An elementary treatise on the mechanics of machinery, with special reference to the mechanics of the steam-engine by Leconte Joseph N. (Joseph Nisbet) 1870-1950

Author:Leconte, Joseph N. (Joseph Nisbet), 1870-1950
Language: eng
Format: epub
Tags: Mechanical engineering, Steam-engines
Publisher: New York, London, The Macmillan company
Published: 1902-03-25T05:00:00+00:00

Fig. no

Digitized by VjOOQ IC

CAMS

157

OP through A. Construct arcs about 0 as a centre cutting the radii in B, C, Z>, and JS, and the line OP in W, X, Y, and Z. On arc 1 B lay off BR equal to IV1, on arc 2 C lay off CS equal to X2, etc. Then obviously ARSTU will be the pitch curve of the cam.

In the second case of disk cam, the motion which can be given to a follower is not so universal as that which can be given by the first. The manner of constructing the cam curve to satisfy a given

condition is as follows: let A A", 11", 22", 33", and 44" (Fig. in) be successive positions of a bar which moves parallel to itself in the direction OQ. Let the corresponding radii of the cam which successively occupy the position OQ be OA, O 1', O 2', O $\ and #4'. Suppose we bring the cam to rest by giving the whole an equal and opposite rotation about O. The lines 11", 22", 33", and 44" will take up the positions XX 11 , YY", ZZ", and UU\ where th?se are drawn at right angles to the several radii, from

points projected by circular arcs from 1, 2, etc. But these lines must all touch the cam, hence they form the envelope of the required curve. That these conditions cannot always be fulfilled, can best be seen by referring to Fig. 112. If the line which forms the envelope intersects its previous positions in points 1, 2, 3, 4,

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.