阅读说明：本技术 一种电动转辙机用接点恒温加热装置 (Contact constant temperature heating device for electric switch machine ) 是由 李旺龙 张辉 郭金贵 张明召 朴盛斌 李斌 张华剑 张振 李倩文 刘畅 于 2021-07-16 设计创作，主要内容包括：本发明公开了一种电动转辙机用接点恒温加热装置,包括接点罩、恒温加热带和盖板；中空的接点罩顶部,设置有水平分布的、透明的盖板；接点罩的四周边框上部,环绕地设置有顶部开口的恒温加热带安装槽；恒温加热带安装槽内,环绕地设置有环形的恒温加热带；接点罩的接点罩内腔,用于放置现有电动转辙机的转辙机接点座顶部上的转辙机动接点和转辙机静接点。本发明结构设计科学,能够对电动转辙机中的转辙机动接点和转辙机静接点(具体是动接点环和静接点片)进行加热,使得转辙机动接点和转辙机静接点的周围环境温度保持在较高的温度,有效防止在寒冷、潮湿环境中出现结霜问题,保证转辙机表示电路的正常运行,具有重大的生产实践意义。(The invention discloses a contact constant-temperature heating device for an electric switch, which comprises a contact cover, a constant-temperature heating belt and a cover plate, wherein the constant-temperature heating belt is arranged on the contact cover; a transparent cover plate which is horizontally distributed is arranged at the top of the hollow contact cover; a constant temperature heating belt mounting groove with an opening at the top is arranged on the upper part of the peripheral frame of the contact cover in a surrounding manner; an annular constant-temperature heating belt is arranged in the constant-temperature heating belt mounting groove in a surrounding manner; the inner cavity of the contact cover is used for placing the movable contact and the static contact of the switch machine on the top of the switch machine contact seat of the existing electric switch machine. The invention has scientific structural design, can heat the movable contact and the static contact (particularly the movable contact ring and the static contact sheet) of the switch machine in the electric switch machine, ensures that the ambient temperature of the movable contact and the static contact of the switch machine is kept at higher temperature, effectively prevents the frosting problem in cold and humid environments, ensures the normal operation of the display circuit of the switch machine, and has great production practice significance.)

1. A constant-temperature heating device for a contact of an electric switch machine is characterized by comprising a contact cover (1), a constant-temperature heating belt (2) and a cover plate (3);

wherein, the top of the hollow contact cover (1) is provided with a transparent cover plate (3) which is horizontally distributed;

a constant temperature heating belt installation groove (101) with an opening at the top is arranged on the upper part of the peripheral frame of the contact point cover (1) in a surrounding way;

wherein, an annular constant temperature heating belt (2) is arranged in the constant temperature heating belt mounting groove (101) in a surrounding manner;

wherein, the inner cavity (100) of the contact cover (1) is used for placing a switch machine contact (10) and a switch machine static contact (9) on the top of a switch machine contact seat (8) of the prior electric switch machine;

the peripheral frame of the contact point cover (1) comprises outer protective plates (11) and inner heat dissipation supporting plates (12) which are distributed at intervals;

an inner heat dissipation support plate (12) located inside the upper portion of the outer protection plate (11); and the constant temperature heating belt mounting groove (101) is positioned between the outer protection plate (11) and the inner heat dissipation support plate (12).

2. The contact constant temperature heating apparatus for an electric switch according to claim 1, wherein a plurality of heat radiating holes (102) are formed at equal intervals at both left and right ends and both front and rear ends of the inner heat radiating support plate (12), respectively.

3. The thermostatic heating device for joints of electric switch machines according to claim 1 or 2, characterized in that the cover plate (3) is fixed to the top of the peripheral frame of the joint enclosure (1) by means of a plurality of cap screws (7).

