US20120285187A1

US20120285187A1 - Automatic ice maker

Info

Publication number: US20120285187A1
Application number: US13/461,815
Authority: US
Inventors: Kenji Sugaya; Eiji Kuroda; Mariko Tanaka; Yoshitaka Yokoi; Kazufumi Yamashita
Original assignee: Nidec Servo Corp
Current assignee: Nidec Advanced Motor Corp
Priority date: 2011-05-12
Filing date: 2012-05-02
Publication date: 2012-11-15

Abstract

An automatic ice maker installed within a freezing compartment includes an ice tray arranged to hold water and make ice pieces; an ice ejecting mechanism arranged to eject the ice pieces made in the ice tray; an ice releasing heater arranged to melt surfaces of the ice pieces made in the ice tray; a thermostat arranged to detect a temperature of the ice tray and to operate at a specified temperature; and an ice storage amount detecting mechanism arranged to detect an amount of the ice pieces stored within an ice storage box. The automatic ice maker further includes a switch mechanism arranged to stop an operation of the ice releasing heater in conjunction with an operation of the ice ejecting mechanism.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to an automatic ice maker installed in a freezing compartment of a household refrigerator or the like that is arranged to repeatedly perform water supplying, ice making, and ice ejecting operations pursuant to a specified sequence.
2. Description of the Related Art
Conventionally, an automatic ice maker in a household refrigerator is usually configured to supply water from above to an ice tray arranged in a freezing compartment of the automatic ice maker, uniformly distribute the supplied water into individual ice molds of the ice tray, freeze the water into ice pieces by using ambient cold energy, melt the surfaces of the ice pieces by heating the ice tray with a heating instrument such as a heater arranged outside the ice tray, and eject the ice pieces by raking out the ice pieces with an ice ejector.
In such a conventional automatic ice maker, the ice making operation and the ice ejecting operation are realized by controlling the rotating operation of an ice ejecting lever of the ice ejector and the energizing/deenergizing of the heater in conjunction with the switching operation of a thermostat, the rotation of a motor and the resultant operation of electric contact points.
In addition, there is available an electronically-controlled automatic ice maker in which a temperature can be continuously detected using a thermistor in place of a temperature-detecting thermostat. An operation startup temperature can be appropriately set by use of a program stored in a microcomputer of a control board built in the automatic ice maker. Various kinds of operations can be set depending on the temperature change within a refrigerator.
In the conventional automatic ice maker, the rotation of the motor and the energizing/deenergizing of the heater are controlled pursuant to the thermostat operation temperature. The off-temperature of the thermostat needs to be set sufficiently high in view of the in-refrigerator situation, the thermostat error and the operation irregularity. Accordingly, as for the ice ejecting operation, the thermostat operation temperature is set equal to or higher than the temperature at which the surfaces of the ice pieces are regarded as having been sufficiently melted.
Since, however, the thermostat operation temperature thus set heavily affects the temperature within the freezing compartment and the blowing operation to cool the inside of the refrigerator, it is necessary to strictly set the thermostat operation temperature depending on the type of the refrigerator. In the conventional electronically-operated automatic ice maker, there is a need to add a control board and a built-in program to the ice maker. This leads to a complicated configuration, an increased number of required components, and a corresponding price increase.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide an automatic ice maker arranged to reliably perform an ice ejecting operation without having to execute control using an electronic control board in spite of changes in the internal temperature of a freezing compartment and the influence of a blowing operation.
In accordance with a first preferred embodiment of the present invention, an automatic ice maker is installed within a freezing compartment and includes an ice tray arranged to hold water and make ice pieces; an ice ejecting mechanism arranged to eject the ice pieces made in the ice tray; an ice releasing heater arranged to melt surfaces of the ice pieces made in the ice tray; a thermostat arranged to detect a temperature of the ice tray and to operate at a specified temperature; an ice storage amount detecting mechanism arranged to detect a total amount of the ice pieces stored within an ice storage box; and a switch mechanism arranged to stop an operation of the ice releasing heater in conjunction with an operation of the ice ejecting mechanism.
Since the automatic ice maker includes the switch mechanism arranged to stop the operation of the ice releasing heater in conjunction with the operation of the ice ejecting mechanism, it is possible to stop the supply of an electric current to the heater regardless of the operation time point of the thermostat. Accordingly, there is no need to strictly set the thermostat operation temperature as is required in conventional automatic ice makers. It thereby becomes unnecessary to perform a task of preparing a built-in program required in an electronically-controlled system.
In accordance with a second preferred embodiment of the present invention, an automatic ice maker is installed within a freezing compartment and includes an ice tray arranged to hold water and make ice pieces; an ice ejecting mechanism arranged to eject the ice pieces made in the ice tray; an ice releasing heater arranged to melt surfaces of the ice pieces made in the ice tray; a thermostat arranged to detect a temperature of the ice tray and to operate at a specified temperature; an ice storage amount detecting mechanism arranged to detect a total amount of the ice pieces stored within an ice storage box; and a switch mechanism arranged to operate the ice releasing heater in conjunction with an operation of the ice ejecting mechanism until the surfaces of the ice pieces are regarded as having been melted.
Inasmuch as the automatic ice maker includes the switch mechanism arranged to continuously operate the ice releasing heater until the surfaces of the ice pieces are regarded as having been melted, it is not necessary to set the operation time point of the thermostat in conformity with the installation environment of the ice maker as is the case in conventional automatic ice makers. It becomes unnecessary to perform a task of preparing a built-in program required in an electronically-controlled system. In a preferred embodiment of the present invention, the heater is turned on by detecting the temperature with the thermostat. The heater is turned off when the operation state of the ice ejecting mechanism indicates that the surfaces of the ice pieces are regarded as having been melted. This provides an advantage in that the turning-off timing of the heater does not depend on the detection of the thermostat temperature easily affected by the surrounding environment.
The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an automatic ice maker in accordance with a first preferred embodiment of the present invention.

