DESCRIPTION The object of the present invention is a sprayer for liquids, in particular a pump sprayer actuated manually by means of a trigger lever, provided with a system of precompression suitable for expelling the liquid with a greater speed or acceleration.

A sprayer generally comprises a main body provided with a base with a threaded ring nut or with bayonet coupling to be attached to the mouth of a container of liquid, a delivery nozzle wherefrom the liquid is sprayed, a trigger lever which can be actuated by hand by the user and a pump which can be actuated by the trigger lever to aspirate the liquid from the container by means of a dipper tube and spray it via the delivery nozzle. The pump provides a piston acting in a chamber formed in the body of the sprayer. The body of the sprayer comprises moreover an inlet duct which places in communication the interior of the container of the fluid with the chamber of the pump and an outlet duct which places in communication the chamber of the pump with the nozzle of the sprayer. A valve for fluid suction and delivery is provided inside or immediately upstream of the chamber of the pump, suitable for allowing in a selective and one-way manner the suction of the fluid from the container to the chamber of the pump and the delivery of fluid from the chamber of the pump towards the delivery nozzle.

In order to accelerate the exiting of the liquid from the sprayer, or to guarantee a regular jet of the liquid, normally nebulised, aside from the speed of actuation of the trigger lever, systems of precompression have been proposed, which co-operate with the piston actuated by the lever in order to increase the pressure of delivery of the liquid.

These known systems of precompression normally require numerous additional components in order to obtain the desired effect, with consequent increase in the cost of production. They are also somewhat complex and not easy to produce.

WO 02/094708 describes a pump mechanism applied to a batching apparatus suitable for supplying micro doses of medicinal fluid, for example an ophthalmic solution. This pump mechanism comprises a tank for the containing of at least one dose of fluid, a fluid collection chamber in communication with said tank and a dose control portion comprising a volume defined by two dimensions, a first piston suitable for pushing the fluid from the tank to at least one dose control portion, a second piston slidingly placed inside said dose control portion and a nozzle suitable for allowing the exit of the fluid moved by the second piston.

The object of the invention is that of providing a sprayer for liquids with system of precompression which is simple and economical to manufacture and highly reliable. Another object of the invention is that of providing such a system of precompression which can easily be adapted, with few actions, to existing sprayers.

Still yet another object of the invention is that of providing an innovative, simple and reliable system of blocking/unblocking of the delivery of the fluid.

In particular the system of precompression that forms the object of the invention constitutes an improvement of the sprayer for liquids that is the object of the European patent EP 1585602, on the basis of which the preamble of the annexed independent claim 1 was formulated.

The sprayer for liquids with system of precompression which is the object of the invention has the features of the characterising part of the independent claim 1.

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

Substantially, in the outlet duct of the chamber of the pump, a piston is provided, normally held in occlusion of this duct by a precompression spring, the elastic force whereof is overcome by the pressure of the fluid following actuation of the pump, with consequent displacement of the piston and exiting of the fluid.

In this phase the precompression spring acting on said piston exerts an additional pressure on the fluid, which is delivered at a greater speed.

Advantageously the aforesaid piston and the precompression spring are placed in a horizontal channel of said duct of outlet from the chamber of the pump, which leads as far as the nozzle and the piston and is controlled by the pressurised fluid coming from a vertical channel of the outlet duct, in communication with the chamber of the pump. Said piston has the shape of an elongated stem, and has a conical tip suitable for abutting, in non-operative condition of the sprayer, against the delivery nozzle, blocking the passage of the fluid. Moreover said stem piston has a section of surface with cam profile, such that in a position of blocking of the sprayer it occludes the vertical channel of the outlet duct and in a position rotated through a certain angle, for example 90°, frees this channel.

