A link locking device of a vehicle seat is configured to prevent a force exerted on a seat belt from causing the rotation of a height link through a buckle. The device includes a sector gear unit rotatably fastened to a cushion frame and fastened to a link connection unit, to which a height link provided in a seat rail is rotatably coupled, to rotate together and a locking unit rotatably coupled to the cushion frame and fastened to a buckle of a seat belt to engage the sector gear unit and block the rotation of the link connection unit when the buckle is pulled. In this configuration, when the buckle is pulled, the locking unit engages the sector gear unit to restrain the link connection unit from rotating to prevent the rotation of the height link, thereby having the effect of preventing the distortion of the seat cushion.

Shock absorbing seatbelt height adjusters for use with vehicle occupant restraint systems, and associated systems and methods are disclosed herein. In one embodiment, a shock absorbing height adjuster includes a D-loop assembly slidably coupled to a rail, and a stop assembly and a pre-loader slidably coupled to the rail on opposite sides of the D-loop assembly. The stop assembly and the pre-loader can be releasably lockable at a plurality of positions along the rail. A biasing member can be compressed between the pre-loader and the D-loop assembly to urge the D-loop assembly toward the stop assembly and allow motion of the D-loop assembly toward the pre-loader under load. The position of the pre-loader can be adjusted to vary the compression in the biasing member.

A height adjuster of a seat belt for a vehicle may include a rail bracket configured to be fixedly mounted on a vehicle body so that rail grooves are formed to be continuously connected and the rail grooves are vertically disposed on the rail bracket, a slider configured to be coupled to the rail bracket and moving along a length direction of the rail bracket and having left and right surfaces provided with guide grooves so as to be fitted in edge portions of the rail bracket which are provided with the rail grooves, and a locking mechanism configured to be coupled to the slider so as to elastically slidably move and restrict a movement of the slider at a time of contacting the rail groove and release the restriction of the movement of the slider at a time of being separated from the rail groove.