Plastic spring

Abstract

The invention relates to a plastic spring (11) for use in a pump dispenser (13), having a first spring element (15) and a second spring element (17), which can be pushed into one another in the axial direction, wherein the spring force is generated in that when the two spring elements (15, 17) are pushed into one other in the axial direction, the first and / or the second spring element (15, 17) elastically expands in the radial direction. The first and the second spring element have, respectively, a first and second cone (15, 17) with a first and second tip (15, 17), wherein the first and second tip (19, 21) face one another and the first cone (15) can be axially pushed into the second cone (17) or the second cone (17) can be axially pushed into the first cone (15).

Description

[0001] plastic spring

[0002] Field of the invention

[0003] The invention relates to a plastic spring for use in a pump dispenser according to the preamble of claim 1 and a pump dispenser according to the preamble of claim 12.

[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. The dispenser extension is formed on the dispenser head and therefore moves with it. A metal spring is integrated into the dispenser to reset the dispenser head. The valve function, which is necessary to ensure that the liquid is pumped into the dispenser extension when the head is pressed and that liquid is drawn back into the pump dispenser when the head is returned, is implemented by metal or glass beads.

[0006] A separate disposal of such pump dispensers known from the state of the art is not possible or only possible with great effort, since the metal spring and the valve balls would have to be removed from the pump dispenser.

[0007] Pump dispensers with plastic balls with a valve function and adapted plastic springs already exist. To ensure the plastic spring functions reliably and has good long-term load-bearing capacity, the pump dispenser must be adapted to the plastic spring. This involves considerable effort, as a pump dispenser must be specifically developed and produced for the plastic spring. Furthermore, traditional plastic springs, typically designed as spiral spring elements, prove to be very complex to manufacture. Complex injection molding and manufacturing technology are required to produce such helical spring structures.

[0008] Object of the invention

[0009] The disadvantages of the described prior art give rise to the task of creating a plastic spring which is of simple construction and can be produced and manufactured as easily as possible, does not require any complex and accordingly expensive adaptation of the pump dispenser, and can be compressed and decompressed without disturbing jerky movements.

[0010] Description

[0011] The stated problem is solved in a plastic spring for use 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.

[0012] The invention is preferably characterized in that the first and second spring elements have a first and second cone, respectively, with a first and second tip, wherein the first and second tips face each other and the second cone can be displaced axially into the second cone or the second cone can be displaced axially into the first cone. By providing the two cones, the plastic spring has a particularly simple design and can be manufactured cost-effectively. Since the spring consists of only two components, it operates particularly reliably, ensuring a large number of pumping cycles.

[0013] In a preferred embodiment of the invention, the first cone is a truncated cone with a first end or first tip having a smaller diameter and a second end having a larger diameter, which is formed from at least a first lateral surface and is open at its first end, with at least one slot extending from the first to the second end being provided on the first lateral surface. The conical shape simply enables the spring force of the spring to be greatest when the penetration depth is greatest. As a result, the restoring force is greatest when the suction of product into the dosing chamber begins and the highest suction force is required.

[0014] It is of course also conceivable for the second cone to be a truncated cone with a third end or second tip having a smaller diameter and a fourth end having a larger diameter, which is formed from at least one second lateral surface and is open at its third end, with at least one slot extending from the third to the fourth end being provided on the second lateral surface. For the function of the plastic spring, it makes no difference on which of the two cones the at least one slot is provided.

[0015] It has proven advantageous if the at least one slot is closed at the first or third end and open at the second or fourth end. This creates at least one spring wing on the cone casing, which can be bent open at the second or fourth end. A joint is formed at the first or third end, around which the spring wing can pivot in the radial direction. Because the joint is bent in the circumferential direction of the cone, it has a restoring force and the spring wing is pressed into its original position. The spring wing can exert a compressive force on the other cone at its open end, whereby the inner cone is pushed out of the outer cone. This creates an axial force that pushes the inner cone out of the outer cone.

