Novel air compressor with telescopic handle

Abstract

The utility model discloses a novel air compressor with a telescopic handle. The air compressor comprises an air compressor main body; a retractable handle is arranged on one side of the air compressor main body, and the retractable handle has a stretching state and a retracting state; the retractable handle comprises an inner tube, an outer tube, a bolt locking mechanism and a limiting part; the outer pipe is a hollow cast iron pipe body and comprises a first outer pipe and a second outer pipe; the inner pipe is a U-shaped hollow cast iron pipe body, and at least parts of the two ends of the inner pipe are shrunk into the first outer pipe and the second outer pipe respectively and can slide front and back. Screw holes are formed in the first outer pipe and the second outer pipe respectively, so that the inner pipe is locked at any sliding position relative to the first outer pipe and the second outer pipe; the limiting parts are arranged on the outer rings at the two ends of the inner pipe and used for being matched with the bolt locking mechanism to enable the inner pipe not to be disengaged from the first outer pipe and the second outer pipe when the inner pipe is not locked. The length of the telescopic handle can be adjusted according to the requirements of a user, the operation height conforming to human engineering can be provided when the telescopic handle is stretched, and the air compressor is convenient to push.

Description

Technical Field

[0001] This application relates to the field of air compressor devices, and more particularly to a novel air compressor with a retractable handle. Background Technology

[0002] An air compressor is a device that compresses air, primarily used to provide compressed air as a power source so that pneumatic tools (such as nailing tools, sanding tools, painting tools, etc.) can function properly. During use, air compressors need to be moved frequently, so they are usually equipped with casters and a handle, which is used to move the air compressor.

[0003] However, traditional air compressor handles are often one-piece designs, which cannot accommodate users of different heights, resulting in handles that are either too high or too low. Fixed handles cannot fit all users, increasing arm fatigue during air compressor operation. Some existing telescopic handles can only be locked in a limited number of fixed positions, failing to achieve continuous length adjustment, meaning users still cannot find the ideal handle length that perfectly suits their operating habits.

[0004] Therefore, the market urgently needs a new type of air compressor with a retractable handle to overcome the shortcomings of existing technology. Utility Model Content

[0005] In view of the above technical problems, the purpose of this application is to provide a novel air compressor with a retractable handle.

[0006] To achieve the above objectives, this application employs the following technical solution:

[0007] This application provides a novel air compressor with a retractable handle. The air compressor includes an air compressor body; a retractable handle is provided on one side of the air compressor body, and the retractable handle includes an extended state and a retracted state; the retractable handle includes an inner tube, an outer tube, a bolt locking mechanism, and a limiting part.

[0008] The outer tube is a hollow cast iron tube, including a first outer tube and a second outer tube; the inner tube is a U-shaped hollow cast iron tube, with at least a portion of both ends of the inner tube recessed into the first and second outer tubes respectively, and can slide along the hollow cavity direction of the first and second outer tubes; the first and second outer tubes are respectively provided with a first screw hole and a second screw hole, which are used to cooperate with the front end of the bolt locking mechanism to press against the inner tube, so that the inner tube is locked in any sliding position relative to the first and second outer tubes; the limiting part is provided on the outer ring of both ends of the inner tube, and is used to cooperate with the bolt locking mechanism to prevent the inner tube from coming out of the first and second outer tubes when the inner tube is not locked.

[0009] A further technical solution is that the limiting part is an internally threaded ring, and both ends of the inner tube are provided with external threads, and the external threads match the internal threads of the internally threaded ring; or,

[0010] The limiting part is a retaining spring, and the outer rings at both ends of the inner tube are provided with retaining grooves, which match the retaining spring.

[0011] A further technical solution is that both the inner tube and the outer tube are hollow cast iron cylindrical tubes, and the hollow cavity of the tube is a through cylindrical hole of equal diameter that extends along the axial direction of the tube.

