US3714794A - Drive motor-defrost timer for refrigerator - Google Patents

Abstract

A TIMER FOR CONTROLLING THE DEFROST OPERATION OF A REFRIGERATION APPARATUS. THE REFRIGERATION APPARATUS INCLUDES AN ICE BODY MAKER HAVING A DRIVE MOTOR. THE ICE MAKER DRIVE MOTOR IS UTILIZED ALSO TO DRIVE THE DEFROST TIMER. THE CONTROL PERMITS THE ICE MAKER MOTOR TO OPERATE CONTINUOUSLY WHILE DISCONTINUING ICE BODY PRODUCTION SUCH AS WHEN THE ICE HARVESTING CONTAINER IS FULL.

D R A W I N G

Description

6, 1973 w. J. LINSTROMBERG ETAL 3,714,794

DRIVE MOTOR-DEFROST TIMER FOR REFRIGERATOR Original Filed June 1'7, 1970 2 Sheets-Sheet l IIIIHIIH WILL/AM J. Lmsreomatea DUANE C. NICHOLS BY j W, dli ."fl CMI'TORNEY INVENTOR Feb. 6, 1973 w. J. LINSTROMBERG ETAL 3,714,794

DRIVE MOTORDEFROST TIMER FOR REFRIGERATOR Original Filed June 17, 1970 2 Sheets-Sheet 2 CABINET THERMOSTAT COMPRESSOR OEFROsT HEATER 1 ml H DEFROST SWlrcu ICE MAKER Bl-METAL V/LL/AM J. lnvsreowzea Dun/v5 C. Mums ATTORNEY United States Patent O 3,714,794 DRIVE MOTOR-DEFROST TIMER FOR REFRIGERATOR William J. Linstromberg and Duane C. Nichols, Evansville, Ind., assignors to Whirlpool Corporation Continuation of abandoned application Ser. No. 46,921, June 17, 1970. This application Feb. 4, 1972, Ser.

Int. Cl. F25c 1/10 U.S. Cl. 62-137 14 Claims ABSTRACT OF THE DISCLOSURE CROSS-REFERENCE TO RELATED APPLICATION This application comprises a continuation of copending application Ser. No. 46,921, filed June 17, 1970, now abandoned, for Drive Motor-Defrost Timer for Refrigerator, and owned by the assignee hereof.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to refrigeration apparatus and in particular to means for timing a defrost cycle in such refrigeration apparatus.

Description of the prior art In conventional refrigeration apparatus such as frostless type refrigerators provided with means for making and harvesting ice bodies, a synchronous timing motor is provided to control the ice body forming and harvesting operations. conventionally additional means are provided for cyclically defrosting the refrigeration apparatus. Such defrost control means conventionally include a second timer motor. Such provision of both the ice body maker motor and separate defrost timer motor is relatively ex pensive.

Another disadvantage of the conventional refrigeration apparatus is the provision of the defrost timer motor in the apparatus space which may be at a relatively high temperature. Thus, it has been found that the defrost timer motor presents a maintenance problem due to the adverse efiects of such high temperature environmental conditions.

SUMMARY OF THE INVENTION The present invention comprehends an improved refrigeration apparatus wherein a single drive motor is utilized for controlling the ice body making and harvesting operations as well as the defrost timing operation. The control is arranged to permit the drive motor to operate continuously. Means are provided for intermittently 3,714,794 Patented Feb. 6, 1973 discontinuing ice body production as an incident of a full condition in the harvesting receptacle.

The invention comprehends the provision of means for interrupting the operation of the drive motor in the event that the temperature within the freezer compartment rises above a preset temperature, such as 20 F., at which time it is desirable to prevent further operation of the ice body maker.

The invention further comprehends providing means to maintain the operation of the drive motor during the defrost cycle notwithstanding a rise in the temperature sensed by the ice maker limit thermostat at such time.

More specifically, the present invention is directed to a control means for use in an apparatus having an ice body maker including mechanism for cyclically controlling formation and harvesting of ice bodies, a continuously operated drive motor driving the mechanism, and means driven by the continuously operated drive motor for causing defrosting of the apparatus.

A thermostat control may be utilized in lieu of the timer motor for controlling the operation of the ice making and harvesting mechanism. This control may be arranged similarly to the timer motor control discussed above to provide the desired disconnection of the ice body making and harvesting means under the preselected conditions discussed above while permitting the timer motor to continue to control the defrost operation.

The control may include a suitable clutch to effectively preclude stalling of the ice making mechanism from interrupting the defiost timing operation.

The control is extremely simple and economical of construction while yet providing the highly desirable features discussed above.

