436 



STEPHENSON'S PATENT 



middle of the cross head, and are held upon the end of the connecting rod, T, by 

 the iron strap, X, fitted between the flanches of the brasses and fixed to the connecting 

 rod by the key and gib Y, so as to hold them firmly and steadily together. The 

 key Z is put through the connecting rod and strap close to the inner brass U; the 

 holes in the strap being made larger than the key at the outer end, so that the key 

 bears against the brass U, and forces it against the brass on the cross head. The 

 connecting rod moves upon the cross head, and the friction causes the brasses 

 to wear, so that they require tightening up occasionally by driving in the key 

 Z farther, and bringing them nearer together ; a little space is left between the 

 brasses to allow for this. Small screws are inserted opposite to each of the keys, 

 and are screwed against them when they are driven into their places to prevent 

 their jolting loose. 



The construction of the other end of the connecting rod is shewn on the same 

 scale in figs. 20 and 21, which are a plan and a longitudinal section of it. 



FIG. 20. 



FIG. 21. 



A is the end of the connecting rod, which is enlarged at B B to five inches and 

 three quarters wide, and cut out to an octagonal shape at the end, fitting the brass bear- 

 ing C. The other brass, D, is similar to it, and they are both three inches wide, with 



