File:The practical telephone handbook and guide to the telephonic exchange (1906) (14569520400).jpg

Identifier: practicaltelepho00pool (find matches)
Title: The practical telephone handbook and guide to the telephonic exchange
Year: 1906 (1900s)
Authors: Poole, Joseph
Subjects: Telephone
Publisher: New York, Macmillan Co.
Contributing Library: Northeastern University, Snell Library
Digitizing Sponsor: Boston Library Consortium Member Libraries

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bolts shown theygrip the tubes, and leave spaces for the bolts of four insulators.The arms thus formed are 42 inches long, for 4-wire arms asshown, the 8-wire arms being 78 inches long. The dimensionsare shown in the sketch, and Fig. 326 gives a section^ with bolts 350 PRACTICAL TELEPHONE HANDBOOK and nuts on a larger scale. Arm combiners are clamped bylonger bolts provided, as shown in Fig. 345. These are employedwhenever more than one arm is used. Staying.—Iron poles must be well stayed, as they have nolateral strength by themselves. At least four stays must beattached to the shortest, and longer poles made up of two orthree tubes should have at least eight—four fixed near the top,and the others at the next joint below. Each of the staysshould be provided with a stay tightener or screw-swivel, andthe lower end should be attached preferably to a wall plate,securely nailed to the outer main wall of the building. If thiscannot be done, the stays may be attached to the main timbers
Text Appearing After Image:
T Fig. 345.—4-Wire Channel-Iron Arm of the roof by means of rafter swivels and pivot hooks, whichare fixed by a bolt passed through the timbers, but they mustbe carefully made off with lead, etc., to prevent leakage of rain;or the stays may be attached to iron-wire bands passed roundheavy chimney stacks, the corners of the stacks being protectedby angle plates. Two or more stays may be attached to thesame wall plate or other fixing, but each should be providedwith a separate thimble. The staying of iron poles is very important, and great careshould be taken that it is thoroughly well done. Double poles are made up of two, and triple and multiplestandards of three or more upright poles connected by speciallong arms, providing for 8, 12, and 16 wires. From the largersizes of these, Exchange Standards can be constructed of 3, 4,or more sides. Fig. 346 gives a view of such a square standardmade up with eight uprights. When such structures as these AERIAL LINE CONSTRUCTION 35* are used,

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