WO2023161399A1

WO2023161399A1 - Plastic spring

Info

Publication number: WO2023161399A1
Application number: PCT/EP2023/054647
Authority: WO
Inventors: Sree Hari R. NAIR; Sunil KUMAR SHARMA
Original assignee: Alpla Werke Alwin Lehner Gmbh & Co. Kg
Priority date: 2022-02-24
Filing date: 2023-02-24
Publication date: 2023-08-31

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

plastic spring

field of invention

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.

State of the art

Pump dispensers are used to remove a liquid, which can also have an increased viscosity (creams or gels), from a storage container by pressing a dispenser head down. The dispenser extension is formed on the dispenser head and therefore moves with the dispenser head. A metal spring is integrated into the dispenser to reset the dispenser head. The valve function, which is necessary so that the liquid is pumped into the dispenser extension when the head is pressed and liquid is sucked into the pump dispenser when the head is reset, is realized by metal or glass balls.

Sorted disposal of such pump dispensers known from the prior 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. Also, having the donor appendage move with the head is impractical, as this often causes fluid to miss its target (e.g., a user's hand) and contaminate the area surrounding the target.

There are already pump dispensers with plastic balls with a valve function and plastic springs with an adapted design. The pump dispenser must be adapted to the plastic spring so that the plastic spring works reliably and has good long-term resilience. This involves considerable effort, since a pump dispenser has to be specially developed and produced for the plastic spring.

object of the invention

The disadvantages of the prior art described result in the task of creating a plastic spring which does not entail complex and correspondingly expensive adaptation of the pump dispenser and which can withstand a large number of actuation cycles of the pump dispenser. Description

The solution to the problem is achieved with a plastic spring for use in a pump dispenser through the features listed in the characterizing section of patent claim 1. Further developments and/or advantageous embodiment variants are the subject matter of the dependent patent claims.

The invention is preferably characterized in that two adjacent spring legs of at least one floor diverge from an upper node at the upper end of the floor and converge at a lower node at the lower end of the floor. The provision of the nodal points gives the spring permanent stability and restoring force and consequently endures up to 5000 actuation cycles. In addition, the nodes ensure that the spring expands only minimally in the radial direction when compressed. 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.

In a particularly preferred embodiment of the invention, four spring struts come together at a node, with two spring struts of two adjacent floors each coming together at the node. As a result, each node is reinforced, giving the plastic spring more stability and having almost identical properties to a spring made of spring steel.

It proves to be advantageous if two adjacent floors are each separated by a retaining ring. The retaining rings contribute to the further stability and durability of the spring. For example, they help to ensure that the spring does not buckle from the vertical in the compressed position and that the spring struts can rest on adjacent retaining rings in the compressed position

In a further particularly preferred embodiment of the invention, four spring struts are arranged on each floor of the plastic spring. As a result, a particularly stable plastic spring with an increased restoring force can be implemented.

It has proven to be expedient if humps are formed at the ends of the four spring struts of one floor in order to space the spring struts in the compressed state. Since the spring or spring legs come into contact with the product to be pumped in the dosing chamber, the distance between the bumps prevents the product from sticking to the spring legs or otherwise impeding them. It is advantageous if opposing humps rest on the retaining ring in between, since the retaining ring prevents the humps from evading or slipping off one another. Slots are expediently provided between the ends of the four spring legs of a floor and the two retaining rings which delimit the floor. The slots allow the spring ends to move more flexibly as the spring compresses.

In a further preferred embodiment of the invention, the plastic spring consists of floors with four spring legs and two spring legs. The different tiers can be put together as you like to form the spring. As a result, the restoring force of the spring can be precisely adjusted to the requirements of the pump dispenser.

It proves to be advantageous if the nodes of two adjacent retaining rings are each offset by 90 degrees. This gives the spring a symmetrical and stable structure.

It also proves to be advantageous if the two nodal points of a retaining ring enclose an angle of 180 degrees, as a result of which the stability of the spring is improved even further.

Due to the fact that the first and second rings and the retaining rings have an identical outer diameter and are arranged concentrically one above the other, the spring has the outer dimensions of a rotary cylinder with an outer surface. This makes it easier to integrate the spring into a standard pump dispenser.

It is advantageous if the struts extend on the outer surface of the plastic spring. As a result, the spring struts do not protrude from the lateral surface. The spring struts preferably remain on the lateral surface even in the compressed position, and the outer diameter of the spring remains essentially unchanged.

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 when the spring is in the relaxed position. This gives the spring a compression ratio (the ratio of the lengths of the spring in the unloaded position and in the compressed position) which corresponds to a standard steel spring.

The invention is also preferably characterized in that the plastic spring is made from 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 the spring to be used for up to 5000 operating cycles 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 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 dosing chamber of a previously known and accordingly commercially available pump dispenser. With such a pump dispenser, all components are made of plastic. Accordingly, the pump dispenser can be disposed of by type and fed into a recycling loop without any effort. Further advantages and features emerge from the following description of an exemplary embodiment of the invention with reference to the schematic illustrations. It shows in a representation that is not true to scale:

Figure 1: a plastic spring in a first embodiment and in a

side view;

FIG. 2: a sectional view of the spring from FIG. 1 along section line II-II;

FIG. 3: an enlarged view of detail III from FIG. 1;

FIG. 4: an isometric view of the spring from FIG. 1;

Figure 5: the plastic spring in a second embodiment and in a

side view;

FIG. 6: a sectional illustration of the spring from FIG. 5 along the cutting line

VI-VI;

FIG. 7: an isometric view of the spring from FIG. 5 and

FIG. 8: a sectional view of a pump dispenser in which the plastic spring is installed. A plastic spring is shown in FIGS. The plastic spring is intended to be incorporated into a pump dispenser 13 as shown in FIG. The plastic spring 11 comes into contact with the product to be pumped. The plastic spring 11 is divided into several floors E. The top floor E1 and the bottom floor 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, respectively, with which ends the spring 11 interacts with the pump dispenser 13. Additional floors are provided between the first and second floors E1, E2. In the first exemplary embodiment according to FIGS. 1, 2 and 3, 8 further levels E3 to E10 are provided. In the second exemplary embodiment according to FIGS. 5, 6 and 7, 6 further floors E3 to E8 are provided.

