Low space operation forklift and control method

Abstract

The invention discloses a forklift for low space operation and a control method. The forklift comprises a forklift body, a first sensor is arranged on the forklift body, a gantry is within the height range of zero to H, the first sensor keeps a signal state, and after the gantry is larger than H, the first sensor is in a non-signal state; the turnover mechanism comprises a fixing frame and a rotating frame, a turnover oil cylinder is arranged on the fixing frame to drive the rotating frame to turn over, the rotating frame is within the range from zero degree to alpha degree, the second sensor is kept in a signal state, and the second sensor is in a signal-free state after the rotating frame is larger than alpha degree; and the control system comprises an automatic control module and a manual operation module, the control system is in signal connection with the first sensor and the second sensor, and when the automatic control module is in an open state, the control system controls the portal frame and the rotating frame to act or stop acting according to the signal states of the first sensor and the second sensor. The problem that high goods cannot enter a low door is solved, the operation cost of an enterprise is greatly saved, and the applicability is high.

Description

Technical Field

[0001] The present application relates to the technical field of forklifts, and in particular to a low-space operation forklift and a control method thereof. Background Art

[0002] In the process of cargo handling, forklifts are commonly used to transport large cargo into a space. However, if the door of the space is relatively low and the cargo is higher than the door, it is generally impossible to move it in. Figure 1 As shown, there are many such scenarios, such as putting goods into a train carriage, putting goods into a warehouse, etc. They all have one thing in common: the entrance door is relatively short, even shorter than the goods, and the goods cannot be put in by normal means.

[0003] The common solution at present is to deliver the goods to the door by forklift, and then put the goods on a pallet or cart with wheels. According to the weight of the goods, 2 or more workers are assigned to manually put down the goods (or tilt the goods. If it is tilted, someone always needs to hold it up), and then manually push the goods into the space that needs to be entered. After entering the space, the goods are manually lifted up and straightened. This has low work efficiency, wastes manpower and material resources, and has high labor costs.

[0004] Therefore, in view of the above technical problems, how to enable high cargo to pass through a low door efficiently is a technical problem that technical personnel in this field need to solve. Summary of the invention

[0005] The purpose of this application is to provide a low-space operation forklift and a control method, which solves the problem that high goods cannot enter low doors, eliminates the need for renovation of storage and transfer sites such as warehouses and cargo boxes, greatly saves enterprise operating costs, and has strong applicability.

[0006] To achieve the above objectives, the present application provides a low-space operation forklift, comprising:

[0007] A vehicle body, wherein a liftable gantry is provided at the front end of the vehicle body, and a first sensor for detecting a height change thereof is provided on the gantry. When the gantry is within a height range of zero to H, the first sensor maintains a signal state, and when the lifting height of the gantry is greater than H, the first sensor is in a no-signal state;

[0008] The turning mechanism comprises a fixed frame connected to the door frame and a rotating frame rotatably arranged on the fixed frame, the fixed frame is provided with a turning cylinder, the telescopic end of the turning cylinder is connected to the rotating frame to drive the rotating frame to turn over, and also comprises a second sensor for detecting the turning angle of the rotating frame, the second sensor maintains a signal state when the rotating frame is within the rotation angle range of zero to α degrees, and the second sensor is in a no-signal state when the rotation angle of the rotating frame is greater than α degrees;

[0009] A control system includes an automatic control module and a manual operation module, wherein the control system is connected to the first sensor and the second sensor signals, and when the automatic control module is turned on, the control system controls the gantry and the rotating frame to move or stop moving according to the signal states of the first sensor and the second sensor; wherein, at any moment during the movement of the gantry or the rotating frame, the automatic control module turns off or operates the manual operation module, thereby controlling the gantry and the rotating frame to stop moving.

[0010] Preferably, the fixing frame is arranged in a U-shape, and a connecting edge of the U-shaped fixing frame is provided with a mounting hook fixedly mounted to the door frame, and two parallel edges of the U-shaped fixing frame extend in a direction away from the door frame.

