Patent Description:
Trigger dispensing devices are enormously popular today; several hundred million units are manufactured and sold each year.

Traditionally, once the bottle has been filled with the product and the dispensing head has been applied to the bottle, the devices are placed in specially sized cardboard boxes so that they may safely travel to storage or sales locations. In particular, despite loading and unloading from the transport and storage means, the boxes ensure that the devices are not subject to shocks that could compromise their functionality or cause product spillage. Further, the placement of individual devices on supermarket shelves is also done by attentive staff and generally with great care.

For some years now, online commerce has been widely used by consumers for the purchase of food, detergents, and every other kind of merchandise. The widespread use of these sales methods has manifested new needs and raised new issues for the trigger dispensing device industry as well.

In fact, it is quite common for said devices to be stored in less than optimal conditions, or for a device to be shipped to the consumer in a standard-sized box that is larger than said device, or for other goods, such as a book or other bottles, to be placed in the same box.

During transport, the device is subjected to impacts and crushing, which may lead to the breakage of components such as the trigger or the shell, disassembly, undesired activation of the trigger and, often, to product leakage.

One of the drawbacks encountered is the leakage of product through the venting duct, which usually places the internal compartment of the bottle in communication with the external environment, necessary for the entry of air into the bottle during the suction step, while the product is suctioned from the bottle towards the pressure chamber.

<CIT> discloses a liquid ejecting apparatus for liquid substances.

It is the object of this invention to make a trigger dispensing head which meets the aforesaid requirements and overcomes the drawbacks mentioned above.

This object is achieved by a dispensing head according to claim <NUM>. The dependent claims disclose further advantageous embodiments of the invention.

The features and advantages of the dispensing head according to this invention will be apparent from the description below, given by way of non-limiting example in accordance with the figures in the appended drawings, wherein:.

With reference to the figures of the appended drawings, a trigger dispensing device comprising a bottle <NUM> for containing a liquid product to be dispensed and a trigger dispensing head <NUM> applied to a neck 2a of the bottle have been collectively referred to as <NUM>. The neck 2a has a neck axis X.

The head <NUM> is applicable to the bottle <NUM> by means of a ferrule system comprising a threaded ferrule <NUM> which may be screwed to the neck 2a or, according to a variant embodiment, by means of a bayonet system (not shown), preferably equipped with an anti-removal ridge.

The head <NUM> comprises a frame <NUM>, preferably made in one piece of plastic material, for example by injection molding, adapted to support the components of the head <NUM>.

The frame <NUM> comprises an attachment portion <NUM> provided with a main opening 12a having an attachment axis Z; when the head <NUM> is applied to the neck 2a, the main opening 12a is in communication with the compartment inside the neck 2a, and the attachment axis Z is coincident with the neck axis X.

The head <NUM> also comprises a cylinder chamber <NUM>, of cylindrical circular shape, for example having a chamber axis K orthogonal to the attachment axis Z; preferably, the cylinder chamber <NUM> is formed in the frame <NUM>.

The head <NUM> further comprises a suction duct that connects the main opening 12a with the cylinder chamber <NUM>.

Preferably, said suction duct comprises a first suction segment <NUM> which, starting from the main opening 12a, extends along a first suction axis W, parallel to and preferably spaced apart from the attachment axis Z, and a second suction segment <NUM> which flows into the cylinder chamber <NUM> and extends along a second suction axis Y, parallel to the chamber axis K; for example, the second suction axis Y is coincident with the chamber axis K. The second suction segment <NUM> is delimited by a suction mouth 18a.

Preferably, moreover, the first suction segment <NUM> and/or the second suction segment <NUM> are formed in the frame <NUM>.

The head <NUM> further comprises a dispensing duct that places the cylinder chamber <NUM> in communication with the external environment.

Preferably, the dispensing duct comprises a first dispensing section <NUM> which, starting from the cylinder chamber <NUM>, extends along a first suction axis J incident, for example orthogonal, to the chamber axis K, and a second dispensing section <NUM> which opens into the external environment and extends along a second dispensing axis Q parallel to the chamber axis K.

Preferably, moreover, the first dispensing segment <NUM> and/or the second dispensing segment <NUM> are formed in the frame <NUM>.

