| 摘要 |
PURPOSE: To lower a return torque at a backward inclining time rather than a linear increase by shifting a rotational axial line of an elastic spring against a rotational axial line of a seat driving tube and increasing a moment arm of the spring at an inclining time of a chair seat. CONSTITUTION: When a chair is used, a seat moving tube 71 and a piece 79 of a square steel tube are rotated in a counterclockwise direction as shown in the drawing by means of a weight of an user, and an arm 59 of an elastic spring 41 is rotated in a clockwise direction as shown in the drawing. Furthermore, a cam surface 61 of a block 63 of the arm 59 is extended in a non-radial direction as to a rod 43 and the elastic spring 41 is rotated around the rod 43. Thereby, when rotational angles of the driving tube 71 and the spring 41 increase, an effective moment arm length 59 of the spring increases. Thereby, a return force applied by the spring 41 against the moving tube 71 decreases. Thus, a return torque resistance of a chair controller for returning a seat to a forward position is not linear within a total inclining range of a char seat. |