[0012] A further technical solution is that, when the internal thread ring is used, the outer surface of the internal thread ring is in close contact with the inner surface of the outer tube.

[0013] A further technical solution is that the outer diameter of the outer tube ranges from 21 mm to 23 mm, and the inner diameter of the hollow cavity of the outer tube ranges from 18.5 mm to 20 mm; the outer diameter of the inner tube, which can be retracted into the first outer tube and the second outer tube, ranges from 16 mm to 17.5 mm.

[0014] A further technical solution is that the outer diameter of the outer tube is 22 mm, and the inner diameter of the hollow cavity of the outer tube is 19 mm; the outer diameter of the inner tube, which can be retracted into the first and second outer tubes, is 17 mm, and the inner diameter of the hollow cavity of the inner tube is 14 mm.

[0015] A further technical solution is that when the limiting part is an internal threaded ring, the outer surface of the internal threaded ring is in close contact with the inner surface of the outer tube.

[0016] A further technical solution is that both ends of the inner tube can be retracted to the portions of the first and second outer tubes, and an elongated limiting groove is provided on the outer surface facing the screw hole. The limiting groove is used to lock the inner tube in any sliding position relative to the first and second outer tubes when the front end of the bolt locking mechanism abuts against the inner tube.

[0017] A further technical solution is that the limiting part is a plurality of limiting blocks, which are distributed and fixed on the same outer ring at the end of the inner tube, and at least one limiting block is fixed on the surface of the inner tube facing the screw hole; or, the limiting part is a limiting ring fixed at the end of the inner tube.

[0018] A further technical solution is that the first screw hole and the second screw hole are symmetrically arranged along the central axis of the retractable handle, and are arranged opposite to each other on the sidewalls of the first outer tube and the second outer tube.

[0019] A further technical solution is that the ends of the first outer tube and the second outer tube away from the inner tube are each provided with an L-shaped adapter, and the ends of the adapters away from the first outer tube and the second outer tube are used to connect to the air compressor body.

[0020] Compared with related technologies, this utility model provides a novel air compressor with a retractable handle, which has the following advantages:

[0021] The air compressor's telescopic handle employs a telescopic sleeve design with inner and outer tubes (first and second outer tubes). The inner tube is a U-shaped hollow cast iron tube, with both ends recessed within the outer tube and capable of sliding back and forth. The outer tube is also a hollow cast iron tube. A threaded hole is provided inside the outer tube for engagement with a bolt locking mechanism. The front end of the bolt locking mechanism abuts against the inner tube, thereby locking the inner tube in any sliding position, enabling length adjustment and fixation of the telescopic handle.

[0022] The limiting parts are located on the outer rings at both ends of the inner tube. Even if the inner tube is not locked, the limiting parts can prevent the inner tube from coming out of the outer tube with the help of the bolt locking mechanism. When the inner tube slides to the desired position, it can be further locked by the bolt locking mechanism to ensure stability during use.

[0023] Therefore, the telescopic handle can be adjusted in length according to the user's needs. When extended, it provides an ergonomic operating height for easy pushing of the air compressor; when retracted, it reduces the size of the air compressor, facilitating packaging and transportation. The telescopic sleeve design of the inner and outer tubes, combined with a bolt locking mechanism, allows the user to quickly adjust the handle length as needed and securely lock it in place. A limiting part prevents the inner tube from detaching from the outer tube, ensuring that the handle will not be damaged or cause operational accidents due to accidental slippage of the inner tube during use or movement. The bolt locking mechanism further enhances the stability of the handle, ensuring it will not loosen or slip when pushing the air compressor, improving safety during use.

[0024] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description

[0025] Figure 1 This illustration shows a structural schematic diagram of a retractable handle for an air compressor according to an embodiment of this application;

[0026] Figure 2 This illustration shows a structural diagram of a retractable handle provided in an embodiment of this application from another angle;

[0027] Figure 3A partial structural schematic diagram of a retractable handle provided in an embodiment of this application is shown.

