CN113928803B

CN113928803B - A scalable sticky tape conveyer for high-efficient gangue separator

Info

Publication number: CN113928803B
Application number: CN202111204933.9A
Authority: CN
Inventors: 王爽; 李德永; 郭永存; 胡坤; 王鹏彧; 周军鹏; 马鑫
Original assignee: Anhui University of Science and Technology
Current assignee: Anhui University of Science and Technology
Priority date: 2021-10-15
Filing date: 2021-10-15
Publication date: 2023-05-16
Anticipated expiration: 2041-10-15
Also published as: CN113928803A

Abstract

The invention relates to the technical field of conveyors, in particular to a telescopic rubber belt conveyor for a high-efficiency coal gangue separation device, which comprises a shell, wherein a first belt wheel is rotationally connected to the inner wall of the shell, a second belt wheel is rotationally connected to the inner wall of the shell, a power belt wheel is rotationally connected to one side, far away from the second belt wheel, of the bottom of the inner wall of the shell, rectangular through holes are formed in the two sides of the shell, sliding rods are fixedly connected to the top and the bottom of each rectangular through hole, and a bearing seat is slidingly connected between the two sliding rods. By controlling the extension or shortening of the output shaft of the hydraulic cylinder and matching with the positive and negative rotation of the second motor, the power belt pulley is controlled to be close to or far away from the first belt pulley, the length of the adhesive tape which can be transported is shortened or increased, the flexibility is improved, the adhesive tape does not need to be cut off forcibly like the prior art, and the extra adhesive tape segments are mounted on the cut adhesive tape by using the button sewing clamp, so that the increase of the transportation distance of the adhesive tape is completed.

Description

A scalable sticky tape conveyer for high-efficient gangue separator

Technical Field

The invention relates to the technical field of conveyors, in particular to a telescopic rubber belt conveyor for a high-efficiency coal gangue separation device.

Background

The telescopic rubber belt conveyer is mainly used for conveying raw coal on underground stope face of coal mine, and can form a conveying flow of material from initial feeding point to final discharging point on a certain conveying line. The coal gangue screening device can be used for conveying broken materials and finished articles, coal gangue fragments are conveyed to the pneumatic screening device from one end and fall down, the pneumatic screening device is used for screening coal gangue and coal, and when the coal gangue screening device is used for conveying, the screening structure at the top of the adhesive tape can divide the coal gangue into a plurality of rows, so that the pneumatic screening device is convenient to screen.

At present, scalable sticky tape conveyer on the market often need cut off the sticky tape by force when adjusting the transportation distance of conveyer, utilize the button card to install extra sticky tape section to the sticky tape of being cut off, the transmission structure after the cooperation extension, thereby accomplish the increase of sticky tape transportation distance, troublesome operation, more button card needs to be wasted, and cause serious reduction to the life of sticky tape itself, the sticky tape is when transporting gangue, or transport a small amount of gangue through self tensioning, or the backup pad of different length is installed again to the bottom and is supported the sticky tape, thereby transport a large amount of gangue, but because sliding friction, the wearing and tearing to the sticky tape is great, therefore, need a scalable sticky tape conveyer for high-efficient gangue separator who is convenient for adjust transportation length, can not lead to the fact the destruction to the sticky tape during the regulation, the transport capacity obtains promoting, reduce the sticky tape wearing and tearing.

The above information disclosed in the background section is only for enhancement of understanding of the background of the disclosure and therefore it may include information that does not form the prior art that is already known to a person of ordinary skill in the art.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a telescopic rubber belt conveyor for a high-efficiency coal gangue separation device.

