Pump

Abstract

The invention relates to a pump comprising a fluid product chamber (Cp), an actuating rod (T) and a return means (Cd) for returning the actuating rod (T) to an idle position, wherein the actuating rod (T) is provided with a push member (P) that can be actuated by a user, characterised in that the return means comprises a depression chamber (Cd) having a volume that can be varied between a minimum volume state and a maximum volume state by moving the actuating rod (T), the minimum volume state being obtained when the actuating rod (T) is in the idle position and the maximum volume state being obtained when the actuating rod (T) is in the depressed position, wherein the maximum volume state corresponds to a maximum depression and the minimum volume state corresponds to a minimum depression and the actuating rod (T) is biased towards its idle position by the depression prevailing in the depression chamber (Cd).

Description

[0001]Pump The present invention relates to a pump comprising a fluid chamber of variable volume, as well as an actuating rod axially movable between a rest position and a depressed position, so as to vary the volume of the chamber respectively between a maximum volume state and a minimum volume state. The pump comprises a return means for returning the actuating rod to the rest position, corresponding to the maximum volume state of the fluid chamber. The actuating rod is provided with a pusher actuable by a user. The preferred fields of application of the invention are those of pharmacy, cosmetics and perfumery, without excluding others. Conventionally, the return means is in the form of a spring which is generally made of metal.The problem with these metal springs is that they prevent or complicate the recycling of the pump, especially since they are arranged in the pump body. There are also plastic springs, which are more easily recycled, but they tend to lose their stiffness over time. The present invention seeks to overcome the disadvantages of these prior art springs by proposing another type of elastic return means, which does not present any recycling or stiffness problems.To do this, the present invention proposes that the return means comprises a vacuum chamber, the volume of which varies between a minimum volume state and a maximum volume state by movement of the actuating rod, the minimum volume state of the vacuum chamber being reached in the rest position of the actuating rod and the maximum volume state of the vacuum chamber being reached in the depressed position of the actuating rod, the maximum volume state of the vacuum chamber corresponding to a maximum vacuum and the minimum volume state of the vacuum chamber corresponding to a minimum vacuum, the actuating rod being urged towards its rest position by the vacuum prevailing in the vacuum chamber. The vacuum chamber thus generates a vacuum from a point where the pressure of the vacuum chamber is close to or equal to atmospheric pressure.The pressure in the vacuum chamber is therefore always less than or equal to atmospheric pressure. The vacuum increases as the actuating rod is moved from its rest position to its depressed position. It is a sort of reverse air pump. According to the invention, the pump further comprises mechanical means, independent of the vacuum in the vacuum chamber, actuable by the user to return and maintain the vacuum chamber in its minimum volume state. Thus, starting from the maximum volume state (maximum vacuum), the vacuum chamber will decrease in volume, as soon as the user releases pressure on the pusher. This decrease in volume under the action of the vacuum continues until the mechanical means are engaged.The user can then actuate these mechanical means to further reduce the volume of the vacuum chamber to finally reach its minimum volume state. The vacuum in the minimum volume state does not need to be present during the entire actuation sequence of the mechanical means. It is sufficient for the vacuum to engage the mechanical means. Advantageously, the mechanical means are controlled by the pusher via the actuating rod. In other words, the user grasps the pusher and moves it, which has the effect of actuating the mechanical means. The movement of the pusher can be rotary, axial or both at the same time. According to the invention, the mechanical means comprise a threaded socket, which allows the pusher and the actuating rod to be moved both axially and rotationally.Advantageously, the threaded grip can define an axial stroke, which is delimited on one side by a high stop corresponding to the minimum volume state of the vacuum chamber and on the other side by a threaded grip release allowing a subsequent variation of the volume of the vacuum chamber towards its maximum volume state. From an ergonomic and gestural point of view, the user will grasp the pusher to turn it through a determined angle, for example a quarter turn or a half turn, to bring it selectively into the locked or unlocked position. This locking / unlocking system by rotation of the pusher is conventional. In the context of the invention, the actuation of the locking / unlocking system also and simultaneously causes the actuation of the mechanical means, and