US3312080A

US3312080A - Household refrigerator including automatic icemaker and control means therefor

Info

Publication number: US3312080A
Application number: US529863A
Authority: US
Inventors: John A Dahlgren
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1966-02-24
Filing date: 1966-02-24
Publication date: 1967-04-04
Anticipated expiration: 1984-04-04

Description

April 4, 1967 A. DAHLGREN 3,312,080

- J. HOUSEHOLD REFRIGERATOR INCLUDING AUTOMATIC ICEMAKER AND CONTROL MEANS THEREFOR Filed Feb. 24, 1966 2 Sheets-Sheet 1 F'IG.2. v

INVENTOR. TOHN A. DAHLGREk) H\S ATTORNEY April 4, 1967 J. A. DAHLGREN 3,312,080

HOUSEHOLD REFRIGERATOR INCLUDING AUTOMATIC ICEMAKER AND CONTROL MEANS THEREFOR Filed Feb. 24, 1966 2 Sheets-Sheet 2 & l

FTC-3.3

INVENTOR.

J'OHN A. DAHLGREN ws ATTORNEY United States Patent Office 3,312,080 Patented Apr. 4, 1967 3,312,080 HOUSEHOLD REFRIGERATOR INCLUDING AU- TOMATIC ICEMAKER AND CONTROL MEANS THEREFOR John A. Dahlgren, Louisville, Ky, assignor to General Electric Company, a corporation of New York Filed Feb. 24, 1966, Ser. No. 529,863 1 Claim. ((31. 62]l55) The present invention relates to a household refrigerator including a freezer compartment containing an automatic icemaker and is more particularly concerned with improved control means for controlling the operation of both the refrigeration system component of the refrigerator and the icemaker.

The evaporator for cooling the freezer compartment of a household refrigerator normally operates at below freezing temperatures. In order to maintain the desired efi'i' ciency and operating capacity of such evaporators, it IS necessary to remove periodically from the evaporator surfaces the frost layer which collects thereon by Warming the evaporator to defrost temperatures either by means of hot refrigerant gas or electrical resistance heating. To effect the periodic defrosting of the evaporator, such refrigerators usually include control means for automatically interrupting the normal operation of the refrigerator and effecting a defrost operation.

A number of refrigerators of this type also include automatic icemakers adapted to operate in the freezer compartment. Automatic icemakers of the type in which ice pieces are removed or harvested from the ice mold by effecting a movement of the mold have heretofore included controls adapted to terminate a freezing cycle and initiate an ejection or harvesting cycle in response to a predetermined below freezing mold temperature. Accurate control has required the use of a temperature sensing means fixed to the mold so as not to be affected by compartment temperatures and hence including flexible leads subjected to flexing during each harvesting cycle.

The primary object of the present invention is to provide a household refrigerator including an automatic icemaker of the movable mold type and improved control means for the icemaker incorporated into and forming a part of the refrigerator control means.

A more specific object of the invention is to provide in a household refrigerator-automatic icemaker combination lower cost control means which does not require a flexible temperature sensing device associated with the icemaker mold.

A more specific object of the invention is to provide an auto defrost household refrigerator including an automatic icemaker in which both the operation of the evaporator defrost means and the icemaker are controlled by a simple timer controlled circuitry.

Further objects and advantages of the invention will become apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claim annexed to and forming a part of this specification.

In carrying out the objects of the present invention, there is provided a household refrigerator comprising, in combination, a freezer compartment, a refrigeration system including an evaporator normally operating at belowfreezing temperatures for serving the compartment, defrost means for the evaporator, an automatic icemaker within the compartment and including a movable ice mold from which the ice pieces are mechanically discharged or harvested and improved means for controlling the operation of the refrigeration system, the defrosting means and the icemaker. The improved control circuitry comprises a timer switch means including a timer motor which is energized whenever the compressor is operating to maintain the evaporator and freezer compartment at belowfreezing temperatures and timer operated switch means for periodically initiating both a defrost cycle of operation and a harvesting cycle of operation of the icemaker.

For a better understanding of the invention, reference may be had to the accompanying drawing in which:

FIGURE 1 is a front elevational view of the freezer compartment portion of a household refrigerator having positioned therein an automatic icemaker of the mechanical harvesting type;

FIGURE 2 is a vertical view, partly in section, of the icemaker; and

FIGURE 3 is a schematic diagram of an auto defrosting refrigeration system and control circuitry embodying the present invention.

While the invention will be described with reference to a household refrigerator including a specific auto defrost refrigerating system and a specific automatic icemaker of a movable mold type, it will be understood that it is not limited thereto. In other words, the invention is applicable to any combination of a household refrigerator including either electrical or hot refrigerant gas means for periodically defrosting the evaporator component thereof and any automatic icemaker of the type in which ice pieces are mechanically harvested by movement of an ice mold.

