GB2257033A

GB2257033A - Chairs

Info

Publication number: GB2257033A
Application number: GB9213370A
Authority: GB
Inventors: Giampietro Zappa
Original assignee: NORMALIEN Srl
Current assignee: NORMALIEN Srl
Priority date: 1991-06-25
Filing date: 1992-06-24
Publication date: 1993-01-06
Also published as: GB9213370D0; DE4220332A1; FR2678150A1; ES2060507R; ES2060507B1; ES2060507A2

Description

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TITLE chairs DESCRIPTION The invention relates to adjustable chairs, such as are commonly used in offices.

Chairs are known to have apparatus f or adjusting the height and inclination of a seat. The apparatus is generally between a chair base, possibly provided with wheels, and the seat, which is attached to a seat f rame of the apparatus. The apparatus typically has an individual mechanism dedicated to controlling each of the height and inclination of the seat. The mechanisms are usually lever operated, and each mechanism requires an individual lever. Adjustment of both the height and inclination of a seat involves the separate operation of each of the individual levers. In practical terms, this means that a person seated in the chair has to use both hands to make adjustments. Furthermore, two separate mechanisms may cause difficulties in housing the respective components.

These problems were addressed in our British Patent specification No. 2252904, which provided a single mechanism for adjusting seat height and inclination under the control of a single handle. The space saved in housing the components now enables us to introduce a mechanism for adjusting the rake of the backrest independently of the inclination of the seat. In addition we describe a backrest frame adapted for syncronous movement with the seat.

The invention provides a chair comprising a seat frame and a backrest frame, each mounted on a housing which contains means including a first fluid cylinder for adjusting the height of the seat frame and for maintaining a selected height thereof, means including a second fluid cylinder for adjusting the inclination of the seat frame and for maintaining a selected inclination thereof, means including a third fluid cylinder for adjusting the rake of the backrest frame and for maintaining a selected rake thereof, a f irst member moveable to operate one of the first, second and third f luid cylinders, and a second member moveable to operate, independently of each other, the other two of the f irst, second and third fluid cylinders.

The invention further provides a chair comprising a seat frame and a backrest frame, each mounted on a housing which contains means including a first fluid cylinder for adjusting the height of the seat frame and f or maintaining a selected height thereof, means including a second f luid cylinder for adjusting the inclination of the seat frame and for maintaining a selected inclination thereof, and a member moveable to operate, independently of each other, the f irst and second fluid cylinders, the backrest frame being pivotally connected to the housing and connected to and spaced from the seat frame by a link hinged at both ends.

The invention is illustrated by the drawings of which:

Figure 1 is a side elevation of a chair including apparatus according to the invention; Figure 2 is a side elevation of another chair including apparatus according to the invention; Figure 3 is a sectional view of the apparatus of Figure 1, taken along the line A-A in Figure 5; Figure 4 is a sectional view of the apparatus of Figure 2, taken along the line B-B in Figure 6; Figure 5 is a part sectional top view of the apparatus of Figures 1 and 3, with some parts shown in outline only f or clarity; and Figure 6 is a part sectional top view of the apparatus of Figures 2 and 4, with some parts shown in outline only f or clarity.

1% With reference to Figures 1, 3 and 5 of the drawings, apparatus for independently adjusting both the inclination and the height of a seat frame 6 of a chair in response to movement of a single lever 11 is mainly disposed within a housing 1. The housing 1 is supported on a castor base 23 by a fluid cylinder 17 and its associated piston rod 27. The seat frame 6 is pivotally mounted at 52 to the housing 1, and is also connected to the housing 1 by a fluid cylinder 8 and its associated piston rod 28. In particular, one end of the fluid cylinder 8 is connected to the seat frame 6 by a pivotal mounting 7, and the piston rod 28 which extends from the other end of the fluid cylinder 8 is rotatably mounted by a pin 9 to a support 37 fixed on the housing 1. Each of the fluid cylinders 8 and 17 is provided with a valve (not shown). These valves are of a type which when actuated allow the piston rod 28,27 to move into and out of the fluid cylinder 8, 17 respectively but when not actuated hold the piston rod 28,27 fixed relative to the fluid cylinder 8, 17. The valves of the f luid cylinders 8 and 17 are actuated by depression of valve actuators 20 and 19 respectively.

Details of the pivotal mounting at 52 of the seat frame 6 to the housing 1 are best seen in Figure 5. The seat frame 6 is fixed to sleeves 43 which are free to rotate on tubular steel shafts 44 f ixed to the housing 1. The shafts 44 act as extensions to a nylon shaft 45, the ends of which are received in bores of the shafts 44. A torsion spring 42 is coiled around the nylon shaft 45 and biases the seat frame anti-clockwise (as shown in Figure 1). The ends 48 of the torsion spring 42 are anchored to a rod 46, so that the spring tension can be adjusted by movement of the rod 46 which occurs in response to rotation of a wheel 47.

