ENGINEER'S BRAKE VALVES 135 



stationary by the lower clutch, turning the casing to the left 

 puts the spring under tension and furnishes the power to 

 return the handle to running position. 



Removing Return-Spring Arrangement. To remove the 

 return-spring arrangement, first move the rotary- valve handle 

 to release position and while holding it there remove the casing 

 screw, Fig. 3. Move the handle back to running position, 

 i-emove the handle nut, take off the rotary-valve handle, take 

 out the three cover screws, and remove the cover. Place 

 the thumb over one of the casing lugs and hold down the cas- 

 ing while prying up the upper clutch by inserting a pointed 

 tool under the lug that engages the lug of the casing. This 

 will disengage the upper clutch from the lower one and release 

 the tension of the return spring, as will be indicated by a slight 

 click. The upper clutch, casing, spring, and lower clutch can 

 then be removed in the order stated. 



Replacing Return-Spring Arrangement. In order to replace 

 the return-spring arrangement easily, the rotary-valve key 

 and stem should be in position in the valve body and the 

 casing screw removed. Place the lower clutch on the rotary- 

 key stem with the lug down, drop it into the return-spring 

 chamber, and turn it until the lug is against the return-spring 

 stop and to the right of it, the front of the brake valve facing the 

 person doing the work. Next, drop the spring over the key 

 stem and lower clutch and bring the end of the spring against the 

 right face of the lug of the lower clutch. Next, drop the casing 

 over the spring and bring the return- spring stop lug up against 

 the top end of the spring. Turn the rotary -valve key until the 

 position pin (located near the top of the key stem) points 

 toward the casing-screw hole. Place the upper clutch properly 

 on the key stem with the flat end up, and press the clutch 

 down as far as it will go; this brings the clutch lug between 

 the lugs of the casing. Next, place the brake-valve handle 

 on the key stem and move it to release position; this will put 

 tension on the spring and will bring the screw slot opposite 

 the casing screw. Press down the casing until its lugs are 

 flush with the top of the valve body, and then screw the casing 

 screw all the way in ; it will extend into the slot in the casing as 

 intended. Let the brake-valve return to running position and 



