Food processing apparatus including magnetic drive

#This invention relates to a magnetic drive to transmit rotational motion from a motive source into an enclosed space without a direct mechanical connection. More specifically, it relates to blenders, mixers, and like machines, and particularly to devices having a stirrer, impeller, blade, or other tool mounted within a removable cup or container, and rotated by means of a motor located in the stationary base of the machine.

#Conventional home blenders and mixers incorporate a mechanically-driven impeller rotatably mounted within a removable blender cup. The base of the cup incorporates a generally circular connection plate with a pattern of projections and/or depressions formed on its lower face that is removably mateable, using a vertical, drop-in movement, with a corresponding pattern formed on a like plate attached to the shaft of a motor housed in a base of the machine. This mechanical coupling between the blender cup and the blender motor requires a rotary seal at the base of the cup between the impeller and connecting plate. This seal is subject to considerable wear and tear over time, as is the mechanical coupling. Because seal failure can result in liquid leaking out of the cup, the seal and bearings in the base of the cup are built to ensure sealing at the expense of friction. The friction produces wear, heat, and loss of power. Moreover, the conventional blender produces much unwanted noise, and the mechanical interlocking coupling between the plates can make it awkward or difficult to remove the cup from, and return the cup to, the base.

#Many drink mixers have the drive motor mounted in the base directly under the cup. If overall height is a concern, however, the motor may be positioned off to the side and coupled to the driving shaft by a belt or gear arrangement.

#These and other features and objects of the invention will be more fully understood from the following detailed description that should be read in light of the accompanying drawings. In the accompanying drawings, like reference numerals refer to like parts throughout the different views. While the drawings illustrate principles of the invention disclosed herein, they are not drawn to scale, but show only relative dimensions.

#FIG. 1 is a view in perspective of a blender/shaver machine constructed according to the present invention;

#FIG. 2 is a view in vertical section of the blender/shaver machine of FIG. 1;

#Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the food processing apparati and magnetic drives disclosed herein. One or more examples of these embodiments are illustrated in the drawings. Those of ordinary skill in the art will understand that the food processing apparati and magnetic drives disclosed herein can be adapted and modified to provide instruments and methods for other applications and that other additions and modifications can be made without departing from the scope of the present disclosure. For example, the features illustrated or described as part of one embodiment or one drawing can be used on another embodiment or another drawing to yield yet another embodiment. Such modifications and variations are intended to be included within the scope of the present disclosure.

#FIGS. 1 and 2 show a principal application of the present invention, namely, in a blender/shaver machine 10 adapted to the automatic manufacture of frozen drinks in bars and restaurants. A supply of ice in a hopper 12 is fed by a rotating set of blades 14 to a blade 16. The shaved ice falls through a chute 18 including a lid 20 into a blender cup 22 to which liquid ingredients such as a flavor concentrate and/or spirit have been added. Rotation of an impeller (or blade set) 24 at the bottom of the cup for a preset period of time produces a high quality frozen drink—one that peaks when poured and has a generally uniform, non-marbled, non-watery consistency. While the invention will be described below principally with reference to use in the blender/shaver 20, it will be understood that the invention can be used in a wide variety of applications where it is desired to transmit power from a rotary output of a motive source (e.g., a motor) to a driven member under a load, particularly a rotating driven member held in a container that is sealed from and removable from the motive source. The invention can be used, for example, in a variety of food processing equipment such as home blenders, food mixers, food processors and juicers.

#A magnetic drive 26 for the impeller 24 is the focus of the present invention. With reference to FIGS. 3-5, the drive 26 includes a generally circular drive plate 34 rotatably mounted in the base 22a of the blender cup 22 and a brushless d.c. motor 28 including stator coils 30 and a rotor 32. The rotor in turn includes a double magnet assembly 35 preferably formed of a rotor ring magnet 36, a drive ring magnet 38 and a disc 40 of a magnetizable material, preferably cold-rolled steel, bonded between the magnets 36 and 38.