548 



THE INDIA RUBBER WORLD 



[July 



THE ROUTING OF MATERIALS IN A MODERN TIRE 

 PLANT. 



IN planning a maniilacturins; plant the first reiiiiisite is that the 

 materials and the articles manufactured shall be advanced 

 from one process to the next by the most direct route, with no 

 duplication of handling. The layout of the entire plant should 

 be planned to this end. The diagram shows the routing of crude 

 rubber, compounding ingredients and fabric, step by step to the 

 finished tire casing and inner tube, in an up-to-date tire plant. 



This diagram is the key to the location of the store rooms, dry 

 rooms, working departments, machinery, tools and equipment, 



division will have charge of standardization work in regard to 

 solid and pneumatic tires, rims, felly bands, etc. It will therefore 

 take up some of the incomplete work upon which the Truck 

 Standards Division has been working, including the following 

 subjects : Carrying capacities of solid tires ; carrying capacities and 

 inflation pressures of pneumatic tires ; depth of solid metal rims 

 for demountable solid tires. 



Routing of M.\teri.\ls in a Modern Tire Plant. 



which should be placed and arranged to permit progress of ma- 

 terials through the necessary processes to the finished product 

 with the least possible deviation from a straight line. The plan- 

 ning should also allow possible enlargement of departments with 

 but a minimum of disturbance of the existing plant. 



Low cost, known exact cost, decreased damaged stocks and 

 finished goods, full time and consistent production from the 

 worker, a maximum output from equipment. — all these are neces- 

 sary for success, and a well-arranged and thoroughly organized 

 plaijt makes this success far better assured than one built and run 

 under the old "rule-of-thumb" method. 



EUROPEAN TIRE DIMENSI^ON ANOMALIES. 



THOSE who have had occasion^to meas^iire European pneu- 

 matic automobile tires, for fitting speeddrrieTers, or for other 

 purposes, have noted that the metric measurements indicated on 

 these tires very seldom correspond with their actual dimensions. 

 For instance, a tire marked 760 x 90 millimeters [29.92 x 3.S4 

 inches] does not actually measure 760 millimeters in diameter; 

 nor does an 880 x 120 millimeters [34.65 x 4.72 inches] tire 

 actually measure 880 millimeters. Here is the reason : 



In the early days of the automobile tire industry, when 

 Michelin, the pioneer, began to make "large tires"— large when 

 compared with the 65 millimeter [2.56 inches] section tire which 

 was the first type of automobile tire produced — he made them 

 according to his own judgment, and in sizes demanded by auto- 

 mobile manufacturers, without any idea of the dimensions corre- 

 sponding with even numbers of centimeters. He made inner 

 tubes of 105; 120; 135 millimeters [413; 472; 5.32 inches], all 

 of which could be fitted to rims c,f approximately the same size, 

 and he adopted the method, still in vogue today in Europe, of 

 designating automobile tire sizes by two numbers, the first refer- 

 ring to the diameter of the wheel with the inflated tire upon it, 

 and the second relating to the sectional diameter of the tire. 



It was soon found that chauffeurs experienced difficulty with 

 the fractions of centimeters in ordering tires and, to make it an 

 easy matter for them to remember tire sizes, Michelin decided 

 to have the two numbers designating the tire terminate with the 

 same figure or figures having a similar consonance when named 

 in the French language. For instance, 810 x 90, stated in French 

 is hiiit cent dix, qiiatre-zingt-dix. This was the origin of the 

 automobile tire size designations that today are still current in 

 Europe, and of which the principal ones are as follows : 



; TIRE AND aiM STANDARDS COMMITTEE. 



The Society of Automobile Engineers has a new division of the 

 Standards Committee to be known as the Tire and Rim Division, 

 of which H. L. Barton is chairman. The other members of the 

 committee are as follows : W. H. Allen, C. C. Carlton, J. E. Hale, 

 Russell Hoopes. C. B. Whittelsey, C. E. Bonnett, John Kelsey, 

 J. V. Mowe, J. C. Manternach, C. B. Williams, E. K, Baker, J. C 

 Cole and Christian Girl. Most of these men were formerly on 

 the Truck Standards Division, or the Pleasure Car Wheels 

 Division, which latter was discontinued last vear. The new 



Michelin adopted these designations arbitrarily, without making 

 any changes in the actual sizes of the tires, the numbers 

 marked upon them being changed to suit euphony and to make 

 them easy to remember. Hence the anornalies and confusion. 



In a number of these confused designations, hovvever, tlie fig- 

 ures referring to the sectional diameter of the tires represent 

 approximately the correct measurements of the casings, not when 

 they are^new, Ij.ut after they Have covered several hundred miles. 

 New tire casings swell during the first few hundred miles of 

 their we*ar_ai)d .an '826 x 120 millimeters [32.28 x 472 inches] 

 casing, that measures when new a little rriore than 110 millimeters 

 [4.33 inches] in sectional diameter, will measure its full 120 milli- 

 meters [4.72 inches] after running from 200 to 300 miles. 



As far as the exterior diameter of the tire is concerned, the 

 designating numbers marked on European millimeter tires are 

 never more than approximate. 



