1. Field of the Invention
The invention relates to a height adjusting device for a chair, in which most of the components of the device are concealed behind a backrest member of the chair.
2. Description of the Related Art
A conventional height adjusting device is mounted between a seat member and a backrest member of a chair, and includes a mounting frame which is secured on the seat member and which has an upright passage. A sliding member includes an upper end portion which is secured on the backrest member, and a lower end portion which is mounted in and which is movable relative to the upright passage and which is formed with a plurality of retained holes. The mounting frame has a pair of lug portions which are spaced apart from each other transverse to the upright passage such that a coil spring and a retaining member are mounted therebetween via a mounting shaft. The retaining member has a fulcrum portion which is mounted on the mounting shaft, and an engaging end and an actuated end which are disposed at two opposite sides of the fulcrum portion. The coil spring has two ends which abut against the mounting frame and the engaging end to urge the engaging end to engage one of the retained holes via a through hole in the mounting frame. When the height of the backrest member is to be adjusted relative to the seat member, the actuated end is depressed to turn the engaging end so as to disengage the engaging end from the retained hole and to permit sliding movement of the sliding member relative to the mounting frame.
It is noted that most of the components of the conventional height adjusting device are not concealed behind the backrest member, thereby resulting in an untidy appearance.
Therefore, the main object of the present invention is to provide a height adjusting device for a chair, in which most of the components of the device are concealed behind a backrest member of the chair to result in a tidy appearance.
Accordingly, a height adjusting device of the present invention is adapted to be mounted between a seat member and a backrest member of a chair, the backrest member extending in an upright direction. The height adjusting device includes a mounting frame, a sliding member, a lever member, and a biasing member. The mounting frame includes a proximate end portion adapted to be secured to the seat member, a distal end portion opposite to the proximate end portion in the upright direction and adapted to be disposed rearwardly of the backrest member, and an intermediate portion interposed between the proximate and distal end portions. The intermediate portion has front and rear intermediate wall surfaces opposite to each other in a first direction transverse to the upright direction. The rear intermediate wall surface includes a plurality of retaining members spacedly displaced from one another in the upright direction. The sliding member is adapted to be secured to the backrest member, and includes first front and rear major wall surfaces opposite to each other in the first transverse direction and mounted to be slidable relative to the intermediate portion of the mounting frame in the upright direction. The first front major wall surface is adapted to be spaced apart from the backrest member, and is disposed rearwardly of the rear intermediate wall surface. The first rear major wall surface includes an upper portion which defines a passageway extending in the first transverse direction to be communicated with the first front major wall surface, and a lower portion extending from the upper portion in the upright direction. The lever member is pivotally mounted on the lower portion at a fulcrum and about a pivotal axis which is transverse to both of the upright direction and the first transverse direction. The lever member includes actuating and retained ends respectively at two opposite sides of the fulcrum, and is disposed such that the retained end is extendable through the passageway to be disposed forwardly of the first front major wall surface so as to be retained by one of the retaining members, when the actuating end is manually operated to turn the retained end about the pivotal axis. The biasing member is disposed to bias the retained end to extend through the passageway so as to be retained by said one of the retaining members.