CN213880458U

CN213880458U - Handheld intelligent terminal based on Beidou satellite communication

Info

Publication number: CN213880458U
Application number: CN202022206557.4U
Authority: CN
Inventors: 吴有龙; 杨忠; 殷婷婷; 徐楠; 杨荣根
Original assignee: Jinling Institute of Technology
Current assignee: Jinling Institute of Technology
Priority date: 2020-09-30
Filing date: 2020-09-30
Publication date: 2021-08-03
Anticipated expiration: 2030-09-30

Abstract

The utility model discloses a handheld intelligent terminal based on Beidou satellite communication, which comprises a first shell, a second shell and a terminal shell, wherein the first shell and the second shell are both C-shaped, the first shell and the second shell are symmetrically arranged, the upper half part of the terminal shell is connected between two vertical edges of the second shell in a sliding way, the lower half part of the terminal shell is connected between two vertical edges of the first shell in a sliding way, one side of the first shell and one side of the second shell are respectively welded with a first back plate and a second back plate vertically, and the first back plate and the second back plate are both internally provided with power supply mechanisms for supplying power to the terminal, the tops of two vertical edges of the first shell are both provided with first fixing mechanisms for fixing the second shell, and two perpendicular limit bottoms of second shell all are equipped with the second fixed establishment that is used for fixed first shell, first notch has vertically been seted up on the horizontal limit of first shell. The utility model discloses the dust influences the inside components and parts in terminal, and then has improved the life at this terminal.

Description

Handheld intelligent terminal based on Beidou satellite communication

Technical Field

The utility model relates to a big dipper satellite communication technical field especially relates to a handheld intelligent terminal based on big dipper satellite communication.

Background

The Beidou satellite navigation system consists of a space section, a ground section and a user section, can provide high-precision, high-reliability positioning, navigation and time service for various users all day long in the global range, has short message communication capacity, and needs to use a handheld intelligent terminal during Beidou satellite communication.

The handheld intelligent terminal of current big dipper satellite communication does not have the dustproof function to the mouth that charges, leads to in the dust can get into the terminal when using, influences the inside components and parts at terminal, reduces the life at terminal.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the shortcoming that exists among the prior art, and the handheld intelligent terminal based on big dipper satellite communication who proposes.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a handheld intelligent terminal based on Beidou satellite communication comprises a first shell, a second shell and a terminal shell, wherein the first shell and the second shell are C-shaped and are symmetrically arranged, the upper half part of the terminal shell is slidably connected between two vertical edges of the second shell, the lower half part of the terminal shell is slidably connected between two vertical edges of the first shell, a first back plate and a second back plate are respectively and vertically welded on one side of the first shell and one side of the second shell, power supply mechanisms for supplying power to a terminal are respectively arranged in the first back plate and the second back plate, a first fixing mechanism for fixing the second shell is respectively arranged at the tops of the two vertical edges of the first shell, a second fixing mechanism for fixing the first shell is respectively arranged at the bottoms of the two vertical edges of the second shell, a first notch is vertically formed in the transverse edge of the first shell, and a second notch is vertically formed in the bottom of the terminal shell, first notch and second notch position looks adaptation, and the equal vertical welding in both ends of bottom symmetry has a fixed plate, two in the terminal shell the equal horizontal welding in opposite side center department of fixed plate has the third spring, and the equal horizontal welding in opposite side top of two fixed plates has the dead lever, bottom center department is equipped with and is used for preventing that the dust from getting into the inside dustproof mechanism of terminal shell in the terminal shell.

Preferably, the power supply mechanism comprises a first battery and a second battery, the first backboard and the second backboard are both hollow, the first battery is vertically installed inside the first backboard, the second battery is vertically installed inside the second backboard, and the first battery is electrically connected with the terminal battery.

Preferably, the first fixing mechanism comprises a second groove, the second groove is vertically formed in the center of the top of the vertical edge of the first shell, the first groove is horizontally formed in one side of the inner portion of the second groove, a second copper sheet is horizontally bonded to the top of the first groove, a second spring is vertically welded to the center of the bottom of the second groove, and the second copper sheet is electrically connected with the first battery.

