| 摘要 |
A display unit for point of sale advertising comprises a stationary object, such as a real or simulated flowering plant, mounted on a support, such as a flowerpot, and a flying object, such as a simulated butterfly, operated by driving apparatus so as to move in a randomly undulating and randomly reversible orbit around the plant, as would a real butterfly. The driving apparatus comprises an electric motor having a motor housing stationarily mounted on the flowerpot, a stator including a stationary field coil electrically energizable by alternating current mounted in the motor housing, and a rotor in the form of a bipolar permanent magnet rotatably mounted on an upright magnetizable metal shaft on the motor housing. The driving apparatus further comprises a thin resiliently flexible length of piano wire having its lower end mechanically connected to and rotatable by the permanent magnet rotor and having the simulated butterfly mechanically connected to its upper end. In operation, energization of the field coil produces a magnetic field which causes the permanent magnet rotor, the wire and the simulated butterfly to rotate in one direction. However, a predetermined mechanical load imposed on the permanent magnet rotor effected by random striking of the simulated butterfly against the plant, or by random horizontal and vertical excursions of the simulated butterfly in its orbital path, or by random "hand-up" of the permanent magnet rotor on its shaft, causes the rotor to periodically and frequently reverse its direction of rotation. The resultant effect is to cause the simulated butterfly to flutter about the flowering plant as would a real butterfly.
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