CN112442928B

CN112442928B - A hydraulic track lifter and its usage method

Info

Publication number: CN112442928B
Application number: CN201910820858.5A
Authority: CN
Inventors: 张伟
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2025-11-04
Anticipated expiration: 2039-08-30
Also published as: CN112442928A

Abstract

This invention relates to a hydraulic track lifter and its usage method, relating to the field of railway track laying and maintenance technology. It comprises a handle, lifting lever, return spring, return valve, piston, cylinder, limit nut, locking nut, adjusting screw, hydraulic power unit, and frame. The frame has two hooks that can contact the rail jaws and apply an upward force to them. By rotating the hydraulic track lifter along the vertical axis of the rail, the hooks can move from a disengaged state to a contact state, eliminating the need for opening and closing to disengage or lock the rail head. The frame is a single unit with a more rational stress structure, higher strength, and more convenient operation.

Description

Hydraulic track jack and use method thereof

Technical Field

The invention relates to a hydraulic track lifting device and a use method thereof, which are suitable for the operation of lifting steel rails of railway ballasted lines, integral ballast bed lines and wide sleeper lines, and relate to the technical field of railway track laying and maintenance, in particular to a hydraulic track lifting device.

Background

Along with the development of railway technology to the high-speed direction, higher requirements are put forward on the smoothness of the line. The current method for adjusting the smoothness of the track in the high-low direction mainly comprises the steps of filling sand under a track bed and integrally adjusting the height of the track, is suitable for ballasted tracks, and is suitable for the integral track bed tracks, wide sleeper tracks and ballasted tracks by adding and subtracting gaskets under the tracks to adjust the smoothness of the track in the high-low direction.

The track lifting device is a special tool for adjusting the smoothness of the track in the high-low direction, and is used for lifting the whole steel rail or track bed in the process of paving and maintaining the railway track. The track jack is of a different type but mainly comprises hydraulic track jacks.

The hydraulic jack in the prior art mainly comprises a hydraulic system (comprising a motor or manual) plunger pump, a hydraulic cylinder, a hydraulic circuit, an execution component (such as a jack wheel, a jack plate and a jack hook) and the like, and the piston in the hydraulic cylinder is driven to move by the hydraulic energy provided by the hydraulic system, so that the execution component is driven to lift the proper part of a steel rail, and the purpose of jack operation is achieved. The hydraulic track jack is also provided with an oil return valve, and the hydraulic system is relieved after the operation is completed. A relief valve is also typically provided for unloading when overloaded.

