Self-locking jack

Abstract

The invention discloses a self-locking jack, and relates to the technical field of jacks. The jack comprises a base, a mounting frame and a pair of clamping arms, a cylinder body and a lifting rod are arranged in the middle of the base, and the top end of the lifting rod is connected with an outer cylinder with notch teeth on the periphery through an ejector head. The clamping arms are hinged to the two sides of the mounting frame through rotating rods, and locking chucks are arranged on the inner sides of the clamping arms. A turntable in the middle of the mounting frame is connected with fixing rods of the clamping arms through connecting rods. And a pre-tightening spring for driving the clamping arms to have a closing trend is arranged between the rotating rod and the mounting frame. A locking air cylinder hinged to the rotary disc is arranged on the base. Through cooperative work of the pre-tightening spring and the locking air cylinder, the locking chuck of the clamping arm can be meshed with or separated from the notch teeth of the outer cylinder, and therefore active locking, unlocking and fault safety type passive locking are achieved. By means of the structure, the problems that a traditional jack is unreliable in locking and insufficient in stability are effectively solved, and safety and reliability in the jacking process are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of jacks, in particular to a self-locking jack. BACKGROUND

[0002] A jack is a common lifting device, widely used in vehicle maintenance, industrial lifting and other fields. The traditional jack usually relies on hydraulic or mechanical structure to maintain position during jacking, but has problems such as insufficient stability and unreliable locking. For example, when the hydraulic pressure is lost or the load suddenly changes, the jack may suddenly fall back, causing safety hazards. In the prior art, some jacks have adopted additional locking mechanisms, but the structure is complex and cannot automatically lock in case of failure. Therefore, there is an urgent need for a self-locking jack with a fail-safe passive locking function. SUMMARY

[0003] The present application provides a self-locking jack, aiming to solve the problem of insufficient locking function of the jack in the prior art, and to provide a reliable self-locking mechanism to improve the stability and safety of the jacking process.

[0004] The technical solution adopted by the present application is as follows: a self-locking jack, comprising a base, a mounting frame mounted on the base, and a pair of clamping arms. The middle part of the base is fixed with a cylinder body, and a liftable lifting rod is arranged in the cylinder body. The top end of the lifting rod is provided with a jack head, and the bottom of the jack head is fixed with an annular outer cylinder. The outer peripheral wall of the outer cylinder is uniformly distributed with a plurality of notched teeth along the axial direction, and each notched tooth forms a square edge facing the bottom of the cylinder body. A pair of clamping arms are symmetrically arranged on the radial sides of the outer cylinder, and a rotating shaft is fixed to the outer side of each clamping arm. The rotating shaft is rotatably connected to the two sides of the mounting frame through a pin shaft. A rotating disc is rotatably mounted in the middle part of the mounting frame through a center shaft, and two rotatingly connected connecting rods are arranged at the two ends of the rotating disc. Symmetrical fixed rods are arranged on the rotating shafts of the two clamping arms, and the other end of the connecting rod is rotatably connected to the same side fixed rod through a joint bearing. A pre-tightening spring is fixed between the middle part of the rotating shaft and the mounting frame, and the pre-tightening spring drives the pair of clamping arms to have a tendency to close in the direction of the axis of the outer cylinder.

[0005] Further, the pre-tightening force of the pre-tightening spring causes the rotating shaft to have a tendency to rotate in the direction of the axis of the outer cylinder, thereby driving the clamping arms to close.

[0006] Further, a locking cylinder is also arranged on the base, and the cylinder body of the locking cylinder is rotatably connected to the base, and the piston rod of the locking cylinder is hinged to the rotating disc. The axial direction of the locking cylinder and the axial direction of the connecting rod are staggered in space, thereby forming a lever linkage mechanism together with the locking cylinder, the rotating disc and the connecting rod.

[0007] Further, a locking chuck is formed at the inner side of the end of each clamping arm, the inner contour of the locking chuck is matched with the outer cylindrical surface of the outer cylinder, and the end face is a flat surface which can engage with the square edge of the notched tooth.

[0008] Further, when in the locked state, the locking jaws of the clamping arms are pressed and engaged under the square edges of the notched teeth to prevent the outer cylinder from falling back under the action of the pre-tightening spring.

[0009] Further, when the piston rod of the locking cylinder is fully extended, the driving disc is rotated to overcome the pre-tightening force of the pre-tightening spring through the connecting rod, causing the clamping arms to rotate to the unlocked position where the locking jaws are completely disengaged from the notched teeth of the outer cylinder.

