CN111942324B

CN111942324B - Internal connection type GPS/Beidou positioning anti-theft device

Info

Publication number: CN111942324B
Application number: CN202010691627.1A
Authority: CN
Inventors: 熊用; 张慕华; 刘辅; 雷孟飞; 吴通海
Original assignee: Hunan Lianzhi Technology Co Ltd
Current assignee: Hunan Lianzhi Technology Co Ltd
Priority date: 2020-07-17
Filing date: 2020-07-17
Publication date: 2021-08-03
Anticipated expiration: 2040-07-17
Also published as: CN111942324A

Abstract

The invention discloses an internal connection type GPS/Beidou positioning anti-theft device, which belongs to the technical field of vehicle-mounted equipment and comprises a shell and a wireless remote controller, wherein a mounting port is formed in the middle of the top end of the shell, a protective cover plate is arranged on the mounting port, a motor used for driving the protective cover plate to slide is arranged in the shell, the wireless remote controller is connected with the motor and used for controlling the motor to rotate forwards and backwards, a GPS anti-theft device is arranged in the shell, the protective cover plate comprises a first sliding cover plate and a first sliding chute, the first sliding chute is arranged in the shell and used for sliding the first sliding cover plate, the first sliding chute is arranged at the front end of the top of the shell, a sliding cavity used for containing the first sliding cover plate is formed in the rear end of the top of the shell, and a threaded driving rod extending towards the inside of the sliding cavity horizontally is arranged on the right side of the inside of the first sliding chute. The GPS burglar alarm is protected doubly through the mutual matching of the first sliding cover plate and the second sliding cover plate, so that the safety performance of the GPS burglar alarm is improved.

Description

Internal connection type GPS/Beidou positioning anti-theft device

Technical Field

The invention relates to the technical field of capacitive touch screen protection, in particular to an internal GPS/Beidou positioning anti-theft device.

Background

The automobile burglar alarm is a high-tech anti-theft product integrating a GSM network digital mobile communication technology and a GPS satellite positioning technology, at present, an automobile becomes an important vehicle for people to go out, and the value of the automobile is higher, so that the automobile burglar alarm also becomes the target of a plurality of thieves; in order to prevent the automobile from being stolen, a GPS or Beidou burglar alarm is generally arranged in the automobile.

The existing anti-theft devices for most automobiles are easy to remove due to the fact that the anti-theft devices mounted in automobiles cannot be protected doubly, and automatic alarm occurs when a cover plate on the anti-theft devices (namely, mounting doors on the anti-theft devices) cannot be opened under the control of a non-wireless remote controller, so that lawless persons can take advantage of the anti-theft devices, and therefore an internal GPS/Beidou positioning anti-theft device is urgently needed to be developed.

Disclosure of Invention

1. Technical problem to be solved

The invention aims to provide an internal GPS/Beidou positioning anti-theft device to solve the problems in the background technology.

2. Technical scheme

In order to solve the problems, the invention adopts the following technical scheme:

an internal connection type GPS/Beidou positioning anti-theft device comprises a shell and a wireless remote controller, wherein a mounting opening is formed in the middle of the top end of the shell, a protective cover plate is arranged on the mounting opening, a motor used for driving the protective cover plate to slide is mounted inside the shell, the wireless remote controller is connected with the motor and used for controlling the motor to rotate positively and negatively, a GPS anti-theft device is mounted inside the shell, the protective cover plate comprises a first sliding cover plate and a first sliding chute, the first sliding chute is arranged inside the shell and used for sliding the first sliding cover plate, the first sliding chute is arranged at the front end of the top of the shell, a sliding cavity used for containing the first sliding cover plate is formed in the rear end of the top of the shell, a threaded driving rod extending towards the inside of the sliding cavity is arranged on the right side of the inside of the first sliding chute, the other end of the threaded driving rod is rotatably connected with the inner wall of the sliding cavity, a limiting sliding rod extending towards the inside of the sliding cavity is arranged on the left side of the inside of the first sliding chute, the limiting slide bar and the thread driving rod respectively penetrate through the left end and the right end of the first sliding cover plate, a through hole for the limiting slide bar and the thread driving rod to pass through is formed in the first sliding cover plate, a thread ring matched with the thread structure on the thread driving rod is arranged in the through hole for the thread driving rod to pass through on the first sliding cover plate, a second sliding cover plate with an L-shaped side surface is arranged in the sliding cavity, the vertical part of the second sliding cover plate is in sliding connection with the sliding cavity, the horizontal part of the second sliding cover plate extends towards the front end of the shell, a second sliding chute for the second sliding cover plate to slide is formed in the front end of the top of the shell, the horizontal part of the second sliding cover plate is positioned above the first sliding cover plate and is parallel to the first sliding cover plate, and the vertical parts of the first sliding cover plate and the second sliding cover plate are arranged in an aligned mode, the inside mounting of second spout has contact switch, and contact switch is connected with the siren in the car, second sliding cover is equipped with the contact that aligns the setting with contact switch towards the one end of second spout, be equipped with the extending structure that the number is at least one between second sliding cover and the vertical position of first sliding cover.