The Chinese patent publication No. CN 108589445A discloses a hydraulic rail head track jack and a use method thereof. As shown in figures 1, 2 and 3. The hydraulic rail head track jack provided by the invention comprises an oil tank 1 and a base 2, wherein the oil tank 1 is arranged at the top of the base 2, the oil tank 1 is also provided with an oil filling screw plug 9, after the oil filling screw plug 9 is opened, whether the oil quantity in the oil tank 1 is sufficient or not can be observed, the base 2 is also provided with a lifting handle 10, the lifting handle 10 is used for facilitating the taking and moving of staff, the oil tank 1 is connected with a pressing hand 5, the base 2 is also provided with a manual oil return valve 6, the bottom of the base 2 is provided with a track lifting structure, and the track lifting structure is of a symmetrical double-oil-cylinder design, so that the design is one key point of small-space track lifting operation in a wide rail pillow area, on one hand, the whole volume and weight are reduced, and on the other hand, the unbalanced load condition of the conventional track jack operation is eliminated. Preferably, the track lifting structure comprises a pair of track lifting hooks 3 which are symmetrically arranged, the hook heads of the two track lifting hooks 3 are oppositely arranged, a rotating shaft is arranged on the track lifting hooks 3, the inside of the rotating shaft is communicated with an oil tank 1, hydraulic oil can be communicated with the inside of the rotating shaft, the track lifting hooks 3 are connected to the bottom of a base 2 through the rotating shaft, the track lifting hooks 3 turn outwards by 90 degrees around the rotating shaft, each track lifting hook 3 is connected with a hydraulic cylinder 4, the two hydraulic cylinders 4 are symmetrically arranged, the piston ends of the hydraulic cylinders 4 are connected with a rotatable foot 8, and when the track lifting hooks 3 turn, the hydraulic cylinders 4 are driven to switch between a vertical position and a horizontal position. The rotating shaft is provided with a positioning structure, and when the hydraulic oil cylinder 4 is positioned at a vertical position and a horizontal position, the hydraulic oil cylinder can be positioned through the positioning structure on the track lifting hook 3. The track lifting device is mainly used for track lifting operation during maintenance of the wide-track sleeper board line, and can be suitable for track lifting operation of conventional lines by being matched with the protective bottom plate, and the symmetrical structure ensures track lifting stability and safety. The track jack is placed by turning the hydraulic cylinders 4 on two sides of the track jack to keep horizontal, placing the track jack on the steel rail 11, and placing the track jack in the middle of a gap between two wide sleeper plates 12, wherein if the track jack is not positioned in the middle of the gap, the hydraulic cylinders 4 cannot be turned downwards to be in place. Referring to fig. 1, 2 and 3, the turning hydraulic cylinder keeps the track jack positioned in the middle of the gap between the two wide sleeper plates 12, and manually turns the hydraulic cylinders 4 on two sides downwards to enable the hydraulic cylinders 4 to enter a vertical state, so that the hook head of the track jack 3 hooks the lower part (rail jaw) of the rail head of the rail 11. The contact part of the two track lifting hooks 3 and the working object of the hydraulic track lifting device in the prior art is the steel rail head (more specifically, the jaw parts of the two side rails of the rail head). The prior art or the actuating component is required to be split, has an opening and closing function, can cross the rail head when being opened, can clamp the rail head when being combined, and is contacted with the rail jaw. This has some adverse effects on the use and manufacture of the hydraulic track jack.

The hydraulic track jack and the use method thereof can make up the defects in the prior art and fill the blank of the prior art.

Disclosure of Invention

The invention aims to provide a hydraulic track jack and a use method thereof, which overcome the defects of the prior art, and have the advantages of simple structure, simple and convenient operation, high stability in track jack process and high bearing capacity when track jack operation is carried out.

Further, the invention also aims to provide a hydraulic track jack and a use method thereof, which can carry out track jack operation under the condition that the distance between the bottom surface of the steel rail and the track bed is zero. Or to enhance other properties as will be mentioned later in this specification.

The above object of the present invention is achieved by the following technical solutions:

The invention provides a hydraulic track jack, which comprises a handle rod, a lifting handle, a return spring, an oil return valve, a piston, an oil cylinder, a limit nut, a lock nut, an adjusting screw, a hydraulic power unit, a frame and the like.

The frame is a basic part of the whole track jack, two groups of oil cylinders are arranged on the frame, the two groups of oil cylinders are arranged on two sides of a steel rail during operation, the frame is a whole, and two frame hooks which can be contacted with rail jaws of the steel rail and apply upward acting force to the rail jaws are arranged. By rotating the hydraulic jack along the vertical axis of the steel rail, the frame hook can be brought into contact from a state of being disengaged from the jaw. Each rack hook comprises at least a rack hook vertical face A, a rack hook vertical face B and a rack hook inclined face. The rack hook vertical faces A on two sides are symmetrically distributed relative to the symmetry plane of the rack hook vertical face A. The rack hook vertical faces B on two sides are symmetrically distributed relative to the symmetry plane of the rack hook vertical face B. When the symmetry plane of the vertical face A of the rack hook is coincident with the longitudinal symmetry plane of the steel rail, a gap more than or equal to 0 is reserved between the vertical face A of the rack hook and the rail head of the steel rail. An included angle alpha exists between the rack hook vertical face A and the rack hook vertical face B, and the same included angle alpha exists between the symmetrical surface of the rack hook vertical face A and the symmetrical surface of the rack hook vertical face B. The frame rotates around the vertical axis of the steel rail by an included angle alpha, the symmetrical surface of the frame hook vertical surface B of the frame coincides with the longitudinal symmetrical surface of the steel rail, and a gap more than or equal to 0 is arranged between the frame hook vertical surface B and the steel rail head. Meanwhile, the included angle of the inclined planes C of the two rack hook parts is consistent with the included angle of the rail jaw of the steel rail.

