Elastic reset mechanism and press pump comprising same

Abstract

An elastic reset mechanism for a press pump. The elastic reset mechanism (140) is made of plastic, and comprises at least one elastic element. The elastic element comprises at least a first elastic unit (143) and a second elastic unit (144) arranged from top to bottom, wherein the first elastic unit (143) is located at the top and has an upper end and a lower end; the second elastic unit (144) is located at the bottom and has an upper end and a lower end; and the first elastic unit (143) and the second elastic unit (144) are arranged in such a manner that the lower end of the first elastic unit (143) is located below the upper end of the second elastic unit (144), such that the sum of the axial height of the first elastic unit (143) and the axial height of the second elastic unit (144) is greater than the axial height of the elastic reset mechanism (140). By means of the elastic reset mechanism having such a structure, the elastic reset mechanism is allowed to have a smaller size to obtain a larger elastic force, thereby facilitating a reduction in the overall size of the press pump.

Description

Elastic return mechanism and press pump comprising same TECHNICAL FIELD

[0001] The present application relates to the field of packaging of liquid or semi-liquid products, and in particular to a press pump for dispensing a product from a container, and more particularly to a structural improvement of an elastic return mechanism in the press pump. BACKGROUND

[0002] Press pumps are widely used in the packaging of daily-use products, pharmaceuticals and the like, for pumping the products from a container to the outside for use by a consumer.

[0003] An elastic return mechanism, such as a spring, is included in a press pump to return the press pump to its original position after the press pump is pressed downward to pump the product from the container. A metal spring is conventionally used in a press pump. However, with the increasingly stringent environmental standards, it is necessary to make the press pump fully plastic, in which the metal spring is mainly replaced by a plastic supported elastic return mechanism, which allows the used press pump to be more conveniently recycled for subsequent reuse and recycling.

[0004] At present, many plastic elastic return mechanisms (or plastic springs) of various shapes and structures have been proposed, and these elastic return mechanisms have different properties. Some of them have good elasticity, while others have insufficient elasticity. However, a common problem with the existing plastic elastic return mechanisms is that, compared with a metal spring, the plastic spring needs to have significantly increased dimensions, including diameter, thickness, length, etc., in order to obtain the same elasticity. Corresponding to the increased dimensions of the plastic spring, the volume of the press pump also needs to be increased in order to reserve sufficient space for the plastic spring. In this way, the material used to manufacture the press pump is increased, thereby increasing the manufacturing cost of the press pump.

[0005] For example, in order to increase the elasticity of the plastic elastic return mechanism, one method is to increase the length of the elastic return mechanism. In this case, in order to have sufficient space in the press pump to accommodate the elastic return mechanism, the length of the cylinder, the piston rod and other components of the press pump also needs to be correspondingly lengthened. This will require more material to manufacture the press pump.

[0006] In addition, increasing the size of the press pump to accommodate the dimensions of the elastic return mechanism will make the press pump occupy more space in the product container, thereby resulting in a decrease in the amount of product that can be contained in the container.

[0007] In view of the above problems of the press pump with a plastic elastic return mechanism in the prior art, there is a need in the art to further improve the structure of the press pump to overcome the technical problems existing in the existing press pump. SUMMARY

[0008] The present application is made to solve the problems existing in the prior art as described above. The object of the present application is to provide an elastic return mechanism for a press pump, which is made of plastic and can obtain a required elastic force with a small size, such as overall height, thereby helping to reduce the overall size of the press pump.

[0009] The present application provides an elastic return mechanism for a press pump, which is preferably made of plastic and comprises at least one elastic element. The elastic element comprises at least a first elastic unit and a second elastic unit arranged from top to bottom, the first elastic unit being located at the upper part and having an upper end and a lower end, and the second elastic unit being located at the lower part and having an upper end and a lower end, wherein the first elastic unit and the second elastic unit are arranged such that the lower end of the first elastic unit is located below the upper end of the second elastic unit, so that the sum of the axial height of the first elastic unit and the axial height of the second elastic unit is greater than the axial height of the elastic return mechanism.

[0010] With the above structure, the elastic return mechanism is allowed to have a small size, such as a small overall height, while a large overall deformation and thus a large elastic force can be generated by the staggered arrangement of the first and second elastic units. The reduction in size of the elastic return mechanism can further help to reduce the overall size of the press pump.