1W The lever 11 is mounted on a shaft 13. Spaced from the shaft 13 but fixed to it, there is a cam pin 16 which engages in a cam track 25 in an enlarged end 15 of a cranked rod 14. The cranked rod 14 is pivotally mounted, intermediate its ends, at 34 to a support 33 f ixed on the housing 1. The free end of the cranked rod 14 is engaged in a recess 24 in a slider 18 fitted over the end of the fluid cylinder 17. The slider IS is connected to the valve actuator 19.

The lever 11 is shown in Figure 3 in a neutral position in which neither of the valves of the f luid cylinders 8 and 17 is actuated. Since the valves are not actuated the piston rods 28 and 27 are fixed relative to the fluid cylinders 8 and 17, and the inclination and height of the seat frame 6 are fixed.

If the lever is moved anti-clockwise (as seen in Figure 3), the rod 14 will pivot clockwise about its mounting at 34. This will move the slider 18 down (as shown in Figure 3), depressing the valve actuator 19 and opening the valve associated with it, thereby allowing the piston rod 27 to move into or out of the fluid cylinder, whereby the seat height is adjusted. At the same time the rod 14 is moved away from the valve actuator 20, so that the associated valve remains shut, the piston rod 28 remains fixed relative to the fluid cylinder 8 and the seat inclination is unchanged.

Conversely, if the lever is moved clockwise (as seen in Figure 3), the rod 14 will pivot anti-clockwise about its mounting at 34. This brings it into engagement with the valve actuator 20, depressing it and opening the associated valve. The piston rod is then f ree to move into or out of the f luid cylinder 8, according to whether pressure exerted by the user on the seat frame 6 is sufficient to overcome the bias of the spring 42. By this means the seat inclination is adjusted. At the same time, the end of the cranked rod 14 engaged in the slider 18 causes the latter to rise. This movement does not depress the valve actuator 19, so the piston rod 27 remains fixed relative to the fluid actuator 17 and the height of the seat is unchanged.

The aforegoing description, made with reference to the embodiment of the invention shown in Figures 1, 3 and 5, applies equally to the embodiment shown in Figures 2, 4 and 6. A fuller description may be found in our British Patent Specification No. 2252904.

Claims

1. A chair comprising a seat frame and a backrest frame, each mounted on a housing which containsmeans including a f irst f luid cylinder f or adjusting the height of the seat frame and for maintaining a selected height thereof, means including a second f luid cylinder for adjusting the inclination of the seat frame and for maintaining a selected inclination thereof, means including a third f luid cylinder for adjusting the rake of the back rest frame and for maintaining a selected rake thereof, a f irst member moveable to operate one of the first, second and third fluid cylinders, and a second member moveable to operate, independently of each other, the other two of the f irst, second and third fluid cylinders.

2. A chair according to claim 1, wherein the first member is moveable to operate the third fluid cylinder.

3. A chair according to claim 1 or claim 2, wherein the f irst and second members are controlled by f irst and second handles respectively.

4. A chair according to any preceding claim, wherein movement of the second member in a f irst direction operates one of the first, second and third fluid cylinders and movement of the second member in a second direction operates another of the first, second and third cylinders.

5. A chair according to any preceding claim, wherein the second member is a pivotally mounted cranked rod.

6. A chair according to any preceding claim, wherein the seat frame is pivotally mounted on the housing and biassed to- move in one direction about the axis of the pivotal mounting.

7. A chair according to claim 6, wherein the bias is provided by one or more springs coiled around a shaft in the housing on which the seat frame is pivotally mounted.

IL A chair according to claim 6 or claim 7, in which the bias is adjustable.

9. A chair according to claim 7 and claim 8 in which the bias is adjustable by moving the anchoring point of the or each spring in response to rotation of a wheel on the housing.

10. A chair comprising a seat frame and a backrest frame, each mounted on a housing which contains means including a first fluid cylinder for adjusting the height of the seat frame and for maintaining a selected height thereof, means including a second fluid cylinder for adjusting the inclination of the seat frame and for maintaining a selected inclination thereof, and a member moveable to operate, independently of each other, the first and second fluid cylinders, the backrest frame being pivotally connected to the housing and connected to and spaced from the seat frame by a link hinged at both ends.

11. A chair substantially as described herein with reference to Figures 1, 3 and 5 of the drawings.

12. A chair substantially as described herein with reference to Figures 2, 4 and 6 of the drawings.