The present invention relates to an arrangement in chairs of the kind having a central pillar carrying a seat provided with a back support, and coacting with a base structure including at least three feet consisting of supporting members integral with, and projecting transversely from, a central sleeve accommodating the pillar, the free end portions of the members project a given distance from the sleeve, and have fixings for wheels or carrying means bearing against a floor or other substructure.

Tnere iε usually a problem with this kind of chairs, particularly v en the back support is provided with a neck rest, the problem being a greatly increased risk o ^" the chair ripping over if tne standard case struct¬ ure is used.

Th3 object of the invention is to achieve a^ extension of the feet included in the base of the chair in ques¬ tion, such that the tipping hazard and possible injury to the user as a result of tipping are to a large extent eliminated. The distinguishing features of the invention are disclosed in the accompanying claims.

As a result of the invention, there has nov been achieved an arrangement in the base structure of a chair, where this arrangement excellently fulfils the objectives set for it, while being both sir.ple and cheap in manufacture. With the aid of the arrangement, which takes the form of an inventive extension piece for each foot, the wheels, or other carrying means v/hich may have been originally fitted to the feet, may be transferred to the extension pieces. These may be already fitted on delivery, if the chair has a back support provided with a neck rest, and if the latter iε

CORRECTED

removed the extension pieces may also be removed, thus returning the chair to its standard condition without having tampered with its base structure. This is poss¬ ible, since the inventive extension piece is fixed to the respective chair foot without any damage to the foot.

The invention will now be described in more detail with the aid of a preferred embodiment example and with reference to the accompanying drawings, where

Fig. 1 is a side view of a foot in the base structure of a chair of the kind mentioned in the intro¬ duction, the foot being provided with means in the form of a castor wheel for bearing against the floor.

Fig. 2 is a view from above of the foot illustrated in Fig. 1,

Fig. 3 is a partial side view along the line III-III in Fig. 2, and

Fig. 4 is a cross-section through the extension piece along the line IV-IV in Fig. 1.

As will be seen from the figures, particularly Fig. 1, the base structure 1 of a chair includes a foot 2, of which there are at least three. Each foot 2 consists of a supporting member 5 fixed to, and transverse the longitudinal direction of a central sleeve 3 accommo¬ dating a pillar 4, for carrying an unillustrated chair seat. The members 5 project a given distance from the sleeve 3, and at their free ends 6 there are fastening means 7 for carrying means, in this case castor wheels 10. In accordance with the invention, at least one, preferably two, extension pieces 8 are fitted to feet 2

when the chair has been provided with a neck rest. The illustrated extension piece 8 is accordingly removably attachable to fastening means 7 of the member 5, in¬ stead of the wheels or carrying means 10, thus achiev- ing greater spread of said means 10, which results in greater stability for the chair in question, when it has been provided with an accessory such as a neck rest. In the illustrated example, the extension piece 8 has at its outer, free end 11 a fastening means 9, which is substantially the same as the fastening means 7. Consequently, the same wheel 10 can be mounted on the extension piece 8 as was mounted on the fastening means 7 on the supporting member 5.

The inventive extension piece 8 has an angularly bent fastening plate 20 at its removably attachable portion 12 at the free end portion 6 of the supporting member 5. With the aid of the fastening plate 20, when the plate is made integral with the clamping plate 16 in a bolted joint 13, the extension piece 8 may be fixably clamped at the free end portion 6 of the supporting member 5, and may also take up an angular deviation in relation to the longitudinal direction of the support¬ ing member 5, this deviation being preferably between 30° and 45°. By this deviation, further stability of the chair may be obtained.

In the preferred embodiment example the extension piece 8 comprises a tubular section 14, corresponding in cross-section to the tubular section 15 forming the supporting member 5. In addition, the tubular section 14 has a length in the illustrated embodiment example that substantially corresponds to 1/3-1/5 of the tubu¬ lar section 15. The bolted joint 13, used for attaching the extension piece to the foot 2 of the base structure 1, comprises two opposing clamping plates 16 and 17, which are intended to be placed on either side of the

tubular section 15, and clamped together with the aid of bolts 18, 19 and associated nuts and washers. To make the attachment of the extension piece 8 to the foot 2 as stable as possible, the plate 20 is also provided with a reinforcing plate 21, fixed under, and at right angles to it. This plate 21 projects out a short distance at the attachment end of the tubular section 14, and has a hole 23 in the projecting portion 22. Through this hole a bolt 24 is intended to extend and fix the plate 21 in the fastening means 7 of the supporting members 5.