CN115302606A

CN115302606A - Hollow brick press forming device

Info

Publication number: CN115302606A
Application number: CN202211030385.7A
Authority: CN
Inventors: 马娟
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-08-26
Filing date: 2022-08-26
Publication date: 2022-11-08

Abstract

The invention relates to the technical field of hollow brick preparation, and discloses a hollow brick press forming device which comprises a fixing frame, wherein an installation table and a lifting mechanism are installed inside the fixing frame, a placing plate is placed on the upper end surface of the installation table, a mold is installed on the upper surface of the placing plate, a lower pressing piece is installed on the upper side surface of the fixing frame, a forming piece is installed at the end part of an output rod of the lower pressing piece, a fixing rod is installed on the upper surface of the lifting mechanism and is divided into a longitudinal rod and a transverse rod, the longitudinal rod and the lifting mechanism are fixedly connected, a transverse rod is installed at the upper end of the longitudinal rod, a fixing plate is fixedly installed at one end of the transverse rod, and a discharging piece is installed at the lower end of the fixing plate. According to the invention, through the arrangement of the fixing rod, the fixing plate and the discharging piece, the discharging piece can move downwards to push the rough blank in the inner cavity of the mold, so that the influence of the friction force between the mold and the rough blank on the downward movement of the rough blank is reduced, and the probability of corner defect of the rough blank is reduced.

Description

Hollow brick press forming device

Technical Field

The invention relates to the technical field of hollow brick preparation, in particular to a hollow brick pressing and forming device.

Background

The hollow brick is a main material of a wall body commonly used in the building industry, and has the advantages of light weight, less consumption of raw materials and the like, wherein in the preparation process of the hollow brick, a press forming device is required to convert a mixed material with certain water content into a hollow brick rough blank, so that the implementation of the subsequent process is facilitated.

When some existing hollow brick press forming devices are used, firstly, a placing plate is placed on the surface of an installation table, then, a mold is made to move downwards, the bottom surface of the mold is tightly attached to the upper surface of the placing plate, then, a mixed material with a certain water content is input into an inner cavity of the mold, then, a formed part moves downwards and extends into the mixed material, the material right below a pressure part is made to be discharged out of the mold through a through hole of the placing plate, then, the formed part stops for a period of time after moving downwards to a limit position, then, the formed part moves upwards to reset, the central position of the material is hollow, finally, the mold moves upwards, the hollow brick rough blank is made to be separated from the mold, through the actions, the press forming of the hollow brick rough blank is completed, in the process of moving upwards, the hollow brick rough blank is separated from the mold only through the gravity of the hollow brick rough blank, the position where the rough blank is contacted with the inner wall of the mold is easily influenced by the friction force between the rough blank and the mold, the rough blank is easily broken corner phenomenon after the blank is separated from the mold, and the quality of the hollow brick is influenced.

Disclosure of Invention

Aiming at the defects of the existing hollow brick pressing and forming device in the background technology in the using process, the invention provides the hollow brick pressing and forming device which has the advantages of reducing the probability of corner defect of a rough blank and improving the quality of the hollow brick, and solves the technical problems in the background technology.

The invention provides the following technical scheme: the utility model provides an air brick press forming device, includes the mount, the inside bottom surface fixed mounting of mount has mount table and lifting mechanism, the up end of mount table is placed inside and is run through the board of placing of seting up the clout hole, the last surface mounting who places the board has the mould, the output lever of lifting mechanism and the bottom surface formation fixed connection that the mould edge stretched out the end, the last side fixed mounting of mount has the output lever to stretch into the inside lower pressure member of mount, the tip fixed mounting of lower pressure member output lever has the formed part, the last surface fixed mounting of lifting mechanism cylinder body has the dead lever, the dead lever divide into longitudinal rod and transverse rod, the lower extreme of longitudinal rod forms fixed connection with the upper surface of lifting mechanism cylinder body, the upper end department fixed mounting of longitudinal rod has the transverse rod, the transverse rod has the fixed plate towards the one end fixed mounting of formed part, the lower extreme fixed mounting of fixed plate has the unloading piece, the outside of unloading piece forms sliding connection with the inner wall body of mould.