The technical scheme adopted for solving the technical problems is as follows: a scalable tape conveyor for high-efficient gangue separator, includes the casing, shells inner wall rotates and is connected with first band pulley, shells inner wall is located first band pulley bottom and rotates and be connected with the second band pulley, shells inner wall bottom is kept away from second band pulley one side and is rotated and be connected with the power band pulley, the inside rectangle through-hole that all opens of casing both sides, rectangle through-hole top and bottom all fixedly connected with slide bar, sliding connection has the bearing frame between two slide bars, rotate and be connected with the regulation band pulley between two bearing frames, the equal fixedly connected with pneumatic cylinder in casing outer wall both sides, pneumatic cylinder output shaft top fixedly connected with L shape pole, L shape pole is kept away from pneumatic cylinder one end and is run through the casing and with casing sliding connection, two L shape poles are kept away from the one end joint rotation of pneumatic cylinder and are connected with scissors fork mechanical structure, the utility model discloses a scissors fork mechanical structure, L shape pole one end is kept away from to cut fork mechanical structure rotates and is connected with two T shape pieces, it is equipped with the movable block to cut fork mechanical structure one end to keep away from L shape pole one end, the movable block is close to and opens two T shape grooves in scissors fork mechanical structure one side, T shape piece and T shape groove sliding connection, the casing is close to movable block one side and opens two standing grooves, the inside sliding connection of standing groove has the extension pole, extension pole and movable block fixed connection, movable block is kept away from extension pole one side fixedly connected with two limiting plates, rotate between the two limiting plates and be connected with the extension band pulley, regulating band pulley, power band pulley, first band pulley and second band pulley outside roll connection have the sticky tape, casing outer wall one side fixedly connected with first backup pad, first backup pad top fixedly connected with first motor, the top end of the output shaft of the first motor is fixedly connected with the power belt pulley.

Specifically speaking, the equal fixedly connected with locating piece of casing outer wall both sides, rotate between two locating pieces and be connected with the lead screw, lead screw one end runs through the locating piece, the outside threaded connection of lead screw has the drive block, drive block and bearing frame fixed connection, the equal fixedly connected with second backup pad of casing outer wall both sides, second backup pad top fixedly connected with second motor, second motor output shaft top fixedly connected with first gear, first gear top meshing has the second gear, second gear runs through locating piece one end fixed connection with the lead screw.

Specifically, the casing and extension rod top all open and are the first rectangular hole that linear array distributes, first rectangular hole both sides open threaded hole, the inside sliding connection of first rectangular hole has the T shaped plate, T shaped plate bottom surface and the laminating of casing top surface, the second rectangular hole has all been opened at T shaped plate both ends.

Specifically, the inside sliding connection of second rectangular hole has the rectangle piece, rectangle piece is kept away from rectangular hole one end fixedly connected with locating plate, the locating plate is inside to be run through to have two symmetrical distribution's cylinder hole, the inside sliding connection of cylinder hole has the bolt, bolt and screw hole threaded connection.

Specifically, a plurality of spherical holes distributed in a linear array are formed in the top of the T-shaped plate, balls are connected in the spherical holes in a rolling mode, and the balls are attached to the adhesive tape.

Specifically, the height of the T-shaped plate in sliding connection with the first rectangular hole on the extension rod is larger than that of the T-shaped plate in sliding connection with the first rectangular hole on the shell, and the top surface of the T-shaped plate installed on the extension rod and the top surface of the T-shaped plate installed on the shell are located on the same plane.

The invention has the beneficial effects that:

(1) According to the telescopic adhesive tape conveyor for the high-efficiency coal gangue separation device, the extension or shortening of the output shaft of the hydraulic cylinder is controlled, and the forward and backward rotation of the second motor is matched, so that the power belt wheel is controlled to be close to or far away from the first belt wheel, the transportation length of the adhesive tape is shortened or increased, the flexibility is improved, the adhesive tape is not required to be cut off forcibly in the prior art, the additional adhesive tape segments are mounted on the cut adhesive tape by using the button clips, the transportation distance of the adhesive tape is increased, the damage to the adhesive tape is reduced, and the service life of the adhesive tape is prolonged.

(2) According to the telescopic rubber belt conveyor for the high-efficiency coal gangue separation device, when the rubber belt is used for conveying coal gangue, the coal gangue drives the bottom surface of the rubber belt to be attached to the balls at the top of the T-shaped plate under the action of gravity, rolling friction is achieved, and meanwhile the balls support the rubber belt, so that the rubber belt can convey more coal gangue without breaking.

(3) According to the telescopic rubber belt conveyor for the high-efficiency coal gangue separation device, the output shaft of the hydraulic cylinder is shortened, and the second motor rotates, so that the moving plate drives the extension rod to extend out of the shell, the T-shaped plate can be arranged on the shell and the extension rod at the moment, different numbers of T-shaped plates can be arranged to support the rubber belt under the condition that the rubber belt conveying distance is increased, and the stability and the carrying amount during conveying are ensured.

