Patent Publication Number: US-RE33612-E

Title: Ice maker system

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an ice maker system for refrigerators and more particularly to such a system wherein a harvest rake is driven at a variable speed. 
     Ice maker systems have been used in refrigerators for many years. In such systems, a timing mechanism and a harvest rake are driven by a motor. The timing mechanism controls the on-off time of the system, heat to the system and other related functions while the harvest rake is rotated to remove ice from the ice maker. 
     In accordance with the present invention, a variable speed is imparted to the harvest rake such that a slower speed is applied during ice removal and higher speed during liquid filling of the ice maker. This provides a higher torque to the rake during ice removal and a faster more accurate timing during filling. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention relates to a timed drive means for an ice making system which comprises cam means and switch means operated by the cam means, a motor, and coupling means coupling the motor to the cam means to operate same, including a pair of meshing gears at least one of which is non-circular, the meshing gears programmed to apply a first speed to the cam means during ice removal and a second faster speed during liquid filling of the ice making system. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded, schematic view of an ice making system. 
     FIGS. 2 and 3 are schematics showing two operating modes. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawing, there is shown an ice maker system 10 employing the features of the invention. The ice maker system includes a motor 12 which drives a timing mechanism 14, a harvest rake 16, and a liquid receptacle 18. Motor 12 may be of the synchronous type and may include a gear train to provide a desired gear reduction. Timing mechanism 14 includes a cam means 20 which includes a series of cams 22 carried on a camshaft 24, and switch means 26. Switch means 26 includes a series of upper and lower electrical contact blades 28 and 30, one of which engages the cams. Rotation of the cams causes the cams to open and close electrical contacts 28&#39; and 30&#39;. The opening and closing of the electrical contacts opens and closes electrical circuits to control such functions as turning motor 12 on and off, controlling a thermostat, etc. in a manner well known in the art. Harvest rake 16 includes a rod 34 and teeth 36 extending from the rod. The rod can be connected to camshaft 24 by some suitable means or alternatively shaft 24 and the rod could be of a one piece construction. Thus the harvest rake rotates with camshaft 24. 
     In accordance with the present invention, a variable speed is imparted to harvest rake 16. This is accomplished through coupling means 40 which couples motor 12 to camshaft 24. Coupling means 40 includes a motor output shaft 42 and a pair of meshing gears 44 and 46. Gear 44 is fixedly carried on shaft 42 to be rotated therewith. Gear 46 is fixedly carried on camshaft 24 such that the camshaft is rotated in accordance with the gear. As shown, each of the gears 44 and 46 are non-circular. In the present embodiment, each of the gears are elliptical with their centers of rotation being at one of the foci 44&#39;, 46&#39; of their respective ellipse. The gears are programmed with respect to each other such that a slower camshaft speed of rotation is generated when harvest rake 16 is removing ice from the receptacle. 
     Referring to FIG. 2, the operating mode of the gears are shown when rake 16 is in the position when receptacle 18 is being filled with liquid. The gears are shown at the position at or near the fastest speed being applied to the rake. As shown, foci 44&#39; is at its furthest point from the area A where the gears mesh while foci 46&#39; is at its closest point to area A. 
     In FIG. 3, the operating mode of the gears are shown when rake 16 is removing ice from receptacle 18. The gears are shown at or near the position of slowest speed with highest torque being applied to the rake. As shown, foci 44&#39; is at its closest point to gear meshing area B while foci 46&#39; is at its furthest point from gear meshing area B. 
     Actual filling and removal may occur at positions slightly removed from the positions shown in FIGS. 2 and 3, however, the benefits of the gearing system are still realized.