Flexing tray ice-maker with AC drive

An ice-maker provides a reversible AC motor whose direction is changed at a first and second stop positioning the tray in a filling position and an ice cubes discharging position, respectively. A bail arm may introduce an additional stop preventing discharge of ice when an ice bin is full. User controls may allow the user to set a water fill time based on local water pressure conditions. An ice tray incorporating an ice sensor may releasably connect to the ice-making machine for ready replacement.

FIELD OF THE INVENTION

The present invention relates to ice-making machines for home refrigerators and the like and specifically to an ice-making machine providing a flexible tray for ejecting ice cubes while using an AC drive.

BACKGROUND OF THE INVENTION

Household refrigerators commonly include automatic ice-makers located in the freezer compartment. A typical ice-maker provides an ice cube mold positioned to receive water from an electric valve that may open for a predetermined time to fill the mold. The water is allowed to cool until a temperature sensor attached to the mold detects a predetermined low-temperature point where ice formation is ensured. At this point, the ice is harvested from the mold by a drive mechanism into an ice bin positioned beneath the ice mold. The amount of ice in the ice bin may be checked through the use of the bail arm which periodically lowers into the ice bin to cheek the ice level. If the bail, is blocked in its descent by a high level of ice, this blockage is detected and ice production is stopped.

One method of harvesting ice cubes from the molds employs a mold heater. Typically, in this case, the ice tray will be a metal die-cast part incorporating an electrical resistance heater which heats the ice tray to release the ice when the tray is inverted by a motor. The electrical resistance heater and the ice-maker motor normally operate directly at a fine voltage of about 120 volts AC eliminating the need for additional power processing for the motor51or, in some reduced complexity embodiments, sophisticated control electronics in the associated refrigerator.

An alternative method of harvesting ice cubes uses a flexible ice tray which is twisted by a DC motor receiving power and control signals from an external DC power source and control electronics in the associated refrigerator. Twisting of the tray ejects the ice cubes from the tray.

This latter approach can operate with considerable energy savings but is not available on some lines of refrigerators which do not provide the necessary DC power supplies for the motor or more sophisticated control electronics for producing the necessary control signals.

SUMMARY OF THE INVENTION

The present invention provides an ice-maker using a flexible tray but operating with an AC motor to eliminate the need for DC power processing not available in some refrigerator lines. Simple and precise bidirectional control of the AC motor is provided by interacting stops on a drive gear and the bail arm. The invention also provides an extremely simple user interface for an ice-maker allowing testing of the operation of the ice-maker, the outputting of error codes, and improved adjustment of tray fill level in low-pressure environments according to a teaching routine that may be conducted by the user. In addition, the ice tray provides a mechanical and electrical connector allowing it to be replaced through a simple unplugging and plugging operation.

Specifically then, in one embodiment, the present invention provides an ice-maker having an ice tray providing multiple cube forming compartments open on an upper face of the ice tray for receiving water to mold ice. A motor unit has a connector attachable to the ice tray to rotate the ice tray for filling of the ice tray with water in a first position and warpage of the tray to discharge the ice cubes from the tray in a second position. The motor unit further provides: (a) an AC motor operable to rotate the connector bi-stably in two directions; (b) a first and second stop blocking the rotation of the AC motor when the tray is in the first and second positions to cause reversal of the direction of operation of the AC motor at those positions; and (c) a position sensor sensing at least one rotated location of the tray. A controller responds to the position sensor to control power to the AC motor to provide a cycling of the tray between the first and second positions for ice making.

It is thus a feature of at least one embodiment of the invention to provide an extremely simple auto reversing mechanism for use in an ice-maker.

The ice-maker may further include an ice bin positioned beneath the ice tray to receive ice cubes discharged from the ice tray in the second position and a bail arm operable by the AC motor to descend into the ice bin as the tray moves from the first position to the second position. The ice-maker may further include a third stop blocking the rotation of the AC motor when the tray is between the first and second position before warpage of the tray, and the bail arm may provide a movable finger interacting with the third stop only when the bail arm is blocked at a predetermined elevation from descent into the ice bin indicating a full state of the ice bin, the interaction of the movable finger with the third stop reversing the AC motor before it reaches the second position.

