Telescopic coal dropping pipe

Abstract

The telescopic coal drop pipe comprises a box body, an adjusting mechanism and a guiding mechanism, the box body comprises a first box body and a second box body which are sequentially arranged in the vertical direction, the first end of the first box body is provided with a feeding port, the second end of the first box body is provided with a first connector, and the first end of the second box body is provided with a second connector; the first connector and the second connector are connected in a sleeved mode to be used for connecting the first box body and the second box body, and the adjusting mechanism comprises a first fixing piece, a first moving piece, a linear driving piece and a connecting piece. The distance between the first box body and the second box body is changed when the linear driving piece drives the first moving piece to move towards or move away from the first fixed piece, the guiding structure comprises a guiding rod, a second fixed piece and a second moving piece, and the second fixed piece is connected with the first box body. The telescopic coal drop pipe provided by the invention has the advantages that the length of the body is convenient to adjust, and the installation is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of mine coal conveying equipment, and in particular to a telescopic coal dropping pipe. Background Art

[0002] When transporting raw coal from the coal mining face to the coal storage yard, and in the process of unloading coal from the coal storage yard, the large height difference causes coal dust to fly, which not only pollutes the environment but also causes the loss of pulverized coal. The coal drop pipe is a general term for coal transportation pipelines in ports, thermal power, coal and other industries. It is a key device in the process of coal transportation and unloading, and plays a vital role in reducing coal dust and preventing the loss of pulverized coal.

[0003] The current coal drop pipe does not have a telescopic structure and cannot adjust the height of the discharge port. This structure has significant defects. When the coal drop pipe unloads coal, the coal pile on the coal loading device below continues to rise, but this type of coal drop pipe cannot maintain a fixed distance from the coal pile by adjusting the discharge port, resulting in a situation where the drop is too large in the initial stage of unloading and too small in the final stage, increasing the probability of coal block breakage and the amount of pulverized coal in the air, thereby increasing coal consumption and environmental pollution, resulting in this type of coal drop pipe being unable to quickly adjust between coal loading devices at different heights. Summary of the invention

[0004] To this end, an embodiment of the present invention provides a retractable coal dropping pipe, which has the advantages of being easy to adjust the length of the main body and convenient to install.

[0005] According to the telescopic coal dropping pipe of the embodiment of the present invention, the telescopic coal dropping pipe includes a box body, an adjustment mechanism and a guiding mechanism, the box body includes a first box body and a second box body arranged in sequence along the vertical direction, the first end of the first box body has a feed port, the second end of the first box body has a first interface, the first end of the second box body has a second interface, the second end of the second box body has a discharge port, the first interface and the second interface are socketed to connect the first box body and the second box body, the adjustment mechanism includes a first fixing member, a first moving member, a linear driving member, and a connecting member, the first end of the linear driving member is connected to the first fixing member, and the second end of the linear driving member is connected to the first fixing member. The first movable member is connected, the connecting member connects the first fixed member to the first box or the second box, the connecting member connects the first movable member to the second box or the first box, as the linear drive member drives the first movable member to move toward or away from the first fixed member, the distance between the first box and the second box is changed, the guiding structure includes a guiding rod, a second fixed member and a second movable member, the second fixed member is connected to the first box, the second movable member is connected to the second box, the first end of the guiding rod is connected to the second fixed member, and the second movable member is slidably connected to the second end of the guiding rod.

[0006] The retractable coal drop pipe according to the embodiment of the present invention has the advantages of easy adjustment of the body length and convenient installation. The coal drop pipe of the present application is height-adjustable, has strong adaptability to different coal receiving devices, and has a good effect of reducing coal dust.

[0007] In some embodiments, the linear drive member includes a driving part and a lead screw, the output end of the driving part is transmission-connected to the lead screw, the lead screw is pivotally connected to the first fixed member, and the lead screw is threadedly connected to the first movable member.

