Pump dispenser

Abstract

The invention relates to a pump dispenser (11) for the metered removal of a liquid from a container on which the pump dispenser (11) can be placed, having a housing (13) which can be held on the container by a cap (21) and in which a metering chamber (15) is formed, further having a pump head (29) with a dispenser opening (27), said pump head being movable in the axial direction. The pump head (29) is connected for conjoint rotation to a control element (41) having a first external thread (53). A control sleeve (43) having a first internal thread (65) is arranged between a closure ring (35) and the control element (41). By way of a telescopic retraction and extension of the control element (41) out of the control sleeve (43), a total length of control element (41) and control sleeve (43) is defined in dependence on the angle of rotation.

Description

[0001] Pump dispenser

[0002] Field of the invention

[0003] The invention relates to a pump dispenser according to the preamble of claim 1 and a pump system according to claim 24.

[0004] State of the art

[0005] Pump dispensers are used to dispense a liquid, which may have a higher viscosity (creams or gels), from a storage container by pressing down on a dispenser head. Some versions have a dispenser extension attached to the dispenser head and therefore move with it.

[0006] Generally, a pumping system includes a container for the product and a pump dispenser attached to an opening of the container.

[0007] A pump head can be operated in a pumping stroke relative to the housing to vary the volume of the metering chamber and to dispense through an outlet channel, often via an outlet valve. After the piston is depressed, the piston is raised by the inlet valve, usually driven by a return spring, to refill the metering chamber.

[0008] Although alternatives exist, the piston is often directly or indirectly connected to the pump head. Since metal has excellent memory properties, the spring is often made of stainless steel. However, to improve recyclability, it is desirable to manufacture all components from the same material, preferably polypropylene. However, the memory properties of this material are very low.

[0009] To return the pump head to its uppermost position, the force of the spring must at least overcome the internal frictional resistance of the components plus the fluid resistance. Since these resistances can vary, the spring has a so-called preload in the upper position.

[0010] For transport and safety reasons, the pump system is often sold commercially with the dispenser head in the lower position. In this position, the spring is compressed and locked until the end of its stroke, often with a threaded lock. The force of the spring in this position is even greater than the preload in the upper position. The end user can unlock this by rotating the pump head, after which the pump head returns to its original position.

[0011] It is difficult to guarantee the force of a plastic spring under pre-tension in the upper position over a longer period of time, but it is impossible to guarantee it under full tension in the transport position with polypropylene according to the state of the art.

[0012] Object of the invention

[0013] The object of the invention is therefore to create a pump dispenser in which the plastic spring is not only relieved in the operating position, but also when the pump head is retracted, so that the plastic spring is only compressed or stressed during use of the pump dispenser and nevertheless requires as little space as possible during storage and transport.

[0014] Description

[0015] The stated problem is solved in a pump dispenser by the features stated in the characterizing portion of patent claim 1. Further developments and / or advantageous embodiments are the subject of the dependent patent claims.

[0016] The invention is preferably characterized in that the pump head is connected in a rotationally fixed manner to a control element which has a first external thread and is in the shape of a cylinder with a casing, and in that a control sleeve with a first internal thread is arranged between the locking ring and the control element, wherein the control element is rotatably and centrally mounted within the control sleeve and the first internal and external threads interact to define a total length of the control element and control sleeve as a function of the angle of rotation by a telescopic retraction and extension of the control element from the control sleeve, which total length serves to compress the plastic spring in accordance with the total length of the control element and control sleeve. The stated object is thereby achieved in that the plastic spring is not permanently compressed and loaded in the transport position of the pump head, but is permanently relaxed and unloaded.The plastic spring is only compressed for the pumping process when the pump dispenser is used. This significantly extends the service life of the plastic spring, as it is only stressed when the pump dispenser is in use. In a particularly preferred embodiment of the invention, the control element is pressed from below onto the locking ring by the plastic spring, and there is a positive connection between the control element and the locking ring. This connection is intended to ensure that the control element extends out of the locking ring when the pump head is in a specific twisted position, thereby pushing the pump head into the second, upper position. The pump head can thus be turned into the active position, in which position liquid can be pumped out of the container in a known manner by the user pressing down and the pump head then springing back.By extending the pump head after turning it counterclockwise, the user is shown that he has operated the pump dispenser correctly and has correctly moved the pump head from the transport position to the pumping position.

