When designing a heavy-duty industrial caster there are two main designs for the swivel section of the caster: Kingpin and Kingpinless. Both designs have advantages and disadvantages, and which one works best for you depends on your application.
The kingpin swivel section is one of the oldest methods for creating a caster swivel section. It utilizes a stem (sometimes a rivet or bolt) on the top plate to fasten together the lower part of the swivel section.
The kingpin design utilizes a load bearing as well as a thrust bearing to transmit the load. A threaded kingpin and a slotted nut design are the most standard configuration in heavy-duty industrial swivel casters and are what we reference in this blog. Is a kingpin design right for your application? Let’s take a look at the pros and cons of this design:
Kingpin Advantages: The threaded kingpin allows you to tighten the kingpin for varying levels of swivel resistance.
In certain situations, such as a heavy load situated on an incline, it is preferable that your caster doesn’t swivel easily. A kingpin caster allows you to tighten the nut to a larger torque value to decrease the swivel ability. The threaded kingpin-nut design also allows you to adjust the kingpin nut as the swivel section wears, which can prolong the life of the caster. This also allows the user easier access to clean out the swivel section if needed.
Kingpin Disadvantages: Due to most of the thrust loads being transmitted through the kingpin, it often becomes a failure point of the caster.
For this reason, kingpin casters are usually not recommended for high-speed towing applications. The high loads associated with turning at high speeds can greatly reduce the capacity of a kingpin style swivel section.
If a kingpin is improperly designed, it can also shear off under load causing complete caster failure. When designing an application using kingpin swivel casters, using the proper kingpin caster is absolutely critical.
The kingpinless design caster swivel section has only three components: a top plate with ball race, a yoke base (bottom race) with ball race and ball bearings. This design is similar to what one would find in a ball bearing. This design eliminates the kingpin and utilizes the swivel bearings to spread the load our over a larger area. The swivel section design also provides a more easily swiveling industrial caster.
Kingpinless Advantages: Since this design distributes the load out over a larger area, it can be used in higher speed caster applications.
The kingpinless swivel section also swivels more easily and requires less maintenance since there is no nut that needs to be retightened.
Kingpinless Disadvantages: This swivel section design makes adjusting the swivel-ability of the caster difficult once the caster has been assembled.
This is because the entire swivel section must be taken apart for a ”swivel restrictor” device to be inserted into the raceway. Also, once the caster swivel section raceways have worn, there is no way to adjust the swivel section to retighten.
Both kingpin and kingpinless caster swivel section designs have been around for decades and both have their advantages and disadvantages. In order to properly choose which swivel section is best for the application, it is important to know loading conditions, speed, duty cycle, jobs/hour, floor conditions, as well as any other environmental concerns.
When you are unsure what swivel section is going to serve your needs contact the engineering staff at Caster Concepts to assist with your decision making process. Caster Concepts engineers have extensive experience designing the caster that best fits your needs and applications. Proper design of the swivel section, to meet your needs, will provide you with a caster application that will last a long time.