A counting device to improve the service life of chute bends

Abstract

This invention discloses a counting device for improving the service life of chute elbows, comprising: a chute body for transferring steel balls from the top to the next production system, including a horizontal chute, a vertical chute, and an elbow for connecting the inclined horizontal and vertical chutes; an impact energy-absorbing buffer plate located above the elbow of the chute body for absorbing and buffering the steel balls transferred on the chute body; and an acoustic-optical counting device installed on the chute body and connected to the impact energy-absorbing buffer plate for counting and statistically analyzing the steel balls passing through the impact energy-absorbing buffer plate. This invention can significantly reduce the impact kinetic energy of the steel balls, weaken or even eliminate the impact of the steel balls on the chute elbow, thereby achieving the expected goal of extending the service life of the chute body elbow, and can also accurately count and statistically analyze the steel balls passing through the detection area.

Description

Technical Field

[0001] This invention relates to the field of chute technology, and more specifically to a counting device that can improve the service life of chute bends. Background Technology

[0002] Chutes are widely used in the material transportation field of industrial production sites. They are mainly used to receive various solid particles and powdery materials transported by belts or pipelines and transfer them to the next production operation process.

[0003] In mining operations, all types of grinding mills require steel balls as grinding media to grind and crush materials. Due to limited space, most steel ball chutes are designed with bends to change the direction of the steel balls. Because steel balls are hard and heavy, and often roll down from a height, they will have a large impact on the chute at the bend due to inertia, causing severe wear in this area. If the wear is complete and the steel balls leak, the entire production system will be damaged, and falling steel balls can cause injury to nearby personnel and equipment, resulting in significant economic losses.

[0004] Currently, the industry mostly adopts a replaceable design for chute elbows, which can be replaced as a whole or reinforced by welding after grinding. However, this method has disadvantages such as high cost and passive handling. The production process also requires statistical analysis of the number of steel balls transported by the chute. Currently, it mainly relies on manual counting of sorted steel balls, which is inefficient, time-consuming, labor-intensive, and costly.

[0005] Therefore, this application proposes a counting device that can improve the service life of chute bends to solve the above-mentioned technical problems. Summary of the Invention

[0006] The main objective of this invention is to provide a counting device that can improve the service life of chute elbows by using a replaceable, freely rotatable wear-resistant plate to absorb and eliminate the impact kinetic energy of steel balls, thereby extending the service life of chute elbows, and by using laser and acoustic sensors to achieve statistical counting functions.

[0007] The present invention solves the above-mentioned technical problems by adopting the following technical solutions:

[0008] A counting device for improving the service life of chute bends includes:

[0009] The chute body, used for transferring steel balls from the top to the next production system, includes a horizontal chute, a vertical chute, and an elbow for connecting the inclined horizontal and vertical chutes.

[0010] Impact energy-absorbing buffer plate, located above the bend of the chute body, is used to absorb and buffer the energy of the steel balls being transferred on the chute body.

[0011] The sound and light counting device is installed on the main body of the chute and connected to the impact energy-absorbing buffer plate. It is used to count and statistically analyze the steel balls that pass through the impact energy-absorbing buffer plate.

[0012] Preferably, the transverse chute is inclined, and the sidewalls of the transverse chute, vertical chute, and bend are all provided with chute side plates for restricting the direction of steel ball transfer.

[0013] Preferably, the chute body further includes a protective shell disposed on the bend for mounting an impact energy-absorbing buffer plate.

[0014] Preferably, the impact energy-absorbing buffer plate includes a rotating bearing installed on the side plate of the chute or the protective shell, a receiving shaft set on the inner bushing of the rotating bearing, a wear-resistant plate set in the middle of the receiving shaft, and a soft rubber set on the surface of the wear-resistant plate for contacting the transfer steel ball for energy absorption and buffering treatment.

[0015] Preferably, the acoustic-optical counting device includes a device housing disposed on the bend head for connecting the receiving shaft, a laser emitting device disposed on the outside of the device housing, a laser receiving device disposed on the outside of the device housing, and a data processing module located inside the device housing and connected to the laser receiving device via an external data line for processing the counting statistics. The emission port of the laser emitting device is aligned with the laser receiving device for counting the steel balls passing through the chute body.