The hydraulic power unit is arranged on the frame, the handle rod is arranged on the hydraulic power unit, the handle rod is rocked, the hydraulic power unit can input hydraulic oil into the oil cylinder, and the hydraulic power unit is provided with a safety valve for limiting the highest pressure of the hydraulic system.

The frame is provided with an oil cylinder, a piston is arranged in the oil cylinder, the lower end part of the oil cylinder is provided with a limit nut, the lower end part of the limit nut is provided with a section of outer cylindrical surface, the piston outputs the acting force of lifting channels under the drive of hydraulic oil, the limit nut can limit the working stroke of the piston, the outer cylindrical surface of the lower end part of the limit nut can limit the rotation angle of the hydraulic track jack around the vertical axis of the steel rail through the contact with the side surface of the rail bottom of the steel rail, so that the two frame hook parts and the rail jaw of the steel rail can keep the correct contact position.

An oil return valve is arranged on the frame, the oil return valve is opened, and the piston is reset under the action of a reset spring.

The lower end of the piston is provided with a locking nut and an adjusting screw rod which are combined through threads, the locking nut and the adjusting screw rod can be detached from the piston, the adjusting screw rod can be screwed out of the piston for a section, the upper end of the locking nut is in an outer cone shape and is matched with the inner cone shape of the lower end of the piston, and the purpose of locking the piston and the adjusting screw rod is achieved after the locking nut is screwed down.

The hydraulic track lifting device also comprises a lifting handle, one end of the lifting handle is slightly inclined upwards, and the other end of the lifting handle is slightly inclined downwards, so that the hydraulic track lifting device meets the ergonomic requirement that the tiger mouth end is slightly higher than the little finger end when people lift heavy things, and is more convenient to operate and carry through the arrangement.

From the above, the hydraulic track jack provided by the invention has the advantages of reasonable and compact structure, safety, reliability, high operation efficiency, convenience in operation and carrying, and high degree of freedom in an adjusting range, and can particularly perform track jack or track jack operation under the working condition that the distance between the bottom surface of a steel rail and a track bed is zero.

Drawings

The present disclosure will become more apparent with reference to the accompanying drawings. It should be understood that these drawings are illustrative only and are not drawn to scale and are not intended to limit the scope of the invention. In the figure:

FIG. 1 is a prior art hydraulic rail head jack and method of using the same;

FIG. 2 is an initial state of the art hydraulic rail head jack and method of use thereof;

FIG. 3 is an operational state of a hydraulic rail head jack and method of use thereof in the prior art;

FIG. 4 is a front view of an embodiment of a hydraulic track jack and method of use thereof according to the present invention when the track jack is in the starting state of the track jack;

FIG. 5 is a left side view of an embodiment of a hydraulic track jack and method of using the same according to the present invention when the track jack is in a start state of a track jack operation;

FIG. 6 is a right side view of an embodiment of a hydraulic track jack and method of use thereof in accordance with the present invention when the track jack is in the starting state of a track jack;

FIG. 7 is a top view of a hydraulic track jack and method of use thereof according to an embodiment of the present invention when the track jack is in a start state of a track jack operation;

FIG. 8 is a bottom view of a hydraulic track jack and method of using the same according to an embodiment of the present invention when the track jack is in a start state of a track jack operation;

FIG. 9 is a schematic perspective view of a hydraulic track jack and method of use thereof according to an embodiment of the present invention when the track jack is in a starting state for a track jack operation;

FIG. 10 is a front view of a hydraulic track jack and method of using the same according to an embodiment of the present invention when the track jack is in an operational state for track jack operation;

FIG. 11 is a left side view of a hydraulic track jack and method of use thereof according to an embodiment of the present invention when the track jack is in an operational state for track jack operation;

FIG. 12 is a right side view of a hydraulic track jack and method of use thereof according to an embodiment of the present invention when the track jack is in an operational state for track jack operation;

