EP0819200B1

EP0819200B1 - A series of fittings for joining i or u-beams or other beam cross sections

Info

Publication number: EP0819200B1
Application number: EP96909986A
Authority: EP
Inventors: Henrik Thorning
Original assignee: Fiberline Composites AS
Current assignee: Fiberline Composites AS
Priority date: 1995-04-03
Filing date: 1996-04-03
Publication date: 2001-07-11
Anticipated expiration: 2016-04-03
Also published as: CA2217208A1; EP0819200A1; NO974552D0; DE69613824D1; ES2158305T3; DK36895A; PT819200E; AU5332596A; DK0819200T3; NO974552L; ATE203076T1; NO318382B1; DE69613824T2; WO1996031667A1

Abstract

A series of fittings is provided for joining I or U-beams of composite materials for bearing structures in form of frames, lattice structures etc. Each joint between adjacent beams is formed by particular fittings of a U-shaped profile in cross section. The back of the U is of a width corresponding to the inner width between the flanges of the I or the U-beams. The flanges of these fittings present almost the same outer width as the inner width of the flanges of the I or the U-beams. When seen in the longitudinal direction, the particular fitting of each beam joint is formed by two members together forming the same angle as the adjacent beams of the beam joint. The resulting joining of structures is very fast compared to conventional joining of structures, and it presents nevertheless a high strength.

Description

Technical Field

The invention relates to joint structure for a bearing structure, said joint structure comprising

a) profile members, such as for instance I and U-profiles, of fibre-reinforced plastics, said profile members having a profile body and two profile flanges protruding from the body so as to form a longitudinal channel defined by inner surfaces of said profile body and said profile flanges,

b) a joining fitting for joining said profile members at a predetermined angle and having a fitting body and two fitting flanges protruding from the fitting body, outer surfaces of said fitting body and said fitting flanges defining a contour substantially corresponding to the channel of the profile members, and

c) fastening means for securing the joining fitting to the profile members, said joining fitting comprising portions mutually defining said predetermined angle and being received in a respective channel of said profile members, the outer body surface of said joining fitting abutting the inner body surface of the profile members,

The profile members of the joint structure may be I or U-profiles or profiles with other cross sections and the joint structure can be used within the chemical industry, offshore, ship construction, water purifying plants, buildings for EMC-test housings, masts for railways, airports etc.

Background Art

US-A-5,210,990 discloses wood construction members in form of wood panels made of wood composite material or a replacement of wood panels made of solid wood. This publication discloses a way of joining construction members which are perpendicular to one another by means of a box--shaped splice block.

DE-A-847,068 discloses a joining method by means of wedges being wedged in between the joining fittings and the metal profiles. Such a joining cannot be used for transferring a large moment load because the wedges involve a point load and are difficult to position in practice. The invention known from this publication is based on the fact that the material is ductile, which is not characteristic of fibre-reinforced plastic materials, a so-called composite material.

WO 85/01307, which is the closest prior art and on which the preamble to claim 1 is based, discloses a joint structure for joining two steel I-profile members and comprising a U-shaped fitting or fishplate arranged in the channels of each of the profile members. The body of each fitting abuts the body of the I-profile members. It is, however, not mentioned or indicated anywhere in the description that the flanges of the fittings tightly engage the adjacent flanges of the I-profile members. On the contrary Figures 2,10 and 11 illustrate that at least one of the flanges of the fitting is spaced apart from the adjacent flange of the profile member. Without said tight engagement between the flanges of the fitting and the flanges of the profile members, transverse forces acting transversely between the flanges can only be transferred between the fitting and the profile members via the bodies thereof and not via the flanges thereof.

Brief Description of the Invention.

The object of the present invention is to provide a joint structure as stated in the preamble to claim 1 which remedies the drawbacks of known joint structures and allow for fast assembling of bearing structures compared to conventional assembling of steel structures, while great strength in the bearing structure is still obtained, especially in the joints.