FIG. 2 is an electric wiring connection diagram of the automatic ice maker shown in FIG. 1.

FIG. 3 is an operation timing chart of the automatic ice maker shown in FIG. 1.

FIG. 4 is an operation flowchart of the automatic ice maker shown in FIG. 1.

FIG. 5 is an electric wiring connection diagram of an automatic ice maker in accordance with a second preferred embodiment of the present invention.

FIG. 6 is an operation timing chart of the automatic ice maker shown in FIG. 5.

FIG. 7 is an electric wiring connection diagram of an automatic ice maker in accordance with a third preferred embodiment of the present invention.

FIG. 8 is an operation timing chart of the automatic ice maker shown in FIG. 7.

FIG. 9 is an electric wiring connection diagram of a conventional automatic ice maker.

FIG. 10 is an operation timing chart of the automatic ice maker shown in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Preferred Embodiment

An automatic ice maker in accordance with a first preferred embodiment of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a perspective view of the automatic ice maker in accordance with the first preferred embodiment of the present invention. The automatic ice maker preferably includes an ice tray 1 including a plurality of ice making molds; an ice ejecting lever 2 arranged as an ice ejecting mechanism provided with a plurality of ice ejecting claws arranged to rake out ice pieces held in the ice making molds; a housing 3 arranged to accommodate a drive motor arranged to rotationally drive the ice ejecting lever 2, a cam mechanism, and various kinds of switches; an ice releasing heater arranged on the bottom surface of the ice tray 1; and a feeler arm 4 serving as an ice storage amount detector arranged to detect an ice storage amount of an ice storage tank arranged to store ejected ice pieces. A cam shaft included in the cam mechanism is rotated by the drive motor and the ice ejecting lever 2 is connected to the cam shaft.
FIG. 2 shows a preferred embodiment of the internal wiring connection arranged to control the operation of the automatic ice maker configured as above. A drive motor (M) 12 and a hold switch (SW) 14 (the normally-open (NO) terminal thereof) are connected to a power supply of, e.g., AC 115/230 V, through a temperature fuse 10. A heater 16 is connected in parallel to a serial circuit of the drive motor 12 and the hold switch 14 (the normally-open terminal thereof). A serial circuit of a water switch 18 and a water valve 20 and a serial circuit of a thermostat 22, a thermostat switch 24, and a feeler arm switch 26 (the normally-open terminal thereof) are connected between the normally-closed terminal and the normally-open terminal of the hold switch 14. The normally-closed terminal of the feeler arm switch 26 is connected to a common terminal of the hold switch 14. The water valve 20 is preferably installed in the refrigerator outside the automatic ice maker.
A cam is provided in the cam shaft rotated by the drive motor 12. Depending on the rotational position of the cam, the hold switch 14, the feeler arm switch 26, and the water switch 18 are switched and operated. The ice ejecting lever 2 is arranged to be rotated as the cam shaft rotates. The feeler arm 4 is swung in conjunction with the rotation of the cam shaft within a specified rotation angle range. The operations of the respective components caused by the rotation of the cam are as shown in the timing chart set forth in FIG. 3.
In the meantime, FIG. 9 is an electric wiring connection diagram of a conventional automatic ice maker including a twice rotation-type of ice ejecting lever. The conventional automatic ice maker is operated in accordance with the timing chart shown in FIG. 10.
Description will now be made on the operations of the conventional automatic ice maker shown in FIG. 9. The thermostat 22 is turned off in a state that water is held in an ice tray. Thus the drive motor 12 waits for ice making without making any rotation. In this state, a feeler arm 4 is kept in an ice detecting position.
