Low profile space operating fork truck and control method

Abstract

The application discloses a low-space operation forklift and a control method. The forklift comprises a vehicle body, a first sensor arranged on the vehicle body, a portal frame with a height ranging from 0 to H, the first sensor maintaining a signal state, and the first sensor being in a no-signal state when the height is greater than H; a turnover mechanism comprising a fixed frame and a rotating frame, a turnover oil cylinder arranged on the fixed frame to drive the rotating frame to turn over, the rotating frame ranging from 0 degrees to alpha degrees, a second sensor maintaining a signal state, and the second sensor being in a no-signal state when the rotating frame is greater than alpha degrees; and a control system comprising an automatic control module and a manual operation module, the control system being signal-connected with the first sensor and the second sensor, and in an open state of the automatic control module, the control system controls the portal frame and the rotating frame to act or stop acting according to the signal state of the first sensor and the second sensor. The application solves the problem that high goods cannot enter a low door, greatly saves enterprise operation cost, and has strong applicability.

Description

TECHNICAL FIELD

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

[0002] In the process of cargo handling, forklifts are commonly used handling vehicles. A forklift is used to carry a large piece of cargo into a space, but the door of the space is relatively low, and the cargo is higher than the door, so it is generally impossible to carry it in, such as Figure 1 As shown in the figure, there are many such scenarios, such as putting cargo into a train compartment or a warehouse, etc., which all have the common feature that the entrance door is relatively low and lower than the cargo, and it is impossible to put the cargo in using the normal way.

[0003] The current common solution is to transport the cargo to the door by a forklift, then put the cargo on a tray or a cart with wheels, according to the weight of the cargo, 2 or more workers are equipped to manually lay down the cargo (or put the cargo obliquely, if it is oblique, it always needs someone to hold it), and then manually push the cargo into the space that needs to be entered, after entering the space, manually support the cargo to put it right, which is low in work efficiency, wastes manpower and material resources, and is high in labor cost.

[0004] Therefore, in view of the above technical problems, how to make high cargo pass through a low door efficiently is a technical problem to be solved by those skilled in the art. SUMMARY

[0005] The purpose of the present application is to provide a low-space operation forklift and a control method, which solves the problem that high cargo cannot enter a low door, eliminates the modification of storage and transfer places such as warehouses and containers, greatly saves enterprise operating costs, and has strong applicability.

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

[0007] A vehicle body is provided with a liftable mast at the front end, a first sensor for detecting the height change of the mast is arranged on the mast, the height of the mast ranges from 0 to H, the first sensor maintains a signal state, and when the lifting height of the mast is greater than H, the first sensor is in a no-signal state.

[0008] The turning mechanism includes a fixed frame connected to the door frame and a rotating frame rotatably mounted 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, and further includes 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 is in a no-signal state when the rotation angle of the rotating frame exceeds α degrees;

[0009] A control system includes an automatic control module and a manual operation module. The control system is connected to the signals of the first sensor and the second sensor. When the automatic control module is turned on, the control system controls the movement or stopping of the gantry and the rotating frame according to the signal status 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 movement of the gantry and the rotating frame.

[0010] Preferably, the fixing frame is U-shaped, the connecting edge of the U-shaped fixing frame is provided with a mounting hook fixedly mounted on the door frame, and the 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 on 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. A second rotating hole is also provided on the parallel sides, and the second rotating hole is used for rotatably installing the flip cylinder.

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

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

[0015] When the forklift is in operation, 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. If the first sensor is in a signal state, it is recorded as A=1; if the first sensor is in a no-signal state, it is recorded as A=0;

[0016] If A=1, the gantry is controlled to continuously lift until A=0, the gantry stops lifting and the rotating frame is controlled to flip; if A=0, the rotating frame is controlled to flip;

[0017] The signal state of a second sensor is acquired during the flipping of the rotating frame, the second sensor is in a signal state and is marked as C=1, and the second sensor is in a non-signal state and is marked as C=0;

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

[0019] At any time during the action of the gantry or the rotating frame, if the automatic control module is closed or manual operation is intervened, the gantry or the rotating frame stops action.

[0020] Preferably, whether the automatic control module is opened is judged in the forklift running state, and if not, the manual operation module is executed.

