Pump module, discharge head and fluid dispenser

Abstract

Pump modules (10) for liquid dispensers (100) are known from the prior art. A particular type of such pump module (10) includes a pump cylinder (14) having a fluid inlet (16) at one end and having an inlet valve (18), a rod (40) and a piston (44) attached to the rod (40), the piston (44) being located within the pump cylinder (14) and defining a pump chamber (30) with the pump cylinder (14), the rod (40) extending out of the pump cylinder (14) and including an outlet passage (46) of the pump module (10). The pump module (10) comprises a return spring in the form of a bellows spring (50) or a dome spring (51) by which the rod (40) and the piston (44) are pressed in the direction of the unactuated end position, the bellows spring (50) or the dome spring (51) being supported with a first end surface (56) by the rod (40) or a support collar fixedly attached thereto, and is supported with a second end surface (58) by the pump cylinder or a support collar (20) fixedly attached to the pump cylinder (14). According to the invention, a ventilation path (4) is provided, via which the interior (52) of the bellows spring (50) or dome spring (51) is connected to the surrounding atmosphere, the ventilation path (4) at least partially passes through at least one ventilation hole (64) or at least one end-side recess (62) in the bellows spring (50) or dome spring (51) and / or through at least one ventilation channel (24) or at least one ventilation groove (26) in a support collar (20) attached to the pump cylinder (14).

Description

Technical Field

[0001] The present invention relates to a pump module used as part of a fluid dispenser, and a discharge head and a fluid dispenser comprising such a pump module. The pump module according to the present invention is used, for example, in a fluid dispenser for body lotion and a fluid dispenser for other cosmetic products or liquid medicine. Background Art

[0002] This type of pump module is intended to be combined with a liquid reservoir. A pump rod with a piston can move in a pump cylinder of the pump module. An applicator unit is attached to the rod, which has a discharge opening. When the applicator unit is pressed down, the rod and the piston attached thereto are pressed into the pump chamber of the pump module. The size of the pump chamber is therefore reduced, and the liquid from the pump chamber flows to the applicator unit through an outlet channel in the rod and is discharged there through at least one discharge opening.

[0003] In conventional pump modules, the return force that pushes the rod and the piston back to the initial position after actuation is achieved by means of a metal helical spring acting between the applicator unit and the pump cylinder.

[0004] In order to improve the recovery of such pump modules, it is known to design the return spring as a plastic spring. In addition to plastic spiral springs, various circumferential closing springs have been proposed, which at least substantially isolate the interior of the spring from the external environment. Such springs also include bellows springs and dome springs. For example, pump modules with such springs are known from WO 2021 / 206255 A1 and US 10,335,816 B1.

[0005] Although such closing springs provide very good return properties, they have the disadvantage that during the depression and return movement of the applicator unit, the air in its interior can be compressed or decompressed due to deformation and thus have a negative effect on the spring properties. In addition, such closing springs make it more difficult to ventilate the interior of the bottle of the liquid dispenser. Summary of the invention

[0006] The object of the present invention is to provide a pump module of the above-mentioned type which, despite the use of a circumferential closing spring, can prevent the generation of excessive positive or negative pressure in the closing spring during the downstroke and backstroke of the pump piston and, if the pump module is properly designed, can also ventilate the liquid reservoir through the pump module.

[0007] In order to achieve this, a pump module is proposed, which includes a pump cylinder having a fluid inlet and an inlet valve at one end. The pump module also includes a rod and a piston attached to the rod. The piston is located in the pump cylinder and defines a pump chamber together with the pump cylinder. The rod extends out of the pump cylinder and includes an outlet channel of the pump module. The rod and the piston can be moved relative to the pump cylinder from an unactuated end position with a maximum volume of the pump chamber to an actuated end position with a minimum volume of the pump chamber so as to press the fluid out of the pump chamber into the outlet channel surrounded by the rod. The fluid is directed to an applicator unit and distributed through at least one distribution opening of the applicator unit.

[0008] Typically, the pump module comprises an outlet valve located downstream of the pump chamber. In an advantageous embodiment, the outlet valve is provided by a piston that can be moved in a limited manner relative to the rod. Depending on the relative position of the piston relative to the rod, the pump chamber is connected to the outlet channel in the rod or is separated from the outlet channel in the rod. When the rod is pressed downwards in the direction of the pump chamber, the piston moves relative to the rod to open the outlet channel. During the post-stroke, the negative pressure in the pump chamber causes the piston to move in the opposite direction relative to the rod, thereby closing the outlet valve and the outlet channel.

[0009] The pump module comprises a return spring in the form of a substantially circumferential closing spring around the rod. In particular, the closing spring can be a bellows spring or a dome-shaped spring. The closing spring acts as a return spring and presses the rod and the piston in the direction of the unactuated end position.