[0016] Preferably, the housing of the device is further provided with a sound-sensitive device for counting and statistical analysis when the steel ball contacts the impact energy-absorbing buffer plate and makes a sound. The sound-sensitive device is connected to the data processing module through an external data line.

[0017] Preferably, the device housing is further provided with an auxiliary counting structure for counting the number of rotations of the steel ball after the impact energy-absorbing buffer plate contacts it. The receiving shaft rotates on the device housing and one end of the receiving shaft extends into the device housing for connection with the auxiliary counting structure.

[0018] Preferably, the auxiliary counting structure includes a one-way bearing disposed inside the device housing and connected to the receiving shaft by the inner bushing, a pressure block mounted on the outer bushing of the one-way bearing, a spring disposed inside the device housing for connecting to the end of the pressure block, a contact button disposed inside the device housing for pressing the pressure block, and a counting module disposed inside the device housing for electrically connecting the contact button. The counting module is connected to the data processing module through an external data line.

[0019] During the process of the impact energy-absorbing buffer plate contacting the steel ball, the wear-resistant plate drives the receiving shaft to rotate. The receiving shaft drives the pressure block to rotate away from the contact button through a one-way bearing. During the process of the impact energy-absorbing buffer plate separating from the steel ball, the wear-resistant plate drives the receiving shaft to rotate and reset. The receiving shaft drives the pressure block to rotate and press the button end of the contact button through a one-way bearing and a spring. The counting module completes one count.

[0020] Preferably, it also includes a feeding control structure disposed on the chute body to limit the number of steel balls that pass through the laser emission area of ​​the laser emitting device on the transverse chute.

[0021] Preferably, the feeding control structure includes a mounting block installed on the protective housing, a mounting slot on the mounting block for engaging with the edge of the protective housing, two sets of connecting brackets on the mounting block, and a trapezoidal plate at the end of the connecting brackets for fitting against the upper surface of the transverse chute. The two sets of trapezoidal plates cooperate with each other to limit the number of steel balls passing through the laser emission area of ​​the laser emitting device.

[0022] This invention provides a counting device that can improve the service life of chute bends. Compared with the prior art, the advantages of this invention are reflected in:

[0023] 1. This invention involves installing an impact-absorbing buffer plate in the bend area facing the direction of the rolling steel ball. When the steel ball is encountered, the buffer plate first contacts the soft rubber, absorbing some of the kinetic energy. The entire impact-absorbing buffer plate rotates under the impact of the steel ball, converting, absorbing, and consuming the kinetic energy of the steel ball. Under the combined effect, the impact kinetic energy of the steel ball is greatly reduced, weakening or even eliminating the impact of the steel ball on the bend of the chute, thereby achieving the expected goal of extending the service life of the bend of the main body of the chute.

[0024] 2. This invention uses an acoustic-optical counting device, a laser emitting device and a laser receiving device to count and count the steel balls passing through the detection area, and an acoustic device to count and count when the steel balls make a sound when they contact the impact energy-absorbing buffer plate. The two devices complement each other and verify each other to improve the accuracy of the counting.

[0025] 3. By setting up interconnected impact energy-absorbing buffer plates and sound and light counting devices, this invention can not only greatly improve the service life of the main bend of the chute, but also automatically count and count the sorted steel balls, reducing the labor intensity and production cost of manual counting. It has the advantages of simple structure, convenient material, few consumable parts, and low maintenance cost. Moreover, compared with traditional chute, the method of further modification is simple and easy to implement, the modification difficulty is low, and it is convenient for rapid modification and maintenance management.

[0026] 4. By further setting an auxiliary counting structure, the present invention can utilize the rotation and reset of the impact energy-absorbing buffer plate when the steel ball contacts the impact energy-absorbing buffer plate to perform auxiliary counting, thereby improving the accuracy of counting.

