Coil loading and unloading trolley control system

Abstract

The utility model belongs to the technical field of rolling of cold rolling mills, and particularly relates to a coil loading and unloading trolley control system. The device comprises a pressure reducing valve, a proportional reversing valve, a pressure relay, a coil loading and unloading trolley oil cylinder, a pressure reducing valve oil drainage port pressure adjusting mechanism, an oil supply oil way, an oil return oil way, an oil drainage oil way and a controller, an oil return opening and an oil supply opening are formed in the coil feeding and discharging trolley oil cylinder, the oil supply opening is communicated with an oil supply opening P of the oil supply oil way through a pressure relay, a proportional reversing valve and a pressure reducing valve in sequence, and the oil return opening is communicated with an oil return opening T of the oil return oil way through the proportional reversing valve; the pressure reducing valve is communicated with an oil drainage port L of the oil drainage path through a pressure reducing valve oil drainage port pressure adjusting mechanism; the controller is in electric signal connection with the proportional reversing valve, the pressure relay and the pressure reducing valve oil drainage port pressure adjusting mechanism. According to the utility model, the coil loading and unloading time is saved, the stability of the steel coil in the coil loading and unloading process is ensured, and the damage to the winding drum caused by overlarge pressure is avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of cold rolling mill rolling, and in particular relates to a coil loading and unloading trolley control system. Background Art

[0002] In a cold rolling mill, the steel coil needs to be loaded from the coil storage position onto the uncoiler, and the strip needs to be unloaded from the coiler. The rise and fall of the steel coil in this process is achieved by the rise and fall of the oil cylinder on the coil loading and unloading trolley. Ordinary hydraulic circuits can realize the rise and fall of the coil loading and unloading trolley driven by the hydraulic cylinder, but the pressure and flow remain unchanged during the rise and fall process. When the speed is too high, the steel coil will be unstable, increasing the possibility of accidents such as steel coil tipping. When the speed is too low, the time for loading and unloading will be longer, and the efficiency of loading and unloading will be reduced. If the pressure remains unchanged, the coil loading and unloading trolley will easily damage the reel when improper operation causes it to hit the reel. If the speed remains unchanged during the descent process, the unloading efficiency will also be low. Utility Model Content

[0003] The utility model provides a control system for a reel loading and unloading trolley, and aims to provide a control system and a control method which can automatically switch pressure and speed according to different working conditions, improve the efficiency of reel loading and unloading, and avoid damaging the reel.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0005] A control system for a coil loading and unloading trolley comprises a pressure reducing valve, a proportional reversing valve, a pressure relay, a coil loading and unloading trolley cylinder, a pressure regulating mechanism for an oil drain port of the pressure reducing valve, an oil supply circuit, an oil return circuit, an oil drain circuit and a controller; the pressure regulating mechanism for the oil drain port of the pressure reducing valve comprises an electromagnetic reversing valve passage and an overflow valve passage connected in parallel; an oil return port and an oil supply port are arranged on the coil loading and unloading trolley cylinder, the oil supply port is connected to an oil supply port P of the oil supply circuit via a pressure relay, a proportional reversing valve and a pressure reducing valve in sequence, and the oil return port is connected to an oil return port T of the oil return circuit via a proportional reversing valve; the pressure reducing valve is connected to an oil drain port L of the oil drain circuit via an electromagnetic reversing valve passage or an overflow valve passage in the pressure regulating mechanism for the oil drain port of the pressure reducing valve; the controller is connected to electrical signals of the proportional reversing valve, the pressure relay and the pressure regulating mechanism for the oil drain port of the pressure reducing valve, respectively.

[0006] It also includes a double hydraulically controlled one-way valve; the double hydraulically controlled one-way valve is installed between the pressure relay and the proportional reversing valve, and between the oil return port of the oil cylinder of the loading and unloading trolley and the proportional reversing valve.

[0007] It also includes a superimposed overflow valve; the superimposed overflow valve is connected between the pressure relay and the proportional reversing valve, and is communicated with the oil return port T of the oil return circuit.

[0008] The electromagnetic reversing valve passage comprises a first oil circuit and an electromagnetic reversing valve, and the electromagnetic reversing valve is connected to the first oil circuit.

