Editing Caster (section)

=== Braking and locking casters ===
[[File:Swivel caster with wheel lock.JPG|thumb|A swivel caster with a wheel lock. The vertical swivel on this type of caster cannot be locked in position.]]
[[File:Caster - Central locking mechanism - Stryker hydraulic stretcher.JPG|thumb|Caster central locking mechanism on an old [[Stryker Corporation|Stryker]] hydraulic [[stretcher]]. Shown in the locked position with the center cam rotated downward.]]

Common inexpensive casters may include a [[brake]] feature, which prevents the wheel from turning. This is commonly achieved using a lever that presses a brake cam against the wheel. However a swivel caster is still able to move around slightly, in a small circle rotating around offset distance between the vertical shaft and the center of the locked wheel.

A more complex type of swivel caster, sometimes called a total lock caster, has an additional rotational lock on the vertical shaft so that neither shaft swiveling nor wheel rotation can occur, thus providing very rigid support. It is possible to use these two locks together or separately. If the vertical shaft is locked but the wheel can still turn, the caster becomes a directional caster, but one which may be locked to roll in one direction along any horizontal axis.

In some cases it is useful to be able to brake or lock all casters at the same time, without having to walk around to individually engage a mechanism on each one. This may be accomplished using a central lock mechanism engaged by a rigid ring encircling each swivel caster, slightly above the wheel, that lowers and presses down on the wheel, preventing both wheel and swivel rotation. An alternative method is the central lock caster, which has a rotating cam in the center of each vertical caster shaft, leading down to a braking mechanism in the bottom of each caster.