Plastic spring

Abstract

The invention relates to a plastic spring (11) for use in a pump dispenser (13), comprising: a plurality of spring legs (19) arranged in a plurality of planes (E), wherein the spring legs (19) of adjacent planes (E) are interconnected at the transition between adjacent planes (E); a first ring (15) which forms the upper end of the spring (11); and a second ring (17) which forms the lower end of the spring (11). Two adjacent spring legs (19) of at least one plane (E) diverge from an upper node (21) at the upper end of the plane (E) and converge at a lower node (21) at the lower end of the plane (E).

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 15.

[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] Separate disposal of such state-of-the-art pump dispensers is not possible, or only with considerable effort, because the metal spring and valve balls would have to be removed from the pump dispenser. It is also impractical that the dispenser extension moves with the head, as this often causes liquid to miss its target (e.g., a user's hand) and contaminate the area surrounding the target.

[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] Object of the invention

[0009] The disadvantages of the described prior art give rise to the task of creating a plastic spring that does not require complex and therefore expensive adjustment of the pump dispenser and can withstand a high number of actuation cycles of the pump dispenser. Description

[0010] 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.

[0011] The invention is preferably characterized in that two adjacent spring legs of at least one level diverge from an upper node at the upper end of the level and converge at a lower node at the lower end of the level. The provision of the nodes gives the spring permanent stability and restoring force, thus withstanding up to 5,000 actuation cycles. In addition, the nodes ensure that the spring expands only minimally in the radial direction during compression. This ensures that the spring integrated into the dosing chamber of the pump dispenser does not interfere with the pumping process and does not touch the wall of the dosing chamber.

[0012] In a particularly preferred embodiment of the invention, four spring legs converge at a node, with two spring legs from two adjacent levels converging at the node. This reinforces each node, giving the plastic spring additional stability and virtually identical properties to a spring made of spring steel.

[0013] It is advantageous if two adjacent levels are separated by a retaining ring. The retaining rings contribute to the spring's further stability and durability. For example, they help prevent the spring from buckling from the vertical in the compressed position and allow the spring legs to rest on adjacent retaining rings in the compressed position.

[0014] In another particularly preferred embodiment of the invention, four spring legs are arranged in each tier of the plastic spring. This allows for the realization of a particularly stable plastic spring with increased restoring force.

[0015] It has proven useful to have protrusions at the ends of the four spring struts on a tier to space the struts apart when compressed. Since the spring or struts come into contact with the product to be pumped in the dosing chamber, the spacing between the protrusions prevents the product from sticking together or otherwise obstructing the struts. It is advantageous if opposing protrusions rest on the retaining ring in between, as the retaining ring prevents the protrusions from moving out of alignment or slipping off one another. It is advisable to provide slots between the ends of the four spring struts on a tier and the two retaining rings that define the tier. The slots make the movement of the spring ends more flexible when the spring is compressed.

[0016] In a further preferred embodiment of the invention, the plastic spring is composed of tiers with four spring legs and two spring legs. The different tiers can be combined to form the spring in any desired configuration. This allows the spring's restoring force to be precisely adapted to the requirements of the pump dispenser.

[0017] It is advantageous if the nodes of two adjacent retaining rings are offset by 90 degrees. This gives the spring a symmetrical and stable structure.

[0018] It is also advantageous if the two nodes of a retaining ring form an angle of 180 degrees, which further improves the spring stability.

[0019] Because the first and second rings and the retaining rings have identical outer diameters and are arranged concentrically one above the other, the spring has the outer dimensions of a rotating cylinder with a circumferential surface. This facilitates the integration of the spring into a standard pump dispenser.

[0020] It is advantageous if the spring struts extend along the outer surface of the plastic spring. This prevents the spring struts from protruding from the outer surface. Preferably, the spring struts remain on the outer surface even in the compressed position, and the outer diameter of the spring remains essentially unchanged.

[0021] In a further preferred embodiment of the invention, the spring struts have a pitch angle of between 30 and 40 degrees, and preferably between 32 and 38 degrees, in the relaxed position of the spring. This gives the spring a compression ratio (the ratio of the lengths of the spring in the unloaded position and in the compressed position) that corresponds to a conventional steel spring.

[0022] The invention is also preferably characterized in that the plastic spring is made of a polyetherimide (PEI). Prepolymer 1,4-bis(4-nitrophthalimido)-phenylene with the trade name IILTEM is particularly preferred. The use of this high-performance plastic with outstanding mechanical strength, in combination with the features described above, enables up to 5000 operating cycles of the spring without it being destroyed. A further aspect of the invention relates to a pump dispenser according to the preamble of claim 15. 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. 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.

