Patent Publication Number: US-11384638-B2

Title: Apparatus for controllably unfolding flexible mesh for continuous miner, and continuous miner

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a 371 of international application of PCT application serial no. PCT/CN2018/112383, filed on Oct. 29, 2018, which claims the priority benefit of China application no. 201811058265.1, filed on Sep. 11, 2018. The entirety of each of the above mentioned patent applications is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Technical Field 
     The present invention relates to a continuous miner, more particularly to an apparatus for controllably unfolding a flexible mesh for a continuous miner and a continuous miner, and is suitable for driving a tunnel having a simple geologic condition, a small coal seam inclination angle, and a good roof self-stability. 
     Description of Related Art 
     In underground coal mining in China, with the constant improvement of mechanization, automation and intelligence levels, the fully-mechanized mining efficiency is gradually improved. In contrast, under the influence of the current matching technology, the tunneling speed is improved slowly, thereby causing the problem of imbalance between coal production and mining. Bolt support has the advantages of safety, flexibility, high efficiency and the like, and is a support method widely used in a coal mine tunnel in China. Mesh is a common surface protection member in bolt support, and the effects thereof are to maintain a rock mass between bolts to be complete, confine crushed rock fragments in situ, and maintain a three-dimensional stress state of a deep surrounding rock. In recent years, a flexible mesh made from a macromolecule material and used for underground coal mine bolt support is provided. The flexible mesh has the advantages of high strength, large bearing capacity, large single piece area and the like. However, the mesh is difficult to realize mechanical construction all the time, but is mostly completed by manpower. The high labor strength and low working efficiency are the factors seriously restricting tunneling mechanization, automation and intelligence. In addition, a worker generally needs to get close to an exposed rock mass during mesh construction. Therefore, the safety is poor. 
     SUMMARY 
     In order to solve the problems of high labor strength, low working efficiency, and poor safety in bolt support construction because mesh construction must be completed by manpower in bolt support, the present invention provides an apparatus for controllably unfolding a flexible mesh for a continuous miner and a continuous miner, improves the mesh unfolding mechanization level, and is suitable for the coal mines having a good roof and a large face-to-gob distance in west of China. 
     To achieve the above technical object, one technical solution adopted by the present invention is as follows. 
     An apparatus for controllably unfolding a flexible mesh for a continuous miner, including a mesh roll storage rack, a height adjustment post, a mesh rolling shaft and a flexible mesh. The flexible mesh consists of a mesh roll and an unfolded mesh. The mesh roll and the unfolded mesh are an integrated structure. The mesh roll is located on the mesh roll storage rack. The unfolded mesh is clamped on the mesh rolling shaft, and is pressed on a cut and un-supported tunnel roof via a roof bolt. The mesh rolling shaft is rotatably connected to a top portion of the height adjustment post. The mesh roll storage rack and the height adjustment post are both mounted on the continuous miner. The mesh rolling shaft is located at a back end of the mesh roll storage rack. 
     A plurality of mesh hanging disks are fixed on an outer surface of the mesh rolling shaft. The unfolded mesh is clamped on the mesh hanging disks. A limit mechanism and a damping mechanism are disposed on the mesh rolling shaft. The limit mechanism includes a limit oil cylinder, a limit slide bar and a limit gear. A limit cylinder body of the limit oil cylinder is fixedly connected to the height adjustment post. A limit piston rod of the limit oil cylinder is hinged to a bottom portion of the limit slide bar. The limit gear is fixed on the mesh rolling shaft, and is located above the limit slide bar. The limit oil cylinder is used to drive the limit slide bar to engage with a tooth space of the limit gear fixed to the mesh rolling shaft, so as to limit the mesh rolling shaft. The damping mechanism includes a damping slide bar, a damping spring, a damping slide bar base, a damping disk cover and an adjustment screw plug. The damping slide bar base is internally provided with a penetrative cavity extending in a length direction thereof. The adjustment screw plug is threadedly connected to a tail of the cavity in the damping slide bar base. A bottom end of the damping slide bar extends into the cavity from a top portion of the damping slide bar base. The damping spring is located in the cavity. A top portion of the damping spring is in contact with the bottom end of the damping slide bar, and a bottom portion of the damping spring is in contact with a top portion of the adjustment screw plug. The damping disk cover is fixed on the mesh rolling shaft. An outer surface of the damping disk cover is provided with a plurality of arc-shaped notches distributed in a circumferential direction thereof, and the arc-shaped notches are located above the damping slide bar. The damping spring is used to press the damping slide bar into the arc-shaped notches of the damping disk cover, so as to damp the mesh rolling shaft. 
