GB2195000A

GB2195000A - Frame joint

Info

Publication number: GB2195000A
Application number: GB08616782A
Authority: GB
Inventors: Torge Taras Ugur; Ivo Alexander Ugur
Original assignee: INTEC
Current assignee: INTEC
Priority date: 1986-07-10
Filing date: 1986-07-10
Publication date: 1988-03-23
Anticipated expiration: 2006-07-10
Also published as: GB2195000B; GB8616782D0

Abstract

A mitred corner joint of a frame comprises aligned grooves in abutting faces which extend less than the length of these faces, and a rabbet tongue 9 is driven into said grooves. The leading edge of the tongue 9 is provided with protrusions 7 adapted to spike into the blind end of the grooves. The tongue sides are preferably also provided with ridges to coact with the wall of the groove. An adhesive may also be used. Voids in the joint may be filled with a curable resinous material or a settable or extrudable plastics material. <IMAGE>

Description

SPECIFICATION Jointing a pair of frame members The invention refers to a method and to means for jointing frame members and to mitred joints. The jointing of such members is conventionally securely effected by employing hooked clasps or dowels. If applied across the abutment or the mitre and held within the pair of members, these dowels of either wood, plastic or other nailable or incisible material become concealed when viewed from the front, particularly when, as in the case of mitred frames, the dowels are inserted in the direction of the plane of the frame along grooves; the cross section of the dowels is then of substantially the same complex shape as that of the hooked clasp or dowel that is slidably inserted.For insertion of these channel- or dowel-shaped slides the kerfs or grooves of known dowelling arrangements must be pre-cut in the abutting faces of the mitre prior to placing the frame members into the angularly abutting position. The clasping is then effected by the bent-up sides, else, the keyhole or dovetail sections of the dowel, therewith to secure the frame members in hooklike fashion. The extent of the dowels' hooking sections will however, at most, be equal to the length of the mitre line. The bentup height, or the corresponding keyhold resp.

dovetail shape of the flanges of the dowels that are normally inserted centrally into the grooved abutting members of the mitre is also limited, say, to a mere quarter of the members' thickness. Furthermore, the glue or contact area of keyhole- or dovetail-shaped dowels is limited by the natural balanced proportions of width, length, and cross section necessary in shaping said dowels, also their thickness is limiting the number of such dowels in a side-by-side relationship within each mitre joint, resulting in a reduced contacting surface of the frame members' area at their abutment.

The invention aims at obviating the drawbacks of these jointing methods and arrangements, especially when applied to frame corner constructions. The invention also aims generally to improve the joining and securing of abutting members made of wood or other nailable or incisible materials, by means of rabbet tongues that are inserted into the likesized kerfs or grooves in both members to become concealed when viewed from the front of the joint, or frame.

According to the invention, the kerfs or grooves in the abutting members are cut to a lesser extent than the length of the abutting faces, the tip end or leading edge of the correspondingly shorter rabbet tongue provided with protrusions adapted to coact with or to spike into the now blind end of said grooves to secure the joining.

According to a characteristic of the invention, when applied to a frame mitre joint with rabbet tongues inserted in the direction of the frame into the abutting, grooved members, these grooves are cut into the abutment faces and extend angularly towards and open-out at the frame members' side edges. An inventive aspect of this arrangement has the said grooves cut at right angles to the direction of the plane of the mitre, opening-out at the frame members' side edge.

In all such joints between pairs of grooved frame members, according to the invention, the inserted rabbet tongues are of wood, plastic, else, of metal. If made of wood, at least two protrusions jut out from the tongue's tip, else, at least two spikes are in the leading edge of the rabbet tongue, these spikes according to invention, diverging relative to said edge and/or one or both flat surface of the rabbet tongue comprise divergent ridges; if on the other hand, made of flat metal stampings, according to the invention, these have a serrated tip end and/or divergent straight embossings or opened-out divergent ridges.

In the method of manufacture frames' mitre joints, according to the invention, a pair of frame members are placed at an angularly abutting position, their abutting faces either pre-cut or post-cut across its mitre by one or more sawn kerfs in the plane of the frame, inserting one or more flat or ridged rabbet tongues of the same, substantially triangular shape as that of the cut kerf and, after internally meeting the opposing members and for friendly homing the rabbet tongues, the spikes at the rabbet tongues' leading edge are then driven home into the frame material to effect a concealed and secure dowelled joint.

