Patent Description:
More specifically, the present invention relates to a device suitable for assembling furniture and/or furnishing accessories such as shelves, bookcases, drawer units, bed frames, seats and the like.

As is known, furniture and furnishing accessories are increasingly made by stably and unmovably joining together single parts that will go to define the overall assembly represented, for example, by a bookcase or a shelf, a chair or any other furnishing accessory not made in a single piece but defined by an assembly of single parts.

Such a "kit" structure entails considerable advantages linked, for example, to an ease of transport of even bulky structures, to the possibility of assembling the furniture item directly on site or, likewise, to the possibility of transport and assembly also by non-expert users.

The retaining elements used to join together the different components or individual parts of the furniture are defined, for example, by tie-rods or bushings, cams and similar means.

Referring by way of example to a bookcase or shelf-type item of furniture, it typically comprises two vertical uprights, tendentially parallel one in relation to the other, between which are interposed, along a plane perpendicular to the plane of longitudinal development of the uprights, one or more shelves having the function of defining a plane of resting and support for books, magazines, vases and/or other multiple and different objects.

The assembly of the frame structure and the shelves with respect to said frame can be carried out using retaining means represented by bushings or cams inserted in the thickness of the shelves (or of the uprights) and co-operating in clamping with corresponding pins or screws inserted in the uprights (or in the shelves) and which, actuated by means of a suitable tool (screwdriver or Allen key or the like), determine the rotation of the bushing or cam so as to realise the constraint of said pin or screw with respect to said bushing or cam.

However, these means of clamping or constraint involve some major disadvantages linked to the need to make slots for the housing of the components in co-operation (bushing and screw or pin) in the thickness of the parts in reciprocal coupling (both in the shelves and uprights).

Furthermore, said clamping means involve longer assembly times, since the operator must insert the bushing or cam and the screw or pin in the respective seats and then act on the screw or pin to create the clamping.

In order to remedy these disadvantages, other removable joining methods have been developed that provide for the use of expansion joints suitable for insertion in the thickness of the uprights or of the shelves, with said joints that comprise an expansion bushing typically made of plastic material and a screw inserted coaxially to said bushing and, also, a cam bushing inserted in a slot formed in the thickness of one of the parts to be joined and suitable for coupling with the screw or pin of the expansion joint. The reciprocal clamping between the two components of the furniture item is carried out by means of a tool which acts on the cam bushing and which, rotating, forces a backward movement of the pin with respect to the bushing in which the pin is inserted with a consequent radial expansion of the bushing itself.

However, these traditional expansion joints also entail some major disadvantages linked to the fact that they comprise elements to be inserted in both parts to be assembled with the consequent need to create suitable seats and grooves in said parts of the furniture.

A further disadvantage is linked to the longer assembly times, in that the user must insert the expansion joint elements in the seats of the parts to be connected and subsequently has to act on the cam bushing to impose the movement of the pin and the consequent expansion of the bushing in its seat.

A further disadvantage is represented by the fact that a possible loosening of the cam bushing involves a consequent movement of the pin and a return into the non-expanded position of the bushing of the pin and this may cause an inevitable loosening of the clamping constraint between the parts of the furniture item.

Joining devices have also been proposed that allow a simultaneous fastening to the two parts of the furniture item to be connected.

Such a device is, for example, described in <CIT> and comprises a casing or container body designed to be inserted, with the respective ends, in seats formed in the components of the furniture item to be joined. The casing is made in two parts that are firmly restrained one to the other and encloses in its interior a cam mechanism that acts on actuation means, such as a slide or slider that causes the expansion of components placed at the end of the casing.

This device, although it solves the problems of the joining devices described above, has the disadvantage of being made up of several separate components housed in the casing, which makes the device expensive and complex to assemble, as well as affecting its long-term reliability.

<CIT> discloses an elongated fastener for securing a pair of panels together. Each end of the fastener comprises an expansible end portion thereon which is arranged to be received within a bore in a respective panel. A wedge member is mounted within each expansible end portion for longitudinal sliding movement between a disengaged position and an engaged position wherein the expansible end portions are expanded relative to the disengaged position. An actuator is located centrally between the expansible end portions for pivotal movement about an actuator axis. Other joining devices and methods are known from <CIT> and <CIT>.