     As a further improved technical solution of the present invention, the mesh rolling shaft includes an intermediate portion, a first side portion and a second side portion. The uniformly distributed mesh hanging disks are fixed on outer surfaces of the intermediate portion, the first side portion and the second side portion. Two ends of the intermediate portion are both provided with a first connecting shaft and a second connecting shaft which are connected to each other. The intermediate portion, the first connecting shaft and the second connecting shaft are an integrated structure, and diameters thereof progressively decrease. The intermediate portion, the first connecting shaft and the second connecting shaft are sequentially connected. One end portion of the first side portion and one end portion of the second side portion are both provided with a shaft hole cooperatively connected to the second connecting shaft. The second connecting shaft at one end of the intermediate portion extends into the shaft hole of the first side portion, and the second connecting shaft is connected to the shaft hole of the first side portion via a first flat key. The second connecting shaft at the other end of the intermediate portion extends into the shaft hole of the second side portion, and the second connecting shaft is connected to the shaft hole of the second side portion via a first flat key. 
     As a further improved technical solution of the present invention, a number of the height adjustment post is two. The top portion of one of the height adjustment posts is rotatably connected to the second connecting shaft at one end of the intermediate portion via a rolling bearing which is located at one end of the second connecting shaft connected to the first connecting shaft. The top portion of the other one of the height adjustment posts is rotatably connected to the second connecting shaft at the other end of the intermediate portion via a rolling bearing which is located at one end of the second connecting shaft connected to the first connecting shaft. An outer ring of each of the rolling bearings is in interference connection with the top portion of a respective one of the height adjustment posts. An inner ring of the rolling bearing is in interference connection with the second connecting shaft. 
     As a further improved technical solution of the present invention, a number of the limit mechanism and a number of the damping mechanism are both two. The limit gear in one of the limit mechanisms is fixedly connected to one end surface of the intermediate portion via a screw, and the limit gear is sleeved on the first connecting shaft connected to the end surface. The limit gear in the other one of the limit mechanisms is fixedly connected to the other end surface of the intermediate portion via a screw, and the limit gear is sleeved on the first connecting shaft connected to the end surface. The damping disk cover in one damping mechanism is fixedly connected, via a screw, to an end surface of the first side portion provided with the shaft hole, and the damping disk cover is sleeved on the second connecting shaft connected to the shaft hole. The damping disk cover in the other one of the damping mechanisms is fixedly connected, via a screw, to an end surface of the second side portion provided with the shaft hole, and the damping disk cover is sleeved on the second connecting shaft connected to the shaft hole. 
     As a further improved technical solution of the present invention, an annular clamping groove is respectively disposed on outer surfaces of the second connecting shafts at the two ends of the intermediate portion. Two semi-circular clamping keys are clamped in the annular clamping groove, and the two semi-circular clamping keys are fitted together to form a circular clamping key. An end surface of the semi-circular clamping key on the outer surface of the second connecting shaft at one end of the intermediate portion is in close contact with one end surface of the first side portion. An end surface of the semi-circular clamping key on the outer surface of the second connecting shaft at the other end of the intermediate portion is in close contact with one end surface of the second side portion. The damping disk cover includes a damping portion and a disk cover portion. The damping portion and the disk cover portion are connected to each other, and are an integrated structure. An outer surface of the damping portion is provided with a plurality of arc-shaped notches distributed in a circumferential direction thereof. A plurality of fixing holes are disposed on an outer surface of the disk cover portion. A circular groove for placing the semi-circular clamping keys is disposed on an inner wall of the disk cover portion. The disk cover portion in one damping disk cover is fixedly connected to one end surface of the first side portion via the fixing holes, and the groove on the inner wall of the disk cover portion and one annular clamping groove are in a same vertical direction. The disk cover portion in the other damping disk cover is fixedly connected to one end surface of the second side portion via the fixing holes, and the groove on the inner wall of the disk cover portion and the other annular clamping groove are in a same vertical direction. The semi-circular clamping key is located between the annular clamping groove and the groove on the inner wall of the disk cover portion. 
     As a further improved technical solution of the present invention, each of the limit mechanisms further includes a guide base. The guide base is located above the limit oil cylinder. The guide base is fixedly connected to a respective one of the height adjustment posts. The guide base is internally provided with a penetrative strip-shaped chamber extending in a length direction thereof. The limit slide bar penetrates through the strip-shaped chamber in the guide base. A first key groove is disposed on an inner wall of the strip-shaped chamber. A second key groove matched with the first key groove is disposed on an outer surface of the limit slide bar. A second flat key is fixed in the second key groove, and the second flat key is located in the first key groove, and the second flat key is slidably connected to the first key groove. 
     As a further improved technical solution of the present invention, an outer surface of the mesh hanging disk is provided with a plurality of inclined mesh hanging grooves distributed in a circumferential direction thereof. The unfolded mesh is clamped in the mesh hanging grooves. The mesh hanging disk is fixedly connected to the mesh rolling shaft by welding. The mesh roll storage rack includes a rack body and a plurality of support rollers arranged in an arc shape along the rack body. The support roller includes a support roller shaft and a support roller sleeve. Two ends of the support roller shaft are fixedly connected to the rack body. The support roller sleeve is sleeved outside the support roller shaft, and is rotatably connected to the support roller shaft. The mesh roll is located on the support roller. The rack body is mounted on the continuous miner. 