[0023] Figure 1 : a plastic spring in a first embodiment and in a

[0024] side view;

[0025] Figure 2: a sectional view of the spring from Figure 1 along the section line ll-ll;

[0026] Figure 3: an enlarged view of detail III from Figure 1;

[0027] Figure 4: an isometric view of the spring from Figure 1;

[0028] Figure 5: the plastic spring in a second embodiment and in a

[0029] side view;

[0030] Figure 6: a sectional view of the spring from Figure 5 along the section line

[0031] Vl-Vl;

[0032] Figure 7: an isometric view of the spring from Figure 5 and

[0033] Figure 8: a sectional view of a pump dispenser in which the plastic spring is installed. Figures 1, 2 and 4 to 7 show a plastic spring which is designated overall by the reference numeral 11. The plastic spring is intended to be installed in a pump dispenser 13, as shown in Figure 7. The plastic spring 11 comes into contact with the product to be pumped. The plastic spring 11 is divided into several levels E. The uppermost level E1 and the lowermost level E2 are closed off by a first ring 15 and a second ring 17 respectively. The first and second rings 15, 17 form the upper end and the lower end of the spring 11, with which ends the spring 11 interacts with the pump dispenser 13. Further levels are provided between the first and second levels E1, E2. In the first embodiment according to Figures 1, 2 and 3, 8 further floors E3 to E10 are provided.In the second embodiment according to Figures 5, 6 and 7, 6 further floors E3 to E8 are provided.

[0034] According to the first embodiment, four spring struts 19 are arranged in each of the ten levels. With the exception of levels E1 and E2, two adjacent spring struts 19 diverge from an upper node 21 and converge at a lower node 23. Four spring struts 19 converge at a node 19, 21, with two spring struts 19 from two adjacent levels converging at the node. The lower node 19 of the upper level (e.g., E3) becomes the upper node of the adjacent lower level (e.g., E4). Two adjacent levels are separated by a retaining ring 25. The retaining rings 25 stabilize the spring 11 and guide it during compression in the pump dispenser 13. Two upper nodes 21 and two lower nodes 23 are located on the retaining ring 25.

[0035] At both ends of each spring strut 19, protrusions 27 are formed. When the spring 11 is maximally compressed, the protrusions 27 rest on the retaining ring 25. As a result, facing spring struts 19 of two adjacent tiers are spaced apart from each other and do not lie directly on top of each other. As a result, the function of the spring struts is not impaired by the product being pumped. Slots 29 are provided between the ends of the four spring struts 19 of a tier and the two retaining rings that define the tier. Therefore, each node 21, 23 is slotted four times (detail Figure 3).

[0036] The nodes 21, 23 of two adjacent retaining rings 25 are each offset by 90 degrees. This also means that the two upper nodes 21 and the two lower nodes 23 of a level are offset by 90 degrees. The two upper nodes 21 and the two lower nodes 23 of a level each enclose an angle of 180 degrees. In other words, the two nodes lying on a retaining ring 25 enclose an angle of 180 degrees. As the figures show, the first and second rings 15, 17 and the retaining rings have the same outer diameter and are arranged concentrically one above the other. The spring legs 19 lie or wind on the outer surface 31 of the plastic spring. In the relaxed position of the spring 11, the spring legs 19 have a pitch angle 33 of preferably 32 to 38 degrees.

[0037] As the second embodiment according to Figures 5 to 7 shows, the spring 11 can also have stages that have only two spring legs 19. These two spring legs 19 do not converge at any nodes. In Figures 5 to 7, these are stages E1, E2, E5, and E6. Stages E3, E4, E7, and E8 have four spring legs 19, as explained in the description of the first embodiment.

[0038] The plastic spring 11 is preferably made of polyetherimide (PEI), which bears the trade name IILTEM. Thanks to the choice of plastic and the special design of the spring 11, the spring can withstand up to 5,000 actuations without losing its restoring force.