With reference to FIGURE 1 of the drawing there is shown a household refrigerator including a fresh food storage compartment 1 and a freezer compartment 2 both of which are maintained within their desired operating temperature ranges by air circulated over an evaporator 3 (FIGURE 3) contained within a housing 3a positioned adjacent the rear wall of the freezer compartment 2. The general construction of the refrigerator is the same as that shown and described in Patent 3,050,955, Solley, Jr., et al., issued Aug. 28, 1962, and reference is hereby made to that patent for further details concerning the overall construction of the refrigerator.

A11 icemaker 4 of the type having a movable mold for mechanically harvesting ice pieces is provided in the freezer compartment 2. Preferably the icemaker is positioned in front of the air outlet 5 so that the air which is circulated over and cooled to sub-freezing temperatures by the evaporator 3 is directed onto the icemaker.

The icemaker 4- shown in greater detail in FIGURE 2 of the drawing is merely representative of the class of icemakers including a mold which is moved for mechanical release and discharge of ice pieces formed therein. Except for the control concepts of the present invention, this icemaker has the same general construction and mode of operation as that shown and described in Patent 3,126,714, Zuercher, Jr., issued Mar. 1, 1964, and reference is hereby made to the Zuercher patent for a more detailed description thereof. Briefly described, this icemaker comprises an annular ice mold 6 including a plurality of generally pie-shaped cavities 7 in which water supplied to the mold through a supply line 8 is frozen into ice. The mold 6 is mounted on the upper end of a shaft 9 driven by a motor 1%, energization of the motor 10 causing the mold 6 to rotate about its axis whereby ice pieces 11 formed therein are discharged centrifugally from the mold for storage in a storage bin 12 positioned below the icemaker.

More specifically, the ice mold is slidably supported on the shaft 9 by a spring 14 which biases the mold 6 to an upper position when it is empty but which :allows the mold to move to a lower position when filled with water or ice. The flow of water to the mold through the supply line 8 is controlled by means of a switch 15 adapted to stop the flow of water when the mold is in its lower position. Means for stopping the automatic operation of the icemaker when the bin 12 is filled with ice comprises a cup-shaped member 16 mounted on the lower end of the shaft 9 and adapted to be raised by pivot levers 17 to an upper position during each harvesting cycle. A bin control switch 1.; operated by the sensing cup 16 stops operation of the icemaker whenever the member 16 remains supported in its upper position by the accumulation of ice pieces in the receptacle 12.

As described in the aforementioned Zuercher patent, the usual means for terminating the freezing cycle of operation and initiating the ejection or harvesting cycle of operation is to provide a thermostat switch means for sensing the temperature of the ice mold and initiating a harvesting cycle when the temperature of the mold is indicative of complete freezing of the water contained therein.

In accordance with the present invention, there is provided control circuitry for controlling the operation of the icemaker whereby a harvesting cycle is initiated as a function of time employing the same timing means as that used for periodically initiating a defrost cycle for the purpose of defrosting the evaporator 3. This control circuitry and a refrigeration system suitable for the practice of the present invention is shown in FIGURE 3 of the drawing. The refrigeration system includes in closed, series connection a motor compressor unit 21, a condenser 22, a flow restricting capillary 23 and the evaporator 3. The evaporator 3 normally operates at belowfreezing temperatures. For the purpose of periodically warming the evaporator to defrost temperatures, there is provided an auxiliary circuit for conducting hot refrigerant gas from the compressor 21 into heat exchange relationship with the evaporator 3. This auxiliary refrigerant fioW circuit includes a conduit 24 containing a normally closed solenoid valve 25 and defrost portion 26 in heat exchange relationship with the evaporator 3 and connected by a flow restrictor 27 to the compressor suction line 23 between the evaporator and the compressor. When the solenoid valve 25 is opened hot compressed refrigerant from the compressor flows through the defrost section 26 to warm the evaporator to defrost temperatures.

During normal or refrigerating operation, energization of the compressor 21 is controlled by a thermostat 30 which is directly or indirectly responsive to the temperatures maintained in the freezer compartment 2 and which includes a switch 31 adapted to close and connect the compressor across

supply lines

33, 34 when the compartment temperatures reach a predetermined high but belowfreezing point and to open when the compartment temperatures reach a predetermined low point. A timer 37 includes a timer motor 38 connected in parallel with the compressor 21 across the

supply lines

33 and 34 so that it is energized whenever the compressor is energized by closing of the switch 31. The timer provides means for effecting a defrost cycle of operation after a predetermined total compressor running time and also to effect a harvesting cycle of the icemaker after a predetermined compressor running time. This control of the icemaker 4 is made possible by the fact that the time required for freezing water contained in the mold 6 is directly related to the compressor running time.