[0008] In some embodiments, the linear drive member further includes a first buffer member and a second buffer member, the first buffer member is sleeved on the lead screw, and the buffer member is connected to the first fixed member and the first movable member;

[0009] The second buffer member is sleeved on the guide member, and two ends of the second buffer member are respectively connected to the second fixing member and the second moving member.

[0010] In some embodiments, an extension mechanism is also included, which includes an extension screw, an extension screw head and an extension handle. The first end of the extension screw penetrates into the screw and is pivotally connected to the screw. The extension handle is connected to the extension screw through the extension screw head.

[0011] In some embodiments, an extended guide rod is threadedly connected to the bottom of the guide rod.

[0012] In some embodiments, the retractable coal drop pipe also includes a limit mechanism, which includes a first limit switch and an alarm, wherein the first limit switch is located on any one of the first box body, the second box body, the first fixed part, the first movable part, the second fixed part, and the second movable part, and the alarm is electrically connected to the limit switch to issue an alarm.

[0013] In some embodiments, the limiting mechanism further includes a limiting block, and the limiting block is located at one end of the lead screw and the guide rod adjacent to the second box body to prevent separation.

[0014] In some embodiments, the limit mechanism further includes a second limit switch, and the second limit switch is located on the second box body to abut against the limit block.

[0015] In some embodiments, the lead screw includes a shaft head, a shaft body, a shaft neck, a shaft shoulder and a threaded section, the first fixing member includes a fixing seat, a first bearing, a second bearing, a first locking nut and a bearing end cover, the fixing seat is connected to the outer wall of the first box body, a bearing hole is arranged in the center of the fixing seat, the first bearing and the second bearing are located in the bearing hole and are sleeved on the outside of the shaft neck, the first locking nut and the shaft shoulder clamp the first bearing and the second bearing in the vertical direction, the shaft body is threadedly connected to the first locking nut, bearing end covers are respectively arranged on the top of the first bearing and the bottom of the second bearing, the bearing end covers are abutted against the first bearing or the second bearing through an annular boss, and the shaft head is connected to the driving part. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 2 is a schematic diagram of the structure of a retractable coal drop pipe according to an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of the structure of the first fixed part and the first movable part of the telescopic coal dropping pipe according to an embodiment of the present invention.

[0018] Figure 3 It is a schematic diagram of the partial structure of the lead screw of the telescopic coal dropping pipe according to an embodiment of the present invention.

[0019] Figure numerals: 1, first housing; 2, second housing; 3, first fixed member; 4, first movable member; 5, connecting member; 6, guide rod; 7, second fixed member; 8, second movable member; 9, driving part; 10, lead screw; 101, shaft head; 102, shaft body; 103, shaft neck; 104, shaft shoulder; 105, bearing hole; 11, first buffer member; 12, second buffer member; 13, first bearing; 14, second bearing; 15, first locking nut; 16, bearing end cover. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0021] According to the telescopic coal dropping pipe of the embodiment of the present invention, the telescopic coal dropping pipe includes a box body, an adjusting mechanism and a guiding mechanism. The box body includes a first box body 1 and a second box body 2 arranged in sequence along the vertical direction. The first end of the first box body 1 has a feeding port, the second end of the first box body 1 has a first interface, the first end of the second box body 2 has a second interface, and the second end of the second box body 2 has a discharging port. The first interface and the second interface are socketed to connect the first box body 1 and the second box body 2. The adjusting mechanism includes a first fixing member 3, a first moving member 4, a linear driving member, and a connecting member 5. The first end of the linear driving member is connected to the first fixing member 3, and the linear driving member is connected to the first moving member 4. The second end of the member is connected to the first moving member 4, the connecting member 5 connects the first fixed member 3 to the first box body 1 or the second box body 2, and the connecting member 5 connects the first moving member 4 to the second box body 2 or the first box body 1. As the linear drive member drives the first moving member 4 to move toward or away from the first fixed member 3, the distance between the first box body 1 and the second box body 2 is changed. The guiding structure includes a guiding rod 6, a second fixed member 7 and a second moving member 8. The second fixed member 7 is connected to the first box body 1, and the second moving member 8 is connected to the second box body 2. The first end of the guiding rod 6 is connected to the second fixed member 7, and the second moving member 8 is slidably connected to the second end of the guiding rod 6. The first box body 1 has a rectangular feed port, and the first box body 1 has a hollow pipe inside. The feed port is connected to the belt conveyor of the coal transportation system. The other end of the first box body 1 is provided with a first interface, and the first interface is connected to the second box body 2. The opening position of the feed port is determined according to the position of the belt conveyor of the coal transportation system relative to the coal drop pipe, and can be set on the top surface or side of the first box body 1. The coal falls directly into the coal drop pipe at the end of the conveyor belt without falling from a higher position. This design greatly reduces the dust produced by the impact of coal during the falling process. Optionally, a dust-proof curtain is installed at the feed port to effectively prevent the dust generated by the collision of coal blocks in the coal drop pipe from drifting outward, and at the same time will not hinder the coal blocks from entering the coal drop pipe. The sliding fit between the first box body 1 and the second box body 2 has a guiding effect, which improves the structural rigidity of the coal drop pipe and reduces the shaking amplitude of the second box body 2 during the adjustment of the coal drop pipe. The discharge port is used to change the trajectory and speed direction of the coal block falling, which can reduce the vertical speed of the coal block when it falls into the coal conveying device below.

