The present invention concerns a divided chair seat where the parts of the seat can be shifted independently of each other in a plane. The chair seat is particularly adapted for surgeons who in many cases must sit and work for several hours in a confined space with considerable precision. The chair seat is designed to be adaptable for many users with dissimilar anatomy and various forms of work.

The chair seat can be adapted for many sitting positions, including partly standing positions, a backward position on the chair with a back supporting the stomach or chest, and an ordinary sitting position.

An example of a chair for surgeons is shown in US-A-5029941 showing a number of support functions and adjustment possibilities, but not a seat as defined in the present claim set.

An example of a three part seat is shown in NO-B-178483 describing a driver's chair for boats, where a boatman can have an ordinary sitting position, or a somewhat more standing position when the sides of the seat are hinged down and the seat is shaped as a saddle. The threeparted seat includes a fixed mid-section, and two side sections hinged in the mid-section, and that accordingly can be folded down.

Yet another example of a three part seat is shown in NO-B-180221 showing a seat with hinged front parts making it possible for a user to change sitting position by changing the hip angle.

Accordingly it has not been shown a chair seat with a parted sitting face where the separate parts can be shifted in relation to one another in a plane, substantially parallel to the sitting face of the seat as defined in the present claims. The chair seat includes three or more moving seat parts therebetween, shiftable or extendable in substantially one single plane. The seat may furthermore include a transversal frame, and the various parts of the chair seat may be fixed to the transversal frame via the gliding faces. The transversal frame can be adapted to be secured in a chair cylinder.

The seat includes at least a right seat part, a centre seat part and a left seat part.

The shiftable parts of the seat can be locked to the transversal frame with the locking mechanisms.

The chair seat may be particularly adapted for a chair for surgeons. The chair seat may, however, also be well suited for others, for instance dentists, goldsmiths, boat drivers and other professions where greater flexibility in terms of sitting position may be advantageous.

Short description of the enclosed drawings:

• Fig. 1 is a perspective view of an embodiment of a chair with a seat according to the invention;
• Fig. 2 is a perspective view of an embodiment of a seat according to the invention, where the parts of the seat are in a first position;
• Fig. 3 is perspective view of the embodiment of the seat shown on Fig. 2 where the parts of the seat are in a second position;
• Fig. 4 is a perspective view of the embodiment of the seat shown on Fig. 2 where the parts of the seat are in a third position; and
• Fig. 5 is a perspective view of the seat shown on Figs. 1 and 2 seen from below, and where the parts of the seat are in a fourth position.

Detailed description of the present invention.

From Fig. 1 it is shown a chair 10 with a undercarriage 12, a chair back 13 and a seat 11 according to the invention. From the figure it is shown a centre seat part 5 with a saddle shape in an extended position such that the chair seat 11 is in a configuration that is adapted for a partly standing position. Furthermore, it is shown how the left seat part 6 and the right seat part 1 are designed with a shape adapted to the centre seat part 5 where the faces of the seat parts face each other. A chair cylinder 4 with a height adjustment is shown between the chair seat 11 and the undercarriage 12.

From Fig. 2 it is shown a chair seat according to the invention, where a right seat part 1, a centre seat part 5 and a left seat part 6 are mounted to a transversal frame 3. The transversal frame may be secured to a chair cylinder 4. The chair cylinder 4 may be connected to an ordinary chair undercarriage in a way otherwise well known within the field as shown on Fig. 1.

The seat parts can be adjusted in the longitudinal direction on the transversal frame 3 through gliding faces 2. The centre seat part 5 may have sides formed as a bow, such that when the centre part 3 is led forward, and/or when the right seat part 1 and the left seat part 6 are led backwards, the centre seat part 5 will form the shape resembling a saddle shown on the other figures. Also in the this figure it is shown how the right seat part 1 and the left seat part 6 are shaped with a shape adapted to the saddle shape of the mid-part, such that it is not created substantial recesses in the seat when the seat is placed in an initial position where the three seat parts are placed side by side without being shifted or extended in relation to each other.

From Fig. 3 it is shown the seat of Figs. 1 and 2, but where the right seat part 1 is retracted somewhat in relation to the transversal frame 3 along the right gliding face 2. The rounded sides of the centre seat part are clearly shown. The left seat part 6 is shifted backwards, considerably further than the right seat part 1. From the figure it is shown how the right seat part 1, the centre seat part 5 and the left seat part 6 can be shifted in a plane, independently of each other.

From Fig. 4 the seat from Figs. 1, 2 and 3 is shown, but where the right seat part 1 is extended forward in relation to the transversal frame 3 along the right gliding face 2. The left seat part 6 is shifted backwards. Also from Fig. 4 it is shown how the right seat part 1, the centre seat part 5 and the left seat part 6 can be shifted in a plane, independently of each other.

In Fig. 5 the underside of the seat is shown, where the right seat part 1, is attached to the transversal frame 3 by the right gliding face 2. The centre seat part 5 is secured to the transversal frame 3 with the centre gliding faces 9. The left seat part 6 is attached to the transversal frame 3 by the left gliding face 7. The gliding faces 2, 7 and 9 can be guiding rails, well known within the field, and can be of any suitable type. Locking handles 8 are shown placed behind the centre seat part 5. Locking handles 8 are provided to be able to lock the seat parts 1, 5, 6 in their desired positions. Right and left seat parts 1, 6 can be connected such that these can be led back and forth with only one handle.

The locking mechanism that is controlled by the locking handles 8 may be of any kind, for instance based on lugs going into recesses in the respective elements, or be an infinitely variable friction mechanism.

The locking handles 8 are preferably placed at the back of the chair seat, such that these can be operated by assisting personnel, such that a surgeon does not have to touch these. This is to maintain the hands of the surgeon sterile.

Transversal seat frame 3 can be a simple plate with the gliding faces, guides or rails 2, 7, 9 fixed thereto. Alternatively, the seat frame 3 can be a suitable frame, fixture or some other suitable contraption for fixing the gliding faces 2,7,9.

The shown chair 10 is both suitable as an office chair and as a chair that is suitable for a high sitting position or as a standing chair. In neurological operations the surgeon may prefer a tall sitting position for some operations and a lower position for other operations. To sit comfortably in partly standing tall positions the seat should have less support for the thighs, for example a saddle shape, whereas for low and more normal sitting positions it is common to need more support for the thighs. The shown seat can be adjusted and transformed such that the sitting face is optimised for all sitting positions.

The adjustment of the sitting face can in alternative embodiments be performed electromechanically, electronically, pneumatically, hydraulically or in a combination of these.

The chair seat is preferably intended used in connection with a chair with a chair back and an undercarriage, well known within the field.

The chair is adapted for various sitting positions, and accordingly the chair undercarriage will normally be of a type with adjustable height.

The chair seat is shown parted in three parts, but the seat may be made with several seat parts, for instance four or five. The embodiment shown on the figures with three parts is chosen because the balance of the chair easily can be accommodated for, and at the same time full flexibility is maintained.