[0021] Preferably, before the step of judging whether the automatic control module is opened in the forklift running state, the method further comprises:

[0022] The forklift is driven to fork the goods in the initial state 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 rotating angle of the rotating frame is zero.

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

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

[0025] The application can flip the goods by a flipping mechanism to a certain angle, so that the total height of the goods is lower than the height of the entrance door, and the control system can also be used to automatically lift and flip the goods. Specifically, after the forklift forks the goods, the control system controls the gantry to lift or controls the rotating frame to flip according to the signal state of the first sensor and the second sensor, so that the gantry 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, simplify the operation process, reduce the operation difficulty, improve the work efficiency, and have high automation degree. In addition, during the lifting of the gantry or the flipping of the rotating frame, the gantry or the rotating frame can be immediately stopped by closing the automatic control module or operating the manual operation module, so that the safety is higher. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only need to be drawn for the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0027] Figure 1 Structure diagram of the prior art in which the goods are higher than the entrance door;

[0028] Figure 2 Structure diagram of the low-space operation forklift provided by the embodiments of the present application;

[0029] Figure 3 Structure diagram of the turnover mechanism provided by the embodiments of the present application;

[0030] Figure 4 Structure diagram of the fixed frame provided by the embodiments of the present application;

[0031] Figure 5 Structure diagram of the rotating frame provided by the embodiments of the present application;

[0032] Figure 6 Structure diagram of the low-space operation forklift after picking up the goods provided by the embodiments of the present application;

[0033] Figure 7 Structure diagram of the low-space operation forklift after picking up the goods and lifting to a certain height provided by the embodiments of the present application;

[0034] Figure 8 Structure diagram of the low-space operation forklift after picking up the goods, lifting and turning over provided by the embodiments of the present application;

[0035] Figure 9 Flow chart of the control method provided by the embodiments of the present application.

[0036] In the drawings:

[0037] 1-vehicle body; 11-gantry; 2-control system; 3-turnover mechanism; 31-fixed frame; 311-connection edge; 312-parallel edge; 313-first rotating hole; 314-second rotating hole; 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 this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts 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," and "back" are based on the directions or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction. Therefore, they should not be construed as limitations on this application. Furthermore, "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed 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 with reference to the accompanying drawings and specific implementation methods.

[0041] Please refer to Figure 2 In this embodiment, a low-slung forklift is provided. The forklift includes a body 1, a tilting mechanism 3, and a control system 2. The body 1 is a conventional counterbalanced stacker truck. A liftable mast 11 is provided at the front end of the body 1. A first sensor for detecting height is mounted on the mast 11. When the mast 11 is initially retracted, i.e., when the mast 11 is lifted to a height of zero, the first sensor is in a signal-generating state. When the mast 11 begins to lift and reaches a certain height H, the first sensor maintains a signal-generating state within the mast 11 height range from zero to H. The signal-generating state of the first sensor is represented by A=1. When the mast 11 continues to lift to a height greater than H, the first sensor is in a signal-free state. The signal-free state of the first sensor is represented by A=0. It should be noted that the height H detected by the first sensor is a design value, specifically set based on the cargo size and the actual on-site entrance door height. This will not be discussed 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. The rotating frame 33 is rotatably mounted on the fixed frame 31. Thus, the lifting of the door frame 11 drives the fixed frame 31 and the rotating frame 33 to lift, thereby driving the goods on the rotating frame 33 to lift. Figure 3The fixed frame 31 is further provided with a turnover oil cylinder 32, the telescopic end of the turnover oil cylinder 32 is connected with the rotating frame 33, so as to drive the rotating frame 33 to overturn. The turnover mechanism 3 further comprises a second sensor for detecting the overturning angle of the rotating frame 33, the second sensor can be arranged on the fixed frame 31, the first sensor maintains a signal state within the rotation angle range of 0-α degrees of the rotating frame 33, and the state is recorded as C=1. When the rotating frame 33 continues to overturn, the overturning angle exceeds α degrees, the second sensor is in a signal-free state, and the state is recorded as C=0. The angle α is not randomly set, but is set according to the entrance height of the work site and the size of the goods, so as to ensure that when the rotating frame 33 rotates by α degrees, the goods can be placed at this angle and smoothly enter the entrance door.