[0028] The diagram shows: 10, first outer tube; 20, bolt locking mechanism; 30, inner tube; 40, second outer tube; 50, limiting block; 60, adapter. Detailed Implementation

[0029] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many other different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0030] The technical solutions of the embodiments of this application and how the technical solutions of the embodiments of this application solve the above-mentioned technical problems will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. The order of description of the embodiments below is not intended to limit the preferred order of embodiments. The same or similar concepts or processes may not be described again in some embodiments. Obviously, the described embodiments are some embodiments of the embodiments of this application, but not all embodiments.

[0031] See Figure 1 , Figure 2 and Figure 3 This embodiment provides a novel air compressor with a retractable handle. The air compressor includes an air compressor body; a retractable handle is provided on one side of the air compressor body, and the retractable handle includes an extended state and a retracted state; the retractable handle includes an inner tube 30, an outer tube, a bolt locking mechanism 20, and a limiting part.

[0032] The outer tube is a hollow cast iron tube, including a first outer tube 10 and a second outer tube 40; the inner tube 30 is a U-shaped hollow cast iron tube, with at least a portion of both ends of the inner tube 30 recessed into the first outer tube 10 and the second outer tube 40 respectively, and can slide along the hollow cavity direction of the first outer tube 10 and the second outer tube 40; the first outer tube 10 and the second outer tube 40 are respectively provided with a first screw hole and a second screw hole, which are used to cooperate with the front end of the bolt locking mechanism 20 to press against the inner tube 30, so that the inner tube 30 is locked in any sliding position relative to the first outer tube 10 and the second outer tube 40; the limiting part is provided on the outer ring of both ends of the inner tube 30, which is used to cooperate with the bolt locking mechanism 20 to prevent the inner tube 30 from coming out of the first outer tube 10 and the second outer tube 40 when the inner tube 30 is not locked.

[0033] The telescopic handle of the air compressor adopts a telescopic sleeve design of inner tube 30 and outer tubes (first outer tube 10 and second outer tube 40). The inner tube 30 is a U-shaped hollow cast iron tube, with both ends recessed inside the outer tube and able to slide back and forth. The outer tube is also a hollow cast iron tube. A threaded hole is provided inside the outer tube, which engages with the bolt locking mechanism 20. The front end of the bolt locking mechanism 20 can abut against the outer wall of the inner tube 30, thereby locking the inner tube 30 in any sliding position, realizing the length adjustment and fixation of the telescopic handle.

[0034] The limiting parts are located on the outer rings at both ends of the inner tube 30. Even if the inner tube 30 is not locked, the limiting parts can prevent the inner tube 30 from coming out of the outer tube with the cooperation of the bolt locking mechanism 20. When the inner tube 30 slides to the desired position, it can be further locked by the bolt locking mechanism 20 to ensure stability during use.

[0035] The advantages of the above technical solution are that the telescopic handle can be adjusted in length according to the user's needs. When extended, it provides an ergonomic operating height for easy pushing of the air compressor; when retracted, it reduces the size of the air compressor, facilitating packaging and transportation. The telescopic sleeve design of the inner tube 30 and the outer tube, combined with the bolt locking mechanism 20, allows the user to quickly adjust the handle length as needed and securely lock it. The limiting part is used to prevent the inner tube 30 from coming out of the outer tube, ensuring that the handle will not be damaged or cause operational accidents due to accidental slippage of the inner tube 30 during use or movement. The bolt locking mechanism 20 further enhances the stability of the handle, ensuring that it will not loosen or slip when pushing the air compressor, improving the safety of use.

[0036] In some embodiments, the limiting part is an internally threaded ring, and both ends of the inner tube 30 are provided with external threads, which match the internal threads of the internally threaded ring; or,

[0037] The limiting part is a retaining ring, and the outer rings at both ends of the inner tube 30 are provided with retaining grooves, which match the retaining ring.

