Cantilever arm signal assembly

Abstract

A traffic crossing signal mast for railroad-highway grade crossings incorporates a sturdy cantilever arm extending over the highway and supporting a maintenance catwalk. A short, horizontal jury mast at the end of the cantilever arm is pivotable about its axis parallel to the highway direction through limited angular sectors of one-quarter turn clockwise and counterclockwise. A junction box assembly mounted at each end of the jury mast suspends a pair of warning flasher crossing signal lamps on each side of the catwalk aimed down the highway axis. Pivoting movement of the jury mast from its locked, detent position to a latched quarter-turned position raises one of each pair of signal lamps for initial cable connections, repairs or replacement of flashing lamp heads. A lockable clamping cam lever disengages the detent for jury mast rotation and re-engages it to secure the signal lamps in their aligned position for use. A novel catwalk-and-frame assembly is provided for ease of fabrication, incorporating aluminium chord extrusion frame members with integral concave ledges for supporting catwalk panels of expanded metal or perforated plates.

Dependencies are inferred from the claim text.