WO2013181916A1 - Refrigerator and control method - Google Patents

Abstract

Disclosed is a refrigerator, comprising a refrigeration compartment and a freezer compartment. A first refrigeration evaporator (1) and a second refrigeration evaporator (2) are provided in the refrigeration compartment. A freezer evaporator (3) is provided in the freezer compartment. The first refrigeration evaporator (1) and the second refrigeration evaporator (2) after being coupled in parallel are coupled in series with the freezer evaporator (3). Two mutually independent refrigerant circulation loops are formed by means of a two-position three-way electromagnetic valve (4) connected between a condenser (5) and a compressor (6). A control unit switches the two-position three-way electromagnetic valve (4). The refrigerator can switch the refrigeration compartment to a micro-freezer compartment according to user requirements, on the one hand meeting user requirements on the freezer compartment under special circumstances and on the other hand, food in the micro-freezer compartment does not require a very long time to defrost, thus the refrigerator does not need the addition of a variable temperature chamber. The structure is simple and easy to realise.

Description

 Refrigerator and control method

The present application claims the priority of the Chinese Patent Application No. 201210182265.9, the entire disclosure of which is incorporated herein by reference.

[Technical Field]

The present invention relates to a refrigerator, and more particularly to a refrigerator and a control method for switching a micro-freezer in a refrigerating compartment.

 【Background technique】

At present, the two refrigerators on the market are mostly single-system temperature control. Generally, the above is a refrigerating room. The lower part is a freezer compartment. The two compartments are controlled by a refrigeration system. The temperature of the refrigerating compartment is generally controlled by a mechanical knob to 0. -10 degrees, mainly used for food preservation; the temperature of the freezer is maintained below -18 degrees, and the items are stored for a long time. At present, consumers are accustomed to using a large amount of frozen food to meet the holiday demand during the Spring Festival and other festivals, and there is less demand for the cold storage room; thus the daily freezer room space is obviously insufficient, which makes the use of the refrigerator limited and cannot meet the needs of consumers.

In the traditional single-system temperature-controlled two-door refrigerator, the following shortcomings exist: 1. The temperature of the refrigerating compartment can only be controlled within the range of 0-10 degrees, and the food cannot be frozen, and the storage period is 3-5 days. 2. The meat frozen in the freezing room below -18 degrees needs to be cut for a long time, so that the user is very inconvenient to cook.

At present, some refrigerators have added a greenhouse to increase the freezer space of the refrigerator, and accordingly, the overall structure of the refrigerator needs to be changed, the volume of the refrigerator is increased, and the cost is increased.

Based on this, how to invent a refrigerator, which can switch the refrigerating chamber into a micro-freezing chamber according to the needs of the user, on the one hand, satisfies the user's demand for the freezing chamber under special circumstances, and on the other hand, the food in the micro-freezing chamber does not need to be long. Timed ice is a major problem solved by the present invention.

 [Summary of the Invention]

In order to solve the problem that the existing two-door refrigerator freezer does not have a freezing function, and that adding a greenhouse will increase the volume and cost of the refrigerator, and it is difficult to realize, a refrigerator in which the refrigerator compartment can be switched into a micro-freezing compartment is provided. The setting of the cold storage room has different refrigeration intervals, no need to add a greenhouse, and the structure is simple and easy to implement.

In order to solve the above technical problem, the present invention is implemented by the following technical solutions:

A refrigerator comprising a refrigerating chamber and a freezing chamber, wherein a first refrigerating evaporator and a second refrigerating evaporator are disposed in the refrigerating chamber, and a freezing evaporator is disposed in the freezing chamber, the first refrigerating evaporator and the first The two refrigerated evaporators are connected in series with the refrigerating evaporator, and are connected by a two-position three-way solenoid valve to form two independent refrigerant circulation loops between the condenser and the compressor, and the control unit pairs the two-way three-way electromagnetic The passage of the valve is switched.

Further, a one-way shut-off valve is further included; the inlet of the two-position three-way solenoid valve is connected to the condenser, and one outlet of the two-position three-way solenoid valve is connected to the first capillary and then connected to the second refrigerating evaporator The other outlet is connected to the inlet of the first refrigerating evaporator on the one hand and the inlet of the second evaporator via the one-way shut-off valve.

