Differential bidirectional parallel four-bar linkage synchronous combination hydraulic cylinder

Abstract

The application discloses a differential type bidirectional parallel four-out-rod synchronous combined hydraulic cylinder, which comprises a first double-out-rod combined hydraulic cylinder and a second double-out-rod combined hydraulic cylinder which are combined into one body in the axial direction and share the same cylinder bottom; and the first double-out-rod combined hydraulic cylinder and the second double-out-rod combined hydraulic cylinder are combined in parallel in the radial direction to form a four-out-rod hydraulic cylinder. The application effectively reduces the number of independent hydraulic cylinders, eliminates the support structure of independent installation of multiple cylinders, and significantly reduces the overall volume. The integrated oil circuit system will significantly reduce the number of external pipelines and avoid the leakage risk caused by the intersection of multiple pipelines. The symmetrical layout of the four piston rods enhances the structural stability, effectively improves the synchronous action precision, and is suitable for space-limited scenes such as a steering system. The overall structure realizes function expansion through modular combination, reduces the manufacturing cost while guaranteeing the synchronous performance.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder technology, and in particular to a differential bidirectional parallel four-rod synchronous combination hydraulic cylinder. Background Technology

[0002] With the rapid development of special equipment machinery, higher functional requirements have been placed on hydraulic actuators. In applications such as steering systems for special vehicles, traditional hydraulic cylinders exhibit significant functional limitations. Current technologies typically employ multiple independent hydraulic cylinders connected in parallel to achieve multi-directional synchronous action. This approach not only requires complex piping systems but also occupies a large amount of installation space. Especially in space-constrained equipment environments, the arrangement of multiple hydraulic cylinders often affects the overall structural layout of the machine.

[0003] The main technical challenges currently facing hydraulic cylinder technology include: difficulty in achieving precise synchronous control in multi-cylinder parallel systems; increased risk of system leakage due to complex piping layouts; the need for additional support structures for the installation of multiple independent hydraulic cylinders; and high system energy consumption and maintenance difficulties. These problems are particularly pronounced in operating conditions requiring bidirectional synchronous extension and positioning locking, such as in vehicle steering systems, where the synchronization accuracy of left and right steering actions directly affects the overall vehicle handling performance.

[0004] While existing hydraulic cylinder products can achieve basic telescopic functions, they have significant shortcomings in differential bidirectional synchronous control. When synchronous telescopic extension and retraction of four piston rods is required, traditional solutions must configure four independent hydraulic cylinders, which not only increases system complexity but also leads to a decrease in control accuracy. Furthermore, connecting multiple hydraulic cylinders requires numerous joints and pipelines, significantly increasing the risk of system failure. Summary of the Invention

[0005] In view of this, the present invention provides a differential bidirectional parallel four-outlet synchronous combined hydraulic cylinder, which has the advantages of compact structure, high synchronization accuracy, high installation space utilization and significant reduction in system leakage risk.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A differential bidirectional parallel four-rod synchronous combined hydraulic cylinder includes: a first double-rod combined hydraulic cylinder and a second double-rod combined hydraulic cylinder, which are composed of two single-rod combined hydraulic cylinders sharing the same cylinder bottom and axially combined into one unit; the first double-rod combined hydraulic cylinder and the second double-rod combined hydraulic cylinder are radially connected in parallel to form a four-rod hydraulic cylinder.

[0007] Preferably, both the first and second double-rod combined hydraulic cylinders have an integral cylinder bottom in the middle. The integral cylinder bottom of the first double-rod combined hydraulic cylinder has a plug groove, and the integral cylinder bottom of the second double-rod combined hydraulic cylinder has a plug. The first and second double-rod combined hydraulic cylinders are connected in parallel through the engagement of the plug groove and the plug.

[0008] Preferably, the insertion slot is a cross-shaped square slot.

[0009] Preferably, the integrated cylinder bottom is a square-round integrated cylinder bottom.

