. Canadian foundryman (1921). to the pitch asthe space is to the whole circle. If the space is but one-twelfth of the cir-cumferenc, and the difference in the twomeasurements is one foot, the pitch is twelvefeet. This is only for a straight pitch. Always look before stepping off thesidewalk. Never cross behind a streetcar without first looking very carefullyfor vehicles on the other track. Making Patterns for Gearing—Rudiments The Principles on Which Gearing Works AreShown Before Going Into the Actual Pat-tern Making IN OUR last lesson we showed twotangent cylinders revolving againsteach other
. Canadian foundryman (1921). to the pitch asthe space is to the whole circle. If the space is but one-twelfth of the cir-cumferenc, and the difference in the twomeasurements is one foot, the pitch is twelvefeet. This is only for a straight pitch. Always look before stepping off thesidewalk. Never cross behind a streetcar without first looking very carefullyfor vehicles on the other track. Making Patterns for Gearing—Rudiments The Principles on Which Gearing Works AreShown Before Going Into the Actual Pat-tern Making IN OUR last lesson we showed twotangent cylinders revolving againsteach other, the one driving the otherby friction. Friction is not reliable andwe must add teeth while still retainingthese circumferences. In Fig. 2 thecircles represent the two cylindersshown in the last lesson. In the peri-phery of these two cylinders, as shownin Fig. 2, cut equidistant grooves. From Brown and Sharps works weget the following: In any groovedpiece the places between grooves arecalled lands. Upon the lands add parts;. Figs. 2 and 3 show the tangent cylinders shown in Nov. lesson, as they appear when converted into gears. these parts are called addenda. A landand its addendum is called a tooth. Atoothed cylinder is called a gear. Twoor more gears with teeth interlockingare called a train. A line, C. C. asshown in Figs. 2 and 3, between thecenters of two wheels is called the lineof centers. A circle just touching theaddenda is called the addendum circumference of the cylinderswithout the teeth is called the pitchcircle. This circle exists geometricallyin every gear find is still called the pitchcircle or the primitive circle. In thestudy of gear wheels it is the problemso to shape the teeth that the pitchcircles will just touch each other with-out slipping. On two fixed centers there can turnonly twn circles, one circle ion eachcenter, m a given relative angular vel-ocity, and touch each other withoutslipping. The groove between two teeth is call-ed a space In
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfoundri, bookyear1921
