. American telephone practice . FIG. OF TWENTY KELLOGG TACKS. ing rearwardly-projecting portions for facilitating the soldering ofthe wires. The framework of this jack is composed mainly of twohard-rubber strips, the front strip being drilled to receive the tubu-lar portion of the sleeve contacts, while the rear strip is slotted onits upper side to receive the tip springs, and on its lower side to. FIG. 360.—DETAIL OF KELLOGG JACKS. receive the shanks projecting from the sleeve contacts. Under-neath this rear rubber strip is secured a heavy brass strip into whichthe screws binding t
. American telephone practice . FIG. OF TWENTY KELLOGG TACKS. ing rearwardly-projecting portions for facilitating the soldering ofthe wires. The framework of this jack is composed mainly of twohard-rubber strips, the front strip being drilled to receive the tubu-lar portion of the sleeve contacts, while the rear strip is slotted onits upper side to receive the tip springs, and on its lower side to. FIG. 360.—DETAIL OF KELLOGG JACKS. receive the shanks projecting from the sleeve contacts. Under-neath this rear rubber strip is secured a heavy brass strip into whichthe screws binding the tip springs in place pass. A thin rubberstrip is placed between the slotted rubber back strip and the brassstrip, this serving to prevent the sleeve contacts from short-circuit-ing against the brass strip. Grooved end lugs of brass secured to33 514 AMERICAN TELEPHONE PRACTICE. the upper face of the back strip and the rear face of the front stripserve as a means for fastening these spring-jacks into the frame-work of the board. This jack of the Kellogg Company is made in three sizes, thelargest of which is -J inch between centers in a horizontal directionand 7-16 inch in a vertical direction. This size is used by the Kel-logg Company on all switchboards having an ultimate capacity ofnot over 7200 lines. There is another size—§ inch between cen-ters in each direction—which is used for exchange
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Keywords: ., boo, bookcentury1900, bookdecade1900, bookidamericantelepho00mill
