阅读说明：本技术 一种矿用本安型网络对讲扩音电话 (Mining ann's type network public address telephone of talkbacking ) 是由 刘晓明 于 2020-12-02 设计创作，主要内容包括：本发明涉及通讯技术领域,具体涉及一种矿用本安型网络对讲扩音电话。包括壳体,壳体内设置有扩音器、电源和电源连接器,电源连接器包括绝缘壳、静触头、动触头、静导电杆、动导电杆、波纹管以及控制装置,波纹管套装于动导电杆,且其一端与动触头相连接,另一端与绝缘壳相连接,进而与绝缘壳限定出真空腔,绝缘壳上还设置有抽气装置。本发明通过设置控制装置,在真空腔内的真空度高于或等于预设阀值时,允许动触头和静触头分离,在真空腔内的真空度低于预设阀值时,使动触头和静触头保持接触,保证安全；进一步通过设置抽气装置,能够对真空腔进行抽真空处理,在强制分离动触头和静触头时,避免起弧,便于更换零部件。(The invention relates to the technical field of communication, in particular to a mining intrinsic safety type network talkback sound amplifying telephone. The power supply connector comprises an insulating shell, a static contact, a moving contact, a static conducting rod, a moving conducting rod, a corrugated pipe and a control device, wherein the loudspeaker, a power supply and the power supply connector are arranged in the shell, the corrugated pipe is sleeved on the moving conducting rod, one end of the corrugated pipe is connected with the moving contact, the other end of the corrugated pipe is connected with the insulating shell, a vacuum cavity is further defined by the corrugated pipe and the insulating shell, and an air exhaust device is further arranged on the insulating shell. According to the invention, the control device is arranged, when the vacuum degree in the vacuum cavity is higher than or equal to a preset threshold value, the movable contact and the static contact are allowed to be separated, and when the vacuum degree in the vacuum cavity is lower than the preset threshold value, the movable contact and the static contact are kept in contact, so that the safety is ensured; further through setting up air exhaust device, can carry out evacuation processing to the vacuum cavity, when force the separation moving contact and static contact, avoid the arcing, be convenient for change spare part.)

1. The mining intrinsic safety type network talkback sound amplifying telephone is characterized in that: including the casing, be provided with megaphone, power and power connector in the casing, power connector includes:

the insulating shell is horizontally arranged in the shell, and the side wall of the insulating shell is provided with a horizontally extending sliding hole;

the conductive assembly comprises a static contact, a moving contact, a static conductive rod and a moving conductive rod; the static contact and the moving contact are correspondingly arranged in the insulating shell, the static conducting rod is fixedly arranged and the static contact is arranged at the inner end of the static conducting rod, the moving conducting rod is connected with the moving contact and is slidably arranged in the insulating shell through the sliding hole, and the static conducting rod and the moving conducting rod are respectively communicated with the loudspeaker and the power supply;

the corrugated pipe is sleeved on the movable conducting rod, one end of the corrugated pipe is connected with the movable contact, and the other end of the corrugated pipe is connected with the insulating shell so as to seal the sliding hole and further define a vacuum cavity with the insulating shell;

the control device is configured to allow the movable conducting rod to slide outwards along the insulating shell when the vacuum degree in the vacuum cavity is higher than or equal to a preset threshold value so as to separate the movable contact from the fixed contact, and block the movable conducting rod from sliding outwards when the vacuum degree in the vacuum cavity is lower than the preset threshold value so as to keep the movable contact and the fixed contact in contact.

