Instrumentation & controls has introduced air hydraulic presses. These use the high power of hydraulics and low power high speeds of pneumatics. These are very economical presses for most applications where currently hand operated screw presses are used, to avoid manual fatigue and high labour cost, giving better production rate. These hydrolic presses have following construction features:
- include air operated hydro-pneumatic booster, oil tank with integral hydraulic and pneumatic cylinder and pneumatic control valves, all combined to form one unit.
- the hydro-pneumatic cylinder is placed on a four-column press body or a c-frame type press body or on standard screw press to convert it in air-hydraulic press.
- working/principle of operation: when air enters, pneumatic cylinder gives rapid approach stroke with low force. As ram [piston rod end] touches the job, the booster and hydraulic cylinder comes in action to give high force [2 tonnes to 50 tonnes as per model] using hydraulic pressure generated by booster by air pressure of 5 bar only. The ram returns at high speed with low force. It includes range of: 1 capacity: - 2 to 50 tonnes with strokes 50 to 150 mm; 2 daylight = 150 mm to 800 mm it requires air pressure of 7 bar. These are useful where initial stroke is at low force and only power force is required in last, eg, blanking, punching, bending, forging, coining, squeezing, riveting, deep drawing, etc.