Preferably, the second fixing mechanism comprises a convex plate, the convex plate is hollow, the top of the convex plate is vertically welded at the center of the bottom of the vertical edge of the second shell, the convex plate is communicated with the second shell, the convex plate is horizontally and slidably connected with a first arc-shaped block, the top of the first arc-shaped block is horizontally bonded with a first copper sheet, one side of the convex plate is provided with an opening matched with the first arc-shaped block and the first copper sheet in shape and size, the arc end of the first arc-shaped block penetrates through the opening, and a moving mechanism used for moving the first arc-shaped block is arranged inside the convex plate.

Preferably, moving mechanism includes slide and button, and the vertical sliding connection of slide is inside the flange, the slide top is passed the flange top and sliding connection is inside the second shell, and slide one side horizontal sliding connection has the gag lever post, the gag lever post has two and is located inside second shell and the flange respectively, and two gag lever posts all pass the slide, two the gag lever post welds respectively in flange and the inside symmetrical both sides of second shell vertical limit, and slide bottom one side articulates there is the connecting rod, the connecting rod other end articulates there is the slider, and connecting rod and the equal sliding connection of slider are inside the flange, slider one end welds in first arc piece one side, and the welding of slide opposite side has first spring, the first spring other end welds in the inside one side of flange.

Preferably, the button is connected to the side of keeping away from two perpendicular limits of the second shell in a sliding manner, and the round hole matched with the button in shape and size is horizontally arranged on one side of the perpendicular limit of the second shell, the button is connected to the inside of the round hole in a sliding manner, the round hole is communicated with the inside of the second shell in a communicating manner, one end of the button penetrates through the round hole and is welded to one side of the sliding plate, the convex plate is connected to the inside of the second groove in a sliding manner, the first arc-shaped block is connected to the inside of the first groove in a sliding manner, and the first copper sheet is electrically connected with the second battery.

Preferably, dustproof mechanism includes first arc, and first arc has two and symmetry setting, two the equal horizontal sliding connection of first arc is in terminal shell bottom, and the equal vertical welding in both ends that two first arc tops were kept away from has the sliding sleeve, two the dead lever level respectively passes two sliding sleeve center departments and sliding connection respectively inside two sliding sleeves.

Preferably, the dustproof mechanism comprises second arc-shaped plates, the second arc-shaped plates are symmetrically arranged, the two second arc-shaped plates are horizontally and slidably connected to the inner bottom of the terminal shell, and the two fixing rods horizontally penetrate through the top of the side face, far away from the two second arc-shaped plates, of the two second arc-shaped plates respectively and are slidably connected to the inner portions of the two second arc-shaped plates respectively.

The utility model has the advantages that:

1. the utility model discloses, when needs charge to the terminal, insert first notch and second notch to charging plug, then the plug can extrude two first arcs, two first arcs can the relative movement when two first arcs and plug butt, then the plug can get into the terminal inside and charge to the terminal, and can carry on spacingly to two first arcs through two sliding sleeves, the stability of two first arcs operation has been guaranteed, when dialling out the plug after charging, the spring action that produces through two third springs can make two first arcs remove in opposite directions, make the dust can not get into inside the terminal, avoided the dust to the inside components and parts influence in terminal, and then improved the life at this terminal.

The utility model, before using the terminal device, the upper half of the terminal is inserted between two vertical edges of the second shell, the lower half of the terminal is inserted between two vertical edges of the first shell, the first shell or the second shell is pressed to make the first arc block enter the first groove, the first shell and the second shell can be fixed, and when the first arc block enters the second groove, the first copper sheet and the second copper sheet are contacted to make the first battery and the second battery electrically connected, and because the first battery and the internal battery of the terminal are electrically connected, the first battery and the second battery can supply power to the terminal, in addition, when charging the terminal, the first battery and the second battery can be charged, which ensures that the terminal has sufficient electric quantity when using, thereby improving the use of the terminal device frequently, and the slide plate is driven to move by pressing the button, the slide plate drives the connecting rod to move, the connecting rod drives the slider and removes, and the slider drives in the first arc piece immigration flange, can dismantle first shell and second shell, has improved the dismantlement efficiency to first shell and second shell.