[0011] Preferably, the rotating frame includes side edges corresponding to the two parallel edges and a fixed edge connecting the two side edges, a bent bottom edge is provided at the lower side of the fixed edge, and the bottom edge and the two side edges are used for wrapping goods.

[0012] Preferably, the extending ends of the two parallel sides are provided with a first rotating hole for installing the rotating frame, and the rotating frame rotates around the line connecting the two first rotating holes as the axis. The parallel sides are also provided with a second rotating hole, and the second rotating hole is used for rotatably installing the flip cylinder.

[0013] Preferably, a third rotating hole corresponding to the first rotating hole is provided on the side, and a fourth rotating hole corresponding to the second rotating hole is also provided on the side, and the fourth rotating hole is used to install the telescopic end of the turning cylinder.

[0014] A control method, applicable to the low-space operation forklift described above, comprising:

[0015] In the operation state of the forklift, it is determined whether the automatic control module is turned on. If it is turned on, the signal state of the first sensor is obtained. The first sensor is in a signal state, which is recorded as A=1, and the first sensor is in a no-signal state, which is recorded as A=0;

[0016] If A=1, the gantry is controlled to continue to rise until A=0, the gantry stops rising and the rotating frame is controlled to flip; if A=0, the rotating frame is controlled to flip;

[0017] During the turning process of the rotating frame, the signal state of the second sensor is obtained, and the signal state of the second sensor is recorded as C=1, and the signal state of the second sensor is recorded as C=0;

[0018] If C=1, the rotating frame is controlled to continue flipping until C=0, and the rotating frame stops flipping; if C=0, the rotating frame is controlled to stop flipping;

[0019] Wherein, at any time during the operation of the gantry or the rotating frame, if the automatic control module is turned off or manual operation intervenes, the gantry or the rotating frame stops operating.

[0020] Preferably, when the forklift is in operation, it is determined whether the automatic control module is turned on, and if not, the manual operation module is executed.

[0021] Preferably, before the step of determining whether the automatic control module is turned on in the forklift operation state, the method further comprises:

[0022] When the forklift is driven to pick up goods in the initial states of the gantry and the rotating frame, the initial state of the gantry is that the lifting height of the gantry is zero, and the initial state of the rotating frame is that the rotation angle of the rotating frame is zero.

[0023] Preferably, when the lifting height of the gantry is H or is greater than H, the circular track of the maximum diameter formed by the flipping of the flipping mechanism is separated from the ground.

[0024] Compared with the prior art, the technical solution provided by this application has at least the following beneficial effects:

[0025] The present application can flip the goods to a certain angle through the flipping mechanism so that the total height of the goods is lower than the height of the entrance door. At the same time, the control system can also be used to realize automatic lifting and flipping of the goods. Specifically, after the forklift picks up the goods, the control system controls the door frame to lift or controls the rotating frame to flip according to the signal status of the first sensor and the second sensor, so that the door frame automatically lifts the goods to a suitable height and the rotating frame automatically flips to a suitable angle to meet the height requirement of the entrance door, simplifying the operation process, reducing the difficulty of operation, improving work efficiency, and having a high degree of automation; in addition, during the process of door frame lifting or rotating frame flipping, the door frame or rotating frame can be stopped immediately by turning off the automatic control module or operating the manual operation module, which is safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0027] Figure 1 It is a schematic diagram of a structure in which the cargo is higher than the entrance door in the prior art;

[0028] Figure 2 A schematic diagram of the structure of a low-space operation forklift provided in an embodiment of the present application;

[0029] Figure 3 A schematic diagram of the structure of the flipping mechanism provided in the embodiment of the present application;

[0030] Figure 4 A schematic diagram of the structure of the fixing frame provided in the embodiment of the present application;

[0031] Figure 5 A schematic diagram of the structure of the rotating frame provided in an embodiment of the present application;

[0032] Figure 6 A schematic diagram of the structure of a low-space operation forklift provided in an embodiment of the present application after picking up cargo;

[0033] Figure 7 A schematic diagram of the structure of a low-space operation forklift provided in an embodiment of the present application after picking up cargo and lifting it to a certain height;

[0034] Figure 8 A schematic diagram of the structure of a low-space operation forklift provided in an embodiment of the present application after picking up cargo, lifting it and flipping it;

[0035] Fig. 9 A flow chart of the control method provided in an embodiment of the present application.