[0011] Specifically, the first elastic unit and the second elastic unit can be in the form of elastic strips or elastic sheets.

[0012] Preferably, the first elastic unit and the second elastic unit are formed as arc-shaped elastic strips.

[0013] In a specific example, the axial height of the first elastic unit is equal to the axial height of the second elastic unit. The axial height of the first elastic unit and the axial height of the second elastic unit are defined as the distance from the upper end to the lower end of each of them. Of course, the axial height of the first elastic unit and the axial height of the second elastic element can also be different.

[0014] Preferably, the elastic return mechanism further comprises at least one of the following structures:

[0015] an upper ring, the upper end of the first elastic unit being connected to the upper ring;

[0016] a lower ring, the lower end of the second elastic unit being connected to the lower ring; and

[0017] a connecting section, the lower end of the first elastic unit and the upper end of the second elastic unit being connected by the connecting section.

[0018] The connecting section can be linear or curved.

[0019] Preferably, a hinge part is provided at least one of the upper end between the upper ring and the first elastic unit and the lower end between the lower ring and the lower end of the second elastic unit. The hinge part can allow the first elastic unit and the second elastic unit to bend more easily.

[0020] The present application also relates to a press pump comprising a movable part and a fixed part, the movable part being able to reciprocate between an upper stroke end and a lower stroke end relative to the fixed part, characterized in that the press pump comprises an elastic return mechanism as described above, the elastic return mechanism being supported between the movable part and the fixed part.

[0021] In a specific structure, the movable part comprises a pressure head and a piston rod connected below the pressure head, and the fixed part comprises a socket and a cylinder connected with the socket. The piston rod extends into the cylinder, and a piston is arranged on the end of the piston rod extending into the cylinder away from the pressure head, the outer circle of the piston being in interference fit with the inner wall of the cylinder. The upper end of the elastic return mechanism is supported on the pressure head or the piston rod, and the lower end of the elastic return mechanism is supported on the socket or a shoulder part in the inner wall of the cylinder.

[0022] Preferably, at least one guide block is further arranged on the elastic return mechanism, and a guide groove is formed on the inner wall of the cylinder, the guide block being able to fit in the guide groove. The arrangement of the guide block and the guide groove helps prevent the elastic return mechanism from being twisted when it is pressed.

[0023] Preferably, the elastic return mechanism comprises a support mechanism, the support mechanism being located radially inside the elastic return mechanism and being axially slidably abutted on the outer surface of the piston rod when the elastic return mechanism is sleeved on the piston rod. The support mechanism helps prevent the guide block from being detached from the guide groove when the press is pressed.

[0024] Preferably, a helical rib is formed on the outer surface of the piston rod, and the support mechanism is arranged to be positionally offset from the helical rib when sleeved on the piston rod, so as to avoid interference between the support mechanism and the helical rib when the press is pressed.

[0025] Preferably, a cylinder plug is integrally formed on the lower part of the elastic return mechanism.

[0026] Preferably, a hollow part is formed on the circumferential wall of the cylinder, the hollow part being positionally corresponding to the position of the elastic element, so as to allow the elastic element to partially extend out of the cylinder through the hollow part when the elastic return mechanism is pressed to deform the elastic element. In this way, greater deformation of the elastic element can be obtained, thereby helping to obtain greater elastic force. On the other hand, under the premise of obtaining the same elastic force, the elastic return mechanism can be made smaller, thereby helping to reduce the overall size of the press pump.

[0027] As an alternative or in addition to the above-mentioned support mechanism, the elastic return mechanism can further comprise a sliding ring located radially inward of the elastic return mechanism, the inner side of the guide block being connected to the sliding ring, and when the elastic return mechanism is sleeved on the piston rod, the sliding ring is sleeved on the piston rod in a slidable manner. BRIEF DESCRIPTION OF DRAWINGS

[0028] The features and advantages of the present application will become more apparent from the detailed description in conjunction with the accompanying drawings. In the drawings:

[0029] Fig. 1 shows a front view of a press pump according to a first embodiment of the present application.

[0030] Fig. 2 shows a sectional view of the press pump of Fig. 1.

[0031] Fig. 3 shows a front view of an elastic return mechanism in the press pump of Fig. 1.

