Hydraulic pile cutting device unit and using method thereof

Abstract

The invention discloses a hydraulic pile cutting device unit and a using method thereof. The hydraulic pile cutting device unit comprises a steel chisel, a guide base, a movable base, a hydraulic telescopic device, a force transmission device and a one-way moving device. The steel chisel is a cylinder and is provided with a plurality of annular wedge-shaped tooth sockets; the guide base comprises a cylindrical main body, a guide hole is formed in the cylindrical main body in the axial direction, the steel chisel is arranged in the guide hole, and the hydraulic telescopic device is arranged on the cylindrical main body; the one-way moving device comprises a plurality of first limiting valves and second limiting valves. According to the hydraulic pile cutting device unit, a hydraulic telescopic device and a steel chisel are arranged on the upper layer and the lower layer, and the length of the hydraulic pile cutting device unit can be reduced; and moreover, the hydraulic telescopic device stretches out and draws back for many times to achieve movement of the steel chisel, the short-stroke hydraulic telescopic device can be selected, the length of the hydraulic pile cutting device unit is further reduced, and the hydraulic pile cutting device adapts to a construction site with small pile spacing.

Description

Technical Field

[0001] The invention relates to a hydraulic pile cutting device unit and a use method thereof, belonging to the technical field of underground pile foundations. Background Art

[0002] Concrete cast-in-place piles are a common type of pile foundation, widely used in various construction and infrastructure projects. During the construction of concrete cast-in-place piles, a certain height is often overfilled, and the overfilled part is cut before connecting to the superstructure to ensure the connection quality between the pile foundation and the superstructure. The overfilled part is called the pile head. The traditional pile head processing process usually uses tools such as pneumatic picks to chisel or cut off the pile head manually, and then lift it away with a crane. This has many disadvantages, such as high man-machine investment costs, high construction safety risks, and low mechanization levels.

[0003] At present, some companies have developed simple hydraulic pile cutting devices on the market, which are equipped with several hydraulic devices arranged in a ring. The ends of the hydraulic devices are equipped with steel chisels pointing to the center point of the ring. The hydraulic devices drive the steel chisels to extend and retract to cut the pile. However, when the hydraulic cylinder and the pile cutting chisel are arranged in the same plane, the size of the hydraulic pile cutting device will be too large. For example, if the diameter of the pile is 1m, the diameter of the hydraulic pile cutting device must be more than 3m. In construction sites with small pile spacing, the hydraulic pile cutting device will not be able to enter the construction site. Summary of the invention

[0004] In view of the problem existing in the co-planar arrangement of the existing hydraulic cylinder and the pile-cutting steel chisel, the present invention provides a hydraulic pile-cutting device unit and a method of using the same. By arranging the hydraulic cylinder and the pile-cutting steel chisel in layers, the size of the hydraulic pile-cutting device unit constituting the hydraulic pile-cutting device is greatly reduced, thereby being able to adapt to the construction environment of narrow pile spacing.

[0005] In order to solve the above technical problems, the present invention includes the following technical solutions:

[0006] A hydraulic pile cutting device unit comprises a steel drill, a guide base, a movable seat, a hydraulic telescopic device, a force transmission device and a one-way moving device;

[0007] The steel chisel is a cylinder with a pointed tip at one end, and a plurality of annular wedge-shaped tooth sockets are arranged on the cylinder;

[0008] The guide base comprises a cylindrical body, a guide hole is arranged in the cylindrical body along the axial direction, a steel drill is arranged in the guide hole, a tip of the steel drill is located at the front end of the cylindrical body, and a tail of the steel drill extends out of the rear end of the cylindrical body; a hollow part is arranged on the cylindrical body;

[0009] The movable seat is arranged at the tail of the guide base, a through hole is arranged in the middle and is sleeved on the tail of the steel drill;

[0010] The one-way moving device includes a plurality of first limit valves and second limit valves, wherein the first limit valves are arranged on the movable base, and the second limit valves are arranged on the hollow part of the cylindrical body, and the first limit valves and the second limit valves are both connected with the steel drill tooth groove buckle to prevent the steel drill from moving backward;

[0011] The hydraulic telescopic device is arranged on the cylindrical main body, and the force transmission device can transmit the displacement of the telescopic end of the hydraulic telescopic device to the movable seat. The telescopic movement of the hydraulic telescopic device can drive the movable seat to move forward and backward; when the movable seat moves forward, the first limit valve clamps the steel drill groove and pushes the steel drill forward. When the movable seat moves backward, the second limit valve clamps the steel drill groove and keeps the steel drill stationary.