[0016] In a further particularly preferred embodiment of the invention, four slots are provided on the first or second cone, with a spring wing formed between each slot. This number of slots or spring wings generates an optimal spring force. A different number of slots or spring wings is also conceivable in order to generate the appropriate spring force for the respective application. In particular, by specifically varying the design of the two cone structures, the spring force can be adjusted according to a defined target value. The wall thickness of the slotted cone, the number of slots, cone angle, diameter of the cone, as well as the plastic used itself influence the flexural rigidity of the cone wing elements and thus have a significant impact on the resulting spring force.

[0017] It has proven useful to provide a shoulder at the second or fourth end to limit the axial movement of the two cones relative to each other. This makes it easy to specify the minimum height of the plastic spring when it is fully compressed.

[0018] For convenience, the first and second cones are essentially the same height. This allows for the minimum amount of plastic required to manufacture the cones, as neither cone is unnecessarily tall.

[0019] In another particularly preferred embodiment of the invention, the first cone is implemented as a first and second sleeve. At least the cone into which the other cone penetrates must be designed as a sleeve. To ensure that the product can be conveyed between the cones from the inlet of the dosing chamber to the outlet of the dosing chamber, both cones must be hollow and have the shape of a sleeve.

[0020] It is advantageous if a first or second retaining element is connected to the first or third end. This allows the plastic spring to be integrated into a commercially available pump dispenser. The retaining elements can be designed so that they are firmly attached to the pump dispenser, thus axially stabilizing the plastic spring and preventing it from collapsing radially when compressed.

[0021] It is advantageous if the first and second retaining elements are a first and second cylinder shell, which can be positively connected to components of the pump dispenser. For example, the first cylinder shell can be attached to the piston, and the second cylinder shell is connected to the bottom of the dispensing chamber.

[0022] It is preferred if the plastic spring is made of polypropylene or polyethylene. If the present plastic spring according to the invention is used in a pump dispenser made of the same material as the plastic spring, this is known to be ideal for recycling the plastic spring or pump dispenser. Alternative materials can also be engineering plastics such as polyester, polyoxymethylene, or polyamide. Polyoxymethylene or polyamide, in particular, are friction-resistant, meaning that the two cones are not damaged by the friction of the spring wings against the corresponding cone casing. The spring can withstand up to 5,000 operating cycles without being destroyed.

[0023] A further aspect of the invention relates to a pump dispenser according to the preamble of claim 12. The invention is also characterized in that the spring is a plastic spring according to the above description, and the first and second balls are made of plastic. The spring has the advantage that it can be inserted into the dispensing chamber of a previously known and accordingly commercially available pump dispenser. In such a pump dispenser, all components are made of plastic. Accordingly, the pump dispenser can be disposed of separately and recycled without effort.

[0024] Further advantages and features will become apparent from the following description of an embodiment of the invention with reference to the schematic representations. These are not to scale:

[0025] Figure 1 : a plastic spring in an isometric view;

[0026] Figure 2: a bottom view of the plastic spring from Figure 1;

[0027] Figure 3: a top view of the plastic spring from Figure 1;

[0028] Figure 4: a side view of the plastic spring from Figure 1; Figure 5: a sectional view of the spring from Figure 1 along the section line IV-IV;

[0029] Figure 6: a sectional view of an embodiment of a pump dispenser in which the plastic spring is installed.

[0030] Figures 1 to 6 show a plastic spring, designated overall by reference numeral 11. The plastic spring is intended to be installed in a pump dispenser 13, as shown in Figure 6. The plastic spring 11 comes into contact with the product to be pumped.

[0031] The plastic spring 11 has a first and second cone 15, 17. The two cones preferably each have the shape of a truncated cone, with a first and third end 19, 21 whose diameters are smaller than the diameters of the second and fourth ends 23, 25. The first and third ends can also be referred to as tips.