Preferably, the upper side surface of the unloading piece is arranged in an inclined surface structure.

Preferably, a liquid cavity is formed in the longitudinal rod, a driving magnet is fixedly mounted at a position, close to the liquid cavity, inside the die, a driven piston is movably mounted in the liquid cavity and is in the same horizontal state with the driving magnet, a driven magnet which is opposite in polarity to the driving magnet is fixedly mounted inside the driven piston, a liquid medium is filled in a cavity, located above the driven piston, in the liquid cavity, and a liquid guide hole is formed in the transverse rod and the fixing plate.

Preferably, the lift chamber has been seted up to the inside of fixed plate, sealed movable mounting has a lifter plate No. one in the inner chamber in lift chamber, the drain hole is arranged in the intercommunication sap cavity in the cavity that lies in slave piston top position and the cavity that lies in lifter plate top position in the lift chamber, no. two lifter plates are installed to the below position of a lifter plate, no. two lifter plates form sealed swing joint with the lift chamber, one side position fixed mounting of No. two lifter plate lower surfaces has the rack, install the section of thick bamboo that rotates in the cavity that lies in No. two lifter plate below positions in the lift chamber, the leading flank fixed mounting of section of thick bamboo that rotates has the gear of being connected with the rack formation meshing, the leading flank fixed mounting of gear has the pivot, the opposite side of pivot forms to rotate with the leading flank inner wall in lift chamber and is connected.

Preferably, the eccentric articulated company of trailing flank who rotates a section of thick bamboo has the board, slidable mounting has the striking piece that the downside contacted unloads the material piece in the cavity that lies in a section of thick bamboo lower position in the lift intracavity, the last side of striking piece forms articulated fixedly with the lower terminal surface who links the board.

Preferably, the inside fixed mounting of plate body of formed part has a magnetic part, the through-hole has been seted up in the inside run-through of No. two lifter plates, the inside fixed mounting of No. two lifter plates has the magnetic part No. two that is heteropolar attracting mutually with a magnetic part.

Preferably, an elastic part is fixedly mounted between the upper surface of the second lifting plate and the lower surface of the first lifting plate together, so as to drive the second lifting plate to reset.

Preferably, the inside of striking piece is seted up and is the logical groove of perpendicular correspondence with the rack, the cross-sectional area that leads to the groove is greater than the cross-sectional area of rack, magnetic attraction between driving magnet and the driven magnet is greater than the magnetic attraction between a magnetic part and No. two magnetic parts, magnetic attraction between a magnetic part and No. two magnetic parts is greater than the elasticity of elastic component, the number of teeth of the gear of rack is greater than the number of teeth of gear.

The invention has the following beneficial effects:

1. according to the invention, through the arrangement of the fixed rod, the fixed plate and the discharging piece, in the process of moving the die upwards, the fixed rod and the fixed plate can fix the discharging piece, so that the discharging piece and the upward-moving die move relatively, and further the discharging piece extends into the inner cavity of the die, and then the discharging piece moves downwards to push the rough blank in the inner cavity of the die along with the continuous upward movement of the die, thereby reducing the influence of the friction force between the die and the rough blank on the downward movement of the rough blank and reducing the probability of corner missing of the rough blank.

2. According to the invention, through the arrangement of the driven piston and the first lifting plate, in the process of moving the die upwards, the driven piston synchronously moves upwards, so that the first lifting plate moves downwards, and the rack is driven to be in meshing transmission with the gear, so that the impact piece impacts the unloading piece in a reciprocating manner to cause the unloading piece to vibrate, and through the vibration, the adhesion between the rough blank and the unloading piece is avoided, thereby further reducing the probability of corner defect of the rough blank.

3. According to the invention, through the arrangement of the discharging part and the second lifting plate, in the process that the formed part extends into the material, the second lifting plate synchronously moves downwards, so that the striking part impacts the discharging part in a reciprocating manner, and the discharging part vibrates, at the moment, the material in the die is extruded by the formed part, so that a small amount of material moves upwards and enters the inclined plane of the discharging part, through the vibration, the material particles contacted with the discharging part become tight, and further more materials can be contained in the die, meanwhile, the material entering the inclined plane falls back into the die, through the action, the probability of irregular protrusions formed on the surface of a rough blank by the material moving upwards is reduced, and meanwhile, the quality of the hollow brick is improved.

