CN111449574A

CN111449574A - Dust box of floor sweeping machine

Info

Publication number: CN111449574A
Application number: CN202010286248.4A
Authority: CN
Inventors: 杨德重
Original assignee: Zhuichuang Technology Suzhou Co Ltd
Current assignee: Zhuichuang Technology Suzhou Co Ltd
Priority date: 2020-04-13
Filing date: 2020-04-13
Publication date: 2020-07-28

Abstract

The invention discloses a dust box of a sweeper, which comprises a box body, a dust box body and a dust collecting device, wherein the box body is positioned on a flow path of dirty air flow in the sweeper to receive the dirty air flow from the upstream of the box body; the dust exhaust port is arranged at the bottom of the box body; the bottom inner surface of the box body is provided with a flow guide surface arranged at the periphery of the dust discharge port, and at least one part of the flow guide surface has a height difference, so that dirt in the box body flows to the dust discharge port along the flow guide surface under the traction of the gravity of the dirt. The dust box of the sweeper is provided with the flow guide surface at the bottom of the sweeper, so that dirt in the box body is dragged by the gravity of the dirt box body to converge to the dust discharge port along the flow guide surface, the dust concentration and the dust removal rate are improved, and the cleaning frequency of a user is reduced.

Description

Dust box of floor sweeping machine

Technical Field

The invention relates to the field of floor sweeping machines, in particular to a dust box of a floor sweeping machine.

Background

In the field of sweeper machines, in order to reduce the trouble of frequently cleaning the sweeper dust box by a user, a central dust collecting system is arranged on a charging seat in the prior art, so that dust in the sweeper dust box can be sucked out when the sweeper is charged, and the frequency of cleaning the sweeper dust box is reduced. It is known to collect dust using various configurations of sweeper dust boxes, which typically have a dust exhaust opening therein for exhausting dust from the dust box to a central dust collection base. However, during the process of collecting dust by the sweeper dust box, the sweeper dust box in the prior art has at least the following problems:

firstly, a dust blocking sheet of a dust discharging port of the dust box is arranged in the dust box, and dead angles are generated around the dust blocking sheet, so that the dust removing rate of dust in the dust box of the sweeper is low, and a user still needs to clean the dust box at irregular time; secondly, the sucked dust is enriched in dead corners for a long time, and the probability of mildew of the dust at the dead corners due to the enrichment of dirty air at the dead corners is increased.

Accordingly, there is a need to develop a dust box of a sweeper to solve the above problems.

Disclosure of Invention

Aiming at the defects in the prior art, the invention mainly aims to provide the dust box of the sweeper, which is characterized in that the bottom of the sweeper is provided with the flow guide surface, so that dirt in the box body is converged to the dust discharge port along the flow guide surface under the traction of the gravity of the dirt in the box body, thereby improving the dust concentration and the dust discharge rate and reducing the cleaning times of a user.

Another objective of the present invention is to provide a dust box of a sweeper, which has a dust blocking sheet disposed on a cover and a cross-sectional area of an inner space of the dust box of the sweeper on a horizontal plane gradually decreasing from top to bottom, so as to reduce the generation of dead corners and reduce the probability of mildew due to dust accumulation.

To achieve the above objects and other advantages in accordance with the present invention, there is provided a sweeper dust box including:

a cassette located in a flow path of a dirty airflow within the sweeper to receive the dirty airflow upstream thereof; and

the dust exhaust port is arranged at the bottom of the box body;

the bottom inner surface of the box body is provided with a flow guide surface arranged at the periphery of the dust discharge port, and at least one part of the flow guide surface has a height difference, so that dirt in the box body flows to the dust discharge port along the flow guide surface under the traction of the gravity of the dirt.

Preferably, the flow guide surface is an inclined plane or a smooth curved surface arranged on the inner surface of the bottom of the box body.

Preferably, a fluid inlet is formed on a windward side of the box body, which is directly opposite to the dirty air flow, and a fluid outlet is formed on a position of the box body, which is opposite to the fluid inlet.

