US3007101A - Thermostat motor control - Google Patents

Description

Oct. 31, 1961 M. M. REDDI THERMOSTAT MOTOR CONTROL 3 Sheets-Sheet 2 Filed 001;. 25, 1956 IN V EN TOR.

F I G. 3 MULLAPUDI M- R-EDD\ MM, %M

FIG. 2

AT TO RNEY Oct. 31, 1961 M. M. REDDI 3,007,101

THERMOSTAT MOTOR CONTROL Filed 001;. 25, 1956 3 Sheets-Sheet 3 45a. 7 4-O 455/ FIG 6 FIG. 7

INVENTOR. MULLAPUDI M. REDD! AT TORNEY Patented Oct. 31., 1961 3,007,101 THERMOSTAT MOTOR CONTROL Mullapudi M. Reddi, Chicago, Ill., assignor to The Dole Valve Company, Chicago, Ill., a corporation of 1111018 Filed Oct. 25, 1956, Ser. No. 618,257 6 Claims. (Cl. 318-473) This invention relates to improvements in ice cube makers and the like and more particularly relates to an improved form of thermostatic control therefor.

A principal object of the invention is to provide a novel and improved form of thermostat simplifying the control for an ice maker and the like.

A further object of the invention is to provide a simplified and improved control means for an automatic ice maker in which a single thermostat senses the temperature of the ice cubes to initiate the ejecting operation thereof and also may reset the ice maker for a next succeeding ice cube making operation at the termination of an ice cube ejecting operation.

A further object of the invention is to provide a simplified form of thermostat particularly adapted to control the operation of ice cube makers and the like effecting one control operation at a predetermined low temperature and another control operation at a predetermined high temperature.

A still further object of the invention is to provide an improved form of thermostat sensing the temperature of the ice cubes of an ice maker and initiating an ejecting operation at the temperature of the frozen ice cubes and resetting the ice maker for a next succeeding ice making operation at an elevated temperature.

A still further object of the invention is to provide a multi-action thermostat of a novel and improved construction in which certain control operations are efiected at low temperatures and in which certain other control oper ations are effected at high temperatures, attained by the heating of the thermostat.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

FIGURE 1 is a fragmentary view in side elevation of an ice maker constructed in accordance with the invention, with certain parts thereof shown in longitudinal section;

FIGURE 2 is a fragmentary horizontal sectional view showing certain details of the drive to the ejector paddles for the ice maker;

FIGURE 3 is a fragmentary sectional view taken substantially along line IIIIII of FIGURE 2;

FIGURE 4 is an enlarged detail view of a thermostat constructed in accordance with the invention with certain parts thereof shown in section;

FIGURE 5 is a plan view of the thermostat shown in FIGURE 4; and

FIGURE 6 is an end view of the control cam for the ice maker; and

FIGURE 7 is a diagrammatic view showing the control circuit for the ice maker.

In the embodiment of the invention illustrated in the drawings, I have shown in FIGURE 1, an ice making ap paratus somewhat similar to that shown and described in my application Serial No. 608,380, filed September 6, 1956, now Patent No. 2,949,749, and entitled Automatic Ice Cube Maker, except that the motive power for ejecting the ice cubes from the ice cube tray is an electric motor in place of the heat motor shown in the aforementioned application. The ice making apparatus, therefore, need not herein be shown or described in detail.

The ice making apparatus includes generally a tray or mold 10, which may be located in heat exchange relation with respect to the evaporator or freezing chamber of a refrigerator (not shown). The tray 10 has a series of cavities 11 therein, opening to the top thereof and forming molds for freezing water in the form of individual cubes of ice when the tray is contained within a refrigerator. The cavities 11 may have the usual concave arcuate bottoms (not shown) to enable the cubes or blocks of ice to be turned from the tray by ejector paddles 12, extending laterally from an ejector shaft 13, to sweep or turn the ice cubes from the cavities 11 upon pivotal movement of said ejector paddles within and across said cavities, as is well known to the art, so not herein shown or described further.

