| 摘要 |
<p>Retrofit apparatus (38) for attachment to a utility meter (10) to detect revolutions of a dial arm (34) of the utility meter. A piezoelectric crystal (42) is provided against which a striker arm (52) abuts. The striker arm is rotatable on an axle (50) and is therefore movable relative to the piezoelectric crystal. A spring (54) is tensioned so as to resiliently bias the striker arm against the crystal. A shoe (62) is also mounted on the axle and is disposed in the path of rotation of the dial arm so that once each revolution the dial arm engages, deflects, and releases the shoe, thereby causing the striker arm to withdraw from and then snap back against the pieoelectric crystal. The crystal produces an electrical pulse in response. The pulses are counted by a counter (82) to provide a count indicative of utility usage.</p> |
