Machine drawing; a practical guide to the standard methods of graphical representation of machines, including complete detail drawings of a duplex pump and of a direct-current generator . above discussion reduces to one funda-mental working condition for belt transmission,viz, The center line of the belt leaving a pulleymust lie in the central plane of the pulley to tvhichthe belt is delivered. This principle is applicable to all cases ofbelt transmission, however complicated, whetherthe shafts be parallel or at an angle. The use of guide pulleys ismerely a means of controlling the delivery of
Machine drawing; a practical guide to the standard methods of graphical representation of machines, including complete detail drawings of a duplex pump and of a direct-current generator . above discussion reduces to one funda-mental working condition for belt transmission,viz, The center line of the belt leaving a pulleymust lie in the central plane of the pulley to tvhichthe belt is delivered. This principle is applicable to all cases ofbelt transmission, however complicated, whetherthe shafts be parallel or at an angle. The use of guide pulleys ismerely a means of controlling the delivery of the belt according tothe principle. The student should commit this principle to memory,and go over its application until he is sure that he understands it;for without it he cannot solve complicated belt problems, and hecannot feel sure of his solution of even the simplest ones. In thepages of discussion and illustration which follow, the student shouldconstantly note the recurrence and application of this principle, asit is really all there is to the solution of belt problems, except familiarknowledge of how to make the drawing projections, which he alreadyis supposed to Fig 95. Theory ofCrowning a Pulley 112 MACHINE DRAWING Tight and Loose Pulleys. Tight and loose pulleys are providedfor cases in which a machine is to be thrown in and out of servicewithout stopping the driving shaft. A common arrangement is shown in Fig. 96, where a pulleywith a straight face is located on the line shaft, and two pulleys withcrowned faces are on the countershaft. Pulley B is loose on theshaft, and C is fast to the shaft. A collar D is placed on left of B,to prevent its end motion. Shifting the belt is accomplished bypushing on the advancing side of belt, close to the receiving pulley.
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Keywords: ., bookcentury1900, bookdecade1910, bookpublis, booksubjectmachinery