A deflector 16 is secured to one side of the tray 10 and extends over said tray to a position adjacent the center thereof, to be engaged by the ice cubes as they are removed from the cavities by the paddles 12, and retains the ice cubes ejected from their molds in an inverted position to dry the moisture thereon and forms a slide over which said ice cubes may be pushed by the ejection of a next succeeding batch of ice cubes from the tray 10, as shown and described in my aforementioned application Serial No. 608,380.

The shaft 13 is suitably journaled in the walls of the mold 10 in vertically spaced relation with respect thereto and is directly driven from a motor 17. The motor 17 is secured to an outer side wall 18 of a housing 19 for the control of mechanism for the ice maker and extends outwardly therefrom. The motor 17 thus provides a direct drive to the ejector paddles 12 to turn or push the ice cubes from their cavities 11 upon operation of said motor.

A heater 21 (see FIGURE 7) may also extend around the bottom of the tray 10 to heat the ice cube molds and free the cubes to be ejected therefrom by the paddles 12. The heater may be of a well known form of resistor heater, such as is commonly used to heat ice cube trays to free the cubes, under the control of the thermostat sensing the frozen ice cubes, and is no part of the present invention so need not herein be shown or described further.

Referring now to the means for controlling the ice making operation, a thermostat 20 is provided to sense the temperature of the ice cube tray, to energize the heater 21 and the motor 17 to effect the ejection of the ice cubes from the tray 10. Said thermostat may also stop operation of the motor 17 at the termination of an ice cube ejecting operation and may reset the ice maker for a next succeeding operation. The thermostat may also act as a safety thermostat and as an over temperature regulator, where the ice cube tray is heated prior to the ejection of ice cubes therefrom.

The thenmostat 20 is shown as including a housing 22 for a thermal element 23, herein shown as being a well known form of power type of thermal element, such as is shown and described in the Vernet Patent No. 2,368,181, dated January 30, 1945. This thermal element has been selected for its compactness and simplicit as well as its high power and the relatively long range of travel of a power member or piston 24 there of with respect to a cylinder 25 of the thermal element, as the temperature increases to the operating temperature of the thermal element. In such types of thennal elements, a thermal medium (not shown) in the form of a fusible thermally expansible material is contained within a casing 26 for the thermal element and reacts against a membrane or deformable member (not shown), to extend the power member or piston 24 with respect to the cylinder 25, as the thermal medium reaches its fusion point. The casing 26 is sealed to the cylinder 25 by clamping a ring 27 which abuts the inner wall of the housing 22 for the thermal element.

A compression spring 29 serves as a return spring for the piston 24 and also maintains the clamping ring 27 in engagement with the housing 22. The spring 29 is seated at one end in an outer end plate 30 for the housing 22 and at its opposite end on a flange 31 of a generally bell shaped retainer 33, seated on the end of the piston 24 and extending inwardly therefrom along the cylinder 25 and clamping ring 27, when the piston 24 is in its retracted position. The outer end of the retainer 33, extending about the end of the piston 24, is of a peak like form having a rounded end 51 engaging an actuator lever 35 for pivoting said lever about the axis of a pivot pin 36, upon extensible movement of the piston 24 with respect to the cylinder 25.

The casing 26 is shown as being recessed within a wall 39 of the ice cube tray or mold 16, in intimate contact therewith for sensing the temperature of the ice cubes in said tray and accommodating the spring 29 to retractibly move the power member 24 of the thermal element to effect operation of a switch 40, as the temperature of the frozen ice cube tray drops to substantially the temperature of the frozen ice cubes in the ice cube tray 10, which may be in the nature of 25 F. Closing of the contacts of the switch 40 will energize the heater 21 to free the ice cubes from their molds and will energize the motor 17 to initiate the ejecting operation. Closing of the switch 4! will also energize a reset resistor heater 41 encircling the casing 26 and heating said casing to extend the power member 24 from the cylinder 25 and move the actuator 35 into position to accommodate resetting of the switch 40 into position to initiate a next suceeding ejecting operation, upon freezing of a next suceeding batch of ice cubes in the tray 10.