     As a further improved technical solution of the present invention, the height adjustment post includes a square inner sleeve, a square outer sleeve and a height adjustment oil cylinder. A bottom portion of the square outer sleeve is fixed on the continuous miner via a bolt. One end of the square inner sleeve is embedded in the square outer sleeve, and the square inner sleeve is slidably connected to the square outer sleeve. A bottom portion of a cylinder body of the height adjustment oil cylinder is hinged to the square outer sleeve via a lower pin shaft. A top portion of the cylinder body of the height adjustment oil cylinder extends into the square inner sleeve, and a piston rod of the height adjustment oil cylinder is hinged to the square inner sleeve via an upper pin shaft. A top portion of the square inner sleeve is rotatably connected to the mesh rolling shaft. The limit oil cylinder, the guide base and the damping slide bar base are all fixed on the square inner sleeve. The height adjustment oil cylinder is a double-acting cylinder. A lower oil port of the height adjustment oil cylinder extends out from a hole at the bottom portion of the square outer sleeve via a pipe, and is in communication with pressure oil. An upper oil port of the height adjustment oil cylinder sequentially extends out from the holes at a bottom portion of the square inner sleeve and at the bottom portion of the square outer sleeve via a pipe, and is in communication with pressure oil. 
     As a further improved technical solution of the present invention, the limit oil cylinder is a single-acting cylinder. An oil inlet of the limit oil cylinder is in communication with the pressure oil via a travel reversing valve on the continuous miner, so as to link the limit oil cylinder to an oilway of a travel mechanism on the continuous miner. 
     To achieve the above technical object, another technical solution adopted by the present invention is as follows. 
     A continuous miner includes the apparatus for controllably unfolding a flexible mesh for a continuous miner. 
     The beneficial effects of the present invention are as follows. The present invention controllably unfolds the flexible mesh by embedding mesh wires of the flexible mesh wound on the mesh rolling shaft in the mesh hanging groove of the mesh hanging disk, reduces manual operation, and has a high working efficiency and high safety. The limit mechanism can limit and release the mesh rolling shaft. When the mesh rolling shaft is limited, the mesh rolling shaft cannot rotate, ensuring that the flexible mesh cannot be unfolded. When the mesh rolling shaft is released, the mesh rolling shaft can rotate under an acting force of the flexible mesh, so as to release the flexible mesh. The action of the limit mechanism can be linked to an oilway of a hydraulic travel mechanism of the continuous miner, and can also be driven by a separately disposed hydraulic system. The present invention further provides a resistance adjustable damping mechanism for preventing the mesh rolling shaft from over-rotating to excessively unfold the mesh. The mesh roll storage rack is provided with a plurality of support rollers, facilitating the unfolding of the mesh roll under traction. The height adjustment post can adjust the height of the mesh rolling shaft under the drive of the hydraulic system, so as to adapt to different tunnel heights. The controllable unfolding apparatus according to the present invention can controllably unfold the flexible mesh under the traction of the continuous miner, can create conditions for performing a bolt support work in back of the continuous miner, and can implement cut and support works in parallel, thereby improving tunneling efficiency. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a continuous miner in an operating state during tunneling; 
         FIG. 2  is an oblique view of the continuous miner; 
         FIG. 3  is a structural schematic view of a mesh roll storage rack; 
         FIG. 4  is a structural schematic view of a flexible mesh wound on a mesh rolling shaft; 
         FIG. 5  is a sectional view of a part of the mesh rolling shaft; 
         FIG. 6  is a sectional view of a connection position between an intermediate portion of the mesh rolling shaft and a second side portion; 
         FIG. 7  is a sectional view of one end of the intermediate portion of the mesh rolling shaft; 
         FIG. 8  is an external view of one end of the intermediate portion of the mesh rolling shaft; 
         FIG. 9  is an external view of the connection position between the intermediate portion of the mesh rolling shaft and the second side portion; 
         FIG. 10  is a structural schematic view of a mesh hanging disk; 
         FIG. 11  is a structural schematic view of a damping disk cover; 
         FIG. 12  is a structural schematic view of an adjustment screw plug; 
         FIG. 13  is a structural schematic view of a height adjustment post; 
         FIG. 14  is a side view of  FIG. 13 ; and 
         FIG. 15  is a schematic view of a hydraulic linkage principle of a limit oil cylinder and a travel mechanism of the continuous miner. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Specific embodiments of the present invention will be further described hereafter according to  FIG. 1  to  FIG. 15 . 
     In order to solve the problems of high labor strength, low working efficiency, and poor safety in bolt support construction because mesh construction must be completed by manpower in bolt support, the present invention provides an apparatus for controllably unfolding a flexible mesh for a continuous miner and a continuous miner, which improves the mesh unfolding mechanization level. 