[0032] Fig. 4 shows a sectional view of the elastic return mechanism taken along line A-A in Fig. 3.

[0033] Fig. 5 shows a perspective view of the elastic return mechanism.

[0034] Fig. 6 shows a schematic sectional view of the elastic return mechanism being depressed.

[0035] Fig. 7 shows a front view of an elastic return mechanism according to a second embodiment.

[0036] Fig. 8 shows a sectional view of the elastic return mechanism taken along line B-B in Fig. 7.

[0037] Fig. 9 shows a top perspective view of a cylinder according to the second embodiment.

[0038] Fig. 10 shows a bottom perspective view of the cylinder of Fig. 9.

[0039] Fig. 11 shows a sectional view of a state in which the elastic return mechanism according to the second embodiment is sleeved on a piston rod.

[0040] Fig. 12 shows a perspective view of a state in which the elastic return mechanism according to the second embodiment is sleeved on a piston rod.

[0041] Fig. 13 shows a front view of a state in which the elastic return mechanism according to the second embodiment is sleeved on a piston rod.

[0042] Fig. 14 shows a front view of an elastic return mechanism according to a third embodiment of the present application.

[0043] Fig. 15 shows a bottom perspective view of the elastic return mechanism of Fig. 14.

[0044] (Symbol explanation) 100 Pressing pump 110 Head 120 Mouthpiece 130 Cylinder 140 Elastic return mechanism 141 Upper ring 142 Lower ring 143 First elastic unit 144 Second elastic unit 145 Connecting section 146 Hinge section 111 Piston rod 112 Piston 211 Piston rod 212 Spiral convex rib 240 Elastic return mechanism 241 First elastic unit 242 Second elastic unit 243 Guide block 250 Support mechanism 230 Cylinder 231 Guide groove 232 Hollowed section 233 Cylinder plug 340 Elastic return mechanism 341 First elastic unit 342 Second elastic unit 343 Guide block 344 Sliding ring DETAILED DESCRIPTION

[0045] The specific embodiments of the present application will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments shown in the drawings are merely preferred embodiments of the present application, and do not constitute a limitation on the scope of the present application. Those skilled in the art can make various modifications, variations, equivalent replacements to the embodiments shown in the drawings on the basis of the embodiments, and the technical features described in the following different embodiments can be combined with each other arbitrarily without contradiction, which all fall within the protection scope of the present application.

[0046] In the following detailed description, the terms such as "upper" and "lower" used to indicate the orientation are with reference to the orientation of the pressing pump shown in the drawings, so as to facilitate the description. The orientation is also basically the orientation taken by the pressing pump when it is usually operated, and in other cases, for example, in the transportation, storage, etc. of the product, the orientation of the pressing pump can be changed.

[0047] <First embodiment>

[0048] Figs. 1 to 6 show the schematic views of the pressing pump 100 of the first embodiment of the present application and its components.

[0049] Fig. 1 shows the front view of the pressing pump 100 of the first embodiment, and Fig. 2 shows the sectional view of the pressing pump 100. The pressing pump 100 comprises a head 110, and a piston rod 111 connected below the head 110. The pressing pump 100 further comprises a mouthpiece 120 and a cylinder 130, and the mouthpiece 120 and the cylinder 130 are connected together. The mouthpiece 120 has connecting structures such as internal threads on the inner surface of the outer sleeve, which can be matched with the matching structures on the container (not shown) to connect the pressing pump 100 to the container.

[0050] A piston 112 is provided on the end of the piston rod 111 distal from the pressure head 110 (the free end), and the outer circumference of the piston 112 is in interference fit with the inner surface of the cylinder 130. In this way, when the pressure head 110 is pressed down, the space in the cylinder 130 containing the product (i.e. the space below the piston 112) decreases, causing the pressure therein to rise, thereby pumping the product in the cylinder 130 out through the spout of the pressure head 110.

[0051] The press pump 100 further comprises a resilient return mechanism 140, which can be made of plastic, and which is supported at one end on the movable part of the press pump 100 (including the pressure head 110, the piston rod 111, etc.) and at the other end on the fixed part of the press pump 100 (including the holder 120, the cylinder 130, etc.). In this way, the resilient return mechanism 140 exerts a biasing force on the pressure head 110 towards its upper end of travel.

