GLOSSARY OF TERMS

Accumulator:
A device which stores hydraulic oil under pressure. It is used to maintain system pressure so that a palletized fixture can be isolated from its power source. It can also compensate for minor leakages within the system.

Check Valve:
An in-line valve which permits flow in one direction only.

Clamping Force:
This is the product of the hydraulic pressure (in pounds per square inch) multiplied by the cylinder bore area of the clamp (in square inches). The units of force are pounds. Force can be applied as a push or pull.

Displacement:
The volume of oil required to extend a cylinder rod. The displacement of a double-acting cylinder is the total volume of oil to extend and retract the cylinder rod. It is calculated by multiplying the cylinder bore area (in square inches) times the stroke or travel of the rod (or plunger) (in inches). The units of displacement are cubic inches.

Double-Acting Cylinder:
A cylinder which utilizes fluid pressure to extend and retract the rod (or plunger). This cylinder requires a 4-way valve and is usually powered by a pump. If air can be used to retract the cylinder, then a booster could be used as a power source.

Electric Valve:
A valve operated by a solenoid.

Flow control Valve:
A valve with an adjustable flow area (usually a tapered needle and seat) so the the flow rate of oil van be regulated. It is usually used to slowdown, or sequence, the movement of an actuator.

Hydraulic Power Source:
A booster or pump and it's components used to develop hydraulic pressure in a clamping system.

Hydraulic Pressure:
Mathematically defined as the force required (or applied) to hold (clamp) a part divided by the cylinder bore area. Stated generally, it is the force per unit area. Units are usually in pounds per square inch. If more than one clamp is used, the force should be divided by the number of clamps used before determining system pressure required.

Manifold:
A machined block which provides multiple ports to connect a power source to multiple clamping actuators.

Pascal's Law:
The pressure in a confined fluid at rest is constant throughout the fluid.

Popper Valve:
A valve which limits maximum system pressure. It is usually adjustable to a predetermined value.

Swing-Acting Cylinder:
A cylinder which utilizes fluid pressure to extend the rod (or plunger). Retracting force is provided by a spring. This cylinder can be powered by a pump or a booster, and is sometimes called a swing-return cylinder.

Stroke:
The linear distance the cylinder rod or plunger travels, (in inches).

Valve:
A device for controlling the direction, pressure, or flow rate of a hydraulic fluid.