This object is according to the invention obtained in that the outer flange surfaces of the joining fitting tightly engage the inner flange surfaces of the profile members. Thus the flanges of the particular fittings engage the flanges of the profiles when their bodies engage the bodies of the profiles such that the optimum surface of contact is obtained and such that the strength of the flanges of one profile is transferred to the flanges on the fittings and subsequently transferred to the flanges of the other profile, and the strength of the body of one profile is transferred to the body of the fittings and subsequently to the body of the other profile when the fittings have been secured to the profiles by means of fastening means such as bolts, pin, rivets etc. or glue or a combination thereof.

The fittings can be attached to the composite profiles by way of bolting or gluing or a combination thereof. The resulting strength is high, because the fittings cover the largest possible portion of the surface of the profile and accordingly distribute the forces across the largest possible area. The latter presents a decisive factor in connection with profiles made of a composite material, because the capacity of such profiles or beams for resisting point loads is poor.

The cross sectional shape of the fittings is adapted to the shape of the profiles so as thereby to obtain a maximum contact surface for transferring the bending and the tractive/compressive forces, the shearing stress, the torsional and the moment forces about both the weak and the strong axis of the profile. In addition, the contact surface reduces the point loads and provides self-supporting properties during the mounting without the use of wedges etc. The shape of the fittings solves the problem of the expressed difference between the tensile and bending strength versus the shearing stress. Finally, in connection with a glue joint, the shape of the fittings ensure that the forces are transferred by means of a shearing stress either onto the body or onto the flanges no matter which direction the fittings are subjected to a load. The latter is essential to glue joints because such joints can only absorb shearing stresses.

As stated in claim 2, the body and the flanges of the fitting are of differing thicknesses. A demand often exists for a larger thickness in the flanges than in the body due to the prevailing forces, but the opposite can sometimes be the case.

As stated in claim 3, the fitting may be perforated in a pattern not involving a reduction of the strength about the bolt openings. The purpose of using a perforation in connection with the adhesive joint is that both a mechanical and a chemical adhering are obtained between the fittings and the profiles, whereby it is possible to visually check the position of the glue. The perforation is used in connection with metals because the weight of the structure is thereby reduced. Finally, the perforation allows the use of self-cutting screws in case it is desired. The bolts used may be ordinary machine bolts, carriage bolts, unbracco bolts with a countersunk head, as well as self-cutting screws, button-head rivets, ordinary rivets etc. Here it is possible merely to use a hand drill, and the joinings can typically be carried out in less than 5 minutes.

As stated in claim 4, depending on the use many different types of materials and material combinations may be used for the fitting such as fibre-reinforced plastics in form of thermoset or thermoplast, and metal. Examples of a composite material in form of fibre-reinforced thermoset are for instance polyesters, vinylesters, bisphenoles, epoxy, phenoles, polyurethane etc. Examples of a composite material in form of fibre-reinforced thermoplast are polypropylene, polyethylene, acrylnitrilo-butadiene-styrene terpolymer, polyamide, polyethylene terephthalate and polyurethane. Examples of metals are steel, stainless steel, zinc, copper, magnesium etc.

When the fittings are made of composite materials which are anisotropic materials, the fibre orientation is often +/- 45°, 90°, 0° in order to obtain an optimum shearing stress and torsional rigidity. Such fittings of composite materials are moulded of thermoset or shaped from thermoplast.

As stated in claim 5, the fitting is made of a composite material with a tear-off tape or tissue or a glue sheet in the surfaces facing the profiles members in order to improve a glue joint. It is obvious, that such a glue joint can be supplemented with another joint as stated above, such as a bolt joint.

As stated in claim 6, the profiles and the fitting may be made of the same material, which is often very advantageous with respect to the strength, the resilience, the resistance, the isolation, the thermal expansion etc.

