The Works Of Messrs. Schneider And Co.

TYRE SHOPS. 55 the varions hydraulic machines are driven by a horizontal Corliss engine with two cylinders, non-condensing ; the pumps are in the same line as the steam cylinders. Some of the leading dimensions are as follows : Diameter of steam cylinders ,, pump piunger Length of stroke .......... Water pressure ............ .550 in. .070 m. 1.100 in. 65 kilogs, 21§ in. 23| in. 3 ft. 7-^ in. 924 Ib. per sq. in. All the piping is laid down in passages easy of access thus giving facility for inspection. of brittleness of the metal, and each railway company has its own conditions for tests. For good quality tyres the lieight of fall varies from 2.700 to 5 metres (8 ft. 10 in. to 16 ft. 5 in.), and the number of blows from two to four. The total deflection produced varies from 10 to 25 per cent, of the original inside diameter. For a superior quality of tyre the conditions are much more strict ; the number of blows varies from four to six, and the height of fall from 8 to 12 metres (26 ft. to 39 ft.). For the second dass of test, a piece is cut out from the part which has suffered the least from the effects of the fall Fig. 133. Falling Weight Tests for Tyres. Testing Tyres.—The falling tests of the tyres are made in a tower 20 metres (65 ft.) high (see Fig. 133). There are in this tower two dropweights weighing each one ton, and having a maximum fall of 16.700 metres (54 ft. 9| in.). The anvil block beneath weighs 10 tons, and is fixed on three cubic metres (106 cubic feet) of masonry foundations. A hydraulic press is erectecl in an adjacent part of this building for special tests. As a rule, tyres undergo two kinds of tests—drop and tensile tests. The chief obiect of the former is to ascertain the degree tests. These pieces must show an ultimate tensile strength which varies, according to conditions imposed by the rail- way Companies, from 40 to 75 kilogrammes (25.40 to 47.62 tons per square inch), the élongation being 12 to 20 per cent. Tests are made on one tyre for eaeh cast ; one cast represents from thirty to ninety tyres. The Southern of France Railway, instead of tensile tests, insist upon compression tests ; these are effected on a tyre which has been bored to its exact thickness. The deflection must be 17 per cent, under a determined load, which varies according to diameter and section. The tyre