Preferably, the inner bottom of the shell is fixedly provided with a supporting frame in a rectangular frame structure, the GPS burglar alarm is fixedly connected with the supporting frame through bolts, and the supporting frame is arranged in a hollow mode.

Preferably, the inside left and right sides symmetry of casing is equipped with the limit structure who is used for fixed GPS alarm, limit structure includes L type fixed plate of overlap joint in GPS alarm top surface and the screw rod with the vertical position perpendicular fixed connection of L type fixed plate, every the outside terminal surface of L type fixed plate horizontal position all overlaps in GPS alarm's top surface, and the medial surface of every L type fixed plate vertical position all contacts with the lateral wall that the GPS alarm corresponds, every equal thread bush is equipped with threaded sleeve on the free end of screw rod, the inside left and right sides of casing all sets up a notch that is used for holding corresponding side threaded sleeve tip, every all glue on the terminal surface that L type fixed plate and GPS alarm contacted and have the rubber pad, two the terminal surface of L type fixed plate horizontal position passes through bolt fixed connection.

Preferably, extending structure locates the telescopic link that the sleeve is inside and be the cylinder structure and locates the spring inside the sleeve, every including fixed sleeve, the slip of locating first slip apron tip the sleeve all is connected, every through fixed plate and first slip apron the both ends of spring respectively with fixed plate, the telescopic link fixed connection that correspond, every the free end of telescopic link all extends to the inside of second slip apron, and the inside of second slip apron seted up with the slide of telescopic link one-to-one and alignment to every telescopic link is located the inside one end of slide and all is equipped with the saddle with corresponding slide sliding connection.

Preferably, each telescopic link is located the one end that corresponds inside the sleeve and all is equipped with the number and is two at least and be the spacing slider of fan ring column structure, every telescopic inside all is seted up and is supplied to correspond the gliding spacing spout of spacing slider, the diameter of spacing slider is greater than the diameter of the through-hole that supplies the telescopic link to pass on the sleeve.

3. Advantageous effects

1. The second sliding cover plate is connected with the first sliding cover plate through a telescopic structure, so that the second sliding cover plate can move in a single direction under the pushing of external force, when a contact on the second sliding cover plate is in contact with a contact switch in a second sliding groove under the driving of the external force, an alarm in a vehicle can generate alarm prompt to warn a vehicle thief, meanwhile, the attention of people to the vehicle can be improved through the alarm sound, a lawless person can not take advantage of the vehicle, in addition, the first sliding cover plate can be opened or closed only under the driving of a motor, and the motor can be closed or opened only by a wireless remote controller when being started, the first sliding cover plate can be opened or closed only under the control of the wireless remote controller through the arrangement of the driving mode of the first sliding cover plate, so that the dismounting difficulty of the first sliding cover plate is increased, the GPS burglar alarm is doubly protected through the mutual matching of the first sliding cover plate and the second sliding cover plate, so as to improve the safety performance of the GPS burglar alarm.

2. The invention can limit the GPS burglar alarm when in use by the L-shaped fixing plates through the screw connection between the two L-shaped fixing plates and the clamping connection between the threaded sleeve and the notch, so as to reduce the influence on the stability of the GPS burglar alarm caused by shaking when a vehicle runs, thereby achieving the protection effect, and can improve the attaching effect of the L-shaped fixing plates and the GPS burglar alarm through the rubber pads adhered on the L-shaped fixing plates, thereby improving the limiting effect of the L-shaped fixing plates on the GPS burglar alarm.