[0038] The internal threaded ring is installed on the outer ring of the inner tube 30. The inner tube 30 has external threads at both ends, which cooperate with the internal threads of the internal threaded ring.

[0039] When the internally threaded ring is installed on the inner tube 30, the external thread at the end of the inner tube 30 engages with the internal thread of the internally threaded ring, allowing the internally threaded ring to move axially for adjustment. Simultaneously, when the inner tube 30 slides away from the first outer tube 10 and the second outer tube 40, the front end of the bolt locking mechanism 20 abuts against the internally threaded ring, preventing the inner tube 30 from disengaging from the first outer tube 10 and the second outer tube 40. When the retaining ring is installed on the inner tube 30, it engages in a groove on the outer ring of the inner tube 30, thereby limiting further sliding of the inner tube 30 and preventing it from dislodging from the outer tube. Its specific effect is similar to that of the internally threaded ring and will not be elaborated further.

[0040] The above technical solution has the following effect: when using an internal threaded ring, the degree of limitation of the inner tube 30 relative to the first outer tube 10 and the second outer tube 40 can be adjusted by the movable internal threaded ring. When using a snap ring, it can reduce costs.

[0041] In some embodiments, both the inner tube 30 and the outer tube are hollow cast iron cylindrical tubes, and the hollow cavity of the tube is a through cylindrical hole of equal diameter that extends along the axial direction of the tube.

[0042] The inner tube 30, the first outer tube 10, and the second outer tube 40 are all hollow cast iron cylindrical tubes. The first outer tube 10 and the second outer tube 40 have through cylindrical holes of equal diameter extending axially, forming a continuous, stepless straight channel. The inner tube 30 also has through cylindrical holes of equal diameter extending axially, forming a continuous U-shaped channel. Both ends of the inner tube 30 are inserted into the through holes of the first outer tube 10 and the second outer tube 40, respectively, forming a coaxial connection. The equal diameter design of the through holes maintains a uniform gap between the outer wall of the inner tube 30 and the inner wall of the outer tube, achieving low-friction linear sliding. A limiting part (such as a snap ring or threaded ring) is installed on the outer periphery of the end of the inner tube 30. When the inner tube 30 slides to its limit position, the limiting part abuts against the bolt locking mechanism 20, preventing the inner tube 30 from dislodging from the outer tube.

[0043] Hollow cast iron cylindrical tubes retain the high strength and impact resistance of cast iron. The through-hole cylindrical design allows for uniform material removal, significantly reducing overall weight and facilitating manual pushing, pulling, and transportation. The uniform diameter through-hole can be formed in a single drilling or broaching operation, reducing multi-stage stepped hole machining, machining steps, and tool types, thus lowering manufacturing costs. The uniform diameter and continuous inner wall of the through-hole eliminate steps or abrupt cross-sections, resulting in low sliding resistance and maintaining stable expansion and contraction even after long-term use, reducing jamming caused by uneven wear.

[0044] In some embodiments, the outer diameter of the outer tube ranges from 21 mm to 23 mm, and the inner diameter of the hollow cavity of the outer tube ranges from 18.5 mm to 20 mm; the outer diameter of the inner tube 30, which can be retracted into the first and second outer tubes, ranges from 16 mm to 17.5 mm. Preferably, the outer diameter of the outer tube is 22 mm, and the inner diameter of the hollow cavity of the outer tube is 19 mm; the outer diameter of the inner tube 30, which can be retracted into the first and second outer tubes, is 17 mm, and the inner diameter of the hollow cavity of the inner tube 30 is 14 mm.

[0045] The preferred pipe clearance dimensions described above better prevent jamming due to excessive tightness or wobbling due to excessive looseness. A wall thickness of not less than 3 mm prevents localized crushing caused by the pre-tightening force of the locking bolts; a 2 mm pipe clearance ensures that manual unlocking is still possible even under extreme working conditions (mud and sand intrusion), preventing jamming and handling accidents.