[0027] 5. By further setting the feeding control structure, the present invention can control the number of steel balls entering the detection area by utilizing the channel distance formed between the two sets of trapezoidal plates, which facilitates precise technology and avoids the problem that the impact kinetic energy of the steel balls cannot be efficiently absorbed due to multiple steel balls contacting the impact energy-absorbing buffer plate. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0029] Figure 1 This is an overall perspective view of the present invention;

[0030] Figure 2 This is a stereoscopic view of the feed control structure of the present invention in its installed state. Figure 1 ;

[0031] Figure 3 This is a stereoscopic view of the feed control structure of the present invention in its installed state. Figure 2 ;

[0032] Figure 4 This is a three-dimensional view of the overall feed control structure of the present invention;

[0033] Figure 5 This is a three-dimensional schematic diagram of the installation structure of the acoustic-optical counting device of the present invention;

[0034] Figure 6 This is a three-dimensional schematic diagram of the impact energy-absorbing buffer plate installation structure of the present invention;

[0035] Figure 7 This is a three-dimensional cross-sectional schematic diagram of the acoustic-optical counting device of the present invention;

[0036] Figure 8 for Figure 7 Enlarged view of point A in the middle;

[0037] Figure 9 This is a schematic diagram of the system connection of the data processing module of the present invention.

[0038] In the picture:

[0039] 1. Main body of the chute; 11. Horizontal chute; 12. Vertical chute; 13. Bend head; 14. Side plate of the chute; 15. Protective shell;

[0040] 2. Impact-absorbing buffer plate; 21. Rotary bearing; 22. Support shaft; 23. Wear-resistant sheet material; 24. Soft rubber;

[0041] 3. Acoustic and optical counting device; 31. Device housing; 32. Laser emitting device; 33. Laser receiving device; 34. Acoustic sensor; 35. Data processing module; 36. Auxiliary counting structure; 361. One-way bearing; 362. Pressure block; 363. Contact button; 364. Spring; 365. Counting module;

[0042] 4. Feed control structure; 41. Mounting block; 42. Mounting slot; 43. Connecting bracket; 44. Trapezoidal plate. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] For details in the embodiments, please refer to Figures 1 to 9 .

[0045] like Figure 1 As shown, the present invention provides a counting device that can improve the service life of chute bends, comprising:

[0046] The chute body 1 is configured as an open container. The upper part is used to receive the steel balls after they fall into the chute, and the internal structure is used to make the steel balls move along the internal trajectory of the chute and transfer the steel balls to the next production system. The chute body 1 includes a horizontal chute 11, a vertical chute 12 and an elbow 13 for connecting the inclined horizontal chute 11 and the vertical chute 12.

[0047] Impact energy-absorbing buffer plate 2 is installed in the area above the bend head 13 of the chute body 1, facing the direction of the rolling of the steel ball. It is used to absorb and buffer the steel ball being transferred on the chute body 1. Therefore, it can greatly reduce the impact kinetic energy of the steel ball, weaken or even eliminate the impact of the steel ball on the bend head of the chute, thereby achieving the expected goal of extending the service life of the bend head 13 of the chute body 1.

[0048] The sound and light counting device 3 is installed on the chute body 1 and connected to the impact energy absorption buffer plate 2. It is used to count and statistically analyze the steel balls that pass through the impact energy absorption buffer plate 2 in the detection area.

[0049] Among them, such as Figure 1 and Figure 5 As shown, the transverse chute 11 is inclined so that the steel ball rolls down in a single direction after falling into the chute body 1. The side walls of the transverse chute 11, the vertical chute 12 and the bend 13 are all provided with chute side plates 14 to restrict the transfer direction of the steel ball. At this time, the chute side plates 14 can be used to place the two ends of the impact energy absorption buffer plate 2.

[0050] In addition, such as Figure 1 , Figure 2 and Figure 3 As shown, the chute body 1 also includes a protective shell 15 disposed on the bend head 13 to protect and restrict the movement of steel balls near the surface of the bend head 13. In this case, the protective shell 15 can prevent the steel balls from moving too fast and detaching from the chute body 1, and can also be used to place and install the impact energy-absorbing buffer plate 2 at both ends.