3. The telescopic rod of the invention forms an elastic telescopic structure between the spring and the sleeve, namely, the contact on the second sliding cover plate can not be contacted with the contact switch when the automobile is in a normal state through the elasticity of the spring, so as to ensure that the automobile cannot generate an alarm in a safe state, avoid the influence of the false alarm of an anti-theft device on the rest and daily life of nearby residents, and in addition, through the sliding of the limiting slide block and the limiting slide groove, the derailment of the telescopic rod can be avoided when the telescopic rod is extended, so that the second sliding cover plate can only move to one side of the shell under the pushing of external force, and the use effect of the telescopic structure is ensured.

4. The support frame is provided with the hollow structure, so that the GPS burglar alarm can be cooled during working, the influence of more heat on the normal working of the GPS burglar alarm is reduced, and the protection effect is achieved.

Drawings

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

FIG. 2 is a side view of the internal structure of the present invention;

FIG. 3 is a schematic structural view of the connection between the first sliding cover and the second sliding cover;

FIG. 4 is a schematic view of the connection of the sliding cover plate with the threaded drive rod;

fig. 5 is an enlarged schematic view of a portion a in fig. 3.

Reference numerals: 1-shell, 2-mounting opening, 3-GPS burglar alarm, 4-supporting frame, 5-L type fixing plate, 6-screw rod, 7-threaded sleeve, 8-notch, 9-rubber pad, 10-bolt, 11-first sliding cover plate, 12-first sliding groove, 13-motor, 14-threaded driving rod, 15-second sliding cover plate, 16-sliding cavity, 17-wireless remote controller, 18-limiting sliding rod, 19-second sliding groove, 20-contact switch, 21-contact, 22-sleeve, 23-telescopic rod, 24-fixing plate, 25-spring, 26-saddle, 27-slideway, 28-limiting sliding block and 29-limiting sliding groove.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Examples

An internal connection type GPS/Beidou positioning anti-theft device shown in figures 1-5 comprises a shell 1 and a wireless remote controller 17, wherein a mounting port 2 is arranged in the middle of the top end of the shell 1, a protective cover plate is arranged on the mounting port 2, a motor 13 for driving the protective cover plate to slide is arranged inside the shell 1, the wireless remote controller 17 is connected with the motor 13 and used for controlling the motor 13 to rotate forwards and backwards, a GPS anti-theft device 3 is arranged inside the shell 1, a supporting frame 4 in a rectangular frame structure is fixedly arranged at the inner bottom of the shell 1, the GPS anti-theft device 3 is fixedly connected with the supporting frame 4 through a bolt 10, the supporting frame 4 is arranged in a hollow manner, and the hollow structure of the supporting frame 4 is arranged, so that the GPS anti-theft device 3 can dissipate heat during working, the influence of more heat on the normal working of the GPS anti-theft device 3 is reduced, and the protective effect is achieved;

the left side and the right side inside the shell 1 are symmetrically provided with a limiting structure for fixing the GPS burglar alarm 3, the limiting structure comprises L-shaped fixing plates 5 which are lapped on the top end surface of the GPS burglar alarm 3 and screw rods 6 which are vertically and fixedly connected with the vertical parts of the L-shaped fixing plates 5, the outer end face of the horizontal part of each L-shaped fixing plate 5 is lapped on the top end surface of the GPS burglar alarm 3, the inner end face of the vertical part of each L-shaped fixing plate 5 is contacted with the corresponding side wall of the GPS burglar alarm 3, the free end of each screw rod 6 is sleeved with a threaded sleeve 7 in a threaded manner, the left side and the right side inside the shell 1 are respectively provided with a notch 8 for containing the end part of the corresponding threaded sleeve 7, the end face of each L-shaped fixing plate 5 contacted with the GPS burglar alarm 3 is adhered with a rubber pad 9, the end faces of the horizontal parts of the two L-shaped fixing plates 5 are fixedly connected through bolts 10, and the fixed connection between the L-shaped fixing plates 5 and the threaded sleeves 7 and the notches 8, the L-shaped fixing plate 5 can limit the GPS burglar alarm 3 in use, so that the influence of shaking on the stability of the GPS burglar alarm 3 when a vehicle runs is reduced, the protection effect is achieved, in addition, the attaching effect of the L-shaped fixing plate 5 and the GPS burglar alarm 3 can be improved through the rubber pad 9 adhered to the L-shaped fixing plate 5, the limiting effect of the L-shaped fixing plate 5 on the GPS burglar alarm 3 is improved, and the installation of the GPS burglar alarm 3 by people can be facilitated through the threaded connection between the threaded sleeve 7 and the screw rod 6 and the screw connection between the two L-shaped fixing plates 5, so that convenience is provided for later-stage maintenance and replacement of the GPS burglar alarm 3, and meanwhile, the flexibility of the use of the burglar alarm is improved;

