Abstract: A reclining seatback support device which mainly includes at least one seatback support and a seatback body is revealed. The seatback body and an upper end of the seatback support are provided with pivot bracket portions pivotally connected to each other while a lower part of the seatback body and the seatback support are connected by a swing arm. When a user is sitting and lying down on the back, the seatback body is rotated around the pivot axis where the seatback body is pivotally connected to the upper end of the seatback support and then reclined at a certain angle. By elastic segments of the seatback body and the swing arm between the lower part of the seatback body and the seatback support for pulling and limiting the seatback body, the user can lean on the seatback body comfortably and safely.

Abstract: The present invention discloses a structure for rapidly assembling a chair back and a chair seat. It comprises a chair seat underframe having a first engaging portion and an assembling channel and a chair back stand having a second engaging portion and an assembling block for correspondingly engaging with the assembling channel. The assembling channel has two protrusions at two lateral walls and the assembling block has two engaging grooves at two laterals for positioning and engaging with the two protrusions. The assembling channel of the chair seat underframe has an engaging hole, and a telescopic pin disposed at a bottom of the assembling block is positioned and engaged with the engaging hole. The assembling channel of the chair seat underframe and the assembling block of the chair back stand are further screwed together by a screwing member.

Abstract: A twistable chair backrest frame is disclosed herein. It has a hollow section and two opposite elastic supporting ribs at a right side and a left side of the hollow section.

Abstract: The adjusting mechanism serves for the setting of a restoring force acting on the backrest of a chair. A back support and a seat support are fastened on a support. A setting mechanism configured in the manner of scissors is provided for the weight setting. Said setting mechanism has two scissor arms which are connected to one another via a scissor pin. One of said scissor arms is formed by a spring element and is fastened with its front-side spring end on said support. The back spring end is fastened on said scissor pin. Said first scissor arm is connected to said back support in the manner of a connecting rod. An active lever length is defined between said scissor pin and a support pin about which said back support is mounted pivotably. A compact construction mode is achieved by the configuration of said scissor arm as a spring element.

Abstract: The adjusting mechanism serves for the setting of a restoring force acting on the backrest of a chair. A back support and a seat support are fastened on a support. A setting mechanism configured in the manner of scissors is provided for the weight setting. Said setting mechanism has two scissor arms which are connected to one another via a scissor pin. One of said scissor arms is formed by a spring element and is fastened with its front-side spring end on said support. The back spring end is fastened on said scissor pin. Said first scissor arm is connected to said back support in the manner of a connecting rod. An active lever length is defined between said scissor pin and a support pin about which said back support is mounted pivotably. A compact construction mode is achieved by the configuration of said scissor arm as a spring element.