AIR PUMP

Abstract

An air pump has a body, a piston rod and a handle. The piston rod is movably inserted into the body and has a rod body, a convex ring and a first engaging part. The convex ring is laterally protruded from the rod body and has a retaining surface. The first engaging part is longitudinally mounted on the convex ring. The handle is mounted on the rod body and has a fixation trough, a retaining ring and a second engaging part. The retaining ring abuts against the retaining surface of the convex ring for preventing a relative rotation between the handle and the piston rod. The second engaging part is longitudinally mounted on the inner surface of the fixation trough and is engaged with the first engaging part of the piston rod. Therefore, the air pump increases the stability between the piston rod and the handle.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the Taiwan patent application No. 101201620, filed on Jan. 20, 2012, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an air pump, and more particularly to the air pump having a handle steadily mounted on a piston rod to prevent a relative rotation between the handle and the piston rod.

2. Description of Related Art

With reference to FIG. 6, an air pump comprises a body 50, a piston rod 60 and a handle 70. The body 50 has an end surface and a nozzle 51. The nozzle 51 is mounted on the end surface of the body 50. The piston rod 60 has a top end, a bottom end, an outer thread and a piston. The top end of the piston rod 60 is opposite to the bottom end of the piston rod 60. The bottom end of the piston rod 60 is movably inserted into the body 50. The outer thread is formed near the top end of the piston rod 60. The piston is mounted on the bottom end of the piston rod 60. The handle 70 has a fixation trough 71 and an inner thread. The fixation trough 71 is formed in the handle 70. The inner thread is formed in the fixation trough 71 and is screwed with the outer thread of the piston rod 60, such that the handle 70 is mounted on the top end of the piston rod 60.

The purpose of the handle 70 is to be held easily by a user and to afford inflation of a chamber such as a tire tube by pushing and pulling the piston rod 60. When the piston rod 60 is pushed and pulled, the force being pressed on the handle 70 may cause the relative rotation between the handle 70 and the piston rod 60, and then the handle 70 is easily loosened from the piston rod 60. Therefore, users can not hold the handle 70 steadily and need to reattach the handle 70 with the piston rod 60. Moreover, the screw force between the handle 70 and the piston rod 60 is decreased when the air pump is used for a period and also because the handle 70 frequently loosens and escapes and is then tightly screwed with the piston rod 60, causing the threaded engagement to be worn.

To overcome the shortcomings, the present invention provides an air pump to obviate the aforementioned problems.

SUMMARY OF THE INVENTION

An objective of the invention is to provide an air pump to prevent a relative rotation between a handle and a piston rod.

The air pump comprises a body, a piston rod and a handle. The body is hollow and has a nozzle. The piston rod is inserted into the body and has a rod body, a piston, a convex ring and a first engaging part. The rod body has a top end and a bottom end. The bottom end is opposite to the top end of the rod body and is inserted into the body. The piston is mounted on the bottom end of the rod body. The convex ring is radially formed on and protruded from the rod body near the top end of the rod body and has an outer surface, a bottom surface and a retaining surface. The retaining surface is mounted on the bottom surface of the convex ring of the piston rod. The first engaging part is longitudinally mounted on the outer surface of the convex ring of the piston rod. The handle is mounted on the top end of the rod body and has a connecting end, a face, a fixation trough, a retaining ring and a second engaging part. The connecting end is connected to the top end of the rod body. The face is formed on the connecting end of the handle rod. The fixation trough is formed in the face of the handle and has an inner surface. The retaining ring is radially protruded from the inner surface of the fixation trough and abuts against the retaining surface of the convex ring. The second engaging part is longitudinally mounted on the inner surface of the fixation trough and is engaged with the first engaging part of the piston rod.

With the engagement between the second engaging part of the handle and the first engaging part of the piston rod, the relative rotation between the handle and the piston rod is prevented. Therefore, the top end of the piston rod is steadily fixed into the fixation trough of the handle. Thus, the handle of the air pump is easily held and pressed in the pumping process of the air pump.

Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a first embodiment of an air pump in accordance with the present invention;

FIG. 2 is an enlarged exploded perspective view of the air pump in FIG. 1;

FIG. 3 is an enlarged cross sectional side view of the air pump in FIG. 1;

FIG. 4 is a cross sectional bottom view of the air pump along line 4-4 in FIG. 1;

FIG. 5 is an exploded perspective view of a second embodiment of an air pump in accordance with the present invention; and

FIG. 6 is a side view in partial section of an air pump in accordance with the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIGS. 1 and 2, an air pump in accordance with the present invention comprises a body 10, a piston rod 20 and a handle 30.

The body 10 is hollow and has an end surface and a nozzle 11. The nozzle 11 is mounted on the end surface of the body 10.

The piston rod 20 is movably inserted into the body 10. The piston rod 20 comprises a rod body, a piston 21, a convex ring 22 and a first engaging part 23. The rod body has a top end and a bottom end. The bottom end is opposite to the top end of the rod body and is inserted into the body 10. The piston 21 is mounted on the bottom end of the rod body. The convex ring 22 is radially formed on and protruded from the rod body near the top end of the rod body. The convex ring 22 has a retaining surface and an outer surface. The retaining surface is formed on a bottom surface of the convex ring 22 of the piston rod 20. The first engaging part 23 is longitudinally mounted on the outer surface of the convex ring 22 of the piston rod 20.