[0032] The first and third ends 19, 21 face each other, and the second cone 17 is axially displaceable into the first cone 15. The first and second cones are preferably realized as a first and second sleeve 13, 15, i.e., the two cones are hollow.

[0033] The first cone 15 has a plurality of slots 26, preferably four slots 26. Between each two adjacent slots 26, a spring wing 27 is formed, which is pivotable in the radial direction at the second end 23. The slots 26 are open at the first end 19 and closed at the second end 23. This allows the spring wings 27 to fold outward when the second cone 17 penetrates the first cone 15.

[0034] At the fourth end 25, a shoulder 28 is provided, which limits the penetration depth of the second cone 17 into the first cone 15 in the axial direction. At the end of the penetration path, the first end 19 abuts the shoulder 28. It is preferred if the first height 29 of the first cone 15 and the second height 30 of the second cone 17 are the same height.

[0035] A first and second holding element in the form of a first and second cylinder jacket 31a, 31b are respectively connected to the second and fourth ends 23, 25. The cylinder jackets can be plugged onto components of the pump dispenser 13, whereby the spring 11 is stabilized in the axial direction when pushed together and apart. In Figure 8, the spring 11 is integrated into a pump dispenser 13. The pump dispenser has a housing 35, which is held to a container by a cap 37. This is preferably a screw cap 37, which can be screwed onto the container neck. A dosing chamber 39 is formed in the housing 35. The dispenser 13 further comprises a pump head 41, which is movable up and down relative to the housing 35 along the longitudinal axis 43 of the dispenser 11 between a first and second position to execute a pump stroke.A piston 45, which is attached to the pump head 41, is movable in the dosing chamber 39 to deliver the liquid. A dispensing opening 47 is connected to the dosing chamber 39. The dosed liquid can exit the pump dispenser 13 through the dispensing opening 47. The plastic spring 11 resets the pump head 41 relative to the housing 35. A valve is implemented by a first and second plastic ball 49a, 49b. The balls 49a, 49b define the delivery direction of the liquid from the container into the dispensing opening 47 and block delivery in the opposite direction. The liquid is sucked from the container into the dosing chamber via a suction pipe 51.

[0036] If the pump head 41 is pressed downwards, the second cone 17 penetrates the first cone 15. The pressure pushes the spring vanes 27 outwards and, due to their articulated connection to the second end 23, they are pre-tensioned. The second cone 17 can be moved axially into the first cone 15 until the first end 19 strikes the shoulder 28. If there is no axial pressure on the pump head 41, the pre-tensioned spring vanes 27 return to their basic position. The conical design of the second sleeve 17 allows them to push the latter upwards. Polypropylene or polyethylene is a suitable polymer for producing the spring 11. Since the open ends of the spring vanes 27 rub against the outer surface of the second cone 17, it is advantageous if the plastic spring 11 is made of a friction-resistant plastic, for example polyoxymethylene or polyamide.

[0037] In the dosing chamber 39, the plastic spring 11 comes into contact with the liquid.

[0038] The pump dispenser 13 is constructed entirely of plastic parts, as the spring 11 and the balls 49a, 49b are also made of plastic. This allows for easy, separate disposal of the pump dispenser. The laborious separation of metal parts is eliminated. The plastic spring 11 has the further advantage of being designed to be integrated into a commercially available pump dispenser 13. The pump dispenser 13 can therefore be adopted from mass production.

[0039] Legend:

[0040] 11 plastic spring

[0041] 13 pump dispensers

[0042] 15 First cone, first truncated cone, first sleeve, first spring element

[0043] 17 Second cone, second truncated cone, second sleeve, second spring element

[0044] 19 First end of the first cone, first tip

[0045] 21 Third end of the second cone, second tip

[0046] 23 Second end of the first cone

[0047] 25 Fourth end of the second cone

[0048] 26 slots

[0049] 27 feather wings

[0050] 28 paragraph

[0051] 29 First Height

[0052] 30 Second Height

[0053] 31a, 31b First and second cylinder shell, first and second retaining element