[0046] In some embodiments, when the limiting part is an internally threaded ring, the outer surface of the internally threaded ring is in close contact with the inner surface of the outer tube.

[0047] The effect of the above technical solution is that the internal threaded ring is installed at the end of the inner tube 30, and its outer surface is in close contact with the inner surface of the outer tube. The close contact between the internal threaded ring and the inner surface of the outer tube provides radial support for the inner tube 30, preventing it from shaking in the outer tube. At the same time, the bolt locking mechanism 20 further ensures the fixing effect of the inner tube 30.

[0048] In some embodiments, both ends of the inner tube 30 can be retracted to portions of the first outer tube 10 and the second outer tube 40, and an elongated limiting groove is provided on the outer surface facing the screw hole. The limiting groove is used to lock the inner tube 30 in any sliding position relative to the first outer tube 10 and the second outer tube 40 when the front end of the bolt locking mechanism 20 abuts against the inner tube 30.

[0049] The effect of the above technical solution is that both ends of the inner tube 30 can be retracted into the first outer tube 10 and the second outer tube 40, and can slide back and forth within them. An elongated limiting groove is provided on the outer surface of the inner tube 30 facing the screw hole. When it is necessary to lock the inner tube 30, the front end of the bolt locking mechanism 20 passes through the screw hole of the outer tube and abuts against the bottom surface of the elongated limiting groove on the inner tube 30. By tightening the bolt locking mechanism 20, the inner tube 30 is firmly fixed inside the outer tube, preventing it from sliding.

[0050] It can be assumed that when the inner tube 30 has a long strip-shaped limiting groove on its outer surface facing the screw hole, the bottom surface of the limiting groove is flat, which can ensure that the front end of the bolt locking mechanism 20 and the inner tube 30 form a stable contact and effective force transmission.

[0051] In some embodiments, the limiting part is a plurality of limiting blocks 50, which are distributed and fixed on the same outer ring at the end of the inner tube 30, and at least one limiting block 50 is fixed on the surface of the inner tube 30 facing the screw hole; or, the limiting part is a limiting ring fixed to the end of the inner tube 30.

[0052] The above technical solution achieves the following effect: multiple limiting blocks 50 are distributed and fixed on the same outer ring at the end of the inner tube 30, with at least one limiting block 50 fixed on the surface of the inner tube 30 facing the screw hole. When the inner tube 30 is inserted into the outer tube and slides to the appropriate position, the limiting block 50 cooperates with the bolt locking mechanism 20 of the outer tube to prevent the inner tube 30 from sliding excessively or coming out. Simultaneously, the multiple limiting blocks 50 limit the inner tube 30 from different directions, providing more stable support compared to a single limiting part. The multiple limiting blocks 50 distribute the force, better bearing the various forces experienced by the inner tube 30 during use, thus improving the strength and durability of the entire handle structure.

[0053] In some embodiments, the first screw hole and the second screw hole are symmetrically arranged along the central axis of the retractable handle and are arranged opposite to each other on the sidewalls of the first outer tube and the second outer tube.

[0054] The inner tube 30 is a U-shaped hollow cast iron tube, with both ends recessed into the first outer tube 10 and the second outer tube 40, respectively, and can slide back and forth along the central axis of the outer tube. When the handle length needs to be adjusted, the user slides the inner tube 30, moving it within the first outer tube 10 and the second outer tube 40, thus achieving the extension and retraction function of the handle. The first outer tube 10 and the second outer tube 40 are respectively provided with screw holes (first screw hole and second screw hole), which are symmetrically arranged along the central axis of the handle and back-to-back. The front end of the bolt locking mechanism 20 can pass through the first screw hole and the second screw hole to abut against the inner tube 30. When the inner tube 30 slides to the desired position, tightening the bolt locking mechanism 20 causes its front end to pass through the screw hole of the outer tube and abut against the inner tube 30, thereby locking the inner tube 30 in that position and preventing it from sliding.