the protective cover plate comprises a first sliding cover plate 11 arranged horizontally and a first sliding chute 12 arranged inside the shell 1 and used for sliding the first sliding cover plate 11, the first sliding chute 12 is arranged at the front end of the top of the shell 1, a sliding cavity 16 used for containing the first sliding cover plate 11 is arranged at the rear end of the top of the shell 1, a threaded driving rod 14 extending horizontally towards the inside of the sliding cavity 16 is arranged on the right side of the inside of the first sliding chute 12, the other end of the threaded driving rod 14 is rotatably connected with the inner wall of the sliding cavity 16, a limiting sliding rod 18 extending horizontally towards the inside of the sliding cavity 16 is arranged on the left side of the inside of the first sliding chute 12, the limiting sliding rod 18 is fixedly connected with the inner wall of the sliding cavity 16, the limiting sliding rod 18 and the threaded driving rod 14 penetrate through the left end and the right end of the first sliding cover plate 11 respectively, a through hole for the limiting sliding rod 18 and the threaded driving rod 14 to penetrate is formed in the inside of the through hole for the threaded driving rod 14 to be matched with a threaded structure on the threaded driving rod 14 A second sliding cover plate 15 with an L-shaped side surface is arranged in the sliding cavity 16 of the closed thread ring, the vertical part of the second sliding cover plate 15 is connected with the sliding cavity 16 in a sliding way, the horizontal part of the second sliding cover plate 15 extends to the front end of the shell 1, the front end of the top of the shell 1 is provided with a second sliding chute 19 for the second sliding cover plate 15 to slide, the horizontal part of the second sliding cover plate 15 is positioned above the first sliding cover plate 11 and is parallel to the first sliding cover plate 11, the vertical parts of the first sliding cover plate 11 and the second sliding cover plate 15 are arranged in an alignment way, a contact switch 20 is arranged in the second sliding chute 19, a contact switch 20 is connected with an alarm in the vehicle, one end of the second sliding cover plate 15 facing the second sliding chute 19 is provided with a contact 21 aligned with the contact switch 20, and at least one telescopic structure is arranged between the second sliding cover plate 15 and the vertical part of the first sliding cover plate 11;

the telescopic structure comprises a sleeve 22 fixedly arranged at the end part of the first sliding cover plate 11, a telescopic rod 23 which is arranged inside the sleeve 22 in a sliding manner and is of a cylindrical structure, and springs 25 arranged inside the sleeve 22, wherein each sleeve 22 is connected with the first sliding cover plate 11 through a fixing plate 24, two ends of each spring 25 are respectively fixedly connected with the corresponding fixing plate 24 and the telescopic rod 23, the free end of each telescopic rod 23 extends into the second sliding cover plate 15, slide ways 27 which are in one-to-one correspondence with and aligned with the telescopic rods 23 are arranged inside the second sliding cover plate 15, one end of each telescopic rod 23, which is positioned inside the slide way 27, is provided with a supporting platform 26 which is in sliding connection with the corresponding slide way 27, the telescopic rod 23 forms an elastic telescopic structure through the springs 25 and the sleeve 22, namely, the contact 21 on the second sliding cover plate 15 can not be contacted with the contact switch 20 through the elastic force of the springs 25, in order to guarantee that the car can not take place the police dispatch newspaper under the safe state, avoid the influence that the anti-theft device misreport led to the fact near resident's rest and daily life, every telescopic link 23 is located the inside one end of corresponding sleeve 22 and all is equipped with the number and is two at least and be the spacing slider 28 of fan loop column structure, every sleeve 22's inside is all seted up and is supplied to correspond the gliding spacing spout 29 of spacing slider 28, spacing slider 28's diameter is greater than the diameter of the through-hole that supplies telescopic link 23 to pass on the sleeve 22, slip through spacing slider 28 and spacing spout 29, can avoid telescopic link 23 derail to appear when the extension, with this make second sliding cover plate 15 can only remove to one side of casing 1 under the promotion of external force, telescopic structure's result of use has been guaranteed.

