Elastic member and pump assembly including the same

1. A pump assembly comprising:

an elastic member comprising:

a first support;

a second support; and

a connection part connecting the first support and the second support and comprising a plurality of peaks and valleys alternatingly disposed in an outward direction,

wherein the plurality of peaks and valleys are configured to be bent when the elastic member is pressurized;

a sealing part accommodating the elastic member; and

a stem coupled to a piston rod and configured to ascend and descend together with the piston rod,

wherein the elastic member is disposed between the stem and the sealing part and is configured to provide an elastic force to the stem from the sealing part,

wherein a blade part is defined in the stem configured to restrain an upper end of the elastic member and comprises at least one air path configured to release compression and expansion of inner air generated during compression and decompression of the elastic member.

2. The pump assembly of claim 1 , wherein the elastic member is configured to be accommodated in the pump assembly in a partially compressed state.

3. The pump assembly of claim 1 , wherein the elastic member is formed of at least one among polyetheretherketone (PEEK), polycarbonate (PC), polyoxymethylene (POM), polyketone (POK), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene (PE), polyoxypropylene (POP), a polyolefin elastomer (POE), and ethylene octene/butene copolymers.

4. The pump assembly of claim 1 , wherein sizes of each of the plurality of peaks and valleys increase in a longitudinal direction.

5. The pump assembly of claim 1 , wherein the connection part is a bellows type,

wherein the connection part is defined along a circumference of the elastic member, and

wherein a circumferential surface of the connection part is sealed.

6. The pump assembly of claim 1 , wherein the second support has a two-step structure,

wherein the two-step structure has a first step structure and a second step structure,

wherein the first step structure is defined on a distal portion of the two-step structure and has a first-outer-side-wall and a first-inner-side-wall, and

wherein the second step structure is defined on a closer portion of the two-step structure and has a second-outer-side-wall and a second-inner-side-wall.

7. The pump assembly of claim 6 , wherein each step of the two-step structure comprises a step-through-hole having a buffer space inside the first step structure, and the second step structure is inwardly bent to the buffer space when the elastic force is horizontally or vertically pressured.

8. The pump assembly of claim 6 , wherein a diameter of the first-outer-side-wall of the first step structure is greater than a diameter of a peak of the plurality of peaks and valleys.

9. The pump assembly of claim 8 , wherein a horizontal margin is created by a difference between the diameter of the first-outer-side-wall of the first step structure and the diameter of the peak of the plurality of peaks and valleys, and

wherein the connection part is compressed or decompressed without interference of other components of the pump assembly by being compressed or decompressed in the horizontal margin.

10. The pump assembly of claim 6 , wherein a distance from the first-outer-side-wall of the first step structure to the first-inner-side-wall of the second step structure is greater than a height of the two-step structure.

11. The pump assembly of claim 6 , wherein a distance from the first-outer-side-wall to the first-inner-side-wall of the first step structure is greater than a height of the first step structure.

12. The pump assembly of claim 1 , wherein the second support has a multi-step structure, wherein each step of the multi-step structure has an inner side wall and an outer side wall, and a diameter of each step of the multi-step structure increases towards a distal portion of the elastic member, and

wherein the elastic member has a through hole penetrating the first support, the connection part, and the second support along axial direction of the elastic member, and wherein a space is defined by the through hole configured to accommodate the pump assembly.

13. The pump assembly of claim 1 further comprising:

a cylinder vertically open and having a hollow therein;

a seal cap disposed on an inner wall of the cylinder; and

the piston rod having an piston-inlet opened and closed by the seal cap disposed in a lower end of the piston rod and a path connected to the piston-inlet disposed at the upper end of the piston rod,

wherein the sealing part is at least partially inserted into the cylinder and is configured to restrain an ascent of the seal cap, and

wherein the elastic member is disposed between the stem and the sealing part and is configured to provide the elastic force to the stem from the sealing part.

14. The pump assembly of claim 13 , wherein the blade part is defined by protruding outward along a circumference of an upper end of the stem configured to support the upper end of the elastic member,

wherein a downwardly bent portion is defined along a circumference of the blade part and supports the elastic member configured to prevent separation of the elastic member.

15. The pump assembly of claim 14 , wherein the at least one air path of the blade part is defined on at least one region of the blade part being open.

16. The pump assembly of claim 13 , wherein the sealing part comprises:

a sidewall disposed to the cylinder and is configured to prevent an outward separation of the elastic member; and

a base part defined on a lower end of side wall,

wherein an upper surface of the base part supports a lower end of the elastic member.

17. The pump assembly of claim 13 , wherein the cylinder has an inlet communicating with a container and a valve preventing backflow, and

wherein the valve opens the inlet when an inner pressure of cylinder changes to a negative pressure.

18. The pump assembly of claim 13 , wherein a lower portion of the piston rod is surrounded by an inner surface of the seal cap sealing the piston-inlet of the piston rod and an upper portion of the piston rod is connected to the stem.