A hydraulic device for tool quick change and engineering operation common use and telescopic arm forklift truck

Abstract

This invention relates to the field of telescopic boom forklift technology, and discloses a hydraulic device and telescopic boom forklift that can be used for both quick attachment change and engineering operations. The device includes a quick-change assembly, comprising a hydraulic telescopic member mounted on the tilting frame. The hydraulic telescopic member extends and retracts relative to the fork carriage to form a detachable connection structure. A hydraulic circuit includes a two-position six-way solenoid valve connected to both the hydraulic telescopic member and the attachment mounted on the fork carriage, selectively directing hydraulic oil to either the hydraulic telescopic member or the attachment. This invention achieves quick fork carriage change by installing a hydraulically driven telescopic member between the tilting frame and the fork carriage to form a detachable connection structure. Furthermore, the two-position six-way solenoid valve simultaneously connects the hydraulic telescopic member and the attachment, forming a hydraulic circuit with switchable hydraulic oil delivery paths, allowing the hydraulic oil to drive the extension and retraction of the hydraulic telescopic member or the operation of the attachment.

Description

Technical Field

[0001] This invention relates to the field of telescopic boom forklift technology, specifically to a hydraulic device and telescopic boom forklift that can be used for quick attachment changes and engineering operations. Background Technology

[0002] Forklifts, telescopic forklifts, and other construction machinery are widely used in construction, agriculture, warehousing, and other fields due to their multi-purpose nature. To enable quick switching between different tasks (such as loading, shoveling, and clamping), quick-change devices are usually configured between the main unit and attachments. The attachments are mounted on the fork carriage, and the tilting frame is mounted on the main unit. The fork carriage can be quickly separated from or fixed to the tilting frame through the quick-change device, which can improve the operational flexibility and economy of the equipment.

[0003] Currently, existing quick-change attachment devices are mainly divided into two categories: hydraulically driven and electrically driven. For example, Chinese patent CN203781767U discloses a quick-change bracket for forklift attachments. This bracket adopts a frame structure with a fixed sleeve at the rear that hinges to the forklift boom and tie rod. A double-acting hydraulic cylinder is horizontally mounted at the lower part of the frame, with a quick-change pin connected to a single-rod piston at each end of the cylinder. A hook pin is located at the top of the frame. In use, the hook pin engages with the hook on the upper back of the attachment, and the double-acting hydraulic cylinder drives the quick-change pin to retract, locking or releasing the lug on the lower back of the attachment. This solution achieves cab-operated control via hydraulic drive, resulting in high attachment changing efficiency. However, its drawback is that the quick-change device's own double-acting cylinder requires an independent hydraulic interface provided by the main unit. Most construction machinery has a limited number of hydraulic interfaces reserved for attachments. When installing attachments that require hydraulic drive, the operator must disconnect the hydraulic line of the quick-change device and then reconnect the hydraulic line of the attachment. The process is cumbersome and time-consuming. Furthermore, repeated plugging and unplugging can easily lead to contamination of hydraulic joints and wear of seals, affecting the reliability of the system.

[0004] To avoid the aforementioned hydraulic interface conflict issues, another solution employs an electric drive. For example, Chinese patent CN117800263B discloses a telescopic boom forklift and its attachment assembly / disassembly method. Its quick-change device includes a mounting base with a hanging shaft at the front end. The locking component uses a stepper motor to drive a lead screw, causing locking pins at both ends of the lead screw to reciprocate within a guide sleeve, thereby locking and unlocking the attachment. This solution does not occupy any hydraulic interface, and the driver can operate it electronically from the cab. However, this electric drive solution has the following inherent limitations: First, it adds an extra electric drive structure; second, the motor, control circuitry, and worm gear components have a relatively high failure rate under harsh working conditions such as dust, humidity, and severe vibration, making maintenance and replacement inconvenient; furthermore, the manufacturing cost of the electric drive system is significantly higher than that of hydraulic components, which is detrimental to overall machine cost control.