It is thus a feature of at least one embodiment of the invention to employ a stop mechanism automatically reversing the AC motor to sense and respond to a full ice bin without the need for additional bail arm height sensing contacts or the like.

The movable finger may further interact with the first and second stops to block rotation of the AC motor at the first and second stops.

It is thus a feature of at least one embodiment of the invention to use the bail arm finger to provide a common interference mechanism for the first, second and third stops eliminating the need for additional structure.

The AC motor may be an AC synchronous motor.

It is thus a feature of at least one embodiment of the invention to make use of the bi-stable reversibility of the synchronous motor to simplify the mechanism of an ice-maker. It is another object of the invention to make use of a motor that can directly receive line power without the need for voltage regulation circuitry.

The controller may operate to provide power to the AC motor when the tray is between the first and second positions and to selectively stop the AC motor at the first and second positions,

It is thus a feature of at least one embodiment of the invention to cycle the tray between various positions and to bold the tray at those positions using simple power control of an AC motor.

The connector may be axially connected to a gear having the first, second and third stops on a surface of the gear and the AC motor shaft may communicate with the gear through at least one additional gear.

It is thus a feature of at least one embodiment of the invention to control mechanical advantage to the AC motor so that it may be indifferent to normal frictional and tray warpage forces experienced during operation of the ice tray while nevertheless being reversible by mechanical stops.

The ice-maker may provide an electrically actuatable valve communicating with the controller to be activated by the controller for delivering water to the ice tray in the first position and may include at least one switch actuatable by a user of the ice-maker to open the valve at a first tune and close the valve at a second time indicating an amount of time necessary to fill the ice tray; and wherein the controller stores an indication of the amount of time to use to control the electrically actuatable valve at subsequent times when the tray is in the first position for filling with water.

It is thus a feature of at least one embodiment of the invention to provide a simple mechanism for the consumer to adjust for varying water pressures such as may affect filling of the ice tray.

The ice tray includes a sensor communicating with at least one cube-forming compartment to sense the formation of ice, and the connector may releasably attach to the ice tray and include releasable electrical contacts communicating with corresponding contacts in the ice tray and wherein the sensor provides electrical signals indicating the formation of ice through the releasable electrical contacts of the connector to the controller.

It is thus a feature of at least one embodiment of the invention to provide a thermal sensing ice tray that can be readily replaced by disconnecting then reconnecting a connector providing both mechanical and electrical connection. This allows improved repairability of the ice-maker or the ability to use a variety of different ice trays providing different sizes or ice cube geometries.

The ice tray may include a water receiving chute extending upward therefrom and providing a sloping surface diverting downwardly flowing water across the upper face of the ice tray.

It is thus a feature of at least one embodiment of the invention to reduce splashing of the water entering the ice tray at different pressures through the use of an integrated diverter chute.

The ice-maker may further include a slip ring system providing an electrical path from the releasable electrical contacts of the connector to the controller with rotation of the connector.

It is thus a feature of at least one embodiment of the invention to eliminate interconnecting wiring such as may flex and break during operation of the ice-maker and which can interfere with replacement of the ice tray if damaged during repetitive flexing.

The slip ring system may provide a set of rotating wipers attached to the connector and communicating with stationary conductive traces to provide the slip ring system.

It is thus a feature of at least one embodiment of the invention to provide a slip ring system that can integrate with a position sensor using similar mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now toFIG. 1, an ice-maker10may include an ice tray12for receiving water and molding it into frozen ice cubes17of arbitrary shape. The ice tray12may be positioned adjacent to ice harvest drive mechanism14operating to remove cubes from the mold when they are frozen, for example, by inversion and distortion of the ice tray12. The ice tray12may be positioned above an ice storage bin15for receiving cubes17therein when the latter are ejected from the ice tray12.

The ice harvest drive mechanism14may have a drive coupling16exposed at a front wall18of a housing20of the ice harvest drive mechanism14and communicating with the mold12or comb. The drive coupling16may rotate about an axis22along which the ice tray12or comb extends.