[0009] The overflow valve passage includes a second oil circuit and an overflow valve, and the overflow valve is connected to the second oil circuit. Beneficial Effects

[0010] (1) During the winding process, the utility model can realize automatic switching between the high-speed rise of the low-pressure oil cylinder in the plug chamber and the low-speed rise of the high-pressure oil cylinder in the plug chamber according to different stages of the winding process, thereby saving the winding time, ensuring the stability of the steel coil during the winding process, and avoiding damage to the reel due to excessive pressure.

[0011] (2) During the unloading process, the utility model realizes the automatic switching between the low-pressure and low-speed processes of the cylinder rod chamber and the low-pressure and high-speed processes of the cylinder rod chamber, thereby saving the unloading time and improving the production rhythm.

[0012] (3) The double hydraulically controlled one-way valves in the utility model can be used to lock the cylinder of the upper unloading trolley when necessary.

[0013] (4) The arrangement of the superimposed relief valve in the utility model limits the pressure of the cylinder plug chamber of the coil loading and unloading trolley, thereby ensuring the safe implementation of the coil loading or unloading process.

[0014] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the utility model in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 The utility model is a schematic diagram of a hydraulic system for controlling a coil loading and unloading trolley.

[0017] In the figure: 1. Pressure reducing valve; 2. Proportional reversing valve; 3. Double hydraulically controlled non-return valve; 4. Superimposed relief valve; 5. Relief valve; 6. Solenoid reversing valve; 7. Pressure relay; 8. Oil cylinder for loading and unloading trolley; P is the oil supply port; T is the oil return port; L is the oil drain port. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model. Embodiment 1

[0019] according to Figure 1 A control system for a coil loading and unloading trolley shown in the figure comprises a pressure reducing valve 1, a proportional reversing valve 2, a pressure relay 7, a coil loading and unloading trolley cylinder 8, a pressure regulating mechanism for an oil drain port of the pressure reducing valve, an oil supply oil circuit, an oil return oil circuit, an oil drain oil circuit and a controller; the pressure regulating mechanism for the oil drain port of the pressure reducing valve comprises an electromagnetic reversing valve passage and an overflow valve passage connected in parallel; an oil return port and an oil supply port are arranged on the coil loading and unloading trolley cylinder 8, the oil supply port is connected to an oil supply port P of the oil supply oil circuit through the pressure relay 7, the proportional reversing valve 2 and the pressure reducing valve 1 in sequence, and the oil return port is connected to an oil return port T of the oil return oil circuit through the proportional reversing valve 2; the pressure reducing valve 1 is connected to an oil drain port L of the oil drain oil circuit through an electromagnetic reversing valve passage or an overflow valve passage in the pressure regulating mechanism for the oil drain port of the pressure reducing valve; the controller is respectively connected to electrical signals of the proportional reversing valve 2, the pressure relay 7 and the pressure regulating mechanism for the oil drain port of the pressure reducing valve.

[0020] The pressure reducing valve 1 in this embodiment is used to adjust the pressure in the plug cavity of the oil cylinder 8 of the upper and lower coil trolley; the proportional reversing valve 2 is used to control the movement direction and speed of the oil cylinder 8 of the upper and lower coil trolley; the overflow valve 5 is used to achieve a high back pressure at the oil drain port of the pressure reducing valve 1; the pressure relay 7 is used to detect and send a signal for the plug cavity pressure of the oil cylinder 8 of the upper and lower coil trolley; the oil cylinder 8 of the upper and lower coil trolley is used to drive the upper and lower coil trolley to rise and fall.

