THE SPRING CLUTCH 741 



Conclusion 



The relations developed in the preceding sections are sufficient to 

 determine uniquely the correct spring dimensions for a spring clutch 

 of specified free and gripping torque provided the material constants 

 and the cross-sectional shape (round or rectangular) of the wire, as well 

 as the length and diameter of the clutch arbor, are specified. Choice 

 of values for the last two factors is based largely on permissible heating 

 resulting from the slipping in the free direction. Furthermore, as 

 would generally be the case, if only maximum values of the free torque 

 and minimum values of the gripping torque are given a number of 

 solutions can be obtained from which to choose the most convenient. 

 By combining the relations derived, in a manner to permit step-by-step 

 calculation, the design of spring clutches is reduced to a simple routine. 



