Public works . Springcushions in the differential gear assemblyserve to absorb all sudden strain thrownon the gearing. The scarifier is attached to the rearof the roller and the same operatorhandles both. The additional weight ofthe complete attachment is about A steam pressure cylinder,which is under instant control of theoperator, by manipulating a four wayvalve, is employed to raise and lowerthe teeth. The teeth are forced into theground under a steam pressure of 4 tonsand are held there by a steam picks are quickly raised or loweredin passing over cross walks, manh
Public works . Springcushions in the differential gear assemblyserve to absorb all sudden strain thrownon the gearing. The scarifier is attached to the rearof the roller and the same operatorhandles both. The additional weight ofthe complete attachment is about A steam pressure cylinder,which is under instant control of theoperator, by manipulating a four wayvalve, is employed to raise and lowerthe teeth. The teeth are forced into theground under a steam pressure of 4 tonsand are held there by a steam picks are quickly raised or loweredin passing over cross walks, manholecovers and other immovable obstacles. The I/z x 2j4 x 22-inch scarifierteeth are made of tool steel accuratelyforged and carefully tempered. Thepicks are adjustable for depth and gaugewheels prevent them from digging belowthe required depth in case the rear rollsdrop into a hole in the road. The width of cut can be varied from40 to 56 inches, depending on the spacingof picks or any picks can be EI,,V CONTROLLEDPENETROMETER .\fter seven years of experimentalwork an electrically controlled penetrom-eter has been perfected, for use intesting laboratories, to automatically timepenetration tests of plastic substances. It is manufactured by Howard &Morse and is recommended by them forthe elimination of personal equationwhen testing asphalt, bitumen, tar, rubber and other material, where the un-known factor of human error is claimedtl be replaced by clockwork instrument contains a timing de-vice by means of which an electric cur-rent, acting through a magnet, releasesa bar carrying the penetration needle,allowing penetration to be effected for agiven period, at the expiration of whichthe bar is automatically clamped by themagnet and the depth of penetrationmeasured. The instrument can be connected tosix dry cells or their equivalent or thecurrent inay be supplied from 110 voltdirect circuit, connecting through a re-ducer or from 110 volt altern
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectmunicip, bookyear1896