FIG. 13 is a top view of a hydraulic track jack and method of use thereof according to an embodiment of the present invention when the track jack is in an operational state for track jack operation;

FIG. 14 is a bottom view of a hydraulic track jack and method of using the same according to an embodiment of the present invention when the track jack is in an operational state for track jack operation;

FIG. 15 is a schematic perspective view of a hydraulic track jack and method of use thereof according to an embodiment of the present invention when the track jack is in an operational state for track jack operation;

FIG. 16 is a second front view of a hydraulic jack and method of use thereof according to the present invention, with the jack in an operational state for jack operation, with the lock nut and 190 adjustment screw removed 180, and with jack operation performed with zero rail bottom to bed spacing;

FIG. 17 is a third front view of a hydraulic jack and method of use according to the present invention, wherein when the jack is in the working state of the jack, the 190 adjustment screw is screwed out of the 150 pistons for a distance and then locked by the locking nut 180, so that the jack can be operated under the working condition that the distance between the bottom surface of the rail and the track bed is large, or on the road section that the distance between the bottom surface of the rail and the track bed is relatively consistent, thereby achieving the purposes of reducing the idle stroke and improving the working efficiency;

Fig. 18 is a front view of the frame 210 of a hydraulic jack and a method of using the same according to the present invention, which shows the geometry of the frame 210 in the front view direction, and also shows the positional relationship between the frame 210 and the rail 220 when the jack is in the start state of the jack;

Fig. 19 is a top view of a frame 210 of a hydraulic jack and method of use thereof according to the present invention, the diagram representing the geometry of the frame 210 in the top view direction, while expressing the hydraulic oil passages required for the hydraulic power unit 200 to be disposed within the frame 210;

FIG. 20 is a bottom view of a frame 210 of a hydraulic jack and method of use thereof according to the present invention;

FIG. 21 is a B-B cross-sectional view of FIG. 18 showing a hydraulic track jack and method of use thereof in accordance with the present invention;

Fig. 22 is a schematic perspective view of a frame 210 of a hydraulic track jack and method of using the same in accordance with the present invention.

Fig. 23 is a schematic perspective view of a frame 210 of a hydraulic jack and a method of using the same according to the present invention, which shows the structure of a frame hook 2101.

The invention relates to a hydraulic track jack and a part and a label list of a using method thereof.

Detailed Description

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The description is intended to be illustrative and exemplary only.

Fig. 4 is a front view of an embodiment of a hydraulic jack and method of using the same according to the present invention. As shown in the drawing, the hydraulic jack 100 mainly includes a handle bar 110, a handle bar 120, a return spring 130, an oil return valve 140, a piston 150, an oil cylinder 160, a limit nut 170, a lock nut 180, an adjusting screw 190, a hydraulic power unit 200, a frame 210, and the like.

Referring to fig. 4, a hydraulic power unit 200 is installed on a frame 210, a handle bar 110 is installed on the hydraulic power unit 200, the handle bar 110 is rocked, the hydraulic power unit 200 can input hydraulic oil into an oil cylinder 160, and a safety valve for limiting the highest pressure of a hydraulic system is arranged in the hydraulic power unit 200.

Referring to fig. 17, an oil cylinder 160 is installed on a frame 210, a piston 150 is installed in the oil cylinder 160, a limit nut 170 is installed at the lower end of the oil cylinder 160, the piston 150 outputs a lifting force under the driving of hydraulic oil, and the limit nut 170 can limit the working stroke of the piston 150.

Referring to fig. 8 and 14, the cylinder 160 is mounted on the frame 210, the piston 150 is mounted in the cylinder 160, the limit nut 170 is mounted at the lower end of the cylinder 160, a section of outer cylindrical surface is provided at the lower end of the limit nut 170, and the outer cylindrical surface at the lower end of the limit nut 170 can limit the rotation angle of the hydraulic jack around the vertical axis 2201 of the steel rail by contacting with the rail bottom side of the steel rail 220, so as to ensure that the two frame hooks 2101 and the rail jaw of the steel rail 220 maintain a correct contact position.