[0010] The closing spring is supported with a first end surface by a rod or a supporting collar fixedly attached to the rod, which supporting collar is not part of the applicator unit connected to the rod. However, it is preferred that the rod itself and therefore in particular the exact element extending into the pump cylinder directly supports the outer first end surface of the closing spring. The second end surface on the opposite side of the closing spring is supported by the pump cylinder or a supporting collar fixedly attached to the pump cylinder. In particular, the second end can be supported by a collar fixed at the upper open end of the pump cylinder.

[0011] Due to the fact that the closing spring is supported on both sides, a specific method is required for ventilating the interior of the closing spring. According to the invention, a ventilation path is provided, through which the interior of the closing spring, in particular the interior of a bellows spring or a dome-shaped spring, is connected to the surrounding atmosphere.

[0012] According to a first variant, the ventilation path at least partially passes through at least one ventilation hole or at least one end-side recess in the closing spring, in particular in the end region of a bellows spring or a dome spring.

[0013] According to a second variant, the ventilation path passes through at least one ventilation channel or at least one ventilation groove in a support collar attached to the pump cylinder.

[0014] Both variants allow easy exchange of air between the interior space of the basic closing spring and the outside atmosphere. In order to provide a sufficiently wide total ventilation path, different approaches can be combined. For example, ventilation channels in the closing spring itself and in the support collar can be combined.

[0015] The basic closing spring is preferably designed as a bellows spring. In the bellows portion of the bellows spring, a spiral folding protrusion or a plurality of annular folding protrusions are provided, which allow the length of the bellows spring to be changed when the bellows spring is elastically compressed.

[0016] In a preferred embodiment according to the first variant listed above, the bellows spring has an annular end surface which is interrupted by at least one recess to form a ventilation path. At least one recess extends from the closing spring interior space to the outside of the closing spring, allowing air to use these recesses as a ventilation path. If the closing spring is shortened by pressing the applicator unit, the air in the closing spring is discharged through the at least one recess. If the force applied to press the applicator unit and compress the closing spring ends, the inherent recovery of the elastically deformed closing spring will stretch the spring again and press the rod again into its original position, while the internal space of the spring becomes larger and air is sucked into the interior through the at least one recess.

[0017] The appropriate number and size of the recesses depends on the internal volume of the closing spring. Typically, the number of recesses is 2 to 6 and the total cross-section of all recesses together is 4 mm 2 Up to 30mm 2 , which finds a good compromise between a wide enough ventilation path and maintaining sufficient stability of the closing spring.

[0018] Since the annular end surface of the closing spring is required for supporting the closing spring, it is preferred that the annular end surface is interrupted by a recess to a maximum of 30%, preferably a maximum of 20%, of its circumference. If a larger recess is required to allow more air to be discharged and / or sucked in quickly, the end of the closing spring is preferably designed to have a larger wall thickness. In particular, the bellows spring preferably has an end collar at the end, on which an end surface with at least one recess is provided, the wall thickness of the end collar being greater than the wall thickness of the longitudinal center portion of the closing spring, in particular the wall thickness of the deformable bellows portion of the bellows spring, preferably the wall thickness of the end collar is at least twice the wall thickness of the center portion or the bellows portion.

[0019] If a larger recess is provided on the annular end surface of the bellows spring or dome-shaped spring, it may be advantageous to provide means for preventing the interrupted annular surface from folding outwards. Therefore, it may be advantageous for the pump module to comprise a support surface for supporting the interrupted end surface of the spring, the support surface comprising an outer retaining wall which prevents or limits radial expansion of the bellows spring or dome-shaped spring in the region of the support surface. In particular, the support surface for supporting the interrupted end surface may be provided on a support collar attached to the pump cylinder.

[0020] The at least one end-side recess in the end surface of the bellows spring or dome-shaped spring may have a cross section of a single size. However, it has been found to be advantageous to design the at least one recess such that the cross section of the recess tapers from the inside of the bellows spring or dome-shaped spring to the outside thereof. The tapering design of the recess facilitates the outflow of air when the spring is compressed, while still providing the spring with greater stability than a spring with a non-tapered recess of relatively large size.

[0021] Although a recess on at least one of the end surfaces of the bellows spring or the dome spring provides good possibilities for venting air during compression of the spring, it may be a good alternative to provide at least one ventilation hole through the wall of the bellows spring or through the wall of the dome spring instead. Such a ventilation hole is designed as a through hole which is circumferentially surrounded by the material of the substantially closed spring.

