444 STEPHENSON'S PATENT 



to the ends of each of these levers by a steel pin passed through them, with a 

 small pin and washer at the end, to prevent its getting loose ; the other ends 

 of the links m" m" , being attached in a similar manner to a socket on the valve 

 spindle I ', which is guided at its end by an eye in a small pillar fixed on to the boiler. 



The eccentric rods d' d", taking hold of the bottom levers h" h'", make them move 

 backwards and forwards with the eccentrics; and the top levers I" I'", connected with 

 them by the weigh-bars i" i'", communicate the motion to the valve spindles 

 by means of the links, m" m"' ; the levers h" and I" being of the same 

 length, the motion of the slide valves is the same as the throw of the eccentrics, 

 or three inches, as before stated. The links allow for the oblique action 

 of the top levers which move in an arc of a circle, instead of a straight 

 line as the valve spindle. The pins and eyes of the levers are all of steel, to 

 diminish .the wear, and are fitted very accurately, so as not to allow any shake 

 when the motion is rapidly reversed at the end of each stroke, and that the slide 

 may be moved the full three inches. The eccentrics E' and E" are placed at right 

 angles to each other, that they may be both in the same relative position to the 

 respective cranks ; and they are fixed in such a position with regard to the crank, 

 that the port is full open, or the slide at the end of its motion, when the piston is 

 at half stroke, as shewn in Plate XC. The eccentrics are therefore at right angles 

 to their respective cranks, and they have to be fixed a quarter of a revolution 

 behind the cranks, in order to move the slides as much in advance of the pistons ; 

 because the levers h" and I" reverse the motion, so that when the slide has to be 

 pulled back, the eccentric rod must be pushed forward. 



REVERSING GEAR. The eccentrics, E' E", are placed so as to work the engine for- 

 ward ; and when the crank is down, as in Plate XC., to cause the piston to be pushed 

 back, and pulled forward when above the axle, and thus cause the wheels to turn 

 round in the direction of the arrow, and propel the engine forward. In order to 

 make the engine run in the opposite direction, two other eccentrics, F' and F", are 

 necessary, which are placed exactly in opposite directions to the former ones, or 

 at the extreme back position when the former ones are at their greatest throw 

 forward ; their rods, f'f", have forks at the ends, similar to the other eccentric 

 rods, and levers, n" n", corresponding to them are fixed on the other ends of the weigh- 

 bars i" i'", exactly like the levers h" h'". The four eccentric rods have pins fixed 

 into them below the forks, and attached to the suspending rods, o"o", o'"o"; the 

 two middle rods, o" o", for the working eccentrics, E' E', being connected at the 

 top to a cross head at the end of the horizontal lever p", and the other two, d" o", 

 for the reversing eccentrics, forked at the top, and attached to the levers p" p", 