[0010] Preferably, the differential bidirectional parallel four-outlet synchronous combination hydraulic cylinder further includes a connecting plate, which is disposed on the side of the four-outlet hydraulic cylinder and fixedly connected to the first double-outlet combination hydraulic cylinder and the second double-outlet combination hydraulic cylinder respectively.

[0011] Preferably, the differential bidirectional parallel four-rod synchronous combination hydraulic cylinder further includes a connector assembly, which includes a first connector seat, a first connector pipe, a second connector seat, and a second connector pipe. The first connector seat and the second connector seat are spaced apart and installed on the first double-rod combination hydraulic cylinder. Both the first connector seat and the second connector seat are provided with connector oil ports. The first connector seat is connected to two oil inlet chambers in the first double-rod combination hydraulic cylinder and two oil return chambers in the second double-rod combination hydraulic cylinder through the first connector pipe. The second connector seat is connected to two oil return chambers in the first double-rod combination hydraulic cylinder and two oil inlet chambers in the second double-rod combination hydraulic cylinder through the second connector pipe.

[0012] Preferably, spherical bearings are installed on the lugs at both ends of the first double-rod combined hydraulic cylinder and the second double-rod combined hydraulic cylinder.

[0013] Preferably, both the first and second double-rod combined hydraulic cylinders are equipped with sensor connectors, and proximity switches are installed on the sensor connectors.

[0014] The beneficial effects of this invention are as follows: Compared with the prior art, this application effectively reduces the number of independent hydraulic cylinders, eliminates the bracket structure for independent installation of multiple cylinders, and significantly reduces the overall volume. The integrated oil circuit system will significantly reduce the number of external pipelines and avoid the leakage risk caused by multiple pipeline intersections. The symmetrical layout of the four piston rods enhances structural stability, effectively improves the accuracy of synchronous action, and is suitable for space-constrained scenarios such as steering systems. The overall structure achieves functional expansion through modular combination, reducing manufacturing costs while ensuring synchronous performance.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the differential bidirectional parallel four-outlet synchronous combined hydraulic cylinder of the present invention; Figure 2 This is a front view of the differential bidirectional parallel four-outlet synchronous combined hydraulic cylinder of the present invention; Figure 3 This is a side view of the differential bidirectional parallel four-outlet synchronous combined hydraulic cylinder of the present invention.

[0017] Figure label: 1. Earring; 2. Cylinder; 3. First connector seat; 4. First connector pipeline; 5. Second connector seat; 6. Second connector pipeline; 7. Integrated cylinder bottom; 8. Cross-shaped square groove; 9. Connecting plate; 10. Sensor connector seat. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] The following is for reference. Figures 1 to 3 This invention describes a differential bidirectional parallel four-outlet synchronous combined hydraulic cylinder in an embodiment of the present invention.

[0021] This application discloses a differential bidirectional parallel four-rod synchronous combined hydraulic cylinder, comprising: a first double-rod combined hydraulic cylinder and a second double-rod combined hydraulic cylinder, which are composed of two single-rod combined hydraulic cylinders sharing the same cylinder bottom and axially combined into one unit; the first double-rod combined hydraulic cylinder and the second double-rod combined hydraulic cylinder are radially connected in parallel to form a four-rod hydraulic cylinder.

[0022] Sharing the same cylinder bottom refers to the two single-rod hydraulic cylinders forming an integral structure at their axial ends by sharing a cylinder bottom. Specifically, the ends of the two cylinders can be connected by casting or welding, reducing the number of components by eliminating independent cylinder bottoms. Radial parallel combination refers to two double-rod hydraulic cylinders arranged and connected along the vertical axis. Specifically, they can be fixed using a plug-in structure or connecting plate 9, achieving a symmetrical distribution of the four piston rods through a spatial orthogonal layout.