       FIG. 1  is a side view of a continuous miner in an operating state during tunneling. With reference to  FIG. 1 , the reference signs include tunnel floor  1 , tunnel working surface  2 , cut and unsupported tunnel roof  3 , roof bolt  5 , supported tunnel roof  6 , continuous miner  7 , and flexible mesh  4 . The embodiment provides a continuous miner including the apparatus for controllably unfolding a flexible mesh for a continuous miner  7 . The continuous miner  7  can controllably unfold the flexible mesh under the traction of the continuous miner  7 , can create conditions for performing a bolt support work in back of the continuous miner  7 , and can implement cut and support works in parallel, thereby improving tunneling efficiency. With reference to  FIG. 2 , the flexible mesh  4  on the continuous miner  7  includes a mesh roll  41  and an unfolded mesh  42 . The mesh roll  41  and the unfolded mesh  42  are integrally connected as one piece. The unfolded mesh  42  at the supported tunnel roof  6  is already pressed on the tunnel roof by the roof bolt  5  to play a support role. The unfolded mesh  42  in a region to be supported is tight, and is pending to be supported by the roof bolt  5 . Therefore, when the unfolded mesh  42  is not pressed by the roof bolt  5 , the unfolded mesh does not have the support effect. However, the roof bolt support cannot be constructed until the mesh is appropriately unfolded. 
     With reference to  FIG. 1 , the embodiment provides an apparatus for controllably unfolding a flexible mesh for a continuous miner, including a mesh roll storage rack A, a height adjustment post B, a mesh rolling shaft C and a flexible mesh  4 . With reference to  FIG. 2 , the flexible mesh  4  includes a mesh roll  41  and an unfolded mesh  42 . The mesh roll  41  and the unfolded mesh  42  are an integrated structure. The mesh roll  41  is located on the mesh roll storage rack A. With reference to  FIG. 4 , the unfolded mesh  42  is clamped on the mesh rolling shaft C, and is pressed on the cut and un-supported tunnel roof  3  via the roof bolt  5 , so as to form the supported tunnel roof  6 . The mesh rolling shaft C is rotatably connected to a top portion of the height adjustment post B. The mesh roll storage rack A and the height adjustment post B are both mounted on the continuous miner  7 . The mesh rolling shaft C is located at a back end of the mesh roll storage rack A. 
     With reference to  FIG. 3 , the mesh roll storage rack A includes a rack body A 2  and a plurality of support rollers A 1  arranged in an arc shape along the rack body A 2 . The support roller A 1  includes a support roller shaft A 12  and a support roller sleeve A 11 . Two ends of the support roller shaft A 12  are fixedly connected to the rack body A 2 . The support roller sleeve A 11  is sleeved outside the support roller shaft A 12 , and is rotatably connected to the support roller shaft A 12 . The mesh roll  41  is located on the support roller sleeve A 11  of the support roller A 1 . The rack body A 2  is mounted on the continuous miner  7 . The support roller sleeve A 11  of the support roller A 1  is used to bear the mesh roll  41  and ensure that the unfolding resistance of the mesh roll  41  decreases during unfolding. The support roller sleeve A 11  of the support roller A 1  can freely rotate. In addition, in the embodiment, a rotary shaft can be disposed in the middle of the mesh roll  41 . The two ends of the rotary shaft are connected to the rack body A 2  via a bracket. The rotary shaft can be rotatably connected to the bracket or not, which does not influence the other functions of the present invention. The mesh roll  41  is directly placed on the mesh roll storage rack A with no connection therebetween. The mesh roll  41  is in contact with the support roller A 1 . When the back unfolded mesh  42  drives the mesh roll  41  to unfold, the mesh roll  41  can freely rotate on the support roller A 1 , such that the mesh roll  41  can be passively unfolded. The net roll  41  and the unfolded net  42  are integrally connected as one piece. The unfolded mesh  42  at the supported tunnel roof  6  is already pressed on the roof by the bolt to play a support role. The unfolded mesh  42  in a region to be supported is tight, and is pending to be supported by the bolt. 
     With reference to  FIG. 4 , a plurality of mesh hanging disks C 4  are fixed on an outer surface of the mesh rolling shaft C. The unfolded mesh  42  is clamped on the mesh hanging disks C 4 . With reference to  FIG. 5 , two limit mechanism E and two damping mechanism D are disposed on the mesh rolling shaft C. With reference to  FIG. 6 , each of the limit mechanisms E includes a limit oil cylinder E 4 , a limit slide bar E 2  and a limit gear E 1 . A limit cylinder body E 44  of the limit oil cylinder E 4  is fixedly connected to the height adjustment post B. A limit piston rod E 41  of the limit oil cylinder E 4  is hinged to a bottom portion of the limit slide bar E 2 . The limit gear E 1  is fixed on the mesh rolling shaft C, and is located above the limit slide bar E 2 . The limit oil cylinder E 4  is used to drive the limit slide bar E 2  to engage with a tooth space of the limit gear E 1  fixed to the mesh rolling shaft C, so as to limit the mesh rolling shaft C. When the limit slide bar E 2  is drawn out, the limitation is released, and the mesh rolling shaft C can roll. Each of the damping mechanism D includes a damping slide bar D 1 , a damping spring D 2 , a damping slide bar base D 3 , a damping disk cover D 4  and an adjustment screw plug D 5 . The damping slide bar base D 3  is internally provided with a penetrative cavity extending in a length direction thereof. The cavity is divided into an upper cavity and a lower cavity. The cross sectional area of the upper cavity is less than the cross sectional area of the lower cavity. The adjustment screw plug D 5 , the damping spring D 2 , and a bottom end of the damping slide bar D 1  are all located in the lower cavity. The bottom end of the damping slide bar D 1  is in an inverted T shape which can prevent the bottom end of the damping slide bar D 1  from sliding into the upper cavity. The adjustment screw plug D 5  is threadedly connected to a tail of the cavity in the damping slide bar base D 3 . A bottom end of the damping slide bar D 1  extends into the cavity from a top portion of the damping slide bar base D 3 . The damping spring D 2  is located in the cavity. A top portion of the damping spring D 2  is in contact with the bottom end of the damping slide bar D 1 , and a bottom portion of the damping spring D 2  is in contact with a top portion of the adjustment screw plug D 5 . The damping disk cover D 4  is fixed on the mesh rolling shaft C. An outer surface of the damping disk cover D 4  is provided with a plurality of arc-shaped notches D 41  distributed in a circumferential direction thereof, and the arc-shaped notches D 41  are located above the damping slide bar D 1 . The adjustment screw plug D 5  is tightened. The damping spring D 2  is used to press the damping slide bar D 1  into the arc-shaped notches D 41  of the damping disk cover D 4 , so as to damp the mesh rolling shaft C. The structure of the adjustment screw plug D 5  is as shown in  FIG. 12 . 