Alternatively, the refrigerator further includes a one-way shut-off valve, and an inlet of the two-position three-way solenoid valve is connected to the condenser, and an outlet of the two-position three-way solenoid valve is connected to the first capillary and the second The refrigerated evaporator is connected, and the other outlet is connected to the inlet of the second refrigerating evaporator on the one hand and the inlet of the first evaporator through the one-way shut-off valve.

Wherein, the control unit can be a computer board or a mechanical switch.

A refrigerator control method includes the following steps:

(1), the control unit receives the control command, and determines that if the command is to control the refrigerating compartment to perform the refrigerating state, step (2) is performed, if the command is to control the refrigerating compartment to perform the micro-frozen state, then step (3) is performed;

(2), the two-way three-way solenoid valve is turned on in the direction of the second refrigerating evaporator, and the two-way three-way solenoid valve is disconnected to the first refrigerating evaporator, and returns to step (1), at this time, the refrigerant circulation circuit The flow direction of the refrigerant is a two-position three-way solenoid valve, a second refrigerating evaporator, a refrigerating evaporator, a compressor, and a condenser;

(3) The two-way three-way solenoid valve is simultaneously turned on in the direction of the first refrigerating evaporator and the second refrigerating evaporator, and returns to step (1), at which time the refrigerant flow direction of the refrigerant circulation circuit is: two-third The solenoid valves are respectively flowed to the first refrigerating evaporator and the second refrigerating evaporator, and then merged into the refrigerating evaporator, the compressor, and the condenser in sequence.

Further, when the refrigerating state command is executed in the refrigerating compartment, the following substeps are further included in the step (2):

(21), detecting the temperature of the temperature sensing tube of the refrigerating compartment, and determining that the temperature value of the temperature sensing tube of the refrigerating compartment reaches the limit value, controlling the opening and closing of the compressor;

(22) When the compressor is stopped, the ambient temperature value is detected, and when the ambient temperature value reaches the limit value, the low temperature compensation heating wire is controlled to be turned on for low temperature compensation.

Still further, in the refrigerating chamber when the micro-frozen state command is executed, the step (3) further includes the step of turning off the low-temperature compensation heating wire.

Wherein, the control unit is a computer board or a mechanical switch.

Compared with the prior art, the advantages and positive effects of the present invention are that the refrigerator of the present invention can switch the refrigerating chamber into a micro-freezing chamber according to the needs of the user, and on the other hand, satisfies the user's demand for the freezing chamber under special circumstances, and does not need Changing the space structure of the refrigerator, on the other hand, the food in the micro-freezing room does not need to be iced for a long time, which brings great convenience to the user.

Other features and advantages of the present invention will become more apparent from the detailed description of the embodiments.

 [Description of the Drawings]

1 is a system schematic diagram of an embodiment of a refrigerator according to the present invention;

2 is a schematic diagram of another system of the refrigerator according to the present invention;

3 is a schematic diagram of a control of the refrigerator proposed by the present invention;

4 is another schematic diagram of control of the refrigerator proposed by the present invention;

Figure 5 is a schematic diagram of control of the refrigerator proposed by the present invention;

Figure 6 is a diagram showing another control principle of the refrigerator proposed by the present invention.

 【detailed description】

The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

Embodiment 1 Referring to FIG. 1, a refrigerator according to this embodiment includes a refrigerating chamber and a freezing chamber (not shown in FIG. 1), and a first refrigerating evaporator 1 and a second refrigerating evaporation are disposed in the refrigerating chamber. The refrigerator 2 is provided with a freezing evaporator 3 in the freezing chamber, and the first refrigerating evaporator 1 and the second refrigerating evaporator 2 are connected in series with the freezing evaporator 3 in series, and are connected by a two-position three-way solenoid valve 4 Two mutually independent refrigerant circulation circuits are formed between the condenser and the compressor, and the control unit (not shown in FIG. 1) switches the passage of the two-position three-way solenoid valve 4. In the present embodiment, by using one of the first refrigerating evaporator 1 and the second refrigerating evaporator 2, a large refrigerating evaporator having a large refrigerating capacity (similar to a refrigerating evaporator) is used to control the two-way tee. The passage of the solenoid valve 4, in turn, controls the circulation loop of the selected refrigerant. When the refrigerant circulation loop passes through the refrigerating evaporator with a small refrigeration capacity, the temperature of the refrigerating compartment can be controlled in the range of 0 to 10 ° C, and has a refrigerating function when the refrigerant When the circulation loop passes through the refrigerating evaporator with large refrigeration capacity, the temperature of the refrigerating compartment can be controlled in the range of -5 to -10 °C, and has a micro-freezing function. At this time, the refrigerating compartment is converted into a micro-freezing compartment, and it is not necessary to increase the volume of the refrigerator, which is advantageous for saving. cost.