[0022] The telescopic coal drop pipe according to the embodiment of the present invention has the advantages of being easy to adjust the length of the main body and convenient to install.

[0023] In some embodiments, the linear drive member includes a driving part 9 and a lead screw 10 , the output end of the driving part 9 is transmission-connected to the lead screw 10 , the lead screw 10 is pivotally connected to the first fixed member 3 , and the lead screw 10 is threadedly connected to the first movable member 4 .

[0024] Specifically, the driving part 9 drives the lead screw 10 to rotate. The lead screw 10 is rotatably connected to the first fixing member 3 and can rotate relative to the first fixing member 3. The lead screw 10 is threadedly connected to the first moving member 4 so that the first moving member 4 can move up and down along the lead screw 10.

[0025] In some embodiments, the linear drive member further includes a first buffer member 11 and a second buffer member 12, the first buffer member 11 is sleeved on the lead screw 10, and the buffer member is connected to the first fixed member 3 and the first movable member 4;

[0026] The second buffer member 12 is sleeved on the guide member, and two ends of the second buffer member 12 are connected to the second fixing member 7 and the second moving member 8 respectively.

[0027] Specifically, the first buffer 11 and the second buffer 12 are both elastic members, which can be springs. The springs are sleeved on the lead screw 10 and the guide member to play a buffering role, reduce impact, and protect the fixed member. The pre-stretching of the spring can provide a certain upward restoring force to offset the gravity of the box below. It reduces the vibration and impact force of the lead screw 10 during operation, thereby extending the service life and improving the stability of the device operation.

[0028] In some embodiments, an extension mechanism is also included, which includes an extension screw 10, an extension screw 10 head and an extension handle. The first end of the extension screw 10 penetrates into the screw 10 and is pivotally connected to the screw 10. The extension handle is connected to the extension screw 10 through the extension screw 10 head.

[0029] Specifically, the extension mechanism extends the length of the screw 10 by adding an extension screw 10, which facilitates the installation of the second box body 2 and reduces the lifting strength. The coal drop pipe is usually installed at a high position that is difficult to reach. The assembled coal drop pipe has a large volume and mass and is inconvenient to lift. The distributed installation with the help of the extension mechanism can reduce the difficulty of lifting and improve efficiency. First, the first box body 1 is installed, and the second box body 2 is located below the first wheel. After the extension mechanism is installed, the extension mechanism is installed in conjunction with the second box body 2. The extension handle is turned to drive the second box body 2 to rise and close toward the first box body 1. After the second box body 2 exceeds the extension screw 10 and is threadedly connected with the screw 10, the extension mechanism is removed to avoid interference and collision between the extension device and the equipment below.