[0010] Further, during normal jacking of the outer cylinder, if the locking cylinder loses pressure and is in a floating state, the pre-tightening spring will drive the clamping arms to always maintain a closing tendency, and ensure that the locking jaws can be immediately engaged under the square edges after passing a notched tooth, achieving a fail-safe passive locking.

[0011] Further, the pre-tightening spring works in coordination with the locking cylinder, specifically: in the active unlocking process, the locking cylinder provides the main force to overcome the pre-tightening force and load pressure of the pre-tightening spring; in the active locking or passive locking, the pre-tightening spring provides a continuous pressing force to eliminate the transmission gap and ensure the reliable engagement of the locking jaws with the notched teeth.

[0012] Further, the base is integrated with a hydraulic balance valve for controlling the jacking speed and stability, and is also provided with a lifting socket for lifting and handling.

[0013] Compared with the prior art, the beneficial effects of the present application are: The continuous pressing force of the pre-tightening spring drives the clamping arms to close inward, even if the locking cylinder is in a floating state due to pressure loss, power failure, or other faults, the locking jaws of the clamping arms can automatically engage under the square edges of the notched teeth of the outer cylinder under the action of external load, achieving passive locking. This design effectively prevents the sudden falling back of the jack when the hydraulic pressure fails or the load suddenly changes, significantly improving the safety and reliability of the equipment and avoiding potential safety hazards.

[0014] The locking cylinder provides active driving force through the lever linkage mechanism (including the driving disc and connecting rod), which can effectively overcome the pre-tightening force of the pre-tightening spring and the load pressure, causing the clamping arms to quickly rotate to the unlocked position. This design makes the unlocking process controllable and labor-saving, improving the operational convenience.

[0015] The locking cylinder and the pre-tightening spring work in coordination: in the active unlocking process, the locking cylinder provides the main force; in the locking process, the pre-tightening spring provides a continuous pressing force. This coordination mechanism simplifies the structure, reduces the use of additional locking components, and improves the overall response speed and energy efficiency.

[0016] The base is integrated with a hydraulic balance valve, which can accurately control the jacking speed and hydraulic fluctuation, reduce impact and vibration, and ensure smooth jacking process. In addition, the clamping arms always maintain a closed tendency during normal jacking, avoiding the shaking or deviation that may occur during jacking of traditional jacks. The base is provided with a lifting socket, which facilitates handling and positioning by lifting equipment, and is suitable for various working environments, improving the portability and applicability of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, together with the embodiments of the application, to explain the application, and do not constitute a limitation on the application. In the drawings: Figure 1 is a structural schematic diagram of the application; Figure 2 is a structural schematic diagram of the application in the locked state; Figure 3 is a structural schematic diagram of the application from the side; Figure 4 is Figure 3 is an enlarged schematic diagram of the structure of part A in the middle; Figure 5 is a structural schematic diagram of the application from the inside; Figure 6 is a structural schematic diagram of the application in the unlocked state.

[0018] In the drawings: 1 - base; 2 - mounting bracket; 3 - clamping arm; 4 - cylinder; 5 - lifting rod; 6 - top head; 7 - outer cylinder; 8 - rotating disc; 9 - connecting rod; 10 - fixed rod; 11 - pre-tightening spring; 12 - locking cylinder; 13 - hydraulic balance valve; 14 - lifting socket; 31 - rotating rod; 32 - locking chuck; 71 - notched tooth. DETAILED DESCRIPTION

[0019] The preferred embodiments of the application will be described below in conjunction with the accompanying drawings, it should be understood that the preferred embodiments described herein are only used to illustrate and explain the application, and do not limit the application.

[0020] The self-locking jack of the application comprises a base 1, a mounting bracket 2 mounted on the base 1, and a pair of clamping arms 3. The top center of the base 1 is fixedly connected with a cylinder 4. The cylinder 4 is internally provided with a liftable lifting rod 5, and the top end of the lifting rod 5 is connected with a top head 6. The bottom of the top head 6 is fixed with an annular outer cylinder 7. The outer peripheral wall of the outer cylinder 7 is uniformly distributed with a plurality of notched teeth 71 along the axial direction. The bottom of each notched tooth 71 is formed with a square edge facing the bottom of the cylinder 4, which is the locking point of the locking chuck 32.

[0021] The mounting frame 2 is fixed on the base 1 for supporting and mounting other components. A pair of clamping arms 3 are symmetrically arranged on both sides of the outer cylinder 7 in the radial direction. The outer side of each clamping arm 3 is fixed with a rotating rod 31 which is rotatably connected to the side wall of the mounting frame 2 through a pin shaft.

[0022] A rotating disc 8 is mounted on the central axis of the mounting frame 2 and can rotate around the central axis. The two ends of the rotating disc 8 are each connected with a connecting rod 9.

