GB1582770A

GB1582770A - Chairs

Info

Publication number: GB1582770A
Application number: GB36987/77A
Authority: GB
Original assignee: Center for Design Research and Development NV
Current assignee: Center for Design Research and Development NV
Priority date: 1976-09-07
Filing date: 1977-09-05
Publication date: 1981-01-14
Also published as: FR2363301A2; SE432869B; DK158372B; DK158372C; AU2812077A; AT367991B; CH618331A5; CA1076944A; IT1112114B; JPS5349563A; DE2740072A1; MX144620A; FR2363301B2; AR224227A1; ES230752Y; NL7709160A; SE7709049L; BE858444R; ATA632177A; DK396377A

Abstract

TITLE - CHAIR The seat of a chair is mounted on a seatsupporting structure of the chair frame by means of closely spaced, parallel sleeves which extend lengthwise on the underside of the seat and which are received in telescoping and sliding relation by seat supports which are parts of a generally centrally located seat supporting structure of the chair frame. The front portion of the seat supporting structure is supported in cantilevered relation by the chair legs or pedestal. The chair back is mounted on a generally centrally located back support of the chair frame to tilt backward independently of the position of the seat from a resiliently restrained, relatively upright position to a backward, tilted position.

Description

(54) CHAIRS (71) We, CENTER FOR DESIGN RE SEARCH AND DEVELOPMENT N.V., a Cat- poration of the Netherlands Antilles, having a place of business at John B. Gorsiraweg 6, Curacao, Netherlands, Antilles, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to chairs, and particularly to chairs having a seat which is movable back and -forth, and a back which is mounted so that it pivots, independently of the movement of the seat, between upright and inclined positions.

The invention provides an improved or modified form of the chair described and claimed in our Patent Specification No.

1,501,765. Claim 1 of that specification relates to a chair comprising a frame including a pair of laterally spaced-apart back supports; a pair of laterally spaced-apart seat supports and means rigidly connecting the supports; a back mounted on the back supports; a seat mounted on the seat supports, the seat supports being of substantially uniform external cross-section throughout their length and the seat having a pair of laterally spaced-apart sleeves, each of which receives a corresponding one of the seat supports, each sleeve being of substantially uniform internal cross-section along its length and having an axis coincident with the axis of the seat support received therein and being slidable on the seat support such that the seat is slidable backward and forward on the seat supports; and Co- acting means on the seat and the seat supports for limiting the extent of movement of the seat on the seat supports.

A substantial improvement in comfort over chairs with fixed geometry may be afforded by the chair described above in so far as it allows the user to assume various sitting postures and the chair will conform thereto.

In chairs in which the seat has little or no padding, further comfort may be afforded if the seat supports and the sleeves are made upwardly concavely arcuate (i.e.

curved about a centre of curvature located some distance vertically above the coincident axes of the respective sleeves and seat supports) so that the rake of the seat increases, the further forward it is on the supports. In chair seats that are relatively heavily padded, the seat supports and sleeves need not be curved, in as much as the padding will provide comfortable support to a person sitting in the chair in all positions of forward and backward movement, even though the shifting of the seat to a more forward position, as the person leans back to a relaxed position in the chair, requires the imposition by the seat to the person of a greater horizontal force component so that the person does not have the feeling that he will slide off the seat.Heavy padding provides the necessary change in geometry that is present when curved sleeves and supports are used in lightly-padded or unpadded seats.

In the improved or modified form of chair in accordance with the present invention, the chair seat has on its underside a pair of closely spaced-apart elongate channels of uniform internal cross-section extending lengthwise generally in parallel vertical planes and is mounted on a generally centrally located seat-supporting structure of the chair frame, which seat-supporting structure has a generally centrally located lengthwise forwardly extending cantilevered portion and closely spaced-apart seat supports on the cantilevered portion of uniform external cross-section substantially matching the internal cross-section of the channels, the channels of the seat being received in telescoping and sliding relation on the seat supports of the seat-supporting structure such that the seat is slidable backward and forward; and the back is mounted on.a generally centrally located back support of the chair frame to tilt backward in dependently of the position of the seat from a resiliently urged relatively upright position to a backward tilted position.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figs. 1 and 2 are side elevational and front elevational views, respectively, of a chair according to the present invention Fig. 3 is a side cross-sectional view of the seat supporting structure of the chair taken on a line 3-3 of Fig. 2; Fig. 4 is a top cross-sectional view of the seat supporting structure taken generally along a line 4-4 of Fig. 3 and in the direction of the arrows; Figs. 5 to 9 are cross-sectional views of the seat supporting structure taken along lines sol5, 6-6, 7-7, 8-8, and 9-9, respectively, of Fig. 3 in the direction of the arrows; Fig. 10 is a side cross-sectional view of the back of the chair taken generally along a line 10-10 of Fig. 2 and in the direction of the arrows; and Fig. 11 is a fragmentary cross-sectional view of the back mounting structure taken along a line 11-11 of Fig. 10 and in the direction of the arrows.

