Aerosol Generating Devices

Abstract

An aerosol generating device includes sensing means for detecting when an aerosol generating article is inserted into or withdrawn from a heating chamber of the device. A roller is mounted for rotation about a roller axis such that an article moving along a pre-defined insertion path engages a surface of the roller and causes it to rotate. The sensing means determines a direction of rotation of the roller. The sensing means may be responsive to a property of the roller, such as its radius or a magnetic field. The property may vary with angle about the roller axis to define one or more indexes that can be detected by one or more sensors disposed adjacent to the roller.

1 . An aerosol generating device comprising:
 a heating chamber configured for receiving an aerosol generating article that may be inserted into the heating chamber along a pre-defined insertion path or withdrawn from the heating chamber along the same insertion path;   a roller mounted for rotation about a roller axis that is generally-substantially perpendicular to the insertion path, wherein when an aerosol generating article moves along the insertion path, the aerosol generating article engages a surface of the roller, thereby causing the roller to rotate; and   sensing means for determining a direction of rotation of the roller.   
     
     
         2 . The aerosol generating device according to  claim 1 , wherein:
 the roller comprises a property that varies with angle about the roller axis; and   the sensing means comprises at least one sensor configured to measure a variation in the property as the roller rotates past the at least one sensor to determine the direction of rotation of the roller.   
     
     
         3 . The aerosol generating device according to  claim 2 , wherein:
 the variation in the property of the roller with angle about the roller axis defines an index at an index angular position on the roller;   the at least one sensor comprises a first sensor capable of configured to detecting movement of the index past a first sensor angular position about the roller axis and a second sensor configured to detecting movement of the index past a second sensor angular position about the roller axis; and   an angle between the first and second sensor angular positions is less than 180°.   
     
     
         4 . The aerosol generating device according to  claim 3 , wherein the sensing means further comprises:
 a timer for measuring, as the roller rotates,   a first time interval from when the first sensor detects movement of the index past the first sensor angular position to when the second sensor detects movement of the index past the second sensor angular position, and   a second time interval from when the second sensor detects movement of the index past the second sensor angular position to when the first sensor detects movement of the index past the first sensor angular position; and   a comparator for comparing the first interval with the second interval to determine the direction of rotation of the roller.   
     
     
         5 . The aerosol generating device according to  claim 3 , wherein the sensing means further comprises:
 a third sensor configured to detecting movement of the index past a third sensor angular position about the roller axis; and   a timer for measuring, as the roller rotates,
 a first time when the first sensor detects movement of the index past the first sensor angular position, 
 a second time when the second sensor detects movement of the index past the second sensor angular position, and 
 a third time when the third sensor detects movement of the index past the third sensor angular position; and 
   a comparator for determining the direction of rotation of the roller from the order in which the first time, the second time and the third time occur.   
     
     
         6 . The aerosol generating device according to  claim 2 , wherein:
 the property of the roller varies with angle about the roller axis in a pattern that is not mirror-symmetric.   
     
     
         7 . The aerosol generating device according to  claim 6 , wherein:
 the variation of the property of the roller with angle about the roller axis defines a first index at a first index angular position on the roller and a second index at a second index angular position on the roller;   the at least one sensor is configured to distinguish between the first and second indexes; and   an angle between the first and second index angular positions is less than 180°.   
     
     
         8 . The aerosol generating device according to  claim 6 , wherein:
 the variation of the property of the roller with angle about the roller axis defines first, second and third indexes respectively at first, second and third index angular positions on the roller; and   angles between the first, second and third index angular positions are all different.   
     
     
         9 . he aerosol generating device according to  claim 2 , wherein:
 the property that varies with angle about the roller axis is a magnetic property; and   the at least one sensor is capable of configured to detecting changes in a magnetic field as the roller rotates past the at least one sensor.   
     
     
         10 . The aerosol generating device according to  claim 9 , wherein the roller comprises one or more permanent magnets arranged to create the magnetic property that varies with angle about the roller axis. 
     
     
         11 . The aerosol generating device according to  claim 2 , wherein the property that varies with angle about the roller axis is a radius of the roller; and
 wherein the at least one sensor is configured to detecting changes in the radius of the roller as the roller rotates past the at least one sensor.   
     
     
         12 . The aerosol generating device according to  claim 11 , wherein the at least one sensor comprises a sensor element that engages the surface of the roller and moves towards and away from the roller axis in response to changes in the radius of the roller as the roller rotates. 
     
     
         13 . The aerosol generating device according to  claim 12 , wherein the at least one sensor further comprises an electrical switch, which is toggled between ON and OFF conditions as the sensor element moves towards and away from the roller axis. 
     
     
         14 . The aerosol generating device according to  claim 1 , further comprising:
 a heater for heating an aerosol generating article received in the heating chamber;   a counter for counting revolutions of the roller; and   a controller for activating the heater when the counter has counted a predetermined number of revolutions.   
     
     
         15 . A method of determining when an aerosol generating article is inserted into or withdrawn from a heating chamber of an aerosol generating device, the method comprising:
 moving an aerosol generating article along a pre-defined insertion path to or from the heating chamber;   engaging the aerosol generating article with a surface of a roller that is mounted for rotation about a roller axis that is substantially perpendicular to the insertion path, thereby causing the roller to rotate; and   using sensing means to determine a direction of rotation of the roller.   
     
     
         16 . The method according to  claim 15 , wherein the sensing means comprises at least one sensor. 
     
     
         17 . An aerosol generating device comprising:
 a heating chamber configured for receiving an aerosol generating article inserted into the heating chamber along a pre-defined insertion path or withdrawn from the heating chamber along the same insertion path;   a roller mounted for rotation about a roller axis that is substantially perpendicular to the insertion path, wherein when an aerosol generating article moves along the insertion path, the aerosol generating article engages a surface of the roller, thereby causing the roller to rotate; and   at least one sensor for determining a direction of rotation of the roller.