

THE INDIA RUBBER WORLD 



[August 1, 1915. 



the cutting roll. The latter is a cylindrical file, 1 inch in diam 

 eter by 6 inches long, mounted on bearings and driven by a 

 one-eighth electrii belted to either of two 



id pulleys by means of which variable speeds may be 



ill I hi preferable speeds are 1,200 and 



olutions per minute, corresponding to surface speeds 

 at tin il ->14 and 628 feet per minute. The lower speed 



is adapted to the harder qualities and the higher to the softi r 

 qualities I he machine samples effectively all grades of cured 

 r from vulcanite to pure soft rubber. 



By its use small samples of vulcanized rubber are prepared 

 without change of composition. Owing to its finely divided 

 condition, the sample must be protected from oxidation un- 

 immediatelj used, and for the same reason precaution- 

 must be exercised against oxidation during analysis. 



This machine is identical in principle to that invented by 

 Thomas Gare For powdering vulcanized rubber preparatory to 

 reclaiming. United States patent 969,100 (1910). 



A "PERMANENT SET ' TESTING MACHINE. 



Under the present methods of procedure of the Underwriters' 

 Laboratories lor physical testing of rubber insulation, a new 

 factor has been introduced in obtaining the so-called "permanent 

 set" on a stretched test piece. The insulation is required to be 

 stretched from 2 to 5 inches for insulation 4/64 inch or under or 



— A 



from 2 to 4 inches for insulation 5/64 inch or over, held at that 

 mark for 2 minutes and then released. Two minutes after release 

 the marks should not be more than 2' > inches apart. 



A simple apparatus has been designed by M. M. Kahn, of the 

 New York Insulated Wire Co., and in use in the laboratory of 

 that company, especially to take care of the above mentioned test. 



Referring to the illustration. A is a Eureka silk tester gradu- 

 ated in quarter pounds up to a maximum of 20 pounds ; B is a 

 heavy glass cover to protect the dial, and c is a 2-inch strip of 

 leather, one end attached to the tester A and the other end to 

 the clamp /'. The clamps D and E are provided with two pins, 

 one being fixed and the other working freely in the socket. F 

 is another leather strip, one end of which is fastened to the clamp 

 E and the other to the shaft. H is the hand crank, / the ratchet 

 wheel and A." the pawl that holds the tension wherever desired. 



In making the test a piece of insulation about 8 inches in length 

 has marks placed upon it. 2 inches apart. Each end is passed around, 

 then under and through the clamp, so that when stretched the 

 tension pulls the movable pin against the insulation and prevents 

 it from slipping. The pawl is set on the ratchet wheel and the 

 lever is rotated, stretching the test-piece until the marks are 5 

 inches apart. After the sample has remained under tension the 



required 2 minutes it is released by raising the pawl and taken out 

 and the set noted. When permanent set has been obtained the 

 test piece can be replaced in the clamps and stretched to the 

 breaking point. For simple tests on elongation and rupture the 

 pawl can lie released. 



The apparatus can also be used in testing any kind of strip 

 rubber where permanent set. elongation ami tensile strength are 

 required. 



ONE THOUSAND TON TRUCK TIRE PRESS. 



There has been a constant demand for increased pressure 

 on truck tire molds during vulcanization, which has resulted 

 in the construction of the press illustrated herewith. Its 

 lit is sixty-five tons. It has a thirty-six-inch diameter 

 ram. and is de- 

 signed for a hy- 

 draulic working 

 pressure of two 

 thousand pounds 

 per square inch. 

 The vulcanizing 

 chamber is sixtj 

 inches in diam- 

 eter and is ade- 

 quate to take a 

 stack of molds 

 twelve feet in 

 h eight. The 

 height of the en- 

 tire press over 

 all is thirty-five 

 feet, but w hen 

 installed below 

 the level of the 

 curing room 

 floor, only three 

 feet of the press 

 project a b o v e 

 the fli ii ir. 



This press is 

 equipped w i t h 

 the Akron-Wil- 

 liams boltlcss, 

 quick opening 

 type head, which 

 is lifted out of 

 the way. leaving 

 the vulcanizing 

 c b a in b e r eii- 

 t i r e 1 y un- 

 obstructed when 

 molds are to be 

 inserted or re- 

 moved. T h e 

 separate outside 

 packing glands 

 are provided for 

 both steam and 

 water, and an 

 oiling ring lubri- 

 cates the ram. 

 cylinder and 

 glands. 



To provide for the enormous ram thrust it is equipped with 

 six 6-inch stay bolts, and the vulcanizer shell itself is subject 

 to steam pressure only, thus relieving the shell from all 

 hydraulic pressure. This press provides efficient and eco- 

 nomical means of vulcanizing truck tires under high pressure. 

 [The Williams Foundrv & Machine Co.. Akron. Ohio.l 



