and 61 are also connected and further assuming that valve 50 has been actuated in a manner to provide pressure through line 52b and check valve 51 and a flow return passage through line 52a then fluid under pressure will be provided through line 57b to line 61 and this fluid under pressure will be provided through the internal check valves of integrator valve 65 through lines 66 and 67 to the base ends of cylinder 40a and 40b tending to lower the circle frame and cutting blade check valve 54 which is a pilot operated check valve will prevent reverse flow back to valve 53 inasmuch as no pilot pressure is supplied to the input of the check valve however return flow then must come from the rod ends of both cylinders through lines 63 and 64 to the inputs of the flow integrator valve 62 the flows from the two lines must be exactly equal or the flow integrator will adjust to restrict the largest flow to insure that the flows become equal the combined flows will be discharged through lines 60 57a and 52a the exhaust flows from both cylinders thus have to be equal meaning that the cylinders will have to move an equal amount the blade control is therefore precise operating the valve 50 in opposite direction will cause retraction of the.