. The practical telephone handbook and guide to the telephonic exchange . both sides of long poles toenable the workmen to gain the are fixed alternately on either side,so that they form steps 15 inches apart vertically or 30 incheson each side. When terminating, and in other cases, the arms should beso fitted that the pull draws them towards the pole instead ofagainst the head of the arm bolt. Under ordinary conditions the poles should be about 65yards apart-, or 27 poles to the mile, but the number may varybetween 22 and 30 to the mile according to circumstances. Strength of Ropes.—
. The practical telephone handbook and guide to the telephonic exchange . both sides of long poles toenable the workmen to gain the are fixed alternately on either side,so that they form steps 15 inches apart vertically or 30 incheson each side. When terminating, and in other cases, the arms should beso fitted that the pull draws them towards the pole instead ofagainst the head of the arm bolt. Under ordinary conditions the poles should be about 65yards apart-, or 27 poles to the mile, but the number may varybetween 22 and 30 to the mile according to circumstances. Strength of Ropes.—For the mens safety it is very importantthat the sash lines and ropes used shall be of adequate ropes are generally used, the sizes being based on theircircumferences ; thus a 3-inch rope means one which is 3 inchesin girth. Eopes should be kept dry as they lose a great dealof their strength when wet. The breaking strength in poundsof a manila rope is given by S = 605G-2. G being the girth ininches. The safe working load L = 121G2. S and L for tarred. Fig. 336.—Dead-Manfor Pole-raising 344 PRACTICAL TELEPHONE HANDBOOK
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecttelephone, bookyear19
