Pump unit and liquid dispenser with such a pump unit

Abstract

The invention relates to a pump unit (10) for a liquid dispenser (100). Such a pump unit (10) has a pump cylinder (30) and a pump piston (50) which can be moved relative to the pump cylinder (30) between an unactuated end position and an actuated end position. The pump unit (10) also has an inlet valve (16) at the liquid inlet (14) and an outlet valve (20) at the liquid outlet (18) and has a return spring (70) by means of which the pump piston (50) is forced in the direction of the unactuated end position. According to the invention, the return spring (70) is designed as a tension spring and is arranged in such a way that a cylinder-side end (72) of the return spring (70) and a piston-side end (74) of the return spring (70) are spaced apart from one another in the longitudinal direction when the pump chamber (12) is shrunk and a tension state is generated or enhanced in the return spring (70). The return spring (70) is designed at least in sections as a cage spring, which has a wall (77) having a cylindrical or conical basic shape. The wall (77) of the cage spring has a structure formed by perforations (78), said structure having node parts (82) and spring webs (79) connecting the node parts (82).

Description

Technical Field

[0001] The present invention relates to a pump unit for a liquid dispenser and a liquid dispenser having such a pump unit. Background Technology

[0002] Pump units of this type are part of liquid dispensers, such as those used for pharmaceutical liquids or possibly cosmetic liquids. The pump unit is configured to draw liquid from a liquid reservoir and apply pressure to it through a discharge port for discharging purposes. Discharging is particularly in the form of a jet, but can also be done in the form of an unatomized jet or as a single droplet.

[0003] Pump units of this type are typically designed for manual operation, particularly for operation by pressing a control button, which may also have a discharge port.

[0004] Pump units of this type are typically equipped with a return spring that, after manipulation and the associated reduction in the volume of the pump chamber along with the discharge of liquid, presses the pump unit back to its initial position and thereby moves the pump piston back to its initial position.

[0005] Return springs were previously typically constructed as metal springs. However, during this period, plastic springs were used in many liquid dispensers. This facilitated recycling because it eliminated the need to separate the metal components from the plastic.

[0006] As is known from the prior art, a pump unit is provided in which the return spring is integrated in the form of a tension spring. Such a case is illustrated, for example, by US 8622254 B2, US 5267673 A, US 5788124 A, CN 103029895 B, US2002 / 043540 A1 and US 6227414 B1.

[0007] Known systems have a return spring having a parallel, single-segment or surrounding closed sleeve that is stretched when the pump is operated. This design has been shown to be problematic because it is difficult to find materials that allow for comfortable use with respect to the required operating force and the desired return force. As known from US 2002 / 043540 A1, the sleeve is oriented such that the stretch of the return spring is less than the stroke of the pump piston. However, the design described herein is quite large and practically difficult to implement even in a compact dispenser. Summary of the Invention

[0008] The objective of this invention is to provide a pump unit and a dispenser having such a pump unit, wherein the pump unit has a return spring that simultaneously ensures the desired functioning of the pump unit and enables simple recycling.

[0009] According to the present invention, a pump unit for a liquid dispenser and a liquid dispenser having such a pump unit are proposed. The pump unit will be described in detail below. However, these embodiments also relate to a liquid reservoir having such a pump unit.

[0010] The pump unit according to the invention has a pump cylinder and a pump piston, the pump piston being movable relative to the pump cylinder between an unoperated end position and an operated end position. The pump cylinder has a cylindrical sealing surface in at least a partial section, in which the pump piston circumferentially and sealingly abuts against the sealing surface.

[0011] The pump chamber, surrounded by the pump cylinder and pump piston, has its maximum volume in the unoperated terminal position and its minimum volume in the operated terminal position. During the period when the pump chamber volume decreases due to operation, liquid is conveyed from the pump chamber towards the discharge port. During the subsequent return period and the accompanying increase in pump chamber volume, liquid is drawn from the liquid reservoir into the pump chamber.

[0012] The pump unit for this purpose has an inlet valve at the liquid inlet of the pump chamber and a discharge valve at the liquid outlet of the pump chamber. During discharge, the discharge valve is open and the inlet valve is closed. During return, the discharge valve is closed at least partially and the inlet valve is open, allowing liquid to be drawn into the pump chamber through the liquid inlet. As will be further described below, the discharge valve is preferably a valve that opens based on overpressure in the pump chamber. The inlet valve can be opened based on low pressure in the pump chamber or based on distance.

[0013] The pump unit has a return spring by means of which the pump piston is subjected to a force in the direction of its unoperated terminal position. This spring acts between the pump unit housing, or particularly the pump cylinder, and the pump piston, wherein the return spring may also be supported not on the pump cylinder and pump piston, but on a structural element fixed thereto. In particular, the pump piston itself may be an integral part of the return spring, as will be explained below.

[0014] According to the invention, this return spring is designed in a special way. The return spring is constructed as a tension spring according to the invention and arranged such that the cylinder-side end and the piston-side end of the return spring are separated from each other longitudinally when the pump chamber contracts, thereby creating or reinforcing tension in the return spring. Therefore, when operating the pump unit, the piston is separated from the cylinder-side end of the return spring and the support area therein, so that the return spring as a whole is subjected to tensile load.

[0015] The return spring is constructed at least in sections as a cage spring. This means that the area of ​​the return spring constructed as a cage spring, or, if necessary, the entire return spring constructed as a cage spring, has a surrounding wall having a basic cylindrical or conical shape. A perforation is provided in this wall, the perforation having a structure with nodes and spring tabs connecting the nodes.

[0016] It has been shown that the construction of a cage-type tension-reset spring offers significant advantages. Therefore, a weaker tendency to relax can be observed. Furthermore, for cage-type springs, elastic elongation is not solely caused by material tension, but largely by bending deformation. This allows for greater flexibility in selecting spring materials, as materials that produce excessively high operating forces with suitable strength under pure tensile loads can be considered if the reset spring elongates, or primarily, through bending deformation.

