Rock ballast recovery device for vertical shaft excavation construction

Abstract

The utility model provides a rock ballast recovery device for vertical shaft excavation construction. The rock ballast recovery device comprises a recovery box, two material guide plates, two supporting plates and a screen. The recycling box is provided with a feeding port, two upper discharging ports and a lower discharging port. The two material guiding plates are arranged in the recycling box, and each material guiding plate obliquely extends upwards from the lower edge of the corresponding upper discharging opening. The two supporting plates are inserted into the two upper discharging ports in a sliding mode correspondingly, and an elastic reset piece is arranged between each supporting plate and the recycling box so that the supporting plates can be driven to be inserted into and abut against the material guiding plate, and therefore the supporting plates and the material guiding plate are matched to seal the upper discharging ports. The screen is arranged in the recycling box in a sliding mode in the axial direction of the upper discharging opening, located on the upper side of the supporting plate and in transmission connection with a linear driving component used for driving the screen to move. According to the rock ballast recycling device for vertical shaft excavation construction, it can be guaranteed that rock ballast is rapidly classified and discharged, the problem that excessive rock ballast exists on the screen and consequently screen holes are blocked is solved, and therefore the rock ballast recycling operation efficiency is guaranteed.

Description

Technical Field

[0001] This application belongs to the field of resource recycling technology, specifically relating to a stone slag recycling device for vertical shaft excavation. Background Technology

[0002] Shaft excavation construction refers to the engineering construction process of vertically excavating a shaft downwards in a specific location, such as underground or in a mountain, according to design requirements. It is commonly used in fields such as mining, urban subway construction, and water conservancy projects. During the construction phase, the shaft opening must first be treated, and then an appropriate method is selected based on the geological conditions to excavate the shaft, while supporting measures are implemented to ensure the stability of the shaft. The excavated rock and debris must be removed and hoisted in a timely manner, and finally, the shaft lining is completed to enhance its structural strength and waterproof performance.

[0003] To reduce resource waste and lower project costs, construction companies typically recycle stone chips. The current recycling method involves pouring the stone chips into a storage box and using a sieve in the storage box to screen them, classifying the stone chips into fine-grained stones that fall to the bottom of the sieve and coarse-grained stones that remain on the sieve.

[0004] The inventors discovered that during the stone slag sorting and recycling process, coarse-sized stone slag accumulated on the upper part of the screen cannot be discharged in time, which easily clogs the screen holes and reduces the stone slag screening efficiency. At the same time, a large amount of stone slag accumulating on the screen not only affects the vibration of the screen (to cooperate with the feeding), but also easily leads to screen damage, reducing the efficiency of stone slag recycling. Utility Model Content

[0005] This application provides a stone slag recycling device for vertical shaft excavation, which aims to ensure that stone slag can be quickly classified and discharged to avoid excessive stone slag on the screen and causing screen hole blockage, thereby ensuring the efficiency of stone slag recycling.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0007] A stone debris recovery device for vertical shaft excavation is provided, comprising:

[0008] The recycling bin has a hollow internal structure; the upper side of the recycling bin has a feed inlet, and the outer side has two coaxially arranged upper discharge outlets, as well as a lower discharge outlet located below the upper discharge outlets;

[0009] Two guide plates are installed inside the recycling bin and correspond to the two upper discharge ports; the guide plates extend upward from the lower edge of the corresponding upper discharge ports and are inclined toward the inside of the recycling bin.

[0010] Two support plates are slidably inserted into the two upper discharge ports, and each support plate has an elastic reset element between itself and the recycling box, which is suitable for driving the support plate to insert and abut against the guide plate, thereby cooperating to close the upper discharge port; and

[0011] A screen is slidably disposed inside the recycling bin along the axial direction of the upper discharge port, located on the upper side of the support plate, and the screen is connected to a linear drive component.

[0012] In one possible implementation, the inner wall of the upper discharge port has a protrusion, the support plate is slidably disposed between the protrusion and the inner top surface of the upper discharge port, and the support plate has a bent portion adapted to abut against the protrusion.

