EP0032839B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Chair shells
Assignee: Individual
•
Filing: 1981-01-20
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Granted: 1984-05-16
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Expires: 2001-01-20
Abstract
Abstract A chair shell of resilient material such as polypropylene comprises a back support 12 and a seat portion 14. The natural deformability of the back support 12 is modified by slits 22, 24 and holes 32, 34, 36 so that under pressure from the back of a sitter resting against the back support the support is resiliently deformed into a shape which, in vertical section, includes a convex curve positioned properly to support the sitter's spine in the lumbo-sacral region and which is horizontal in convex section. The deformability of seat 14 is modified by slits 42, 44 and holes 42,46,48,50,54 to provide softer rear and front zones 44 and 52 to reduce the pressure on the ischial tuberosities and lower thighs of the sitter. The chair shell provides comfortable and orthopaedically desirable support whilst avoiding the need for thick upholstery. The undeformed state of the chair shell may be designed to allow the chairs to be easily stacked.
Inventors
- 👤 Bernard Curtis Watkin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 11:04
CPC Classifications
A; A47; A47C; A47C7/00; A47C7/02; A47C7/024; A47C3/00; A47C3/12; A47C7/029; A47C7/36; A47C7/40; A47C7/405; A47C7/46; Y; Y10; Y10S; Y10S297/00; Y10S297/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
324 words
A chair shell of resilient material comprising a back support (12) and a seat (14), the back support (12) in its undeformed state having a shape which, seen from the front, is flat or slightly convex in vertical section and is flat or slightly concave in horizontal section, the back support (12) having an upper part which, when flexed under pressure from the back of a sitter is resiliently deformed to increase the convexity in vertical section and the concavity in horizontal section of the back support (12), 99 ' characterised in that the upper part of the back support (12) has zones of weakness arranged to modify the deformability of the back support (12) so as to control the resilient deformation of the upper part of the back support (12) under pressure from the back of a sitter, whereby the deformed shape of the back support includes, in vertical section, a convex curve positioned to support the sitter's spine in a convex curve in the lumbo-sacral region, the chair shell has an opening (16) at the junction of the back support (12) and seat (14), the back support (12) has a lower part divided into two portions (26) by a centrally disposed slit (24) which extends upwards from the opening (16), the two portions (26) being adapted to flex resiliently under pressure from the back of a sitter in such a manner that the lower edges of the two portions (26) move backwards to increase the convexity of the back support (12) in vertical section and the inner edges of the two portions (26) move backwards to increase the concavity of the back support (12) in horizontal section, and in that the seat (4) has a rear portion (44) adapted to be deformed resiliently downwards under pressure from the ischial tuberosities of the sitter, and a front portion (52) adapted to be deformed resiliently downwards under pressure from the under-thighs of the sitter.
Claim 2
Dependent Claim
324 words
A chair shell of resilient material comprising a back support (12) and a seat (14), the back support (12) in its undeformed state having a shape which, seen from the front, is flat or slightly convex in vertical section and is flat or slightly concave in horizontal section, the back support (12) having an upper part which, when flexed under pressure from the back of a sitter is resiliently deformed to increase the convexity in vertical section and the concavity in horizontal section of the back support (12), 99 ' characterised in that the upper part of the back support (12) has zones of weakness arranged to modify the deformability of the back support (12) so as to control the resilient deformation of the upper part of the back support (12) under pressure from the back of a sitter, whereby the deformed shape of the back support includes, in vertical section, a convex curve positioned to support the sitter's spine in a convex curve in the lumbo-sacral region, the chair shell has an opening (16) at the junction of the back support (12) and seat (14), the back support (12) has a lower part divided into two portions (26) by a centrally disposed slit (24) which extends upwards from the opening (16), the two portions (26) being adapted to flex resiliently under pressure from the back of a sitter in such a manner that the lower edges of the two portions (26) move backwards to increase the convexity of the back support (12) in vertical section and the inner edges of the two portions (26) move backwards to increase the concavity of the back support (12) in horizontal section, and in that the seat (4) has a rear portion (44) adapted to be deformed resiliently downwards under pressure from the ischial tuberosities of the sitter, and a front portion (52) adapted to be deformed resiliently downwards under pressure from the under-thighs of the sitter.
Claim 3
Dependent Claim
49 words
A chair shell as claimed in claim 1, characterised in that the lower part of the back support (12) is formed with further slits (22) extending upwardly from the opening (16) and positioned on either side of the centrally disposed slit (24) near the sides of the back support.
Claim 4
Dependent Claim
49 words
A chair shell as claimed in claim 1 or claim 2, characterised in that a line of weakness (28) is formed in the back support (12) which extends horizontally across the back support (12) at the junction of the upper part and lower part of the back support (12).
Claim 5
Dependent Claim
49 words
A chair shell as claimed in any preceding claim, characterised in that the rear portion of the seat (14) is divided into two independently movable portions (44) by a slit (42) extending forwards from the opening (16) at the junction of the seat (14) and the back support (12).
Claim 6
Dependent Claim
40 words
A chair shell as claimed in claim 4, characterised in that each of the two independently movable portions (44) of the seat (14) is formed with an aperture (48) positioned to relieve pressure on the ischial tuberosities of the sitter.
Claim 7
Dependent Claim
43 words
A chair shell as claimed in any preceding claim, characterised in that in which each of the two portions (26) of the lower part of the back support (12) is formed with an aperture (30) to increase the softness of said portion (26).
Claim 8
Dependent Claim
55 words
A chair shell as claimed in any preceding claim, in that the upper part of the back support (12) is formed with two lines of weakness (34, 36) extending from a point near the centre of the back support (12) to points near the upper right and left corners respectively of the back support (12).
Claim 9
Dependent Claim
34 words
A chair shell as claimed in any preceding claim, characterised in that the back support (12) in its undeformed state has a shape which is convex in vertical section and concave in horizontal section.
Claim 10
Dependent Claim
40 words
A chair shell as claimed in any preceding claim, characterised in that the zones of weakness in the back support (12) comprise lines of weakness including lines of holes (28, 32, 34, 36, 38) formed in the back support (12).
Claim 11
Dependent Claim
23 words
A chair shell as claimed in any preceding claim, characterised in that the material of the chair shell is a crystalline propylene polymer.
Claim 12
Dependent Claim
28 words
A chair shell as claimed in claim 10, characterised in that the material is a homopolymer or copolymer of propylene with up to 18% by weight of ethylene.
Claim 13
Dependent Claim
19 words
A chair comprising a chair shell (10) as claimed in any preceding claim fixed to a supporting frame (60).
References Cited (Backward Citations)
GB1294091A
Cited
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