[0055] Because the screw holes are symmetrically arranged along the central axis and back to back, the bolt locking mechanism 20 is subjected to more uniform force when it is pressed against the inner tube 30, which can better fix the inner tube 30 and avoid loosening or slippage caused by uneven force.

[0056] In some embodiments, both the first outer tube 10 and the second outer tube 40 have an L-shaped adapter 60 at the end away from the inner tube 30. The end of the adapter 60 away from the first outer tube 10 and the second outer tube 40 is used to connect to the air compressor body.

[0057] The L-shaped adapter 60 is integrally formed or detachably configured at the far end of the two outer tubes (i.e., the end furthest from the inner tube 30). The far end of the adapter 60 is fixedly connected to the side wall or frame of the air compressor body by bolts, welding, or riveting. When the user pushes or pulls the telescopic handle, the force is transmitted along the inner tube 30 → outer tube → L-shaped adapter 60 → air compressor body. The L-shaped bend changes the direction of the moment, converting the horizontal push-pull load into a horizontal traction force on the air compressor, avoiding direct vertical bending moment and reducing stress concentration at the connection. In practical applications, the vertical (or horizontal) section of the L-shaped adapter 60 fits against the mounting surface of the air compressor body, providing at least two mounting holes for multiple bolt fixation to prevent rotation.

[0058] To address the issues of a straight connection between the handle and the main body resulting in a large overall length, making packaging difficult, and a large turning radius that increases the risk of collisions in narrow spaces, the L-shaped adapter 60 allows the handle to be installed on the side wall of the main body. This results in a more compact overall profile, a smaller turning radius, and easier maneuverability in confined spaces. Furthermore, the L-shaped adapter 60 uses a bending structure to convert horizontal tensile force into shear force, leading to a more even load distribution and a significantly longer service life.

[0059] As an example, a novel air compressor with a retractable handle is provided, wherein a retractable handle is provided on one side of the air compressor body. The handle has two states: extended and retracted, and consists of a U-shaped hollow cast iron inner tube 30, a pair of hollow cast iron outer tubes (first outer tube 10 and second outer tube 40), a bolt locking mechanism 20 (e.g., an internal hexagonal bolt or an external hexagonal bolt), an L-shaped adapter 60, and a limiting part. The tube bodies of the two outer tubes are both through cylindrical holes of equal diameter extending axially. The two ends of the inner tube 30 are slidably retracted into the corresponding outer tubes. Each outer tube has an L-shaped adapter 60 at its distal end, which connects to the air compressor body, so that the push-pull load is transmitted to the air compressor body after bending. The machine has a compact profile and a small turning radius. The two outer tubes are respectively provided with a first screw hole and a second screw hole arranged symmetrically and oppositely along the central axis of the handle near the end of the inner tube 30. The front end of the bolt locking mechanism 20 (bolt) passes through the screw hole and abuts against the inner tube 30, locking the inner tube 30 in any sliding position. The outer surface of the inner tube 30 facing the screw hole is also provided with a long strip-shaped limiting groove, which cooperates with the front end of the bolt to achieve positioning. The limiting part is provided on the outer ring of both ends of the inner tube 30. It can be an internal thread ring or a snap ring structure, or it can be multiple limiting blocks 50 or an integral limiting ring. When not locked, the bolt locking mechanism 20 is not abutting against the inner tube 30 and still passes through the screw hole. In this case, it can cooperate with the limiting part to prevent the inner tube 30 from coming out when not locked.

