| 摘要 |
An emergency lighting system having a motor drive assembly (34) for the automatic lowering of a battery-powered emergency lamp (12), when normal power to a primary lighting system is lost, from a concealed position behind a ceiling (11), and returning the lamp (12) to its original position when normal power is restored. Included in the assembly (34) are gears including a motor driven gear (36) and a crank arm driving gear (38). The presence of a normal electric current to the primary lighting system powers the motor drive assembly (34) to return and maintain the emergency lighting system in its concealed position. Interruption of normal electric power automatically results in driving of the emergency power system from its concealed position to an extended position for use, as a result of crank driving gear (38) being rotated in a direction opposite that in which it is rotated for return of the emergency system to the normal concealed position. Resumption of normal electric current returns the emergency lighting system to its concealed position.
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