[0013] When the support plate slides to abut against the guide plate, the bent portion abuts against the protrusion.

[0014] In one possible implementation, the resilient reset element includes:

[0015] A guide rod, fixedly connected to the protrusion, extends axially away from the recycling bin along the upper discharge port and is slidably connected to the bent portion; and

[0016] A spring is sleeved on the outer periphery of the guide rod, with one end connected to the extension end of the guide rod and the other end of the spring connected to the bent portion;

[0017] When the support plate slides to abut against the guide plate, the spring is in a non-deformed state or an elastically compressed state.

[0018] In one possible implementation, the support plate has a slot on its outer side facing the horizontal direction, and the axis of the slot is perpendicular to the axis of the upper discharge port; the recycling box has an insertion hole that communicates with its interior and is adapted to communicate with the slot, and a limiting rod adapted to be inserted into the slot is slidably inserted into the insertion hole;

[0019] When the support plate slides to abut against the guide plate, the insertion hole and the slot are connected.

[0020] In one possible implementation, a feeding platform is slidably connected to the upper side of the recycling bin, and the feeding platform has a feeding hole that runs through the vertical direction and communicates with the feed inlet.

[0021] In one possible implementation, a guide component is fixedly provided on the upper side of the feeding platform; the guide component has a guide cavity that runs through the vertical direction and communicates with the feeding hole, and the cross-sectional area of ​​the guide cavity gradually decreases from top to bottom.

[0022] In one possible implementation, the upper side of the recycling bin is fixedly provided with two slide rails arranged side by side in the horizontal direction, and the feeding platform is slidably disposed on the upper side of the slide rails so that there is a gap between the lower side of the feeding platform and the upper side of the recycling bin.

[0023] In one possible implementation, the outer side of the recycling bin has a through hole, and the axis of the through hole is parallel to the axis of the upper discharge port; the screen has a sliding rod that is slidably inserted into the through hole and extends outwards, and the linear drive component is disposed on the outside of the recycling bin and is drivenly connected to the extended end of the sliding rod.

[0024] In one possible implementation, the linear drive component includes:

[0025] A rotating motor is fixedly mounted on the outer side of the recycling bin, with its power output axis parallel to the vertical direction, and a turntable coaxially connected to the power output end of the rotating motor; and

[0026] A connecting rod is disposed between the rotating motor and the slide rod; one end of the connecting rod is hinged to the extended end of the slide rod in the vertical direction, and the other end is hinged to the turntable in the vertical direction, and the connection between the connecting rod and the turntable is located outside the center of the turntable.

[0027] In one possible implementation, a discharge platform is slidably inserted into the lower discharge port, and the discharge platform has a hollow interior and an upward-facing opening.

[0028] When the feeding platform is inserted into the recycling bin, the material falling from the screen can fall into the feeding platform.

[0029] In this embodiment, the feed inlet allows stone chips to be fed into the recycling bin and fall onto the screen. During this process, the screen is moved back and forth by a linear drive component, which causes relative movement between the stone chips and the screen, thereby ensuring that fine-sized stone chips fall through the screen holes and coarse-sized stone chips remain on the upper side of the screen.

[0030] After the device has been running for a period of time, one or two support plates can be removed so that coarse-sized stone chips can be discharged to the outside through one or two guide plates and the upper discharge port, in order to avoid excessive accumulation of stone chips on the screen.