As stated in claim 7, the fitting may be manufactured either by way of pultrusion, injection moulding, cold pressing, hot pressing or by hand lay up.

As stated in claim 8, the fitting may for instance by way of moulding be provided with drilling instructions for drilling holes for the bolt joints or rivet joints.

Contrary to the disclosure of WO 85/01307 the fitting may engage the profiles on the entire surface of the fitting facing the profiles, the ends of the profiles at the point os contact interengaging such that the compressive force in the profiles ca be transferred by the direct contact between the surfaces of the profiles and such that the profiles have a continuous appearance in the entire joint.

Brief Description of the Drawings.

The invention is explained in greater detail below with reference to the accompanying drawings, in which

Fig. 1 illustrates an I-beam lattice structure of composite material,

Fig. 2 is a diagrammatic view of an example of a series of fittings to be used by the lattice structure of Fig. 1,

Fig. 3a illustrates a plane metal blank for the manufacture of an inner corner fitting to be used at one of the four rectangular corners of Fig. 1, as shown at the angle between the I-

beams

1 and 2 of Fig. 2,

Fig. 3b illustrates a corresponding plane blank as in Fig. 3a, but made of a thermoplastic material, and shown before it is bent into a completed rectangular inner corner fitting,

Figs. 4a, 4b and 4c illustrate an inner corner fitting ready-made from the blank of Fig. 3b, or a corresponding corner fitting made of cast thermoplast, Fig. 5a being a perspective view thereof,

Figs. 4d, 4e and 4f illustrate half the inner rectangular corner fitting shown in 4a, 4b and 4c which is to be used for half an I-beam structure or a T-beam structure, Fig. 5b being a perspective view of the use said T-beam structure,

Fig. 5a is a perspective view of the joining of two I-beams not forming a corner by means of the corner joint of Figs. 4a, 4b and 4c,

Fig. 5b is a perspective view of the joining of two T-beams with the corner fitting of Figs. 4d, 4e and 4f,

Fig. 5c is a perspective and an exploded view of the joint between two I-beams not forming a corner, said joint using two of the inner corner fittings of Figs. 4a, 4b and 4c as well as a 0° fitting as shown in Figs. 7a and 7b,

Figs. 6a, 6b and 6c illustrate an outer corner fitting (270°),

Figs. 7a and 7b illustrate an 0° fitting,

Fig. 7c is a perspective view of the 0° fitting of Figs. 7a and 7b arranged in I-beams of composite material and used for joining two such I-beams,

Fig. 7d is a perspective and an exploded view of the joining of two I-beams of composite material by means of two 0° fittings as shown in Figs. 7a and 7b,

Figs. 8a, 8b and 8c illustrate a 45° fitting,

Fig. 8d is a perspective and an exploded view of a joint used in situ in the middle of the lowermost I-beam 1 of Fig. 1 and between said I-beam 1 and the two adjacent I-

beams

6, 7 forming 45° to their respective sides of the above first I-beam 1,

Figs. 9a, 9b and 9c illustrate a 135° inner fitting,

Fig. 9d is a perspective view of the 135° joint between two I-beams of composite material by means of the inner fitting of Figs. 9a, 9b and 9c,

Figs. 10a and 10b illustrate the joint between two I-beams forming an angle of 135° with one another, but in a plane perpendicular to the joining plane of Fig. 9d, by means of a fitting moulded of thermoset,

Figs. 10c and 10d illustrate the joint between two T-beams forming an angle of 135° with one another like in Figs. 10a and 10b by means of a fitting moulding of thermoset,

Fig. 11a is a perspective view of the joint between two I-beams of composite material, which are in continuation of one another (0°) by means of two fittings, which together fittingly follow the body and flanges of the I-beams,

Fig. 11b is a perspective view of a corresponding joint as in Fig. 11a, but where the I-beams are perpendicular to one another and form a corner,

Fig. 11c is a perspective view of the joining of two T-beams arranged perpendicular to one another and forming a corner by means of two fittings, which together fittingly follow the body and flange of said T-beams,

Fig. 12 is a perspective view of the joint between two hollow H-profile beams in continuation of one another (0°) by means of corresponding fittings as in Fig. 11a, and

Figs. 13a and 13b illustrate a 45° joining of a through profile and an adjacent T- profile, and Figs. 14a and 14b illustrate a 90° joining of a through profile and an adjacent I-profile.