4. According to the invention, through the arrangement of the elastic piece and the second lifting plate, after the formed piece completely extends into the material, the elastic piece drives the second lifting plate to move upwards for resetting, so that the discharging piece continuously generates vibration, the accommodating capacity of the die is further improved, and the probability that the material moving upwards forms irregular bulges on the surface of the rough blank is further reduced.

Drawings

FIG. 1 is a schematic view of the internal structure of the fixing frame of the present invention;

FIG. 2 is an enlarged view of a portion of the structure A of FIG. 1 according to the present invention;

FIG. 3 is a schematic view of the internal structure of the fixing rod and the fixing plate according to the present invention;

FIG. 4 is a schematic view of a rotary cylinder of the present invention.

In the figure: 1. a fixed mount; 2. a mold; 3. a lifting mechanism; 4. a push-down member; 5. a forming member; 6. a first magnetic member; 7. a fixing rod; 8. a liquid chamber; 9. a driving magnet; 10. a slave piston; 11. a driven magnet; 12. a drain hole; 13. a fixing plate; 14. unloading the material; 15. a lifting cavity; 16. a first lifting plate; 17. a second lifting plate; 18. an elastic member; 19. a rack; 20. a rotating cylinder; 21. a gear; 22. a second magnetic member; 23. connecting plates; 24. a striker.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, a hollow brick press forming device comprises a fixing frame 1, a mounting table is welded at the middle position of the inner bottom surface of the fixing frame 1, a placing plate is placed on the upper end surface of the mounting table, a residual material hole is longitudinally formed in the middle position of the inner portion of the placing plate in a penetrating manner, a mold 2 is installed on the upper surface of the placing plate, lifting mechanisms 3 are welded at the two side positions of the inner bottom surface of the fixing frame 1 (the lifting mechanisms 3 are the combination of a hydraulic cylinder and an output rod in the prior art), the output rod of the lifting mechanism 3 is welded and fixed with the bottom surface of the edge extending end of the mold 2, a lower pressing member 4 is welded on the upper side surface of the fixing frame 1 (the lower pressing member 4 is the combination of the hydraulic cylinder and the output rod in the prior art), the output rod of the lower pressing member 4 extends into the inner portion of the fixing frame 1, a formed part 5 is welded on the end portion of the output rod of the lower pressing member 4, the cross-sectional area of the upper end of the formed part 5 is smaller than the residual material hole, a fixed rod 7 is welded on the upper surface of the cylinder body of the lifting mechanism 3, the fixed rod 7 which is divided into a longitudinal rod and a transverse rod, the longitudinal rod, the lower end of the fixed rod and the fixed rod 14, the blank 2, the blank is welded with the blank 2, the blank is pushed by the blank by the die, the blank 14, the blank 2, and the blank 14, the blank is moved upwards moving mechanism in the blank moving mechanism, and moved upwards under the action of the blank in the blank moving mechanism 2, and then the blank is separated from the inner cavity of the mould 2, so that the influence of the friction force between the mould 2 and the blank on the downward movement of the blank is reduced, and the probability of corner defect of the blank is reduced.

The upper side surface of the discharging part 14 is arranged in an inclined surface structure, the lower end of the fixing plate 13 is welded and fixed with the inclined surface, and the material remaining on the inclined surface is easy to move along the inclined surface direction when being subjected to subsequent vibration force through the arrangement of the inclined surface structure, so that the subsequent material supplementing function is realized.

