US4451085A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chair
Assignee: WILKHAHN AND HAHNE GmbH AND Co
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Filing: 1981-03-17
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Granted: 1984-05-29
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Expires: 2001-03-17
Abstract
Abstract A reclining article of furniture for sitting, especially an office chair, with the article including a seat portion and a back portion articulated thereto. The seat portion and back portion are respectively connected to an underframe. The seat portion is supported in a forward zone and the back portion is supported by a supporting lever articulated to the underframe and articulated to the back portion at hip level of a user. To obtain a support which is also effective in the zone of the lumbodorsal vertebrae and to provide a close contact of the supporting surfaces with the users body. The contact is uniform in the rest position approximately from a back of the knees up to the shoulder blades. The seat and back merge through an arcuate intermediate section which is flexible so that the arc becomes wider. A connecting line extending between two points of articulation of the supporting lever in a basic position of the chair is inclined at an angle of between 0° and 25° and, preferably, between 15° and 25°, with respect to the vertical. By virtue of these features, the seat surface is initially lengthened toward a rear before a stronger rearward inclination of the back occurs when the seat is moved from an upright sitting attitude to a reclined attitude.
Inventors
- 👤 Klaus Franck
- 👤 Werner Sauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:39
CPC Classifications
A; A47; A47C; A47C1/00; A47C1/02; A47C1/031; A47C1/032; A47C1/03255; A47C1/03261; A47C1/03266; A47C1/03272; A47C1/03277; A47C1/03279
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
210 words
A reclinable article of sitting furniture comprising a support means for supporting the article, a seat portion, a back portion, means for mounting a forward area of the seat portion on the support means, and lever means for mounting the back portion on the support means, the lever means has a first end articulated to the back portion and a second end articulated to the support means, characterized in that an arcuate flexible intermediate means is interposed between the seat portion and the back portion connecting the seat and back portions together, the flexible intermediate means is adapted to be flexed such that the arc becomes wider when the intermediate means is flexed, the first end of the lever means is articulated to the back portion at approximately hip level of a user of the article, the second end of the lever means is articulated to the support means at a point below and approximately at a center of the seat portion, and in that a line connecting the points of articulation of the lever means to the back portion and support means subtends, with respect to a vertical plane, a predetermined angle in the range of between 0° and 25° when the article is in a basic upright position.
Claim 2
Dependent Claim
210 words
A reclinable article of sitting furniture comprising a support means for supporting the article, a seat portion, a back portion, means for mounting a forward area of the seat portion on the support means, and lever means for mounting the back portion on the support means, the lever means has a first end articulated to the back portion and a second end articulated to the support means, characterized in that an arcuate flexible intermediate means is interposed between the seat portion and the back portion connecting the seat and back portions together, the flexible intermediate means is adapted to be flexed such that the arc becomes wider when the intermediate means is flexed, the first end of the lever means is articulated to the back portion at approximately hip level of a user of the article, the second end of the lever means is articulated to the support means at a point below and approximately at a center of the seat portion, and in that a line connecting the points of articulation of the lever means to the back portion and support means subtends, with respect to a vertical plane, a predetermined angle in the range of between 0° and 25° when the article is in a basic upright position.
Claim 3
Dependent Claim
21 words
An article according to claim 1, characterized in that the means for mounting the seat portion is a pivot joint means.
Claim 4
Dependent Claim
21 words
An article according to claim 2, characterized in that the predetermined angle is in the range of between 15° and 25°.
Claim 5
Dependent Claim
49 words
An article according to one of claims 2 or 3, characterized in that, in a vertical longitudinal section, the back portion is curved convexly toward the seat portion, and in that a lower half of the back portion is inclined forwardly in the basic upright position of the article.
Claim 6
Dependent Claim
63 words
An article according to claim 4, characterized in that a distance between the points of articulation of the first and second ends of the lever means is about twice as large as a distance between the point of articulation of the second end of the lever means and the mounting point of the forward area of the seat portion to the support means.
Claim 7
Dependent Claim
40 words
An article according to claim 5, characterized in that the points of articulation of the lever means and mounting point in a basic position of the article are arranged such that a line connecting the points define an acute triangle.
Claim 8
Dependent Claim
72 words
An article according to claim 6, characterized in that the mounting point is disposed rearwardly of a forward edge of the seat portion by a distance equal to about one quarter of depth of the seat portion, and in that about one-third of a forward part of the seat portion is bent downwardly to a greater extent than the forward edge is pivoted upwardly during a rearward swinging of the seat portion.
Claim 9
Dependent Claim
32 words
An article according to claim 7, characterized in that the articulation point of the second end of the lever means is offset toward a rear of a center of the seat portion.