     With reference to  FIG. 6 , the damping slide bar D 1  can slide in the damping slide bar base D 3  along the cavity. The damping spring D 2  is in contact with the bottom end of the damping slide bar D 1 . The adjustment screw plug D 5  is threadedly connected to the damping slide bar base D 3 . By rotating the adjustment screw plug D 5 , the adjustment screw plug D 5  is screwed in along the damping slide bar base D 3  via the screwed connection, squeezes and compresses the damping spring D 2 , and applies an outward thrust force to the damping slide bar D 1 , such that an end head of the damping slide bar D 1  enters the arc-shaped notch D 41  of the damping disk cover D 4  to clamp the damping disk cover D 4 . By adjusting the tightness of the adjustment screw plug D 5 , the damping slide bar D 1  can apply different damping forces to the damping disk cover D 4 . The damping disk cover D 4  is connected to the mesh rolling shaft C via a flange hole (namely the fixing hole D 44 ) and a bolt. 
     With reference to  FIG. 10 , an outer surface of the mesh hanging disk C 4  is provided with a plurality of inclined mesh hanging grooves C 42  distributed in a circumferential direction thereof. A disk gear C 41  is formed between every two adjacent mesh hanging grooves C 42 . The unfolded mesh  42  is clamped in the mesh hanging grooves C 42 . The mesh hanging disk C 4  is fixedly connected to the mesh rolling shaft C by means of welding. In the embodiment, the mesh wires of the flexible mesh  4  wound on the mesh rolling shaft C are embedded in the mesh hanging groove C 42  of the mesh hanging disk C 4 . The limit mechanism E can limit and release the mesh rolling shaft C. When limited, the mesh rolling shaft C cannot move, so as to ensure that the flexible mesh cannot be unfolded. When released, the mesh rolling shaft C can rotate under an acting force of the mesh, so as to release the mesh. The action of the limit mechanism E can be linked to an oilway of a hydraulic travel mechanism of the continuous miner, and can also be driven by a separately disposed hydraulic system. A resistance adjustable damping mechanism D is provided to prevent the mesh rolling shaft C from over-rotating to excessively unfold the mesh. The mesh roll storage rack A is provided with a plurality of support rollers A 1 , facilitating the unfolding of the mesh roll  41  under traction. The height adjustment post B can extend and retract under the drive of the hydraulic system to adjust the height of the mesh rolling shaft C, so as to adapt to different tunnel heights. The apparatus for controllably unfolding a flexible mesh for a continuous miner according to the present invention can controllably unfold the flexible mesh under the traction of the continuous miner, can create conditions for performing a bolt support work in back of the continuous miner, and can implement cut and support works in parallel, thereby improving tunneling efficiency. 
     With reference to  FIG. 5 , the mesh rolling shaft C includes an intermediate portion C 1 , a first side portion C 2  and a second side portion C 3 . The uniformly distributed mesh hanging disks C 4  are fixed on outer surfaces of the intermediate portion C 1 , the first side portion C 2  and the second side portion C 3 . With reference to  FIGS. 7 and 8 , the two ends of the intermediate portion C 1  are both provided with a first connecting shaft C 9  and a second connecting shaft C 10  which are connected to each other. The intermediate portion C 1 , the first connecting shaft C 9  and the second connecting shaft C 10  are an integrated structure, and the diameters thereof progressively decrease. The intermediate portion C 1 , the first connecting shaft C 9  and the second connecting shaft C 10  are sequentially connected. With reference to  FIG. 6 , one end portion of the first side portion C 2  and one end portion of the second side portion C 3  are both provided with a shaft hole cooperatively connected to the second connecting shaft C 10 . The second connecting shaft C 10  at one end of the intermediate portion C 1  extends into the shaft hole of the first side portion C 2 , and the second connecting shaft C 10  is connected to the shaft hole of the first side portion C 2  via a first flat key C 6 . By the same token, the second connecting shaft C 10  at the other one end of the intermediate portion C 1  extends into the shaft hole of the second side portion C 3 , and the second connecting shaft C 10  is connected to the shaft hole of the second side portion C 3  via a first flat key C 6 . The first flat key C 6  is located in a third key groove C 8  of the second connecting shaft C 10  as shown in  FIG. 8 . 