[0017] The design of a return spring as a tension spring has the advantage of defining its shape when tensioned by actuation. A problem with compression springs, however, is that they cannot always deflect in a predictable manner, potentially impairing the distributor's function. Cage springs have proven particularly well-suited for ensuring the defined positional characteristics of the return spring during actuation. The deformation of the return spring can be controlled very precisely by targeted reinforcement or weakening of the joints and / or spring contacts.

[0018] Cage springs typically have nodes in their walls, which are conditionally connected by a perforated arrangement to spring tabs having adjacent nodes or to the area of ​​the return spring or adjacent to the cage spring.

[0019] The preferred cage spring has at least four nodes, of which at least three spring tabs extend to other nodes or the area of ​​the return spring adjacent to the cage spring. Particularly preferred are at least eight such nodes, or even twelve or more such nodes.

[0020] The preferred cage spring has spring tabs that are integrally mounted on a common node and are opened during the separation of the ends of the return spring, thereby causing bending deformation in the respective node.

[0021] A return spring having such spring tabs that open under load is preferably shaped such that it stores most of the energy introduced by manipulation in the form of bending deformation, that is, by deformation in which the spring tabs and nodes of the cage spring deform such that upsetting occurs on one side and stretching occurs on the opposite side.

[0022] Especially for springs based on bending deformation, it has been shown that only a small tendency to relax can be recorded with such joints and spring tabs, and spring characteristic curves suitable for pump operation are more easily achieved here compared to springs that store energy entirely or primarily through tensile loads.

[0023] The storage of energy applied during operation does not necessarily occur solely through the bending deformation mentioned in the joints or spring contacts. Furthermore, bending deformation and other elastic deformations may occur in other parts of the return spring. It is considered advantageous that, in the tensioned state of the return spring, with the pump piston positioned in the operated end position, at least 50%, preferably at least 80%, of the spring energy of the return spring is stored in the bending deformation of the joints and spring contacts.

[0024] The cage spring has spring tabs that are freely cut on both sides through perforations, wherein the number of perforations is preferably between 8 and 200, and particularly preferably between 12 and 100. It is preferred to form at least three such spring tabs through the perforations, but in particular, spring tabs with between 12 and 72 perforations are formed.

[0025] The return spring is preferably made at least partially of polyolefin, preferably polyethylene. It is also preferred that the return spring be made entirely of polyolefin. However, it is also possible to specify that the return spring is manufactured as a 2K component. In such cases, it is preferred that at least the cage spring be made of polyolefin.

[0026] The cage spring has a structure consisting of a perforation and a node and spring tabs located therebetween. In the node, the cage spring undergoes elastic deformation by bending as it stretches during operation of the distributor. This bending deformation of the node can also refer to the bending deformation in the transition section of the spring tab directly adjacent to the node. Specifically, two spring tabs integrally connected to the node are connected by a rounded transition portion on the node, which preferably has a minimum rounding radius greater than 0.5 mm, and particularly greater than 1.0 mm. In the context of this invention, this transition radius is considered part of the node.

[0027] The preferred cage spring has a through hole, which is defined by four spring tabs, namely two upper spring tabs and two lower spring tabs. The lower and upper spring tabs each form two spring tabs, which are connected on the side of the through hole by node members. The upper and lower spring tabs form a series of spring tabs, which are interconnected at the center of the through hole by other node members.

[0028] In this case, at least some of the perforations are defined by a total of four node pieces and a total of four spring tabs.

[0029] The cage spring preferably has a surrounding structure consisting of node members and connecting spring tabs, wherein the spring tabs are connected to the node members at both ends, and particularly preferably at least some node members each carry at least two pairs of spring tabs. The node members are preferably arranged in rows along the longitudinal direction, wherein 4, 6, or 8 rows of node members are preferably provided and they are distributed within the periphery of the cage spring.

[0030] At least one of the node members carrying the two pairs of spring tabs preferably has a cross-section in a plane orthogonal to the longitudinal direction, the cross-section having a shape that gradually tapers along the central axis of the return spring. The two side edges of the node member are therefore not oriented parallel, but rather at an angle to each other radially or even beyond the central axis of the cage spring. In particular, the cross-section of the node member can have a triangular cross-section. Depending on the specific shape of the cage spring and the manufacturing process, having opposite orientations with a shape that gradually tapers away from the central axis, or parallel orientations of the side edges, can also be advantageous.

[0031] It has been shown that reducing the stress peak along the central axis reduces the risk of damaging the return spring during pump unit operation.

[0032] Another specific structural configuration specifies the arrangement of multiple circumferentially distributed node elements, which are interconnected by stabilizing rings. Particularly preferred is that the surrounding stabilizing rings are integrally formed with the node elements. The stabilizing rings are preferably connected to the node elements of the cage spring in such a way that no bending or other related deformation occurs within the stabilizing rings when the return spring is stretched.

[0033] Such a stabilizing ring, for a cage spring, helps to connect the nodes arranged on a common geometric plane orthogonal to the longitudinal axis and thus reduces the tendency of the nodes to shift outward or inward during operation. Instead, the positions of the nodes relative to each other remain largely unchanged, and the energy stored in the return spring is stored primarily through the deformation of the spring tabs.

[0034] The perforation, typically surrounded by the node and four spring tabs, can be set in various special shapes.

[0035] A preferred design specifies that the cage spring has perforations that form a net spacing along the longitudinal direction in the side regions, which is greater than the net center distance along the longitudinal direction. The net spacing along the longitudinal direction is preferably zero in the unoperated state of the return spring, meaning that only in the two side regions of the perforations do the opposing faces of the return spring not abut against each other in the unoperated state.

[0036] The described structural form is particularly suitable for achieving a high degree of deformation without damaging the return spring. In the mentioned lateral region, the return spring component preferably has a rounded portion to prevent tearing of the return spring during operation.

