22 



THE INDIA RUBBER WORLD 



[October 1, 1915. 



With the larger valve rings, a roughing cut is first made 

 with coarse discs to bring the ring down to within 12 thou- 

 sandths of finished size. Finer discs are then substituted 

 and the finishing cut made bringing the valves down to size. 

 The output is 600 to 625 of the small valves per hour, as 

 only one cut is required, and 350 to 370 of the larger valves 

 per hour, as two cuts arc required. [Gardner Machine Co., 

 Beloit, Wisconsin.] 



THE SILENT CHAIN DRIVE. 



The introduction of electric drives in the most progressive 

 rubber mills has greatly changed the appearance of factory in- 

 teriors. The unsightly line and countershafts with whirling 

 pulleys and flying belts are gone. While this is primarily due 

 to the motor drive, it is the application of the chain drive that 

 makes this transformation complete. 



The silent chain consists of stamped links pivoted together 

 forming a multiple chain that is as flexible as a belt and as 

 positive as a gear. Both the drive and driven gears are ac- 

 curately cut to lit the chain. Transmission service in rubber 

 mills is very severe. As a matter of fact gearing has heretofore 

 been used almost exclusively, but the repair and maintenance 

 costs due to the gears transmitting shock, have in many cases 

 caused the substitution of chain drives. 



For heavy intermittent service, such as driving washers, mixers 

 or grinders, where the load often varies from 25 per cent, to 

 150 per cent, within a few seconds, the chain drive is very satis- 

 factory. When applied to calenders the driving force is positive 

 but elastic and is equal at each instant to the uneven load usually 

 carried by these machines. The chain drive is particularly well 

 fitted for driving textile machinery, such as hose braiders, looms 

 and special tire fabric machines. The smooth drive and even 

 turning of rotating parts result in fewer broken threads. It is 

 peculiarly fitted for the operation of air compressors, positive 

 pressure blowers, and similar machinery, and for driving ven- 

 tilating and heating fans. The silent chain permits of compact 

 construction and requires but a minimum of attention. 



The service cost per horse-power of a chain drive is probably 

 lower than any gear, rope or belt transmission, tests on small 



1.000-H. P. ..\ND 500-H. P. M(ii<-i Mil M 1 NM Din 



ING Two Line Sh.\fts in .\ I.\i<m Im mm \Iiii 



Ch.mns: 3-Inch Pitch x 24 IxcHfs W wt \\r. 



Pitch x 12 Inches Wide, Respectively. 



s Ol'ER-^T- 



Sl7E cir 



powers having shown that this efficiency runs from 98^/2 to 99 

 per cent. 



The following comparison is a good example of the greater 

 rompactness of this modern power transmission. 



Rope drive— 1,200 horse-power, 240 to 80 r. p. m., 42 ft. centers ; 

 diameter of driving sheave, 6 ft. 4yi in. ; diameter of driven 

 sheave, 20 ft:; 30 ropes, each 154 in- in diameter — price, including 

 balance wheel weighing 120,000 lbs., $6,900. 



Chain drive— 1,200 horse-power drive, 240 to 80 r. p. m., 100 in. 

 centers; one 31-tooth sprocket, driver 30.21 in. diameter; one 93- 

 tooth sprocket, driven 89.42 in. diameter ; 33.5 ft., 27 in. x 31 in. 

 silent chain — price, not including balance wheel, $3,748.75. 



Two 200-H. P. Link-Belt Silent Ch.mn Drives. Oper.\ting 



Line Sh.-^kts for Rubber Mills. Size of Ch.-mn: 



2-Inch Pitch by 12-Inch Wide. 



The chain drive is now used to transmit power to many rub- 

 ber machines. A total of over 33.000 horse-power in service in 

 rubber mills shows the popularity of this type of power trans- 

 mission. 



A NEW STITCHER. 



tcher is not only a very simple tool, but is 

 seful one. In fact it is almost indispensable 

 in the manufacture of certain goods; for in- 

 stance, in roll- 

 ing down the 

 fabric strips and 

 making smooth 

 The usefulness of 



The hand 

 an extreme! 



tire building. 



jomt 



tliis tool has greatly increased recently, and has resulted in 

 the development of an improved ball bearing stitcher, which 

 is made by the Hoggson & Pettis Mfg. Co., New Haven, 

 Connecticut. 



A NEW HOS'; COUPLING. 



This device does away with hose clamps, straps and coup- 

 lings that require special fastening tools when attaching hose 

 to a threaded terminal. The end of the hose is slipped into 

 the corrugated end of the socket, which is then screwed on 



the threaded sleeve. This is provided with a long taper which 

 expands the hose against the corrugated socket, holding it in 

 a positive grip. No special tools are required to make or 

 break the connection, as ordinary wrenches are sufficient for 

 the purpose. [The National Hose Coupling Co., Peoples Gas 

 Building, Chicago.] 



In the August number of The Indi.^ Rubber World there 

 was shown a very interesting "permanent set" testing ma- 

 chine used in the laboratory of the New York Insulated Wire 

 Co. The invention was credited to M. M. Kahn. of the labo- 

 ratory staff, but Mr. Kahn writes us that it was not his in- 

 vention and we therefore gladly correct the error. 



