Electromagnetic coil dispenser for improving waterproof performance

Information

  • Patent Application
  • 20200190980
  • Publication Number
    20200190980
  • Date Filed
    February 24, 2020
    4 years ago
  • Date Published
    June 18, 2020
    3 years ago
  • Inventors
    • Zhu; Xuejun
Abstract
The invention discloses a protective device for the occurrence of a mine roof fall, which includes a machine body. A load-bearing cavity 72 is provided in the machine body 10, a load-bearing platform 11 is fixedly arranged on the lower side of the machine body 10, and four circumferences of the machine body 10 are evenly distributed on the outside. The cavity 69 and the load-bearing cavity 72 are provided with a weight-bearing device 75 for lifting a weight. The weight-bearing device can withstand the falling top plate, and the hydraulic cylinder therein can make the device bear the pressure of the top plate on the device and fix the device at the same time. The stabilizing device can keep the device in a stable state under the action of pressure, will not fall, and share part of the pressure. The load-bearing device can support the device to support the pressure on the roof of the mine and drill into the ground. The fixing device can effectively Reduce the harm caused by the mine roof accident, reduce the accident casualties and various losses, and increase the safety rate in the mine production.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority from Chinese application No. 2019111217626 filed on Sep. 19, 2019 which is hereby incorporated by reference in its entirety.


TECHNICAL FIELD

The invention relates to the field of mine safety, in particular to a protection device used when a mine roof falls.


BACKGROUND OF THE INVENTION

At present, with the development of society, the roof fall is the phenomenon of natural collapse of the upper ore rock layer during underground mining. After the mining, the originally balanced mine pressure was destroyed. The root cause of the roof fall accident is the mining pressure during the mining process. As a result of the activity, the roof deformed to varying degrees during the pressure of the mine. First, cracks appeared along the joints of the roof and delamination occurred. If the roof is not properly protected, the support quality is not good, the pressure continues to increase, and the rock deformation exceeds elasticity Deformation limit, there will be fractures, falls, gangs or partial roofing. The harm caused by it is one is human casualties, the other is property damage, and the third is environmental damage.


BRIEF SUMMARY OF THE INVENTION

The object of the present invention is to provide a protection device for the occurrence of a roof fall of a mine, so as to solve the problems raised in the background art described above.


In order to achieve the above object, the present invention provides the following technical solution: a protection device for a mine roof fall, comprising a body, the body is provided with a load-bearing cavity, a load-bearing platform is fixedly arranged on the lower side of the body, and the body There are four circumferentially evenly spaced cavities on the outside, and a load-bearing device for lifting heavy objects is provided in the load-bearing cavity;


The weight supporting device includes a placing plate fixedly installed on the lower side wall of the load-bearing cavity. A protective shell is fixed on the side of the placing plate, and a protective shell is fixedly connected to the side of the placing plate. A main motor, the main motor is connected to a motor spline shaft, a first bevel gear is fixed on the motor spline shaft, and a second bevel gear shaft is rotatably connected to the left side wall of the protective housing, and the first A second bevel gear meshing with the first bevel gear is fixed on the right side of the second bevel gear shaft, and a first pulley fixedly connected to the second bevel gear shaft is provided on the left side of the second bevel gear. A large hydraulic cylinder is fixed on the side of the placing plate, and the large hydraulic cylinder is powered by a hydraulic rod. A hydraulic plate is fixed on the upper side of the hydraulic rod. A hydraulic column is fixed on the upper side of the hydraulic plate. A hydraulic spring is connected between the heavy platform and the hydraulic plate, and four supporting columns distributed in a circumferential array are fixed on the side of the placing plate, and a supporting spring is connected between the placing plate and the supporting platform;


A transmission cavity is provided in the load bearing platform, a drilling cavity is provided on the lower side of the transmission cavity, a weight bearing device is provided in the transmission cavity, and a load bearing platform is slidably connected to the upper side of the body, and the support A wheel cavity is provided in the weight table, a sliding cavity is provided on the upper side of the wheel cavity, and a stabilizing device for stabilizing the machine is provided on the outside of the body.