[0036] In the figure:

[0037] 1-body; 11-gantry; 2-control system; 3-turning mechanism; 31-fixed frame; 311-connecting edge; 312-parallel edge; 313-first rotating hole; 314-second rotating hole; 32-turning cylinder; 33-rotating frame; 331-fixed edge; 332-side edge; 333-third rotating hole; 334-fourth rotating hole; 335-bottom edge. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] It should be noted that in this embodiment, the directions or positional relationships indicated by "upper", "lower", "front", "back", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present application. In addition, "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0041] Please refer to Figure 2 In this embodiment, a low-space operation forklift is provided, which includes a body 1, a turning mechanism 3 and a control system 2. The body 1 is a conventional counterbalanced stacker. A liftable gantry 11 is provided at the front end of the body 1. A first sensor for the detector height is provided on the gantry 11. When the gantry 11 is in the initial retracted state, that is, when the lifting height of the gantry 11 is zero, the first sensor is in a signal state. When the gantry 11 starts to lift and lifts to a certain height H, the gantry 11 is within the height range of zero to H, and the first sensor maintains a signal state. The signal state of the first sensor is A=1; when the gantry 11 continues to lift and the lifting height is greater than H, the first sensor is in a no-signal state. The no-signal state of the first sensor is A=0. It should be noted that the height H detected by the first sensor can be considered as a design, which is mainly specially set according to the size of the goods and the height of the entrance door at the actual site, and will not be described in detail here.

[0042] The turning mechanism 3 includes a fixed frame 31 and a rotating frame 33. The fixed frame 31 is connected to the door frame 11, and the rotating frame 33 is rotatably arranged on the fixed frame 31, so that the lifting of the door frame 11 drives the fixed frame 31 and the rotating frame 33 to be lifted, thereby driving the goods on the rotating frame 33 to be lifted. In addition, please refer to Figure 3, a turning cylinder 32 is also provided on the fixed frame 31, and the telescopic end of the turning cylinder 32 is connected to the rotating frame 33, so as to drive the rotating frame 33 to turn over. The turning mechanism 3 also includes a second sensor for detecting the turning angle of the rotating frame 33. The second sensor can be arranged on the fixed frame 31. When the rotating frame 33 is within the rotation angle range of zero to α degrees, the first sensor maintains a signal state, and this state is set as C=1. When the rotating frame 33 continues to turn over and the turning angle exceeds α degrees, the second sensor is in a no-signal state, and this state is recorded as C=0; wherein, the angle α is not set arbitrarily, but is set according to the entrance height and cargo size of the work site, to ensure that when it rotates to an angle of α, the cargo is laid down to this angle and can smoothly enter the entrance door.

[0043] Of course, the turning angle range of the rotating frame 33 is limited by the inherent stroke of the turning cylinder 32. Its turning range can be quantitatively described as a counterclockwise rotation from zero degrees in the initial state to a maximum of β degrees, where Figure 3 The rotating frame 33 in the figure is defined as the initial state, that is, the goods are placed vertically on the rotating frame 33 as a whole. When working, the rotating frame 33 will rotate counterclockwise. The initial state is defined as zero degrees, and counterclockwise rotation to a certain angle is defined as α degrees. Note that α degrees must be less than β degrees.

[0044] In addition, when the flipping mechanism 3 also includes necessary components such as hydraulic pipelines, electrical circuits, etc., they will not be described in detail here, and it is sufficient to ensure that the above functions can be fully realized.

[0045] The control system 2 includes an automatic control module and a manual operation module. The control system 2 is connected to the first sensor and the second sensor signals. When the automatic control module is turned on, the control system 2 can control the gantry 11 and the rotating frame 33 to move or stop according to the signal status of the first sensor and the second sensor. It should be pointed out that the automatic control module and the manual operation module can be two separately controlled systems, and the priority of the manual operation module is higher than that of the automatic control module, that is, any manual operation has a higher priority than the automatic operation.