[0023] The rotating rods 31 of the two clamping arms 3 are symmetrically fixed with a fixed rod 10. The other end of the connecting rod 9 is rotatably connected with the same side fixed rod 10 through a joint bearing. A pre-tightening spring 11 is fixed between the middle part of the rotating rod 31 and the mounting frame 2. The pre-tightening spring 11 provides an inward pushing force, so that the pair of clamping arms 3 naturally rotate towards the axis direction of the outer cylinder 7 without external intervention.

[0024] The base 1 is also provided with a locking cylinder 12. The cylinder body of the locking cylinder 12 is rotatably connected with the base 1, which can be understood as rotatable around a certain axis or fixed on the base. The piston rod of the locking cylinder 12 is hinged with the rotating disc 8. The axis of the locking cylinder 12 and the axis of the connecting rod 9 are staggered in space. The locking cylinder 12, the rotating disc 8 and the connecting rod 9 together constitute a lever linkage mechanism. When the locking cylinder 12 works, the extension or retraction of the piston rod will drive the rotating disc 8 to rotate, and then control the opening and closing of the clamping arms 3 through the connecting rod 9.

[0025] The inner side of the end of each clamping arm 3 is formed with a locking chuck 32. The inner contour of the locking chuck 32 is designed to match the outer cylindrical surface of the outer cylinder 7 and can be tightly fitted. The end face of the locking chuck 32 is flat, and its shape can engage with the square edge of the notched tooth 71 of the outer cylinder 7.

[0026] Working principle: Normal jacking process: when starting the jack for jacking, the hydraulic system injects hydraulic oil into the cylinder body 4, and the lifting rod 5 and the outer cylinder 7 rise upward. In this process, the clamping arms 3 are pushed outward by the upward sliding without locking movement of the notched teeth 71 on the outer cylinder 7. As the stroke is extended, the clamping arms 3 are retracted one by one through the spring pressure of the connecting rod 9, and the pre-tightening spring 11 always provides an inward closing tendency force to drive the clamping arms 3 to keep the inward folding state.

[0027] Locking state: when the jack needs to be locked, the drive of the locking cylinder 12 can be stopped. At this time, the elastic force of the pre-tightening spring 11 drives the clamping arms 3 to close inward. At this time, if the outer cylinder 7 is rising, the locking chuck 32 will move with the outer cylinder 7 and immediately be clamped under the square edge after passing a notched tooth 71. At this time, the jack is in the locking state, and the outer cylinder 7 cannot fall back.

[0028] Passive locking / failsafe locking: During normal jacking of the jack, even if the locking cylinder 12 is in a floating state due to some reason such as pressure loss, power failure, etc., the pre-tightening spring 11 will still drive the clamping arm 3 to always maintain the tendency to close inward. This means that at any time, as long as the outer cylinder 7 is in the process of rising, the locking chuck 32 will actively seek and clamp into the square edge of the notched tooth 71, thereby achieving failsafe passive locking. For example, during the rising process, when the clamping arm 3 rotates to the adjacent position of the notched tooth 71, the force of the pre-tightening spring 11 will cause the clamping arm 3 to further close, so that the locking chuck 32 is instantaneously engaged below the square edge of the notched tooth 71, preventing the outer cylinder 7 from falling back. The pre-tightening spring 11 provides a continuous pressing force. This continuous pressing force not only eliminates the transmission gap of the linkage mechanism such as the clamping arm 3 and the connecting rod 9, ensuring the smoothness of the movement, but more importantly, it ensures the reliable engagement between the locking chuck 32 and the notched tooth 71, which can maintain the locking state even under slight vibration or position change.

[0029] Active unlocking during unlocking process: When unlocking is needed, the piston rod of the locking cylinder 12 extends, overcoming the pre-pressing force of the pre-tightening spring 11 and the possible load pressure, and drives the clamping arm 3 to rotate to its unlocking position where the locking chuck 32 is completely separated from the notched tooth 71 of the outer cylinder 7. At this time, the outer cylinder 7 can freely descend. The pre-tightening spring 11 and the locking cylinder 12 work together to ensure the reliability and stability of the jack. The locking cylinder 12 provides strong active force to overcome the pre-pressing force of the pre-tightening spring 11, ensuring the smooth progress of the unlocking process.

[0030] The base 1 is integrated with a hydraulic balance valve 13 for accurately controlling the jacking speed of the jack and maintaining its stability, preventing impact caused by hydraulic fluctuations. In addition, the base 1 is also provided with a lifting socket 14 for hoisting and carrying, facilitating the transportation and deployment of the jack.