[0031] The stone slag recycling device for vertical shaft excavation provided in this embodiment, compared with the prior art, can ensure the rapid classification and discharge of stone slag, so as to avoid the problem of excessive stone slag on the screen and the clogging of the screen holes, thereby ensuring the efficiency of stone slag recycling. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is one of the three-dimensional structural schematic diagrams of the stone slag recycling device provided in the embodiments of this application;

[0034] Figure 2 for Figure 1 A magnified view of a portion of the middle circle A;

[0035] Figure 3 This is the second three-dimensional structural schematic diagram of the stone slag recycling device provided in the embodiments of this application;

[0036] Figure 4 This is a three-dimensional structural diagram of the screen and linear drive component used in the embodiments of this application from an exploded perspective;

[0037] Figure 5 This is a three-dimensional structural diagram of the recycling bin and unloading platform used in the embodiments of this application from an exploded perspective;

[0038] Figure 6 This is a cross-sectional structural schematic diagram of the stone slag recycling device provided in the embodiments of this application;

[0039] Figure 7 A partially enlarged cross-sectional view of the stone slag recycling device provided in the embodiments of this application;

[0040] Figure 8 This is a cross-sectional view of the loading platform and guide components used in the embodiments of this application in a combined state;

[0041] Figure 9 This is a three-dimensional structural diagram of the support plate used in the embodiments of this application;

[0042] Figure 10 This is a partially enlarged structural diagram of the recycling bin and rotating motor in their combined state as used in the embodiments of this application;

[0043] Explanation of reference numerals in the attached drawings: 1. Recycling bin; 11. Feed inlet; 12. Upper discharge outlet; 121. Protrusion; 13. Lower discharge outlet; 14. Insertion hole; 15. Limiting rod; 16. Slide rail; 17. Through hole; 2. Guide plate; 3. Support plate; 31. Bending part; 32. Slot; 4. Screen; 41. Slide rod; 5. Elastic reset component; 51. Guide rod; 52. Spring; 6. Linear drive component; 61. Rotary motor; 611. Turntable; 62. Connecting rod; 7. Loading platform; 71. Loading hole; 8. Guide component; 81. Guide cavity; 9. Unloading platform. Detailed Implementation

[0044] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0045] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0046] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0048] Please refer to the following: Figures 1 to 10 The present application describes the stone slag recovery device for vertical shaft excavation. The stone slag recovery device for vertical shaft excavation proposed in this application includes a recovery box 1, two guide plates 2, two support plates 3, and a screen 4.

[0049] The recycling bin 1 has a hollow internal structure and needs to be fixed on a horizontal surface during actual use to ensure the stability of the main body. The upper side of the recycling bin 1 has a feed inlet 11 communicating with its interior, which is used to feed a mixture of coarse and fine-grained stone chips. The outer side of the recycling bin 1 has two coaxially arranged upper discharge ports 12, located on two horizontally facing sides of the recycling bin 1, for removing coarse-grained stone chips. The outer side of the recycling bin 1 also has a lower discharge port 13 located below the upper discharge ports 12, for removing fine-grained stone chips.

[0050] Both guide plates 2 are installed inside the recycling bin 1 and correspond to the two upper discharge ports 12. Specifically, the guide plates 2 extend upward from the lower edge of the corresponding upper discharge ports 12 and are inclined toward the inside of the recycling bin 1. Furthermore, the side of the guide plates 2 facing the inside of the upper discharge ports 12 is connected to the recycling bin 1, so that the material falling on the guide plates 2 can fall into the upper discharge ports 12 along the inclined surface, avoiding the formation of gaps, so as to prevent the material from falling out through the gap between the side of the guide plates 2 and the inner wall of the recycling bin 1.

[0051] Two support plates 3 are slidably inserted into the two upper discharge ports 12, respectively. The surface of each support plate 3 is parallel to the horizontal plane, and the side of each support plate 3 facing the inner side of the upper discharge port 12 is connected to the recycling box 1. After the support plate 3 is inserted into the upper discharge port 12, its inserted end can abut against the extension end of the guide plate 2 on the same side, so that the guide plate 2 and the support plate 3 cooperate to achieve the technical purpose of closing the upper discharge port 12. Based on this, each support plate 3 has an elastic reset member 5 between it and the recycling box 1. This elastic reset member 5 can drive the support plate 3 to insert into the upper discharge port 12 to the position of abutting the guide plate 2, and the driving force provided by this elastic reset member 5 can be overcome manually.

