Jack (device)
From Wikipedia, the free encyclopedia
- For other uses, see jack or carjacking.
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 to allow a human to lift a vehicle. More powerful jacks use hydraulic power to provide more lift over greater distances. Mechanical jacks are usually rated for a maximum lifting capacity (for example, 1.5 tons or 3 tons).
[edit] 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 threaded rod is turned up with a metal rod. This piece tilts very slightly but not enough to render the post dangerously out of Plumb.