According to the first exemplary embodiment, four spring struts 19 are arranged in each of the ten floors. With the exception of floors E1 and E2, two adjacent struts 19 diverge from an upper node 21 and converge at a lower node 23. At a node 19,21 four struts 19 converge, with two struts 19 of two adjacent floors converge to the node. The lower node 19 of the upper level (e.g. E3) thereby becomes the upper node of the adjacent lower level (e.g. E4). Two adjacent floors 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. There are two upper nodes 21 and two lower nodes 23 on the retaining ring 25.

At both ends of each strut 19 humps 27 are formed. When the spring 11 is maximally compressed, the bumps 27 rest on the retaining ring 25 . As a result, mutually facing spring legs 19 of two adjacent levels are spaced apart and are not directly one above the other. As a result, the function of the spring struts is not impaired by the product to be pumped. Slots 29 are provided between the ends of the four spring legs 19 of a floor and the two retaining rings which delimit the floor. Each node 21, 23 is therefore slotted four times (detail in FIG. 3).

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 floor are offset by 90 degrees. The two upper nodes 21 and the two lower nodes 23 of a floor each enclose an angle of 180 degrees. Described differently, the two nodes, which lie on a retaining ring 25, enclose an angle of 180 degrees. As the figures show, the first and second ring 15,17 and the retaining rings have the same outer diameter and are arranged concentrically one above the other. The struts 19 lie or wind on the lateral 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.

As the second exemplary embodiment according to FIGS. 5 to 7 shows, the spring 11 can also have tiers which only have two spring legs 19 . These two struts 19 do not converge at any nodes. In the figures 5 to 7 are the floors E1, E2, E5 and E6. Floors E3, E4, E7 and E8 have four struts 19, as explained in the description of the first embodiment.

The plastic spring 11 is preferably made of a polyetherimide (PEI) which bears the trade name IILTEM. Due to the choice of plastic and the special design of the spring 11, the spring can withstand up to 5000 actuations without losing its restoring force.

The spring 11 is integrated into a pump dispenser 13 in FIG. The pump dispenser has a housing 35 which is held with a cap 37 on a container. It 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 includes 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 first and second positions for performing a pump stroke. A piston 45 which is fixed to the pump head 41 is movable in the metering chamber 39 to deliver the liquid. A dispensing port 47 is connected to the metering chamber 39 . The metered liquid can leave the pump dispenser 13 through the dispenser opening 47 . The plastic spring 11 resets the pump head 41 relative to the housing 35 . As explained in the last paragraph, the plastic spring endures up to 5000 actuation cycles of the pump head 41. A valve is implemented in FIG. 1 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 reverse direction. The liquid is sucked out of the container into the dosing chamber via a suction pipe 51 . In the dosing chamber 39, the plastic spring 11 comes into contact with the liquid. The spring legs 19 are spaced apart from one another in the compressed position of the plastic spring 11 by the humps 27 . As a result, the liquid cannot have a disruptive effect on 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. As a result, the pump dispenser can be disposed of separately with little effort. The laborious separation of metal parts is no longer necessary.

The plastic spring 11 has the further advantage that it is designed in such a way that it can be integrated into a commercially available pump dispenser 13 . The pump dispenser 13 can therefore be adopted from mass production. Only the height and the diameter of the dosing chamber 39 may have to be adjusted slightly to the dimensions of the plastic spring 11 .

Legend:

11 plastic spring

13 pump dispensers

E1 Top Floor

E2 lowest floor

E3-E10 floors

15 First ring

17 Second ring

19 struts

21 Upper Node

23 Lower Node

25 retaining ring

27 cusp

29 slots

31 lateral surface

33 pitch angles

35 housing

37 cap

39 dosing chamber

41 pump head

43 longitudinal axis

45 pistons

47 dispenser opening

49a, 49b First and second plastic balls

51 intake manifold

Claims

Having a plastic spring (11) for use in a pump dispenser (13).

- a plurality of spring struts (19) which are arranged in several floors (E), the spring struts (19) of adjacent floors (E) being connected to one another at the transition between adjacent floors (E),

- a first ring (15) forming the upper end of the spring (11) and

- a second ring (17) forming the lower end of the spring (11), characterized in that two adjacent struts (19) of at least one floor (E) consist of an upper node (21) at the top of the floor (E) diverge and converge at a lower node (23) at the bottom of the tier (E).

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

3. Plastic spring according to claim 1 or 2, characterized in that two adjacent tiers (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 leg ends.

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

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) 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 floor (E) and the two retaining rings (25) which delimit the floor (E). are.

8. Plastic spring according to one of the preceding claims, characterized in that the plastic spring consists of tiers (E) with four spring legs (19) and 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 each 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 a pitch angle 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 removal of a liquid from a container onto which the pump dispenser (13) can be placed, having a housing (35) which is held on the container with a cap (37) and in which a dosing chamber (39 ) is formed, a pump head (41) movable up and down relative to the housing (35) along the longitudinal axis (43) of the dispenser (13) between first and second positions to perform a pump stroke, a piston (45) mounted on the pump head (41) is fixed and can be moved in the metering chamber (39) to deliver 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 is sucked 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 dispensing opening (37) and block conveyance in the reverse 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.