| 主权项 |
1. An omnidirectional adjustment-oriented positioning device of an office chair armrest, comprising: an armrest component axially disposed at an upper end of an armrest fixing unit fixed at a pad laterally and at an upper end of a swing link component of a parallel four-bar linkage device so as to be rotatable, wherein
the swing link component comprises a rotation base pivotally disposed on the armrest fixing unit and having an upper end provided with a pivot portion and an armrest rotation fixing unit pivotally fixed to an armrest component and having a lower end provided with a pivot portion, wherein an inner link is pivotally connected between and slightly outside the two pivot portions of the armrest rotation fixing unit and the rotation base, wherein two sides of a middle of each of the two pivot portions are pivotally fixed in place to enclose an inner link and two parallel opposing outer links; a bump portion and a rotation-proof recess being substantially polygonal and annular and having a bottom which an oblong hole is disposed on are centrally disposed on a lateral surface of the pivot portion of the armrest rotation fixing unit, wherein an inner wheel component and an external wheel component each have two opposing surfaces which annular continuous bevel gears meshing each other are disposed on and each have a lateral surface which an engaging slot corresponding in position to the oblong hole is disposed on are disposed in the rotation-proof recess, such that the inner wheel component is centrally fitted around the bump portion and thus rotatable, wherein the external wheel component corresponds in shape to the rotation-proof recess and is received therein to thereby be able to move axially only, wherein a positioning wheel abuts against an outer side of the external wheel component and is centrally provided with a polygonal rotation-proof hole, such that the rotation-proof hole gets fitted around a polygonal rotation-proof bump convexly formed and corresponding in position to the outer link, wherein a spring serving to push is disposed between the outer link and the positioning wheel, wherein an annular gear portion is disposed at the pivot portion of the armrest rotation fixing unit and the positioning wheel to effectuate the resilient abutting and meshing thereof, wherein the inner side of the positioning wheel abuts against the external wheel component resiliently, wherein a rotation component is disposed in the armrest rotation fixing unit, wherein the rotation component has its substantially central part pivotally fixed in place to thereby extend outward, wherein a post portion is convexly formed on each of the two sides at the inner end of the rotation component, wherein the post portion penetrates an oblong hole disposed on a lateral side of the armrest rotation fixing unit and thus gets engaged with the engaging slot disposed on the inner side of the inner wheel component, wherein the rotation component is rotated to drive the inner wheel component to rotate, such that the bevel gears drive the external wheel component to move outward and thus cause the positioning wheel to withdraw together with the external wheel component, wherein the positioning wheel and the pivot portion of the armrest rotation fixing unit operate to separate positioning gears otherwise meshing with each other, such that the swing link component can rotate and adjust the forward, backward and vertical positions of the armrest component. |