The switch 46 may be a well known form of single throw snap acting limit switch including a casing 42 having an operating button 43 slidably mounted therein and extending from opposite sides thereof and depressible in one direction, shown in in FIGURE 4 as being an upward direction to engage a movable switch arm 43a with a stationary contact 43b and complete an energizing circuit to the mold heater 2.1, the motor 17 and the reset heater 41, and depressible in an opposite direction to deenergize the motor 17 reset heater 41 and mold heater 21 (see FIGURE 7). As herein shown, the switch is mounted on a bracket 44 extending outwardly from the end plate 30 of the housing 22 and extends over the front of said housing to position the switch button 43 to be engaged by either one of two legs 45 or 46 of the actuator 35.

The actuator 35 is shown as being generally U-shaped in form and as having the pivot pin 36 extending outwardly from opposite sides thereof and pivotally mounted at its opposite ends in opposite side Walls 50 of the bracket 44, to pivot thereabout. The base of the actuator 35 is shown as being engaged by the rounded outer end 51 of the retainer 33, to effect pivotal movement of said actuator 35 about the pivot pin 36 in a clockwise direction upon extensible movement of the piston 24 from the cylinder 25. A compression spring 53, seated on the horizontal leg of a bracket 55 depending from the end plate 30 of the housing 22, engages the underside of the leg 46 of the actuator 35 to return said actuator upon retractable movement of the piston 24 within the cylinder 25, and to engage a switch button 43 and depress said button, when the temperature sensed by the thermal element 23 is at the temperature of the frozen ice cubes in the tray 10.

An interlock is provided to prevent operation of the actuator 35 to depress the button 43 and energize the motor 17, to start said motor when ice cubes discharged from the tray 10 fill an ice cube container (not shown) beyond a desired level. The interlock is shown as comprising a spring arm 56 mounted at its inner end in the end wall 39 of the tray 10 and extending outwardly from said wall. The spring arm 56 has a right angled arm 57 extending along said wall in outwardly spaced relation with respect thereto into position to engage the leg 46 of the actuator 45 and prevent the spring 53 from moving said leg upwardly to depress the switch button 43, when said spring arm is in a depressed position. The spring arm 56 is depressed and held in a depressed position, to prevent the actuator 35 from operating the push button 43, by means of an overfill arm 59, shown as having a ball 60 on the free end thereof. The overfill arm 59 extends from a collar 61 on a shaft 63, through a slot 64 in a laterally extending portion of the end wall 39, spaced outwardly of the ice molds in the tray 16. The shaft 63 is journaled for pivotal movement about an axis extending transversely of the shaft 13 and has a cam 65 thereon, extending radially therefrom and having engagement with the spring arm 56, to hold said spring arm into position to engage the leg 46 of the actuator 35 and hold said leg from movement in a direction to depress the push button 43 when the level of ice cubes discharged from the tray 10 is sufiicient to raise the overfill arm 59 to dotted line position A, shown in FIGURE 1.

The overfill arm 55' is raised out of the way of the ice cubes as they are ejected from the tray 16 over the deflector 16 by means of a cam 66 on the ejector shaft 13. The cam 66 uniformly rises to a peak 67, engageable with a roller 63 extending from the face of a disk '76 keyed or otherwise secured to the inner end of the shaft 63. Thus, during operation of the motor 17 and shaft 13 to eject ice cubes from the tray 10, the face of the cam 66 engaging the roller 69 will turn the shaft 63 and raise the overfill arm 59 from the solid line position shown in FTGURE 1 through position A up to the dotted line position B shown in this figure, to accommodate the ejection of ice cubes along the deflector 16 without interfering with said overfill arm. During upward movement of the overfill arm 59, peaks 71 and 72 of the cam 65 will successively pass over a peaked portion 73 of the spring arm 56 to depress said spring arm. Since, however, a circuit is made to the motor 17 upon the initial depression of the push button 43 by operation of the leg 46 of the actuator 35, the motor 19 will remain energized.

The overfill arm 59 is shown in FIGURE 1 in dotted line in position C, which may be attained by engaging said arm within a slot (not shown) in a depending slotted portion 75 of the cover for the ice maker. When the overfill arm 59 is in this position, the spring arm 56 is depressed and the actuator 35 will be ineffective to energize the motor 17 to start operation of the ice maker.