[0052] After the pressure applied to the pressure head 110 is removed, the resilient force of the resilient return mechanism 140 causes the pressure head 110 and the piston rod 111 connected thereto to move upwards towards their upper end of travel. In the process, the pressure in the cylinder 130 decreases, creating a negative pressure which draws the product in the container into the cylinder 130 for the next dispensing.

[0053] Figures 3 to 5 show a cross-sectional view, an elevation view and a perspective view of the resilient return mechanism 140 in the press pump 100, respectively. The resilient return mechanism 140 (in one embodiment a plastic spring) comprises an upper ring 141, a lower ring 142 and a number of resilient elements extending between the upper ring 141 and the lower ring 142. One of the upper ring 141 and the lower ring 142 is supported on the movable part of the press pump 100, e.g. in the exemplary preferred structure shown in the figures, specifically the upper ring 141 is supported on the pressure head 110. The other of the upper ring 141 and the lower ring 142 is supported on the fixed part of the press pump 100, e.g. in the exemplary preferred structure shown in the figures, specifically the lower ring 142 is supported on a shoulder on the inner surface of the cylinder 130.

[0054] In the elastic return mechanism 140 of the press pump 100 of the present application, each elastic element includes at least two elastic units arranged in the up-and-down direction. In the preferred structure shown in the drawings, each elastic unit includes a first elastic unit 143 located at the upper portion and a second elastic unit 144 located at the lower portion. The first elastic unit 143 has an upper end and a lower end, and the upper end of the first elastic unit 143 is connected to the upper ring 141. The second elastic unit 144 also has an upper end and a lower end, and the lower end of the second elastic unit 144 is connected to the lower ring 142. As shown in the drawings, the first elastic unit 143 and the second elastic unit 144 of the elastic element are arranged alternately, i.e., the lower end of the first elastic unit 143 is located below the upper end of the second elastic unit 144. In other words, as viewed in the direction perpendicular to the axial direction of the elastic return mechanism 140, the first elastic unit 143 and the second elastic unit 144 partially overlap each other.

[0055] The first elastic unit 143 and the second elastic unit 144 may, for example, be in the form of elastic strips, elastic pieces, or the like.

[0056] Further, the lower end of the first elastic unit 143 and the upper end of the second elastic unit 144 are connected together by a connecting section 145.

[0057] In the preferred structure shown in the drawings, the first elastic unit 143 and the second elastic unit 144 are substantially arcuate, and the bending directions of the arcs of the first elastic unit 143 and the second elastic unit 144 are opposite to each other. The connecting section 145 is preferably a straight section. However, the connecting section 145 can also be formed as a curved section, which is also within the scope of the present application.

[0058] As shown in Fig. 4, let the axial height of the first elastic unit 143 from its upper end to its lower end be Ll, the axial height of the second elastic unit 144 from its upper end to its lower end be L2, and the axial height of the connecting section 145 (or the distance from the lower end of the first elastic unit 143 to the upper end of the second elastic unit 144) be Hl, then the distance between the upper end of the first elastic unit 143 and the lower end of the second elastic unit 144, or the axial height of the elastic return mechanism 140, is smaller than the sum of the axial height Ll and the axial height L2. Fig. 6 schematically shows that the elastic return mechanism 140 can be compressed to a height H2 after being pressed.

[0059] In this way, the elastic return mechanism 140 can achieve a larger deformation with a smaller overall size, thereby obtaining a larger elastic return force.

[0060] In the preferred structure, the upper end of the first elastic unit 143 is connected to the upper ring 141 by a hinge portion 146, and the lower end of the second elastic unit 144 can also be connected to the lower ring 142 by the hinge portion 146. The hinge portion 146 may, for example, be in the form of a thin wall.

[0061] In the preferred structure shown in the figures, the axial heights Ll and L2 of the first and second elastic units 143 and 144 are substantially equal. However, the axial heights of the first and second elastic units 143 and 144 can also be different, which is also within the scope of the present application.

[0062] [Second Embodiment]

[0063] Figs. 7 to 13 show a second embodiment of the present application, in which the elastic return mechanism 240 and the air cylinder 230 and the piston rod 211 cooperating therewith in the second embodiment are specifically shown. Unless otherwise stated or obviously contradictory, the technical features described above in the first embodiment are also applicable to the second embodiment, and vice versa. Here, the technical features identical to those in the first embodiment will not be described in detail, and only the technical features not mentioned in the first embodiment will be disclosed in detail.

