Pump for dispensing a fluid product

Abstract

The invention relates to a pump comprising: a pump body (1) defining a slide shaft (11), an actuating rod (2) that is movable in the pump body (1), a plunger (3) mounted on the actuating rod (2), which slides sealingly in the slide shaft (11) over a plunger stroke, the plunger (3) forming a lower lip (31) and an upper lip (32), a collar (4) fixedly mounted in the pump body (1) and a return spring (5) that urges the plunger (3) against the collar (4) in the rest position, wherein the slide shaft (11) defines a main section (111) and a secondary section (112), the main section (111) having a smaller diameter than the secondary section (111), and wherein the lower lip (31) is constantly in contact with the main section (111) over the plunger stroke while the upper lip (32) is located at the height of the secondary section (112) in the rest position and is in contact with the main section (111) at least at the end of the stroke of the piston, the invention being characterised in that: the upper sealing lip (32) is in contact with the secondary section (112) in the rest position, and the plunger (3), in the rest position, is in sealed contact with the collar (4) only via its sealing upper lip (32).

Description

[0001] Fluid product dispensing pump

[0002] The present invention relates to a fluid product dispensing pump comprising a pump body internally defining a sliding barrel. The pump also comprises an actuating rod movable back and forth in the pump body and a piston mounted on the actuating rod and sliding in a sealed manner in the sliding barrel over a piston stroke. The piston forms a lower sealing lip and an upper sealing lip. The pump also comprises a ferrule fixedly mounted in the pump body and a return spring which biases the piston against the ferrule in the rest position of the pump. This is a conventional design for a manual pump in the fields of perfumery, cosmetics, pharmacy and food.

[0003] The sliding barrel is generally cylindrical over its entire height with a constant diameter, so that the two sealing lips are permanently subjected to a constant radial stress along the piston stroke, but also in the rest position, in which the piston abuts against the ferrule under the action of the return spring. This constant radial stress also implies significant constant friction, which therefore reduces the bearing force of the piston against the ferrule and therefore affects the quality of the seal between these two parts in the rest position. In addition, in the case where the ferrule is not perfectly centered in the sliding barrel, which is not uncommon, the piston is then deformed, which can lead to a sealing defect, either at the sliding barrel, or at the ferrule, or both. And since the pump is at rest, the fluid leakage can be significant.

[0004] The aim of the present invention is to guarantee perfect sealing of the pump in the rest position.

[0005] To do this, the present invention proposes that the sliding barrel defines a main distribution section and a secondary rest section, the main distribution section having a diameter smaller than that of the upper section, the lower sealing lip being constantly in contact with the main distribution section over (the entire) piston stroke, while the upper sealing lip is located axially at the height of the secondary rest section in the rest position and in contact with the main distribution section at least at the end of the piston stroke, and preferably over the major part of the piston stroke, characterized in that: the upper sealing lip is in contact with the secondary rest section in the rest position, and the piston, in the rest position, is in sealed contact with the ferrule only with its upper sealing lip.

[0006] Thus, the lower lip, always in contact with the main section of the barrel, already ensures a good seal and the upper lip, freed from its strong radial constraint with the barrel, can center itself freely on the ferrule, flare out and ensure a perfect seal, both with the ferrule and the secondary rest section. The seal with the ferrule is all the better as the friction of the piston in the barrel is reduced, which increases the thrust force of the return spring on the piston, which is thus pressed more strongly against the ferrule. In addition, the upper lip is preserved, which is less constrained against the barrel in the rest position, which still represents the major part of the life of the pump. The advantages are therefore multiple: release of the radial constraint on the upper lip, centering on the ferrule, flaring of the upper lip, reinforced sealing on the ferrule, contact of the upper lip with the barrel, extended service life.

[0007] The fact that the ferrule only comes into contact with the upper sealing lip means that the thrust force exerted by the return spring is concentrated and is applied to the tight pressed contact between the upper sealing lip and the ferrule, which causes the radial deformation (flaring) of the upper lip until it establishes contact with the secondary rest section in the rest position.

