Ultrasonic sensor for detecting the dispensing of a product

Abstract

A vending machine includes a vend sensor for detecting a completion of a vend operation. The vend sensor includes an electronic circuit connected to first and second sound elements positioned on opposing sides of a product delivery chute of the vending machine. The first sound element directs a sound beam across the product delivery chute where it is received by the second sound element. During a vend operation, a product container is guided to the product delivery chute to be dispensed to a consumer. As the container passes through the product delivery chute, the sound beam is interrupted, thereby signaling the completion of a vend operation. Each of the first and second sound elements is provided with a cone that focuses the sound beam so as to limit interruptions stemming from outside sound sources.

1 . A vending machine comprising:
 a cabinet frame including top, bottom, side and rear walls that collectively define a central cavity;   a plurality of product dispensers within the central cavity each holding a plurality of products to be selectively dispensed from the vending machine;   a door pivotally mounted to the cabinet frame, the door adapted to selectively close the central cavity;   a delivery chute for receiving a product dispensed from a product dispenser within the vending machine;   a vend motor for selectively delivering one of the plurality of products from one of the product dispensers to the delivery chute;   a control unit for selectively activating the vend motor for a vend operation; and   a vend sensor electrically connected to the control unit, the vend sensor including first and second sound elements mounted in the delivery chute between which pass a sound beam, wherein, during the vend operation, a dispensed one of the plurality of products passes between the first and second sound elements and disrupts the sound beam, wherein the vend sensor transmits a completion signal to the control unit to complete the vend operation in response to passage of the dispensed product.   
     
     
         2 - 23 . (canceled) 
     
     
         24 . The vending machine according to  claim 1 , wherein the first sound element is a speaker and the second sound element is a microphone. 
     
     
         25 . The vending machine according to  claim 24 , wherein the speaker emits the sound beam, the sound beam having an ultrasonic wavelength. 
     
     
         26 . The vending machine according to  claim 25 , wherein the ultrasonic wavelength has a center frequency of approximately 40 KHz. 
     
     
         27 . The vending machine according to  claim 1 , wherein the vend sensor further comprises signal processing circuitry configured to determine a period, if any, and an amplitude of a portion of the sound beam received by the vend sensor. 
     
     
         28 . The vending machine according to  claim 27 , wherein the signal processing circuitry, in response to detecting that the portion of the sound beam received by the vend sensor is not periodic, initiates generation of the completion signal. 
     
     
         29 . The vending machine according to  claim 27 , wherein the signal processing circuitry detects distortion in the portion of the sound beam received by the vend sensor due to a product passing near, but not through, the sound beam. 
     
     
         30 . The vending machine according to  claim 27 , wherein the signal processing circuitry, in response to detecting that an amplitude of the portion of the sound beam received by the vend sensor is below a predetermined threshold, initiates generation of the completion signal. 
     
     
         31 . The vending machine according to  claim 1 , wherein the vend sensor detects disruption of the sound beam when no vend operation is being performed, and signals a main control unit in response to detecting disruption of the sound beam when no vend operation is being performed. 
     
     
         32 . A method of detecting product delivery within a vending machine formed by a cabinet frame including top, bottom, side and rear walls that collectively define a central cavity, a plurality of product dispensers within the central cavity each holding a plurality of products to be selectively dispensed from the vending machine, a door pivotally mounted to the cabinet frame, the door adapted to selectively close the central cavity, and a delivery chute for receiving a product dispensed from a product dispenser within the vending machine, the method comprising:
 selectively activating a vend motor for a vend operation delivering one of the plurality of products from one of the product dispensers to the delivery chute;   during the vend operation, detecting passage of the dispensed product between first and second sound elements mounted in the delivery chute between which pass a sound beam, passage of the dispensed one of the plurality of products disrupting the sound beam; and   transmitting a completion signal to a control unit within the vending machine controller activation of the product dispensers to complete the vend operation in response to passage of the dispensed product.   
     
     
         33 . The method according to  claim 32 , wherein the first sound element is a speaker and the second sound element is a microphone. 
     
     
         34 . The method according to  claim 33 , wherein the speaker emits the sound beam, the sound beam having an ultrasonic wavelength. 
     
     
         35 . The method according to  claim 34 , wherein the ultrasonic wavelength has a center frequency of approximately 40 KHz. 
     
     
         36 . The method according to  claim 32 , further comprising determining a period, if any, and an amplitude of a portion of the sound beam received by the vend sensor. 
     
     
         37 . The method according to  claim 36 , further comprising, in response to detecting that the portion of the sound beam received by the vend sensor is not periodic, initiating generation of the completion signal. 
     
     
         38 . The method according to  claim 37 , further comprising detecting distortion in the portion of the sound beam received by the vend sensor due to a product passing near, but not through, the sound beam. 
     
     
         39 . The method according to  claim 37 , further comprising, in response to detecting that an amplitude of the portion of the sound beam received by the vend sensor is below a predetermined threshold, initiating generation of the completion signal. 
     
     
         40 . The method according to  claim 32 , further comprising detecting disruption of the sound beam when no vend operation is being performed, and signaling a main control unit in response to detecting disruption of the sound beam when no vend operation is being performed.