ENGINEER'S BRAKE VALVES 



137 



it is known as schedule SWA and weighs 16 Ib. The piece 

 number, with brass handle, complete, is 2,626; with a malleable- 

 iron handle, 19,382. The piece and reference numbers of the 

 various parts are given in the accompanying list. 



PC. No. Ref.No. 



Name of Part 



18,721 



1,367 

 1,292 

 1,368 

 5,191 



1.293 

 1,294 

 1,291 

 2,616 



Body. 



Shaft-cap nut. 



Valve cap nut. 



Quadrant. 



Quadrant bolt and nut. 



Shaft, complete, includes steel wearing 



plates. 



Leather shaft washer. 

 Shaft-spring washer. 

 Shaft spring. 

 Valve, complete, includes 11, 12, 13, and 



14. 



Valve stem. 

 Valve. 



Valve leather. 

 Valve nut. 

 Valve spring. 

 Brass handle, complete, includes 17, 18, 



19, 20, 21, and 22. 

 Malleable-iron handle complete, includes 



17, 18, 19, 20, 21, and 22. 

 Latch spring 

 Latch. 

 Latch screw. 

 Handle clamp bolt, complete, includes 21 



and 22. 



Clamp bolt, only. 

 Thumb-nut. 

 Pin. 

 Valve spring. 



Operation. To apply the brake, the handle 4 is moved to 

 application position. This movement causes valve 12 to be 

 unseated, and allows air to flow from the chamber below the 

 valve, past valve 12, into the upper chamber and thence into 

 the pipe leading to the brake cylinder. In this position, the 

 other valve is closed so that no air can escape to the exhaust. 

 If the handle is left in this position, the brake-cylinder pressure 

 will equalize at 45 Ib. that being the pressure at which the 

 slide-valve feed-valve for the straight-air equipment is set 

 to reduce to and no higher brake-cylinder pressure can be 

 obtained with the straight air. 



