion elements such as non-linear amplification stages, a/d converter stages etc. The technique of providing remote data locking units is well known in the art and no detailed description of the electronic circuitry of the load detector sensor element itself is being given as the implementation of the load detector sensor unit 90 itself is no part of the present invention.
(73) In FIG. 21, two different applications of the load detector sensor unit containing assembly 10.sup.XI is illustrated. In FIG. 21, the one application of the assembly 10.sup.XI is as a structural element for interconnecting two sections of a bridge and the alternative application comprises the use of the assembly 10.sup.XI as a load-carrying element for supporting a wire of the carrying structure of the bridge. In FIG. 21, a receiver station for receiving data from the load detector sensor unit 90 (FIG. 20) is also illustrated comprising a receiver aerial 112 connected to a received stage 114 which deliver on its output an analogue or alternatively a digital signal to a measuring apparatus constituted by a PC designated the reference numeral 116.
(74) In FIG. 22, the usage of a plurality of assemblies 10.sup.XI is illustrated as in FIG. 22, a total of five assemblies 10.sup.XI is used for the suspension of a bridge 120 from a wire 122. In FIG. 22, the data-logging is illustrated as a hard wire connection from each of the assemblies 10.sup.XI to the data logging PC 116 having a total of five parallel inputs 114, as it is contemplated that the wireless transmission technique illustrated in FIG. 21 may readily be modified into a semi hard wire connection by the use of proximity detection technique by the use of a receiver unit positioned juxtaposed each of the assemblies 10.sup.XI for receiving the data or the signals output from the load detector sensor unit and at the same time energising the unit 90 by the supply of energising current to the induction loop 100 of each of the units 90 included in the assemblies 10.sup.XI.
(75) The high load-bearing capability of the assembly according to the present invention also allows the technique to be used for alternative applications such as in a high voltage insulator as is illustrated in FIG. 23 and FIG. 24. In FIG. 23, the assembly described above with reference to FIG. 19 is modified by the omission of the load detector sensor unit 90 and by the introduction of a high voltage insulator core body 12.sup.XII constituted by a sealed hollow encasing in which a highly insulating gas such as SF.sub.6 is included. The insulating core body 12.sup.XII serve the same purpose as the above described core body 12 discussed with reference to FIGS. 1-6. In FIG. 23, the assembly 10.sup.XII further comprises an outer pultrusion encasing 26.sup.XII encasing the insulating core body 12.sup.XII and further two insulating bushings 94.sup.XII encircling and encasing the bushings 22.sup.XII in which the threaded pins 18.sup.XII are received and fixated fixed. In FIG. 23, three bell-shaped outer insulating elements 118.sup.XII are further illustrated serving the purpose of preventing water or moisture from generating short-circuiting paths on the outer surface of the pultrusion encasing 26.sup.XII as is well known in the art per se.
(76) In FIG. 24, the intentionally an intended application of the high voltage insulator assembly 10.sup.XII shown in FIG. 23 is illustrated as the high voltage insulating assembly 10.sup.XII is suspended from a beam 124 for the support of a high voltage wire 126 which is suspended in and supported by a cross shaped fitting 128 which is fixated fixed to the outer end of one of the threaded pins 18.sup.XII (FIG. 23) of the assembly 10.sup.XII.
(77) FIG. 25A shows a perspective view and FIG. 25B a sectional view, respectively, of a further and presently preferred embodiment of a sub-assembly. The sub-assembly comprises an elongated core 12.sup.XIII and two bolt fixtures 22.sup.XIII. The elongated core 12.sup.XIII is in turn composed of an inner core 130 of a soft and light material such as balsa wood or a foamed core of e.g. polyurethane and a cover 132 of fibre reinforced material preferably produced by pultrusion, which is covering the inner core 130. The bolt fixtures 22.sup.XIII are made of steel and positioned adjacent opposite ends of the elongated core element 12.sup.XIII. The ends of the elongated core 12.sup.XIII have truncated conical shapes and are in turn divided into a central end face 134 exposing the inner core 130 and a circumferential end face 196 exposing the cover 132. A part of a further elongated core 12.sup.XIII and a further bolt fixture 22.sup.XIII is shown in the right-hand part of FIGS. 25A and 25B and separated from the right-hand end bolt fixture 22.sup.XIII of the first-mentioned sub-assembly by a distance body or spacer 80.
