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US 5,511,852 AGranted
Adjustable backrest for a chair
AssigneeHerman Miller, Inc.
InventorsJames L. Kusiak, Rodney C. Schoenfelder
Life of this patent
Estimating the term…
Abstract
An apparatus is provided for adjusting the position of a backrest relative to a chair seat. The backrest includes an elongated stem having a curved lower portion. Preferably, a spring operably engages the stem to bias it in an upward direction. A housing is adapted to slidably receive the curved portion of the stem and guide the spring. A latch mechanism is adapted to engage the stem to lock the backrest in a desired position, and an actuator member is adapted to move the latch mechanism between an engaged and disengaged position. In operation, the latch mechanism is disengaged to allow the backrest stem to move in a curvilinear path to a desired height and corresponding angular position, and reengaged to lock the backrest stem in said position.
Claims23
An apparatus for adjusting the position of a backrest relative to a chair seat, comprising:
- said backrest including an elongated stem having a curved lower portion and a lower terminal end;
- a spring operably engaging the stem at a point sufficiently distant from said terminal end such that the entirety of the spring is constrained by the stem when the backrest is in a lowered position, wherein said spring operates to bias said stem in an upward direction;
- a stationary housing adapted to slidably receive the curved portion of the stem and guide the spring;
- a latch mechanism adapted to lock the lower portion of the stem in a plurality of desired fixed positions within the housing such that the back of a user can rest against the backrest in said positions;
- an actuator member adapted to move the latch mechanism between an engaged and disengaged position;
- and
- whereby disengagement of the latch mechanism allows the backrest stem to move in a curvilinear path to a desired height and corresponding angular position for the backrest, and whereupon reengagement of the latch mechanism locks the backrest stem in said position.
4 more elements
An apparatus for adjusting the position of a backrest relative to a chair seat, comprising:
- said backrest including an elongated stem having a curved lower portion and a lower terminal end;
- a spring operably engaging the stem distally of said terminal end to bias said stem in an upward direction;
- a stationary housing adapted to slidably receive the curved portion of the stem and guide the spring;
- a latch mechanism adapted to lock the lower portion of the stem in a plurality of desired fixed positions within the housing such that the back of a user can rest against the backrest in said positions, wherein the latch mechanism comprises a rack on the lower portion of the stem and a pawl adapted to operably engage the rack at selected locations including a proximal location and a distal location, a terminal portion of the spring engaging the stem at approximately said distal location;
- an actuator member adapted to move the latch mechanism between an engaged and disengaged position;
- and
- whereby disengagement of the latch mechanism allows the backrest stem to move in a curvilinear path to a desired height and corresponding angular position for the backrest, and whereupon reengagement of the latch mechanism locks the backrest stem in said position.
4 more elements
An apparatus for adjusting the position of a backrest relative to a chain seat, comprising:
- said backrest including an elongated stem having a curved lower portion and a lower terminal end, wherein the lower portion of the stem curves along an arc having a center defined by a horizontal line approximately through the hip joints of a user sitting in the chair seat;
- a spring operably engaging the stem distally of said terminal end to bias said stem in an upward direction;
- a stationary housing adapted to slidably receive the curved portion of the stem and guide the spring;
- a latch mechanism adapted to lock the lower portion of the stem in a plurality of desired fixed positions within the housing such that the back of a user can rest against the backrest in said positions;
- an actuator member adapted to move the latch mechanism between an engaged and disengaged position;
- and
- whereby disengagement of the latch mechanism allows the backrest stem to move in a curvilinear path to a desired height and corresponding angular position for the backrest, and whereupon reengagement of the latch mechanism locks the backrest stem in said position.
