Two working position pressure bar fatigue tester for dynamic test of pressure bar, pressure bar cycle life test. Air pressure bar dynamic test frequency 8/min ~ 12 / min; Pressure bar cycle life test6x10⁴; Test the opening force and starting force of the pressure rod, the stretching force and compression force at point C F₁F₂F₃F₄, calculate the nominal force, dynamic friction force and elastic ratio of the pressure rod, and draw the force-displacement curve.