[0052] The screen 4 is slidably disposed within the recycling bin 1 along the axial direction of the upper discharge port 12. Specifically, the screen 4 is located above the support plate 3, and the screen 4 is connected to a linear drive component 6 for reciprocating movement in a predetermined direction. During the movement of the screen 4, its two ends facing the direction of movement will successively create gaps with the inner side of the recycling bin 1, allowing the stone fragments to pass through. In this context, if the support plate 3 is pulled outward by overcoming the elastic force provided by the elastic reset component 5, the stone fragments can slide onto the guide plate 2 under their own gravity and finally be discharged from the upper discharge port 12.

[0053] In this embodiment, the feed inlet 11 allows stone chips to be fed into the recycling bin 1 and fall onto the screen 4. During this process, the screen 4 is driven to move back and forth by the linear drive component 6, which allows relative movement between the stone chips and the screen 4, thereby ensuring that fine-diameter stone chips fall through the screen holes and coarse-diameter stone chips remain on the upper side of the screen 4.

[0054] After the device has been running for a period of time, one or two support plates 3 can be removed so that coarse-sized stone chips can be discharged from one or two guide plates 2 through the upper discharge port 12 to the outside, in order to avoid excessive accumulation of stone chips on the screen 4.

[0055] The stone slag recycling device for vertical shaft excavation provided in this embodiment, compared with the prior art, can ensure the rapid classification and discharge of stone slag, so as to avoid the problem of excessive stone slag on the screen 4 and the clogging of the screen holes, thereby ensuring the efficiency of stone slag recycling.

[0056] In some embodiments, such as Figure 3 and Figure 6 As shown, the inner wall of the upper discharge port 12 has a protrusion 121, and the support plate 3 is slidably disposed between the protrusion 121 and the inner top surface of the upper discharge port 12, and the protrusion 121 provides support for the support plate 3.

[0057] Based on this, the support plate 3 has a bent portion 31 adapted to abut against the protrusion 121. Specifically, when the support plate 3 slides to abut against the guide plate 2, the bent portion 31 abuts against the protrusion 121 to limit further movement of the support plate 3.

[0058] By adopting the above technical solution, this setting is intended to prevent external operators from being unable to observe the insertion state of the support plate 3, thus preventing the support plate 3 and the extension end of the guide plate 2 from being unable to maintain contact; on the other hand, it ensures the stability of the overall structure, achieving a reliable effect where each end face has a corresponding end face in contact with it.

[0059] In some embodiments, such as Figure 2 and Figure 7 As shown, the elastic reset member 5 includes a guide rod 51 and a spring 52.

[0060] The guide rod 51 is fixedly connected to the protrusion 121 and extends outward from the recycling box 1 along the axial direction of the upper discharge port 12. The guide rod 51 is slidably connected to the aforementioned bent part 31.

[0061] Spring 52 is sleeved on the outer periphery of guide rod 51, with one end connected to the extension end of guide rod 51 and the other end of spring 52 connected to bent portion 31.

[0062] Based on the aforementioned structural features, when the support plate 3 slides to abut against the guide plate 2, the spring 52 is in a non-deformed state or an elastically compressed state to continuously provide a pushing force to the support plate 3 and prevent the support plate 3 and the guide plate 2 from separating.

[0063] In some embodiments, such as Figure 7 and Figure 9As shown, the support plate 3 has a slot 32 on its outer side facing the horizontal direction, and the axis of the slot 32 is perpendicular to the axis of the upper discharge port 12. Based on this, the recycling box 1 has an insertion hole 14 that communicates with its interior and is suitable for communicating with the slot 32, and a limiting rod 15 suitable for inserting into the slot 32 is slidably inserted into the insertion hole 14.

[0064] By adopting the above technical solution, when the support plate 3 slides to abut against the guide plate 2, the insertion hole 14 and the slot 32 are connected. At this time, the position of the support plate 3 can be locked by inserting the limiting rod 15 into the slot 32, so as to prevent the support plate 3 and the guide plate 2 from separating and improve the stability of the overall structure.