Referring to fig. 10, the oil return valve 140 is mounted on the frame 210, and the piston 150 is reset by the reset spring 130 by opening the oil return valve 140.

Referring to fig. 16 and 17, a lock nut 180 and an adjusting screw 190 are mounted at the lower end of the piston 150, and are combined by threads, so that they can be removed from the piston, the adjusting screw 190 can be screwed out of the piston 150, the upper end of the lock nut 180 is in an outer cone shape, and the lock nut 180 is matched with the inner cone shape of the lower end of the piston 150, so that the purpose of locking the piston 150 and the adjusting screw 190 is achieved after the lock nut 180 is screwed.

The hydraulic track jack also comprises the lifting handle 120, one end of the lifting handle 120 is slightly inclined upwards, and the other end of the lifting handle 120 is slightly inclined downwards, so that the hydraulic track jack meets the ergonomic requirement that the tiger mouth is slightly higher than the little finger end when people lift heavy things, and is more convenient to operate and carry through the arrangement. In alternative embodiments, the handle 120 may also be sheathed with a jacket of a suitable material, shape, to increase comfort. Through the arrangement, the hydraulic track jack is more convenient to operate and carry.

Referring to fig. 4, 10, 18, 19, 20, 21 and 22, the frame 210 is a base member of the whole track jack, the frame 210 is a whole, and two frame hooks 2101 capable of contacting with jaws of the steel rail 220 and applying upward force to the jaws are provided at the lower part. The frame hook 2101 can be brought into contact from the disengaged state with the jaw by rotating the hydraulic jack along the rail vertical axis 2201. I.e. from the state of fig. 4 to the state of fig. 10. Each rack hook 2101 comprises at least a rack hook elevation a21011, a rack hook elevation B21012, and a rack hook incline C21013. The rack hook vertical faces A21011 on two sides are symmetrically distributed relative to the symmetrical plane 210111 of the rack hook vertical face A. The rack hook vertical faces B21012 on two sides are symmetrically distributed relative to the symmetrical plane 210121 of the rack hook vertical face B. Referring to fig. 18, when the symmetry plane 210111 of the rack hook vertical face a coincides with the longitudinal symmetry plane 2202 of the rail, a gap with delta equal to or greater than 0 is formed between the rack hook vertical face a21011 and the rail head 220 of the rail, and preferably, the delta is preferably 1-10 mm. Referring to fig. 21, an included angle α exists between the rack hook vertical face a21011 and the rack hook vertical face B21012, and the same included angle α also exists between the symmetry plane 210111 of the rack hook vertical face a and the symmetry plane 210121 of the rack hook vertical face B. Referring to fig. 22, the frame 210 rotates around the vertical axis 2201 of the steel rail by an included angle α, the symmetry plane 210121 of the frame hook vertical face B of the frame 210 coincides with the longitudinal symmetry plane 2202 of the steel rail, and a gap epsilon is more than or equal to 0 between the frame hook vertical face B21012 and the rail head of the steel rail 220, preferably epsilon is in a range of 1-10 mm. Meanwhile, the included angle of the two rack hook inclined planes C21013 is consistent with the included angle of the rail jaw of the steel rail 220, and is beta.