this, without the user even perceiving it. Thanks to the mechanical means, the vacuum chamber always returns to the same starting point of minimum volume.According to another interesting feature of the invention, which is advantageously combinable with mechanical means, the vacuum chamber communicates with the outside in its state of minimum volume. Thus, even if the vacuum chamber leaks and lets air in, this air will be evacuated to the outside, so that the vacuum chamber always leaves the same pressure, which is close to atmospheric pressure. This initial or final leak can be implemented independently of the mechanical means, but it is then necessary that the vacuum in the vacuum chamber is sufficient to return the vacuum chamber to or close to its state of minimum volume. This is possible, but difficult to achieve in practice and especially in a repeatable manner. This is why this initial or final leak finds a particular advantage in combination with the mechanical means, which guarantee that the vacuum chamber always returns to its state of minimum volume.It can then be said that the mechanical means supplement or complement the vacuum to ensure that the vacuum chamber is reset at each actuation cycle by connecting it to the outside. According to one embodiment of the invention, the actuation rod comprises a vacuum chamber piston which slides axially in a sealed manner in a vacuum chamber barrel, so as to define the vacuum chamber between them, the actuation rod forming a vent groove, which connects the vacuum chamber to the outside in the rest state of the actuation rod, which corresponds to the state of minimum volume of the vacuum chamber.The groove, groove or passage establishes air communication between the vacuum chamber and the outside when the pump is at rest, this communication being cut off so as to isolate the vacuum chamber, as soon as the actuating rod leaves its rest state or shortly after leaving its rest state. A stroke of a few tenths of a millimeter is sufficient to isolate the vacuum chamber. According to another aspect of the invention, the actuating rod may comprise a piston member and a valve, the piston member forming the vacuum chamber piston sliding in the vacuum chamber barrel, the piston member also forming a fluid product chamber piston sliding in a fluid product chamber barrel, the piston member advantageously forming a movable outlet valve member for the fluid product chamber and the valve advantageously forming an outlet valve seat for the fluid product chamber.Advantageously, the piston member is axially movable relative to the valve under the effect of the pressure prevailing in the fluid chamber, but is rotated by the valve. Advantageously, the threaded connection is located between the piston member and the vacuum chamber barrel. The piston member can be described as a differential piston, in that it moves under the effect of the pressure prevailing in the fluid chamber. Instead of this piston member, an actuating rod may be provided provided with a fixed vacuum chamber piston and a fluid chamber piston which slides on the actuating rod under the effect of the pressure prevailing in the fluid chamber.According to another approach to the invention, it can be said that the vacuum chamber defines a maximum axial stroke between its minimum volume state and its maximum volume state, this maximum axial stroke being broken down into: - a major stroke from the maximum volume state, which is induced by the vacuum prevailing in the vacuum chamber, and - a minor stroke up to the maximum volume state, which is induced by a rotational and / or axial drive of the pusher, which ends with an axial locking position of the pusher. The user, who takes hold of a dispenser on which the pump of the invention is mounted, will quickly understand that the pusher is in the locked position by pressing on it or by noting an instruction visible on the pusher. He will therefore drive the pusher in rotation over a determined angle to unlock it.In doing so, but imperceptibly, he actuated the mechanical means, which brought the vacuum chamber from its state of minimal volume in which it communicates with the outside into an intermediate state in which it is isolated from the outside. In the case where the mechanical means implement a threaded socket, the intermediate position corresponds to the end of the threaded socket, in which the actuating rod is released from this threaded socket. The user then presses axially on the pusher, which has the simultaneous effects of dispensing fluid product and generating an increasing vacuum in the vacuum chamber. Once the dispensing of fluid product is complete, the user releases his axial pressure on the pusher, so that the vacuum in the vacuum chamber has the effect of returning the actuating rod and its pusher to the rest position.However, the return stroke of the rod is stopped in the intermediate position, which corresponds to the engagement of the mechanical means. In the case where the mechanical means implement a threaded engagement, the vacuum rises the actuating rod until the threads engage. From then on, the user only has to turn the pusher to lock it, which simultaneously has the effect of returning