Question: The cylinder in the circuit shown in Fig. has a resistive load for the first 20 in. of the extension stroke and an overrunning load for the second 20 in. of the extension stroke. The cylinder bore is 3.25 in., the rod diameter is 2 in., and the friction force is 93 lbf. Maximum overrunning load is estimated to be 4380 lbf . The counterbalance valve is set such that the pump must develop at least 25 psi of cap-end pressure before the cylinder will extend the final 20 in. and lower the overrunning load to a safe stop. The relief valve is set on 3000 psi. For this problem, neglect all pressure drops in the lines.
1. Find the pressure setting needed for the counterbalance valve.
2. Calculate the maximum resistive load when the cylinder is extending.
