Patent Description:
This invention relates to a grid assembly, in particular for air distribution systems.

As known, in air distribution systems and, in particular, in controlled mechanical ventilation, grids are commonly used to close the end openings of the conduits in which the air passes.

For example, it is known to use end units consisting of a casing provided with one or more connections to connect to corresponding conduits and an opening closed by a grid.

The grid is commonly fixed to the casing, for example using screws. The use of screws has, however, a negative effect on the aesthetics of the grid.

It is also known to couple the grid to the casing via springs, which project behind the grid and engage corresponding coupling seats in the casing or operate by simple friction/interference. For example, the grid may have two individual springs or two pairs of springs located on opposite sides of the grid.

For example, <CIT> discloses a grating system with a frame upon which a grating can be fixed; a connecting piece can be fixed to the frame that supports a sleeve connectable to an air duct. The frame is provided with a through passage; the through passage in the frame and the periphery of the connecting piece have a complementary shape so that they fit tightly on each other. The frame has notches which issue into the through passage and the connecting piece has projections which snap-engage into the notches.

<CIT> discloses a grill assembly for a duct fan unit comprising a square or rectangular grill mounted on a circular mounting plate so that the grill is rotatable relative to the mounting plate. The grill has a circular mounting structure having a hook designed to fit over the rim of the mounting plate. The grill is provided with flexible clips that hook over the rim and spring back to hold the grill onto the plate but still permits the grill to be rotated relative to the mounting plate. Upon aligning the grill, screws are used to prevent the grill from moving.

<CIT> discloses a ventilation equipment comprising a body having a fan motor and a fan, and a decorative panel that is detachably mounted to the front of the body. An engagement claw is provided at the decorative panel and extends to the rear side to engage a mounting opening in the body.

The known coupling devices of the type now recalled are not completely satisfactory, firstly because they may prove not to be fully reliable in keeping the grid coupled. Because of this, a safety cable that is hooked between the grid and the inner casing, so as to avoid the grid from detaching and falling, is sometimes provided (especially in ceiling installations).

Even the disassembly of the grid for any cleaning and/or maintenance operations may be relatively complicated, because the springs are not easily accessible or operable.

The known coupling devices may also be relatively complex to produce, in particular due to the need to equip the grid with suitably shaped and arranged springs.

In addition, if a filter is joined to the grid, it may be relatively difficult and complicated to mount the filter on the grid, just like accessing the filter for cleaning, maintenance, and replacement operations.

This invention proposes to overcome the drawbacks of the prior art highlighted here, in a particularly simple and efficient way.

In particular, the invention proposes the purpose of providing a grid assembly, in particular for air distribution systems, which makes it possible to simply, but at the same time completely reliably, couple the grid, without requiring safety cables and without the use of visible screws on the front of the grid.

This invention thus relates to a grid assembly, in particular for air distribution systems, as defined in claim <NUM> below.

Preferred features of the invention are defined in the dependent claims.

The invention makes it possible to couple the grid in a simple and fast, but at the same time completely reliable, way, avoiding the need to use safety cables.

The assembly and disassembly of the grid are, in addition, particularly simple and fast.

The grid assembly of the invention is, in addition, very simple to produce.

In preferred embodiments, the grid assembly of the invention is also equipped with a filter, which is, in turn, easily assembled and disassembled.

Additional features and advantages of this invention will be clear from the description that follows of a nonlimiting embodiment, with reference to the attached figures, in which:.

<FIG> indicates as a whole, with reference number <NUM>, a grid assembly, in particular for air distribution systems such as, for example, the so-called controlled mechanical ventilation systems.

The grid assembly <NUM> comprises a casing <NUM>, a grid <NUM>, a mounting frame <NUM>, a coupling device <NUM> for coupling the grid <NUM> to the frame <NUM> and, optionally, a filter <NUM>.

The casing <NUM> is normally intended to be encased in a wall or ceiling or another fixed structure and may have various shapes and dimensions. In general, the casing <NUM> is basically box shaped and has a front opening <NUM> and one or more joint mouths <NUM> for connecting to respective air conduits (not illustrated).

The casing <NUM> is provided with fastening seats <NUM>, for example placed at respective vertices of the opening <NUM> inside of the casing <NUM> and shaped to receive, as will be better described below, respective screws or couplings of another kind, for example snap couplings.

