THE INDIA RUBBER WORLD 



brief outline is typical of them all. The stock (either rectangular 

 in cross section or of some special shape) is lirst cut to the proper 

 length corresponding to the circumference of the rim. It is then 

 formed up into a circle by rolling. The surfaces near the ends 

 are slightly ground or sand blasted to remove the rust and scale 

 to assure good contact in the welding dies. The rim is then placed 

 in the welder for a period of from a few seconds to a minute and 

 a half, depending upon the size of rim, which is the time required 

 for making the weld, .\fter welding, the rim is removed from the 

 welder and the fin removed while red hot, by means of an air 

 chisel, or it is sheared off in a special machine. Next, the welded 

 portion is smoothed down by grinding and the rim brought to 

 e.\act size by a special hydraulic shrinking machine or if under 

 size, the rim is expanded upon a bulldozer. The subsequent 

 operations necessary to .tinish the rim for mounting are not of 

 interest in connection with this subject. 



It is estimated that approximately 75 per cent of the power 

 taken from the lines is converted into heat and used directly in 

 making the weld. The efficiency of the charcoal, coke, gas or oil 

 fire in no way is comparable to this. Further, the use of the 

 electric method vastly increases the output obtainable over the old 

 method when employing a given number of men. And, moreover, 

 the ends are held in absolute alignment and uniform results 

 always assured. 



The following table will give an idea of the current consumed 

 and time taken in making welds by the electric process. In this 

 table the time taken can be reduced by increasing the power, or 

 I'icc versa. 



Area Power Time Power 



Square Inches Kilowatts Seconds Horse-power 



1.00 18.75 40 25.0 



1,50 29.5 44 39.5 



2.00 33.0 57 44.0 



3.00 43.5 70 58.5 



4.00 56.3 80 76.0 



5.00 61.7 90 83.0 



6.00 69.0 98 92.5 



While there are several machines used for electrical rim weld- 

 ing that are designed to perform a great variety of work, the 

 illustrations and descriptions are of typical rim machines. 



The welder shown in Figure 1, welds flat stock up to 6 x }4 

 inches, or 1 x ;4 inches, or li/s inch round stock. This machine is 

 designed for welding automobile rims, which are rolled to size 

 and welded flat. The flat bands are then shaped in special rolls to 

 fit the rubber tires. An exceedingly fine adjustment is obtained 

 in the clamping dies by four eccentrics mounted in the heads and 

 operated by worm gears. After the stock is clamped in the jaws, 

 two levers mounted on cams give the final pressure to avoid the 

 possibility of the stock slipping in the dies. On ordinary stock, 

 4 inches wide by 9/64 inch thick, a man will weld from 450 to 600 

 rims per day ; 6 x ;4 inches, 350 to 400 per day, and 3^ x Ys 

 inches, 600 to 700 per day. 



The machine shown in Figure 2 welds rims up to 12 inches 

 wide by 'A inch thick. It requires a heavy and well constructed 

 machine, both mechanically and electrically, to heat and compress 

 a piece of steel 6 square inches in cross section. This type is 

 designed for welding this heavy stock and all parts are necessarily 

 massive and substantially made. It is especially constructed for 

 welding heavy flat band stock. 



The Society of Automobile Engineers has issued a sheet show- 

 ing to what extent the various automobile manufacturing com- 

 panies are using S, A. E. standards in their manutacture. An 

 examination of this sheet shows that 27 manufacturers of solid 

 tires and 24 manufacturers of pneumatic tires have adopted these 

 standards, while in insulated requirements 12 are using these 

 standards, and 9 have adopted the standard tests of insulating 

 materials. 



BRITISH SOLID TIRE RIM STANDARDS AND 

 AMERICAN SIZES. 



OUR British contemporary, "Motor Traction," has of late de- 

 voted space to a controversy relating to the advisability of 

 prohibiting or, at least, placing a heavy duty upon, the importa- 

 tion of American commercial motor vehicles not conforming to 

 British' tire standards. 



The British Finance Act, 1915, placed iS'/j per cent duty upon 

 imports of motor cars, chassis, motorcycles and parts and ac- 

 cessories of motor cars and motorcycles, except tires. Commer- 

 cial cars were, however, excepted from the operation of the tax 

 and were also left without mention in a recent royal proclama- 

 tion prohibiting the importation into Great Britain of pleasure 

 cars and accessories (except tires). 



The controversy above referred to was started by an open letter 

 to our contemporary in which it was argued that the importation 

 of American motor trucks, not conforming with British standard 

 tire sizes, would introduce an element of disorganization into the 

 British trade, as there would necessarily be a demand for various 

 American tire sizes for at least 5 or 6 years after they had been 

 placed in service. It was pointed out that after the mutual agree- 

 ment that had been made between British automobile manufac- 

 turers and tire manufacturers, it would be regrettable that 

 American importations should upset all calculations and neces- 

 sitate diff^erent molds, and consequent disorganization, not to 

 mention increased expense in the production of solid tires. It 

 was further stated that for American sizes, British tire manufac- 

 turers would be at a disadvantage when competing with American 

 manufacturers. It was, therefore, proposed that a duty of 33^ 

 per cent be levied upon American motor trucks (the same as was 

 levied on pleasure cars before their importation was prohibited 

 altogether), unless they conform to the British standards in 

 construction and equipment. 



The matter was taken up by other readers of "Motor Traction," 

 one of whom went so far as to propose that combined pressure 

 be brought to bear to induce the government to absolutely pro- 

 hibit the importation into Great Britain, her dominions and 

 colonies, of trucks which do not, so far as as their wheels are 

 concerned, comply with British standard sizes. British tire manu- 

 facturers had been put to great trouble in competing for the 

 business in furnishing odd size tires for trucks which were al- 

 ready in use in England. It could not be expected that users 

 would go to the expense of altering wheels to accommodate 

 British standard tires, and, either the tire manufacturer would 

 have to stand this expense, or continue to produce tires from 

 molds of suitable American sizes. 



A correspondent presenting the other side of the case— there 

 are always two sides— pointed out the advantage to the commer- 

 cial community which had resulted from the free importation 

 of American trucks at a time when British manufacturers were 

 unable to guarantee deliveries and the fact that an examination 

 of American wheel and tire sizes showed that there were only 

 six of these, three of which had been adopted by the American 

 Society of Automobile Engineers as standards. The manufac- 

 ture of the three or six American sizes was quite a different 

 matter from the manufacture of the multiplicity of millimeter 

 sizes which was taking place in Great Britain prior to the adop- 

 tion of the British standards. All these old millimeter sizes 

 promise to be wiped out in the course of the next five or six 

 years, as soon as the vehicles become obsolete. The matter is 

 receiving the earnest consideration of British, American, French, 

 Italian and Belgian manufacturers of both tires and automobiles, 

 and there is promise of an international agreement on the sub- 

 ject. Such an agreement would be made difficult should ill feel- 

 ing be raised by premature action. 



Replete with information for rubber manufacturers.— Mr. 

 Pearson's "Crude Rubber and Compounding Ingredients." 