Referring to fig. 1 and 3, a liquid cavity 8 is formed inside the longitudinal rod, a driving magnet 9 is fixedly installed at a position inside the mold 2 close to the liquid cavity 8, a driven piston 10 is installed in the liquid cavity 8 in a sealing and sliding manner (the connection is similar to the connection between an oil cylinder and a piston in the prior art), the driven piston 10 and the driving magnet 9 are in the same horizontal state, a driven magnet 11 is fixedly installed inside the driven piston 10, the driven magnet 11 and the driving magnet 9 are arranged in a heteropolar attraction manner, an air release hole is formed inside the longitudinal rod and below the driven piston 10, the air release hole communicates with the external environment and a cavity below the driven piston 10 in the liquid cavity 8, a liquid medium (such as water) is filled in the cavity above the driven piston 10 in the liquid cavity 8, a liquid guide hole 12 is formed inside the transverse rod and the fixing plate 13 together, when the mold 2 moves upward, the driving magnet 9 inside the mold 2 attracts the driven magnet 11 inside the driven piston 10, so that the driven piston 10 extrudes the liquid medium in the liquid cavity 8 into the liquid guide hole 12, thereby providing a power source for realizing subsequent functions.

Referring to fig. 1 and 2, a lifting cavity 15 is formed in a fixed plate 13, a first lifting plate 16 is slidably and hermetically mounted in an inner cavity of the lifting cavity 15, one side of a liquid guide hole 12 is communicated with a cavity in the liquid cavity 8 above a driven piston 10, the other side of the liquid guide hole 12 is communicated with a cavity in the lifting cavity 15 above the first lifting plate 16, a second lifting plate 17 is mounted below the first lifting plate 16, the second lifting plate 17 is slidably and hermetically connected with the lifting cavity 15, a rack 19 is welded on the right side of the lower surface of the second lifting plate 17, a rotary cylinder 20 is mounted in a cavity in the lifting cavity 15 below the second lifting plate 17, a gear 21 is welded on the front side of the rotary cylinder 20, the gear 21 is in meshed connection with the rack 19, a rotary shaft is welded on the front side of the gear 21, the other side of the rotary shaft is rotatably connected with the inner wall of the front side of the lifting cavity 15, a liquid medium in the liquid guide hole 12 enters the lifting cavity 15, and pushes the first lifting plate 16 to move down with the second lifting plate 17, so that the rack 19 is meshed with the gear, and the rotary cylinder 20 is conveniently moved back and forth.

Referring to fig. 3 and 4, the rear side surface of the rotary drum 20 is eccentrically hinged with a connecting plate 23, an impact piece 24 is slidably mounted in a cavity located below the rotary drum 20 in the lifting cavity 15, the middle position of the upper side surface of the impact piece 24 is hinged and fixed with the lower end surface of the connecting plate 23, the lower side surface of the impact piece 24 contacts with the inclined surface of the discharging piece 14, when the rotary drum 20 rotates, the connecting plate 23 drives the impact piece 24 to reciprocate to move up and down, so that the impact piece 24 reciprocally impacts the discharging piece 14 to cause the discharging piece 14 to vibrate, and the rough blank is prevented from being adhered to the bottom surface of the discharging piece 14 through the vibration, and the probability of the corner missing phenomenon of the rough blank is further reduced.

The first magnetic part 6 is fixed inside the plate body of the forming part 5, a through hole is longitudinally formed in the second lifting plate 17 in a penetrating mode, the second magnetic part 22 is fixedly installed inside the second lifting plate 17, the second magnetic part 22 and the first magnetic part 6 are arranged in a heteropolar attraction mode, in the process that the forming part 5 extends downwards into materials, when the first magnetic part 6 inside the forming part 5 is close to the second magnetic part 22 inside the second lifting plate 17, the second lifting plate 17 is driven to synchronously move downwards under the action of magnetic force, the rack 19 and the gear 21 form meshing transmission, the rotating cylinder 20 drives the impact part 24 to impact the unloading part 14 in a reciprocating mode, the unloading part 14 generates vibration, at the moment, materials in the die 2 are extruded by the forming part 5, a small amount of materials move upwards and enter the inclined plane of the unloading part 14, through the vibration, material particles contacting the bottom surface of the unloading part 14 become compact, further more materials can be contained in the die 2, the materials enter the inclined plane and then fall back into the die 2, the rough movement and the probability of the blank is reduced, and the quality of hollow bricks is improved.

