Patent Description:
Ready to assemble furniture has been known in the furniture industry for many years. This type of furniture construction provides a number of advantages to the manufacturer, to the retailer, and to the customer. For example, as to the manufacturer, there are significant cost savings in manufacturing unassembled furniture over conventional fully assembled furniture. Ready to assemble furniture can be supplied flat packed, thus requiring less storage space for both the manufacturer and the retailer. The customer ultimately benefits the lower cost of ready to assemble furniture as opposed to pre-assembled furniture and the ease of transport of flat packed ready to assemble furniture.

Unlike conventional fully or pre-assembled furniture, ready to assemble furniture, as the name implies, requires assembly by the customer. This furniture often requires the use of tools by the customer to enable the manipulation of specialized fittings to assemble and secure the various components of the furniture together. The customers may not have the necessary tools or skill level to assemble the furniture properly. The failure to do so may result in the furniture being unstable, and potentially collapsing during use.

A commonly used type of coupling element in ready to assemble furniture is a dowel pin adapted to be inserted into a hole bored into at least one of two components to be coupled. Traditionally such dowel pins comprise wooden pins that are inserted into said axially aligned holes in abutting faces of adjacent components along with adhesive for fixing the dowels into said holes. Alternatively, such down pins may comprise cylindrical elongate plastic element having barbs integrally formed on the sides thereof, the barbs being shaped to hinder or prevent the removal of dowel pin from the hole into which it is inserted. Such barbs are typically in the form of collars which are circumferentially disposed around the elongate member. However, known plastic barbed dowel pins tend to be poor at resisting axial forces acting to remove such dowel pins from said holes. <CIT> discloses a known fastening dowel.

According to the present invention there is provided a coupling element as claimed in claim <NUM>.

In one embodiment said at least one coupling member may comprise a dowel, a second plurality of barbs being disposed successively along the coupling member from the second end and depending inwardly from said second end so as to hinder or prevent the removal of the coupling element from a bore in a surface of a second article into which the coupling member has been inserted from the second end, wherein a first set of said second plurality of barbs extend in cantilever manner from said flat face of said first side of the coupling member.

A second set of said second plurality of barbs may extend from said curved face of said second side of the coupling member.

The second end of the at least one coupling member may be attachable to or integrally formed with a second article to be coupled to said first article. In one embodiment said second end of the coupling member may be integrally formed with a male connector for attaching the coupling element to a second article. The at least one coupling member may extend from a base portion of a male connector for attaching the coupling element to a second article. The male connector may comprise an elongate base member from which said at least one coupling member extends, the second end of said at least one coupling member being coupled to or integrally formed with said base member of the male connector, said male connector including a coupling portion extending from said base member to be received within a slot in said second article or within a female connector mounted therein. The coupling portion may comprise an elongate ridge having flared sides adapted to retain said coupling portion of the male connector within said slot.

Other types of male connector are envisaged, such as a plug adapted to engage a bore formed in a side face of a first article bore intersecting an edge face from which the coupling member extends when the plug is inserted in said bore such that the coupling member extends from said edge face to engage an aperture in an adjoining face of a second article.

A plurality of said coupling members may extend from said elongate base of the male connector substantially perpendicular to a bottom face of said elongate base and parallel to one another.

The first and second sets of barbs and the second plurality of barbs of at least the first plurality of barbs each consist of at least three, preferably three to ten, most preferably three to six barbs.

Each barb of said first set of barbs may adjoin said flat face of the or each coupling member via a reduced thickness region serving as a live hinge.

Coupling elements for joining articles in accordance with various embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which :-.

A coupling element in accordance with a first embodiment of the present invention is illustrated in <FIG>. In this first embodiment, the coupling element is in the form of a dowel for joining abutting faces of two articles by insertion into axially aligned holes or blind bores. The coupling element comprises an coupling member <NUM> having a first end <NUM> and a second end <NUM>, the first end <NUM> of the coupling member being insertable into a first hole formed in a surface of the first article and the second end <NUM> being insertable into a second hole formed in a surface of the second article. A first plurality of barbs is disposed successively along the coupling member from the first end and depending away from said first end so as to hinder or prevent the removal of the coupling element from the respective bore into which the first end of the coupling member has been inserted, and a second plurality of barbs are disposed successively along the coupling member from the second end and depending inwardly from said second end so as to hinder or prevent the removal of the coupling element from the hole into which the second end of the coupling member has been inserted.

The coupling member <NUM> has a flat face <NUM> on a first side thereof, a first set <NUM> of each of said first and second plurality of barbs extending in cantilever manner from said flat face <NUM>, the coupling member <NUM> having a curved face <NUM> on a second side thereof, opposite said first side, a second set <NUM> of said first and second plurality of barbs, having an arcuate shape, extending from said curved face <NUM>.

