Patent ID: 7735924

Claim:
A positioning device for a chair comprising, in combination: a clamping seat including first and second clamping members pivotably connected together, with each of the first and second clamping members including a clamping portion on a first end thereof, with the clamping portions of the first and second clamping members being adapted to be mounted around a fixed rod of a chair, with the first clamping member further including a first through-hole, with the second clamping member further including a second through-hole, with a spring mounted between the first and second clamping members to bias the clamping portions to an open state not clamped on the fixed rod, allowing movement of the clamping seat along the fixed rod, with the first clamping member further including a coupling portion adapted to be fixed to a side of an inclinable seat of the chair that is moveable relative to the fixed rod; a positioning block mounted to the second clamping member and including first and second sides and a third through-hole extending from the first side through the second side of the positioning block and aligned with the second through-hole of the second clamping member, with the second side of the positioning block including a protrusion; an adjusting rod including a coupling seat and a handle fixed to the coupling seat to move therewith, with the coupling seat including first and second sides and a fourth through-hole extending from the first side through the second side of the coupling seat, with the first side of the coupling seat including a positioning groove having a low-profile section, a high-profile section, and a transition section between the low-profile section and the high-profile section, with the handle pivotable between a release position and a clamping position; a first coupling rod extending through the first, second, third, and fourth through-holes, with the protrusion of the positioning block received in the positioning groove of the coupling seat and engaged with one of the low-profile section and the high-profile section, wherein when the handle is in the release position, the protrusion of the positioning block is engaged with the low-profile section, and the first and second clamping members are in an open state under the action of the spring, so that the clamping portions of the first and second clamping members are not clamped on the fixed rod, allowing movement of the clamping seat along the fixed rod and allowing movement of the inclinable seat relative to the fixed rod, and wherein when the handle is in the clamping position, the protrusion of the positioning block is engaged with the high-profile section, and the first and second clamping members are in a clamping state, so that the clamping portions of the first and second clamping members are clamped on the fixed rod, not allowing movement of the clamping seat along the fixed rod and not allowing movement of the inclinable seat relative to the fixed rod.