If the water in the ice tray is frozen into ice pieces, the thermostat 22 detecting the ice making temperature is turned on. In response, the operation in an ice ejecting mode is started up. An electric current begins to be supplied to the drive motor 12 through the thermostat 22 and the feeler arm switch 26 (the normally-open terminal thereof). The cam shaft (not shown) operatively connected to the drive motor 12 begins to rotate. At the same time, the heater 16 is energized to heat the ice tray, thereby accelerating the release of the ice pieces. Immediately after the cam shaft begins to rotate, the hold switch 14 is operated (the normally-open terminal of the hold switch 14 is turned on). Thus, an electric current continues to be supplied to the drive motor 12 through the hold switch 14.
Thereafter, the feeler arm 4 is moved under the action of the cam shaft to a position where the feeler arm 4 does not hinder the ejection of the ice pieces (a position below the ice tray). The feeler arm switch 26 is operated by the cam mechanism (the normally-closed terminal of the feeler arm switch 26 is switched on).
Ice ejecting claws of an ice ejecting lever connected to the cam shaft make contact with the surfaces of the ice pieces and press the ice pieces in such a direction as to rake out the ice pieces. This state is maintained until the ice pieces become movable. If the surfaces of the ice pieces held in the ice tray begin to be melted by the heat of the heater 16 and if the ice pieces become movable, the ice ejecting lever pushes the ice pieces and the cam shaft continues to rotate, whereby the ice ejecting lever can rake out the ice pieces from the ice tray. Before and after this position, the normally-open terminal of the feeler arm switch 26 is switched on under the action of the cam surface of the cam shaft. The feeler arm 4 is swung into the ice detecting position (a position similar to the position of the preferred embodiment of the invention shown in FIG. 1).
If the cam shaft makes approximately one rotation, the water switch 18 (the normally-closed terminal thereof) is switched on under the action of the cam surface for a specified time. Since the thermostat 22 is kept turned on, no electric current flows through the water valve 20 to thereby eliminate the possibility that water will be supplied to the ice tray.
When the cam shaft is rotated 360 degrees, the hold switch 14 is switched to the normally-closed terminal and consequently turned off. Since the thermostat 22 is turned on at this time, the drive motor 12 is continuously supplied with an electric current through the thermostat 22 and is continuously rotated. Thereafter, the hold switch 14 is switched to continuously supply an electric current to the drive motor 12. The feeler arm 4 is swung into the original position and the normally-closed terminal of the feeler arm switch 26 is turned on.
The ice pieces raked out from the ice tray by the rotation of the cam shaft are discharged by the ice ejecting claws from the lateral surface of the ice tray and are stored in an ice storage tank existing below the ice tray. Thereafter, the normally-open terminal of the feeler arm switch 26 is turned on and the feeler arm 4 is swung into the ice detecting position. Even after the ice pieces are completely removed from the ice tray, the thermostat 22 is kept turned on. Accordingly, an electric current continues to be supplied to the heater 16. The ice tray is heated to a specified temperature. In response, the thermostat 22 detecting the temperature of the ice tray is turned off.
If the cam shaft is further rotated and if the normally-closed terminal of the water switch 18 is turned on, an electric current begins to be supplied to the water valve 20. This is because the thermostat 22 is kept turned off. The water valve 20 is opened for a specified time and, therefore, water is supplied to the ice tray.
