Jack (mechanical)

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Jack (mechanical)

A jack is mechanical device used to lift heavy loads or apply great forces. Jacks employ a screw thread

Screw thread

A screw thread is a helix structure used to convert between rotational and linear movement or force.A screw thread may be thought of as an inclined plane wrapped around a cylinder or cone ....
or hydraulic cylinder

Hydraulic cylinder

A Hydraulic cylinder is a mechanical actuator that is used to give a linear force through a linear stroke. It has many applications, notably in engineering vehicles....
to apply very high linear forces.

>mechanical jack is a device which lifts heavy equipment.

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Mechanical jack

A mechanical jack is a device which lifts heavy equipment. The most common form is a car jack, floor jack or garage jack which lifts vehicles so that maintenance can be performed. Car jacks usually use mechanical advantage

Mechanical advantage

In physics and engineering, mechanical advantage is the factor by which a mechanism multiplies the force or torque put into it. Generally, the mechanical advantage is calculated as follows:...
to allow a human to lift a vehicle by manual force alone. More powerful jacks use hydraulic power

Hydraulic machinery

Hydraulic machinery are machines and tools which use fluid power to do work. Engineering vehicle is a common example.In this type of machine, high-pressure liquid ? called hydraulic fluid ? is transmitted throughout the machine to various hydraulic motors and hydraulic cylinders....
to provide more lift over greater distances. Mechanical jacks are usually rated for a maximum lifting capacity (for example, 1.5 ton

Ton

Units of massThere are several similar units of mass or volume called the ton:Others*The long ton is used for petroleum products such as aviation fuel....
s or 3 tons). The jack shown at the right is made for a modern vehicle and the notch fits into a hard point on a unit body

Monocoque

Monocoque, from Greek language for single and French for shell , is a construction technique that supports structural load by using an object's external skin as opposed to using an internal frame or truss that is then covered with a non-load-bearing skin....
. Earlier versions have a platform to lift on the vehicles' frame or axle.

Hydraulic jack

A hydraulic jack uses a fluid, which is incompressible, that is forced into a cylinder by a pump plunger. Oil is used since it is self lubricating and stable. When the plunger pulls back, it draws oil out of the reservoir through a suction check valve into the pump chamber. When the plunger moves forward, it pushes the oil through a discharge check valve into the cylinder. The suction valve ball is within the chamber and opens with each draw of the plunger. The discharge valve ball is outside the chamber and opens when the oil is pushed into the cylinder. At this point the suction ball within the chamber is forced shut and oil pressure builds in the cylinder.

House jack

A House jack is a mechanical device primarily used to lift houses from their foundation. A series of jacks are used and then wood cribbing temporarily supports the structure. This process is repeated until the desired height is reached. The house jack can be used for jacking carrying beams that have settled or for installing new structural beams. On the top of the jack is a cast iron circular pad that the 4" X 4" post is resting on. This pad moves independently of the house jack so that it does not turn as the acme-threaded

Acme thread form

The Acme thread form is a common leadscrew screw thread profile that offers high strength with ease of manufacture. It is typically found where large loads or high accuracy are required, as in a Vise or the lead screw of a lathe....
rod is turned up with a metal rod. This piece tilts very slightly but not enough to render the post dangerously out of plumb

Plumb

Plumb may refer to:* Plumb-bob, a type of tool* Plumb , a Contemporary Christian singer/songwriter* Plumbing* Plumb, to measure the depth of water with a sounding line...
.

Strand jack

A strand jack

Strand jack

Strand jacks are jack used to lift very heavy loads for construction and engineering purposes. Capable of lifting loads of over 1,000 tons, strand jacks were invented in Europe in the 1970s....
is a sophisticated hydraulic jack that grips and lifts steel cables; often used in concert, strand jacks can lift hundreds of tons and are used in engineering and construction.

Smoke jack

A smoke jack

Smoke jack

A smoke-jack is a Jack which gets its energy from a column of rising air or smoke. It is typically used to turn a Rotisserie in a cooking fire....
is a jack which gets its energy from a column of rising air or smoke. It is typically used to turn a spit

Rotisserie

Rotisserie is a style of roasting where meat is skewered on a spit - a long solid rod used to hold food while it is being cooked over a fire in a fireplace or Cooking on a campfire, or roasted in an oven....
in a cooking fire. It is considered an early example of a steam turbine

Steam turbine

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Charles Algernon Parsons in 1884....
and steam engine

Steam engine

File:Steam-powered fire engine.jpgA steam engine is a heat engine that performs mechanical work using steam as its working fluid.Steam engines have a long history, going back at least 2000 years....
.

Smoke-jacks were first described by Taqi al-Din

Taqi al-Din

Taqi al-Din Muhammad ibn Ma'ruf al-Shami al-Asadi was a major Ottoman Turks or Arab Muslim polymath: a Islamic science, Islamic astronomy and Islamic astrology, Timeline of Muslim scientists and engineers and Inventions in the Muslim world, clockmaker and watchmaker, Islamic physics and Islamic mathematics, Muslim Agricultural Revolution, I...
in his Al-Turuq al-samiyya fi al-alat al-ruhaniyya (The Sublime Methods of Spiritual Machines, 1551) and by John Wilkins

John Wilkins

John Wilkins was an Anglican ministry and author. He was founder and first secretary of the Royal Society in 1660 and Bishop of Chester from 1668 until his death....
in his Mathematical Magick (1648).