The internal connection type GPS/Beidou positioning anti-theft device has the specific application process that: when the automobile anti-theft device is used, the limiting slide block 28 on the telescopic rod 23 is positioned at the end part of the sleeve 22 when the spring 25 is in a natural state, so that the telescopic rod 23 can only contract in the sleeve 22 under the action of external force, the second sliding cover plate 15 moves towards the end part of the second sliding groove 19 when the telescopic rod 23 contracts into the sleeve 22, when the contact 21 on the second sliding cover plate 15 is driven by external force to be in contact with the contact switch 20 in the second sliding groove 19, an alarm in the automobile can give an alarm prompt to warn a vehicle-thief, meanwhile, the attention of people to the automobile can be improved through the alarm sound, so that lawless persons can take advantage of the alarm, in addition, the first sliding cover plate 11 can be opened or closed only under the driving of the motor 13, and the motor 13 can be closed or opened only by the wireless remote controller 17 when being started, and the arrangement of the driving mode of the first sliding cover plate 11 is adopted, the first sliding cover plate 11 can be opened or closed only under the control of the wireless remote controller 17, so that the difficulty of dismantling the first sliding cover plate 11 by lawless persons is increased, and the GPS burglar alarm 3 can be protected doubly through the mutual matching of the first sliding cover plate 11 and the second sliding cover plate 15, so as to improve the safety performance of the GPS burglar alarm 3, in addition, the telescopic rod 23 forms an elastic telescopic structure through the spring 25 and the sleeve 22, namely, the contact 21 on the second sliding cover plate 15 can not be contacted with the contact switch 20 when the automobile is in a normal state through the elastic force of the spring 25, so that the automobile can not generate an alarm in a safe state, and the influence of the mistaken reporting of an anti-theft device on the rest and daily life of nearby residents is avoided;

when a vehicle runs, the L-shaped fixing plate 5 can limit the GPS burglar alarm 3 in use through the screw connection between the two L-shaped fixing plates 5 and the clamping connection between the threaded sleeve 7 and the notch 8, so as to reduce the influence of shaking on the stability of the GPS burglar alarm 3 when the vehicle runs, and further achieve the protection effect, in addition, the bonding effect of the L-shaped fixing plate 5 and the GPS burglar alarm 3 can be improved through the rubber pad 9 bonded on the L-shaped fixing plate 5, so as to improve the limiting effect of the L-shaped fixing plate 5 on the GPS burglar alarm 3, the GPS burglar alarm 3 can be conveniently installed by people through the threaded connection between the threaded sleeve 7 and the screw rod 6 and the screw connection between the two L-shaped fixing plates 5, so that convenience is provided for later overhaul and replacement of the GPS burglar alarm 3, the GPS burglar alarm 3 can pass through the hollow structure of the supporting frame 4 when in work, the GPS burglar alarm 3 is cooled during working so as to reduce the influence of more heat on the normal work of the GPS burglar alarm 3 and achieve the protection effect, thus completing the use process of the internally-connected GPS/Beidou positioning antitheft device.

It should be understood by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as a limitation of the present invention, and that the changes and modifications of the above embodiments are within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.