4 more elements
An apparatus for adjusting the position of a backrest relative to a chair seat, comprising:
- said backrest including an elongated stem having a curved lower portion and a lower terminal end;
- a spring operably engaging the stem distally of said terminal end to bias said stem in an upward direction;
- a stationary housing adapted to slidably receive the curved portion of the stem and guide the spring;
- a latch mechanism adapted to lock the lower portion of the stem in a plurality of desired fixed positions within the housing such that the back of a user can rest against the backrest in said positions, wherein the latch mechanism is enclosed by the housing and comprises a rack on the lower portion of the stem and a pawl rotatably attached to the housing by a rod;
- an actuator member adapted to move the latch mechanism between an engaged and disengaged position, wherein the actuator member comprises a lever external to a side of the housing for rotating the pawl between engaged and disengaged positions with the rack;
- and
- whereby disengagement of the latch mechanism allows the backrest stem to move in a curvilinear path to a desired height and corresponding angular position for the backrest, and whereupon reengagement of the latch mechanism locks the backrest stem in said position.
4 more elements
An apparatus for adjusting the position of a backrest relative to a chair seat, comprising:
- said backrest including an elongated stem having a curved lower portion and a lower terminal end;
- a spring operably engaging the stem distally of said terminal end to bias said stem in an upward direction;
- a housing adapted to slidably receive the curved portion of the stem and guide the spring, wherein the housing is adjustably attached to a rear portion of a seat support member, said housing being movable between a forward position adjacent the seat support member and a rearward position spaced apart from said seat support member, thus allowing fore and aft adjustment of the backrest;
- a latch mechanism adapted to lock the lower portion of the stem in a plurality of desired fixed positions within the housing such that the back of a user can rest against the backrest in said positions;
- an actuator member adapted to move the latch mechanism between an engaged and disengaged position;
- and
- whereby disengagement of the latch mechanism allows the backrest stem to move in a curvilinear path to a desired height and corresponding angular position for the backrest, and whereupon reengagement of the latch mechanism locks the backrest stem in said position.
4 more elements
A backrest adjustment apparatus for use with a chair having a base structure and a seat mounted on a seat support member, the apparatus comprising:
- a backrest including an elongated stem having a curved lower portion;
- a housing mounted to the seat support member and having an aperture for slidably receiving the curved portion of the stem and a cavity therein for accommodating said curved portion, the cavity having a greater width than the aperture;
- a latch mechanism positioned within the housing cavity and adapted to engage the stem to lock the backrest in a plurality of desired positions such that the back of a user can rest against the backrest in said positions, the latch mechanism comprising a rack on the lower portion of the stem and a pawl adapted to operably engage the rack at selected locations, the rack having a width greater than the curved lower portion of the stem such that the rack slidably fits within the cavity and the stem slidably fits within the aperture, said width of the rack being greater than the width of the aperture in the housing to provide an uppermost stop for adjusting the backrest;
- and
- an actuator member accessible from outside the housing for moving the latch mechanism between an engaged and disengaged position;
- whereby disengagement of the latch mechanism allows the backrest stem to move in a curvilinear path to a desired height and corresponding angular position for the backrest, and whereupon reengagement of the latch mechanism locks the backrest stem in said position.
3 more elements
A chair comprising:
- a base structure;
- a seat support member tiltably mounted to the base structure;
- a backrest including an elongated stem having a curved lower portion;
- and
- a housing adjustably attached to a rear portion of the seat support member and adapted to slidably receive the curved portion of the stem, said housing being movable in a generally linear direction between a forward position adjacent the seat support member and a rearward position spaced apart from said seat support member;
- whereby the backrest can tilt as a unit with the seat support member, move in a curvilinear path to a desired height and corresponding angular position, and move fore and aft to a desired overall position.
3 more elements
A backrest adjustment apparatus for use with a chair having a base structure and a seat mounted on a seat support member, the apparatus comprising:
- a backrest including an elongated stem having a curved lower portion;
- a backrest support member adjustably attached to a rear portion of the seat support member and adapted to slidably receive the curved portion of the stem, said backrest support member being movable between a forward position adjacent the seat support member and a rearward position spaced apart from said seat support member, thus providing fore and aft adjustment of the backrest;
- a latch mechanism adapted to lock the lower portion of the stem in a desired position;
- and
- an actuator member adapted to move the latch mechanism between an engaged and disengaged position;
- whereby disengagement of the latch mechanism allows the backrest stem to move in a curvilinear path to a desired height and corresponding angular position for the backrest, and whereupon reengagement of the latch mechanism locks the backrest stem in said position.
3 more elements
Dependencies are inferred from the claim text.