On the basis of the above technical solution, a cylindrical groove is provided on the lower side of the weighting platform, and the motor spline extends axially through the protective housing into the cylindrical groove of the weighting platform, and the motor spline A shaft is rotatably connected on the lower side of the pulley cavity, and a second pulley is fixed on the upper side of the motor spline shaft. A second shaft is rotatably connected on the lower side wall of the pulley cavity, and the second shaft is fixed on the upper side. A second auxiliary wheel is provided. A second belt is connected between the second auxiliary wheel and the second pulley. A top block is slidably connected in the sliding cavity. The top block is provided with a large spiral hole and A small spiral hole, the upper side of the second wheel shaft is fixedly provided with a large spiral rod that spirally rotates with the top block in the large spiral hole, and a spline screw is fixed on the upper side of the large spiral rod. The upper side of the key screw is slidably connected with a spiral column block that can be spirally rotated on the side wall of the small spiral hole, and a large drill bit is fixed on the upper side of the spiral column block.


On the basis of the above technical solution, the stabilization device includes four connecting rods fixedly installed in a circumferential array distributed on the lower side of the supporting platform, and each of the connecting rods is sleeved outside the supporting platform and the placement A compression spring connected between the plates, the connecting rods extend downward through the placing plate and enter the cavity, the connecting rods can slide up and down in the placing plates, and the lower side of each of the connecting rods is fixed A concave block is provided, and a rotating shaft is rotatably connected to the front and back sides of the cavity. A connecting block is hinged on the rotating shaft. A rotating shaft torsion spring is connected between the rotating shaft and the connecting block. A support is fixed on the connecting block. A long rod, a convex block is fixed on the lower side of the support rod, a friction block is fixed on the upper side of the support rod, an upper engaging block is fixed on the inner side of the support rod, and the outer side of the supporting platform is fixed. There are four lifting rods distributed in a circular array, and a lower engaging block is fixed on the outer side of each of the lifting rods, and the upper engaging block is matched with the lower engaging block.


On the basis of the above technical solution, the load bearing device includes a first wheel shaft rotatably mounted on the right wall of the transmission cavity, a first auxiliary wheel is fixed on the right side of the first wheel shaft, and a left side of the first wheel shaft is fixed on the left side. A third bevel gear is provided, a first belt is connected between the first auxiliary wheel and the first pulley, and an upper side of the transmission cavity is rotationally connected between the transmission cavity and the drilling cavity. A fourth bevel gear shaft rotationally connected to the wall, a second gear meshing with the third bevel gear is fixed on the fourth bevel gear shaft, and a first gear is fixed on the lower side of the fourth bevel gear shaft. A symmetrical gear shaft is rotatably connected to the upper side wall of the drilling cavity, and a helical spring is fixed on each of the gear shafts. A fixed spline is fixed on the lower side of the helical spring. There is a long spiral rod, a fourth bevel gear is connected between the long spiral rod and the upper side wall of the drilling cavity, and a small drill bit is fixed on the lower side of the long spiral rod.


In summary, the present invention has the beneficial effects that the device can withstand the falling roof when a roof fall accident occurs in the mine, prevent serious mine accidents, prevent serious personal injury, property damage, and environmental damage. It can withstand the falling top plate, and the hydraulic cylinder in it can make the device withstand the pressure of the top plate on the device.


At the same time, the device is fixed and the stabilizing device can keep the device in a stable state under the pressure, and it will not fall down and share the part Pressure and load-bearing device can make the device support the pressure on the roof of the mine and drill into the ground. Fix the device. This device can effectively reduce the harm caused by the roof accident, reduce the casualties and various losses, and increase the mine. Safety rate during production.





BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly explain the embodiments of the invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely For some embodiments of the invention, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without paying creative labor.



FIG. 1 is a schematic front view of a protective device for a full-scale cutaway of a protective device when a mine roof falls;



FIG. 2 is a cross-sectional view in the direction A-A in FIG. 1 of the present invention; FIG.



FIG. 3 is a partial enlarged view of B of FIG. 1 of the present invention;



FIG. 4 is a partially enlarged view of the position C in FIG. 1 of the present invention.





DETAILED DESCRIPTION OF THE INVENTION

All features disclosed in this specification, or all disclosed methods or steps, except for mutually exclusive features and/or steps, may be combined in any way.


Any feature disclosed in this specification (including any additional claims, abstract, and drawings), unless specifically stated otherwise, may be replaced by other equivalent or similar purpose alternative features. That is, unless specifically stated, each feature is just one example of a series of equivalent or similar features.


