Plastics spring

Abstract

The invention relates to a plastics spring (11) for use in a pump dispenser (13) comprising a first spring element (15a) and a second spring element (15b), which can be pushed one into the other axially from a basic position, the spring force being generated in that, when the two spring elements (15a, 15b) are pushed one into the other axially, the first and the second spring element (15, 17) elastically deform. The first and the second spring element (15a, 15b) have a respective horizontal holding element (17a, 17b). An equal plurality of spring feet (19) protrude from each holding element (17a, 17b), which spring feet (19) have a curvature and an open end (21).

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 16.

[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 using 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 durability, 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.

[0008] Furthermore, traditional plastic springs, typically designed as spiral spring elements, prove to be very complex to manufacture. Complex injection molding, tooling, and manufacturing technology are necessary to produce such helical spring structures. The 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, does not require complex and accordingly expensive adaptation of the pump dispenser and can withstand the highest possible number of pumping cycles.

[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 each have a horizontal retaining element, and in that an equal number of spring feet protrude from each retaining element, each spring foot having a curve and an open end. The spring feet enable a simple design of a plastic spring comprising only two components. The size of the restoring force can be easily determined by selecting the number of spring feet. Due to the minimal contact between corresponding spring feet of the two spring elements, frictional resistance is low, and the plastic spring can be compressed with little force.

[0013] In a preferred embodiment of the invention, two corresponding spring feet of the first and second retaining elements can be bent relative to each other when axially pushed into each other, provided the first and second spring elements are arranged in a first rotational position relative to each other. This allows a plastic spring to be realized with simply constructed and correspondingly cost-effective spring elements. The spring force can be activated by simply twisting them axially relative to each other. The spring force can be deactivated just as easily by twisting them.

[0014] In a further particularly preferred embodiment of the invention, the two corresponding spring feet of the first and second spring element slide against each other on radially oriented sliding lines when the spring elements are pushed together. The sliding lines are provided on the inwardly bent free end of the spring foot. As a result, the contact of two corresponding spring feet on the sliding line is minimized and the frictional resistance when the two spring elements are pushed together is particularly low. It is preferred if each spring foot has a first and second radially and axially oriented side, wherein the first side is shorter than the second side and the sliding line is provided on the first side at the open end. A radially and axially oriented side means that the spring foot has two sides orIt has surfaces that each have a radial extension and also extend essentially axially toward the open end. As a result, each spring foot rests on a cylinder surface defined by the spring feet, and each spring foot is bent while lying on the cylinder surface. This orientation ensures that the corresponding spring feet bend against each other and do not deflect or buckle.

[0015] In another particularly preferred embodiment of the invention, the spring feet are tension-free when the first and second spring elements are arranged in a second rotational position relative to each other and are shifted into each other. This allows the spring feet to be protected while the pump dispenser is in storage and not yet sold to the user. In this tension-free, protective position, creep of the plastic of the spring feet is prevented. This extends the service life of the plastic spring during use of the pump dispenser.

[0016] It is advantageous if switching between the first and second positions is possible by axially rotating the spring elements relative to each other, with the rotation angle preferably being between 40 and 50 degrees. Rotating the spring elements by rotating the pump head is easy for the user. If four spring feet are provided per spring element, a rotation between 40 and 50 degrees ensures that the corresponding spring feet are pressed together in the first rotational position and are not in contact with each other in the second rotational position.

[0017] In another particularly preferred embodiment of the invention, the first and second spring elements are identical. This allows the first and second spring elements to be manufactured in a single injection mold, making production particularly cost-effective.

[0018] It is particularly preferred if the spring feet of a spring element are alternately curved convexly and concavely. This allows corresponding spring feet of the two spring elements to wedge into each other, and the two spring elements are held together in the first rotational position without separating. When rotating to the second rotational position, the spring feet must partially snap over the open end of the corresponding spring feet so that all spring feet are free of tension. This has the advantage that the user receives haptic feedback regarding the relative position of the spring elements.

[0019] It is advantageous if two corresponding spring feet of the first and second spring elements are both convexly or concavely curved. This creates the mutual bending of the two spring feet when the spring elements are pushed together.

[0020] For optimal performance, the first and second spring elements have the same even number of spring feet. This keeps the spring elements balanced, and the symmetrical design prevents radial forces from occurring.

[0021] It is advantageous if the spring feet have a rectangular or square cross-section. This creates the desired radial sliding lines described above, and the spring feet are neither forced radially outward nor radially inward from their position on the cylinder surface.

[0022] It is also advantageous if the spring legs taper or thicken toward the open end. This allows the spring force to be varied over the stroke, or the spring force increases or decreases with the relative stroke of the two spring elements. In most cases, the cross-section will remain constant along the length of the spring legs.

[0023] In a further preferred embodiment, the first and second retaining elements are a first and second circular ring, respectively, and the spring feet of a spring element, together with the circular ring, define a rotating cylinder shape, with the spring feet resting on the cylinder surface. This cylindrical design of the plastic spring allows the spring to be integrated into existing pump dispensers.

