326 



AGRICULTURAL ENGINEERING 



Fig. 



210. Friction 

 gearing. 



where H. P. is the horsepower transmitted, D is the diameter of the 

 shafting, and R is the number of revolutions per minute. 



The above formula is for cold rolled steel shafting, the 

 kind in general use. 



QUESTIONS 



1. Why is a study of the transmission of power 

 an important feature of the study of machinery? 



2. How is power transmitted by a belt? 



3. What is meant by "tight" and "slack" 

 sides of the belt? 



4. Give the formula for estimating the horse- 

 power capacity of a leather belt. 



5. For what conditions of service is leather 

 belting adapted? 



6. Describe the care of leather belts. 



7. For what kind of service is rubber belting best? Canvas? 



8. Explain how a belt should be laced. 



9. Describe the various kinds of pulleys in general use. 



10. Why are some pulleys crowned? 



11. Explain how the rotative speed of one pulley may be obtained 

 from another. 



12. Where may link belting be used to good 

 advantage? 



13. What kinds of ropes are used in rope 

 transmission? 



14. Under what conditions should 

 rope or cable be used? 



15. How may triangles be used to transmit windmill power? 



16. What is the difference between cut and cast gears? 



17. Describe the construction ^ and action of spur gearing. 



18. Give the formula for the horsepower capacity of shafting 



a wire 



Fig. 211. A link belt 

 or chain transmissions. 



