152 



THE INDIA RUBBER WORLD 



[February i, 1904. 



RUBBER AND TEXTILE TESTING MACHINES. 



THE textile fabrics embodied in rubber goods are designed 

 to give the finished product the element of strength re- 

 quired to adapt it to the conditions of service. Hose for all 

 purposes, and belting, are notable examples of rubber goods 



designed to withstand 

 heavy strains in service. 

 The element of strength is 

 also important in such lines 

 as footwear and clothing, 

 carriage cloths, tires, and 

 many other lines which 

 might be specified. 



A convenient and accu- 

 rate mechanism by means 

 of which exact knowledge 

 of the strength of fabrics 

 can be ascertained is very 

 necessary. Several ma- 

 chines specially adapted to 

 this work are to be had in 

 the market. Among these 

 are the "Arch power " ma- 

 chine of Riehl^ Brothers, 

 and a vertical form made 

 by the Falkenau-Sinclair 

 Co., both of Philadelphia. 

 Figure 1 represents the first 

 of these testing machines. 

 It has a capacity of 600 

 pounds pull and may be operated by either hand or belt power. 

 The power mechanism is extremely simple, consisting of a 

 worm and gear driven by pulleys through straight and crossed 

 belts. A conveniently arranged lever disengages the worm 

 and the machine can then be operated by throwing the 

 miter gear into mesh and using the hand wheel. The strain 

 is measured by a standard spring balance and the recoil is taken 

 up by a pair of wedges which follow the downward pull and 

 prevent shock to any extent. An idle index indicates the maxi- 

 mum load or breaking strain of the specimen. The machine as 

 illustrated is designed and constructed for the bureau of equip- 

 ment of the United States navy yard at New York. 

 It is operated by a one sixth horse power motor. 



The vertical form of machine as built by the Falk- 

 enau-Sinclair Co. (Fig. 2) is very compact and ar- 

 ranged for hand power operation only. The strain is 

 applied to the cloth by means of worm gearing, and 

 is indicated by a maximum hand on the dial of a 

 spring balance, and the recoil of the balance is obviat- 

 ed by a following up wedge all precisely as in the 

 "Arch power " machine. The hand lever shown im- 

 mediately under the dials in both forms of machine 

 is for controlling the release of the spring of the balance 

 when the wedge system in the rear is disengaged. For rapid 

 work the worm can be thrown out of gear and the screw run up 

 or down rapidly by the hand wheel. The machine is built in 

 two sizes for 200 or 600 pounds capacity. 



Another machine of horizontal form, built by the same con- 

 cern, is specially designed for applying a tensile test to rubber. 

 Figure 3 illustrates this machine as used, somewhat modified, 

 in the testing room of the bureau of equipment at the Navy 

 Yard. This machine consists of a bed plate, movable upon 

 which is a spring balance and a grip for the test piece, and be- 

 tween them a removable wedge which follows up the pull on the 



balance and holds it at the maximum strain when the break oc- 

 curs. These movable parts are made so by being mounted on 

 small trucks or wheels to reduce friction. The strain is applied 

 through a screw by means of power or the hand wheel at the 

 end of the machine. 



There is also a hand wheel at the 

 side which operates a rack and 

 pinion for moving the carriage rapid- 

 ly to its original position after a 

 test has been made. Opposite the 

 movable grip is a fixed one, which, 

 however, can be made movable by 

 removing a stud. In this way tests 

 for stretch and set may be made by 

 attaching dead weights to the hook 

 by means of a cord passed over the 

 sheave. The machine is also pro- 

 vided with a graduated scale and 

 pointers with which the original 

 reference marks on the test piece 

 may be followed as the specimen is 

 stretched and thus the elongation 

 be determined. 



Numerous careful tests, by the 

 bureau of equipment, Brooklyn 

 navy yard, under 

 widely v a ry in g 

 conditions of 

 dampness of the 

 goods and the hy- 

 grometric state of 

 the air have 

 demonstrated that 

 the only reliable 

 tests of the 

 strength of tex- 

 tiles are those o'o- 

 fig. 2 tained where the 



pieces have been prepared test subjected to 150* F. for six 

 hours and are taken singly from the drying oven and promptly 



fig. 3. 

 broken in the machine. These are the specified conditions of 

 test under which all grades of duck are purchased for the 



United States navy. 



Portable Pneumatic Tool Outfit.— There is in use on 

 the Great Southern and Western railway, in England, a car 

 designed for repairs to bridges and other work along the road, 

 equipped with an outfit of pneumatic tools supplied by the In- 

 ternational Pneumatic Tool Co. The outfit embraces a steam 

 driven air compressor, 12 HP. boiler, an air reservoir 6 feet 

 long and 2.% feet in diameter, and an assortment of hammers, 

 riveters, drills, and the like, together with several lengths of 

 metal protected rubber hose. 



