Manual overload protection system

Abstract

The utility model provides a manual overload protection system which comprises an oil tank, a pilot overflow valve, a first switch valve, a motor and a first control valve group, a hydraulic pump is arranged on the oil tank and connected with a first port of the motor through an oil inlet pipeline, and a second port of the motor is connected with the oil tank through an oil return pipeline. A pilot-operated overflow valve is arranged between the oil inlet pipeline and the oil return pipeline, the oil inlet end of the pilot-operated overflow valve is connected with the oil inlet pipeline, and the oil outlet end of the pilot-operated overflow valve is connected with the oil return pipeline; the first control valve group comprises a first control switch valve, a first control reversing valve and a first control overflow valve; by means of the structure, under the emergency condition, the adjusting pressure of the overflow valve can be adjusted and relieved, and therefore the winch is controlled to quickly loosen the steel wire rope to achieve emergency rope abandoning.

Description

Technical Field

[0001] The utility model relates to the technical field of winch control systems, and particularly relates to a manual overload protection system. Background Art

[0002] A winch, also known as a hoist, is a common mechanical device. The winch winds a steel wire rope or a chain around a drum, and realizes the winding and unwinding of the steel wire rope through the rotation of the drum to lift or tow an object. Hydraulic winches are widely used in operation fields such as ocean engineering, construction, water conservancy projects, mines, etc., and are important auxiliary tools for the winding, lifting, and horizontal towing of equipment and materials. With the increase of the rated working conditions of lifting machinery and the complexity of the working environment, the requirements for the safety, stability, and controllability of hydraulic winches are getting higher and higher.

[0003] In the patent document with the Chinese patent application number 202323007055.9 and the publication date of July 2, 2024, a hydraulic system for a winch to store a cable is disclosed, which includes a storage winch motor, an oil tank, and a pilot-operated relief valve. The oil tank is provided with a first opening and a second opening. One end of the storage winch motor is connected to the first opening of the oil tank through a first oil circuit, and the other end of the storage winch motor is connected to the second opening of the oil tank through a second oil circuit. A pilot-operated relief valve is provided between the first oil circuit and the second oil circuit. The inlet end of the pilot-operated relief valve is connected to the first oil circuit, the outlet end of the pilot-operated relief valve is connected to the second oil circuit, and the control end of the pilot-operated relief valve is also connected to the first oil circuit; the hydraulic system in the above document enables the storage winch to control the stable rotation of the winch motor during rope winding, so that the cable maintains a constant tension state.

[0004] In the prior art such as this document, if during a lifting operation on a platform with a supply ship, the hook connected to the steel wire rope accidentally hooks on the supply ship and cannot be removed, at this time, because the supply ship is located at sea, due to the influence of wind and waves, the supply ship will move with the wind and waves. At this time, if the steel wire rope on the winch is not quickly released, the winch will be towed and damaged by the supply ship, resulting in an accident. If the wire rope is simply released by relieving the pressure through a pressure relief valve, when the adjustment pressure of the pressure relief valve is relatively large, it must reach the adjustment pressure of the pressure relief valve to relieve the pressure, thus it is impossible to ensure rapid wire rope release. Summary of the Invention

[0005] The utility model provides a manual overload protection system, which can adjust the adjustment pressure of the relief valve and relieve the adjustment pressure of the relief valve in an emergency, so as to control the winch to quickly release the steel wire rope to achieve emergency rope abandonment.