Preferably, the dispensing head <NUM> further comprises a nozzle <NUM>, applied to the free end of the second dispensing section <NUM>, preferably rotatable at least between a dispensing position, in which the second dispensing section <NUM> is in communication with the external environment, and a closed position, in which fluid communication between the second dispensing section <NUM> and the external environment is prevented.

Preferably, the first dispensing section <NUM> is positioned in a rear region of the dispensing head <NUM>, and the nozzle <NUM> is positioned in a front region of the dispensing head <NUM>.

The dispensing head <NUM> further comprises a cylinder wall <NUM>, having an internal surface 24b which annularly delimits the cylinder chamber <NUM>. In the cylinder wall <NUM>, a main vent passage <NUM> is formed which places the main opening 12a in communication with the cylinder chamber <NUM>, and in particular with the internal surface 24b.

Preferably, the cylinder chamber <NUM> is delimited at the bottom by a bottom wall <NUM>, for example from which the suction mouth 18a of the suction duct projects, and in particular the second suction section <NUM>.

The head <NUM> further comprises a sleeve <NUM>, inserted in the cylinder chamber <NUM>.

According to an embodiment, the sleeve <NUM> is inserted into the cylinder chamber <NUM> in a fixed angular position, i.e. constrained to rotation around the chamber axis K.

According to a different embodiment (not shown), the sleeve <NUM> is rotatably coupled in the cylinder chamber <NUM>, i.e. it is free to rotate around the chamber axis K.

The sleeve <NUM> comprises a cylindrical sleeve wall <NUM> having an external surface 32a and an internal surface 32b.

The dispensing head <NUM> further comprises a labyrinth seal <NUM>, suitable for placing the main vent passage <NUM> in communication with the external environment.

In particular, one of the external surface 32a of the sleeve <NUM> and the internal surface 24b of the cylinder chamber <NUM> comprises a labyrinth seal <NUM> suitable for placing the main vent passage <NUM> in communication with the external environment.

According to an embodiment, the labyrinth seal <NUM> is on the external surface 32a of the sleeve <NUM>.

According to a different embodiment (not shown), the labyrinth seal <NUM> is on the internal surface 24b of the cylinder chamber <NUM>.

Preferably, the labyrinth seal <NUM> comprises a channel <NUM>', suitable for placing the main vent passage <NUM> in communication with the external environment. For example, the channel <NUM>' has a circumferential or spiral extension. In an embodiment variant (not shown), the channel <NUM>' is linear and curvilinear, for example linear in sections.

Furthermore, the sleeve <NUM> preferably comprises a continuous ridge <NUM> which laterally defines the channel <NUM>'. In particular, said continuous ridge <NUM> is positioned in contact with the internal surface 24b, thus creating a seal against product leakage.

In other words, the labyrinth seal <NUM> is shaped to provide a tortuous path suitable for placing the external environment in fluid connection with the main vent passage <NUM>. In fact, the air may be drawn back, for example as a result of a depression, towards an internal compartment of the bottle <NUM> through the channel <NUM>'; however, a small quantity of liquid that comes out of the main vent passage <NUM> may not go entirely through the channel <NUM>' and exit outside the dispensing head <NUM>. In particular, the continuous ridge <NUM> forces the liquid to continue along the channel <NUM>', hindering the leakage, since it forms a meatus with the internal surface 24b.

According to an embodiment, the sleeve <NUM> comprises at least one circumferential sealing ridge 42a, projecting from the external surface 32a and positioned in contact with the internal surface 24b, creating a seal against product leakage therewith.

For example, the sleeve <NUM> comprises two axially spaced circumferential sealing ridges 42a, preferably side by side with and axially spaced from the labyrinth seal <NUM>.

Preferably, moreover, the cylinder wall <NUM> comprises at least one circumferential sealing ridge formed in the internal surface at said at least one circumferential sealing ridge 42a, collaborating with this to provide a seal against product leakage.

For example, the cylinder wall <NUM> comprises two circumferential sealing ridges positioned at two circumferential sealing ridges 42a.