[0008] According to a practical embodiment, the ferrule may define a frustoconical contact surface and the upper sealing lip may comprise an upper end which internally defines a rounded contact surface, which comes into sealed pressed contact against the frustoconical contact surface in the rest position. This sealed pressed contact is advantageously the only one between the piston and the ferrule.

[0009] Furthermore, the upper sealing lip may include an upper end that externally defines a sealing sliding edge, which comes into sealing contact with the main dispensing section of the barrel.

[0010] According to one aspect of the invention, the main distribution section may be cylindrical and the secondary rest section may be frustoconical. Alternatively, the main distribution section and the secondary rest section may be cylindrical and connected by a frustoconical connecting section.

[0011] Generally, it is necessary to allow outside air into the bottle as fluid is extracted from it. This outside air passes through a venting passage which follows the ferrule. According to the invention, this venting passage can be closed in the rest position by the sealed contact between the upper sealing lip and the ferrule. Thus, any leakage of fluid through this venting passage is impossible.

[0012] The spirit of the invention lies in reducing the radial stress on the upper sealing lip to improve its centering, increasing its axial support against the ferrule to flare it so as to establish contact with the secondary rest section in the rest position.

[0013] The invention will now be described in more detail, with reference to the attached drawings, giving, as non-limiting examples, three embodiments of the invention.

[0014] In the figures:

[0015] Figure 1 is a vertical cross-sectional view through a pump of the invention, in the rest position,

[0016] Figure 2 is a greatly enlarged view showing a detail of the pump of Figure 1,

[0017] Figure 3 is a view similar to that of Figure 2 at the start of actuation, and Figure 4 is a view similar to Figures 2 and 3 in the middle of actuation.

[0018] Referring first to Figure 1, the general structure of the pump will be described. It comprises a pump body 1, an actuating rod 2, a piston 3, a ferrule 4, a return spring 5 and a ball 6 forming a movable inlet valve member.

[0019] The pump body 1 is generally cylindrical and of revolution. It internally defines a sliding barrel 11 for the piston 3. The pump body 1 forms at its lower end an inlet sleeve 12, which can receive a dip tube. In the extension of the inlet sleeve 12, there is an inlet valve seat 13, on which the ball 6 rests. The seat 13 and the ball 6 together form the inlet valve of the pump. In place of the ball 6, other shapes for a movable valve member can be imagined. At its upper end, the pump body forms a projecting collar 14, which can be grooved externally.

[0020] The actuating rod 2 is movable back and forth in the pump body 1. The rod 2 here results from the assembly of two parts, namely an upper part 20 and a lower part 25. The upper part 20 comprises a rod end 21 intended to receive a pusher, on which a user presses to move the actuating rod 2. Below this rod end, the rod 2 forms an external skirt 22 and an internal sleeve 24. The upper part 20 is axially traversed by a conduit 23. The lower part 25 forms a pin 26 which is fixedly engaged in the internal sleeve 24, as well as a seat 27 for the pump outlet valve.

[0021] The piston 3 comprises a lower sealing lip 31 and an upper sealing lip 32, which are located on the outside of the piston. The two lips 31 and 32 are oppositely oriented, but have the same external diameter. The piston 3 also forms an internal lip 34 of reduced diameter. The piston 3 also forms a valve lip 33, which extends concentrically inside the lower sealing lip 31.

[0022] The lower sealing lip 31 and the upper sealing lip 32 come into sealed sliding contact in the sliding barrel 11. The inner lip 34 comes into sealed sliding contact in the outer skirt 22. The valve lip 33 comes into selective sealed contact with the seat 27, so as to together constitute the outlet valve of the pump.

[0023] A pump chamber C is thus formed in the pump body 1 between the inlet valve 13, 6 and the outlet valve 27, 33. The piston 3 is mounted on the actuating rod 2, so as to be able to move between the seat 27 and the lower edge of the external skirt 22, with the internal lip 34 sliding in the external skirt 22. When the valve is opened under the effect of the pressure prevailing in the pump chamber C, the latter communicates with the conduit 23, so that the fluid product is discharged from the pump chamber C to the pusher through the conduit 23.