[0012] Furthermore, a first hinge fulcrum is provided at the top of the rear end of the cylindrical body, and a second hinge fulcrum is provided at the bottom of the front end of the cylindrical body;

[0013] The force transmission device includes two power levers, a power pin and two straight connecting rods; a power lever is arranged on each side of the cylindrical body, the bottom of the power lever is hinged to the second hinge fulcrum, and the tops of the two power levers are respectively hinged to the ends of the power pin; one end of the straight connecting rod is hinged to the middle of the power lever, and the other end is hinged to the movable seat;

[0014] One end of the hydraulic telescopic device is hinged to the first hinge fulcrum, and the other end is hinged to the power pin shaft.

[0015] Furthermore, the first limit valve and the second limit valve both include a pin shaft, a limit plate and a torsion spring. One end of the limit plate is sleeved on the pin shaft, and the torsion spring is arranged on the pin shaft. The pin shaft of the first limit valve is arranged on the movable seat, and the pin shaft of the second limit valve is arranged on the cylindrical body. The torsion spring causes the end of the limit plate to press the steel chisel and press against the annular wedge-shaped tooth groove.

[0016] Furthermore, both sides of the front end of the cylindrical body are provided with horizontal first threaded holes, and the rear end of the cylindrical body is provided with horizontal second threaded holes;

[0017] The first threaded hole is provided with a first hinged head screw, and the second threaded hole is provided with a second hinged head screw;

[0018] The first hinged joint screw rod comprises a first threaded rod and a first connecting ring arranged at one end of the first threaded rod; the first threaded rod is threadedly connected with the first threaded hole;

[0019] The second hinged joint screw rod comprises a second threaded rod and a second connecting ear plate arranged at one end of the second threaded rod; the second threaded rod is threadedly connected with the second threaded hole.

[0020] Accordingly, the present invention also provides a method for using the hydraulic pile cutting device unit, comprising the following steps:

[0021] Step 1: In the initial state, the hydraulic expansion and contraction device is in a contracted state, and the first limit valve and the second limit valve limit the steel drill tooth groove in one direction;

[0022] Step 2: The hydraulic telescopic device is extended, the force transmission device pulls the movable seat forward, and the steel drill moves forward synchronously with the first limit valve by M tooth socket spacings, and the second limit valve does not hinder the steel drill from moving forward, where M is a preset value, M≥1;

[0023] Step 3: The hydraulic expansion and contraction device is operated, the force transmission device pulls the movable seat to move backward, the first limit valve is synchronously moved backward by M tooth socket spacings, the second limit valve performs one-way limit on the steel drill tooth socket, and the position of the steel drill remains unchanged;

[0024] Step 4: Repeat steps 2 and 3 to gradually move the steel drill forward.

[0025] Due to the adoption of the above technical scheme, the present invention has the following advantages and positive effects compared with the prior art: the hydraulic pile cutting device unit provided by the present invention sets the hydraulic telescopic device and the steel drill into two layers, which can reduce the length of the hydraulic pile cutting device unit; moreover, the hydraulic telescopic device is telescoped for multiple times to realize the movement of the steel drill to complete the pile cutting, and the hydraulic telescopic device only moves a short distance each time, so a short-stroke hydraulic telescopic device can be selected to further reduce the length of the hydraulic pile cutting device unit; in addition, the displacement of the hydraulic telescopic device is transmitted to the second steel drill limit valve seat through the force transmission device, and the power lever can be used to amplify the force of the hydraulic telescopic device, so that a low-power hydraulic telescopic device can be selected. Therefore, the hydraulic pile cutting device unit provided by this embodiment has a smaller radius, can adapt to construction sites with smaller pile spacing, and can reduce costs by selecting a short-stroke, low-power hydraulic telescopic device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a hydraulic pile cutting device unit in one embodiment of the present invention;

[0027] Figure 2 It is a structural schematic diagram of a steel drill in one embodiment of the present invention;

[0028] Figure 3 It is a schematic structural diagram of a limit guide base and a second limit valve in one embodiment of the present invention;