[0006] To achieve the above object, the technical solution of the present utility model is: a manual overload protection system, including an oil tank, a pilot-operated relief valve, a first switching valve, a first control valve group and a motor. A hydraulic pump is provided on the oil tank. The hydraulic pump is connected to the first port of the motor through an oil inlet pipeline. The second port of the motor is connected to the oil tank through an oil return pipeline. A pilot-operated relief valve is provided between the oil inlet pipeline and the oil return pipeline. The oil inlet end of the pilot-operated relief valve is connected to the oil inlet pipeline, and the oil outlet end of the pilot-operated relief valve is connected to the oil return pipeline. A first switching valve is provided on the oil return pipeline. The first control valve group includes a first control switching valve, a first control reversing valve and a first control relief valve. The P port and the T port of the first control reversing valve are connected to the oil tank. The A port of the first control reversing valve is connected to the control end of the first control switching valve. The first port of the first control switching valve is connected to the oil tank through the first control relief valve. The second port of the first control switching valve is connected to the control oil circuit of the pilot-operated relief valve. The relief pressure of the first control relief valve is less than the control pressure of the control oil circuit of the pilot-operated relief valve.

[0007] The second control end of the first switching valve is connected to the A end of the first switching valve through a first shuttle valve. The first port of the first switching valve is connected to the second port of the motor through an oil return pipeline. The second port of the first switching valve is connected to the oil tank through an oil return pipeline. The first control end of the first switching valve is connected to the first port and the second port of the first switching valve. The second control end of the first switching valve is connected to the oil tank. The first control end of the first switching valve controls the first port and the second port of the first switching valve to be communicated. The second control end of the first switching valve controls the first port and the second port of the first switching valve to be disconnected.

[0008] In the above structure, when taking in the rope, the oil tank outputs hydraulic oil into the oil inlet pipeline, then passes through the motor and enters the oil tank through the oil return pipeline to realize the operation of taking in the rope. At the same time, a first switching valve is provided on the oil return pipeline. When the motor rotates normally, the oil tank transports hydraulic oil to the motor through the oil inlet pipeline and flows into the oil return pipeline through the motor. The hydraulic oil in the oil return pipeline flows to the first control end of the first switching valve, thereby driving the first switching valve to change its direction and connect the first port and the second port. As a result, the oil return pipeline is connected to the oil tank, and the hydraulic oil can flow back to the oil tank to achieve circulation. When an incorrect operation of lifting a heavy object occurs, and at this time it is in the state of taking in the rope, manually make the first control reversing valve conduct. The first control reversing valve changes its direction to connect the A end and the P end. The oil tank outputs hydraulic oil to the control end of the first control switching valve through the first control reversing valve, causing the first control switching valve to change its direction and connect the first port and the second port of the first control switching valve. As a result, the control hydraulic oil of the control oil circuit of the pilot-operated relief valve is depressurized and flows back to the oil tank through the first control relief valve. Thus, the regulating pressure of the pilot-operated relief valve becomes lower. Since the oil pressure in the oil inlet pipeline is greater than the regulating pressure of the pilot-operated relief valve, the pilot-operated relief valve is driven to open. As a result, the hydraulic oil in the oil inlet pipeline is depressurized to the oil return pipeline through the pilot-operated relief valve, thereby increasing the oil pressure on the oil return pipeline and making the oil pressure at the end of the motor connected to the oil return pipeline greater than the oil pressure at the end of the motor connected to the oil inlet pipeline. And due to the overflow effect of the pilot-operated relief valve, a circulation loop is formed between the oil inlet pipeline, the oil return pipeline and the motor through the pilot-operated relief valve. The oil tank continues to output hydraulic oil to the oil inlet pipeline, and then the hydraulic oil in the circulation loop continuously increases, thereby increasing the pressure difference between the two ends of the motor, and then increasing the rotational speed of the motor to achieve rapid rope release. Thus, when rapid rope release is required, only by manually pressing the first control reversing valve to change its direction, the first switching valve can be controlled to open and the pilot-operated relief valve can be depressurized at the same time, so that a rapid formation of the internal circulation oil circuit can be achieved, ensuring rapid rope release.

[0009] Further, a second switching valve is provided between the oil inlet end of the pilot-operated relief valve and the oil inlet pipeline. The first port of the second switching valve is connected to the oil inlet pipeline, and the second port of the second switching valve is connected to the oil inlet end of the pilot-operated relief valve.

[0010] With the above settings, by providing the second switching valve, the oil circuit between the oil inlet pipeline and the pilot-operated relief valve is opened only when the pilot-operated relief valve needs to be used, which is convenient for controlling the hydraulic system.

