Mast-climbing work platform

Abstract

The application discloses a mast type aerial work platform, which comprises a chassis device, a lifting arm device, a platform body and a storage position detection device. The chassis device is surrounded to form a storage space. The lower end of a basic section arm of the lifting arm device is arranged in the storage space. Telescopic section arms of the lifting arm device are arranged on the outside of the basic section arm and can be lifted and lowered. The outermost telescopic section arm is provided with a trigger block on the lateral side. The platform body is arranged on the outermost telescopic section arm. The storage position detection device is arranged on the lateral side of the storage space and can be triggered under the abutting action of the lateral side of the trigger block. That is, the trigger force of the storage position detection device is arranged to be lateral. Compared with the downward trigger force, the probability of damage can be obviously reduced, and the service life is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-altitude machinery, and particularly relates to a mast type aerial work platform. BACKGROUND

[0002] The mast type aerial work platform is widely used in mechanical installation, equipment maintenance, building maintenance, and cargo storage indoors and outdoors of stations, wharfs, bridges, halls, and workshops. The mast type aerial work platform comprises a chassis, a liftable mast lifting arm, and a platform body. At present, in order to detect the movement of the mast lifting arm, a position detection switch is arranged at a storage position. If the position detection switch is triggered, it proves that the mast lifting arm has been lowered to the position. However, the existing position detection switch is triggered by a downward trigger force applied to the position detection switch by a trigger piece on the mast lifting arm. The trigger force is in the same direction as the gravity. The position detection switch is prone to damage due to excessive force. SUMMARY

[0003] In view of the above defects or deficiencies, the application provides a mast type aerial work platform, aiming to solve the technical problem that the position detection switch at the storage position is prone to damage due to the downward trigger force.

[0004] To achieve the above-mentioned purpose, the application provides a mast type aerial work platform, wherein the mast type aerial work platform comprises a chassis device, a lifting arm device, a platform body, and a storage position detection device. A storage space is formed by the chassis device. The lower end of the basic section arm of the lifting arm device is arranged in the storage space. The telescopic section arms of the lifting arm device are arranged outside the basic section arm and are liftable. The outermost telescopic section arm is provided with a trigger block. The platform body is arranged on the outermost telescopic section arm. The storage position detection device is arranged on the side of the storage space corresponding to the trigger block and can be triggered by the abutment of the trigger block.

[0005] In an embodiment of the application, the mast type aerial work platform further comprises a hydraulic drive system, a weighing device, a pressure detection device, an abnormal lifting alarm device, and a control device. The hydraulic drive system can drive the telescopic section arms to lift. The weighing device is used to detect the weight of the platform body. The pressure detection device is used to detect the oil pressure of the telescopic oil cylinder in the hydraulic drive system. The control device is in communication connection with the weighing device, the pressure detection device, and the abnormal lifting alarm device and is configured to:

[0006] In the case where it is determined that the platform body is in the lifting stop state, a first pressure value detected by the pressure detection device and a first weight value detected by the weighing device are obtained;

[0007] After a first preset time interval, a second pressure value detected by the pressure detection device and a second weight value detected by the weighing device are obtained;

[0008] In a case where the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold value and the deviation between the first weight value and the second weight value is less than the preset weight deviation threshold value, it is determined that the platform body is in an abnormal lifting state and the abnormal lifting alarm device is controlled to perform abnormal lifting prompting.

[0009] In an embodiment of the present application, the abnormal lifting state includes an abnormal descending state and an abnormal ascending state; in a case where the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold value and the deviation between the first weight value and the second weight value is less than the preset weight deviation threshold value, it is determined that the platform body is in an abnormal lifting state and the abnormal lifting alarm device is controlled to perform abnormal lifting prompting, including:

[0010] In a case where the first pressure value is greater than the second pressure value, the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold value, and the deviation between the first weight value and the second weight value is less than the preset weight deviation threshold value, it is determined that the platform body is in an abnormal descending state and the abnormal lifting alarm device is controlled to perform abnormal descending prompting; or

[0011] In a case where the first pressure value is less than the second pressure value, the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold value, and the deviation between the first weight value and the second weight value is less than the preset weight deviation threshold value, it is determined that the platform body is in an abnormal ascending state and the abnormal lifting alarm device is controlled to perform abnormal ascending prompting.

[0012] In an embodiment of the present application, it is determined that the platform body is in a lifting stop state, including:

[0013] In a case where the trigger signal of the collection position detection device is not received, it is determined that the platform body is in a lifting state;

[0014] In a case where the lifting signal instruction is not received for a second preset time length, it is determined that the platform body is in a lifting stop state.

[0015] In an embodiment of the present application, the control device is further configured to:

[0016] Obtain a third weight value detected by the weighing device;

[0017] Determine that the third weight value is less than a preset reverse force judgment weight threshold value, wherein the preset reverse force judgment weight threshold value is less than a predetermined empty load weight value of the platform body, and the empty load weight value is a weight value of the platform body in a case where the platform body is in an empty load lifting state and there is no interference object below the platform body;

[0018] Determine that there is an interference object below the platform body and limit the action of the mast type aerial work platform.

[0019] In an embodiment of the present application, the obtaining the third weight value detected by the weighing device further comprises:

[0020] In the case that the third weight value is greater than the empty weight value, determining a weight difference between the third weight value and the empty weight value;

[0021] Determining a ratio of the weight difference to a preset maximum bearing weight of the platform body to obtain a load rate;

[0022] In the case that the load rate is greater than a preset load rate threshold, determining that the platform body is overloaded and limiting the action of the mast type aerial work platform.

[0023] In an embodiment of the present application, the control device is further configured to:

[0024] In the case that the third weight value is greater than or equal to a preset reverse force judgment weight threshold, and / or the load rate is less than or equal to a preset load rate threshold, determining that the platform body is in a normal working state, and not limiting the action of the mast type aerial work platform.

[0025] In an embodiment of the present application, the storage space is formed by laterally enclosing the chassis device through the installation side plates, the storage position detection device comprises a swing lever type position detection switch, a main body part of the position detection switch is arranged on a side of the installation side plate away from the storage space, and an installation opening is formed in the installation side plate for a swing lever part of the position detection switch to extend to the storage space, and a trigger block is in abutment with the swing lever part.

[0026] In an embodiment of the present application, the installation opening is arranged on one side of the lifting arm device, the swing lever part comprises a swing lever mounting shaft arranged on the main body part and extending from the installation opening to the storage space, and a swing lever body rotatably sleeved on the swing lever mounting shaft, the trigger block is arranged on a side of the outermost telescopic arm towards the installation opening and is formed with an abutment surface in lateral abutment with the swing lever body, the abutment surface comprises a chamfered inclined surface and a vertical plane arranged in sequence from bottom to top, the chamfered inclined surface can press down the swing lever body and guide the swing lever body to the vertical plane, so that the vertical plane can laterally abut against the swing lever body in the case that the outermost telescopic arm is lowered to the storage position.

[0027] In an embodiment of the present application, the platform body and the outermost telescopic arm are one-to-one corresponding with a first connecting part and a second connecting part, the weighing device comprises a pin shaft weighing sensor in communication connection with the control device, the pin shaft weighing sensor is connected in series with the first connecting part and the second connecting part, and the outermost telescopic arm is further provided with a contact block, the contact block is located on the lower side of the second connecting part and is provided with a nylon contact layer on a side towards the platform body, and the nylon contact layer is used for lateral contact with a base frame of the platform body.

[0028] In an embodiment of the present application, the number of telescopic arms is at least two, and the at least two telescopic arms are nested on the outside of the basic arm in sequence, and each telescopic arm on the inside is provided with a first tensioning wheel and a second tensioning wheel at the upper end and the lower end, and the mast-type aerial work platform further comprises:

[0029] The traction device comprises an extension traction member and a retraction traction member, the extension traction member is arranged around the first tensioning wheel and connected to the adjacent two arms at both ends, and the retraction traction member is arranged around the second tensioning wheel and connected to the adjacent two arms at both ends.

[0030] The hydraulic drive system comprises a telescopic cylinder arranged on the basic arm and drivingly connected to the innermost telescopic arm, and a pressure stop valve connected to the rodless return oil circuit of the telescopic cylinder, and the pressure stop valve is set to be conductive when the oil pressure of the rodless return oil circuit reaches the preset load pressure.

[0031] In an embodiment of the present application, the rodless return oil circuit comprises a reversing valve rear oil circuit connecting the working oil port of the hydraulic reversing valve and the rodless cavity of the telescopic cylinder, the pressure stop valve is arranged on the reversing valve rear oil circuit, and the pressure stop valve comprises two valve groups arranged in parallel, one valve group comprises a first one-way valve conductive to the oil inlet direction of the telescopic cylinder, and the other valve group comprises a second one-way valve conductive to the oil outlet direction of the telescopic cylinder, and the second one-way valve is set to be conductive when the oil pressure of the reversing valve rear oil circuit reaches the preset load pressure.

[0032] In an embodiment of the present application, a lowering valve group is arranged between the rodless cavity of the telescopic cylinder and the hydraulic reversing valve, and the reversing valve rear oil circuit comprises a lowering valve front oil circuit connecting the hydraulic reversing valve and the lowering valve group.