[0037] When the pump cylinder and pump piston are arranged in the actuated terminal position, the spring tabs at the common node preferably form an angle that is between 5° and 50° larger than the angle formed by the spring tabs when the pump cylinder and pump piston are arranged in the unactuated terminal position. Preferably, the straight line extending through the node connected by the spring tabs forms an angle of less than 10° with a plane orthogonal to the longitudinal direction in the unactuated state of the pump unit and an angle of greater than 10° in the actuated state.

[0038] The return spring can be connected to the pump piston in various ways. Thus, for example, mechanical coupling can be achieved through a form-locking mechanism using suitable contours on the return spring and pump piston components.

[0039] However, a particularly advantageous design is an integral one, in which the return spring has a piston geometry integrally molded onto its lower end, featuring a surrounding piston lip. This piston lip forms the pump piston and, at least in stages during operation, abuts against the cylindrical pump cylinder on its inner side. This integral design eliminates the need for form-locking or force-locking coupling between the pump piston and the return spring, which is sufficiently stable under tensile loads.

[0040] Here, as a single component, it is possible to not only provide a component made of only one type of plastic, including a piston lip and a spring region with joints and spring contacts, but also a component manufactured by multi-component injection molding to provide specific material properties to different sections of the component. In particular, the cage spring and piston lip can be made of different materials.

[0041] Especially in integrated designs with a one-piece molded piston lip, the return spring can also serve as other functional components. Therefore, the return spring preferably provides the valve face of the discharge valve, against which a valve section of the valve body abuts when the discharge valve is closed. Particularly preferred is that this valve section is configured to expand under liquid overpressure and be lifted away from the valve mating face, thereby enabling liquid discharge.

[0042] A preferred configuration is one in which the pump unit has a discharge pipe extending from the extraction side into the internal region of the return spring. The discharge pipe is preferably fixed relative to the operating handle, by means of which the pump unit is manually operated. Coupling between the return spring and the discharge pipe occurs within the internal region of the return spring. For this purpose, the discharge pipe and the return spring preferably have mutually acting stop surfaces, allowing the return spring to be stretched by means of the discharge pipe when it is pressed down. These stop surfaces can be oriented orthogonally to the direction of movement of the discharge pipe. Particularly advantageously, at least one and preferably two stop surfaces have a tapered or otherwise widened shape. Thus, the stop surfaces can interlock. In this case, the discharge pipe appears to be hooked into the stop surface of the return spring.

[0043] In particular, a discharge valve can be formed when using the type of discharge pipe described or other types. Therefore, the pump unit preferably has a discharge pipe that is inserted into a return spring. A valve member is provided on this discharge pipe. This valve member can be constructed as a separate component that can be fixed to the discharge pipe and, more particularly, inserted therein.

[0044] The valve component preferably forms the valve face of the discharge valve, which, in the closed state, abuts against the region of the lower end of the return spring and / or against the inner surface of the pump piston. When the pressure in the pump chamber is sufficiently high, the return spring or the pump piston elastically expands, thereby losing contact and the discharge valve is opened.

[0045] As an alternative or supplementary option, the valve component can also be part of the inlet valve. For this purpose, it is preferably provided that a liquid inlet is provided in the bottom of the pump cylinder, and a section of the valve component moves into or within the liquid inlet when the discharge pipe is depressed, thereby closing the inlet valve. As will be explained below, this is particularly suitable when a delayed discharge relative to the operation of the pump unit is desired.

[0046] To connect the return spring to the pump cylinder, it is preferably specified that the return spring has at least one outwardly extending support element at one end, in the form of, for example, a surrounding bearing ring, to form a spring seat on the cylinder side. The return spring is fixed to the pump cylinder in the longitudinal direction by means of this support element, wherein abutment surfaces can be provided on the support element and the pump cylinder for this purpose. Preferably, the abutment surfaces on the support element and / or the abutment surfaces on the pump cylinder are orthogonal to the operating direction or have chamfers when a stepped structure is formed, in order to prevent the support element from slipping off the pump cylinder.

[0047] In a preferred design, the pump unit is structured such that it comprises a cylinder housing and a housing cover to form a pump cylinder. The cylinder housing preferably has two cylindrical sections along the longitudinal direction with different inner diameters: a return spring section with a larger diameter for receiving a cage spring and a pump chamber section with a smaller diameter, wherein the diameter of the pump chamber section is at least sectionally matched to the outer diameter of the pump piston to define the pump chamber. The housing cover is configured to close the pump unit upwards, particularly its return spring section. It may have a through-hole through which an operating lever, preferably in the form of a discharge pipe as mentioned above, extends.

[0048] The return spring can be clamped between the cylinder housing and the housing cover. Particularly preferred is that both the housing cover and the cylinder housing have outwardly extending mounting flanges, which abut directly against each other. The abutting mounting flanges allow the two housing components of the pump unit, namely the cylinder housing and the housing cover, to be pressed together and positioned by means of a locking mechanism, for example, a snap-fit ​​element or threaded fastener, fixed to the container of the liquid reservoir. This sufficiently secures the cylinder-side spring seat of the return spring.

[0049] The discharge valve of the pump unit is preferably a pressure-based discharge valve, that is, a valve that opens when the designed limit pressure is reached in the pump chamber.

[0050] The inlet valve can also be configured to open based on pressure, meaning it opens when the pressure in the pump chamber drops sufficiently relative to the pressure in the liquid reservoir to create a negative pressure in the pump chamber. However, in a particular design, the inlet valve is configured to close based on displacement, closing in a designed intermediate position after the idle stroke as the pump piston moves from its unoperated end position toward its operated end position. Furthermore, it can be specified that a closing protrusion, designed to seal the metering passage for closing the inlet valve, reopens the metering passage at the opposite end upon completion of operation, causing the discharge process to end abruptly and in a well-defined manner. This also facilitates the commissioning of the distributor, as air located in or compressed within the pump chamber during commissioning may escape into the liquid reservoir.

