| 摘要 |
Disclosed are a timing device for controlling machine tools, handling equipment or other servomechanical elements and a method of manufacture. The timing device comprises a timing control element which includes a plurality of transparent windows and opaque windows arranged in a selected pattern and a reflective means disposed behind the transparent and opaque windows for reflecting light. A transmitter emits light toward the timing control element. The device further comprise means for operating the timing control element to controllably select one of the transparent and opaque windows to be in the path of the emitted light. The emitted light propagates through one of the transparent windows, and is reflected by the reflective means only when the selected window is transparent. A receiver, disposed adjacent to the transmitter, generates an electrical signal in response to the reflected light.
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