CN111497041A - Stone plate unloading machine and plate unloading method - Google Patents

Abstract

The invention provides a stone unloader, which comprises a transport trolley, a steel rail system, a working device and a plate removing device, wherein the transport trolley is arranged on the transport trolley; the working device comprises a stone slab bottom chiseling mechanism, a stone slab breaking mechanism and a first stone slab suction cup. The invention also provides an automatic stone plate unloading method, which can realize mechanized stone plate unloading operation, support full-automatic control and have high working efficiency, and fundamentally ensure the personal safety of workers.

Description

Stone unloading machine and unloading method

technical field

The invention relates to a stone slab unloading machine and a slab unloading method.

Background technique

In the production process of natural slate, it is necessary to cut the rubble that has been processed into a relatively square shape, cut the rubble into pieces of slate, and the lower ends of these slates are still connected, and then transported to the unloading place for unloading. The process of unloading the slabs includes: breaking the slabs from the lower end by manual tools, then lifting the slabs and transporting them to the storage position. This work process requires workers to perform meritorious work. It is not only heavy physical work but also very dangerous. It is easy to cause injury accidents during the process of breaking the slate, supporting and lifting the slate, and the dust at the work site is large, which is not good for human health.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a stone slab unloading machine, which can realize mechanical stone slab unloading, improve production efficiency, and protect workers from the danger of manual slab unloading. For this reason, the present invention adopts the following technical solutions:

The stone unloading machine is characterized in that it includes a transport trolley and a rail system, a working device and a plate removing device;

The working device includes a slate bottom chisel mechanism, a slate breaking mechanism and a first slate suction cup;

The slate bottom chisel mechanism is arranged in front of the lower end of the slate that is transported to the slate treatment position on the trolley corresponding to the transport of the stone material, and is used to treat the lower end of the erected slate in the treatment position and the lower end of the stone base plate to be easily broken. connect;

The slate breaking mechanism is used for pushing the slate processed for easy breaking backwards and breaking it from the lower end;

The first slate suction cup is arranged to correspond to the upright slate in the processing position, and is installed telescopically, and the installation frame is connected with the first transfer mechanism;

The transport trolley and the rail system are used to transport the frontmost slate of the stone material to the front of the first slate suction cup and make the frontmost slate on the transporting stone trolley press the direction of the first slate suction cup from the front;

The slate removal device is provided with a second slate suction cup and a second transfer mechanism, the mounting frame of the second slate suction cup is installed on the second transfer mechanism, and the first transfer mechanism cooperates with the slate removal device to lift the second slate suction cup. The slate that is broken from the lower end absorbed by a slate suction cup is transferred to a position where it can be sucked by the second slate suction cup on the slate removal device.

On the basis of adopting the above-mentioned technical solutions, the present invention can also adopt the following further technical solutions, or use these further technical solutions in combination:

The bottom chisel mechanism includes several pneumatic picks or small cutting machines arranged in a row, and the pneumatic picks are arranged in an oblique downward direction.

The back of the first slate suction cup is provided with a spring; the first slate suction cup is supported by the spring, and the farthest extended position of the first slate suction cup satisfies that the slate when it is broken backward can also be sucked by the first slate suction cup .

The slate breaking mechanism is arranged in front of the processing position.

The first transfer mechanism includes a hingedly mounted rotating arm, the mounting frame of the first slate suction cup is connected with the rotating arm, and the mounting frame or the rotating arm is also rotatably connected with a hingedly mounted oil cylinder to be pulled by the oil cylinder. Rotation, the axis of rotation is a horizontal axis.

The first transfer mechanism is a linear conveying device, which includes a lifting mechanism, or further includes a forward-backward moving mechanism or/and a left-right moving mechanism.

The trolley for transporting the stone is provided with a plurality of stone supporting and adjusting oil cylinders, so as to support the stone and adjust the level of the stone.

The stone transport trolley is provided with a motor to drive the transport trolley to move on the steel rail, and the trolley is parked when the motor stops working.

The stone unloading machine is provided with a control device and a sensor, the sensor is connected with the control device, the sensor includes a first sensor, and the first sensor is used to sense that the frontmost stone slab on the trolley for transporting the stone arrives at the processing position; the The electric motor of the trolley for transporting the stone, the power of the bottom chisel mechanism, the gas path of the first slate suction cup, the power of the slate breaking mechanism, and the power in the first transfer mechanism are all controlled by the control device.

Another technical problem to be solved by the present invention is to provide an automatic unloading method for slate, which improves production efficiency and protects workers from the danger of manual unloading. For this reason, the present invention adopts the following technical solutions:

An automatic unloading method for slate, characterized in that it comprises the following steps:

(1) The transport trolley and the rail system transport the stone to the frontmost stone slab to the processing position, and the lower ends of the stone slab are all connected to the stone bottom plate; the control device controls the transport trolley to stop according to the signal of the sensor; When the frontmost slate reaches the processing position, the retractable first slate suction cup is compressed;

(2) Controlled by the control device, the slate bottom chisel mechanism works, and the lower end of the connection between the slate at the processing position and its stone floor is treated as a weak connection that is easy to break;

(3) Controlled by the control device, the slate breaking mechanism works, pushes the slate in the processing position backward, and breaks it from the lower end connected with the stone substrate. During the pushback process, the retractable first slate suction cup is stretched forward , sucks the broken stone slab;

(4) Lift the first slate sucker, and transfer the sucked slate to a position where the second slate sucker in the slate removal device can suck it;

(5) The second slate suction cup in the slate removal device sucks the slate, and the second transfer mechanism in the slate removal device transfers the slate to the unloading position;

(6) Repeat steps (1) to (5).

Due to the adoption of the technical scheme of the present invention, the mechanized plate unloading operation can be realized, and the automatic control can be supported, the work efficiency is high, and the personal safety of the workers is fundamentally guaranteed.

Description of drawings

FIG. 1 is a schematic diagram of Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of another angle of Embodiment 1 of the present invention.

FIG. 3 is a side view of Embodiment 1 of the present invention.

FIG. 4 is one of the demo diagrams for unloading the plate according to the first embodiment of the present invention. At this time, the bottom chisel mechanism is working.

FIG. 5 is the second demo diagram of the unloading of the first embodiment of the present invention. At this time, the mounting frame of the first slate suction cup is driven to rotate to a horizontal position by the first transfer mechanism, waiting for the slate removing device to descend and take the plate.

FIG. 6 is a schematic diagram of Embodiment 2 of the present invention.

FIG. 7 is a schematic diagram of another angle of Embodiment 2 of the present invention.

FIG. 8 is a side view of Embodiment 2 of the present invention.

FIG. 9 is one of the demo diagrams of the unloading of the second embodiment of the present invention. At this time, the slate removing device is removing the slate that it has adsorbed, and the mounting frame of the first slate suction cup has just dropped in place, and is ready to carry out the next slate. Work.

Fig. 10 is the second demonstration diagram of unloading of the second embodiment of the present invention. At this time, the slate on the slate transport trolley has been unloaded, and the slate removing device is removing the last piece of slate that it adsorbs.

Detailed ways

Embodiment 1, with reference to accompanying drawings 1-5.

The stone unloading machine provided by the invention includes a transport trolley and a rail system, a working device and a plate removing device.

The working device includes a slate bottom chisel mechanism, a slate breaking mechanism and a first slate suction cup 3 .

The slate bottom chisel mechanism is arranged in front of the lower end of the slate 101 that is transported to the slate treatment position on the trolley 1 for transporting the stone material, and is used for processing the lower end 103 of the slate 101 in the treatment position and the lower end 103 connected with its stone base plate 102 for convenience. Broken weak connection.

The slate breaking mechanism is used to push the slate 101 processed for easy breaking backwards to break from the lower end 103 .

The first slate suction cup is set to be able to correspond to the upright slate 101 in the processing position. The first slate suction cup 3 is installed telescopically, and its mounting frame 30 is connected with the first transfer mechanism. The direction is consistent with the front and rear expansion and contraction directions of the first slate suction cup;

The slate removal device is provided with a second slate suction cup 4 and a second transfer mechanism, the second slate suction cup is mounted on the second transfer mechanism, and the first transfer mechanism cooperates with the slate removal device to lift the first slate The slate 101 broken from the lower end sucked by the suction cup 3 is transferred to a position where it can be sucked by the second slate suction cup 4 on the slate removing device.

The trolley 1 for transporting stone includes a frame 10, the frame 10 is connected with a steel wheel 11 as a walking mechanism, and the steel wheel 11 cooperates with the steel rail 2, which can accurately and stably determine the support reference height of the trolley to the stone, which is convenient for the following stone support adjustment oil cylinder 12. Carry out the leveling and support of the stone, and at the same time, the bottom chisel mechanism of the stone slab can always be aligned with the lower end 103 of the stone slab 101 in the processing position, so as to improve the processing effect, so that the stone can be broken neatly.

As for the transport trolley and the rail system, it can only include one rail 2 aligned with the first slab suction cup 3 and the bottom chisel mechanism and the trolley 1 for transporting stone passing on it. 1, the above-mentioned steel rail 2 is arranged on the transport trolley 13, the steel rail 2, the transport trolley 13 and the stone transport trolley 1 are used as a unit, and the steel rail 20 perpendicular to the steel rail 2 is laid on the ground, and the transport trolley 13 The frame is connected to the steel wheel 15 as a walking mechanism on the steel rail 20, and a number of the above-mentioned units are arranged on the steel rail 20, so as to facilitate the removal of the trolley after unloading the slate.

The trolley 1 for transporting the stone is provided with four stone supporting and adjusting oil cylinders 12 to support the stone and adjust the level of the stone. The stone supporting and adjusting oil cylinders 12 are arranged at the positions corresponding to the four corners of the stone, and can adopt a structure such as a jack, which can adjust the height of the top of the stone, thereby adjusting the levelness of the stone, so that the stone plate connected to the stone bottom plate 102 is in the position. Straight and vertical state, in order to improve the bottom chisel effect, the reliability of suction cup adsorption, improve the processing effect and safety.

The stone transport trolley 1 is a powered trolley, which can be driven by power to move on the rail 2. It can be powered by the motor 14 arranged on the frame 10. The motor 14 is connected with the steel wheel through the worm gear mechanism. When the motor stops , it will automatically play the parking effect. The electric motor can also be connected to the steel wheel through a gear connection mechanism, and the slate transport trolley can also be provided with a separate parking structure, which can stop when the frontmost slate (ie slate 101 ) of the stone carried by it reaches the processing position. Do not move.

The bottom chisel mechanism preferably adopts several pneumatic picks 5 arranged in a row, and can also use several small cutting machines for cutting. The air pick 5 is arranged in an oblique downward direction. When the frontmost slate (ie slate 101 ) of the stone it carries reaches the processing position, the air pick 5 or the cutting machine works to cut out a row of holes at the lower end 103 connecting the slate 101 and the bottom plate 102 of the stone, so that the connection becomes more variable. Capable of breaking for weakness, while still being able to maintain a temporary connection before breaking. Using several air picks 5 or the bottom chisel mechanism of a small cutting machine, the structure is simpler, the working speed is faster, and the weak processing can be completed in one operation. The bottom chisel mechanism can also use other tools capable of punching, drilling and cutting grooves on the stone, and is driven by the connecting mechanism to grind a groove or several weak connection positions on the stone slab.

The back of the first slate suction cup 3 is provided with a spring 31, and the first slate suction cup 3 is supported by the spring 31, and the farthest position of its extension satisfies that the slate when it is broken backwards can also be removed by the first slate suction cup 3. Slate sucker sucks. The first slate suction cup 3 can be connected to a sliding shaft, and the sliding shaft is slidably connected to the guide sleeve 32, and the guide sleeve 32 is fixed on the mounting frame 30. When approaching the processing position, the slate contacts the front of the first slate suction cup 3. As the slate continues to move forward, the first slate suction cup 3 is pressed backward and the spring 31 is compressed until the slate reaches the processing position.

The stone slab breaking mechanism is arranged in front of the processing position, and can be driven by a driving mechanism such as an air cylinder, an electric motor, an oil cylinder, etc., and the execution component is a working head 6 or an arm that pushes the stone slab, and the working head 6 or the arm can be a number of Each of them is connected with their respective driving mechanisms, and one driving mechanism can also be connected with several working heads or arms. The slate breaking mechanism is preferably located at the position corresponding to the upper part of the slate, so that it can be arranged above the first slate suction cup 3, which can avoid the work interference with the first slate suction cup 3 and the slate bottom chisel mechanism, and at the same time can increase the breaking rate. The working arm of the slate can reduce the weight and power requirements of the slate breaking mechanism. Under this setting condition, the power of the slate breaking mechanism can be selected from the cylinder 61, which is not only light in weight but also works fast. The slate breaking mechanism can be installed on the mounting frame 30 of the first slate suction cup 3 . The slate undercut mechanism can also be installed on the mounting frame 30 .

The stone plate breaking mechanism can be set directly in front of the processing position as described above, or can be set in front of the side, and the working head or arm of the stone plate is driven by the corresponding mechanical arm to reach the stone plate position.

When the slate breaking mechanism pushes the slate 101 backward, as the slate 101 leans back, the previously compressed spring 31 releases energy, and the first slate suction cup 3 stretches forward as the slate 101 leans back, sucking the broken Slate 101 at the time.

The first transfer mechanism includes a rotating arm 71, which is hingedly connected with the fixed arm 72, the fixed arm 72 is fixedly mounted on the fixed frame 7, and the mounting frame 30 of the first slate suction cup 3 is connected with the rotating arm 71. The mounting frame 30 is also rotatably connected to the hingedly mounted oil cylinder 73, the oil cylinder 73 is rotatably connected to the fixing frame 7, and the rotating shaft is a horizontal shaft. With this structure, the speed of transferring the stone slabs is fast and safe. The mounting frame 30 and the rotating arm 71 are rotated upward to a horizontal position under the pulling of the oil cylinder 73 , and after the slate sucked by them is handed over to the slate removal device, they are then pushed downward by the oil cylinder 73 to the initial position. position and work on the next slate.

The slate removal device is located above the above working device, the second slate suction cup 4 is also installed telescopically like the first slate suction cup 1 , and its mounting frame 40 is connected with the second transfer mechanism, and the second slate suction cup 4 In the downward direction, the second slate suction cup 4 can be connected with a sliding shaft, the sliding shaft is slidably connected with the guide sleeve, the guide sleeve is fixed on the mounting frame 40, the back of the second slate suction cup 4 is provided with a spring 41, the said Under the support of the spring 41, the second slate suction cup 4 is in elastic buffer contact with the slate to be unloaded, which can absorb errors and protect the structure.

In this embodiment, the second transfer mechanism includes a lifting mechanism 42 and a horizontal translation structure 43, the mounting frame 40 is connected to the lifting structure 42, the lifting structure 42 is connected to the horizontal translation structure, and the horizontal translation structure can be a chain or pulley device. The lifting mechanism can also be a moving structure driven by a chain, a pulley device, etc., or a rack and pinion structure driven by a motor, etc.

The stone unloading machine is provided with a control device and a sensor, and the control device can mainly be a single chip microcomputer and several relays. The sensor includes a first sensor 81, the first sensor 81 is connected to the control device, and the first sensor is used to sense that the frontmost stone slab 101 on the trolley 1 for transporting the stone arrives at the processing position, so that the control device controls the transportation of the stone according to the signal. The trolley 1 stops, controls the bottom chisel mechanism, the slate breaking mechanism, and the first slate suction cup to work, controls the power of the first transfer mechanism to work, and controls the slate transport trolley 1 to move forward after the slate 101 is transferred to the slate removal device, and the above can be controlled according to the sequence. The first sensor 81 can be installed at the first slate suction cup, such as behind it, and the first sensor 81 can be a proximity switch. When the first slate suction cup 3 is pressed back by the frontmost slate of the stone carried by the slate transport trolley 1, it can move backward. The first sensor 81 is triggered to send out a signal. When the slab 101 is transferred to the slab removing device, the first slab suction cup 3 moves forward by the pushing force of the spring 41, and the first sensor 81 sends out a signal again. The motor 14 of the stone transport trolley 1, the power of the bottom chisel mechanism (such as the gas circuit electromagnetic switch), the gas circuit of the first slate suction cup (such as the gas circuit electromagnetic switch), and the power of the slate breaking mechanism (such as the gas circuit electromagnetic switch) , The power in the first transfer mechanism (such as the electromagnetic switch of the oil circuit) is controlled by the control device, which can realize the fully automatic mechanized plate removal when the plate is unloaded.

