Readily installed food processor cutter tool with negative blade lift

In a rotary food processing apparatus having an upright working bowl with a vertical motor-driven shaft extending up into the bowl with its axis of rotation extending along the central axis of the bowl and in which a rotatable tool has a hub removably engaging down upon said drive shaft by a straight-line manual manipulation in driving relationship with the shaft provided with axially extending driving coupling means and such tool has a plurality of thin rigid cutter blades secured to said hub and extending outwardly therefrom, a lower one of said blades normally being positioned near the bottom of said vessel along the length of said blade with a small spacing between the bottom of said vessel and said lower blade, and said lower blade extending out to a diameter close to the full diameter of said bottom for permitting the operation of the apparatus with very small amounts of food, and a second one of said blades being positioned at a higher elevation on said hub, said lower blade having a swept back shape with its outer end trailing behind its inner portion, the improvement comprising:

• means for preventing said lower blade from dynamically climbing upwardly through pulverulent food material being processed for preventing said hub from being lifted upwardly relative to said drive shaft,
• said means including a downward inclination in the forward direction of rotation of the outer portion of said lower blade for developing a downward thrust on said lower blade as the outer portion of said lower blade revolves and moves at relatively high velocity through the food material in said working bowl,
• said lower blade having a sharp leading edge which sweeps rearwardly toward its outer tip,
• said outer tip being bent upwardly into a negative angle of attack, relative to the inner portion of the blade, and
• the inner portion of said sharp leading edge being positioned close to the bottom of said vessel.

For use in rotary food processing apparatus having an upright working bowl with a vertical motor-driven shaft extending up into the bowl with its axis of rotation extending along the central axis of the bowl and in which a rotatable cutter tool has an easily installed hub removably engaging down by a straight-line manual manipulation in driving relationship with the shaft provided with axially extending driving coupling means and such tool has a plurality of thin rigid cutter blades secured to said hub and extending therefrom, a lower one of said blades normally being positioned near the bottom of said vessel, and said lower blade extending out to an outer tip positioned close to the side wall of said vessel and a second one of said blades being positioned at a higher elevation on said hub, an improved rotary cutter tool with such easily installed hub in which:

• the inner portion of said lower blade near said hub is approximately horizontal and the outer portion thereof near said tip is bent upwardly relative to the inner portion along an inflection bend forming a downward inclination in the forward direction of rotation in the outer portion thereof near said tip for providing a negative angle of attack for developing a downward thrust on said outer portion of the lower blade as said outer portion revolves at relatively high velocity through food material in said working bowl near said side wall,
• whereby said rotary cutter tool is prevented from dynamically climbing upwardly through food material being processed to prevent the easily installed hub of said tool from being lifted upwardly relative to the drive shaft.

In rotary food processing apparatus having an upright working bowl with a vertical motor-driven shaft extending up into the bowl with its axis of rotation extending along the central axis of the bowl and in which a rotatable food processor tool has an easily installed hub removably engaging down by a straight-line manual manipulation in driving relationship with the shaft which is provided with straight axially extending driving coupling means and such tool has a plurality of rigid blades secured to said hub and extending therefrom, a lower one of said blades normally being positioned near the bottom of said vessel and extending out to an outer tip, and a second one of said blades being positioned at a higher elevation on said hub,

• an improved rotary food processor tool which is at all times freely removable from said drive shaft by lifting said hub vertically straight upwardly along said straight axially extending driving coupling means,
• said improved tool having means for preventing the freely removable hub of said rotary tool from inadvertently sliding upwardly along said straight axially extending driving coupling means of the drive shaft during food processing operation by preventing said lower blade from dynamically climbing upwardly through food material being processed,
• said preventing means including a major inner portion of the radial extent of the lower surface of the lower blade being substantially parallel with the bottom of said vessel, and
• an outer portion of said lower blade being inclined downwardly in the forward direction for developing a downward thrust on said outer portion of the lower blade as said outer portion revolves at relatively high velocity through food material in said working bowl.