Claims

1. An internal GPS positioning anti-theft device comprises a shell (1) and a wireless remote controller (17), wherein a mounting port (2) is arranged in the middle of the top end of the shell (1), a protective cover plate is arranged on the mounting port (2), the internal mounting of the shell (1) is used for driving a motor (13) with the protective cover plate sliding, the wireless remote controller (17) is connected with the motor (13) and used for controlling the motor (13) to rotate forwards and backwards, a GPS burglar alarm (3) is arranged in the shell (1), the internal GPS positioning anti-theft device is characterized in that the protective cover plate comprises a first sliding cover plate (11) which is horizontally arranged and a first sliding chute (12) which is arranged in the shell (1) and used for sliding the first sliding cover plate (11), the first sliding chute (12) is arranged at the front end of the top of the shell (1), a sliding cavity (16) used for containing the first sliding cover plate (11) is arranged at the rear end of the top of the shell (1), a threaded driving rod (14) horizontally extending into the sliding cavity (16) is arranged on the right side inside the first sliding chute (12), the other end of the threaded driving rod (14) is rotatably connected with the inner wall of the sliding cavity (16), a limiting slide rod (18) horizontally extending into the sliding cavity (16) is arranged on the left side inside the first sliding chute (12), the limiting slide rod (18) is fixedly connected with the inner wall of the sliding cavity (16), the limiting slide rod (18) and the threaded driving rod (14) respectively penetrate through the left end and the right end of the first sliding cover plate (11), a through hole for the limiting slide rod (18) and the threaded driving rod (14) to penetrate through is formed in the first sliding cover plate (11), a threaded ring matched with the threaded structure on the threaded driving rod (14) is arranged inside the through hole for the threaded driving rod (14) to penetrate through, a second sliding cover plate (15) with an L-shaped side structure is arranged inside the sliding cavity (16), vertical position and sliding cavity (16) sliding connection of second sliding cover board (15), and the horizontal position of second sliding cover board (15) extends to the front end of casing (1), casing (1) top front end is seted up and is supplied gliding second spout (19) of second sliding cover board (15), the horizontal position of second sliding cover board (15) is located the top of first sliding cover board (11) and is parallel with first sliding cover board (11), first sliding cover board (11) aligns the setting with the vertical position of second sliding cover board (15), the internally mounted of second spout (19) has contact switch (20), and contact switch (20) are connected with the siren in the car, second sliding cover board (15) are equipped with contact (21) that align the setting with contact switch (20) towards the one end of second spout (19), be equipped with the flexible position that the number is one at least between vertical position of second sliding cover board (15) and first sliding cover board (11), the flexible position that is equipped with the number Structure;

the extending structure is including fixed sleeve (22), the slip of locating first slip apron (11) tip locate inside telescopic link (23) that just is the cylinder structure of sleeve (22) and locate inside spring (25) of sleeve (22), every sleeve (22) all are connected with first slip apron (11) through fixed plate (24), every the both ends of spring (25) respectively with corresponding fixed plate (24), telescopic link (23) fixed connection, every the free end of telescopic link (23) all extends to the inside of second slip apron (15), and the inside of second slip apron (15) seted up slide (27) with telescopic link (23) one-to-one and align to the one end that every telescopic link (23) are located slide (27) inside all is equipped with and corresponds slide (27) sliding connection's saddle (26).

2. An internal connection type GPS positioning anti-theft device according to claim 1, characterized in that a supporting frame (4) with a rectangular frame structure is fixedly arranged at the inner bottom of the housing (1), the GPS anti-theft device (3) is fixedly connected with the supporting frame (4) through a bolt (10), and the supporting frame (4) is hollow.

3. The internal GPS positioning anti-theft device according to claim 1, wherein the left and right sides inside the casing (1) are symmetrically provided with a limiting structure for fixing the GPS anti-theft device (3), the limiting structure comprises an L-shaped fixing plate (5) overlapping the top end surface of the GPS anti-theft device (3) and a screw (6) vertically and fixedly connected with the vertical part of the L-shaped fixing plate (5), the outer end surface of the horizontal part of each L-shaped fixing plate (5) is overlapped on the top end surface of the GPS anti-theft device (3), the inner end surface of the vertical part of each L-shaped fixing plate (5) is contacted with the corresponding side wall of the GPS anti-theft device (3), the free end of each screw (6) is threaded and sleeved with a threaded sleeve (7), the left and right sides inside the casing (1) are provided with a notch (8) for accommodating the end part of the threaded sleeve (7) on the corresponding side, each L-shaped fixing plate (5) is adhered with a rubber pad (9) on the end face contacted with the GPS burglar alarm (3), and the end faces of the horizontal parts of the two L-shaped fixing plates (5) are fixedly connected through bolts (10).

4. The internal GPS positioning anti-theft device according to claim 1, wherein at least two limiting sliding blocks (28) in a fan-ring structure are arranged at one end of each telescopic rod (23) located inside the corresponding sleeve (22), a limiting sliding groove (29) for the corresponding limiting sliding block (28) to slide is formed inside each sleeve (22), and the diameter of each limiting sliding block (28) is larger than that of a through hole in each sleeve (22) through which the telescopic rod (23) passes.