. Railway mechanical engineer . Three applications of the 50.(XX)-lli. were made. The formIf the Iirst application cur\e beynnd the nia.\imum point of the,^ curve indicates that the spring was taking a permanentset. and in order to obtain consistent results a second load wasapplied for which no values were recorded. The return (5f therelease load curve to the initial point of the third application curveindicates that fairly constant conditions had been reached. After this test was completed the spring band was machinedoff and the camber nf the |)lates recorded. They were thenres
. Railway mechanical engineer . Three applications of the 50.(XX)-lli. were made. The formIf the Iirst application cur\e beynnd the nia.\imum point of the,^ curve indicates that the spring was taking a permanentset. and in order to obtain consistent results a second load wasapplied for which no values were recorded. The return (5f therelease load curve to the initial point of the third application curveindicates that fairly constant conditions had been reached. After this test was completed the spring band was machinedoff and the camber nf the |)lates recorded. They were thenreset and retempered. lieing lifted with a total opening lietweenthe plates of .s in. before banding. This was the minimumspace that it was possible to obtain with ordinary care in lif-ting, being so slight that the increase in camber due to bandingwas scarcely perceptible. The spring was then tested under thesame conditions and with the same loads previously used, theresults being pintted in Iis. IS. It was thought that with the. Fig. 19 plates lilted dead a spring would take a smaller permanentset than one fitted with considerable draw between the tests here recorded indicate that this is true up to a loadof 30,000 lb., which is nearly SO per cent greater than the loadfor which the spring was designed. The peritianent set resultingfrom the 50,000-lb. load, however, shows practically no differencefor the two experiments. The curves would seem to indicatethat beyond a certain point the amount of permanent set takenby the spring is practically the saine irrespective of the methodof fitting the plates. It should be stated that the load of 50,000lb. applied to the spring in this test is much greater than thespring will ordinarily be called upon to sustain in service. Among shop men the opinion is generally held that springsbuilt with openings between the plates are more flexible thanthose fitted with the plates dead. This may be true to acertain for the reason that
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
