186 



CONTINUOUS RAILWAY BRAKES. 



the Board of Trade requirements, when not affected by the 

 weather. The friction pulleys occasionally become coated 

 with ice, when the brake is rendered useless. Thus the 

 brake is not quite reliable. The brake is quick in its action, 

 but jerky, booanso the friction between the friction rollers 

 will not admit of graduation. 



It can only be used on short trains ; on long trains the 

 resistance of the springs exceeds the force that can bo 

 transmitted by friction gearing worked fi'om tho roar axle. 



The "Heberlkin" BrjAKK. 



This belongs to Class II. In " Heborloin's " system each 

 carriage carries a complete set of friction pulleys and gear- 

 ing, connected by tension rods with the brake rigging, as 

 shown in Pigs. 1 and 2 for tho engine, and in Figs. 5 and 11 

 for the carriages. 



The friction gearing is tho most important part of tho 

 brake apparatus. A Z-shaped frame, sliown in side and 

 front elevation in Pig. 4, carries a friction pulley, the lower 

 one of the two, and a chain pulley, tho upper one ; the chain 

 pulley is placed to the side of tho friction pulley ; a stopped 

 chain of peculiar construction, made of flat links, is wound 

 off the upper pulley on to the barrel of the lower, or vice 

 versa, according as the brakes are in the act of going " on " 

 or coming " off." 



The rear axle of each carriage carries a frictioir piilloy 

 made in halves, this friction pulley being secured by a 

 key and by bolts. Whon the braltes are " off," tho Z- 

 shn.ped frame is held, away from tho axle by tho tension of 

 the rope transmitted through the inclined tie-rod attached 

 to the swing frame. When this is tho case, there is no 

 frictional contact between tho pulley on tho axle and that 

 carried by the swing frame. 