The right wall24of the housing20, flanking the front wall18, may support one end of a bail arm30extending generally parallel to axis22allowing the bail arm30to pivot about a horizontal axis32generally perpendicular to axis22and extending from the right wall24. As so attached, the opposed cantilevered end of the bail arm30may swing down into the ice storage bin15to contact an upper surface of the pile of cubes17in the ice storage bin15to determine the height of those cubes17and to deactivate the ice-maker10when a sufficient volume of cubes17is in the ice storage bin15to prevent full descent of the bail arm30. The bail arm30may be a thermoplastic material attached to a rotatable shaft36extending along axis32through the housing20.

A water valve19may receive tap water from a supply line21to provide water into the ice tray12under the control signals generated by the ice harvest drive mechanism14as will be discussed below.

Referring now toFIGS. 1 and 2, the drive coupling16may be a center hub of a drive gear50being part of a gear train52ultimately driven by a single-phase, synchronous AC gear motor51. The gear train52provides an increase in torque and a reduction in rotation speed of the motor to turn the drive gear50at about two revolutions per minute. The drive coupling16may support axially-extending left and right spring-loaded conductive pins55and corresponding left and right radially-extending conductive wipers57attached to respective ones of the left and right conductive pins55. A front face54of the drive gear50opposes a printed circuit board46supporting arcuate traces58that may contact on the conductive wipers57with rotation of the gear50and drive coupling16about axis22. The interaction of the conductive wipers57and arcuate traces58provides an encoder that indicates a rotational position of the gear50, for example, as described in U.S. patent application Ser. No. 2015/027629 filed Oct. 22, 2013, and hereby incorporated by reference and discussed in greater detail below. In addition the conductive wipers57and arcuate traces58provide a slip coupling communicating electrical signals from the left and right spring-loaded conductive pins55to the printed circuit board46and ultimately to a microcontroller59.

The microcontroller59including a processor, computer memory holding a stored program, and input/output circuits that may communicate with other components on the printed circuit board46, including the traces58, provides inputs related to the rotational position of the gear50. The microcontroller59may also communicate with a three-color (RGB) LED61as will be discussed below and a first and second switch63. Output signals from the microcontroller59may control the AC motor51and the electric valve19(shown inFIG. 1) connecting and disconnecting these components from the AC line voltage using a thyristor or the like communicating with the microcontroller59on the printed circuit board46. The operation of the ice-maker10may therefore be controlled through the program stored in the computer memory of the microcontroller59as will be discussed below.

Referring now toFIG. 3, the rear face of the gear50may provide for a rim60extending rearward and parallel to axis22around the periphery of the gear50. A reversing arm62extending radially from the shaft36of the bail arm30perpendicular to axis32may rest on the rim60as the gear50turns, pulled against the rim60by the weight of the bail arm30. The rim60may provide for a cam surface64that may raise and lower the bail arm30with rotation of the gear50, the cam surface64extending progressively inward from the outer circumference of the gear50with clockwise rotation of the gear50with respect to the reversing arm62.

Extending radially inward from the rim60is a first home-stop66presenting a radial face that may abut the reversing arm62preventing further rotation of the gear50in a clockwise direction past the home-stop66as depicted. Approximately halfway around the rim60is an end-stop68also providing a radial face that may abut the reversing arm62preventing further counterclockwise rotation of the gear50past the end-stop68. When the home-stop66abuts the reversing arm62, the ice tray12(shown inFIG. 1) is in its upright position ready to receive water. Conversely when the end-stop68abuts the reversing arm62, the ice tray12is inverted and fully distorted for the ejection of ice cubes17.

Partway between the home-stop66and end-stop68and extending radially outward from the center of the rear face of the clear50is a bin-full stop69having a limited radial extent presenting a gap between the outermost radial edge of the full-bin stop69and the inner surface of the rim60.