Prior to and/or after this insertion and spiking, according to the method of the invention, adhesive is applied to, or settable resinous plastic material is pressure injected, therewith to bond, and to fill any voids between, the abutting frame members and/or between the kerfs and the rabbet tongues, finally to secure the mitre shape.

A type of the prior art and examples of the invention are depicted in the accompanying drawings.

Figure 1 gives a plan and front views of a known dowelled mitre joint.

Figure 2 gives a plan view of a corner construction, its angularly abutting members jointed by an embedded arrowhead-shaped rabbet tongue with its two protrusions.

Figure 3 gives a plan view of a mitre joint, its abutting frame members secured by an embedded triangular, flat-topped rabbet tongue with two diverging spikes in its leading edge.

Figure 4 gives a plan view of a corner construction, the abutting members secured by a substantially round, embedded rabbet disc comprising two radially protruding spikes.

Figure 5 gives a plan view of a joint between two abutting, aligned members, secured by a pair of opposingly embedded triangular and spiked rabbet tongues.

Figure 6 gives a perspective view of a triangular-shaped rabbet tongue with four diverging spikes in the leading edge and, atop, with a pair of ridges diverging in the same sense.

Figure 7 gives a perspective view of a triangular metallic rabbet tongue its hypotenuse with four stamped-out teeth and with four also bent-out ridges, these diverging towards the hypotenuse.

Figure 8 gives plan and side views of a frame, each of the mitres of its four corners secured by a pair of rabbet tongues according to Fig. 6.

Figure 9 gives a perspective view of a frame's corner with a groove cut across the mitre line; also shown is the perspective view of a series of aligned rabbet tongues, prior to their insertion and subsequent separation as triangular tongues, each with a diverging pair of flat spikes partly inserted into the tongue surface.

Figure 10 gives a perspective view of a frame's corner with a series of narrow grooves sawn across its mitre line; also shown is the perspective view of superimposed triangular metal sheets, each with its integral serrated leading hypotenuse and bentopen diverging ridges that are stamped-out to one side.

Where appropriate, the same references are given in all the figures.

In conventional mitre joints, as depicted in Fig. 1, prior to jointing, the surfaces of the two wooden or like members 1 & 2 of a frame are dovetail- or keyhole-grooved in the direction of the frame. These grooves, upon abutting the members, will come into alignment, thus, adapted to accept a substantially flat dowel 4 that is provided with flanged sides and with recessed front and pointed rear edges, this shaped dowel upon being slid into the groove, filling the space created by the aligned grooves, its flanges "hooking" thus securing, the members 1,2 in the mitre position. The length b of the mitre line and the lengths a of the flanged sides are equal; also, depending on the dowel's thickness, the size c of the flanges keying the members is restricted, say, to a quarter of the thickness d of the members.

Fig. 2 shows one novel corner construction for the members 1 & 2 of a frame. Prior, or after, abutting these members, a straight cut is effected, or a kerf is sawn, obtusely meeting the eventual mitre line b so that, upon abutting the members, an aligned arrowhead groove obtains adapted to accept the correspondingly shaped arrowhead rabbet tongue inserted in the direction of the frame. On driving the rabbet tongue home, the component force by the obtusely inclined leading edges a of the "winged" tongue achieves the secure mitre joint, incidentally, with the lengths a coacting with the base line of the groove in the members 1,2 becoming greater than the mitre line b.

In the stead of obtusely cut grooves in the frame members 1 & 2, according to another novel joint arrangement of the mitre Fig. 3, a straight cut, preferably at right angles across the mitre line b, is effected after abutting the said members, opening out at the frame sides.

The corresponding triangular rabbet tongue is here provided at its leading edge, the hypotenuse, with a pair of diverging spikes, or like toothed protrusions of a certain extension e, these setting up component forces upon driving home the rabbet tongue when inserted into the groove and spiking into the base line of the groove in the members 1,2 thereby aiding in securing the mitre joint.

An alternative novel mitre joint arrangement is shown in Fig. 4. It employs, after abutting the frame members 1 & 2, a circularly cut groove opening out at the frame sides, and its disc-shaped rabbet tongue is provided with a pair of radially extending, thus, diverging spikes with respect to the mitre line b, these spikes also setting up the component forces for securing the mitre joint upon driving the disc home while spiking to their extent e into the frame members 1,2.

