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Pressure Oil Units

  • Precision in operation owing to the pressure generating unit being a gear pump
  • Cylinders may be arranged in any required position
  • High reliability and durability
Picture Pressure Oil Units

KoRo IBS Pressure Oil Units

Pressure Oil Units

Pressure Oil Units
(PDF, 1.79 MB)


The pressure oil unit is an electro hydraulic drive consisting of pump and cylinder which are connected through a pressure hose and an oil leakage hose. The most important driving element of a pump is a gear pump driven by a standard type three-phase A.C. squirrel cage motor, through an elastic coupling. The pump also comprises an overpressure valve as well as a fully hydraulically-operated control valve. A big oil tank which forms at the same time the bottom of the pump stores and takes the required oil. This oil tank has feet for mounting purpose.

The actual working part is the cylinder. This cylinder contains the piston, the lifting power of which is transmitted by the piston rod. The cylinder normally has a built in pressure spring which is compressed after switching on the pressure oil pump. After switching off the spring power drives the piston back into its initial position. As the pressure oil units are often used as brake lifting units the said pull-back springs serve as brake spring at the same time. For this reason, they are dimensioned accordingly so as to meet the requirements of each special case, thus, the springs are adapted to the various brake disk diameters.

When the pump motor has been switched on, the gear pump immediately generates oil pressure. So the hydraulic control valve is operated and the oil pressure acts upon the piston of the cylinder, moving it into the highest possible position; thus, the PULL-BACK SPRING or BRAKE SPRING is compressed. As long as the pump motor remains in operation, the working piston is held in this highest position; the overpressure valve allows the pressure oil to circulate in the interior of the pump

After the pump motor has been switched off, the control valve causes the cylinder to be discharged immediately. Driven by the brake spring, the working piston is pushed back into its initial position. In case of a sudden failure of the electric current, the brake will be set automatically, for the braking pressure is always generated by the spring. Consequently, an additional spring or a braking weight is not required.

Application of Pressure Oil Units:

As brake lifting appliances for the release and setting of brakes of any type, such as crane brakes, brakes for elevators, excavators, roller adjustment, attachments, twisting machinery, conveyor equipment

  • For operation of pressing rollers, ratchet device and switches in rolling mill trains
  • For shifting mechanically acting clutch coupling
  • For closing or opening furnace doors (with long stroke pressure oil cylinders)
  • In shearing machines, for holding down the materials to be cut
  • As low capacity pressing cylinders
  • In slide valve gears of operating instruments, etc.
  • Highest working reliability owing to the simple and especially heavy construction
  • Precision in operation owing to the pressure generating unit being a gear pump (compression principle)
  • Shock free operation owing to a hydraulic shock absorber, insignificant wear of brake linings
  • Universal range of application owing to the fact that cylinders may be arranged in any required position
  • One pump only is capable of driving several cylinders
  • The pressure (power) produced by the piston is considerably higher than that of the spring
  • Long operation life – pumps and cylinders of the 50es are still being repaired today and are used again. Spare parts available after more than 50 years

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