[0051] As an alternative to such a stroke-based inlet valve, it is possible to specify that the pump unit has a closable outlet passage through which liquid can flow from the pump chamber back to the liquid reservoir, and that the outlet passage closes only after an empty stroke when the pump piston moves from an unoperated end position toward an operated end position.

[0052] Both design schemes—one with an inlet valve closing after the empty stroke and the other with an outlet passage closing after the empty stroke—prevent discharge initially when the pump unit is operated, for the purpose of returning the liquid from the pump chamber to the liquid reservoir. This is because the liquid in the pump chamber is not yet isolated from the liquid reservoir at the start of operation, and therefore the pressure required to open the discharge valve cannot be established at this point. Only after the empty stroke has elapsed is the pump chamber isolated relative to the liquid reservoir, the pressure in the liquid increases, and the discharge process begins. The empty stroke is at least 5%, preferably at least 10%, of the distance between the operated and unoperated terminal positions of the pump piston.

[0053] The delayed discharge of fluid through the idle stroke is advantageous because it results in the following: even if the return spring has a length different from the target length in the unoperated state due to relaxation or other aging processes, a uniform amount of fluid can be achieved with each operation.

[0054] One feasible solution for implementing an outlet channel of the described type is that the pump cylinder and pump piston are coordinated such that they do not circumferentially abut against each other in the unoperated terminal position, but only after an empty stroke during the movement of the pump piston toward the operated terminal position. Only when circumferentially sealed contact exists can liquid no longer leak from the pump chamber into the liquid reservoir, and continued operation causes liquid discharge.

[0055] The pump cylinder and pump piston are coordinated in such a way that they do not abut against each other in a sealed manner in the unoperated terminal position. This can be achieved by ensuring that the pump piston does not contact the pump cylinder in the unoperated terminal position, thus leaving an annular gap between the inner wall of the pump cylinder and the pump piston. Alternatively, a design is possible in which the pump piston abuts against the inner wall of the pump cylinder in the unoperated terminal position via a partial section of its periphery and is separated from the inner wall of the pump cylinder in another partial section of its periphery, thus forming an outflow channel.

[0056] In both cases, the liquid can leak from the pump chamber on the pump piston at the start of operation and then return to the liquid reservoir through the outflow perforation in the pump cylinder.

[0057] Another possible structural configuration specifies that the pump cylinder has an outflow perforation in its cylinder wall, arranged such that it is passed over by the pump piston as it moves from an unoperated end position to an operated end position. Until this point, liquid can return from the pump chamber to the liquid reservoir. Once the pump piston has passed the outflow perforation, the liquid in the pump chamber is pressure-loaded and thus discharged.

[0058] Although liquid can be forced back from the pump chamber to the liquid reservoir at a defined intermediate position via an inlet valve based on displacement and through the aforementioned outlet channel, the outlet channel is preferred because it allows for the avoidance of negative pressure in the pump chamber during the return stroke. Such negative pressure is desirable because it necessitates a sufficiently strong return spring to overcome it. The use of the additional outlet channel eliminates this need. Therefore, it is particularly advantageous for pump units with an outlet channel to have an inlet valve configured to close based on pressure, opening only when there is overpressure in the pump chamber relative to the liquid reservoir. Such a pressure-based inlet valve allows for liquid intake into the pump chamber almost immediately following the start of the return stroke. Preferred designs for the inlet valve are, in particular, flat valves or valves with a ball valve.

[0059] The pump unit described is preferably made entirely of plastic, particularly only of plastics that can be processed in a common recycling stream. However, the pump unit may also have a smaller share of other plastics or metals, provided that their total share in the mass of the pump unit does not exceed 10%, and preferably does not exceed 5%.

[0060] The liquid dispenser according to the invention has a pump unit according to the invention. Particularly preferred is that such a liquid dispenser has a liquid reservoir made of plastic. The liquid reservoir preferably has an opening into which the pump unit is inserted, and the pump unit is preferably secured in the opening by means of a housing cover.

[0061] The liquid reservoir preferably has a total volume of less than 100 ml, especially less than 50 ml. When ready for sale, the liquid reservoir preferably contains pharmaceutical or cosmetic liquids. Attached Figure Description

[0062] Other advantages and aspects of the invention will become apparent from the claims and the following description of preferred embodiments of the invention, which are explained below with the aid of the accompanying drawings.

[0063] Figure 1A and 1B An uncut illustration shows the liquid dispenser according to the invention and the pump unit for the liquid dispenser.

[0064] Figure 2 A first variant of the pump unit according to the invention is shown in cross-section.

[0065] Figure 3A and 3B It shows the use of Figure 2 , 5 Different variations of the return spring for pump unit 6.

[0066] Figures 4A to 4C The deformation of the return spring of the pump unit according to the present invention during operation is explained.

[0067] Figure 5 , 6 Figures 7 and 8 show the second, third, and fourth variations of the pump unit according to the invention in cross-section. Detailed Implementation

[0068] Figure 1A and 1B A liquid dispenser 100 and a pump unit 10 for the liquid dispenser are shown, the pump unit being coupled to a liquid reservoir 110 to form the liquid dispenser 100. The pump unit 10 has a discharge head 90 having a smear tip 96 with a discharge port 92. Figure 1A and 1B In this state, the protective cap is placed on the pump unit 10.

[0069] Figure 2 The liquid dispenser 100 is shown in cross-section. It can be seen that the pump unit 10 is inserted through an opening in the body of the liquid reservoir 110 and secured by means of a closure 94. Figure 2 The design specifies that the bottle body has such a tapered neck region 114 that a direct radial seal is formed relative to the outer surface of the pump unit 10.

[0070] Pump unit 10 has a pump cylinder 30, which forms a housing and is divided into a cylinder housing 32 and a housing cover 40. The cylinder housing 32 and the housing cover 40 each have outwardly pointing mounting flanges 36 and 42, which are pressed together by means of a closure 94 and pressed against the neck of the bottle.

[0071] The discharge pipe 60 extends into the cylinder housing 32 through a perforation in the housing cover 40. On the outer surface of the cylinder housing 32, a discharge head 90 is connected to the discharge pipe 60, which forms a liquid path to the discharge port 92.