[0022] Using such a design with at least one through hole means that the end surface of the spring does not have to be interrupted by a recess and therefore ensures greater stability. In particular, if a relatively wide ventilation path is required, a design with a recess in the end surface of the closing spring may represent a serious weakening. In this case, a ventilation hole or multiple ventilation holes may be a better approach.

[0023] The bellows spring usually has a center or central bellows portion with a folded protrusion and collars at both ends. When the bellows spring is compressed, this compression only or mainly occurs in the central bellows portion, while the end collars of the bellows spring are not deformed or deformed less.

[0024] At least one ventilation hole may be provided in the bellows portion. However, since the bellows portion deforms primarily and since the behavior of this portion may be negatively influenced by the hole, it is preferred to provide at least one ventilation hole in the bellows collar of the bellows spring at one end of the bellows spring. With respect to the length of the spring, the at least one ventilation hole is preferably provided in an end section of the spring, the length of which corresponds to 10% of the total spring length in the relaxed state.

[0025] Bellows springs are usually manufactured by injection molding, using two slides that define the outer contour of the bellows spring and by using an inner core that defines the inner contour of the bellows spring. After injection and solidification of the material, the slides are moved away from the core in opposite directions for subsequent demoulding.

[0026] Since it is advantageous to define the holes by protrusions provided on the slide, and since the holes move in opposite directions during demolding of the bellows spring, in the case of multiple ventilation holes, it is preferred that these ventilation holes have parallel extension directions for easy demolding, even if the extension direction of some ventilation holes is different from the radial direction.

[0027] Demolding of a bellows spring is usually performed using air to separate the bellows spring from the core defining the inner contour. In order to avoid that the air used for separation leaves the bellows spring through the vents during demolding, preferably a vent hole or a recess is provided at the opposite end, and in particular in the bellows collar at the opposite end. Usually, the bellows spring has a demolding edge on the side from which the separation air is provided. Therefore, the vent hole or the recess is preferably provided at the opposite end, while the bellows collar on one side of the demolding ring is not interrupted by the recess or the vent hole.

[0028] As initially mentioned, the ventilation path can not only be provided in the bellows spring or dome spring. In addition or as an alternative, a pump module with a support collar can also be provided on the pump cylinder, the support collar having a support surface on the upper side for supporting the bellows spring or dome spring. This support collar can also be used to provide the ventilation path.

[0029] Like a bellows spring or a dome spring, the ventilation paths in the support collar can be provided in the form of grooves or in the form of holes designed as through-holes.

[0030] In the case of a support collar with at least one groove, the groove is provided in the contact surface, wherein in the region of the groove the end surface of the bellows spring or dome-shaped spring does not bear against the support collar. Preferably, a plurality of grooves are provided in the contact surface of the support collar, preferably between 2 and 6 grooves.

[0031] In a preferred embodiment, an outer retaining wall is provided on the outside of the support surface for retaining the lower end collar of the bellows spring or dome spring located within the outer retaining wall. The outer retaining wall supports the spring at its lower end and prevents it from breaking.

[0032] In principle, it is possible to make the retaining wall closed in the circumferential direction. In this case, the air flowing through the grooves in the support surface can flow upwards inside the outer retaining wall and into the surroundings. However, this requires that a gap at least partially remains between the outer side of the bellows spring or dome spring and the inner side of the retaining wall.

[0033] On the contrary, advantageous design is provided that at least one groove and preferably a plurality of grooves extend into and through the outer retaining wall.Therefore, air can be exchanged with lower flow resistance between the inner region of the spring and the surrounding atmosphere.

[0034] Preferably, the grooves in the region of the support surface and in the region of the retaining wall have a groove base which is uniformly parallel to the support surface. This facilitates the manufacture of the injection mold for producing the component.

[0035] The outer retaining wall is preferably provided with an inner entry bevel, which facilitates the insertion of the lower collar of the spring during assembly. In particular, it is advantageous if the lower collar rests against the inner side of the retaining wall in a circumferential manner (except for the groove area) and is preferably held there in a clamping manner. In particular for such an embodiment, the provision of an entry bevel is very advantageous.

[0036] The outer retaining wall does not need to be closed in the circumferential direction (except in the region of the grooves), but can also be formed by a crown-like structure with a plurality of different retaining sections. Preferably, however, the outer retaining wall is designed as a circumferential wall which is interrupted only in the region of the grooves. At least one groove or a plurality of grooves together span a maximum of 20% of the circumference of the wall.

[0037] In the case where at least one ventilation channel is provided in the support collar, the one or more ventilation channels penetrate the support collar. One end of such ventilation channel is arranged on the inner side of the support collar, adjacent to the inner space of the bellows spring or the inner space of the dome spring, while the second end of the ventilation channel is arranged on the outer side of the support collar.