[0021] In actual use, during the winding process, when the trolley rises and before it contacts the steel coil, the electromagnetic reversing valve passage in the pressure adjustment mechanism of the oil drain port of the pressure reducing valve is in an energized state. At this time, the oil drain port of the pressure reducing valve 1 is connected with the oil drain port L of the oil drain circuit through the electromagnetic reversing valve passage. The plug chamber pressure of the oil cylinder 8 of the winding trolley is the set pressure of the pressure reducing valve 1. The controller controls the proportional reversing valve 2 to be in a wide opening state, so that the flow rate passing through is larger, the winding trolley oil cylinder 8 rises faster, and the winding trolley is in a high-speed state of the plug chamber low-pressure cylinder, which saves the rising time of the trolley. When the coiling trolley rises and contacts the steel coil, due to the load, the pressure of the plug chamber of the upper and lower coil trolley cylinder 8 increases. When the plug chamber pressure reaches the first pressure setting value of the pressure relay 7, the pressure relay 7 sends a No. 1 high pressure signal to the controller. The controller controls the electromagnetic reversing valve passage in the pressure adjustment mechanism of the oil drain port of the pressure reducing valve to switch to a power-off state. The oil drain port of the pressure reducing valve 1 is connected to the oil drain port L of the oil drain oil circuit after passing through the overflow valve passage. At this time, the outlet pressure of the pressure reducing valve 1 is the set pressure of the pressure reducing valve 1 plus the set pressure of the overflow valve passage, and the plug chamber pressure of the upper and lower coil trolley cylinder 8 is switched to a high pressure state; at this time, the proportional reversing valve 2 is switched to a small opening state, and the flow rate is small, so the upper and lower coil trolley cylinder 8 rises at a low speed. At this time, it is a low-speed state of the plug chamber high-pressure cylinder, and the rising process of the upper and lower coil trolley is stable until the steel coil is safely and stably lifted to the set position. During the unloading process, the upper unloading trolley 8 descends and the rod chamber is in an oil supply state; when the steel coil has not fallen to the unloading position, the weight of the coil acts on the oil cylinder 8 of the upper unloading trolley, which is equivalent to increasing the pressure in the rod chamber, and the back pressure of the plug chamber also increases. At this time, the second pressure setting point of the pressure relay 7 sends a No. 2 high pressure signal to the controller, and the controller controls the proportional reversing valve 2 to a small opening state, so that the flow rate becomes smaller, and the upper unloading trolley descends at a low speed; when the steel coil falls to the unloading position, the back pressure of the plug chamber is reduced due to the lack of the pressure of the coil weight, and the No. 2 high pressure signal of the pressure relay 7 disappears. At this time, the controller controls the proportional reversing valve 2 to switch to a large opening state, so that the flow rate becomes larger, and the upper unloading trolley quickly descends to the bottom position.

[0022] During the winding process, the utility model can realize the automatic switching of the low-pressure oil cylinder in the plug chamber of the oil cylinder during the winding process at a high speed and the high-pressure oil cylinder in the plug chamber at a low speed according to the different stages of the winding process, saving the winding time, ensuring the stability of the steel coil during the winding process, and avoiding the damage to the reel due to excessive pressure. During the unwinding process, the utility model realizes the automatic switching of the low-pressure oil cylinder in the rod chamber of the oil cylinder at a low speed and the high-pressure oil cylinder in the rod chamber, saving the unwinding time and improving the production rhythm. Embodiment 2

[0023] according to Figure 1The control system of a coil loading and unloading trolley shown in the figure is different from that of the first embodiment in that it also includes a double hydraulically controlled one-way valve 3; the double hydraulically controlled one-way valve 3 is installed between the pressure relay 7 and the proportional reversing valve 2, and between the oil return port of the coil loading and unloading trolley cylinder 8 and the proportional reversing valve 2.

[0024] Furthermore, it also includes a superimposed relief valve 4; the superimposed relief valve 4 is connected to the oil circuit between the pressure relay 7 and the proportional reversing valve 2, and is communicated with the oil return port T of the oil return circuit.

[0025] The double hydraulically controlled one-way valve 3 in this embodiment is used to lock the oil cylinder 8 of the upper unloading trolley.

[0026] The stacked relief valve 4 in this embodiment is used to limit the pressure of the plug chamber of the oil cylinder 8 of the upper unloading trolley.

[0027] In actual use, when the oil cylinder needs to stop at a certain position, the proportional reversing valve 2 is in a state where the control signal is zero, i.e., the middle position. At this time, the double hydraulically controlled one-way valve 3 plays a role to lock the oil cylinder.