Preferably, the sleeve <NUM> further has a secondary vent passage <NUM> passing through the sleeve wall <NUM>, which surfaces on the external surface 32a. The secondary vent passage <NUM> is suitable for placing the main vent passage <NUM> in communication with the external environment.

Preferably, the secondary vent passage <NUM> is positioned between the labyrinth seal <NUM> and a circumferential sealing ridge 42a.

Preferably, moreover, at a first axial end <NUM>' of the sleeve wall <NUM>, the sleeve wall <NUM> defines a head opening <NUM> of the sleeve <NUM>, delimited by a sleeve edge 33a.

According to an embodiment, at a second axial end <NUM>'' from the sleeve wall <NUM> opposite the first axial end <NUM>', the sleeve <NUM> comprises a bottom wall <NUM> incident, for example orthogonal, to the chamber axis K.

According to an embodiment, at the second axial end <NUM>'', the sleeve <NUM> comprises an annular end wall <NUM> projecting axially from the bottom wall <NUM>, which defines a bottom opening <NUM> of the sleeve <NUM>.

Preferably, said end wall <NUM> is radially lowered with respect to the sleeve wall <NUM>.

The suction duct opens into the sleeve <NUM> through the bottom opening <NUM>; in particular, the second suction section <NUM> opens into the sleeve <NUM>, for example into the compartment <NUM> delimited by the end wall <NUM>.

Preferably, the external surface 32a of the sleeve wall <NUM> has a converging truncated conical shape, for example converging at the rear. Preferably, moreover, also a sealing portion 245b of the internal surface 24b has a truncated conical shape. For example, said sealing portion 245b collaborates with the labyrinth seal <NUM> to make a seal against product leakage.

According to an embodiment, the sleeve <NUM> comprises a bottom lip <NUM> which extends circumferentially, positioned at the second axial end <NUM>'' of the sleeve wall <NUM>, for example projecting axially with respect to the sleeve wall <NUM>.

Preferably, the bottom lip <NUM> has the shape of an annular crown.

Said bottom lip <NUM> is suitable for sealing the internal surface 24b which delimits the cylinder chamber <NUM>, for example by elastically deforming radially towards the inside, to prevent leakage from the valve compartment <NUM>' towards the cylinder chamber <NUM> and towards the external environment.

The bottom lip <NUM> is made in one piece with the sleeve <NUM>, in particular with the sleeve wall <NUM> or the bottom wall <NUM>, for example it is made of polypropylene PP.

Preferably, the bottom lip <NUM> is joined to the external surface 32a.

In particular, with the sleeve <NUM> mounted in the cylinder chamber <NUM>, the bottom lip <NUM> faces, preferably projects, into the valve compartment <NUM>'.

According to an embodiment, the bottom lip <NUM> extends radially in a divergent manner. That is, the bottom lip <NUM> is flared outwardly.

According to a different embodiment, the sleeve <NUM> comprises a sealing ring <NUM> which extends circumferentially, made by bi-injection integrally with the sleeve <NUM> and connected to the sleeve wall <NUM>, preferably at the second axial end <NUM>''.

In particular, the sealing ring <NUM> is made of a material particularly suitable for sealing the internal surface 24b to prevent leakage from the valve compartment <NUM>' towards the cylinder chamber <NUM> and towards the external environment.

According to an embodiment, the sleeve <NUM> is made of a first rigid material, to make the pressure chamber 30a, for example polypropylene, and the sealing ring <NUM> is made of a second material at least partially elastically deformable, for example low density polyethylene LDPE.

In order to further improve the seal, the sealing ring <NUM> preferably comprises a thickened portion <NUM> adapted to deform elastically by sealingly engaging the internal surface 24b.

Preferably, with the sleeve <NUM> mounted in the cylinder chamber <NUM>, the sealing ring <NUM> faces the valve compartment <NUM>'.

Preferably, the sealing ring <NUM> is joined to the external surface 32a.

The head <NUM> further comprises a manually operable piston <NUM> for translating between an initial rest position and a final end-of-stroke position. The sleeve annularly defines a pressure chamber 30a, in which said piston <NUM> operates.

The piston <NUM> is inserted into the sleeve <NUM> through the head opening <NUM> and sealingly slides within said sleeve <NUM>.