[0011] Further, a balance valve group is provided on the oil inlet pipeline. The balance valve group includes a balance overflow valve and a balance check valve. The oil inlet end of the balance overflow valve is connected to the first port of the motor through the oil inlet pipeline, and the oil outlet end of the balance overflow valve is connected to the hydraulic pump through the oil inlet pipeline. The oil inlet end of the balance check valve is connected to the oil outlet end of the balance overflow valve, and the oil outlet end of the balance check valve is connected to the oil inlet end of the balance overflow valve.

[0012] With the above settings, by providing the balance valve group, the hydraulic oil output of the oil inlet pipeline is made stable.

[0013] Further, a brake valve is also provided on the motor. The control end of the brake valve is connected to the oil inlet pipeline and the oil outlet pipeline through a brake reversing valve. The P port of the brake reversing valve is connected to the fuel tank, the A port of the brake reversing valve is connected to the control end of the brake valve, and the control end of the brake reversing valve is connected to the oil inlet pipeline and the oil outlet pipeline.

[0014] With the above settings, by connecting the control end of the brake valve reversing valve to the oil inlet pipeline and the oil outlet pipeline, when starting the winch, the hydraulic oil in the oil inlet pipeline and the oil outlet pipeline flows to the control end of the brake reversing valve and controls the brake reversing valve to change direction so that the A port is connected to the P port, thereby enabling the hydraulic oil output from the fuel tank to flow to the control end of the brake valve, thus driving the brake valve to open and facilitating the rotation of the motor.

[0015] Further, a spring is also provided on the second control end of the first switch valve. The pressure of the hydraulic oil at the second control end plus the pressure of the spring is greater than the pressure of the hydraulic oil at the first control end of the first switch valve.

[0016] With the above settings, by providing the spring, when closing the first switch valve, the hydraulic oil pressure flowing from the fuel tank into the second control end of the first switch valve plus the elastic force of the spring overcomes the hydraulic oil pressure at the first control end of the first switch valve, thereby driving the first switch valve to close, making the hydraulic oil unable to flow back to the fuel tank through the oil return pipeline.

[0017] Further, a first shuttle valve is provided between the second control end of the first switch valve and the A port of the first control reversing valve. The first port of the first shuttle valve is connected to the A port of the first control reversing valve, the second port of the first shuttle valve is connected to the fuel tank, and the third port of the first shuttle valve is connected to the second control end of the first switch valve.

[0018] With the above settings, by providing the first shuttle valve between the second control end of the first switch valve and the A port of the first control reversing valve, the hydraulic oil flowing through the first control reversing valve to the second control end of the first switch valve and the hydraulic oil flowing from the fuel tank to the second control end of the first switch valve will not conflict with each other. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the hydraulic system of the present utility model.

[0020] Figure 2 is Figure 1 The enlarged view of position A in

[0021] Figure 3 is Figure 1 The enlarged view of position B in Specific embodiments

[0022] The present utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] As Figures 1-3 shown, a manual overload protection system includes an oil tank 1, a pilot-operated relief valve 2, a first switching valve 3, a motor 4, and a first control valve group. A hydraulic pump (not shown in the figure) is provided on the oil tank 1. The hydraulic pump is connected to the first port 41 of the motor 4 through an oil inlet pipeline 11. The second port 42 of the motor 4 is connected to the oil tank 1 through an oil return pipeline 12. A pilot-operated relief valve 2 is provided between the oil inlet pipeline 11 and the oil return pipeline 12. The oil inlet end of the pilot-operated relief valve 2 is connected to the oil inlet pipeline 11, and the oil outlet end of the pilot-operated relief valve 2 is connected to the oil return pipeline 12. A first switching valve 3 is provided on the oil return pipeline 12. The first port of the first switching valve 3 is connected to the second port 42 of the motor 4 through the oil return pipeline 12. The second port of the first switching valve 3 is connected to the oil tank 1 through the oil return pipeline 12. The first control end 31 of the first switching valve 3 is connected to the first port and the second port of the first switching valve 3. The second control end 32 of the first switching valve 3 is connected to the oil tank. The first control end 31 of the first switching valve 3 controls the first port and the second port of the first switching valve 3 to communicate, and the second control end 32 of the first switching valve 3 controls the first port and the second port of the first switching valve 3 to disconnect.