The grid <NUM> is placed opposite the opening <NUM> of the casing <NUM> to close the opening <NUM>.

In the example illustrated, but not necessarily, the grid <NUM> is polygonal, in particular rectangular, but it remains understood that the grid <NUM> may have a different shape.

With reference to <FIG> as well, the grid <NUM> comprises a plate-shaped body <NUM> equipped with a central grid portion <NUM> (which may be variously shaped, also for aesthetic requirements), and an inner edge <NUM>, folded back and orthogonal in relation to the plate body <NUM> and arranged around the plate body <NUM>.

In particular, the edge <NUM> comprises a pair of portions <NUM>, <NUM> that are opposite and facing one another. The portion <NUM> is provided with a contact surface <NUM>, facing the opposite portion <NUM>; the portion <NUM> has a series of undercut teeth <NUM> that project from the portion <NUM> of the edge <NUM> towards the opposite portion <NUM>. The teeth <NUM> are spaced apart from each other along the portion <NUM> and extend perpendicular to the edge <NUM>.

Optionally, the edge <NUM> comprises side teeth <NUM>, which project from respective side portions <NUM> of the edge <NUM>, orthogonal to the portions <NUM>, <NUM>. The teeth <NUM> extend towards each other perpendicular to the edge <NUM>.

Advantageously, the grid <NUM> consists of a single, monolithic piece, for example made of metal or polymer, formed by the plate body <NUM> and by the edge <NUM> with the teeth <NUM> (and any other teeth <NUM>).

With reference to <FIG> as well, the mounting frame <NUM> has a generally polygonal shape, for example, but not necessarily, basically rectangular, and is formed from multiple sides <NUM> joined to each other and delimiting a central opening <NUM>.

The frame <NUM> has an inner perimetric edge <NUM>, which delimits the central opening <NUM>, and an outer perimetric edge <NUM>.

The frame <NUM> is provided with fastening members <NUM> for fastening the frame <NUM> to the casing <NUM>.

In particular, the fastening members <NUM> comprise a plurality of through eyelets <NUM>, formed in the frame <NUM> and shaped to receive respective screws (not illustrated) that engage, in use, respective fastening seats <NUM> formed in the casing <NUM>.

The eyelets <NUM> are preferably longitudinally elongated and inclined with respect to the sides <NUM> of the frame <NUM> and are positioned at respective vertices of the frame <NUM> along the edge <NUM>.

Advantageously, the frame <NUM> consists of a monolithic piece, for example made of polymer.

The grid <NUM> is removably coupled to the frame <NUM> using the coupling device <NUM>.

With reference to <FIG> as well, the coupling device <NUM> comprises at least one pair of elastic coupling springs <NUM> that project from one first side 21a of the frame <NUM> and cooperate with the portion <NUM> of the inner edge <NUM> of the grid <NUM> and, specifically, with the contact surface <NUM>; and the undercut teeth <NUM> that project from the portion <NUM> of the edge <NUM> and engage respective coupling seats <NUM> formed on a second side 21b of the frame <NUM> opposite the first side 21a that carries the springs <NUM>.

In particular, the springs <NUM> are defined by respective flexible projections <NUM> that project from the outside perimetric edge <NUM> of the frame <NUM> and protrude, undeformed, beyond the edge <NUM>.

The springs <NUM> have respective roots <NUM> joined at the edge <NUM> and defining respective elastic hinges, and respective free ends <NUM> facing each other.

The springs <NUM> face respective recesses <NUM> formed in the edge <NUM> and shaped to receive the springs <NUM> when the springs <NUM> are pressed towards the edge <NUM> and elastically deformed in the recesses <NUM>.

The springs <NUM> have respective contact surfaces <NUM> cooperating with the contact surface <NUM> of the portion <NUM> of the inner edge <NUM> of the grid <NUM>; preferably, the contact surfaces <NUM> are curved surfaces and, in particular, convex surfaces.

In the preferred embodiment illustrated, the springs <NUM> are basically S-shaped.

The coupling seats <NUM> have respective inclined sliding surfaces <NUM> cooperating with respective teeth <NUM> of the grid <NUM>.

Optionally, the coupling device <NUM> also includes the teeth <NUM>, which project from the side portions <NUM> of the inner edge <NUM> of the grid <NUM> and engage respective side coupling seats <NUM> formed on respective, opposite additional sides 21c, 21d, orthogonal to the sides 21a, 21b of the frame <NUM>.

