528 



THE INDIA RUBBER WORLD 



[July 1, 1916. 



in the other direction, thus the threads of the two plies cross 

 each other. 



When the core lias turned one complete revolution ft is cov- 

 ered with a double ply of oppositely placed diagonal threads. 

 Separator rings are applied to certain parts of the carcass and 

 the thread winding operation continued. The separators pre- 

 vent the different plies from sticking to each other so that the 

 bead rings can be inserted and the carcass structure severed on 

 the inner circumference in forming the beads and completing 

 the casing. 



WOVEN CORD FABRIC. 



It can be safely said that with few exceptions, notably the 

 Goodrich Silvertown cord tire, all cord tires now in use are made 

 from a modification of the well-known thread fabric used in 

 making hose pipe bicycle tires. It is composed entirely of cabled, 

 parallel warp cords laid close together and without the usual 

 filler other than small threads of soft, light yarn, spaced about 

 one-half inch apart, that act as tillers but are only a temporary 

 support to the web. In fact, the usyal practice is to inflate 

 an air bag within the unvulcanized .casing that results in each 

 cross thread being broken before the casing is finally cured. 



Thirteen and one-half-ounce Sea Island fabric is generally 

 used for the average cord tire, although 16^-ounce 

 is recommended when size and excessive strain are factors to 

 be considered. The fabric is coated on a spreader which ap- 

 plies several coatings of rubber to both sides of the web, the 

 thickness of the solution and the 'number of coatings depending 

 on the size and service required of the tire carcass. The 

 spreading process not only impregnates the separated cords but 

 preserves their alignment, which would be impossible in cal- 

 endering. The fabric thus frictioned is skim-coated on the cal- 

 ender and then cut on the bias into strips of the required width 

 and length. Thus it will be seen that all air is expelled from 

 the fabric and the individual warp cords are imbedded in rub- 

 ber, thereby reducing to a great extent the friction and conse- 

 quent heating when the tire is subjected to air pressure and 

 unusual strain due to fast driving. 



There is apparently a limit to the size of the cord that can 

 be successfully rubberized in cord fabric form. When the at- 

 tempt was made to use a heavy warp cord in order to make 

 up for the several plies made necessary by the use of lighter 

 cord, the result was a failure, as the rubber could not be satis- 

 factorily driven into the heavy 28J^-ounce cord fabric. 

 P.\r.MF.R'S FLAT CORD. 



A development that grew out of the recognized imperfections 

 in round cord, is a new type of ribbon or flat cord approximately 

 one-half inch wide. According to John F. Palmer, these inex- 

 tensible flat strips can be placed on the tire core at a true tangent 

 to the rim, that is, at right angles to the spokes of the wheel. 



Pal.mf.r's Ideal Tire. 



This position gives the 

 most efficient power 

 transmission from the 

 rim to the tread for the 

 reason that force is best 

 transmitted in straight 

 lines. The illustration 

 shows how the cords are 

 tangent to the rim in the 

 ideal flat cord tire. A 

 represents the axle; B 

 the spokes ; C the felly 

 and D the rim. The cords 

 E, form a bridge con- 

 struction supporting the 

 tire at F. 



SUBF.RS' CORD FABRIC. 

 The inventions of Lawrence A. Subers follow closely along 

 the lines of the cord principle in the development of a new 

 laminated fabric that depends on a flat tubular fabric building 

 strip. Moreover, the mechanical method of constructing the 

 fabric is novel in principle. The fabric is made up of tubular 

 bands, impregnated with rubber, that have alternating wide and 

 narrow portions so that when it is made up in the form of a 

 casing the wide portions will correspond to the tread and the 

 narrow portions to the sides of the tire adjacent to the 



beads. The fabric is laid, not braided- nor woven, around an 

 endless tubular mandrel corresponding in cross section to the 

 general shape of a tire, by a machine that lays the strip around 

 the moving mandrel at an aiii.'lc ni 45 dct;recs, while another 

 layer of strip is simultaneiiu>l\ laid at (>pi)iisite angles, form- 

 ing a laminated tubular fahric. This falirie is slit on the inner 

 circumference and removed from the fnandrel in continuous 

 lengths. These strips are of the correct width and shape to 

 form the various plies of -the tire carcass, which is built up on 

 a separate -machine. 



16y; Ounces. 

 Three Types of Cord Fabrics. 