[0051] like Figure 5 , Figure 6 and Figure 7 As shown, in one specific embodiment, the impact energy-absorbing buffer plate 2 includes a rotating bearing 21 that is fixedly installed on the chute side plate 14 or the protective shell 15 and can roll freely, a receiving shaft 22 provided on the inner bushing of the rotating bearing 21, a wear-resistant plate 23 provided in the middle of the receiving shaft 22, and soft rubber 24 provided on the surface of the wear-resistant plate 23 for contacting the transfer steel ball. At this time, the wear-resistant plate 23 plays a supporting role, and the soft rubber 24 plays a role in contacting the transfer steel ball and absorbing energy and buffering.

[0052] Specifically, by installing the impact energy-absorbing buffer plate 2 in the bend head 13 area facing the direction of the rolling steel ball, when it encounters the steel ball, it first contacts the soft rubber 24 to absorb some of the kinetic energy. The entire impact energy-absorbing buffer plate 2 will rotate under the impact of the steel ball, converting, absorbing and consuming the kinetic energy of the steel ball. Under the combined effect, the impact kinetic energy of the steel ball is greatly reduced, and the impact of the steel ball on the bend head of the chute is weakened or even eliminated, thereby achieving the expected goal of extending the service life of the bend head 13 of the chute body 1.

[0053] It should be noted that the rotating bearing 21 mentioned above can be directly adopted from existing ball bearings, and the wear-resistant plate 23 and soft rubber 24 mentioned above are both existing technologies and can be directly adopted from existing wear-resistant plate and soft rubber 24 structures.

[0054] like Figure 7 and Figure 9As shown, in a specific embodiment, the acoustic-optical counting device 3 includes a device housing 31 disposed on the bend head 13 for connecting the receiving shaft 22, a laser emitting device 32 disposed on the outside of the device housing 31, a laser receiving device 33 disposed on the outside of the device housing 31, and a data processing module 35 located inside the device housing 31 and connected to the laser receiving device 33 via an external data line for processing counting statistics. The laser emitting device 32 emits its emission port aligned with the laser receiving device 33 and detects the laser passing through the internal space of the chute body 1. At this time, the laser emitting device 32 and the laser receiving device 33 can be used to count and statistically analyze the steel balls passing through the detection area of ​​the chute body 1.

[0055] In addition, the housing 31 is equipped with an acoustic sensor 34 for counting and statistical analysis when the steel ball makes a sound when it contacts the impact energy-absorbing buffer plate 2. The acoustic sensor 34 is connected to the data processing module 35 through an external data line. Therefore, the laser emitting device 32, the laser receiving device 33 and the acoustic sensor 34 can complement each other and verify each other to improve the accuracy of counting.

[0056] It should be noted that the laser emitting device 32, laser receiving device 33, data processing module 35, and acoustic sensing device 34 mentioned above are all existing technologies. They can be directly adopted from existing integrated laser transmitting and receiving devices (using laser reflection for detection) or existing separate laser detection equipment (such as...). Figure 5 The laser emitting device 32 emits laser light and the laser receiving device 33 receives laser light (counting is performed based on whether the laser receiving device 33 receives laser feedback). The data processing module 35 can directly adopt the data processing computer in the prior art (the physical computer performs data processing for counting and statistics using relevant algorithms). The sound-sensitive device 34 directly adopts the sound receiving device in the prior art (counting is performed based on changes in volume).

[0057] In summary, by setting up interconnected impact energy-absorbing buffer plates 2 and sound and light counting devices 3, the service life of the curved head 13 of the chute body 1 can be greatly improved, and the sorted steel balls can be automatically counted and counted, reducing the labor intensity and production cost of manual counting. It has the advantages of simple structure, convenient material sourcing, few consumable parts, and low maintenance cost.

[0058] Compared to traditional sluices, this device has a structure that allows for further modifications based on traditional sluices, and the modification methods are simple, easy to implement, and easy to maintain and manage.