[0033] The pressure stop valve is arranged on the lowering valve front oil circuit and is set as a two-way one-way valve with the first one-way valve and the second one-way valve, or the one-way valve on the lowering valve rear oil inlet oil circuit in the lowering valve group is set as the first one-way valve, and the second one-way valve is arranged on the lowering valve rear oil return oil circuit in the lowering valve group.

[0034] In an embodiment of the present application, the rodless return oil circuit comprises a first reversing valve front oil circuit connecting the oil tank and the oil return port of the hydraulic reversing valve, the pressure stop valve is arranged on the first reversing valve front oil circuit, and the pressure stop valve is set as a third one-way valve or a back pressure valve with adjustable opening pressure.

[0035] Through the above technical solutions, the mast-type aerial work platform provided by the present application has the following beneficial effects:

[0036] When the mast type aerial work platform is used, the storage position detection device is arranged laterally in the storage space, so that the storage position detection device is not exposed, and when the outermost telescopic arm is lowered to the storage space, the trigger block on the outermost telescopic arm is in lateral abutment with the storage position detection device, that is, the trigger force of the storage position detection device is lateral, compared with the downward trigger force, the probability of damage can be obviously reduced, and the service life is improved.

[0037] Other features and advantages of the present application will be described in detail in the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0038] The accompanying drawings are included to provide a further understanding of the embodiments of the application, and constitute a part of the specification, and are used to explain the embodiments of the application together with the following detailed description, but do not constitute a limitation on the embodiments of the application. For those skilled in the art, other drawings can be obtained from the structures shown in the drawings without creative labor. In the drawings:

[0039] Figure 1 is a control principle diagram of the mast type aerial work platform according to an embodiment of the application;

[0040] Figure 2 is a structural schematic diagram of the mast type aerial work platform in a storage state according to an embodiment of the application;

[0041] Figure 3 is Figure 2 is an enlarged structural schematic diagram of A in FIG. 8;

[0042] Figure 4 is a structural schematic diagram of the platform body according to an embodiment of the application;

[0043] Figure 5 is a partial structural schematic diagram of the lifting arm device according to an embodiment of the application;

[0044] Figure 6 is a partial structural schematic diagram of the mast type aerial work platform according to an embodiment of the application;

[0045] Figure 7 is Figure 6 is an enlarged structural schematic diagram of B in FIG. 10;

[0046] Figure 8 is another partial structural schematic diagram of the lifting arm device according to an embodiment of the application;

[0047] Figure 9is a structural schematic view of the storage position detection device and the trigger block according to an embodiment of the present application;

[0048] Figure 10 is a structural schematic view of the trigger block according to an embodiment of the present application;

[0049] Figure 11 is a structural schematic view of the aerial work platform in the lifting state according to an embodiment of the present application;

[0050] Figure 12 is a structural schematic view of the lifting arm device and the traction device according to an embodiment of the present application;

[0051] Figure 13 is a structural schematic view of the first connecting assembly on the basic arm according to an embodiment of the present application;

[0052] Figure 14 is a hydraulic principle schematic view of the hydraulic drive system according to the first embodiment of the present application;

[0053] Figure 15 is a hydraulic principle schematic view of the hydraulic drive system according to the second embodiment of the present application;

[0054] Figure 16 is a hydraulic principle schematic view of the hydraulic drive system according to the third embodiment of the present application;

[0055] Figure 17 is a control flow schematic view of the control device according to an embodiment of the present application.

[0056] Legend of reference signs:

[0057] 100 lifting arm device 110 basic arm

[0058] 120 telescopic arm 121 first tensioning wheel

[0059] 122 second tensioning wheel 130 trigger block

[0060] 131 abutting surface 132 chamfered slope

[0061] 133 vertical plane 140 second connecting portion

[0062] 141 yielding opening 142 second connecting hole

[0063] 150 contact block 200 traction device

[0064] 210 extending traction member 220 retracting traction member

[0065] 230 first connecting assembly 231 first connecting member

[0066] 232 second connecting member 233 fixing portion

[0067] 234 swing portion 240 second connecting assembly

[0068] 241 third connecting member 300 hydraulic drive system

[0069] 310 telescopic oil cylinder 320 pressure cut-off valve

[0070] 321 first one-way valve 322 second one-way valve

[0071] 323 third one-way valve 330 hydraulic reversing valve

[0072] 340 reversing valve rear oil passage 350 first reversing valve front oil passage

[0073] 360 oil supply assembly 370 lowering valve front oil passage

[0074] 380 lowering valve group 381 lowering valve body

[0075] 382 lowering valve rear oil inlet passage 383 lowering valve rear oil return passage

[0076] 384 damper 400 platform body

[0077] 410 first connecting portion 420 protective fence

[0078] 421 first horizontal rod 422 second horizontal rod

[0079] 430 base frame 500 weighing device

[0080] 600 storage position detection device 610 main body portion

[0081] 620 swing rod portion 621 first mounting plate portion

[0082] 622 connecting plate portion 623 second mounting plate portion

[0083] 624 wheel body 700 chassis device

[0084] 710 mounting side plate 711 mounting opening DETAILED DESCRIPTION

[0085] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0086] The mast type aerial work platform of the present application is described below with reference to the accompanying drawings.

[0087] As Figure 1 , Figure 2 , Figure 11 , Figure 6 and Figure 7 indicated, the application provides a mast type aerial work platform, wherein the mast type aerial work platform comprises:

[0088] a chassis device 700, a storage space is formed by surrounding the chassis device 700;

[0089] a lifting arm device 100, the lower end of the basic section arm 110 of the lifting arm device 100 is arranged in the storage space, the telescopic section arms 120 of the lifting arm device 100 are arranged in the outer side of the basic section arm 110 and can be lifted and lowered, and the circumferential side of the outermost telescopic section arm 120 is provided with a trigger block 130;

[0090] a platform body 400 arranged on the outermost telescopic section arm 120;

[0091] a storage position detection device 600 arranged corresponding to the trigger block 130 on the side of the storage space and can be triggered under the side abutting action of the trigger block 130.

[0092] When the mast type aerial work platform is used, since the storage space for arranging the lifting arm device 100 is formed by surrounding the chassis device 700, the storage position detection device 600 can be arranged on the side of the storage space, so as to avoid being exposed, and when the outermost telescopic section arm 120 is lowered to the storage space in place, the trigger block 130 on the outermost telescopic section arm 120 is in side abutting with the storage position detection device 600, that is, the triggering force of the storage position detection device 600 is arranged in the side direction, compared with the downward triggering force, the probability of damage phenomenon can be obviously reduced, so as to achieve the purpose of improving the service life.

[0093] Referring to Figure 1 , Figure 2 , Figure 11 , Figure 3 , Figure 12 and Figure 17 In an embodiment of the application, the mast type aerial work platform further comprises a hydraulic driving system 300, a weighing device 500, a pressure detection device, an abnormal lifting alarm device and a control device, the hydraulic driving system 300 can drive the telescopic section arms 120 to lift and lower, the weighing device 500 is used for detecting the weight of the platform body 400, the pressure detection device is used for detecting the oil pressure of the telescopic oil cylinder 310 in the hydraulic driving system 300, and the control device is in communication connection with the weighing device 500, the pressure detection device and the abnormal lifting alarm device and is configured to:

[0094] In step S102, when it is determined that the platform body 400 is in the lifting stop state, a first pressure value detected by the pressure detection device and a first weight value detected by the weighing device 500 are acquired;

[0095] In step S104, after a first preset time interval, a second pressure value detected by the pressure detection device and a second weight value detected by the weighing device 500 are acquired;

[0096] In step S106, when a deviation between the first pressure value and the second pressure value is greater than a preset pressure deviation threshold value, and a deviation between the first weight value and the second weight value is less than a preset weight deviation threshold value, it is determined that the platform body 400 is in an abnormal lifting state, and an abnormal lifting alarm device is controlled to perform abnormal lifting prompting.

[0097] It can be understood that the hydraulic driving system 300 is used to drive the lifting arm device 100 to drive the platform body 400 to realize lifting action. The first preset time interval is a pre-set time length, for example, 2 seconds or 5 seconds, etc. The first pressure value and the first weight value can be detection values at a starting time point of the first preset time interval, and the second pressure value and the second weight value can be detection values at an ending time point of the first preset time interval. The preset pressure deviation threshold value is a pre-set pressure deviation threshold value of the hydraulic driving system 300. The preset weight deviation threshold value is a pre-set weight deviation threshold value of the platform body 400. The abnormal lifting alarm device can be a buzzer, a sound-light alarm, a three-color LED alarm, or a device for performing screen display prompting alarm. It needs to be particularly pointed out that the communication connection mentioned in the present application can be wire connection or wireless connection.

