US 1984639 A
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Description (OCR text may contain errors)
Dec. 1.8, 1934. J. E. GRANT ET AL.
` REERIGE'RATOR- CONTROL FledFeb. 13, 19375- 2 Sheets-Shea?I l Dec. 18, 1934.
J. E. GRANT ET AL REFRIGERATOR CONTROL 2 Sheets-Sheet 2 Filed Feb. 15, 1935 J MOTOR-36 THERMQS FAT/c sw/ncu Patented Dec. 1s, 1934' PATENT ori-TCE marianna comm.
Jamel E, @nut and Reuben B. Davison, Chicago, lll.
Application P ebllllr! 13,1938; Serial No. 656.459
' IOur invention relates to refrigerating devices and particularly to means controlled by timing mechanism for interrupting the operation of refrigeration for a predetermined period. This application is a continuation in part of our appli- -clxagilon Serial No. 572,572, filed November 2nd,
This arrangement serves several useful purposes; for example, it is essential that the cooling unit or evaporator be defrosted at intervals; that is, that normal operation be suspended for a length of time sufficient to permit the temperature of the evaporator to rise and thereby cause the separation from the .unit of the surface accumulation of frost. Where this is done at long, intervals the operation requires considerable time and the raising of thebox temperature to an extent that would not be necessary if done at shorter intervals. l
Our invention contemplates the use of timing mechanism such as a clock, electrical or spring controlled, so arranged that the defrosting operation is performed every day, the motor being disconnected for the requisite time during the night. Thus the evaporator is maintained in a substantially defrosted condition at all ltimes with a resulting increase in eiilciency.
An important advantage in the use of timecontrolled automatic means for defrosting is that the defrosting may be accomplished without permitting the temperature of the interior of the box to rise to the point of bacteria activity, that is about 50 F. By setting the mechanism for frequent, relatively short defrosting periods any frost accumulation on the evaporator will be dissipated without raising the temperature of the box interior above approximately AF.
The vital and important object is to provide automatic time-controlled means, applicable to a refrigerator having thermostatic temperature control, that will at pre-determined times and for pre-determined intervals, interrupt the control by the thermostat and restore the control when the desired result has been attained.
The invention will be more readily understood by reference to the accompanying drawings, in
Fig. 5 is a front elevation of an installation as a. part of the box in which case the setting mechanism is arranged exteriorly;
Fig. 6 is an enlarged face view of the clock construction shown in Fig. 5;
Fig. 7 is a wiring diagram for one type of construction, and
Fig. 8 is a wiring diagram for a type of construction common to some devices in which an oil heater is used.
In the drawings we have illustrated a refrigerator cabinet 10 having a motor-compressorcondenser element 11 in the lower compartment and an evaporator 12 in the upper compartment. The apparatus, including the electric motor, is of a common type and is not illustrated in detail nor described pther than in association with its functions.
In the construction of Fig. 1 a clock 13 is superposed on the box, this clock being ofthe electricmotor-operated type having the usual dial and in addition two minor dials 14, 15 preferably calibrated to twenty-four hour intervals and arranged relative to certain pointers or hands mounted on the shafts 16, 17. To these shafts are fixed the cam fingers 18, 19 best shown in Fig. 2. The clock details are not new with us and we have not, therefore, illustrated the clock motor or other prime mover for effecting the necessary movement. We have illustrated a certain train of gears through which motion is imparted by the prime mover to the pinion 20 that is fixed to the' minute-hand-shaft 21 of the clock. This pinion 20 imparts movement to the gears 22, 2 3 that are rotatable andlongitudinally slidable on the shafts 16, 17, the pinion 20 being of sufficient` length to permit said gears to move longitudinally of the pinion without disengagement therefrom. Fixed to the gears 22, 23 are the face cams 24, 25 arranged to contact the cam fingers 18, 19, the arrangement being such that as the gears rotate they are shifted laterally according to the contour of the cams.
Rigidly mounted on parts of the frame of the clock are the spring arms 26, 27 each having lateral extensions that are perforated to surround the shafts. 16, 17 and to cooperate with the gears 22, 23 for bodily movement with the gears. The upper ends 28, 29 of the spring arms lie adjacent to the movable members 30, 3l of the pair of contacts through which regulation is effected. The fixed members 32, 3 3 are common and are directly connected to the positive terminal the source of electrical energy, as best shown in the diagrams of Figs. 7 and 8.
By reference to the diagrams, the cycle of operation will be apparenti. The clock motor indicated at 34 is directly connected to the source of energy and operates to openand close the respectivecontacts according to the setting of the indicators on thel dials 14. 15, the connection to the refrigerating motor 35 being directly through these contacts'and through a thermostatic switch 40, 'controlled by a thermostat 41. If, for defrosting purposes, the user wishes operation to be carried out from 12:00 to 2:00 A. M. the pointer on the righthand dia114'is set at 12:00 midnight, while the pointer on the dial 15 `is set at 2:00 A. M. According to the construction ofthe mechanism one of the contacts 30. 31
will remain closed at all times until 12:00 midnight, whereupon the closed contact 30 will snap open due to the spring action of the arm when the respective gear shifts tothe low point of the cam breaking the circuit to the refrigerating motor,` and thereby rendering the thermostatic control` 41 inoperative. The motor will thus be interrupted until 2:00 A. M. whereupon the contact 31 will be closed by the shifting f the gear 23 by riding ofi cam ringer on' the high point of the cam 25 and normal operation will be resumed by returning the control to the thermostat 41, which will continue for the balance of the 24 hour period.
Of course, if the user wishes to periodically int'errupt the operation of the motor in order to save current or for other reasons he mayset the mechanism to accomplish this result, it being entirely optional as tothe time and operation of the shut-oil.
In the construction shown in Figs. 5 and the parts remain the same `except that the clock' 36 is built in as a part of the box in which case the setting dials 37 for the various instrumentalities are connected through gears (not shown), to project outside of the casing lnsteadof behind it. It
will be understood that the knobs 37 shown at the right and left of the clock dial in Fig. 6 and marked respectively 03" and On" are used for moving the shafts 16 and 17 carrying the cam fingers 18 and 19 that serve to set the pointers on the dials 14, 15.
In Fig. 8 the diagram includes a heater coil 38 used in some types o! refrigerators for maintaining the lubricating oil in a iiuid condition. This is directly connected to the source of current and is not interrupted by the interruption of the control by the thermostat. In this diagram we have also illustrated a switch 39 in automatic defrosting connection which may be used for interrupting all operations except that of the clock and the heater coil in case one is used.
It will be understood that different forms of clock mechanism may be used and that locations and arrangements of the clock other than that shown may be utilized. For example. by suitable wiring connections the clock may be installed in the kitchen or some other room of theA house'and accomplish an added purpose.
'Ihese and other modications are considered within the scope of the invention.
The combination with a refrigerating device having an electric motor, an electric heater for oil, an evaporator and a thermostatically controlled switch for normally maintaining a temperature within the box at which frost will form on the evaporator, o1' means for periodically defrosting said evaporator, said means including clock mechanism, contacts for the power supply to said motor through said thermostat, and means for setting said clock mechanism to break said contacts at predetermined times, all Without interrupting the supply of current to said oil heater.
JAMES E. GRANT. REUBEN B. DAVISON.