[0030] The steps for installing the cabinet are as follows:

[0031] Step A: The driving part 9, the lead screw 10, the first fixing member 3 and the second fixing member 7 of the guide mechanism are installed on the first box body 1, and the first box body 1 is fixed at the target installation position.

[0032] Step B: Install the first moving member 4 and the linear drive member on the second housing 2, and transfer the second housing 2 to the bottom of the installed first housing 1, and screw the threaded section of the extended lead screw 10 into the nut of the first moving member 4 of the lead screw 10. It should be noted that the screwing depth of the threaded section of the extended lead screw 10 is determined by the vertical distance between the lower end of the lead screw 10 and the nut, and this distance needs to make the length of the extended lead screw 10 exposed above the nut suitable for its rod head and rod neck to be inserted into the center hole of the lead screw 10 for installation. Fine-tune the position of the second housing 2 during installation, and do not bend the extended lead screw 10. After the insertion is completed, match the guide rod 6 on the other side with the linear bearing.

[0033] Step C: When the nut of the lead screw 10 is matched with the threaded section of the extended lead screw 10, the handle of the extended lead screw 10 is turned, and the second housing 2 is gradually raised along the axial direction of the extended lead screw 10 until the top of the internal thread of the nut of the lead screw 10 moves to the joint between the threaded section of the extended lead screw 10 and the lead screw 10. At this time, the external thread of the lead screw 10 is not aligned with the internal thread of the nut of the lead screw 10, so the nut will be stuck by the lead screw 10 and cannot continue to rise.

[0034] Step D: At this time, slowly rotate the screw 10 driving part 9 while rotating the extended screw 10 handle back and forth in a small range. After several attempts, the external thread of the screw 10 can be aligned with the internal thread of the screw 10 nut. At this time, the nut is matched with the external threads of the extended screw 10 and the screw 10 at the same time. Therefore, the driving part 9 and the extended screw 10 handle are rotated synchronously to make the screw 10 nut and the second box body 2 continue to rise until the screw 10 nut rises to the end of the extended screw 10, and then is completely transferred to the screw 10.

[0035] Step E: After completing step A to step D, the second housing 2 is installed in place, and the auxiliary function of the extension screw 10 in the installation process of the second housing 2 is completed. Because the extension screw 10 is located below the coal drop pipe, it may interfere with the coal conveying device, so it is necessary to remove the extension device, including the extension screw 10 handle and the extension screw 10. For the same purpose, the extension guide rod 6 is disassembled, and the threaded joint of the extension guide rod 6 is screwed out of the guide rod 6.

[0036] In some embodiments, an extended guide rod 6 is threadedly connected to the bottom of the guide rod 6 .

[0037] Specifically, the extended guide rod 6 is used to extend the length of the guide rod 6, so that the guide mechanism can cooperate with the installation of the second box body 2 to avoid the second box body 2 from tilting during the rising process, thereby improving the accuracy and efficiency of assembly.

[0038] In some embodiments, the retractable coal drop pipe also includes a limit mechanism, which includes a first limit switch and an alarm. The first limit switch is located on any one of the first box body 1, the second box body 2, the first fixed part 3, the first movable part 4, the second fixed part 7, and the second movable part 8. The alarm is electrically connected to the limit switch to issue an alarm.

[0039] Specifically, the limit mechanism is used to prevent the first box body 1 and the second box body 2 from moving beyond the limit. When the second box body 2 moves upward, it will cause a collision between the first box body 1 and the second box body 2. A first limit switch and an alarm are set at the edge of the socket of the first box body 1 and the second box body 2. When the second box body 2 slides upward to the limit switch, the alarm is triggered to remind the operator to stop the ascending operation. If the driving part 9 is a motor, the control system can also send a signal to stop the motor from rotating, thereby avoiding the collision of the two boxes. Protective equipment. It can be understood that the installation position of the first limit switch can also be the end of the screw rod, such as the screw rod fixing seat or other positions. As long as the distance between the first box body 1 and the second box body 2 is close to the collision distance, the position on the first box body 1 or the second box body 2 that can be approached by another object can achieve the installation position of the trigger limit switch. In actual installation, a suitable installation position can be selected according to the actual working conditions.