Drawings

For a clearer description of embodiments of the present application or of the solutions in the prior art, the drawings that are needed in the embodiments will be briefly described, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and that other drawings can be obtained according to these drawings by a person having ordinary skill in the art.

FIG. 1 is a schematic view of the overall structure provided by the present invention;

FIG. 2 is a first view, partially in section, provided by the present invention;

FIG. 3 is a second view, partially in section, provided by the present invention;

FIG. 4 is a third view, partially in section, provided by the present invention;

FIG. 5 is a schematic diagram of an extension rod and a T-shaped plate at the top of the housing according to the present invention;

fig. 6 is an enlarged view of the structure of the portion a in fig. 4 according to the present invention.

In the figure: 1. the device comprises a shell, 2, a first belt wheel, 3, a second belt wheel, 4, a power belt wheel, 5, a rectangular through hole, 6, a sliding rod, 7, a bearing seat, 8, an adjusting belt wheel, 9, a hydraulic cylinder, 10, an L-shaped rod, 11, a scissor-fork type mechanical structure, 12, a T-shaped block, 13, a moving block, 14, a T-shaped groove, 15, a placing groove, 16, an extension rod, 17, a limiting plate, 18, an extension belt wheel, 19, an adhesive tape, 20, a first supporting plate, 21, a first motor, 22, a positioning block, 23, a lead screw, 24, a transmission block, 25, a second supporting plate, 26, a second motor, 27, a first gear, 28, a second gear, 29, a first rectangular hole, 30, a threaded hole, 31, a T-shaped plate, 32, a second rectangular hole, 33, a rectangular block, 34, a positioning plate, 35, a cylindrical hole, 36, a spherical hole, 37 and a ball.

Detailed Description

The invention is further described in connection with the following detailed description in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the invention easy to understand.

As shown in fig. 1-6, the telescopic rubber belt conveyor for the efficient coal gangue separating device comprises a shell 1, wherein the inner wall of the shell 1 is rotationally connected with a first belt pulley 2, the inner wall of the shell 1 is rotationally connected with a second belt pulley 3 at the bottom of the first belt pulley 2, one side, far away from the second belt pulley 3, of the bottom of the inner wall of the shell 1 is rotationally connected with a power belt pulley 4, rectangular through holes 5 are formed in the two sides of the shell 1, sliding rods 6 are fixedly connected to the top and the bottom of each rectangular through hole 5, bearing blocks 7 are slidingly connected between the two sliding rods 6, an adjusting belt pulley 8 is rotationally connected between the two bearing blocks 7, hydraulic cylinders 9 are fixedly connected to the two sides of the outer wall of the shell 1, an L-shaped rod 10 is fixedly connected to the top end of an output shaft of the hydraulic cylinder 9, one end, far away from the hydraulic cylinder 9, of the L-shaped rod 10 penetrates through the shell 1 and is slidingly connected with the shell 1, the one end that hydraulic cylinder 9 was kept away from to two L shape poles 10 rotates jointly and is connected with scissors fork mechanical structure 11, scissors fork mechanical structure 11 is kept away from L shape pole 10 one end and rotates and be connected with two T shape pieces 12, scissors fork mechanical structure 11 is kept away from L shape pole 10 one end and is equipped with movable block 13, movable block 13 is close to scissors fork mechanical structure 11 one side and opens two T-shaped groove 14, T shape piece 12 and T-shaped groove 14 sliding connection, casing 1 is close to movable block 13 one side and opens two standing grooves 15, inside sliding connection of standing groove 15 has extension pole 16, extension pole 16 and movable block 13 fixed connection, movable block 13 is kept away from extension pole 16 one side fixedly connected with two limiting plates 17, rotate between two limiting plates 17 and be connected with extension band pulley 18, regulation band pulley 8, the extension band pulley 15 is opened The outside roll connection of power band pulley 4, first band pulley 2 and second band pulley 3 has sticky tape 19, first backup pad 20 of casing 1 outer wall one side fixedly connected with, first backup pad 20 top fixedly connected with first motor 21, first motor 21 output shaft top and power band pulley 4 fixed connection shorten through pneumatic cylinder 9 output shaft to drive L shape pole 10 and slide to casing 1 inside, L shape pole 10 drives and cuts fork mechanical structure 11 motion, cut fork mechanical structure 11 extension, thereby drive movable block 13 to keeping away from and cut fork mechanical structure 11 direction and remove, movable block 13 drives extension pole 16 and outwards slide out from the standing groove 15, simultaneously bearing frame 7 drives the regulation band pulley 8 and slides towards being close to movable block 13 direction in rectangular through-hole 5, extension band pulley 18 keeps away from first band pulley 2 under the drive of movable block 13 this moment, the distance between first band pulley 2 and the extension band pulley 18 is prolonged this moment, distance between first band pulley 2 and the power band pulley 4 is shortened, thereby make the length that this telescopic machine can transport, during operation, first motor 21 drives power band pulley 4 and rotates, power band pulley 4 drives the movement 19 to drop the sticky tape 19, thereby the coal tape that the top is transported to one end to the sticky tape 18.

