r,;_' MAC111M DRAWING AND DESIGN 



and aft-r ii i.s niriM-d. planed, and bored 

 as to cut off the cap A. The parts A and B are held together 

 by two bolts as shown. This md of tin- rod i. titt.-d \\ith 

 brass steps, which arc lin.-.l with \\ hit.- m.-t.il. The cross-head 

 rn<: and through the prongs of the fork passes a pin 



D, which also passes through t he cross-head, whi. -h is forir.-d ..n 

 t<. the piston rod or attached to it in some oth 



Marine ' -"<l. Draw all tin- \u-\\s 



ii in fit:. 53 of one form of marine connecting rod. 1 

 drawings ..i the locking arrangement for the nuts see fig. 19, page 

 21. Sc-jilr I inches to a 1 



Coupling Hods. A rod used to transmit tin- mot ion 

 rank to another is called a coupling rod. A familiar rx.-nnj.lr 



iieuscof coupling rods will be found in tin- loromol 

 Coupling rods are made of wrought iron or steel, and 

 generally of rectangular section. The ends are now generally 

 made solid and lined with solid brass bushes, without 

 *<(], / in-tir. This form of coupling rod end is found 



to answer very well in locomotive practice where the work- 

 manship and arrangements for lubrication are exr^lknt. 

 When the brass bush becomes worn it is replaced by a n w 

 one, 



54 shows an example of a locomotive coupling ro- 

 tor an outside cylinder engine. In this case it is desirable to 

 have the crank -pin bearings for the coupling rods as short as 

 possible, for a mi meet MIL: rod and coupling rod in this kind of 

 engine work side by side on the same < -rank j-in, whirh. I 

 overhung, should be as short as convenient for the sake of 

 strength. The requisite bearing surface is obtained by ha\ in;,' 

 a pin of large diameter. The brass bush is prevented from 

 rotating by means of the square key shown. The oil-box is 

 cut out of the solid, and has a wrought iron c ov-r slightly 

 dovetailed at the edges. This cover fits into a und 



the top inner edge of the box, which is originally parallel, but 

 is made to close on the dovetailed edges of the cover by i ; 

 ing. A hole in the centre of this cover, which gives access to 

 the oil-box, is fitted with a scr-w-d brass plug. The brass 