A resetting means is provided for the push button 43, to reset said push button at the termination of an ice making operation, which is herein shown as being a pivoted bellcrank lever 77 pivoted to a bracket 79 extending inwardly from the end wall 18 of the housing 19. The bellcrank 77 is pivoted on the bracket 79 on a pivot pin 81 and has an upright arm having an engaging end portion 83 engageable with an end face 84 of a cam 85, keyed or otherwise secured to the shaft 13 for rotation therewith. The engaging end portion 83 of the bellcrank 77 is biased into engagement with the end face 84 of the cam 85 by a compression spring 86, which is lighter than the spring 53 which biases the leg 46 of the actuator 35 toward the opposite end of the push button 43 from the leg 45 of said actuator. This is to prevent the spring 86 from holding the spring 53 from depressing the push button 43 to initiate an ice cube ejecting operation. The bellcrank 77 has a horizontally extending arm 87 extending over and engaging a lever 88 pivoted to the bracket 79 and engaging the push button 43 underneath the leg 45 of the actuator 35.

The cam 85 has a radially extending slot 50 opening through the face thereof, through which the engaging end portion '83 of the bellcrank 77 may pass, to accommodate the spring 86 to pivot the bellcrank 77 in a counterclockwise direction and depress the lever 88 and reset the push button 43, and thus disengage the movable switch arm 43a from the contact 43b and deenergize the energizing circuit to the motor 17 at the termination of the ice making operation.

In operation of the ice maker, Where there are no ice cubes in storage and the water in the ice cube tray is frozen, the overfill arm 59 will be in the solid line position shown in FIGURE 1. The spring 29 will then have retractibly moved the piston 24 within the cylinder 25 a distance sufiicient to accommodate the spring 53 to move the leg 46 of the actuator 35 into engagement with the push button 43 and depress said push button. At the same time, the push button 43 will pivot the lever 88 and bellcrank 77 in a clockwise direction and withdraw the projecting end portion 83 of said bellcrank from the slot 90 in the face 84 of the cam 85. At this time, the motor 17 will be energized but will be held from operation until the bellcrank is outside of the slot 90, said slot having a beveled face 91 to accommodate rotation of the cam 85 as the bellcrank 77 is being withdrawn therefrom. The motor 17 will then start to rotate and rotatably drive the shaft 13 and the ejector paddles 12 thereon to turn ice cubes from the cavities 11 in the tray 10. Energization of the motor 17 will also energize the resistor heater 41 and heat the casing 26 of the thermal element 23 to effect extensible movement of the power member 24 thereof and turn the actuator 35 in a clockwise direction into position to accommodate resetting of the thermal element at the termination of an ice making operation. During this operation, the plane face 84 of the cam 85 is engaged by the engaging end portion 83 of the lever 77. This prevent-s the spring 86 from operating the bellcrank 77 to depress the lever 88 and push button 43 to open the switch 40 and deenergize the ice cube maker.

At. the same time the cam 66 will engage the roller 69 and lift the overfill arm 59 to position B shown in FIGURE 1. The peaks 71 and 72 of the cam 65 will then come into engagement with the spring arm 56. This will depress said spring arm to engage the leg 46 of the actuator 35, but will have no effect, since the leg 46 of the actuator 35 has already depressed the push button 43 to close the switch 40 and energize the motor 17, and the switch will remain closed until the push button 43 is reset.

Continued. clockwise movement of the actuator 35 will move the leg 46 away from the button 43 of the switch 40 against the spring 53. As the ice cubes are turned from their molds by the ejector paddles 12 and the paddles are back in position to. effect another ice making operation, the projection 83 on the bellcrank 77 will drop into the slot 90. The spring 86 will then move the bellcrank 77 in a counterclockwise direction to depress the lever 88 and reset the push button 43. This will open the switch 40 and deenergize the motor 17, mold heater 21 and resistor heater 41. The projection 83 on the bellcrank 77 will then hold the motor 17 and the shaft 13 in position for a next succeeding operation until the thermal element 23, sensing the temperature of the ice cubes, again accommodates movement of the actuator 3-5 by the spring 53in 'a" counterclockwise direction, to depress the push button 43'and move the projecting portion 83 of the bellcrank 77"out of the slot 90 and again energize the motor17, assuming there are insufficient ice cubes in storage to raise the overfill arm 59 to position A shown in FIGURE 1.