If the supply of water is completed, the water switch 18 is switched to the normally-open terminal. Just thereafter, the hold switch 14 is switched to the normally-closed terminal and consequently turned off. The rotation of the drive motor 12 is stopped. Thus, the automatic ice maker comes into a standby state again.
In the conventional automatic ice maker, as described above, the ice ejecting mode and the water supplying mode are performed by rotating the cam shaft twice with the drive motor 12. With such conventional configuration, the thermostat 22 is turned on immediately after the ice pieces are made, and then the ice tray is heated by the heat of the heater 16. The ice pieces are raked out with the ice ejecting lever 2. The ice tray is further heated to a specified temperature. The heater 16 is continuously supplied with an electric current until the thermostat 22 is switched off.
In this configuration, it may be sometimes the case that, due to an in-refrigerator situation, thermostat error, or operation irregularity, the thermostat 22 will not be turned off even when the ice ejecting lever is rotated to a specified angle. In this case, the ice tray is continuously heated even after the ice pieces are released. Thus, electric power will be unnecessarily consumed.
In accordance with the present preferred embodiment shown in FIGS. 2 and 3, the thermostat switch 24, which is preferably a normally-closed switch of a heater de-energizing switch mechanism, is arranged between the thermostat 22 and the feeler arm switch 26. This makes it possible to perform the ice ejecting mode and the water supplying mode by one rotation of the cam shaft. In addition, it is possible to reliably perform the ice releasing operation while minimizing the supply of an electric current to the heater 16.
Specifically, referring to a flowchart shown in FIG. 4, water is supplied to the ice tray 1. Thereafter, the ice tray 1 is cooled to a specified temperature to start ice making. If a specified time is lapsed and if it is determined that the ice making is finished, the thermostat 22 is turned on and a closed circuit is defined by the normally-closed thermostat switch 24 and so forth. Thus, the drive motor 12 is rotated and the supply of an electric current to the heater 16 is started. Subsequently, the ice ejecting claws of the ice ejecting lever 2 connected to the cam shaft make contact with the surfaces of the ice pieces and press the ice pieces in such a direction so as to rake out the ice pieces. This state is maintained until the ice pieces become movable.
If the surfaces of the ice pieces held in the ice tray 1 begin to be melted by the heat of the heater 16 and if the ice pieces become movable, the ice ejecting lever 2 pushes the ice pieces and the cam shaft continues to rotate. After the ice ejecting lever 2 is rotated by a specified angle, e.g., about 90 degrees, the thermostat switch 24 is opened by a cam mechanism (not shown), thereby cutting off the current supply circuit of the heater 16. This stops the supply of an electric current to the heater 16. However, the drive motor 12 continues to rotate because an electric current is continuously supplied to the drive motor 12 through the hold switch 14.
The temperature of the ice tray 1 is continuously increased by the residual heat of the heater 16. After the temperature of the ice tray 1 reaches a predetermined level, the thermostat 22 is turned off and the connection thereof is cut off. The drive motor 12 continues to rotate thereafter. When the ice ejecting lever 2 reaches a specified position immediately ahead of the starting point, the water switch 18 is turned on and the connection to the water valve 20 is performed, thereby transmitting a water supply signal to the water valve 20. In response, an electric current to the water valve 20 is supplied for a specified time so that water is supplied to the ice tray 1. Thereafter, the water switch 18 is turned off again and the ice ejecting lever 2 is returned back to the starting point after making one rotation from the ice ejection startup time. In this manner, a series of operations comes to an end. The automatic ice maker stops its operation and waits in a standby state.