The outermost ends of the first and second sets of barbs <NUM>,<NUM> of said first and second plurality of barbs are shaped to define a substantially cylindrical outer surface of the coupling element of slightly larger diameter than that of the holes or bores into which it is intended to insert the coupling element.

In use, as illustrated in <FIG>, the first and second ends <NUM>,<NUM> of the coupling element are inserted into respective holes or blind bores in abutting faces of first and second articles to be coupled together, each hole or blind bore having a diameter slightly less than that of the outer diameter of the coupling element, such that the first and second plurality of barbs are compressed inwardly as the respective end of the coupling element is inserted therein. Each of the first and second sets <NUM>,<NUM> of said first and second plurality of barbs face away from said respective first and second ends <NUM>,<NUM> of the coupling member <NUM> defining the coupling element such that the barbs <NUM>,<NUM> resist removal of the coupling element from the holes or blind bores into which it is inserted.

Each first set of said first and second plurality of barbs <NUM> extend in cantilever manner from the flat face <NUM> of the coupling member to provide enhanced resistance to removal by virtue of said first sets of barbs <NUM> being longer than the arcuate second sets of barbs <NUM> extending from the second curved face <NUM> of the second side of the coupling member <NUM>, said first sets of barbs <NUM> providing a relatively strong lever action against the sides of the hole or bore compared to known arcuate barbs, such that said first sets of barbs <NUM> act to urge the second sets <NUM> of barbs against the side of the respective hole or bore into which the coupling element is inserted, thereby providing enhanced resistance to removal of the coupling element from the holes or bores into which it is inserted. As illustrated in <FIG>, the first set of barbs <NUM> have forced the opposite less-flexible second set of barbs <NUM> further into the sides of the respective bore or hole, whereby making the coupling member easy to push into said respective hole or bore but difficult to remove. Because of the flexibility in the first set of barbs <NUM>, the resistance in insertion is reduced but when pulling out - the barbs <NUM>,<NUM> 'bite' in deeper into the sides of the bore, thereby increasing the residual strength in the coupling.

Each barb of said first set of barbs <NUM> may adjoin said flat face <NUM> of the coupling member <NUM> via a reduced thickness region serving as a live hinge. When pushed in to a hole, a recess or a channel each first set of barbs <NUM> act in such a way as to apply pressure onto the opposite side of the hole, recess or channel, allowing that side to be wedged or imbedded into the wall of the hole, recess or channel.

The cantilevered first sets of barbs <NUM> force the opposite second sets of barbs <NUM> to 'pinch' on the adjacent side of the bore/hole increasing the residual holding strength and making it harder to remove.

Additionally, when force acting to remove the coupling element from the hole, recess or channel into which it has been inserted, this force is converted by the cantilevered barbs <NUM> into a more sidewards pushing force, which in turn applies more pressure onto the barbs <NUM> on the opposite side of the elongate coupling element, allowing that side to be further wedged or imbedded into the side wall of the hole or channel.

It should also be noted that the cantilevered barbs <NUM> are shaped in such a way that only a small amount of a downward force is required to push the coupling element into a hole or channel.

By providing said first and second set of barbs <NUM>,<NUM> of each of said first and second plurality of barbs on opposite first and second sides of the coupling member <NUM>, the barbs <NUM>,<NUM> acts against the inner sides of a hole or blind bore into which the respective end of the coupling member <NUM> is inserted on diametrically opposed sides of the hole or bore. Advantageously, this enables the coupling element to be inserted into a hole or bore in an edge of a panel without the risk of splitting the panel by aligning the first and second sets of barbs <NUM>,<NUM> along the length of the panel, thereby minimising outwards forces perpendicular to the side faces of the panel and any bulging of said side faces of the panel.

In an alternative embodiment, illustrated in <FIG>, the coupling element comprises an coupling member <NUM> having a first end <NUM> and a second end <NUM>, the first end <NUM> of the coupling member being insertable into a first hole or blind bore formed in a surface of a first article and the second end <NUM> being integrally coupled to a further connector portion <NUM> for attaching the coupling element to a second article. As before, the coupling member <NUM> has a plurality of barbs therealong for retaining the coupling member in a hole or blind bore into which it is inserted, the coupling member having a flat face <NUM> on a first side thereof, a first set of said plurality of barbs <NUM> extending in cantilever manner from said flat face <NUM>, and a curved face <NUM> on a second side thereof, opposite said first side, a second set of said plurality of barbs <NUM>, having an arcuate shape, extending in from said curved face <NUM>.