(78) FIGS. 26A and 26B are views similar to the views of FIGS. 25A and 25B, respectively, illustrating the elements and components shown in FIGS. 25A and 25B, respectively, in an assembled state, in which the bolt fixtures 22.sup.XIII are glued to the opposite ends of the elongated core element 12.sup.XIII
(79) Also shown in connection with FIG. 26B is a zoomed section of the outermost radial interface defining the location of the highest stress 138. The location of the highest stress 138 is located at an interface between the cover 132 and the bolt fixture 22.sup.XIII, thereby two rigid materials, namely the fibre reinforced material and steel, transfer the forces and the soft inner core 130 is not involved.
(80) FIG. 27A shows a perspective view and FIG. 27B a sectional view, respectively, of the final bolt fixture assembly 10.sup.XIII. The assembly 10.sup.XIII has now been completely enclosed by a circular cylindrical casing 140 of fibre reinforced material. Thus, the location of the highest stress is now also completely enclosed by fibre reinforced material. Preferably, the pultrusion technique as shown above is used in order to produce a series of opposing bolt fixture assemblies 10.sup.XIII
(81) FIG. 28A shows a perspective view and FIG. 28B a sectional view, respectively, of a set of a bolt fixture assembly 10.sup.XIII. The series of opposing bolt fixture assemblies 10.sup.XIII has been separated from one another as shown in FIGS. 4 and 13 by cutting through the distance bodies or spacers for producing in a first step two opposing bolt fixture assemblies, and thereafter machined in an acute angle using a saw 62 thereby providing two separate assemblies 10, as shown in FIG. 5.
(82) FIG. 29 shows in an enlarged scale as compared to FIG. 28B the bolt fixture assembly 10.sup.XIII. It can be clearly seen that the circumferential outer surface of the bolt fixture 22.sup.XIII is completely enclosed by the fibre reinforced material. The bolt fixture assembly 10.sup.XIII has been provided with a threaded rod 28.sup.XIII which has been introduced into the threaded bore 24.sup.XIII of the bolt fixture 22.sup.XIII.
(83) FIG. 30 shows a perspective view of a fixation assembly 70. The fixation assembly 70 includes a plurality of bolt fixture assemblies 10.sup.XIII, all designated the same reference numeral. In-between each bolt fixture assembly 10.sup.XIII, a spacer, all designated the reference numeral 142, is located. Each spacer 142 is adhered to a neighbouring bolt fixture assembly 10.sup.XIII in a linear arrangement. Each bolt fixture assembly 10.sup.XIII defines two oppositely located convex surfaces 144 and each spacer 142 defines two oppositely located concave surfaces 146 which correspond to and match the convex surfaces 144 in order to form close fit contact surfaces between the bolt fixture assemblies 10.sup.XIII and the spacers 142. In the present case the convex surfaces 144 and the concave surfaces 146 define circular arcs.
(84) FIG. 31 shows a perspective view of a curved fixation assembly 70. The spacers 142 have been rotated around the axis of the bolt fixture assemblies 10.sup.XIII in order to generate the curvature and subsequently, the convex surfaces 144 have been adhered to the corresponding concave surfaces 146 using a compatible resin or glue.
(85) FIG. 32A shows a top view of a straight fixation assembly 70.sup.III. In order to form the present elongated linear fixation assembly 70.sup.III, the contact surfaces of the bolt fixture assemblies 10.sup.XIII and the spacers 142 and the concave surfaces 146 (FIG. 30) should be facing one another,
(86) FIG. 32B shows a top view of a curved fixation assembly 70.sup.IV. The curved fixation assembly 70.sup.IV resembles the fixation assembly 70 of FIG. 31 except that the first three bolt fixture assemblies 10a 10b 10c form a curve while the remaining bolt fixture assemblies 10.sup.XIII define a straight line. In this configuration the contact surfaces between the respective three bolt fixture assemblies 10a 10b 10c and the corresponding spacers 142A 142B are not facing one another in order to form a bend or curve. Since the convex and concave surfaces match and constitute a cylindrical joint, it is contemplated that bends of between about 120 degrees and 180 degrees may be implemented using the bolt fixtures and spacers as illustrated. Using a smaller spacer will allow a smaller contact surface and thus a smaller angle such as 90 degrees to be implemented.