In the illustrated embodiment of the invention, a chair, as shown in Figs. 1 to 11, has a five-legged pedestal base 400 which supports, at the height of a chair seat, a generally "L"-shaped (as viewed from the side) frame assembly 402. The frame assembly includes a tubular piece 404 of generally rectangular cross-section bent to provide a generally vertical leg 406 which supports the back 408 of the chair, and a generally horizontal leg 410 which receives telescopically a tongue 412 (Figs. 3 and 4) which extends rearwardly from a seat sup porting structure 414.

Referring to Figs. 3 to 9, the seat supporting structure 414 comprises a main body portion 416 which extends lengthwise of the chair and has a dependent boss 418 that receives a post 420 of the pedestal base 400 (Figs. 3 and 6). The seat supporting structure 414 has extending longitudinally along each side and projecting outwardly a pair of laterally spaced-apart flanges forming seat supports 422, each of which receives an elongate, generally cup-shaped anti-friction bearing element 424, for example, an element made of polytetrafluoroethylene or nylon. The seat supports 422 are received in telescoping relation within a pair of laterally spaced-apart channels 426 that extend lengthwise under the chair seat 428, the channels being defined by a mounting unit 430 which is fastened, such as by screws 432 (Fig. 9), to bosses 434 moulded on the underside of the seat 428.The mounting unit 430 is assembled, such as by rivets 436 (Fig. 8), from a plate 438 which abuts the underside of the seat 428 and a pair of elongate members 440 of generally "Z"-shaped cross-section. The channels 426 defined by the plate 438 and the members 440 receive telescopically the seat supports 422 with a clearance adequate to permit the seat to slide relatively freely backward and forward on the seat supports.

The seat 428 is spring-loaded toward the rearwardmost position (the position shown in Figs. 3 to 9) by a coil spring 442 connected under tension between a pin 444 that extends up into a cavity 446 formed in the body portion 416 of the seat supporting structure 414 and a pin 448 that projects down into the cavity 446 from the plate 438 of the mounting unit 430. The limit position of backward movement of the seat 428 is established by engagement of a rubber bumper 450 that is mounted on a rib 452 extending down from the plate 438 with a pair of ribs 454 on the body portion 416 of the seat supporting structure that define the rear wall of a second cavity 447. The forward limit position is established by engagement of the rubber bumper 450 with the front wall 456 of the second cavity 447.A passage 454a connects the two cavities and allows the pin 448 and the front end of the spring 442 to move between the two cavities.

-As best seen in Figs. 10 and 11, the back 408 of the chair is mounted on an extension 458 of the back support portion 404 by means of a coupling 460 that is received telescopically in the back support portion 404 with a clearance that permits it to be slid up and down to adjust the height of the back 408. The back is locked at the desired height by a locking screw 462.

The extension 458 is received in a sleeve 464 moulded into the back wall of the chair back 408, and the back 408 is mounted to tilt between the relatively upright position shown in Fig. 10 and an inclined position (not shown) by a pivot coupling that is provided by an axle 466 which extends through holes in the extension 458 and in the sleeve 464. The back is springloaded into the relatively upright position by a torsion spring 468 of generally the mousetrap type.

The forward or upright limit position of tilting of the back 408 is established by engagement between the upper part of the back face of the extension 458 and the inside face of the back wall of the sleeve 464 in the region 470, and by engagement between the upper end of the front face of the extension 458 and the part of the back face of the chair back 408 adjacent thereto. The rearward or inclined limit position of the tilting of the back 408 is established by engagement of the part of the back of the chair within the sleeve 464 with the upper edges 472 of the side walls of the extension 458, which are cut at an angle to provide the desired limit of tilting of the back.The lower end of the back wall of the sleeve 464 angles away from the extension 458 to accommodate rearward tilting of the back and may engage the back wall of the extension 458, further to assist in supporting the back at the limit of inclined tilting.

The chair described above and shown in the drawings operates on the principle of independent forward and backward movement of the seat and tilting of the back, such that the chair will automatically adopt a configuration that will provide excellent anatomical support to a person sitting in the chair. The chair provides optimal distribution of body weight and excellent sacrolumbar support in all configurations.

When a person sitting in the chair sits upright, the seat will be in the rearward position and the back in an upright position.

When the person wants to lean back into a relaxed position in the chair, the seat will slide forward and the back will incline, such adjustments in the configuration of the chair being substantially solely responsive to the sitting posture of the individual.