2. The mining intrinsically safe network intercom speakerphone of claim 1, further comprising: an air channel and a communication hole are horizontally arranged on the insulating shell; the air duct is positioned above the sliding hole and is communicated with the vacuum cavity and external atmosphere, and the communication hole is vertically arranged and is communicated with the middle part of the air duct and the sliding hole; a limiting groove with an upward opening is formed in the peripheral wall of the movable conducting rod, and when the movable contact is contacted with the fixed contact, the communicating hole and the limiting groove are correspondingly arranged;

the control device comprises a first small ball, a second small ball and an elastic membrane, the elastic membrane is arranged in the air channel and swells in the vacuum cavity under the action of air pressure difference to form a pit with an outward opening, the communication hole is positioned on the outer side of the swelling of the elastic membrane, the first small ball is positioned in the pit, the second small ball is positioned in the communication hole, the first small ball and the second small ball are connected through a pull rope, and the diameter of the first small ball is larger than the aperture of the communication hole;

when the vacuum degree in the vacuum cavity is lower than a preset threshold value, the elastic membrane is reduced in deformation and pushes the first small ball outwards, so that the second small ball falls down by means of the gravity of the second small ball and drives the first small ball to fall into the top end of the communicating hole, and the second small ball falls into the limiting groove to block the movable conducting rod from moving relative to the insulating shell.

3. The mining intrinsically safe network intercom speakerphone of claim 1, further comprising: the air extracting device comprises an air extracting rotary seat and an air extracting piston, the air extracting piston is slidably mounted on the insulating shell through a first matching structure, the air extracting rotary seat is rotatably mounted at the left end of the insulating shell, and the air extracting piston is driven to move along the insulating shell through a second matching structure;

the insulating casing with it hinders the admission of external gas to correspond respectively to be provided with on the piston of bleeding first check valve and the second check valve of vacuum cavity, first check valve with the second check valve is linked together, with the swivel mount that bleeds drives the piston of bleeding to when the vacuum cavity is inside to be removed, the gas in the vacuum cavity is followed first check valve with the second check valve is discharged, and the swivel mount that bleeds drives the piston of bleeding is to keeping away from during the direction motion of vacuum cavity, the volume increase of vacuum cavity, and then improve vacuum in the vacuum cavity.

4. The mining intrinsically safe network intercom speakerphone of claim 3, further comprising: the insulating shell comprises a ceramic tube, a static end sealing cover and a dynamic end sealing cover, the ceramic tube is horizontally arranged, the static end sealing cover is arranged at the left end of the ceramic tube, and the dynamic end sealing cover is arranged at the right end of the ceramic tube; the center of the static end sealing cover is provided with an installation cavity and a shaft hole which are sequentially connected from right to left, the air exhaust piston comprises a connecting shaft section and a sealing flange which are sequentially connected from left to right, the connecting shaft section penetrates through the shaft hole, the sealing flange is positioned in the installation cavity, the air exhaust rotary seat is sleeved on the connecting shaft section, and the static conductive rod penetrates through the air exhaust piston and extends out of the air exhaust rotary seat;

the first matching structure comprises a guide groove horizontally arranged on the outer peripheral wall of the sealing flange, the inner peripheral wall surface of the mounting cavity is provided with a guide bulge, and the guide bulge is positioned in the guide groove so as to block the circumferential rotation of the air extraction piston;

the second cooperation structure includes guide block and cam groove, the guide block sets up the inner peripheral wall face of the swivel mount of bleeding, the cam groove winds the peripheral wall face of connecting shaft section sets up a week and end to end, the guide block is located in the cam groove, with it drives when the swivel mount of bleeding rotates the piston of bleeding removes.

5. The mining intrinsically safe network intercom speakerphone of claim 4, wherein: the static end sealing cover is provided with an exhaust hole which is communicated with the external atmosphere and the mounting cavity, and the first one-way valve is mounted in the exhaust hole; the sealing flange is provided with an air exhaust hole extending horizontally, and the second one-way valve is located in the air exhaust hole.

6. The mining intrinsically safe network intercom speakerphone of claim 1, further comprising: a shielding cover is further arranged in the insulating shell, is mounted on the static conducting rod and covers the static contact, the moving contact and the outer side of the corrugated pipe; the static contact is movably arranged on the static conducting rod, and an elastic insulating gasket is arranged between the static contact and the shielding cover.

7. The mining intrinsically safe network intercom speakerphone of claim 6, further comprising: and a plurality of annular flanges are arranged on the inner peripheral wall surface of the shielding cover at intervals along the horizontal direction.