[0029] Figure 4 It is a structural schematic diagram of a movable seat and a first limit valve in one embodiment of the present invention;

[0030] Figure 5 It is a structural schematic diagram of a hydraulic telescopic device in one embodiment of the present invention;

[0031] Figure 6It is a structural schematic diagram of a power lever in one embodiment of the present invention;

[0032] Figure 7 is a schematic structural diagram of a straight connecting rod in one embodiment of the present invention;

[0033] Figure 8 It is a schematic diagram of eight hydraulic pile cutting device units spliced ​​together to form a hydraulic pile cutting device in one embodiment of the present invention;

[0034] Fig. 9 Schematic diagram of the structure of a first articulated joint screw and a second articulated joint screw in one embodiment of the present invention.

[0035] The numbers in the figure are as follows:

[0036] 1-Hydraulic pile cutting device unit;

[0037] 10-steel chisel; 11-tip; 12-tooth socket;

[0038] 20-guide base; 21-cylindrical body; 22-guide hole; 23-first hinge fulcrum; 24-second hinge fulcrum;

[0039] 30- hydraulic telescopic device; 31- hydraulic cylinder; 32- telescopic rod;

[0040] 40-force transmission device; 41-power lever; 411-first hinge node; 412-second hinge node; 413-third hinge node; 42-power pin shaft; 43-straight connecting rod;

[0041] 50-movable seat; 51-third hinge fulcrum;

[0042] 60-one-way moving device; 61-first limit valve; 62-second limit valve;

[0043] 70 - splicing and fixing device; 71 - first articulated screw rod; 72 - second articulated screw rod. DETAILED DESCRIPTION

[0044] The following is a further detailed description of a hydraulic pile cutting device unit and a method of using the same provided by the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer in conjunction with the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0045] Embodiment 1

[0046] like Figure 1As shown, a hydraulic pile cutting device unit provided in this embodiment includes a steel chisel 10, a guide base 20, a hydraulic telescopic device 30, a force transmission device 40, a movable seat 50 and a one-way moving device 60.

[0047] Combination Figure 1 and Figure 2 As shown, the steel drill 10 is a cylinder with a tip 11 at one end, the tip 11 is used to squeeze the pile body, and a plurality of annular wedge-shaped tooth sockets 12 are arranged on the cylinder. As an example, the tip of the steel drill 10 is a cone, and the cylinder is a long cylinder, such as a cylinder with a length of 40 cm and a diameter of 5 cm. The annular wedge-shaped tooth sockets 12 are arranged at equal intervals along the circumference of the cylinder, and the groove section is a right triangle, one side is a groove slope surface, and the other side is a groove end surface, and the groove slope surface faces the tip of the steel drill 10, such as a groove depth of 10 mm, a groove length of 20 mm, and a groove distance of 35 mm.

[0048] Combination Figures 1 to 3 As shown, the guide base 20 includes a cylindrical body 21, and a guide hole 22 is axially arranged in the cylindrical body 21. The steel drill 10 is arranged in the guide hole 22 of the limiting guide base 20, and cooperates with the unidirectional moving device 60 to realize unidirectional movement along the guide hole 22. The tip of the steel drill 10 is located at the front end of the cylindrical body 21, and the tail of the steel drill 10 extends out of the rear end of the cylindrical body 21. The guide hole 22 of the cylindrical body 21 is mainly used to place the steel drill 10 and guide the steel drill 10. As an example, the guide hole 22 is slightly larger than the outer diameter of the steel drill 10, such as about 1mm. The steel drill 10 is arranged in the guide hole 22, and the cylindrical body 21 can be hollowed out. A first hinge fulcrum 23 is arranged at the top of the rear end of the cylindrical body 21, and the first hinge fulcrum 23 is used to be hinged with one end of the hydraulic telescopic device 30. A second hinge fulcrum 24 is provided at the bottom of the front end of the cylindrical body 21 , and the second hinge fulcrum 24 is used for hinge connection with a power lever described below.

[0049] Combination Figure 1 and Figure 4 As shown, the movable seat is a circular ring plate, and the through hole in the middle is used to be sleeved on the steel chisel. A third hinge fulcrum 51 is provided on the movable seat for hinge connection with the force transmission device 40.