[0098] Specifically, the control device obtains the first pressure value detected by the pressure detection device and the first weight value detected by the weighing device 500 when determining that the platform body 400 is in the lifting stop state. After a first preset time interval, the control device continues to obtain the second pressure value detected by the pressure detection device and the second weight value detected by the weighing device 500. Then, the control device can compare the first pressure value with the second pressure value, compare the first weight value with the second weight value, and determine that the platform body 400 is in an abnormal lifting state when the deviation between the first pressure value and the second pressure value is greater than a preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than a preset weight deviation threshold. Understandably, the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold, which means that the pressure of the hydraulic driving system 300 changes significantly after the platform body 400 stops lifting. The deviation between the first weight value and the second weight value is less than the preset weight deviation threshold, which means that the weight of the platform body 400 does not change significantly after the platform body 400 stops lifting. In combination, the pressure of the hydraulic driving system 300 changes, but the weight of the platform body 400 does not change significantly, thereby excluding the influence factor that the pressure of the hydraulic driving system 300 changes due to the change of the load of the platform body 400. It can be determined that the platform body 400 has a lifting abnormality, i.e., the platform body 400 is in an abnormal lifting state.

[0099] In the above technical solution, by comparing the pressure value of the hydraulic driving system 300 and the weight value of the platform body 400 at different time points after the platform body 400 stops lifting, and combining the pressure value change amount and the weight value change amount, it is determined whether the platform body 400 is in an abnormal lifting state. When the pressure value change amount is greater than the preset pressure deviation threshold and the weight value change amount is less than the preset weight deviation threshold, it is determined that the platform body 400 is in an abnormal lifting state. This can realize rapid and accurate judgment of the abnormal result of the aerial work platform, thereby reducing the influence of abnormal conditions on construction work and further improving the construction safety of the aerial work platform.

[0100] In an embodiment of the present application, the abnormal lifting state includes an abnormal descending state and an abnormal ascending state. When the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than the preset weight deviation threshold, it is determined that the platform body 400 is in an abnormal lifting state and the abnormal lifting alarm device is controlled to perform abnormal lifting prompting.

[0101] In a case where the first pressure value is greater than the second pressure value, the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than the preset weight deviation threshold, it is determined that the platform body 400 is in an abnormal descending state, and the abnormal lifting alarm device is controlled to give an abnormal descending prompt.

[0102] In a case where the first pressure value is less than the second pressure value, the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than the preset weight deviation threshold, it is determined that the platform body 400 is in an abnormal ascending state, and the abnormal lifting alarm device is controlled to give an abnormal ascending prompt.

[0103] It can be understood that, generally, the pressure of the hydraulic driving system 300 tends to decrease in the descending process of the platform body 400, and tends to increase in the ascending process of the platform body 400. Therefore, if the first pressure value is greater than the second pressure value, the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than the preset weight deviation threshold, the control device can determine that the platform body 400 is in an abnormal descending state; if the first pressure value is less than the second pressure value, the deviation between the first pressure value and the second pressure value is greater than the preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than the preset weight deviation threshold, the control device can determine that the platform body 400 is in an abnormal ascending state.

[0104] In an embodiment of the present application, determining that the platform body 400 is in a lifting stop state comprises:

[0105] In a case where the trigger signal of the storage position detection device 600 is not received, it is determined that the platform body 400 is in a lifting state.

[0106] In a case where the lifting signal instruction is not received for the second preset time length, it is determined that the platform body 400 is in a lifting stop state.

[0107] It can be understood that, after the control device receives the trigger signal of the storage position detection device 600, it can be determined that the platform body 400 is in a storage position. Conversely, when the platform body 400 is lifted from the storage position, the outermost telescopic arm 120 is driven to ascend and leave the trigger area of the storage position detection device 600, so that the position detection device enters an untriggered state. At this time, the control device does not receive the trigger signal of the storage position detection device 600, so it can be determined that the platform body 400 enters a lifting state.

[0108] Specifically, when the platform body 400 is in the storage position, the storage position detection device 600 can trigger a signal, and if the control device does not receive the trigger signal of the storage position detection device 600, it can be determined that the platform body 400 is in the lifting state. That is, the control device can determine whether the platform body 400 is in the lifting state or the storage state through the storage position detection device 600.

[0109] It should be particularly pointed out that when the platform body 400 is in the storage position, even if there is an abnormal lifting, there is no safety risk to the operator on the platform, so only when the platform body 400 is in the non-storage position, the judgment of the abnormal lifting of the platform body 400 is needed, which avoids unnecessary waste of resources and improves the operation efficiency.

[0110] In addition, the platform operating device can be used as a device for operating the lifting of the platform body 400. The operator inputs the lifting signal instruction to the platform operating device to realize the operation of the platform body 400. The second preset time length is a pre-set waiting time, for example, 3 seconds or 5 seconds.

[0111] Specifically, when the platform body 400 is in the lifting state, if the control device does not receive the lifting signal instruction sent by the platform operating device for the second preset time length, it can be determined that the platform body 400 stops the lifting action and enters the lifting stop state.

[0112] In one example, the pressure detection device can be a pressure sensor arranged on the hydraulic valve block of the hydraulic driving system 300 located in the telescopic oil cylinder 310. When the platform body 400 is lifted to a certain position and stops, the pressure of the hydraulic driving system 300 will be locked to a fixed value under the condition that the load on the platform body 400 remains unchanged. In the case of the platform body 400 being stationary, if the telescopic oil cylinder 310 has internal leakage or the valve core is stuck or the drop valve signal is abnormally output, etc., it may cause the platform body 400 to abnormally descend.

[0113] Taking the abnormal descent of the platform body 400 as an example, the control method of the abnormal descent of the platform body 400 can specifically include the following steps:

[0114] After the whole machine is powered on, the operation platform control box (i.e. the platform operating device) makes the platform body 400 in a lifting state. The control device (i.e. the ECU) of the whole machine records the pressure signal value P1 and the platform load signal value G1 at the time when the platform body 400 stops the lifting action for 2s, and compares the pressure value and the platform load value after 2s. The pressure value and the platform load value continuously received after 2s are set as P2 and G2 respectively. When it is detected that the pressure value decreases by more than ΔP and the platform body load value does not decrease by more than ΔG, the control device of the whole machine outputs a signal to control an alarm. After the alarm, the control device of the whole machine can limit other operations, and only can be lowered, or can limit all actions, i.e. the alarm condition can be: P1-P2>ΔP and G1-G2<ΔG.

[0115] wherein ΔP and ΔG are threshold values preset in the control device of the whole machine in advance, and the two threshold values are obtained according to actual working condition tests of the whole machine and can be adjusted in the control device of the whole machine. The set threshold values are reasonable, which can effectively detect the abnormal descent of the platform body 400 and prevent false alarms.

[0116] When the platform body 400 is controlled to perform a lifting or lowering action again, or after being powered on again, the above data is automatically cleared, and the pressure signal value P1 and the platform load signal value G1 at the time of stopping are collected again, and the above control logic is executed again.

[0117] The technical scheme provided by the above embodiment can automatically detect whether the platform body 400 has an abnormal descent under different working conditions, whether before the device is used or during use, automatic detection can be realized, and the operator is reminded to timely repair the abnormality, thereby reducing the safety risk.

[0118] In an embodiment of the present application, the control device is further configured to:

[0119] acquire a third weight value detected by the weighing device 500;

[0120] determine that the third weight value is less than a preset reverse force judgment weight threshold value, wherein the preset reverse force judgment weight threshold value is less than a predetermined empty load weight value of the platform body 400, and the empty load weight value is a weight value of the platform body 400 in an empty load lifting state and without an interference object below the platform body 400;

[0121] determine that there is an interference object below the platform body 400 and limit the action of the mast type aerial work platform.

[0122] It can be understood that the third weight value is the weight value of the platform body 400 detected by the weighing device 500 in any scenario. The preset reverse force judgment weight threshold is a weight threshold for judging whether the platform body 400 is subjected to an upward reverse force (i.e., a support force) opposite to the direction of gravity, that is, if the weight detection value of the platform body 400 is less than the preset reverse force judgment weight threshold, it can be determined that the platform body 400 is subjected to an upward reverse force opposite to the direction of gravity, which can indicate that there is an interference object below the platform body 400, and the interference object generates an upward support force on the platform body 400. Understandably, the preset reverse force judgment weight threshold is less than the predetermined no-load weight value of the platform body 400. The no-load weight value is the weight value of the platform body 400 in the no-load lifting state and there is no interference object below the platform body 400. The no-load lifting state means that there is no person or object on the platform body 400, and the platform body 400 is in a lifting state, i.e., a non-stored state. The no-load weight value can be determined in advance. The interference object can include a person or object that may interfere with the normal operation of the aerial work platform, for example, it can be a wooden block.

[0123] Specifically, when the platform body 400 is in a rising state, a descending state or a stationary state, the control device can communicate with the weighing device 500, so that the third weight value detected by the weighing device 500 can be obtained in real time, and the third weight value is compared with the preset reverse force judgment weight threshold. When it is determined that the third weight value is less than the preset reverse force judgment weight threshold, the control device can determine that there is an interference object below the platform body 400 at this time.

[0124] In the above technical solution, by obtaining the weight detection value of the platform body 400 detected by the weighing device 500, when it is determined that the weight detection value is less than the preset reverse force judgment weight threshold, it can be determined that there is an interference object below the platform body 400. Without the need for additional interference object detection equipment, only by detecting the weight information detected by the weighing device 500 for detecting the weight of the platform body 400, it can be judged whether there is an interference object below the platform body 400, which reduces the hardware cost, and limits the action of the mast type aerial work platform when it is determined that there is an interference object, thereby improving the construction safety of the aerial work platform.