[0038] The use of a support collar for ventilation has the advantage that the spring element, in particular a bellows spring, can be left unmodified and completely closed. Thus, the bellows spring that has proven itself in the past can be used without any adjustments.

[0039] In addition to the pump module itself, the present invention also relates to a discharge head. The discharge head comprises a pump module of the above-mentioned type and a base for attaching to a liquid reservoir. The base can be formed integrally with the pump cylinder, but a preferred design is a separate component that connects the base and the pump cylinder to each other. In addition, the discharge head comprises an applicator unit with a discharge opening, for example a discharge opening for discharging liquid in the form of a jet or in the form of a spray cone. The discharge head is connected to the rod of the pump module so as to be pressed down and thus compress the fluid in the pump chamber.

[0040] The applicator is connected to the rod in order to actuate the pump module. However, it is important to point out that the applicator unit does not have the task of supporting the closing spring. The spring is supported by components of the pump module itself, not by an additional component such as the applicator unit.

[0041] The present invention relates to a fluid dispenser for dispensing fluids, in particular for dispensing cosmetic products. The fluid dispenser comprises a fluid reservoir, preferably a fluid reservoir with a volume of 500 ml or less, in which the cosmetic fluid is stored. The fluid dispenser also comprises a discharge head with a pump module. The pump module is designed as a pump module according to the above description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Further advantages and aspects of the invention are described and demonstrated in the claims and in the following description of preferred embodiments of the invention, which will be explained below with reference to the drawings.

[0043] Figure 1 A fluid dispenser having a pump module according to the invention is shown.

[0044] Figure 2 and 3 A pump module with a bellows spring is shown in a perspective view and in a cross-sectional view.

[0045] Figure 4 and 5 A first variant of the ventilation of a bellows spring is shown.

[0046] Figure 6 A second variant of the ventilation of the bellows spring is shown.

[0047] Figure 7 A third variant of the ventilation of the bellows spring is shown.

[0048] Figure 8 A fourth variant of the ventilation of a bellows spring is shown.

[0049] Fig. 9 A fifth variant of the ventilation of the bellows spring is shown.

[0050] Fig.10 and Fig.11 Pump modules according to the invention are shown with different spring types, namely a bellows spring and a dome spring.

[0051] Figures 12 to 15 A further version of a pump module according to the invention is shown. DETAILED DESCRIPTION

[0052] Figure 1 A liquid dispenser 100 for dispensing liquids, in particular for dispensing cosmetic liquids such as soaps, body lotions, etc., is shown, which has a pump module 10 . Figure 2 and Figure 3 The pump module 10 is shown in an isolated view, wherein Figure 3 A cross-sectional view thereof is shown.

[0053] The liquid dispenser 100 has a liquid reservoir 102 having a cup-shaped structure in which liquid is stored before being discharged. Preferably, the fluid reservoir 102 has an internal volume of 200 ml or less. Figure 1 The fluid reservoir shown in is a vented fluid reservoir, ie, air enters the fluid reservoir after the fluid is discharged to avoid negative pressure in the reservoir. As an alternative, the fluid reservoir may have a flexible volume, for example, by using a flexible bag or a follower piston to have a fluid reservoir.

[0054] The liquid dispenser 100 further comprises a discharge head 110, which comprises a base 112, a pump module 10 and a discharge unit 114. The base 112 forms a cover for the fluid reservoir 102 and a support for the pump module 10. In the example, the pump module 10 is coupled to the base 112, for example by means of a snap connection or a threaded connection. However, the base 112 may also be designed integrally with a part of the pump module 10, in particular with the pump cylinder 14 of the pump module 10.

[0055] In addition to the above-mentioned pump cylinder 14, the pump module 10 (which will be described in further detail below) has a rod 40 that extends into the pump cylinder 14 from above and has a piston 44 attached to its lower end. The rod 40 extends upwardly out of the pump cylinder 14 and forms a support for a discharge unit 114, which can be attached to the upper end of the rod 40 by means of, for example, screws or snap connections. The fluid discharged from the pump module 10 reaches the discharge unit 114 through an outlet channel 46 in the rod 40.

[0056] The discharge unit 114 has a discharge opening 116, which is shown in simplified form in the figure. However, the discharge opening 116 can also be designed with a more complex geometry, with a fine nozzle opening or an outlet valve, in order to influence the discharge and, for example, to generate a spray jet.

[0057] The pump module 10 has the above-mentioned pump cylinder 14, which extends into the fluid reservoir 102 and is provided at its lower end with a fluid inlet 16. Preferably, the fluid inlet 16 is preceded by a dip tube 104 extending into the bottom area of ​​the fluid reservoir 102. An inlet valve 18 is provided at the fluid inlet 16, which in the embodiment shown is realized by a ball valve comprising a movable ball which closes the fluid inlet 16 to allow discharge when there is a positive pressure in the pump cylinder 14 and which opens to allow fluid to flow from the reservoir 102 into the pump cylinder 14 when there is a negative pressure in the pump cylinder 14.

