330 



THE INDIA RUBBER WORLD 



[March I, 1917. 



reduces to a minimum the leverage so objectionable in the or- 

 dinary coupling. They are furnished in standard sizes, from % 

 to 500 horse power at 100 revolutions per minute. [Charles 

 Bond Co., Philadelphia, Pennsylvania.] 



MOTOR-DBIVEN VARIABLE SPEED DRIVE. 



Changes in speed are very necessary in a large number of 

 mechanically performed operations in rubber goods manufacture, 

 hence the demand for a progressive or variable speed changing 

 driver. In the larger and more modern mills, calenders are 

 invariably driven by motors provided with effective controllers 

 of the electrical type that provide a wide speed variation. There 

 are, moreover, many machines outside of the calender room 

 where varying speed conditions may be met in a satisfactory 

 manner by a motor-driven speed change device of the type 

 shown in the accompanying illustration. 



This device consists essentially of a pair of cone pulleys, over 

 which runs an ordinary leather belt. Under the belt the surface 

 of each cone is built up from conical to cylindrical form by a 

 patented cone pulley transformer. Each consists of a series of 

 tapering leather strips riveted to an endless belt, the strips being 

 so formed as to give a crown like that of an ordinary pulley. 



To effect a change of speed these transformers are shifted along 

 the cones, without stopping the machine, by a screw and chain, 

 as the illustration shows. 



While they are in contact with a cone they run exactly as if a 

 part of it. The angle of the cones is such that there is. no ten- 

 dency to slip or creep endwise. The belt may be of any desired 

 width up to the full width of the transformers. 



These speed changes are furnished complete in vertical or 

 horizontal countershaft types for floor or ceiling attachment, and 

 fiom 1 to 20O horse power. [The Moore & White Co., Phila- 

 delphia, Pennsylvania.] 



THE NEWAYGO MECHANICAL SCREEN. 



In the preparation of rubber dust and other finely divided 

 products used in the manufacture of hard rubber and composition 

 soles and heels, the mechanical screen plays an important part. 

 In some cases it is necessary to remove the fiber from the rubber. 

 In others, a certain portion of the fabric is retained in the finished 

 product, while in the case of hard rubber grinding, there is no 

 fiber to contend with. These variable conditions and final prod- 

 ucts are controlled by a mechanical screening process. 



The material is first broken down to about % to 14 inch on a 

 cracker and then passed through a 42-inch horizontal grinding 

 mill from which it is delivered to a screen that takes out the fiber 

 and the 40-mesh material. The tailings are then passed through 

 a second mill and over a second screen that removes the 40-mesh 

 material and completes the screen operation. 



The distribution of the feed over the entire width of the screen 

 cloth is effected by a screw conveyor and an adjustable feed 

 board at the top of the machine. The various products are taken 

 away at the bottom of the screen. These machines are constructed 

 with one, two and three screening surfaces and, therefore, can 

 deliver from one to four products from a single separator. 



Practically no power is required to drive them. In fact, 1 horse- 

 power runs the largest size. The capacity is very large as the 

 entire screening surface is in constant use and the meshes are 



kept open by mechanical vibration thus allowing the fine mateHal 

 to pass through the screen. 



It is practically dust-proof and fire-proof as practically no 

 wood is used in the construction. [Sturtevant Mill Co., Boston, 

 Massachusetts.] 



THE WOLF VACUUM STEAM DRYER. 



The process of drying reclaimed rubber and the elimination 

 of all moisture in the dry fillers and other materials used in 

 rubber manufacture is of well known importance to the trade. 

 The Wolf vacuum steam dryers are constructed in units and a 

 side elevation of the three-cylinder type is shown herewith. The 

 outer shells of the cylinders are covered with asbestos, while 

 the inner shells are machined and contain spiral conveyors of 

 the rubber type provided with unifying paddles at each flight. 

 Steam is piped to the chambers between the inner and outer 

 shells and an efficient steam trap removes the condensation. 



The material to be dried is delivered to the top cylinder in which 

 it is agitated continuously and conveyed in the same manner 

 through the succeeding chambers and finally discharged in a 

 uniformly dried condition. All gears are provided with gear 

 guards and the drive end is supported by outboard bearings. 

 [The Wolf Co., Chambersburg, Pennsylvania.] 



SPECIAL MACHINES. 



RUBBER AIDS IN UNHAIRING HIDES. 



""THE removal of hair from hides is an important process in 

 the tanning industry and one that at first thought would not 

 appear to be particularly difficult. Yet when a hide varies in 

 thickness from 3/16 to 9/16 of an inch the operation requires 

 considerable skill. For that reason experienced workmen with 

 special knives were formerly thought indispensable in removing 

 the hair without cutting the hides. 



When unhairing machines were first used the difficulty of allow- 

 ing for variations was apparent, the human element being 

 eliminated. Now it appears that rubber is called upon to replace 

 the hand workman's intelligence. Rubber rolls of soft vulcanized 



