edgepedia

Fluid power, actuation, and mechanisms

90 articles

Pneumatics

Pneumatics is the branch of fluid power in which a gas, almost always compressed air, transmits and controls energy, flowing from compressors through valves to actuators that produce motion.

Power take-off

A power take-off (PTO) is a splined output shaft, usually at the rear of a tractor or truck gearbox, that transfers engine power to driven implements.

Pressure compensator

A pressure compensator is a hydraulic control element that adjusts pump displacement or valve pressure drop to keep flow or pressure constant under changing loads.

Proportional valve

A proportional valve is an electro-hydraulic or electro-pneumatic valve whose control element moves continuously in proportion to an electrical input signal, allowing stepless flow and pressure regulation.

Pump sump

A pump sump is the reservoir, or lower portion of a wet well, from which a pump draws water, designed to deliver steady, swirl-free flow to the pump suction inlet.

Reciprocating saw

A reciprocating saw, often called a Sawzall or recip saw, is a handheld power saw that cuts wood, metal, and plastic with a rapid back-and-forth blade stroke.

Roller screw

A roller screw is a mechanical transmission that converts rotary motion into linear motion using rollers rolling between a screw shaft and a nut, carrying about three times the load of a ball screw.

Rotary actuator

A rotary actuator is a device that converts hydraulic, pneumatic, or electrical energy into controlled rotary motion, usually limited to one revolution, serving valve automation and robotics.

Rotary vane pump

A rotary vane pump (vane pump) is a positive-displacement pump with a slotted eccentric rotor whose sliding vanes trap fluid and compress it from inlet to outlet.

Rotary-screw compressor

A rotary-screw compressor, also called a screw compressor, is a positive-displacement compressor that compresses gas between two intermeshing helical rotors in a machined housing, dominating industrial air compression and refrigerant use.

Rube Goldberg machine

A Rube Goldberg machine is a chain-reaction contraption that performs a simple task in an indirect, overly complicated way, named after the American cartoonist Rube Goldberg.

Scotch yoke

The Scotch yoke is a mechanism that converts rotation into reciprocating linear motion, producing exact simple harmonic motion from a crank pin sliding in a slot.

Screw pump

A screw pump is a rotary positive-displacement pump that moves fluid through sealed cavities created by helical rotors, a design attributed to Archimedes of Syracuse.

Servo valve

A servo valve is an electrohydraulic valve that converts an electrical input signal into precise, stepless hydraulic flow or pressure, used in aircraft flight controls, test rigs, and steel mills.

Servomechanism

A servomechanism, or servo, is a feedback control system whose output is mechanical motion, typically the position or speed of a shaft, driven by an error signal.

Sewage pump

A sewage pump is a pump that moves raw wastewater containing solids, rags, and grit from lower to higher elevation, typically from a wet well into a pressurized force main.

Slurry pump

A slurry pump, also known as a lined pump or dredge pump, is a heavy-duty centrifugal pump that transports abrasive slurries in mining and dredging.

Specific speed

Specific speed is a characteristic index number for rotodynamic pumps that condenses best-efficiency speed, flow, and head into one value for comparing and classifying impellers.

Spool valve

A spool valve is a directional control valve in which a cylindrical spool with lands and grooves slides axially in a bore to open, close, and redirect flow.

Suction cup

A suction cup is a flexible, cup-shaped element that grips a surface by atmospheric pressure when the air inside is removed, powering industrial vacuum lifters and everyday holders.

Surge line

The surge line is the boundary on a compressor's performance map that separates stable operation from surge, an unstable condition in which flow reverses and pressure fluctuates cyclically.

Swashplate (mechanism)

A swashplate is a disk mounted at an angle on a rotating shaft to convert between rotary and axial reciprocating motion, most commonly in variable displacement axial piston pumps.

Torque converter

A torque converter is a fluid coupling placed between an engine and an automatic transmission, transmitting power through circulating fluid, allowing slip, and multiplying torque at low speeds.

Turbine pump

A turbine pump, usually the deep-well vertical type, is a centrifugal pump whose impellers sit in diffuser bowls down the well while a surface motor drives them.

Type synthesis (mechanism design)

Type synthesis is the mechanism design stage that generates and selects a mechanism's structural type, its topology of links and joints, to produce a prescribed motion, preceding dimensional synthesis.

Universal joint

A universal joint, also called a Cardan joint or Hooke joint, is a coupling that transmits rotation and torque between shafts meeting at an angle, typically 0 to 45 degrees.

Variable displacement pump

A variable displacement pump is a positive-displacement pump whose displacement can be changed while operating, so output flow matches demand without throttling losses, mainly in hydraulic systems like mobile machinery.

Volute (pump)

A volute is the spiral-shaped casing of a centrifugal pump, converting the impeller's velocity head into static pressure while guiding the liquid to the discharge nozzle.

Waterbomb origami

Waterbomb origami is a traditional Japanese pattern, known as the water balloon, whose crease geometry is one of the most widely used patterns in engineering origami.

Whitworth quick-return mechanism

The Whitworth quick-return mechanism is a planar linkage converting constant crank rotation into reciprocating motion with a slow cutting stroke and fast return, used in shapers and slotters.