[0028] When an accident occurs and causes the pressure in the oil cylinder plug chamber to exceed the set pressure of the superimposed relief valve 4, the superimposed relief valve 4 will play a role to protect the oil cylinder 8 and equipment of the winding trolley. Embodiment 3

[0029] according to Figure 1 The control system for a coil loading and unloading trolley shown in the figure is different from that of the first embodiment in that the electromagnetic reversing valve passage includes a first oil circuit and an electromagnetic reversing valve 6, and the electromagnetic reversing valve 6 is connected to the first oil circuit.

[0030] Furthermore, the overflow valve passage includes a second oil circuit and an overflow valve 5 , and the overflow valve 5 is connected to the second oil circuit.

[0031] The overflow valve 5 in this embodiment is used to achieve high back pressure at the oil drain port of the pressure reducing valve 1 ; the electromagnetic reversing valve 6 is used to switch the back pressure at the oil drain port of the pressure reducing valve 1 .

[0032] In actual use, during the winding process, when the trolley rises and before it contacts the steel coil, the electromagnetic reversing valve 6 is in an energized state. At this time, the oil drain port of the pressure reducing valve 1 is connected with the oil drain port L of the oil drain circuit through the electromagnetic reversing valve 6. The plug chamber pressure of the oil cylinder 8 of the winding trolley is the set pressure of the pressure reducing valve 1. The controller controls the proportional reversing valve 2 to be in a large opening state, so that the flow rate passing through is larger, the winding trolley oil cylinder 8 rises faster, and the winding trolley is in a high-speed state of the plug chamber low-pressure oil cylinder, which saves the trolley rising time. When the coiling trolley rises and contacts the steel coil, due to the load, the pressure in the plug chamber of the oil cylinder 8 of the coiling trolley increases. When the plug chamber pressure reaches the first pressure setting value of the pressure relay 7, the pressure relay 7 sends a No. 1 high pressure signal to the controller. The controller controls the electromagnetic reversing valve 6 to switch to the power-off state. The oil drain port of the pressure reducing valve 1 is connected to the oil drain port L of the oil drain circuit after passing through the relief valve 5. At this time, the outlet pressure of the pressure reducing valve 1 is the set pressure of the pressure reducing valve 1 plus the set pressure of the relief valve 5 in the relief valve passage. The plug chamber pressure of the oil cylinder 8 of the coiling trolley is switched to a high pressure state. At this time, the proportional reversing valve 2 is switched to a small opening state, and the flow rate is small. The rising speed of the oil cylinder 8 of the coiling trolley slows down. At this time, it is in the low speed state of the plug chamber high pressure cylinder. The rising process of the coiling trolley is stable until the steel coil is safely and stably lifted to the set position. During the unloading process, the upper unloading trolley 8 descends and the rod chamber is in an oil supply state; when the steel coil has not fallen to the unloading position, the weight of the coil acts on the oil cylinder 8 of the upper unloading trolley, which is equivalent to increasing the pressure in the rod chamber, and the back pressure of the plug chamber also increases. At this time, the second pressure setting point of the pressure relay 7 sends a No. 2 high pressure signal to the controller, and the controller controls the proportional reversing valve 2 to a small opening state, so that the flow rate becomes smaller, and the upper unloading trolley descends at a low speed; when the steel coil falls to the unloading position, the back pressure of the plug chamber is reduced due to the lack of the pressure of the coil weight, and the No. 2 high pressure signal of the pressure relay 7 disappears. At this time, the controller controls the proportional reversing valve 2 to switch to a large opening state, so that the flow rate becomes larger, and the upper unloading trolley quickly descends to the bottom position. Embodiment 4

[0033] according to Figure 1 The control system of a coil loading and unloading trolley shown in the figure is different from that of the first embodiment in that it also includes a double hydraulically controlled one-way valve 3 and a superimposed overflow valve 4; the superimposed overflow valve 4 is connected between the pressure relay 7 and the double hydraulically controlled one-way valve 3, and is communicated with the return oil port T of the return oil circuit; the double hydraulically controlled one-way valve 3 is installed between the superimposed overflow valve 4 and the proportional reversing valve 2, and between the return oil port of the coil loading and unloading trolley cylinder 8 and the proportional reversing valve 2; the electromagnetic reversing valve passage includes a first oil circuit and an electromagnetic reversing valve 6, and the electromagnetic reversing valve 6 is connected to the first oil circuit; the overflow valve passage includes a second oil circuit and an overflow valve 5, and the overflow valve 5 is connected to the second oil circuit.