Fig. 1 illustrates a lattice structure of I-beams of composite material. In the Figure, the individual beams 1 to 7 are shaped as shown, the bodies of the beams being indicated by means of dotted lines. A sectional view along the line A-A of Fig. 1 illustrates the cross section of the beam. The illustrated lattice structure is 1.5 m in any direction. As shown, the

beams

6 and 7 form an angle of 90°, and together with the beam 1 they form angles of 45° to their respective sides.

Fig. 2 is a diagrammatic view of the individual types of fittings and their use in the lattice structure of Fig. 1.

Fig. 3a illustrates a plane rectangular metal blank with a perforated pattern, said metal blank being intended for the manufacture of a fitting for a joint structure according to the invention.

Notches

10, 11, 12, 13 are punched out from the

longitudinal edges

14, 15. These-notches form angles of 45° with a central line 18 parallel to the short edges 16, 17.

The metal blank of fig. 3a comprises bending

lines

19, 20 parallel to the longitudinal edges and extending through the intersection of the

notches

10, 11, 12, 13 with the central line 18.

A 90° bending along the bending lines 19, 20 results in a profile of a U-shaped cross section, said profile subsequently being bent 90° around the central line 18. Then the

edges

10 and 11 are welded together with the edges 12 and 13 which results in an inner corner joint to be used at one of the four rectangular corners, such as in the corner between the I-

beams

1 and 2 of Fig 1.

Fig. 3b illustrates a corresponding plane blank as in Fig. 3a, but made of a thermoplastic material, and shown before it is bent into a completed rectangular inner corner fitting, The mating parts of Fig. 3a and Fig. 3b are provided with the same reference numerals. It should be noted that no notches are punched out in Fig. 3b like in Fig. 3a. Instead,

slots

21, 22 are provided parallel to the short edges 16, 17, said slots projecting from the long edges until the bending lines 19, 20. When the thermoplast material of Fig. 3b is bent about a line coinciding with the

lines

21, 22, the exceeding portions of the material at the flanges overlap one another and melt together due to the heat supplied during the moulding process. It is obvious that the blank shown in Fig. 3b of thermoplastic material can also be provided with a perforated pattern as shown in connection with the the metal blank of Fig. 3a.

Figs. 4a, 4b and 4c illustrate an inner corner fitting ready-made from the blank of Fig. 3b. This fitting can also be a corner fitting moulded of thermoset.

Figs. 4d, 4e and 4f illustrate half the inner rectangular corner fitting shown in Figs. 4a, 4b and 4c. This fitting comprises thus only one flange and half the body.

Fig. 5a is a perspective view of the joining of two I-

beams

30 and 31 not forming a corner by means of the corner fitting of Figs. 4a, 4b and 4c. This corner fitting is designated 32 in Fig. 5a.

Fig. 5b is a perspective view of the joining of two T-

beams

33 and 34 by means of a corner fitting 35 of the type shown in Figs. 4d, 4e and 4f.

Fig. 5c is a perspective and an exploded view of the joint between two I-

beams

36 and 37. The I-beam 37 is at the end facing the I-beam 36 provided with a nose 45. This nose results from further portions of the flanges of the I-beam being removed in such a manner that the body of the I-beam no longer projects so as to enter between the flanges on the I-beam 36. This is not a particular object of the invention, but it serves to reinforce the joining additionally. Two corner fittings 32 as shown in Fig. 5a as well as an 0° fitting 38 are used for the joint. All the members are made of the same type of composite material, and the joining is performed by way of gluing followed by bolting as indicated by the bolts 39 and nuts 40 shown.