[0125] In an embodiment of the present application, after obtaining the third weight value detected by the weighing device 500, it further includes:

[0126] In the case where the third weight value is greater than the no-load weight value, determining a weight difference value between the third weight value and the no-load weight value;

[0127] Determining a ratio of the weight difference value to a preset maximum load weight of the platform body 400 to obtain a load rate;

[0128] In a case where the load rate is greater than a preset load rate threshold, it is determined that the platform body 400 is overloaded and the action of the mast-type aerial work platform is limited.

[0129] It can be understood that the preset maximum load capacity is a maximum load that the platform body 400 can bear in advance. The load rate is a ratio of the weight difference to the preset maximum load capacity. The weight difference is a difference between the third weight value and the empty weight value, that is, the weight of the person and / or object carried on the platform body 400. The preset load rate threshold is a preset load rate threshold for determining that the platform body 400 is overloaded, for example, 85% or 90%. If the load rate is greater than the preset load rate threshold, it can be determined that the platform body 400 is overloaded.

[0130] Specifically, the control device can compare the third weight value of the platform body 400 with the predetermined empty weight value of the platform body 400. When it is determined that the third weight value is greater than the empty weight value, the control device can determine the weight difference between the third weight value and the empty weight value, and determine the ratio of the weight difference to the preset maximum load capacity of the platform body 400 to obtain the load rate of the platform body 400 at this time. Further, the load rate of the platform body 400 is compared with the preset load rate threshold. When it is determined that the load rate is greater than the preset load rate threshold, the control device can determine that the platform body 400 is overloaded.

[0131] In the above technical solution, when the third weight value is greater than the empty weight value, the load rate of the platform body 400 is determined, and when the load rate is greater than the preset load rate threshold, it is determined that the platform body 400 is overloaded, which can realize accurate and rapid determination of the overload of the platform body 400, further improve the construction safety of the aerial work platform, and prolong the service life of the aerial work platform.

[0132] In an embodiment of the present application, the control device is further configured to:

[0133] In a case where the third weight value is greater than or equal to the preset reverse force judgment weight threshold, and / or the load rate is less than or equal to the preset load rate threshold, it is determined that the platform body 400 is in a normal working state, and the action of the mast-type aerial work platform is not limited.

[0134] It can be understood that the normal working state of the platform body 400 can include a working state in which there is no interference below the platform body 400 and / or a working state in which the platform body 400 is not overloaded.

[0135] Specifically, if the weight detection value of the platform body 400 is greater than or equal to the preset reverse force judgment weight threshold value, it indicates that there is no interference object below the platform body 400, and if the load rate of the platform body 400 is less than or equal to the preset load rate threshold value, it indicates that the platform body 400 is not overloaded. In at least one of the above two cases, the control device can determine that the platform body 400 is in a normal working state, and the control device can not limit the action of the aerial work platform at this time.

[0136] In the above technical solution, when the weight detection value of the platform body 400 is greater than or equal to the preset reverse force judgment weight threshold value, and / or the load rate of the platform body 400 is less than or equal to the preset load rate threshold value, it indicates that the platform body 400 is in a normal working state, and the control device does not limit the action of the aerial work platform, which can further improve the operation efficiency of the aerial work platform.

[0137] In an embodiment of the present application, the determination of the empty weight value can include: determining that the weighing device 500 is in a normal working state; and calibrating the weighing device 500 to obtain the empty weight value of the platform body 400 detected by the weighing device 500 in the case that the platform body 400 is in an empty load lifting state and there is no interference object below the platform body 400.

[0138] In an embodiment of the present application, determining that the weighing device 500 is in a normal working state can include: determining that the weighing device 500 is in a normal working state in the case that data sent by the weighing device 500 is received within a preset time period and / or at intervals of a preset time length; and / or determining that the weighing device 500 is in a normal working state in the case that no fault message sent by the weighing device 500 is received.

[0139] It can be understood that the preset time period is a pre-set time period, and the preset time length is a pre-set time length. The fault message is content information indicating that the weighing device 500 has failed.

[0140] In an embodiment of the present application, the control device is further configured to: determine that the weighing device 500 has failed and limit the action of the aerial work platform in the case that data sent by the weighing device 500 is not received within a preset time period and / or at intervals of a preset time length; and / or determine that the weighing device 500 has failed and limit the action of the aerial work platform in the case that a fault message sent by the weighing device 500 is received, thereby ensuring the safety of man-machine.

[0141] In an embodiment of the present application, the weighing device 500 can be at least two, and determining that the weighing device 500 is in a normal working state can include: acquiring detection data of each weighing device 500; and in a case where differences between the detection data of each weighing device 500 are all within a preset error range, determining that the weighing device 500 is in a normal working state.

[0142] In an embodiment of the present application, the control device is further configured to: in a case where the difference between the detection data of any two weighing devices 500 is not within the preset error range, determine that the weighing device 500 is malfunctioning, and limit the aerial work platform from moving.

[0143] In a specific embodiment, the weighing device 500 is taken as a pin shaft load cell for example, the pin shaft load cell can be installed at a connection between the platform body 400 and the telescopic arm 120, the weight of the load of the platform body 400 is detected through a change of a strain gauge inside the pin shaft load cell, the signal is processed by the acquisition module and then transmitted to the control device of the whole machine, the control device formulates a safety logic according to a safety regulation of the aerial work product, and the safety of the operator and the equipment is protected through sound and light alarm and movement limitation.

[0144] In the above embodiment, the number of pin shaft load cells can be two, and the control device can perform the following steps.

[0145] Step S201, start.

[0146] Step S202, determine whether the pin shaft load cell is normal, if yes, go to step S203, otherwise go to step S204.

[0147] Step S203, determine whether the weighing calibration of the pin shaft load cell is completed, if yes, go to step S205, otherwise go to step S206.

[0148] Step S204, report a pin shaft load cell failure, perform sound and light alarm, and limit the movement of the aerial work platform.

[0149] Step S205, acquire the weight detection values of the two pin shaft load cells, and step S205 is followed by step S207 and step S208.

[0150] Step S206, report that the weighing calibration is not completed, perform sound and light alarm, and do not limit the movement of the aerial work platform.

[0151] Step S207, determine whether the load rate of the platform body is greater than a set value (i.e., a preset load rate threshold), if yes, go to step S209, otherwise go back to step S202.

[0152] Step S208, judge whether the weight detection values of the two pin shaft load sensors are less than the reverse force alarm threshold (i.e. the preset reverse force judgment weight threshold), if yes, go to step S210, otherwise return to step S202.

[0153] Step S209, report that the platform body is overloaded, and perform sound and light alarm to limit the action of the aerial work platform.

[0154] Step S210, report that the platform body is under abnormal stress, and perform sound and light alarm to limit the action of the aerial work platform.

[0155] Regarding step S202, specifically, in order to ensure normal operation of the equipment and protect the safety of man and machine, the platform load (i.e. weight) must be detected in real time. The pin shaft load sensor can use a preset communication protocol to communicate with the control device of the whole machine. When the control device of the whole machine does not receive data or receives a predetermined fault message within a set time, it reports that the corresponding pin shaft load sensor has a communication fault or a hardware fault. In order to ensure the safety of man and machine, the equipment is limited to act at this time.

[0156] In order to protect the safety of personnel and equipment, the key component pin shaft load sensor needs to meet the redundancy detection requirement. The pin shaft load sensor internally cross-arranges two strain gauges to simultaneously detect the force transmitted by the platform, and sends the signal to the control device of the whole machine through different fields to realize double-channel redundancy design. The control device of the whole machine internally judges the difference between the detection values of the two fields. If the difference exceeds the set value, it reports that the double-channel check of the pin shaft load sensor is wrong. At this time, it is also considered that the pin shaft load sensor is malfunctioning, and the equipment is limited to act.

[0157] Regarding step S203, specifically, when the platform body 400 is empty and in the lifting state and there is no obstacle or interference below, the sum of the weight values detected by the two pin shaft load sensors at this time is taken as the reference value of the empty load of the platform body, i.e. the empty load weight value is obtained. Further, in the program of the control device of the whole machine of the aerial work platform, the full load weight value can be preset, i.e. the maximum bearing load is preset.

[0158] Regarding step S207, specifically, the control device of the whole machine can obtain the platform load in real time. When the platform body increases the load, the calculation formula of the load rate at this time can be:

[0159]

[0160] Wherein, G1 and G2 are the weight detection values of the two pin shaft load sensors, G0 is the empty load weight value of the platform body, G maxThis is the set value for a fully loaded platform, i.e., the preset maximum load capacity. The machine's control device can calculate the load factor in real time. When the load factor exceeds the set percentage, the control device will issue an audible and visual alarm signal and restrict equipment operation.

