| 摘要 |
<p>Fleas are repelled from a four-legged animal (1) by compressional waves derived from an electric-compressional wave transducer (15) driven by electronic circuitry powered by a battery. The battery, circuitry and transducer are mounted in a housing carried by a collar (2) around the neck of the animal (2). The housing (21) includes a first face having an aperture covered by a dust screen. A face of the transducer (15) positioned behind the dust screen (43) radiates compessional wave energy through the dust (43) screen that is reflected from the ground (5) beneath the animal back to the underneath portions (6) of the animal (1). The duty cycle and frequency of ultrasonic pulses derived by the transducer (15) cause the fleas to be repelled. A second face (24), opposite from the first face (23), abuts against the body of the animal (1) and carries a frangible, spring-like plate (22) having a pair of slots (31) through which the collar (2) extends. The plate spring (22) properties and the frictional force of the strap (2) in the slots (31) maintain the housing (21) in situ on the neck of the animal (1), so the compressional waves are directed to the ground (5). If the animal (1) becomes trapped by the housing (21), the plate (22) breaks between the slot (31) and an edge of the plate in response to the animal (1) tugging on the trapping agent to enable the animal (1) to escape.</p> |
