Abstract:
A device for sensing a level of ice stored in a bin of an automatic ice maker includes a bail arm and an actuator mechanism. The actuator mechanism is constituted by a shape memory alloy that, upon application of a voltage, contracts to move the bail arm to a raised position prior to initiation of an ice harvest cycle. After completion of the ice harvest cycle, the voltage is discontinued, allowing the shape memory alloy to relax, causing the bail arm to return to a lowered position. The bail arm includes a sensing member that extends into the bin and, depending upon the level of ice, prevents the bail arm from contacting a sensing switch, temporarily halting ice production.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention pertains to the art of refrigerators and, more particularly, to a sensing device for detecting a level of ice present within an ice storage bin of an automatic ice maker system arranged within the refrigerator. 
   2. Discussion of the Prior Art 
   In the art of refrigerators, it is widely known to incorporate an automatic ice maker system wherein ice cubes are formed and collected within an ice storage bin. The ice cubes can either be accessed directly at the ice storage bin or through a dispenser. With such a system, provisions are commonly made to sense a level of ice cubes in the ice storage bin. A control is employed to automatically terminate the production of additional ice cubes when the amount of ice cubes in the storage bin reaches a predetermined level. Typically, the automatic ice maker will have an associated bail arm which rises and falls with the level of ice in the storage bin. When the level of ice causes the bail arm to shift upward a predetermined distance, the formation of additional ice is temporarily terminated. However, with this arrangement, often times ice can pile onto the bail arm in such a manner as to prevent the bail arm from shifting upward and terminating ice production. 
   To address this problem, some automatic ice makers are provided with a separate motor and cam arrangement, or utilize existing drive components, to raise the bail arm prior to an ice harvesting cycle. That is, prior to harvesting or ejecting ice cubes into the storage bin, the bail arm is raised so that ice cubes that are ejected into the bin do not pile onto or accumulate on the bail arm. However, while effective at preventing the bail arm from signaling a false negative, and allow ice to exceed preset levels, motor and cam arrangements increase the overall cost, complexity and size of the automatic ice makers. Additionally, the burden placed on existing drive components could detrimentally impact the service life of the ice maker. In the highly competitive field of kitchen appliances, it is advantageous to minimize manufacturing steps, eliminate potential failure points or otherwise increase the efficiency of an appliance without detracting from an overall established level of quality. 
   Based on the above, despite the existence of the automatic ice makers in the prior art, there still exists a need for an automatic ice maker system that includes a bail arm which is moved to a raised position prior to an ice harvesting cycle. More specifically, there exists a need for a bail arm that employs a simplified actuation mechanism to move the bail arm between the raised and lowered positions. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a device for sensing a level of ice cubes in a storage bin of an automatic ice maker. Specifically, the invention is directed to the actuation of a bail arm of the automatic ice maker. More specifically, prior to an ice harvesting cycle, the bail arm is automatically raised so that ice cubes, dropping into the storage bin, do not impede the movement of the bail arm. Other times, the bail arm simply rises and falls between a raised position, signaling the ice maker to terminate ice production, and a lowered position, signaling the ice maker to initiate or continue ice production. 
   In accordance with a preferred embodiment of the invention, the actuation of the bail arm is carried out by a shape memory alloy device (SMA) operatively connected to the bail arm. Prior to the ice harvest cycle, voltage is applied to the SMA causing the SMA device to contract and move the bail arm to the raised position. Once the bail arm is raised, the ice maker initiates the ice harvest cycle, dispensing ice cubes into the storage bin. At the completion of the ice harvest cycle, voltage is removed from the SMA device and the SMA device returns to a preset shape which allows the bail arm to return to the lowered position. If the bail arm is prevented from reaching a predetermined point, a signal is sent to the ice maker to terminate the production of ice. 