[0058] A movable piston 44 is arranged inside the pump cylinder 14. In the present case, the piston is essentially formed by a piston sleeve which is attached in a limitedly movable manner to the rod 40. The piston 44 delimits, together with the pump cylinder 14, a pump chamber 30 which is reduced in size during the discharge of the fluid and which is enlarged during the retraction stroke of the rod 40 and the piston 44 for the subsequent suction of liquid from the fluid reservoir.

[0059] The piston 44 is movably attached to the rod 40 to prevent and allow fluid to be discharged from the pump chamber 30 into the outlet channel 46 leading to the applicator unit 114. When the rod 40 is depressed, the piston 44 is displaced upward relative to the rod 40 to allow fluid to flow from the pump chamber 30 into the outlet channel 46 and to the discharge opening 116. When the rod 40 is displaced upward during the return stroke, at the beginning of this movement, the piston 44 is displaced relative to the rod to a lower end position, isolating the pump chamber 30 from the outlet channel 46, thereby generating a negative pressure in the pump chamber 30, which opens the inlet valve 18 and draws fluid from the fluid reservoir 102 into the pump chamber 30.

[0060] The pump module 10 is designed with easy recycling in mind. Therefore, it preferably comprises only plastic parts, preferably plastic parts that can be processed in a single recycling stream.

[0061] In particular, the pump module has a plastic return spring 50 instead of a metal return spring. The plastic return spring 50 is designed as a substantially closed, hose-like spring which can be axially compressed to resist the return force. The return spring 50 is arranged around the central portion of the rod 40, between the pump cylinder 14 or the support collar 20 attached thereto on the one hand and the upper end region of the rod 40 on the other hand, and is supported at the ends by said components.

[0062] Since the support surfaces 22, 42 for supporting the return spring 50 at both ends are therefore a direct part of the pump module 10, the latter can be easily handled during assembly. The fact that the return spring 50 is a quasi-internal component of the pump module 10 facilitates the assembly of the pump module 10, the fluid reservoir 102 and the discharge unit 114, since the return spring 50 does not have to be handled separately during assembly of the dispenser 100.

[0063] The return spring 50 is designed as a circumferentially closed spring to produce a relatively large achievable return force and a good repeatable behavior of the spring. In the present embodiment, the return spring 50 is designed as a bellows spring, which has spiral or circumferentially folded protrusions in the central bellows section 50C, which protrusions approach each other when the rod 40 is pressed down and deform elastically in the process. Bellows end collars 50A, 50B are arranged at both ends of the bellows spring 50, which are relatively thick and therefore do not deform or hardly deform when the spring 50 is compressed. In addition to being a bellows spring 50, the return spring can also have another basic closed spring design. In particular, a dome-shaped spring is an alternative.

[0064] Due to the substantially circumferentially closed shape of the return spring 50, it encloses an annular inner space 52 which is bounded on the outside by the return spring 50 and on the inside by the outer side of the rod 40. When the piston 44 is pressed down, the air located therein is compressed. During the upward movement of the rod 40, the inner space is enlarged, so that a negative pressure is generated therein.

[0065] This positive pressure during depression and negative pressure during retraction constitute a disadvantage, since they may negatively influence the spring behavior of the return spring 50. It is therefore provided that the inner space 52 of the return spring 50 is connected to the environment outside the pump module 10 and outside the fluid dispenser 100 via a ventilation path. This serves not only to allow air to flow out of and into the inner space 52 of the return spring 50, but also in fluid dispensers with a ventilated fluid reservoir (e.g. Figure 1 In the case of one of the above, this communication connection can also be used to ventilate the bottle.

[0066] Figure 4 and Figure 5 A first variant for realizing a ventilated connection between the surrounding atmosphere and the spring interior 52 is shown. It is provided here that a recess 62 is formed in the end surface 58 of the lower bellows collar 50B of the return spring 50. In this case, a total of six recesses offset by 60° from one another are provided. Between the radial recesses 62 there remain support areas 61, with which the bellows spring rests on the support surface 22. The recesses 62 reduce the support surface by only about 25%. It may be useful to design the bellows collar 50A with a greater width to compensate for this.

[0067] As Figure 4 As shown, when the rod 40 is pressed down, air can escape from the spring interior space 52 via the ventilation path 4 through the recess 62 .

