SE538233C2 - Splice system and method for providing a splice system - Google Patents

Abstract

SUMMARY This document describes a process for manufacturing a splice system comprising first and second parts (1, 2) formed of tra or trabased material. The parts are joined in a spirit-to-spirit relationship along a longitudinal direction (L) by means of a finger joint (3). A duct portion of the first part (1) has a plurality of parallel straight finger-like projections (31), which trade into and engage with a plurality of complementary parallel straight grooves (32) provided between projections (31) of the second part. A plane (Pt) comprising substantially the entire length of the habit protrusion tip (312), and / or a plane (Pn) comprising substantially the entire length of the habitual track bottom (321), extends at an angle (a) other than a right angle to the longitudinal direction (L).

Description

JOINT SYSTEM AND PROCEDURE FOR ESTABLISHING A JOINT SYSTEM Technical field The following description refers to a joint system and to a method for forming such a joint system.

The splicing system described he finds particular application in joining wood or wood-based materials, including laminated wood and wood-based materials, such as glue-type materials.

Background In many applications, it is Onskvart aft to join plank ends of pieces of timber, timber, boards, posts, beams and / or planks to form 6 'longer units.

A concept for such joining is as "finger joints" and is described in e.g. US3388020A and US3262723A.

In practice, the pieces of wood to be joined by means of a finger joint have a main direction which is approximately parallel to a fiber direction of the wood and a substantially rectangular cross-section. Each piece of wood thus has a first pair of parallel and opposite side surfaces and a second pair of parallel and opposite side surfaces. The side surfaces are essentially parallel to the main direction. The first and second pairs of surfaces are embedded at right angles to each other. Each piece of wood also has a face surface which is parallel to the cross section and perpendicular to the 'Dada pair of side surfaces.

A traditional finger joint is known as a camouflage sawtooth-like monster with alternating protrusions and spurs at one of the side surfaces, called the first side surface. Della monsters extend through the entire piece of wood perpendicular to the side surface. Seen from the adjacent side surface, ie. one of the other side surfaces, the finger joint is generally perceived as a straight joint extending perpendicularly through the piece of wood. 1 Conventional finger joints have projections and spurs that extend parallel to each other and transverse at right angles to two parallel side cradles in the timber or plank.

There is a general desire to further increase the hall strength of finger joints. A concept for increasing the hall strength is described in US3692340A. Yet another concept is described in US2003026955A.

Summary One purpose of the present description is to provide an improved joint for wood and wood-based materials.

The invention is defined by the appended independent claim. Embodiments are apparent from the dependent claims, in the following description and from the accompanying drawings.

According to one aspect, there is provided a method of making a splice system. The method comprises providing a first part formed of tra or trabased material and forming a plurality of parallel straight grooves, which run transversely over a duck portion of the first part, whereby a plurality of parallel straight finger-like projections are formed. The method further comprises forming the recesses so that a plane comprising substantially the entire length of each protrusion tip, or a plane comprising substantially the entire length of each recess bottom extends at an angle other than a right angle to the longitudinal direction.

The method comprises providing a second part formed of tra or trabased material, forming a plurality of parallel straight grooves, which run along a duct portion of the second part, whereby a plurality of parallel straight finger-like projections are formed, and joining the first and second parts by bringing the projections of the first part to trade in and engage with the spares of the second part and vice versa. In this method, the grooves of the second part can be formed so that a plane comprising substantially the entire length of each protrusion tip, or a plane comprising substantially the entire length of each groove bottom, extends at an angle other than a straight angle to the longitudinal direction. The method comprises forming a duck plane at the duck portion of the first and / or second part at an angle other than a different angle to the longitudinal direction and then forming the grooves in the duck plane. Such formation may include a splicing operation performed during a movement of the splicing tool in a direction parallel to the duck plane.

The spirit plane can be formed before the formation of the spades.

The method may further comprise providing the first part by arranging first and second laminated pieces of material so that the second piece of material extends further than the first piece of material with a length substantially corresponding to T * tan (a), where T is the thickness of the second piece of material, and then cutting the first part along a cutting plane which substantially tangents to a duck portion of the first part at a line directly adjacent the second part.