According to an aspect of the invention, the jointing of nailable or incisible members need not be in a corner configuration as, likewise, linearly abutting members 1 & 2 can be joined, as is depicted in Fig. 5. The end faces of each member, prior to abutting same, are cut straight at an angle to the face line b, the cuts opening-out to both sides of the members, so as to obtain aligned triangular grooves when in the joining position. The correspondingly triangular rabbet tongues, instead at their long, or hypotenuse, edge have now the divergent spikes, or protrusions, at the side edges of the tongue which, on driving the rabbet tongues home, by the then set-up component forces will again achieve the secure alignment of the abutting members 1,2, spiking into the grooves' base lines now inclined with respect to face b.

Modifications to the basic, flat rabbet tongue shapes, especially the triangular ones 9 applicable to Fig. 3, are shown in the perspective views of Figs. 6 and 7. These rabbet tongues are made of wood, plastic or like, else, of metal stampings. Their leading edge, or hypoyenuse, is provided with 4 diverging spikes 5, else with serrations shaped as toothed protrusions 6, and their surface with also diverging hard inserted ridges 7, which incidentally can extend to form the said spikes; else, they can be provided with opening-out stamped ridges 8; these latter ridges can also be mere embossings.

The plan and side views of Fig. 8 depict a square frame with mitred members 1,2 of a thickness d permitting the spaced cutting of two grooves in the direction of the plan of the frame across each mitre line b, and the subsequent insertion of pairs of rabbet tongues 9.

These rabbet tongues are driven-in in the direction of the arrows f when on homing, their spikes in the leading edge will enter the base line of said grooves, thereby 'stapling', thus, securing the corner construction at the mitres.

Fig. 9 is a similar perspective view as is Fig. 8. This frame's corner construction accepts a single triangular rabbet tongue 9 in the groove which is cut straight across the mitre line b. In practice, this tongue is a lath tightly fitting the said groove. At distances marked by g, equalling the lengths of the tongue hypotenuse, its surface carries pairs of partly inserted combined spikes & ridges 7,8.

After driving-in, and homing, the lath in the direction of arrow f, its marking line g coinciding with the mitre line b, the overhanging parts of the lath is sawn off to obtain the desired, now triangularly shaped rabbet tongue insert for the mitre.

Fig. 10 is a similar perspective view as shown in Figs. 8 & 9. Instead of two or one wooden or like rabbet tongues for the frame's mitres, the relatively thick frame members 1,2 have here five cuts sawn straight across the mitre line b, to accept as rabbet tongues the triangular metal stampings 9 shown in superimposed fashion, all tightly fitting their cuts.

The tongues' leading edges are divergingly toothed; furthermore divergent, stamped-open ridges, as in Fig. 7, are provided and, for insertion in the direction of arrow f, all the ridges 8 of these tongues 9 extend to one side.

Like the divergent spikes that are coacting with the grooves' base line also the divergent ridges that coact with the grooves' wall will, when inserting and driving home the rabbet tongues, by the then set-up component forces on the members 1,2, effect a closing pull on the two abutting members therewith ensuring the jointing, especially of mitre arrangements.

In order further to effect secure joints, prior to the insertion of the rabbet tongues into grooved members, these and the abutting faces are coated with glue or an adhesive.

Additionally, it is preferred that, after the fitt ing and homing of the rabbet tongues, curable fillers, like resinous thermoplastics, are pres sure-injected to fill remaining voids and to firmly bond the structure.

Front viewed mitred frames that are provided with the inserted rabbet tongues of the invention will conceal these inserts; only at the frame side will the tongue edge become visible.

Claims

1. Joint between a pair of members made of wood or of another nailable or incisable material, in particular corner constructions of frames with members abutting one another to form mitre joints, each of the abutting faces of the joint provided with one or more kerfs or grooves of substantially like size and extent cut in the direction of the frame and, upon abutment of the members with the paired kerfs then coming into alignment, adapted to accept inserted rabbet tongues WHEREIN the kerfs are cut grooves of a lesser extent than the length of the abutting faces, the tip end or leading edge of the correspondingly shorter rabbet tongue provided with protrusions adapted to coact with or to spike into the now blind end of said grooves to secure the jointing.