[0024] The ferrule 4 is fixedly mounted in the pump body 1, and more precisely around the upper part of the pump body 1, which forms the projecting collar 14. The ferrule 4 comprises an internal stop section 41 and an external snap-in section 42, which is in snap-in engagement around the collar 14. The ferrule 4, which is a kind of stop ring, could also be limited to the internal stop section 41.

[0025] The return spring 5 rests on a cage 7, which limits the degree of freedom of the ball 6, and under the actuating rod 2. The spring 5 pushes the actuating rod 2 upwards, driving with it the piston 3, which is pushed into abutment against the ferrule 4, and more precisely its internal stop section 41. The axial contact between the rod 2 and the piston 3 is made at the outlet valve 27, 33 and the axial contact between the piston 3 and the ferrule is made at the upper sealing lip 32. The ferrule 4 thus defines the rest position of the piston, of the actuating rod 2 and of the pump as a whole.

[0026] When a user presses the pusher (not shown) mounted on the rod end 21 of the actuating rod 2, the actuating rod descends and pushes into the pump body 1. The upper sealing lip 32 leaves its contact with the ferrule 4 and the valve lip 33 also leaves its contact with its seat 27. The pump chamber C is open towards the conduit 23 and the piston 3 will perform a complete stroke in the sliding barrel 11. The ball 6 is pressed against its seat 13. As soon as the user releases pressure on the pusher, the actuating rod is returned to its rest position under the action of the spring 5. The outlet valve closes and the inlet valve opens, to draw a new dose of fluid product into the pump chamber C. Outside air can enter the fluid product reservoir through a vent passage 4e, formed around of the internal stop section of the ferrule 4.

[0027] This is a very typical design and operation for a hand pump.

[0028] According to the invention, the sliding barrel 11 is not perfectly cylindrical over its entire height, but has at its upper end a portion of increased diameter. More precisely, in the embodiment illustrated in the figures, the sliding barrel 11 defines a main distribution section 111, which extends over the majority of the height of the barrel, and a secondary rest section 112, which extends over a reduced portion of the height of the barrel, at its upper end. In a variant not shown, the main distribution section 111 could be more reduced in height and the secondary rest section 112 could extend further. For example, the secondary rest section 112 could have the same height as the main distribution section 111, or even more.

[0029] The main distribution section 111 has a smaller diameter than that of the secondary rest section 112. The increase in diameter of the secondary rest section 112 relative to the main distribution section 111 is of the order of a few hundredths, or even tenths, of millimeters. The main distribution section 111 is cylindrical over its entire height, while the secondary rest section may be frustoconical. Preferably, as shown in the figures, the secondary rest section 112 is cylindrical and is connected to the main distribution section 111 by a frustoconical connecting section 113.

[0030] When the piston 3 is in the rest position, as can be seen in Figure 2, the upper sealing lip 32 is pressed against the ferrule 4, which deforms it so as to come into contact with the secondary rest section 112. The ferrule 4 flares the upper sealing lip 32, so that its diameter increases until it comes into contact with the secondary rest section 112. When the piston 3 is moved downwards, the upper sealing lip 32 leaves its pressed contact with the ferrule 4 and returns to its unstressed shape, i.e. with a reduced rest diameter. Therefore, the upper sealing lip 32 also leaves its contact with the secondary rest section 112. Then, the upper sealing lip 32 engages on the frustoconical connecting section 113, as seen in Figure 3. It can be noted that the upper sealing lip 32 is not in contact with the frustoconical connecting section 113.Continuing its stroke, as seen in Figure 4, the upper sealing lip 32 comes into contact with the main distribution section 111, where the piston 3 will travel most of its stroke. And even with a lower main distribution section 111 as mentioned above, the upper sealing lip 32 will still come into contact with the main distribution section 111 at least at the end of the piston stroke.

