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A portable machine, variously constructed, for raising great weights.

Jack

A portable machine, variously constructed, for raising great weights.

Instrument to pull off boots; a boot-jack

Jack

Instrument to pull off boots; a boot-jack

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

Jack Device Used for Lifting Objects

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

"Planes are to be met with in great variety, the most usual for ordinary carpentry being the jack plane." — Encyclopedia Britannica, 1893

Jack Plane

"Planes are to be met with in great variety, the most usual for ordinary carpentry being the jack plane."…

"In this family the arms appear to be merely prolongations of the disc; they are suaully five in number, and the plates from which the ambulacra are exserted are placed in deep furrows, which run along the lower surface of the arms." — Goodrich, 1859

Five-fingered jack

"In this family the arms appear to be merely prolongations of the disc; they are suaully five in number,…

This jack is used to lift heavy loads by applying great forces.

Lifting Jack

This jack is used to lift heavy loads by applying great forces.

Tool for exerting pressure or lifting

Lifting Jack

Tool for exerting pressure or lifting

Type of portable scaffolding system. The scaffold rests on supports attached to 2 or more horizontal posts. The user raises the scaffolding by pumping the foot pedals on the supports. Used in construction.

Pump Jack

Type of portable scaffolding system. The scaffold rests on supports attached to 2 or more horizontal…

"The jack-boot is almost entitled to be called the parent of the top and some other varieties. B. with tops of a yellow color were so commonly worn by gentlemen in the 18th century, as to become a peculiarity in the national costume of the English." — Chambers, 1881

Jack-boot

"The jack-boot is almost entitled to be called the parent of the top and some other varieties. B. with…

"An apparatus for lifting heavy bodies a short distance." — Williams, 1889

Screw-jack

"An apparatus for lifting heavy bodies a short distance." — Williams, 1889

"A machine for turning a roasting-spit by means of a fly-wheel or -wheels, set in motion by the current of ascending air in a chimney. a,a, the chimney, contracted in a circular form; b, strong bar placed over the fireplace, to support the jack; c, wheel with vanes radiating from its center, set in motion by the ascent of the heated air, and communicating by the pinion d and the crown-wheel e, with the pulley f, from which motion is transmitted to the spit by the chain passing over it." —Whitney, 1889

Smoke-Jack Used for Roasting Meat

"A machine for turning a roasting-spit by means of a fly-wheel or -wheels, set in motion by the current…

"Interior mechanism of a spinet. A, Jack; B, tongue; C, quill; D, bristle; E, cloth damper; F, pivot; G, wire."—Finley, 1917

Interior mechanism of a spinet

"Interior mechanism of a spinet. A, Jack; B, tongue; C, quill; D, bristle; E, cloth damper; F, pivot;…