. Railway master mechanic [microform] . ent of V disengages Wt andthrows Jf\ into engagement with Ut. The order of engagementas V is shifted to the right is thus. Ut, Ut, Ut, Ut, etc. V is shifted by means of a sleeve Z attached to its outer end,which has rack teeth cut in it meshing with pinion Y, at thelower end of the vertical rock shaft shown in Figs. 2 and shaft has a handle or knob X, and carries a dial with fig-ures corresponding with the pair of gears engaged. Referringto the feed and thread plate at the front of the head-stock, theoperator may find the number of threads per inc
. Railway master mechanic [microform] . ent of V disengages Wt andthrows Jf\ into engagement with Ut. The order of engagementas V is shifted to the right is thus. Ut, Ut, Ut, Ut, etc. V is shifted by means of a sleeve Z attached to its outer end,which has rack teeth cut in it meshing with pinion Y, at thelower end of the vertical rock shaft shown in Figs. 2 and shaft has a handle or knob X, and carries a dial with fig-ures corresponding with the pair of gears engaged. Referringto the feed and thread plate at the front of the head-stock, theoperator may find the number of threads per inch given by eachof these eight positions, in combination with the four changeseffected by the horizontal levers. The feeds are five times asfine as the threads. The advantages of this form of gear box lie in the shortaxial movement required for the sliding keys, and the corres-pondingly compact arrangement of the controlling mechanismfor the eight changes. Owing to. the fact that when one of the February, 1909 RAILWAY MASTER MECHANIC 55. Fig. 5—Adjustable Friction Drive for Apron Feeds. keys is in engagement the other is withdrawn, there is little wearon the hardened washers separating the gears. A much betterselection of threads has been provided in this box than usualowing to the fact that the gears have not been limited to evenpitches. Where it was necessary in the gear box, in obtaininga desired ratio, to employ fractional pitches, this has been donewithout hesitation, so that the pitches of different gears vary,though they are most of them about nine diametral. Each ofgears L\ and U2 has six splines in its bore, so that they engagequickly. Provision is made for disconnecting either the feed rodor the lead-screw from the feeding mechanism, by means of thesliding gear and sliding clutch shown at the right of Fig. 4. The details of the carriage construction follow the standardpractice of the builders in most particulars. There are, however,two point of improvement which are
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1895