The utility model discloses, when needs charge to the terminal, insert first notch and second notch to charging plug, then the plug can extrude two second arcs, two second arcs can the opposite movement with during the plug butt, then the plug can get into the terminal inside and charge to the terminal, and because two dead levers pass two second arcs, then two dead levers can carry on spacingly to two second arcs, two second arc operation's stability has been guaranteed, when dialling out the plug after charging, the elastic action that produces through two third springs can make two second arcs remove in opposite directions, make inside the dust can not get into the terminal, avoided the influence of dust to the inside components and parts in terminal, and then improved the life at this terminal.

Drawings

Fig. 1 is a schematic diagram of a separation structure of a handheld intelligent terminal based on Beidou satellite communication according to the embodiment 1 of the present invention;

fig. 2 is a schematic structural diagram of a handheld intelligent terminal based on Beidou satellite communication according to the embodiment 1 of the present invention;

fig. 3 is an enlarged view of a position a of a handheld intelligent terminal based on Beidou satellite communication according to the embodiment of the present invention 1;

fig. 4 is a cross-sectional view of a first housing of a handheld intelligent terminal based on Beidou satellite communication according to the embodiment of the present invention;

fig. 5 is a cross-sectional view of a first backplane and a second backplane of a handheld intelligent terminal based on Beidou satellite communication according to the utility model discloses embodiment 1;

fig. 6 is a cross-sectional view of the bottom of a terminal housing of a handheld intelligent terminal based on Beidou satellite communication according to the embodiment of the present invention 1;

fig. 7 is according to the utility model discloses embodiment 2 a handheld intelligent terminal's based on big dipper satellite communication cross-sectional view.

In the figure: the terminal comprises a first shell 1, a second shell 2, a terminal shell 3, a first back plate 4, a second back plate 5, a first notch 6, a first arc-shaped block 7, a first copper sheet 8, a button 9, a round hole 10, a convex plate 11, a first groove 17, a second copper sheet 18, a second groove 19, a second spring 20, a first battery 21, a second battery 22, a third spring 23, a fixing plate 24, a sliding sleeve 25, a fixing rod 26, a first arc-shaped plate 27, a second notch 28 and a second arc-shaped plate 29.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.

Example 1

Referring to fig. 1-6, a handheld intelligent terminal based on Beidou satellite communication comprises a first shell 1, a second shell 2 and a terminal shell 3, wherein the first shell 1 and the second shell 2 are both of a C type, the first shell 1 and the second shell 2 are symmetrically arranged, the upper half part of the terminal shell 3 is slidably connected between two vertical edges of the second shell 2, the lower half part of the terminal shell 3 is slidably connected between two vertical edges of the first shell 1, a first back plate 4 and a second back plate 5 are respectively and vertically welded on one side of the first shell 1 and one side of the second shell 2, a power supply mechanism for supplying power to the terminal is respectively arranged inside the first back plate 4 and the second back plate 5, a first fixing mechanism for fixing the second shell 2 is respectively arranged at the top parts of two vertical edges of the first shell 1, a second fixing mechanism for fixing the first shell 1 is respectively arranged at the bottom parts of two vertical edges of the second shell 2, a first notch 6 is vertically arranged at the transverse edge of the first shell 1, and terminal shell 3 bottom is vertical has seted up second notch 28, first notch 6 and second notch 28 position looks adaptation, and the equal vertical welding in both ends of bottom symmetry has fixed plate 24 in terminal shell 3, the equal horizontal welding in two 24 opposite side centers departments of fixed plate has third spring 23, and the equal horizontal welding in two 24 opposite side tops of fixed plate has dead lever 26, the bottom center department is equipped with and is used for preventing that the dust from getting into the inside dustproof mechanism of terminal shell 3 in terminal shell 3.

