Modular type indicator unit

Claim 1

IN A MODULAR TYPE INDICATOR UNIT, IN COMBINATION: AN ELONGATED CASING INCLUDING A BACK WALL AND A FRONT OPENING; AN ELONGATED LAMP HOLDER NORMALLY RECEIVED IN AND CLOSING SAID FRONT OPENING AND REMOVABLE THEREFROM FOR SERVICING, SAID HOLDER INCLUDING A BACK HAVING A PAIR OF LAMP SOCKETS SPACED ALONG THE LENGTH THEREOF; A PAIR OF LAMPS MOUNTED IN SAID SOCKETS AND HAVING SIDE CONTACTS AND END CONTACTS; MEANS PROVIDING A CONNECTION THROUGH SAID SOCKETS TO SIDE CONTACTS OF SAID LAMPS; A BACK CONTACT IN THE FORM OF A YOKE INCLUDING A CURRENT CONDUCTING BAR NORMALLY BRIDGING BETWEEN AND ENGAGED BY THE END CONTACTS OF SAID LAMPS, A PAIR OF FINGERS COMPOSITE WITH AND EXTENDING REARWARDLY FROM THE ENDS OF SAID BRIDGING BAR AND HAVING AT THEIR REAR ENDS RESPECTIVE HOOKS PROJECTING LATERALLY THEREFROM GENERALLY PARALLEL TO SAID BAR; A BRACKET OF YOKE FORM INCLUDING A CURRENT CONDUCTING BASE ATTACHED TO SAID CASING BACK WALL, A PAIR OF ARMS PROJECTING FORWARDLY FROM SAID BASE PAST THE REAR ENDS OF RESPECTIVE FINGERS OF SAID BACK CONTACT, AND STOPS ON THE ENDS OF THE RESPECTIVE ARMS, PROJECTING TRANSVERSELY THEREFROM FORWARDLY OF SAID HOOKS IN OVERLAPPING RELATION THERETO; A SPRING ENGAGED UNDER COMPRESSION BETWEEN SAID BASE AND SAID BRIDGING BAR AND NORMALLY PRESSING SAID BACK CONTACT INTO YIELDING ENGAGEMENT WITH SAID END CONTACTS OF THE LAMPS WHILE ESTABLISHING AND MAINTAINING ELECTRICAL CONNECTION BETWEEN SAID BRACKET AND SAID BACK CONTACT, SAID HOOKS ENGAGING SAID STOPS TO LIMIT THE SPRING-LOADED FORWARD PROJECTION OF SAID BACK CONTACT WHEN SAID LAMP HOLDER IS REMOVED FORWARDLY FROM SAID OPENING; SAID TERMINALS CONNECTED RESPECTIVELY TO SAID BRACKET BASE AND TO SAID SOCKETS.