Second Preferred Embodiment

FIGS. 5 and 6 show an automatic ice maker in accordance with a second preferred embodiment of the present invention. FIG. 5 is a wiring connecting diagram of the automatic ice maker and FIG. 6 is a timing chart illustrating the operations of the automatic ice maker. In the present preferred embodiment, instead of including the heater deenergizing switch mechanism (the thermostat switch), the thermostat 22′ preferably includes a function of arbitrarily releasing a contact point.
If the ice making operation is finished and if the thermostat 22′ is turned on, the supply of an electric current to the drive motor 12 and the heater 16 is started to perform an ice ejecting mode. When the ice ejecting lever 2 is rotated by, e.g., about 90 degrees, a return switch of the thermostat 22′ is operated by a cam mechanism and the thermostat 22′ is forcibly turned off. Accordingly, it is possible for the cam mechanism to simultaneously perform the deenergizing of the thermostat 22′ and the deenergizing of the heater 16.

Third Preferred Embodiment

FIG. 7 shows the internal wiring connection arranged to control operation in an automatic ice maker in accordance with a third preferred embodiment of the present invention. A drive motor 12 and a hold switch 14 (the normally-open terminal thereof) are connected to a power supply of, e.g., AC 115/230 V, through a temperature fuse 10. A serial circuit of a heater 16 and a heater switch 28 (the normally-open terminal thereof) is connected in parallel to the drive motor 12 and the hold switch 14 (the normally-closed terminal thereof). A serial circuit of a water switch 18 and a water valve 20 and a serial circuit of a thermostat 22 and a feeler arm switch 26 (the normally-open terminal thereof) are connected between the normally-closed terminal and the normally-open terminal of the hold switch 14. The normally-closed terminal of the feeler arm switch 26 is connected to a common terminal of the hold switch 14. The normally-closed terminal of the heater switch 28 is connected to the normally-open terminal of the hold switch 14.
A cam is provided in the cam shaft rotated by the drive motor 12. Depending on the rotational position of the cam, the heater switch 28, the hold switch 14, the feeler arm switch 26, and the water switch 18 are switched and operated. The ice ejecting lever 2 is rotated as the cam shaft rotates. The feeler arm 4 is swung in conjunction with the rotation of the cam shaft within a specified rotation angle range. The operations of the respective components caused by the rotation of the cam are as shown in the timing chart set forth in FIG. 8.
The operations of the automatic ice maker of the present preferred embodiment will now be described with reference to FIGS. 7 and 8. After water is supplied to the ice tray 1, the ice tray 1 is cooled to a specified temperature to start ice making. If a specified time has lapsed and if the ice making is finished, the thermostat 22 detecting the ice making temperature is turned on. Thus, a closed circuit including the drive motor 12 is defined through the feeler arm switch 26 whose normally-open terminal is turned on, whereby the drive motor 12 starts a rotating operation.
Simultaneously with the start of the rotation operation of the drive motor 12 and in response to the turning-on of the thermostat 22, the supply of an electric current to the heater 16 is initiated through the heater switch 28 whose normally-open terminal is turned on. Thus the ice tray 1 is heated. The cam shaft is rotated in conjunction with the rotation of the drive motor 12. Under the action of the cam provided in the cam shaft, the hold switch 14 is switched from the normally-closed terminal to the normally-open terminal, so that the drive motor 12 is continuously supplied with an electric current.
Thereafter, the heater switch 28 is switched to the normally-closed terminal to be turned on under the action of the cam, so that the heater 16 is forcibly supplied with an electric current. Accordingly, the ice tray 1 is heated. The operation of turning on the normally-closed terminal of the heater switch 28 is set to be performed at the timing earlier than the timing at which the thermostat 22 is turned off by the detection of a predetermined ice-releasing temperature. Accordingly, even if the thermostat 22 is turned off next time, the drive motor 12 is continuously supplied with an electric current by the hold switch 14 and is continuously operated. The heater 16 is continuously supplied with an electric current through the normally-closed terminal side current flow path of the heater switch 28. Thus the ice tray 1 is continuously heated.
Thereafter, the ice ejecting claws of the ice ejecting lever 2 connected to the cam shaft make contact with the surfaces of the ice pieces held in the ice tray 1 and press the ice pieces in such a direction as to rake out the ice pieces. The ice ejecting claws continue to press the ice pieces until the surfaces of the ice pieces are melted and the ice pieces become movable. The drive motor 12 is kept stopped.
The temperature of the ice tray 1 is continuously increased by the heat of the heater 16. If the temperature of the ice tray 1 reaches a specified level, the thermostat 22 is turned off.