In the utility model, the power supply mechanism comprises a first battery 21 and a second battery 22, the first backboard 4 and the second backboard 5 are both hollow, the first battery 21 is vertically arranged inside the first backboard 4, the second battery 22 is vertically arranged inside the second backboard 5, the first battery 21 is electrically connected with the terminal battery, the first fixing mechanism comprises a second groove 19, the second groove 19 is vertically arranged at the center of the top of the vertical edge of the first shell 1, a first groove 17 is horizontally arranged at one side inside the second groove 19, a second copper sheet 18 is horizontally bonded at the top inside the first groove 17, a second spring 20 is vertically welded at the center of the bottom inside the second groove 19, the second copper sheet 18 is electrically connected with the first battery 21, the second fixing mechanism comprises a convex plate 11, the inside of the convex plate 11 is hollow, the top of the convex plate 11 is vertically welded at the center of the bottom of the vertical edge of the second shell 2, and the inside of the convex plate 11 is communicated with the inside of the second shell 2, a first arc-shaped block 7 is horizontally and slidably connected inside the convex plate 11, a first copper sheet 8 is horizontally bonded on the top of the first arc-shaped block 7, an opening matched with the shape and size of the first arc-shaped block 7 and the first copper sheet 8 is formed in one side of the convex plate 11, the arc-shaped end of the first arc-shaped block 7 passes through the opening, a moving mechanism for moving the first arc-shaped block 7 is arranged inside the convex plate 11 and comprises a sliding plate and a button 9, the sliding plate is vertically and slidably connected inside the convex plate 11, the top of the sliding plate passes through the top of the convex plate 11 and is slidably connected inside the second shell 2, a limiting rod is horizontally and slidably connected on one side of the sliding plate, two limiting rods are respectively positioned inside the second shell 2 and the convex plate 11 and pass through the sliding plate, the two limiting rods are respectively welded on two symmetrical sides inside the convex plate 11 and the vertical edge of the second shell 2, and a connecting rod is hinged on one side of the bottom of the sliding plate, the other end of the connecting rod is hinged with a sliding block, the connecting rod and the sliding block are both connected inside the convex plate 11 in a sliding manner, one end of the sliding block is welded on one side of the first arc-shaped block 7, the other side of the sliding plate is welded with a first spring, the other end of the first spring is welded on one side inside the convex plate 11, the button 9 is connected on the far side of two vertical edges of the second shell 2 in a sliding manner, a round hole 10 matched with the shape and size of the button 9 is horizontally arranged on one side of the vertical edge of the second shell 2, the button 9 is connected inside the round hole 10 in a sliding manner, the round hole 10 is communicated with the inside of the second shell 2, one end of the button 9 passes through the round hole 10 and is welded on one side of the sliding plate, the convex plate 11 is connected inside the second groove 19 in a sliding manner, the first arc-shaped block 7 is connected inside the first groove 17 in a sliding manner, the first copper sheet 8 is electrically connected with the second battery 22, the dustproof mechanism comprises a first arc-shaped plate 27, and the first arc-shaped block 27 is arranged symmetrically, the equal horizontal sliding connection of two first arc 27 is in the bottom in terminal housing 3, and the equal vertical welding in both ends that two first arc 27 tops were kept away from has sliding sleeve 25, and two dead levers 26 level respectively pass two sliding sleeve 25 center departments and respectively sliding connection inside two sliding sleeves 25.

The working principle of the embodiment is as follows: in practical use, when the terminal needs to be charged, a charging plug is inserted into the first notch 6 and the second notch 28, the plug extrudes the two first arc-shaped plates 27, the two first arc-shaped plates 27 move oppositely when being abutted against the plug, the plug can enter the terminal to charge the terminal, the two first arc-shaped plates 27 can be limited by the two sliding sleeves 25, the running stability of the two first arc-shaped plates 27 is ensured, when the plug is pulled out after the charging is finished, the two first arc-shaped plates 27 can move oppositely through the elastic action generated by the two third springs 23, so that dust can not enter the terminal, the influence of the dust on components inside the terminal is avoided, the service life of the terminal is further prolonged, before the terminal is used, the upper half part of the terminal is inserted between the two vertical edges of the second shell 2, then the lower half part of the terminal is inserted between two vertical edges of the first shell 1, the first shell 1 or the second shell 2 is pressed to enable the first arc-shaped block 7 to enter the first groove 17, the first shell 1 and the second shell 2 can be fixed, when the first arc-shaped block 7 enters the second groove 19, the first copper sheet 8 and the second copper sheet 18 are contacted to enable the first battery 21 and the second battery 22 to be electrically connected, and because the first battery 21 and the battery inside the terminal are electrically connected, the first battery 21 and the second battery 22 can supply power to the terminal, in addition, when the terminal is charged, the first battery 21 and the second battery 22 can be charged, so that sufficient electric quantity when the terminal is used is ensured, the use of the terminal equipment is improved frequently, and the sliding plate is driven to move by pressing the button 9, the sliding plate drives the connecting rod to move, the connecting rod drives the sliding block to move, the sliding block drives the first arc-shaped block 7 to move into the convex plate 11, namely, the first housing 1 and the second housing 2 can be detached, and the efficiency of detaching the first housing 1 and the second housing 2 is improved.