[0040] In some embodiments, the limiting mechanism further includes a limiting block, which is located at one end of the lead screw 10 and the guide rod 6 adjacent to the second box body 2 to prevent separation.

[0041] Specifically, the limit block is used to prevent the second box body 2 from moving too far away from the first box body 1, and to prevent the second box body 2 from slipping and falling on the lead screw 10. The limit block is arranged on the lead screw 10 and the guide rod 6 to protect the equipment.

[0042] In some embodiments, the limit mechanism further includes a second limit switch, and the second limit switch is located on the second box body 2 to abut against the limit block.

[0043] Specifically, the second limit switch is arranged on the second box body 2 and contacts the limit block. When the first moving member 4 on the lead screw 10 descends to contact the limit block, the second limit switch is triggered, and the second limit switch can trigger an alarm to remind the operator to stop the descending operation. If the driving part 9 is a motor, a signal can also be sent through the control system to stop the motor from rotating, thereby preventing the second box body 2 from slipping off the lead screw 10 and the guide rod 6 and falling.

[0044] In some embodiments, the screw 10 includes a shaft head 101, a shaft body 102, a shaft neck 103, a shaft shoulder 104 and a threaded section, the first fixing member 3 includes a fixing seat, a first bearing 13, a second bearing 14, a first locking nut 15 and a bearing end cover, the fixing seat is connected to the outer wall of the first box body 1, a bearing hole 105 is arranged in the center of the fixing seat, the first bearing 13 and the second bearing 14 are located in the bearing hole 105 and are sleeved on the outside of the shaft neck 103, the first locking nut 15 and the shaft shoulder 104 clamp the first bearing 13 and the second bearing 14 in the vertical direction, the shaft body 102 is threadedly connected to the first locking nut 15, and bearing end covers are respectively arranged on the top of the first bearing 13 and the bottom of the second bearing 14, the bearing end covers are abutted against the first bearing 13 or the second bearing 14 through an annular boss, and the shaft head 101 is connected to the driving part 9.

[0045] Specifically, the lead screw 10 is installed at the center of the first fixing member 3. The lead screw 10 is provided with a shaft head 101, a shaft body 102, a shaft neck 103, a shaft shoulder 104 and a threaded section from the upper end to the lower end. The first fixing member 3 includes a fixing seat, a first bearing 13, a second bearing 14, a first locking nut 15 and a bearing end cover. The fixing seat is fixed to the outer wall of the first housing 1, and a bearing hole 105 is provided at the center of the fixing seat. The first bearing 13 and the second bearing 14 are installed in the bearing hole 105. The shaft neck 103 of the lead screw 10 is matched with the inner rings of the first bearing 13 and the second bearing 14. At the same time, the shaft body 102 is provided with a thread and is matched with the thread of the first locking nut 15. By tightening the first locking nut 15, the first locking nut 15 and the shaft shoulder 104 simultaneously clamp the inner rings of the first bearing 13 and the second bearing 14, thereby completing the pre-tightening of the first bearing 13 and the second bearing 14. The bosses of the bearing end cover respectively support the outer rings of the first bearing 13 and the second bearing 14. The bearing end cover is fixed to the upper end face of the screw 10 fixing seat and the lower end face of the screw 10 fixing seat. The bearing end cover is provided with an annular boss, which extends into the bearing hole 105 and respectively presses against the outer rings of the first bearing 13 and the second bearing 14, thereby completing the axial positioning of the first bearing 13 and the second bearing 14, and axially fixing the screw 10 to the fixing seat. The shaft head 101 is located at the upper end of the screw 10 and has a keyway, which cooperates with the drive part 9 through a key. In this embodiment, the drive part 9 can be a handwheel or a motor. When the operator turns the drive part 9, the screw 10 rotates accordingly. The threaded section is located below the shaft shoulder 104.