The present invention is described in detail below with reference to FIGS. 1-4. For convenience of description, the orientation described below is defined as follows: the up-down, left-right, front-back direction described below is consistent with the up-down, left-right, front-back direction of the projection relationship of FIG. 1 itself.


Please refer to FIGS. 1-4. An embodiment of the present invention provides a protection device for a mine roof fall, which includes a body 10, wherein the body 10 is provided with a load-bearing cavity 72, and the lower side of the body 10 is fixed. A load-bearing platform 11 is provided. Four circularly-spaced cavities 69 are evenly distributed on the outer side of the body 10, and a load-bearing device 75 for lifting a weight is provided in the load-bearing cavity 72. The load-bearing device 75 includes a fixed installation A placement plate 14 on the lower side wall of the load-bearing cavity 72. A protection case 15 is fixed on the upper side of the placement plate 14. A main motor fixedly connected to the upper side of the placement plate 14 is provided in the protection case 15. 16. A motor spline shaft 17 is dynamically connected to the main motor 16, a first bevel gear 18 is fixed on the motor spline shaft 17, and a second bevel tooth is rotatably connected to the inner left side wall of the protective casing 15. A second bevel gear 19 is fixed on the right side of the second bevel gear shaft 20 and meshes with the first bevel gear 18, and a second bevel gear 19 is provided on the left side of the second bevel gear 19 The first pulley 21 is fixedly connected to the shaft 20, and a large hydraulic cylinder 23 is fixed on the upper side of the placing plate 14. The large hydraulic cylinder 23 is power-connected. A pressure rod 24, a hydraulic plate 25 is fixed on the upper side of the hydraulic rod 24, a hydraulic column 27 is fixed on the upper side of the hydraulic plate 25, and a hydraulic spring is connected between the weight table 12 and the hydraulic plate 2526. Four supporting columns 28 distributed in a circular array are fixed on the upper side of the placing plate 14. A supporting spring 29 is connected between the placing plate 14 and the supporting platform 12, and the supporting platform 11 is provided therein. A transmission cavity 70 is provided with a drilling cavity 71 under the transmission cavity 70, a weight bearing device 77 is provided in the transmission cavity 70, and a weight supporting platform 12 is slidably connected to the upper side of the body 10. A wheeled cavity 74 is provided in the weight table 12, a sliding cavity 73 is provided on the upper side of the wheeled cavity 74, and a stabilizing device 76 for stabilizing the machine is provided on the outside of the body 10.


In addition, in one embodiment, a cylindrical groove is provided on the lower side of the supporting platform 12, and the motor spline shaft 17 extends upward through the protective housing 15 into the cylindrical groove of the supporting platform 12, so that The motor spline shaft 17 is rotatably connected on the lower side of the pulley cavity 74, and a second pulley 42 is fixed on the motor spline shaft 17 on the upper side, and the second side wall of the pulley cavity 74 is rotatably connected to the second side. A wheel axle 45, a second auxiliary wheel 44 is fixed on the second wheel axle 45, a second belt 43 is connected between the second auxiliary wheel 44 and the second pulley 42, and the sliding cavity 73 slides A top block 13 is connected. The top block 13 is provided with a large spiral hole 62 and a small spiral hole 63. The upper side of the second wheel shaft 45 is fixedly screwed with the top block 13 in the large spiral hole 62. A large spiral rod 46 is rotated, and a spline screw 47 is fixed on the upper side of the large spiral rod 46. A spiral column block capable of spirally rotating on the side wall of the small spiral hole 63 is slidably connected on the upper side of the spline screw 47. 48, a large drill bit 49 is fixed on the upper side of the spiral column block 48, so that when a roof accident occurs in the mine, the supporting platform 12 supports the falling roof and starts the main motor 16. Drive the motor spline shaft 17 to rotate, drive the first bevel gear 18, the second bevel gear 19, and the first pulley 21 to rotate, and the motor spline shaft 17 drives the first The second belt wheel 42 rotates, and the second belt 43 drives the second auxiliary wheel 44 to rotate, so that the large screw rod 46 rotates spirally with respect to the top block 13 so that the top block 13 and the inner block 13 The spline screw 47, the spiral column block 48, and the large drill bit 49 move upward, the top block 13 bears against the top plate, and the spline screw 47 is rotated by the large screw rod 46, so that the. The large drill bit 49 and the large drill bit 49 rotate, and the spiral column block 48 rotates spirally relative to the side wall of the small spiral hole 63, so that the spiral column block 48 and the large drill bit 49 move upward, and the large drill bit 49 Rotate up and drill into the top plate to fix the device and keep it vertical. At the same time, the weight table 12 presses down to contact the support column 28 and the hydraulic column 27. The support spring 29 and the hydraulic spring 26 cushion the pressure. To reduce the instantaneous impact, start the large hydraulic cylinder 23, and push the hydraulic rod 24 and the hydraulic pressure. The plate 25 and the hydraulic spring 26 are directed upward, and an upward force is applied to the weight table 12 to bear against the falling top plate.