[0024] It has proven advantageous if the first and second circular rings can be connected to components of the pump dispenser in a form-fitting manner. This allows the plastic spring to be quickly installed into the pump dispenser. The first circular ring and the second circular ring therefore serve a dual function: On the one hand, the spring feet are held to the circular ring, and on the other hand, the circular ring serves as a connection between the spring and the pump dispenser.

[0025] It is preferable for the plastic spring to be made of polypropylene, polyethylene, polyoxymethylene, or polyamide. These plastics are easy to injection mold. Polyoxymethylene or polyamide, in particular, are abrasion-resistant, meaning the two cones are not damaged by the friction of the spring wings against the corresponding cone casing. This allows the spring to withstand up to 5,000 operating cycles without being destroyed.

[0026] A further aspect of the invention relates to a pump dispenser according to the preamble of claim 16. The invention is also characterized in that the spring has a

[0027] The spring is made of plastic as described above, 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 known and 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 any effort.

[0028] 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:

[0029] Figure 1 : a plastic spring with a first and second spring element in a side view

[0030] Figure 2: an isometric view of the spring of Figure 1;

[0031] Figure 3: a side view of the spring with the spring elements in a first

[0032] Positioned in a rotational position in which two corresponding spring feet bend each other;

[0033] Figure 4: a sectional view of the spring from Figure 3 along the section line

[0034] IV-IV;

[0035] Figure 5: an isometric view of the spring in the first rotational position;

[0036] Figure 6: a side view of the spring in a second rotational position in which the spring feet are stress-free;

[0037] Figure 7: an isometric view of the spring in the second rotational position and

[0038] Figure 8: A sectional view of an embodiment of a pump dispenser in which the plastic spring is incorporated. Figures 1 to 8 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 8. The plastic spring 11 comes into contact with the product to be pumped.

[0039] The plastic spring 11 has a first and second spring element 15a, 15b. The two spring elements 15a, 15b can be pushed into each other from a basic position, thereby building up an axial restoring force.

[0040] The two spring elements 15a, 15b each have a horizontal holding element in the form of a first and second circular ring 17a, 17b. Preferably, the two spring elements 15a, 15b are identical, whereby only a single injection mold is required for their production. On the one hand, the spring elements 15a, 15 can be attached to or plugged onto components of the pump dispenser 13 using the circular rings 17a, 17b, and on the other hand, a plurality of spring feet 19 are each connected to the circular rings 17a, 17b, which protrude from the circular rings 17a, 17b. It is preferred if the first and second spring elements 15a, 15b have the same even number of spring feet 19. The figures show that the spring elements each have four spring feet. The figures also show that the spring feet 19 are oriented essentially at right angles to the circular rings and have a curvature or are bent.Each spring foot 19 has a radially oriented sliding line 23 at its open end 21. Since the spring feet 19 are curved, they have a first and second radially and axially oriented side 25, 27, wherein the first side 25 is shorter than the second side 27 and the second side 27 is longer than the first side 25. A radially and axially oriented side means that the spring foot 19 has two sides 25, 27 or surfaces, each of which has a radial extension and additionally extends essentially axially in the direction of the open end 21. The sliding line 23 is provided at the open end 21 on the shorter first side 25. The spring feet 19 of a spring element 15 are alternately convexly and concavely curved.

[0041] The spring feet 19 have a rectangular or square cross-section. Each spring foot 19 of the first spring element 15a interacts with a corresponding spring foot 19 of the second spring element 19, creating the spring action of the spring 11. The corresponding spring feet 19 are both convexly or concavely curved. The spring feet 19 of the first and second spring elements, together with the circular ring, define a rotary cylinder shape, with the spring feet resting on the cylinder surface. The spring feet 19 can have a cross-section that changes from the first or second circular ring 17a, 17b towards the open end 21. The cross-section can decrease or increase from the bottom so that the spring force changes over the stroke. For example, the spring force can increase the more the two spring elements 15a, 15b are compressed.

[0042] 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 that 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 fixed to the pump head 41, is movable in the dosing chamber 39 to convey the liquid. A dispensing opening 47 is connected to the dosing chamber 39. The dosed liquid can leave the pump dispenser 13 through the dispensing opening 47. The plastic spring 11 returns the pump head 41 relative to the housing 35. A valve is realized by a first and second plastic ball 49a, 49b.The balls 49a, 49b define the direction of flow of the liquid from the container into the dispensing opening 47 and block flow in the opposite direction. The liquid is drawn from the container into the dispensing chamber via a suction tube 51.

[0043] The two spring elements can be rotated, for example, by rotating the pump head 41 between a first and second rotational position 29, 31. The angle of rotation is preferably 45 degrees. If the pump head 41 is pressed downwards, two corresponding spring feet of the first and second holding element are bent against each other when they are axially pushed into one another from their basic position when the first and second spring elements are arranged relative to one another in the first rotational position 29. This is shown in Figures 3, 4 and 5. The sliding line 23 slides on the second, longer side 27 of the corresponding spring foot 19. Since the two corresponding spring feet 19 only touch via the sliding line 23, the friction when the first and second spring elements 15a, 15b are pushed into one another is minimized.