     With reference to  FIG. 5-7 , a number of the height adjustment post B is two. The top portion of one of the height adjustment posts B is rotatably connected to the second connecting shaft C 10  at one end of the intermediate portion C 1  via a rolling bearing C 11 , and the rolling bearing C 11  is located at one end of the second connecting shaft C 10  connected to the first connecting shaft C 9 . The top portion of the other one of the height adjustment posts B is rotatably connected to the second connecting shaft C 10  at the other end of the intermediate portion C 1  via a rolling bearing C 11 , and the rolling bearing C 11  is located at one end of the second connecting shaft C 10  connected to the first connecting shaft C 9 . With reference to  FIG. 7 , an inner ring of the rolling bearing C 11  is in interference connection with the second connecting shaft C 10 . An outer wall of the rolling bearing C 11  is fixedly connected to the top portion of a respective one of the height adjustment posts B. The top portion of each of the height adjustment posts B is an annular structure B 21 . The annular structure B 21  is sleeved on an outer ring of the rolling bearing C 11 , and closely presses against (or in interference connection with) the outer ring of the rolling bearing C 11 . One end surface of the inner ring of the rolling bearing C 11  is in close contact with an end surface of the first connecting shaft C 9 . The other end surface of the inner ring of the rolling bearing C 11  is in close contact with a circlip for shaft C 12 . The circlip for shaft C 12  is fixed on an outer surface of the second connecting shaft C 10 , and can prevent the rolling bearing C 11  from sliding out of the second connecting shaft C 10 . In addition, the annular structure B 21  is further connected to an annular cover plate B 22  via a screw. A boss at an end surface of the annular cover plate B 22  is in close contact with one end surface of the outer ring of the rolling bearing C 11 . An inner surface of the annular structure B 21  is in close contact with the other end surface of the outer ring of the rolling bearing C 11 , and can also prevent the rolling bearing C 11  from sliding out of the second connecting shaft C 10 . 
     The mesh rolling shaft C is connected to the height adjustment post B via the mesh rolling shaft C 11  with no motive force therebetween. The unfolded mesh  42  is fixed to the roof. When the continuous miner travels, the mesh roll  41  travels with the continuous miner under the action of traction, and is passively unfolded. 
     With reference to  FIG. 5 , a number of the limit mechanism E and a number of the damping mechanism D are both two. The limit gear E 1  in one limit mechanism E is fixedly connected to one end surface of the intermediate portion C 1  via a screw, and the limit gear E 1  is sleeved on the first connecting shaft C 9  connected to the end surface. The limit gear E 1  in the other limit mechanism E is fixedly connected to the other end surface of the intermediate portion C 1  via a screw, and the limit gear E 1  is sleeved on the first connecting shaft C 9  connected to the end surface. The damping disk cover D 4  in one damping mechanism D is fixedly connected, via a screw, to an end surface of the first side portion C 2  provided with the shaft hole, and the damping disk cover D 4  is sleeved on the second connecting shaft C 10  connected to the shaft hole. The damping disk cover D 4  in the other damping mechanism D is fixedly connected, via a screw, to an end surface of the second side portion C 3  provided with the shaft hole, and the damping disk cover D 4  is sleeved on the second connecting shaft C 10  connected to the shaft hole. 
     With reference to  FIG. 8 , an annular clamping groove C 7  is respectively disposed on the outer surfaces of the second connecting shafts C 10  at the two ends of the intermediate portion C 1 . Two semi-circular clamping keys C 5  (as shown in  FIG. 7 ) are clamped in the annular clamping groove C 7 , and the two semi-circular clamping keys C 5  are fitted together to form a circular clamping key. An end surface of the semi-circular clamping key C 5  on the outer surface of the second connecting shaft C 10  at one end of the intermediate portion C 1  is in close contact with one end surface of the first side portion C 2 . An end surface of the semi-circular clamping key C 5  on the outer surface of the second connecting shaft C 10  at the other end of the intermediate portion C 1  is in close contact with one end surface of the second side portion C 3 . With reference to  FIG. 11 , the damping disk cover D 4  includes a damping portion D 42  and a disk cover portion D 43 . The damping portion D 42  and the disk cover portion D 43  are connected to each other, and are an integrated structure. An outer surface of the damping portion D 42  is provided with a plurality of arc-shaped notches D 41  distributed in the circumferential direction thereof. A plurality of fixing holes D 44  are disposed on an outer surface of the disk cover portion D 43 . A circular groove D 45  (as shown in  FIG. 7 ) for placing the semi-circular clamping keys C 5  is disposed on an inner wall of the disk cover portion D 43 . The disk cover portion D 43  in one damping disk cover D 4  is fixedly connected to one end surface of the first side portion C 2  via the fixing holes D 44 , and the groove D 45  on the inner wall of the disk cover portion D 43  and one annular clamping groove C 7  are in the same vertical direction. The disk cover portion D 43  in the other damping disk cover D 4  is fixedly connected to one end surface of the second side portion C 3  via the fixing holes D 44 , and the groove D 45  on the inner wall of the disk cover portion D 43  and the other annular clamping groove C 7  are in the same vertical direction. The semi-circular clamping key C 5  is located between the annular clamping groove C 7  and the groove D 45  on the inner wall of the disk cover portion D 43 . 
