Clutch For Domestic Ice Maker With Defrost Timer Drive Motor

Abstract

A control means for use in a refrigeration apparatus permitting the use of a single motor for driving both a defrost control mechanism and an ice maker control mechanism. The control means includes a slip clutch permitting the motor to continue to drive the defrost timer mechanism notwithstanding a stoppage of the ice maker mechanism, such as by jamming thereof.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to refrigeration apparatus and in particular to control means for use therein utilizing a single motor both as a defrost control timer and an ice maker drive means.

2. 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 expensive.

It has been proposed to provide a single drive motor for controlling both the ice body making and harvesting operation and the defrost timing operation. A problem arises, however, in the use of such a single drive motor in that at times the ice making mechanism may become jammed such as by an ice body becoming lodged between parts of the mechanism. Such a jammed condition would undesirably stop the drive motor so as to prevent proper operation of the defrost mechanism which requires a substantially continuous drive to function as a timer for effecting preselected cyclical defrosting operations.

SUMMARY OF THE INVENTION

The present invention comprehends an improved refrigeration apparatus control utilizing a single drive motor for controlling both the ice body making and harvesting operation and the defrost timing operation.

The control includes means for permitting continued operation of the drive motor notwithstanding a jamming or other stoppage of the ice making mechanism which would otherwise tend to stall the motor. More specifically, the invention comprehends providing a suitable clutch in the means for driving the ice making and harvesting mechanism from the drive motor to break the driving connection from the drive motor in the event of such stoppage.

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 front elevation of a refrigeration apparatus control mechanism embodying the invention;

FIG. 2 is a fragmentary enlarged section substantially along the line 2--2 of FIG. 1; and

FIG. 3 is a schematic wiring diagram of the electrical circuitry of the control mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the exemplary embodiment of the invention as disclosed in the drawing, a refrigeration apparatus generally designated 10 is shown to comprise a drive motor 11, a first control mechanism generally designated 12 for cyclically controlling the making and harvesting of ice bodies, and a second control mechanism generally designated 13 for periodically effecting defrosting of the refrigeration apparatus 10. Apparatus 10 may be mounted within a space generally designated 14 such as a freezing compartment of a combination frost-free type refrigerator-freezer apparatus. The ice bodies generally designated I are conventionally formed in a suitable mold 15 which is suitably acted upon and manipulated to effect a harvesting of the ice bodies therefrom into a subjacent collecting bin 16, as shown in FIG. 1 of the drawing. An excellent example of such a mechanism 12 is disclosed in Frohbieter U.S. Letters Pat. No. 3,382,682 owned by the assignee hereof, to which patent reference may be had for a detailed description of the ice body making and harvesting mechanism.

Defrost control mechanism 13 is schematically shown in FIG. 1 to include a control switch 17 adapted to be periodically operated by a suitable actuator 18 of mechanism 13 to energize an electric defrost heater 19 for effecting the desired defrosting of apparatus 10. Such a defrost timer control mechanism is disclosed in detail in copending application of Linstromberg et al., Ser. No. 46,921, filed June 17, 1970, owned by the assignee hereof, and to which patent application reference may be had for a detailed description of mechanism 13.

For purposes of understanding of the present invention, it need merely be understood that defrost mechanism 13 includes an input drive gear 20 meshing with a pinion 21 of a shaft extension 22 fixed to the output shaft 23 of the drive motor 11 whereby control mechanism 12 is directly driven by motor 11. Ice making and harvesting mechanism 12 includes an input drive gear 24 meshing with a pinion 25 rotatably coaxially mounted on shaft extension 22. Pinion 25 is driven directly with shaft extension 22 under normal circumstances by means of a slip clutch 26 including a backup ring 27 fixed on the shaft extension 22 forwardly of pinion 25, and a coil spring 28 extending coaxially between pinion 25 and backup ring 27, as shown in FIG. 2. Spring 28 urges a rear face 29 of pinion 25 against a forwardly facing shoulder 30 of an annular enlargement 31 at the rear end of shaft extension 22 to provide a frictionally locked connection of the pinion 25 to shaft extension 22.

In normal operation ice making and harvesting mechanism 12 controls apparatus 10 to form ice bodies in mold 15 as by the delivery of water thereto for freezing therein within refrigerated chamber 14. Thus, control mechanism 11 includes a suitable water valve operated by electric solenoid 32 (FIG. 3) controlled by a water fill valve switch 33. Control mechanism 12 further includes means for sensing the level of ice bodies collected in bin 16, illustratively comprising a sensing arm 34 which periodically sweeps through collecting bin 16. In the event that the level of collected ice bodies is below a preselected full level, control mechanism 12 continues to operate under the driving force of motor 11 to deliver ice bodies from mold 15 and to form a subsequent batch of ice bodies in mold 15 upon suitable water delivery through the water valve. In the event that the level is at the preselected full level, sensing arm 34 operates control mechanism 12 to prevent further making and harvesting of ice bodies by breaking the driving connection between gear 24 and ice mold 15. Drive motor 11 continues to drive gear 20 for timing the defrost operation.