[0065] In some embodiments, such as Figure 1 , Figure 6 and Figure 8 As shown, a feeding platform 7 is slidably connected to the upper side of the recycling bin 1 in the horizontal direction; in this embodiment, the feeding platform 7 has a feeding hole 71 that runs through the vertical direction and communicates with the feeding port 11.

[0066] In actual use, the operator of the feeding operation feeds the material by placing it into the feeding hole 71 and periodically moving the feeding platform 7 to ensure the uniformity of the material when it is placed into the recycling box 1, and to avoid the adverse effects caused by too much material on one side.

[0067] Because the feed inlet 11 has a long, narrow structure, its width is relatively small, resulting in a small diameter for the feeding hole 71 and making feeding difficult. To solve this technical problem, in some embodiments, such as... Figure 1 , Figure 6 and Figure 8 As shown, a guide member 8 is fixedly provided on the upper side of the loading platform 7; in this embodiment, the guide member 8 has a guide cavity 81 that runs through the vertical direction and communicates with the loading hole 71, and the cross-sectional area of ​​the guide cavity 81 gradually decreases from top to bottom.

[0068] By adopting the above technical solution, the guide component 8 plays the role of collecting stone chips, solving the feeding problem caused by the small feeding hole 71.

[0069] In some embodiments, such as Figure 1 , Figure 6 and Figure 8 As shown, the upper side of the recycling bin 1 is fixedly provided with two slide rails 16 arranged in parallel along the horizontal direction; the feeding platform 7 is slidably arranged on the upper side of the slide rails 16, and its two sides are slidably connected to the two slide rails 16 respectively.

[0070] By adopting the above technical solution, the slide rail 16 can support the loading platform 7, so that a gap is formed between the lower side of the loading platform 7 and the upper side of the recycling box 1, thus avoiding structural damage caused by hard friction.

[0071] In some embodiments, such as Figure 3 , Figure 6 and Figure 10 As shown, a through hole 17 is provided on the outer side of the recycling box 1, and the axial direction of the through hole 17 is parallel to the axial direction of the upper discharge port 12; the screen 4 has a slide rod 41 that is slidably inserted into the through hole 17 and extends outward; the linear drive component 6 is provided on the outside of the recycling box 1 and is connected to the extended end of the slide rod 41 in a transmission manner, so as to achieve the technical purpose of externally storing the linear drive component 6.

[0072] In some embodiments, such as Figure 4 As shown, the linear drive component 6 includes a rotary motor 61 and a connecting rod 62.

[0073] The rotating motor 61 is fixedly installed on the outer side of the recycling bin 1. Its power output axis is parallel to the vertical direction, and a turntable 611 is coaxially connected to the power output end of the rotating motor 61.

[0074] The connecting rod 62 is disposed between the rotating motor 61 and the slide rod 41; one end of the connecting rod 62 is hinged to the extended end of the slide rod 41 in the vertical direction, and the other end is hinged to the turntable 611 in the vertical direction. The connection between the connecting rod 62 and the turntable 611 is located outside the center of the turntable 611, that is, it is eccentrically set relative to the center of the turntable 611.

[0075] By adopting the above technical solution, during the process of rotating the turntable 611 driven by the rotating motor 61, the connecting rod 62 will move and swing under its traction force, thereby driving the slide bar 41 to move back and forth, achieving the technical purpose of driving the screen 4.

[0076] In some embodiments, such as Figure 3 , Figure 5 and Figure 6 As shown, a feeding platform 9 is slidably inserted into the lower discharge port 13, and the feeding platform 9 has a hollow interior and an upward-facing opening.

[0077] By adopting the above technical solution, when the feeding platform 9 is inserted into the recycling box 1, the material falling from the screen 4 can fall into the feeding platform 9, so as to facilitate the recycling of fine-grained stone chips.