the actuating rod to the rest position and the vacuum chamber to its state of minimum volume in which it communicates with the outside through the venting groove of the actuating rod. The locked position corresponds to a stop of the threaded engagement. The spirit of the invention lies in the threaded engagement which allows the air spring to return to its starting point. Furthermore, in order to overcome a risk of leakage, it is ventilated at its starting point.The threaded plug combined with the leak at the starting point provides a synergistic effect, making its operation perfectly repeatable, and therefore reliable. The air spring is thus reset after each actuation. The invention will now be more fully described with reference to the accompanying drawings, giving by way of non-limiting example, an embodiment of the invention.In the figures: Figure 1 is a vertical cross-sectional view through a fluid dispenser incorporating a pump according to the invention at rest locked, Figure 2a is an enlarged view of Figure 1 with the pump at rest locked, Figure 2b is a view similar to Figure 2a with the pump unlocked, Figure 3a is a greatly enlarged view of a part of Figure 2a, Figure 3b is a greatly enlarged view of a part of Figure 2b, Figures 4a, 4b and 4c represent the valve of the pump according to the invention, Figures 5a, 5b, 5c and 5d represent the piston member of the pump according to the invention, and Figures 6a, 6b, 6c and 6d represent the body of the pump according to the invention Figure 1 shows the pump of the invention mounted on a fluid reservoir R, which is not critical to the present invention. In fact, this tank R can be of any nature, of any shape, and made of any suitable material.It is sufficient that it forms an opening, for example in the form of a neck, on which the pump of the invention can be mounted in a fixed and sealed manner. The pump of the invention firstly comprises a pump body 3 which receives fixed elements 4, 5 and 6 as well as a movable element, namely an actuating rod T. The pump body 3 forms a ring 35 intended to cooperate with the neck of the reservoir R for fixing the pump to the reservoir. Below this fixing ring 35, the pump body 3 forms an assembly sleeve 36, in which are fixedly mounted a base part 6 provided with a dip tube 61, a barrel part 5 provided with an inlet valve 51 and a sleeve 4 which serves for the sealed guidance of the actuating rod T. The barrel part 5 is held between the base part 6 and the sleeve 4. The base part 6 can be permanently snapped into openings formed by the sleeve 36 of the pump body 3.The design of these fixed parts 4, 5 and 6 is not critical for the present invention, so that other architectures can be envisaged without departing from the scope of the invention. The actuating rod T is slidably mounted inside the pump body 3 along a longitudinal axis X. A part of the actuating rod T emerges from the pump body 3 upwards: this emerging part receives a pusher P, on which the user can press to axially move the actuating rod T back and forth inside the pump body 3. In Figure 1, the pusher P is a nasal type pusher, but any pusher can be mounted on the actuating rod T. The pusher P is not critical for the present invention. The actuating rod T is here of a particular type, since it comprises a valve 1 in the upper part and a piston member 2 in the lower part.These two parts are connected to each other with freedom of axial movement along the X axis. However, they are fixedly connected to each other in rotation so that the rotation of the valve 1 causes the rotation of the piston member 2. And since the tappet P is fixedly mounted on the valve 1, the rotation of the tappet P causes the rotation of the actuating rod T as a whole. More precisely, the valve 1 comprises a tube 11 which extends upwards from a base 13. The valve 1 is more visible in figures 4a, 4b and 4c. The tube 11 forms a free end on which the tappet P is fixedly mounted both axially and in rotation. It can be noted that the tube 11 forms a vent groove 12, the largest dimension of which is axial. This vent groove 12 is located near the base 13. Its function will be given below. The base 13 has an increased diameter compared to that of the tube 11.The base 13 firstly comprises two longitudinal axial ribs 14 which project radially outwards. The two ribs 14 are arranged diametrically opposite each other. It can even be noted that the vent groove 12 is located axially just above one of the ribs 14. Below the ribs 14, the base 13 forms an annular groove 15, which is used to receive an O-ring G15, visible in Figure 1. Internally, the base 13 forms a housing 16 for another O-ring G16, also visible in Figure 1. The valve 1 is internally crossed by a through conduit 10 which extends from the housing 16 to the free upper end of the tube 11 on which the pusher P is mounted. The piston member 2 comprises a head 21 and a tube 25. The piston member 2 is more visible in Figures 5a, 5b, 5c and 5d. The head 21 externally forms a helical groove 22, the function of which will be given below.Below this helical groove 22, the head 21 forms a groove 23 for receiving an O-ring G23, visible in Figure 1. Internally, the head 21 defines a receiving