Stabilizer jacks are devices used in recreational vehicles and caper trailers to support the floor and keep it rigid when in use and prevent the RV or trailer from tipping. They are generally made of aluminum or steel and use a screw or spring mechanism for lowering and lifting.
Stabilizer jacks may be the traditional scissor-type jacks that require a crank or lever to lower and raise, although some newer jacks have motors and operate electronically and raise and lower raised or lowered at the touch of a button. The jacks are permanently mounted on most large trailers, but are portable on smaller recreational trailers.
Stabilizing jacks may also be used with commercial trucks. A trucker may use stabilizer jacks to keep a semitrailer and its contents in an upright position when not attached to a tractor, or to prevent the semitrailer from up-ending during loading and unloading operations. Stabilizer jacks also keep trailers that are parked on inclines or slopes level and keep landing equipment from sinking into muddy or softened ground.