1. Sitting height-feet not hanging in the air: Sitting height refers to the vertical distance from the seat surface to the ground. An ergonomic chair requires a proper sitting height so that the thighs should be level, the calves should be vertical, and the feet should be flat on the ground. Sitting height = calf socket height + heel thickness-proper clearance. The sitting height of the mahogany chair is basically about 500mm, and has feet. Generally, the distance from the ground is about 90mm. The difference between the two is about 410, which is basically the same as the national standard (national standard: sitting height is 400mm-440mm, size The level difference is 10mm), this sitting height effectively ensures comfort.
2. Sitting depth-not exceeding thigh length: Sitting depth refers to the distance from the front edge to the back edge of the chair surface. Sitting depth has a great influence on the comfort of the human sitting posture. If the chair sits deeper than the horizontal length of the thigh, the human body will have a great inclination against the backrest, and the waist lacks support points and hangs, which intensifies the strength of the waist muscle activity and causes fatigue; at the same time, the sitting surface is too deep, causing the knee socket It produces a numb reaction and is not conducive to standing up. The sitting depth of the chair is about 410mm, which is completely consistent with the average horizontal thigh length of the human sitting posture in my country, which is 445mm for men and 425mm for women, minus the distance between the front of the seat and the inside of the knee (about 60mm).
3. The backrest plate-S fits the shape of the human spine: the side of the human spine is in an “S” shape in the natural state. And according to the necessary backward inclination of the human body when resting, the result of this treatment is that when a person sits on a chair, the back has a larger contact surface with the chair backboard, and the ligaments and muscles are fully rested.
Fourth, the armrests—the shape is reasonable and the height is suitable. The height of the armrest is generally about 220mm. The shape of the armrest of the armchair can fully support the arm. This is the same as the vertical distance between the upper surface of the armrest and the seat surface required by modern engineering to be 200mm-250mm.