[0005] In summary, while existing hydraulic quick-change devices are simple in structure and low in cost, their exclusive use of the hydraulic interface leads to poor compatibility with hydraulic attachments. Existing electric quick-change devices, although free from occupying the hydraulic interface, have significant shortcomings in terms of environmental applicability and cost. How to retain the high thrust and high reliability of hydraulic drive while avoiding the encroachment on the attachment's hydraulic interface, and achieve flexible sharing of hydraulic power between quick locking and attachment operation, has become a technical challenge in this field. Summary of the Invention

[0006] To address the challenge of retaining hydraulic drive while avoiding encroachment on the hydraulic interfaces of attachments, and to achieve flexible sharing of hydraulic power between quick locking and attachment operation, this invention provides a hydraulic device and telescopic boom forklift that can be used for both quick attachment changes and engineering operations. The specific technical solution is as follows: A hydraulic device for quick attachment changing and engineering operations is disclosed. A tilting frame and a fork carriage form a detachable connection structure driven by the hydraulic device. The hydraulic device includes: a quick-change assembly, which includes a hydraulic telescopic member disposed on the tilting frame. The hydraulic telescopic member extends and retracts relative to the fork carriage to form a detachable connection structure; and a hydraulic circuit, which includes a two-position six-way solenoid valve connected to the hydraulic telescopic member and the attachment disposed on the fork carriage to drive hydraulic oil to selectively flow to the hydraulic telescopic member or the attachment.

[0007] Furthermore, the two-position six-way solenoid valve forms interfaces A, B, C, and D, with interfaces A and B forming the first group and interfaces C and D forming the second group. When the two six-way solenoid valves are not energized, the first group is connected to the oil pump, and the hydraulic telescopic component is connected to the oil pump to form a detachable connection structure. When the two six-way solenoid valves are energized, the second group is connected to the oil pump, and the attachment is connected to the oil pump.

[0008] Preferably, the hydraulic circuit further includes a flow control valve disposed between the two-position six-way solenoid valve and the oil pump. The two-position six-way solenoid valve also includes interface E and interface F, which are respectively connected to the oil inlet and oil outlet of the flow control valve to form a hydraulic circuit in which hydraulic oil flows sequentially through the oil pump, the flow control valve, the two-position six-way solenoid valve, the hydraulic telescopic component or attachment.

[0009] Preferably, the hydraulic telescopic component includes: The cylinder body installed in the tilting frame has a through cavity inside, which forms a middle area and two end areas; Single-rod pistons are respectively set in the two end regions. The rodless end of the single-rod piston is arranged opposite to each other and fits into the through cavity to form an intermediate cavity for accommodating hydraulic oil for extension. The rod end of the single-rod piston cooperates with the guide sleeves set in the two end regions to form two end cavities to accommodate hydraulic oil for retraction.

[0010] Preferably, the rod body is formed at the rod end of the single-rod piston, and the rod body is slidably connected to the guide sleeve to form cavities at both ends; The rodless end forms a sealed structure to separate the middle cavity and the two end cavities; When hydraulic oil is injected into the intermediate cavity through interface G, the single-rod piston moves in opposite directions to connect the rod body with the fork carriage. When hydraulic oil is injected into the cavities at both ends through the ports H on both sides, the single-rod pistons move towards each other to separate the rod from the fork carriage.

[0011] Preferably, the quick-change component further includes: A fixed shaft is symmetrically arranged at the upper end of the tilting frame, and hooks are symmetrically formed at the upper end of the fork carriage. The hooks are attached to the fixed shaft to form the rotation fulcrum of the tilting frame and the fork carriage.

[0012] Preferably, the quick-change component further includes: Symmetrical positioning holes formed at the lower end of the fork carriage; and The positioning blocks symmetrically arranged at the lower end of the fork carriage allow the positioning holes to correspond with the hydraulic telescopic components when the fork carriage and tilting frame rotate towards each other until the positioning blocks restrict the rotation of the fork carriage and tilting frame towards each other, thus forming a detachable connection structure.

[0013] A telescopic boom forklift includes: a hydraulic system; and an oil pump connected to the hydraulic system.

[0014] As can be seen from the above technical solution, the present invention has the following beneficial effects: This invention uses a hydraulically driven telescopic component installed between the tilting frame and the fork carriage to form a detachable connection structure, thereby enabling quick replacement of the fork carriage. Secondly, a two-position six-way solenoid valve simultaneously connects the hydraulic telescopic component and the attachment, forming a hydraulic oil circuit with switchable hydraulic oil delivery paths, thereby enabling the hydraulic oil to drive the extension and retraction of the hydraulic telescopic component or drive the attachment to operate. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of Embodiment 1 installed in Embodiment 2 of the present invention; Figure 2 for Figure 1 N partial views in the image; Figure 3 This is a schematic diagram of the hydraulic circuit of a hydraulic device. Figure 4 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 5 for Figure 4 A partial view at point M in the image; Figure 6 This is a sectional view of the hydraulic telescopic component; Figure 7 This is a structural diagram of the fork carriage.

