ICE MAKER WITH PIEZO DIELECTRIC ELASTOMER SENSOR
An ice maker includes, among other things, an ice cube mold, an ice cube remover and a force sensor comprising a piezo dielectric elastomer (PDE). The ice cube mold has at least one cavity for receiving liquid. The ice cube remover is configured to apply a removal force to either the mold or an ice cube. The force sensor is provided on either the mold or the remover and provides an output indicative of the removal force. Upon the removal of an ice cube from the cavity, the ice cube remover applies a removal force to the mold or the ice cube to effect the removal of the ice cube from the cavity and the force sensor outputs a signal indicative of the removal force.
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This Application represents a divisional application of and claims priority to U.S. patent application Ser. No. 14/476,796 entitled “Ice Maker with Piezo Dielectric Elastomer Sensor”, filed Sep. 4, 2014, currently allowed, and further claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 61/873,911, filed on Sep. 5, 2013, the entire disclosures of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTIONThe freezer compartment of a residential refrigerator may include an automatic ice maker. An ice maker typically includes an ice mold for receiving water and forming ice cubes while the water freezes. Once the molded ice cubes are frozen, a motor either twists the ice mold or rotates an arm to eject the ice cubes out of the mold. The ejected ice cubes may then collect in a bin until dispensed from the freezer compartment.
SUMMARY OF THE INVENTIONThe invention relates to an ice maker comprising: an ice cube mold having at least one cavity for receiving liquid; an ice cube remover configured to apply a removal force to at least one of the mold and ice cube; a force sensor comprising a piezo dielectric elastomer (PDE) provided on one of the mold and remover and providing an output indicative of the removal force; wherein upon the removal of an ice cube from the cavity, the ice cube remover applies a removal force to one of the mold and ice cube to effect the removal of the ice cube from the cavity and the force sensor outputs a signal indicative of the removal force.
In the drawings:
Three basic configurations of refrigerators with a freezer compartment include a side-by-side configuration, a top freezer configuration and a bottom freezer configuration. As shown in
The ice maker 16 may mount to the wall 18 of the freezer compartment 12. Alternatively, the ice maker 16 may mount to the door 20 of the freezer compartment 12 or attach to a base 24 that in turn may mount to the wall 18 or door 20 of the freezer compartment 12. The ice storage bin 22 is configured to receive and then store ice ejected from the ice maker 16 and may be positioned on the door 20 or beneath the ice maker 16 in the freezer compartment 12.
Referring now to
Referring now to
During an ice harvesting operation, rotation of one end 122 of the ice cube mold 100 without concurrent rotation of the opposite end 126 may effect a twisting of the ice cube mold 100 to a level that frees previously formed ice cubes in the cavities 116. When the ice cube mold 100 reaches a sufficient angle of twist to effect full ice extraction, an element 128, such as a boss located on the ice cube mold 100, may activate a momentary switch by physical contact. The element 128 may be located at any point on the ice cube mold 100 where the deflection of the element 128 correlates to the overall twisting of the ice cube mold 100. For example, as shown in
Automatic ice makers do not typically include a feedback mechanism to control the amount of torque generated by the motor 102 for extracting ice cubes from the ice cube mold 100. Excess friction between one or more of the ice cubes and the cavities 116 in the ice cube mold 100 may prevent an ice cube from ejecting from the ice cube mold 100 without the addition of more force. Consequently, elements of the ice maker that are subject to the application of the additional force may experience fatigue and failure.
To provide feedback indicative of the level of force being applied to various elements of the ice maker, particularly to the elements actuated during an ice cube harvesting operation, a sensor 112 capable of outputting an electrical signal indicative of an applied mechanical force may be provided. Generally, sensors that convert mechanical force into electrical signals are known as electromechanical transducers. A force sensor for elements of an ice maker may be subject to large angles of deflection and high values of strain. Namely, a sufficient angle of twist for an ice cube mold to induce a level of torsion that will eject ice cubes typically ranges from 20 to 40 degrees. Due to these operating characteristics, a particularly relevant type of electromechanical transducer for use as a force sensor is a piezo dielectric elastomer (PDE).