Figs. 6a, 6b and 6c illustrate an outer corner fitting 41, i.e. the bodies 42 and 43 of the two parts of the fitting form an angle about a "bending line" 44. This fitting can be manufactured directly by moulding of thermoset. Then no actual bending is to be performed about the line 44.

Figs. 7a and 7b illustrate a 0° fitting 38 used in the middle at the top of Fig. 2 or Fig. 1, the same type of fitting being used on the inner side and the outer side for interconnecting the I-profiles of Fig. 1 in the middle. Fig. 7c is a perspective view of the 0° fitting of Figs. 7a and 7b arranged in I-beams of composite material for interconnecting two such I-beams. Correspondingly, Fig. 7d is a perspective and an exploded view of the joining of I-beams of composite material by means of two 0° fittings as shown in Figs. 7a and 7b.

Figs. 8a, 8b and 8c illustrate a 45° fitting, and Fig. 8d is a perspective and an exploded view of a joint between three I-beams by means of two 45° fittings and a 90° fitting as well as a 0° fitting. This joint can for instance be the joint shown in the middle of the I-beam of Fig. 1, where said beam meets the two I-

beams

6 and 7. Therefore the I-beams of Fig. 8d are designated in the same manner as the I-beams at the location in question in Fig. 1. The joining is performed by means of a rectangular fitting 32, two 45° fittings 50 and a 0° fitting 38. All these fittings can for instance be made of a composite material of the same type, and the fittings can either be moulded of thermoset or made of thermoplast. The fittings fit tightly in the I-profiles in the manner described in claim 1. The joining can be performed as a glue joining, and in order to improve the glue joining the fittings can be provided with tear-off tape ensuring that the glued surfaces are kept clean. Then the joint can be further reinforced by means of the screws 39 and nuts 40 shown. As an alternative, the fittings can be provided with a glue sheet in such a manner that after the tearing off of the sheet the fittings comprise an uncovered glue surface on the bodies and flanges facing the I-beams. For the drilling of holes for the screws 39, this embodiment as well as all the other shown and described embodiments can be provided with drilling instructions in form of small recesses in the composite material of the fittings at the locations where said holes are to be manufactured.

Figs. 9a, 9b and 9c illustrate a 135° inner fitting 60, Fig. 9d being a perspective view of said inner fitting. This fitting serves to join the two illustrated I-beams 61 and 62. On the opposite side of the joint of Fig. 9d it is, of course, possible to attach a second fitting following the body and the flanges of the I-beams in a corresponding manner.

Figs. 10a and 10b illustrate the joining of two I-

beams

71 and 72 by means of a fitting 70 in such a manner that here the beams form an angle of 135°, but in a plane perpendicular to the joining plane of Fig. 9d. The illustrated fitting 70 is preferably manufactured by way of moulding of thermoset. Here too a corresponding fitting is provided on the opposite side of the joint of the I-

beams

71, 72.

Figs. 10c and 10d illustrate the joining of two T-

beams

81 and 82 by means of a fitting 80 essentially corresponding to half the fitting 70 of Figs. 10a and 10b. This fitting is also preferably moulded of thermoset.

Fig. 11a is a perspective view of the joining of two I-beams of composite material. These two I-

beams

91 and 100, respectively, are arranged in continuation of one another, and they are joined by means of two identical fittings 90 which together fittingly follow the body and flanges of the beams, said two fittings being in contact in the line of symmetry of the flanges of the

beams

91, 92.

Fig. 11b is a perspective view of a joining like the joining of Fig. 11a, but whereby I-

beams

101 and 102 are perpendicular to one another and form a corner. In this case the inner corner fitting 103 differs from the outer corner fitting 104 in the manner illustrated.