[0161] Regarding step S207, specifically, in order to prevent the platform body 400 from squeezing the operator or obstacles when it descends, causing personal injury or equipment damage. The control device of the entire machine performs real-time detection of the platform body load. When the pin shaft weighing sensor is in a normal state, the minimum weight detection value should be the weight value of the platform body 400 when it is in an unloaded state, that is, the weight value of the platform body 400 itself. If the weight value detected by the pin shaft weighing sensor is less than the reverse force alarm threshold, it is considered that the platform body 400 is subjected to the effect of a reverse force, such as there is a wooden block supporting it from below. At this time, the platform force abnormality can be reported to restrict the platform from continuing to descend. It is understandable that the reverse force alarm threshold should be as small as possible from the weight value of the platform body 400 itself, because when the platform body 400 is lifted and lowered, it will produce impact due to inertia, causing the weight value detected by the pin shaft weighing sensor to fluctuate and may be smaller than the actual value. Therefore, in order to prevent false alarms, the reverse force alarm threshold should be as small as possible from the weight value of the platform body 400 itself.

[0162] like Figure 1 、 Figure 6 to Figure 10 In one embodiment of the present application, a storage space is formed by laterally enclosing the chassis device 700 via a mounting side panel 710. The storage position detection device 600 includes a rocker-type position detection switch. The main body 610 of the position detection switch is located on the side of the mounting side panel 710 facing away from the storage space. The mounting side panel 710 also includes an installation opening 711 for the rocker portion 620 of the position detection switch to extend into the storage space. The trigger block 130 can abut against the rocker portion 620. By locating the main body 610 of the position detection switch on the side of the mounting side panel 710 facing away from the storage space, a certain degree of protection is provided while allowing the position detection switch to be installed and removed from the outside of the storage space. Compared to a narrow storage space, installation and removal from the outside is significantly more convenient. Specifically, the installation opening 711 is located at the upper end of the mounting side panel 710.

[0163] In one embodiment of the present application, the mounting opening 711 is set on a side of the lifting arm device 100, and in order to enable the rocker arm portion 620 of the position detection switch to extend from the mounting opening 711 to the storage space, the main body 610 of the position detection switch should be set at a position corresponding to the mounting opening 711, that is, the main body 610 is also set to be set on a side of the lifting arm device 100, which can facilitate the subsequent lateral abutment arrangement between the rocker arm portion 620 and the trigger block 130. The rocker arm portion 620 includes a rocker arm mounting shaft provided on the main body 610 and extending from the mounting opening 711 to the storage space, and a rocker arm body rotatably sleeved on the rocker arm mounting shaft. The trigger block 130 is provided on the side of the outermost telescopic arm 120 facing the mounting opening 711, and is formed. The abutment surface 131, which laterally abuts the rocker arm body, is specifically configured to face a side surface of the rocker arm body. The abutment surface 131 includes a chamfered surface 132 and a vertical plane 133, arranged sequentially from bottom to top. During the retraction and descent of the telescopic arm 120, the chamfered surface 132 first presses down on the rocker arm body, causing it to swing downward at a certain angle to an inclined position. As the telescopic arm 120 continues to retract and descend, guided by the chamfered surface 132, the vertical plane 133 switches to continue abutting against the wheel 624 on the rocker arm body. Furthermore, due to the tilted configuration of the rocker arm body, the vertical plane 133 continues to exert pressure on the rocker arm body, allowing it to laterally abut the rocker arm body when the telescopic arm 120 is lowered into place. The addition of the chamfered surface 132 facilitates the smooth guidance of the rocker arm body until it abuts laterally against the rocker arm body.

[0164] Furthermore, the rocker arm body includes a first mounting plate portion 621, a connecting plate portion 622 and a second mounting plate portion 623 which are arranged in sequence from the rocker arm mounting axis toward the abutment surface 131, and the first mounting plate portion 621 is rotatably mounted on the rocker arm mounting axis, the connecting plate portion 622 is bent from the first mounting plate portion 621 toward a direction away from the main body portion 610, and the second mounting plate portion 623 is bent from one end of the connecting plate portion 622 away from the first mounting plate portion 621 toward a side away from the first mounting plate portion 621, and a wheel body 624 is provided on the second mounting plate portion 623.

[0165] like Figure 2 and Figure 3As shown, in an embodiment of the present application, the platform body 400 and the outermost telescopic arm 120 are provided with a first connecting part 410 and a second connecting part 140 in one-to-one correspondence, and the weighing device 500 includes a pin shaft load cell in communication connection with the control device, and the pin shaft load cell is connected in series with the first connecting part 410 and the second connecting part 140. That is, by connecting the first connecting part 410 and the second connecting part 140 in series through the pin shaft load cell, the connection of the platform body 400 and the lifting arm device 100 is realized, and the load weight on the platform body 400 is detected, achieving two goals at once. Specifically, the number of the first connecting part 410, the second connecting part 140 and the pin shaft load cell is two, the two second connecting parts 140 are sequentially and spaced apart along the width direction of the outermost telescopic arm 120, the two first connecting parts 410 are respectively provided on one side of the platform body 400 in one-to-one correspondence with the two second connecting parts 140, and the two pin shaft load cells are connected in series with the corresponding first connecting part 410 and second connecting part 140.

[0166] Referring to Figure 2 to Figure 4 In an embodiment of the present application, the protective fence 420 of the platform body 400 is provided with a first cross bar 421 and a second cross bar 422 near one side of the lifting arm device 100, the first cross bar 421 and the second cross bar 422 are sequentially and spaced apart horizontally from bottom to top, the first connecting part 410 includes two first connecting ear plates which are vertically arranged and spaced apart between the first cross bar 421 and the second cross bar 422, the lower ends of the two first connecting ear plates are respectively connected with the first cross bar 421, and the upper ends thereof are respectively connected with the second cross bar 422, the second connecting part 140 includes a second connecting ear plate which is horizontally arranged and extended from the lifting arm device 100, and the second connecting ear plate can be extended into the two first connecting ear plates and connected in series through the pin shaft load cell. The first connecting part 410 is provided with two first connecting ear plates, and the upper and lower ends of the two first connecting ear plates are provided with cross bars, so that the connection between the first connecting part 410 and the second connecting part 140 is more stable, and the two cross bars can also become a stop position for the second connecting ear plate during the process of extending into the two first connecting ear plates and adjusting the hole position. Specifically, two nylon clamping pads are further sleeved on the pin shaft load cell, and the two nylon clamping pads are arranged in the gap between the two first connecting ear plates and the second connecting ear plate.

[0167] Referring to Figure 2 to Figure 5In an embodiment of the present application, the first connecting lug and the second connecting lug are respectively and one-to-one provided with a first connecting hole and a second connecting hole 142, the pin shaft load cell is arranged in the first connecting hole and the second connecting hole 142, and the upper end or the lower end of the second connecting lug is provided with a clearance opening 141. The clearance opening 141 is used to accommodate the corresponding cross bar when the first connecting hole and the second connecting hole 142 are aligned. The clearance opening 141 facilitates the alignment of the first connecting hole and the second connecting hole 142. Specifically, in the process of aligning the first connecting hole and the second connecting hole 142, the clearance opening 141 is first aligned with the corresponding cross bar, and then the alignment is moved so that the corresponding cross bar enters the clearance opening 141, and finally the fine adjustment is performed to realize the alignment of the first connecting hole and the second connecting hole 142. It should be particularly pointed out that after the platform body 400 is connected with the lifting arm device 100, the clearance opening 141 does not exert a supporting force on the platform body 400, that is, a gap is left between the clearance opening 141 and the corresponding cross bar. Preferably, the clearance opening 141 is provided at the upper end of the second connecting lug and can accommodate the second cross bar 422, and the second connecting hole 142 is located directly below the clearance opening 141, and the first connecting hole is located directly below the second cross bar 422.

[0168] In an embodiment of the present application, the lifting arm device 100 is further provided with a contact block 150. Specifically, the contact block 150 is arranged on the outermost telescopic arm, and the contact block 150 is located on the lower side of the second connecting portion 140 and is provided with a nylon contact layer on the side facing the platform body 400. The nylon contact layer is used to laterally contact the base frame 430 of the platform body 400. The addition of the contact block 150 can avoid friction between the base frame 430 of the platform body 400 and the lifting arm device 100, and the addition of the nylon contact layer makes the contact block 150 and the base frame 430 in smooth contact, so that the contact block 150 does not exert a supporting action on the platform body 400, thereby ensuring the accuracy of the weighing device 500. Specifically, the number of contact blocks 150 is two, and the two contact blocks 150 are arranged in sequence and spaced apart along the width direction on the side of the lifting arm device 100 facing the platform body 400.

[0169] As shown in Figure 2 , Figure 11 , Figure 12 , Figure 14 to Figure 16 In an embodiment of the present application, the number of telescopic arms 120 is at least two, and the at least two telescopic arms 120 are nested in sequence on the outer side of the basic arm 110. The telescopic arms 120 located on the inner side are each provided with a first tensioning wheel 121 and a second tensioning wheel 122 at the upper end and the lower end, and the mast-type aerial work platform further comprises:

[0170] The traction device 200 comprises an extension traction member 210 and a retraction traction member 220, the extension traction member 210 is arranged around the first tensioning wheel 121 and connected to the adjacent two side joint arms at both ends, and the retraction traction member 220 is arranged around the second tensioning wheel 122 and connected to the adjacent two side joint arms at both ends.