[0016] In the diagram: 1. Tilting frame; 2. Fork carriage; 3. Quick-change assembly; 31. Fixed shaft; 32. Hydraulic telescopic component; 321. Cylinder body; 322. Central cavity; 323. End cavities; 324. Single-rod piston; 33. Hook; 34. Positioning hole; 35. Positioning block; 4. Hydraulic circuit; 41. Two-position six-way solenoid valve; 42. Flow control valve; 43. Interface A; 44. Interface B; 45. Interface C; 46. Interface D; 47. Interface E; 48. Interface F; 49. Interface G; 50. Interface H; 6. Oil pump. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] In the description of the embodiments of the present invention, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0019] Example 1 like Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, Figure 1 The embodiment 1 is installed at the end of the telescopic boom of a forklift. This embodiment 1 is a hydraulic device for quick attachment change and engineering operation. The tilting frame 1 and the fork carriage 2 form a detachable connection structure driven by the hydraulic device. The hydraulic device includes: a quick-change component 3, which includes a hydraulic telescopic component 32 disposed on the tilting frame 1. The hydraulic telescopic component 32 extends and retracts relative to the fork carriage 2 to form a detachable connection structure; and a hydraulic oil circuit 4, which includes a two-position six-way solenoid valve 41 connected to the hydraulic telescopic component 32 and the attachment disposed on the fork carriage 2 to drive hydraulic oil to selectively flow to the hydraulic telescopic component 32 or the attachment.

[0020] Specifically, the tilting frame 1 is fixedly installed at the end of the telescopic boom of the forklift. Driving the tilting frame 1 to tilt and move either the tilting frame 1 or the fork carriage 2 on the ground, the fork carriage 2 and the tilting frame 1 form a detachable connection structure, allowing the operator to change the fork carriage 2 according to the work being performed. The hydraulic telescopic component 32 is fixedly installed to the tilting frame 1 by bolts or welding. It achieves its telescopic function through hydraulic oil, thus forming a detachable connection structure with the through holes of the fork carriage 2. The hydraulic telescopic component 32 can be installed at both the upper and lower ends of the tilting frame 1, and then inserted into the through holes at both ends of the fork carriage 2 to form a fixed connection. Alternatively, it can be installed only at the lower end of the tilting frame 1, with the upper end connected by other fixed structures (such as hooks 33 hanging on the fixed shaft 31, facilitating disassembly and preventing the fork carriage 2 from detaching from the tilting frame 1 during operation). This achieves a hydraulically driven quick-release structure, simplifying the structure and reducing costs.

[0021] Secondly, one end of the two-position six-way solenoid valve 41 is connected to the oil pump 6, and the other end is connected to the hydraulic telescopic component 32 or the attachment. The interior of the two-position six-way solenoid valve 41 forms a switchable hydraulic circuit 4. When the hydraulic circuit 4 is connected to the hydraulic telescopic component 32, the hydraulic telescopic component 32 can extend and retract to realize the quick connection or separation of the tilting frame 1 and the fork carriage 2. When the hydraulic circuit 4 is connected to the attachment, the attachment can start working (such as clamping), thereby realizing the flexible sharing of the same set of hydraulic power between quick locking and attachment operation, thereby simplifying the structure and reducing costs.

[0022] like Figure 1 , Figure 2 and Figure 3 As shown, the two-position six-way solenoid valve 41 forms interfaces A43, B44, C45, and D46. Interfaces A43 and B44 form the first group, and interfaces C45 and D46 form the second group. When the two-position six-way solenoid valve 41 is not energized, the first group is connected to the oil pump 6, and the hydraulic telescopic component 32 is connected to the oil pump 6 to form a detachable connection structure. When the two-position six-way solenoid valve 41 is energized, the second group is connected to the oil pump 6, and the attachment is connected to the oil pump 6. The hydraulic circuit 4 also includes a flow control valve 42 disposed between the two-position six-way solenoid valve 41 and the oil pump 6. The two-position six-way solenoid valve 41 also includes interfaces E47 and F48, which are respectively connected to the inlet and outlet of the flow control valve 42 to form a hydraulic circuit in which hydraulic oil flows sequentially through the oil pump 6, the flow control valve 42, the two-position six-way solenoid valve 41, the hydraulic telescopic component 32, or the attachment.