As shown in <FIG>, the further connector portion <NUM> may comprise male connector comprising an elongate base member <NUM> from a lower face of which said coupling member <NUM> extends, the second end <NUM> of said coupling member <NUM> being coupled to or integrally formed with said lower face of the base member <NUM> of the male connector <NUM>, said male connector including a coupling portion <NUM> extending from said base member <NUM> to be received within a slot in said second article or within a female connector mounted therein. The male connector <NUM> may be of the type disclosed in <CIT>, incorporated herein by reference, wherein the coupling portion comprises a central rib extending outwardly from the base member, a distal end of the central rib supporting a pair of outwardly flared symmetrically arranged resilient wings on either side thereof, said wings extending towards the base member, the resilient wings have a substantially arrow head shaped cross section extending on either side of the central rib to be retained in a receiving slot formed in face of a second article of in a respective female coupling mounted in a face of said second article. It is envisaged that the further connector portion <NUM> may be adapted for numerous functions, with numerous different constructions to enable the coupling element to be used with different products and articles.

The first and second sides of the coupling member <NUM> may be aligned with respect to the base member <NUM> of the male connector <NUM> such that the flat face <NUM> of the first side of the coupling member <NUM> extends substantially transverse to an elongate axis of the elongate base member <NUM> of the male connector <NUM>, said first set of barbs <NUM> extending towards one end of said elongate base member <NUM>, enabling the coupling element to be inserted into a hole in an edge of a panel without the risk of splitting the panel by aligning the first and second sets of barbs <NUM>,<NUM> with the length of the panel.

In a further embodiment, illustrated in <FIG>, the coupling element comprises a male connector <NUM> comprising an elongate base member <NUM> a coupling portion <NUM> extending from said base member <NUM> to be received within a slot in said second article or within a female connector mounted therein, said base member being longer than that of the embodiment shown in <FIG>. Due to the increased length of the male connector <NUM>, a respective coupling member 2A,2B extends from either end of the base member <NUM> of the male connector <NUM>, said coupling members 2A,2B extending parallel to one another and perpendicular to a lower face of said base member <NUM>.

Each coupling member 2A,2B includes a plurality of barbs disposed successively therealong, said plurality of barbs depending away from a distal end of the respective coupling member 2A,2B so as to hinder or prevent the removal of the each coupling member 2A,2B from a respective hole or bore into which it is inserted.

As before, each coupling member 2A,2B has a flat face <NUM> on a first side thereof, a first set of said plurality of barbs <NUM> thereof extending in cantilever manner from said flat face <NUM>, each coupling member 2A,2B having a curved face <NUM> on a second side thereof, opposite said first side, a second set of said plurality of barbs <NUM>, having an arcuate shape, extending in from said curved face <NUM>.

In the embodiment shown, the male connector member <NUM> includes a central rib extending outwardly from the base member, a distal end of the central rib supporting a pair of outwardly flared symmetrically arranged resilient wings on either side thereof, said wings extending towards the base member, the resilient wings have a substantially arrow head shaped cross section extending on either side of the central rib. Each wing may be curved in an outwards direction away from the respective central rib from the base region to the free ends of the wings. The resilient wings of the male connector are resiliently displaceable towards to the central rib to enable the wings to pass through a narrowed neck region of a receiving slot in an article or a female connector member mounted in a slot formed in a face of an article, the ends of the resilient wings engaging shoulders of the receiving slot of female connector once the male connector has been inserted therein to retain the male connector therein. However, other types of male connector or alternative connector portions are envisaged.

Again, the first and second sides of each coupling member 2A,2B may be aligned with respect to the base member <NUM> of the male connector <NUM> such that the flat face <NUM> of each coupling member extends substantially transverse to an elongate axis of the base member <NUM> of the male connector <NUM> so that the barbs <NUM>,<NUM> are aligned along the length of the male connector <NUM>. This enables the coupling element to be inserted into a hole in an edge of a panel without the risk of splitting the panel by aligning the first and second sets of barbs with the length of the panel. In the embodiment shown in <FIG> the flat faces <NUM> of the coupling member 2A,2B face one another so that the first set of barbs <NUM> of each coupling member are arranged to extend away from a respective adjacent outer end of said elongate base member <NUM>.

<FIG> illustrate a coupling element <NUM> not falling within the scope of the present invention and having first and second flat faces 108A, 108B on both first and second sides thereof, a respective first and second plurality of barbs 110A,110B extending in cantilever manner from each of said first and second flat faces 108A,108B.

As illustrated in <FIG>, in an alternative embodiment the curved face <NUM> on the second side of the coupling element <NUM> may have a plurality of ridges <NUM> formed thereon instead of barbs, said ridges <NUM> being pushed into gripping engagement with a side wall of a hole into which the coupling element <NUM> is inserted by the pressure applied onto the opposite side of the hole by the cantilevered barbs <NUM> provided on the flat face <NUM> of the first side of the coupling element <NUM>.