[0031] In more detail, the lower end of the outer skirt 41 of the ferrule 4 defines a downwardly and outwardly facing frustoconical contact surface 412. On the other hand, the upper sealing lip 32 comprises an upper end which internally defines a rounded contact surface 322, which comes into sealing pressed contact against the frustoconical contact surface 412 in the rest position. Thus, the rounded contact surface 322 can slide on the frustoconical contact surface 412 and flare out until it comes into contact with the secondary rest section 112. The upper sealing lip 32 is therefore constrained in the rest position, so as to establish a double seal, which is extremely beneficial.

[0032] Without departing from the scope of the invention, conversely, the ferrule 4 could define a rounded contact surface and the upper sealing lip 32 could define a frustoconical contact surface. In all cases, the “rounded against frustoconical” contact or vice versa is advantageous, it allows relative sliding until reaching the final maximum sealing position. Advantageously, the upper end of the upper sealing lip 32 externally defines a sealed sliding edge 321, which comes into contact with the secondary rest section 112.

[0033] It should be noted that the piston 3, in the rest position, only comes into sealed contact with the ferrule 4 with its upper sealing lip 32. In other words, the rounded contact surface 322 is the only contact area of ​​the piston 3 with the ferrule 4. And due to the taper of the truncated contact surface 412 and the rounding of the rounded contact surface 322, the centering of the piston 3 relative to the ferrule 4 is ensured. In addition, the axial contact is increased, because the radial stress is reduced or canceled. It can be noted that the vent passage 4e is closed in the rest position by the sealed contact between the upper sealing lip 32 and the ferrule 4.Thus, the sealing of the pump is entirely ensured, on the one hand by the lower sealing lip 31, which remains permanently in sealed sliding contact with the main distribution section 111 of the barrel 11, and on the other hand by the upper sealing lip 32, which is in reinforced sealed contact with the ferrule 4.

[0034] Thanks to the invention, we have a pump whose sealing is reinforced in the rest position.

Claims

Claims 1. Fluid product distribution pump comprising: - a pump body (1) internally defining a sliding barrel (11), - an actuating rod (2) movable back and forth in the pump body (1), - a piston (3) mounted on the actuating rod (2) and sliding tightly in the sliding barrel (11) over a piston stroke, the piston (3) forming a lower sealing lip (31) and an upper sealing lip (32), - a ferrule (4) fixedly mounted in the pump body (1), - a return spring (5) which urges the piston (3) against the ferrule (4) in the rest position of the pump, in which the sliding barrel (11) defines a main distribution section (111) and a secondary rest section (112), the main distribution section (111) having a diameter smaller than that of the secondary rest section (112), the lower sealing lip (31) being constantly in contact with the main distribution section (111) on the piston stroke, while the upper sealing lip (32) is located axially at the height of the secondary rest section (112) in the rest position and in contact with the main distribution section (111) at least at the end of the piston stroke, characterized in that: - the upper sealing lip (32) is in contact with the secondary rest section (112) in the rest position, and - the piston (3), in the rest position, is in sealed contact with the ferrule (4) only with its upper sealing lip (32).

2. Pump according to claim 1, in which the ferrule (4) defines a frustoconical contact surface (412) and the upper sealing lip (32) includes an upper end that internally defines a rounded contact surface (322), which slides and comes into sealing pressed contact against the frustoconical contact surface (412) in the rest position.

3. Pump according to claim 1 or 2, in which the upper sealing lip (32) is deformed outwards by the ferrule, so as to flare and come into contact with the secondary rest section (112) in the rest position.

4. Pump according to claim 1, 2 or 3, in which the upper sealing lip (32) comprises an upper end which externally defines a sealed sliding edge (321), which comes into sealed contact with the main distribution section (111).

5. Pump according to any one of the preceding claims, in which the main distribution section (111) is cylindrical and the secondary rest section is frustoconical.

6. Pump according to any one of the preceding claims, in which the main distribution section (111) and the secondary rest section (112) are cylindrical and connected by a frustoconical connecting section (113).

7. Pump according to any one of the preceding claims, defining a vent passage (4e), which is closed in the rest position by the sealed contact between the upper sealing lip (32) and the ferrule (4).

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