[0039] 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 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.As explained in the last paragraph, the plastic spring can withstand up to 5,000 actuation cycles of the pump head 41. A valve is implemented by a first and second plastic ball 49a, 49b. The balls 49a, 49b define the conveying direction of the liquid from the container into the dispensing opening 47 and block conveyance in the opposite direction. The liquid is sucked from the container into the dispensing chamber via a suction tube 51. In the dispensing chamber 39, the plastic spring 11 comes into contact with the liquid. The humps 27 space the spring legs 19 from each other when the plastic spring 11 is in the compressed position. This prevents the liquid from interfering with the function of the spring 11. The pump dispenser 13 is constructed entirely of plastic parts, since the spring 11 and the balls 49a, 49b are also made of plastic. This allows the pump dispenser to be disposed of separately and with little effort.The laborious separation of metal parts is no longer necessary.

[0040] 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. Only the height and diameter of the dosing chamber 39 may need to be slightly adapted to the dimensions of the plastic spring 11.

[0041] Legend:

[0042] 11 plastic spring

[0043] 13 pump dispensers

[0044] E1 Top Floor

[0045] E2 Lowest floor

[0046] E3-E10 floors

[0047] 15 First Ring

[0048] 17 Second Ring

[0049] 19 struts

[0050] 21 Upper Junction

[0051] 23 Lower Junction

[0052] 25 retaining ring

[0053] 27 humps

[0054] 29 slots

[0055] 31 lateral surface

[0056] 33 pitch angle

[0057] 35 housings

[0058] 37 cap

[0059] 39 Dosing chamber

[0060] 41 Pump head

[0061] 43 Longitudinal axis

[0062] 45 pistons

[0063] 47 Donor opening

[0064] 49a, 49b First and second plastic ball

[0065] 51 intake manifold

Claims

comprising a plastic spring (11) for use in a pump dispenser (13) - a plurality of shock absorbers (19) which are arranged in several levels (E), wherein at the transition of adjacent levels (E) the shock absorbers (19) of adjacent levels (E) are connected to each other, - a first ring (15) which forms the upper end of the spring (11) and - a second ring (17) which forms the lower end of the spring (11), characterized in that two adjacent spring legs (19) of at least one level (E) diverge from an upper node (21) at the upper end of the level (E) and converge at a lower node (23) at the lower end of the level (E).

2. Plastic spring according to claim 1, characterized in that four spring legs (19) converge at a node (21, 23), wherein two spring legs (19) of two adjacent floors (E) converge at the node (21, 23).

3. Plastic spring according to claim 1 or 2, characterized in that two adjacent floors (E) are each separated by a retaining ring (25).

4. Plastic spring according to claim 3, characterized in that at least one retaining ring (25) has two nodes (21, 23) formed from four spring strut ends.

5. Plastic spring according to one of the preceding claims, characterized in that four spring legs (19) are arranged in each level (E) of the plastic spring (11).

6. Plastic spring according to one of the preceding claims, characterized in that humps (27) are formed at the ends of the four spring legs of a floor (E) in order to space the spring legs (19) apart in the compressed state.

7. Plastic spring according to one of claims 3 to 6, characterized in that slots (29) are provided between the ends of the four spring legs (19) of a level (E) and the two retaining rings (25) which define the level (E).

8. Plastic spring according to one of the preceding claims, characterized in that the plastic spring is composed of stages (E) with four spring legs (19) and with two spring legs (19).

9. Plastic spring according to one of the preceding claims, characterized in that the nodes (21, 23) of two adjacent retaining rings are arranged offset by 90 degrees.

10. Plastic spring according to one of the preceding claims, characterized in that the two nodes (21 ,23) of a retaining ring enclose an angle of 180 degrees.

11. Plastic spring according to one of claims 3 to 10, characterized in that the first and second ring (15, 17) and the retaining rings (25) have an identical outer diameter and are arranged concentrically one above the other.

12. Plastic spring according to one of the preceding claims, characterized in that the spring legs (19) extend on the outer surface (31) of the plastic spring (11).

13. Plastic spring according to one of the preceding claims, characterized in that the spring legs (19) in the relaxed position of the spring (11) have an angle of inclination between 30 and 40 degrees and preferably between 32 and 38 degrees.

14. Plastic spring according to one of the preceding claims, characterized in that the plastic spring (11) is made of a polyetherimide (PEI).

15. Pump dispenser (13) for metered dispensing 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 for performing a pump stroke, a piston (45) which is fixed to the pump head (41) and is movable in the metering chamber (39) for conveying 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 returns the pump head (41) relative to the housing (35), a suction tube (51) with which liquid is drawn from the container into the metering 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 dispenser opening (37) and prevent conveying in the reverse direction, characterized in thatthat 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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