Apparatus and methods for the understructure of a chair base
AssigneeMedway Plastics Corporation
InventorsThomas A. Hutchinson, Jr., Gerald A. Hutchinson, Richard E. Hutchinson
Life of this patent
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Abstract
The embodiments relate to a geometric under structure, central and outer hub for a GFN plastic chair base. The geometric shape and dimensions are critical components to the overall strength of the chair base hub and arms when either vertical or rotational forces are applied at the central hub. The central hub is of sufficient thickness to maintain dimensional stability when the forces are applied. The overall geometry and material composition enable the hub area to be constructed with minimal plastic wall thickness while optimizing the physical strength of the article and facilitating high production rate.
Claims19
A molded chair base comprising a bottom and a top, the chair base further comprising:
- a central structure;
- a plurality of arms extending from the central structure, each arm comprising:
- a shell comprising a first and second wall of the arm;
- at least one arm rib extending from the first wall to the second wall of the arm, the at least one arm rib having a variable thickness, such that the thickness near the top of the chair base is greater than the thickness near the bottom of the chair base;
- at least one arm core comprising a void having walls tapering upwardly from their base such that a first cross-sectional area of the void near a bottom of the chair base is larger than a second cross-sectional area of the void near the top of the chair base, the first cross-sectional area and the second cross-sectional area being vertically aligned with each other and the tapering occurring consistently along a height of the void.
A molded chair base comprising a bottom and a top, the chair base further comprising:
- a hub;
- a hoop structure encircling the hub, a plurality of arms extending from the hoop structure;
- the hoop structure comprising:
- a plurality of hoop ribs extending radially from the hoop structure, each hoop rip having a variable thickness, such that the thickness near the top of the chair base is greater than the thickness near the bottom of the chair base;
- at least one hoop core comprising a void between the hoop ribs, the void having inwardly tapered walls such that a first cross-sectional area of the void near the bottom is wider and a second cross-sectional area of the void near the top is narrower.
Dependencies are inferred from the claim text.