The coupling seats <NUM> preferably have respective lateral mouths <NUM>, facing outside, and respective sliding surfaces <NUM>, slanted along the sides 21c, 21d.

The filter <NUM> is placed inside the grid <NUM> and comprises a filter-holder <NUM>, removably fixed to the frame <NUM>, and a filtering sheet <NUM> supported by the filter-holder <NUM> and made of a suitable (known) filtering material.

As illustrated in more detail in <FIG>, the filter-holder <NUM> consists of a grating element <NUM>, having a peripheral frame <NUM> and ribs <NUM> positioned inside the peripheral frame <NUM> and delimiting a plurality of open zones <NUM>.

The filter-holder <NUM> is provided with snap-on coupling members <NUM> to couple with the frame <NUM>.

In particular, the filter-holder <NUM> is provided with a plurality of snap-on coupling members <NUM> positioned along the peripheral frame <NUM> and that project from the peripheral frame <NUM> and are shaped to engage respective seats <NUM> formed on an inner perimetric edge <NUM> of the frame <NUM>. Clearly, the filter-holder <NUM> may include a different number of snap-on coupling members <NUM>, variously shaped and arranged on the peripheral frame <NUM>.

The filter-holder <NUM> is provided with a plurality of contact elements <NUM> laterally projecting from the peripheral frame <NUM> and shaped to rest against an annular front surface <NUM> of the frame <NUM>; and with hooking members <NUM> to hook the filtering sheet <NUM>.

The filtering sheet <NUM> rests on the ribs <NUM> and is held on the filter-holder <NUM> by the hooking members <NUM>.

In use, to assemble the grid assembly <NUM> on the casing <NUM> (however it is installed, for example encased in the wall or ceiling), the frame <NUM> is first fastened to the casing <NUM>, using the fastening members <NUM>, i.e. by inserting respective screws through the eyelets <NUM> and, thus, in the fastening seats <NUM>.

Successively, the filter <NUM>, formed by the filter-holder <NUM> and by the filtering sheet <NUM>, is assembled and fastened to the frame <NUM> via the snap-on coupling members <NUM>.

Finally, the grid <NUM> is mounted: the portion <NUM> of the edge <NUM> is placed on the side 21a of the frame <NUM> in contact with the springs <NUM>; thus, by moving the grid <NUM> towards the side 21b of the frame <NUM>, the springs <NUM> are pushed into the corresponding recesses <NUM>; thus, the teeth <NUM> are brought to engage the respective coupling seats <NUM>. In this way, the grid <NUM> remains locked on the frame <NUM>.

Claim 1:
A grid assembly (<NUM>), in particular for air distribution systems, comprising a substantially box-shaped casing (<NUM>) having a front opening (<NUM>) and one or more joint mouths (<NUM>) for connection to respective air conduits; a grid (<NUM>) positioned in front of the front opening (<NUM>) of the casing (<NUM>) to close said opening (<NUM>); a mounting frame (<NUM>) provided with fastening members (<NUM>) to fix the frame (<NUM>) to the casing (<NUM>); and a coupling device (<NUM>) for coupling the grid (<NUM>) to the frame (<NUM>); wherein the coupling device (<NUM>) comprises at least a pair of elastic coupling springs (<NUM>) which project from a first side (21a) of the frame (<NUM>) and cooperate with a first portion (<NUM>) of an inner edge (<NUM>) of the grid (<NUM>), and one or more undercut teeth (<NUM>) projecting from a second portion (<NUM>) of the inner edge (<NUM>) of the grid (<NUM>), opposite to the first portion (<NUM>), and engaging respective coupling seats (<NUM>) formed on a second side (21b), opposite to the first side (21a), of the frame (<NUM>); and wherein the springs (<NUM>) are defined by respective projections (<NUM>) which project from an outer perimetric edge (<NUM>) of the frame (<NUM>) and protrude, in undeformed conditions, beyond said outer perimetric edge (<NUM>) of the frame (<NUM>); and wherein the springs (<NUM>) face respective recesses (<NUM>) formed in the outer perimetric edge (<NUM>) of the frame (<NUM>) and shaped to receive the springs (<NUM>) following an elastic deformation thereof.