Referring now toFIGS. 1, 2, 3, 4, and 8, during most of the operating time of the ice-maker10, the gear50will be in the home position72awith home-stop66abutting a right side (as depicted) of the reversing arm62with the AC motor51turned off by the microcontroller59. At a predetermined interval determined by a timer in the microcontroller59and its executed program and sufficient time for water in the ice tray12to have frozen or a signal from a thermistor to be described (approximately −70 degrees centigrade), the AC motor51may be activated. As is understood in the art, a single-phase AC motor will operate in either direction with a preferred direction normally controlled by a ratchet. In this case, there is no ratchet and the abutment of reversing arm62and home-stop66serve to encourage starting of the AC motor51to rotate the gear50in a counterclockwise direction as indicated by arrow72.

Referring now toFIG. 5, with counterclockwise rotation, the reversing arm62will move along, then past, the cam surface64allowing the bail arm30to descend into the ice bin15. If the ice bin15is sufficiently empty to allow full descent of the bail arm30(as shown inFIG. 5) then the reversing arm62can pass beneath the full-bin stop69permitting continued rotation of the gear50by about 82 degrees until the reversing arm62abuts the end-stop68as shown inFIG. 7and as indicated by state70bofFIG. 8. At this point, the ice tray12is twisted so as to discharge ice cubes17into the bin15. After sufficient delay for full ejection of the ice cubes17during which the microcontroller59may turn off the AC motor51, the AC motor51is again activated causing the gear50to begin to move in a clockwise direction74ultimately limited by the abutment of the reversing arm62and the end-stop68.

The ice tray12again returns to its upright position at the home refill state70cat which time the motor51is deactivated by the microcontroller59. The microcontroller59then may activate the valve19for a programmable fill time that will be discussed further below. After conclusion of the fill time and once the thermistor resistance indicates approximately zero degrees centigrade (indicating the presence of water), the ice-maker10reverts to the home state70awithout further rotation of the gear50.

Referring now toFIGS. 1, 2, 3, 6, and 8, in the event that the hail arm30cannot fully descend into the ice bin15as blocked by ice cubes17, then the reversing arm62will not drop sufficiently to avoid contacting the bin-full stop69. This contact between the reversing arm62and the bin-full stop69is indicated by state70dinFIG. 8. This interference causes reversal of the AC motor51returning the gear50to the home position shown inFIG. 4. Failure to reach the end position of end-stop68, however, is recognized by the microcontroller59through the encoder described above which causes the microcontroller59to eliminate the home refill state70c.Nevertheless, by returning to the position of the home state70a,the bail arm30is lifted out of the ice storage bin15to prevent obstruction when the ice storage bin15is withdrawn by the user.

Referring now toFIGS. 1, 2 and 9, the LED61and switches63may be accessible outside of the housing20(optionally through a releasable cover) so that a first of the switches63(designated S1) may be activated by a user as detected by the microcontroller59per decision block80. This detection may cause the program to indicate a calibration mode using the LED61and to activate the fill valve19outside of the normal operation of the ice-maker10as indicated by process block82and also to start operation of a timer as indicated by process block84. The user may watch the fill level of the ice tray12and when a sufficient height has been obtained to completely fill the ice tray12to a desired level, release the pushbutton S1as detected by process block86. This release causes a new fill time to be recorded per process block88such as will be henceforth used in the home refill state70cas discussed above. This ability of the user to set the fill time allows more consistent ice tray filling under conditions of low pressure (for example, in houses with well water) where constant flow valves may be ineffective.

The LED61and the other switch63may be used, for example, to run other diagnostic tests, for example, initiating a fill cycle or a harvesting of ice. In addition the LEDs61may flash or change color to indicate various failure modes in an extremely compact user interface suitable for the difficult environments of the interior of a refrigerator.

Example constructions of the gear train52and of other elements and components of the ice harvest drive mechanism14are described in U.S. patent application Ser. No. 2012/0186288 hereby incorporated in its entirety by reference.

Referring now toFIGS. 10 and 11, the ice fray12may incorporate a temperature sensor90, for example, a thermistor or other temperature sensing element positioned beneath the ice tray12in close proximity to the volume holding a cube17so as to sense a temperature of that volume. Temperatures above the freezing point generally indicate incomplete freezing of the cubes whereas temperatures below freezing indicate that the cube has frozen and no additional phase change is occurring.