In addition, in one embodiment, the stabilizing device 76 includes four connecting rods 30 that are fixedly installed in a circumferential array on the lower side of the supporting platform 12, and each of the connecting rods 30 is sleeved on the supporting weight outside. A compression spring 31 connected between the stage 12 and the placing plate 14. The connecting rod 30 extends downward through the placing plate 14 and enters the cavity 69. The connecting rod 30 may be in the placing plate 14. A sliding block 32 is fixed on the lower side of each of the connecting rods 30. A rotating shaft 33 is rotatably connected to the front and rear sides of the cavity 69. A connecting block 35 is hinged to the rotating shaft 33. A rotating shaft torsion spring 34 is connected between the connecting blocks 35. A support rod 37 is fixed on the connecting block 35. A convex block 36 is fixed on the lower side of the support rod 37. A friction block 38 is fixed on the side, an upper engaging block 39 is fixed on the inner side of the support rod 37, and four lifting rods 41 distributed in a circular array are fixed on the outer side of the supporting platform 12, each of the lifting rods 41 A lower engaging block 40 is fixed on the outer side, and the upper engaging block 39 is matched with the lower engaging block 40, so that when the supporting platform 12 is under The lifting rod 41 and the lower engaging block 40 are lowered, so that the upper engaging block 39 and the lower engaging block 40 are disengaged, and the torsion spring of the rotating shaft torsion spring 34 of the support rod 37 is wound around. The rotation shaft 33 rotates, the convex block 36 fits with the concave block 32, the friction block 38 rotates downward and contacts the ground, and at the same time, the compression spring 31 is compressed, and the compression spring 31 acts as a buffer, so that The connecting rod 30 and the concave block 32 descend downward, and the concave block 32 presses down the support rod 37 to make the friction block 38 press the ground, increase contact friction, stabilize the device, and can share Partial pressure.


In addition, in one embodiment, the load bearing device 77 includes a first wheel shaft 51 rotatably mounted on a right side wall of the transmission cavity 70, and a first auxiliary wheel 50 is fixed to the right side of the first wheel shaft 51. A third bevel gear 52 is fixed on the left side of the first wheel shaft 51. A first belt 22 is connected between the first auxiliary wheel 50 and the first pulley 21, the transmission cavity 70 and the drilling cavity. A fourth bevel shaft 54 is rotatably connected to the upper side wall of the transmission cavity 70 between 71, and a second gear meshing with the third bevel gear 52 is fixed on the fourth bevel shaft 54. 55. A first gear 59 is fixed on the lower side of the fourth bevel shaft 54. A symmetrical gear shaft 61 is rotatably connected to the upper side wall of the drilling cavity 71, and a spiral is fixed on each of the gear shafts 61. A spring 60. A fixed spline 56 is fixed on the lower side of the coil spring 60, and a long spiral rod 57 is rotatably connected to the fixed spline 56. The long spiral rod 57 is connected to the upper side wall of the drilling cavity 71. A fourth bevel gear 53 is connected between them, and a small drill bit 58 slidingly connected to the fixed spline 56 is fixed on the lower side of the long spiral rod 57 so that when the weight table 12 supports the top plate At the same time, the first belt 22 drives the first auxiliary wheel 50 and the first wheel shaft 51 to rotate, and the first wheel shaft 51 drives the third bevel gear 52, the fourth bevel gear 53, and the. The first gear 59 and the helical spring 60 rotate, and the long spiral rod 57 descends by helical rotation, which drives the small drill bit 58 to descend, while the fixed spline 56 drives the small drill bit 58 to rotate, the small drill bit 58 Drill down into the ground and stabilize the device.


