GB1569925A

GB1569925A - Dowelled joint for furniture

Info

Publication number: GB1569925A
Application number: GB31121/77A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-07-31
Filing date: 1977-07-25
Publication date: 1980-06-25
Also published as: DK342377A

Description

(54) A DOWELLED JOINT FOR FURNITURE (71) 1, KLAUS BRUMMERNHENRICH, a German Citizen, of Meerbrede 2, D-4902 Bad Saizufien 7, Federal Republic of Germany, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a dowelled joint for furniture parts and the like and to a piece of furniture including parts joined together by such a joint.

With known joints of this kind the dowels are glued to the parts to be joined.

Additionally, the parts are glued at the mitre or the abutting surfaces. Corner joints are also known in which the parts sit together mechanically, whereby snap locks between the connections and the frame parts are preferred. These joints however, are only suitable for furniture frames made of plastic having the elasticity necessary to provide a snap fit. For furniture frames made of solid wood or chipboard by which the connecting elements, such as corner connections, take the form of dowels located on holes, such form-fit connections are not yet available.

Because glueing is necessary a dowelled joint is expensive, apart from which, the parts joined together cannot subsequently be disconnected. Apart from this, the chipboard material tends to break at the joint or to crumble after a time whereby the dowel connection dislocates in such a manner that subsequent glueing is no longer possible.

An object of the present invention, there fore, is to produce an improved dowelled joint in which the dowel is releasably secured to at least one of the two parts joined together.

According to this invention a dowelled joint for furniture parts and the like, has in at least one of the parts joined together, a bore which is transverse to and communicates with a dowel bore and which contains a plug having at its inner end a slot receiving a portion of the dowel intermediate its ends and thinner than the remainder of the dowel, the length of the slot in the plug corresponding to the length of the thinner portion of the dowel, and the flanks of the thinner portion being chamfered, whereby the plug and dowel fit together by engagement of the thinner portion in the slot, so as to releasably secure the dowel to the said part.

One advantage of the new furniture frame is that the dowel connection of the two parts can be achieved with fewer manual operations than were necessary hitherto, by inserting the dowel, which is already secured to one of the parts, into the usual dowel hole and then fitting the locking plug into the bore which intersects the dowel hole. The dowelled joint can be released at any time by removing the plug. On the other hand, inadvertent release of the locking plug can be prevented by making a press fit between the separable parts.

In one embodiment of the invention, the said thinner portion is slightly larger than the width of the slot in the plug. The plug is thus forced to spread on being inserted and becomes firmly wadged in the bore.

In another embodiment, the plug and/or the dowel are made of an elastic material so that these parts themselves can yield when the plug slot is pushed over slightly larger reduced diameter portion of t he dowel.

To avoid having to insert the dowel into the dowel hole in a given position, the thinner portion of the dowel is preferably cylindrical.

With sufficient pressure between the plug and the said portion of the dowel, the friction between the two parts is enough to secure the dowel axially within the dowel hole, whereby the form-fit is achieved solely by the seating of the plug in the bore. However, since the length of the plug and hence the diameter of the plug, corresponds to the axial length of the thinner portion of the dowel, a frictional lock between the plug and the dowel is not important because a form-fit exists between the plug and the flanks of the said thinner portion in the axial direction of the dowel.

Chamfering the flanks of the thinner portion and of the slot edges on the plug achieves a wedge effect between the plug and the narrow portion of the dowel. Finally, the slot edges can spread wedge-like in the direction of the plug axis in order order to plug on the dowel. For the same purpose, the plug may be tapered from the opening inwards.

To ensure sufficiently firm seating of the plug at the intersection of the dowel hole and the bore, it is advantageous that the diameter of the plug and the corresponding bore in the said one part be made larger than the diameter of the dowel and its corresponding hole.

In order to make the plugs as inconspicious as - possible, the plugs may be set with their top faces flush with the surface of the corresponding part, removal of the plugs being possible with the aid of suitable tools.

The invention also includes a piece of furniture including parts which are joined together by a joint accbrding to this in Yentiori.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings of which: - Figure 1 is a perspective view of a drawer including a dowelled joint according to the invention, Figure 2 is a section through the dowelled joint between the side part and the front piece at position II in Figure 1, Figure 3 is a section through the dowelled joint along the line III-III in Fig. 2, Figure 4 is a section through the dowelled joint at the corner between the side part and the back at IV in Fig. 1, Figure 5 is a view of a modified locking plug for a dowelled joint according to Figs 2 to 4.

A drawer can be seen in Figure 1, consisting of a front piece 1, two sides parts 2, a back 3 and a base 4. In a known manner, the front piece 1, the side parts 2 and the back form a frame which is selected as an example of a furniture frame. The individual parts of this furniture frame are secured together at the corner or butt positions by dowelled joints whereby straight dowels as well as angled dowels can be used.

Figure 2 shows a section through the joint between the front piece 1 and the side part 2 of the drawer in Figure 1, whereby the front piece 1 abuts the end of the side part 2 and correspondingly a straight dowel 5 is used. The dowel 5 is set with one end 6 in a blind hole 8 in the front piece 1, and is secured therein by means of barbed ribs 7. The other end 9 of the dowel 5 engages the dowel hole 10 in the side part 2, which hole as a rule is cylindrical, as too is the dowel 5.

The dowel 5 has on the end 9 wthin the side part 2 a portion 11 which is thinner than the dowel 5 and, in particular takes the form of a cylindrical core 12 of lesser diameter than the dowel 5, having sloping flanks 13 to the outer surface of the dowel 5.

In the region of the thinner portion 11 of the dowel 5 is a bore 19, open to at least one of the two face sides of the side part 2, and at right-angles to the longitudinal axis of the dowel 5. Thus the bore 19 intersects the dowel hole 10 which is preferably somewhat smaller in diameter than the bore 19.