[0050] Combination Figure 1 and Figure 5 As shown, one end of the hydraulic telescopic device 30 is hinged to the first hinge fulcrum 23, and the other end is hinged to the force transmission device 40. The hydraulic telescopic device 30 generally includes a hydraulic cylinder 31 and a telescopic rod 32, and the extension and contraction of the telescopic rod 32 can be remotely controlled. The hydraulic telescopic device 30 can adopt existing technology, which will not be described here. The specific connection method between the hydraulic cylinder 31 and the first hinge fulcrum 23 can be provided by providing a connecting ear plate, a pin hole is provided on the ear plate, and the connection is made through a pin shaft, and other hinge methods can also be adopted.

[0051] Combination Figure 1 , Figures 3 to 7 As shown, the force transmission device 40 mainly transmits the force and displacement of the telescopic rod of the hydraulic telescopic device 30 to the movable seat 50, and the specific structure of the force transmission device can be set as needed. As an example, the force transmission device 40 includes a power lever 41, a power pin 42 and a straight connecting rod 43. The power lever 41 is a rod body or a plate-shaped rod, and three hinge nodes are arranged at intervals along the length direction on the power lever 41, which are marked as the first hinge node 411, the second hinge node 412 and the third hinge node 413 from bottom to top. A power lever 41 is arranged on each side of the cylindrical body 21, and the first hinge node 411 of the power lever 41 is hingedly arranged with the second hinge fulcrum 24. A power pin 42 is arranged in the third hinge node 413 of the two power levers 41, and one end of the hydraulic telescopic device 30 is hinged with the power pin 42, for example, a pin hole is arranged at the end of the telescopic rod, and the telescopic rod is sleeved on the power pin through the pin hole. A straight connecting rod 43 is provided on each side of the cylindrical body 21, one end of the straight connecting rod 43 is hinged to the second hinge node 412 of the power lever 41, and the other end is hinged to the third hinge fulcrum of the movable seat. When the hydraulic telescopic device 30 is extended or retracted, the power lever 41 rotates around the first hinge node 411 and drives the straight connecting rod 43 to move forward and backward, and the straight connecting rod drives the movable seat to move synchronously.

[0052] Combination Figures 1 to 4 As shown, the one-way moving device 60 includes a plurality of first limit valves 61 and a plurality of second limit valves 62. Both the first limit valve 61 and the second limit valve 62 limit the steel drill 10 in one direction, that is, prevent the steel drill 10 from moving backward and allow the steel drill 10 to move forward. As an example, the first limit valve 61 is arranged on the movable seat 50, and the second limit valve 62 is arranged on the cylindrical body 21. The first limit valve 61 and the second limit valve 62 are structurally the same, and both include a pin shaft, a limit plate and a torsion spring. The limit plate is fan-shaped and is installed on the movable seat or the cylindrical body 21 through a pin shaft hinge node and can rotate around the pin shaft. The torsion spring is arranged on the pin shaft and applies a force to the limit plate, and the force causes the end of the limit plate to press the steel drill 10 and press against the annular wedge-shaped tooth groove 12. The cylindrical body 21 is hollowed out, and the second limit valve 62 is arranged in the hollow part of the cylindrical body 21. The second limit valve 62 is arranged to have the same structure as the first limit valve 61, which can reduce the number of standard parts. As an example, three first limit valves 61 and two limit valves 62 are arranged, and are arranged around the steel drill.

[0053] The hydraulic pile cutting device unit 1 provided in this embodiment sets the hydraulic telescopic device 30 and the steel drill 10 in two layers, which can reduce the length of the hydraulic pile cutting device unit 1; moreover, the hydraulic telescopic device 30 is telescoped multiple times to realize the forward movement of the steel drill 10, and the hydraulic telescopic device 30 only moves a short distance each time, so a short-stroke hydraulic telescopic device 30 can be selected to further reduce the length of the hydraulic pile cutting device unit 1; in addition, the displacement of the hydraulic telescopic device 30 is transmitted to the movable seat through the force transmission device 40, and the power lever 41 can be used to amplify the force of the hydraulic telescopic device 30, so that a low-power hydraulic telescopic device 30 can be selected. Therefore, the hydraulic pile cutting device unit provided in this embodiment has a smaller length, can adapt to the construction site with a small pile spacing, and the equipment cost can be reduced by selecting a short-stroke, low-power hydraulic telescopic device 30.