[0072] As per regulations, the discharge head 90 is pressed down to facilitate discharge. Pressing down the discharge head 90 also causes the discharge pipe 60 to be pressed down.

[0073] A return spring 70 is provided inside the pump cylinder 30, and in this embodiment, the corresponding component performs other functions besides the return spring function, as will be explained below. The return spring 70 has an outwardly extending support element 73 at its upper end 72. This support element is designed in the form of a surrounding bearing ring, but it can also be designed differently and, in particular, can have an interruption. The surrounding design of the support element 73 makes it an effective seal between the housing cover 40 and the cylinder housing 32. Furthermore, the support element 73 is placed under stress by the closure 94, thus eliminating concerns about slippage.

[0074] Below the support element 73 is a spring region 80, designed in the form of a cage spring. This means that multiple nodes 82 are provided in the spring region 80, which are interconnected in a mesh-like manner by spring tabs 79. The possible construction of the cage spring is described in detail below, which is configured to provide a restoring force that returns the pump unit 10 to its initial state after manual operation has ended.

[0075] For this purpose, the lower end 74 of the return spring 70 is connected to the discharge pipe 60. This connection is established by providing a surrounding stop surface 61 at the lower end of the discharge pipe 60, which has a slightly conical shape. Correspondingly, a similarly slightly conical stop surface 71 is provided on the inner surface of the return spring 70. The stop surfaces 61 and 71 abut against each other and appear to be hooked together by the aforementioned inclination.

[0076] If the discharge pipe 60 is pressed down by the discharge head 90, the return spring 70, especially its spring region 80, is stretched as a whole and generates a return force that becomes stronger with the increase of displacement. The return spring 70 is already under tensile stress in its unoperated terminal position, thus generating a return force from the outset upon operation, which achieves reset to the terminal position. The return spring 70 has a construction, explained in detail below, designed to achieve small relaxations through a persistently generated state of tensile stress.

[0077] The overall stretching of the return spring 70 is not related to the displacement of the discharge pipe caused by the stretching of a portion of the return spring. More precisely, in the case of bending deformation of a portion of the return spring 70, particularly the node 82 of the return spring, the entire return spring 70 is stretched within the spring region 80 of the cage spring, where at least two, preferably four, paired, open spring tabs 79 are arranged. This point will be explained further below.

[0078] A pump piston 50 is provided at the lower end of the return spring 70 or at the discharge pipe 60. This pump piston has a piston lip 52 that abuts against the cylindrical wall of the cylinder housing 32 at least in stages during operation. In the embodiment, the pump piston 50 is configured as the distal end of the return spring 70, but it can also be configured as a separate component and mechanically connected to the return spring. If the lower end 74 of the return spring 70 is pressed down by means of the discharge pipe 60, the pump piston 50 is also pressed down, and the pump chamber 12 defined by it is isolated and subsequently reduced in size.

[0079] In addition to the larger diameter spring region 32B, the cylinder housing 32 also has a pump chamber region 32A, which matches the diameter of the pump piston 50. In this embodiment, this pump chamber region, together with the pump piston 50, defines the pump chamber 12.

[0080] exist Figure 2 In the design scheme, a groove 32C is provided on the inner side of the pump chamber region 32A. This groove ensures that the pump piston 50 does not yet isolate the pump chamber 12 below the pump piston 50 from the spring region 32B in this region. Therefore, if from... Figure 2 Starting from the unmanipulated terminal position, the pump piston 50 is pressed down, which only causes the pump chamber 12 to be isolated when the lower end of the groove 32C is passed by the pump piston. Only then does the reduction of the pump chamber 12 allow the liquid contained therein to be forced through the groove 32C into the spring region 32B of the cylinder housing 32, from where the liquid can return to the liquid reservoir 110 through the outflow perforation 32D.

[0081] As the pump continues to move, the pressure in the pump chamber 12 then increases, thereby keeping the inlet valve 16 closed at the liquid inlet 14 and opening the outlet valve 20. Currently, the inlet valve 16 is configured as a pressure-dependent flat valve with a limitedly movable valve plate that is pressed downwards by the overpressure in the pump chamber, thereby closing the liquid inlet 14. The outlet valve 20 is formed by a valve face 50A on the inner side of the pump piston 50 and by a valve member 64, which is inserted into the outlet pipe 60 from below while maintaining a net cross-section. The outlet valve 20 opens when the pressure in the pump chamber 12 is sufficient to expand the pump piston 50 to such an extent that it loses contact with the conical valve face 20A of the valve member 64, and thus liquid can flow from the pump chamber 12 into the liquid outlet 18. Discharge ends no later than reaching the manipulated terminal position of the outlet head 90. According to the design, this can be the case when the pump piston 50 abuts against the lower end of the cylinder housing 32, when other stops on the discharge head 90 and discharge pipe 60 abut against the stop surface, or when the inlet valve 16 opens due to displacement at the end of operation.

[0082] Near the end of the operation, the piston lip 52 strikes the lower end of the pump chamber 12, thereby deforming the piston lip 52 and forcibly opening the discharge valve. This is advantageous because it allows the discharge valve 20 to be forcibly opened even when the distributor is in operation, when there is still compressible air in the pump chamber and therefore the discharge valve 20 does not open according to pressure, and thus air can leak out of the pump chamber 12.

[0083] If the force applied to the discharge head 90 is released as the operation ends, the liquid distributor 100 returns to its initial position. The return spring 70, which was under tension as a whole, or its spring section 80, shortens again and pulls the pump piston 50 upward. This causes a negative pressure in the pump chamber 12 due to the now-closed discharge valve 20, the opening of the inlet valve 16, and the intake of liquid from the liquid reservoir 110. At the same time, the discharge pipe 60 and thus the discharge head 90 are also pushed upward.