     With reference to  FIG. 7 , totally two semi-circular clamping keys C 5  are disposed at each end of the intermediate portion C 1 , and are clamped in the annular clamping groove C 7  of the intermediate portion C 1  to form a complete annular structure. The effects thereof are to axially position the intermediate portion C 1  and the first side portion C 2 , and axially position the intermediate portion C 1  and the second side portion C 3 . Two first flat keys C 6  are also disposed at each end, and are mounted in the third key groove C 8  of the intermediate portion C 1 , so as to position the intermediate portion C 1  and the first side portion C 2  in a circumferential direction. The connection between the intermediate portion C 1  and the second side portion C 3  is the same as above. With the above method, the intermediate portion C 1  and the first side portion C 2  as well as the second side portion C 3  are axially and circumferentially positioned. 
     With reference to  FIGS. 6, 7 and 9 , the limit mechanism E further includes a guide base E 5 . The guide base E 5  is located above the limit oil cylinder E 4 . The guide base E 5  is fixedly connected to the height adjustment post B. The guide base E 5  is internally provided with a penetrative strip-shaped chamber extending in a length direction thereof. The limit slide bar E 2  penetrates through the strip-shaped chamber in the guide base E 5 . A first key groove is disposed on an inner wall of the strip-shaped chamber. A second key groove matched with the first key groove is disposed on an outer surface of the limit slide bar E 2 . A second flat key E 3  is fixed in the second key groove, and the second flat key E 3  is located in the first key groove. The second flat key E 3  is slidably connected to the first key groove. 
     With reference to  FIGS. 13 and 14 , each of the height adjustment posts B includes a square inner sleeve B 2 , a square outer sleeve B 1  and a height adjustment oil cylinder B 3 . A bottom portion of the square outer sleeve B 1  is fixed on the continuous miner  7  via a bolt. One end of the square inner sleeve B 2  is embedded in the square outer sleeve B 1 , and the square inner sleeve B 2  is slidably connected to the square outer sleeve B 1 . A bottom portion of a cylinder body of the height adjustment oil cylinder B 3  is hinged to the square outer sleeve B 1  via a lower pin shaft B 5 . A top portion of the cylinder body of the height adjustment oil cylinder B 3  extends into the square inner sleeve B 2 , and a piston rod of the height adjustment oil cylinder B 3  is hinged to the square inner sleeve B 2  via an upper pin shaft B 4 . A top portion of the square inner sleeve B 2  is rotatably connected to the mesh rolling shaft C. The limit oil cylinder E 4 , the guide base E 5  and the damping slide bar base D 3  are all fixed on the square inner sleeve B 2 . The height adjustment oil cylinder B 3  is a double-acting cylinder. A lower oil port of the height adjustment oil cylinder B 3  extends out from a hole B 6  at the bottom portion of the square outer sleeve B 1  via a pipe, and is in communication with pressure oil. An upper oil port of the height adjustment oil cylinder B 3  sequentially extends out from the holes B 6  at a bottom portion of the square inner sleeve B 2  and at the bottom portion of the square outer sleeve B 1  via a pipe, and is in communication with pressure oil. The height adjustment oil cylinder B 3  is driven by the separated disposed hydraulic system. 
     The limit oil cylinder E 4  is a single-acting cylinder. An oil inlet of the limit oil cylinder E 4  is in communication with the pressure oil via a travel reversing valve F 5  of a travel mechanism on the continuous miner  7 , so as to link the limit oil cylinder E 4  to an oilway of a travel mechanism on the continuous miner  7 . Specifically, with reference to  FIG. 15 ,  FIG. 15  illustrates a first shuttle valve F 1 , a second shuttle valve F 2 , a third shuttle valve F 3 , and a manual reversing valve F 4 . Two oil inlets of the first shuttle valve F 1  are both connected to the travel reversing valve F 5  on the continuous miner  7 . The travel reversing valve F 5  on the continuous miner  7  is connected to an oil return box and pressure oil. An oil outlet of the first shuttle valve F 1  is connected to an oil inlet of the second shuttle valve F 2 . An oil outlet of the second shuttle valve F 2  is connected to one oil inlet of the third shuttle valve F 3 . The other oil inlet of the third shuttle valve F 3  is connected to an operating oil port of the manual reversing valve F 4 . The manual reversing valve F 4  is a two-position three-way valve. An oil return port of the manual reversing valve F 4  is connected to the oil return box. An oil inlet of the manual reversing valve F 4  is connected to the pressure oil. An oil outlet of the third shuttle valve F 3  is connected to the oil inlet of the limit oil cylinder E 4 . The two oil inlets of the first shuttle valve F 1  are respectively connected to a hydraulic travel motor F 6  on the continuous miner  7  in parallel. The first shuttle valves F 1 , the travel reversing valves F 5 , and the hydraulic travel motors F 6  are all two. The travel mechanism of on the existing continuous miner  7  generally includes a hydraulic travel motor F 6  and a travel reversing valve F 5 . The limit oil cylinder E 4  is linked to the travel mechanism of the continuous miner. When the continuous miner displaces, the limit piston rod E 41  of the limit oil cylinder E 4  retracts, and drives the limit slide bar E 2  to draw out from the groove of the limit gear E 1  and release the limit to the mesh rolling shaft C. When the continuous miner does not travel, the limit oil cylinder E 4  extends out the limit piston rod E 41  under the drive of a reset spring E 43 , so as to push the limit slide bar E 2  into the tooth space of the limit gear E 1 , thereby limiting and locking the mesh rolling shaft C. 