[0017] In another particularly preferred embodiment of the invention, the control element has a first shoulder formed in the circumferential direction, with a first control part located above the first shoulder and a second control part located below the first shoulder. The first shoulder allows the control element to have an enlarged diameter only in the region of the first control part, which is necessary to ensure sufficient space for the pump head to be connected to the control element in a rotationally fixed manner. The first shoulder can also rest on the second shoulder of the control sleeve in the transport position for stabilization in this position.

[0018] It is preferred if the control sleeve has a first sleeve part and a second sleeve part, which sleeve parts are connected to each other by a second shoulder. This creates a shoulder for the piston to strike when the pump head is pressed downward.

[0019] It is advantageous if the second control part protrudes into the second sleeve part for axial guidance of the control element and is axially displaceable within it. This clearly defines the fluid path from the dosing chamber to the dispensing opening, and simultaneously holds and guides the control element in every axial position within the closure ring and the second sleeve part.

[0020] In the above embodiment, it is advantageous if a seal is arranged at the lower end of the second control part, which seals the interior of the second sleeve part from the interior of the first sleeve part. The seal enables sealing with respect to the first sleeve part and axial displacement of the lower end of the second control part within the second sleeve part.

[0021] In a further preferred embodiment of the invention, an apron is formed on the locking ring for axial and rotationally fixed guidance of the control sleeve. On the inside of the apron, first axially oriented guide elements are provided, which interact with second guide elements formed on the first sleeve part. These guide elements act as a linear guide slot for the first sleeve part, thereby transforming the rotational movement of the control element into a linear movement of the control sleeve. The guide elements also act as an anti-twist device between the control sleeve and the locking ring. Alternatively, such an anti-twist device can also act between the control sleeve and the housing by means of corresponding guide elements.

[0022] In a preferred embodiment of the invention, the positive locking is achieved by having a circular cross-section with a flattened portion, and by having the through-opening of the locking ring with a corresponding negative shape of the cross-section of the control element. When the cross-section and the negative shape are aligned at a specific angle of rotation of the pump head, the control element, preloaded by the spring, can be pushed upwards out of the locking ring. This provides the user with clear feedback that the pump function has been activated.

[0023] For convenience, the lower end of the flattened portion is defined by a third shoulder. This holds the control element and control sleeve securely in the upper position of the pump head, as the first sleeve section and the third shoulder are pressed against the underside of the locking ring.

[0024] In a further preferred embodiment of the invention, the positive locking is achieved by the control element having a first groove on its casing, in which a lug formed in the through-opening is guided. Here, the positive locking is achieved when the lug is aligned with the groove at a specific angle of rotation.

[0025] In a further preferred embodiment of the invention, the positive connection is achieved by forming a second external thread at the upper end of the casing of the control element, which interacts with a second internal thread formed at the edge of the through-opening. This design has the advantage that the height of the pump head changes as it is rotated before the first control part is pressed out of the locking ring.

[0026] It is advantageous if a rib extending in the axial direction is formed on the casing, which can connect the first external thread to the second external thread. Preferably, a second groove is provided on the locking ring, in which the rib is guided. As a result, the first control part, in the embodiment with the second external and internal thread, is pressed axially upward in a rotationally fixed and stable manner.

[0027] Conveniently, the plastic spring is connected to the control sleeve by a spring retainer. This allows the spring to reliably press against the lower end of the second sleeve part. It would also be conceivable for a flange to be formed on the second sleeve part instead of the spring retainer.