[0171] The hydraulic drive system 300 comprises a telescopic oil cylinder 310 arranged on the basic joint arm 110 and drivingly connected to the innermost telescopic joint arm 120, and a pressure stop valve 320 connected to the rodless return oil circuit of the telescopic oil cylinder 310, the pressure stop valve 320 is set to be turned on when the oil pressure in the rodless return oil circuit reaches the preset load pressure.

[0172] In the above technical solution, since the telescopic joint arms 120 located on the inner side are provided with the first tensioning wheel 121 and the second tensioning wheel 122 at the upper and lower ends, the traction device 200 not only comprises the extension traction member 210 arranged around the first tensioning wheel 121, but also comprises the retraction traction member 220 arranged around the second tensioning wheel 122, so that when the telescopic oil cylinder 310 drives the innermost telescopic joint arm 120 to extend, the first tensioning wheel 121 can drive the other telescopic joint arms 120 to extend synchronously due to the action of the extension traction member 210, and when the telescopic oil cylinder 310 drives the innermost telescopic joint arm 120 to retract, the second tensioning wheel 122 can drive the other telescopic joint arms 120 to retract synchronously due to the action of the retraction traction member 220, if one telescopic joint arm 120 is stuck during the descending process of the platform body 400, all the telescopic joint arms 120 will stop synchronously due to the pulling action of the retraction traction member 220, and will not descend any more, so that the phenomenon of traction member relaxation can be avoided, and the pressure stop valve 320 is additionally arranged in the rodless return oil circuit of the telescopic oil cylinder 310, the pressure stop valve 320 is turned on only when the oil pressure in the rodless return oil circuit reaches the preset load pressure, when all the telescopic joint arms 120 are stuck synchronously, the oil pressure in the rodless return oil circuit will decrease, so that the pressure stop valve 320 is not turned on in response, and the rodless cavity of the telescopic oil cylinder 310 does not run out of oil and maintains a certain back pressure, after the stuck is eliminated, the phenomenon of rapid descending due to the emptying of oil in the rodless cavity can also be avoided, and the safety performance is improved.

[0173] Specifically, the number of telescopic joint arms 120 can be at least two, and the telescopic joint arms 120 located on the inner side refer to all the telescopic joint arms 120 between the basic joint arm 110 and the outermost telescopic joint arm 120. It should be particularly noted that the adjacent two side joint arms refer to the inner and outer side joint arms of the telescopic joint arm 120 corresponding to the currently installed tensioning wheel.

[0174] The present application will be described with four telescopic arms 120 as an example, that is, the lifting arm device 100 has five arms in total, from inside to outside, they are: the basic arm 110, the first telescopic arm, the second telescopic arm, the third telescopic arm and the fourth telescopic arm, the number of telescopic arms 120 located on the inside is three, that is, the first telescopic arm, the second telescopic arm and the third telescopic arm, and the telescopic oil cylinder 310 is drivingly connected with the first telescopic arm. In order to realize the synchronous telescoping of the remaining telescopic arms 120 following the first telescopic arm, the first telescopic arm, the second telescopic arm and the third telescopic arm are each provided with a first tension pulley 121 and a second tension pulley 122 at the upper and lower ends. The two ends of the extension traction member 210 wound on the first tension pulley 121 of the first telescopic arm are both arranged downward and connected with the basic arm 110 and the second telescopic arm respectively, the two ends of the extension traction member 210 wound on the first tension pulley 121 of the second telescopic arm are both arranged downward and connected with the first telescopic arm and the third telescopic arm respectively, the two ends of the extension traction member 210 wound on the first tension pulley 121 of the third telescopic arm are both arranged downward and connected with the second telescopic arm and the fourth telescopic arm respectively, the two ends of the extension traction member 210 wound on the first tension pulley 121 of the fourth telescopic arm are both arranged downward and connected with the third telescopic arm and the fifth telescopic arm 120 respectively, so as to realize the synchronous extension of the second telescopic arm, the third telescopic arm and the fourth telescopic arm following the first telescopic arm; the two ends of the retraction traction member 220 wound on the second tension pulley 122 of the first telescopic arm are both arranged upward and connected with the basic arm 110 and the second telescopic arm respectively, the two ends of the retraction traction member 220 wound on the second tension pulley 122 of the second telescopic arm are both arranged upward and connected with the first telescopic arm and the third telescopic arm respectively, the two ends of the retraction traction member 220 wound on the second tension pulley 122 of the third telescopic arm are both arranged upward and connected with the second telescopic arm and the fourth telescopic arm respectively, the two ends of the retraction traction member 220 wound on the second tension pulley 122 of the fourth telescopic arm are both arranged upward and connected with the third telescopic arm and the fifth telescopic arm 120 respectively, so as to realize the synchronous retraction of the second telescopic arm, the third telescopic arm and the fourth telescopic arm following the first telescopic arm.

[0175] Referring to Figure 14 and Figure 15In the first and second embodiments of the present application, the rodless cavity oil return circuit includes a valve post oil circuit 340 which communicates the working oil port of the hydraulic reversing valve 330 and the rodless cavity of the telescopic cylinder 310, and the pressure cut-off valve 320 is arranged on the valve post oil circuit 340, i.e. the pressure cut-off valve 320 can be arranged on the oil circuit between the telescopic cylinder 310 and the working oil port of the hydraulic reversing valve 330, and the pressure cut-off valve 320 includes two valve groups arranged in parallel, one of which includes a first one-way valve 321 which is open in the oil inlet direction of the telescopic cylinder 310, and the other of which includes a second one-way valve 322 which is open in the oil outlet direction of the telescopic cylinder 310, and the second one-way valve 322 is set to be open when the oil pressure of the valve post oil circuit 340 reaches a preset load pressure. Arranging the pressure cut-off valve 320 on the valve post oil circuit 340 makes the position of the pressure cut-off valve 320 closer to the rodless cavity, further reducing oil leakage. In addition, since the valve post oil circuit 340 also needs to meet the oil inlet requirement of the rodless cavity, the pressure cut-off valve 320 can be arranged to include two valve groups, one of which can be open in the oil inlet direction through the first one-way valve 321, and the other of which can be open in the oil return direction through the second one-way valve 322, and the second one-way valve 322 is set to be closed to preserve oil when the oil pressure does not reach the preset load pressure, thereby meeting the above requirement.

[0176] Further, when the telescopic arm 120 needs to be synchronously extended, the hydraulic reversing valve 330 is switched to communicate the working oil port with the oil inlet port of the hydraulic reversing valve 330, and the oil supply assembly 360 of the hydraulic control device 300 can supply oil to the rodless cavity from the valve group provided with the first one-way valve 321; when the telescopic arm 120 needs to be synchronously retracted, the hydraulic reversing valve 330 is switched to communicate the working oil port with the oil return port of the hydraulic reversing valve 330, so that the oil in the rodless cavity can flow from the valve group provided with the second one-way valve 322 to the oil return port of the hydraulic reversing valve 330, and finally flow back to the oil tank.

[0177] As Figure 14As shown, in the first embodiment of the present application, a descending valve assembly 380 is provided between the rodless chamber of the telescopic cylinder 310 and the hydraulic reversing valve 330. The reversing valve rear oil circuit 340 includes a descending valve front oil circuit 370 connecting the hydraulic reversing valve 330 and the descending valve assembly 380. The pressure cutoff valve 320 can be provided on the descending valve front oil circuit 370 and configured as a bidirectional check valve having a first check valve 321 and a second check valve 322. Using an existing bidirectional check valve as the pressure cutoff valve 320 provided on the reversing valve rear oil circuit 340 can reduce the number of in-house design and production steps. Specifically, in the two valve groups of the two-way one-way valve, not only the second one-way valve 322 but also the first one-way valve 321 can set the opening pressure. However, in order to ensure the conduction in the oil inlet direction, the first one-way valve 321 can be set to open at a smaller oil pressure, while the second one-way valve 322 is set to be conductive only when the oil pressure reaches a preset load pressure. The preset load pressure can be set to be greater than or equal to half of the total gravity of all telescopic arms 120, and less than the total gravity of all telescopic arms 120.

[0178] like Figure 15 As shown, in the second embodiment of the present application, a descending valve assembly 380 is provided between the rodless chamber of the telescopic cylinder 310 and the hydraulic reversing valve 330. The reversing valve rear oil circuit 340 includes a descending valve front oil circuit 370 connecting the hydraulic reversing valve 330 and the descending valve assembly 380. The one-way valve on the descending valve rear oil inlet circuit 382 in the descending valve assembly 380 is configured as a first one-way valve 321, and the second one-way valve 322 is provided on the descending valve rear oil return circuit 383 in the descending valve assembly 380. Therefore, the descending valve assembly 380 can be improved to meet the requirement of shutting off and maintaining oil pressure when the oil pressure does not reach a preset load pressure.

[0179] Specifically, the existing structure of the descending valve group 380 includes a descending valve body 381, a descending valve rear oil inlet circuit 382 and a descending valve rear oil return circuit 383. The descending valve rear oil inlet circuit 382 and the descending valve rear oil return circuit 383 are arranged in parallel, and one of the junction ends of the two is connected to the valve rear end of the descending valve body 381, and the other junction end is connected to the rodless chamber of the telescopic cylinder 310. The valve front end of the descending valve body 381 is connected to the hydraulic reversing valve 330 through the descending valve front oil circuit 370. The one-way valve on the descending valve rear oil inlet circuit 382 is set as a first one-way valve 321. The descending valve rear oil return circuit 383 originally only has a damper 384, so it can be obtained by adding a second one-way valve 322 to the descending valve rear oil return circuit 383.