[0054] Figure 8 The schematic diagram of splicing together eight hydraulic pile cutting device units 1 to form a hydraulic pile cutting device is shown, and adjacent hydraulic pile cutting device units 1 are spliced ​​and fixed by a splicing and fixing device 70, which can improve the splicing efficiency. The specific structure of the splicing and fixing device 70 can be set as required, for example, connecting ear plates are set on both sides of the cylindrical body 21, and the connecting ear plates of adjacent hydraulic pile cutting device units 1 are spliced ​​and fixed by pins. Figure 8 A more adaptable splicing and fixing device 70 is shown in the figure. The splicing and fixing device 70 includes two first hinge screw rods 71 ​​and two second hinge screw rods 72. The first hinge screw rod 71 includes a first threaded rod and a first connecting ring arranged at one end of the first threaded rod, and the second hinge screw rod 72 includes a second threaded rod and a second connecting ring arranged at one end of the second threaded rod. In order to cooperate with the first hinge screw rod 71 and the second hinge screw rod 72, a horizontal first threaded hole is arranged on both sides of the rear end of the cylindrical body 21, such as the first hinge fulcrum 23 is a horizontally arranged round tube with internal threads, which also serves as a threaded hole, and a horizontal second threaded hole is arranged on both sides of the front end of the cylindrical body 21, such as the second hinge fulcrum 24 is a horizontally arranged round tube with internal threads, which also serves as a threaded hole. The first threaded rod is threadedly connected to the first threaded hole; the second threaded rod is threadedly connected to the second threaded hole. The first connecting rings of the adjacent hydraulic pile cutting device units 1 are fixed by a pin, and the second connecting rings are fixed by a pin. The insertion lengths of the first threaded rod and the second threaded rod are adjustable, so that all the hydraulic pile cutting device units 1 can be spliced ​​and fixed according to preset sizes, thereby improving the installation accuracy of the equipment.

[0055] Embodiment 2

[0056] This embodiment provides a method for using the hydraulic pile cutting device unit as described in the first embodiment. Figures 1 to 9 The method of use is further described. The method of use comprises the following steps:

[0057] Step 1: In the initial state, the hydraulic expansion and contraction device is in a contracted state, and the first limit valve 61 and the second limit valve 62 limit the tooth groove 12 of the steel drill 10 in one direction;

[0058] Step 2: The hydraulic telescopic device 30 is extended, the force transmission device 40 pulls the movable seat 50 to move forward, the first limit valve 61 pushes the steel drill 10 to move forward synchronously by M tooth sockets 12, and the second limit valve 62 does not hinder the steel drill 10 from moving forward, where M is a preset value, M≥1;

[0059] Step 3: The hydraulic expansion and contraction device 30 is operated, the force transmission device 40 pushes the movable seat 50 to move backward, the first limit valve is synchronously moved backward by M tooth grooves 12, and the second limit valve 62 performs one-way limit on the tooth groove 12 of the steel drill 10, and the position of the steel drill 10 remains unchanged;

[0060] Step 4: Repeat steps 2 and 3 to gradually move the steel drill 10 forward.

[0061] In a specific embodiment, the first limit valve 61 and the second limit valve 62 perform one-way limiting on the tooth groove 12 of the steel drill 10 by clamping a fan-shaped limit plate in the tooth groove 12 for limiting. The tooth groove 12 has a forward slope and a backward vertical end face. The fan-shaped limit plate presses against the vertical end face to prevent the steel drill 10 from moving backward. When the steel drill 10 moves forward, the limit plate slides along the slope to the next tooth groove 12, thereby achieving one-way limiting of the steel drill 10.

[0062] In a specific embodiment, the specific structure of the force transmission device 40 refers to Example 1. When the hydraulic telescopic device 30 is extended, the power lever 41 rotates counterclockwise along the second hinge node, driving the straight connecting rod 43 to move the movable seat forward, and the first limit valve 61 pushes the steel drill 10 to move forward; when the hydraulic telescopic device 30 is contracted, the power lever 41 rotates clockwise along the second hinge node, driving the straight connecting rod 43 to move the movable seat backward, the first limit valve 61 moves backward, and the second limit valve 62 is still against the tooth socket of the steel drill 10 to keep the steel drill stationary.

