Structure of Old-Style Office Chairs
The structure of old-style office chairs primarily includes the seat, backrest, armrests, support legs, and connecting components, with some featuring rotating or sliding functions, mainly connected through mortise-and-tenon joints or metal parts. Their design has gradually improved over historical development, with technological characteristics of different periods influencing specific structures.
Seat and Backrest: The seats of old-style office chairs are typically made of wood or upholstered. Early examples, like the Ming Dynasty official's hat chair, had seats formed by wooden planks joined together, with a flat surface and possibly rounded edges for enhanced comfort. Later, the prototype of the modern office chair invented by Thomas Warren featured an elastic cushioned seat, providing cushioning through springs or fillings. The backrests are mostly wooden frames, with some designed with curves to fit the human spine, such as the Windsor chair's backrest composed of multiple wooden slats, ensuring both support and breathability; some high-end models may have upholstered backrests filled with horsehair or cotton.
Armrests and Support Structure: Armrests are commonly found in office chairs from the mid to late periods, with earlier chairs possibly omitting this component. Armrests are mostly wooden and connected to the seat or backrest through mortise-and-tenon joints, such as the precise insertion of the armrest ends into the tenon eyes of the front legs in official's hat chairs; some swivel chairs may have armrests fixed with metal brackets to accommodate the rotating function. The support legs are usually four, arranged in an 'H' or 'X' shape, entirely wooden in the early stages and later possibly incorporating metal parts for enhanced stability. The connection between the legs and the seat relies on mortise-and-tenon structures, such as the seat of the official's hat chair being fixed to the leg frame with 'through-tenon' joints, ensuring overall sturdiness.
Functional Components and Connection Methods: The functional structures of old-style office chairs have gradually increased with technological advancements. The Windsor chair modified by Thomas Jefferson in 1775 achieved seat rotation through an iron shaft and pulleys, with its structure comprising upper and lower seat layers connected by an iron shaft, the lower seat fixed to the chair legs, and the upper seat rotating 360 degrees through pulleys; the modern office chair invented by Thomas Warren in 1849 introduced a sliding function, enabling position movement through wheels or slides at the bottom of the chair legs, while also using springs or rubber pads for seat elasticity. In terms of connection methods, mortise-and-tenon joints were predominant in the early stages, such as the 'mitered tenon' used to join the armrests and legs of Ming Dynasty chairs; later, the application of metal parts made the structure more stable, such as the iron shaft of swivel chairs being fixed to the wooden seat with screws, and the wheels being connected to the chair legs through metal brackets.