Specifically, the positioning blocks 22 are fixedly connected to two sides of the outer wall of the shell 1, the lead screw 23 is rotatably connected between the two positioning blocks 22, one end of the lead screw 23 penetrates through the positioning blocks 22, the transmission block 24 is connected to the outside of the lead screw 23 in a threaded manner, the transmission block 24 is fixedly connected with the bearing seat 7, the second supporting plates 25 are fixedly connected to two sides of the outer wall of the shell 1, the second motor 26 is fixedly connected to the top of the second supporting plate 25, the first gear 27 is fixedly connected to the top of the output shaft of the second motor 26, the second gear 28 is meshed with the top of the first gear 27, the second gear 28 and the lead screw 23 penetrate through one end of the positioning block 22 and are fixedly connected, the first gear 27 is driven to rotate through the second motor 26, the first gear 27 drives the second gear 28 to rotate, the second gear 28 drives the lead screw 23 to rotate, the transmission block 24 moves on the lead screw 23, and the transmission block 24 drives the bearing seat 7 to slide in the rectangular through hole 5, thereby changing the distance between the adjusting belt pulley 8 and the power belt pulley 4, and the belt pulley 18 is matched and the length of the coal gangue to be transported is changed.

Specifically, the casing 1 and extension rod 16 top all open and are the first rectangular hole 29 that linear array distributes, threaded hole 30 is opened to first rectangular hole 29 both sides, the inside sliding connection of first rectangular hole 29 has T shaped plate 31, T shaped plate 31 bottom surface and casing 1 top surface laminating, T shaped plate 31 both ends all open and are had second rectangular hole 32, through inserting T shaped plate 31 bottom in first rectangular hole 29, spacing T shaped plate 31 at casing 1 top, support sticky tape 19, prevent sticky tape 19 at the gravity sagging of gangue to lead to sticky tape 19 to burst, make the weight of the gangue that sticky tape 19 can transport obtain promoting.

Specifically, the second rectangular hole 32 is internally slidably connected with a rectangular block 33, one end, away from the rectangular hole, of the rectangular block 33 is fixedly connected with a positioning plate 34, two symmetrically distributed cylindrical holes 35 are formed in the positioning plate 34 in a penetrating manner, bolts are slidably connected with the cylindrical holes 35 in the threaded manner and are in threaded connection with the threaded holes 30, the rectangular block 33 is inserted into the second rectangular hole 32, and then the positioning plate 34 is fixed onto the shell 1 through the bolts, so that the T-shaped plate 31 is fixed onto the shell 1, and the T-shaped plate 31 is convenient to assemble and disassemble.

Specifically, the top of the T-shaped plate 31 is provided with a plurality of spherical holes 36 distributed in a linear array, the inside of the spherical holes 36 is in rolling connection with balls 37, the balls 37 are attached to the adhesive tape 19, and the balls 37 are in rolling connection with the top of the T-shaped plate 31, so that when the adhesive tape 19 is in contact with the T-shaped plate 31, sliding connection is changed into rolling connection, friction of the adhesive tape 19 is reduced, and the service life of the adhesive tape 19 is prolonged.