4. The contact constant temperature heating apparatus for electric switch as claimed in claim 3, wherein a screw mounting hole (104) with a cap is provided at each of four corners of the outer protection plate (11);

a cap screw through hole is formed in the cover plate (3) at a position corresponding to each cap screw mounting hole (104);

a switch machine contact base (8) on the existing electric switch machine is respectively provided with a screw connecting hole with a cap at the position corresponding to each screw mounting hole (104) with a cap;

each cap screw (7) penetrates through a corresponding cap screw through hole and a corresponding cap screw mounting hole (104) from top to bottom in sequence and is in threaded connection with the corresponding cap screw connecting hole on the switch machine contact base (8).

5. The contact constant-temperature heating apparatus for an electric switch machine as claimed in claim 1, wherein the bottom of the contact housing cavity (100) is open.

6. The contact constant temperature heating apparatus for electric switch machine as claimed in claim 2, wherein the right side of the outer protection plate (11) in the contact cover (1) is provided with a waterproof cable lock head mounting screw hole (103) which is penetrated in the lateral direction;

a waterproof cable lock head (4) is arranged on the waterproof cable lock head mounting threaded hole (103);

one end of each constant temperature heating belt lead (5) is arranged on each constant temperature heating belt (2);

the two constant temperature heating belt leads (5) are insulated at intervals;

two constant temperature heating belt leads (5) penetrate through the waterproof cable lock head (4);

two constant temperature heating belt leads (5) are fixed on the contact cover (1) through a waterproof cable lock head (4).

7. The contact thermostatic heating device for electric switch as claimed in claim 6, characterized in that the other ends of the two thermostatic heating strips (5) extend outwards after passing through the central through hole in the waterproof cable lock (4);

the outer surfaces of the two constant-temperature heating belt leads (5) are respectively wrapped with insulating layers;

and two constant temperature heating belt leads (5) are arranged in the same hollow insulating protection tube (50).

8. A thermostatic heating device for electric switches as claimed in any of claims 1 to 7, characterized by the fact that the contact cover (1) is a transparent insulating cover;

the constant temperature heating belt (2) is a PTC thermistor.

9. The contact constant-temperature heating device for electric switch machines according to any of claims 1 to 7, characterized in that the height of the constant-temperature heating zone installation groove (101) in the vertical direction is greater than the height of the constant-temperature heating zone (2) in the vertical direction.

10. The contact constant temperature heating apparatus for electric switch machine according to any one of claims 1 to 7, wherein when the constant temperature heating zone (2) is installed in the constant temperature heating zone installation groove (101), a remaining space in the inner cavity of the constant temperature heating zone installation groove (101) outside the constant temperature heating zone (2) is encapsulated with heat conductive silica gel.

Technical Field

The invention relates to the technical field of railway turnout conversion equipment, in particular to a contact constant-temperature heating device for an electric switch machine.

Background

The point switch is an important signal basic device for reliably switching the position of the turnout, changing the opening direction of the turnout, locking the switch point rail and reflecting the position of the turnout, and can well ensure the driving safety, improve the transportation efficiency and improve the labor intensity of the driving personnel.

The main functions of the electric switch machine are as follows: the switch point rail is converted and locked, the opening direction of the turnout is changed, and the position state of the switch point rail is reflected through the contact, so that the switch point rail is one of important devices for ensuring efficient, safe and orderly operation of railway transportation.

At present, after the electric switch machine is switched in place, the indication contact is required to be connected to reflect the position state of a switch rail (point rail), the contacts used by the electric switch machine for the domestic railway turnout are mostly distributed contacts, and a movable contact ring and a static contact piece are both made of conductive and elastic copper alloy.

For the movable contact ring and the static contact piece, if the movable contact ring and the static contact piece are used in a cold and humid environment, frosting can occur, after the frosting of the movable contact ring and the static contact piece, the contact resistance between the movable contact and the static contact in the electric switch machine can be rapidly increased, even the contact can not be reliably switched on, and further the indication circuit of the switch machine is in an open circuit state, so that the switch machine loses the function of switching on indication, a train can not normally pass, and the efficiency of railway transportation is seriously influenced.

Therefore, there is an urgent need to develop a technology for solving the problem of frosting of the moving contact ring and the static contact piece in the electric switch machine in the cold and humid environment, so as to ensure the normal operation of the indication circuit of the switch machine and to normally provide the indication signal for indicating the working state of the switch machine.