[0044] If there is no axial pressure on the pump head 41, the pre-tensioned spring feet 19 return to their home position. Due to their curved design, they can push the first spring element 15a upwards. If the two holding elements 15a, 15b are in the second rotational position 31, the corresponding spring feet 19 do not touch and the first spring element 15a can fall downwards into the second spring element 15b without resistance. The two spring elements 15a, 15b are then in a storage position in which the spring feet 19 are free of tension. This can prevent creep of the plastic. Since the spring 11 is only activated by the consumer, its service life can be significantly increased.

[0045] Polypropylene or polyethylene is a suitable polymer for manufacturing 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, such as polyoxymethylene or polyamide.

[0046] In the dosing chamber 39, the plastic spring 11 comes into contact with the liquid.

[0047] 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, clean disposal of the pump dispenser. The laborious separation of metal parts is eliminated.

[0048] 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.

[0049] Legend:

[0050] 11 plastic spring

[0051] 13 pump dispensers

[0052] 15a, 15b First spring element, second spring element

[0053] 17a, 17b First and second circular ring, first and second holding element

[0054] 19 spring feet

[0055] 21 Open end of a spring foot

[0056] 23 Gliding line

[0057] 25 First page of the spring foot

[0058] 27 Second side of the spring foot

[0059] 29 First turning position

[0060] 31 Second turning position

[0061] 35 housings

[0062] 37 cap

[0063] 39 Dosing chamber

[0064] 41 Pump head

[0065] 43 Longitudinal axis

[0066] 45 pistons

[0067] 47 Donor opening

[0068] 49a, 49b First and second plastic ball

[0069] 51 intake manifold

Claims

1. Plastic spring (11) for use in a pump dispenser (13) comprising - a first spring element (15a) and a second spring element (15b) which can be pushed into one another in the axial direction from a basic position, the spring force being generated by the first and the second spring element (15, 17) elastically deforming when the two spring elements (15a, 15b) are pushed into one another in the axial direction, characterized in that the first and the second spring element (15a, 15b) each have a horizontal holding element (17a, 17b) and that an equal plurality of spring feet (19) protrudes from each holding element (17a, 17b), which spring feet (19) have a curvature and an open end (21).

2. Plastic spring according to claim 1, characterized in that two corresponding spring feet (19) of the first and second holding elements (17a, 17b) can be bent relative to one another when they are axially pushed into one another, when the first and second spring elements (15a, 15b) are arranged in a first rotational position (29) relative to one another.

3. Plastic spring according to claim 1 or 2, characterized in that the two corresponding spring feet (19) of the first and second spring elements (15a, 15b) slide against each other on radially oriented sliding lines (23) when the spring elements (15a, 15b) are pushed into one another.

4. Plastic spring according to one of the preceding claims, characterized in that each spring foot (19) has a first and second radially and axially oriented side (25, 27), wherein the first side (25) is shorter than the second side (27) and the sliding line (23) is provided on the first side (25) at the open end (21).

5. Plastic spring according to one of the preceding claims, characterized in that the spring feet (19) are stress-free when the first and second spring elements (15a, 15b) are arranged in a second rotational position (31) relative to one another and are displaced into one another.

6. Plastic spring according to one of claims 2 to 5, characterized in that a change between the first and the second rotational position (29, 31) is made possible by an axial rotation of the spring elements (15a, 15b) relative to one another, wherein the angle of rotation is preferably between 40 and 50 degrees.

7. Plastic spring according to one of the preceding claims, characterized in that the first and second spring elements (15a, 15b) are identical.

8. Plastic spring according to one of claims 2 to 4, characterized in that the spring feet (19) of a spring element (15a, 15b) are alternately convex and concave.

9. Plastic spring according to one of the preceding claims, characterized in that two corresponding spring feet (19) of the first and second spring elements (15a, 15b) are both convexly or concavely curved, whereby the mutual bending of the two spring feet (19) is produced when the spring elements (15a, 15b) are pushed into one another.

10. Plastic spring according to one of the preceding claims, characterized in that the first and second spring elements (15a, 15b) have the same even number of spring feet (19). 11 . Plastic spring according to one of the preceding claims, characterized in that the spring feet (19) have a rectangular or square cross-section.

12. Plastic spring according to one of the preceding claims, characterized in that the spring feet (19) taper or thicken in the direction of the open end (21).

13. Plastic spring according to one of the preceding claims, characterized in that the first and second holding element is a first and second circular ring (17a, 17b), and the spring feet (19) of a spring element (15a, 15b) together with the circular ring (17a, 17b) define a rotary cylinder shape, wherein the spring feet (19) lie on the cylinder jacket.

14. Plastic spring according to claim 13, characterized in that the first and second circular rings (17a, 17b) can be positively connected to components of the pump dispenser (13).

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

16. 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 a 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 dispenser opening (47) which is connected to the metering chamber (39) and through which metered liquid can leave the pump dispenser (13), a spring (11) which resets the pump head (41) relative to the housing (35), a suction tube (51) with which liquid can be drawn from the container into the metering chamber (39). is sucked 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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