The handle 30 is steadily mounted on the top end of the rod body. The handle 30 has a connecting end, a face, a fixation trough 31, a retaining ring 32 and a second engaging part 33. The connecting end is connected to the top end of the rod body. The face is formed on the connecting end of the handle 30. The fixation trough 31 is formed in the face of the handle 30 and has an inner surface. The retaining ring 32 is radially protruded from the inner surface of the fixation trough 31 and abuts against the retaining surface of the convex ring 22. The second engaging part 33 is longitudinally mounted on the inner surface of the fixation trough 31 and is engaged with the first engaging part 23 of the piston rod 20.

With reference to FIG. 3, the retaining ring 32 abuts against the retaining surface of the convex ring 22. With reference to FIG. 4, the second engaging part 33 is engaged with the first engaging part 23 of the piston rod 20. Further, the handle 30 is a T-shaped handle and has a transverse part 301 and a longitudinal part 302, and the face and the fixation trough 31 of the handle 30 are formed on an end surface of the longitudinal part 302 of the handle 30. With reference to FIG. 5, the handle 30A is cylindrical. The face and the fixation trough 31 of the handle 30A are formed on an end surface of the cylindrical handle 30A. Preferably, the air pump has multiple slip-resistant ribs formed around and protruding from the handle 30A.

Furthermore, the first engaging part 23 of the piston rod 20 is a protruding rib, and the second engaging part 33 of the handle 30 is a groove, and the protruding rib is fixedly inserted into the groove. Alternatively, the first engaging part 23 of the piston rod 20 is a groove and the second engaging part 33 of the handle 30 is a protruding rib.

To combine the handle 30 with the piston rod 20, the second engaging part 33 of the handle 30 is aligned with the first engaging part 23 of the piston rod 20. The top end of the rod body of the piston rod 20 is then pressed into the fixation trough 31 of the handle 30, and the convex ring 22 and the first engaging part 23 are both located in the fixation trough 31 of the handle 30. The retaining ring 32 abuts against the retaining surface of the convex ring 22 to prevent the handle 30 being detached from the piston rod 20. With the engagement between the second engaging part 33 of the handle 30 and the first engaging part 23 of the piston rod 20, the relative rotation between the handle 30 and the piston rod 20 is prevented. Therefore, the air pump in accordance with the present invention does not have the problem of the decrement of the screw force between the handle and the piston rod of the prior art even when the air pump in accordance with the present invention is used for a long period.

Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

1. An air pump comprising:

a body being hollow and having: an end surface; and a nozzle mounted on the end surface;

a piston rod movably inserted into the body and having a rod body having: a top end; and a bottom end opposite to the top end of the rod body and inserted into the body; a piston mounted on the bottom end of the rod body; a convex ring radially formed on and protruded from the rod body near the top end of the rod body, and having: an outer surface; a bottom surface; a retaining surface formed on the bottom surface of the convex ring of the piston rod; and a first engaging part longitudinally mounted on the outer surface of the convex ring of the piston rod; and

a handle mounted on the top end of the rod body and having a connecting end connected to the top end of the rod body; a face formed on the connecting end of the handle; a fixation trough formed in the face of the handle and having an inner surface; a retaining ring radially protruded from the inner surface of the fixation trough and abutted against the retaining surface of the convex ring; and a second engaging part longitudinally mounted on the inner surface of the fixation trough and engaged with the first engaging part of the piston rod.

2. The air pump as claimed in claim 1, wherein the first engaging part of the piston rod is a protruding rib, and the second engaging part of the handle is a groove whereby the protruding rib is fixedly insertable in the groove.

3. The air pump as claimed in claim 1, wherein the first engaging part of the piston rod is a groove and the second engaging part of the handle is a protruding rib whereby the protruding rib is fixedly insertable in the groove.

4. The air pump as claimed in claim 1, wherein the handle is a T-shaped handle and has a transverse part and a longitudinal part, and the face of the handle is formed on an end surface of the longitudinal part of the handle.

5. The air pump as claimed in claim 2, wherein the handle is a T-shaped handle and has a transverse part and a longitudinal part, and the face of the handle is formed on an end surface of the longitudinal part of the handle.

6. The air pump as claimed in claim 3, wherein the handle is a T-shaped handle and has a transverse part and a longitudinal part, and the face of the handle is formed on an end surface of the longitudinal part of the handle.

7. The air pump as claimed in claim 1, wherein the handle is cylindrical and the face of the handle is formed on an end surface of the cylindrical handle.

8. The air pump as claimed in claim 2, wherein the handle is cylindrical and the face of the handle is formed on an end surface of the cylindrical handle.

9. The air pump as claimed in claim 3, wherein the handle is cylindrical and the face of the handle is formed on an end surface of the cylindrical handle.

10. The air pump as claimed in claim 7, wherein the air pump has multiple slip-resistant ribs and the slip-resistant ribs are formed around and protruding from the handle.

11. The air pump as claimed in claim 8, wherein the air pump has multiple slip-resistant ribs and the slip-resistant ribs are formed around and protruding from the handle.

12. The air pump as claimed in claim 9, wherein the air pump has multiple slip-resistant ribs and the slip-resistant ribs are formed around and protruding from the handle.