The prior art includes a chair of the aforementioned type, known by the name of"Tripp- trapp0", cf. Norwegian Patent 132 782. This known chair was an outstanding innovation in the field when it was marketed for the first time in about 1975. One of the disadvantages of this chair is, however, that adjustment of the seat board and the footrest board both with respect to depth and height necessitate the use of an Allen key to allow the release of the engagement between horizontal grooves in the side members of the chair and the seat and footrest boards in order to be able to move the boards into the desired position.

Similarly, EP-0689787-A1 makes known a height-adjustable chair where between the side members of the chair a plurality of bars extend in the vertical direction, and where the chair seat and footboard can be hooked onto a respective bar.

In particular when used in surroundings where the constant readjustment of such a chair is necessary, such as in kindergartens, restaurants and other eating places, or where a chair of this kind is used in the course of one day by several different people of dissimilar body length, said readjustability using a tool is laborious.

The object of the present invention is thus to provide improvements to a chair of the aforementioned type where readjustability has been made extremely simple.

According to the invention, the arrangement is characterised in that each of the boards in its depth direction is slidably and fixably attached to a respective board support, the board support for height adjustment at a forward portion being equipped with laterally and oppositely directed supporting projections for engagement with notches in guide tracks which extend up along the inside of the side members, and wherein the board support at a rear portion is designed for releasable and height-adjustable engagement with an upright, rack-like member arranged behind the chair back. According to one embodiment of the device, a clamping means, e. g., an eccentric clamp, is connected to the rear portion of the board support, wherein by operating the clamping means said

supporting projections are held in engagement with respective adjacent notches in the side members and said rear portion engages with an adjacent notch in said rack-like member.

The invention will now be described in more detail with reference to the exemplary embodiments illustrated in the appended drawings.

Fig. 1 shows the arrangement according to the invention seen in perspective from in front and from below.

Fig. 2 shows the arrangement according to the invention seen in perspective from behind and from above.

Fig. 3 shows the arrangement seen in perspective from in front and from above.

Fig. 4 shows a section and a cross-section through the arrangement according to the invention.

Fig. 5 shows the adjustable chair arrangement seen straight on from one side.

Fig. 6 shows a section of the arrangement according to the invention seen from the underside of the adjustable chair and in perspective from in front.

In the drawings the chair is indicated by means of the reference numeral 1. The chair has two side members 2,3, rungs 4,5 which connect the side members at the bottom, and wherein the rungs are secured by means of screws or bolts 7,8,7', 8'. as indicated in particular on Figs. 1,2 and 3.

At the top, the chair has an upper chair back part 6 and a lower chair back part 10. The chair back parts 6,10 are secured to the side members by means of screws 9,10'. The chair back part 10 is in reality retained only by the clamping action obtained by the engagement of the screws 9,9'with the chair back part 6 through respective side members 3,2. The chair back part 10 is preferably equipped at its respective ends with dowels (not shown) which engage with the side members 2,3.

The chair has a height-and depth-adjustable seat board 11 and a height-and depth- adjustable footrest board 12. The seat board 11 is in its depth direction slidably and

fixably attached to a first board support 13. Similarly, the footrest board 12 is slidably and fixably attached to a second board support 14. As can be seen from Fig. 4 and in part also from Fig. 6, the fixable depth adjustability is operated by adjusting screws 15, 16 for the boards 11 and 12 respectively. The board support 13 has at its forward portion a crosspiece 21 which is equipped with laterally and oppositely directed supporting projections 23 for engagement with notches 20 in guide tracks 19, which extend up along the inside of the side members 2,3. Similarly, the board support 14 for the footrest board 12 has at a forward portion a crosspiece 22 equipped with laterally and oppositely directed supporting projections 24 which likewise are designed for engagement with said notches 20 in the guide track 19.

The board supports 13 and 14 respectively are at a rear portion 13' ; 14'designed for releasable and height-adjustable engagement with an upright, rack-like member 25 which is arranged behind the chair back 6,10. The rack-like member 25 at the lower end thereof is preferably recessed into or attached in some other manner to the transverse rung 5 and at the upper end thereof is connected by means of an attachment bar 26 to the rear of the chair back, e. g., to the chair back part 10.

The arrangement includes clamping means 30, 31, e. g., eccentric clamps, which via respective attachment pieces 28 and 29 are connected to the board supports 13; 14 via a slot 25'in the rack-like member 25. The rack-like member 25 is provided with transverse notches 27 into which the said rear portions 13', 14'of respective board supports 13,14 will fit.

When the clamping means 30,31 are made to form clamping abutment against the back of the rack-like member 25, as can be seen most easily from Fig. 4, the supporting projections 23,24 will be drawn into respective notches 20 in the side members 2,3 at the same time as the rear portion 13', 14'of the support 13,14 engages with an adjacent notch 18 in the side member 2 and 19 in the side member 3.

Modifications of the arrangement described and illustrated herein are conceivable within the scope of the invention as defined in the patent claims below.