[0034] The utility model can realize automatic switching between high-speed rising of the low-pressure oil cylinder in the plug chamber and low-speed rising of the high-pressure oil cylinder in the plug chamber during the winding process according to different stages of the winding process, thereby saving the winding time, ensuring the stability of the steel coil during the winding process and avoiding damage to the reel due to excessive pressure.

[0035] The utility model realizes the automatic switching of the process of low-pressure oil cylinder and low speed of the oil cylinder rod chamber and the process of low-pressure oil cylinder and high speed of the oil cylinder rod chamber during the unloading process, thus saving the unloading time and improving the production rhythm.

[0036] The double hydraulically controlled one-way valves in the utility model can be arranged to lock the oil cylinder of the coil loading and unloading trolley when needed, thus ensuring the stable implementation of the coil loading or unloading process.

[0037] The arrangement of the superimposed relief valve in the utility model realizes the limitation of the plug cavity pressure of the oil cylinder of the coil loading and unloading trolley, thereby ensuring the safe implementation of the coil loading or unloading process. Embodiment 5

[0038] Reference Figure 1 A coil loading and unloading trolley control method adopts a coil loading and unloading trolley control system, comprising the following steps:

[0039] Step 1. Select the type of operation process;

[0040] If you choose the roll-up process, go to step 2; if you choose the roll-down process, go to step 3;

[0041] Step 2: Before the trolley rises and contacts the steel coil, the electromagnetic reversing valve 6 in the electromagnetic reversing valve passage in the pressure adjustment mechanism of the oil drain port of the pressure reducing valve is in an energized state. At this time, the oil drain port of the pressure reducing valve 1 is connected with the oil drain port L of the oil drain circuit through the electromagnetic reversing valve 6. The plug chamber pressure of the oil cylinder 8 of the upper and lower coil trolley is the set pressure of the pressure reducing valve 1. The controller controls the proportional reversing valve 2 to be in a wide opening state, and the flow rate is large, so that the oil cylinder 8 of the upper and lower coil trolley rises rapidly. After contacting the steel coil, the plug chamber pressure of the oil cylinder 8 of the upper and lower coil trolley increases. When the plug chamber pressure reaches the first pressure setting value of the pressure relay 7, the pressure relay 7 sends a No. 1 high pressure signal to the controller, and the controller controls the pressure reducing The electromagnetic reversing valve 6 in the valve oil drain port pressure adjustment mechanism is switched to the power-off state, and the oil drain port of the pressure reducing valve 1 is connected to the oil drain port L of the oil drain oil circuit after passing through the relief valve 5 in the relief valve passage of the pressure reducing valve oil drain port pressure adjustment mechanism. At this time, the outlet pressure of the pressure reducing valve 1 is the set pressure of the pressure reducing valve 1 plus the set pressure of the relief valve 5 in the relief valve passage, and the plug chamber pressure of the upper and lower coil trolley cylinder 8 is switched to a high-pressure state. At this time, the controller controls the proportional reversing valve 2 to switch to a small opening state, and the flow rate is small, so the upper and lower coil trolley cylinder 8 rises at a low speed. At this time, the plug chamber high-pressure cylinder is in a low-speed state, and the upper and lower coil trolley rises steadily until the steel coil is safely and stably lifted to the set position;

[0042] Step three, the upper and lower coil unloading trolley 8 descends, and the rod chamber is in an oil supply state; when the steel coil has not fallen to the unloading position, the weight of the coil acts on the oil cylinder 8 of the upper and lower coil unloading trolley, which is equivalent to increasing the pressure in the rod chamber, and the back pressure of the plug chamber is also large. At this time, the second pressure setting point of the pressure relay 7 sends a No. 2 high pressure signal to the controller, and the controller controls the proportional reversing valve 2 to be in a small opening state, with a small flow rate, and the upper and lower coil unloading trolley descends at a low speed. When the steel coil falls to the unloading position, the back pressure of the plug chamber is reduced due to the lack of pressure from the weight of the coil, and the No. 2 high pressure signal of the pressure relay 7 disappears. At this time, the controller controls the proportional reversing valve 2 to switch to a large opening state, with a large flow rate, and the upper and lower coil unloading trolley quickly descends to the bottom position.