[0046] Among them, an on / off button is provided on the automatic control module to start or turn off the "one-key flip" function. When the button is pressed, the automatic control module is turned on, and the "one-key flip" function is activated. The activated state is recorded as B=1; when the button is released, the "one-key flip" function is deactivated, and the deactivated state is recorded as B=0.

[0047] It should be pointed out that at any time during the operation of the gantry 11 or the rotating frame 33, if the automatic control module is turned off or the manual operation module is operated, the gantry 11 and the rotating frame 33 will be controlled to stop operating, ensuring that during the automatic operation of the "one-key flip", the operation can be stopped in time if any accident occurs.

[0048] In summary, the present application can flip the goods to a certain angle through the flipping mechanism 3 so that the total height of the goods is lower than the height of the entrance door. At the same time, the control system 2 can also be used to realize automatic lifting and flipping of the goods. Specifically, after the forklift picks up the goods, according to the signal status of the first sensor and the second sensor, the control system 2 controls the door frame 11 to lift or controls the rotating frame 33 to flip, so that the door frame 11 automatically lifts the goods to a suitable height and the rotating frame 33 automatically flips to a suitable angle to meet the height requirement of the entrance door, simplify the operation process, reduce the difficulty of operation, improve work efficiency, and have a high degree of automation. In addition, during the lifting of the door frame 11 or the flipping of the rotating frame 33, the door frame 11 or the rotating frame 33 can be stopped immediately by turning off the automatic control module or operating the manual operation module, which is safer.

[0049] Please refer to Figure 4 The fixing frame 31 is in a U-shape as a whole. The connecting edge 311 of the U-shaped fixing frame 31 is provided with a mounting hook fixedly mounted on the gantry 11, so that the flipping mechanism 3 and the gantry 11 can be detached. On the basis of retaining the manual operation module, after the front flipping mechanism 3 is removed, the fork can be hung and used as a conventional counterbalanced stacker, so that one machine can be used for multiple purposes. The two parallel edges 312 of the U-shaped fixing frame 31 extend in a direction away from the gantry 11, and there is a certain width between the two parallel edges 312, which is greater than the width of the rotating frame 33.

[0050] Please refer to Figure 5 The rotating frame 33 includes a side edge 332 corresponding to the two parallel edges 312 and a fixed edge 331 connecting the two side edges 332. A bent bottom edge 335 is provided at the lower side of the fixed edge 331. The bottom edge 335 and the two side edges 332 are used to wrap the goods. The fixed edge 331 and the bottom edge 335 are in an "L" shape, and the two side edges 332 and the fixed edge 331 are in a "U" shape. The purpose of this shape is to ensure that the goods will not roll down during the process of forking and laying down, so as to ensure safety. In addition, there is also a certain width between the two side edges 332. This width is designed according to the size of the goods to ensure that the goods can be included in its outline.

[0051] Please refer to Figure 4 and Figure 5The extending ends of the two parallel sides 312 are provided with first rotating holes 313 for installing the rotating frame 33. The rotating frame 33 rotates with the connecting line of the two first rotating holes 313 as the axis. The parallel sides 312 are also provided with second rotating holes 314, which are used for rotating the turning cylinder 32. The side 332 is provided with a third rotating hole 333 corresponding to the first rotating hole 313, and the side 332 is also provided with a fourth rotating hole 334 corresponding to the second rotating hole 314, which is used for installing the telescopic end of the turning cylinder 32. Corresponding mounting holes are also provided at both ends of the turning cylinder 32, which can be rotatably connected to the fixed frame 31 and the rotating frame 33 respectively through a pin shaft, which will not be repeated here.

[0052] The fixed frame 31 and the rotating frame 33 are integrally formed into a frame structure, which is as simple, economical and practical as possible while ensuring sufficient strength.