Further features of the invention will be made clearer by the following detailed description, referred to one of its embodiments purely by way of a non-limiting example illustrated in the accompanying drawings, in which:

Fig. 1 is a median sectioned view of a sprayer during the liquid suction phase, with system of precompression according to the invention;

Fig. 2 is a sectioned view taken along line II-II of Fig. 1;

Figure 2a is a perspective view of the detail of the compression spring shown sectioned in Figure 2;

Fig. 3 is a view partially in elevation and partially sectioned along line III-III of Fig. 1; Fig. 4a is an enlargement of the nozzle of the sprayer enclosed in the circle A of Fig. 1; Fig. 4b is a section taken along line IV -IV of Fig. 4a;

Figs. 5, 6 and 7 are similar views to those of Figs. 1, 2 and 3, with the sprayer in phase of delivery of the liquid;

Fig. 8a is an enlargement of the detail denoted by B in Fig. 5, with the sprayer in open position (ON);

Fig. 8b is a section taken along line VIII- VIII of Fig. 8a;

Figs. 9a and 9b are similar views to those of Figs. 8a and 8b, with the sprayer in closed position (OFF).

In the accompanying drawings a structure of sprayer is shown as described in the aforementioned European patent EP 1585602, whereto reference can be made for further details on the functioning of the sprayer, which will only be described in brief here.

The sprayer according to the invention, denoted as a whole by reference numeral 10, comprises a body 11 closed by a closure cap 12. At the base of the body 1 1 of the sprayer an attachment ring nut 15 is rotatably mounted which has internal threading suitable for engaging with the external threading of the mouth of a container (not shown), suitable for containing a liquid, such as for example liquids for cleaning the home. Naturally the attachment of the sprayer on the container may also take place in a different way, for example by means of a bayonet coupling.

The body 11 of the sprayer has a substantially L shape and ends in a delivery nozzle 16 with an opening from which the liquid is delivered.

The delivery nozzle 16 is made up of a hole formed in a spray ring nut 16'.

For the actuation of the sprayer a trigger lever 17 is provided, hinged at one of its ends 18 to the body 11 and in one of its intermediate positions 19 to the stem 20 of a piston or plunger 21, sliding in a chamber 22 of a pump body 23. In the rear wall of the chamber 22 a hole of inlet of the liquid 24 is formed, in communication with the interior of the container via a dipper tube 25, and an outlet hole 26 in communication with the spray nozzle 16, via a substantially L-shaped outlet duct 29, comprising a vertical channel 27 and a horizontal channel 28 ending at said spray nozzle 16.

In the lower part of the vertical channel 27 of the outlet duct 29 a plug 13 is inserted, suitable for preventing the inlet 24 and outlet 26 holes from being in communication one with the other.

The aforesaid inlet and outlet holes for the liquid 24 and 26 are occluded respectively by a dome piece 31 and by a truncated cone body 32 of a one-way suction and delivery valve 30. The functioning of the one-way valve 30, described in greater detail in the aforementioned patent EP 1585602, is fairly intuitive.

By pressing the trigger lever 17, the liquid in the chamber 22 of the pump exerts a pressure against the valve 30, deforming the truncated cone shank 32 and then exiting through the outlet hole 26 to go towards the nozzle 16 (Fig. 5).

When the trigger lever 17 is released and returns into the rest position through the action of elastic means not described, the plunger 21 creates a vacuum in the chamber 22 freeing the inlet hole 24, as shown in Figure 1, making the liquid aspirated from the container flow into the chamber 22. What has been described hitherto is considered prior art from the aforementioned patent EP 1585602.

According to the invention, the sprayer that is the object of the aforementioned European patent, as described hitherto, is equipped with a system of precompression of the liquid placed in the abovementioned outlet duct 29.

More particularly, the aforementioned horizontal channel 28 of the outlet duct 29 is wider than the short vertical channel 27 and extends slightly towards the back, beyond said vertical channel 27, where it has a further widening of diameter 43 and an opening 49. The horizontal channel 28 is therefore open at the rear, at the end opposite to the one where the delivery nozzle 16 is positioned.

A piston 41 is positioned in the horizontal channel 28, sliding with a limited stroke, in the form of an elongated stem appropriately shaped, as will be described in greater detail herein below, carrying at the rear a plunger 44 housed in said widening 43.

The stem piston 41 is inserted in the horizontal channel 28 through said rear opening 49 and extends along the whole length of the horizontal channel 28 ending with a conical tip 45 which abuts, in a non-operational condition of the sprayer, against the hole 16 of the delivery nozzle, occluding it. The piston 41 is pushed constantly in the direction of occlusion of the hole 16 by a spring 42 acting to the rear of the same. In the example shown (see in particular Figs. 2, 2a and 6) the spring 42 is a bellows spring or spring washer hooked to said widening 43 and exerting a thrust on the back of the piston 41.