8. The mining intrinsically safe network intercom speakerphone of claim 1, further comprising: and the outer peripheral walls of the static contact and the moving contact are provided with insulating outer skins.

9. The mining intrinsically safe network intercom speakerphone of claim 3, further comprising: the air extraction piston further comprises a sealing ring, and the sealing ring is arranged at the left end of the connecting shaft section.

10. The mining intrinsically safe network intercom speakerphone of claim 3, further comprising: the air exhaust rotary seat is characterized by further comprising a motor box, a motor is arranged in the motor box, a driving gear is arranged on an output shaft of the motor, transmission teeth are arranged on the outer circular surface of the air exhaust rotary seat to enable the driving gear to drive the air exhaust rotary seat to rotate, and a motor switch is arranged on the shell;

the shell is also provided with a call key, and when the call key of the other mining intrinsic safety type network talkback public address telephone connected with the shell works, the mining intrinsic safety type network talkback public address telephone enables a fixed contact and a moving contact of the mining intrinsic safety type network talkback public address telephone to be connected.

Technical Field

The invention relates to the technical field of communication, in particular to a mining intrinsic safety type network talkback sound amplifying telephone.

Background

During coal mine production, personnel on different work posts need to communicate with each other by voice at any time, and also need to broadcast the whole area to inform all personnel in the area, so the mining public address telephone is one of essential devices in coal mine fully mechanized mining work. The mining intercom has the functions of amplifying and broadcasting, allocating tasks and communicating progress or being more rapid through broadcasting notification when an emergency situation is found. When the power supply of the public address equipment is disconnected after broadcasting is finished, air between the positive contact piece and the negative contact piece can be broken down, a large amount of heat is generated, even electric arcs are generated, explosion of the public address equipment can be caused if gas leaks, and therefore the public address equipment is in a high danger.

Disclosure of Invention

According to at least one defect of the prior art, the invention provides a mine intrinsic safety type network talkback public address telephone, which aims to solve the problems of low explosion-proof level and poor safety of the existing talkback public address telephone.

The invention relates to a mining intrinsic safety type network talkback sound amplification telephone, which adopts the following technical scheme: including the casing, be provided with megaphone, power and power connector in the casing, power connector includes:

the insulating shell is horizontally arranged in the shell, and the side wall of the insulating shell is provided with a horizontally extending sliding hole;

the conductive assembly comprises a static contact, a moving contact, a static conductive rod and a moving conductive rod; the static contact and the moving contact are correspondingly arranged in the insulating shell, the static conducting rod is fixedly arranged and the static contact is arranged at the inner end of the static conducting rod, the moving conducting rod is connected with the moving contact and is slidably arranged in the insulating shell through the sliding hole, and the static conducting rod and the moving conducting rod are respectively communicated with the loudspeaker and the power supply;

the corrugated pipe is sleeved on the movable conducting rod, one end of the corrugated pipe is connected with the movable contact, and the other end of the corrugated pipe is connected with the insulating shell so as to seal the sliding hole and further define a vacuum cavity with the insulating shell;

the control device is configured to allow the movable conducting rod to slide outwards along the insulating shell when the vacuum degree in the vacuum cavity is higher than or equal to a preset threshold value so as to separate the movable contact from the fixed contact, and block the movable conducting rod from sliding outwards when the vacuum degree in the vacuum cavity is lower than the preset threshold value so as to keep the movable contact and the fixed contact in contact.

