Screen supporting device and torsion adjusting structure

A screen supporting device, comprising:

• a bottom seat;
• a frame module having two opposite end portions respectively defined as a bottom end portion and a top end portion, wherein the bottom end portion is pivotally coupled to the bottom seat along a rotation axis;
• a hinge structure pivotally coupled to the top end portion of the frame module, wherein the hinge structure comprises:
• a shaft coupled through the top end portion of the frame module, wherein the shaft has a non-circular cross-section, a longitudinal direction of the shaft is defined as a central axis parallel to the rotation axis;
• and
• a washer assembly sleeved at the shaft;
• a carrying member for carrying a screen, the carrying member having a thru hole, wherein the shaft is inserted into the thru hole of the carrying member, and the carrying member is pivotable with respect to the shaft along the central axis;
• and
• a torsion adjusting structure, comprising:
• a gear formed with a circular thru hole along an axial direction thereof, wherein the shaft is inserted into the thru hole of the gear, and the gear is axially rotatable with respect to the shaft along the central axis;
• a pair of friction washers, each of the friction washers having a non-circular positioning opening conforming with the cross-section of the shaft, wherein the shaft is inserted into the positioning opening, and the friction washers respectively abut against two opposite surfaces of the gear;
• and
• a linkage assembly coupled to the carrying member and having an engaging portion, wherein a longitudinal direction of the engaging portion and the axial direction of the gear are parallel to the central axis, a predetermined distance between the engaging portion and the central axis is smaller than a radius of an addendum circle of the gear, and the engaging portion is movable between any two adjacent teeth of the gear,
• wherein when the linkage assembly horizontally moves along the central axis, the engaging portion is horizontally displaced with respect to the gear and along the central axis, the engaging portion moves along the central axis and parallel to the gear for adjusting the linkage assembly to shift to an engaging position or a separating position in relation to the carrying member;
• wherein when the engaging portion is engaged between any two adjacent teeth of the gear, the position of the linkage assembly is defined as the engaging position, and the positions of the shaft and the friction washers sleeved at the shaft hold still, the rotation of the carrying member drives the gear to axially rotate along the central axis to rub the friction washers, based on the engaging portion of the linkage assembly has engaged the gear, thereby providing the carrying member with an additional torsion;
• wherein when the engaging portion is separated from the gear, the position of the linkage assembly is defined as the separating position, the positions of the shaft and the friction washers sleeved at the shaft hold still, the relative position between the gear and the friction washers is maintained when the carrying member is rotating.