.~.~ Pivot axis located at or adjacent to a central point of back
DEFINITION
Classification: 297/354.11
Pivot axis located at or adjacent to a central point of back:
(under subclass 354.1) Device wherein the pivot axis is coincident with or adjacent to a substantially horizontal axis passing through a point located at or near a midpoint of the back.
SEE OR SEARCH THIS CLASS, SUBCLASS:
291, for a centrally-pivoted backrest with a spring.