In this regard, the operating temperature of the thermostat 22 is set equal to an ice making temperature and an ice releasing temperature in the ice tray 1. In reality, the operating temperature of the thermostat 22 is largely affected by the error and operation irregularity of the thermostat 22 and the cold air circulation cycle and the blowing method used to cool the freezing compartment of a refrigerator mounted with this kind of automatic ice maker. During the cycle of accelerating the cold air circulation within the freezing compartment, it is sometimes difficult to release the ice pieces even when the temperature of the ice tray 1 reaches the specified temperature.
For that reason, the temperature at which the thermostat 22 is turned off is merely set equal to, e.g., the ice-releasable dish temperature. The rotation angle of the ice ejecting lever 2 at which the ice pieces are regarded as having been completely released is set. The operation time point at which the heater switch 28 is operated by the cam is set such that the heater switch 28 serving as a switch mechanism is switched over at the rotation angle.
As shown in FIG. 8, the supply of an electric current to the heater 16 is continuously performed even after the thermostat 22 is turned off. If the surfaces of the ice pieces held in the ice tray 1 begin to be melted, the ice pieces pressed by the ice ejecting claws of the ice ejecting lever 2 start to move. Thus, the cam shaft is allowed to rotate and the drive motor 12 is rotated subsequently. If the ice ejecting lever 2 is rotated into the rotation angle at which the ice pieces are regarded as having been completely released, the heater switch 28 is switched to the normally-open terminal by the cam of the cam shaft, thereby defining a closed circuit including the thermostat 22. Since the thermostat 22 is kept turned off at this time, the supply of an electric current to the heater 16 is stopped.
If the state in which the ice pieces are regarded as having been completely released becomes available as set forth above, the ice pieces are raked out from the ice tray 1 by the ice ejecting claws of the ice ejecting lever 2 pressing the ice pieces in a raking-out direction. The ice pieces are discharged from the lateral surface of the ice tray 1 and are stored in an ice storage tank arranged below the ice tray 1. Thereafter, the feeler arm switch 26 is switched to the normally-closed terminal and the feeler arm 4 is swung into the ice detecting position.
If the ice ejecting mode is finished in this manner, the water switch 18 is turned on by the operation of the cam. An electric current is supplied to the water valve 20 through the heater 16, the heater switch 28, and the water switch 18. The water valve 20 is opened for a specified time to supply water to the ice tray 1. Then, the water valve 20 is closed again. Subsequently, the ice ejecting lever 2 is returned back to the starting point after making one rotation. In this manner, a series of operations comes to an end. The automatic ice maker then waits in a standby state.
In the third preferred embodiment described above, the heater switch 28 is switched from the normally-closed terminal to the normally-open terminal at the timing when the ice ejecting lever 2 is rotated into the rotation angle at which the ice pieces are regarded as having been completely released. The electric current is continuously supplied to the heater 16 until the surfaces of the ice pieces are melted. This makes it possible to reliably perform the ice ejecting operation with the surfaces of the ice pieces kept in a melted state, without having to strictly set the operation temperature of the thermostat 22. Accordingly, it is possible to provide an effect of simplifying the setting of the thermostat 22 and the manufacture of the automatic ice maker.
Depending on the load state in the freezing compartment within which the automatic ice maker is installed, it is sometimes the case that the temperature of the ice tray 1 fails to reach the ice-releasable temperature even though the ice pieces are completely released by forcibly operating the heater 16 through the heater switch 28. In this case, the supply of an electric current to the heater 16 is controlled by the operation of the thermostat 22.
Specifically, as indicated by single-dot chain lines in FIG. 8, the supply of an electric current to the heater 16 is continuously performed through the thermostat 22 and the feeler arm switch 26 even when the heater switch 28 is switched to the normally-open terminal and turned on. This is because the thermostat 22 is kept turned on. Thereafter, if the temperature of the ice tray 1 is increased to a specified temperature by the heater 16, the thermostat 22 is turned off and the supply of an electric current to the heater 16 is terminated.
As shown in FIG. 8, the thermostat 22 is turned off after the heater switch 28 is switched from the normally-open terminal to the normally-closed terminal. Basically, the switching-off temperature of the thermostat 22 is set as low as possible (e.g., equal to or lower than about 0° C., i.e., an ice melting point). The heater 16 is configured to be turned off depending on the rotation angle of the ice ejecting lever 2. The timing at which the heater switch 28 is switched from the normally-closed terminal to the normally-open terminal is set in advance depending on the rotation angle of the ice ejecting lever 2 to an appropriate timing until the water supplying mode.
While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