[0053] The forklift of the present application has a cargo flipping function, which can replace traditional manual handling. While greatly saving labor costs, it can make operations simpler, safer and more efficient. The base vehicle model counterbalanced stacker of the present application adopts a conventional vehicle model, and only some necessary modifications are made, so it can be produced on a large scale with a short production cycle. At the same time, there are fewer specialized parts, the production cost is relatively low, and the cost performance is high.

[0054] The present application also provides a control method, which can be applied to the above-mentioned low-space operation forklift, including:

[0055] In the running state of the forklift, it is determined whether the automatic control module is turned on. If it is turned on, the signal state of the first sensor is obtained. The first sensor is in a signal state as A=1, and the first sensor is in a no-signal state as A=0;

[0056] If A=1, the gantry 11 is controlled to continue to rise until A=0, the gantry 11 stops rising, and the rotating frame 33 is controlled to flip; if A=0, the rotating frame 33 is controlled to flip;

[0057] The signal state of the second sensor is obtained during the turning process of the rotating frame 33. The signal state of the second sensor is recorded as C=1, and the signal state of the second sensor is recorded as C=0;

[0058] If C=1, the rotating frame 33 is controlled to continue flipping until C=0, and the rotating frame 33 stops flipping; if C=0, the rotating frame 33 is controlled to stop flipping;

[0059] Among them, at any time during the operation of the gantry 11 or the rotating frame 33, if the automatic control module is turned off or manual operation intervenes, the gantry 11 or the rotating frame 33 stops operating.

[0060] Please refer to Fig. 9When the forklift is powered on and the system is fault-free, determine whether the automatic control module is turned on. If it is turned on, activate the "one-key flip" function; if it is not turned on, execute the manual operation module. The operation process under the manual operation module can be completed manually according to the process like a traditional forklift. Of course, before determining whether the automatic control module is turned on, you need to drive the forklift to pick up the goods in the initial state of the door frame 11 and the rotating frame 33. Please refer to Figure 6 , and then execute the "one-key flip" function.

[0061] The initial state of the gantry 11 is that the lifting height of the gantry 11 is zero, and the initial state of the rotating frame 33 is that the rotation angle of the rotating frame 33 is zero, that is, Figure 6 In this state, the overturning action cannot be performed because the goods will touch the ground when overturning, so you must enter the step of lifting the mast 11, please refer to Figure 7 , operate the forklift to lift to an appropriate height. This height needs to be designed according to different application scenarios and different cargo sizes. The appropriate height H introduced above can be calculated to ensure that when the height is lifted to H or even higher, the flip mechanism 3 performs a flipping action. For details, please refer to Figure 8 At this time, the circular track of the maximum diameter formed by the flipping mechanism 3 is separated from the ground, and the flipping mechanism 3 and the goods will not be scratched against the ground.

[0062] During the process of automatic lifting of the gantry 11 and automatic flipping of the rotating frame 33, a judgment is designed to cancel the "one-key flip" function B=0 or any manual operation intervention", which means that in order to ensure the safety of the operation process, any manual operation intervention will terminate the automatic operation.

[0063] From the above, it can be seen that the "one-key flip" semi-automatic function of the present application can simplify the operation process, reduce the difficulty of operation, and improve work efficiency; at the same time, the manual operation function has a higher priority than the "one-key flip" semi-automatic operation function. During the execution of the "one-key flip" function, any manual operation can terminate the automatic operation, which is highly safe.