PDEs are a type of dielectric electroactive polymer (DEP). Generally, DEPs are materials in which actuation is caused by electrostatic forces between two electrodes which squeeze the polymer. PDEs are capable of very high strains and are fundamentally a capacitor that changes capacitance when a voltage is applied by allowing the polymer to compress in thickness and expand in area in response to an electric field. DEPs require no power to keep the actuator at a given position. Because of the highly flexible nature of DEP, PDEs may be used as sensors for measuring an applied force in an environment where significant deformation may occur that would render conventional transducers inoperative.
With the use of PDE force sensors, the applied motor torque may be monitored and managed in a controlled fashion to aid in the ice harvesting process. As shown in
While the force sensor 112 as shown in
The ice cube mold 100 may be formed of any material that is both flexible and has a thermal conductivity conducive to forming ice. For example, aluminum has a thermal conductivity much higher than water and therefore aids in producing ice quickly. Other materials contemplated for the ice cube mold generally include plastics and metals. The material used for the ice cube mold and its corresponding properties may directly affect the preferred placement of the one or more force sensors. Other factors may include the shape and relative placement of the cavities of the ice cube mold 100.
Referring now to
As seen in
During an ice harvesting process with a rotating rake 200, a heating element connected to the ice cube mold 100 may apply heat to the cavities 116. Then, the rake 200 may rotate the fingers 212 through the briefly heated cavities 116 and effect removal of the ice cubes. Similar to the twisting of the ice cube mold 100, the process of rotating the fingers 212 of the rake 200 through the cavities 116 may apply an excessive level of force to the ice cubes causing either the ice cubes to break or elements of the rake 200 to fatigue. Additionally, undesirable levels of noise may occur during the ice harvesting process. By implementing a PDE force sensor 214 on the rake 200 in a manner similar to that described above for the ice cube mold 100, a controlled application of torque from the motor 102 to rotate the rake 200 may mitigate deleterious effects including broken ice, rake fatigue and excess noise.
For example, as shown in
As shown in
The base 320 of the ice storage bin 22 may be removably supported on an ice storage bin mounting plate 322. When attached to the ice storage bin mounting plate 322, the ice storage bin 22 is securely connected to the refrigerator 10. As best seen in
Provided on top of the protrusions 324 and, consequently, below the ice storage bin 22, one or more PDE force sensors 310 may detect the weight of the storage bin 22 including its content when it is placed on the ice storage bin mounting plate 322. The PDE force sensor 310 may experience a level of compression that correlates with the weight placed on it. In this way, the PDE force sensors 310 may output a signal that may be calibrated to indicate the weight of the ice cubes within the ice cube reservoir 316.
Typically, an ice storage bin 22 in a freezer compartment of a refrigerator 10 is designed to maximize the ice cube reservoir 316. That is, the storage bin 22 may assume the maximum dimensions of the space available in the freezer compartment and the ice harvesting process may be configured to produce ice until the ice cube reservoir 316 completely fills the storage bin 22. Consequently, for many consumers, the storage bin 22 may hold an undesirable amount of ice that may become stagnant and malodorous or may sublimate from unuse. To avoid the problem of ice staleness, it may be desirable to limit the amount of ice available based on an individual consumer's preference.
Therefore, to detect the level of ice storage, the controller 104 in communication with the PDE force sensor 310 may monitor the ice level by determining the weight of the ice storage bin 22 with ice cubes in the ice cube reservoir 316. In response to the determined level of ice based on the PDE force sensor output and a user-defined input stating a desired level of ice, the controller may prevent additional ice harvesting by the ice maker 16. The controller 104 may allow for continued ice harvesting once the level of ice storage falls below the consumer's desired level. For example, upon consumption of ice cubes, the PDE force sensor 310 may continue to output a signal to indicate the weight of the ice cubes. Once the weight falls below the value associated with the desired level of ice storage, the controller may signal the ice maker 16 to continue harvesting. Alternatively, the consumer may choose to increase the desired level of ice storage.