Disclosure of Invention

The invention aims to provide a constant-temperature heating device for a contact of an electric switch machine, aiming at the technical defects in the prior art.

Therefore, the invention provides a contact constant-temperature heating device for an electric switch, which comprises a contact cover, a constant-temperature heating belt and a cover plate, wherein the constant-temperature heating belt is arranged on the contact cover;

wherein, the top of the hollow contact cover is provided with a transparent cover plate which is horizontally distributed;

a constant temperature heating belt mounting groove with an opening at the top is arranged on the upper part of the peripheral frame of the contact cover in a surrounding manner;

wherein, an annular constant temperature heating belt is arranged in the constant temperature heating belt mounting groove in a surrounding manner;

the inner cavity of the contact cover is used for placing a switch machine movable contact and a switch machine static contact on the top of a switch machine contact seat of the existing electric switch machine;

the peripheral frame of the contact point cover comprises an outer protection plate and an inner heat dissipation support plate which are distributed at intervals;

the inner heat dissipation support plate is positioned on the inner side of the upper part of the outer protection plate; the constant temperature heating belt mounting groove is positioned between the outer protection plate and the inner heat dissipation support plate.

Preferably, the left end and the right end of the inner heat dissipation support plate and the front end and the rear end of the inner heat dissipation support plate are respectively provided with a plurality of heat dissipation holes at equal intervals.

Preferably, the cover plate is fixedly connected with the top of the peripheral frame of the contact point cover through a plurality of cap screws.

Preferably, four corners of the outer protective plate are respectively provided with a screw mounting hole with a cap;

a cap screw through hole is formed in the cover plate at a position corresponding to each cap screw mounting hole;

a switch machine contact seat on the existing electric switch machine is respectively provided with a screw connecting hole with a cap at the position corresponding to each screw mounting hole with a cap;

and each cap screw penetrates through a corresponding cap screw through hole and a corresponding cap screw mounting hole in sequence from top to bottom and is correspondingly in threaded connection with the cap screw connecting hole on the switch machine contact base.

Preferably, the bottom of the contact hood interior is open.

Preferably, a waterproof cable lock head mounting threaded hole which is transversely penetrated is formed in the right side of the outer protection plate in the contact point cover;

the waterproof cable lock head is arranged on the threaded hole;

one end of each constant-temperature heating belt is provided with two constant-temperature heating belt leads;

the two constant temperature heating belt leads are insulated at intervals;

two constant temperature heating belt leads penetrate through the waterproof cable lock head;

the two constant temperature heating belt leads are fixed on the contact cover through a waterproof cable lock head.

Preferably, the other ends of the two constant-temperature heating leading wires penetrate through a central through hole in the waterproof cable lock head and then extend outwards;

the outer surfaces of the two constant-temperature heating leading wires are respectively wrapped with insulating layers;

and two constant temperature heating tape leads are arranged in the same hollow insulating protection tube.

Preferably, the contact cover is a transparent insulating cover;

the constant temperature heating belt is a PTC thermistor.

Preferably, the height of the constant temperature heating zone installation groove in the vertical direction is greater than the height of the constant temperature heating zone in the vertical direction.

Preferably, when the constant temperature heating belt is installed in the constant temperature heating belt installation groove, the residual space outside the constant temperature heating belt is located in the inner cavity of the constant temperature heating belt installation groove, and the heat conduction silica gel is packaged.

Compared with the prior art, the technical proposal provided by the invention has the advantages that the invention provides the contact constant-temperature heating device for the electric switch machine, the structure design is scientific, the movable contact and the static contact (particularly the movable contact ring and the static contact sheet) of the switch machine in the electric switch machine can be heated, so that the ambient temperature of the switch machine movable contact and the switch machine static contact is kept at a higher temperature, the problem of frosting of the switch machine movable contact and the switch machine static contact in the electric switch machine in cold and humid environments is effectively prevented, the contact frosting of the electric switch machine caused by the reduction of the ambient temperature is avoided, and further, the problem of the indicating circuit is broken, the normal operation of the indicating circuit of the switch machine is finally ensured, the indicating signal for indicating the working state of the switch machine can be normally given, and the method has great production practice significance.

