Patent ID: 8490903

Claim:
A thickness detecting system for a paper shredder, comprising: a first sensor positioned in a throat of the paper shredder and configured to output a signal when shredding material is inserted into the throat; a lever arm extending into the throat, the lever arm configured to rotate about an axis responsive to contact with shredding media; a spring coupled to the lever arm and configured to provide resistance to the lever arm's rotation; a removable counterweight coupled to the lever arm and configured to dampen the lever arm's rotation; a second sensor configured to output a signal when the lever arm rotates to a first position, a third sensor configured to output a signal when the lever arm rotates to a second position; wherein circuitry is coupled to the first sensor, second sensor, third sensor, and a motor coupled to cutting blades and the circuitry is configured to control the operation of the motor responsive to receiving signals from the first sensor, second sensor, and/or third sensor.