[0023] Specifically, the oil pump 6 forms two oil ports, which are connected to the inlet and outlet of the flow control valve 42, respectively. The inlet and outlet of the flow control valve 42 are connected to interface E47 and interface F48, respectively. The flow control valve 42 is a three-position four-way directional valve, which can switch the position of the internal valve core to change the flow of hydraulic oil from interface E47 or interface F48 to interface F48 or interface E47, forming a hydraulic circuit for quick-change of attachments. Secondly, when the two-position six-way solenoid valve 41 is not energized, interface E47 is connected to interface C45. Interface F48 is connected to interface D46, interface C45 is connected to interface G49, and interface D46 is connected to interface H50. When the flow control valve 42 injects hydraulic oil into interface E47 through the oil outlet, the hydraulic oil flows through interface C45 and interface G49 in sequence, causing the rod of the single-rod piston 324 to extend and insert into the positioning hole 34 of the fork carriage 2. The hydraulic oil in the cavities 323 at both ends is squeezed out from interface H50 and flows through interface D46, interface F48, and the oil inlet of the flow control valve 42 in sequence, finally entering the oil pump 6. Next, when the two-position six-way solenoid valve 41 is energized, section a pushes the valve core to move to the right, and section b compresses the spring. Interface E47 is connected to interface A43, and interface F48 is connected to interface B44. Interfaces A43 and B44 are respectively connected to the oil circuit interface of the attachment, forming the hydraulic oil circuit 4 for attachment operation, enabling the attachment to perform operations.

[0024] like Figure 6 As shown, the hydraulic telescopic component 32 includes: a cylinder 321 disposed on the tilting frame 1, the interior of the cylinder 321 forming a through cavity, the through cavity forming a middle region and two end regions; a single-rod piston 324 disposed in each of the two end regions, the rodless end of the single-rod piston 324 being disposed opposite to and fitted with the through cavity to form a middle cavity 322 for accommodating hydraulic oil for extension, the rod end of the single-rod piston 324 cooperating with guide sleeves disposed in the two end regions to form two end cavities 323 for accommodating hydraulic oil for retraction; a rod formed on the rod end of the single-rod piston 324, the rod being slidably connected to the guide sleeve to form two end cavities 323; and a sealing structure formed at the rodless end to separate the middle cavity 322 and the two end cavities 323.

[0025] Specifically, the cylinder body 321 is fixedly installed at the lower end of the tilting frame 1 by bolts or welding. Its length direction is parallel to the length direction of the tilting frame 1 and the fork carriage 2. The cylinder body 321 is formed by machining of a hollow pipe inside, with a central cavity 322 in the middle area, allowing hydraulic oil to enter through the two-position six-way solenoid valve 41, thereby pushing the single-rod pistons 324 at both ends to move in opposite directions, realizing the extension function of the hydraulic telescopic component 32, which is then inserted into the through holes on both sides of the lower end of the fork carriage 2 for fixation. Secondly, single-rod pistons 324 are respectively placed at both ends of the cylinder body 321, including a rod end and a rodless end. The rod end and the rodless end can be integrated or assembled separately. The rod end forms a positioning shaft that extends out and inserts into the through hole of the fork carriage 2, and the rodless end forms a piston that slides along the inner wall of the area at both ends. The circumference of the piston is fitted with Equipped with sealing rings, the rodless ends are all close to the central cavity 322, while the rod-ends form two-end cavities 323, thus preventing hydraulic oil from the central cavity 322 from flowing into the two-end cavities 323. Guide sleeves (such as linear bearings) are installed at the leftmost and rightmost ends inside the cylinder body 321. The rod of the rod-end forms a sliding connection with the guide sleeve, thus forming one of the two-end cavities 323. When hydraulic oil enters the two-end cavities 323, the volume of the two-end cavities 323 increases, pushing the rodless ends to move towards each other. The rod of the rod-end retracts, and the hydraulic telescopic component 32 separates from the through hole of the fork carriage 2. When hydraulic oil enters the central cavity 322, the volume of the central cavity 322 increases, pushing the rodless ends to move away from each other. The rod of the rod-end extends, and the rod of the hydraulic telescopic component 32 inserts into the through hole of the fork carriage 2, allowing the operator to quickly change the fork carriage 2.

[0026] Furthermore, when hydraulic oil is injected into the intermediate cavity 322 through interface G49, the single-rod piston 324 moves in opposite directions to connect the rod body with the fork carriage 2; when hydraulic oil is injected into the two-end cavities 323 through interfaces H50 on both sides, the single-rod piston 324 moves towards each other to separate the rod body from the fork carriage 2.