BRIEF DESCRIPTION OF THE DRAWING Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

'FIG. 1 is a fragmentary perspective View of a refrigeration apparatus incorporating the invention;

FIG. 2 is a perspective view of an ice body maker suitable for use in the invention;

FIG. 3 is a fragmentary elevational view of the control for the ice body maker of FIG. 2;

FIG. 4 is a fragmentary exploded perspective view of a refrigeration apparatus control mechanism embodying the invention; and

FIG. 5 is a schematic electrical wiring diagram thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the exemplary embodiment of the invention as disclosed in the drawing, a refrigeration apparatus generally designated 1 is shown to comprise a freezer section 2 and a fresh food storage section 3. The apparatus further includes a compressor 4, a condenser 5, a capillary 6 and evaporator 7. Located within freezer section 2 is an ice body maker generally designated 8. The refrigeration apparatus control generally designated 10 is shown to comprise a drive motor 11 arranged to be operated continuously. The drive motor is mounted within a housing 12 which is conventionally disposed in the freezer section 2 of the refrigeration apparatus. Housing 12 may include an auxiliary housing 13 adapted to house a drive gear assembly generally designated 14. Assembly 14 includes a drive pinion 15 for driving the ice body maker harvesting means. One excellent example of an ice body making and harvesting apparatus adapted for use with such a controllt) is shown in Frohbieter U.S. Letters Patent No. 3,382,682 owned by the assignee hereof. The drive assembly 14 is arranged to operate a switch device 16 mounted within housing 12 for controlling the defrost operation. The drive assembly 14 is driven from motor 11 by a drive pinion 17 which is directly connected to the motor through a gear reduction unit 18 which illustratively provides a 1 r.p.m. drive of pinion 17. A slip clutch 19 is provided between pinion 1'7 and pinion 15 for impositively driving pinion 15 from pinion 17 permitting stalling of the ice body making and harvesting apparatus without affecting the continuous drive of pinion 17. Clutch 19 may comprise any suitable clutch means. An example of one suitable clutch is shown in the copending application of William Linstromberg, Ser. No. 47,518 entitled Clutch for Domestic Ice Maker with Defrost Timer, filed on June 18, 1970.

Pinion 17 projects through a suitable opening 20 in the front face 21 of housing 12 to engage a gear 22 having a small pinion 23 fixedly associated therewith. Pinion 23 in turn drives a reduction gear 24. Pinion 23 is journaled in a suitable hole 25 in housing front face 21 and gear 24 is journaled on a shaft 26 in turn journaled in a hole 27 in housing front face 21.

A cam 28 is fixed to shaft 26 and includes a plurality of spring fingers 29 adapted to releasably engage slots 30 in gear 24 to provide a clutch connection between gear 24 and cam 28. A pinion 31 is coaxially mounted on shaft 26 for rotational movement with cam 28 and in driving association with a gear 32 mounted on a shaft 33 journaled in a hole 34 in housing front face 21. A cam 35 is fixedly mounted on shaft 33 rearwardly of gear 32 and a slotted head 36 is provided on the forward end of shaft 33 for engagement by a screwdriver through an opening 37 in the front face 38 of auxiliary housing 13.

Auxiliary housing front face 38 is further provided with a pair of holes 39 through which may be passed suitable screws 40 for threaded engagement with a complementary pair of threaded holes 41 in front face 21 of housing 12 for securing the auxiliary housing in place on the front of housing 12. Front face 38 is further provided with additional journal holes 42, 43 and 44. Gear 22 is provided with a forwardly projecting stub shaft 45 journaled in auxiliary journal hole 42 and pinion 31 is provided with a forwardly projecting stub shaft 46 journaled in auxiliary journal hole 43.

A cam follower generally designated 47 includes a finger 48 adapted to ride on outer surface 49 of cam 28 to drop into a notch 56 at preselected intervals. Finger 48 further includes a shoulder portion 51 which is adapted to ride on outer surface 52 of cam 35 and drop into a notch 53 therein at preselected intervals. The follower 47 includes a forwardly projecting stub shaft 54 journaled in auxiliary journal hole 44 and a rearwardly projecting stub shaft 55 journaled in a hole 56 in front face 21 of housing 12 for swingably mounting the follower finger 48. An actuator arm portion 57 of cam follower 47 projects rearwardly through a hole 58in housing front face 21 to suitably engage actuating portions 59 of switch means 16 as a function of the movement of cam follower finger 48.

In operation, drive motor 11 drives the ice making and harvesting mechanism to provide an automatic cyclical forming and harvesting of ice bodies, such as shown in the above-identified Frohbieter patent. Motor 11 is energized continuously so as to drive pinion 17 correspondingly continuously at a speed illustratively of 1 r.p.m. The operation of the ice maker may proceed as in the conventional manner wherein it is stopped at times, such as when the ice collecting and storing bin 60 thereof is full.