Preferably, a dust-blocking door is rotatably connected to the fluid inlet, and the dust-blocking door can rotate relative to the fluid inlet to switch the fluid inlet between a closed state and an open state;

the dust blocking cabin door and the fluid inlet are provided with a dust blocking reset component, the dust blocking reset component can generate elastic restoring force acting on the dust blocking cabin door, so that when fluid convection negative pressure does not exist between the fluid inlet and the fluid outlet, the dust blocking cabin door keeps the fluid inlet in a closed state, and when fluid convection negative pressure flowing to the fluid outlet is generated between the fluid inlet and the fluid outlet, the dust blocking cabin door rotates along an opening direction to keep the fluid inlet in an open state.

Preferably, a filter is provided at the fluid outlet.

Preferably, the dust exhaust port is rotatably connected with a dust exhaust cabin door, and the dust exhaust cabin door can rotate relative to the dust exhaust port to enable the dust exhaust port to be switched between a closed state and an open state;

the dust exhaust hatch door with dust exhaust mouth department is equipped with dust exhaust reset assembly, dust exhaust reset assembly can produce and act on the elastic restoring force of dust exhaust hatch door makes when the dust exhaust mouth with when there is not fluid convection negative pressure between the fluid outlet, the dust exhaust hatch door will the dust exhaust mouth keeps the closure state, works as the dust exhaust mouth with produce the flow direction between the fluid outlet during the fluid convection negative pressure of dust exhaust mouth, the dust exhaust hatch door is rotatory so that along an opening direction the dust exhaust mouth keeps open state.

Preferably, one side of the cartridge body is at least partially open to form a cleaning window, and a cover body is rotatably connected to the cleaning window to selectively close the cleaning window.

Preferably, the cleaning window is open on a windward side which is directly opposite to the dirty air flow, and the fluid inlet is open on the cover.

Preferably, the box body is provided with a cover body which is rotatably connected with the box body, and when the box body is in a closed state, the cover body forms an included angle of α with the inner bottom surface of the box body;

the inner side of the cover body is also provided with a clamping hook, the clamping hook protrudes out of the cross section of the cover body, and the clamping hook is matched with a fixed bulge of a top plate of the box body;

the cover body comprises a bent section and a straight section, wherein the fluid inlet is arranged on the bent section, so that the opening direction of the fluid inlet is deviated to the ground.

Preferably, the dust discharging port of the dust box protrudes out of the dust box.

Preferably, the top of the dust box of the sweeper is provided with a top plate, and the surface of the top plate facing the inside of the dust box of the sweeper is provided with at least one group of turbulence rib plates.

The turbulence rib plates are symmetrically distributed in a splayed shape and are bent into an arc shape, a turbulence channel is formed between a group of the turbulence rib plates, and the turbulence channel is gradually widened along the airflow direction.

Preferably, the cross-sectional area of the inner space of the box body on the horizontal plane is gradually reduced from top to bottom.

The technical scheme has the following advantages or beneficial effects: through being equipped with the water conservancy diversion face in the quick-witted bottom of sweeping the floor, can reduce the inside dead angle of dirt box for foul in the box body is along under its self gravity's traction the water conservancy diversion face converge extremely arrange the dirt mouth, thereby improve the concentration of dust and the efficiency of getting rid of dust, reduce user's clean number of times. In addition, the dust exhaust mouth sets up to the outside protrusion of dirt box and can further reduce the inside dead angle of dirt box, reduces the dust and concentrates the probability that appears mildening and rot, further reduces user's clean number of times. In addition, the turbulence rib plate arranged on the top plate of the dust box can further increase the disturbance of airflow inside the dust box, and the dust exhaust efficiency is improved.

Among the above-mentioned technical scheme of box body inner space, the cross sectional area of box body inner space on the horizontal plane is the trend that reduces gradually on the orientation from last down, can make the whole trend of directional dust exhaust mouth gathering of foul, improves dirt box dust exhaust efficiency.