[0078] The above content is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A stone slag recycling device for vertical shaft excavation, characterized in that, include: The recycling bin has a hollow internal structure; the upper side of the recycling bin has a feed inlet, and the outer side has two coaxially arranged upper discharge outlets, as well as a lower discharge outlet located below the upper discharge outlets; Two guide plates are installed inside the recycling bin and correspond to the two upper discharge ports; the guide plates extend upward from the lower edge of the corresponding upper discharge ports and are inclined toward the inside of the recycling bin. Two support plates are slidably inserted into the two upper discharge ports, and each support plate has an elastic reset element between itself and the recycling box, so as to drive the support plate to insert and abut against the guide plate, thereby cooperating to close the upper discharge port; as well as A screen is slidably disposed inside the recycling bin along the axial direction of the upper discharge port, located on the upper side of the support plate, and the screen is connected to a linear drive component.

2. The stone slag recovery device for vertical shaft excavation as described in claim 1, characterized in that, The inner wall of the upper discharge port has a protrusion, the support plate is slidably disposed between the protrusion and the inner top surface of the upper discharge port, and the support plate has a bent portion adapted to abut against the protrusion. When the support plate slides to abut against the guide plate, the bent portion abuts against the protrusion.

3. The stone slag recovery device for vertical shaft excavation as described in claim 2, characterized in that, The elastic reset element includes: A guide rod, fixedly connected to the protrusion, extends axially away from the recycling bin along the upper discharge port and is slidably connected to the bent portion; and A spring is sleeved on the outer periphery of the guide rod, with one end connected to the extension end of the guide rod and the other end of the spring connected to the bent portion; When the support plate slides to abut against the guide plate, the spring is in a non-deformed state or an elastically compressed state.

4. The stone slag recovery device for vertical shaft excavation construction as described in any one of claims 1-3, characterized in that, The support plate has a slot on its outer side facing the horizontal direction, and the axis of the slot is perpendicular to the axis of the upper discharge port; the recycling box has an insertion hole that communicates with its interior and is suitable for communicating with the slot, and a limiting rod suitable for insertion into the slot is slidably inserted into the insertion hole; When the support plate slides to abut against the guide plate, the insertion hole and the slot are connected.

5. The stone slag recovery device for vertical shaft excavation as described in claim 1, characterized in that, The upper side of the recycling bin is slidably connected to a feeding platform, which has a feeding hole that runs vertically through the feed inlet.

6. The stone slag recovery device for vertical shaft excavation as described in claim 5, characterized in that, A guide component is fixedly provided on the upper side of the feeding platform; the guide component has a guide cavity that runs through the vertical direction and communicates with the feeding hole, and the cross-sectional area of ​​the guide cavity gradually decreases from top to bottom.

7. The stone slag recovery device for vertical shaft excavation as described in claim 5, characterized in that, The upper side of the recycling bin is fixedly provided with two slide rails arranged side by side in the horizontal direction, and the feeding platform is slidably disposed on the upper side of the slide rails so that there is a gap between the lower side of the feeding platform and the upper side of the recycling bin.

8. The stone slag recovery device for vertical shaft excavation as described in claim 1, characterized in that, The outer side of the recycling bin has a through hole, and the axis of the through hole is parallel to the axis of the upper discharge port; the screen has a sliding rod that is slidably inserted into the through hole and extends out; the linear drive component is located on the outside of the recycling bin and is connected to the extended end of the sliding rod.

9. The stone slag recovery device for vertical shaft excavation as described in claim 8, characterized in that, The linear drive component includes: A rotating motor is fixedly mounted on the outer side of the recycling bin, with its power output axis parallel to the vertical direction, and a turntable coaxially connected to the power output end of the rotating motor; and A connecting rod is disposed between the rotating motor and the slide rod; one end of the connecting rod is hinged to the extended end of the slide rod in the vertical direction, and the other end is hinged to the turntable in the vertical direction, and the connection between the connecting rod and the turntable is located outside the center of the turntable.

10. The stone slag recovery device for vertical shaft excavation as described in claim 1, characterized in that, A feeding platform is slidably inserted into the lower discharge port, and the feeding platform has a hollow interior and an upward-facing opening. When the feeding platform is inserted into the recycling bin, the material falling from the screen can fall into the feeding platform.

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