In addition, in the present embodiment, the passage of the two-position three-way solenoid valve 4 to the second refrigerating evaporator 2 may be normally open, when the passage of the two-position three-way solenoid valve 4 to the first refrigerating evaporator 1 is closed. At this time, the flow direction of the refrigerant is a two-position three-way solenoid valve 4, a second refrigerating evaporator 2, a refrigerating evaporator 3, a compressor 6, and a condenser 5, and the refrigerating chamber is in a refrigerated state. When the passage of the two-position three-way solenoid valve 4 to the first refrigerating evaporator 1 is turned on, the refrigerant flows to the first refrigerating evaporator 1 and the second refrigerating evaporator 2 at the two-position three-way solenoid valve 4, respectively. The first refrigerating evaporator 1 and the second refrigerating evaporator 2 can be simultaneously cooled, and the temperature of the refrigerating compartment can be lowered, and the function of freezing the refrigerating compartment can be realized without using a large refrigerating capacity of one of the refrigerating evaporators.

The control unit may be a computer board or a mechanical switch. When the control unit is a computer board, as shown in FIG. 3, it is a control schematic diagram of the computer board, and the computer board H is connected with a refrigerating sensor T1, a ring temperature sensor T2, two The three-way solenoid valve 4, the compressor 6, and the low temperature compensation heating wire R, the computer board H is provided with a switching button (not shown in FIG. 3), wherein the refrigerating sensor T1 is used for detecting the temperature of the refrigerating chamber, and the ring temperature sensor T2 is used. When detecting the ambient temperature, when the refrigerating compartment is switched to the refrigerating state, the refrigerating sensor T1 sends the detected refrigerating compartment temperature to the computer board H, and the computer board H controls the opening and closing of the compressor 6, in order to prevent the ambient temperature from being too low, When the compressor 6 does not start and cannot meet the cooling requirements of the freezer compartment, the ambient temperature sensor T2 detects the ambient temperature and sends it to the computer board H. If the ambient temperature is below the limit (generally 16 °C), the computer board H controls the low temperature. The compensation heating wire is turned on, which in turn can be controlled to cause the compressor 6 to start. When the refrigerating chamber is switched to the micro-frozen state, the computer board switches another control parameter for controlling the refrigerating sensor T1, and simultaneously closes the low-temperature compensation heating wire, and controls the two-way three-way solenoid valve 4 to the second capillary tube 9. The passage is turned on to allow the first refrigerating evaporator 1 and the second refrigerating evaporator 2 to operate simultaneously. When the control unit is an electromechanical switch, as shown in FIG. 4, by setting a thermostat D1, a set of interlocking switches K1, K2, and K3 are respectively connected in parallel with the illustrated thermostat D1, and the parallel circuit and the compression are performed. The machine is connected in series, and the low temperature compensation heating wire R1 and the magnetic sensitive switch K4 are connected in series on the branch road of K1. The temperature control tube heating wire R2 is connected in series on the branch road of K2, and two three-way electromagnetic valves 4 are connected in series on the branch road of K3. And the series branch is connected in parallel with the compressor 6. The on-off state of the interlocking switch K1 is opposite to the on-off state of K2 and K3. When K1 is closed and K2 and K3 are disconnected, the refrigerator freezer is in a refrigerated state, and the thermostat D1 controls the on-off according to the perceived temperature. Further, the compressor 6 is controlled to be turned on and off, and the magnetic sensitive switch K4 is closed when it is lower than a certain temperature limit (for example, 16 ° C), and then the branch of K1 is turned on, and the low temperature compensation heating wire R1 is operated to perform heating to prevent the outside. The ambient temperature is too low and the freezer compartment does not reach the freezing temperature. When K1 is disconnected, K2 and K3 are turned on, the thermostat temperature sensing tube heating wire R2 works, the low temperature compensation heating wire R1 is disconnected, and the thermostat temperature heating tube heating wire R2 is used to heat the thermostat. By using the method of temperature compensation of the temperature heating tube heating wire, the temperature controller D1 is operated, and the compressor 6 is operated.