   In accordance with the most preferred embodiment of the invention, a sensing switch is operatively connected between the bail arm and the automatic ice maker. The sensing switch is positioned such that, when a level of ice in the storage bin reaches a predetermined point as determined by the position of the bail arm, ice production is terminated. The sensing switch includes a switch arm that, upon contact with the bail arm, triggers the sensing switch to signal the ice maker to resume ice production. That is, the switch arm is positioned so, when a level of ice in the storage bin is below the predetermined level, the bail arm will move further towards the lowered position, thereby contacting the switch arm and signaling a need for additional ice production. 
   Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a partial, perspective view of a refrigerator depicting an ice level sensing device constructed in accordance with the present invention arranged within an upper freezer compartment; 
       FIG. 2  is a side, elevational view of a bail arm of the automatic ice maker depicted in a raised position illustrating a shape memory alloy actuator portion of the ice level sensing device; 
       FIG. 3  is a side elevational view of the bail arm of  FIG. 2 , illustrating a sensing switch portion of the ice level sensing device; 
       FIG. 4  is a side elevational view of the bail arm depicted in a lowered position illustrating the shape memory alloy actuator portion of the ice level sensing device; and 
       FIG. 5  is a side elevational view of the bail arm of  FIG. 4 , illustrating the sensing switch portion of the ice level sensing device. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   With initial reference to  FIG. 1 , a refrigerator, generally indicated at  2 , includes a cabinet  4  having arranged therein a freezer compartment  8  which can be selectively accessed through the pivoting of a freezer door  10 . Also provided is a fresh food door  12  which enables access to a fresh food compartment (not separately labeled). As shown, refrigerator  2  constitutes a top mount style unit. However, as will become more fully evident below, the present invention is equally applicable to various other types of refrigerators, including side-by-side style units, bottom mount units and French door units. 
   Arranged within freezer compartment  8  is an ice maker assembly  16 . In a manner known in the art, ice maker assembly  16  includes a body portion  17  supporting a controller  18  that is mounted behind a cover  19 . Ice maker assembly  16  includes an ice maker unit  20  and an ice storage bin  22 . Ice maker unit  20  is also shown to include a bail arm  26  having a pair of fore-to-aft spaced and generally parallel leg portions  28  and  29  which are interconnected by a cross leg portion  31 . Additionally, ice maker assembly  16  includes a sensing member  33  pivotally connected to bail arm  26  so as to project into ice storage bin  22 . In the embodiment shown, sensing member  33  includes a pair of fore-to-aft spaced and generally parallel leg sections  34  and  35  which are interconnected by a cross leg section  36 . Leg portion  28  is shown to be operatively connected to a sensing switch  37  ( FIG. 3 ) which, in the embodiment shown, is depicted as a micro switch. Actually, leg portion  28  abuts a sensing arm portion  38  of sensing switch  37  which, as will be described more fully below, controls an ice production cycle of ice maker assembly  16 . Finally, ice maker unit  20  is shown to include an ice mold  40 . 
   In general, this construction, as well as the operation, of ice maker unit  20  is known in the art. Basically, a flow of water is directed to ice mold  40  to fill up various cavities (not separately labeled) thereof in order to produce ice cubes which are deposited into storage bin  22 . In a typical ice maker arrangement, once storage bin  22  has collected a sufficient amount of ice cubes, the ice cubes will act on bail arm  26  causing bail arm  26  to move from a lowered position to a raised position which, in turn, operates on sensing arm  38  to de-activate ice maker unit  20 . Bail arm  26  and/or sensing arm  38  are preferably biased downward such that, when the level of ice cubes in storage bin  22  reaches a predetermined lower limit, ice maker unit  20  is automatically reactivated to restart the ice production cycle. 
   As best shown in  FIGS. 2-4 , body portion  17  includes a support member  47  having a support wall  49 . Support wall  49  includes a first support surface  52  and an opposing second, support surface  53 . Support wall  49  extends generally perpendicularly from a base portion  54 . In accordance with a preferred form of the invention, body portion  17  also includes an actuator mechanism  56  mounted on first support surface  52 . Actuator mechanism  56  is operatively connected to bail arm  26  and, as will be discussed more fully below, controller  18 . As best shown in  FIG. 3 , sensing switch  37  is mounted to second support surface  53  of support member  47 , with sensing arm  38  projecting outward at an angle towards leg portion  28 . 
