7Q1 



THE INDIA RUBBER WORLD 



[September 1, 1917. 



angle in order to secure a greater strength and to prevent the 

 unraveling of the threads in the strips. Tliese strips, in various 

 plies, depending on the size of the tire, are finally built up on a 

 mold or iron core to form the fabric for the tire. 

 liflLDlNG F.\nKir. 



The "building fabric," as previously mentioned, is the body 

 of the tire. It is 

 the most important 

 fabric and as such 

 must possess above 

 all, strength, flexi- 

 bility and elastic- 

 ity. The fabric is 

 a plain weave, and 

 weighs approxi- 

 mately 17.25 oun- 

 ces to the square 

 yard. The yarns 

 from which this 

 building fabric is 

 made are 11/22.5 

 or 11/23. The twist 

 in the single yarn BriuniNG Fabkl:. 



is from 14 to 16 and the ply yarn is 4 to 5 turns per inch. The 

 texture is 23 ends and 23 picks per inch. The gage of thick- 

 ness of the fabric is .040 inch. The water content should not 

 be over 5 per cent. The take-up is found to be about 14 per 

 cent and the contraction of filling about 10 per cent, leaving 

 normally a difference of 4 per cent in the amount of warp and 

 filling yarn stretch. This is an important point in the con- 

 struction of tire fabric. It is obvious that if the difference is 

 too great, the filling, when the fabric is subjected to a strain, 

 will arrive at its straight length before the warp and conse- 

 quently will weaken or break before the straight length of the 

 warp is reached. When the percentages of crimp or bend in 

 the warp and filling are about equal, or within S per cent of 

 each other, the warp and filling will tend to reinforce each other. 

 In my capacity as fabric inspector I have analyzed so-called tire 

 fabrics which had 32 per cent take-up in the warp and 7 per 

 cent stretch in the filling. The difference of 25 per cent made 

 them totally unfit for use in tires, although the fabrics were in 

 every other respect perfect. 



Building fabric is used in various grades, but the construc- 

 tion remains the same. Sakellaridis, or cotton grown in Egypt 

 from Sea Island seeds, is a material that has become very 

 prominent. The staple is longer and stronger than Sea Island, 

 but is not quite so 

 elastic. In color r 

 is a yellowisl 

 white, a compm 

 mise between Si . 

 Island and Egypi 

 ian. Long staple 

 Sea I s 1 a n ( ! , 



Combed Egypti.c 

 and Carded Egypi 

 ian are also u.s< < 

 in great quantit; 

 chief and most in 

 portant of which i 

 Sea Island. 



Strength ob- 

 viously is the para- 

 mount feature in a tire fabric and upon this factor there cannot 

 be put too much emphasis. Every tire manufacturer, even 

 though he has no fabric inspection department, has at least a 

 tensile strength testing machine. There are various ways of test- 

 ing, and each method results in a dififerent standard of strength. 

 For example, breaking a 3-inch strip in a 2-inch jaw is virtually 



Ch.\fing Fabmi 



testing two inches of fabric, but will yield a higher strength 

 test than if just two inches are tested. This is because the 

 two inches in the former case are reinforced by the threads 

 adjacent, although not held in the jaws of the machine. The 

 standard of strengths, as stated below, is based on a dif- 

 ferent method of testing and yields a lower but truer breaking 

 strength. A piece of fabric is unraveled down to one inch, 

 representing in number of threads the exact texture of that inch. 

 This strip of fabric is placed in the jaws and tested for strength, 

 and can indicate no greater strength than the exact number of 

 threads that inch actually possesses. According to this method 

 of testing the following standard for strength in building fabric 

 is obtained : 



Warp Filling 



Sakellaridis pounds 340 360 



Sea Island 319 320 



Combed Egyptian 275 285 



Carded Egyptian 260 270 



A question may arise as to the cause of the difference in warp 

 and filling strength. When it is remembered that the warp is 

 woven under considerable tension, this difference in strength is 

 readily understood. 



BRE.\KER F.\BRIC. 



The breaker fabric is applied on the tire just beneath the tread 



and its purpose is to protect the building fabric and to distribute 



the shock that the tire necessarily receives on the road over as 



great a surface as 



possible. There are l^vir. »,;-;. , ., . .:'j^-7i .-.i v.* . i*J!3 



manv and varied -li-V. .--->---••• V-r .■«,-,., i. ,_,^,«JB 



many ana varieu ,»,.,..,,,.,., ^ ,i, «*».,»» w.,r»-^»JT»jr« 



constructions of .»»».••«»«# i »« ii« .,.. .#.*»» .j«-« 



breaker fabric, .*»•••*••»•.*•• «-«^ •^^ ».»«.»««•_» •» 



each manufacturer ;:.,...»••»-•.-«,».-«». .v.. » .»• 



having his own ;,-•«-• •»-••-•■••-"-•■••«■• ••-**** «» .j 



particular weave *trt tj T Z ! .' ; I^ii:!:,; Z; I*. It'- M 



and construction. *','.' Ull '.l llZt'llllZZtZ^Z^Ztlt 



The average ^'^tlll'-'' lllZlliZZ^l^ZttltTlt 



breaker fabric, if •«•'•••■*•««•••»«"« •»«.»«»^ ».«4* 



such there be. i> ••-•<'••••"••«-•.«• .ii* «j.»«»i, <«.s»-.u. 



is somewhat simi- •-••.•••*'•'•'•'•*• •^ ii* >•«.«•' «•»<> i^. 



lar m construction ^i'.j^-» «••••.•..-.»■.»- .,-...^ ..- ^.^*- .- 



to the building fmiU' ' ' ' J,-;.'* >^ ; ?:;:n : ;;> : ; 



fabric in respect ~ ;! ' ~: ',, 



. ., T,, I.KK.NKER r.^BRTC, SqU.\RE We.WE. 



to the yarns. 1 he 



texture is very much lower in order to permit large openings 

 in the fabric to accommodate more rubber than the other 

 fabrics. The weight varies, of course, with the construc- 

 tion, but usually is somewhere around 10 ounces to the square 

 yard. Twelve ends and thirteen picks per inch give the neces- 

 sary openness to the fabric. The weave will vary anywhere 

 from a plain weave to a mock leno. It is made of Sea Island, 

 Combed Egyptian or Carded Egyptian. It is difficult to set a 

 strength standard for this fabric, as any change in texture, 

 weave or yarns will greatly modify any standard which may be 

 placed upon it. However, with a construction such as is out- 

 lined above the breaking strength would be as follows : 



Warp Filling 



Sea Island pounds 160 180 



Combed Egyptian 140 155 



Carded Egyptian 115 130 



i-H.\FI\r, F.SBRIC. 

 The chafing fabric is used on the side walls of the tire where 

 more flexibility is required, and is of necessity a lighter fabric. 

 It is a plain weave weighing 9 ounces to the square yard. The 

 yarns are 4/22.5 or 4/23. The gage or thickness is .022. There 

 are 34 ends and 34 picks to the inch. It is made of Sea Island 

 or Combed Egyptian and the breaking strengths are as follows: 



Warp Filling 



Sea Island pounds 155 170 



Combed Egyptian 125 140 