Embodiment 2 This embodiment provides another specific embodiment. Referring to FIG. 2, the refrigerator further includes a one-way stop valve 7, an inlet of the two-position three-way solenoid valve 4, and the condensation. The device 5 is connected, one outlet of the two-position three-way solenoid valve 4 is connected to the first capillary tube 8 and then connected to the second refrigerating evaporator 2, and the other outlet is connected to the second capillary tube 9 on the one hand and the first refrigerating evaporator 1 In addition, the inlet connection is connected to the inlet of the second evaporator 2 via the one-way shut-off valve 7 described.

In the present embodiment, by providing a one-way shutoff valve 7, the flow rate of the refrigerant is more easily controlled, and the refrigerant flowing to the second refrigerating evaporator 2 is prevented from flowing back to the first refrigerating evaporator 1, and the control unit pairs the two The passage of the three-way solenoid valve 4 is switched. At this time, the two passages of the two-position three-way solenoid valve 4 to the first capillary tube 8 and the second capillary tube 9 can only be turned on in one state, and cannot be simultaneously guided. Turning on or off at the same time, therefore, when the passage of the two-position three-way solenoid valve 4 to the first capillary tube 8 is turned on, that is, the two-position three-way solenoid valve 4 to the second refrigerating evaporator 2 are turned on, at this time, the refrigerant The flow direction is, in order, a two-position three-way solenoid valve 4, a first capillary tube 8, a second refrigerating evaporator 2, a refrigerating evaporator 3, a compressor 6, and a condenser 5, at which time the refrigerating chamber is in a refrigerated state. When the passages of the two-way three-way solenoid valve 4 to the second capillary tube 9 are turned on, the one-way shutoff valve 7 is simultaneously controlled to be turned on, at which time the two-way three-way solenoid valve 4 to the first capillary tube 8 are closed, and the refrigerant passes through the second. The capillary 9 is divided into two paths, one through the one-way shutoff valve 7 to the second refrigerating evaporator 2, and the other flow to the first refrigerating evaporator 1, that is, the first refrigerating evaporator 1 and the second refrigerating evaporator 2 are connected in parallel Work, with the addition of a small first refrigerated evaporator 1 to achieve a switching low temperature function that would require a large refrigerated evaporator.

It should be noted that the control unit may be a computer board or a mechanical switch. When the control unit is a computer board, as shown in FIG. 6 , it is a control schematic diagram of the computer board, and the computer board H is connected with a refrigerating sensor T1 and a ring. Temperature sensor T2, two-position three-way solenoid valve 4, compressor 6, one-way stop valve 7, and low temperature compensation heating wire R, and a switching button (not shown in FIG. 6) is provided on the computer board H, wherein the refrigerating sensor T1 is used. The temperature sensor T2 is used to detect the ambient temperature. When the refrigerator is switched to the refrigerated state, the refrigerating sensor T1 sends the detected refrigerating chamber temperature to the computer board H, and the computer board H controls the compressor 6. To stop and stop, in order to prevent the ambient temperature from being too low, the compressor 6 does not start and cannot meet the refrigeration requirements of the freezer compartment, the ambient temperature sensor T2 detects the ambient temperature and sends it to the computer board H if the ambient temperature is below the limit (general At 16 ° C), the computer board H controls the low temperature compensation heating wire to be turned on, and thus can be controlled to start the compressor 6. When the refrigerating chamber is switched to the micro-frozen state, the computer board switches another control parameter for controlling the refrigerating sensor T1, and simultaneously closes the low-temperature compensation heating wire, and controls the two-way three-way solenoid valve 4 to the second capillary tube 9. The passage is turned on to allow the first refrigerating evaporator 1 and the second refrigerating evaporator 2 to operate simultaneously.