[0059] In a specific embodiment, the device housing 31 is further provided with an auxiliary counting structure 36 for counting the number of rotations of the impact energy-absorbing buffer plate 2 after it contacts the steel ball. The auxiliary counting structure 36 can use the rotation and reset of the impact energy-absorbing buffer plate 2 when the steel ball contacts the impact energy-absorbing buffer plate 2 to assist in counting, so as to improve the accuracy of counting. The receiving shaft 22 rotates on the device housing 31 and one end of the receiving shaft 22 extends into the device housing 31 for connection with the auxiliary counting structure 36.

[0060] Specifically, such as Figure 8 As shown, the auxiliary counting structure 36 includes a one-way bearing 361 disposed inside the device housing 31 and connected to the receiving shaft 22 by the inner bushing, a pressure block 362 mounted on the outer bushing of the one-way bearing 361, a spring 364 disposed inside the device housing 31 for connecting to the end of the pressure block 362, a contact button 363 disposed inside the device housing 31 for pressing the pressure block 362, and a counting module 365 disposed inside the device housing 31 for electrically connecting the contact button 363. The counting module 365 is connected to the data processing module 35 through an external data line.

[0061] During use, when the impact energy-absorbing buffer plate 2 contacts the steel ball, the wear-resistant plate 23 drives the receiving shaft 22 to rotate. The receiving shaft 22 drives the pressure block 362 to rotate away from the contact button 363 through the one-way bearing 361. During the separation of the impact energy-absorbing buffer plate 2 from the steel ball, the wear-resistant plate 23 drives the receiving shaft 22 to rotate and reset. The receiving shaft 22 drives the pressure block 362 to rotate and press the button end of the contact button 363 through the one-way bearing 361 and the spring 364. The counting module 365 completes one count.

[0062] Therefore, the data processing module 35 can summarize the statistical techniques of the laser receiving device 33, the acoustic sensing device 34 and the counting module 365 to improve the accuracy of the counting statistics.

[0063] At this time, the receiving shaft 22 can reduce the impact kinetic energy of the steel ball through the wear-resistant plate 23 and soft rubber 24, weaken or even eliminate the impact of the steel ball on the chute bend, and can also use the auxiliary counting structure 36 to perform auxiliary counting and statistics on the number of steel balls by rotating the receiving shaft 22 when the wear-resistant plate 23 and soft rubber 24 come into contact with the steel ball, so as to improve the accuracy of counting the steel balls passing through the detection area.

[0064] In addition, such as Figure 2 , Figure 3 and Figure 4As shown, in one specific embodiment, the device may further include a feeding control structure 4 disposed on the chute body 1 to limit the number of steel balls passing through the laser emission area of ​​the laser emitting device 32 on the transverse chute 11. In this case, the feeding control structure 4 can control the number of steel balls entering the detection area, which facilitates accurate technical operation and avoids the problem that the impact kinetic energy of the steel balls cannot be efficiently absorbed due to multiple steel balls contacting the impact energy-absorbing buffer plate 2.

[0065] Specifically, the feeding control structure 4 includes a mounting block 41 installed on the protective housing 15, a mounting slot 42 on the mounting block 41 for engaging with the edge of the protective housing 15, two sets of connecting brackets 43 on the mounting block 41, and a trapezoidal plate 44 at the end of the connecting brackets 43 for abutting against the upper surface of the transverse chute 11. The two sets of trapezoidal plates 44 cooperate with each other to limit the number of steel balls passing through the detection area (the area traversed by the laser of the laser emitting device 32 and the laser receiving device 33).