[0027] Specifically, the side wall of the cylinder body 321 in the middle region forms a through interface G49, which allows hydraulic oil to enter the middle cavity 322 through the distribution of the two-position six-way solenoid valve 41, and the hydraulic oil in the two end cavities 323 flows out through the interface H50, forming a hydraulic circuit; the side wall of the cylinder body 321 in the two end regions forms a through interface H50, which allows hydraulic oil to enter the two end cavities 323 through the distribution of the two-position six-way solenoid valve 41, and the hydraulic oil in the middle cavity 322 flows out through the interface G49, forming a hydraulic circuit.

[0028] like Figure 7 As shown, the quick-change assembly 3 also includes: a fixed shaft 31 symmetrically arranged at the upper end of the tilting frame 1 and hooks 33 symmetrically formed at the upper end of the fork carriage 2. The hooks 33 are attached to the fixed shaft 31 to form the rotation fulcrum of the tilting frame 1 and the fork carriage 2.

[0029] Specifically, the symmetrical planes of the tilting frame 1 and the fork carriage 2 are both the central planes perpendicular to the length direction. Fixed shafts 31 are welded to both sides of the upper end of the tilting frame 1, and the diameter of the fixed shafts 31 is no greater than the inner diameter of the hooks 33. Hooks 33 are cut to form both ends of the upper end of the fork carriage 2, with open ends to allow the fixed shafts 31 to be inserted and fixed, thus enabling the fork carriage 2 to rotate relative to the tilting frame 1. The fixed shafts 31 and hooks 33 are symmetrically arranged, and limiting plates are welded to both sides of the fixed shafts 31. The limiting plates are positioned between the hooks 33 on both sides, restricting the movement of the hooks 33 along the axis of the fixed shafts 31, thus giving the hooks 33 only one degree of freedom, namely, detaching from the fixed shafts 31 along the open end direction.

[0030] Furthermore, the quick-change assembly 3 also includes: positioning holes 34 symmetrically formed at the lower end of the fork carriage 2; and positioning blocks 35 symmetrically arranged at the lower end of the fork carriage 2. When the fork carriage 2 and the tilting frame 1 rotate toward each other until the positioning blocks 35 restrict the fork carriage 2 and the tilting frame 1 from rotating toward each other, the positioning holes 34 can correspond to the hydraulic telescopic member 32 to form a detachable connection structure.

[0031] Specifically, vertical plates are symmetrically welded on both sides of the fork carriage 2. The lower end of the vertical plates forms a positioning hole 34, and a positioning block 35 is welded on the opposite side of the vertical plates. When the hook 33 of the fork carriage 2 is fixed to the fixed shaft 31 of the tilting frame 1, and the telescopic arm rotates the tilting frame 1, the lower end of the fork carriage 2 approaches the lower end of the tilting frame 1 until the positioning block 35 contacts the tilting frame 1. At this time, the positioning hole 34 is coaxial with the rod of the hydraulic telescopic component 32, and hydraulic oil flows into the intermediate cavity 322, driving the single rod piston 324 to move in opposite directions, so that the rod is inserted into the positioning hole 34, thereby fixing the fork carriage 2 and the tilting frame 1 relatively, realizing the quick replacement of the fork carriage 2.

[0032] Example 2 This second embodiment is a telescopic boom forklift, which includes: (as in Embodiment 1); an oil pump 6 connected to a hydraulic system. Specifically, the hydraulic system connects the tilting frame 1 and the fork carriage 2. The tilting frame 1 is connected to the end of the telescopic boom of the forklift. The specific replacement procedure for the fork carriage 2 is as follows: The fork carriage 2 is placed on the ground. The operator controls the flow valve to supply hydraulic oil to the two end cavities 323. The single-rod piston 324 retracts, and the tipping frame 1 separates from the lower end of the fork carriage 2. The forklift tilts the tipping frame 1, causing the fixed shaft 31 of the tipping frame 1 to separate from the hook 33 of the fork carriage 2, achieving rapid separation between the two. Next, during installation, the fork carriage 2 that needs to be replaced is placed on the ground. The forklift tilts the tipping frame 1 in the opposite direction and drives it close to the fork carriage 2 until the fork carriage 2... The hook 33 is connected to the fixed shaft 31 of the tilting frame 1. The forklift lifts the tilting frame 1 and the fork carriage 2 and tilts the tilting frame 1, so that the fork carriage 2 moves closer to the tilting frame 1 around the fixed shaft 31 until the positioning block 35 contacts the tilting frame 1. The operator operates the flow control valve 42 to deliver hydraulic oil to the intermediate cavity 322. The single rod piston 324 extends and inserts into the positioning hole 34 to realize the fixed connection between the fork carriage 2 and the tilting frame 1, thereby realizing the quick replacement of the fork carriage 2 and the tilting frame 1.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0034] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A hydraulic device for quick attachment changing and engineering operations, wherein a tilting frame (1) and a fork carriage (2) form a detachable connection structure driven by the hydraulic device, characterized in that, The hydraulic device includes: Quick-change assembly (3), the quick-change assembly (3) includes a hydraulic telescopic member (32) disposed on the tilting frame (1), the hydraulic telescopic member (32) extending and retracting relative to the fork carriage (2) to form the detachable connection structure; The hydraulic circuit (4) includes a two-position six-way solenoid valve (41) connected to the hydraulic telescopic member (32) and the attachment disposed on the fork carriage (2) to drive hydraulic oil to selectively flow to the hydraulic telescopic member (32) or the attachment.

