Chair incorporating a control arrangement

Abstract: A control arrangement for a chair (1) comprises two gas springs (25, 37) each for individually operating one chair adjustment function, each gas spring being remotely operated by means of its own cable (53, 65). The invention also includes a chair incorporating this control arrangement.

Description: This invention relates to a control arrangement for a chair and to a chair incorporating such a control arrangement. It is suitable for use in an office type chair but may also be used on any type of adjustable chair. In most chair adjusters, parts of the chair are adjusted relative to each other. This may include the adjustment of the angular position of the chair in relation to its support, the so called "rocking" adjustment, the adjustment of the height of the chair relative to is support and relative movements between chair parts, typically adjustments between the seat itself and the chair back. Usually the adjustment is organised such that the chair is biased into one extreme position and can be moved against the bias to a desired position and locked there. Once the adjustment has been unlocked, the chair will revert to its extreme position and can then again be readjusted and locked in the new position. Up to the present time, most such a mechanisms have been a combination of a spring and a mechanical clutch, the spring acting as the biasing means and the clutch acting as the necessary locking means. This has two main disadvantages. Firstly, the strength of clutch necessary to hold the adjustment has often to be such that it is difficult for the operator to operate the clutch. Secondly, there is the problem that when the clutch is released, the chair moves extremely fast under the action of its spring and can cause discomfort or even damage to the operator. Proposals have been made to use gas springs for certain chair adjustments. Previous uses of gas springs have resulted in an extremely complicated arrangement having a single control operating two gas springs or the use of a single gas spring to provide a semi-automatic arrangement brought about by movement of the chair's user. Locking or unlocking of the device is carried out by means of a cable control. The present invention seeks to provide a simple control arrangement for a chair using gas springs, such as disclosed in DE 36 17 539 C. According to the invention, there is provided a chair comprising a stand, a vertical pillar carried by the stand and comprising a first gas spring mounted in the vertical pillar for controlling the seat height of the chair, a seat support structure carried by the piston of the gas spring and extending radially therefrom, a seat carrier pivoted horizontally to the seat support structure and extending backwards to overlie the first gas spring, a second gas spring pivotally connected between a region of the seat support structure intermediate the first gas spring and the pivot with the seat carrier and the seat carrier for controlling the seat angle of the chair, a seat mounted on the seat carrier, a seat back pivotally mounted towards the end of the seat carrier away from its pivotal connection with the seat support structure, a third gas spring pivotally connected between the seat back and the seat carrier for controlling the back angle of the chair, three cables, each connected to a gas spring to operate the gas spring remotely and three Individual and separate actuators, each actuator controlling one cable. The chair may further comprise a control console located adjacent to the seat and having three controls, each individually connected to a gas spring. Each control may be connected to the respective gas spring by means of a Bowden cable and may be in the form of a lever. The invention will now be described in greater detail, by way of example, with reference to the drawings, in which:- Figure 1 is perspective view of a chair in accordance with the invention: Figure 2 is a side view of the chair of figure 1, and Figure 3 is an enlarged view of the arrangement and connection of the gas springs. Referring firstly to figure 1, there is shown an office type chair 1 comprising a stand 3 having four legs 5. In some circumstances, five legs could be used. Usually the feet ends 7 are provided with castors such as shown at 9 in figure 2. The stand 3 carries a pillar 11 which is of a telescopic nature, and in the present invention is formed by a gas spring. The inside telescopic member or the piston rod of the gas spring carries a seat supporting system 13 which in turn carries the seat 15. Also carried by the seat supporting system is a back 17. The back 17, in the chair shown, has an internal back adjuster controlled by a knob 19 which, however, forms no part of the present invention and will not be further described. A control console 21 has three control levers 23 which control the three major chair adjusting functions, namely:- 1. Seat height 2. Seat angle. 3. Back angle Figure 2 shows more detail of the chair adjustment arrangements, fuller detail being shown in figure 3. As can be seen from figure 2, the pillar 11 is a gas spring 25 having its cylinder part 27 mounted on the stand 3 and to the top of the piston rod 29 is mounted a seat support structure 31 which extends radially therefrom and at an upward inclination. A seat carrier 33 is pivoted horizontally at 35 to the seat support structure 31 and extends backwards to overlie the gas cylinder 25. A second gas spring 37 is pivotally connected between a region of the seat support structure 31 intermediate the first gas spring 25 and the pivot 35 with the seat carrier 33, The seat carrier 33 carries the seat. The seat carrier 33 also carries the seat back 17 which is mounted on an arm 41 pivotally mounted at 43 towards the end of the seat carrier 33 away from its pivotal connection 35 with the seat support structure 31. A third gas spring 45 pivotally connected between the seat back mounting arm 41 and the seat carrier 33. Referring now to figure 3, the various parts of the control arrangements are shown. Firstly, it will be noted that pivot 35 between the seat support structure 31 and the seat carrier 33 has a spring which urges the seat carrier 33 to an adjustable end position of pivotal movement. Adjustment is carried out by the mechanical screw arrangement shown at 49. The first gas spring 25 is controlled through its piston 29 by a lever 51 operated by a Bowden cable 53 connected to a first of the control levers 23 on the console 21 (Figure 1). Mounting of the seat support structure 31 on the piston 29 is shown at 55. The second gas spring 37 is pivotally mounted by its piston rod end 57 to the seat support structure 31 at 59 and is pivotally mounted by its cylinder 61 to the seat carrier 33 at 63. Its operation is controlled by a second control lever 23 (figure 1) through a Bowden cable 65. The seat carrier 33 has a depending section 67 which carries are end of the third gas spring 45. Thus, the third gas spring 45 is pivotally connected by its piston rod 69 to this depending section 67 at 71. The cylinder 73 of the third gas spring 45 is pivotally connected to the seat back mounting arm 41 at 75. Control of this third gas spring is through a Bowden cable 77 from the third control lever 23 (figure 1). The operation of the chair adjustments will now be considered:- 1. Seat Height This adjustment is carried out by the first gas spring 25. When its control lever 23 is raised, the gas spring 25 is unlocked and allows the seat to be raised under the action of the gas spring. Adjustment of the height is brought about against the action of the gas spring 25. Once the desired position has been reached, the lever 23 is allowed to return downwards, locking the gas spring so that the selected height is retained. 2. Seat Angle This adjustment is carried out by the second gas spring 37 in combination with the pivot spring 47 and its tension adjuster 49 which provides a counterbalance for the body weight of the user. To actuate this mechanism, the second lever 23 is raised to unlock the gas spring 37. In the upper position of this lever 23, a ratchet (not shown) retains it in this position. This allows the seat carrier 33 and the seat 15 to pivot about the pivot 35, together with the seat back 17. Lifting of the lever 23 again releases the ratchet and allows the lever to drop back to its lower position, locking the gas spring 37 and the seat carrier 33 at the selected angle. 3. Back Angle This adjustment is carried out by the third gas spring 45. Raising of the appropriate lever 23 unlocks the gas spring 45 and allows the seat back to be adjusted against the action of the spring. Once the selected angle has been reached, the lever 23 is released to lock the gas spring and thus the back 17 in the selected position. The advantages of the above described embodiment are the independent control over the seat height, seat angle and back angle by control levers dedicated to each movement. The cable control system allows optimum placement of the control lever and this ease of adjustment improves the chair functions. The ease of adjustment allows the user to make intuitive adjustments to the seat and back position thereby increasing the degree of comfort while seated. It will be appreciated that additions to or modifications of the above described invention are possible. For example, while all three functions have been described using gas springs, one of these could be replaced by a mechanical arrangement where location of the controls permits. A seat sliding mechanism could be incorporated to enable the seat 15 to be slid backwards and forwards in relation to the back 17. This slide arrangement would be located between the seat 15 and the seat carrier 33 and could be locked and unlocked by the operation of a further lever using a gas spring, if desired. This lever could be located as an additional lever on the console 21 or in any other convenient position. Operation of this mechanism by means of a Bowden cable could be advantageous. The lever mechanisms 23 could be replaced by a push button type control. The integrated control of the gas springs is not essential. Instead, a standard gas spring could be used and an actuator provided on the end of the Bowden cable to actuate the usual actuating mechanism While the gas spring 45 has been shown having its own support arrangement 67, this could be incorporated in the general mechanism indicated generally in figure 1 by the reference 13. Furthermore, it is not necessary for the controls all to be located in a single console. The controls could be individually placed wherever desired.