Drawings

Fig. 1 is a top view of a proposed cassette according to an embodiment of the invention;

FIG. 2 is a cross-sectional view of a cassette taken along line B-B according to one embodiment of the present invention;

FIG. 3 is a perspective view of a partial cassette shown in a perspective view according to one embodiment of the present invention;

FIG. 3a is a perspective view of a separation device from another perspective of a cassette body according to one embodiment of the present invention;

FIG. 4 is a perspective view of a cassette according to an embodiment of the present invention;

FIG. 5 is a perspective view of a separating apparatus for a filter on a cartridge according to an embodiment of the present invention;

FIG. 6 is a schematic perspective view of another perspective view of a cassette according to an embodiment of the present invention;

fig. 7 is a schematic perspective view of another perspective view of the proposed dust exhaust door according to an embodiment of the present invention;

fig. 8 is a schematic perspective view of another perspective view of the proposed dust exhaust door according to an embodiment of the present invention;

FIG. 9 is a side cross-sectional view of a proposed cassette according to one embodiment of the invention;

FIG. 10 is a schematic perspective view of another perspective view of a cassette according to an embodiment of the present invention;

fig. 11 is a perspective view of a top plate according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

In the drawings, the shape and size may be exaggerated for clarity, and the same reference numerals will be used throughout the drawings to designate the same or similar components.

In the following description, terms such as center, thickness, height, length, front, back, rear, left, right, top, bottom, upper, lower, etc., are defined with respect to the configurations shown in the respective drawings, and in particular, "height" corresponds to a dimension from top to bottom, "width" corresponds to a dimension from left to right, "depth" corresponds to a dimension from front to rear, which are relative concepts, and thus may be varied accordingly depending on the position in which it is used, and thus these or other orientations should not be construed as limiting terms.

Terms concerning attachments, coupling and the like (e.g., "connected" and "attached") refer to a relationship wherein structures are secured or attached, either directly or indirectly, to one another through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.

According to an embodiment of the present invention, as shown in fig. 1 and 2, it can be seen that the dust box of the sweeper comprises:

an internally hollow box 21 located in the flow path of the dirty airflow within the sweeper to receive the dirty airflow upstream thereof; the at least one dust exhaust port 211 is arranged at the bottom of the box body 21, and the dust exhaust port 211 protrudes towards the outside of the dust box;

the bottom of the box body 21 is formed with a flow guide surface 216 surrounding the dust discharge port 211, at least a part of the flow guide surface 216 has a height difference, so that the dirt in the box body flows together to the dust discharge port along the flow guide surface 216 under the traction of the gravity of the dirt, and specifically, the flow guide surface is an inclined plane or a smooth curved surface on the inner surface of the bottom of the box body.

Referring now to fig. 3, it can be clearly understood that a fluid inlet 2121 is opened on the windward side of the box 21 which is directly opposite to the dirty air stream, and a fluid outlet 2131 is opened on the box 21 opposite to the fluid inlet 2121.

Referring now to FIG. 4 in conjunction with FIG. 3, a dust door 214 is pivotally attached to the fluid inlet 2121, and the dust door 214 is capable of rotating relative to the fluid inlet 2121 to switch the fluid inlet 2121 between a closed position and an open position;

further, a dust retention return element is disposed between the dust retention door 214 and the fluid inlet 2121, and the dust retention return element is capable of generating an elastic return force acting on the dust retention door 214, such that when there is no negative fluid convection pressure between the fluid inlet 2121 and the fluid outlet 2131, the dust retention door 214 maintains the fluid inlet 2121 in the closed state, and when a negative fluid convection pressure is generated between the fluid inlet 2121 and the fluid outlet 2131 and flows toward the fluid outlet 2131, the dust retention door 2131 rotates in an opening direction to maintain the fluid inlet 2121 in the open state.

In a specific embodiment, the dust door 214 is rotatably connected inside the cover 212, and the dust door 214 is disposed parallel to the fluid inlet 2121, and the width of the dust door 214 gradually increases from the rotating connection to the bottom along the inclination direction of the cover 212. When the sweeper performs cleaning, the dust outlet 211 is closed, the dust-blocking door 214 is pushed by the external air flow to move away from the cover 212, so that the dust-containing air flow moves downwards along the surface of the dust-blocking door 214 and enters the sweeper dust box, when the dust-containing air flow touches the bottom, the flow direction is deflected, the fluid inlet 2121 is provided with the dust-blocking door 214, so that the dust cannot go out from the fluid inlet 2121, air can only flow out from the filter 213, and dust is left in the sweeper dust box. When no dusty airflow enters the sweeper dust box, the dust blocking door 214 naturally covers the fluid inlet 2121, and the dust blocking door 214 ensures that the dusty airflow can only enter the sweeper dust box. Therefore, when the sweeper dust box performs a dust removing operation, the dust outlet 211 is opened, the fluid inlet 2121 is closed because the dust blocking compartment door 214 still covers the fluid inlet 2121, and the airflow enters the filter 213 and flows out of the sweeper dust box 21 through the fluid outlet 2131.

Referring now to fig. 5 in conjunction with fig. 4, it can be seen clearly that a filter 213 is provided at the fluid outlet 2131. The filter is used for filtering dust in gas, and the filter 213 includes: a first filter grill 2132 provided at the dirty air flow inlet filter 213; a second filter grill 2134 provided at the dirty air outflow filter 213; and filter cotton 2133 interposed between first filter grid 2132 and second filter grid 2134.

Further, the first and

second filter lattices

2132 and 2134 are respectively provided with at least one straight lateral side and longitudinal side, which are perpendicular to each other to form a filter lattice. The first filter grid 2132 and the second filter grid 2134 cooperate to fix the filter cotton 2133 at the fluid outlet 2131.

Further, as the dirty airflow enters the sweeper dust box 21 through the fluid inlet 2121, the airflow continues to exit the sweeper dust box 21 through the filter 213, and the dust is filtered and retained within the sweeper dust box.

Referring now to fig. 6, 7 and 8, it can be understood that a dust exhaust door 2112 is rotatably connected to the dust exhaust port 211, and the dust exhaust door 2112 can rotate relative to the dust exhaust port 211 to switch the dust exhaust port 211 between a closed state and an open state; the dust exhaust door 2112 is arc-shaped, and a reinforcing rib 21121 is arranged on the lower surface of the dust exhaust door 2112, so that the structure of the dust exhaust door 2112 is stable. The material of the dust discharge door 2112 is particularly preferably a rubber material.

Further, a dust exhaust return component is disposed at the dust exhaust port 2112 and the dust exhaust port 211, and the dust exhaust return component can generate an elastic return force acting on the dust exhaust port 2112, so that when there is no fluid convection negative pressure between the dust exhaust port 211 and the fluid outlet 2131, the dust exhaust port 2112 keeps the dust exhaust port 211 in the closed state, and when there is fluid convection negative pressure flowing to the dust exhaust port 211 generated between the dust exhaust port 211 and the fluid outlet 2131, the dust exhaust port 2112 rotates in an opening direction to keep the dust exhaust port 211 in the open state.

Further, when the space in the box body 21 is not enough, the automatic dust collecting system moving to the charging seat can generate large suction force, so that the dust exhaust door 2112 can rotate under the influence of the suction force, the dust exhaust port 211 is opened, dust is sucked into the charging seat for collecting the dust, the space of the box body 21 is emptied, reuse is facilitated, and the cleaning frequency of a user is reduced. After the dust discharging operation is completed, the dust discharging door 2112 has recovery performance due to the use of rubber material, and rotates again to recover to the original position to seal the dust discharging port 211, thereby effectively ensuring that dust cannot leak out in the box body 21.

Referring again to fig. 3a in conjunction with fig. 3, it can be seen that one side of the housing 21 is at least partially open to form a cleaning window 2123, and a cover 212 is rotatably attached to the cleaning window 2123 to selectively close the cleaning window 2123. The cleaning window 2123 is opened on a windward side which is directly opposite to the dirty air flow, and the fluid inlet 2121 is opened on the cover 212.

Further, referring to fig. 9, a cover 212 is rotatably connected to the box body 21, and particularly preferably, a lower end of the cover 212 is hinged to a bottom of the box body 21, when the box body 21 is in a closed state, the cover 212 forms an angle α with an inner bottom surface of the box body 21, particularly preferably, an angle of 120 ° to 135 °, and an anti-slip groove 215 is further formed at an upper end of the cover 212 at an interval.

Further, the cover 212 includes a curved section and a straight section, wherein the fluid inlet 2121 is disposed on the curved section, so that the opening direction of the fluid inlet 2121 is biased to the ground, and the dirty air is maximally sucked into the case 21. The fluid inlet 2121 and the fluid outlet 2131 are not parallel to each other, so that when the sweeper performs dust exhausting work, when the dust exhaust door 2112 is opened to generate negative pressure, all air flow enters from the fluid outlet 2131, and the dust blocking door 214 cannot rotate under the influence of the negative pressure, so that the fluid inlet 2121 is opened.

Further, referring to fig. 10, a fastening structure 217 is disposed on the surface of the cover 212 contacting with the sweeper. The snap structure 217 includes a snap button 2172 and a snap protrusion 2171, although not shown in the figures, it should be understood that the snap button 2172 of the snap structure 217 is provided with a spring to enable the snap protrusion 2171 to telescope within the thickness distance of the cover 212 to allow the sweeper dust box to be secured or removed.

The upper end of the filter 213 is provided with a snap groove 216, and the snap groove 216 is matched with the snap structure 217 for use.

Specifically, when the dust box needs to be cleaned, fingers are placed on the snap groove 216 and the snap button 2172, respectively, so that the snap protrusion 2171 retracts inward; the dust box of the sweeper is held by hand and pulled upwards, and the dust box is removed out of the sweeper. When the sweeper dust box is removed from the sweeper, the fingers push the cover 212 in a direction away from the box body 21, the cover 212 can be opened, the dust blocking cabin door 214 can also remove the box body 21 along with the cover 212, a user can easily clean dust and dirt in the box body 21, the dust blocking cabin door 214 can also be cleaned more effectively, and the phenomenon that the dust in the dead angle in the box body 21 is accumulated and mildewed is avoided.

Referring to fig. 9 again, it can be clearly understood that the inner side of the cover 212 is further provided with a hook 2122, the hook 2122 protrudes out of the cross section of the cover 212, and the hook 2122 is matched with the fixing protrusion 2183 of the top plate 218 of the box body 21. The cross-sectional area of the end of the hook 2122 is decreasing from bottom to top, and this structure enables the fixing protrusion 2183 to move along the contour of the hook 2122 when the fixing protrusion is used in cooperation, so as to enable the fixing protrusion 2183 to be buckled with or separated from the hook 2122, further limiting the position of the cover 212 and the box 21, and further enhancing the fixing of the cover 212.

Referring now to fig. 11, a top plate 218 is provided on the top of the box body 21, and at least one set of baffle 2181 is provided on the surface of the top plate 218 facing the inside of the box body 21.

Further, the spoiler ribs 2181 are distributed in a splayed symmetrical manner and are bent into an arc shape, wherein the cross-sectional area of the spoiler ribs 2181 is gradually increased along the airflow direction. When the dust-containing airflow enters from the fluid inlet 2121, the direction of the collision rear part is changed, the upward airflow slowly flows to the bottom of the sweeper dust box along the turbulence rib plate 2181 after contacting the top plate 218, so that the dust sinks to the bottom due to the weight, the airflow flows along the wall of the sweeper dust box, and the dust in the sweeper dust box is prevented from being disturbed by the internal airflow.

Referring now again to fig. 9, it can be seen that the cross-sectional area of the box 21 in the horizontal plane is gradually reduced from the top to the bottom. Make the dust in the box body 21 receive the air current disturbance after, rely on self gravity to slide down to dust exhaust port 211 gradually, especially the effect of large granule heavy object is better, can roll to dust exhaust port 211 along the slope to further play the effect that promotes box body 21 net empty rate.

Further, the whole part that contacts with the robot of sweeping the floor of box body 21 is equivalent to the wedging structure, when the robot of sweeping the floor is put into to box body 21, because the cross sectional area of the inner space of box body 21 on the horizontal plane is the trend that reduces gradually on the orientation down from the top, under the influence that receives gravity, box body 21 can be more with the inside in close contact with of the robot of sweeping the floor inside the robot of sweeping the floor, and is more stable firm. The cross-sectional area of box body 21 on the horizontal plane is the trend of dwindling gradually on the direction from the top down and can also make box body 21 when taking out, reduces gradually and sweeps the inside contact of robot, reduces the friction, conveniently takes out box body 21 smoothly from the top of sweeping the robot.