Example 2

Referring to fig. 7, the present embodiment differs from embodiment 1 only in that the dust-proof mechanism includes second arc-shaped plates 29, the second arc-shaped plates 29 are symmetrically arranged, both the second arc-shaped plates 29 are horizontally and slidably connected to the bottom inside the terminal housing 3, and the two fixing rods 26 respectively horizontally penetrate through the top of the side surface away from the two second arc-shaped plates 29 and are respectively and slidably connected inside the two second arc-shaped plates 29.

The working principle of the embodiment is as follows: in the time of in-service use, when needing to charge the terminal, insert first notch 6 and second notch 28 to the charging plug, then the plug can extrude two second arc 29, two second arc 29 can move in opposite directions with during the plug butt with two second arc 29, then the plug can get into the terminal inside and charge to the terminal, and because two dead levers 26 pass two second arc 29, then two dead levers 26 can carry on spacingly to two second arc 29, two second arc 29 stability of operation have been guaranteed, when dialling out the plug after charging, the elastic action that produces through two third springs 23 can make two second arc 29 move in opposite directions, make the dust can not get into inside the terminal, avoided the dust to the inside components and parts influence of terminal, and then improved the life at this terminal.

Having shown and described the basic principles and essential features of the invention and advantages thereof, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof, and it is therefore intended that the embodiments be considered as exemplary and not limiting in any way, since the scope of the invention is defined by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein and are therefore not to be embraced therein by any reference numerals in the claims.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A handheld intelligent terminal based on Beidou satellite communication comprises a first shell (1), a second shell (2) and a terminal shell (3), and is characterized in that the first shell (1) and the second shell (2) are both of a C type, the first shell (1) and the second shell (2) are symmetrically arranged, the upper half part of the terminal shell (3) is slidably connected between two vertical edges of the second shell (2), the lower half part of the terminal shell (3) is slidably connected between two vertical edges of the first shell (1), one sides of the first shell (1) and the second shell (2) are respectively and vertically and fixedly connected with a first back plate (4) and a second back plate (5), a power supply mechanism for supplying power to the terminal is arranged inside the first back plate (4) and the second back plate (5), the top parts of the two vertical edges of the first shell (1) are respectively provided with a first fixing mechanism for fixing the second shell (2), and two perpendicular limit bottoms of second shell (2) all are equipped with the second fixed establishment that is used for fixed first shell (1), first notch (6) have been seted up to first shell (1) horizontal limit is vertical, and terminal shell (3) bottom is vertical has seted up second notch (28), first notch (6) and second notch (28) position looks adaptation, and the equal vertical fixedly connected with fixed plate (24) in both ends of bottom symmetry in terminal shell (3), two the equal horizontal fixedly connected with third spring (23) of opposite side center department of fixed plate (24), and the equal horizontal fixedly connected with dead lever (26) in opposite side top of two fixed plates (24), bottom center department is equipped with and is used for preventing that the dust from getting into the inside dustproof mechanism of terminal shell (3) in terminal shell (3).

2. The handheld intelligent terminal based on Beidou satellite communication according to claim 1, wherein the power supply mechanism comprises a first battery (21) and a second battery (22), the first backboard (4) and the second backboard (5) are both hollow, the first battery (21) is vertically installed inside the first backboard (4), the second battery (22) is vertically installed inside the second backboard (5), and the first battery (21) and the terminal battery are electrically connected.

