Precompression Pump Formed Within the Pusher Element

The present invention concerns a device for dispensing a product held in a container, and more specifically a precompression pump.

The present pumps generally comprise a pump body having a pump chamber, an inlet valve, an outlet valve, a piston sliding in said pump body and an actuating shaft in order to activate the pump by means of a pusher. A return spring acting on the actuating shaft and/or on the pusher, returns the pump to its rest position after each actuation.

The present precompression pumps generally comprise in addition a differential piston forming an outlet valve and sliding in the pump body or on the actuating shaft, under the effect of a precompression spring.

Such a known precompression pump is revealed in document FR-2 346 056.

These known precompression pumps, even though they operate correctly, present a certain number of drawbacks. In fact, they contain numerous parts and are therefore difficult to manufacture and complicated to assemble. Furthermore, their dimensions, in particular their height, are quite considerable, which can represent a disadvantage from the point of view of adaptability on small containers, from the point of view of stocking or from an esthetic viewpoint. Besides, they do not comprise simple means and which do not involve increased manufacturing cost, which permit adjustment of the volume of the product dose discharged each time the pump is actuated.

The objective of the present invention is to provide an improved precompression pump, which does not present the above mentioned drawbacks.

The objective of the present invention is to embody a new precompression pump formed by fewer parts than the present pumps, and consequently less expensive to manufacture and simpler to assemble. Specifically, the objective of the present invention is to provide such a pump comprising only one single spring and not comprising an actuating shaft.

The present invention also aims to provide a new precompression pump the height of which is reduced. Specifically, the objective of the invention is to supply such a pump in which the dead volume is minimized.

Another objective of the invention is to provide such an improved precompression pump where the volume of the dose discharged with each actuation can be modified by the user, without increasing the manufacturing costs.

Consequently, the objective of the invention is a precompression pump to dispense selectively a product held in a container, said pump comprising a pump chamber having an inlet valve, a piston sliding in a first cylinder, a differential piston forming an outlet valve of said pump chamber and sliding in a second cylinder between a closing position and an opening position of the pump chamber, said pump comprising in addition a pusher having a dispensing hole, said pusher element being movable between a rest position and a pump actuating position, characterized in that the said first and second cylinders are directly formed by the first and second inner walls respectively, of said pusher, said pusher thus delimiting said pump chamber in part, and in that said pump only comprises one single spring resting on the one hand on a portion of the pusher and on the other on a portion of the differential piston, said spring acting on the one hand as return spring of the pusher toward its rest position, and on the other as precompression spring for the differential piston.

Thus, the pump according to the invention offers the advantage of eliminating in particular the actuating shaft and one of the two return and precompression springs. The height of the pump and the dead volume are therefore considerably reduced, the pump chamber and the single spring being located inside the pusher, and the number of component parts of the pump is reduced, so that its manufacturing and assembly are more economical, both from a point of view of time and from the point of view of cost.

Said piston is preferably fixed with regard to the container.

Advantageously, said pump comprises a fixed part intended to be attached to the neck of the container, said fixed part delimiting the pump chamber in part and incorporating said piston, said pusher sliding tightly on said fixed part.

In particular, said fixed part also forms the seat of said inlet valve of the pump chamber, said fixed piston being formed by a ring-shaped lip of said fixed part sliding tightly in said first cylinder of said pusher.

Advantageously, said fixed part comprises additionally means to affix the pump to the neck of the container. Thus, the use of a detachable attachment ring is eliminated, which still reduces the number of component parts of the pump even further.

Advantageously, said means of affixing the pump to the neck of the container are small snap-on hooks intended to snap onto said neck of the container and work together after they snap-on with a collar which is intended to be mounted around said hooks in order to keep said fixed part tightly on the neck.

Preferably, said collar, after its mounting onto the fixed part, works together at its upper end with the pusher in order to form a stop defining the rest position of said pusher.

Advantageously, said collar, after its mounting on said fixed part, is movable with regard to the latter between two limit positions in order to define at least two different pump chamber volumes. The user can thus regulate at will the volume of the product dose which will be discharged with each actuation.

Specifically, the mounting and/or the shifting of said collar on said fixed part is done by screwing.

Other features and advantages of the invention will appear in the course of the following detailed description, given by way of non exhaustive examples with regard to the attached drawings, where

FIG. 1 is a schematic cross-section view of a precompression pump according to the invention, in its rest position, and

FIGS. 2 and 3 are schematic views similar to FIG. 1, representing a variant of the invention incorporating a collar permitting adjustment of the volume of the product dose discharged.

With reference to the Figures, the precompression pump according to the invention comprises a piston 1 which slides in a first cylinder 2 formed directly in pusher 6. Likewise, the pump comprises a differential piston 5, assuring the precompression and sliding in a second cylinder 11 also formed directly in pusher 6. Pump chamber 3 is therefore partially located inside pusher 6.

Piston 1 is preferably fixed and advantageously forms an integral part of a fixed part 20 which is being attached to the neck of the container (not illustrated), for example by means of snap-in hooks 22 and a collar 21, which is being mounted around said hooks 22. This fixed part 20 therefore necessarily forms part of a portion of the pump body by delimiting pump chamber 3 in part, and by receiving for example a ball bearing 4 to form its inlet valve. On the other hand, fixed part 20 forms, by means of a ring-shaped lip, piston 1. Besides, it also acts advantageously as attachment ring.

According to the invention, said ring-shaped lip forming piston I slides tightly in said first cylinder 2 formed directly by an inner wall of pusher 6. Likewise, differential piston 5 slides in said second cylinder 11 formed directly by an inner wall of pusher 6, between a closing position, where it seals passage 8 between pump chamber 3 and dispensing hole 7, e.g. a nozzle, and an opening position, where it opens said passage 8. One single spring 15, which is supported on the one hand on an inner wall of pusher 6, and on the other hand on said differential piston 5, acts upon pusher 6 toward its rest position and differential piston 5 toward it closing position. Said spring 15 thus acts at the same time as return spring and as precompression spring for the pump according to the invention. Thus, when the user presses down on pusher 6, the latter slides on said fixed part 20 at the level of piston 1. The product contained in dispensing chamber 3 being incompressible, a surge pressure is produced in said chamber 3, which urges said differential piston 5, against the thrust of said spring 15, toward the opening position. As passage 8 is released, the product contained in chamber 3 is discharged via nozzle 7. Then pusher 6 is released and spring 15 returns it toward its rest position, as well as differential piston 5 toward its closing position. Simultaneously, the inlet valve 4 is opened by the vacuum forming in pump chamber 3 and the latter is again filled with product from the container (not illustrated), a vent hole 25 being provided to this effect.

The pump according to the invention thus presents the advantage of operating in the same manner as a classical pump, while incorporating fewer component parts. Furthermore, due to the absence of an actuating shaft, the height of the pump is considerably reduced. On the other hand, single spring 15 of the pump located in the pusher minimizes the dead volume in the pump.

Collar 21, once mounted on fixed part 20 to keep it tightly affixed to the container neck, works together advantageously with pusher 6 in order to form a stop determining the rest position of said pusher.

Advantageously, as represented in FIGS. 2 and 3, collar 21 can be shifted with regard to fixed part 20, after having been mounted onto it. Thus, the rest position of the piston and therefore the volume of pump chamber 3 can be modified or adjusted by the user. Specifically, collar 21 can be shifted by screwing between two limit positions represented by FIGS. 2 and 3, but any other known means of shifting the position of collar 21 with regard to fixed part 20 is conceivable (e.g. axial displacement).