Various modifications may be made to the inventive concept by those skilled in the art without departing from the scope of the invention as defined in the appended claims. For example, the number of fluid inlets 2121 of the case 21 is increased to cover the dead space.

The number of apparatuses and the scale of the process described herein are intended to simplify the description of the present invention. Applications, modifications and variations of the present invention will be apparent to those skilled in the art.

While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.

Claims

1. The utility model provides a quick-witted dirt box of sweeping floor which characterized in that includes:

a cassette (21) located in the flow path of the dirty airflow within the sweeper to receive the dirty airflow from upstream thereof; and

at least one dust exhaust port (211) arranged at the bottom of the box body (21);

the inner surface of the bottom of the box body (21) is provided with a flow guide surface (216) arranged on the periphery of the dust outlet (211), and at least one part of the flow guide surface (216) has a height difference, so that dirt in the box body (21) can be converged to the dust outlet (211) along the flow guide surface (216) under the traction of the gravity of the dirt.

2. The sweeper dust box of claim 1, wherein the deflector surface (216) is an inclined plane or a smooth curved surface disposed on the inner surface of the bottom of the box body.

3. The sweeper dust box of claim 1, wherein a fluid inlet (2121) is provided on a windward side of the box (21) which is directly opposite to the dirty air stream, and a fluid outlet (2131) is provided on the box (21) opposite to the fluid inlet (2121).

4. The sweeper dust box of claim 3, wherein a dust barrier door (214) is rotatably connected to the fluid inlet (2121), the dust barrier door (214) being rotatable relative to the fluid inlet (2121) to switch the fluid inlet (2121) between a closed state and an open state;

a dust retention return member is disposed between the dust retention door (214) and the fluid inlet (2121), the dust retention return member being capable of generating a resilient return force acting on the dust retention door (214) such that when a fluid convective negative pressure is not present between the fluid inlet (2121) and the fluid outlet (2131), the dust retention door (214) maintains the fluid inlet (2121) in the closed state, and when a fluid convective negative pressure is generated between the fluid inlet (2121) and the fluid outlet (2131) to the fluid outlet (2131), the dust retention door (214) rotates in an opening direction such that the fluid inlet (2121) is maintained in the open state.

5. The sweeper dust box of claim 4, wherein a filter (213) is provided at the fluid outlet.

6. The sweeper dust box of claim 3, wherein a dust exhaust door (2112) is rotatably connected to the dust exhaust port, and the dust exhaust door can rotate relative to the dust exhaust port (211) to switch the dust exhaust port (211) between a closed state and an open state;

the dust exhaust device is characterized in that a dust exhaust reset component is arranged at the position of the dust exhaust port door (2112) and the dust exhaust opening (211), the dust exhaust reset component can generate elastic restoring force acting on the dust exhaust port door, so that when fluid convection negative pressure does not exist between the dust exhaust opening (211) and the fluid outlet (2131), the dust exhaust port door (2112) keeps the dust exhaust opening (211) in a closed state, and when fluid convection negative pressure flowing to the dust exhaust opening (211) is generated between the dust exhaust opening (211) and the fluid outlet (2131), the dust exhaust port door (2112) rotates in an opening direction to keep the dust exhaust opening (211) in an open state.

7. The sweeper dust box of claim 3, characterized in that one side of the box body (21) is at least partially open to form a cleaning window (2123), and a cover (212) is rotatably attached to the cleaning window (2123) to selectively close the cleaning window (2123).

8. The sweeper dust box of claim 7, characterized in that the box body (21) is provided with a cover body (212) rotatably connected therewith, and when the box body (21) is in a closed state, the cover body (212) forms an angle α with the inner bottom surface of the box body (21);

the cover body (212) comprises a bent section and a straight section, wherein the fluid inlet (2121) is arranged on the bent section, so that the opening direction of the fluid inlet (2121) is biased to the ground.

9. The sweeper dust box of claim 1, wherein a top plate (218) is disposed on the top of the sweeper dust box, and at least one set of spoiler ribs (2181) is disposed on a surface of the top plate (218) facing the interior of the sweeper dust box.

10. The sweeper dust box of claim 1, wherein the cross-sectional area of the internal space of the box body (21) in the horizontal plane is gradually reduced from top to bottom.