[0023] Specifically, two single-rod hydraulic cylinders share a cylinder bottom to form a dual-rod unit with bidirectional output capability. This fusion structure allows the two cylinders to share a hydraulic chamber, reducing redundant sealing structures found in traditional multi-cylinder assembly. The two dual-rod units are radially paralleled to form a four-rod structure, with the four piston rods symmetrically arranged in orthogonal directions in space. When hydraulic oil is input through the integrated oil circuit, the two dual-rod units form a differential oil circuit system, causing the four piston rods to move synchronously in opposite directions. The shared cylinder bottom design provides the structural basis for oil circuit integration, allowing the inlet and return oil chambers to connect within the combined unit, eliminating the need for complex external piping.

[0024] Compared to existing technologies, traditional solutions require four independent hydraulic cylinders to achieve the movement of four piston rods, while this solution reduces the number of hydraulic cylinders to two combined units through structural assembly. Existing technologies require separate mounting brackets for independent installation of multiple cylinders, while this solution achieves an integrated structure through radial parallel connection, reducing installation complexity. Traditional multi-cylinder systems require more than four sets of pipeline connections, while this solution utilizes a shared cylinder base to achieve integrated hydraulic circuits, requiring only two main hydraulic circuits to control the synchronous movement of the four piston rods.

[0025] Through the above technical solutions, this application effectively reduces the number of independent hydraulic cylinders, eliminates the bracket structure for independent multi-cylinder installation, and significantly reduces the overall size. The integrated hydraulic circuit system will significantly reduce the number of external pipelines and avoid the leakage risk caused by multiple pipeline intersections. The symmetrical layout of the four piston rods enhances structural stability and effectively improves the accuracy of synchronous action, making it suitable for space-constrained scenarios such as steering systems. The overall structure achieves functional expansion through modular combination, reducing manufacturing costs while ensuring synchronous performance.

[0026] In some embodiments, for example Figure 1 As shown, both the first and second double-rod combined hydraulic cylinders have an integrated cylinder base 7 in the middle. The first double-rod combined hydraulic cylinder's integrated cylinder base 7 has a connector groove, while the second double-rod combined hydraulic cylinder's integrated cylinder base 7 has a plug. The first and second double-rod combined hydraulic cylinders are connected in parallel via the connector groove and plug. The connector groove is a cross-shaped square groove 8. The integrated cylinder base 7 is a square-round integrated cylinder base 7.

[0027] The integrated cylinder bottom 7 refers to a structure where two single-rod hydraulic cylinders share the same cylinder bottom and are axially integrated. By eliminating the connection interface of separate cylinder bottoms, the structural strength of the cylinder body can be improved and the risk of seal failure can be avoided. The insertion slot refers to a groove structure on the integrated cylinder bottom 7, which can be implemented using the geometry of a cross-shaped square groove 8. By limiting the movement freedom of the plug, mechanical limiting in the left-right and front-back directions can be achieved. The plug refers to a protruding structure that matches the insertion slot, which can be implemented using a cross-shaped protrusion structure complementary to the insertion slot. By embedding into the insertion slot to form an interlocking fit, the radial positioning accuracy of the two double-rod hydraulic cylinders can be ensured.

[0028] Specifically, when two dual-rod hydraulic cylinders need to be connected in parallel, the plug is embedded in the insertion slot, and automatic alignment is achieved by matching their geometric shapes. The cross-shaped square groove 8 of the insertion slot can limit the lateral displacement of the plug in the horizontal plane, while the tight fit between the plug and the insertion slot can eliminate relative misalignment during radial movement. The integrated cylinder bottom 7 provides rigid support for the insertion structure, avoiding deformation caused by local stress concentration. Through the mechanical interlock between the insertion slot and the plug, the two hydraulic cylinders can be fixed without the need for bolts or welding, and the self-alignment characteristic during the insertion process simplifies the assembly steps.

[0029] Through the above technical solution, this application solves the problems of complex structure, insufficient connection stability, and low assembly efficiency when two double-rod hydraulic cylinders are connected in parallel. The plug-in structure replaces the traditional connection method, allowing for accurate positioning of the hydraulic cylinders during parallel assembly without complex tooling. The integrated cylinder bottom 7 and the plug-in groove design enhance the overall structural rigidity, ensuring the relative positional stability of the two cylinders under high-pressure conditions. The limiting function of the cross-shaped square groove 8 prevents misalignment of the hydraulic cylinders under radial force, thereby improving the reliability of synchronous action.