A sensor can also be provided for the first transfer mechanism, and the sensor is connected to the control device. When the first transfer mechanism transfers the slate or the suction cup of the first slate is in place, according to the control of the control device, the work of the first transfer mechanism is stopped, and the removal of the slate is started. The work of the device or the work of the stone transport trolley can also be controlled by the control device according to the time sequence control according to the signal of the first sensor.

For the slate removal device, a second sensor 82 can also be provided, and the slate removal device can be controlled by the above-mentioned control device or by its own control device. The second sensor 82 is connected to the control device, the second sensor is used to sense that the second slate suction cup 4 has received the slate being unloaded, and it can also be installed behind the second slate suction cup like the first sensor is installed . The control device controls the second slate suction cup 4 to work, and controls the power of the second transfer mechanism to work. A sensor can also be provided for the second transfer mechanism. The sensor is connected to the control device and is controlled to perform corresponding work. This control may also be performed by the control device according to the timing control based on the signal of the second sensor.

Embodiment 2, referring to Figures 6-10.

In this embodiment, the bottom chisel mechanism is not installed on the installation frame 30, and is not lifted with the first slate suction cup, but is installed on its installation bracket 50, and the installation bracket 50 is directly fixed on the fixing frame 7 superior.

In addition, the first transfer mechanism is a linear motion mechanism, including the lifting mechanism 74, the mounting frame 30 is mounted on the lifting mechanism 74, and the mounting frame of the second working suction cup 4 in the stone slab removing device is a rotatable When receiving the slate, it is in the vertical state as shown in Figure 1, and when the slate is put down, it is driven by the motor and turned to be horizontal. The elevating mechanism 74 can be driven up and down by a pulley device 75 . If necessary, the up-and-down mechanism 74 can be connected to the forward and backward movement or/and the left and right movement mechanisms. At this time, the mounting frame 30 is connected to the forward and backward movement or/and the left and right movement mechanisms.

Correspondingly, in Embodiment 2, the sensor can be installed as in Embodiment 1 and controlled by the controller.

As for the transport trolley and the rail system, the functions of the upper and lower layers are just interchanged compared with the first embodiment. The rail 20a laid on the ground is aligned with the first slab suction cup 3 and the bottom chisel mechanism. On the vertical steel rail 2a of 20a, the steel rail 2a is arranged on the transport trolley 13a on the steel rail 20a, and a plurality of stone transport trolleys 1 can run on the steel rail 2a.

In this embodiment, other parts are the same as those in Embodiment 1. In Figs. 6-10, the reference numerals are the same as those in Figs. 1-5, representing the same meaning.

The stone slab unloading machine of the present invention can use the following methods to automatically unload slabs:

(1) The transport trolley and the rail system transport the stone to the frontmost stone slab 101 to the processing position, and the lower ends of the stone slab are all connected to the stone base plate 102; the control device controls the stone transport trolley 1 according to the signal of the sensor Stop; the processing position is the position where the slate bottom chisel mechanism and the slate breaking mechanism can process the slate, and when the frontmost slate 101 reaches the processing position, the retractable first slate suction cup 3 is compressed;

(2) Controlled by the control device, the slate bottom chisel mechanism works, and the lower end 103 connecting the slate 101 at the processing position and its stone base 102 is treated as a weak connection that is easy to break;

(3) Controlled by the control device, the slate breaking mechanism works, pushes back the slate 101 in the processing position, and breaks it from the lower end 103 connected to the stone substrate 102. During the push-back process, the retractable first slate suction cup 3 It is stretched forward to catch the broken stone slab;

(4) Lift the first slate sucker 3, and transfer the sucked slate to a position where the second slate sucker 4 in the slate removal device can suck it;

(5) The second slate suction cup 4 in the slate removal device sucks the slate, and the second transfer mechanism in the slate removal device transfers the slate to the unloading position;

(6) Repeat steps (1) to (5).

The above are only specific embodiments of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the field of the present invention are all included in the protection scope of the present invention. among.