housing 20, which forms two longitudinal axial recesses 24, intended for receiving the two ribs 14 of the valve 1, so as to block the two parts in rotation relative to each other. The recesses 24 have dimensions very slightly greater than those of the ribs 14 so as to be able to receive them without play or excessive friction, so that the two parts can still move axially by sliding. The tubing 25, at its lower end, forms with an internal housing 27 for an O-ring G27. At its upper end, the tubing 25 internally forms a movable valve member 26, which will cooperate with the O-ring G16 of the valve 1, so as to together form an outlet valve of the pump.As can be seen in Figure 5d, the receiving housing 20 communicates with the interior of the tubing 25 by passages formed around the movable valve member 26, which is connected to the tubing 25 by bridges of material. The pump body 3 is more visible in Figures 6a, 6b and 6d. The pump body 3 internally defines a sliding barrel 31, which has the particularity of forming at its upper end a helical thread 32. Above this helical thread 32, the pump body forms an axial stop 33 internally defining a housing 34 for an O-ring G34, visible in FIG. 1. Below the sliding barrel 31, the body 3 forms the fixing ring 35, already described, as well as the assembly sleeve 36. We will now refer again to FIG. 1, as well as to FIGS. 2a and 3a to explain the cooperation of these different parts within the pump of the invention.As already mentioned, the base 13 of the valve 1 is axially engaged inside the receiving housing 20 of the piston member 2, with the ribs 14 slidably engaged inside the recesses 24 of the receiving housing 20. The maximum engagement of the base 13 inside the receiving housing 20 results in a sealed contact between the O-ring G23 and the wall of the receiving housing 20, as well as a sealed contact between the O-ring G16 and the movable valve member 26. A slight axial displacement of these two parts from this maximum engagement position results in the seal G16 being detached from the movable valve member 26, while the O-ring G23 remains in sealed contact with the inner wall of the receiving housing 20. In other words, the neck seal G16 detaches, while the O-ring G23 slides in a sealed manner. Thus, a seal is always maintained between these two parts.This actuating rod T, constituted by the assembly of the valve 1 with the piston member 2, is integrated into the pump body 3 in the following manner. In the locked rest state of the pump, the head 21 of the piston member 2 is in threaded engagement with the barrel 31. More precisely, the helical thread 32 of the body 3 is in engagement with the helical groove 22 of the head 21 of the piston member 2. In this locked rest state, it can be noted that the head 21 is in contact with the stop 33. However, the O-ring G23 always remains in sealed sliding contact inside the barrel 31. The tubing 25 of the piston member 2 is engaged inside the sleeve 4 and slides in a sealed manner thanks to the O-ring G4. On the other hand, the tubing 25 is also engaged around the barrel 52 of the barrel part 5 with a sliding sealed contact ensured by the O-ring G27.Thus, a fluid product chamber Cp is created between the inlet valve 51 and the outlet valve formed by the O-ring G16 and the movable valve member 26. It can be said that the piston of the fluid product chamber Cp is formed by the O-ring G27 supported by the tubing 25. The valve 1, the base 13 of which is engaged in the head 21 of the piston member 2, projects with its tube 11 through the stop 33. It can be noted that the base 13 can also come into contact with the stop 33. The O-ring G34 surrounds the tube 11: however, in this locked rest position, it can be noted in Figure 3a that the sealed contact between the O-ring G34 and the tube 11 is broken by the vent groove 12, which is located axially at the level of the O-ring G34.From this locked rest position, shown in Figures 1, 2a and 3a, the user can grasp the pusher P and rotate it, which has the effect of rotating the piston member 2 inside the pump body 1 via the valve 1. Indeed, the torque applied to the pusher P is transmitted by the valve 1 to the piston member 2, due to the rotational blocking achieved by the engagement of the ribs 14 in the recesses 24. This rotation applied to the pusher P causes an actuation of the threaded engagement created between the helical groove 22 and the helical thread 32. As a result, the pusher P and the actuating rod T move axially downwards. This is shown in Figures 2b and 3b.The helical thread 32 is completely disengaged from the helical groove 22 and the head 21 with its O-ring G23 can then slide axially in a sealed manner in the barrel 31 of the pump body 3 by axial support on the pusher P. The space thus formed between the head 21 and the stop 33 constitutes a vacuum chamber Cd, which is created with the rotation of the pusher P and which increases even more by axial support on the pusher P. Thanks to the O-rings G23 and G34, the vacuum chamber Cd is isolated from the outside, so that an increasing vacuum occurs, as the head 21 moves away from the stop 33. Simultaneously, the O-ring G27 slides along the barrel 52, thus reducing the volume of