[0028] In a particularly preferred embodiment of the invention, the piston on the control sleeve is displaceable between a first and a second position, wherein in the first position it strikes the spring holder when the pump head is pushed upwards and in the second position it strikes the second shoulder when the pump head is pushed downwards. As a result, an outlet valve can be easily implemented in combination with the liquid opening described in the next paragraph, because the upper and lower stops for the piston are already present. It is preferred if at least one liquid opening is provided on the control sleeve, which acts together with the piston as an outlet valve. When the pump head is pushed down by the piston, the liquid opening is opened and when the pump head is pushed upwards by the piston, the liquid opening is closed.As a result, the liquid opening is always reliably open when the pump head is pressed downwards and liquid is pressed from the dosing chamber into the channel formed by the second sleeve part, the second control part and the first control part.

[0029] It is particularly preferred if the pump head is pressed against the locking ring by the spring when it is turned and is locked in the direction of rotation when the positive locking takes effect and is pushed axially upwards by the spring. This allows the pump head to be transferred from its transport position into the pumping position by simply turning it. It is particularly preferred if, in a transport position of the pump head, it is retracted into the locking ring and, in the transport position, the pump head assumes a rotation angle of 0 degrees relative to the locking ring and the control element is completely retracted into the control sleeve in the transport position, as a result of which the plastic spring is relaxed. This means that the plastic spring is relaxed and therefore protected throughout the entire period of storage in a business premises and during transport.The service life of the spring can therefore be significantly increased and the spring will not break or lose tension, even if the container is refilled several times.

[0030] In a particularly preferred embodiment of the invention, the control element can be unscrewed from the control sleeve when the pump head is rotated counterclockwise, whereby the plastic spring is compressed more strongly the further the pump head is rotated. This allows the plastic spring to be kept virtually tension-free, even when the pump head is in the space-saving and securely closed transport position. Only the telescopic extension, formed by the control element and the control sleeve, compresses the plastic spring when needed, allowing the pump head to be pushed upwards out of the locking ring so that it reaches the pumping position.

[0031] It is advantageous if the pump head's angle of rotation has a specific value, specifically 270 degrees, when the control element is fully extended axially from the control sleeve and the plastic spring is maximally compressed. The thread pitch of the first internal and external threads is adapted to the angle of rotation of 270 degrees such that the control element is fully extended from the control sleeve at this angle of rotation. Further counterclockwise rotation is prevented by the positive engagement between the control element and the locking ring.

[0032] It is also advantageous if the pump head's angle of rotation has a specific value, particularly a value of 270 degrees, when the positive locking between the locking ring and the control element engages. This ensures that the angle of rotation at which the control element is fully extended from the control sleeve and at which the positive locking engages prevents the screw connection between the control element and the control sleeve from being overtightened.

[0033] In another particularly preferred embodiment, the positive engagement between the locking ring and the control element only occurs when the control element is fully extended axially from the control sleeve. Thus, maximum spring compression is achieved when the control element extends from the locking ring.

[0034] It is advantageous to provide a notch on the first internal thread into which a lower end of the first external thread can be locked. This locks the control element or pump head in the opposite direction of rotation to the opening direction. This prevents application errors and makes the pump dispenser more user-friendly.

[0035] A further aspect of the invention relates to a pump system comprising a container and a pump dispenser attached to the container, as described above. Further advantages and features will become apparent from the following description of an exemplary embodiment of the invention with reference to the schematic representations. These are not to scale:

[0036] Figure 1: a sectional view of a pump dispenser in the transport position;

[0037] Figure 2: a sectional view of the pump dispenser in which the pump head is rotated by 60 degrees and a control element is partially extended axially from a control sleeve;

[0038] Figure 3: a sectional view of the pump dispenser with the pump head rotated by 270 degrees and the control element fully extended axially from the control sleeve;

[0039] Figure 4: a sectional view of the pump dispenser in which the pump head is rotated by 270 degrees and the control element is partially extended upwards from a locking ring;

[0040] Figure 5: a sectional view of the pump dispenser in which the control element is fully extended axially upwards from a locking ring;

[0041] Figure 6: a sectional view of the pump dispenser in which the pump head has completed part of the pump stroke downwards;

