| 摘要 |
The cat hatch involves a fixed part (6) which can be set in an outer wall or in an outer door. In the fixed part is an openable hatch (8) and an opening mechanism (13) which activates the hatch opening. A monitoring device (18) on receipt of signals (15) from the movable part activates the hatch opening mechanism, whereby free passage is afforded to the cat wearing the movable part. The signal emitted from the signal producer (1) is coded. The producer is activated by a magnetic field (16) produced from the fixed part (7). The signal coming from the signal producer is so weak or has such a frequency that it requires free passage from the emitter (2) to the receiver (10). The radio emitter incorporates a crystal oscillator with a stable frequency. The frequency value can be programmed, but practical research shows that 800 kHz is suitable. |