Specifically, the height of the T-shaped plate 31 slidingly connected with the first rectangular hole 29 on the extension rod 16 is greater than the height of the T-shaped plate 31 slidingly connected with the first rectangular hole 29 on the housing 1, the top surface of the T-shaped plate 31 mounted on the extension rod 16 and the top surface of the T-shaped plate 31 mounted on the housing 1 are in the same plane, and the top surfaces are in the same plane due to the difference in height between the T-shaped plate 31 on the extension rod 16 and the T-shaped plate 31 on the housing 1, so that the adhesive tape 19 always fits with the top surface of the T-shaped plate 31 after the extension pulley 18 extends.

The working principle of the invention is as follows: and (3) adjusting: respectively starting the hydraulic cylinder 9 and the second motor 26, so that the scissor type mechanical structure 11 drives the extension belt pulley 18 to be far away from the first belt pulley 2, and the adjustment belt pulley 8 is close to the power belt pulley 4, so that the transportation length of the adhesive tape 19 positioned at the top of the shell 1 is increased, then the corresponding T-shaped plate 31 is placed on the shell 1 and the extension rod 16, the positioning plate 34 is mounted on the shell 1 by bolts, and the T-shaped plate 31 is mounted, and at the moment, the adhesive tape 19 is attached to the top surface of the T-shaped plate 31;

the working steps are as follows: the coal gangue continuously falls onto the adhesive tape 19, the first motor 21 is started, the first motor 21 drives the power belt pulley 4 to roll, the power belt pulley 4 drives the adhesive tape 19, the adhesive tape 19 drives the ball 37 to rotate, the adhesive tape 19 conveys the coal gangue at the top to one end of the extension belt pulley 18 to fall, so that the coal gangue is conveyed, the coal gangue is separated into a plurality of rows to fall by matching with a screening structure at the top, and then the coal gangue is screened by matching with a pneumatic screening device;

by controlling the extension or shortening of the output shaft of the hydraulic cylinder 9 and matching with the forward and reverse rotation of the second motor 26, the power belt wheel 4 is controlled to be close to or far away from the first belt wheel 2, so that the transportation length of the adhesive tape 19 is shortened or increased, the flexibility is improved, the adhesive tape 19 is not required to be forcibly cut off like the prior art, the extra adhesive tape 19 fragments are mounted on the cut adhesive tape 19 by using the button clips, the transportation distance of the adhesive tape 19 is increased, the damage to the adhesive tape 19 is reduced, and the service life of the adhesive tape 19 is prolonged;

when the adhesive tape 19 is used for transporting the gangue, the gangue drives the bottom surface of the adhesive tape 19 to be attached to the ball 37 at the top of the T-shaped plate 31 under the action of gravity, rolling friction is realized, and meanwhile, the ball 37 supports the adhesive tape 19, so that the adhesive tape 19 can transport more gangue without fracture;

the output shaft through pneumatic cylinder 9 shortens while second motor 26 rotates for the movable plate drives extension rod 16 and stretches out in from casing 1, can install T shaped plate 31 on casing 1 and extension rod 16 this moment, make sticky tape 19 transportation distance under the circumstances of increasing, can install T shaped plate 31 of different quantity and support sticky tape 19, stability and the carrying capacity when guaranteeing to transport, this embodiment has specifically solved scalable sticky tape 19 conveyer that exists among the prior art when adjusting the transportation distance of conveyer, often need strongly cut off sticky tape 19, utilize the button card to install extra sticky tape 19 section on cut sticky tape 19, the transmission structure after the cooperation extension, thereby accomplish the increase of sticky tape 19 transportation distance, troublesome operation, need extravagant more button card, and cause serious reduction to the life of sticky tape 19 itself, simultaneously sticky tape 19 is when transporting gangue, or support the sticky tape 19 through the support of the tensioning transportation a small amount of gangue of self, or the backup pad of the different length of bottom installation again, thereby transport a large amount of coal gangue, but because slip friction damage is the friction gangue, wear and tear the device that need not be convenient for adjusting the sticky tape 19 is high, can be used for the transportation device to the high-efficient wear and tear the sticky tape 19 can be reduced when adjusting the transportation length of the sticky tape 19.

While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that modifications may be made to the described embodiments in various different ways without departing from the spirit and scope of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive of the scope of the invention, which is defined by the appended claims.

