Abstract: A keyboard support mechanism containing a novel articulating arm mechanism for permitting vertical movement of the keyboard shelf. The articulating arm mechanism has six major components: (1) a mounting bracket, (2) a mounting bracket support in combination with a swivel bracket, (3) a shelf bracket, (4) an upper aim, (5) at least one side arm, and (6) at least one stopping member. The upper arm links the shelf bracket and the mounting bracket; the side arm and the stopping means cooperate to keep the shelf bracket (and hence the keyboard shelf) at a constant angle relative to the ground.

Abstract: A chair of the tilting type which includes a base, a seat and back, with the base pivotally supporting the seat with two parallel links of a four-bar parallel linkage, with one of the links extending to support the back. The four-bar linkage is duplicated on each side of the chair by forming the two opposite parallel links or cranks from the upturned ends of the tubes which pass through the base in parallel but vertically offset fashion, the base thus forming the fixed bar of the linkage with its opposite bar or coupler being formed by the seat. A spring within the base is operative on one (of both) of the tubes to urge the chair to an upright position. The tubes are pivotally connected to the seat and one of the tubes extends and is fixedly connected to the back. As the back tilts, the four-bar mechanism is engaged and lifts the seat which thereby uses the occupant's weight to counteract the reclining.