[0043] Of course, the overturning angle range of the rotating frame 33 is limited by the inherent stroke of the turnover oil cylinder 32, and the overturning range thereof can be quantitatively described as counterclockwise rotation from the initial state of 0 degrees to the maximum of β degrees. In the rotating frame 33 defined in the initial state in the Figure 3 , the initial state is defined as the initial state when the goods are placed vertically on the rotating frame 33, and the initial state is defined as 0 degrees when the rotating frame 33 rotates counterclockwise in operation. The initial state is defined as 0 degrees, and the rotating frame 33 rotates counterclockwise to a certain angle, which is defined as α degrees. It should be noted that α degrees must be less than β degrees.

[0044] In addition, the turnover mechanism 3 further comprises necessary components such as hydraulic pipelines and electrical lines, which will not be described here, and can ensure that the above functions can be fully realized.

[0045] The control system 2 comprises an automatic control module and a manual operation module, the control system 2 is in signal connection with the first sensor and the second sensor, and in the open state of the automatic control module, the control system 2 can control the door frame 11 and the rotating frame 33 to act or stop acting according to the signal state of the first sensor and the second sensor. It should be noted that the automatic control module and the manual operation module can be two separate control systems, and the priority of the manual operation module is higher than that of the automatic control module, that is, the priority of any manual operation is higher than that of automatic operation.

[0046] The automatic control module is provided with an on / off button to start or stop the “one-key overturning” function. When the button is pressed, the automatic control module is opened, and the “one-key overturning” function is activated. The activated state is recorded as B=1. When the button is released, the “one-key overturning” function is deactivated, and the deactivation state is recorded as B=0.

[0047] It should be noted that at any time during the operation of the door frame 11 or the rotating frame 33, the automatic control module is closed or the manual operation module is operated, and the door frame 11 and the rotating frame 33 are stopped, so as to ensure that in the automatic operation process of the “one-key overturning”, any accident can be stopped in time.

[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, the control system 2 controls the door frame 11 to lift or controls the rotating frame 33 to flip according to the signal status of the first sensor and the second sensor, 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 fixed frame 31 is generally U-shaped. The connecting edge 311 of the U-shaped fixed frame 31 is equipped with a mounting hook for fixing to the mast 11. This allows for the removable tilting mechanism 3 from the mast 11. While retaining the manual operation module, after removing the tilting mechanism 3, the machine can be equipped with a forklift and used as a conventional counterbalanced stacker, achieving multiple uses. The two parallel edges 312 of the U-shaped fixed frame 31 extend away from the mast 11. 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 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 on 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, while 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 off during the process of forking and laying down, ensuring 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 extended ends of the two parallel sides 312 are provided with first rotation holes 313 for mounting the rotating frame 33. The rotating frame 33 rotates about the line connecting the two first rotation holes 313. The parallel sides 312 are also provided with second rotation holes 314 for rotatably mounting the tilting cylinder 32. The side edges 332 are provided with third rotation holes 333 corresponding to the first rotation holes 313. The side edges 332 are also provided with fourth rotation holes 334 corresponding to the second rotation holes 314. The fourth rotation holes 334 are used to mount the telescopic end of the tilting cylinder 32. Corresponding mounting holes are also provided at both ends of the tilting cylinder 32, which can be rotatably connected to the fixed frame 31 and the rotating frame 33 respectively via pins. This will not be further described 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, and can make operations simpler, safer and more efficient while greatly saving labor costs; and the base vehicle type counterbalanced stacker of the present application adopts a conventional vehicle type, and only some necessary modifications are made, which 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 applicable to the above-mentioned low-space operation forklift, comprising:

[0055] When the forklift is in operation, 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. If the first sensor is in a signal state, it is recorded as A=1, and if the first sensor is in a no-signal state, it is recorded as A=0;

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

[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 continuously flip 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 moment 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.