[0084] Figure 3A and 3B Several possible cage springs that can be used as return springs 70 are shown. All return springs 70 share the common feature of having a flange-like support element 73 at their upper end 72, by which the upper end of the return spring 70 is fixed to the pump cylinder 30, and an integrally molded pump piston 50 is provided at the lower end 74 of the return spring. The different return springs differ in their respective spring regions 80. Unlike these designs, cage springs that are not integrally formed with the pump piston can also be used.

[0085] What all the spring regions have in common is that they are constructed in the style of a cage spring and have multiple perforations that cause the spring tabs 79 to cut freely. These spring tabs 79 are connected together in multiples, usually in pairs or fours, to the node 82 of the cage spring. The spring tabs 79 also extend at least in the circumferential direction. If the return spring is stretched as a whole, this does not result in the different sections of the spring being stretched by the same distance or to the same degree. Instead, bending deformation occurs mainly in the area of ​​the node 82, but also partly in the area of ​​the spring tabs 79 themselves.

[0086] In accordance with Figure 2 In the design of the dispenser, but also as specified in the following design, the liquid taken from the liquid reservoir 110 is replaced by incoming air. This air flows through the perforation 44 on the outer side of the discharge pipe 60, as specified. However, in Figure 2 In the unoperated position, the path is blocked by the sealing lip 84 on the inner side of the return spring 70. Ventilation is only opened during operation, and even then, it is delayed. This is done by the step 62 of the discharge pipe 60 passing beside the sealing lip 84 as operation proceeds, causing the ventilation path to open into the pump cylinder 30, through which compensated air can reach the liquid reservoir via the discharge perforation 32D.

[0087] Figure 3A The first design has a total of 16 perforations 78, 28 spring tabs 79, and 16 node parts 82. The perforations 78 are elliptical in shape, so that the spring tabs 79 have an oblique orientation about the longitudinal direction 2 when the spring is in an unstretched state.

[0088] Figure 3A The second design also features a total of 16 perforations 78, 28 spring tabs 79, and 16 node members 82. However, the perforations 78 are not elliptical in shape, but are larger in the side regions than in the center. This provides strongly rounded side regions that do not cause a notching effect when the return spring 70 deforms and thus effectively retain the stress already present in the unmanipulated end position.

[0089] exist Figure 3A The third design also includes a total of 16 perforations 78, 28 spring tabs 79, and 16 node members 82. However, here, the perforations 78 are again shaped differently. In their relaxed state, they are each formed by two circular partial perforations connected by a slit, in which the spring tabs 79 directly abut against each other above and below the perforations 78. The aforementioned circular partial perforations also result in the absence of a cut-out effect.

[0090] exist Figure 3A The fourth design scheme includes 16 perforations 78, 28 spring tabs 79, and 16 node components 82. However, here, the perforations are designed as narrow slits, and the opposing edges of the narrow slits do not abut against each other in the relaxed state shown.

[0091] exist Figure 3B In the first design, 32 perforations 78, 56 spring tabs 79, and 32 node members 82 are provided. The key feature here is a total of three encircling annular segments, which respectively form eight node members 82 and eight spring tabs 79. These annular segments are interconnected and connected to the lower and upper return spring regions of the spring region 80 via eight additional spring tabs 79. Four additional node members 82 are provided on the lower and upper return spring regions of the spring region, respectively.

[0092] Figure 3B The second design is similar to the first. However, because the annular segments are designed differently from the first design, they do not deform or hardly deform when the return spring 70 is stretched, and therefore do not store the associated energy share even in the deformed state. However, in Figure 3B In the case of the design scheme, the annular segments are still advantageous because they represent the stabilizing ring 86, which is otherwise stabilized by the stabilizing ring spring region 80 and avoids the non-uniform deformation of the return spring 70 in the circumferential direction.

[0093] Figure 3B The third design scheme is in principle the same as Figure 3B The first design is very similar. The difference here is that instead of three annular segments, four annular segments are provided, resulting in a total of 40 perforations 78, 72 spring tabs 79, and 40 node pieces 82.

[0094] Figure 3B The fourth design scheme is similar to the second design scheme and is a variation of the aforementioned variant scheme. However, the annular segment is not subjected to bending deformation during spring tension due to the upward and downward connection itself. Therefore, the annular segment is also used as a stabilizing ring 86 here.

[0095] With the help of Figure 4A and 4B This explains the deformation of a spring. The diagram illustrates the principle of deformation; however, it does not directly represent the actual situation in the installed state, because the installed state differs from the actual situation. Figure 4A Differences always exist because they have already been transformed.

[0096] despite this, Figure 4A and4B This indicates that the elongation of the return spring 70 and therefore the elongation of the spring region 80, which is thus constructed as a cage spring, is accompanied by the following: Figure 4A and 4B In normal orientation, the essentially horizontal spring tab is deformed by the tension of the return spring 70, with this deformation mainly occurring in the transition region between the connected node 82 and the corresponding spring tab 79. Figure 4B The deformation state is shown, with the main deformation region indicated by shading, where more than 80% of the energy applied by tension is stored. This main deformation region occurs at node 82, where the deformation is primarily bending, i.e., it includes both tensile and compressive stresses.

[0097] The tendency to relax under such stress has been proven to be small. Even during long supply and storage periods (where the return spring 70 is under sustained stress), most of the original return tendency remains unchanged and reliably reaches the unmanipulated end position after the first manual operation.

[0098] exist Figures 4A to 4C The perforation 78 in the return spring 70 has a bone shape in the initial state. This is achieved by relatively large rounding at the respective ends, which simultaneously prevents notch effects and provides an ideal structure for withstanding tensile stress.

[0099] Figure 4C The spring section is shown. Figure 4B The cross-section is shown at the height of the marked cutting plane. Here it can be seen that the wall cross-section tapers inwards, with the inclined surface extending beyond the radial relative adjustment. This design has been shown to contribute to the stability of the cage spring.

