A caster where the swiveling portion is internal. There are two vertically disposed, horizontally spaced-apart rollers located on a horizontal roller axle mounted in a yoke attached to the bottom of a central shaft. The central shaft has two bearings supporting it with two central core spacers. The spacers on the inside diameters of the bearings have angled holes that are offset by 180 degrees.
The inner central shaft lies in a vertical plane which is centered on the caster but the center line of the center line of the inner central shaft is angled with respect to the center line of the device. This allows the shaft and spacers to rotate if the ball tries to roll in any direction such that the internal rollers align themselves with the direction of roll.
Below the rollers is the main rolling ball. This can be made of different materials as dictated by the use. For example; hard rubber for most applications, soft rubber for softer ride, air inflated for very soft ride. The balls could be interchangeable. A Teflon or suitably slippery area at the lower extremity of the outer casing reduces friction between the ball and the outer container. Snap rings prevent the ball from falling out if the device is lifted off the surface.
The whole caster can be placed inside a second container. The two canisters would be held apart by a foot activated cam that raises and lowers the outer canister to allow the outer can to contact the surface and lock the device in place by taking the load off the ball. Alternately, the caster can be raised and lower in the leg of the supported device.
- No external moving parts.
- Clean visuals; esthetically.
- Center of Gravity and associated stability do not change.
- Less danger of tip over since the load remains directly over the central axis of the ball.
- Foot lock is consistently stable with respect to tip since the support center line does not change.
- Inexpensive versions are possible where the ball bearings are replaced with injection molded bushings and/or made entirely of plastic.
- Replaceable balls are changeable for differing surfaces and vibration isolation requirements or different ride quality.
? e.g. air filled, steel, hard plastic, soft plastic, rubber
- Scalable to very small or very large sizes.
- Eliminates “shimmy” that is typical of conventional casters
- Potential for internal dirt entrapment is reduced by the Teflon and snap rings above and below the ball that act as scrapers to remove excess dirt as the ball rolls.
- Ball can be cleaned by driving over a floor wetted with cleaner, anti bacterial agent or bleach.
- Internal cavity can be loaded with antibacterial grease.
- Larger bearing/contact area of a ball (circular as compared to narrow rectangular contact area of a wheel, does not penetrate as far into a soft surface or elevator door spaces making it easier to roll.