Except in those cases when the seat is heavily padded, the increased rake of the seat plays an important role in supporting the body properly when the person relaxes back in the chair.

WHAT WE CLAIM IS: - 1. A chair, comprising either legs or a pedestal; a frame mounted on the legs or pedestal; and a seat and a back mounted separately on the frame, wherein the seat has on its underside a pair of closely spacedapart elongate channels of uniform internal cross-section extending lengthwise generally in parallel vertical planes and is mounted on a generally centrally located seat-supporting structure of the chair frame, which seat-supporting structure has a generally centrally located lengthwise forwardly extending cantilevered portion and closely spaced-apart seat supports on the cantilevered portion of uniform external cross-section substantially matching the internal cross-section of the channels, the channels of the seat being received in telescoping and sliding relation on the seat supports of the seat-supporting structure such that the seat is slidable backward and forward; and wherein the back is mounted on a generally centrally located back support of the chair frame to tilt backward independently of the position of the seat from a resiliently urged relatively upright position to a backward tilted position.

2. A chair according to Claim 1, wherein the seat supports comprise flanges which extend lengthwise along and generally outwardly from the sides of the seat supporting structure.

3. A chair according to Claim 1 or Claim 2, including an upwardly open cavity in the seat supporting structure containing a spring which is connected between the seat supporting structure and the seat to urge the seat rearwardly on the seat supporting structure.

4. A chair according to Claim 1 or Claim 2, including an upwardly open cavity in the seat supporting structure, and a member on the underside of the seat projecting into the cavity and engageable with front and back walls of the cavity upon forward and rearward movement, respectively, of the seat on the seat supporting structure, thereby to limit forward and rearward movement of the seat on the seat supporting structure.

5. A chair according to Claim 4, including a second upwardly open cavity in the seat supporting structure located rearwardly of the aforementioned cavity; a passage between the cavities; and a spring connected between the seat and the seat supporting structure and normally received within the second cavity when the seat is in the rearward position, the spring also extending through the passage between the cavities upon extension thereof when the seat moves forward on the seat supporting structure.

6. A chair according to any preceding claim, wherein the back is mounted on the back support by an articulating structure having a first part secured to the upper end of the back support and a second part secured to the back.

7. A chair according to any one of Claims 1-5, wherein the back is mounted on the back support by means of an axle coupling the back to the back support for pivotal movement of the back.

8. A chair according to Claim 7, wherein the back has a sleeve which receives the upper end of the back support, and the sleeve and the upper end of the back support have interengaging surfaces which limit the extent of pivotal movement of the back.

9. A chair according to Claim 8, including a torsion spring associated with the axle and coacting between the back and back support to urge the back to an upright position.

10. A chair according to Claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. by engagement of the part of the back of the chair within the sleeve 464 with the upper edges 472 of the side walls of the extension 458, which are cut at an angle to provide the desired limit of tilting of the back. The lower end of the back wall of the sleeve 464 angles away from the extension 458 to accommodate rearward tilting of the back and may engage the back wall of the extension 458, further to assist in supporting the back at the limit of inclined tilting. The chair described above and shown in the drawings operates on the principle of independent forward and backward movement of the seat and tilting of the back, such that the chair will automatically adopt a configuration that will provide excellent anatomical support to a person sitting in the chair. The chair provides optimal distribution of body weight and excellent sacrolumbar support in all configurations. When a person sitting in the chair sits upright, the seat will be in the rearward position and the back in an upright position. When the person wants to lean back into a relaxed position in the chair, the seat will slide forward and the back will incline, such adjustments in the configuration of the chair being substantially solely responsive to the sitting posture of the individual. Except in those cases when the seat is heavily padded, the increased rake of the seat plays an important role in supporting the body properly when the person relaxes back in the chair. WHAT WE CLAIM IS: -

1. A chair, comprising either legs or a pedestal; a frame mounted on the legs or pedestal; and a seat and a back mounted separately on the frame, wherein the seat has on its underside a pair of closely spacedapart elongate channels of uniform internal cross-section extending lengthwise generally in parallel vertical planes and is mounted on a generally centrally located seat-supporting structure of the chair frame, which seat-supporting structure has a generally centrally located lengthwise forwardly extending cantilevered portion and closely spaced-apart seat supports on the cantilevered portion of uniform external cross-section substantially matching the internal cross-section of the channels, the channels of the seat being received in telescoping and sliding relation on the seat supports of the seat-supporting structure such that the seat is slidable backward and forward; and wherein the back is mounted on a generally centrally located back support of the chair frame to tilt backward independently of the position of the seat from a resiliently urged relatively upright position to a backward tilted position.