However, should the operation of control mechanism 12 be stopped because of other reasons such as jamming of mold 15 (as by ice body I illustrated in FIG. 1), the drive from gear 24 is not so broken and, thus, if it were not for the slip clutch 26 the stopping of mechanism 12 would stall motor 11 thereby preventing continued driving of gear 20 and mechanism 13. Slip clutch 26 is arranged to permit gear 24 and pinion 25 to be stalled while yet motor 11 may continue to drive gear 20 thereby maintaining the timing functioning of drive motor 11 relative to defrost mechanism 13.

As shown in FIG. 3, refrigeration apparatus 10 includes a conventional compressor motor 35 controlled by conventional cabinet thermostat 36 in series with defrost switch 17 for refrigerating space 14 to a preselected low freezing temperature. Defrost switch 17 may comprise a single pole, double throw switch having a moving contact 17a selectively engageable with a first fixed contact 17b connected to cabinet thermostat 36, and a second fixed contact 17c connected to a single pole defrost bimetallic switch 37 in series with defrost heater 19. Moving contact 17a may be connected to one power supply lead L1 and the other side of defrost heater 19 and compressor 35 may be connected to the other power supply lead L2. A bimetallic ice maker switch generally designated 38 may include a moving contact 38a connected to drive motor 11, a first fixed contact 38b connected to power supply lead L1 and a second fixed contact 38c connected to contact 17c of switch 17.

Drive motor 11 runs substantially continuously as discussed above to provide a desired timing functioning in controlling defrost mechanism 13. When switch 17 is thrown from the position of FIG. 3 to engage moving contact 17a with fixed contact 17c thereby deenergizing compressor motor 35 and energizing defrost heater 19, drive motor 11 continues to be energized through switch 38. In the event that the temperature within space 14 rises above a preselected high temperature, switch 38 is thrown to engage moving contact 38a with fixed contact 38c. Under such high temperature conditions which would prevent forming of ice bodies in mold 15, frosting of the apparatus normally does not occur and, thus, need for continuous timed defrost sequence at this time is obviated.

Thus, under normal cycling conditions of mechanism 12, operation of water fill valve switch 33 is prevented when the level of ice bodies in the bin 16 reaches the full level without requiring the stoppage of drive motor 11. Under such circumstances, clutch 26 is not brought into play as gear 25 may rotate with shaft extension 22. However, when gear 25 is stopped as by a jamming of mechanism 12, clutch 26 permits the continued driving of gear 20 in the novel and simple manner discussed above.

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

Claims

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

1. In a refrigeration apparatus having means for making and harvesting ice bodies, control mechanism comprising: first control means for cyclically controlling the making and harvesting means to effect making and harvesting of ice bodies; a drive motor; second control means for periodically effecting defrosting of said apparatus; means connected to said drive motor for positively driving said second control means; and safety means for yieldingly driving said first control means from said drive motor to permit continued timing of the defrosting cycles notwithstanding a stoppage of said first control means.

2. The refrigeration apparatus control mechanism of claim 1 wherein said last named means includes a spring biased clutch intermediate said drive motor and said first control means.

3. The refrigeration apparatus control mechanism of claim 1 including an output pinion driven by said motor, said pinion directly driving said second control means and driving said first control means through a slip clutch.

4. The refrigeration apparatus control mechanism of claim 1 wherein said drive motor is provided with an output shaft; a first pinion fixedly carried by said shaft for driving said second control means, a second pinion carried by said shaft for driving said first control means, and said safely means comprises a slip clutch releasably driving said second pinion with said shaft.

5. In a refrigeration apparatus having a water fill valve and a defrost heater, control means comprising:

a continuously operating drive motor;

first means operated by said motor for operating said heater periodically to defrost said apparatus;

second means operated by said motor for periodically opening said valve, slip clutch means for permitting said motor to continue to drive said first means notwithstanding a stoppage of said second means.

6. The refrigeration apparatus control means of claim 5 wherein said heater comprises an electric heater and said first means includes a switch for controlling electrical energization of said heater.

7. The refrigeration apparatus control means of claim 5 wherein said valve includes an electric solenoid operator and said second means includes a switch for controlling electrical energization of said solenoid.