[0031] In summary, the self-locking jack provided by the present application achieves safe and reliable locking under various working conditions through ingenious mechanical linkage and spring pre-tightening design, combined with active control of the locking cylinder, especially in emergency situations or hydraulic pressure loss, still providing effective safety protection.

Claims

1. A self-locking jack comprising a base (1), a mounting frame (2) mounted on the base (1), and a pair of clamping arms (3), characterized in that: The middle part of the base (1) is fixed with a cylinder body (4), the cylinder body (4) is provided with a liftable lifting rod (5), the top end of the lifting rod (5) is provided with a top head (6), the bottom of the top head (6) is fixed with an annular outer cylinder (7), the outer circumferential wall of the outer cylinder (7) is uniformly distributed with a plurality of notched teeth (71) along the axial direction, each notched tooth (71) is formed with a square edge towards the bottom of the cylinder body (4), the pair of clamping arms (3) are symmetrically arranged on the radial two sides of the outer cylinder (7), the outer side of each clamping arm (3) is fixed with a rotating rod (31), the rotating rod (31) is rotatably connected to the two sides of the mounting frame (2) through a pin shaft, the middle part of the mounting frame (2) is rotatably mounted with a rotating disc (8) through a central shaft, the two ends of the rotating disc (8) are provided with rotatably connected connecting rods (9), the rotating rods (31) of the two clamping arms (3) are symmetrically provided with fixed rods (10), the other end of the connecting rod (9) is rotatably connected with the same side fixed rod (10) through a joint bearing, the middle part of the rotating rod (31) and the mounting frame (2) are fixed with a pre-tightening spring (11), the pre-tightening spring (11) drives the pair of clamping arms (3) to have a tendency to close and rotate towards the axis direction of the outer cylinder (7).

2. A self-locking jack as claimed in claim 1, characterized in that: The pre-tightening force of the pre-tightening spring (11) makes the rotating rod (31) have a tendency to rotate towards the axis direction of the outer cylinder (7), thereby driving the clamping arm (3) to close.

3. A self-locking jack as claimed in claim 1, wherein: The base (1) is further provided with a locking cylinder (12), the cylinder body bottom of the locking cylinder (12) is rotatably connected with the base (1), and the piston rod thereof is hinged with the rotating disc (8); the axial direction of the locking cylinder (12) and the axial direction of the connecting rod (9) are staggered in space, thereby forming a lever linkage mechanism together with the locking cylinder (12), the rotating disc (8) and the connecting rod (9).

4. A self-locking jack as claimed in claim 1, wherein: The inner side of the end of each clamping arm (3) is formed with a locking chuck (32), the inner contour of the locking chuck (32) is matched with the outer cylindrical surface of the outer cylinder (7), and the end face thereof is a plane which can be engaged with the square edge of the notched tooth (71).

5. A self-locking jack as claimed in claim 4, wherein: When in the locking state, under the action of the pre-tightening spring (11), the locking chuck (32) of the clamping arm (3) is pressed and engaged below the square edge of the notched tooth (71), so as to prevent the outer cylinder (7) from falling back.

6. A self-locking jack as claimed in claim 4, wherein: When the piston rod of the locking cylinder (12) is fully extended, the rotating disc (8) is driven to rotate, and then the connecting rod (9) overcomes the pressing force of the pre-tightening spring (11) to rotate, so that the clamping arm (3) rotates to an unlocking position where the locking chuck (32) is completely separated from the notched tooth (71) of the outer cylinder (7).

7. A self-locking jack as claimed in claim 4, wherein: In the normal jacking process of the outer cylinder (7), if the locking cylinder (12) loses pressure and is in a floating state, the pre-tightening spring (11) will drive the clamping arm (3) to always maintain a closing tendency, and ensure that the locking chuck (32) can be immediately clamped below the square edge after passing a notched tooth (71), so as to realize a fault safety type passive locking.

8. A self-locking jack as claimed in claim 4, wherein: The pre-tightening spring (11) cooperates with the locking cylinder (12), and the cooperation is specifically shown as follows: in the active unlocking process, the active force is provided by the locking cylinder (12) to overcome the pre-tightening force and the load pressure of the pre-tightening spring (11); in the active locking or passive locking, the continuous compression force is provided by the pre-tightening spring (11) to eliminate the transmission gap and ensure the reliable engagement of the locking chuck (32) and the notched tooth (71).

9. A self-locking jack as claimed in claim 1, wherein: The base (1) is integrated with a hydraulic balance valve (13) for controlling the jacking speed and stability; the base (1) is further provided with a lifting socket (14) for hoisting and carrying.

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