[0043] The utility model can realize automatic switching between high-speed rising of the low-pressure oil cylinder in the plug chamber and low-speed rising of the high-pressure oil cylinder in the plug chamber during the winding process according to different stages of the winding process, thereby saving the winding time, ensuring the stability of the steel coil during the winding process and avoiding damage to the reel due to excessive pressure.

[0044] The utility model realizes the automatic switching of the process of low-pressure oil cylinder and low speed of the oil cylinder rod chamber and the process of low-pressure oil cylinder and high speed of the oil cylinder rod chamber during the unloading process, thus saving the unloading time and improving the production rhythm.

[0045] The double hydraulically controlled one-way valves in the utility model can lock the oil cylinder of the coil loading and unloading trolley when needed; the superimposed relief valve can limit the pressure of the oil cylinder of the coil loading and unloading trolley, thereby ensuring the safe implementation of the coil loading or unloading process.

[0046] In the absence of conflicts, technicians in this field can combine the relevant technical features in the above examples according to actual conditions to achieve corresponding technical effects. The specific combinations are not described here one by one.

[0047] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0049] The above is only a preferred embodiment of the utility model. The utility model will not be limited to these embodiments shown in this article, but should conform to the widest range consistent with the principles and novel features disclosed in this article. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the utility model still fall within the scope of the technical solution of the utility model.

Claims

1. A coil loading and unloading trolley control system, characterized in that: The invention comprises a pressure reducing valve (1), a proportional reversing valve (2), a pressure relay (7), a winding trolley oil cylinder (8), a pressure regulating mechanism for a pressure reducing valve oil drain port, an oil supply oil circuit, an oil return oil circuit, an oil drain oil circuit and a controller; the pressure regulating mechanism for the pressure reducing valve oil drain port comprises an electromagnetic reversing valve passage and an overflow valve passage connected in parallel; an oil return port and an oil supply port are arranged on the winding trolley oil cylinder (8); the oil supply port is connected to an oil supply port P of the oil supply oil circuit through the pressure relay (7), the proportional reversing valve (2) and the pressure reducing valve (1) in sequence; the oil return port is connected to an oil return port T of the oil return oil circuit through the proportional reversing valve (2); the pressure reducing valve (1) is connected to an oil drain port L of the oil drain oil circuit through the electromagnetic reversing valve passage or the overflow valve passage in the pressure regulating mechanism for the pressure reducing valve oil drain port; and the controller is connected to the proportional reversing valve (2), the pressure relay (7) and the pressure regulating mechanism for the pressure reducing valve oil drain port by electrical signals.

2. A coil loading and unloading trolley control system as claimed in claim 1, characterized in that: It also includes a double hydraulically controlled one-way valve (3); the double hydraulically controlled one-way valve (3) is installed between the pressure relay (7) and the proportional reversing valve (2), and between the oil return port of the oil cylinder (8) of the loading and unloading trolley and the proportional reversing valve (2).

3. A coil loading and unloading trolley control system as claimed in claim 1 or 2, characterized in that: It also includes a stacked overflow valve (4); the stacked overflow valve (4) is connected between the pressure relay (7) and the proportional reversing valve (2), and is communicated with the oil return port T of the oil return circuit.

4. A coil loading and unloading trolley control system as claimed in claim 1, characterized in that: The electromagnetic reversing valve passage comprises a first oil circuit and an electromagnetic reversing valve (6), and the electromagnetic reversing valve (6) is connected to the first oil circuit.

5. A coil loading and unloading trolley control system as claimed in claim 1, characterized in that: The overflow valve passage comprises a second oil circuit and an overflow valve (5), and the overflow valve (5) is connected to the second oil circuit.

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