LAMP FAILURE DETECTION AND CHANGE DEVICE

摘要

1298443 Lamp changer MINNESOTA MINING & MFG CO 9 Jan 1970 [10 Jan 1969] 1265/70 Heading F4R [Also in Divisions G4 and H2] A projection system has a solid-state detector 35 for detecting the failure of a main lamp 40 and replacing it by an auxiliary lamp 42. The detector 35 actuates a solenoid 51 which pulls back the spring 41 off step 52 and thereby permits spring 38 to move the support 36. The two lamps may be mounted on the same wall of the support. In use a transparency is placed on glass stage 16 and the light is focused by Fresnel lens 18. An indicator lamp 73 is energized when the main lamp fails. The lamp changing system may also be applied to traffic lights.