EP1576904A1 - A chair with oscillating backrest - Google Patents
A chair with oscillating backrest Download PDFInfo
- Publication number
- EP1576904A1 EP1576904A1 EP04425190A EP04425190A EP1576904A1 EP 1576904 A1 EP1576904 A1 EP 1576904A1 EP 04425190 A EP04425190 A EP 04425190A EP 04425190 A EP04425190 A EP 04425190A EP 1576904 A1 EP1576904 A1 EP 1576904A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- backrest
- chair
- oscillating
- oscillating element
- transverse element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47C—CHAIRS; SOFAS; BEDS
- A47C7/00—Parts, details, or accessories of chairs or stools
- A47C7/36—Support for the head or the back
- A47C7/40—Support for the head or the back for the back
- A47C7/44—Support for the head or the back for the back with elastically-mounted back-rest or backrest-seat unit in the base frame
- A47C7/443—Support for the head or the back for the back with elastically-mounted back-rest or backrest-seat unit in the base frame with coil springs
Definitions
- the invention relates to a chair comprising a base structure, a seat, a backrest and an elastic device that allows a rearwards oscillation of the backrest under the action of a rearwards thrust applied by the user, and in which the elastic device applies to the backrest an elastic force which tends to thrust the backrest towards a resting position against the rearwards thrust applied by the user.
- the backrest 16 is preferably constituted by a monolithic piece of injection moulded plastic material and is connected to the portion supporting the backrest 24 by means of an elastic device 26.
- the elastic device 26 comprises a stationary transverse element 28 fastened, at each of its ends, to the corresponding portion supporting the backrest 24.
- the transverse element 28 is preferably constituted by a metal bar, for example made of steel, having in a plan view an arched shape with concavity oriented towards the front part of the chair.
- the transverse element 28 has a rectangular transverse section and has at each end a fastening portion 30 fastened to the corresponding portion supporting the backrest 24.
- the fastening portion 30 is preferably constituted by a downwards bent portion of the transverse element 28.
- the fastening portion 30 is fastened to a bushing 32 by means of a transverse pivot 34.
- the bushing 32 is inserted and fastened in the open upper end of the supporting portion of the backrest 24.
- the bushing 32 is formed in two parts and is glued to the support portion 24.
Landscapes
- Chairs Characterized By Structure (AREA)
Abstract
A chair with oscillating backrest, comprising a
base structure (12), a seat (14), a backrest (16) and
an elastic device (26) which allows a rearward
oscillation of the backrest (16) under the action of a
rearwards thrust applied by the user, and in which the
elastic device (26) applies to the backrest an elastic
force which tends to thrust the backrest towards a
resting position against the rearward thrust applied by
the user.
The elastic device (26) comprises:
- a stationary transverse element (28) fastened to the base structure (12),
- an oscillating element (36) articulated to the transverse element (28) around a transverse horizontal axis (38), and
- elastic means (42) positioned between the stationary transverse element (28) and the oscillating element (36).
Description
- The present invention relates to a chair with oscillating backrest.
- More specifically, the invention relates to a chair comprising a base structure, a seat, a backrest and an elastic device that allows a rearwards oscillation of the backrest under the action of a rearwards thrust applied by the user, and in which the elastic device applies to the backrest an elastic force which tends to thrust the backrest towards a resting position against the rearwards thrust applied by the user.
- There are many types of chairs with oscillating backrest, provided with more or less complex mechanisms that allow to obtain a rearwards oscillation of the backrest and which produce an elastic reaction that contrasts the rearwards thrust applied by the user.
- The object of the present invention is to provide a chair with oscillating backrest provided with an elastic device that is particularly simple and has reduced cost.
- According to the present invention, said object is achieved by a chair having the characteristics set out in claim 1.
- The features and the advantages of the present invention shall become readily apparent from the detailed description that follows, provided purely by way of non limiting example, with reference to the accompanying drawings, in which:
- Figure 1 is a partially sectioned lateral view of a chair according to the present invention in resting position,
- Figure 2 is a lateral section view showing the backrest of the chair of Figure 1, in position of maximum rearwards inclination,
- Figure 3 is a partial section view in enlarged scale of the part designated by the arrow III in Figure 1,
- Figure 4 is a partial plan section view according to the line IV-IV of Figure 3, and
- Figure 5 is a partial front elevation view according to the arrow V of Figure 4.
