30 



THE INDIA RUBBER WORLD 



[October ; I 



the use of that company's tires on all the motorcycles employed 

 in the department. 



* * * 



The Universal Tire Co. is purchasing additional equipment 

 for its automobile tire plant at Anaheim, ' alifornia, the presi 

 .lent of t li«- company, II. II. Haldaway, having recently visited 

 the eastern market for this purpose. 



Tin Davis-Frj Manufacturing Co. is turning out at its plant in 

 Oakland. California, a line oi pneumatii tires and lulus for auto- 

 les as well as a solid truck tire, under tin- brand name "ller- 

 cules." The patent rights of this company cover the making of a 

 tread with fabric on edge, a new feature in construction which is 

 said to prevent skidding and to add greatly to the durability of 

 the lire. The fabric is placed at acute angles with the road. 



FATIGUE IN MOTOR TRUCK TIRES. 

 By A. P. Eves. 



""PlIE automobile truck as it is known todaj is the product of 

 ■*■ less than ten years' thought ami endeavor and the whole 

 industry is suffering from want of experience. The tires are the 

 most talked of part of the machine, because 'hey are the subject 

 of more trouble and more expense than all other parts of the 

 machine combined. This condition finds the manufacturer of tires 

 at fault. He has not progressed as fast as the manufacturer of 

 oilier truck parts. Solid tires for large trucks are made along 

 the same lines and with practically the same chemicals as horse- 

 drawn vehicle tires were compounded from ten years ago. Ex- 

 cessive strains due to high speeds under heavy loads, it seems, 

 have been entirely over-looked in tire construction. 



I be steel manufacturer was not long in arriving at the con- 

 clusion that steel as made when the automobile was in its in- 

 fancy would not stand the repeated work under heavy loads of 

 the speeding machine. The automobile industry brought forth the 

 need of an anti-fatigue steel. I lie steel manufacturer produced 

 nickel, chrome-nickel, vanadium and a host of other special 

 steels to nn 1 1 the demand; and they met it nobly. 



Solid tires do not stand the work required of them. Tires that 

 are guaranteed for 8.000 and 10,000 miles on the average in New 

 York and Philadelphia do not run 2.500 miles. To be sure they 

 iri adjusted, but there is the delay and inconvenience of the 

 change. 



Tire manufacturers after two or three years of observation and 

 Mm spasmodic experiments, have adopted a schedule of carrying 

 capacities which is now considered standard. This scheduli con 

 cerns itself altogether with the dimensions of the tire lint 

 specifies nothing whatever about the composition 'I the tire 

 It does nut mention a standard densitj or include a physical re- 

 quirement. 



A mw steel had to be made in stand the strains of the fast 

 going and heavily loaded machine. The automobile made possible 

 the anti-fatigue steel. Rubber is much like steel in many re- 

 spects. In the by-gone days of small carriage tires, if the tire 

 had a good tensile strength, with proper elongation and set, il 

 was considered good. The automobile industry has brought 

 forth the fact, that altho rubber may be up to requirements in 

 tensile strength, elongation, and have the necessary resiliency, 

 when it is subjected to repeated work undergoing vibrations 

 caused by shocks it must possess other qualities to enable it to 

 'meet these entirely new conditions:; Take a small piei i of rubber 

 one inch square and of any convenient length, hold it so that two 

 inches of its length can be stretched an infinite number of times. 

 If die two inches of the exposed surface is stretched to two and 

 a half inches a certain number of times it will break. Now, 

 then take another piece of the same composition and same 



dimensions and fasten it so that the exposed two inches are- 

 compelled to stretch three inches. It will also break but in 

 much less than half the time. As these strains approach more 

 nearlj I- the elastic limit, the deterioration is enormously 

 hastened 11ns fact assumes great importance when it is noted 

 that the deterioration does not take place at the same rati m all 

 compounds. 



\ one inch section of a good solid tire compound should 

 elongate 5' J to 1. That is. the one inch section should stretch 

 live and one-half times. It should take between 1,500 pounds 

 and 1,600 pounds to produce this elongation, when the test piece 

 will break. One hundred pounds will probably stretch this test 

 bar one-half inch; if ibis load can be repeated several hundred 

 times the test piece will break, yet it has never at any time had 

 the full load which is at least 1,500 pounds. The rubber has 

 been worn out by the repeated load of 100 pounds, and this is 

 the action that wears out the tires in service and the greater 

 the load the sooner the tires wear out. This action is called 

 the fatigue. 



Compression is another factor in the disintegration of the 

 solid tire. Tf a load of 25 pounds is placed on a square nub of 

 rubber it will yield; if the load is removed the test piece will 

 fly back to its original form. If this action is repeated a great 

 number of times the rubber will disintegrate. This is a quality 

 that should be taken into consideration in the manufacture of the 

 anti-fatigue tire. This is the action a rubber tire gets under load 

 Repeated elongation and compression under a standard load 

 should be a great factor in producing the truck tire of the future 

 The man that owns the truck is the one that suffers most from 

 bad tires, and he should insist on having good tires, as they are 

 cheaper in the long run. Then he should be careful of them 

 Overspeeding and overloading would break axles, steering 

 knuckles and springs if it did not wear out the tires, hut as tires 

 are made for the protection of the other machine parts they are 

 the first to go. 



The automobile industry has brought forth the «eed of an 

 anti-fatigue tire or a compound as near anti-fatigue as possible. 

 The automobile manufacturer is also partly to blame for the poor 

 showing of the tires today. He does not insist on quality ; all he 

 asks is a long mileage guarantee and a low price. Quality is not a 

 consideration, and it is cheaper to make replacements thai to 

 give quality, for adjustments are not made at manufacturers 

 prices. 



A RUBBER COMB WITH A HOLLOW BACK. 



This "Revelation" bard rubber comb illustrated hen cannol 

 be properly classified under new goods, for as a matter of fact 

 it has been on the market for several years and was described 

 quite a long time ago in this publication; but it probabb ,l ' ■ "■ 



Revelation Hard Rubber Come 



lo many people, and it certainly is interesting, as it has tin 

 appearance of a very heavy comb and yet, its broad, round 

 back being hollow, it is distinctly a light comb. Its size makes 

 it easy to grasp, and its lightness makes it comfortabli i' 

 and less, liable to break when it falls. (.Marburg Kubbei I omb 

 Co., 33! Broadway; New York) 



Replete with information for rubber manufacturers— Mr. 

 Pearson's "(rude Rubber and Compounding Ingredients ' 



