464 



STEPHENSON'S PATENT 



to each other, and will remain parallel when moved up and down. Each side, 

 CC, has a small projection on its inner side, fitting into a corresponding groove 

 in each wedge, as shown in fig. 41, to guide it when moved; and a bolt, F, 

 is carried upwards from each of the wedges E, through the upper piece B, having 

 a nut screwed upon it at the top ; the holes for the bolts are made oblong to 

 allow for the lateral motion of the wedges FIG. 41. FJC. 4-2. 



when they are screwed up. The two 

 brass bearings, G G, are inserted be- r~ 

 tween the wedges, having flanches on 

 each side fitted on the faces of the 

 wedges ; they are three inches wide, 

 and bored out to five inches diameter, to 

 fit the cranked axle. One of the brasses, 

 G, overlaps the other, which is fitted 

 steadily into it, but not quite touching 

 at the ends. They are made to close 

 upon the axle by screwing up the two 

 wedges E E, thereby forcing the two 

 brasses nearer together; and they are 

 then free to slide up and down between 

 the wedges to allow for the play of the 

 springs, which affects the engine only 

 and not the axle ; and are readily tight- 

 ened up as they wear from friction, by 

 screwing up the wedges farther. 



The cranked axle is thus steadied against the horizontal force of the connect- 

 ing rods, which is the greatest strain that it is subjected to ; but it can have no 

 vertical support in consequence of the play of the springs. A shoulder is made 

 on the bottom of the nuts on the bolts F, and cut into teeth, as shewn in the 

 plan, fig. 44, which catch the ends of a small spring H, fixed by a screw in the 

 middle. This prevents the nuts from turning round and getting loose with the great 

 jolting to which they are subject, the spring having to be forced out from each 

 tooth in succession to let the nut turn ; and though this does not impede the 

 screwing up of the nuts, it is sufficient to prevent their getting loose. The same 

 contrivance is applied to all the nuts in the engine that are used for the adjustment 

 of some moveable part, as those in the glands of the piston rod and slide valve 

 spindle ; as these nuts are not screwed hard up so as to keep them fast. 



Some engines with four wheels are made without the outside frame, and also 



H 



FIGS. 43 and 44. 