- With reference to Figure 1, the
number 10 designates a chair according to the present invention, comprising abase structure 12, aseat 14 and abackrest 16. - The
base structure 12 comprises tworear legs 18, twofront legs 20 and twolateral elements 22 supporting theseat 14. Theseat 14 is fastened to thebase structure 12. - The
base structure 12 comprises portions for supporting thebackrest 24 which projects above the rear part of thechair 14. In the illustrated example, the supporting portions of thebackrest 14 are formed by extensions of the tworear legs 18. - The
backrest 16 is preferably constituted by a monolithic piece of injection moulded plastic material and is connected to the portion supporting thebackrest 24 by means of anelastic device 26. - With reference in particular to Figures 3, 4 and 5, the
elastic device 26 comprises a stationarytransverse element 28 fastened, at each of its ends, to the corresponding portion supporting thebackrest 24. Thetransverse element 28 is preferably constituted by a metal bar, for example made of steel, having in a plan view an arched shape with concavity oriented towards the front part of the chair. In the illustrated example, thetransverse element 28 has a rectangular transverse section and has at each end afastening portion 30 fastened to the corresponding portion supporting thebackrest 24. As shown in Figure 3, thefastening portion 30 is preferably constituted by a downwards bent portion of thetransverse element 28. The fasteningportion 30 is fastened to abushing 32 by means of atransverse pivot 34. Thebushing 32 is inserted and fastened in the open upper end of the supporting portion of thebackrest 24. Preferably, thebushing 32 is formed in two parts and is glued to thesupport portion 24. - The
elastic device 26 comprises an oscillatingelement 36 articulated to the stationarytransverse element 28. The oscillatingelement 26 has a cross section with a C profile facing the rear part of the chair and in plan view it has an arched shape with its concavity facing the front part of the chair. The oscillatingelement 26 extends in the transverse direction between the two support portions of thebackrest 24. The two opposite ends of the oscillatingelement 26 are articulated to the stationarytransverse element 28 around ahorizontal axis 38. As shown in particular in Figures 4 and 5, in correspondence with each end the oscillatingelement 26 has a cross section with a C shape oriented downwards and each of these ends is articulated to the stationarytransverse element 28 by means of apivot 40 that extends according to a horizontal and transverse direction coinciding with theaxis 38. Thearticulation pivot 40 is preferably situated above the corresponding supporting portion of thebackrest 24, in the area in which the stationarytransverse element 28 is bent by 90° to form thefastening portion 30 oriented downwards. The oscillatingelement 26 is free to oscillate relative to the stationarytransverse element 28 around the horizontaltransverse axis 38. - The
elastic device 26 comprises elastic means positioned between the stationarytransverse element 28 and the oscillatingelement 36 and tending to cause the oscillatingelement 26 to oscillate upwards and towards the front part of the chair relative to the stationarytransverse element 28. In the example illustrated in the figures, these elastic means comprise a plurality of helical springs incompression 42 positioned with their axes substantially parallel to each other and oriented according to substantially vertical directions. - As shown in particular in Figures 3 and 5, the lower ends of the
springs 42 act on a lowerretaining element 44, preferably made of plastic material provided withprojections 46 which are inserted within thesprings 42. The lower retaining element preferably has an inverse U section which is coupled with the upper part of the stationarytransverse element 28. The upper ends of thesprings 42 act on an upperretaining element 48 provided withprojections 50 which are inserted within thesprings 42. Theupper retaining element 50 is preferably provided on its lower face with pivot shaped projections (not shown) which engage corresponding holes (also not shown) provided on theupper wing 52 of the oscillatingelement 36. - The compressed
helical springs 42 tend to cause the forward oscillation of the oscillatingelement 36. In the resting position, the forward oscillation of the oscillatingelement 36 ends in the position in which thelower wing 54 of the oscillatingelement 36 comes to abut against the lower surface of the stationarytransverse element 28. Between the surfaces in mutual contact there may be interposed small pads made of elastomeric material (not shown). Thelower wing 54 of the oscillatingelement 36 thus forms an end stop which defines the position of maximum forward inclination of theelastic device 26. - The
elastic device 26 is also provided with a second end stop which limits the position of maximum rearward inclination of the elastic device. As shown in particular in Figure 4, this second end stop is preferably formed by a pair of downwards projecting tabs 52 (only one of which is shown in Figure 5) integrally formed with the upperretaining element 48, which bear against the upper surface of the stationarytransverse element 28 in the maximum rearwards inclination of theelastic device 26. - The
backrest 16 is fastened to the oscillatingelement 36 and is therefore free to oscillate together therewith around thetransverse axis 38 between the position of maximum forward inclination (resting position) illustrated in Figure 1 and the position of maximum rearward inclination illustrated in Figure 2. Thebackrest 16 has abearing surface 54 against which, in use, bears the user's back. In a section in a horizontal plane (Figure 4) thebearing surface 54 has an arched shape with concavity oriented towards the front part of the chair. In a section in a vertical plane (Figure 1 and 2) thebearing surface 54 has an arched shape with the convexity oriented towards the front part of the chair. - The
backrest 16 is preferably fastened to the oscillatingelement 36 with a snap-on system. As shown in Figures 3 and 4, in the rear part of thebackrest 16 is provided atransverse cavity 56 defined between twointegral walls transverse cavity 56 has such a shape as to receive within it theelastic device 26. The twowalls opening 62 through which theelastic device 26 is inserted in thecavity 56. The edges of theopening 62, designated by thereference numbers lower wing 54 of the oscillatingelement 36. The dimensions of thecavity 56 are such that thebackrest 16 is fastened without play to the oscillatingelement 36. - In the resting position shown in Figure 1 the
backrest 16 is in the position of maximum forward inclination. When the user applies a rearwards thrust to thebearing surface 54, thesprings 42 are compressed and thebackrest 16 oscillates backwards. The springs create an elastic reaction that contrasts the rearwards thrust applied by the user. The backward oscillating motion of thebackrest 16 ends when theend stop elements 52 of the oscillatingelement 26 come in contact with the stationarytransverse element 28. In this position, illustrated in Figure 2, thebackrest 16 is in the maximum rearwards inclination. When the rearwards thrust applied by the user on thebearing surface 54 ceases, thebackrest 16 automatically returns to the resting position under the action of thesprings 42.