The object of the present invention is to overcome the abovementioned disadvantages. In particular, one object of the invention is to provide a joining device for parts of furniture and furnishing accessories that is made up of the smallest possible number of components and is therefore economical and fast and easy to assemble.

Another object of the present invention is to provide such a joining device that is highly reliable, guaranteeing excellent clamping between the parts to be assembled without any risk of loosening.

These and other objects are achieved by the device according to the invention which has the features of the appended claim <NUM>.

Advantageous embodiments of the invention are disclosed by the dependent claims.

The constructional and functional features of the joining device for parts of furniture or furnishing accessories of the present invention will be made clearer by the following detailed description in which reference is made to the accompanying drawings which illustrate an embodiment thereof given solely by way of a nonlimiting example and in which:.

Referring to the aforementioned drawings, the joining device for parts of furniture or furnishing accessories of the present invention, denoted overall by reference numeral <NUM>, is substantially made up of a casing <NUM>, made in two parts <NUM>, <NUM>, between which a cam mechanism <NUM> is interposed, whose actuation allows a predetermined axial sliding between said parts <NUM>, <NUM>, as will be explained here below.

The casing <NUM> is substantially cylindrical in shape, and the two parts <NUM>, <NUM> here below for the sake of convenience will also be referred to as half-shells, respectively upper half-shell <NUM> and lower half-shell <NUM> with reference to the accompanying drawings, although their configuration is substantially different, as will be seen here below. The half-shells <NUM> and <NUM> are made in materials of different hardness for the purposes that are to be stated. In particular, the lower half-shell <NUM> is in a plastic that has a certain flexibility, while the upper half-shell <NUM> is in metal, in particular zamak, or also in a hard plastic. Here below the two half-shells <NUM> and <NUM> will be indicated in metal and plastic, respectively.

The two half-shells are joined one to the other by means of a snap-fit type connection, i.e. with slotting means, without using fastening means, so as to allow the aforementioned axial sliding between the two.

The upper metal half-shell <NUM> has a somewhat thinned shape, with a widened median section <NUM>, at which a circular through hole <NUM> is provided, which is contrasted by an axially elongated through hole <NUM>', provided in the lower plastic half-shell <NUM>.

On one side and on the other side of the widened section <NUM> respective recesses <NUM>, <NUM> are provided, at which respective horizontal edges <NUM>, <NUM> are provided, extending for at least part of the length of the recesses, with which they go to engage respective hook sections of shorter length <NUM>, <NUM> of the lower half-shell <NUM>, with the possibility of sliding on said edges <NUM>, <NUM> which act as guide rails. The coupling between the hook sections <NUM>, <NUM> and the edges <NUM>, <NUM> also allows the two half-shells to be held firmly together.

The recess <NUM> of the upper half-shell <NUM>, which is longer than recess <NUM>, ends with a wedge end <NUM>, which develops downwards and is inserted in a cavity <NUM> of an expansion bushing <NUM> made up of two opposing wings <NUM> separated one from the other along a vertical plane and provided externally with indentations <NUM>, developing in a circumferential direction. The two wings <NUM> of the expansion bushing <NUM>, which develop around cavity <NUM>, in resting or non-expanded condition, come into contact at their outermost ends.

Below the recess <NUM>, which is obviously provided at both sides of the upper half-shell <NUM>, a longitudinal rib <NUM> is provided, centrally, which is inserted in a corresponding groove <NUM> provided in the bottom wall of the lower half-shell <NUM>, so as to constitute additional guide means between the two half-shells.

The other recess <NUM>, also obviously provided at both sides of the upper half-shell <NUM>, ends instead with a substantially cylindrical head <NUM>, appropriately grooved, so as to present a frontal closure disc <NUM> which is connected, by means of opposing chamfered sections <NUM>, to a central vertical wall <NUM> having a step <NUM>.

The peripheral wall of the cylindrical head <NUM> has two lateral, radial, opposed slits <NUM> at said chamfered sections <NUM> connected to two lower longitudinal slits <NUM>, so as to determine said frontal closure disc <NUM> and said vertical wall <NUM>.

