14 LEATHER BELTING 



and the range of speed of the cone belts was from 225 to 1340 

 ft. per minute. 



Factors which Influence Life of Belts. A study of the 

 table on pages 12-13 w iU show an immense superiority of 

 the shifting belts over the cone belts in every item excepting 

 the first cost. This superiority is greater than the figures 

 indicate, because as a rule the cone belts in use at the time the 

 table was published were nearly worn out, while the shifting 

 belts were in as good condition as when they were put into 

 service. Mr. Taylor drew the conclusion that the life of 

 the shifting belts would be three times that of the cone belts, 

 and at the time of the publication of the table the total cost 

 of the shifting belts per year of service was lower than that 

 of the cone belts. 



According to Mr. Taylor, the items which chiefly affect the 

 life and satisfactory running of belting are as follows : 



1. The material from which belts are made and the method 



of their construction. 



2. Means of fastening and tightening them on the pulleys; 



i.e., whether laced, spliced or fastened with hooks. 



3. The care and regularity with which they are greased 



and whether they are kept clean and free from oil. 



4. The general nature of the services which belts are called 



upon to perform. 



5. Whether belts run vertically or horizontally. 



6. The relative length of the belts. 



7. The relative speed of the belts. 



8. The tension under which they are tightened. 



9. The average total load to which they are subjected 



while working. 



The eighth and ninth elements undoubtedly are those 

 which have the greatest influence upon the life of belts. 

 While all belts, both shifting and cone, were tightened to the 

 same initial tension of 71 Ib. per inch of width or 239 Ib. per 

 square inch of section, the shifting belts were, as a result of 