[0064] Fig. 7 shows a front view of the elastic return mechanism 240 of the second embodiment, and Fig. 8 shows a sectional view of the elastic return mechanism 240.

[0065] The elastic return mechanism 240 has a plurality of elastic elements, each of which includes at least two elastic units arranged in the up-down direction, i.e., a first elastic unit 241 located above and a second elastic unit 242 located below. The first and second elastic units 241 and 242 are also staggered, i.e., the lower end of the first elastic unit 241 is below the upper end of the second elastic unit 242.

[0066] In the second embodiment, the elastic return mechanism 240 is provided with a guide block 243. Correspondingly, a guide groove 231 extending along the longitudinal direction of the air cylinder 230 is formed on the inner wall of the air cylinder 230. The guide block 243 can be fitted in the guide groove 231 (see Fig. 9). When the elastic return mechanism 240 is pressed, the guide block 243 and the guide groove 231 cooperate to guide the deformation of the elastic return mechanism 240.

[0067] In addition, a hollow portion 232 is formed on the circumferential wall of the air cylinder 230, which corresponds to the position of the elastic elements of the elastic return mechanism 240. When the elastic return mechanism 240 is pressed and the elastic elements are deformed, the elastic elements can partially extend out of the air cylinder through the hollow portion 232, thereby allowing the elastic elements to have a larger deformation amount.

[0068] As an additional or alternative structure to the connecting section 145 in the first embodiment, a support mechanism 250 is connected between the lower end of the first elastic unit 241 and the upper end of the second elastic unit 242. The support mechanism 250 is provided on the inner side of the elastic return mechanism 240, and when the elastic return mechanism 240 is fitted on the piston rod 211, the support mechanism 250 can be axially slidably abutted on the outer surface of the piston rod 211, as can be seen from Figs. 11 to 13.

[0069] The support mechanism 250 can be, for example, in the shape of a cross as shown in the figures, whereby the support mechanism 250 can have a greater structural strength.

[0070] It is also shown in Figs. 12 and 13 that a helical rib 212 is formed on the piston rod 211, which can be used to guide the upper ring of the elastic return mechanism 240. Also, the elastic return mechanism 240 is arranged such that its support mechanism 250 is offset from the position of the helical rib 212 when it is fitted on the piston rod 211. Thereby, mutual interference between the support mechanism 250 and the helical rib 212 during operation is avoided.

[0071] In the preferred structure shown in the figures, a guide block 243 is provided on the lower end of the first elastic unit 241 and on the upper end of the second elastic unit 242, respectively.

[0072] In the second embodiment, as shown in Figs. 7 and 8, a guide groove 231 is integrally formed on the lower end of the elastic return mechanism 240 as an alternative structure to the lower ring 142 of the first embodiment.

[0073] Preferably, as shown in the figures, a cylinder plug 233 is integrally formed on the lower part of the elastic return mechanism 240. The cylinder plug 233 can be formed on the lower ring, or can be an alternative structure to the lower ring.

[0074] <Third Embodiment>

[0075] Figs. 14 and 15 show the elastic return mechanism 340 of the third embodiment of the present application. As there is no contrary statement or obvious contradiction, the technical features described above in the first and second embodiments also apply to the third embodiment, and vice versa. Here, the same technical features as in the first and second embodiments will not be described in detail, and only the technical features not mentioned in the first and second embodiments will be disclosed in detail.

[0076] As in the first and second embodiments, the elastic return mechanism 340 of the third embodiment comprises an upper first elastic unit 341 and a lower second elastic unit 342, the lower end of the first elastic unit 341 being below the upper end of the second elastic unit 342. A guide block 343 is connected between the lower end of the first elastic unit 341 and the upper end of the second elastic unit 342.

[0077] In the third embodiment, a sliding ring 344 is provided inside the elastic reset mechanism 340, and the inner part of the guide block 343 is connected to the sliding ring 344. The sliding ring 344 is sleeved on the piston rod and can reciprocate along the piston rod in the up-down direction.