Claims: A chair (1) comprising a stand (3), a vertical pillar (11) carried by the stand (3) and comprising a first gas spring (25) mounted in the vertical pillar (11), for controlling the seat height of the chair (1),a seat support structure (31) carried by the piston (29) of the gas spring (25) and extending radially therefrom, a seat carrier (33) pivoted horizontally to the seat support structure (31) and extending backwards to overlie the first gas spring (25), a second gas spring (37) pivotally connected between a region of the seat support structure (31) intermediate the first gas spring (25) and the pivot (35) with the seat carrier (33) and the seat carrier (33) for controlling the seat angle of the chair (1), a seat (15) mounted on the seat carrier (33), a seat back (17) pivotally mounted towards the end of the seat carrier (33) away from its pivotal connection with the seat support structure (31), and a third gas spring (45) pivotally connected between the seat back (17) and the seat carrier (33) for controlling the back angle of the chair (1), characterized in that the chair (1) further comprises three cables (53, 65,77), each connected to a gas spring (25, 37, 45) to operate the gas spring (25, 37, 45) remotely and three individual and separate actuators (23), each actuator controlling one cable (53, 65, 77). A chair (1) as claimed in Claim 1 further comprising a control console (21) located adjacent to the seat (15) and having three controls (23), each individually connected to a gas spring (25, 37, 45). A chair (1) as claimed in Claim 1 or 2, wherein the cables (53, 65, 77) are Bowden cables. A chair (1) as claimed in Claim 2 or 3, wherein the controls (23) are in the form of levers.

Inventors: GLASER ALAN, GLASER LESLEY, GLASER, ALAN, GLASER, LESLEY
Applicants: GLASER ALAN, GLASER LESLEY, GLASER, ALAN, GLASER, LESLEY
Application year: 2001
Main classification: A47C1
IPC codes: A47C3, A47C1