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0067] Furthermore, it should be noted that if any directional indication (such as up, down, left, right, front, back, etc.) is involved in the embodiments of the present invention, the directional indication is only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0068] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, in the embodiments of this invention, "multiple" refers to two or more. Moreover, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

Claims

1. A counting device for improving the service life of chute bends, characterized in that, include: The chute body (1) is used to transfer steel balls from the top to the next production system, including a horizontal chute (11), a vertical chute (12) and an elbow (13) for connecting the inclined horizontal chute (11) and the vertical chute (12). Impact energy-absorbing buffer plate (2) is located above the bend (13) of the chute body (1) and is used to absorb and buffer the steel balls transferred on the chute body (1). The sound and light counting device (3) is set on the chute body (1) and connected to the impact energy absorption buffer plate (2) for counting and statistical operations on the steel balls passing through the impact energy absorption buffer plate (2); The transverse chute (11) is inclined, and the side walls of the transverse chute (11), the vertical chute (12) and the bend (13) are all provided with chute side plates (14) for restricting the direction of steel ball transfer. The chute body (1) also includes a protective shell (15) provided on the bend (13) for installing the impact energy-absorbing buffer plate (2). The impact energy-absorbing buffer plate (2) includes a rotating bearing (21) installed on the side plate (14) of the chute or the protective shell (15), a receiving shaft (22) set on the inner bushing of the rotating bearing (21), a wear-resistant plate (23) set in the middle of the receiving shaft (22), and a soft rubber (24) set on the surface of the wear-resistant plate (23) for contacting the transfer steel ball for energy absorption and buffering treatment. The sound and light counting device (3) includes a device housing (31) set on the bend (13) for connecting the receiving shaft (22), a laser emitting device (32) set on the outside of the device housing (31), a laser receiving device (33) set on the outside of the device housing (31), and a data processing module (35) located inside the device housing (31) and connected to the laser receiving device (33) via an external data line for processing the counting statistics. The laser emitting device (32) has its emission port aligned with the laser receiving device (33) for counting the steel balls passing through the chute body (1). The housing (31) of the device is also equipped with a sound-sensitive device (34) for counting and statistical analysis when the steel ball makes a sound when it contacts the impact energy-absorbing buffer plate (2). The sound-sensitive device (34) is connected to the data processing module (35) through an external data line. The device housing (31) is also provided with an auxiliary counting structure (36) for counting the number of rotations of the steel ball after the impact energy-absorbing buffer plate (2) contacts it. The receiving shaft (22) rotates on the device housing (31) and one end of the receiving shaft (22) extends into the device housing (31) for connection with the auxiliary counting structure (36). The auxiliary counting structure (36) includes a one-way bearing (361) disposed inside the device housing (31) and connected to the receiving shaft (22) by the inner bushing, a pressure block (362) mounted on the outer bushing of the one-way bearing (361), a spring (364) disposed inside the device housing (31) for connecting to the end of the pressure block (362), a contact button (363) disposed inside the device housing (31) for pressing the pressure block (362), and a counting module (365) disposed inside the device housing (31) for electrically connecting the contact button (363). The counting module (365) is connected to the data processing module (35) through an external data line. During the process of the impact energy-absorbing buffer plate (2) contacting the steel ball, the wear-resistant plate (23) drives the receiving shaft (22) to rotate, and the receiving shaft (22) drives the pressure block (362) to rotate away from the contact button (363) through the one-way bearing (361). During the separation process of the impact energy-absorbing buffer plate (2) from the steel ball, the wear-resistant plate (23) drives the receiving shaft (22) to rotate and reset. The receiving shaft (22) drives the pressure block (362) to rotate and press the button end of the contact button (363) through the one-way bearing (361) and the spring (364), so that the counting module (365) completes one count. It also includes a feed control structure (4) set on the chute body (1) to limit the number of steel balls passing through the laser emission area of ​​the laser emission device (32) on the transverse chute (11).

2. The counting device for improving the service life of chute bends as described in claim 1, characterized in that, The feeding control structure (4) includes a mounting block (41) installed on the protective housing (15), a mounting slot (42) provided on the mounting block (41) for engaging with the edge of the protective housing (15), two sets of connecting brackets (43) provided on the mounting block (41), and a trapezoidal plate (44) provided at the end of the connecting bracket (43) for attaching to the upper surface of the transverse chute (11). The two sets of trapezoidal plates (44) cooperate with each other to limit the number of steel balls passing through the laser emission area of ​​the laser emitting device (32).

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