5009 results about "Leaf spring" patented technology

A task chair, including a backrest assembly and a seat assembly pivotally coupled both to one another and to side portions of a fixed yoke member for synchronized movement, in which the seat of the seat assembly moves upwardly and forwardly concurrently with recline of the backrest of the backrest assembly. The chair further includes a tension assembly including an elongate tension member, such as a leaf spring, secured at one end thereof to the yoke member, and a contact member, such as a contact roller, adjustably mounted to the seat assembly. The contact member engages the tension member such that the tension member resists recline of the backrest assembly and concurrent movement of the seat assembly from their initial positions, and also provides a restoring force which tends to move the backrest to its initial upright position and the seat to its initial rearward and lowered position. The contact member is adjustable with respect to the tension member in order to vary the effective moment arm acting upon the tension member, thereby varying the pre-load of the tension member and the resistance provided by the tension member.

A synchrotilt chair includes a base, a back, a seat, and a pair of parallel links pivoted to a rear of the base and to a bottom of the back to form a four-bar linkage arrangement. A spring arrangement includes leaf springs that extend between each link and the base to bias the link and in turn the back and seat toward an upright position, with the back and seat pivoting with a synchronous motion upon recline of the back. The base, the back, the seat, and the links are shaped to receive identical chairs along a stacking direction to form a densely nested stacked arrangement for compact storage. The base has a distinctive horizontal U-shaped mid-frame structure defining a plurality of corners, and further having up legs and down legs extending upwardly and downwardly, respectively, from each of the corners, with the pair of links attached to the two rearmost ones of the up legs. The base (and also separately the back and the seat structures) are injection molded as single pieces from a reinforced polymeric material in a manner that provides a lightweight, yet surprisingly rigid and sturdy construction. Armrests are pivoted to the back and have a shape configured to allow nested stacking while also providing excellent comfort, durability, and style.