[0024] The first control valve group includes a first control switching valve 81, a first control directional valve 82, and a first control relief valve 83. The P port and the T port of the first control directional valve 82 are connected to the oil tank 1. The A port of the first control directional valve 82 is connected to the control end 811 of the first control switching valve 81. The first port of the first control switching valve 81 is connected to the oil tank 1 through the first control relief valve 83. The second port of the first control switching valve 81 is connected to the control oil circuit 20 of the pilot-operated relief valve 2. The relief pressure of the first control relief valve 83 is less than the control pressure of the control oil circuit 20 of the pilot-operated relief valve 2.

[0025] In this embodiment, the control end 821 of the first control directional valve is connected to a control button (not shown in the figure) in the crane cab through an external circuit. When an emergency occurs, the staff in the cab presses the control button to drive the first control directional valve to switch.

[0026] A first shuttle valve 84 is provided between the second control end 32 of the first switching valve 3 and the A port of the first control reversing valve 82. The first port 841 of the first shuttle valve 84 is connected to the A port of the first control reversing valve 82, the second port 842 of the first shuttle valve 84 is connected to the oil tank 1, and the third port 843 of the first shuttle valve 84 is connected to the second control end 32 of the first switching valve 3.

[0027] By providing the first shuttle valve 84 between the second control end 32 of the first switching valve 3 and the A port of the first control reversing valve 82. When the rope is being wound in under normal conditions, the hydraulic oil in the control oil tank 1 enters through the second port 842 of the first shuttle valve 84. Since the first port 841 of the first shuttle valve 84 cannot supply oil because the first control switching valve 82 is in the closed state, the hydraulic oil in the oil tank 1 enters the second control end 32 of the first switching valve 3 through the second port 842, causing the first switching valve 3 to close, thereby enabling the rope-winding operation to be closed during rope winding. When an emergency rope winding is required, since the first control switching valve 82 is in the conducting state, the hydraulic oil in the oil tank 1 enters the first port 841 of the first shuttle valve 84 through the first control switching valve 82 and then flows into the control end of the first switching valve 3 to cause the first switching valve 3 to close, thereby realizing the emergency rope winding. And it ensures that the hydraulic oil flowing from the first control reversing valve 82 to the second control end 32 of the first switching valve 3 does not conflict with the hydraulic oil flowing from the oil tank 1 to the second control end 32 of the first switching valve 3.

[0028] A second switching valve 21 is provided between the oil inlet end of the pilot-operated relief valve 2 and the oil inlet pipe. The first port of the second switching valve 21 is connected to the oil inlet pipe 11, and the second port of the second switching valve 21 is connected to the oil inlet end of the pilot-operated relief valve 2. By providing the second switching valve 21, the oil circuit between the oil inlet pipe 11 and the pilot-operated relief valve 2 is opened only when the pilot-operated relief valve 2 needs to be used, thus facilitating the control of the hydraulic system.

[0029] A balance valve group 5 is provided on the oil inlet pipe 11. The balance valve group 5 includes a balance relief valve 51 and a balance check valve 52. The oil inlet end of the balance relief valve 51 is connected to the first port 41 of the motor 4 through the oil inlet pipe 11, the oil outlet end of the balance relief valve 51 is connected to the hydraulic pump through the oil inlet pipe 11, the oil inlet end of the balance check valve 52 is connected to the oil outlet end of the balance relief valve 51, and the oil outlet end of the balance check valve 52 is connected to the oil inlet end of the balance relief valve 51. By providing the balance valve group 5, the hydraulic oil output of the oil inlet pipe 11 is stabilized.

