48 



THE INDIA RUBBER WORLD 



[November i, 1903. 



ATTACHING WRINGER ROLLS BY MELTING- 



THE old style making of wringer rolls by molding and cur- 

 ing the compound onto the shaft was superseded by the 

 method of building up by hand a calendered sheet of stock on 

 the copperized shaft, cemented and covered by a ply of bard 

 curing rubber to insure a firm union between the iron and the 

 body of the roll. The cure was effected by subjecting the cloth 

 wrapped goods to open steam. This method involved consider- 

 able hand labor in building up the roll, but permitted the man- 

 ufacturer to face the roll with a ply of high grade stock. 



Excellent work may be made in this way, but " rolls for the 

 million " are better made by forcing the stock from a heavy 

 tubing machine, delivering it very close to size, or small enough 

 to receive a facing ply, and ready to be cut in two-roll lengths. 

 In this state the double length roll is slipped onto a short 

 mandrel, and rolled in a wide piece of sheeting, which is drawn 

 tightly about it in a small three-roll wrapping machine of the 

 ordinary form. The ends of the wrapper are then tightly tied 

 down to the mandrel, and dozens of such rolls thus prepared 

 are placed, standing endwise, in a rack ready for curing in open 

 heat. After this process, it remains to unwrap and remove the 

 rolls, ready for cutting to length and sandpapering to size on a 

 lathe. It requires some skill to force the uncut rolls onto the 

 tightly fitting lathe mandrels. This is done by resting the 

 mandrel on the floor with the upper end slightly entered in the 

 roll. Then, covering the upper end of the roll tightly with one 

 hand, a sudden downward thrust of the workman's right hand 

 compresses the air in the roll sufficiently to permit it to slip 

 completely onto the mandrel. 



The attachment of a cured roll to the shaft is effectually ac- 

 complished as follows : The shaft is brought to dull redness its 

 entire length and is then used to melt or burn out the hole in 

 the roll enough to thoroughly smear both hole and iron their 

 entire length with sticky compound. The iron is then quickly 

 quenched in water to a heat below the melting point of the rub- 

 ber. At this stage the roll is replaced on the shaft and, with a 

 few blows of the shaft on an anvil, jarred down to place. The 

 heat remaining in the shaft is sufficient to cure the roll so 

 firmly to the iron that on cooling it can only be removed by 

 cutting the rubber away. A little practice is necessary to 

 properly judge the heat of the iron after quenching, that it may 

 not continue melting the interior of the roll and produce a cav- 

 ity or unattached spot. Such a spot would, of course, permit 

 the roll to twist and tear in service. The layer of hard curing 

 cement formed by melting the rubber should be as thin as pos- 

 sible, and the hole not enlarged beyond the size for a snug fit. 



This method of attachment is adopted by leading wringer 

 makers for new work as well as by rubber manufacturers for 

 repair work. A few experiments will enable an ordinary me- 

 chanic to attach rolls in this way, efficiently and cheaply. 



RUBBER FACTORY APPLIANCES. 



CURING, STRIPPING, AND REVERSING INNER TUBES. 



THE old style method of straight wrapping and cross wrap- 

 ping inner tubes of rubber was used for many years 

 in every factory devoted to their manufacture. It was at 

 last modified by using a straight wrapper of increased dimen- 

 sions, and omitting entirely the cross wrapper. This was 

 not only a distinct saving in time and wrappers, but the tube 

 was kept free from all markings and variations in thickness 

 caused by irregular cross wrapping. A still further improve- 

 ment is now effected by curing the tubes with no wrapping at 

 all. The mandrels are supported on racks to prevent contact 



and the tubes come out perfect in every respect. 



The removal of inner tubes from the mandrels on which they 

 are cured was formerly very generally accomplished by distend- 

 ing the tube with a large bubble of air and forcing it slowly 

 along the mandrel by hand pressure. The tube thus loosened 

 from the pole slipped off readily, but required to be reversed 

 on a rod by hand to bring outtermost the finished side. [Fig. 1 ] 

 /»//«/•!</ see- / ion 



/14ar,ef/-e/ 



A far more expeditious method for removing and reversing at 

 one operation consists in turning back upon itself a few inches 

 of the inner tube at one end, and under this reversed portion 

 inserting a strong blast of air as into a pocket. The tube dis- 

 tends and separates from the mandrel at the point of doubling 

 or reversing as rapidly as it can be pulled backward and off the 

 mandrel. [See Figure 2.] Three men can remove and reverse 



J/i//a Tion ,<xne/ 

 Rey et-sion 



3000 tubes a day by this method. One man handles the poles 

 before removal of the tubes and one the bare poles, while the 

 third operates the air and strips the tubes. Precisely the same 

 method may be employed for removing and reversing sample 

 cotton hose tubes when cured, as usual on short mandrels. 



Reversing flat cured inner tubes is neatly accomplished by 

 employing a hollow pole through which air is being exhaust- 

 ed. One end of the tube is slipped over the air inlet end of 

 the pole. A partial vacuum occurs and the tube is sucked 

 through the pole reversing as it goes. The operator releases 

 his hold and it passes through, making way for the next. 



TO IMITATE CUT SHEET. 

 Cut sheet, or " patent rubber," as the Continentals term it, is 

 notable for a surface crossed by very fine lines that give it a 

 distinctive and attractive appearance. Pure gum sheet pro- 

 duced by spreading in any manner does not normally possess 

 those lines, which, by the way, are caused by the rapidly oscil- 

 ating knife that shaves the sheet from the pressed block. That 



calendered stock may have the appearance of cut sheet, how- 

 ever, the sheeting calender, shown in the accompanying illus- 

 tration has been designed. It is very simple, having two graven 

 rolls, arranged so that they may be set for different thicknesses 

 of stock. Once through the fluting calender is enough to give 

 the desired surface, which is permanent even after vulcaniza- 

 tion. [Max Miiller, Hannover-Hainholz, Germany.] 