Drawings

Fig. 1 is a front view of a contact constant temperature heating device for an electric switch machine according to the present invention;

FIG. 2 is a top view of a contact constant temperature heating device for an electric switch machine according to the present invention;

fig. 3 is a top view of a contact cover in the constant temperature heating device for electric switch provided by the invention;

FIG. 4 is a cross-sectional view taken along line A-A of FIG. 3;

fig. 5 is a schematic perspective view of a contact cover in the constant temperature heating device for electric switch machine according to the present invention;

FIG. 6 is a schematic view of a connection structure of a constant temperature heating belt and a lead thereof in the constant temperature heating apparatus for a contact of an electric switch according to the present invention;

FIG. 7 is a front view of a screw with a cap in the constant temperature heating apparatus for electric switch machine according to the present invention;

fig. 8 is a front view of a contact constant temperature heating apparatus for an electric switch machine according to the present invention, which is mounted on a contact base of the switch machine;

fig. 9 is a top view of the constant temperature heating device for contact of electric switch machine, which is installed on the contact base of the switch machine, wherein the cover plate is a transparent cover plate.

In the figure: 1-a contact cover; 2-constant temperature heating zone; 3-cover plate; 4-waterproof cable lock; 5-heating the lead wire at constant temperature;

6-rubber pad; 7-cap screws; 8-switch machine contact base; 9-stationary point of switch; 10-switch mobile contacts;

100-contact cover cavity; 101-installing a constant temperature heating belt groove; 102-heat dissipation holes; 103-installing a threaded hole on the waterproof cable lock head; 104-cap screw mounting holes.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood 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.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

Referring to fig. 1 to 9, the invention provides a contact constant temperature heating device for an electric switch machine, comprising a contact cover 1, a constant temperature heating belt 2 and a cover plate 3;

wherein, the top of the hollow contact cover 1 is provided with a transparent cover plate 3 which is horizontally distributed;

a constant temperature heating belt installation groove 101 with an opening at the top is arranged on the upper part of the peripheral frame of the contact point cover 1 in a surrounding way;

wherein, the constant temperature heating belt installation groove 101 is internally provided with an annular constant temperature heating belt 2 in a surrounding way;

the contact housing interior 100 of the contact housing 1 is used for placing the switch machine contact 10 and the switch machine stationary contact 9 on top of the switch machine contact base 8 of the existing electric switch machine.

A switch machine movable contact 10 and a switch machine stationary contact 9 which are easy to frost in a low-temperature environment are arranged on the top of the switch machine contact base 8, wherein the switch machine movable contact 10 comprises a movable contact ring, and the switch machine stationary contact 9 comprises a stationary contact sheet). The switch-movable contact 10 and the switch-stationary contact 9 are components that need to be heated to avoid frost formation. Referring to fig. 8 and 9, two sets of switch machine contacts may be provided on the switch machine contact base 8, each set of contacts comprising a switch machine contact 10 and a switch machine stationary contact 9. The device of the invention can heat a group of contact groups at constant temperature.

In the invention, in particular, the peripheral frame of the contact point cover 1 comprises an outer protection plate 11 and an inner heat dissipation support plate 12 which are distributed at intervals;

an inner heat dissipation support plate 12 located at the inner side of the upper portion of the outer protection plate 11;

a constant temperature heating zone installation groove 101 located between the upper portion of the outer protection plate 11 and the inner heat dissipation support plate 12;

the constant temperature heating zone installation groove 101 has a structure with an open top and a sealed bottom. The lower portion of the contact cover 1 has an outer protection plate 11, which provides support and protection by the outer protection plate 11, and the upper portion of the contact cover 1, in addition to the outer protection plate 11, is provided with an inner heat dissipation support plate 12 inside the upper portion of the outer protection plate 11, forming a hollow structure with an open top for serving as a constant temperature heating zone installation groove 101.

Wherein, the inner heat dissipation support plate 12 has a plurality of heat dissipation holes 102 at the left and right ends and the front and rear ends, respectively.