The spring 42 is formed advantageously in plastic material and is positioned substantially outside of the horizontal channel 28 behind said rear opening 49. It is however clear that any other elastic means can be used to obtain the same result. More particularly the spring 42 comprises a cylindrical shell 60 which is positioned externally around said widened seat 43. From the front of said shell project a pair of opposite teeth 61 which hook with corresponding joined teeth 62 provided externally and integral with said widened seat 43. To the rear of the shell 60, in alignment with said teeth 61 , two extensions 63 are provided, bent into a loop or U shape, which join to form a central plate 64 which goes to abut on the rear of the piston 41. The piston 41 has an intermediate conical section 46 causing a reduction of diameter of the piston in its end part towards the nozzle 16, said conical section 46 being placed at a corresponding conicity 47 provided in said horizontal channel 28. In the rear part of the piston 41 , at the level of said vertical channel 27 of the outlet duct, a cam configuration 50 is provided. In particular two opposite raised surfaces 51, extending each one for an arc of approximately 90°, are provided on the profile of the stem piston

41, alternating with respective furrows 52, corresponding to the diameter of the piston 41. The stem piston 41 can be rotated by rotating the ring nut 16' between a position wherein one of the two raised surfaces 51 is positioned at the vertical channel 27 of the outlet duct 29, preventing the passage of fluid, causing a condition of blocking of the sprayer (OFF) (Figs. 9a and 9b) and a position rotated approximately through 90° with respect to the previous one wherein one of the furrows 52 is positioned at said vertical channel 27 allowing the passage of the fluid (ON) (Figs. 8a and 8b).

As mentioned, the spring 42 tends to push constantly the piston 41 against the nozzle 16. With the sprayer in ON position, when the pressure of the fluid in the outlet duct 29, acting on the plunger 44, overcomes the elastic force of the spring 42, the piston 41 moves backwards slightly, distancing its conical tip 45 from the nozzle 16, allowing in this way the delivery of the fluid.

The functioning of the sprayer with precompression system will now be described, taking account of what has already been said previously about the functioning of the sprayer in itself.

On the first actuation of the trigger lever 17, with the cam 50 of the piston 41 in open position, the plunger 21 pumps the air contained in the chamber 22 towards the vertical 27 and horizontal 28 channels of the outlet duct 29. After some actuations the pressure in the channels 27 and 28 increases and acting on the plunger 44 of the piston 41 causes a backward movement of the latter in contrast to the action of the precompression spring

42, thus freeing the delivery nozzle 16 through which the air exits. By continuing to actuate the trigger lever 17, liquid is primed from the container through the dipper tube 25 and pumped towards the outlet duct 29. The liquid which cannot be compressed will cause the backward movement of the piston 41, as mentioned previously, and at the same time the spring 42 will continue to exert constantly a force in the opposite direction, creating an additional pressure on the liquid in the horizontal channel 28, which will have a greater speed or acceleration in output from the nozzle 16.

It should be noted that the constant force exerted by the precompression spring 42 on the piston 41 also allows a rapid closure of the channel 28 supplied by the piston 41 which continues to push the liquid outwards.

The practical effect obtained with the system of precompression according to the invention is that in any way the trigger lever 17 is actuated, as a hypothesis also slowly and/or partially, in any case a nebulisation of the liquid is obtained at the outlet of the nozzle 16, as schematically shown in Fig. 5, thanks to the pressure exerted thereon by the precompression spring 42, which would not occur in a sprayer not provided with system of precompression.

In Figs. 1 and 5, 6, 7 the arrows indicate the passage of the fluid according to the position of the trigger lever 17.

In the embodiment illustrated, the outlet duct 29 has an L configuration, with the two channels 27 and 28 orthogonal one in relation to the other and the horizontal channel 28 parallel to the chamber of the pump 22. It is however clear that the two channels 27, 28 of the outlet duct 29 can be differently angled one in relation to the other, just as the chamber of the pump 22 could be tilted with respect to said channels 27, 28.

Naturally the invention is not limited to the particular embodiment previously described and illustrated in the accompanying drawings, but instead numerous detail changes can be made thereto, within the reach of the person skilled in the art, without thereby departing from the scope of the same invention as defined in the annexed claims.