The third embodiment, the system structure of the embodiment is the same as that of the second embodiment. Referring to FIG. 2, the specific system principle is not described herein. The difference is that the control unit of the embodiment uses a mechanical switch, and the name of each component can be implemented by reference. In the example of the component name in Fig. 4, when the system further includes the one-way stop valve 7, as shown in Fig. 5, when the refrigerating chamber is switched to the refrigerating state, K3 is disconnected, and the one-way shut-off valve 7 is closed to Preventing the recirculation of the refrigerant, when the refrigerating chamber is switched to the micro-frozen state, the two-position three-way solenoid valve 4 is turned on and the one-way shut-off valve 7 is turned on, and the two-way three-way solenoid valve 4 is closed to the first capillary tube 8 The refrigerant passes through the second capillary tube 9, and then splits into two paths, respectively flowing to the first refrigerating evaporator 1 and through the one-way shutoff valve 7 to the second refrigerating evaporator 2, so that the first refrigerating evaporator 1 and the second refrigerating evaporator 2 work at the same time.

Embodiment 4, this embodiment provides a third specific embodiment of the refrigerator. Referring to FIG. 7, the refrigerator further includes a one-way stop valve 7, an inlet of the two-position three-way solenoid valve 4, and the The condenser 5 is connected, one outlet of the two-position three-way solenoid valve 4 is connected to the first capillary tube 8 and then connected to the second refrigerating evaporator 2, and the other outlet is connected to the second capillary tube 9 after being cooled with the second refrigeration. The inlet connection of the device 2 is connected to the inlet of the first evaporator 1 via the one-way shut-off valve 7 on the other hand.

In the present embodiment, by providing a one-way shutoff valve 7, the flow rate of the refrigerant is more easily controlled, and the refrigerant flowing to the second refrigerating evaporator 2 is prevented from flowing back to the first refrigerating evaporator 1, and the control unit pairs the two The passage of the three-way solenoid valve 4 is switched. At this time, the two passages of the two-position three-way solenoid valve 4 to the first capillary tube 8 and the second capillary tube 9 can only be turned on in one state, and cannot be simultaneously guided. Turning on or off at the same time, therefore, when the passage of the two-position three-way solenoid valve 4 to the first capillary tube 8 is turned on, that is, the two-position three-way solenoid valve 4 to the second refrigerating evaporator 2 are turned on, at this time, the refrigerant The flow direction is, in order, a two-position three-way solenoid valve 4, a first capillary tube 8, a second refrigerating evaporator 2, a refrigerating evaporator 3, a compressor 6, and a condenser 5, at which time the refrigerating chamber is in a refrigerated state. When the passages of the two-way three-way solenoid valve 4 to the second capillary tube 9 are turned on, the one-way shutoff valve 7 is simultaneously controlled to be turned on, at which time the two-way three-way solenoid valve 4 to the first capillary tube 8 are closed, and the refrigerant passes through the second. The capillary 9 is divided into two paths, one flow to the second refrigerating evaporator 2, and the other flow to the first refrigerating evaporator 1 via the one-way shutoff valve 7, that is, the first refrigerating evaporator 1 and the second refrigerating evaporator 2 are connected in parallel. Work, with the addition of a small first refrigerated evaporator 1 to achieve a switching low temperature function that would require a large refrigerated evaporator.

The fifth embodiment is based on the refrigerators in the first embodiment to the fourth embodiment. The embodiment provides a refrigerator control method, including the following steps:

S1, the control unit receives the control command, and determines that if the command is to control the refrigerating compartment to perform the refrigerating state, step S2 is performed, if the command is to control the refrigerating compartment to perform the micro-freezing state, step S3 is performed;

S2, the two-way three-way solenoid valve is turned on in the direction of the second refrigerating evaporator, and the two-way three-way solenoid valve is disconnected to the first refrigerating evaporator, and returns to step S1, where the refrigerant flow direction of the refrigerant circulation circuit In turn, it is a two-position three-way solenoid valve, a second refrigerating evaporator, a refrigerating evaporator, a compressor, and a condenser;

S3, the two-position three-way solenoid valve is simultaneously turned on in the direction of the first refrigerating evaporator and the second refrigerating evaporator, and returns to step S1, wherein the refrigerant flow direction of the refrigerant circulation circuit is: two-way three-way solenoid valves respectively The flow proceeds to the first refrigerating evaporator and the second refrigerating evaporator, and then merges into the refrigerating evaporator, the compressor, and the condenser in sequence.