[0046] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0047] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0048] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0050] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0051] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A retractable coal dropping pipe, characterized in that: include: A box body, the box body comprises a first box body and a second box body arranged in sequence along a vertical direction, the first end of the first box body has a feed port, the second end of the first box body has a first interface, the first end of the second box body has a second interface, the second end of the second box body has a discharge port, the first interface and the second interface are socketed to connect the first box body and the second box body; An adjustment mechanism, wherein the adjustment mechanism comprises a first fixed member, a first movable member, a linear drive member, and a connecting member, wherein a first end of the linear drive member is connected to the first fixed member, a second end of the linear drive member is connected to the first movable member, the connecting member connects the first fixed member to the first box or the second box, and the connecting member connects the first movable member to the second box or the first box, and as the linear drive member drives the first movable member to move toward or away from the first fixed member, the distance between the first box and the second box is changed; The guiding mechanism comprises a guiding rod, a second fixing member and a second moving member, wherein the second fixing member is connected to the first box body, the second moving member is connected to the second box body, the first end of the guiding rod is connected to the second fixing member, and the second moving member is slidably connected to the second end of the guiding rod.

2. The retractable coal drop pipe according to claim 1, characterized in that: The linear drive member includes a driving part and a lead screw, the output end of the driving part is transmission-connected to the lead screw, the lead screw is pivotally connected to the first fixed member, and the lead screw is threadedly connected to the first movable member.

3. The retractable coal drop pipe according to claim 2, characterized in that: It also includes a first buffer and a second buffer, wherein the first buffer is sleeved on the lead screw, and the buffer is connected to the first fixed member and the first movable member; The second buffer member is sleeved on the guide member, and two ends of the second buffer member are respectively connected to the second fixing member and the second moving member.

4. The retractable coal drop pipe according to claim 2, characterized in that: It also includes an extension mechanism, which includes an extension screw, an extension screw head and an extension handle. The first end of the extension screw penetrates into the screw and is pivotally connected to the screw. The extension handle is connected to the extension screw through the extension screw head.

5. The telescopic coal drop pipe according to claim 4, characterized in that: The bottom of the guide rod is threadedly connected with an extended guide rod.

6. The retractable coal drop pipe according to claim 2, characterized in that: It also includes a limit mechanism, which includes a first limit switch and an alarm. The first limit switch is located on any one of the first box body, the second box body, the first fixed member, the first movable member, the second fixed member, and the second movable member. The alarm is electrically connected to the limit switch to issue an alarm.

7. The telescopic coal drop pipe according to claim 6, characterized in that: It also includes a limit block, which is located at one end of the lead screw and the guide rod adjacent to the second box body to prevent them from disengaging.

8. The telescopic coal drop pipe according to claim 7, characterized in that: It also includes a second limit switch, which is located on the second box body and is used to abut against the limit block.

9. The retractable coal drop pipe according to claim 2, characterized in that: The lead screw includes a shaft head, a shaft body, a shaft neck, a shaft shoulder and a threaded section. The first fixing part includes a fixing seat, a first bearing, a second bearing, a first locking nut and a bearing end cover. The fixing seat is connected to the outer wall of the first box body. A bearing hole is arranged at the center of the fixing seat. The first bearing and the second bearing are located in the bearing hole and are sleeved on the outside of the shaft neck. The first locking nut and the shaft shoulder clamp the first bearing and the second bearing in the vertical direction. The shaft body is threadedly connected to the first locking nut. Bearing end covers are respectively arranged on the top of the first bearing and the bottom of the second bearing. The bearing end cover abuts against the first bearing or the second bearing through an annular boss. The shaft head is connected to the driving part.

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