[0100] Figure 5 , 6 Figures 7 and 8 show alternatives relating to the distributor or its pump unit 10. Unless otherwise explained, the remaining features of the corresponding pump unit 10 are the same as those shown in Figures 7 and 8. Figure 2 The pump unit 10 has the same features as described above.

[0101] exist Figure 5 In the design scheme, instead of the inlet valve 16 which is constructed as a flat plate valve, a ball valve is provided, that is, a valve with a deflectable ball, which isolates the liquid inlet 14 from the pump chamber 12 in the closed position.

[0102] The second difference is that, in this design, the piston lip 52 does not contact the wall of the pump cylinder 30 at all in the unoperated terminal position. During operation, the piston lip 52 is guided into the pump chamber 12 by an inlet ramp and terminates circumferentially with the pump cylinder 30. Liquid that previously leaked through the gap between the piston lip 52 and the pump cylinder 30 returns to the liquid reservoir 110 through the outflow perforation 32D.

[0103] Once pump chamber 12 is isolated and the ball valve is closed, the pressure in the pump chamber increases and discharge valve 20 opens. After discharge, the valve returns to its original position under the action of return spring 70 and its cage spring. The ball valve can open immediately, thus preventing the high negative pressure that return spring 70 must overcome from being generated in pump chamber 12.

[0104] exist Figure 6 In the design, an outflow perforation 32E is provided in the wall of the pump cylinder 30 at the height of the pump chamber 12. The pump chamber 12 is isolated and the pressure rises and flows into the liquid output section only after the piston lip 52 has passed this outflow perforation 32E.

[0105] In this design, the inlet valve 16 is configured as a slit valve, which opens when there is negative pressure in the pump chamber 12.

[0106] exist Figure 7 In the design, a closing protrusion 13 is provided on the valve component 64. After the empty stroke, the closing protrusion 13 enters the metering channel of the inlet valve 16 and thus isolates the pump chamber 12, so that the continued movement puts the liquid inside under pressure and causes the liquid to be discharged. During the return stroke, a negative pressure is first formed in the pump chamber 12. When the closing protrusion 13 has left the metering channel of the inlet valve 16, the liquid can be drawn in under the action of the previously formed negative pressure.

Claims

1. A pump unit (10) for a liquid dispenser (100) made of plastic, having the following characteristics: a. The pump unit (10) has a pump cylinder (30) and a pump piston (50), the pump piston being movable relative to the pump cylinder (30) between an unoperated end position and an operated end position, wherein the pump chamber (12) surrounded by the pump cylinder (30) and the pump piston (50) has its maximum volume in the unoperated end position and its minimum volume in the operated end position, and b. The pump unit (10) has an inlet valve (16) at the liquid inlet (14) and a discharge valve (20) at the liquid outlet (18), and c. The pump unit (10) has a return spring (70), and the pump piston (50) is loaded with a force in the direction of the unoperated end position by means of the return spring. Its features are as follows Other features: d. The return spring (70) is constructed as a tension spring and arranged such that the cylinder-side end (72) and the piston-side end (74) of the return spring (70) are spaced apart longitudinally when the pump chamber (12) contracts, thereby creating or reinforcing tension in the return spring (70). e. The return spring (70) is at least sectionally constructed as a cage spring, the cage spring having a wall (77) having a basic cylindrical or conical shape, and f. The wall (77) of the cage spring has a structure consisting of perforations (78), the structure having nodes (82) and spring tabs (79) connecting the nodes (82).

2. The pump unit (10) according to claim 1 has the following additional features: a. The cage spring has at least four nodes (82), from which at least three spring tabs (79) extend to other nodes or to the area (72, 74) of the return spring (70) adjacent to the cage spring. Preferably, it has the following additional features: b. The cage spring has at least eight nodes (82), from which at least three spring tabs (79) extend to other nodes or to the area (72, 74) of the return spring (70) adjacent to the cage spring.

3. The pump unit (10) according to claim 1 or 2, has the following additional features: a. The cage spring has spring tabs (79) integrally mounted on a common node (82) and the spring tabs are opened during the separation of the ends (72, 74) of the return spring (70) and thereby cause bending deformation in the node (82).

4. The pump unit (10) according to claim 3 has the following additional features: a. With the return spring (70) under tension, when the pump piston (50) is positioned in the operated end position, at least 50% of the spring energy stored in the return spring (70) is stored in the bending deformation of the node (82) and the spring tab (79). Preferably, it has the following additional features: b. When the return spring (70) is in a tensioned state, at least 80% of the spring energy stored in the return spring (70) is stored in the bending deformation of the node (82) and the spring tab (79).

5. The pump unit (10) according to any one of the preceding claims has one of the following additional features: a. The cage spring has between 8 and 200 perforations (78), preferably between 12 and 100 perforations (78), and / or b. The cage spring is made of polyolefin, preferably polyethylene.

6. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The cage spring has a through hole (78), which is defined by four spring tabs (79), namely two upper spring tabs and two lower spring tabs (79), and b. Two spring contacts (79) are formed by one lower spring contact and one upper spring contact (79), and these two spring contacts are connected on the side of the through hole (78) by a common node (82), and c. The upper spring tab and the lower spring tab (79) form the following spring tab (79), which are connected to each other in the center position about the through hole by other node members (82).

7. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The cage spring has a surrounding structure consisting of node members (82) and connected spring tabs (79), wherein the spring tabs (79) are connected to the node members (82) at both ends and at least some of the node members (82) respectively carry at least two pairs of spring tabs (79). Preferably, it has at least one of the following additional features: b. Multiple nodes (82) distributed along the periphery are interconnected by a surrounding stabilizing ring (86) preferably integrally connected to the nodes (82), and / or c. At least one node bearing the two pairs of spring tabs (79) has a cross-section in a plane orthogonal to the longitudinal direction, the cross-section having a shape that gradually tapers or expands along the central axis of the return spring.

