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THE INDIA RUBBER WORLD 



August 1, 1921 



against the stone. liach piece of soling is thus held until the 

 grindstone has just ahout worn a hole through it, and an attendant 

 notes the comparative resistance made by each sample to the 

 abrasive action of t!ie whirling stone, the revolutions of which 

 are also indicated by a counter attached to the shaft. 



Tliis machine can be made easily and cheaply in any shop. 

 .\ more elaborate contrivance, employing similar principles, is 

 used by the United States Bureau of Standards in Washington, 

 D. C, for determining the relative values of the materials used 

 for soling armv boots and shoes. 



Applying and Repairing Rubber Belting 



A Bit of History— Leather Belting— Rubber Belting— Wide Field of Usefulness for Rubber Belting— Field Work in Applying and Repairing— The 

 Leather Lacing— Best Lacing Method— Hinge Joint Lacing— L.ace and Lap Fastening— Making a Back Splice— Lap Splicing— Diamond Lap Splice 



A BIT OF HISTORY 



RUBBER belting has been manufactured in the United States since 

 1836, even before vulcanization was discovered by Good- 

 year. It was at first a monopoly under the Goodyear 

 patents controlled by Henry Edwards, of Boston. Later it be- 

 came one of the important lines manufactured by all of the lead- 

 ing mechanical rubber goods producers. 



LEATHER BELTING 

 Leather belting for a great many years had been regarded as 

 the only practical material, combining strength, flexibility, grip- 

 ping power, and endurance, suitable for transmitting power. Ex- 



Steel Belt-Stretcher 



cellent as it was and is, machinery users early noted several seri- 

 ous shortcomings in it. 



Generally speaking, the leather belt worked well indoors, and 

 even outdoors when the weather was dry, but in the presence of 

 much moisture the leather relaxed and lost much of its grip, 

 necessitating the use of various devices to take up the slack. 

 Cold usually hardens and heat warps leather belting. 



Then, too, the leather belt is limited in width, due to the 

 nature of the material ; and generally, in the flat form, it could 

 be used only on one side. Too often the leather belts twisted, 

 ran out of line, due to uneven width or thickness, even some ap- 

 parently high-grade belts being subject to troublesome distortion. 

 Not the least objection was the gradually growing dearness of 

 first-class leather belting. The canvas or cotton belt in various 

 forms was often substituted for the leather in the hope of over- 

 coming some of the drawbacks of the leather belt, but while it is 



Wooden Belt-Stretcher 



still employed to a large extent in certain lines, it absorbs damp- 

 ness too easily, is not easily repaired, and unless exceptionally 

 well made, stretches too much. 



RUBBER BELTING 

 The rubber belt, on the other hand, has all the merits rightly 

 attributed to the time-honored leather belt, practically none of 

 the shortcomings, and many additional advantages. Like tires. 



footwear, and other rubber goods, the modern rubber belt is the 

 result of remarkable evolution in manufacturing. The earlier 

 belts had all the inherent faults of a product of an undeveloped 

 industry and many of the later ones were better made but far 

 too much was expected of them, and the disappointment of too 

 confident buyers hurt the industry. Finally, through the con- 

 fidence and enterprise of rubber manufacturers, and after a great 

 deal of experimenting and rigorous testing, the practically per- 

 fect rubber belt of today was put on the market and soon found 

 favor with progressive industrial managers in all parts of the 

 world. To them it has become indispensable for a host of 

 purposes. 



WIDE FIELD OF USEFULNESS FOR RUBBER BELTING 



The well-made rubber belt is remarkable for its long life. In- 

 stances are cited where main-drive belts of rubber have stood up 

 under the hardest strain for twenty years before renewal was 

 found necessary. The rubber belt is not readily affected by heat, 

 cold, dryness, or moisture, and it can be constructed so as to be 

 impervious to the action of acids, gases and steam. Hence it is 

 preferred for mills, mines, cement works, sugar refineries, 

 bleacheries, grain elevators, oil wells, concentrating plants, dredg- 

 ing machines, and for numerous other purposes where power has 



Single Row Lacing 



to be transmitted or materials conveyed, often under most adverse 

 surroundings. So efficiently is the modern rubber conveyor belt 

 made that it has largely replaced those of iron and steel for 

 handling ores, coal, stone and other rough abrasive materials, 

 and it can be used in situations where a metal conveyor would 

 be impossible. Its latitude as to construction is practically limit- 

 less ; in other words, it can be made to suit the most varied service 

 conditions. 



Presenting a very smooth surface to the pulley and being very 

 pliable, the rubber belt obtains exceptional cling or adhesion, with 

 correspondingly greater transmission of power. This saving in 

 slippage, or greater friction, means a power saving in favor of 

 rubber over leather belting of from 25 to 40 per cent. If a rub- 

 ber belt slips it is usually due to overloading. Vibration in ma- 

 chinery is noticeably less, and wear consequently reduced, with 

 rubber belting, as on account of its even surface, uniform strength 