[0030] As Figure 1As shown, a brake valve 43 is further provided on the motor 4. The control end of the brake valve 43 is connected to the oil inlet pipe and the oil outlet pipe through a brake reversing valve 44. The P end of the brake reversing valve 44 is connected to the fuel tank. The A end of the brake reversing valve is connected to the control end of the brake valve. The control end K of the brake reversing valve 44 is connected to the oil inlet pipe 11 and the oil outlet pipe 12. By connecting the control end K of the brake valve reversing valve 44 to the oil inlet pipe 11 and the oil outlet pipe 12, when starting the winch, the hydraulic oil in the oil inlet pipe 11 and the oil outlet pipe 12 flows to the control end of the brake reversing valve 44 and controls the brake reversing valve 44 to reverse, so that the A end is communicated with the P end, thereby enabling the hydraulic oil output from the fuel tank 1 to flow to the control end of the brake valve 43, thereby driving the brake valve 43 to open and facilitating the rotation of the motor 4.

[0031] As Figure 2 shown, a spring 33 is further provided on the second control end 32 of the first switch valve 3. The hydraulic oil pressure at the second control end 32 plus the pressure of the spring 33 is greater than the hydraulic oil pressure at the first control end 31 of the first switch valve 3. By providing the spring 33, when closing the first switch valve 3, the hydraulic oil pressure in the hydraulic oil flowing from the fuel tank 1 into the second control end 32 of the first switch valve 3 plus the elastic force of the spring 33 overcomes the hydraulic oil pressure at the first control end 31 of the first switch valve 3, thereby driving the first switch valve 3 to close, so that the hydraulic oil cannot flow back to the fuel tank through the oil return pipe 12.

[0032] Working principle of the utility model: When taking in the rope, the oil tank 1 outputs hydraulic oil, which enters the oil inlet pipeline 11 through the balance check valve 52, then passes through the motor 4 and enters the oil tank 1 through the oil return pipeline 12 to realize the rope-taking-in operation. At the same time, a first switching valve 3 is provided on the oil return pipeline 12. When the motor 4 rotates normally, the oil tank 1 transports hydraulic oil to the motor 4 through the oil inlet pipeline 11 and flows into the oil return pipeline 12 through the motor 4. The hydraulic oil in the oil return pipeline 12 flows to the first control end 31 of the first switching valve 3, thereby driving the first switching valve 3 to change its direction and connect the first port and the second port. As a result, the oil return pipeline 12 is connected to the oil tank, and the hydraulic oil can flow back to the oil tank 1 to realize circulation. When an error occurs in lifting a heavy object while taking in the rope, manually make the first control reversing valve conduct. The first control reversing valve 82 changes its direction to connect the A end and the P end. The oil tank outputs hydraulic oil to the control end 811 of the first control switching valve 81 through the first control reversing valve 82, causing the first control switching valve 81 to change its direction and connect the first port and the second port of the first control switching valve 81. As a result, the control hydraulic oil of the control oil circuit 20 of the pilot-operated relief valve 2 is depressurized and flows back to the oil tank through the first control relief valve 83. Thus, the regulating pressure of the pilot-operated relief valve 2 becomes lower. Since the oil pressure in the oil inlet pipeline 11 is greater than the regulating pressure of the pilot-operated relief valve 2, the pilot-operated relief valve 2 is driven to open. As a result, the hydraulic oil in the oil inlet pipeline 11 is depressurized to the oil return pipeline 12 through the pilot-operated relief valve 2, thereby increasing the oil pressure on the oil return pipeline 12 and making the oil pressure at the end of the motor 4 connected to the oil return pipeline 12 greater than the oil pressure at the end of the motor connected to the oil inlet pipeline 11. And due to the overflow effect of the pilot-operated relief valve 2, a circulation loop is formed among the oil inlet pipeline, the oil return pipeline and the motor through the pilot-operated relief valve. The oil tank continues to output hydraulic oil to the oil inlet pipeline, further increasing the hydraulic oil in the circulation loop, thereby increasing the pressure difference between the two ends of the motor 4, and further increasing the rotational speed of the motor 4 to realize rapid rope release. Thus, when rapid rope release is required, only by manually pressing the first control reversing valve to change its direction, the first switching valve can be controlled to open and the pilot-operated relief valve can be depressurized at the same time, so that a rapid formation of the internal circulation oil circuit can be realized, ensuring rapid rope release.