     The operating principle of the limit oil cylinder E 4  is as follows. When the travel mechanism of the continuous miner travels, the actions of the travel reversing valve F 5  are to supply oil to the hydraulic travel motor F 6  and simultaneously output the pressure oil to the first shuttle valve F 1 . The pressure oil is then enters the limit oil inlet E 42  of the limit oil cylinder E 4  via the second shuttle valve F 2  and the third shuttle valve F 3 , so as to release the limit to the mesh rolling shaft C. if the limit to the mesh rolling shaft C needs to be released when the continuous miner does not travel, then hydraulic oil can be supplied to the limit oil inlet E 41  of the limit oil cylinder E 4  via the manual reversing valve F 4 , such that the purpose of releasing the limit to the mesh rolling shaft can also be achieved. When the manual reversing valve F 4  does not need to manually release locking, the manual reversing valve F 4  switch the pressure oil to the oil return box for loading off. When the manual reversing valve needs to manually release locking, a handle of the manual reversing valve F 4  is operated to reverse the valve and switch the pressure oil to the third shuttle valve F 3 . The pressure oil enters the limit oil cylinder E 4  via the third shuttle valve F 3 , and drives the limit oil cylinder E 4  to release locking. 
     The operating principle of the limit mechanism E is as follow. With reference to  FIG. 6  and  FIG. 7 , the limit oil cylinder E 4  in the limit mechanism E includes a limit cylinder body E 44 , a limit piston rod E 41 , a limit oil inlet E 42 , a breathing hole E 45 , and a reset spring E 43 . The limit oil cylinder E 4  is a single-acting cylinder. When the continuous miner does not travel, the limit oil inlet E 42  bears no pressure, the reset spring E 53  pushes a piston rod (namely the limit piston rod E 41 ) of the single-acting cylinder, the limit piston rod E 41  then pushes the limit slide bar E 2  to extend out, a tip of the limit slide bar E 2  is inserted in the tooth space of the limit gear E 1 , so as to get stuck the limit gear E 1  and then get stuck the entire mesh rolling shaft C 1 . The mesh hanging disk C 4  hooks the flexible mesh  4 , the mesh roll C 41  cannot continuously be unfolded, the back unfolded mesh C 42  is tightened, and a worker performs the roof support work under the tightened mesh. When the continuous miner travels, the hydraulic system supplies the pressure oil to the limit oil inlet E 42 , the pressure oil compresses the reset spring E 43 , drives the limit piston rod E 41  of the limit oil cylinder E 4  and then drives the limit slide bar E 2  to retract. The limit slide bar E 2  slides out from the tooth space of the limit gear E 1 , releases the limit to the limit gear E 1 , and then releases the limit to the mesh rolling shaft C. The unfolded mesh C 42  is already fixed on the tunnel roof by a bolt support system. Therefore, when the continuous miner travels forward, the mesh rolling shaft C passively rotates under the traction of the unfolded mesh C 42 . The mesh roll  41  is automatically unfolded to be the unfolded mesh C 42 . The process can be completed by the linked hydraulic system without manual intervention. The mesh roll  41  can be directly placed on the mesh roll storage rack A. Alternatively, a rotary shaft can be mounted on the mesh roll storage rack A, and the mesh roll  41  can be wound and fixed on the rotary shaft, as long as the gravity or a tensile force of the mesh roll  41  can tighten the unfolded mesh C 42 . The operating principle of the damping mechanism D is as follows. The adjustment screw plug D 5  presses the damping spring D 2 , and the damping spring D 2  pushes the damping slide bar D 1  to extend out. The head of the damping slide bar D 1  is embedded in the damping disk cover D 4 . When the mesh rolling shaft C needs to rotate, only a big enough traction force is provided, can the resistance of the damping slide bar D 1  be overcome and the damping slide bar D 1  be pressed back. With the method, the mesh rolling shaft C is prevented from automatically backward rotating which leads to excessive unfolding of the mesh roll  41  and loosing of the unfolded mesh  42 .