ISO 



THE INDIA RUBBER WORLD 



December 1, 1920 



The rubber is thus forced into the recesses of the scroll with a 

 constant and positive feed and is prevented from encircling the 

 feed roller by the action of a scraper located adjustably as a 

 part of the device. 



The feed roller revolves in contact with the scroll and is driven 

 from the scroll shaft through machine cut spur >;earing. Tubers 

 with this type of roller feed are the special design and product 

 of Francis Shaw & Co., Limited, Manchester, England. 



DOGWOOD DIE BLOCKS FOR RUBBER FACTORIES 



Wooden blocks are largely used in the manufacturing of 

 rubber goods where the material is cut by means of knives or 

 dies, such as in footwear, rubber sole and heel, and rubber 

 mat factories. These blocks are usually of maple, although 

 lately fiber blocks have been substituted with good results. 

 Better than either, so the maker claims, is a block made of dog- 

 wood (Conius l-lorida), selected from the finest growths of 

 Texas or Virginia. A dogwood block is much harder than one 

 of maple, closer-grained and has less tendency to warp. It has no 

 grit to dull the die, and does not break up into sawdust as 

 does maple. Its lasting qualities are more marked, as only J^-inch 

 IS planed from a dogwood block as against '4 inch from a 

 maple block. Its use enables a workman who cuts by hand to 

 do with a three-pound mallet the same work that formerly re- 

 quired a ten-pound mallet, .\fter competition tests with fiber 

 cutting blocks in one of the mills of a large rubber company, the 

 dogwood block was given preference, the price of the two blocks 

 being about the same. — Shambow Shuttle Company, Woonsocket, 

 Rhode Island. 



MACHINERY PATENTS 



PNEUMATIC TIRE REMOVING APPARATUS 



THIS is a machine designed to remove heavy pneumatic truck 

 tires without injury to the rim, and to replace the slow 

 manual methods heretofore used. Referring to Fig. 1, the upper 

 drawing is a sectional elevation with a tire in position on the 

 machine, while the lower is a plan view. 



The tire B is placed on top of the annular e.xpansion chamber 

 A. The arms of the spider C are rested on the upper edge of 

 the rigid metal tire rim. Then the spider is secured in posi- 

 tion by screwing down the nut on the bolt which extends from 

 the table top upward through the spider hub. 



Compressed air is admitted into the inner tube of the e.Kpan- 

 sion chamber A through a nipple attached to a branch of the 

 tube, which extends down below the table. The gradual infla- 

 tion of the tube causes the expansion chamber A to expand, and 

 in turn raise the tire upward until it slides up over the outer 

 face of the rim. A relatively low air pressure in the tube inside 

 the expansion chamber is sufficient to exert a large force on 

 the tire.— Noah L. Caldwell, Knoxville, Tennessee. United 

 States patent \o. 1,352,722. 



VULCANIZING RUBBER TIRES BY ELECTRICITY 



The object of this invention is to use electricity instead of 

 steam as the medium of vulcanizing rubber tires, in a simple, 

 economical and efficient manner. 



The apparatus shown in plan and elevation in l-"ig. 2 consists 

 of a tire mold, preferably of metal and formed in halves, which 

 are fastened together by bolts. The rubber tire on its core 

 is placed in the mold. The casing thus made up forms a con- 

 tinuous metal ring shown at A. This ring becomes a single 

 turn secondary coil of a transformer, the primary coil of which 

 is B and the transformer core C. This is made up in the usual 

 manner of laminated sheet iron, and it is comprised of two 

 parts, which are readily separated, as indicated by the dotted 

 lines, allowing the tire mold to be easily removed. The primary 

 coil B of the transformer may he divided into any desired 



number of sections with leads, D to allow a wide range of heat 

 control. 



The tire mold is made up and inserted into the core of the 

 transformer, which is then closed to its normal position. Cur- 

 rent is supplied to the primary coil of the transformer, and a 

 current of low voltage, but relatively high in amperes is induced 

 into the tire mold. Due to the resistance offered to the flow 

 of current, by the metal, the mold quickly becomes heated and 

 the tire is vulcanized. The intensity of the heat is easily con- 

 trolled by the number and the mode of connections of the sec- 

 tions of the primary coil. — Joseph Ledwinka, assignor to Edward 

 G. Budd Manufacturing Co., both of Philadelphia, Pennsylvania. 

 United States patent No. 1,348,228. 



MACHINE FOR CUTTING RINGS AND WASHERS FROM TUBING 



This improved device for cutting rubber packing rings or 

 washers from tubing, works satisfactorily upon thick material 

 necessary to produce wide rings. 



Referring to Fig. 3, which shows a plan of the machine, the 

 tubing is placed on a mandrel A, which is held l>etween centers 

 and driven by the belt pulley B. 



The cutter head C has a number of spaced knives, and it is 

 mounted on a shaft with a spur gear at one end. which meshes 

 with a smaller gear at the end of the shaft supporting the 

 mandrel. Each blade on the cutter head is spaced from the pre- 

 ceding blade a distance corresponding to the desired tliickness of 

 the packing rings. The blades project sufficiently to cut com- 

 pletely through the rubber tubing, the knives acting succes- 

 sively, due to the fact that the mandrel rotates faster than the 

 cutter head. 



Where long tubing is used, the cutter head may be intermit- 

 tently moved after the cutting of one set of rings. This is done 

 by leaving a gap in the knives, so that the knives are all out of 



Fig.2 

 Electric Tire Vulcaniier 



Fig] Truck Tire Removing Press 



Fig. J Ring and Washer Cutter 



contact with the rubber tubing until the shifting of the cutter 

 head is completed.— Joseph E. Perrault, assignor to Hood Rubber 

 Co., both of Watertown, Massachusetts. United States patent 

 No. 1,348,316. 



PRODUCING A HOLLOW RUBBER BISCUIT 

 This invention covers the process and apparatus for producing 

 an inflated rubber article known as a biscuit, from which bulbs, 

 toys and similar blown goods may be made. 