[0078] By setting the sliding ring 344, radial outward support can be provided for the guide block 343, that is, it can prevent the guide block 343 from moving radially inward toward the piston rod during the pressing process, causing the guide block 343 to slide out of the guide groove in the cylinder.

[0079] Therefore, it can be seen that the sliding ring 344 in the third embodiment plays a similar role to the support mechanism 250 in the second embodiment. In other words, the two can serve as substitutes or complements for each other.

Claims

1. An elastic return mechanism provided in a press pump, the elastic return mechanism comprising at least one elastic element, characterized in that, The elastic element comprises at least a first elastic unit and a second elastic unit arranged from top to bottom, the first elastic unit is located at the upper part and has an upper end and a lower end, the second elastic unit is located at the lower part and has an upper end and a lower end, wherein the first elastic unit and the second elastic unit are arranged such that the lower end of the first elastic unit is located below the upper end of the second elastic unit, so that the sum of the axial height of the first elastic unit and the axial height of the second elastic unit is greater than the axial height of the elastic return mechanism.

2. The elastic return mechanism of claim 1, wherein, The first elastic unit and the second elastic unit are formed as elastic strips or elastic sheets.

3. The elastic return mechanism of claim 2, wherein, The first elastic unit and the second elastic unit are formed as arc-shaped elastic strips.

4. The elastic return mechanism of claim 1, wherein, The axial height of the first elastic unit is equal to the axial height of the second elastic unit.

5. The elastic return mechanism of any one of claims 1 to 4, wherein, The elastic return mechanism further comprises at least one of the following structures: an upper ring, the upper end of the first elastic unit is connected to the upper ring; a lower ring, the lower end of the second elastic unit is connected to the lower ring; and a connecting section, the lower end of the first elastic unit and the upper end of the second elastic unit are connected through the connecting section.

6. The elastic return mechanism of claim 5, wherein, A hinge part is arranged at least one of the upper end between the upper ring and the first elastic unit and the lower end between the lower ring and the second elastic unit.

7. A squeeze pump comprising a movable part and a fixed part, the movable part being reciprocable relative to the fixed part between upper and lower stroke dead centres, characterised in that, The press pump comprises the elastic return mechanism as claimed in any one of claims 1-6, and the elastic return mechanism is supported between the movable part and the fixed part.

8. The press pump as claimed in claim 7, wherein the movable part comprises a pressure head and a piston rod connected below the pressure head, the fixed part comprises a tooth socket and a cylinder connected to the tooth socket, wherein the piston rod extends into the cylinder, and an end of the piston rod away from the pressure head and extending into the cylinder is provided with a piston, and the outer circle of the piston is in interference fit with the inner wall of the cylinder; wherein the upper end of the elastic return mechanism is supported on the pressure head or the piston rod, and the lower end of the elastic return mechanism is supported on the tooth socket or a shoulder part in the inner wall of the cylinder.

9. The squeeze pump of claim 8, wherein At least one guide block is further arranged on the elastic return mechanism, and a guide groove is formed on the inner wall of the cylinder, and the guide block can be fitted in the guide groove.

10. The squeeze pump of claim 9, wherein The elastic return mechanism comprises a support mechanism located at the radially inner side of the elastic return mechanism, and when the elastic return mechanism is sleeved on the piston rod, the support mechanism is axially slidably abutted on the outer surface of the piston rod.

11. The squeeze pump of claim 10, wherein A helical rib is formed on the outer surface of the piston rod, and the support mechanism is arranged to be positionally offset from the helical rib when sleeved on the piston rod.

12. The squeeze pump of claim 8, wherein A cylinder plug is integrally formed at the lower part of the elastic return mechanism.

13. The push pump as claimed in claim 8, characterized in that, A hollow part is formed on the circumferential wall of the cylinder, and the position of the hollow part corresponds to the position of the elastic element, so that when the elastic return mechanism is pressed and the elastic element is deformed, the elastic element is allowed to partially extend out of the cylinder through the hollow part.

14. The squeeze pump of claim 9, wherein The elastic reset mechanism comprises a sliding ring, which is located at the radially inner side of the elastic reset mechanism, the inner side of the guide block is connected to the sliding ring, and when the elastic reset mechanism is sleeved on the piston rod, the sliding ring is slidably sleeved on the piston rod.

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