In the initial state, the upper engagement block 39 hooks the lower engagement block 40, the support rod 37 is vertically outside the body 10, the main motor 16 and the large hydraulic cylinder 23 are not started, the top block 13 is in the support table 12, and the large drill bit 49 is in the top block 13.


When a roof accident occurs in the mine, the supporting platform 12 supports the falling roof, starts the main motor 16, and drives the motor spline shaft 17 to rotate, driving the first bevel gear 18, the second bevel gear 19, and the first pulley 21 Rotating, the motor spline shaft 17 simultaneously drives the second pulley 42 to rotate, and the second belt 43 drives the second auxiliary wheel 44 to rotate, so that the large screw rod 46 rotates spirally with respect to the top block 13 so that the top block 13 and the splines therein The screw 47, the screw column block 48 and the large drill bit 49 move upward, the top block 13 bears against the top plate, and the spline screw 47 rotates under the drive of the large screw rod 46, so that the large drill bit 49 and the large drill bit 49 rotate, and the spiral column block 48 faces The side wall of the small spiral hole 63 is spirally rotated, so that the spiral column block 48 and the large drill bit 49 move upward, the large drill bit 49 rotates and rises, and drills into the top plate to fix the device and keep it vertical. And hydraulic column 27, support spring 29 and hydraulic spring 26 to cushion the pressure, reduce the instant impact force, start the large hydraulic cylinder 23, push the hydraulic rod 24, the hydraulic plate 25 and the hydraulic spring 26 upward, and apply an upward force to the support table 12. Withstand the falling roof when the weight table 12 Lowering, the lifting rod 41 and the lower engaging block 40 are lowered, so that the upper engaging block 39 and the lower engaging block 40 are disengaged, and the torsion spring of the torsion spring 34 supporting the long shaft 37 rotates around the rotating shaft 33, the convex block 36 and the concave block 32 When fitted, the friction block 38 rotates downward and contacts the ground. At the same time, the compression spring 31 is compressed. The compression spring 31 acts as a buffer, which delays the connection rod 30 and the concave block 32 from descending. The concave block 32 presses down the long rod 37 to make the friction block. 38 applies pressure to the ground, increases contact friction, stabilizes the device, and can share part of the pressure. When the support platform 12 supports the top plate, the first belt 22 drives the first auxiliary wheel 50 and the first wheel shaft 51 to rotate. The axle 51 drives the third bevel gear 52, the fourth bevel gear 53, the first gear 59 and the helical spring 60 to rotate, and the long spiral rod 57 is helically rotated and lowered, and the small drill bit 58 is lowered. At the same time, the fixed spline 56 drives the small drill bit 58 to rotate. The small drill bit 58 drills down into the ground and stabilizes the device.


The beneficial effect of the present invention is that the device can withstand a falling roof when a roof accident occurs in a mine to prevent serious mine accidents and prevent serious personal injury, property damage and environmental damage. Among them, the load-bearing device can withstand The top plate is dropped, and the device can withstand the pressure of the top plate on the device through the hydraulic cylinder therein. At the same time, the device is fixed and the stabilizing device can keep the device in a stable state under the action of pressure, it will not fall, and share part of the pressure. The device can support the pressure on the roof of the mine and drill into the ground. Fix the device. The device can effectively reduce the harm caused by the roof accident, reduce accidents and various losses, and increase the safety during the production of the mine rate.


The above are only specific embodiments of the invention, but the scope of protection of the invention is not limited to this. Any changes or replacements that are not thought through without creative work should be covered by the scope of protection of the invention. Therefore, the protection scope of the invention shall be subject to the protection scope defined by the claims.

