446 
STEPHENSON'S PATENT 
their forks, and force them into the notches in the bottom of the forks. The re 
versing eccentrics, F' F", are thus brought into gear, and made to work the slides, 
causing the motion of the pistons to be reversed by the steam being admitted on the 
opposite side of them, and making the engine run in the opposite direction to its 
former course ; the middle eccentric rods, e e", are at the same time lowered, as the 
outside ones were before, allowing the forks upon them to clear the pins of the levers 
h" Ji". The engine can then be propelled forward again by putting the hand lever 
over into its front position ; dropping the rods of the outer reversing eccentrics out of 
gear, and drawing up the inner rods of the forward working eccentrics to force the 
levers of the weigh-bars into the opposite positions by their forks, and take hold of 
the pins in them. 
The engine can thus be made to run either forward or backward, by merely 
pulling the hand lever w forward or back; and the handle is placed close to the 
engine man, who stands behind the fire-box, so as to be readily moved; it is fixed 
so as to drop into the notches, and requires pulling out of them to shift its position, 
in order to prevent its jolting loose. The suspending rods, o'o'", that support the 
ends of the eccentric rods, have to be moved with the eccentric rods in working, 
causing some friction to the engine; those rods that are in gear have to be held close 
up to the pins on the levers of the weigh-bars, that they may not get out of the 
notches in the eccentric rods; and their motion does not exactly correspond with 
that of the pins in the levers of the weigh-bars, from the suspending rods 
taking hold below the notches of the eccentric rods, and moving in an arc of a rather 
larger circle, causing a little additional friction from the sliding of the pins in the 
notches, though the amount of it is very small. To obviate this, the eccentric rods 
are placed in some engines above the pins in the levers of the weigh-bars, with the 
forks and notches inverted, so as to drop down upon the pins and rest upon them 
when in gear ; allowing the suspending rods to have a loose hold of them, as they 
do not require support. This plan is liable to the objection, that if the eccentric 
rods should accidentally get loose by the pins jolting out, they would all fall into 
gear and cause the breaking of the machinery, as they move in opposite directions; 
but with the other arrangement the eccentric rods would in this case merely fall 
upon a rod that is fixed under them across the engine. 
This plan of reversing has been but lately introduced, having been first used 
by Messrs. Stephenson, and since adopted with different modifications by other 
makers. The plan in many locomotives is, to have the four eccentric rods 
suspended above the levers of the weigh-bars in a similar manner to the last, but 
with notches only in their under side, so that they cannot take hold of the lever 
pins until they have moved along, and the notches coincide with the pins; the