[0068] In principle, it is also possible to provide the recess 62 not only at the lower bellows collar 50A, but alternatively or additionally at the upper bellows collar 50B of the bellows spring 50. However, this is considered disadvantageous in the present case for the following reasons. The manufacture of the closing spring for the present invention is usually done by an injection molding process, in which the inner core keeps the spring free of material. The spring is usually released after the material solidifies with the aid of air. However, if recesses or openings are provided at both ends of the return spring, it is difficult to supply air between the core and the return spring to demould the return spring. Therefore, preferably, the recess 62 or the ventilation hole 64 is only provided on one end face or in one end region of the return spring 50. The recess 62 is preferably provided on the side opposite to the spring side comprising the demoulding edge 54.

[0069] The flow resistance through the recess 62 is relatively high due to the shape of the bellows collar 50A and the support collar 20 attached to the pump cylinder 14. This may result in air not being able to escape from the spring interior space 52 to the desired extent during the brief start-up period, or not being able to flow in quickly enough during the return stroke.

[0070] Figure 6 A design is shown in which the recess 62 has a modified shape to improve the flow behavior of the air. The recess 62 here widens inwards. It has been found that, despite the Figure 5 Their narrowest cross section does not change compared to the design of the spring, but this widening allows a significantly improved outflow of air from the spring interior 52 of the spring during depression of the rod 40.

[0071] In many applications, a design having a recess 62 on one of the end surfaces 56, 58 of the closing spring 50 is considered a good way to allow ventilation of the return spring 50. However, providing a recess in the end surface 56, 58 can be a disadvantage because it reduces the contact area of ​​the return spring and makes the spring 50 unstable.

[0072] Therefore, an alternative solution was designed, such as Figure 7 Here, no recess 62 is provided in the end face 58. Instead, a total of six ventilation holes 64 are provided in the lower bellows collar 50A, i.e. through holes 50 surrounded by the material of the return spring. Thus, the annular end surface 58 of the return spring 50 is uninterrupted.

[0073] The ventilation holes can each have a different extension direction. However, preferably, they are aligned parallel to each other. This uniform alignment allows easy production, since the ventilation holes 64 can be kept free during injection molding by pins, which are provided on two side slides of the injection molding tool, which are spaced apart from the core of the injection mold in opposite directions during demoulding.

[0074] Figure 8 and Fig. 9 An alternative design of a ventilation path is shown. Here, a support collar 20 arranged to be attached to the upper end of the pump cylinder 14 has a shape by which this ventilation path is created.

[0075] exist Figure 8 In the case of a design of , a ventilation groove 26 is provided in the support collar 20, which passes through the support surface 22 of the support collar 20. The illustrated design only provides one ventilation groove 26. On the contrary, it is also possible to provide a plurality of such ventilation grooves 26, preferably three or more grooves 26 evenly distributed around the circumference. Although Figure 5 and Figure 6 This reduces the contact area between the support surface 22 and the end surface 58 of the return spring 50, but the design with the ventilation groove 26 in the support collar 20 can be advantageous because the deformation of the return spring 50 itself is not affected by the ventilation groove 26. Therefore, a standard bellows spring can be used without modification.

[0076] Fig. 9 An alternative is shown, in which the support collar 20 also provides ventilation. However, it is provided here that no ventilation groove is provided on the upper side, but at least one ventilation channel 24 designed as a through hole is provided instead. In addition to a single ventilation channel 24, a plurality of ventilation channels 24 can also be provided. For ease of manufacture, in the case of providing a plurality of ventilation channels 24, the ventilation channels 24 are preferably aligned parallel to each other.

[0077] Fig.10 The pump module 10 is again shown in a cross-sectional view with the bellows spring 50. In the illustrated design, ventilation holes 64 and ventilation channels 24 are provided in the bellows spring 50 and in the support collar 20 for ventilation purposes.

[0078] Fig.11 It is shown that the ventilation concept according to the invention is not limited to bellows springs. Fig.11 In the design, a dome-shaped spring 51 is used instead. Fig.10 Like the bellows spring 50 , both the support collar 20 and the spring collar 51A at the lower end of the spring 51 are provided with ventilation holes 64 and ventilation channels 24 .

[0079] Figures 12 to 15 Another embodiment of a pump module 10 according to the invention is shown. Figure 8 As in the design, Figures 12 to 15 This variant has grooves 26 in the support surface 22. In the variant shown, six such grooves 26 are provided, but more or fewer grooves may also be provided. It is also possible that Figure 8 The design has only one groove 26 .

[0080] Fig.12 The complete pump module 10 is shown. Fig.13 In the embodiment shown in FIG. 2 , the bellows spring 50 is hidden so that the groove 26 can be more easily identified. Fig.14 shows a cross-sectional view of the upper part of the pump module 10, and Fig.15 Another cross-sectional view of the airflow path 4 is provided in detail.