[0042] Figure 7: a sectional view of the pump dispenser, with the pump head having completed the entire downward pump stroke; Figure 8: a sectional view of the pump dispenser, with the pump head having completed the entire upward pump stroke;

[0043] Figure 9: an isometric sectional view of the control unit of the pump dispenser, in which the control element is completely accommodated in the control sleeve in the transport position;

[0044] Figure 10: an isometric sectional view in which the control element is fully extended axially from the control sleeve;

[0045] Figure 11: an isometric sectional view in which the control element is fully extended axially from the control sleeve and the control element is fully extended axially from the locking ring, whereby the pump head is activated;

[0046] Figure 12: an isometric sectional view of the pump transmitter, in which the

[0047] The control element is fully extended axially upwards from a locking ring and the pump dispenser is ready for use;

[0048] Figure 13: an isometric sectional view of the control unit in a first embodiment

[0049] Figure 14: an isometric sectional view of the control unit in a second embodiment;

[0050] Figure 15: an isometric sectional view of the control unit in a third embodiment;

[0051] Figure 16: an isometric sectional view of the control unit in a fourth embodiment, in which the control element is extended from the locking ring;

[0052] Figure 17: an isometric sectional view of the control unit in the fourth

[0053] Embodiment in which the control element is retracted into the locking ring;

[0054] Figure 18: an isometric view of the control sleeve with a notch on a

[0055] internal thread and

[0056] Figure 19 is an isometric view of the control sleeve and a control part interacting with the control sleeve. Figures 1 to 8 and 12 show a pump dispenser, which is designated overall by reference numeral 11.

[0057] A housing 13, in which a dosing chamber 15 of variable volume is formed, forms the component of the pump transmitter 11, on which most of the other components are arranged. The housing 13 preferably has the shape of a rotating cylinder with an open end at the top and a base 17. At the upper end, on the outside of the housing 13, a flange 19 is provided, to which a cap 21 is held. The cap 21 is rotatable relative to the housing 13 and can be screwed onto a container 12 (indicated in Figure 1) in the manner of a union nut with an internal thread.

[0058] At the base 17, a suction tube 23 is connected to the housing 13 in a fluid-permeable manner. A liquid, such as liquid soap or cream, can be sucked into the dosing chamber 15 through the suction tube 23. An inlet valve in the form of a plastic ball 25 is located at the entrance to the housing 13. If a negative pressure prevails in the dosing chamber 15, the inlet valve opens, and liquid is sucked into the dosing chamber 15. If an overpressure prevails in the dosing chamber 15, the inlet valve closes, and the liquid is pumped from the dosing chamber 15 into a dispensing opening 27 of a pump head 29.

[0059] The pump head 29 is movable up and down relative to the housing 13 along the longitudinal axis 31 of the dispenser 11 to execute a pumping stroke between a first lower and a second upper position. The pump head 29 is also rotatable about the longitudinal axis 31 relative to the housing 13. The pump head 29 has a pressure plate 33 with which the pump head 29 can be pressed downwards. The pump head 29 penetrates a locking ring 35 which closes the open end of the housing 13. A plastic spring 37 indirectly pushes a piston 39 upwards after a user has pressed the pump head 29 downwards to deliver liquid. The plastic spring 37 therefore resets the pump head 29 and the piston 39. The piston 39 is movable in a liquid-tight manner on the inner wall of the housing 13 to deliver the liquid.

[0060] The pump head 29 is connected in a rotationally fixed manner to a control element 41. The control element 41 is centrally and rotatably mounted within a control sleeve 43. The control element 41 is essentially in the shape of a cylinder with a casing 45. The control element 41 has a first shoulder 47 formed in the circumferential direction. Above the first shoulder 47 is a first control part 49, and below the first shoulder 47 is a second control part 51 (Figures 3 and 4). Due to the first shoulder 47, the diameter of the second control part 51 is smaller than the diameter of the first control part 49. Above the shoulder 47, a first external thread 53 is formed on the casing 45 of the first control part 49, which is shown in Figures 9 to 16. The first external thread 53 ends in the lower region of the first control part 49.

