초록 ▼

A tilt control mechanism for an office chair includes a spring arrangement which permits forward and rearward tilting of the chair while also urging the chair to a normal upright position. The spring arrangement includes front and rear springs which act in combination such that the upward acting for

A tilt control mechanism for an office chair includes a spring arrangement which permits forward and rearward tilting of the chair while also urging the chair to a normal upright position. The spring arrangement includes front and rear springs which act in combination such that the upward acting forces acting on the chair can be varied during use. The forces being applied by the front spring are adjusted by a side-actuated tension adjustment mechanism which incorporates a wedge block for adjusting the spring forces. Further, the rear springs provide a variable spring force such that the spring force is maximized when in the normal position but is decreased substantially once the chair is fully reclined. This reduction in spring force allows a user to maintain the chair in the fully reclined position with significantly less force than was required to tilt the chair rearwardly while a sufficient spring force continues to be applied by the front spring to urge the chair to the normal position.

대표청구항 ▼

[ What is claimed is:] [1.]1. In a chair having a base, a seat assembly and a tilt control mechanism which is supported on said base and connects said seat assembly to said base, said tilt control mechanism permitting rearward tilting of said seat assembly relative to said base, said tilt control me

[ What is claimed is:] [1.]1. In a chair having a base, a seat assembly and a tilt control mechanism which is supported on said base and connects said seat assembly to said base, said tilt control mechanism permitting rearward tilting of said seat assembly relative to said base, said tilt control mechanism including a fixed housing supported on said base and a pivot member which supports said seat assembly, said pivot member being pivotable vertically relative to said fixed housing about a sidewardly extending generally horizontal pivot axis in response to tilting of said seat assembly, comprising the improvement wherein said tilt control mechanism includes a tilt lock mechanism for preventing tilting of said seat assembly relative to said base, said tilt lock mechanism including a lock assembly for preventing said tilting and an over-center actuator assembly for actuating said lock assembly to lock and unlock said lock assembly, said actuator assembly including a support bracket and a generally V-shaped ramp which are disposed in spaced apart relation, said actuator assembly further including an actuator rod which is rotatably supported by said support bracket and includes a transverse leg at an inner end thereof which is slidable along said ramp, and a resilient member for biasing said leg to one side or the other of an apex of said V-shaped ramp, said resilient member having one end connected to said support bracket and an opposite end acting axially on said rod for biasing said rod axially, said resilient member biasing said transverse leg axially away from said apex to first or second positions on opposite sides of said apex while permitting axial displacement of said rod to permit sliding of said leg over said apex during rotation of said actuator rod.