Preferably, the piston <NUM> is made in one piece of plastic material, obtained for example by injection molding.

The preferably hollow piston <NUM> comprises an annular piston wall <NUM> extending along a piston axis P between a front end <NUM> and a rear end <NUM>.

Preferably, the piston <NUM> comprises a piston bottom <NUM> at the front end <NUM>. At the rear end <NUM>, the piston <NUM> has a piston coupling portion <NUM> for coupling to a trigger of the head <NUM>, provided for example with holes <NUM>.

Preferably, the piston <NUM> comprises a circumferential main piston seal <NUM> and a secondary piston seal <NUM>, projecting externally from the piston wall <NUM>. In particular, inside the sleeve <NUM>, the main piston seal <NUM> axially delimits the pressure chamber 30a together with the bottom wall <NUM> where the suction duct opens, and in particular the second suction section <NUM>.

Preferably, the secondary vent passage <NUM> is open on the internal surface 32b of the sleeve <NUM> and between the main piston seal <NUM> and the secondary piston seal <NUM>, in the initial rest position of the piston <NUM>.

Preferably, at least one through connection opening <NUM> having a circumferential pattern is formed in the cylinder wall <NUM>, for example a pair of diametrically opposite connection openings <NUM>. For example, the connection opening <NUM> is peripherally defined by connection opening edges <NUM>.

Furthermore, the sleeve <NUM> comprises at least one connection member <NUM>, for example a pair of connection members <NUM>, projecting radially from the external surface 32a. Said at least one connection member <NUM> is housed in the connection opening <NUM>, making a shape coupling with this, to constrain the sleeve <NUM> in the cylinder chamber <NUM>.

Preferably, the connection member <NUM> comprises a central slide <NUM> snapped into the connection opening <NUM>, for example during the operations of inserting the sleeve <NUM> into the cylinder chamber <NUM>, axially constraining the sleeve <NUM> into the cylinder chamber <NUM>.

Preferably, the central slide <NUM> comprises a central step <NUM>' facing forward, adapted to axially abut the connection opening edges <NUM> which define the connection opening <NUM>.

In other words, the central slide <NUM> is axially inclined, for example converging towards the end wall <NUM>.

Preferably, moreover, the connection member <NUM> comprises a pair of circumferential portions <NUM> having a circumferential extension substantially equal to the circumferential extension of the connection opening <NUM> in which they are housed, angularly constraining the sleeve <NUM> in the cylinder chamber <NUM>.

Preferably, moreover, the connection member <NUM> comprises a pair of auxiliary slides <NUM> placed side by side with the central slide <NUM>, for example angularly spaced from said central slide <NUM>, thereby defining a pair of slide compartments <NUM>.

Preferably, the auxiliary slides <NUM> are positioned at the circumferential portions <NUM>.

In a first embodiment, the auxiliary slides <NUM> are at least partially inclined parallel to the central slide <NUM>.

In a second embodiment, the auxiliary slides <NUM> are at least partially inclined circumferentially.

In a third embodiment, the auxiliary slides <NUM> are at least partially inclined both axially, i.e. parallel to the central slide <NUM>, and at least partially inclined circumferentially.

Preferably, the cylinder chamber <NUM> has a variation in diameter which determines an annular space <NUM> with a larger diameter. Furthermore, the sleeve <NUM> comprises at least one axial rib <NUM> projecting radially from the external surface 32a which is housed in said annular compartment <NUM>.

Preferably, the cylinder wall <NUM> comprises a step <NUM>, at the variation in diameter, and a compartment wall <NUM> which annularly delimits said annular compartment <NUM>.

In one embodiment, the at least one connection opening <NUM> is made in the compartment wall <NUM>.

Preferably, the sleeve <NUM> comprises a plurality of angularly spaced axial ribs <NUM>, positioned circumferentially between two connection members <NUM>.

The head <NUM> further comprises a trigger <NUM>, comprising a lever actuation portion <NUM> suitable for positioning the user's fingers for actuating the head <NUM>, and a trigger engagement portion <NUM> for connecting with the piston <NUM>. For example, the trigger <NUM> is hinged to the piston <NUM>, for example by engagement of the trigger engagement portion <NUM> with the piston engagement portion <NUM> of the piston <NUM>.