An elastic part 18 is fixedly arranged on the upper surface of the second lifting plate 17, the upper end of the elastic part 18 is fixedly connected with the lower surface of the first lifting plate 16, when the second lifting plate 17 moves downwards under the action of magnetic attraction, the elastic part 18 can be stretched, and then when the formed part 5 moves downwards to the limit position, the first magnetic part 6 in the formed part 5 does not attract the second magnetic part 22 in the second lifting plate 17 any more, so that the elastic part 18 releases the elastic force and drives the second lifting plate 17 to move upwards and reset, the rack 19 further drives the gear 21 to rotate, the unloading part 14 continues to vibrate, the accommodating capacity of the mold 2 is further improved, and the probability that the upwards-moved materials form irregular bulges on the surface of the rough blank is reduced.

Logical groove has been seted up to striking piece 24's inside, it corresponds the setting perpendicularly to lead to groove and rack 19, the cross-sectional area that leads to the groove is greater than rack 19's cross-sectional area, magnetic attraction between driving magnet 9 and driven magnet 11 is greater than the magnetic attraction between magnetic part 6 and No. two magnetic parts 22, magnetic attraction between magnetic part 6 and No. two magnetic parts 22 is greater than the elasticity of elastic component 18, the number of teeth of rack 19 is greater than gear 21's the number of teeth of a wheel, through the setting that leads to the groove, make reciprocating of striking piece 24 can not influence moving down of rack 19 and move, thereby avoid both to influence each other, lead to the unable above-mentioned function of realizing of this device.

The use method (working principle) of the invention is as follows:

in operation, the placing plate is placed on the mounting table, the lifting mechanism 3 (in the prior art) drives the mold 2 to move downwards to make the bottom surface of the mold 2 closely fit with the upper surface of the placing plate, then the mixed material is poured into the cavity of the mold 2 (due to a certain adhesion force between the mixed material, the mixed material is not discharged from the remainder hole actively), then the pressing member 4 (in the prior art) drives the molding member 5 to extend downwards into the material, so that the material right below the rod body of the molding member 5 is pushed out from the remainder hole by the molding member 5, while the material at the rest position is extruded, a small amount of material enters the inclined surface of the discharging member 14, during the process, the first magnetic member 6 inside the molding member 5 gradually approaches and attracts the second magnetic member 22, then the second magnetic member 22 drives the rack 19 to move downwards as the molding member 5 continues to move downwards, the elastic member 18 is stretched, the downward rack 19 drives the gear 21 to rotate, so that the rotating cylinder 20 rotates therewith, the rotating cylinder 20 drives the impacting member 24 to drive the rack 19 to move downwards through the impacting member 24, when the rotating cylinder 20 to move upwards and downwards, the rack 17 moves back to the upper and the lifting member 14, the elastic member 14 moves, and the lifting member 17 moves back to the lifting member 14, and the lifting member 14, when the elastic member 17 moves upwards and the elastic member 14 moves back to move upwards and the lifting member 17, the middle position of the rough blank in the die 2 is hollow, then the lifting mechanism 3 drives the die 2 to move upwards, so that the unloading part 14 extends into the die 2 along with the rough blank and pushes the rough blank to move downwards, in the process, the driving magnet 9 in the die 2 attracts the driven magnet 11, the driven piston 10 moves upwards and extrudes the liquid medium in the liquid cavity 8, the medium enters the lifting cavity 15 through the liquid guide hole 12 and pushes the first lifting plate 16, the elastic part 18 and the second lifting plate 17 to move downwards, the rack 19 and the gear 21 form meshing transmission again, the rotating cylinder 20 drives the impact part 24 to impact the unloading part 14 in a reciprocating mode through the connecting plate 23, the unloading part 14 generates vibration, the rough blank in the die 2 is smoothly separated from the die 2 through the action, then when the die 2 moves upwards to the limit position, a worker takes down the placing plate and places a new placing plate, then the lifting mechanism 3 drives the die 2 to move downwards, and the reset structure is a work cycle.