Consequently, the loss of material can be reduced by joining together 15 spirits of so-called glulam materials.

A longitudinal direction can be a direction with the main demand of the parts. For parts having a rectangular or square cross-section, the longitudinal direction may be parallel to the side surfaces of the parts.

A "trabased material" is to be understood as a material comprising trafiber. Such materials may have anisotropic half-strength properties, as would be the case where the material exhibits a major fiber direction which is substantially parallel to the longitudinal direction.

By reducing the angle of the plane (s) towards the longitudinal direction, the effective contact surface between the projections and the spade Okas can be achieved, which provides a more hall-fixed joint.

The invention is applicable both when joining together against wooden and gluing wooden material to provide beams, planks or posts which are longer than the individual pieces of material which form the beam or post.

The invention is also applicable to the joining of spirits of a piece of material from which a section has been cut away, which would be the case when removing, for example, a portion having a defect, such as a twig or crack or other weak point. Consequently, a piece of wood, boards of pieces of wood, post, beam or plank 6 can be provided which have a joint system described herein. The invention finds particular application in the joining of wooden and wooden-based materials to elongate structures, such as beams, posts, planks, ribs or strips, which have a main direction extending along the longitudinal direction.

In most applications, this means the plane (s) will extend at an angle other than a straight angle to at least one side surface of the parts, or to a pair of opposite side surfaces.

Brief Description of the Drawings Fig. 1 is a schematic perspective view of a pair of joined pieces 1, 2 of trabased material.

Fig. 2 is a schematic side view of the pair of joined pieces 1, 2 of trabased material in Fig. 1.

Fig. 3 is a schematic top view of a duck portion of a piece 1 of trabased material.

Fig. 4 is a schematic top view of a pair of duck portions 1, 2 in an almost joined condition.

Fig. 5 is a schematic perspective view of a pair of joined pieces 1 ', 2' of laminated material.

Fig. 6 is a schematic perspective view of a pair of joined pieces 1 ", 2" of laminated material.

Figs. 7a-7d schematically illustrate a method of making a finger joint.

Fig. 8 is a schematic side view of a laminated piece of material. Fig. 9 is a graph showing test results of embodiments according to the present description.

Detailed description 4 Fig. 1 is a schematic three-dimensional view of a pair of joined pieces of material 1, 2 joined together. Fig. 1 also illustrates the coordinate system which will be used in the description below.

As can be seen from Fig. 1, the material pieces 1, 2 have been joined together with a so-called finger joint 3. The material pieces 1, 2 have a respective main side surface 11a, lib; 21a, 21b and a respective side surface 12a, 12b; 22a, 22b.

The pieces of material 1, 2 are joined together to form a common part which extends along a longitudinal direction L.

The pieces of material can have a substantially rectangular or square cross-section, optionally with rounded corners. Other cross-sections are possible, such as circular, elliptical, prismatic, polygonal, etc., the cross-section may be substantially constant along the longitudinal direction L.

Referring to Fig. 2, it is noted that the joint 3 has a joint angle α which is less than 900 relative to the main side surface 11a, 21a.

Referring to Fig. 3, a duck portion of the first part 1 has a plurality of alternately arranged finger-like projections 31 and grooves 32. The projections 31 have a respective side surface 311, 313 and a tip surface 312. At the bottom of the habit groove 32 there is a spar bottom surface 321.

The projections 31 form parallel axes between which parallel grooves are formed.

The protrusions 31 can be formed so that all the protrusions extend substantially equally in the longitudinal direction L so that the tips or tip surfaces 312 define a common tip plane Pt.

The savings 32 can be substantially the same depth in the longitudinal direction L, so that the savings bottom surfaces 321 also define a common savings plan Pn.

In the embodiment shown in Fig. 3, the apex plane Pt and the saving plane Pn are substantially parallel and extend with a joint angle α relative to the main surface 11a, 21a (and the longitudinal direction L), which is less than 90 °. In addition, planes Pt, Pn are substantially perpendicular to the side surface 12a, 22a.

The joint angle α can be 80 ° or less, 70 ° or less, 60 ° or less, 50 °, 45 ° or less, 40 ° or less, or 30 ° or less towards the major surface 11a, 21a. In addition, the joint angle α may be 0 or more, 20 ° or more, 30 ° or more or 40 ° or more towards the major surface 11a, 21a.