Preferably, the head <NUM> also comprises elastic return means suitable for operating permanently on the piston <NUM>, directly or indirectly, to bring it to an initial position, which will be discussed later. For example, said return means comprise at least one flexible element <NUM>, preferably a pair of flexible elements, made in one piece with the actuation portion <NUM> of the trigger <NUM>.

Preferably, a valve compartment <NUM>' is defined between the sleeve <NUM>, the cylinder wall <NUM> and the bottom wall <NUM>.

Preferably, the valve compartment <NUM>' has an annular shape radially around the end wall <NUM>.

The head <NUM> further comprises valve means suitable for regulating the flow of product from the suction duct to the pressure chamber 30a and from the pressure chamber 30a to the dispensing duct. Said valve means are accommodated in the valve compartment <NUM>'.

Preferably, said valve means comprise an at least partially flexible valve element <NUM>, made in a single piece, for example by injection molding.

According to an embodiment, the valve element <NUM> comprises a tubular portion <NUM> consisting of an annular valve wall <NUM> extending along a valve axis V, between a rear end <NUM> which defines a rear opening <NUM>, and a front end <NUM>.

The valve element <NUM> further comprises a flexible flap <NUM> connected in a cantilevered manner to the front end <NUM> of the valve wall <NUM>, projecting radially internally.

The flap <NUM> has, from the side facing the rear opening <NUM>, a shutter portion <NUM>, for example flat or hemispherical or truncated-cone shape.

The valve element <NUM> further comprises an annular membrane <NUM> that extends radially externally from the tubular portion <NUM>. The membrane <NUM> is, for example, concave on the side facing the front end <NUM> of the tubular portion <NUM>, or according to further variants (not shown), the membrane <NUM> is flat or convex on the side facing the front end <NUM> of the tubular portion <NUM>.

The valve element <NUM> further comprises a support portion <NUM> composed of an annular support wall <NUM> that connects to and surrounds the membrane <NUM>.

Preferably, the membrane <NUM> extends in a radial direction beyond the end wall <NUM>.

Preferably, the support wall <NUM> has a flared shape toward the front end <NUM> of the tubular portion <NUM> and, on the part facing the rear end <NUM>, a wavy valve base <NUM> that forms a support for the valve element.

The valve element <NUM> is located in the cylinder chamber <NUM>, against the bottom wall <NUM>, against which the valve base <NUM> is placed; the support wall <NUM>, on the other hand, is in contact with the cylinder wall <NUM> and creates a seal against product leakage.

The tubular portion <NUM> is threaded onto the suction duct, and in particular onto the second suction segment <NUM>, and the flap <NUM> forms a flexible shutter for said suction duct. The suction mouth 18a of the suction duct and the flexible flap <NUM> form suitable suction valve means for allowing product to pass from the suction duct to the pressure chamber 30a in a suction step and preventing product from passing from the pressure chamber 30a to the suction duct in a dispensing step.

The membrane <NUM> cooperates with the sleeve <NUM>, and in particular closes the bottom opening <NUM> of the pressure chamber 30a and abuts against the end wall <NUM>. The end wall <NUM> and the membrane <NUM> form pre-compression valve means suitable to allow product to pass from the pressure chamber 30a to the dispensing duct only when the pressure in the pressure chamber 30a exceeds a predetermined threshold value. Said pre-compression valves are also suitable for preventing the product from passing from the dispensing duct to the pressure chamber 30a during a suction step.

The valve element <NUM>, cooperating with the suction mouth 18a of the suction duct and the end wall <NUM> of the sleeve, thus integrates both the suction valve means and the pre-compression valve means into a single component.

In normal operation of the trigger dispensing device, the head <NUM> is applied to the bottle <NUM>, so that the suction duct is in communication with the compartment inside the bottle <NUM> through the main opening 12a.

Preferably, in an initial configuration in which the trigger <NUM> and the piston <NUM> are in a respective initial rest position (<FIG>), the pre-compression valve means and the valve suction means are in a respective closed configuration.

Furthermore, preferably, in the initial configuration, the secondary vent passage <NUM> is axially included between the main piston seal <NUM> and the secondary piston seal <NUM> of the piston <NUM>.

