Office Chair Shaft
The "shaft" of an office chair has different meanings and applications in different scenarios, mainly including the "three-axis" design in structural innovation, the shaft in the middle of the universal wheel, and the rotating shafts (bottom shaft and hip shaft) of ergonomic chairs.
The "three-axis" design in structural innovation: Designer Li Chuanjun proposed that office chair structures would enter the "three-axis" era. This design concept is based on in-depth research into the movement patterns of the human spine. By identifying the three axes of spinal movement, namely the movement axes of the cervical, thoracic, and lumbar curves, the chair is designed accordingly. This design enables the chair to better conform to the "S"-shaped curve of the human spine, achieving a "chair-human unity" effect. As the human sitting posture changes, the chair can adjust along with the movement of the spine, effectively improving the impact of seating furniture on human health and reducing spine-related diseases caused by improper sitting postures.
The shaft in the middle of the universal wheel: The wheels of an office chair usually adopt a snap-fit structure, with the metal shaft fixed inside the wheel frame through friction or a slot. When it is necessary to disassemble the wheels, different methods are used depending on the situation. If the metal shaft is slightly rusted, the tapping method can be employed. Use a claw hammer or rubber mallet to gently tap the end of the shaft core from the outside of the wheel towards the inside. For plastic snap-fit wheels, the plier extraction method can be used. Use needle-nose pliers to grip the protrusion at the bottom of the shaft core, rotate it counterclockwise, and pull it out. If there is significant resistance, lubricant can be sprayed. For wheels that have not been maintained for a long time, first clear away debris, then apply cooking oil or liquid paraffin and let it sit for half an hour before rotating and pulling it out.
The rotating shafts (bottom shaft and hip shaft) of ergonomic chairs: Most ergonomic chairs on the market adopt a bottom-shaft structure, with the rotating shaft hidden beneath the seat cushion and misaligned with the pivot point of the human hip joint. When changing postures, the lumbar support tends to detach from the lumbar spine, causing the user to feel increasingly tired the longer they sit. In contrast, a hip-shaft structure, such as the FLOW hip-shaft synchronous lumbar support system of the Yongyi Flow550, connects the left and right armrests with a single axis that passes through the position of the human hip joint when seated, making the human hip joint and the chair's rotational axis share the same center. When leaning back, the backrest and waist move together, better conforming to the waist and reducing fatigue from prolonged sitting.
