March i, 1906.] 



THE INDIA RUBBER WORLD 



193 



THROPP'S DUCK SLITTER. 



WRAPPING MACHINE FOR TIRES. 



\ MACHINE not often found in the small rubber shop is 

 ■^-^ the cluck slitter. Its use, however, is such a saver of 

 time, such a pronounced advantage over cutting duck or 

 other fabrics by hand, tliat it has become indispensable 

 wherever' belting is made or any other article manufactured 

 by the rubber trade, containing duck that requires longitu- 

 dinal cutting, or, in factory parlance, " slitting. " 



Although machines for slitting duck have been used for 

 many years, there has been little change in their general 

 features, the one illustrated here being one of the latest 

 model. This lack of change or improvement possibly is ow- 

 ing to the machine, leaving little working margin, so to say, 

 for the imagination. 



A machine like the one illustrated here will handle duck 

 in any width of weave. The roll of fabric to be slitted is 

 hung upon a detachable bar. The free end of the fabric is 

 carried forward between the knife bar and the cutting cylin- 

 der, and attached to the mandril or shell, upon which it is to 



be wound, the power for winding or re-rolling being impart- 

 ed through the medium of a sprocket chain as shown. The 

 knife bar is hung with adjustable "dogs " or guides, each 

 slotted to hold a knife which is held in place by a set screw. 

 The cylinder over which the fabric passes and which is in 

 reality a cutting table, is of iron, hollow, and sometimes 

 covered with brass. Its surface is cut with longitudinal 

 grooves, y^ inch deep, about yi inch apart, which engage 

 the point or edge of each cutting blade used, preventing the 

 swerving of the knife, and insuring a straight cut. Any 

 fabric is liable to wrinkle as it is drawn over the cylinder 

 against the knives, and to further prevent this, the "dog " 

 or guide on the edges should be provided with a long curved 

 spring of flexible steel so placed as to press upon the fabric 

 at the point of cutting, thus holding it in smooth contact 

 with the cylinder. 



This method admits of slitting the fabric at one operation, 

 to as many strips as may be required. Running at moder- 

 ate speed, requiring for its operation four to six horse 

 power, upward of 400 yards can be slit in a half hour. The 

 machine shown in the illustration is manufactured by Wil- 

 liam R. Thropp, Trenton, New Jersey. 



'nr^HE machine illustrated here has been designed specially 

 -*- for wrapping inner tubes for pneumatic motor tires. The 

 machine is on the three roller principle, viz.: with two bottom 

 fi.\ed rollers and one top adjustable rising and falling roller. 

 After the tube has been put on the mandril, a certain length 

 of cloth is wrapped evenly and straight on the tube by the 

 machine. The machine is then allowed to run for a certain 

 time, until the cloth is thoroughly stretched and levelled the 

 whole length of the tube. This manner of wrapping also en- 

 sures the tube being of equal thickness and of perfect vul- 



canization the entire length. The output of this machine 

 is referred to as being far in excess of the old method of hand 

 wrapping, besides doing its work far better. The pressure 

 is brought to bear on the surface of the material being wrap- 

 ped on the mandril b}- a foot rest running full length of roll- 

 ers in front of the machine. In con.sequence of the perfect 

 balancing arrangement of the top roller, which is fitted with 

 ball and roller bearings throughout, and the easy working 

 of the machine, it can be operated from any position in front 

 bj' the attendant quite easily, and anj- required pressure can 

 be brought to bear on the mandril. The top or pressure 

 roller is adjustable in every wa\' so as to get equal pressure 

 the full length of the rollers. [David Bridge & Co., Man- 

 chester, England.] 



MK. HOLLOWAY ON "LACE RUBBER." 



[from the " CEVI,ON OBSERVER."] 



T NOW have the pleasure of stating that the first consign- 

 ■*■ ment of " lace " rubber sent to Hamburg was sold at 14 

 marks per kilo, or as near as possible 6s. i%d., about the 

 highest price paid, during the same week, in London for bis- 

 cuits or sheet. Wlien you consider the fact that lace is ready 

 for packing in 48 hours, and that no expensive machinery is 

 required, no power to drive the machine as in the case of 

 crepe, which requires 8 or 9 HP. (whereas lace requires only 

 about ,'s HP.), besides the great saving in labor, the superi- 

 ority of manufacturing the rubber into the form of lace is 

 apparent. The brokers' report is as follows : " The rubber 

 is reported upon to be first class and is valued at 14 marks 

 per kilo, at which price the parcel has been sold." 



The brokers are all mad on sheet rubber just now ; but is 

 this practicable on a large estate, where a large acreage is in 

 bearing ? For it takes just as long to dry as biscuits, or in 

 fact longer ; consequently a very large drying space will be 

 required. FRANCIS J. holloway. 