(87) FIG. 32C shows a top view of a box shaped fixation assembly 70.sup.V. The box shaped fixation assembly 70.sup.V include spacers 142.sup.I, which define three concave surfaces 146 defining a mutual angle of about 120 degrees. Each of the three concave surfaces 146 defines a contact surface against a convex surface of a neighbouring bolt fixture assembly 10.sup.XIII.
(88) FIG. 33 shows a top view of a fixation assembly 70.sup.VI including a plurality of dual bolt fixture assemblies 10.sup.XIV. The total bolt fixture assemblies 10.sup.XIV are not entirely circular but define two oppositely located convex surfaces 146.sup.II both defining circular arcs in the transversal direction. In-between each bolt fixture assembly 10.sup.XIV is located a spacer 142. The dual bolt fixture assembly 10.sup.XIV includes two bores 28.sup.XIV.
(89) In the above context and with reference to FIGS. 30-33, the convex and concave surfaces preferably define a circular arc such that the contact surface defined between the bolt fixture and the spacer may slide along a circular path.
(90) FIG. 34 shows a perspective view of a wind power plant 200. The wind power plant comprises a tower 202, a generator housing 204 on top of the tower 202, a rotating hub 206 connected to the housing 204 and three wings 208 fixated to the hub 206 at a mutual angle of 120 degrees.
(91) FIG. 35 shows a zoomed perspective view of a wind power plant hub 206 and wings 208. The fixation assembly 70.sup.II shown in FIG. 31 has been moulded into the wing 208 of the wind power plant 200 such that the bores of the bolt fixtures 22.sup.XIII are exposed and the casings 140 of the bolt fixture assemblies 10.sup.XIII are bonded to the compatible, fibre reinforced polymeric material of the wing 208. The wing 208 is subsequently bolted to the hub 206 by means of threaded rods 28.sup.XIII which extend into the hub 206 and a securely fastened in the hub, e.g. by using suitable nuts 210. In an alternative application of the fixation technique described above, the technique is used for joining two parts of a larger wing together in an assembled wing structure.
(92) In the present specification, the terms pultrusion and pultruding have been used covering the technique of providing and producing the core element and the subassembly. The terms pultrusion and pultruding, however, are to be construed broadly covering any combined technique of producing fibre reinforced products including techniques known as pullforming, pullwinding etc. Consequently, it is to be understood that any technique covered by the above terms or equivalent techniques comprising continuous, semi-continuous or intermittent production of elements, such as the core element and the subassembly are to be construed equivalences to the pultrusion technique described in the present specification.
(93) Although the present invention has above been described with reference to specific, presently preferred embodiments, numerous modifications and amendments are obvious to a person having skill in the art and such modifications or amendments are to be considered part of the present invention without limiting the scope of the invention to the above described embodiments. Rather is the invention to be construed in the terms of the appending claims.
(94) It is to be realised that the protective scope as defined in the appending claims does not cover the geometrical configuration of the assembly 10 shown in FIGS. 1-6 itself, namely the geometrical outer shape of the cedar plank element whereas differently configured assemblies having specially configured outer surfaces such as the assemblies together constituting the structure shown in FIG. 8 are contemplated to be part of the protective scope as defined in the appending claims.