Optionally, an air duct and a communication hole are horizontally arranged on the insulating shell; the air duct is positioned above the sliding hole and is communicated with the vacuum cavity and external atmosphere, and the communication hole is vertically arranged and is communicated with the middle part of the air duct and the sliding hole; a limiting groove with an upward opening is formed in the peripheral wall of the movable conducting rod, and when the movable contact is contacted with the fixed contact, the communicating hole and the limiting groove are correspondingly arranged;

the control device comprises a first small ball, a second small ball and an elastic membrane, the elastic membrane is arranged in the air channel and swells in the vacuum cavity under the action of air pressure difference to form a pit with an outward opening, the communication hole is positioned on the outer side of the swelling of the elastic membrane, the first small ball is positioned in the pit, the second small ball is positioned in the communication hole, the first small ball and the second small ball are connected through a pull rope, and the diameter of the first small ball is larger than the aperture of the communication hole;

when the vacuum degree in the vacuum cavity is lower than a preset threshold value, the elastic membrane is reduced in deformation and pushes the first small ball outwards, so that the second small ball falls down by means of the gravity of the second small ball and drives the first small ball to fall into the top end of the communicating hole, and the second small ball falls into the limiting groove to block the movable conducting rod from moving relative to the insulating shell.

Optionally, the air extractor further comprises an air extractor, the air extractor comprises an air extracting rotary seat and an air extracting piston, the air extracting piston is slidably mounted on the insulating shell through a first matching structure, the air extracting rotary seat is rotatably mounted at the left end of the insulating shell, and the air extracting piston is driven to move along the insulating shell through a second matching structure;

the insulating casing with it hinders the admission of external gas to correspond respectively to be provided with on the piston of bleeding first check valve and the second check valve of vacuum cavity, first check valve with the second check valve is linked together, with the swivel mount that bleeds drives the piston of bleeding to when the vacuum cavity is inside to be removed, the gas in the vacuum cavity is followed first check valve with the second check valve is discharged, and the swivel mount that bleeds drives the piston of bleeding is to keeping away from during the direction motion of vacuum cavity, the volume increase of vacuum cavity, and then improve vacuum in the vacuum cavity.

Optionally, the insulating shell comprises a ceramic tube, a stationary end sealing cover and a moving end sealing cover, the ceramic tube is horizontally arranged, the stationary end sealing cover is arranged at the left end of the ceramic tube, and the moving end sealing cover is arranged at the right end of the ceramic tube; the center of the static end sealing cover is provided with an installation cavity and a shaft hole which are sequentially connected from right to left, the air exhaust piston comprises a connecting shaft section and a sealing flange which are sequentially connected from left to right, the connecting shaft section penetrates through the shaft hole, the sealing flange is positioned in the installation cavity, the air exhaust rotary seat is sleeved on the connecting shaft section, and the static conductive rod penetrates through the air exhaust piston and extends out of the air exhaust rotary seat;

the first matching structure comprises a guide groove horizontally arranged on the outer peripheral wall of the sealing flange, the inner peripheral wall surface of the mounting cavity is provided with a guide bulge, and the guide bulge is positioned in the guide groove so as to block the circumferential rotation of the air extraction piston;

the second cooperation structure includes guide block and cam groove, the guide block sets up the inner peripheral wall face of the swivel mount of bleeding, the cam groove winds the peripheral wall face of connecting shaft section sets up a week and end to end, the guide block is located in the cam groove, with it drives when the swivel mount of bleeding rotates the piston of bleeding removes.

Optionally, an exhaust hole is formed in the static end sealing cover, the exhaust hole is communicated with the external atmosphere and the installation cavity, and the first one-way valve is installed in the exhaust hole; the sealing flange is provided with an air exhaust hole extending horizontally, and the second one-way valve is located in the air exhaust hole.

Optionally, a shielding cover is further disposed in the insulating housing, and the shielding cover is mounted on the static conductive rod and covers the static contact, the moving contact and the outer side of the corrugated pipe; the static contact is movably arranged on the static conducting rod, and an elastic insulating gasket is arranged between the static contact and the shielding cover.

Optionally, a plurality of annular flanges are arranged on the inner peripheral wall surface of the shielding case at intervals along the horizontal direction.

Optionally, the outer peripheral walls of the fixed contact and the movable contact are provided with insulating outer skins.

Optionally, the extraction piston further comprises a sealing ring disposed at the left end of the connecting shaft section.