[0030] In some embodiments, for example Figure 1 and Figure 2 As shown, the differential bidirectional parallel four-out rod synchronous combination hydraulic cylinder also includes a connecting plate 9, which is disposed on the side of the four-out rod hydraulic cylinder and is fixedly connected to the first double-out rod combination hydraulic cylinder and the second double-out rod combination hydraulic cylinder respectively.

[0031] The connecting plate 9 refers to a metal plate with a planar structure, which can be rigidly fixed to the side wall of the hydraulic cylinder by welding or bolting. This component forms a lateral constraint by covering the side contact surfaces of the two hydraulic cylinders, thereby counteracting the shear force generated by the radial parallel combination.

[0032] Specifically, after the insertion slots are positioned to limit movement in the left-right and front-back directions, the connecting plate 9 is installed on the outer side surface of the two double-rod combined hydraulic cylinders. By welding the edges of the connecting plate 9 to the side walls of the cylinder barrels 2 of the upper and lower hydraulic cylinders respectively, a continuous rigid connection interface is formed. This connection interface covers the lateral projection area of ​​the parallel hydraulic cylinder assembly, thus mechanically blocking the relative displacement of the upper and lower hydraulic cylinders in the vertical direction.

[0033] Through the above technical solution, this application effectively eliminates the risk of vertical misalignment that may occur when dual-rod hydraulic cylinders are radially parallel, while enhancing the torsional resistance of the assembly under dynamic working conditions through lateral rigid connection. The planar mounting method of the connecting plate 9 ensures that the hydraulic cylinder assembly forms mechanical constraints in all six degrees of freedom, without increasing the radial mounting space requirement of the hydraulic cylinders, thus meeting the requirements of special equipment for compact layout of actuators.

[0034] In some embodiments, for example Figure 1 and Figure 2 As shown, the differential bidirectional parallel four-rod synchronous combination hydraulic cylinder also includes a connector assembly. The connector assembly includes a first connector seat 3, a first connector pipe 4, a second connector seat 5, and a second connector pipe 6. The first connector seat 3 and the second connector seat 5 are installed separately on the first double-rod combination hydraulic cylinder. Both the first connector seat 3 and the second connector seat 5 are provided with connector oil ports. The first connector seat 3 is connected to the two oil inlet chambers in the first double-rod combination hydraulic cylinder and the two oil return chambers in the second double-rod combination hydraulic cylinder through the first connector pipe 4. The second connector seat 5 is connected to the two oil return chambers in the first double-rod combination hydraulic cylinder and the two oil inlet chambers in the second double-rod combination hydraulic cylinder through the second connector pipe 6.

[0035] The first connector 3 refers to an integrated oil circuit interface for centrally connecting the oil inlet and return chambers. Specifically, it can be implemented using a metal block structure with multiple internal flow channels, which are arranged in a crisscross pattern to achieve directional distribution of oil between the upper and lower hydraulic cylinders. The second connector 5 refers to another integrated interface that works with the first connector 3 to achieve reverse oil circuit control. Its internal flow channel layout is mirror-symmetrical to the first connector 3, ensuring complementary oil circuit switching logic between the upper and lower hydraulic cylinders. The first connector pipe 4 refers to a rigid or flexible conduit connecting the first connector 3 to the corresponding oil chambers of the upper and lower hydraulic cylinders. Specifically, it can be a high-pressure resistant metal rigid pipe or composite flexible hose, such as a steel pipe with an inner diameter of 8mm, and is sealed using a flange or compression fitting. The second connector pipe 6 has the same structure as the first connector pipe 4, but a different connection path, and is used to achieve reverse oil flow control. The connector port refers to a standardized hydraulic interface located on the outer surface of the connector for quick connection to an external oil source.