In particular embodiments, the joint angle α may be in the order of 0-0, 0-0 or 0-700.

The projections 31 are further formed, which is conventional, with respect to the saving depth Dn, tip width Wt, saving bottom width Wn and side angle b.

Fig. 4 schematically illustrates the joining of a first 1 and a second 2 part tangent to the longitudinal direction L. In connection with the joining, an adhesive can be provided on the side surfaces 311, 313 of the axles and grooves and optionally also on the tip and bottom surfaces 312, 321.

The parts can be forced against each other while the glue is activated. Activation of the adhesive can be achieved by e.g. straining, heating or vibration.

Fig. 5 schematically illustrates the joining of a pair of laminated parts 1 ', 2'. In this embodiment, pieces of material 13a, 13b, 13c, 13d to be laminated have their laminated main surfaces facing each other. The finger joint 3 is provided so that the joint angle α extends at an angle to another at a right angle to the main surfaces of the material pieces 13a, 13b, 13c, 13d and at a right angle to the side surfaces of the material pieces 13a, 13b, 13c, 13d.

Fig. 6 schematically illustrates the joining of a pair of laminated parts 1 ", 2". In this embodiment, pieces of material 13a ', 13b', 13c ', 13d' to be laminated have their laminated main surfaces facing each other. The finger joint 3 is made so that the joint angle α is stacked at an angle to another at a right angle to the surfaces of the material pieces 13a ', 13b', 13c ', 13d' and at a right angle to the main surfaces of the material pieces 13a ', 13b', 13c '. , 13d '.

Referring to Figs. 7a-7d, a joint 3 described herein may be disassembled as follows.

As shown in Fig. 7a, a pair of parts 1, 2 are provided which are to be joined.

The parts 1, 2 may be in the form of relatively short pieces of material, e.g. in the order of 0.5-2 m in length or relatively long pieces of material, e.g. in the order of 2-5 m in length. As shown in Fig. 7b, a part of the duck portion is cut from habit part 1, 2 bait, so that the duck plane 30 is established, which have an angle α corresponding to the joint angle of the finger joint to be produced.

As shown in Fig. 7c, grooves 32 are then formed in the duck surfaces 30. The grooves can be formed by a cutting operation by means of a multi-edged cutting tool (not shown), which is caused to move along the duck plane, ie. linear along a path which forms the angle α relative to the longitudinal direction.

After the formation of the recesses, the line can be applied to all or parts of the side surfaces of the projections 31 and the recesses 32.

As shown in Fig. 7d, the parts 1,2 are pushed together along the longitudinal direction L and are forced against each other for at least a part of the time it takes for the glue to harden.

While the above method is applicable to both solid iva pieces of material (such as solid wood) and to laminated parts (such as glued), Fig. 8 schematically illustrates a method that can be used in the joining of laminated parts.

As mentioned earlier, habit laminated part can be formed of a plurality of pieces of material 13a, 13b, 13c, 13d. The pieces of material may be arranged so that a second piece of material 13b extends further along the longitudinal direction than a first piece of material 13a with a length E corresponding to about T * tan (a), where T is a thickness of the second piece of material 13b. If the laminated part comprises further pieces of material 13c, 13d, the habitual subsequent piece of material may thus be arranged to protrude past the foregoing in a manner similar to the second piece of material 13b.

The cutting operation discussed with respect to Fig. 7b above can then be performed along a plane tangential to cuts between the second side having the first part and the main side having the second part, so that essentially only triangular paths 14a, 14b, 14c, 14d are cut away.

The finger joint 3 can thus be formed as described with respect to Figs. 7c-7d.