Within the bore 19, is fitted a plug 14 having a slot 15 across its inner end with which it engages the dowel 5 at the thinner portion 11. The slot 15 is so formed on the plug 14, that its length corresponds to the length of the thinner portion 11 so that the edges 16 of the slot 15 in a properly inserted plug 14 engage the flanks 13 of the thinner portion 11. In this way, the dowel 5 is secured against axial movement. Preferably the slot edges 16 of the plug 14 are sloped throughout, so that the open slot entrance on the base of the plug 14 is bevelled to facilitate assembly of the plug 14 over the thinner portion 11 of the dowel 5. The sloping sides of the slot edges 16 and the sloping flanks 13 of the thinner portion -11 on the dowel 5 create a wedge effect which with a press fit ensures a secure joint between all removable parts.

The dowel 5 or the plug 14 or both parts may be of elastic material, whereby then, the width of the slot 15 can even be smaller than the diameter of the core 12 at the thinner portion 11 of the dowel 5, so that the plug 14 can only engage the dowel subject to reslient deformation. By suit ably widening the base of the slot in the plug 14, it is even possible to produce a snap fit between the plug 14 and the dowel 5. On the other hand, spreading of the plug 14 may assist in wedging it within the bore 19.

The top surface 17 of the plug 14 is flush with the corresponding surface 18 of the side part 2, so that the bore 19 is thus outwardly completely closed. Even in this em bodiment, the plug 14 is easily removed from the bore 19 using a suitable tool.

Figure 3 shows the plug 14 of the dowelled joint once again in a side view. The sloped slot edges 16 which extend over the slot opening are especially evident here.

Whereas Figure 2 shows an example of a straight dowel, only one end of which has a dowelled joint according to the invention, Figure 4 depicts an angled dowel 5, the two arms of which are secured respectively to the side part 2 of the drawer and to the back 3 in the manner already described. With the mitre-joined parts 2 and 3 where the dowel holes 10 extend from the joint, it is possible to provide a bore 19 which is necessary for receiving the plug 14 on both parts.

Figure 5 shows yet another embodiment of the plug 14 on which the slot 15 is tapered inwardly. By suitable choice of diameter for the core 12 at the narrow portion 11 of the wedge angle for the slot 15, a self-locking engagement of the plug 14 to the thinner portion 11 of the dowel 5 can be achieved. Finally, the plug 14 can be conically formed about the area of the slot 15 in order that a clamping effect occurs by means of the sloped slot edges 16 and the equally sloped flanks 13 of the thinner portion 11.

WHAT WE CLAIM IS: 1. A dowelled joint for furniture parts and the like having, in at least one of the parts joined together, a bore which is transverse to and communicates with a dowel bore and which contains a plug having at its inner end a slot receiving a portion of the dowel intermediate its ends and thinner than the remainder of the dowel, the length of the slot in the plug corresponding to the length of the thinner portion of the dowel, and the flanks of the thinner portion being chamfiered, whereby the plug and dowel fit together by engagement of the thinner portion in the slot, so as to releasably secure the dowel to the said part.

2. A joint according to claim 1 wherein the said portion of the dowel is slightly larger than the width of the slot in the plug.

3. A joint according to claim 2 wherein the dowel and/or the plug are made of an elastic material.

4. A joint according to claim 2 or 3 wherein the thinner portion of the dowel is cylindrical.

5. A joint according to any one of the claims 1 to 4, wherein the diameter of the plug and the corresponding bore in the said part is greater than the diameter of the dowel and its corresponding dowel hole.

6. A joint according to any one of the claims 1 to 5 wherein the top side of the plug is flush with the surface of the part.

7. A joint according to any one of the claims 1 to 6 wherein the slot diverges toward the inner end of the plug.

8. A dowelled joint for furniture parts and the like, constructed and arranged substantially as herein before described with reference to and as illustrated in the accompanying drawings.

9. A piece of furniture including parts which are joiped together by a dowelled joint according to anyone of claims 1 to 8.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. bodiment, the plug 14 is easily removed from the bore 19 using a suitable tool. Figure 3 shows the plug 14 of the dowelled joint once again in a side view. The sloped slot edges 16 which extend over the slot opening are especially evident here. Whereas Figure 2 shows an example of a straight dowel, only one end of which has a dowelled joint according to the invention, Figure 4 depicts an angled dowel 5, the two arms of which are secured respectively to the side part 2 of the drawer and to the back 3 in the manner already described. With the mitre-joined parts 2 and 3 where the dowel holes 10 extend from the joint, it is possible to provide a bore 19 which is necessary for receiving the plug 14 on both parts. Figure 5 shows yet another embodiment of the plug 14 on which the slot 15 is tapered inwardly. By suitable choice of diameter for the core 12 at the narrow portion 11 of the wedge angle for the slot 15, a self-locking engagement of the plug 14 to the thinner portion 11 of the dowel 5 can be achieved. Finally, the plug 14 can be conically formed about the area of the slot 15 in order that a clamping effect occurs by means of the sloped slot edges 16 and the equally sloped flanks 13 of the thinner portion 11. WHAT WE CLAIM IS:

1. A dowelled joint for furniture parts and the like having, in at least one of the parts joined together, a bore which is transverse to and communicates with a dowel bore and which contains a plug having at its inner end a slot receiving a portion of the dowel intermediate its ends and thinner than the remainder of the dowel, the length of the slot in the plug corresponding to the length of the thinner portion of the dowel, and the flanks of the thinner portion being chamfiered, whereby the plug and dowel fit together by engagement of the thinner portion in the slot, so as to releasably secure the dowel to the said part.