[0036] Specifically, when external hydraulic oil is input through the oil port of the first connector 3, the oil simultaneously enters the two inlet chambers of the first double-rod combination hydraulic cylinder via the first connector pipe 4, driving its piston rod to extend synchronously. Simultaneously, the two return chambers of the second double-rod combination hydraulic cylinder are connected through the same pipe to form a return channel, causing the corresponding piston rod to retract synchronously. When the oil flow direction switches to the second connector 5, the oil enters the return chamber of the first double-rod combination hydraulic cylinder through the second connector pipe 6, causing its piston rod to retract. Simultaneously, the inlet chamber of the second double-rod combination hydraulic cylinder receives pressurized oil, driving its piston rod to extend. This cross-oil circuit design achieves differential action of the upper and lower hydraulic cylinders through a single oil port control, forming a closed loop of oil between the two sets of hydraulic cylinders, eliminating the need for an additional independent return pipeline. The spaced installation method of the connectors avoids oil circuit interference; for example, the center-to-center distance between the two connectors is maintained at 1.5 times the width of the connector, ensuring sufficient space for pipeline layout.

[0037] Through the above technical solutions, this application effectively solves the problem of hydraulic system complexity caused by the combination of multiple hydraulic cylinders, and effectively reduces the space occupied by external hydraulic connection points and pipeline layout. The cross hydraulic circuit design enables the upper and lower hydraulic cylinders to form a force couple motion relationship, which can realize synchronous reverse deflection of the left and right wheels in the vehicle steering system. The sealing structure of the integrated joint assembly can meet the high reliability requirements of special equipment. The dual-port control method eliminates the need for an additional direction switching valve in the hydraulic system, effectively reducing system complexity.

[0038] In some embodiments, for example Figure 1 As shown, spherical bearings are installed on the lugs 1 at both ends of the first double-rod combined hydraulic cylinder and the lugs 1 at both ends of the second double-rod combined hydraulic cylinder.

[0039] Among them, a spherical plain bearing refers to a spherical sliding bearing capable of multi-degree-of-freedom rotation. Specifically, it can be implemented using a spherical contact structure with an inner and outer ring, adapting to load transmission in different directions through the relative rotation of the inner and outer rings. Earring 1 refers to an annular connecting component located at the end of the piston rod, specifically implemented using a forged or machined annular flange structure, used for connection to the main structural components via a pin.

[0040] Specifically, when the four piston rods of the hydraulic cylinder perform bidirectional synchronous extension and retraction, the spherical plain bearing allows the lugs 1 to undergo minute displacements in the axial, radial, and angular directions. During the extension or retraction of the piston rods, the inner and outer rings of the spherical plain bearing slide against each other through the spherical contact surface, compensating for changes in the connection point position caused by load direction offsets or structural component installation errors. Thus, the lugs 1 at the ends of the four piston rods can independently adjust their posture, avoiding interference between the movement trajectories of adjacent piston rods due to constraints in a single direction. Simultaneously, the rotational freedom of the spherical plain bearing can disperse local stress at the connection between the piston rod and the main structural component, preventing stress concentration caused by rigid connections.

[0041] Through the above technical solution, this application realizes a reliable connection between the four piston rods of the hydraulic cylinder and the main structural components when they extend and retract synchronously in different directions, eliminating stress concentration and motion interference caused by changes in the direction of motion, and improving the adaptability and service life of the hydraulic cylinder under complex working conditions.

[0042] In some embodiments, for example Figure 1 and Figure 2 As shown, sensor connector seats 10 are installed on the cylinder barrels 2 of both the first and second double-rod combination hydraulic cylinders, and proximity switches are installed on the sensor connector seats 10.

[0043] The sensor connector 10 refers to the mounting base fixed to the outer wall of the cylinder 2. Specifically, it can be a metal base with threaded holes or a snap-fit ​​structure, used to support the proximity switch and provide a stable mounting position. The proximity switch is a sensing device used to detect the position of the piston rod. Specifically, it can be an inductive or capacitive non-contact sensor that generates an electrical signal by sensing changes in the position of a metal trigger plate at the end of the piston rod or on the piston.