Fig. 11c is a perspective view of the joining of two T-beams 111 and 112 arranged perpendicular to one another and forming a corner by means of two

fittings

113 and 114, which together fittingly follow the body and the flange of the T-beams.

Fig. 12 is a perspective view of the joining of two particular profiles, viz. two hollow H-profile beams 121 and 122 by means of corresponding fittings 90 shown in Fig. 11a.

Fig. 13 illustrates the joining of a through T-profile 131 and an adjacent T-profile 132. This joining is performed by means of a fitting 80 of the type shown in Figs. 10c and 10d, and such a fitting 80 is preferably arranged on both sides of the T-profiles.

Fig. 14 illustrates a 90° joint between a through I-profile 141 and an adjacent I-profile 142. This joint is provided by means of a particularly moulded fitting 140 preferably moulded of thermoset. This fitting 140 comprises a base member 143 and two

U-shaped profile members

144 and 145 interspaced a distance corresponding to the body of the vertical I-profile 142. This fitting is attached to the I-profiles in such a manner that initially the fitting is pushed downwards over the vertical I-profile 143 whereafter the horizontal through I-profile 141 is placed on the base member 143 which in turn is then attached to the horizontal through I-profile 141 by means of bolt connections optionally not until the joining has been performed in advance by means of gluing.

Claims

Joint structure for a bearing structure, said joint structure comprising

a) profile members (1-7;30,31;36,37;61,62; 71,72; 91,92;101,102; 121,122), such as for instance I and U-profiles, of fibre-reinforced plastics, said profile members having a profile body and two profile flanges protruding from the body so as to form a longitudinal channel defined by inner surfaces of said profile body and said profile flanges,

b) a joining fitting (32;41;46;50;60;70,90;103;104;113,114) for joining said profile members at a predetermined angle and having a fitting body and two fitting flanges protruding from the fitting body, outer surfaces of said fitting body and said fitting flanges defining a contour substantially corresponding to the channel of the profile members, and

c) fastening means (39,40) for securing the joining fitting to the profile members, said joining fitting comprising portions mutually defining said predetermined angle and being received in a respective channel of said profile members, the outer body surface of said joining fitting abutting the inner body surface of the profile members,

characterised in that
the outer flange surfaces of the joining fitting tightly engage the inner flange surfaces of the profile members.
Joint structure as claimed in claim 1, characterised in that the body and the flanges of the fitting (32;41;46;50;60;70;90;103;104,113,114) are of differing thicknesses.
Joint structure fittings as claimed in claim 1 or 2, characterised in that the fitting (32;41;46;50;60;70;90;103;104,113,114) is perforated in a pattern.
Joint structure as claimed in any of the preceding claims, characterised in that the fitting (32;41;46;50;60;70;90;103;104,113,114) is made of a material or a material combinations selected from the group including fibre-reinforced plastics in form of thermosetting or thermoplastic, and metal.
Joint structure as claimed in any of the preceding claims, characterised in that the fitting (32;41;46;50;60;70;90;103;104,113,114) is made of a composite material with a tear-off tape or tissue or a glue sheet in the surface facing the profile members in order to improve a glue joint.
Joint structure as claimed in any of the preceding claims, characterised in that the profile members (1-7;30;31;36,37;61,62;71, 72;91;101, 102;121;122) and the fitting (32;41;46;50;60;70;90;103;104,113,114) are made of the same material in order to obtain the same material properties with respect to strength, resilience, resistance, insulation, thermal expansion etc.
Joint structure as claimed in any of the preceding claims, characterised in that the fitting (32;41;46;50;60;70;90;103;104,113,114) is manufactured by a process selected from the group including pultrusion, injection moulding, cold pressing, hot pressing and hand lay up.
Joint structure as claimed in any of the preceding claims, characterised in that the fitting (32;41;46;50;60;70;90;103;104,113,114) is provided with drilling instructions for drilling holes for bolt connections (39,40) or rivet connections.