Correspondingly, the lower half-shell <NUM> has two divergent tongues <NUM>, with chamfered ends <NUM>, designed to be placed in said grooved head <NUM> of the upper half-shell <NUM>. In particular, the tongues <NUM> are inserted in said longitudinal slits <NUM> and the chamfered ends <NUM> in said radial slits <NUM>, coupling perfectly with the chamfered sections <NUM> of said frontal disc <NUM>.

Before the assembly of the two half-shells <NUM>, <NUM> of the casing <NUM>, the aforementioned cam mechanism <NUM> is interposed between them, which has a lower cylindrical section <NUM>, an upper cylindrical section <NUM>, of slightly larger diameter, and a central section <NUM> projecting radially, determining a cam profile.

The lower section <NUM> is designed to be inserted, with the possibility of axial sliding, in said slotted hole <NUM>' provided on the bottom wall of the lower half-shell <NUM>, while the upper cylindrical section <NUM> goes to be housed without play in the circular hole <NUM> provided in the upper half-shell <NUM>. The central section with cam profile <NUM> is placed instead in a seat <NUM> of the lower half-shell <NUM>, open at both sides, and delimited longitudinally by opposing shoulders <NUM>, <NUM>, against which the cam profile <NUM> acts. If necessary, said shoulders <NUM>, <NUM> can be part of a perforated U-shaped metal plate <NUM>, as shown in the drawings, should it be necessary to stiffen the structure.

In the upper cylindrical section <NUM> a shaped seat <NUM> is provided, designed to accommodate a tool <NUM> (not shown in <FIG>) for the actuation of the cam mechanism as will be described here below.

The shaped seat <NUM> could optionally be replaced by a shaped through hole to allow the actuation of the cam both from above and from below.

In this respect, it should be noted that the terms 'lower' and 'upper' used in this description are referred to the arrangement shown in the drawings, as the joining device may be mounted upside down in the furniture parts to be joined with respect to what is shown, to allow actuation of the cam from below, and therefore in a less visible position.

The assembly of the joining device <NUM> according to the invention takes place simply by assembling the two half-shells <NUM>, <NUM> of the casing <NUM> with the cam mechanism <NUM> interposed between them, which is allowed by the elasticity of the hook sections <NUM>, <NUM> of the lower half-shell <NUM>, which go to snap-engage with the edges <NUM>, <NUM> of the upper half-shell <NUM>.

The functioning of the joining device according to the invention is now illustrated, with particular reference to <FIG>.

In the present description, the front end or part of the device is indicated as that where the flexible tongues <NUM> and the hollow head <NUM> are provided, placed on the right in the drawings, and the rear end or part that where the expansion bushing <NUM> and the wedge-shaped end <NUM> are provided.

<FIG> shows the rest configuration, or non-expanded configuration, of the device with tool <NUM> inserted in seat <NUM> of the cam mechanism <NUM>.

In this configuration, the lower half-shell <NUM> is held in the more backward position, i.e. at the rear end of the casing <NUM>, by the cam profile <NUM> which acts with its most protruding part against the shoulder <NUM> of the seat <NUM> housing the cam mechanism, formed in the lower half-shell <NUM>.

<FIG> shows the final expanded configuration of the joining device of the invention, which is achieved by actuating in rotation the cam mechanism <NUM> by means of tool <NUM> so as to bring the cam profile <NUM> to act against the shoulder <NUM> opposed to the shoulder <NUM>, causing the forward movement of the lower half-shell <NUM>. In the drawings a rotation of <NUM>° clockwise is provided, indicated by the arrows F. On the basis of the shape and arrangement of the cam, however, it would be possible to obtain the same result with a different angle of rotation and/or a rotation in the opposite direction to the previous one.

During the forward movement of the lower half-shell <NUM>, the two tongues <NUM> spread apart, sliding with their chamfered ends <NUM> on the corresponding chamfered sections <NUM> of the frontal disc <NUM> of the hollow head <NUM> of the upper half-shell <NUM>. In this way, the chamfered ends <NUM> of the tongues <NUM>, expanding, determine the locking of the device in one of the two parts of the furniture item to be joined.