Furthermore, preferably, in the initial configuration, the main vent passage <NUM> is fluidically isolated from the external environment.

By actuating the trigger <NUM>, the axial translation of the piston <NUM> occurs, said piston moving within the sleeve <NUM> and putting pressure on the product contained in the pressure chamber 30a.

Preferably, as long as the secondary piston seal <NUM> is positioned beyond the secondary vent passage <NUM>, the secondary vent passage <NUM> is in fluid communication with the external environment.

Once a predefined threshold pressure in the pressure chamber 30a has been exceeded, the pre-compression valve means switch to an open configuration in which they allow the passage of the product from the pressure chamber 30a to the dispensing duct (<FIG>).

Specifically, the membrane <NUM> separates from the end wall <NUM> of the sleeve <NUM> and allows the product to pass to the dispensing duct, allowing it to be dispensed externally through the nozzle <NUM> (dispensing step). The suction valve means remain in the closed configuration.

Once the trigger <NUM> and the piston <NUM> have reached the end-of-stroke position (<FIG>) and the dispensing step has finished, the trigger <NUM> is released and the elastic return means operates to return the piston <NUM> and the trigger <NUM> to the initial rest position.

The return of the piston <NUM> towards the initial rest position causes a depression in the pressure chamber 30a, which causes the switching of the suction valve means to an open configuration in which they allow the suction of the product from the suction duct into the pressure chamber 30a (<FIG>).

In particular, the membrane <NUM> bends and detaches from the suction mouth 18a of the suction duct, allowing the product to pass from the suction duct into the pressure chamber 30a (suction step).

Furthermore, in the suction step, the internal compartment of the bottle is in communication with the external environment through the secondary vent passage <NUM>, the channel <NUM>' of the labyrinth seal <NUM> and the main vent passage <NUM>.

According to a different embodiment, the valve element <NUM> comprises the annular valve wall <NUM> and an engagement wall <NUM> projecting from the membrane <NUM> along the valve axis V, for example concentric to the annular valve wall <NUM>.

Preferably, the engagement wall <NUM> has an external engagement surface 260a having at least one end zone, distal from the membrane <NUM>, flared outwards.

In addition, the end wall <NUM> of the sleeve <NUM> comprises an internal end surface 36a facing the compartment <NUM> delimited by the end wall <NUM>.

In particular, the internal end surface 36a comprises a first portion 36a' axially ending with the bottom opening <NUM>, and a second portion 36a'' connected to the first portion 36a', for example of a truncated conical shape, ending at the base of the end wall <NUM>, i.e. proximal to the bottom wall <NUM>.

Cooperating with the internal end surface 36a of the end wall <NUM>, the engagement wall <NUM> forms pre-compression valve means suitable to allow product to pass from the pressure chamber 30a to the dispensing duct only when the pressure in the pressure chamber 30a exceeds a predetermined threshold value.

In an initial configuration of the trigger <NUM>, the engagement wall <NUM>, preferably the flared end zone thereof, is in contact with the internal end surface 36a, preferably the second portion 36a'' thereof.

The sliding of the piston <NUM> generates a progressive increase in pressure in the pressure chamber 30a, causing the elastic deformation of the membrane <NUM> and the sliding of the engagement wall <NUM> along the internal end surface 36a, in the direction of the bottom wall <NUM>. In this step, the pressurized product to be dispensed enters at least in part into the compartment <NUM>.

Once a predefined threshold pressure in the pressure chamber 30a has been exceeded, for example the first portion 36a' has been reached, the engagement wall <NUM> allows the product to leave the compartment <NUM> and flow towards the valve compartment <NUM>' (dispensing step).

For this purpose, for example, the end wall <NUM> has an inlet window <NUM> passing radially and open in the first portion 36a'.

In the embodiment of <FIG>, the flexible flap <NUM> is replaced by a notch (not shown) in the valve wall <NUM>, defined between separable lips to allow the passage of product towards the pressure chamber 30a (suction step).

Further details on the operation of the pre-compression valve means are described in international applications <CIT> and <CIT> in the name of the Applicant.