[0081] according to Figures 12 to 15 A relevant feature of the variant is that an outer retaining wall 27 is provided on the outside of the support surface 22. By means of said outer retaining wall 27, the lower end collar 50A of the return spring 50 is supported on the outside. The groove 26 extends through the outer retaining wall 27 in order to allow an easy airflow between the inner space 52 of the return spring 50 and the environment.

[0082] As an alternative to the upwardly open recesses, through-bores can also be provided in the outer retaining wall 27 , which penetrate the retaining collar and communicate with the recesses 26 in the support surface 22 .

[0083] The outer retaining wall 27 is adjusted so that the lower end collar 50A rests against it with its outer circumference in the circumferential direction, or only a narrow gap remains here. Figures 12 to 15 In the case of the variant of the embodiment, the lower end collar 50A is fixed in a clamping manner by the outer retaining wall 27. In order to facilitate assembly, the upper end of the outer retaining wall 27 is provided with an entry chamfer on its inner side.

[0084] In a variant not shown, in which a gap remains between the outer side of the end collar 50A and the inner side of the outer retaining wall 27, it is preferred that the clear width of the gap is smaller than the clear width on the inner side of the bellows collar 50A when the return spring 50 is in the centered position.

[0085] Fig.14 and 15 A path 4 is shown along which air can be exchanged between the interior space 52 of the return spring 50 and the external environment. With the small flow resistance provided by said path 4 and with six of these grooves 26, it is ensured that air can escape easily when the bellows spring 50 is compressed.

Claims

1. A pump module (10) for a liquid dispenser (100), having the following characteristics: a. The pump module (10) comprises a pump cylinder (14) having a fluid inlet (16) at one end and having an inlet valve (18); and b. the pump module (10) comprising a rod (40) and a piston (44) attached to the rod (40), the piston (44) being located within the pump cylinder (14) and defining a pump chamber (30) together with the pump cylinder (14), the rod (40) extending out of the pump cylinder (14) and comprising an outlet passage (46) of the pump module (10); and c. the rod (40) and the piston (44) are movable relative to the pump cylinder (14) from an unactuated end position where the volume of the pump chamber (30) is maximum to an actuated end position where the volume of the pump chamber (30) is minimum so as to press the fluid out of the pump chamber (30) into the outlet passage (46), and d. the pump module (10) comprises a return spring in the form of a bellows spring (50) or a dome spring (51), by means of which the rod (40) and the piston (44) are pressed in the direction of the unactuated end position, the bellows spring (50) or the dome spring (51) being supported with a first end surface (56) by the rod (40) or a support collar fixedly attached to the rod, and with a second end surface (58) by the pump cylinder or a support collar (20) fixedly attached to the pump cylinder (14), Features The following additional features: e. A ventilation path (4) is provided, through which the inner space (52) of the bellows spring (50) or the dome spring (51) is connected to the surrounding atmosphere, and the ventilation path (4) at least partially passes through at least one ventilation hole (64) or at least one end-side recess (62) in the bellows spring (50) or the dome spring (51) and / or through at least one ventilation channel (24) or at least one ventilation groove (26) in a supporting collar (20) attached to the pump cylinder (14).

2. The pump module (10) according to claim 1 has the following features: a. The return spring is designed in the form of a bellows spring (50), and b. The bellows spring includes a bellows portion (50C), wherein the bellows spring (50) includes a spiral folded protrusion or a plurality of annular folded protrusions, and when the bellows spring (50) is compressed, the spiral folded protrusion or the plurality of annular folded protrusions allow the length of the bellows portion (50C) to change.

3. The pump module (10) according to claim 1 or 2, having the following characteristics: a. at least one end of the bellows spring (50) or the dome-shaped spring (51) has an annular end surface (56, 58) interrupted by at least one recess (62) to form the ventilation path, Preferably, it has at least one of the following additional features: b. The bellows spring (50) or the dome spring (51) has a plurality of recesses (62) interrupting the annular end surface (56, 58), preferably between 2 and 6 recesses, and / or c. the annular end surface (56, 58) is interrupted by the recess by at most 30% of its circumference, preferably at most 20%, and / or d. The bellows spring (50) has a bellows collar (50A) at the end on which the end surface (56, 58) is provided, and the wall thickness of the bellows collar (50A) is greater than the wall thickness of the bellows portion (50C) of the bellows spring (50), and preferably the wall thickness of the bellows collar (50A) is twice the wall thickness of the bellows portion (50C).

4. The pump module (10) according to claim 3 has the following characteristics: a. The pump module comprises a support surface (22) for supporting the interrupted end surface (56, 58), and b. The support surface (22) comprises an outer retaining wall which prevents or limits radial expansion of the bellows spring (50) or the dome spring (51) in the region of the support surface (22).