[0064] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0065] Specific examples are used herein to illustrate the principles and implementation methods of the present application, and the description of the above embodiments is only used to help understand the method and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A low-space operation forklift, characterized in that: include: A vehicle body (1), wherein a liftable gantry (11) is provided at the front end of the vehicle body (1), and a first sensor for detecting a height change of the gantry (11) is provided on the gantry (11); when the gantry (11) is within a height range of zero to H, the first sensor maintains a signal state; when the gantry (11) is lifted to a height greater than H, the first sensor is in a no-signal state; A turning mechanism (3), comprising a fixed frame (31) connected to the door frame (11) and a rotating frame (33) rotatably arranged on the fixed frame (31), wherein the fixed frame (31) is provided with a turning cylinder (32), and the telescopic end of the turning cylinder (32) is connected to the rotating frame (33) to drive the rotating frame (33) to turn over, and further comprising a second sensor for detecting the turning angle of the rotating frame (33), wherein the second sensor maintains a signal state when the rotating frame (33) is within a rotation angle range of zero to α degrees, and the second sensor is in a signal-free state when the rotation angle of the rotating frame (33) is greater than α degrees; A control system (2) comprises an automatic control module and a manual operation module, wherein the control system (2) is connected to the first sensor and the second sensor signals, and when the automatic control module is turned on, the control system (2) controls the gantry (11) and the rotating frame (33) to move or stop moving according to the signal states of the first sensor and the second sensor; wherein, at any moment during the movement of the gantry (11) or the rotating frame (33), the automatic control module turns off or operates the manual operation module, thereby controlling the gantry (11) and the rotating frame (33) to stop moving.

2. The low-slung space operation forklift according to claim 1, characterized in that: The fixing frame (31) is arranged in a U-shape, and a connecting edge (311) of the U-shaped fixing frame (31) is provided with a mounting hook fixedly mounted to the door frame (11), and two parallel edges (312) of the U-shaped fixing frame (31) extend in a direction away from the door frame (11).

3. The low-slung space operation forklift according to claim 2, characterized in that: The rotating frame (33) comprises side edges (332) corresponding to the two parallel edges (312) and a fixed edge (331) connecting the two side edges (332); a bent bottom edge (335) is provided at the lower side of the fixed edge (331); the bottom edge (335) and the two side edges (332) are used for wrapping goods.

4. The low-slung space operation forklift according to claim 3, characterized in that: The extending ends of the two parallel sides (312) are provided with first rotating holes (313) for mounting the rotating frame (33); the rotating frame (33) rotates around a line connecting the two first rotating holes (313) as an axis; and the parallel sides (312) are also provided with second rotating holes (314) for rotatably mounting the tilting cylinder (32).

5. The low-slung space operation forklift according to claim 4, characterized in that: The side edge (332) is provided with a third rotating hole (333) corresponding to the first rotating hole (313), and the side edge (332) is also provided with a fourth rotating hole (334) corresponding to the second rotating hole (314), and the fourth rotating hole (334) is used to install the telescopic end of the tilting cylinder (32).

6. A control method, characterized in that: The low-slung space operation forklift according to any one of claims 1 to 5 comprises: In the operation state of the forklift, it is determined whether the automatic control module is turned on. If it is turned on, the signal state of the first sensor is obtained. The first sensor is in a signal state, which is recorded as A=1, and the first sensor is in a no-signal state, which is recorded as A=0; If A=1, the gantry (11) is controlled to continue to rise until A=0, the gantry (11) stops rising, and the rotating frame (33) is controlled to flip; if A=0, the rotating frame (33) is controlled to flip; During the turning process of the rotating frame (33), a signal state of the second sensor is obtained, where the second sensor is in a signal state as C=1, and the second sensor is in a no-signal state as C=0; If C=1, the rotating frame (33) is controlled to continuously flip until C=0, and the rotating frame (33) stops flipping; if C=0, the rotating frame (33) is controlled to stop flipping; Wherein, at any time during the operation of the gantry (11) or the rotating frame (33), if the automatic control module is shut down or manual operation intervenes, the gantry (11) or the rotating frame (33) stops operating.

7. The control method according to claim 6, characterized in that: When the forklift is in operation, determine whether the automatic control module is turned on. If not, execute the manual operation module.

8. The control method according to claim 6, characterized in that: Before the step of determining whether the automatic control module is turned on in the forklift operation state, the method further includes: When the forklift is driven to pick up goods in the initial state of the gantry (11) and the rotating frame (33), the initial state of the gantry (11) is that the lifting height of the gantry (11) is zero, and the initial state of the rotating frame (33) is that the rotation angle of the rotating frame (33) is zero.

9. The control method according to claim 6, characterized in that: When the lifting height of the door frame (11) is H or is greater than H, the circular track with the maximum diameter formed by the flipping of the flipping mechanism (3) is separated from the ground.

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