hydraulic press

hydraulic press

Machine consisting of a cylinder fitted with a piston (see piston and cylinder) that uses liquid under pressure to exert a compressive force upon a stationary anvil or baseplate. The liquid is forced into the cylinder by a pump. The hydraulic press is widely used in industry for forming metals and for other tasks where a large force is required. It is manufactured in a wide variety of styles and sizes and in capacities ranging from 1 ton (0.9 metric ton) or less to 10,000 tons (9,000 metric tons) or more. See also punch press.

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hydraulic press [hi′drȯ·lik ′pres]

(mechanical engineering)

A combination of a large and a small cylinder connected by a pipe and filled with a fluid so that the fluid pressure created by a small force acting on the small-cylinder piston will result in a large force on the large piston. Also known as hydrostatic press.

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Hydraulic press

A combination of a large and a small cylinder connected by a pipe and filled with a fluid so that the pressure created in the fluid by a small force acting on the piston in the small cylinder will result in a large force on the large piston. The operation depends upon Pascal's principle, which states that when a liquid is at rest the addition of a pressure (force per unit area) at one point results in an identical increase in pressure at all points.

The principle of the hydraulic press is used in lift jacks, earth-moving machines, and metal-forming presses (see illustration). A comparatively small supply pump creates pressure in the hydraulic fluid. The fluid then acts on a substantially larger piston to produce the action force. Heavy objects are accurately weighed on hydraulic scales in which precision-ground pistons introduce negligible friction. See Mechanical advantage, Simple machine