How Hydraulic Jacks Work

1. How Hydraulic Jacks Work Jacks are pieces of material handling equipment that uses force multiplication to lift or move heavy loads. The term jacks can refer to a variety of lifting devices that employ leverage and other methods of mechanical advantage to amplify an applied force to provide the ability to transport a load. Hydraulic jacks are distinguished by their use of an incompressible liquid, such as hydraulic fluid or jack oil, as the means by which force multiplication is achieved. Mechanical jacks, such as the commonly used car jacks, lift heavy equipment and are rated based on the lifting capacity, which is typically expressed in terms of the number of tons that the jack can handle. Hydraulic Jack Components and Nomenclature To illustrate the components that are used in a hydraulic jack, a typical manually operated hydraulic jack will be considered. The primary components are discussed below. • • • • • • • Reservoir or buffer tank Pump with piston or plunger Pump lever or handle Check valve Main cylinder or ram Release valve Handle

2. Types of Hydraulic Jacks Two common types of hydraulic jacks include bottle jacks and floor jacks. Bottle Jacks Bottle jacks became popular in the early 1900s when the automobile industry began to take off. Also called hand jacks, bottle jacks provided an easy way for an individual to lift a vehicle for roadside inspection or service. Although they are most commonly used in the automobile industry (1.5 to 5-ton jacks are the range of capacities typically used to lift cars), bottle jacks have other uses as well. In the medical industry, they can be used in hydraulic stretchers and patient lifts. Bottle jacks can be secured within a frame, mounted on a beam, or simply used as free-standing to allow for repositioning as needed. Floor Jacks What is a floor jack? Unlike bottle jack shafts which operate vertically, the shaft in a floor jack is horizontal—the shaft pushes on a crank that connects to a lifting pad, which is then lifted vertically. Although “mini jacks” are also produced, they are not a recognized standard type of floor jack. Typically, one of the first two sizes should be used. Applications for Jacks Jacks have wide applications in different industries and are used to lift and transport heavy loads, relieve vertical forces from weight-bearing members so repairs can be made, and are valuable pieces of equipment in the construction, shipbuilding, automotive repair, as well as other specialized industriesAircraft • • Automotive, such as for transmissions and engine testing Bridges

3. • • • • • • • • • • • • Cable tensioning Construction House moving General Industrial Laboratory Locomotive Marine Mobile Home Railroad Shipbuilding Shoring and stabilizing such as for tunnels and mines Tractors & Trailers