Optionally, the air exhaust device further comprises a motor box, a motor is arranged in the motor box, a driving gear is arranged on an output shaft of the motor, transmission teeth are arranged on the outer circular surface of the air exhaust rotary seat to enable the driving gear to drive the air exhaust rotary seat to rotate, and a motor switch is arranged on the shell;

the shell is also provided with a call key, and when the call key of the other mining intrinsic safety type network talkback public address telephone connected with the shell works, the mining intrinsic safety type network talkback public address telephone enables a fixed contact and a moving contact of the mining intrinsic safety type network talkback public address telephone to be connected.

The invention has the beneficial effects that: the mining intrinsic safety type network talkback public address telephone is provided with the power connector with the vacuum cavity, the control device comprising the first small ball, the second small ball and the elastic membrane is arranged in the power connector, the positions of the first small ball and the second small ball are changed through the deformation of the elastic membrane, and then the movement of the conductive rod is controlled, so that the change of the vacuum degree in the vacuum cavity is reflected, meanwhile, the safety of the public address telephone is ensured as much as possible, and the occurrence of coal mine safety accidents is prevented.

The invention also provides an air extractor, when the power connector is not seriously damaged, the vacuum degree of the vacuum cavity is improved through vacuum pumping again, arcing is avoided, the movable contact and the static contact are separated after the positions of the first small ball and the second small ball are adjusted, and parts are convenient to replace.

Drawings

In order to illustrate more clearly the embodiments of the invention or the solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained by those skilled in the art without inventive exercise from these drawings, it being understood that these drawings are not necessarily drawn to scale.

Fig. 1 is a schematic structural diagram of a mining intrinsic safety type network talkback public address telephone.

Fig. 2 is a schematic diagram of the joint between the fixed contact and the movable contact in the normal state of the power connector of the present invention.

Fig. 3 is a schematic diagram illustrating a separation between a fixed contact and a movable contact in a normal state of the power connector of the present invention.

Fig. 4 is a schematic diagram illustrating the connection between the fixed contact and the movable contact when the power connector is broken but not lower than the safety threshold.

Fig. 5 is a schematic diagram illustrating the separation of the fixed contact and the movable contact when the power connector is broken but not lower than the safety threshold.

Fig. 6 is a schematic diagram of the joint between the fixed contact and the movable contact when the power connector is lower than the safety threshold.

Fig. 7 is a schematic diagram of the joint between the fixed contact and the movable contact when the power connector is lower than the safety threshold.

Fig. 8 is a partially enlarged view of a portion a in fig. 2.

Fig. 9 is a partial enlarged view of fig. 7 at B.

Figure 10 is a front view of the extraction piston of the present invention.

Figure 11 is a left side view of the extraction piston of the present invention.

Figure 12 is a rear view of the extraction piston of the present invention.

In the figure: 1. a call key; 2. a motor switch; 3. a power supply connector; 4. a loudspeaker; 5. a motor box; 6. a housing; 100. air suction rotary seat; 101. a guide block; 102. a transmission tooth; 200. a ceramic tube; 300. a movable end sealing cover; 301. an air duct; 302. a communicating hole; 303. a tapered hole; 304. a slide hole; 400. a stationary end sealing cover; 401. an exhaust hole; 403. a mounting cavity; 500. a bellows; 600. a first check valve; 700. a second one-way valve; 800. static contact; 801. a static conductive rod; 802. an insulating sheath; 900. a moving contact; 901. a movable conductive rod; 903. a limiting groove; 1000. an elastic insulating gasket; 1100. a first pellet; 1101. a second pellet; 1200. a shield case; 1201. an annular flange; 1300. an air extraction piston; 1301. a cam slot; 1302. an air exhaust hole; 1303. a sealing flange; 1304. a seal ring; 1305. a guide groove; 1306. connecting the shaft sections; 1400. a sealing plug; 1401. a retainer ring; 1402. an elastic film.

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.