[0060] The air compressor provided in this application is, for example, a portable piston air compressor or a mobile screw air compressor. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0061] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are configured to distinguish similar objects and are not necessarily configured to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0062] This application describes the invention from the perspectives of purpose, performance, progress, and novelty, and it meets the functional enhancement and use requirements emphasized by the Patent Law. The above description and drawings are merely preferred embodiments of this application and are not intended to limit this application. Therefore, all structures, devices, features, etc., that are similar to or identical to those of this application, i.e., all equivalent substitutions or modifications made in accordance with the scope of this patent application, shall fall within the scope of protection of this patent application.

Claims

1. A novel air compressor with a retractable handle, the air compressor comprising an air compressor body; characterized in that, A retractable handle is provided on one side of the air compressor body. The retractable handle has an extended state and a retracted state. The retractable handle includes an inner tube, an outer tube, a bolt locking mechanism, and a limiting part. The outer tube is a hollow cast iron tube, including a first outer tube and a second outer tube; the inner tube is a U-shaped hollow cast iron tube, with at least a portion of both ends of the inner tube recessed into the first and second outer tubes respectively, and can slide along the hollow cavity direction of the first and second outer tubes; the first and second outer tubes are respectively provided with a first screw hole and a second screw hole, which are used to cooperate with the front end of the bolt locking mechanism to press against the inner tube, so that the inner tube is locked in any sliding position relative to the first and second outer tubes; the limiting part is provided on the outer ring of both ends of the inner tube, and is used to cooperate with the bolt locking mechanism to prevent the inner tube from coming out of the first and second outer tubes when the inner tube is not locked.

2. The air compressor according to claim 1, characterized in that, The limiting part is an internally threaded ring, and the two ends of the inner tube are provided with external threads, which match the internal threads of the internally threaded ring; or, the limiting part is a retaining ring, and the outer rings at both ends of the inner tube are provided with retaining grooves, which match the retaining rings.

3. The air compressor according to claim 2, characterized in that, Both the inner tube and the outer tube are hollow cast iron cylindrical tubes, and the hollow cavity of the tube is a through cylindrical hole of equal diameter that extends along the axial direction of the tube.

4. The air compressor according to claim 3, characterized in that, When the limiting part is an internally threaded ring, the outer surface of the internally threaded ring is in close contact with the inner surface of the outer tube.

5. The air compressor according to claim 3, characterized in that, The outer diameter of the outer tube ranges from 21 mm to 23 mm, and the inner diameter of the hollow cavity of the outer tube ranges from 18.5 mm to 20 mm; the outer diameter of the inner tube, which can be retracted into the first and second outer tubes, ranges from 16 mm to 17.5 mm.

6. The air compressor according to claim 5, characterized in that, The outer diameter of the outer tube is 22 mm, and the inner diameter of the hollow cavity of the outer tube is 19 mm; the outer diameter of the inner tube, which can be retracted into the first and second outer tubes, is 17 mm, and the inner diameter of the hollow cavity of the inner tube is 14 mm.

7. The air compressor according to claim 1, characterized in that, Both ends of the inner tube can be retracted into the first outer tube and the second outer tube. An elongated limiting groove is provided on the outer surface facing the screw hole. The limiting groove is used to lock the inner tube in any sliding position relative to the first outer tube and the second outer tube when the front end of the bolt locking mechanism abuts against the inner tube.

8. The air compressor according to claim 1, characterized in that, The limiting part consists of multiple limiting blocks, which are distributed and fixed on the same outer ring at the end of the inner tube, and at least one limiting block is fixed on the surface of the inner tube facing the screw hole; or, the limiting part is a limiting ring fixed at the end of the inner tube.

9. The air compressor according to claim 1, characterized in that, The first screw hole and the second screw hole are symmetrically arranged along the central axis of the retractable handle and are arranged opposite to each other on the side walls of the first outer tube and the second outer tube.

10. The air compressor according to claim 1, characterized in that, Both the first outer tube and the second outer tube have an L-shaped adapter at the end away from the inner tube. The end of the adapter away from the first outer tube and the second outer tube is used to connect to the air compressor body.

Images