Claims

1. A manual overload protection system, characterized in that: It includes an oil tank, a pilot relief valve, a first switch valve, a first control valve group and a motor. A hydraulic pump is provided on the oil tank. The hydraulic pump is connected to a first port of the motor through an oil inlet pipeline. The second port of the motor is connected to the oil tank through an oil return pipeline. A pilot relief valve is provided between the oil inlet pipeline and the oil return pipeline. The oil inlet end of the pilot relief valve is connected to the oil inlet pipeline, and the oil outlet end of the pilot relief valve is connected to the oil return pipeline. A first switch valve is provided on the oil return pipeline. The first control valve group includes a first control switch valve, a first control reversing valve and a first control relief valve, the P end and the T end of the first control reversing valve are connected to the oil tank, the A end of the first control reversing valve is connected to the control end of the first control switch valve, the first port of the first control switch valve is connected to the oil tank through the first control relief valve, the second port of the first control switch valve is connected to the control oil circuit of the pilot relief valve, and the relief pressure of the first control relief valve is less than the control pressure of the control oil circuit of the pilot relief valve; The second control end of the first switch valve is connected to the A end of the first switch valve through the first shuttle valve, the first port of the first switch valve is connected to the second port of the motor through the return oil pipeline, the second port of the first switch valve is connected to the oil tank through the return oil pipeline, the first control end of the first switch valve connects the first port and the second port of the first switch valve, the second control end of the first switch valve is connected to the oil tank, the first control end of the first switch valve controls the first port and the second port of the first switch valve to be connected, and the second control end of the first switch valve controls the first port and the second port of the first switch valve to be disconnected.

2. A manual overload protection system according to claim 1, characterized in that: A second switch valve is provided between the oil inlet end of the pilot relief valve and the oil inlet pipeline, a first port of the second switch valve is connected to the oil inlet pipeline, and a second port of the second switch valve is connected to the oil inlet end of the pilot relief valve.

3. A manual overload protection system according to claim 1, characterized in that: A balancing valve group is provided on the oil inlet pipeline, and the balancing valve group includes a balancing overflow valve and a balancing check valve. The oil inlet end of the balancing overflow valve is connected to the first port of the motor through the oil inlet pipeline, and the oil outlet end of the balancing overflow valve is connected to the hydraulic pump through the oil inlet pipeline. The oil inlet end of the balancing check valve is connected to the oil outlet end of the balancing overflow valve, and the oil outlet end of the balancing check valve is connected to the oil inlet end of the balancing overflow valve.

4. A manual overload protection system according to claim 1, characterized in that: A brake valve is also provided on the motor, and the control end of the brake valve is connected to the oil inlet pipeline and the oil outlet pipeline through the brake reversing valve. The P end of the brake reversing valve is connected to the oil tank, and the A end of the brake reversing valve is connected to the control end of the brake valve. The control end of the brake reversing valve is connected to the oil inlet pipeline and the oil outlet pipeline.

5. A manual overload protection system according to claim 1, characterized in that: A spring is also provided on the second control end of the first switch valve, and the hydraulic oil pressure at the second control end plus the pressure of the spring is greater than the hydraulic oil pressure at the first control end of the first switch valve.

6. A manual overload protection system according to claim 1, characterized in that: A first shuttle valve is provided between the second control end of the first switch valve and the A end of the first control reversing valve, the first port of the first shuttle valve is connected to the A end of the first control reversing valve, the second port of the first shuttle valve is connected to the oil tank, and the third port of the first shuttle valve is connected to the second control end of the first switch valve.

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