2. Mitre joints of a frame according to claim 1 with rabbet tongues inserted in the direction of the plane of the frame into the correspondingly grooved frame members WHEREIN the grooves cut into the abutment faces extend angularly towards and open-out at the frame members' side edges.

3. Mitre joints of a frame according to claim 2 WHEREIN the grooves are cut at right angles to the direction of the plane of the mitre, opening out at the frame members' side edge.

4. Joints between pairs of grooved frame members according to any of the preceding claims WHEREIN the rabbet tongues that are inserted into the grooves are of wood, plastic, or of metal.

5. Mitre joints of a frame according to claim 4 WHEREIN the rabbet tongues are made of wood with at least two protrusions jutting from the tip end, else, with spikes in the leading edge of the rabbet tongue.

6. Mitre joints of a frame according to claim 5 WHEREIN the two spikes or pairs of spikes are diverging relative to the leading edge of the rabbet tongue and to one another.

7. Mitre joints of a frame according to claims 4 and 6 WHEREIN the flat surface of the rabbet tongue comprises divergent ridges.

8. Mitre joints of a frame according to claims 4 and 7 WHEREIN ridges on the top and/or bottom surface of the rabbet tongue extend as spikes from the leading edge of the rabbet tongue.

9. Mitre joints of a frame according to claims 4 and 7 WHEREIN the rabbet tongues are flat, metallic stampings with a serrated tip end and embossed with straight, divergent lines or opened-out divergent ridges.

10. Method of manufacture of a mitre joint of a frame according to Claims 2-9 WHEREIN a pair of frame members are placed at an angularly abutting position, their abutting faces either pre-cut or post-cut across the mitre by one or more sawn kerfs in the plane of the frame, inserting at the mitre apex one or more flat or ridged rabbet tongues of the same, substantially triangular shape as that of the cut kerf and, after internally meeting the opposing frame members and for finally homing the rabbet tongues, the spikes at the leading edge of the rabbet tongue are then driven home into the frame material to effect a concealed and secure joint.

10. Method of manufacture of a mitre joint of a frame according to claims 2-9 WHEREIN a pair of frame members are placed at an angularly abutting position, their abutting faces either pre-cut or post-cut across the mitre by one or more sawn kerfs in the plane of the frame, inserting one or more flat or ridged rabbet tongues of the same, substantially tri angular shape as that of the cut kerf and, after internally meeting the opposing frame members and for finally homing the rabbet tongues, the spikes at the leading edge of the rabbet tqngue are then driven home into the frame material to effect a concealed and secure joint.

11. Method of manufacture of a mitre joint of a frame according to claim 10 WHEREIN prior to inserting the rabbet tongues, adhesive is applied to the abutting faces of the frame members and/or the kerfs and/or the rabbet tongues.

12. Method of manufacture of a mitre joint of a frame according to claims 10 and 11 WHEREIN after inserting rabbet tongues into the mitred frame and driving them home inside the kerf to secure the intended mitre shape, a- curable resinous material, a settable or extrudable plastic, is pressure injected into the joint to seal any remaining voids between the faces of the abutting frame members and/or between the kerf and the rabbet tongue, this resinous or plastic material upon setting to bond the coacting frame members CLAIMS Amendments to the claims have been filed, and have the following effect: Claims 1, 2 & 10 above have been textually amended.

New or textually amended claims have been filed as follows: .

1.- Joint between a pair of members made of wood or of another nailable or incisable material, in particular corner constructions of frames with members abutting one another to form mitre joints, each of the abutting faces of the joint provided with one or more kerfs or grooves of substantially like size and extent cut in the direction of the frame and, upon abutment of the members with the paired kerfs then coming into alignment, adapted to accept rabbet tongues inserted at the mitre apex, WHEREIN the kerfs are cut grooves of a lesser extent than the length of the abutting faces, the tip end or leading edge of the correspondingly shorter rabbet tongue provided with protrusions adapted to coact with or to spike into the now blind end of said grooves to secure the jointing.

2. Mitre joints of a frame according to Claim 1 with rabbet tongues inserted from the apex in the direction of the plane of the frame into the correspondingly grooved frame members WHEREIN the grooves cut into the abutment faces extend angularly towards and open-out at the frame members' side edges.