To this'end, the timer 37 includes a defrost control switch 41 operated by the timer motor 38 and adapted after a predetermined compressor running time to connect the solenoid valve 25 across the

supply lines

33 and 34 through the compressor control switch 31 so that upon the next call for operation of the compressor, hot compressed refrigerant will flow through the defrost portion 26 for a time sufficient to warm the evaporator 3 to defrosting temperatures. After a predetermined defrost cycle of operation, switch 41 opens to de-energize and close the solenoid valve 25 whereby the refrigeration system is returned to normal refrigerating operation. A timer operated holding switch 42 provides a holding t circuit for connecting the timer motor 38 directly across the

supply lines

33 and 34 to assure continued operation of the timer motor 38 in the event that switch 31 opens during the defrost cycle.

For the purpose of providing timed operation of the icemaker drive motor 10 to initiate a harvesting cycle of operation of the icemaker, there is provided an icemaker control circuit including a safety switch 45, and a timer switch 46 driven by the timer motor 38. The safety switch 45 is designed to close only when the compartment 2 is at below freezing temperatures and may be part of the thermostat control 30. The timer switch 46 is a two position switch with the switch arm 47 normally engaging the contact 48. At predetermined intervals of a length sufi'icient to assure freezing of the water contained within the mold 6, the timer motor 38 moves switch arm 47 into engagement with contact 49 thereby connecting the icemaker drive motor 10 across the

supply lines

33 and 34 through the mold weighing switch 15 including a switch arm 50 which engages a first contact 51 when the mold is filled with water or ice. Energization of the drive motor 10 causes rotation of the mold 6 to discharge ice pieces therefrom whereupon the switch arm 50 of the mold switch 15 moves out of engagement with contact 50 and into engagement with contact 52. This results in de-energization of the drive motor 10 and conditions the mold switch 15 for energization of a solenoid water supply valve 55 controlling the flow of water through the mold supply line 8 upon subsequent movement of the switch arm 47 forming part of the timer switch 46 into engagement with the contact 48.

Assuming that the bin switch 18 is closed indicating that the bin 12 is not filled with ice, the solenoid valve 55 will be energized and opened by completion of the circuit across the

supply lines

33 and 34 including the safety switch 45, contact 43 of the timer switch 46, the closed bin switch 18 and the contact 52 of mold weighing switch 15. The solenoid valve 55 will remain energized and water supplied to the mold until the switch arm 51) of switch 15 is moved out of engagement with the contact 52 and into engagement with the contact 51 by the added Weight of the water charge. The holding switch 42 assures completion of the harvesting and water refilling cycle of operation regardless of the position of the thermal control switch means 31.

For the above description it will be seen that there has been provided a household refrigerator including an automatic ice maker and an automatic evaportaor defrost means both of which are operated by and under the control of a single timer means. The control circuitry is so designed as to provide both periodic defrosting of the evaporator component of the refrigeration system and an automatic ice harvesting cycle of operation of the icemaker.

While the invention has been described with reference to a specific auto defrost refrigeration system and a spe cific automatic ice maker it will be understood that it is not limited thereto and is intended by the appended claim to cover all such modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

A household refrigerator comprising in combination:

a freezer compartment;

a refrigerating system including a compressor and an evaporator normally operating at below-freezing temperatures for maintaining said compartment at below-freezing temperatures;

defrost means for periodically warming said evaporator to defrosting temperatures;

an automatic icemaker disposed in said compartment including a movable ice mold in said compartment and means including a drive motor for moving said mold to eject ice therefrom;

and control means for controlling the operation of said compressor, defrost means and icemaker comprising;

timer including a timer motor and a plurality of timer switches operated by said timer motor,

a first circuit including thermal switch means operated by thermal sensing means responsive to the temperature of said compartment for periodically operating said compressor to maintain said evaporator and said compartment at below-freezing temperatures and for energizing said timer motor whenever said compressor is operated,

a second circuit including a timer operated switch for operating said defrost means to defrost said evaporator after a predetermined total compressor operating time,

and an icemaker control circuit including a timer operated switch for periodically energizing said drive motor to operate said icemaker through a harvesting cycle and a safety circuit including a safety switch operated by said thermal sensing means for preventing energization of said drive motor unless said compartment is at a below-freezing temperature.

References Cited by the Examiner UNITED STATES PATENTS ROBERT A. OLEARY, Primary Examiner. W. E, WAYNER, Assistant Examiner.