Pinion 17 drives the reduction gear 24 through gear 22 and pinion 23 so as to concurrently drive cam 28 and pinion 31. Pinion 31 drives gear 32 illustratively at a speed of approximately 2 revolutions per day. Approximately every 12 hours shoulder 51 on cam follower finger 48 becomes aligned with notch 53 of cam 35 permitting finger 48 to drop into notch 50 of cam 28 when notch 50 becomes aligned with finger 48, this in turn permits actuator 57 to rotate and thereby operate switch means 16.

Thus, the length of cam notch 50 provides an accurate preselected time of defrost corresponding to the length of the notch in accordance with the rotational speed thereof effected by the reduction gearing mechanism. Cam notch 53 schedules the operation of the defrost cycle illustratively twice daily. If desired, however, suitable gears and pinions may be provided to eifect the defrost operation at other intervals such as once every 24 hours where the humidity conditions are known to be relatively low, or alternatively every 8 hours where the humidity conditions are known to be relatively high. Alternatively, the cam 35 may be provided with a different notch arrangement from that shown in FIG. 1 to provide a different preselected defrost time.

As the timer motor 11 is mounted in the control 10 which is conventionally mounted in a refrigerated compartment such as freezer section 2 of the apparatus, the timer motor is operated under relatively low temperature environmental conditions thereby permitting the use of a low cost motor while yet effectively minimizing maintenance requirements.

As shown in FIG. 5, the timer motor 11 may be connected through a single-pole, double-throw bimetallic thermostat switch 61. Switch 51 is connected in series with a single-pole, single-throw valve switch 62 and a water fill solenoid valve 63. The compressor motor 4 of the refrigeration apparatus may be connected in series with a single-pole, single-throw cabinet thermostat switch 65 and a single-pole, double-throw defrost switch 66 between power supply leads L1 and L2. The defrost heater 67 may be connected in series with a bimetallic singlepole, single-throw defrost switch 68 connected to each of a first fixed contact 66a of switch 66 and a first fixed contact 61a of switch 61. Cabinet thermostat switch 65 is connected to a second fixed contact 661; of switch 66 and moving contact 660 thereof is connected first to a second fixed contact 611) of switch 61 which in turn is connected to power supply lead L1. Moving contact 610 of switch 61 is connected to timing motor 11 and valve switch 62 as shown in FIG. 5.

Thus, timing motor 11 runs continuously as long as switch 61 is in the position shown in FIG. 5 with the moving contact 610 engaging fixed contact 61b thereof. Switch 61 is arranged to be in this position at all times other than when the freezer temperature is above a preselected temperature such as 20 F. It has been found that such discontinuance of the operation of timer motor 11 has substantially no efiect on the required defrost cycling time. Defrost switch 66 may comprise one portion of switch means 16, as shown in FIG. 1, and is arranged to have its moving contact 660 thrown into engagement with fixed contact 66a to initiate the defrost operation. As fixed contact 61a of switch 61 is connected to fixed contact 66a of defrost switch 66, timing motor 11 is energized through switch 66 in the event that the ice maker switch 61 is operated to throw its moving contact 61:: into engagement with fixed contact 61a. Thus, the ice maker thermostat switch is effectively bypassed during the defrost cycle to maintain the desired continuous operation of timing motor 11 notwithstanding the opening of switch 61b-61c such as may result from the heat of the defrosting operation.

In order to provide for discontinuing the production of ice bodies when storage bin 69 becomes full, a switch 70 in series with water valve switch 62 and solenoid valve 63 may be provided. The switch 70 may be actuated by suitable mechanism (not shown) in response to a full condition of the storage bin. Two suitable mechanisms are shown in the copending application of William Linstromberg, Ser. No. 47,519, entitled Water Pill Shut-Off Control for Domestic Ice Maker and filed June 18, 1970. Opening of the switch 70 is effective to preclude energization of solenoid valve 63 and the ice maker is thus starved of water. With the ice maker starved of water, the mechanism can continue to operate without over producing ice bodies and the defrost timing function can continue without interruption.

If operation of the ice maker mechanism is undesirable, when the storage bin is full, a mechanical disabling mechanism can be used. Such a mechanism is shown and described in the copending application of Duane Nichols, Ser. No. 46,920, entitled Mechanical Bin Level Sensing Control for Domestic Ice Maker" and filed concurrently herewith. FIG. 3 shows such a mechanism wherein a pin 71 connects a drive shaft 72 to a drive gear 73 on a periodic timed basis through a series of cams. The drive gear 73 is continuously driven by pinion 15 of motor 11. When ice storage bin 60 is full as sensed by a sensing arm 74, a latch 75 is released to lock pin 71 in a disconnected position relative to drive gear 73. Thus the ice maker is effectively disconnected from its drive means and ice production is discontinued while continuous operation of motor 11 continues to time the defrost operation of the refrigeration apparatus.