the pump chamber Cp and increasing the pressure on the fluid product.In response to this increase in pressure, a slight axial displacement is created between the piston member 2 and the valve 1, so as to detach the O-ring G16 from the movable valve member 26, thus creating an outlet passage for the fluid product through the valve 1 and the pusher P. The operation of this differential piston will not be further described here, since it is known from the prior art. Once the pusher P is fully depressed, the dispensing of fluid product is complete and the user then releases the pressure exerted on the pusher P. The vacuum created inside the vacuum chamber Cd has the effect of returning the valve stem T to the rest position. In other words, the vacuum created in the vacuum chamber Cd urges the head 21 of the piston member 2 towards the stop 33.The O-ring G23 therefore moves in a sliding and sealed manner inside the barrel 31 until the head 21 comes into abutment on the start of the helical thread 32. The user then knows that it is necessary to lock the pump again by rotating the pusher, which has the effect of nesting the helical thread 32 in the helical groove 22. The end of the rotation, corresponding to the locked rest position, is reached when the head 21 comes into contact again against the stop 33. We then find ourselves in the configuration shown in Figures 1, 2a and 3a, in which the vacuum chamber Cd, reduced to a state of minimal volume, can communicate with the outside thanks to the lack of sealing generated by the venting groove 12. Thus, the stroke of the actuating rod P makes it possible to vary the volume of the vacuum chamber Cd between a state of minimal volume, or even zero, and a state of maximum volume.The stroke of the head 21, which can be likened to a vacuum chamber piston, with its O-ring G23 acting as a piston lip, can be broken down into two parts, namely a major stroke corresponding to the sealed sliding without a rotary component and a minor stroke corresponding to the threaded engagement of the thread 32 in the groove 22. The major stroke is generated by the vacuum prevailing in the vacuum chamber Cd, while the minor stroke is generated by the manual rotational drive of the pusher P. In other words, the major stroke is solely pneumatic, while the minor stroke is essentially mechanical. The threaded engagement between the thread 32 and the groove 22 can thus be described as mechanical means as opposed to the pneumatic means of the major stroke.The mechanical means, formed by the thread 32 and the groove 22, make it possible to return the actuating rod T securely to the locked rest position, in which the vacuum chamber Cd, reduced to its minimum volume state, communicates with the outside via the vent groove 12. It is easily understood by referring to Figure 3a, that this communication with the outside is very quickly broken as soon as the vent groove 12 is no longer located axially at the level of the O-ring G34. A stroke of a few tenths of a millimeter is enough to break this communication and to isolate the vacuum chamber Cd from the outside. The venting of the vacuum chamber Cd makes it possible to reset the pressure each time the pump is actuated.Thus, even in the case where the vacuum chamber Cd were leaking, and thus allowed air to enter inside, this air would be evacuated at the end of actuation, thanks to the venting of the chamber Cd through the venting groove 12. In the absence of mechanical means, constituted by the thread 32 and the groove 22, the operation of the pump is possible, but in this case it would be necessary for the vacuum inside the vacuum chamber Cd to be sufficient to bring the head 21 back into contact with the stop 33, so as to reestablish communication with the outside through the groove 12. Conversely, the pump can operate without a venting groove 12, but in this case it is necessary that there is no leakage at the level of the vacuum chamber Cd. Of course, the cumulative implementation of the mechanical means and the venting is particularly advantageous and constitutes the preferred embodiment.The pump described here incorporates a piston member 2 which can be described as a differential piston, since it moves not only by pressing on the pusher but also in response to a threshold pressure inside the fluid chamber Cp. Without departing from the scope of the invention, it is possible to implement the vacuum chamber Cd of the invention in a more conventional pump, in which the piston of the vacuum chamber is fixedly mounted on the actuating rod, while the piston of the fluid chamber Cp is slidably mounted on the actuating rod. Without departing from the scope of the invention, several vent grooves 12 and one or more than two ribs 14 can be provided. The O-rings implemented on different parts can be replaced by one-piece lips.Thanks to the invention, the metal or plastic spring of the prior art can be replaced by a pneumatic spring, part of the stroke of which results from the actuation of the pusher, which is preferably rotary. However, it is also possible to envisage moving the pusher only in the axial direction. As for the venting of the vacuum chamber Cd, it allows a reset to zero at each actuation.