3. The handheld intelligent terminal based on Beidou satellite communication according to claim 2, wherein the first fixing mechanism comprises a second groove (19), the second groove (19) is vertically formed in the center of the top of the vertical side of the first shell (1), a first groove (17) is horizontally formed in one side inside the second groove (19), a second copper sheet (18) is horizontally bonded to the top inside the first groove (17), a second spring (20) is vertically and fixedly connected to the center of the bottom inside the second groove (19), and the second copper sheet (18) is electrically connected with the first battery (21).

4. The handheld intelligent terminal based on Beidou satellite communication is characterized in that the second fixing mechanism comprises a convex plate (11), the interior of the convex plate (11) is hollow, the top of the convex plate (11) is vertically and fixedly connected to the center of the bottom of the vertical edge of the second shell (2), the interior of the convex plate (11) is communicated with the interior of the second shell (2), a first arc-shaped block (7) is horizontally and slidably connected to the interior of the convex plate (11), a first copper sheet (8) is horizontally bonded to the top of the first arc-shaped block (7), an opening matched with the shapes and sizes of the first arc-shaped block (7) and the first copper sheet (8) is formed in one side of the convex plate (11), the arc-shaped end of the first arc-shaped block (7) penetrates through the opening, and a moving mechanism used for moving the first arc-shaped block (7) is arranged inside the convex plate (11).

5. The hand-held intelligent terminal based on Beidou satellite communication is characterized in that the moving mechanism comprises a sliding plate and a button (9), the sliding plate is vertically and slidably connected inside the convex plate (11), the top of the sliding plate passes through the top of the convex plate (11) and is slidably connected inside the second shell (2), one side of the sliding plate is horizontally and slidably connected with a limiting rod, two limiting rods are respectively positioned inside the second shell (2) and the convex plate (11) and both the two limiting rods pass through the sliding plate, the two limiting rods are respectively and fixedly connected to the convex plate (11) and two symmetrical sides inside the vertical edge of the second shell (2), one side of the bottom of the sliding plate is hinged with a connecting rod, the other end of the connecting rod is hinged with a sliding block, the connecting rod and the sliding block are both slidably connected inside the convex plate (11), one end of the sliding block is fixedly connected to one side of the first arc-shaped block (7), and the other side of the sliding plate is fixedly connected with a first spring, and the other end of the first spring is fixedly connected with one side of the inner part of the convex plate (11).

6. The handheld intelligent terminal based on Beidou satellite communication according to claim 5, wherein the button (9) is connected to the side surface of the second shell (2) far away from two vertical edges, one side of the vertical edge of the second shell (2) is horizontally provided with a round hole (10) matched with the button (9) in shape and size, the button (9) is connected to the inside of the round hole (10) in a sliding manner, the round hole (10) is communicated with the inside of the second shell (2), one end of the button (9) penetrates through the round hole (10) and is fixedly connected to one side of the sliding plate, the convex plate (11) is connected to the inside of the second groove (19) in a sliding manner, the first arc-shaped block (7) is connected to the inside of the first groove (17) in a sliding manner, and the first copper sheet (8) is electrically connected with the second battery (22).

7. The handheld intelligent terminal based on Beidou satellite communication according to claim 6, wherein the dustproof mechanism comprises two first arc-shaped plates (27), the two first arc-shaped plates (27) are symmetrically arranged, the two first arc-shaped plates (27) are horizontally and slidably connected to the inner bottom of the terminal shell (3), sliding sleeves (25) are vertically and fixedly connected to two ends of the two first arc-shaped plates (27) far away from the tops of the two first arc-shaped plates, and the two fixing rods (26) horizontally penetrate through the centers of the two sliding sleeves (25) respectively and are slidably connected to the insides of the two sliding sleeves (25) respectively.

8. The handheld intelligent terminal based on Beidou satellite communication according to claim 6, wherein the dustproof mechanism comprises second arc-shaped plates (29), the second arc-shaped plates (29) are symmetrically arranged, the two second arc-shaped plates (29) are horizontally and slidably connected to the inner bottom of the terminal shell (3), and the two fixing rods (26) horizontally penetrate through the tops of the far sides of the two second arc-shaped plates (29) respectively and are slidably connected to the insides of the two second arc-shaped plates (29) respectively.