As can be seen from the above description, when the jack is performed, the operator can place the head of the rail 220 between the two rack hook vertical faces a21011 by merely adjusting the symmetry plane 210111 of the rack hook vertical face a of the hydraulic jack 100 to approximately coincide with the rail longitudinal symmetry plane 2202, see fig. 4 and 18. The operator rotates the hydraulic jack 100 around the vertical axis 2201 by an included angle α, the symmetry plane 210121 of the vertical plane B of the frame hook portion of the frame 210 coincides with the vertical symmetry plane 2202 of the rail, see fig. 14, at this time, the outer cylindrical surface of the lower end portion of the limit nut 170 contacts with the rail bottom side surface of the rail 220, which just ensures that the angle α of rotation of the hydraulic jack around the vertical axis 2201 of the rail, and ensures that the two frame hook portions 2101 maintain a correct contact position with the rail jaw of the rail 220. Because the clearance epsilon is more than or equal to 0 between the rack hook vertical face B21012 and the rail head of the steel rail 220, the rail head of the steel rail 220 is clamped between the two rack hooks 2101, and because the included angle of the two rack hook inclined faces C21013 is consistent with the included angle of the rail jaw of the steel rail 220 and is beta, the rack hook inclined faces C21013 can be well matched with the rail jaw part of the steel rail 220, and the track lifting operation is facilitated, as shown in fig. 10 and 22. Referring to fig. 10, when the handle bar 110 is swung, the hydraulic power unit 200 can input hydraulic oil into the oil cylinder 160, and a safety valve for limiting the highest pressure of the hydraulic system is arranged in the hydraulic power unit 200, when the track lifting load exceeds the rated track lifting force of the hydraulic track lifting device 100, the hydraulic system is unloaded, and the purpose of protecting the hydraulic track lifting device 100 and a circuit is achieved. Under normal load, the hydraulic oil drives the piston 150 in the oil cylinder 160 to extend outwards, the ballast bed 230 is used as a support, the lifting acting force is output, and the limit nut 170 can limit the working stroke of the piston 150. In particular, see FIG. 16, In fig. 17, the lower end of the piston 150 is provided with a lock nut 180 and an adjusting screw 190 which are combined through threads, and can be removed from the piston, so that the hydraulic track jack 100 can perform track jack operation under the working condition that the distance between the bottom surface of a steel rail and a track bed is smaller or zero, the adjusting screw 190 can be screwed out of the piston 150 for one section, the upper end of the lock nut 180 is in an outer cone shape and is matched with the inner cone shape of the lower end of the piston 150, after the lock nut 180 is screwed, the piston 150 and the adjusting screw 190 are locked, and track jack operation can be performed under the working condition that the distance between the bottom surface of the steel rail and the track bed is larger, or track jack operation can be performed on the section where the distance between the bottom surface of the steel rail and the track bed is more consistent, so that the idle stroke is reduced and the working efficiency is improved. After the completion of the channeling step, referring to fig. 10, the oil return valve 140 is installed on the frame 210, the oil return valve 140 is opened, and the piston 150 is restored under the action of the restoring spring 130. The operator then rotates the entire hydraulic jack 100 about the rail vertical axis 2201 at an angle α in the opposite direction from the start, thereby returning the hydraulic jack 100 to the state of fig. 4. The hydraulic jack 100 is removed from the rail 220 and a jack is completed.

As described above, exemplary embodiments of the present application are described in detail with reference to the accompanying drawings. It should be understood that the application is not intended to be limited to these specific details as set forth in the following description. Equivalent or similar changes to the structure and features of the exemplary embodiments may be made without departing from the spirit and scope of the present application, which changes will also fall within the protection scope of the application as defined in the appended claims.

Claims

1. A hydraulic track jack, characterized in that it comprises a handle rod, a lifting handle, a return spring, a return valve, a piston, a cylinder, a limit nut, a locking nut, an adjusting screw, a hydraulic power unit, and a frame. The frame is an integral unit with two hooks that can contact the rail jaws and apply an upward force to the rail jaws. By rotating the hydraulic track jack as a whole along the vertical axis of the rail, the hooks can move from a disengaged state to a contact state with the rail jaws. Each hook includes at least a hook face A, a hook face B, and a hook inclined face C. The hook faces A on both sides are symmetrically distributed with respect to the hook faces A. The symmetrical faces of the frame hook face A and the frame hook face B are symmetrically distributed. When the symmetrical face of the frame hook face A coincides with the longitudinal symmetrical face of the rail, there is a gap of ≥0 between the frame hook face A and the rail head. There is an angle α between the frame hook face A and the frame hook face B. Similarly, there is also the same angle α between the symmetrical faces of the frame hook face A and the frame hook face B. When the frame is rotated around the vertical axis of the rail by an angle α, the symmetrical face of the frame hook face B will coincide with the longitudinal symmetrical face of the rail. There is a gap of ≥0 between the frame hook face B and the rail head. At the same time, the angle between the two inclined faces C of the frame hook face is the same as the angle between the rail jaws.

