US Patent 10143310 Rotary positioning device for armrest assembly

A rotary positioning device for an armrest includes a positioning member, a base, a sliding member, and a detent member. The positioning member includes a plurality of first engaging recesses formed at a side edge thereof. The base is rotatably connected to the positioning member. The sliding member is slidably arranged in base and is selectively switchable between a locked position and an unlocked position. The detent member is movably arranged in the base and is selectively engaged with one of the plurality of first engaging recesses to correspond to the locked position or the unlocked position of the sliding member.