As shown in fig. 1 to 12, the mining intrinsic safety type network talkback public address telephone (hereinafter referred to as talkback public address telephone) of the present invention includes a casing 6, and a loudspeaker 4, a power supply and a power supply connector 3 are arranged in the casing 6. The power connector 3 includes an insulating housing which is horizontally disposed in the housing 6 and has a sliding hole 304 extending horizontally in a side wall thereof, a conductive member, a bellows 500, and a control device. The conductive component comprises a static contact 800, a moving contact 900, a static conductive rod 801 and a moving conductive rod 901; the fixed contact 800 and the movable contact 900 are correspondingly arranged in the insulating shell, the fixed contact 801 is fixedly arranged and the fixed contact 800 is arranged at the inner end of the fixed contact 801, the movable contact 900 is connected with the movable contact 900 and is slidably arranged in the insulating shell through the sliding hole 304, and the fixed contact 801 and the movable contact 901 are respectively communicated with the loudspeaker 4 and the power supply.

The bellows 500 is sleeved on the movable conductive rod 901, and one end of the bellows is connected to the movable contact 900, and the other end of the bellows is connected to the insulating housing to close the sliding hole 304, thereby defining a vacuum chamber with the insulating housing. The control device is configured to allow the movable conducting rod 901 to slide outwards along the insulating shell to separate the movable contact 900 from the static contact 800 when the vacuum degree in the vacuum chamber is higher than or equal to a preset threshold value, and block the movable conducting rod 901 from sliding outwards to keep the movable contact 900 in contact with the static contact 800 when the vacuum degree in the vacuum chamber is lower than the preset threshold value. It should be noted that the corrugated tube 500 is a thin-walled sealing element made of stainless steel with a thickness of 0.1-0.2 mm, and in the process of opening and closing the moving contact 900 and the static contact 800, the corrugated tube 500 is under the stretching action, so that the moving conductive rod 901 is ensured to move within a certain range and maintain the high vacuum function in the vacuum cavity for a long time, and the power connector 3 is ensured to have a very long mechanical life. The fatigue life of the corrugated tube 500 is related to the heating temperature of the working condition, and after the power connector 3 breaks off a large short-circuit current, the waste heat of the conductive component is transferred to the corrugated tube 500, so that the temperature of the corrugated tube 500 is increased, and when the temperature rise reaches a certain degree, the fatigue strength of the corrugated tube 500 is affected.

The talkback public address telephone is arranged at different stations and different areas in a coal mine, the shell is also provided with a talk button 1, when the talk button 1 of another talkback public address telephone connected with the station works, the movable contact 900 of the talkback public address telephone at the station moves under the action of the electromagnet, so that the fixed contact 800 and the movable contact 900 are attracted, the loudspeaker 4 is started to receive the broadcast, after the broadcast is finished, the electromagnet is powered off, the movable contact 900 moves in the reverse direction, so that the movable contact 900 is separated from the fixed contact 800, and the loudspeaker 4 is closed. In the process of separating the moving contact 900 and the static contact 800, air may be broken down to generate an arc, and due to the action of the vacuum cavity in the power connector 3, the environment in which the moving contact 900 and the static contact 800 are located is in a high vacuum state when the moving contact and the static contact are separated, so that the air is broken down to release a large amount of heat when the contacts are disconnected, and the generation of the arc is suppressed. When the corrugated pipe 500 is damaged or the insulating shell is not sealed tightly, and the vacuum degree of the vacuum cavity in the power connector 3 is lower than the safety threshold, the moving contact 900 and the static contact 800 cannot be separated, so that electric arcs cannot be generated, the safety of the talkback sound amplifying telephone is ensured to the maximum extent, and coal mine safety accidents are prevented from being caused. After the moving contact 900 and the fixed contact 800 are stuck, the loudspeaker 4 is in a connected state (or can generate abnormal sound), and subsequent parts can be repaired and replaced.

In this embodiment, the insulating housing is horizontally provided with a gas channel 301 and a communication hole 302. The air duct 301 is located above the slide hole 304 and communicates the vacuum chamber with the external atmosphere, and the communication hole 302 is vertically provided and communicates the middle of the air duct 301 with the slide hole 304. A limiting groove 903 with an upward opening is formed in the outer peripheral wall of the moving contact rod 901, and when the moving contact 900 contacts the static contact 800, the communicating hole 302 and the limiting groove 903 are correspondingly formed.