[0180] like Figure 16As shown, in the third embodiment of the present application, the rodless cavity return oil circuit comprises a first valve-before-valve oil circuit connecting the oil tank and the return port of the hydraulic reversing valve 330, and the pressure cut-off valve 320 is arranged on the first valve-before-valve oil circuit 350. The pressure cut-off valve 320 is arranged as a third one-way valve 323 or a back pressure valve with adjustable opening pressure. Arranging the pressure cut-off valve 320 on the first valve-before-valve oil circuit 350 makes it unnecessary to consider the requirement of rodless cavity oil inlet, and the structure is relatively simple and the cost is relatively low. Specifically, the hydraulic control device 300 further comprises a second valve-before-valve oil circuit arranged between the oil supply assembly 360 and the oil inlet port of the hydraulic reversing valve 330, and the oil supply assembly 360 comprises an oil pump and a driving member for driving the oil pump to rotate.

[0181] In an embodiment of the present application, the first tensioning wheel 121 and the second tensioning wheel 122 on the same telescopic arm 120 are arranged on the same side, and the traction device 200 further comprises a first connecting assembly 230 and a second connecting assembly 240. The first connecting assembly 230 is arranged at the upper end of the inner side arm and the upper and lower ends thereof are respectively and one-to-one connected to the inner ends of the extension traction member 210 and the retraction traction member 220 on the same telescopic arm 120. The second connecting assembly 240 is arranged at the lower end of the outer side arm and the upper and lower ends thereof are respectively and one-to-one connected to the outer ends of the extension traction member 210 and the retraction traction member 220 on the same telescopic arm 120. The addition of the first connecting assembly 230 and the second connecting assembly 240 makes the traction module with both extension traction and retraction traction functions arranged in a ring shape on one side of the telescopic arm 120, which can reduce the arrangement of the connecting assembly compared with the scheme of separately arranging the extension traction member 210 and the retraction traction member 220 on both sides. It should be particularly noted that the arm adjacent to the inner side of the telescopic arm 120 on which the tensioning wheel corresponding to the current traction member is arranged is the inner side arm, and the arm adjacent to the outer side of the telescopic arm 120 on which the tensioning wheel corresponding to the current traction member is arranged is the outer side arm. The end on the inner side of the two ends of the extension traction member 210 and the retraction traction member 220 is the inner end of the extension traction member 210 and the retraction traction member 220, and the end on the outer side is the outer end of the extension traction member 210 and the retraction traction member 220.

[0182] In an embodiment of the present application, all the traction devices 200 are arranged on the same side of the lifting arm device 100. That is, the first tensioning wheel 121 and the second tensioning wheel 122 on all the telescopic arms 120 are also arranged on the same side, so that the other side of the lifting arm device 100 does not need to reserve space for the arrangement of the tensioning wheel, thereby reducing the size of the lifting arm device 100 and achieving the purpose of reducing production cost.

[0183] In an embodiment of the present application, the upper and lower ends of the telescopic arm 120 are both formed with notches on the same side, the telescopic arm 120 is provided with mounting shafts for mounting the first tensioning wheel 121 or the second tensioning wheel 122 on the inner wall corresponding to the notches, and the tensioning wheel sets on different telescopic arms 120 are sequentially staggered in the width direction of the lifting arm device 100. Through the addition of the notches, the tensioning wheels can be arranged not to protrude from the corresponding telescopic arm 120 in the height direction, thereby playing a certain protection role, and the arrangement of the mounting shafts can be facilitated, and the end of the mounting shaft can be directly connected to the adjacent side of the telescopic arm 120 without the notch. It should be particularly noted that the tensioning wheel set on the telescopic arm 120 is composed of the first tensioning wheel 121 and the second tensioning wheel 122 on one telescopic arm 120, and the first tensioning wheel 121 and the second tensioning wheel 122 in the tensioning wheel set should be arranged in the same vertical direction, and in addition, the outermost telescopic arm 120 does not need to be formed with a notch because it does not need to be provided with the first tensioning wheel 121 and the second tensioning wheel 122.

[0184] Referring to Figure 12 and Figure 13 In an embodiment of the present application, the first connecting assembly 230 includes a first connecting piece 231 and a second connecting piece 232, the first connecting piece 231 and the second connecting piece 232 are respectively connected to the inner ends of the extension traction member 210 and the retraction traction member 220 on the same telescopic arm 120 one by one, the first connecting piece 231 is arranged on the inner wall of the inner side arm, and the second connecting piece 232 is arranged on the outer wall of the inner side arm and located below the first connecting piece 231. That is, the first connecting assembly 230 is arranged in a split manner, and the first connecting piece 231 for connecting with the extension traction member 210 is arranged on the inner wall of the inner side arm, and the second connecting piece 232 for connecting with the retraction traction member 220 is arranged on the outer wall of the inner side arm, which can facilitate disassembly. Specifically, when assembling the traction member, since the first connecting assembly 230 is arranged close to the upper end of the telescopic arm 120, it is convenient to connect the extension traction member 210 to the inner side arm from the upper end of the inner side arm into the arm inner cavity, and in order to play a protection role, the first connecting piece 231 can be arranged on the inner wall of the inner side arm. However, connecting the retraction traction member 220 to the inner side arm from the lower end of the inner side arm into the arm inner cavity is time-consuming and laborious, and in order to facilitate the connection of the retraction traction member 220, the second connecting piece 232 can be arranged on the outer wall of the inner side arm. Specifically, the first connecting piece 231 can be fixed to the inner side arm by driving a fastener from the outside of the inner side arm, and the second connecting piece 232 can be fixed to the outer wall of the inner side arm by welding.

[0185] In an embodiment of the present application, the second connecting assembly 240 comprises a third connecting piece 241, the upper and lower ends of the third connecting piece 241 are connected with the outer ends of the extension traction piece 210 and the retraction traction piece 220 on the same telescopic section arm 120 respectively, and the third connecting piece 241 is arranged on the inner wall of the outer section arm. Since the second connecting assembly 240 is arranged close to the lower end of the telescopic section arm 120, the retraction traction piece 220 is connected with the inner cavity of the inner section arm from the lower end of the inner section arm, which is convenient, and the addition of the notch can facilitate the installation of the second connecting assembly 240 or the extension traction piece 210 in the inner cavity of the outer section arm, so that the second connecting assembly 240 can be arranged as an integrated third connecting piece 241, and the third connecting piece 241 is arranged on the inner wall of the outer section arm, so as to reduce the production cost and improve the production efficiency. Specifically, the third connecting piece 241 can be fixed to the outer section arm by fasteners punched from the outside of the outer section arm.

[0186] Specifically, the installation method of the traction piece can be: first, connecting the two ends of the extension traction piece 210 with the first connecting piece 231 and the third connecting piece 241 respectively; then, installing the first connecting piece 231 on the inner section arm and connecting one end of the retraction traction piece 220 with the second connecting piece 232; after the outer section arm is sleeved on the outside of the inner section arm, installing the third connecting piece 241 on the outer section arm and connecting the other end of the retraction traction piece 220 with the third connecting piece 241.

[0187] In an embodiment of the present application, the extension traction piece 210 is arranged as a chain, the chain has higher stability than the steel wire rope during lifting, the first connecting piece 231 comprises a fixed part 233 and a swing part 234, the fixed part 233 is arranged on the inner section arm and has a clamping space formed at the upper end, the lower end of the swing part 234 extends into the clamping space and is arranged on the fixed part 233 in a swing manner through a connecting pin shaft, and the upper end of the swing part 234 is connected with the chain. By additionally arranging the swing part 234 on the first connecting piece 231 and connecting the swing part 234 with the chain, the function of automatic correction can be achieved. Specifically, the upper end of the swing part 234 is detachably connected with the chain, and the retraction traction piece 220 can be arranged as a steel wire rope.

[0188] Further, the third connecting piece 241 can also comprise a fixed part 233 and a swing part 234, the fixed part 233 of the third connecting piece 241 is arranged on the outer section arm and has a clamping space formed at the upper end, the lower end of the swing part 234 extends into the clamping space and is arranged on the fixed part 233 in a swing manner through a connecting pin shaft, the upper end of the swing part 234 is connected with the chain, and the lower end of the fixed part 233 of the third connecting piece 241 is provided with a structure connectable with the retraction traction piece 220.

[0189] In the description of the application, it should be understood that the terms "first", "second" are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0190] In this application, unless otherwise expressly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and other terms should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or integrated; can be mechanically connected, or electrically connected or can communicate with each other; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise expressly limited. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0191] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the application. In this specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0192] Although the embodiments of the application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be construed as limiting the application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the application.