It should be noted that if a capillary is provided between the solenoid valve 3 and the second refrigerating evaporator 2 or between the solenoid valve 3 and the first refrigerating evaporator 1 in the system, the refrigerant must circulate correspondingly when it circulates. Capillaries, the details are not described.

Further, when the refrigerating state command is executed in the refrigerating compartment, the following substeps are further included in step S2:

S21, detecting the temperature of the temperature sensing tube of the refrigerating compartment, and determining that the temperature value of the temperature sensing tube of the refrigerating compartment reaches the limit value, and controlling the opening and stopping of the compressor;

S22. When the compressor is stopped, when the ambient temperature value is detected, and when the ambient temperature value reaches the limit value, the low temperature compensation heating wire is controlled to be turned on for low temperature compensation.

Still further, when the refrigerating chamber executes the micro-frozen state command, the step S3 further includes the step of turning off the low-temperature compensation heating wire.

The above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and variations, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention are also The scope of protection of the present invention.

Claims (8)

1. A refrigerator comprising a refrigerating compartment and a freezing compartment, wherein a first refrigerating evaporator and a second refrigerating evaporator are disposed in the refrigerating compartment, and a freezing evaporator is disposed in the freezing compartment, the first refrigerating The evaporator and the second refrigerating evaporator are connected in series with the refrigerating evaporator, and are connected between the condenser and the compressor through a two-position three-way solenoid valve to form two mutually independent refrigerant circulation loops, and the control unit pairs the two The path of the three-way solenoid valve is switched.
2. A refrigerator according to claim 1, further comprising a one-way shut-off valve; an inlet of the two-position three-way solenoid valve is connected to said condenser, and an outlet of said two-position three-way solenoid valve is connected After the capillary is connected to the second refrigerating evaporator, the other outlet is connected to the inlet of the first refrigerating evaporator on the one hand and the inlet of the second evaporator through the one-way shut-off valve.
3. The refrigerator according to claim 1, further comprising a one-way shut-off valve, an inlet of the two-position three-way solenoid valve being connected to said condenser, and an outlet connection of said two-position three-way solenoid valve The first capillary is connected to the second refrigerating evaporator, and the other outlet is connected to the second capillary to be connected to the inlet of the second refrigerating evaporator on the one hand, and to the inlet of the first evaporator through the one-way stop valve on the other hand. .
4. The refrigerator according to any one of claims 1 to 3, wherein the control unit is a computer board or a mechanical switch.
5. A refrigerator control method, comprising the steps of:

   (1), the control unit receives the control command, and determines that if the command is to control the refrigerating compartment to perform the refrigerating state, step (2) is performed, if the command is to control the refrigerating compartment to perform the micro-frozen state, then step (3) is performed;

   (2), the two-way three-way solenoid valve is turned on in the direction of the second refrigerating evaporator, and the two-way three-way solenoid valve is disconnected to the first refrigerating evaporator, and returns to step (1), at this time, the refrigerant circulation circuit The flow direction of the refrigerant is a two-position three-way solenoid valve, a second refrigerating evaporator, a refrigerating evaporator, a compressor, and a condenser;

   (3) The two-way three-way solenoid valve is simultaneously turned on in the direction of the first refrigerating evaporator and the second refrigerating evaporator, and returns to step (1), at which time the refrigerant flow direction of the refrigerant circulation circuit is: two-third The solenoid valves are respectively flowed to the first refrigerating evaporator and the second refrigerating evaporator, and then merged into the refrigerating evaporator, the compressor, and the condenser in sequence.
6.  The refrigerator control method according to claim 5, wherein the step (2) further comprises the following substeps:

   (21), detecting the temperature of the temperature sensing tube of the refrigerating compartment, and determining that the temperature value of the temperature sensing tube of the refrigerating compartment reaches the limit value, controlling the opening and closing of the compressor;

   (22) When the compressor is stopped, the ambient temperature value is detected, and when the ambient temperature value reaches the limit value, the low temperature compensation heating wire is controlled to be turned on for low temperature compensation.
7. The refrigerator control method according to claim 5, wherein the step (3) further comprises the step of turning off the low temperature compensation heating wire.
8. The refrigerator control method according to any one of claims 5-7, wherein the control unit is a computer board or a mechanical switch.

Images