In addition to preventing an ice harvesting process when the ice reservoir 316 reaches a desired level of ice cubes, the ice making assembly may be designed to prevent ice harvesting when the storage bin 22 is removed from the refrigerator 10. As shown in
Depending upon the placement and configuration of the PDE sensor 310 and controller 104, it is contemplated that the PDE sensor 310 may be operated in a wireless configuration. While it is generally known to operate sensors with either a hard-wired or wireless connection, typical wireless sensors require external power sources that require additional wiring to power supplies. As previously described, PDE sensors 310 require very little power for operations. Additionally, PDE devices may be configured to generate power when exposed to mechanical vibrations. That is, PDE devices may scavenge energy from ambient vibrations. For refrigerators, sources of mechanical vibration may include a power cycle of the compressor, placement of the ice storage bin 22 onto the ice storage bin mounting bracket 322, the kinetic energy from harvested ice landing in the ice storage bin 22, the weight of products as they are placed on refrigerator shelves, etc. By either storing scavenged energy into a battery or using power on demand, the PDE sensor 310 may locally source power for operating a wireless connection to the controller 104. The PDE force sensor 310 and the energy scavenging PDE device may be the same device or may be implemented as separate devices. While operating one or more PDE sensors with a power scavenging PDE device may provide a desirable power saving feature, it is noted that a more typical wired connection to enable communication between the PDE sensor 310 and the controller 104 may be implemented.
While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the invention which is defined in the appended claims.
Claims
1. An ice making assembly comprising:
- an ice maker having an output for expelling ice cubes;
- a storage bin defining an ice cube reservoir and having an opening in communication with the ice maker output; and
- a weight sensor comprising a piezo dielectric elastomer (PDE) provided below the storage bin and outputting a signal indicative of the weight of the ice cubes within the reservoir;
- wherein ice cubes expelled from the ice maker are received through the opening and stored in the ice cube reservoir, with the weight sensor providing an output indicative of the weight of the ice cubes within the reservoir.
2. The ice making assembly of claim 1, wherein the ice maker is located higher than the storage bin.
3. The ice making assembly of claim 2, wherein the opening is in a top of the storage bin.
4. The ice making assembly of claim 3, wherein the output does not overlie the opening.
5. The ice making assembly of claim 1, wherein the weight sensor is attached to a storage bin mounting plate.
6. The ice making assembly of claim 5, wherein the storage bin is removable from the storage bin mounting plate.
7. The ice making assembly of claim 5, wherein the storage bin compresses the weight sensor when the storage bin is placed onto the storage bin mounting plate.
8. The ice making assembly of claim 1, wherein the ice maker expels ice cubes when the weight sensor output is within a pre-specified range.
9. The ice making assembly of claim 8, wherein the pre-specified range is based in part on a user input.
10. The ice making assembly of claim 9, wherein the user input selects an amount of ice available in the storage bin wherein a selected amount of ice is less than a maximum amount of ice that the storage bin will hold.
11. The ice making assembly of claim 1, wherein the ice maker expels ice cubes when the weight sensor output is below a pre-specified value.
12. The ice making assembly of claim 1, wherein the ice maker expels ice cubes when the weight sensor output is equal to or below a pre-specified value.
13. The ice making assembly of claim 1, wherein the ice maker expels ice cubes when the weight sensor output is above a pre-specified value.
14. The ice making assembly of claim 8, wherein the pre-specified range is based in part on a capacity of the storage bin.
Type: Application
Filed: Jan 5, 2018
Publication Date: May 10, 2018
Applicant: WHIRLPOOL CORPORATION (BENTON HARBOR, MI)
Inventors: ALBERTO R. GOMES (CUMMING, GA), YEN-HSI LIN (SAINT JOSEPH, MI), ANDREW M. TENBARGE (SAINT JOSEPH, MI)
Application Number: 15/862,680