Swivel base apparatus and method of making a swivel base
An apparatus which includes a swivel base formed of a first plate and a second plate. The first and second plates each have a central aperture which is defined by a hook-shaped section of the second plate which extends over an interior edge of the first plate defining the first plate's central aperture. The hook-shaped section is preferably circumferentially continuous and fixes the first and second plates together while allowing for sliding engagement between the first and second plates. Bearing members, such as circumferentially spaced ball bearings, are provided externally to the hook section and between the plates to facilitate sliding and load distribution. One of the plates includes hollow reception ports for holding the bearing circumferentially in place with respect to that plate while the opposite plate has a continuous riding ring in which the bearings are free to rotate. Each plate has an interior and exterior, preferably horizontal, plate section, and an intermediate section sloping between the adjacent, integral edges of the plate's interior and exterior sections. One manner of assembling the swivel base is described as well as an assembly including two structures to which the exterior sections of the plates are secured. In another embodiment, a swivel base features one or more ribs formed adjacent the elongated fastening holes. The invention also features a rounded edge extending about the entire periphery of a swivel base plate adjacent the fastener slots.