Claims (10)

1. The stone unloader is characterized by comprising a transport trolley, a steel rail system, a working device and a plate removing device;

the working device comprises a stone slab bottom chiseling mechanism, a stone slab breaking mechanism and a first stone slab sucker;

the stone slab bottom chiseling mechanism is arranged in front of the lower end of a stone slab conveyed to a stone slab processing position on the trolley corresponding to the transported stone, and is used for processing the lower end of the vertical stone slab at the processing position connected with the stone bottom plate of the stone slab to form weak connection which is convenient to break;

the stone plate breaking mechanism is used for pushing back the stone plate which is processed to be broken conveniently and breaking the stone plate from the lower end;

the first stone plate suction cup is arranged to be a vertical stone plate which can be positioned at the treatment position correspondingly at the front side and is telescopically arranged, and an installation frame of the first stone plate suction cup is connected with the first transfer mechanism;

the transport trolley and the steel rail system are used for transporting the front stone slab of the stone to the front surface of the first stone slab suction cup and enabling the front stone slab on the stone transport trolley to press the direction of the first stone slab suction cup from the front surface;

the stone slab removing device is provided with a second stone slab sucking disc and a second transfer mechanism, a mounting frame of the second stone slab sucking disc is mounted on the second transfer mechanism, and the first transfer mechanism is matched with the stone slab removing device, so that the stone slab sucked by the first stone slab sucking disc and broken from the lower end can be lifted, and the stone slab can be transferred to the position sucked by the second stone slab sucking disc on the stone slab removing device.

2. A stone unloader as claimed in claim 1, wherein the floor chisel mechanism includes a plurality of air picks or mini cutters arranged in a row, the air picks being arranged in a diagonally downward direction.

3. A stone unloader as claimed in claim 1, wherein a spring is provided behind the first stone plate suction cup; the first stone plate sucking disc is supported by the spring, and the furthest extending position of the first stone plate sucking disc meets the requirement that the stone plate when being broken backwards can be sucked by the first stone plate sucking disc.

4. A stone unloader as claimed in claim 1, wherein the stone slab breaking mechanism is disposed in front of the treatment station.

5. A stone unloader as claimed in claim 1, wherein the first transfer mechanism comprises a pivotally mounted rotatable arm, the mounting bracket of the first stone slab suction cup being connected to the rotatable arm, the mounting bracket or rotatable arm further being pivotally connected to a pivotally mounted cylinder for rotation by being pulled by the cylinder, the axis of rotation being a horizontal axis.

6. A stone unloader as claimed in claim 1, wherein the first transfer mechanism is a linear conveyor including a lifting mechanism, or further including a front and rear moving mechanism and/or a left and right moving mechanism.

7. A stone unloader as claimed in claim 1, wherein the stone carriage is provided with a plurality of stone support adjustment cylinders to support and level the stone.

8. A stone unloader as claimed in claim 1, wherein the stone carriage is provided with a motor to drive the carriage on the rails, the carriage being parked when the motor is deactivated.

9. A stone unloader as claimed in claim 1, wherein the stone unloader is provided with a control means and a sensor, the sensor being connected to the control means, the sensor comprising a first sensor for sensing arrival of a leading stone slab on a cart for transporting stone material at a processing station; the motor of the trolley for transporting the stone, the power of the bottom chiseling mechanism, the gas circuit of the first stone plate sucking disc, the power of the stone plate breaking mechanism and the power of the first transfer mechanism are all controlled by the control device.

10. An automatic stone slab unloading method is characterized by comprising the following steps:

(1) the stone is transported to the front stone slab to a treatment position by the transport trolley and the steel rail system, and the lower end of the stone slab is completely connected to the stone bottom plate; the control device controls the transport trolley to stop according to the signal of the sensor; when the front-most slate reaches the treatment site, the first retractable slate suction cups are compressed;

(2) the lower end of the connection between the stone slab and the stone bottom plate of the processing position is processed into a weak connection which is convenient to break;

(3) the stone plate breaking mechanism is controlled by the control device to work, the stone plate at the processing position is pushed backwards and broken from the lower end connected with the stone base plate, and in the process of pushing backwards, the first telescopic stone plate suction cup is extended forwards to suck the broken stone plate;

(4) lifting the first stone slab suction cups and transferring the stone slabs sucked by the first stone slab suction cups to a position in the stone slab removing device where the second stone slab suction cups can suck the stone slabs;

(5) a second stone suction cup in the stone plate removing device sucks the stone plate and transfers the stone plate to a plate unloading position by a second transfer mechanism in the stone plate removing device;

(6) and (5) repeating the steps (1) to (5).

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