5. The pump module (10) according to claim 2 or 3, having at least one of the following features: a. The pump module comprises a support surface (22) for supporting the interrupted end surface (56, 58), and b. The support surface (22) is provided on a support collar (20) attached to the pump cylinder (14).

6. The pump module (10) according to claim 2 or 3, having the following features: a. The cross section of the recess (62) gradually tapers from the inside of the bellows spring (50) to the outside thereof.

7. The pump module (10) according to claim 1 or 2, having the following features: a. the bellows spring (50) or the dome-shaped spring (51) has at least one ventilation hole (64), the at least one ventilation hole being circumferentially surrounded by the material of the bellows spring (50) or the dome-shaped spring (51), Preferably, it has at least one of the following additional features: b. The bellows spring (50) or the dome-shaped spring (51) has a plurality of ventilation holes (64), and / or c. the at least one ventilation hole (64) is provided in the bellows portion (50C) of the bellows spring (50), or d. The at least one ventilation hole (64) is provided in the bellows collar of the bellows spring (50) at one end of the bellows spring (50).

8. The pump module (10) according to claim 7, having the following features: a. A plurality of ventilation holes (64) are provided in the bellows spring (50) or the dome-shaped spring (51), and the ventilation holes (64) have parallel extension directions.

9. The pump module (10) according to any one of the preceding claims, characterized in that: a. The bellows spring (50) or the dome-shaped spring (51) has an inwardly directed demoulding edge (54) at one end, and the demoulding edge (54) is preferably arranged at the end opposite to the interrupted end surface (58).

10. The pump module (10) according to claim 1 or 2, having the following features: a. the support collar (20) on the pump cylinder (14) has a support surface (22) on the upper side for supporting the bellows spring (50), and b. The support collar (20) has at least one groove (26) in a contact surface (22) forming a part of the ventilation path (4), wherein In the region of the groove (26), the end surfaces (56, 58) of the bellows spring (50) do not bear against the support collar (20), Preferably has the following additional features: c. The support collar (20) has a plurality of grooves (26), preferably between 2 and 6 grooves (26), in the contact surface.

11. The pump module (10) according to claim 10, characterized in that: a. the support surface (22) comprises an outer retaining wall (27) for retaining the lower end collar (50A) of the bellows spring (50) or the dome spring (51) in the region of the support surface (22), and b. said at least one groove (26) penetrates said outer retaining wall (27), Preferably has the following additional features: c. In the region of the contact surface (22) and in the region of the outer retaining wall (27), the groove has a groove base which is uniformly parallel to the contact surface (22).

12. The pump module (10) according to claim 10 or 11, having the following features: a. The outer retaining wall (27) is provided with an inner entrance bevel for inserting the lower end collar (50A) of the bellows spring (50) or the dome-shaped spring (51).

13. The pump module (10) according to claim 10, 11 or 12, having the following features: a. the outer retaining wall (27) is designed as a circumferential wall which is interrupted only in the region of the groove (26), and b. The at least one groove (26) spans a maximum of 20% of the wall circumference of the outer retaining wall (27).

14. The pump module (10) according to any one of claims 10 to 13, having the following features: a. The lower end collar (50A) is in circumferential contact with the inner side of the outer retaining wall (27), except in the region of the at least one groove (26).

15. The pump module (10) according to claim 1 or 2, having the following features: a. Providing at least one ventilation channel (24) penetrating the support collar (20).

16. Pump module (10) according to any of the preceding claims, characterized in that: a. The piston (44) is movable relative to the rod (40) in a limited manner, wherein the piston (44) and the rod (40) together form an outlet valve that can be opened and closed by the relative movement of the piston (44) relative to the rod (40).

17. A discharge head (110) for a liquid dispenser (100), having the following features: a. The discharge head (110) comprises a base (112) for attaching to the liquid reservoir (102), and b. the discharge head (110) comprises an applicator unit (114) having a discharge opening (116), the applicator unit (114) being movable relative to the base (112) for a pumping motion, and c. the discharge head (110) comprises a pump module (10) which is attached to or forms the base (112) on the one hand and to which the applicator unit (114) is attached on the other hand, Features The following additional features: d. The pump module (10) is designed according to any of the preceding claims.

18. A fluid dispenser (100) for dispensing a fluid, in particular for dispensing a cosmetic product, having the following features: a. The fluid dispenser (100) comprises a fluid reservoir (102), and b. The fluid dispenser (100) comprises a discharge head having a pump module (10), Features The following additional features: c. The pump module (10) is designed according to any one of claims 1 to 16.

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