(Solved):   \( 0-26 \) A static service music wire helical compression spring is needed to support a 2 ...

 

\( 0-26 \) A static service music wire helical compression spring is needed to support a 20 -lbf load after being compressed 2 in. The solid height of the spring cannot exceed \( 1 \frac{1}{2} \) in. The free length must not exceed 4 in. The static factor of safety must equal or exceed 1.2. For robust linearity use a fractional overrun to closure \( \xi \) of \( 0.15 \). There are two springs to be designed. Start with a wire diameter of \( 0.075 \) in. (a) The spring must operate over a \( \frac{3}{4} \)-in rod. A \( 0.050 \)-in diametral clearance allowance should be adequate to avoid interference between the rod and the spring due to out-of-round coils. Design the spring. (b) The spring must operate in a 1-in-diameter hole. A 0.050-in diametral clearance allowance should be adequate to avoid interference between the spring and the hole due to swelling of the spring diameter as the spring is compressed and outof-round coils. Design the spring.