With the present invention, the effective adhesive surface can be increased evenly with finger joints according to prior art having a perpendicular joint angle. Thus, the amount of glue used will increase. Referring to Fig. 9, the left pile represents a 900 splice plane according to the prior art. The middle stack represents a 60 ° joint plane which achieved a 13% increase in buoyancy with a 15% increase in the cost of adhesive. The right bar represents a 45 ° joint plane which achieved a 49% increase in buoyancy strength with a 41% increase in cost of adhesive. 8

Claims (15)

1. A joint system comprising: first and second members (1 , 2) formed of wood or wood basedmaterial; the members being joined in an end-to-end relationship along alongitudinal direction (L) by means of a finger joint (3); wherein an end portion of the first member (1) presents a plurality ofparallel straight finger-like projections (31), which enter and engage a pluralityof complementary parallel straight notches (32) provided between projections(31) on the second member (2); characterized in that a plane (Pt) comprising substantially the entire length of eachprojection tip (312), and/or a plane (Pn) comprising substantially the entirelength of each notch bottom (321), extends at an angle (a) other than a rightangle to the longitudinal direction (L).

2. The joint system as claimed in claim 1, wherein the plane (Pt,Pn) extends at right angle to one side face (12a, 12b, 22a, 22b).

3. The joint system as claimed in claim 1 or 2, wherein the plane(Pt, Pn) extends at an angle (a) of 80° or less, 70° or less, 60° or less, 50°,45° or less, 40° or less, or 30° or less, to the longitudinal direction (L).

4. The joint system as claimed in any one of the preceding claims,wherein the plane (Pt, Pn) extends at an angle (a) of 10° or more, 20° ormore, 30° or more or 40° or more, to the longitudinal direction (L).

5. The joint system as claimed in any one of the preceding claims,wherein the members (1, 2) have a major fiber direction which substantiallycoincides with the longitudinal direction (L). 11

6. The joint system as claimed in any one of the preceding claims,wherein the projections (31) are tapered in cross section as seen from themember (1) and outwardly along the Iongitudinal direction (L).

7. The joint system as claimed in any one of the preceding claims,wherein a glue or adhesive is applied to the surfaces (311, 313) of at leastparts of the projections (31) and/or notches (32).

8. The joint system as claimed in any one of the preceding claims,wherein at least one of the members (1, 2) is formed of solid wood.

9. The joint system as claimed in any one of the preceding claims,wherein at least one of the members (1, 2) is formed of at least two laminatedmaterial pieces (13a, 13b, 13c, 13d; 13a', 13b', 13c', 13d') with a laminationplane extending parallel to the Iongitudinal direction (L).

10.wherein the members (1, 2) present four major side faces, all of which being The joint system as claimed in any one of the preceding claims, substantially parallel with the Iongitudinal direction (L).

11.providing a first member (1) formed of wood or wood based material; A method of making a joint system, comprising: providing a second member (2) formed of wood or wood basedmaterial; forming a fingerjoint (3) comprising a plurality of parallel, straightnotches (32), which run across an end portion of the first member (1),whereby a plurality of parallel straight finger-like projections (31)are formed,and joining the first and second members end-to-end along a Iongitudinaldirection by means of the fingerjoint (3); characterized inthat the notches are formed such that a plane comprising substantially theentire length of each finger tip, and/or a plane comprising substantially the 12 entire length of each notch bottom, extends at an angle other than a rightangle to the longitudinal direction (L).

12. The method as claimed in claim 11, further comprising: forming a plurality of parallel, straight notches, which run across an endportion of the second member, whereby a plurality of parallel straight finger-like projections are formed, and joining the first and second members by causing the projections of thefirst member to enter and engage the notches of the second member and viceversa, whereby the notches of the second member are formed such that aplane comprising substantially the entire length of each finger tip, or a planecomprising substantially the entire length of each notch bottom, extends at anangle other than a right angle to at least one side face of the second member.

13. The method as claimed in claim 11 or 12, comprising: forming an end plane at the end portion of the first and/or secondmember, at an angle other than a right angle to at least one side face of themember and subsequently forming the notches in the end plane.

14. The method as claimed in claim 13, wherein the end plane isformed prior to the forming of the notches.

15. The method as claimed in any one of claims 11-14, furthercomprising: providing the first member by arranging first and second laminatedmaterial pieces (13a, 13b), such that the second material piece (13b) extendsfurther than the first material piece (13a) by a length (E) substantiallycorresponding to T * tan(a), where T is the thickness of the second materialpiece (13b), and subsequently cutting the first member along a cutting plane (Pc) whichsubstantially tangents an end part of the first member at a line directlyadjacent the second member.