(95) Points
(96) 1. A method of producing a fibre reinforced structural element including a plurality of bolt fixtures, bolts or fittings for the fixation of said structural element to another structural element, comprising the steps of: i) providing an elongated core element of a material, preferably fibre reinforcement material compatible with the materials of said fibre reinforced structural element, preferably made through pultrusion, having an end part for the mounting or fixation of one of said bolt fixtures, bolts or fittings, ii) mounting said one bolt fixture, bolt or fitting on said end part of said core element for producing a subassembly, iii) fixating said one bolt fixture, bolt or fitting relative to said end part of said core element in a pultrusion process by pulling said subassembly through a pultruder, by circumferentially covering said subassembly with reinforcing fibres and resin and by heating and curing said resin for causing said resin to provide in conjunction with said reinforcing fibres a casing circumferentially encircling said subassembly, or alternatively fixating said subassembly by adhesion to said encasing produced in a separate pultrusion process, iv) machining said subassembly circumferentially encircled within said casing of said reinforcing fibres and said cured resin for providing a bolt fixture, bolt assembly or fitting assembly including said core element and said one bolt fixture, bolt or fitting and said core element, v) repeating said steps i-iv for producing a plurality of said bolt fixtures, bolt assemblies or fitting assemblies, vi) positioning said plurality of assemblies according to the intentional position of said plurality of bolt fixtures, bolts or fittings within said final fibre reinforced structural element, and vii) producing said fibre reinforced structural element including said plurality of bolt fixtures, bolts or fittings constituted by said pluralities of assemblies in an extrusion, a pultrusion or a fibre reinforcing production technique. 2. The method according to point 1, said step i) of providing said elongated core element comprising the step of cutting said elongated core element from a continuous, elongated core element body. 3. The method according to any of the points 1 and 2, said elongated core element having respective end parts for receiving a respective bolt fixture, bolt or fitting at said respective end parts, said steps ii) and iii) comprising mounting and fixating two bolt fixtures, bolts or fittings at said respective end parts of said core element of said subassembly, and said step iv) comprising machining said subassembly circumferentially encircled within said casing of said reinforcing fibres and said cured resin into two halves each constituting a bolt fixture, bolt or fitting assembly. 4. The method according to any of the points 1-3, said step i) further comprising the step of machining said end part into a specific configuration for the receiving and centring of said bolt fixture, bolt or fitting having an end recess part congruent with said specific configuration of said end part of said core element. 5. The method according to any of the points 1-4, said casing being produced in step iii) having a specific cross-sectional configuration such as a circular, an elliptical, a polygonal, in particular a hexagonal or square cross-sectional configuration or alternatively a combination of the above mentioned cross-sectional configurations. 6. The method according to any of the points 1-5, said step iv) further comprising the step of machining said casing into a specific cross-sectional configuration such as a circular, an elliptical, a polygonal, in particular a hexagonal or square cross-sectional configuration or alternatively a combination of the above mentioned cross-sectional configurations. 7. The method according to any of the points 1-6, said step iv) comprising the step of providing said bolt fixture, bolt assembly or fitting assembly having an end surface part defining an acute angle relative to the longitudinal axis of said bolt fixture or bolt assembly. 8. A method of producing a bolt fixture, bolt assembly or fitting assembly for use in a fibre reinforced structural element including a plurality of bolt fixtures, bolts or fittings for the fixation of said structural element to another structural element, comprising the steps of: i) providing an elongated core element of a material, preferably fibre reinforcement material compatible with the materials of said fibre reinforced structural element, preferably made through pultrusion, having an end part for the mounting or fixation of one of said bolt fixtures, bolts or fittings, ii) mounting said one bolt fixture, bolt or fitting on said end part of said core element for producing a subassembly, iii) fixating said one bolt fixture, bolt or fitting relative to said end part of said core element in a pultrusion process by pulling said subassembly through a pultruder, by circumferentially covering said subassembly with reinforcing fibres and resin and by heating and curing said resin for causing said resin to provide in conjunction with said reinforcing fibres a casing circumferentially encircling said subassembly, or alternatively fixating said subassembly by adhesion to said encasing produced in a separate pultrusion process, and iv) machining said subassembly circumferentially encircled within said casing of said reinforcing fibres and said cured resin for providing a bolt fixture, bolt assembly or fitting assembly including said core element and said one bolt fixture, bolt or fitting and said core element. 9. The method according to point 8 of producing a bolt fixture, bolt assembly or fitting assembly further comprising any of the features of the method of producing a fibre reinforced structural element according to any of the points 2-7. 10. A fibre reinforced structural element including a plurality of bolt fixtures, bolts or fittings for the fixation of said structural element to another structural element, said fibre reinforced structural element being produced in accordance with the method according to any of the points 1-7 and including a plurality of bolt fixtures, bolt assemblies or fitting assemblies produced in accordance with the method according to any of the points 8 or 9. 11. A bolt fixture, bolt assembly or fitting assembly for use in a fibre reinforced structural element being produced in accordance with the method according to any of the points 8 or 9.
