CASTER COMPONENTS

Caster are made from several components as follows:

1. YOKE:  The portion that supports both the upper and lower raceways.  It also consists of the legs which the wheel is mounted between.   Case hardened.   The yoke can be manufactured as a single formed piece of steel which is completely case hardened, or as a case hardened swivel head with legs welded to it.  A rigid yoke would consist of just a top plate with legs welded to it, or a one piece formed yoke with the top plate a part of the formed yoke. The yoke is also referred to as the "rig".

2. SWIVEL RACEWAY:  The part of the swivel that contains the balls and bearings.  Both upper and lower raceways are contained by the yoke on one side and a hard cap on the upper raceway, with a retainer on the lower raceway.  All parts of the raceway are case hardened.  There are two types of bearings in the swivel raceway: 

3. ANTI-FRICTION BEARINGS:  Bearings of this type consist of balls or rollers of uniform size operating directly in raceways formed or machined into the caster horn and top plate.  PRECISION UNIT BEARING ASSEMBLIES:  Are made to close tolerances in accordance with high grade bearing manufacturers' practice and are replaceable as complete assemblies.

4. HARD CAP:  Contains the lower portion of the bottom raceway.  Case hardened.

5. DUSTCAP:  Fits over hardcap to protect the raceway from foreign materials.

6. MOUNTING PLATE/STEM:  Used to attach the caster to the piece of equipment it is being installed on.  Also known as the adapter.

7. KING BOLT/RIVET:  Used to hold the swivel components together.  King bolt is threaded with a nut tightened over the lower end to hold swivel together.  The rivet is either staked with a punch press, or orbitally riveted.  When using a stem, the king bolt or rivet are manufactured as part of the stem.

8. AXLE & NUT:  Used to hold wheel in legs of assembly.

9. WHEEL:  Manufactured from a variety of materials.  The part of the caster that rolls on the floor surface.

10. WHEEL BEARINGS:  Bearings in the core of the wheel that, depending on the type, will allow the wheel to roll with varying degree of ease.  Do not affect load capacity of the wheel.

11. THREAD GUARDS:  Also known as string guards or dust covers.  Fits over sides of wheels.  Designed to keep thread and other foreign material out of the axle and bearings.