Claims
  • 1. A protection device for the occurrence of a mine roof fall includes a body, which is characterized in that: a load-bearing cavity is provided in the body, a load-bearing platform is fixed on the lower side of the body, and four circumferences are evenly distributed on the outside of the body A cavity, the weight-bearing cavity is provided with a weight-bearing device for lifting a heavy object; the weight supporting device includes a placing plate fixedly installed on the lower side wall of the load-bearing cavity. A protective shell is fixed on the side of the placing plate, and a protective shell is fixedly connected to the side of the placing plate. A main motor, the main motor is connected to a motor spline shaft, a first bevel gear is fixed on the motor spline shaft, and a second bevel gear shaft is rotatably connected to the left side wall of the protective housing, and the first A second bevel gear meshing with the first bevel gear is fixed on the right side of the second bevel gear shaft, and a first pulley fixedly connected to the second bevel gear shaft is provided on the left side of the second bevel gear. A large hydraulic cylinder is fixed on the side of the placing plate, and the large hydraulic cylinder is powered by a hydraulic rod. A hydraulic plate is fixed on the upper side of the hydraulic rod. A hydraulic column is fixed on the upper side of the hydraulic plate. A hydraulic spring is connected between the heavy platform and the hydraulic plate, and four supporting columns distributed in a circumferential array are fixed on the side of the placing plate, and a supporting spring is connected between the placing plate and the supporting platform;a transmission cavity is provided in the load bearing platform, a drilling cavity is provided on the lower side of the transmission cavity, a weight bearing device is provided in the transmission cavity, and a load bearing platform is slidably connected to the upper side of the body, and the support A wheel cavity is provided in the weight table, a sliding cavity is provided on the upper side of the wheel cavity, and a stabilizing device for stabilizing the machine is provided on the outside of the body.
  • 2. The protection device according to claim 1, wherein a cylindrical groove is provided on the lower side of the supporting platform, and the motor spline extends axially through the protection housing. Entering into the cylindrical groove of the load bearing platform, the motor spline shaft is rotatably connected at the lower side of the pulley cavity, and a second pulley is fixed at the upper side of the motor spline shaft. A second wheel shaft is rotatably connected to the side wall, a second auxiliary wheel is fixed on the second wheel shaft, a second belt is connected between the second auxiliary wheel and the second pulley, and the sliding cavity slides The top block is connected with a large spiral hole and a small spiral hole in the top block, and a large spiral rod that spirally rotates with the top block in the large spiral hole is fixed on the upper side of the second wheel shaft. A spline screw is fixed on the upper side of the large spiral rod, and a spiral column block that can be spirally rotated on the side wall of the small spiral hole is slidably connected on the upper side of the spline screw drill.
  • 3. The protection device for a mine roof fall according to claim 1, wherein the stabilizing device comprises four connecting rods fixedly installed in a circumferential array distributed on the lower side of the supporting platform. The outside of the connecting rod is sleeved with a compression spring connected between the weight platform and the placing plate. The connecting rod extends downward through the placing plate and enters the cavity. The placing plate slides up and down, and a concave block is fixed on the lower side of each of the connecting rods. A rotating shaft is rotatably connected to the front and back sides of the cavity, and a connecting block is hinged to the rotating shaft. A torsion spring is connected between the shafts. A support rod is fixed on the connection block, a convex block is fixed on the lower side of the support rod, and a friction block is fixed on the upper side of the support rod. An upper engaging block is fixed on the inner side of the rod, and four lifting rods distributed in a circular array are fixed on the outer side of the supporting platform. A lower engaging block is fixed on the outer side of each lifting rod, and the upper engaging block is connected with the lower engaging block. The fit block fits.
  • 4. The protection device for a mine roof fall according to claim 1, wherein the load-bearing device comprises a first wheel shaft rotatably mounted on a right wall of the transmission cavity, and a right side of the first wheel shaft A first auxiliary wheel is fixedly installed, and a third bevel gear is fixed on the left side of the first wheel shaft. A first belt is connected between the first auxiliary wheel and the first pulley, and the transmission cavity and the A fourth bevel shaft is rotatably connected to the upper side wall of the transmission cavity between the drilling cavities, and a second gear meshing with the third bevel gear is fixed on the fourth bevel shaft. A first gear is fixed on the lower side of the fourth bevel gear shaft, and a symmetrical gear shaft is rotatably connected to the upper side wall of the drilling cavity. Each of the gear shafts is fixed with a coil spring. A fixed spline is fixed on the side, and a long spiral rod is rotatably connected inside the fixed spline. A fourth bevel gear is connected between the long spiral rod and the upper side wall of the drilling cavity. A small drill is fixed on the side.
Priority Claims (1)
Number Date Country Kind
2019111217626 Nov 2019 CN national