Impeller driven metering assembly for a powder dispenser

Abstract

A metering assembly for use with a powder dispenser includes a reservoir subassembly including a bowl for holding a quantity of powder and having a slot extending from an interior portion of the bowl to an exterior portion of the bowl. A door plate is disposed adjacent the bowl and rotatable about an axis between an opened position and a closed position. The door plate generally includes a bore formed on the door plate, the bore selectively alignable with the slot to form a through-passage in the opened position and misaligned with the slot in the closed position, and an abutment adjacent the bore. An impeller is disposed within the bowl and configured to rotate about the axis and engage the abutment to transition the door plate between the opened position and the closed position.

1 . A metering assembly for use with a powder dispenser, the metering assembly comprising:
 a reservoir subassembly including a bowl for holding a quantity of powder and having a slot extending from an interior portion of the bowl to an exterior portion of the bowl;   a door plate disposed adjacent the bowl and rotatable about an axis between an opened position and a closed position, the door plate comprising:
 a bore formed on the door plate, the bore selectively alignable with the slot to form a through-passage in the opened position and misaligned with the slot in the closed position, and 
 an abutment adjacent the bore; and 
   an impeller disposed within the bowl and configured to rotate about the axis and engage the abutment to transition the door plate between the opened position and the closed position.   
     
     
         2 . The metering assembly of  claim 1  further comprising a key extending from the door plate, wherein the key engages the bowl to limit rotation of the door plate between the opened position and the closed position. 
     
     
         3 . The metering assembly of  claim 1 , further comprising a motor configured to induce rotation of the door plate. 
     
     
         4 . The metering assembly of  claim 3 , wherein the motor is a bidirectional motor that selectively rotates in a first direction or a second direction. 
     
     
         5 . The metering assembly of  claim 4 , wherein, when the motor rotates in the first direction, the door plate rotates from the closed position to the opened position, and wherein, when the motor rotates in the second direction, the door plate rotates from the opened position to the closed position. 
     
     
         6 . The metering assembly of  claim 2 , wherein the key engages the bowl adjacent the opening to limit rotation of the door plate between the opened position and the closed position. 
     
     
         7 . The metering assembly of  claim 1 , wherein rotation of the plate is limited to between 5° and 30° of rotation about the axis. 
     
     
         8 . The metering assembly of  claim 1 , wherein a number of rotations of the impeller determines a dispensed volume of powder. 
     
     
         9 . A metering assembly for use with a powder dispenser, the metering assembly comprising:
 a reservoir subassembly including a bowl for holding a quantity of powder, the bowl comprising:
 a slot that extends from an interior portion of the bowl to an exterior portion of the bowl, and 
 an abutment adjacent the slot; 
   a door arm mounted for rotation about an axis between an opened position and a closed position, the door arm comprising a first leg including a planar surface conforming to a base of the bowl and a bore formed on a portion of the planar surface, wherein the bore is alignable with the slot in the opened position and the planar surface covering the slot in the closed position, and   an impeller configured to rotate within the bowl and direct powder toward the slot.   
     
     
         10 . The metering assembly of  claim 9  further comprising a door arm motor assembly including a cam with a pin and the door arm including a second leg with a slot, the pin of the door arm motor being received within the slot of the second leg to rotate the door arm between the opened position and the closed position. 
     
     
         11 . The metering assembly of  claim 9 , further comprising a motor configured to induce rotation of the impeller. 
     
     
         12 . The metering assembly of  claim 11 , wherein the impeller comprises a plurality of blades. 
     
     
         13 . The metering assembly of  claim 12 , wherein each blade of the plurality of blades comprises:
 a sweep arm; and   a broom, wherein the broom maintains contact with the base of the bowl and deflects over the abutment.   
     
     
         14 . The metering assembly of  claim 11 , wherein a longitudinal axis of the slot is angularly offset relative to the blades. 
     
     
         15 . The metering assembly of  claim 9 , wherein rotation of the door arm is limited to between 5° and 30° of rotation about the axis. 
     
     
         16 . The metering assembly of  claim 9 , wherein a number of rotations of the impeller determines a dispensed volume of powder. 
     
     
         17 . A metering assembly for use with a powder dispenser, the metering assembly comprising:
 a reservoir subassembly including a bowl for holding a quantity of powder, the bowl comprising:
 a slot that extends from an interior portion of the bowl an exterior portion of the bowl, and 
 an abutment adjacent the slot; 
   a door arm mounted for rotation about an axis between an opened position and a closed position, the door arm comprising:
 a first leg including a planar surface conforming to a base of the bowl and a bore formed on a portion of the planar surface, wherein the bore is alignable with the slot in the opened position and the planar surface covering the slot in the closed position, and 
 a second leg including a slot; 
   an impeller configured to rotate within the bowl and direct a powder toward the slot; and   a sensor configured to detect an amount of powder dispensed through the bore and the slot.   
     
     
         18 . The metering assembly of  claim 17 , wherein the impeller comprises a plurality of blades. 
     
     
         19 . The metering assembly of  claim 18 , wherein each blade of the plurality of blades comprises:
 a sweep arm; and   a broom, wherein the broom maintains contact with the base of the bowl and deflects over the abutment.   
     
     
         20 . The metering assembly of  claim 17 , wherein a longitudinal axis of the slot is angularly offset relative to the blades to shear the powder along the abutment.