Patent ID: 7255246

Claim:
A vending machine comprising: a cabinet frame including top, bottom, side and rear walls that collectively define a central cavity; a plurality of column walls defining a plurality of stack areas for receiving product containers to be selectively dispensed from the vending machine; a door pivotally mounted to the cabinet frame, said door adapted to selectively close the central cavity; a delivery chute for receiving a product container dispensed from the vending machine; a vend motor for selectively delivering one of the plurality of containers from one of the plurality of columns to the delivery chute; a control unit for selectively activating the vend motor for a vend operation, said control unit including a sensor electronic control board having an amplitude detector and a phase detector; and a vend sensor electrically connected to the control unit, said vend sensor including first and second sound elements mounted in the container delivery chute between which pass a sound beam wherein, during the vend operation, one of the plurality of product containers passes between the first and second sound elements and disrupts the sound beam which is signaled to the control unit, said control unit processing a signal from the vend sensor and detecting a change in the sound beam to complete the vend operation.