2. The hydraulic track lifter as described in claim 1, characterized in that the frame is the basic component of the entire track lifter, on which two sets of hydraulic cylinders are installed, and during operation, the two sets of hydraulic cylinders are arranged on both sides of the rail.

3. The hydraulic track lifter as described in claim 1, characterized in that a cylinder is installed on the frame, a piston is installed in the cylinder, a limit nut is installed at the lower end of the cylinder, the piston outputs a track lifting force under the drive of hydraulic oil, the limit nut can limit the working stroke of the piston, and the lower end of the limit nut is provided with an outer cylindrical surface. The outer cylindrical surface at the lower end of the limit nut can limit the angle of rotation of the hydraulic track lifter around the vertical axis of the rail by contacting the side of the bottom of the rail, ensuring that the hooks of the two frames maintain the correct contact position with the rail jaws.

4. The hydraulic lifting device as described in claim 1, characterized in that one end of the handle is slightly tilted upward and the other end of the handle is slightly tilted downward, which meets the ergonomic requirement that the tiger's mouth end is slightly higher than the little finger end when a person lifts a heavy object.

5. The hydraulic track lifter as described in claim 1, characterized in that a locking nut and an adjusting screw are installed at the lower end of the piston, which are connected by threads and can be removed from the piston, or the adjusting screw can be screwed out of the piston. The upper end of the locking nut is outwardly conical, which cooperates with the inner conical shape of the lower end of the piston. After tightening the locking nut, the piston and the adjusting screw are locked.

6. A method of using a hydraulic track lifter as described in any one of claims 1 to 5, characterized in that it comprises:

1) During track lifting operations, the operator only needs to adjust the symmetrical plane of the hook face A of the hydraulic track lifter frame to coincide with the longitudinal symmetrical plane of the rail. The rail head can then be placed between the two hook faces A of the frame. The operator then rotates the entire hydraulic track lifter around the vertical axis of the rail by an included angle α. The symmetrical plane of the hook face B of the frame will then coincide with the longitudinal symmetrical plane of the rail. At this time, the outer cylindrical surface of the lower end of the limit nut, through contact with the side of the rail bottom, ensures that the angle of rotation of the hydraulic track lifter around the vertical axis of the rail is α. This ensures that the two hook faces of the frame and the rail jaws of the rail maintain the correct contact position, and the rail head of the rail is locked between the two hook faces of the frame. The inclined surface C of the hook face of the frame can fit well with the rail jaws of the rail, which is beneficial to the track lifting operation.

2) Crank the handle lever, and the hydraulic power unit inputs hydraulic oil into the oil cylinder. Under normal load, the hydraulic oil drives the piston in the oil cylinder to extend outward, supporting the track bed and outputting the lifting force. The limit nut can limit the working stroke of the piston. When the load exceeds the rated lifting force of the hydraulic track lifter, the safety valve built into the hydraulic power unit will unload the hydraulic system to protect the hydraulic track lifter and the line.

3) After the track lifting step is completed, the return oil valve is installed on the frame. Open the return oil valve and the piston will be reset under the action of the return spring. Then the operator will rotate the hydraulic track lifter around the vertical axis of the rail in the opposite direction of rotation by an included angle α, and the hydraulic track lifter can be removed from the rail, thus completing one track lifting operation.

7. The method of using a hydraulic track lifter as described in claim 6, characterized in that a locking nut and an adjusting screw are installed at the lower end of the piston, which are connected by threads and can be removed from the piston, so that the hydraulic track lifter can perform track lifting operations when the distance between the bottom surface of the rail and the track bed is small or zero.

8. The method of using a hydraulic track lifter as described in claim 6, characterized in that a locking nut and an adjusting screw are installed at the lower end of the piston. They are connected by threads, and the adjusting screw can be screwed out of the piston by a certain distance. After tightening the locking nut, the piston and the adjusting screw can be locked. Track lifting operations can be carried out when the distance between the bottom surface of the rail and the track bed is large, or when track lifting operations are carried out on sections where the distance between the bottom surface of the rail and the track bed is relatively uniform, and the idle stroke of the piston can be reduced.