   In accordance with the most preferred form of the invention, actuator mechanism  56  includes a linkage assembly  64 . As best shown in  FIGS. 2 and 4 , linkage assembly  64  includes a first member  67  having a fixed end portion  68  that extends to a pivoting end portion  69 . Pivoting end portion  69  is linked to a second member  71  having a first end  73  that extends to a second end  74  through a connecting portion  75 . Connecting portion  75  is pivotally secured to an end portion (not separately labeled) of leg portion  28 . With this arrangement, a downward force acting on first member  67  will cause bail arm  26  to shift to a raised position as represented in  FIGS. 2 and 3 . After the force being applied to first member  67  is removed, bail arm  26  will return, under the force of gravity, to the lowered position as represented in  FIGS. 4 and 5 . 
   In further accordance with the most preferred form of the present invention, the force acting on first member  67  is provided by a shape memory alloy (SMA) device or actuator  84 . As best shown in  FIGS. 2  and  4 , SMA device  84  is constituted by a Nitenol wire having a first end  86  extending to a second end  87  through an intermediate portion  89 . At this point, it should be understood that, while Nitenol is employed as the preferred SMA device, other alloys, having substantially similar properties, are acceptable. In any event, intermediate portion  89  of SMA device  84  extends over a pin  94  provided on first member  67 . 
   With this arrangement, prior to initiating an ice harvesting cycle, controller  18  activates a power source  100  coupled to first end  86  and second end  87  to supply a voltage to SMA device  84 . The voltage causes SMA device  84  to contract, applying a downward force upon first member  67  through pin  94 . The downward force applied to first member  67  causes bail arm  26  to move to the raised position as represented in  FIG. 3 . In the fully raised position, any ice that is released from ice mold  40  will not fall onto sensing member  33 . That is, upon completion of an ice production cycle, controller  18  directs ice maker unit  20  to expel ice cubes into ice storage bin  22 . If sensing member  33  remains within ice storage bin  22  during this cycle, ice cubes could, ultimately, accumulate on cross leg section  36  causing a failure in the overall operation of ice maker assembly  16 . Thereby, prior to ejecting ice into storage bin  22 , bail arm  26  is moved to the fully raised position. In any case, once the ice harvesting cycle has completed, controller  18  terminates the applied voltage across first and second ends  86  and  87 , allowing the SMA device  84  to release and enabling bail arm  26  to return, under the force of gravity, to the lowered position. 
   In the event that the ice cubes have not reached a predetermined level in ice bin  22 , cross leg section  36  of sensing member  33  will extend into ice storage bin  22  to a point where leg portion  28  contacts sensing arm  38  to signal a need for additional ice. Thus, ice maker assembly  16  will initiate another ice production cycle. In contrast, in the event that the ice cubes accumulated within ice storage bin  22  have reached the predetermined level, sensing member  33  will contact the ice cubes and prevent leg portion  28  from coming into contact with sensing arm  38 , thereby signaling that no additional ice is needed. At this time, controller  18  terminates, at least temporarily, ice production. That is, ice production is terminated until leg portion  28  once again contacts sensing arm  38  to signal that more ice is needed. In any event, it should be understood that SMA device  84  provides a simple and cost effective means of actuating bail arm  26  prior to an ice harvesting cycle so as to increase an overall efficiency and ease of manufacture of ice maker assembly  16 . 
   Although described with reference to a preferred embodiment of the present invention, it should be readily apparent to one of ordinary skill in the art that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, the bail arm could simply be formed as a single member provided with a pivoting sensing arm. Also the control portion assembly could be mounted in various fashions, such as on a shelf in the freezer compartment with the bail arm extending into a door mounted in the storage bin. In general, the invention is only intended to be limited to the scope of the following claims.