[0061] The locking ring 35 has a downwardly extending skirt 55. The control sleeve 43 is arranged between the skirt 55 and the control element 41. The control sleeve 43 is also essentially cylindrical in shape and has a second shoulder 57 formed in the circumferential direction. A first sleeve part 59 is located above the second shoulder 57, and a second sleeve part 61 is located below the second shoulder 57. The second sleeve part 61 is closed at the lower end. A spring holder 63, which is plugged onto the lower end of the second sleeve part 61, forms a shoulder for the plastic spring 37, thereby connecting it to the control sleeve 43. The piston 39 can slide up or down on the outside of the second sleeve part 61 between the spring holder 63 and the second shoulder 57, depending on the movement of the pump head 29.The distance between the second shoulder 57 and the spring holder 63 is accordingly higher than the height of the piston 39. A fluid opening 64 is provided on the second sleeve part 61, which, together with the displaceable piston 39, forms an outlet valve.

[0062] On the inside of the first sleeve part 59, a first internal thread 65 is formed, which interacts with the first external thread 53. This allows the control element 41 to be telescopically extended from the control sleeve 43 upon rotation of the pump head 29. The total length of the control sleeve 43 and the control element 41 is therefore defined by the angle of rotation. It is preferred that the control element 41 is fully extended from the control sleeve 43 when the angle of rotation from the transport position of the pump head 29 is 270 degrees.

[0063] The second control part 51 protrudes into the second sleeve part 61 for axial guidance of the control element and is axially displaceable therein. A seal 67 is provided at the lower end of the second control part 51, sealing the interior of the second sleeve part 61 from the first sleeve part 59, even when the second control part 51 is fully extended from the second sleeve part 61. In order for the pump head 29 to extend axially out of the locking ring 35 after the control element 41 has been fully extended from the control sleeve 43, a positive connection is required between the first control part 49 and the locking ring 35. Four embodiments of the positive connection are described below:

[0064] In the first embodiment according to Figure 13, the first control part 49 has a first groove 69 on its casing, in which a nose 73 formed in the through-opening 71 of the locking ring 35 is guided. The first groove 69 ends on its lower side in a step (not shown in the figures) against which the nose 73 abuts. This defines the highest point of the pump head 29, and the spring pressure cannot push the pump head 29 further upward. Additionally, in this upper position of the pump head 29, the upper end of the first sleeve part 59 and the first internal thread 65 abuts the locking ring 35.

[0065] In the second embodiment according to Figure 14, the first control part 49 has a circular cross-section, on which a flattened portion 75 is formed. The flattened portion 75 is rectangular with vertical long sides and horizontal wide sides. At the lower end of the flattened portion 75, a third shoulder 77 (Figure 10) is formed, which abuts the locking ring 35 in the upper position. The through-opening 71 of the locking ring 35 has a corresponding negative shape of the cross-section of the first control part 49.

[0066] In the third embodiment according to Figure 15, a second external thread 79 is formed at the upper end of the casing of the first control part 49. The second external thread 79 interacts with a second internal thread 81 formed at the edge of the through-opening 71. If the second external thread 79 is unscrewed from the second internal thread 81, the spring 37 presses the control element 41 and the control sleeve 43 axially upward until the upper end of the first sleeve part 59 and the first external thread 53 abuts the locking ring 35. This embodiment has the advantage that a change in height is indicated to the user during rotation of the pump head 29 from the transport position, thereby indicating "correct" operation. Given the current products on the market, this type of operation represents a more intuitive unlocking method.

[0067] In the fourth embodiment according to Figures 16 and 17, the third embodiment is expanded by the feature of a rib 83 extending in the axial direction. The rib 83 connects the first external thread 53 to the second external thread 79. A second groove 85 is provided on the locking ring 35, in which the rib 83 is guided. When extended into the second position, the rib 83 is guided in the second groove 85 until the upper end of the first sleeve part 59 and the first external thread 53 abuts the locking ring.