Claims

1. An automatic ice maker installed within a freezing compartment, comprising:

an ice tray arranged to hold water and make ice pieces;

an ice ejecting mechanism arranged to eject the ice pieces made in the ice tray;

an ice releasing heater arranged to melt surfaces of the ice pieces made in the ice tray;

a thermostat arranged to detect a temperature of the ice tray and to operate at a specified temperature;

an ice storage amount detecting mechanism arranged to detect a total amount of the ice pieces stored within an ice storage box; and

a switch mechanism arranged to stop an operation of the ice releasing heater in conjunction with an operation of the ice ejecting mechanism.

2. The automatic ice maker of claim 1, wherein the switch mechanism includes a thermostat deenergizing mechanism arranged to stop the operation of the heater.

3. The automatic ice maker of claim 2, wherein the switch mechanism is provided in a serial relationship with the thermostat.

4. The automatic ice maker of claim 2, wherein the switch mechanism includes a return switch built in the thermostat.

5. The automatic ice maker of claim 1, further comprising:

a motor; and

a cam mechanism operated by the motor to actuate the ice ejecting mechanism and the ice storage amount detecting mechanism; wherein

the switch mechanism is operated by the cam mechanism.

6. An automatic ice maker installed within a freezing compartment, comprising:

an ice tray arranged to hold water and to make ice pieces;

a switch mechanism arranged to operate the ice releasing heater in conjunction with an operation of the ice ejecting mechanism until the surfaces of the ice pieces are regarded as having been melted.

7. The automatic ice maker of claim 6, wherein the switch mechanism is provided in a serial relationship with the thermostat and is configured to switch a current supply path of the heater between a current supply circuit including the thermostat and a circuit through which an electric current bypassing the current supply circuit is supplied to the heater regardless of the operation of the thermostat.

8. The automatic ice maker of claim 6, further comprising:

a motor; and

the switch mechanism is operated by the cam mechanism.

9. The automatic ice maker of claim 8, wherein

the ice ejecting mechanism includes an ice ejecting lever including ice ejecting claws arranged to rake out the ice pieces from the ice tray in conjunction with rotation of the motor;

the motor is configured to start operation when the thermostat is turned on by detecting an ice making temperature; and

the ice ejecting claws of the ice ejecting lever press against the surfaces of the ice pieces held in the ice tray until the thermostat is turned off at a specified temperature after the ice tray is heated by the heater.