[0044] Specifically, when the hydraulic cylinder operates, the piston rod extends and retracts within the cylinder barrel 2. A proximity switch mounted on the sensor connector 10 detects the piston rod's travel distance non-contactly. For example, when the piston rod extends to a preset position, the proximity switch senses the trigger plate and outputs a signal. This signal is transmitted to the control system to trigger a locking action or switch the oil circuit direction. Both cylinder barrels 2 of the two dual-rod combination hydraulic cylinders are equipped with this detection structure, allowing the position of the four piston rods to be monitored independently. The fixed connection between the sensor connector 10 and the cylinder barrel 2 avoids detection deviations caused by vibration, while the detachable design of the proximity switch facilitates maintenance or replacement.

[0045] Through the above technical solution, this application solves the problem of difficulty in real-time monitoring of piston rod position during differential bidirectional synchronous extension and retraction of hydraulic cylinders, achieving accurate detection and feedback of the movement status of the four piston rods, thereby ensuring the coordination of synchronous actions and the reliability of positioning and locking. For example, in the steering system of special vehicles, this technology can effectively avoid steering asynchrony caused by piston rod position deviation, improving the accuracy and safety of system control.

[0046] Other configurations and operations of the differential bidirectional parallel four-rod synchronous combination hydraulic cylinder according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0047] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0048] Although embodiments of the invention have been shown and described, those skilled in the art will understand 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 claims and their equivalents.

Claims

1. A differential bidirectional parallel four-rod synchronous combination hydraulic cylinder, characterized in that, include: The first and second double-rod combined hydraulic cylinders are composed of two single-rod hydraulic cylinders sharing the same cylinder bottom and being combined into one unit in the axial direction. The first double-rod combination hydraulic cylinder and the second double-rod combination hydraulic cylinder are radially connected in parallel to form a four-rod hydraulic cylinder; Both the first and second double-rod combination hydraulic cylinders have an integral cylinder bottom in the middle. The integral cylinder bottom of the first double-rod combination hydraulic cylinder has a plug groove, and the integral cylinder bottom of the second double-rod combination hydraulic cylinder has a plug. The first and second double-rod combination hydraulic cylinders are connected in parallel through the engagement of the plug groove and the plug. The differential bidirectional parallel four-rod synchronous combined hydraulic cylinder further includes a connector assembly, which includes a first connector seat, a first connector pipe, a second connector seat, and a second connector pipe. The first connector seat and the second connector seat are installed separately on the first double-rod combined hydraulic cylinder. Both the first connector seat and the second connector seat are provided with connector oil ports. The first connector seat is connected to two oil inlet chambers in the first double-rod combined hydraulic cylinder and two oil return chambers in the second double-rod combined hydraulic cylinder through the first connector pipe. The second connector seat is connected to two oil return chambers in the first double-rod combined hydraulic cylinder and two oil inlet chambers in the second double-rod combined hydraulic cylinder through the second connector pipe.

2. The differential bidirectional parallel four-output synchronous combined hydraulic cylinder according to claim 1, characterized in that, The insertion slot is a cross-shaped square slot.

3. The differential bidirectional parallel four-output synchronous combined hydraulic cylinder according to claim 1, characterized in that, The integrated cylinder bottom is a square-round integrated cylinder bottom.

4. The differential bidirectional parallel four-output synchronous combined hydraulic cylinder according to claim 1, characterized in that, It also includes a connecting plate, which is disposed on the side of the four-rod hydraulic cylinder and fixedly connected to the first double-rod combined hydraulic cylinder and the second double-rod combined hydraulic cylinder, respectively.

5. The differential bidirectional parallel four-rod synchronous combination hydraulic cylinder according to claim 1, characterized in that, Both ends of the first double-rod combined hydraulic cylinder and the second double-rod combined hydraulic cylinder are equipped with spherical bearings.

6. The differential bidirectional parallel four-output synchronous combined hydraulic cylinder according to claim 1, characterized in that, Both the first and second double-rod combined hydraulic cylinders are equipped with sensor connectors, and proximity switches are installed on the sensor connectors.

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