[0068] As schematically illustrated in Figures 18 and 19, in all four embodiments, it can be provided that a reversal of the rotational movement of the control element 41 relative to the control sleeve 43 is prevented, for example by providing a notch 93 on the first internal thread 65. When the plastic spring 37 has reached its full compression due to the rotation of the control element 41, the lower end 95 of the first external thread 53 engages in the notch 93, whereby the control element 41 cannot be rotated back or can only be rotated back with a resistance greater than that of the unlocked control element 41. This reliably prevents application errors when operating the pump dispenser 11.

[0069] In Figures 1 to 8, the function of the pump dispenser 11 is shown step by step using embodiment 2:

[0070] In Figure 1, the pump dispenser 11 or the pump head 29 is in the transport position and is fully retracted into the locking ring 35 or into the housing 13. In this position, the control element 41 and the control sleeve 43 are pushed together to their maximum height and together have the height of the control sleeve 43. This has the great advantage that in this compressed position, the plastic spring 37 is not compressed or only slightly compressed. Even if the pump dispenser 11 remains in the closed transport position for a long time, the spring 37 is not stressed or damaged.

[0071] In Figure 2, the pump head 29, together with the control element 41, has been rotated 60 degrees counterclockwise. Since the user associates counterclockwise rotation with unscrewing, this direction of rotation is sensibly chosen. To ensure that the control sleeve 43 does not rotate with the control element 41, but moves axially downwards, first and second guide elements 87, 89 are formed on the skirt 55 and on the first sleeve part 59, respectively. For example, the first guide element 87 can be axial grooves and the second guide elements 89 can be axial slats that slide in the grooves. In this position, the control sleeve 43 has already been pushed slightly downwards out of the control element 41 and compresses the spring 37. The upper end of the first control part 49 is pressed against the locking ring 35 from below by the spring, but cannot yet penetrate it.The two guide elements 87,89 therefore act as a guide slot to transform the rotary movement into a linear movement.

[0072] In Figure 3, the pump head 29, including the control element 41, is rotated 270 degrees counterclockwise, and the control sleeve 43 is fully extended downward. This causes the spring 37 to be maximally compressed.

[0073] As can be seen in Figure 4, in this rotational position, the positive engagement between the locking ring 35 and the first control part 49 takes place because the flattened portion 75 coincides with the corresponding part of the through-opening 71. Since the spring 37 is maximally compressed, the first control part 49 is pressed upward with force by the locking ring 35.

[0074] Figure 5 shows that the first control part 49 is fully extended from the locking ring, and accordingly, the upper end of the first sleeve part 59 and the third shoulder 77 abut the underside of the locking ring 35. This is the second upper position of the pump head 29.

[0075] The pumping process can now be started by the user pressing the pressure plate 33 downward (Figure 6). Air is drawn into the housing 13 through an intake opening 91 in the housing 13 to prevent a negative pressure from developing in the dosing chamber 15 during the downward movement of the piston 39. The container 12 is also ventilated through the intake opening 91 to prevent a negative pressure from developing there.

[0076] In Figure 7, the pump head 29 has reached the first lower position, and the suction process of the liquid into the dosing chamber 15 can begin. During the suction process, the inlet valve is open, and liquid is sucked into the dosing chamber 15 through the raised ball 25.

[0077] In Figure 8, the first pumping cycle is complete. If the pump head 29 is pressed downwards, the inlet valve is closed. The outlet valve is open because the piston 39 is in the upper position and is pressed against the second shoulder 57 during the downward movement. This clears the liquid openings 64 and liquid can be pressed through them into the second sleeve part 61, into the second and first control parts 51, 49 and via the pump head 29 into the dispensing opening. For optimal function of the suction and pumping cycles, it is important that the interiors of the first and second sleeve parts 59, 61 are sealed by the 67.In summary, in the inventive pump dispenser 11, a rotary movement of the pump head 29 is transformed into two linear axial movements: On the one hand, the control sleeve 43 is moved linearly downwards by the rotary movement and, on the other hand, the pump head 29 together with the control element 41 and the control sleeve 43 is moved linearly upwards by the locking ring 35.