The control device comprises a first small ball 1100, a second small ball 1101 and an elastic membrane 1402, wherein the elastic membrane 1402 is arranged in the air duct 301 and swells into the vacuum cavity under the action of air pressure difference to form a pit with an outward opening. The communicating hole 302 is positioned at the swelling outer side of the elastic membrane 1402, the first small ball 1100 is positioned in the pit, the second small ball 1101 is positioned in the communicating hole 302, the first small ball 1100 and the second small ball 1101 are connected through a pull rope, and the diameter of the first small ball 1100 is larger than the aperture of the communicating hole 302. When the vacuum degree in the vacuum chamber is lower than a preset threshold value, the elastic membrane 1402 deforms and decreases, the first small ball 1100 is pushed outwards, the second small ball 1101 falls down by means of the gravity of the second small ball 1101, the movable conductive rod 901 moves outwards, the second small ball 1101 drives the first small ball 1100 to fall into the top end of the communication hole 302, and the second small ball 1101 falls into the limiting groove 903 to block the movable conductive rod 901 from moving relative to the insulating shell. For the convenience of installation and sealing, a sealing plug 1400 is arranged in the air duct 301, an elastic membrane 1402 is arranged in the sealing plug 1400, a retainer 1401 is arranged in the sealing plug 1400 and positioned outside the elastic membrane 1402 to limit the movement of the elastic membrane 1402, and the retainer 1401 is provided with a through hole in the center to facilitate the passage of the second small ball 1101. The lower end of the communication hole 302 is provided with a tapered hole 303 to further secure the second ball 1101 in a stuck state. As shown in fig. 4 and 5, when the corrugated pipe 500 is damaged or the insulating housing is not sealed tightly, but the vacuum degree in the vacuum chamber is not lower than a safety threshold, the deformation amount of the elastic membrane 1402 is smaller, the depth of the second small ball 1101 falling into the limiting groove 903 is not enough to affect the movement of the movable conducting rod 901, and the movable conducting rod 901 overcomes the obstruction of the second small ball 1101 to drive the movable contact 900 and the static contact 800 to be normally separated and combined.

In this embodiment, this public address telephone of talkbacking still includes air exhaust device, and air exhaust device is including bleeding swivel mount 100 and air exhaust piston 1300, and air exhaust piston 1300 installs in the left end of insulating casing through first cooperation structure slidable, and air exhaust swivel mount 100 rotationally installs in insulating casing along the horizontal direction to drive air exhaust piston 1300 through second cooperation structure and remove along insulating casing.

The insulating casing corresponds respectively on with the piston 1300 of bleeding and is provided with first check valve 600 and the second check valve 700 that hinder outside gas to get into the vacuum chamber, first check valve 600 and second check valve 700 are linked together, when bleeding the transposition 100 and driving the piston 1300 of bleeding and remove to the vacuum chamber is inside, the gas in the vacuum chamber is discharged along first check valve 600 and second check valve 700, and when bleeding transposition 100 and driving the piston 1300 of bleeding and moving to the direction of keeping away from the vacuum chamber, the volume increase of vacuum chamber, and then improve the vacuum in the vacuum chamber. When the moving contact 900 and the static contact 800 are locked, the air extracting rotary base 100 and the air extracting piston 1300 are relatively rotated, the vacuum cavity is vacuumized, the vacuum degree of the vacuum cavity is reduced, arcing is avoided, and after the positions of the first small ball 1100 and the second small ball 1101 are adjusted, the moving contact 900 and the static contact 800 are disconnected, and parts are maintained or replaced. If the power connector 3 is seriously damaged and the vacuum cavity can not be vacuumized, the power can be disconnected to replace parts.