Claims (10)
- A chair with oscillating backrest, comprising a base structure (12), a seat (14), a backrest (16) and an elastic device (26) that allows a rearwards oscillation of the backrest (16) under the action of a rearwards thrust applied by the user, and in which the elastic device (26) applies to the backrest an elastic force which tends to thrust the backrest towards a resting position against the rearwards thrust applied by the user,
characterised in that the elastic device (26) comprises:a stationary transverse element (28) fastened to the base structure (12),an oscillating element (26) articulated to the transverse element (28) around a transverse horizontal axis (38), andelastic means (42) positioned between the stationary transverse element (28) and the oscillating element (36). - A chair as claimed in claim 1, characterised in that the stationary transverse element (28) comprises a metal bar with an arched shape fastened to support portions of the backrest (24) projecting above the upper part of the seat (14).
- A chair as claimed in claim 2, characterised in that said support portions of the backrest (24) are formed by extensions of the rear legs (18) of the base structure (12).
- A chair as claimed in claim 3, characterised in that the oscillating element (36) has in plan form an arched shape with its concavity oriented towards the front part of the chair and is articulated at its own ends to the stationary transverse element (28) in correspondence with said support portions of the backrest (24).
- A chair as claimed in claim 4, characterised in that the oscillating element (36) has a substantially C shaped cross section oriented towards the rear part of the chair.
- A chair as claimed in claim 5, characterised in that said elastic means comprise a plurality of helical springs in compression (42) positioned with their axes oriented in substantially vertical direction.
- A chair as claimed in claim 6, characterised in that said helical springs in compression (42) act against an upper wing (52) of the oscillating element (36).
- A chair as claimed in claim 7, characterised in that the oscillating element (36) comprises a lower wing (54) which bears against a lower surface of the stationary transverse element (28) to define a first end stop position of the backrest (16).
- A chair as claimed in claim 8, characterised in that the oscillating element (36) bears a second end stop element (52) which bears against an upper surface of the stationary transverse element (28) to define a second end stop position of the backrest (16).
- A chair as claimed in claim 1, characterised in that the backrest (16) is fastened in snap-on fashion to the oscillating element (36).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP04425190A EP1576904A1 (en) | 2004-03-18 | 2004-03-18 | A chair with oscillating backrest |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP04425190A EP1576904A1 (en) | 2004-03-18 | 2004-03-18 | A chair with oscillating backrest |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1576904A1 true EP1576904A1 (en) | 2005-09-21 |
Family
ID=34833839
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP04425190A Withdrawn EP1576904A1 (en) | 2004-03-18 | 2004-03-18 | A chair with oscillating backrest |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP1576904A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4479679A (en) * | 1981-06-08 | 1984-10-30 | Steelcase Inc. | Body weight chair control |
US4703974A (en) * | 1984-10-23 | 1987-11-03 | Protoned B.V. | Seat furniture |
EP0249584A2 (en) * | 1986-06-12 | 1987-12-16 | PRO-CORD s.r.l. | Chair with hinged backrest |
US5964503A (en) * | 1997-04-28 | 1999-10-12 | Inoue Associates, Inc. | Chair |
US6149236A (en) * | 1996-10-14 | 2000-11-21 | Vitra Patents Ag | Chair frame, control mechanism and upholstery |
-
2004
- 2004-03-18 EP EP04425190A patent/EP1576904A1/en not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4479679A (en) * | 1981-06-08 | 1984-10-30 | Steelcase Inc. | Body weight chair control |
US4703974A (en) * | 1984-10-23 | 1987-11-03 | Protoned B.V. | Seat furniture |
EP0249584A2 (en) * | 1986-06-12 | 1987-12-16 | PRO-CORD s.r.l. | Chair with hinged backrest |
US6149236A (en) * | 1996-10-14 | 2000-11-21 | Vitra Patents Ag | Chair frame, control mechanism and upholstery |
US5964503A (en) * | 1997-04-28 | 1999-10-12 | Inoue Associates, Inc. | Chair |
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Effective date: 20060322 |