Kingpin vs. Kingpinless Swivel Casters

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By Edwin Rodriguez
Creative Director
Categories: Casters
March 5, 2014

One of the many design variables when considering the best solution for your heavy duty industrial caster application is whether to include a kingpin vs. kingpinless swivel caster construction.

Kingpin Construction:

A stem, typically a threaded bolt with slotted nut or sometimes a rivet is used to fasten the components of the swivel section to the top plate. The swivel action is centered about the kingpin. The kingpin design utilizes a load bearing and thrust bearing to transmit the load.

Advantages:

• The kingpin allows for adjustment as the swivel section wears, which can extend the life of the caster.
• Tightening of the kingpin nut creates resistance to the swivel motion, helpful when the caster is moving down an incline or at a high rate of speed (in excess of normal waking speeds).
• Control of flutter conditions. Flutter can occur when a swivel caster loses contact and orientation with the floor or ground, more common in higher speed applications or when the floor/ground surface is rough. When contact is made again, the caster may be in the right direction, causing a lurching motion of the caster and its load, possibly resulting in a major mishap or even injury.

Disadvantages:

Thrust loads of the caster are transmitted through the kingpin, making it a vulnerable failure point for the caster. The kingpin could become fatigued, distorted, or even sheared off. Kingpin constructed casters are normally not used for higher loads, higher impact, and higher speed applications.

“Kingpinless” Construction:

A kingpinless swivel section has fewer components, a top plate with a ball race, a yoke base (bottom race, and ball bearings.

Advantages:

• The kingpin is eliminated and any failure associated with a kingpin is avoided.
•  The caster load is spread over a larger area, allowing it to be used at higher speeds.
• The swivel motion is more uniform and swivels more easily.
• Less maintenance is required as there is no nut to be re-tightened.

Disadvantages:

Adjusting the swivel motion of the caster becomes much more difficult. Once the swivel raceways have worn, there is no way to adjust for this wear.

Kingpin vs. Kingpinless Swivel Casters Summary:

Both designs have their pros/cons.  It is important to have a full understanding of the caster’s intended application including loading conditions, speeds, duty cycles, floor/ground conditions, and other environmental concerns. We encourage you to contact our applications staff at customercentral@casterconcepts.com when making your caster selection.