Claim 10
Dependent Claim
22 words
An article according to claim 8, characterized in that the offset is approximately ten percent of the depth of the seat portion.
Claim 11
Dependent Claim
64 words
An article according to claim 8, characterized in that, in a horizontal section, the back portion is curved concavely with respect to the seat portion, means are provided in the back portion for supporting a small of a back of the user, and in that the point of articulation of the first end of the lever means are disposed at the back supporting means.
Claim 12
Dependent Claim
23 words
An article according to claim 10, characterized in that the back supporting means is a forwardly curved bulge provided in the back portion.
Claim 13
Dependent Claim
24 words
An article according to claim 10, characterized in that the seat portion, back portion, and intermediate means are formed as a one piece shell.
Claim 14
Dependent Claim
17 words
An article according to claim 12, characterized in that the shell is formed of a synthetic resin.
Claim 15
Dependent Claim
49 words
An article according to claim 12, characterized in that the pivot joint means includes semicylindrical bearings having a snap rim moulded to the shell in the forward area of the seat portion, and a horizontally extending bearing axle means mounted on the support means and accommodated in the bearings.
Claim 16
Dependent Claim
51 words
An article according to claim 12, characterized in that means are connected to the pivot joint means and to a point of articulation of the first end of the lever means for providing a force for enabling a restoring of the article from a reclined position to the basic upright position.
Claim 17
Dependent Claim
28 words
An article according to claim 15, characterized in that the force providing means includes a pair of elastic arm rests disposed on respective sides of the seat portion.
Claim 18
Dependent Claim
43 words
An article according to claim 10, characterized in that the seat portion and back portion each include a separate supporting frame, and in that the intermediate means includes elastic connecting members for connecting respective lateral sides of the support frames to each other.
Claim 19
Dependent Claim
43 words
An article according to claim 17, characterized in that means are at least one of directly and indirectly connected to the lever means for providing a force for enabling a restoring of the article from the reclined position to the basic upright position.
Claim 20
Dependent Claim
18 words
An article according to claim 18, characterized in that the force providing means is a restoring spring means.
Claim 21
Dependent Claim
18 words
An article according to claim 19, characterized in that means are provided for adjusting the force providing means.
Claim 22
Dependent Claim
22 words
An article according to claim 20, characterized in that means are provided for locking the lever means in a basic upright position.
Claim 23
Dependent Claim
44 words
An article according to claim 21, characterized in that the restoring spring means is a torsion rod means for forming the articulation point of the second end of the lever means, and in that cam means are provided for pretensioning the torsion rod means.
Claim 24
Dependent Claim
35 words
An article according to claim 21, characterized in that the restoring spring means includes at least one coil spring, and in that cam means are provided for pretensioning the at least one coil spring means.
Claim 25
Dependent Claim
34 words
An article according to claim 21, characterized in that the restoring spring means includes at least one leaf spring, and in that cam means are provided for pretensioning the at least one leaf spring.
Claim 26
Dependent Claim
30 words
An article according to claim 21, characterized in that the restoring spring means is a pneumatic spring, and in that cam means are provided for pretensioning the pneumatic spring means.
Claim 27
Dependent Claim
48 words
An article according to one of claims 1, 2, or 3, characterized in that the seat portion and back portion each include a separate supporting frame, and in that the intermediate means includes elastic connecting members for connecting respective lateral sides of the supporting frames to each other.
Claim 28
Dependent Claim
37 words
An article according to claim 26, characterized in that means are connected to the supporting lever means for providing a force for enabling a restoring of the article from a reclined position to the basic upright position.
Claim 29
Dependent Claim
18 words
An article according to claim 27, characterized in that the force providing means is a restoring spring means.
Claim 30
Dependent Claim
22 words
An article according to claim 28, characterized in that means are provided for locking the lever means in a basic upright position.
Claim 31
Dependent Claim
42 words
An article according to one of claims 1, 2, or 3, characterized in that means are connected to the supporting lever means for providing a force for enabling a restoring of the article from a reclined position to the basic upright position.
Claim 32
Dependent Claim
69 words
An article according to one of claims 1, 2, or 3, characterized in that, in a horizontal section, the back portion is curved concavely with respect to the seat portion, means are provided in the back portion for supporting a small of a back of the user, and in that the point of articulation of the first end of the lever means are disposed at the back supporting means.
Claim 33
Dependent Claim
24 words
An article according to claim 31, characterized in that the seat portion, back portion and intermediate means are formed as a one piece shell.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-29 | 1987-11-28 | 1988-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-29 | 1991-11-28 | 1992-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-29 | 1995-11-28 | 1996-05-29 | $7700.00 | Window Closed / Lapsed |