Claims

1. A mast-type aerial work platform, characterized in that: The mast-type aerial work platform comprises: A chassis device (700), wherein a storage space is enclosed on the chassis device (700); A lifting arm device (100), wherein the lower end of a basic arm section (110) of the lifting arm device (100) is arranged in the storage space, a telescopic arm section (120) of the lifting arm device (100) is arranged to be raised and lowered outside the basic arm section (110), and a trigger block (130) is provided on the circumference of the outermost telescopic arm section (120); A platform body (400) is provided on the outermost telescopic arm (120); A storage position detection device (600) is provided on the side of the storage space corresponding to the trigger block (130) and can be triggered under the lateral abutment of the trigger block (130); The mast-type aerial work platform further comprises a hydraulic drive system (300), a weighing device (500), a pressure detection device, an abnormal lifting alarm device and a control device. The hydraulic drive system (300) can drive the telescopic boom (120) to lift and lower. The weighing device (500) is used to detect the weight of the platform body (400). The pressure detection device is used to detect the oil pressure of the telescopic oil cylinder (310) in the hydraulic drive system (300). The control device is respectively connected to the weighing device (500), the pressure detection device and the abnormal lifting alarm device and is configured as follows: When it is determined that the platform body (400) is in a lifting stop state, obtaining a first pressure value detected by a pressure detection device and a first weight value detected by a weighing device (500); After a first preset time interval, obtaining a second pressure value detected by the pressure detection device and a second weight value detected by the weighing device (500); When the deviation between the first pressure value and the second pressure value is greater than a preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than a preset weight deviation threshold, it is determined that the platform body (400) is in an abnormal lifting state and the abnormal lifting alarm device is controlled to provide an abnormal lifting prompt.

2. The mast-type aerial work platform according to claim 1, characterized in that: The abnormal lifting state includes an abnormal descending state and an abnormal ascending state; when the deviation between the first pressure value and the second pressure value is greater than a preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than a preset weight deviation threshold, determining that the platform body (400) is in an abnormal lifting state and controlling the abnormal lifting alarm device to issue an abnormal lifting prompt, including: When the first pressure value is greater than the second pressure value and the deviation between the first pressure value and the second pressure value is greater than a preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than a preset weight deviation threshold, determining that the platform body (400) is in an abnormal descent state and controlling the abnormal lifting alarm device to issue an abnormal descent prompt; or When the first pressure value is less than the second pressure value and the deviation between the first pressure value and the second pressure value is greater than a preset pressure deviation threshold, and the deviation between the first weight value and the second weight value is less than a preset weight deviation threshold, it is determined that the platform body (400) is in an abnormal ascent state and the abnormal ascent alarm device is controlled to issue an abnormal ascent prompt.

3. The mast-type aerial work platform according to claim 1, characterized in that: The step of determining that the platform body (400) is in a lifting stop state includes: In the case where no trigger signal from the storage position detection device (600) is received, determining that the platform body (400) is in a lifted state; When no lifting signal instruction is received for a second preset time period, it is determined that the platform body (400) is in a lifting stop state.

4. The mast-type aerial work platform according to claim 1, characterized in that: The control device is further configured to: obtaining a third weight value detected by the weighing device (500); Determining that the third weight value is less than a preset reverse force judgment weight threshold, wherein the preset reverse force judgment weight threshold is less than a predetermined empty weight value of the platform body (400), the empty weight value being the weight value of the platform body (400) when in an empty lifting state and with no interfering objects below the platform body (400); It is determined that there is an interference object below the platform body (400) and the movement of the mast-type aerial work platform is restricted.

5. The mast-type aerial work platform according to claim 4, characterized in that: After obtaining the third weight value detected by the weighing device (500), the method further includes: If the third weight value is greater than the empty weight value, determining a weight difference between the third weight value and the empty weight value; Determining the ratio of the weight difference to the preset maximum load-bearing weight of the platform body (400) to obtain a load rate; When the load rate is greater than a preset load rate threshold, it is determined that the platform body (400) is overloaded and the movement of the mast-type aerial work platform is restricted.

6. The mast-type aerial work platform according to claim 5, characterized in that: The control device is further configured to: When the third weight value is greater than or equal to the preset reverse force judgment weight threshold, and / or the load rate is less than or equal to the preset load rate threshold, it is determined that the platform body (400) is in a normal working state and the movement of the mast-type aerial work platform is not restricted.

7. The mast-type aerial work platform according to any one of claims 1 to 6, characterized in that: The storage space is formed by laterally enclosing the chassis device (700) by installing a side plate (710). The storage position detection device (600) includes a swing-rod type position detection switch. The main body (610) of the position detection switch is arranged on a side of the installation side plate (710) facing away from the storage space. The installation side plate (710) is provided with an installation opening (711) for the swing-rod portion (620) of the position detection switch to extend toward the storage space. The trigger block (130) can abut against the swing-rod portion (620).

8. The mast-type aerial work platform according to claim 7, characterized in that: The mounting opening (711) is arranged on one side of the lifting arm device (100), and the rocker portion (620) includes a rocker mounting shaft provided on the main body (610) and extending from the mounting opening (711) to the storage space, and a rocker body rotatably sleeved on the rocker mounting shaft. The trigger block (130) is provided on the side of the outermost telescopic arm (120) facing the mounting opening (711), and is formed with an abutting surface (131) abutting against the rocker body laterally. The abutting surface (131) includes a chamfered inclined surface (132) and a vertical plane (133) arranged in sequence from bottom to top. The chamfered inclined surface (132) can press down the rocker body and guide the rocker body to the vertical plane (133), so that the vertical plane (133) can laterally press against the rocker body when the outermost telescopic arm (120) is lowered to the storage position.

9. The mast-type aerial work platform according to claim 1, characterized in that: The platform body (400) and the outermost telescopic arm (120) are provided with a first connecting portion (410) and a second connecting portion (140) in a one-to-one correspondence. The weighing device (500) includes a pin shaft weighing sensor that is communicatively connected to the control device. The pin shaft weighing sensor is connected in series with the first connecting portion (410) and the second connecting portion (140). A contact block (150) is also provided on the outermost telescopic arm (120). The contact block (150) is located on the lower side of the second connecting portion (140) and is provided with a nylon contact layer on the side facing the platform body (400). The nylon contact layer is used to make lateral contact with the base frame (430) of the platform body (400).

10. The mast-type aerial work platform according to any one of claims 1 to 6, characterized in that: The number of the telescopic joint arms (120) is at least two, and at least two of the telescopic joint arms (120) are sequentially nested on the outside of the basic joint arm (110), and the telescopic joint arms (120) located on the inside are each provided with a first tensioning wheel (121) and a second tensioning wheel (122) at the upper and lower ends, respectively. The mast-type aerial work platform further comprises: The traction device (200) comprises an extending traction member (210) and a retracting traction member (220), wherein the extending traction member (210) is wound around the first tensioning wheel (121) and its two ends are respectively connected to the joint arms on two adjacent sides, and the retracting traction member (220) is wound around the second tensioning wheel (122) and its two ends are respectively connected to the joint arms on two adjacent sides; The hydraulic drive system (300) comprises a telescopic oil cylinder (310) provided on the basic boom (110) and drivingly connected to the telescopic boom (120) located at the innermost side, and a pressure cut-off valve (320) in a rodless chamber return oil circuit connected to the telescopic oil cylinder (310), wherein the pressure cut-off valve (320) is set to be conductive when the oil pressure in the rodless chamber return oil circuit reaches a preset load pressure.

11. The mast-type aerial work platform according to claim 10, characterized in that: The rodless chamber oil return oil circuit includes a working oil port connected to a hydraulic reversing valve (330) and a reversing valve rear oil circuit (340) of the rodless chamber of the telescopic oil cylinder (310). The pressure cut-off valve (320) is provided on the reversing valve rear oil circuit (340), and the pressure cut-off valve (320) includes two valve groups arranged in parallel, one of which includes a first one-way valve (321) conducting in the oil inlet direction of the telescopic oil cylinder (310), and the other includes a second one-way valve (322) conducting in the oil outlet direction of the telescopic oil cylinder (310). The second one-way valve (322) is set to conduct when the oil pressure in the reversing valve rear oil circuit (340) reaches a preset load pressure.

12. The mast-type aerial work platform according to claim 11, characterized in that: A descending valve group (380) is provided between the rodless chamber of the telescopic oil cylinder (310) and the hydraulic reversing valve (330), and the reversing valve rear oil circuit (340) includes a descending valve front oil circuit (370) connecting the hydraulic reversing valve (330) and the descending valve group (380); The pressure cut-off valve (320) is provided on the oil circuit (370) before the descending valve and is configured as a two-way one-way valve having the first one-way valve (321) and the second one-way valve (322); or the one-way valve on the oil inlet circuit (382) after the descending valve in the descending valve group (380) is configured as the first one-way valve (321), and the second one-way valve (322) is provided on the oil return circuit (383) after the descending valve in the descending valve group (380).

13. The mast-type aerial work platform according to claim 10, characterized in that: The rodless chamber oil return oil circuit includes a first reversing valve front oil circuit (350) connected to an oil tank and an oil return port of a hydraulic reversing valve (330); the pressure cut-off valve (320) is arranged on the first reversing valve front oil circuit (350); and the pressure cut-off valve (320) is configured as a third one-way valve (323) or a back pressure valve with adjustable opening pressure.

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