[0078] Legend:

[0079] 11 pump dispensers

[0080] 12 containers

[0081] 13 housings

[0082] 15 Dosing chamber

[0083] 17 Floor

[0084] 19 Flange

[0085] 21 cap

[0086] 23 Intake manifold

[0087] 25 plastic balls

[0088] 27 Donor opening

[0089] 29 Pump head

[0090] 31 Longitudinal axis

[0091] 33 printing plate

[0092] 35 locking ring

[0093] 37 plastic spring

[0094] 39 pistons

[0095] 41 Control

[0096] 43 control sleeve

[0097] 45 Shell of the control element

[0098] 47 First paragraph

[0099] 49 First control part

[0100] 51 Second control part

[0101] 53 First external thread

[0102] 55 Apron

[0103] 57 Second paragraph First sleeve part

[0104] Second sleeve part

[0105] fountain pen

[0106] Liquid opening

[0107] First internal thread

[0108] seal

[0109] First groove

[0110] passage opening

[0111] Nose

[0112] flattening

[0113] Third paragraph

[0114] Second external thread

[0115] Second internal thread

[0116] rib

[0117] Second groove

[0118] First leadership element

[0119] Second guide element

[0120] Intake opening

[0121] Notch on the first internal thread

[0122] Lower end of the first external thread

Claims

1 . Pump dispenser (11) for the measured withdrawal of a liquid from a container (12) onto which the pump dispenser (11) can be placed, comprising a housing (13) which can be held to the container (12) by means of a cap (21) and in which a dosing chamber (15) is formed, a pump head (29) with a dispensing opening (27), which pump head (29) is movable up and down relative to the housing (13) along the longitudinal axis (31) of the dispenser (11) between a first lower and second upper position to carry out a pumping stroke, is rotatable about the longitudinal axis (31) relative to the housing (13) and has a rotation angle, a piston (39) which is movable together with the pump head (29) in the dosing chamber (15) to convey the liquid, a plastic spring (37) which presses the pump head (29) relative to the housing (13) and is positioned between a lower end of the housing (13) and the piston (39), a closure ring (35) which closes an upper end of the housing (13) and which the pump head (29) penetrates, a suction tube (23) with which liquid can be sucked from the container into the dosing chamber (15), and an inlet valve in the form of a ball (25), which ball (25) defines the conveying direction of the liquid from the suction tube (23) into the dispensing opening (27) and blocks conveying in the opposite direction, characterized in that the pump head (29) is connected in a rotationally fixed manner to a control element (41) having a first external thread (53) and in the form of a cylinder with a jacket (45), and in that a control sleeve (43) having a first internal thread (65) is arranged between the closure ring (35) and the control element (41),wherein the control element (41) is rotatably and centrally mounted within the control sleeve (43) and the first internal and external threads (65, 53) cooperate to define a total length of the control element (41) and the control sleeve (43) as a function of the angle of rotation by a telescopic retraction and extension of the control element (41) from the control sleeve (43), which total length serves to compress the plastic spring (37) according to the total length of the control element (41) and control sleeve (43).

2. Pump dispenser according to claim 1, characterized in that the control element (41) is pressed from below onto the locking ring (35) by the plastic spring (37) and there is a positive connection between the control element (41) and the locking ring (35), which is intended for the control element (41) to extend out of the locking ring (35) in a certain rotational position of the pump head (29) and the pump head (29) is thereby pushed into the second upper position.

3. Pump dispenser according to claim 1 or 2, characterized in that the control element (41) has a first shoulder (47) formed in the circumferential direction, wherein a first control part (49) is provided above the first shoulder (47) and a second control part (51) is provided below the first shoulder (47).

4. Pump dispenser according to one of the preceding claims, characterized in that the control sleeve (43) has a first sleeve part (59) and a second sleeve part (61), which sleeve parts (59, 61) are connected to one another by a second shoulder (57).

5. Pump dispenser according to claim 4, characterized in that the second control part (51) projects into the second sleeve part (61) for axially guiding the control element (41) and is axially displaceable therein.

