Backrest height adjustment mechanism

Abstract

This invention relates to a backrest height adjustment mechanism, which mainly consists of an adjustment structure between the backrest assembly and the chair backrest tube to adjust the height of the backrest assembly. The chair backrest tube has a backrest mounting base for mounting the backrest assembly, and the backrest assembly has an adjustment seat that passes through the backrest mounting base. The adjustment seat has several adjustment slots, and a pull rod that passes through the backrest mounting base is positioned in each of the adjustment slots or can be disengaged from the adjustment slots to move the adjustment seat, allowing the user to adjust the backrest assembly according to their own comfortable height. In addition to adjusting the backrest support height, this mechanism also allows the backrest to be lowered to reduce packaging volume, increase the number of containers that can be loaded, and facilitate transportation.

Claims

1. A backrest height adjustment mechanism, mainly provided between a backrest assembly and a chair backrest tube, the backrest height adjustment mechanism comprising: an adjustment seat, the top of which is correspondingly mounted and connected to the backrest assembly, having an elongated channel extending upward from the bottom end, and having a plurality of adjustment slots at the front end of the adjustment seat facing the elongated channel; a backrest fixing seat, correspondingly covering and connected to the chair backrest tube, having a front slot hole at the front end of the backrest fixing seat facing the plurality of adjustment slots, and a through slot hole for the adjustment seat to be inserted downward from the end face, the through slot hole communicating with the front slot hole, and having a rear slot hole at the rear end of the backrest fixing seat facing the front slot hole; a pull rod, fitted with an elastic element, and inserted through the rear slot hole, passing through the chair backrest tube, the elongated channel to the front slot hole, and having a locking block at the end of the pull rod, the locking block being located in the front slot hole, and the elastic element being located in the rear slot hole; The locking block can be positioned by locking into one of the adjustment slots as the pull rod moves, or it can be released from one of the adjustment slots to release the adjustment seat, allowing the adjustment seat to move the backrest assembly to adjust the height.

2. The backrest height adjustment mechanism as described in claim 1, wherein the backrest fixing seat is further composed of a front seat and a rear seat, wherein a first recess is formed in the front seat at the location corresponding to the chair back tube, and a second recess is formed in the rear seat at the location corresponding to the chair back tube, the first and second recesses correspondingly covering the chair back tube, and are locked by fasteners passing through the rear seat, the chair back tube and the front seat.

3. The backrest height adjustment mechanism as described in claim 2, wherein the through slot is provided on the front seat and communicates with the front slot, such that the front slot is located on the front end face of the front seat, the rear slot is located on the rear seat, and a through hole is provided on the chair back tube for the pull rod to pass through.

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