At the same time, the two wings <NUM> of the expansion bushing <NUM>, sliding on the wedge-shaped end <NUM> of the upper half-shell <NUM>, spread apart, causing, with their indentations <NUM>, the locking of the upper part of the furniture item to be joined and at the same time exerting a certain traction on the same.

In this way a stable clamping of the parts of the furniture item to be joined is obtained.

<FIG> show an example of furniture item assembled using joining devices <NUM> according to the invention.

<FIG> shows an axonometric view of a furniture item <NUM> comprising two opposite and parallel shoulders <NUM>, and two shelves <NUM> interposed between said opposite shoulders, perpendicular to them and parallel to each other.

In the thickness of the shelves <NUM> slots or pockets <NUM> are formed having the function of housing the joining devices <NUM> of the invention, inserted in said slots or pockets with the rear portion bearing the expansion bushing <NUM> which protrudes externally from said pocket and is designed to fit into a further pocket <NUM> formed in the thickness of the shoulders <NUM>.

As can be seen in <FIG>, in shelves <NUM> holes <NUM> are also provided, formed perpendicularly to the axis of the slots or pockets <NUM> having the function of allowing the insertion of tool <NUM> which couples with the shaped seat <NUM> of the cam mechanism <NUM> to carry out the clamping action.

<FIG> and <FIG> show two enlarged details of a portion of furniture item <NUM> assembled using the joining device of the invention, and in which device <NUM>, inserted in a slot or pocket <NUM> of a shelf <NUM>, is shown in the rest configuration with the expansion bushing <NUM> inserted in the pocket <NUM> of the shoulder <NUM> of the furniture item (detail in <FIG>), and in the final configuration in which the expansion bushing, following the expansion and traction action exerted by the reciprocal sliding between the half-shells <NUM> and <NUM>, carries out the clamping with respect to the walls of pocket <NUM> and, consequently, the rigid and stable connection of shelf <NUM> with respect to shoulder <NUM>.

In fact, during the rotation of the cam mechanism <NUM> the expansion of the tongues <NUM> is imposed with consequent locking of device <NUM> of the slot or pocket <NUM> in shelf <NUM>, and the simultaneous expansion and retraction of the expansion bushing <NUM>, which carries out a clamping action with radial stress with respect to the slot or pocket <NUM> with simultaneous traction stress between the two components of the furniture item, in this way defining a stable clamping between the parts without risk of loosening of the constraint.

The possible disassembly of the furniture item can be carried out by imposing, by means of tool <NUM>, a rotation in the opposite direction to that of the assembly/clamping phase, so as to bring the device into the rest configuration. In this case, if desired, device <NUM> can also be extracted from the slot or pocket <NUM> of the shelf, where it is no longer constrained for the return into non-expanded position of the two opposing tongues <NUM>.

The advantages of the joining device according to the invention are clear from the above, which is practically made up of only three components: the two half-shells <NUM>, <NUM> that form the casing <NUM> and the cam mechanism <NUM> interposed between the two. Optionally, the metal reinforcement plate <NUM> can be provided in the seat <NUM> for housing of the cam mechanism <NUM>.

This constitutes a considerable simplification with respect to the known solutions that required a certain number of components inside the casing of the device in order to be able to achieve the expansion of the respective ends.

Claim 1:
Joining device (<NUM>) for parts of furniture and furnishing accessories, such as shelves, bookcases, drawer units, bed frames, seats and the like, comprising a casing (<NUM>), made of two half-shells (<NUM>, <NUM>), and expansion means (<NUM>, <NUM>; <NUM>) provided at the opposite ends of the casing (<NUM>), suitable for being inserted in corresponding seats (<NUM>, <NUM>) of the two parts to be joined to produce locking thereof following the expansion, said expansion means being actuated by a cam mechanism (<NUM>) interposed between said half-shells (<NUM>, <NUM>) of the casing (<NUM>), and pass from a rest, or non-expanded, configuration to an expanded configuration and vice versa, following a relative sliding between said half-shells caused by said cam mechanism (<NUM>), characterised in that said expansion means are an integral part of one of said half-shells, and in that said half-shells are made with materials of different hardness, a first (<NUM>) thereof, bearing said expansion means, being of softer material and having a certain elasticity, so as to snap-fit to a second (<NUM>) of said half-shells.