File:The Street railway journal (1908) (14737047956).jpg

Identifier: streetrailwayjo311908newy (find matches)
Title: The Street railway journal
Year: 1884 (1880s)
Authors:
Subjects: Street-railroads Electric railroads Transportation
Publisher: New York : McGraw Pub. Co.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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t is, themalleable iron cap-castings are compressed over the endsof the wood member by hydraulic presure, which distributesthe stresses evenly throughout the entire piece. The malle-able iron cap-castings of the wood breaks are providedwith internally threaded lugs, and are fastened to the end-castings of the section insulator by machine bolts whichpass through holes in the end-castings and engage thethreads in the lugs. Lock washers prevent these bolts frombeing loosened by vibration. Since each of the woodbreaks has an approximate ultimate strength in tension of7000 lbs., it is possible to break the largest sizes of trolleywire without injury to the insulator. The wood breaksbeing situated in the same plane with the trolley wire theyare subjected to no bending moment, being subjected todirect tension stress only. The suspension bar and runner piece are of hard woodand are separate as seen in Fig. 2. The ends of the sus-pension bar, which is ij^ ins. x i 1/16 ins. x 9^ ins., fit into
Text Appearing After Image:
INSULATOR WITH SUSPENSION BAR AND RUNNER PIECES OFHARD WOOD recesses in the faces of the end-castings, and a top suspen-sion is provided for attachment to a hanger with a ys-hi.threaded lug. The runner bar is of the same dimensionsas the suspension bar, the under edge being rounded to fitthe groove of the trolley wheel. It is driven tightly intothe recesses in the end-castings beneath the suspension barand is further held in place by cotter pins as shown inFig. I. This runner bar may be easily renewed. By inspection of the illustrations it will be noted that theend-castings terminate in long grooved ears for the recep-tion of the wires. These ears are each provided on theupper edge with two threaded lugs, 1^4 ins. in diameter,the lugs being bifurcated. A wedge with a grooved andserrated edge, shown in detail in Fig. i, fits into thel)ifurcations of each of the lugs and is clamped down upontlie trolley wire by nuts which fit the lugs. About midwayl)ctwen the lugs there is a projection

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