In the embodiment illustrated in <FIG>, in a further embodiment the ridges <NUM> on the curved side <NUM> of the coupling element <NUM> may have a rounded outer profile.

As illustrated in <FIG>, a coupling element in accordance with a further embodiment of the invention may be adapted to be inserted into opposing slots or channels in components to be coupled, the coupling element <NUM> in the form of an elongated dowel for joining abutting faces of two articles by insertion into axially aligned slots or channels, the coupling element <NUM> having a first end <NUM> and a second end <NUM>, the first end <NUM> of the coupling element being insertable into a first slot or channel formed in a surface of the first article and the second end <NUM> being insertable into a second slot or channel formed in a surface of the second article.

A first set of barbs <NUM> are provided on one a first side <NUM> of the coupling element <NUM> while a second set of barbs <NUM> are provided on a second side <NUM> of the coupling element <NUM>. The first set of barbs <NUM> extend in cantilever manner from the flat first side <NUM> of the coupling element <NUM>. A second set of barbs <NUM> extend from the second side <NUM> of the coupling element <NUM>, the second set of barbs <NUM> being shorter than the first set of barbs <NUM> and extending around curved ends of the coupling element at either end of said first side <NUM>.

As with previous embodiments, the cantilevered first sets of barbs <NUM> force the opposite second sets of barbs <NUM> against the adjacent side of the slot or channel into which the coupling element <NUM> is inserted, increasing the residual holding strength and making the coupling element harder to remove.

Additionally, when force acting to remove the coupling element <NUM> from the slot or channel into which it has been inserted, this force is converted by the cantilevered barbs <NUM> into a more sidewards pushing force, which in turn applies more pressure onto the barbs <NUM> on the opposite side of the elongate coupling element, allowing that side to be further wedged or imbedded into the side wall of the slot of channel into which it is inserted.

In a further embodiment, illustrated in <FIG>, the coupling element comprises a coupling member <NUM> having a first end <NUM> and a second end <NUM>, the first end <NUM> of the coupling member being insertable into a first hole or blind bore formed in a surface of a first article and the second end <NUM> being integrally coupled to a further connector portion <NUM> for attaching the coupling element to a second article. As before, the coupling member <NUM> has a plurality of barbs therealong for retaining the coupling member in a hole or blind bore into which it is inserted, the coupling member having a flat face <NUM> on a first side thereof, a first set of said plurality of barbs <NUM> extending in cantilever manner from said flat face <NUM>, and a curved face <NUM> on a second side thereof, opposite said first side, a second set of said plurality of barbs <NUM>, having an arcuate shape, extending in from said curved face <NUM>. It is envisaged that the second side may also comprise a flat face having cantilevered barbs, as described in relation to <FIG>, or may just incorporate ribs or ridges, as described in relation to <FIG>.

In this embodiment, the further connector portion may comprise a plug <NUM> adapted to be fitted into a bore formed in a side face of a first article bore intersecting an edge face from which the coupling member <NUM> extends when the plug <NUM> is inserted in said bore such that the coupling member <NUM> extends from said edge face to engage an aperture in an adjoining face of a second article. In the embodiment shown in <FIG>, in the same manner as provided on the coupling member <NUM>, the plug <NUM> includes a flat face <NUM> on a first side thereof from which extends a first plurality of barbs <NUM> in cantilever manner for engaging an inner wall of the bore into which the plug <NUM> is inserted to retain the plug <NUM> within the bore. A second plurality of barbs <NUM>, having an arcuate shape, extend from a curved face <NUM> on a second side of the plug <NUM>.

Claim 1:
A coupling element comprising at least one coupling member (<NUM>) having a first end and a second end (<NUM>,<NUM>),
wherein said coupling member has a flat face (<NUM>) on a first side thereof,
the at least one coupling member (<NUM>) includes a first plurality of barbs disposed successively therealong from the first end,
a first set (<NUM>) of said first plurality of barbs extending from said flat face (<NUM>) and extending in cantilever manner from said flat face (<NUM>) and depending away from said first end (<NUM>) so as to hinder or prevent the removal of the coupling element from a bore in a surface of a first article into which the coupling member (<NUM>) has been inserted from the first end,
wherein said at least one coupling member has a curved face (<NUM>) on a second side thereof, opposite said first side, a second set (<NUM>) of said first plurality of barbs extending from said curved face (<NUM>) or a plurality or ridges (<NUM>) or projections being disposed successively along said second side of the at least one coupling member.