In this embodiment, the insulating housing includes a ceramic tube 200, a stationary end sealing cover 400 and a moving end sealing cover 300, the ceramic tube 200 is horizontally disposed, the stationary end sealing cover 400 is disposed at the left end of the ceramic tube 200, and the moving end sealing cover 300 is disposed at the right end of the ceramic tube 200. The center of the stationary end sealing cover 400 is provided with a mounting cavity 403 and a shaft hole which are sequentially connected from right to left, the air-extracting piston 1300 comprises a connecting shaft segment 1306 and a sealing flange 1303 which are sequentially connected from left to right, the connecting shaft segment 1306 penetrates through the shaft hole, the sealing flange 1303 is positioned in the mounting cavity 403, the air-extracting rotary seat 100 is sleeved on the connecting shaft segment 1306, and the static conductive rod 801 penetrates through the air-extracting piston 1300 and extends out of the air-extracting rotary seat 100. The air duct 301, the communication hole 302 and the sliding hole 304 are all provided on the movable end sealing cover 300.

The first fitting structure includes a guide groove 1305 horizontally provided in the outer peripheral wall of the sealing flange 1303, and the inner peripheral wall surface of the mounting cavity 403 is provided with a guide projection which is located in the guide groove 1305 to block the circumferential rotation of the extraction piston 1300.

The second cooperation structure includes guide block 101 and cam groove 1301, and guide block 101 sets up at the inner peripheral wall face of bleeding swivel mount 100, and cam groove 1301 sets up a week and end to end slope extension around the peripheral wall face of connecting shaft segment 1306, and guide block 101 is located cam groove 1301 to drive when bleeding swivel mount 100 rotates and bleed piston 1300 removes.

In this embodiment, the stationary end sealing cover 400 is provided with a plurality of exhaust holes 401, the exhaust holes 401 are communicated with the external atmosphere and the installation cavity 403, and the first one-way valve 600 is correspondingly installed in the exhaust holes 401. The sealing flange 1303 is provided with a plurality of horizontally extending air suction holes 1302, and the second check valves 700 are correspondingly arranged in the air suction holes 1302.

In this embodiment, a shielding case 1200 is further disposed in the insulating housing, and the shielding case 1200 is mounted on the static conductive rod 801 and covers the static contact 800, the moving contact 900 and the outer side of the corrugated tube 500, so as to prevent a large amount of metal vapor and liquid droplets generated by the static contact 800 and the moving contact 900 during the arcing process from splashing and polluting the inner wall of the insulating housing. The static contact 800 is movably mounted on the static conductive rod 801, so that the static contact 800 has a certain movement range, an elastic insulating gasket 1000 is arranged between the static contact 800 and the shielding case 1200, the elastic insulating gasket 1000 is in a completely compressed state during normal operation, and when the moving contact 900 starts to move outwards, the static contact 800 can move a distance along with the moving contact 900 to keep contact.

In this embodiment, the plurality of annular flanges 1201 are arranged on the inner peripheral wall surface of the shield 1200 at intervals in the horizontal direction, and the annular flanges 1201 can greatly absorb metal droplets and metal dust generated when the static contact 800 and the moving contact 900 are disconnected, so that the shielding effect of the shield 1200 is further improved, rapid extinguishing of an arc is facilitated, and re-ignition of the arc is prevented.

The outer peripheral walls of the static contact 800 and the moving contact 900 are provided with insulating outer skins 802, so that the discharge of the outer peripheries of the static contact 800 and the moving contact 900 to other electric conductors can be prevented.

The extraction piston 1300 further comprises a sealing ring 1304, the sealing ring 1304 being arranged at the left end of the connecting shaft segment 1306 to close the central bore of the extraction piston 1300 and improve the sealing of the vacuum chamber.

In this embodiment, this public address intercom still includes motor box 5, and motor box 5 sets up on casing 6 and corresponds the installation of power connector 3, is provided with the motor in the motor box 5, is provided with drive gear on the output shaft of motor, is provided with drive tooth 102 on the excircle face of the swivel mount 100 of bleeding to make drive gear drive bleed swivel mount 100 rotate, still is provided with motor switch 2 on casing 6, with control motor start or close, and then start or close air exhaust device.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.