6. Pump dispenser according to claim 4 or 5, characterized in that a seal (67) is arranged at a lower end of the second control part (51), which seals the interior of the second sleeve part (61) from the interior of the first sleeve part (59).

7. Pump dispenser according to one of claims 4 to 6, characterized in that for the axial and rotationally fixed guidance of the control sleeve (43) on the closure ring (35) an apron (55) is formed, on the inside of which first axially oriented guide elements (87) are provided, which interact with second guide elements (89) formed on the first sleeve part (59).

8. Pump dispenser according to one of claims 2 to 7, characterized in that the positive connection is realized in that the control element (41) is circular in cross section with a flattened area (75) and a through opening (71) of the closure ring (35) has a corresponding negative shape of a cross section of the control element (41).

9. Pump dispenser according to claim 8, characterized in that a lower end of the flattened portion (75) is delimited by a third shoulder (77).

10. Pump dispenser according to one of claims 2 to 7, characterized in that the positive connection is realized in that the control element (41) has a first groove (69) on its casing (45), in which a nose (73) formed in the through opening (71) is guided.

11. Pump dispenser according to one of claims 2 to 7, characterized in that the positive connection is realized in that a second external thread (79) is formed at an upper end of the casing (45) of the control element (41), which second external thread (79) cooperates with a second internal thread (81) which is formed at the edge of the through-opening (71).

12. Pump dispenser according to claim 11, characterized in that a rib (83) extending in the axial direction is formed on the casing (45), which rib can connect the first external thread (53) to the second external thread (79).

13. Pump dispenser according to claim 12, characterized in that a second groove (85) is provided on the closure ring (35), in which the rib (83) is guided.

14. Pump dispenser according to one of the preceding claims, characterized in that the plastic spring (37) is connected to the control sleeve (43) by a spring holder (63).

15. Pump dispenser according to claim 14, characterized in that the piston (39) on the control sleeve (43) is displaceable between a first and a second position, wherein in the first position it abuts the spring holder (63) when the pump head (29) is pressed upwards and in the second position it abuts the second shoulder (57) when the pump head (29) is pressed downwards.

16. Pump dispenser according to claim 15, characterized in that at least one liquid opening (64) is provided on the control sleeve (43), which acts together with the piston (39) as an outlet valve.

17. Pump dispenser according to one of claims 2 to 16, characterized in that the pump head (29) is pressed against the locking ring (35) by the spring (37) during rotation and is locked in the direction of rotation when the positive locking takes effect and is pressed axially upwards by the spring (37).

18. Pump dispenser according to one of the preceding claims, characterized in that in a transport position of the pump head (29) it is retracted into the locking ring (35) and the pump head (29) in the transport position assumes the angle of rotation of 0 degrees relative to the locking ring (35) and the control element (41) in the transport position is completely retracted into the control sleeve (43), whereby the plastic spring (37) is relaxed.

19. Pump dispenser according to one of the preceding claims, characterized in that when the pump head (29) is rotated counterclockwise, the control element (41) can be screwed out of the control sleeve (43), whereby the plastic spring (37) is compressed more the further the pump head (29) is rotated.

20. Pump dispenser according to one of the preceding claims, characterized in that the angle of rotation of the pump head (29) has a specific value, in particular 270 degrees, when the control element (41) is fully extended axially from the control sleeve (43) and the plastic spring (37) is maximally compressed.

21. Pump dispenser according to claim 2 and 20, characterized in that the angle of rotation of the pump head (29) has a specific value, in particular a value of 270 degrees, when the positive connection between the locking ring (35) and the control element (41) engages.

22. Pump dispenser according to one of claims 2 to 21, characterized in that the positive connection between the locking ring (35) and the control element (41) only takes effect when the control element (41) is fully extended axially from the control sleeve (43).

23. Pump dispenser according to one of the preceding claims, characterized in that a notch (93) is provided on the first internal thread (65), in which notch a lower end (95) of the first external thread (53) can be locked.

24. Pump system comprising a container (12) and a pump dispenser (11) attached to the container (12) according to one of the preceding claims.

Images