Claims

Claims 1. Pump comprising a fluid chamber (Cp) of variable volume, as well as an actuating rod (T) axially movable between a rest position and a depressed position, so as to vary the volume of the fluid chamber (Cp), respectively between a maximum volume state and a minimum volume state, the pump comprising a return means (Cd) for returning the actuating rod (T) to the rest position, corresponding to the maximum volume state for the fluid chamber (Cp), the actuating rod (T) being provided with a pusher (P) actuable by a user, in which the return means comprises a vacuum chamber (Cd) of variable volume between a minimum volume state and a maximum volume state by moving the actuating rod (T),the minimum volume state of the vacuum chamber (Cd) being reached in the rest position of the actuating rod (T) and the maximum volume state of the vacuum chamber (Cd) being reached in the depressed position of the actuating rod (T), the maximum volume state of the vacuum chamber (Cd) corresponding to a maximum vacuum and the minimum volume state of the vacuum chamber (Cd) corresponding to a minimum vacuum, the actuating rod (T) being urged towards its rest position by the vacuum prevailing in the vacuum chamber (Cd), in which mechanical means (22, 32), independent of the vacuum in the vacuum chamber (Cd), are operable by the user to return and maintain the vacuum chamber (Cd) in its minimum volume state, characterized in that the mechanical means comprise a threaded socket (22, 32),which allows the actuating rod (T) and its pusher (P) to be moved both axially and in rotation., 2. Pump according to claim 1, wherein the mechanical means (22, 32) are controlled by the pusher (P) via the actuating rod (T).

3. Pump according to claim 1 or 2, wherein the threaded socket (22, 32) defines an axial stroke, which is delimited on one side by a high stop (33) corresponding to the minimum volume state of the vacuum chamber (Cd) and on the other side by a threaded socket release allowing a subsequent variation of the volume of the vacuum chamber (Cd) towards its maximum volume state.

4. Pump according to any one of the preceding claims, wherein the vacuum chamber (Cd) communicates with the outside in its minimum volume state. 5.Pump according to any one of the preceding claims, in which the actuating rod (T) comprises a vacuum chamber piston (G23) which slides axially in a sealed manner in a vacuum chamber barrel (31), so as to define between them the vacuum chamber (Cd), the actuating rod (T) forming a vent groove (12), which communicates the vacuum chamber (Cd) with the outside in the rest state of the actuating rod (T).

6. Pump according to any one of the preceding claims, in which the actuating rod (T) comprises a valve (1) and a piston member (2), the piston member (2) forming the vacuum chamber piston (G23) sliding in the vacuum chamber barrel (31), the piston member (2) also forming a fluid product chamber piston (G27) sliding in a fluid product chamber barrel (4), the piston member (2) advantageously forming. a movable outlet valve member (26) for the fluid chamber (Cp) and the valve 1() advantageously forming an outlet valve seat (G16) for the fluid chamber (Cp).

7. Pump according to claim 6, in which the piston member (2) is axially movable relative to the valve (1) under the effect of the pressure prevailing in the fluid chamber (Cp), but is rotated by the valve (1).

8. Pump according to claim 6 or 7, in which the threaded socket (22, 32) is located between the piston member (2) and the vacuum chamber barrel (31). 9.Pump according to any one of the preceding claims, in which the vacuum chamber (Cd) defines a maximum axial stroke between its minimum volume state and its maximum volume state, this maximum axial stroke being broken down into: - a major stroke from the maximum volume state, which is induced by the vacuum prevailing in the vacuum chamber (Cd), and - a minor stroke up to the maximum volume state, which is induced by rotational and / or axial driving of the pusher (P), which ends with an axial locking position of the pusher (P). * * *.

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