To permit facilitated testing of control 10, such as in serving thereof, movement of cam 35 may be effected by suitably engaging a screwdriver in slotted head 36 to turn gear 32 and cam 35 which in turn drives pinion 31 to rotate cam 28. Spring fingers 29 move outwardly from slots 30 under such conditions to provide a one-way clutch arrangement whereby operation of cam follower 47 may be effected, such as for testing purposes.

The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A refrigeration apparatus comprising: ice maker means constructed to be operated by a mechanical driving force for cyclically making and mechanically harvesting ice bodies; means for causing defrosting of said refrigeration apparatus; an electrically operated motor; power transmitting means connecting said motor to said ice maker means for providing from the motor the mechanical force for operating the ice maker means; and timing means driven by said motor for timing the operation of said defrosting means.

2. The refrigeration apparatus of claim 1 wherein said apparatus includes means defining a chamber, means for maintaining said chamber at freezing temperature, and means mounting said electrically operated motor in said chamber.

3. The refrigeration apparatus of claim 1 wherein said motor and power transmission means define a drive means and said apparatus further includes safety means associated with said drive means permitting continued operation of said drive means to drive said timing means notwithstanding a stalling of said ice maker means.

4. The refrigeration apparatus of claim 1 wherein said ice maker means includes thermostat means for controlling the cyclical operation of said ice maker means.

5. The refrigeration apparatus of claim 1 wherein said ice maker means includes time-responsive means for controlling the cyclical operation of said ice maker.

6. The refrigeration apparatus of claim 1 including speed reducing means connected between said electrically force for cyclically making and mechanically harvesting ice bodies; means for causing defrosting of said refrigeration apparatus; and a single electrically operated motor driving an output drive for providing the mechanical force for operating the ice maker means, and timing the operation of said defrosting means, said ice maker means including selectively connectable means for intermittently causing operation of said ice maker means by said drive motor.

8. The refrigeration apparatus of claim 1 wherein said ice maker means includes ice storage means and further includes means for preventing operation of the ice maker means by the drive motor when the ice storage means is full while permitting continued operation of the drive motor.

9. In a refrigeration apparatus including refrigeration means for providing a freezing condition in said refrigeration apparatus, mechanically operable ice maker means for cyclically forming and harvesting ice bodies, means for defrosting said refrigeration apparatus, electrically operated drive means for providing the mechanical force for operating said ice maker means, and timing means for causing operation of said defrosting means at periodic intervals,

means for driving said timing means from said drive means, and

control means for preventing operation of the electrically operated drive means in the event the temperature of said refrigeration means rises above a preselected temperature.

10. In a refrigeration apparatus including refrigeration means for providing a freezing condition in said refrigeration apparatus, mechanically operable ice maker means for cyclically forming and harvesting ice bodies, means for defrosting said refrigeration apparatus, electrically operated drive means for providing the mechanical force for operating said ice maker means, and timing means for causing operation of said defrosting means at periodic intervals,

means for driving said timing means from said drive means,

control means for preventing operation of the electrically operated drive means in the event the tempera ture of said refrigeration means rises above a preselected temperature, and

means for bypassing said control means during a defrosting operation to maintain operation of said drive means during said defrosting operation notwithstanding a rise of temperature of said refrigeration means to above said preselected temperature.

11. In a refrigeration apparatus including mechanically operable ice maker mechanism for cyclically forming and harvesting ice bodies, mechanism for defrosting said refrigeration apparatus, electrically operated drive means for providing the mechanical force for operating said ice maker means, and timing means for causing operation of said defrosting means at periodic intervals,

means for driving said timing means for said drive means, and

safety clutch means associated with said drive means permitting continued operation of said drive means notwithstanding a stalling of one of said mechanisms.

12. The refrigeration apparatus of claim 11 wherein said safety clutch means comprises a slip clutch.

13. A refrigeration apparatus comprising:

drivable ice maker means for cyclically making and harvesting ice bodies;

means for causing defrosting of said refrigeration apparatus;

a drive motor;

means for causing said drive motor to time said defrosting means and intermittently drive said ice maker means; and

means for selectively manually driving said defrosting means to test the control of the defrosting operation without driving said ice maker means.

14. The refrigeration apparatus of claim 1 wherein said defrosting means includes cam means rotated by said motor, switch means for controlling the defrost operation, and a cam follower coacting with said cam means to cyclically operate said switch means for a preselected period of time and at preselected spaced intervals as a function of the speed of rotation and the configuration of said cam means.

References Cited UNITED STATES PATENTS 3,541,806 11/1970 Jacobs 62-233 5 2,569,113 9/1951 Munshower 62-233 3,449,919 6/1969 Fox 62--233 X WILLIAM E. WAYNER, Primary Examiner US. Cl. X.R. 10 62233

Images