The temperature sensor90may communicate by conductors92to a connector94having upwardly extending blades96that may be received within corresponding slots98in an end of the ice tray12. The temperature sensor, conductors, and connector94may be held in position by a cover plate99stepping into the bottom of the ice tray12.

The slots98in the ice tray12receiving the blades96may communicate with a socket100, the latter mechanically and releasably interengaging with the drive coupling16to support the ice tray12for rotation by the coupling16. When the drive coupling16is in the socket100, the connector pins55electrically connect to the blades96thereby also providing an electrical as well as a mechanical connection between the drive coupling16and the ice tray12.

Referring still toFIG. 11, as noted above the connector pins55may be spring-loaded by means of helical compression springs102into engagement with the blades96. The helical compression springs102may be electrically conductive to provide electrical communication between corresponding ones of the pins55and the conductive wipers57extending radially out from the drive coupling16having fingers106slidably communicating with the traces58on the printed circuit board46.

Referring now toFIG. 12, in one embodiment, conductive wiper57may include three electrically intercommunicating fingers106and may communicate between one of the pins55and one of three concentric circularly constrained traces58a,58b,and58c.In one embodiment, the innermost trace58cmay be connected to ground and extend approximately halfway around its circular path so that the rightmost conductive wiper57a(as depicted inFIG. 12) will be grounded when the tray is in its normal upright position for filling and freezing (a shown inFIG. 12). Conversely the left side conductive wiper57bwill connect only to trace58bwhich in turn connects to a terminal110providing a temperature signal of the temperature sensor90(shown inFIG. 10). In this way the temperature sensor90may be read during the freezing of the ice cubes and yet there is no flexing wire connection between the temperature sensor90and the printed circuit board46and hence the microcontroller59, such as could break or interfere with removal of the ice tray12.

In the fill position as shown inFIG. 12, the outer trace58ais grounded through the right conductive wiper57aand a signal from this trace provides a home signal112indicating that the tray is in the home or filling position.

With clockwise rotation of the drive coupling16carrying with it the conductive wipers57as the ice tray is moved to its flexing and discharging position, conductive wiper57awill move off of the conductive portion of trace58aindicating a movement from the home position. At an arbitrary angular motion, the conductive wiper57awill contact a second portion of the outer trace58aproviding an eject signal114indicating that the tray is in the eject position to the microcontroller.

Referring now toFIG. 13, in one embodiment the ice harvest mechanism14may include an upper horizontal panel116extending over the ice tray12when the ice tray12is attached to the ice harvest mechanism14. Extending downward from one end of the upper panel116is the housing20holding the motor drive unit shown inFIG. 2. The opposite end of the upper panel116provides an opening118through which water may be discharged downwardly from water valve19into the ice tray below the upper panel. For this purpose, the ice tray12may have an upwardly extending chute120at one end of the ice tray12receiving the downwardly discharged water as indicated by arrow122. This falling water is received into the chute120which guides the water into the compartments in which the cubes17will be formed. This chute120is attached integrally to the ice tray12to rotate therewith and provides a sloping guide surface124gradually diverting the water from its downward, direction to a direction along axis22over the compartments holding the cubes17. Sidewalls128flank this diverted water to help contain it in the correct direction. By integrating the chute120in with the ice tray12, reduced splashing and water loss close to the tray12may be avoided and the greater height of the chute112permits a more gradual diversion of the water also preventing splashing.

An upper surface of the upper panel116proximate to a wall130of the refrigerator may support upwardly extending tabs132for mounting the icemaker10against the wall130. The tabs132may have rearwardly extending slots134to engage screws or shoulder screw's136projecting horizontally from the vertical face of the wall130as the icemaker10is moved rearward providing a simple installation of the icemaker10in a refrigerator from the front of the refrigerator. The slots134may have a constriction136allowing them to snap over the shaft of the screws136to prevent inadvertent dislodgment of the icemaker10. The screws136may then be tightened further over the tabs132.

The term “cube” should be understood to be an ice element not limited to any particular shape such as a cube. Generally, the invention contemplates at multiple different ice cube geometries may be used including cylinders, hemi cylinders, hemispheres and the like.