. If, however, there should be suflicient ice cubes in storage to raise the overfill arm 59 to position A shown in FIGURE 1, then the spring arm 57 will be depressed by the cam 65 engaging the peaked portion 73 thereof and will be held in position to hold the leg 46 of the actuator 45 from depressing the push button 43.

It should here be understood that the resistor heater 41 acts as a reset to reset the actuator 35 in position to accommodate the bellcrank 77 to reset the switch 40 at the termination of an ice cube making operation, but that said resistor heater effecting extensible movement of the power member 24, may also operate the actuator 35 in a clockwise direction to engage the lever 88 and depress the push button 43 to open the switch 40 in a predetermined delayed time interval, if for any reason the motor 17 should become stalled or the bellcrank 77 should fail to drop into the slot 90, and also may act as an over temperature cut-out should the resistor heater 21 become too hot.

It should further be understood that where the ice cube tray is heated by a resistor heater, that the reset resistor 41 may be dispensed with, and the resistor heater may serve to heat the thermal element and reset the actuator 35, and also may move the actuator 35 to depress the push button 43 and deenergize the motor 17 upon over temperature conditions.

It may be seen from the foregoing that a simple, novel and efiicient thermostat and control for an ice maker has been provided in which the sensing of the temperature of the freezing ice cubes is attained by the thermostat to effect the initiation of an ejecting operation by retractible movement of the power member of the thermal element of the thermostat, in which the thermostat holds the motor energized under control of the reset bellcrank, and in which extensible movement of the power member moves the actuator into position to accommodate resetting of the thermostat at the termination of an ice cube ejecting operation, and that the thermostat may also act as a safety thermostat to deenergize the ice maker upon failure of any kind, or upon over temperature conditions of the mold heater.

It will be understood that various modifications and variations of the present invention may be effected without departing from the spirit and scope of the novel concepts thereof.

I claim as my invention:

1. In a thermostat, an electrically energizable motor, a shaft driven thereby, a thermal element adapted to sense the temperature of frozen water and having a casing containing a fusible thermally expansible material, a power member extensible with respect to said casing upon predetermined increases in temperature, a switch having a casing having a depressible switch button slidably mounted therein for extension from either side thereof, said switch having electrical connection with said motor to energize said motor in one position of said push button and deenergize said motor in another position of said push button, a pivoted actuator for said switch having engagement with said power member, spring means for returning said power member, other spring means engaging said actuator and biasing said actuator to follow said power member on retractable movement thereof to depress said switch button to complete an energizing circuit to said motor, a cam on said motor shaft having a slot in the face thereof indicating a starting position of said motor, a pivoted lever, spring means engaging said lever with the face of said cam and moving the same into said slot upon registry of said slot with said pivoted lever, a reset lever operated by pivotal movement of said pivoted lever into said slot for moving said push button toa reset position by operation of the biasing spring for said pivoted lever, to deenergize said motor and hold said motor in position to initiate a next succeeding operation, and means for heating said casing to effect extensible movement of said power member to move said actuator into a resetting position.

I 2. In a thermostat, a motor, a shaft driven thereby to effect a power operation, a thermal element adapted to sense the temperature of frozen water and having a casing containing a fusible thermally expansible material, a power member extensible with respect to said casing upon predetermined increases in temperature, a switch having a casing having a depressible switch button slidably mounted therein for extension from either side thereof,

said switch having electrical connection with said motor to energize said motor in one position of said push button and deenergize said motor in another position of said push button, a pivoted actuator for said switch having engagement with said power member, spring means for returning said power member, other spring means engaging said actuator and biasing said actuator to follow said power member on retractable movement thereof to depress said switch button to complete an energizing circuit to said motor, a cam on said motor shaft having a slot in the face thereof indicating a starting position of said motor, a pivoted lever, spring means engaging said pivoted lever with the face of said cam and moving the same into said slot upon registry of said slot with said pivoted lever, a reset lever operated by pivotal movement of said pivoted lever into said slot for moving said push button to a reset position by operation of the biasing spring for said pivoted lever, to deenergize said motor and hold said motor in position to initiate a next succeeding power operation, and a resistor heater energized upon closing of said switch for heating said casing to effect extensible movement of said power member and pivotable movement of said actuator into position to accommodate said reset lever to operate said push button to reset said push button and switch, and deenergize said motor and resistor heater.