[0063] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A hydraulic pile cutting device unit, It is characterized in that It includes a steel drill, a guide base, a movable seat, a hydraulic telescopic device, a force transmission device and a one-way moving device; The steel chisel is a cylinder with a pointed tip at one end, and a plurality of annular wedge-shaped tooth sockets are arranged on the cylinder; The guide base comprises a cylindrical body, a guide hole is arranged in the cylindrical body along the axial direction, a steel drill is arranged in the guide hole, a tip of the steel drill is located at the front end of the cylindrical body, and a tail of the steel drill extends out of the rear end of the cylindrical body; a hollow part is arranged on the cylindrical body; The movable seat is arranged at the tail of the guide base, a through hole is arranged in the middle and is sleeved on the tail of the steel drill; The one-way moving device includes a plurality of first limit valves and second limit valves, wherein the first limit valves are arranged on the movable base, and the second limit valves are arranged on the hollow part of the cylindrical body, and the first limit valves and the second limit valves are both connected with the steel drill tooth groove buckle to prevent the steel drill from moving backward; The hydraulic telescopic device is arranged on the cylindrical main body, and the force transmission device can transmit the displacement of the telescopic end of the hydraulic telescopic device to the movable seat. The telescopic movement of the hydraulic telescopic device can drive the movable seat to move forward and backward; when the movable seat moves forward, the first limit valve clamps the steel drill groove and pushes the steel drill forward. When the movable seat moves backward, the second limit valve clamps the steel drill groove and keeps the steel drill stationary.

2. The hydraulic pile cutting device unit according to claim 1, It is characterized in that A first hinge fulcrum is arranged at the top of the rear end of the cylindrical body, and a second hinge fulcrum is arranged at the bottom of the front end of the cylindrical body; The force transmission device includes two power levers, a power pin and two straight connecting rods; a power lever is arranged on each side of the cylindrical body, the bottom of the power lever is hinged to the second hinge fulcrum, and the tops of the two power levers are respectively hinged to the ends of the power pin; one end of the straight connecting rod is hinged to the middle of the power lever, and the other end is hinged to the movable seat; One end of the hydraulic telescopic device is hinged to the first hinge fulcrum, and the other end is hinged to the power pin shaft.

3. The hydraulic pile cutting device unit according to claim 1 or 2, It is characterized in that The first limit valve and the second limit valve both include a pin, a limit plate and a torsion spring. One end of the limit plate is sleeved on the pin, and the torsion spring is arranged on the pin. The pin of the first limit valve is arranged on the movable seat, and the pin of the second limit valve is arranged on the cylindrical body. The torsion spring causes the end of the limit plate to press the steel chisel and press against the annular wedge-shaped tooth groove.

4. The hydraulic pile cutting device unit according to claim 1 or 2, It is characterized in that The front end of the cylindrical body is provided with horizontal first threaded holes on both sides, and the rear end of the cylindrical body is provided with horizontal second threaded holes; The first threaded hole is provided with a first hinged head screw, and the second threaded hole is provided with a second hinged head screw; The first hinged joint screw rod comprises a first threaded rod and a first connecting ring arranged at one end of the first threaded rod; the first threaded rod is threadedly connected with the first threaded hole; The second hinged joint screw rod comprises a second threaded rod and a second connecting ear plate arranged at one end of the second threaded rod; the second threaded rod is threadedly connected with the second threaded hole.

5. A method for using the hydraulic pile cutting device unit according to any one of claims 1 to 4, It is characterized in that The steps include: Step 1: In the initial state, the hydraulic expansion and contraction device is in a contracted state, and the first limit valve and the second limit valve limit the steel drill tooth groove in one direction; Step 2: The hydraulic telescopic device is extended, the force transmission device pulls the movable seat forward, and the steel drill moves forward synchronously with the first limit valve by M tooth socket spacings, and the second limit valve does not hinder the steel drill from moving forward, where M is a preset value, M≥1; Step 3: The hydraulic expansion and contraction device is operated, the force transmission device pulls the movable seat to move backward, the first limit valve is synchronously moved backward by M tooth socket spacings, the second limit valve performs one-way limit on the steel drill tooth socket, and the position of the steel drill remains unchanged; Step 4: Repeat steps 2 and 3 to gradually move the steel drill forward.

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