Method and apparatus for deterring theft of manually operated wheeled vehicles

An anti-theft apparatus for inhibiting the unauthorized use and removal of a shopping cart from a designated use area, comprising:

• a wheel;
• a rotation-inhibiting means in association with said wheel, said rotation-inhibiting means including a rigid locking member movable between an unlocked position and a locked position in which it immobilizes said wheel against movement;
• a counting means;
• means for detecting passages of said shopping cart past a predetermined reference point and operative to set and reset said counting means, said predetermined reference point being identified by means generating a first magnetic field oscillating at a first frequency and a second magnetic field oscillating at a second frequency, said detecting means including a first tuned coil responsive to said first magnetic field and operative to set said counting means, and a second tuned coil responsive to said second frequency and operative to reset said counting means;
• a sensor means for sensing rotation of said wheel and for generating an output which can be counted by said counting means;
• and
• a means activated by said counting means and operative to actuate said rotation-inhibiting means after a predetermined count has been reached by said counter after it has been set.