3. In a thermostat, a motor, a shaft driven thereby to effect a power operation, a thermal element adapted to sense the temperature of frozen water and having a casing containing a fusible thermally expansible material, a power member extensible with respect to said casing upon predetermined increases in temperature, a switch having a casing having a depressible switch button slidably mounted therein for extension from either side thereof, said switch having electrical connection with said motor to energize said motor in one position of said push button and deenergize said motor in another position of said push button, a pivoted actuator for said switch having engagement with said power member, spring means for returning said power member, other spring means engaging said actuator and biasing said actuator to follow said power member on retractable movement thereof to depress said switch button to complete an energizing circuit to said motor, a cam on said motor shaft having a slot in the face thereof indicating a starting position of said motor to initiate a power operation, a pivoted lever, spring means engaging said pivoted lever with the face of said cam and moving the same into said slot upon registry of said slot with said pivoted lever, a reset lever operated by pivotal movement of said pivotal lever into said slot for moving said push button to a reset position by operation of the biasing spring for said pivoted lever, to deenergize said motor and hold said motor in position to initiate a next succeeding power operation, a resistor heater energized upon closing of said switch for heating said casing to effect extensible movement of said power member and pivotable movement of said actuator into position to accommodate said reset lever to operate said push button to reset said push button and switch, and deenergize said motor and resistor heater, a safety control arm, and an interlock between said safety control arm and said actuator member, preventing operation of said actuator to operate said push button to close said switch.

4. In a thermostatic control, an electrically energizable motor, a thermal element having a casing containing a fusible thermally expansible material adapted to sense certain low temperature conditions and having a power member retractable within said casing upon certain reductions in temperature and extensible from said casing upon certain increases in temperature, a spring for retractably moving said power member upon certain reductions in temperature, a switch having a depressible switch button and connected with said motor to close an energizing circuit thereto upon depression of said switch button, an actuator for said switch pivoted for movement toward and from said switch, spring means moving said actuator in a direction to depress said switch button upon retractable movement of said power member, and means for resetting said switch comprising a cam rotatably driven by said motor, a follower member engageable with said cam, a resetting member operated by said follower member, for moving said switch button in a direction to reset said switch, said follower member being held from movement in a resetting direction by said cam and registering with said cam in a predetermined position of said cam, and movable when in this position to operate said resetting member to reset said switch button.

5. In a thermostatic control, a thermal element having a casing containing a fusible thermally expansible material adapted to sense certain predetermined low temperature conditions and having a power member extensible upon certain high temperature conditions, a spring retractably moving said power member upon certain low temperature conditions, a device to be operated including an electric motor, an energizing circuit for said motor including a switch, a pivoted actuator for said switch, operated in one direction upon extensible movement of said power member to reset said switch into an open position and operated in another direction upon retractable movement of said power member to close said switch and operate said motor, means resetting said switch into an open position comprising a resetting lever having operative connection with said switch, a cam rotatably driven by said motor and having a flat cam face having a radially extending slot therein, a follower engageable with said cam face and having operative connection with said resetting lever, a spring biasing said follower into engagement with said cam face and moving said follower within said slot to reset said switch upon rotation of said cam a predetermined number of degrees, said actuator having operative engagement with said resetting lever and moving said lever in a resetting direction upon extensible movement of said power member upon certain over-temperature conditions.

6. A thermostatic control device in accordance with claim 5 in which a resistor heater encircles said casing of said thermal element and is energized upon energization of said motor to eifect extensible movement of said powor member to move said actuator to open said switch in cases of failure of said motor to rotate.

References Cited in the file of this patent UNITED STATES PATENTS 2,316,003 Kriechbaum Apr. 6, 1943 2,489,896 Kempton Nov. 26, 1949 2,561,437 Cobb July 24, 1951 2,662,992 Frey Dec. 15, 1953 2,717,497 Knerr Sept. 13, 1955 2,717,498 Shagalofi Sept. 13, 1955 2,744,390 Partsch May 8, 1956 2,747,375 Pichler May 29, 1956 2,778,198 Heath Jan. 22, 1957 4 ,008 Barton July 22, 1958

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