[0060] Please refer to Figure 9In the state that the forklift is started and the system is not faulty, it is judged whether the automatic control module is started or not. If it is started, the "one-key overturning" function is activated. If it is not started, the manual operation module is executed. The operation process under the manual operation module can be completed manually according to the traditional forklift process. Of course, before the step of judging whether the automatic control module is started or not, the forklift needs to be driven to pick up the goods in the initial state of the mast 11 and the rotary frame 33. Please refer to Figure 6 Then the "one-key overturning" function is executed.

[0061] The initial state of the mast 11 is that the lifting height of the mast 11 is zero, and the initial state of the rotary frame 33 is that the rotation angle of the rotary frame 33 is zero, that is Figure 6 In this state, overturning action cannot be performed because the goods will be scraped on the ground when overturning. Therefore, the step of lifting the mast 11 is needed. Please refer to Figure 7 The forklift is operated to lift to an appropriate height. The appropriate height is designed according to different application scenarios and different sizes of goods. The appropriate height is the lifting height H introduced above. After calculation, it can be ensured that the overturning mechanism 3 performs overturning action when being lifted to the height H or even higher. Please refer to Figure 8 At this time, the maximum diameter circular track formed by the overturning mechanism 3 is separated from the ground, and the overturning mechanism 3 and the goods will not be scraped on the ground.

[0062] In the process of automatic lifting of the mast 11 and automatic overturning of the rotary frame 33, it is designed to judge whether the "one-key overturning" function is cancelled B=0 or any manual operation is intervened, which means that in order to ensure the safety of the operation process, any manual operation intervention will terminate the automatic operation.

[0063] As can be seen from the above, the "one-key overturning" semi-automatic function can simplify the operation process, reduce the operation difficulty, and improve the work efficiency. At the same time, the priority of the manual operation function is higher than that of the "one-key overturning" semi-automatic operation function. During the execution of the "one-key overturning" function, any manual operation can terminate the automatic operation, which is safe.

[0064] It should be noted that in the present specification, relational terms such as first and second are used solely to distinguish one entity from another entity, without necessarily requiring or implying any such actual relationship or order between such entities.

[0065] The principles and implementations of the present application are described in the above examples, which are only used to help understand the method and its core idea of the present application. It should be pointed out that, for those skilled in the art, without departing from the principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A low space operation forklift, characterized in that: include: A vehicle body (1), wherein a front end of the vehicle body (1) is provided with a liftable gantry (11), and a first sensor for detecting a height change thereof is provided on the gantry (11), wherein the first sensor maintains a signal state when the gantry (11) is within a height range of zero to H, and when the lift height of the gantry (11) is greater than H, the first sensor is in a no-signal state; A turning mechanism (3) comprises a fixed frame (31) connected to the door frame (11) and a rotating frame (33) rotatably arranged on the fixed frame (31), a turning oil cylinder (32) being provided on the fixed frame (31), a telescopic end of the turning oil cylinder (32) being 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 is in a no-signal state when the rotation angle of the rotating frame (33) is greater than α degrees; A control system (2) includes 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 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 on 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 space operation forklift according to claim 2, characterized in that: The rotating frame (33) includes 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 on 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), and the rotating frame (33) rotates around the line connecting the two first rotating holes (313) as the axis. The parallel sides (312) are also provided with second rotating holes (314), and the second rotating holes (314) are used for rotatably mounting the turning cylinder (32).

5. The low-slung space operation forklift according to claim 4, characterized in that: A third rotating hole (333) corresponding to the first rotating hole (313) is provided on the side (332), and a fourth rotating hole (334) corresponding to the second rotating hole (314) is also provided on the side (332). The fourth rotating hole (334) is used to install the telescopic end of the tilting oil 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: When the forklift is in operation, 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. If the first sensor is in a signal state, it is recorded as A=1; if the first sensor is in a no-signal state, it is recorded as A=0; If A=1, the gantry (11) is controlled to continuously elevate until A=0, the gantry (11) stops elevating, and the rotating frame (33) is controlled to flip; if A=0, the rotating frame (33) is controlled to flip; Acquiring a signal state of the second sensor during the turning process of the rotating frame (33), wherein 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 moment 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, it is determined whether the automatic control module is turned on. If not, the manual operation module is executed.

8. The control method according to claim 6, characterized in that: Before the step of determining whether the automatic control module is turned on when the forklift is in operation, 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 turning mechanism (3) is separated from the ground.

Images