8. The pump unit (10) according to any one of the preceding claims has at least one of the following additional features: a. The cage spring has perforations (78) that form a net spacing along the longitudinal direction (2) in the lateral region, the net spacing being greater than the center net spacing along the longitudinal direction, and / or b. Two spring tabs (79) integrally connected to the node (82) are connected by a rounded transition portion at the node (82), the transition portion preferably having a minimum rounded radius greater than 0.5 mm, particularly having a rounded radius greater than 1.0 mm, and / or c. When the pump cylinder (30) and pump piston (50) are arranged in the operated end position, the spring tabs (79) form an angle at a common node (82) that is between 5° and 50° larger than the angle formed by the spring tabs (79) when the pump cylinder (30) and pump piston (50) are arranged in the unoperated end position.

9. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The return spring (70) has a piston geometry at its lower end integrally molded onto the spring region, with a surrounding piston lip (52), and b. The piston lip (52) abuts against the cylindrical pump cylinder (30) on its inner side. Preferably, it has one of the following additional features: c. The return spring (70) has a valve face (20A) of the discharge valve (20), and when the discharge valve (20) is closed, the valve section of the valve body abuts against the valve face, and / or d. The cylindrical pump cylinder (30) has two sections with different diameters, wherein the piston lip abuts against the section with the smaller diameter on its inner side.

10. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The pump unit (10) has a discharge pipe (60) that extends into the internal region of the return spring (70), and b. The discharge pipe (60) and the return spring (70) have mutually acting stop surfaces (61, 71), by means of which the return spring (70) can be stretched by means of the discharge pipe (60). Preferably, it has the following additional features: c. The stop surfaces (61, 71) have a tapered shape.

11. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The pump unit (10) has a discharge pipe (60) inserted into a return spring (70), and b. The pump unit (10) has a valve member (64) that is inserted into the discharge pipe (60). Preferably, it has at least one of the following additional features: c. The inserted valve member (64) together with the return spring (70) forms a discharge valve (20), and / or d. The inserted valve component (64) together with the bottom of the pump cylinder forms an inlet valve (16).

12. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The return spring (70) has at least one outwardly extending support element (73), preferably in the form of a bearing ring, at one end (72) to form a spring seat on the cylinder side, and b. The return spring (70) is fixed to the pump cylinder (30) in the longitudinal direction (2) by means of a support element (73), wherein abutment surfaces (73A, 33) are provided on the support element (73) and the pump cylinder (30) for this purpose. Preferably, it has at least one of the following additional features: c. The abutment surface (73A) on the support element (73) and / or the abutment surface (33) on the pump cylinder (30) are orthogonal to the operating direction when forming a stepped structure, and / or d. The abutment surface (73A) on the support element (73) and / or the abutment surface (33) on the pump cylinder (30) are provided with chamfers, which resist slippage.

13. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The pump unit (10) has a cylinder housing (32) and a housing cover (40) to form a pump cylinder (30). Preferably, it has one of the following additional features: b. The housing cover (40) and the cylinder housing (32) each have outwardly extending mounting flanges (42, 36), wherein the two mounting flanges (42, 36) directly abut against each other, and / or c. The housing cover (40) is provided with a perforation (44), through which an operating push rod (60) preferably in the form of a discharge pipe (60) extends.

14. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The inlet valve (16) is configured to close according to displacement, wherein the inlet valve is closed only after a free stroke when the pump piston (50) moves from the unoperated end position toward the operated end position, or b. The pump unit has an outflow perforation (32D) through which liquid can flow from the pump chamber (12) back to the liquid reservoir (110), and the outflow perforation is closed only after a no-load stroke when the pump piston (50) moves from an unoperated end position to an operated end position. Preferably, it has additional features: c. The idle stroke is at least 5%, preferably at least 10%, of the distance between the operated and unoperated end positions of the pump piston (50).

15. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The pump cylinder (30) and the pump piston (50) are coordinated such that they do not circumferentially seal against each other in the unoperated end position, and only circumferentially seal against each other after the empty stroke has passed during the movement of the pump piston (50) toward the operated end position. Preferably, it has at least one of the following additional features: b. An outflow perforation (32D) is provided in the wall of the pump cylinder (30), through which liquid flowing from the pump chamber (12) returns to the liquid reservoir (110) before reaching the contact point of the surrounding seal, and / or c. The idle stroke is at least 5%, preferably at least 10%, of the distance between the actuated and unactuated end positions of the pump piston (50), and / or d. The inlet valve (16) is configured to close under pressure, and to open relative to the liquid reservoir (110) in the presence of negative pressure in the pump chamber (12), wherein the inlet valve (16) is preferably implemented either as a flat plate valve or as a valve with a ball, and / or e. In the unmanipulated terminal position, an annular gap is left between the inner wall of the pump cylinder (30) and the pump piston (50), or f. The pump piston (50) in the unoperated terminal position abuts against the inner wall of the pump cylinder (30) through a partial section of its periphery and is separated from the inner wall of the pump cylinder (30) in another partial section of its periphery, in the case of forming an outflow channel (32C).

16. The pump unit (10) according to any one of the preceding claims has the following additional features: a. The pump cylinder (30) has an outflow perforation (32E) in the cylinder wall, wherein the outflow perforation (32E) is arranged such that it is passed over by the pump piston when the pump piston is transferred from an unoperated end position to an operated end position.

17. A liquid dispenser (100) for dispensing pharmaceutical or cosmetic liquids, having the following features: a. The liquid dispenser (100) has a liquid reservoir (110), and b. The liquid dispenser (100) has at least one outlet (92), and c. The liquid dispenser (100) has a pump unit (10) by means of which liquid can be pumped from the liquid reservoir (110) to the outlet (92). Its features The following additional features: d. The pump unit (10) is configured according to any one of the preceding claims, Preferably, it has at least one of the following additional features: e. The liquid reservoir (110) has a volume of less than 100 ml, preferably less than 50 ml, and / or f. The liquid reservoir (110) is filled with pharmaceutical or cosmetic liquids, and / or g. The liquid distributor (100) is configured as a jet distributor or a distributor or droplet distributor for outputting an unatomized liquid jet.

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