Claims

1. A scalable sticky tape conveyer for high-efficient gangue separator, its characterized in that: including casing (1), casing (1) inner wall rotation is connected with first band pulley (2), casing (1) inner wall is located first band pulley (2) bottom rotation and is connected with second band pulley (3), second band pulley (3) one side rotation is kept away from to casing (1) inner wall bottom is connected with power band pulley (4), rectangle through-hole (5) are all opened to casing (1) both sides inside, rectangle through-hole (5) top and bottom equal fixedly connected with slide bar (6), sliding connection has bearing frame (7) between two slide bar (6), rotation is connected with regulation band pulley (8) between two bearing frames (7), casing (1) outer wall both sides equal fixedly connected with pneumatic cylinder (9), pneumatic cylinder (9) output shaft top fixedly connected with L shape pole (10), L shape pole (10) one end run through casing (1) and with casing (1) sliding connection, two L shape poles (10) are kept away from the joint rotation of one end of pneumatic cylinder (9) and are connected with fork mechanical fork structure (11), two mechanical fork structure (11) are kept away from (12) one end and are kept away from mechanical fork structure (13), two T-shaped grooves (14) are formed in one side, close to the scissor type mechanical structure (11), of the moving block (13), the T-shaped block (12) is in sliding connection with the T-shaped grooves (14), two placing grooves (15) are formed in one side, close to the moving block (13), of the shell (1), an extension rod (16) is connected inside the placing grooves (15) in a sliding mode, the extension rod (16) is fixedly connected with the moving block (13), two limiting plates (17) are fixedly connected to one side, far away from the extension rod (16), of the moving block (13), an extension belt wheel (18) is connected between the two limiting plates (17) in a rotating mode, an adhesive tape (19) is connected to the outer portion of the extension belt wheel (18), the adjusting belt wheel (8), the outer portion of the power belt wheel (4), the first belt wheel (2) and the outer portion of the second belt wheel (3), a first supporting plate (20) is fixedly connected to one side of the outer wall of the shell (1), a first motor (21) is fixedly connected to the top of the first supporting plate (20), and the top end of an output shaft of the first motor (21) is fixedly connected with the power belt wheel (4).

The novel telescopic device is characterized in that first rectangular holes (29) distributed in a linear array are formed in the tops of the shell (1) and the extension rod (16), threaded holes (30) are formed in two sides of the first rectangular holes (29), a T-shaped plate (31) is connected inside the first rectangular holes (29) in a sliding mode, the bottom surface of the T-shaped plate (31) is attached to the top surface of the shell (1), and second rectangular holes (32) are formed in two ends of the T-shaped plate (31);

a plurality of spherical holes (36) distributed in a linear array are formed in the top of the T-shaped plate (31), balls (37) are connected inside the spherical holes (36) in a rolling mode, and the balls (37) are attached to the adhesive tape (19).

2. The telescopic rubber belt conveyor for the efficient coal gangue separation device according to claim 1, wherein: the utility model discloses a motor, including casing (1) outer wall, casing (1) outer wall both sides all fixedly connected with locating piece (22), rotate between two locating pieces (22) and be connected with lead screw (23), lead screw (23) one end runs through locating piece (22), lead screw (23) outside threaded connection has driving block (24), driving block (24) and bearing frame (7) fixed connection, the equal fixedly connected with second backup pad (25) in casing (1) outer wall both sides, second backup pad (25) top fixedly connected with second motor (26), second motor (26) output shaft top fixedly connected with first gear (27), first gear (27) top meshing has second gear (28), second gear (28) and lead screw (23) run through locating piece (22) one end fixed connection.

3. The telescopic rubber belt conveyor for the efficient coal gangue separation device according to claim 1, wherein: the inside sliding connection of second rectangular hole (32) has rectangle piece (33), rectangle piece (33) are kept away from rectangular hole one end fixedly connected with locating plate (34), inside run through of locating plate (34) has two symmetrically distributed cylinder holes (35), inside sliding connection of cylinder hole (35) has the bolt, bolt and screw hole (30) threaded connection.

4. The telescopic rubber belt conveyor for the efficient coal gangue separation device according to claim 1, wherein: the height of the T-shaped plate (31) which is in sliding connection with the first rectangular hole (29) on the extension rod (16) is larger than the height of the T-shaped plate (31) which is in sliding connection with the first rectangular hole (29) on the shell (1), and the top surface of the T-shaped plate (31) arranged on the extension rod (16) and the top surface of the T-shaped plate (31) arranged on the shell (1) are positioned on the same plane.