It should be noted that, in this document, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides a hollow brick press forming device, includes mount (1), the inside bottom surface fixed mounting of mount (1) has mount table and lifting mechanism (3), the up end of mount table is placed inside and is run through the board of placing of seting up the clout hole, the last surface mounting of placing the board has mould (2), the output rod of lifting mechanism (3) forms fixed connection with the bottom surface that mould (2) edge stretched out the end, the last side fixed mounting of mount (1) has output rod to stretch into mount (1) inside lower pressure member (4), the tip fixed mounting of lower pressure member (4) output rod has formed part (5), its characterized in that: the last fixed surface of lifting mechanism (3) cylinder body installs dead lever (7), dead lever (7) divide into vertical pole and transverse bar, the lower extreme of vertical pole forms fixed connection with the upper surface of lifting mechanism (3) cylinder body, the upper end department fixed mounting of vertical pole has the transverse bar, transverse bar face has fixed plate (13) to the one end fixed mounting of formed part (5), the lower extreme fixed mounting of fixed plate (13) has unloading piece (14), the lateral wall body of unloading piece (14) forms sliding connection with the inner wall of mould (2).

2. A hollow brick press-forming apparatus as claimed in claim 1, wherein: the upper side surface of the unloading piece (14) is arranged in an inclined surface structure.

3. A hollow brick press-forming apparatus as claimed in claim 2, wherein: vertical pole inside has seted up sap cavity (8), the inside position fixed mounting who is close to sap cavity (8) of mould (2) has driving magnet (9), sealed movable mounting has driven piston (10) that are in same horizontality with driving magnet (9) in sap cavity (8), driven piston (10) inside fixed mounting has driven magnet (11) that are heteropolar looks and inhale with driving magnet (9), be filled with liquid medium in the cavity that lies in driven piston (10) top position in sap cavity (8), drain hole (12) have been seted up jointly to horizontal pole and fixed plate (13) inside.

4. A hollow brick press-forming apparatus as claimed in claim 3, wherein: lifting cavity (15) have been seted up to the inside of fixed plate (13), sealed movable mounting has lifter plate (16) No. one in the inner chamber of lifting cavity (15), drain hole (12) are used for communicating cavity and lifting cavity (15) in cavity that lie in slave piston (10) top position in liquid chamber (8) and lie in the cavity of lifter plate (16) top position, lifter plate (17) No. two are installed to the below position of lifter plate (16), lifter plate (17) and lifting cavity (15) form sealed swing joint No. two, one side position fixed mounting of lifter plate (17) lower surface has rack (19), install in the cavity that lies in lifter plate (17) below position No. two (20) and rotate a section of thick bamboo (20), the leading flank fixed mounting that rotates a section of thick bamboo (20) has gear (21) of being connected with rack (19) formation meshing, the leading flank fixed mounting of gear (21) has the pivot, the opposite side of pivot forms the rotation with the leading side inner wall of lifting cavity (15) and is connected.

5. A hollow brick press-forming device according to claim 4, characterized in that: the eccentric articulated company's of side face behind a rotation section of thick bamboo (20) has even board (23), slidable mounting has striking piece (24) that the downside contacted unloads material (14) in the cavity that lies in a rotation section of thick bamboo (20) below position in lift chamber (15), the last side of striking piece (24) forms articulated fixed with the lower terminal surface that links board (23).

6. A hollow brick press-forming device according to claim 5, characterized in that: the inside fixed mounting of plate body of formed part (5) has magnetic part (6) No. one, the inside of No. two lifter plates (17) is run through and has been seted up the through-hole, the inside fixed mounting of No. two lifter plates (17) has magnetic part (22) No. two that are heteropolar looks attracting with magnetic part (6).

7. A hollow brick press-forming device according to claim 6, characterized in that: an elastic part (18) is fixedly arranged between the upper surface of the second lifting plate (17) and the lower surface of the first lifting plate (16) together and used for driving the second lifting plate (17) to reset.

8. A hollow brick press-forming device according to claim 7, characterized in that: the inside of striking piece (24) is seted up and is perpendicular logical groove that corresponds with rack (19), the cross-sectional area that leads to the groove is greater than the cross-sectional area of rack (19), magnetic attraction between initiative magnet (9) and driven magnet (11) is greater than the magnetic attraction between magnetic part (6) and No. two magnetic parts (22), magnetic attraction between magnetic part (6) and No. two magnetic parts (22) is greater than the elasticity of elastic component (18), the number of teeth of rack (19) is greater than the number of teeth of gear (21).