Abstract: In a chair having a base, a seat defining a fore-to-aft longitudinal axis, a seat back and a tilt control mechanism, a horizontal adjustment mechanism is provided for allowing fore-to-aft movement of the seat relative to the seat back. The mechanism includes a first plate adapted to be coupled to the seat; a second plate adapted to be coupled either directly to the base or to the tilt control mechanism, the second plate being slidably coupled to the first plate such that the two plates can move relative to one another along the longitudinal axis of the seat; an intermediate element positioned between the first and second plates for facilitating relative sliding movement therebetween, and a handle positioned between first and second plates that selectively positions the first plate in relation to the second plate.

Abstract: In a chair having a base, a seat defining a fore-to-aft longitudinal axis, a seat back and a tilt control mechanism, a horizontal adjustment mechanism is provided for allowing fore-to-aft movement of the seat relative to the seat back. The mechanism includes a first plate adapted to be coupled to the seat; a second plate adapted to be coupled either directly to the base or to the tilt control mechanism, the second plate being slidably coupled to the first plate such that the two plates can move relative to one another along the longitudinal axis of the seat; an intermediate element positioned between the first and second plates for facilitating relative sliding movement therebetween, and a handle positioned between first and second plates that selectively positions the first plate in relation to the second plate.

Abstract: This invention provides a spring assembly for use in a chair tilt control mechanism. The tilt control mechanism is one that can recline and return a backrest for a chair. The spring assembly includes a cylindrical block that has first and second ends and a central bore. A pair of end caps is located at each of the first and second ends of the block. Each end cap has a receiving section that can rotate within the central bore of the block. Each end cap also has a hole extending through it that provides a coupling point for the chair backrest. The spring assembly also includes at least one steel coil spring around the block. The spring has one terminal end coupled to the tilt control mechanism and the other end coupled to one of the end caps. The end caps rotate within the block as the chair backrest is reclined or returned. The force needed to rotate the end caps is a sum of the spring force provided by the spring and the frictional relationship between the block and the end caps.

Abstract: This invention provides a spring assembly for use in a chair tilt control mechanism. The tilt control mechanism is one that can recline and return a backrest for a chair. The spring assembly includes a cylindrical block that has first and second ends and a central bore. A pair of end caps located at each of the first and second ends of the block. Each end cap has a receiving section that can rotate within the central bore of the block. Each end cap also has a hole extending through it that provides a coupling point for the chair backrest. The spring assembly also includes at least one steel coil spring around the block. The spring has one terminal end coupled to the tilt control mechanism and the other end coupled to one of the end caps. The end caps rotate within the block as the chair backrest is reclined or returned. The forced needed to rotate the end caps is a sum of the spring force provided by the spring and the frictional relationship between the block and the end caps.