In the present invention, the plurality of heat dissipation holes 102 are formed inside the peripheral frame of the contact cover 1 (specifically, on the inner heat dissipation support plate 12), so that the heat generated by the constant temperature heating tape 2 flows toward the inside of the contact cover 1, that is, toward the position for accommodating the contact base of the switch machine (i.e., toward the inner cavity 100 of the contact cover).

In the concrete implementation, the cover plate 3 and the top of the peripheral frame of the contact point cover 1 are fixedly connected together through a plurality (not limited to four) of cap screws 7.

In a concrete implementation, four corners of the outer protection plate 11 are respectively provided with a screw mounting hole 104 with a cap;

a cap screw through hole is formed in the cover plate 3 at a position corresponding to each cap screw mounting hole 104;

a switch machine contact base 8 of the existing electric switch machine is respectively provided with a screw connecting hole with a cap at the position corresponding to each screw mounting hole with a cap 104;

each cap screw 7 penetrates through a corresponding cap screw through hole and a corresponding cap screw mounting hole 104 from top to bottom in sequence, and then is in threaded connection with a corresponding cap screw connecting hole on the switch machine contact base 8.

In the thermostatic heating device for an electric switch according to the present invention, the nut screws 7 are fixed to the switch machine contact base 8, and as shown in fig. 8 and 9, the switch machine movable contact 10 and the switch machine stationary contact 9 on the switch machine contact base 8 can be heated after the thermostatic heating belt 2 is energized.

In the present invention, the bottom of the contact housing cavity 100 is open (i.e., not sealed) for implementation.

In the invention, in particular, a waterproof cable lock head installation threaded hole 103 which is transversely penetrated is formed in the right side of the outer protection plate 11 in the contact point cover 1;

the waterproof cable lock head mounting threaded hole 103 is provided with (for example, is inserted with) a waterproof cable lock head 4;

one end of each constant temperature heating belt lead 5 is arranged on each constant temperature heating belt 2;

the two constant temperature heating belt leads 5 are insulated at intervals;

two constant temperature heating belt leads 5 penetrate through the waterproof cable lock head 4;

two constant temperature heating tape leads 5 are fixed on the contact cover 1 through a waterproof cable lock head 4.

In concrete implementation, the other ends of the two constant-temperature heating leading wires 5 penetrate through a central through hole in the waterproof cable lock head 4 in the waterproof cable lock head mounting threaded hole 103 and then extend outwards.

It should be noted that, for the present invention, the two constant temperature heating belt leads 5 are respectively the power input positive electrode and the negative electrode of the constant temperature heating belt 2, and after being led out, the two constant temperature heating belt leads 5 are connected with an external power supply module, and are powered by the external power supply. For example, two constant temperature heating strip leads 5 may be connected to the positive and negative terminals of a single AC220V power output terminal of an RD1 type electrically heated switch snow melting system control cabinet, manufactured by tianjin railway signal, llc, located beside the switch, and the RD1 type electrically heated switch snow melting system control cabinet may output 12 single AC220V power supplies to provide power input for the present invention. Of course, the power supply module can be connected with other power supply modules according to the requirements of customers.

Specifically, the outer surfaces of the two constant-temperature heating leading wires 5 are respectively wrapped with insulating layers (of course, the insulating layers are removed at specific wiring positions, and cold-pressed terminal connectors are respectively pressed and connected);

and two constant temperature heating tape leads 5 are provided in the same hollow insulating protection tube 50.

In the present invention, the shape and size of the constant temperature heating belt installation groove 101 are matched with the shape and size of the constant temperature heating belt 2.

In the present invention, in a specific implementation, the depth (i.e., the height in the vertical direction) of the constant temperature heating zone installation groove 101 is greater than the height in the vertical direction of the constant temperature heating zone 2.

In the invention, in concrete implementation, when the constant temperature heating belt 2 is installed in the constant temperature heating belt installation groove 101, the residual space in the inner cavity of the constant temperature heating belt installation groove 101, which is positioned outside the constant temperature heating belt 2, is encapsulated with heat-conducting silica gel.

