Tilt control mechanism for chair
First Claim
1. A chair comprising:
- a base;
a deformable seat member positioned above the base and having an occupant-deformable upper surface disposed for engagement with a chair occupant, said seat member being mounted on a seat frame;
a back member projecting upwardly from adjacent a rear edge of the seat member;
a rigid upright structure connected to said base for vertical pivoting movement about a first substantially horizontal pivot axis which is positioned below said seat member and extends transversely relative thereto, said upright structure including an upright part which projects upwardly adjacent the rear edge of said seat member and which mounts said back member thereon;
a pivot structure connected between said seat frame and said upright structure for permitting said seat member to pivot relative to said upright structure about a second substantially horizontal axis which is generally parallel with but displaced upwardly and rearwardly from said first axis, said second axis being positioned at an elevation at or only a small distance below the upper surface of the seat member when the seat member is not deformed by a seated occupant; and
a control linkage connected between said base, said seat frame and said upright structure for causing the seat member to tilt relative to the upright structure in one rotational direction about said second axis in response to rearward tilting of said upright structure in the opposite rotational direction about said first axis;
said control linkage including an elongate rigid control link which at one end is solely pivotally connected to said base and at the other end is connected to said upright structure for relative pivoting and translating movement therebetween, and a spring unit cooperating between said seat frame and said other end of said control link for permitting the seat frame to rotate relative to said upright structure in said one rotation direction when the upright structure is tilted rearwardly in said opposite rotational direction.
4 Assignments
0 Petitions
Accused Products
Abstract
A chair back is supported on a rigid upright coupled to a horizontal tilt shaft disposed under the front of the chair seat and supported on a control housing fixed to a pedestal. A tension mechanism urges the upright into an upright position. The chair seat is movably supported on the upright by an arrangement which permits the seat to pivot about a transverse horizontal axis positioned adjacent the upper surface of the seat. A control link is pivoted at one end to the control housing, and the other end has lost-motion pivotal connections to the seat frame and the upright. The lost-motion pivotal connection to the seat frame including a spring cooperating between the upright and the seat frame to allow the seat to move relative to the upright.
123 Citations
15 Claims
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1. A chair comprising:
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a base; a deformable seat member positioned above the base and having an occupant-deformable upper surface disposed for engagement with a chair occupant, said seat member being mounted on a seat frame; a back member projecting upwardly from adjacent a rear edge of the seat member; a rigid upright structure connected to said base for vertical pivoting movement about a first substantially horizontal pivot axis which is positioned below said seat member and extends transversely relative thereto, said upright structure including an upright part which projects upwardly adjacent the rear edge of said seat member and which mounts said back member thereon; a pivot structure connected between said seat frame and said upright structure for permitting said seat member to pivot relative to said upright structure about a second substantially horizontal axis which is generally parallel with but displaced upwardly and rearwardly from said first axis, said second axis being positioned at an elevation at or only a small distance below the upper surface of the seat member when the seat member is not deformed by a seated occupant; and a control linkage connected between said base, said seat frame and said upright structure for causing the seat member to tilt relative to the upright structure in one rotational direction about said second axis in response to rearward tilting of said upright structure in the opposite rotational direction about said first axis; said control linkage including an elongate rigid control link which at one end is solely pivotally connected to said base and at the other end is connected to said upright structure for relative pivoting and translating movement therebetween, and a spring unit cooperating between said seat frame and said other end of said control link for permitting the seat frame to rotate relative to said upright structure in said one rotation direction when the upright structure is tilted rearwardly in said opposite rotational direction. - View Dependent Claims (2, 3, 4)
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5. A chair comprising:
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a base; a deformable seat member positionable above said base and having an occupant-deformable upper surface disposed for engagement with a chair occupant, said seat member being mounted on a seat frame; a back member projecting upwardly from adjacent a rear edge of the seat member; a rigid upright structure connected to said base for vertical pivoting movement about a first substantially horizontal pivot axis which is positioned below a front portion of said seat member and extends transversely thereto, said upright structure including a lower lever part which at a forward end is pivotally joined to said base for pivoting about said first pivot axis and which projects rearwardly beneath the seat member and at a rearward end thereof is rigidly joined to an upright part which projects upwardly adjacent the rear edge of said seat member and which mounts said back member thereon; a motion-permitting structure connected between said seat frame and said upright structure for permitting said seat member to move relative to said upright structure; and a control linkage connected between said base, said upright structure and said seat frame for causing the seat member and its seat frame, when the upright structure is tilted rearwardly and downwardly about said first pivot axis, to synchronously tilt rearwardly with the upright structure but at a lesser tilt rate; said control linkage including an elongate control link which at a front end is supported on said base for pivoting about a second transverse axis, said control link projecting rearwardly and at a rearward end thereof being pivotally joined at a third transverse axis to a rearward end of an elongate compression spring, said compression spring being elongate forwardly from said third axis and at a forward end thereof being supportingly seated on said seat frame, said control linkage also including a guide member coupled to the rear end of said control link at said third pivot axis and disposed in front-to-back moving guided engagement with the lower lever part of said upright structure, whereby downward rearward tilting of said upright structure about said first axis causes a corresponding tilting of said seat frame and said seat member mounted thereon through a smaller angle and causes compression of said spring; and a biasing device cooperating with the upright structure for normally urging the upright structure and the back member mounted thereon into an upright position. - View Dependent Claims (6, 7, 8)
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9. A chair comprising:
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a base; a seat member positioned above said base and mounted on a seat frame; a back member projecting upwardly from adjacent a rear edge of the seat member; a rigid upright structure connected to said base for vertical pivoting movement about a first substantially horizontal pivot axis which is positioned below a front portion of said seat member and extends transversely relative thereto, said upright structure including an upright part which projects upwardly adjacent the rear edge of said seat member and which mounts said back member thereon; a pivot structure connected between said seat frame and said upright structure for permitting said seat member to pivot relative to said upright structure about a second substantially horizontal axis which is generally parallel with but displaced upwardly and rearwardly from said first axis; a control linkage connected between said base, said seat frame and said upright structure for causing the seat member and said seat frame, when the upright structure is tilted rearwardly and downwardly about said first pivot axis, to synchronously tilt rearwardly with the upright structure but at a lesser tilt rate, said control linkage including an elongate control link which at one end thereof has solely a first pivot connection to said base defining a third transverse pivot axis which is stationarily positioned relative to said first axis and at the other end thereof has first and second lost-motion pivotal connections to said seat frame and said upright structure respectively, said first and second lost-motion pivotal connections defining a fourth transverse pivot axis which extends generally parallel with said first pivot axis; said first lost-motion pivotal connection cooperating with said seat frame for permitting the seat frame to pivot a limited amount relative to said upright structure about said second axis to permit limited lowering of the front portion of the seat member; and said second lost-motion pivotal connection cooperating with said upright structure for permitting said fourth pivot axis to move transversely relative to said upright structure as the control link is swingably moved about said third axis due to occupant induced swinging of said upright structure about said first axis. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification