| 摘要 |
A window shade located between the two window panes of a window is automatically driven by two electric motors attached to the roller of the window shade so as to place the window shade in a raised position or a lowered position in accordance with the polarity of the power supplied to two electric motors. A relay, when activated, provides power to a manually activated switch having two positions to control the polarity of the power supplied to the electric motors. When deactivated, the relay bypasses the manually activated switch and provides power to the electric motors having a polarity to place the window shade in its lowered position.
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