It should be noted that, according to the present invention, after the constant temperature heating tape 2 is installed in the constant temperature heating tape installation groove 101 of the contact cover, it is packaged by using heat conductive silica gel, after the packaging is completed, the cover plate 3 is installed, and the cover plate 3 and the contact cover 1 are connected together by the cap screw 7.

In the present invention, the contact cover 1 is preferably a transparent heat-resistant insulating cover, and may be made of transparent polycarbonate material, so that the state of the contact can be observed through the contact cover 1, and the contact cover has the advantages of insulation, resistance to a certain temperature and no softening.

In the present invention, the constant temperature heating tape 2 is preferably a PTC thermistor in practical implementation.

A PTC thermistor (positive temperature coefficient thermistor) is a semiconductor resistor having temperature sensitivity, and when a certain temperature (curie temperature of a material) is exceeded, the resistance value increases stepwise with the increase in temperature, and a good conductor changes to a poor conductor or even an insulator. That is, in the case of a positive temperature coefficient thermistor (PTC thermistor), the resistance value thereof shows a stepwise increase as the temperature of the PTC thermistor body increases, and the higher the temperature is, the larger the resistance value is.

In the present invention, the cover plate 3 is preferably a transparent insulating cover plate, and may be made of a transparent polycarbonate material, and the state of the contact can be observed through the cover plate 3.

Based on the above technical solution, according to the present invention, the constant temperature heating tape mounting groove 101 is provided on the contact cover, the constant temperature heating tape is mounted in the constant temperature heating tape mounting groove 101 on the contact cover, and the constant temperature heating tape is a PTC thermistor. A PTC thermistor (i.e., a PTC thermistor) is a semiconductor resistor having temperature sensitivity, and can realize constant temperature heating without a temperature control element. The inner side of the contact cover where the constant temperature heating belt is installed is provided with a heat dissipation hole, so that heat generated by the constant temperature heating belt flows to the inside of the contact cover, namely the contact position of the switch machine. Therefore, the invention can heat the points of the switch machine, so that the ambient temperature around the points is kept at a higher temperature, thereby avoiding frosting of the points caused by the decrease of the ambient temperature and further avoiding the switch machine from breaking the indicating loop.

Compared with the prior art, the contact constant-temperature heating device for the electric switch machine has the following beneficial effects:

1. the constant-temperature heating device for the contact of the electric switch machine can heat the contact of the switch machine, so that the ambient temperature around the contact is kept at a high temperature, and therefore the phenomenon that the contact is frosted due to the reduction of the ambient temperature and an indicating loop is disconnected is avoided.

2. The contact constant-temperature heating device for the electric switch machine provided by the invention adopts an independent power supply line, does not need to take power from the switch machine, and meets the railway signal safety requirement.

3. The invention provides a contact constant temperature heating device for an electric switch machine, wherein a heating belt is made of PTC thermistor materials, after the heating belt is heated to a certain temperature, the resistance value of the materials is increased in a step mode to become an insulator, the temperature is not increased continuously any more, and the damage to parts in the switch machine is avoided. Meanwhile, due to the characteristics of the PTC thermistor material, constant-temperature heating can be realized without a temperature control element, the PTC thermistor has the advantage of simple structure, and the fault of a common heating device caused by the failure of the temperature control element is avoided.

In summary, compared with the prior art, the contact constant temperature heating device for the electric switch machine provided by the invention has a scientific structural design, can heat the switch machine movable contact and the switch machine static contact (specifically, the movable contact ring and the static contact sheet) in the electric switch machine, so that the ambient temperature of the switch machine movable contact and the switch machine static contact is kept at a higher temperature, the problem of frosting of the switch machine movable contact and the switch machine static contact in the electric switch machine in a cold and humid environment is effectively prevented, the problem of contact frosting of the electric switch machine caused by the decrease of the ambient temperature is avoided, and further the problem of the indicating circuit is disconnected, the normal operation of the indicating circuit of the switch machine is finally ensured, the indicating signal for indicating the working state of the switch machine can be normally given, and the device has great production and practical significance.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.