According to a preferred embodiment, moreover, the head <NUM> comprises a shell <NUM> attached to the frame <NUM> to cover it. Preferably, the shell <NUM> is applied to the frame <NUM> by at least one snap coupling.

For example, a first snap coupling <NUM> arranged in an upper region of the frame <NUM>, such as above the second dispensing segment <NUM>, and a second snap coupling <NUM>, arranged in a lower region of the frame, for example below the bottom wall <NUM> of the cylinder chamber <NUM>, are provided.

Preferably, moreover, an upper surface <NUM> of the shell <NUM> comprises a flat region <NUM>. Advantageously, said region allows any weight on the device to be better supported, for example during storage in the warehouse, avoiding the detachment of the shell from the frame.

According to an embodiment, moreover, wherein the first dispensing segment <NUM> is formed in the frame <NUM> and extends along the first suction axis J orthogonal to the chamber axis K, the frame <NUM> also has an extension <NUM>' of the first dispensing segment <NUM> along said first suction axis J.

The extension <NUM>' is itself open to the outside in order to allow, during the molding of the frame, the introduction of a core for forming the first dispensing segment <NUM>.

Preferably, the shell <NUM> comprises a cap <NUM>, protruding internally, suitable for closing off access to the outside of the extension <NUM>'.

Innovatively, the dispensing head described above meets the needs of the sector and overcomes the aforementioned drawbacks, since it allows a high seal against possible product leakage.

Advantageously, in fact, in a horizontal or overturned position during transport or storage, a leak of liquid that comes out of the bottle, for example through the main vent passage, runs into numerous sealing portions.

Advantageously, the labyrinth seal creates a tortuous path which considerably reduces and prevents the escape of liquid from the main vent passage.

Advantageously, the sleeve engages the cylinder chamber in a fixed position, and in particular in a fixed angular position, further improving the seal. In fact, as verified by the Applicant, if the sleeve is free to move in the cylinder chamber, it undergoes malfunctions and leaks, with consequent product leakage.

Advantageously, the bottom lip of the sleeve effectively reduces the leakage of product under pressure present in the valve compartment.

Advantageously, the bi-injected sealing ring with the sleeve further improves the seal against product leakage from the valve compartment. In particular, the bi-injected sealing ring achieves a better seal than that provided by the sleeve made of rigid material.

Advantageously, moreover, the piston slides inside the sleeve, which is substantially free of shrinkage after molding; the sliding takes place, therefore, on a surface having a high cylindricity which ensures a better seal.

Claim 1:
A trigger dispensing head (<NUM>) applicable to a bottle (<NUM>) of a trigger dispensing device (<NUM>) for dispensing a product, comprising:
- a frame (<NUM>), suitable for supporting the components of the head (<NUM>), comprising a main opening (12a) in communication with an internal compartment of the bottle (<NUM>);
- a cylinder chamber (<NUM>) annularly delimited by a cylinder wall (<NUM>) having an internal surface (24b), wherein a main vent passage (<NUM>) is obtained in the cylinder wall (<NUM>), putting in communication the main opening (12a) with the internal surface (24b) of the cylinder wall (<NUM>);
- a manually operable piston (<NUM>) for translating between an initial rest position and a final end-of-stroke position;
- a pressure chamber (30a) in which said piston (<NUM>) operates;
- a sleeve (<NUM>), which delimits said pressure chamber (30a), at least partially housed in the cylinder chamber (<NUM>), comprising an annular sleeve wall (<NUM>), which has an external surface (32a) and an internal surface (32b);
- a suction duct suitable for putting the internal compartment of the bottle (<NUM>) in communication with the pressure chamber (30a);
- a dispensing duct suitable for putting the pressure chamber (30a) in communication with the external environment; and
- valve means for adjusting the flow of product from the suction duct to the pressure chamber (30a) during a suction step and from the pressure chamber (30a) to the dispensing duct during a dispensing step;
the trigger dispensing head (<NUM>) being characterized by a labyrinth seal (<NUM>) suitable for putting the main vent passage (<NUM>) in communication with the external environment, obtained on one of the external surface (32a) of the sleeve (<NUM>) and the internal surface (24b) of the cylinder wall (<NUM>).