[0054] 35 housings

[0055] 37 cap

[0056] 39 Dosing chamber

[0057] 41 Pump head

[0058] 43 Longitudinal axis

[0059] 45 pistons

[0060] 47 Donor opening

[0061] 49a, 49b First and second plastic ball

[0062] 51 intake manifold

Claims

1 . Plastic spring (11) for use in a pump dispenser (13) comprising - a first spring element (15) and a second spring element (17) which can be pushed into one another in the axial direction, the spring force being generated in that the first and / or the second spring element (15, 17) is elastically expanded in the radial direction when the two spring elements (15, 17) are pushed into one another in the axial direction, characterized in that the first and the second spring element have a first and a second cone (15, 17) with a first and a second tip (15, 17), the first and second tips (19, 21) facing one another and the first cone (15) being displaceable axially into the second cone (17) or the second cone (17) being displaceable axially into the first cone (15).

2. Plastic spring according to claim 1, characterized in that the first cone is a truncated cone (15) with a first end (19) or the first tip with a smaller diameter and a second end (23) with a larger diameter, which is formed from at least a first lateral surface and is open at its first end (19), wherein at least one slot (26) extending from the first to the second end (19, 23) is provided on the first lateral surface.

3. Plastic spring according to claim 1, characterized in that the second cone is a truncated cone (17) with a third end (21) or the second tip with a smaller diameter and a fourth end (25) with a larger diameter, which is formed from at least a second lateral surface and is open at its third end (21), wherein at least one slot (26) extending from the third to the fourth end (21, 25) is provided on the second lateral surface.

4. Plastic spring according to claim 2 or 3, characterized in that the at least one slot (26) is closed at the first or third end and is open at the second or fourth end (23, 25).

5. Plastic spring according to one of claims 2 to 4, characterized in that four slots (26) are provided on the first or second cone (15, 17), wherein a spring wing (27) is formed between each of the slots (26).

6. Plastic spring according to one of the preceding claims, characterized in that a shoulder (28) is provided at the second or at the fourth end (23, 25), which limits the axial movement of the two cones (15, 17) relative to one another.

7. Plastic spring according to one of the preceding claims, characterized in that the first and the second cone (15, 17) have substantially the same height (29, 30).

8. Plastic spring according to one of the preceding claims, characterized in that the first and the second cone are realized as a first and second sleeve (15, 17).

9. Plastic spring according to one of claims 2 to 8, characterized in that a first or a second holding element (31a, 31b) adjoins the first or third end (19, 21).

10. Plastic spring according to claim 9, characterized in that the first and second holding element are a first and second cylinder jacket (31a, 31b) which can be positively connected to components of the pump dispenser (13).

11. Plastic spring according to one of the preceding claims, characterized in that the plastic spring (11) is made of polypropylene, polyethylene, polyoxymethylene or polyamide.

12. Pump dispenser (13) for the metered withdrawal of a liquid from a container onto which the pump dispenser (13) can be placed, comprising a housing (35) which is held to the container by a cap (37) and in which a metering chamber (39) is formed, a pump head (41) which is movable up and down relative to the housing (35) along the longitudinal axis (43) of the dispenser (13) between a first and second position to carry out a pump stroke, a piston (45) which is fixed to the pump head (41) and is movable in the metering chamber (39) to convey the liquid, a dispensing opening (47) which is connected to the dosing chamber (39) and through which dosed liquid can leave the pump dispenser (13), a spring (11) which resets the pump head (41) relative to the housing (35) - a suction pipe (51) with which liquid is sucked from the container into the dosing chamber (39) and a valve in the form of a first and second ball (49a, 49b), which balls (49a, 49b) define the conveying direction of the liquid from the container into the dispensing opening (37) and block conveying in the opposite direction, characterized in that the spring is a plastic spring (11) according to one of the preceding claims and the first and second balls (49a, 49b) are made of plastic.

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