2. The hydraulic device according to claim 1, characterized in that: The two-position six-way solenoid valve (41) forms an interface A (43), an interface B (44), an interface C (45), and an interface D (46). The interface A (43) and the interface B (44) are the first group, and the interface C (45) and the interface D (46) are the second group. When the two-position six-way solenoid valve (41) is not energized, the first group is connected to the oil pump (6), and the hydraulic telescopic component (32) is connected to the oil pump (6) to form the detachable connection structure. When the two-position six-way solenoid valve (41) is energized, the second group is connected to the oil pump (6), and the attachment is connected to the oil pump (6).

3. The hydraulic device according to claim 2, characterized in that: The hydraulic circuit (4) further includes a flow control valve (42) disposed between the two-position six-way solenoid valve (41) and the oil pump (6). The two-position six-way solenoid valve (41) further includes an interface E (47) and an interface F (48). The interface E (47) and the interface F (48) are respectively connected to the oil inlet and oil outlet of the flow control valve (42) to form a hydraulic circuit in which hydraulic oil flows sequentially through the oil pump (6), the flow control valve (42), the two-position six-way solenoid valve (41), the hydraulic telescopic component (32), or the attachment.

4. The hydraulic device according to claim 1, characterized in that: The hydraulic telescopic component (32) includes: The cylinder (321) disposed in the tilting frame (1) has a through cavity inside, which forms a middle area and two end areas; Single-rod pistons (324) are respectively disposed in the two end regions. The rodless end of the single-rod piston (324) is disposed opposite to each other and fits against the through cavity to form an intermediate cavity (322) for accommodating hydraulic oil for extension. The rod end of the single-rod piston (324) cooperates with the guide sleeve disposed in the two end regions to form two end cavities (323) for accommodating hydraulic oil for retraction.

5. The hydraulic device according to claim 4, characterized in that: A rod is formed at the rod end of the single-rod piston (324), and the rod is slidably connected to the guide sleeve to form the two-end cavities (323); The rodless end forms a sealing structure to separate the intermediate cavity (322) and the two end cavities (323); When hydraulic oil is injected into the intermediate cavity (322) through interface G (49), the single rod piston (324) moves in opposite directions to connect the rod body with the fork carriage (2); When hydraulic oil is injected into the two-end cavities (323) through the interfaces H (50) on both sides, the single-rod piston (324) moves towards each other to separate the rod from the fork carriage (2).

6. The hydraulic device according to claim 1, characterized in that: The quick-change component (3) also includes: A fixed shaft (31) is symmetrically arranged at the upper end of the tilting frame (1) and a hook (33) is symmetrically formed at the upper end of the fork carriage (2). The hook (33) is attached to the fixed shaft (31) to form the rotation fulcrum of the tilting frame (1) and the fork carriage (2).

7. The hydraulic device according to claim 1, characterized in that: The quick-change component (3) also includes: Positioning holes (34) symmetrically formed at the lower end of the fork carriage (2); and The positioning block (35) is symmetrically arranged at the lower end of the fork carriage (2). When the fork carriage (2) and the tilting frame (1) rotate towards each other, until the positioning block (35) restricts the fork carriage (2) and the tilting frame (1) from rotating towards each other, the positioning hole (34) can correspond to the hydraulic telescopic member (32) to form the detachable connection structure.

8. A telescopic boom forklift, characterized in that, include: The hydraulic device as described in any one of claims 1 to 7; and an oil pump (6) connected to the hydraulic device.

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