The present invention relates to a device for a wheel chair, comprising a base frame,

- a seat, which can be tilted to different angles

relative to the base frame,

- a backrest, which can be tilted to different angles relative to both the base frame and the seat, and

- an arm support member.

WO 2009/058077 discloses a chair having a seat, a backrest and an arm rest, wherein the chair can assume a lying position, a sitting position and a standing position. The arm rest is pivotally fitted to the backrest via a pivotal joint and wherein the pivotal joint, in its turn, is displaceable in the longitudinal direction of the backrest via a rail system on the backrest. A rather complicated linkage, comprising the above-mentioned rail system, ensures that the arm rest is horizontal in all positions of the chair.

A disadvantage with this chair is that it becomes rather complicated and heavy, since it requires that a rail system is disposed in the backrest. Furthermore, it is not comfortable for the user that the arm rest moves relative to the backrest, because this may cause friction between forearms and arm support and/or between back and backrest. Furthermore, the backrest is pivoted directly via a link to the seat, which results in a movement of the backrest that does not follow the natural pattern of movement of the body, for example when rising from a lying position to a sitting

position . The object of the present invention is to produce a device for a wheel chair, wherein the device comprises a backrest, a seat, and an arm support member, which is pivotally fitted to the backrest, and wherein the arm support member maintains a constant directional

orientation, which is independent of the respective tilt angles of the backrest and the seat.

The device according to the invention comprises an arm linkage, doing away with the disadvantages of the prior art described above . The device according to the invention is characterized in that the arm support member comprises an arm support portion, a guiding portion, and a central portion, which is located between the arm support portion and the guiding portion, wherein the arm support member has its central portion pivotally fitted to the backrest via a first pivot point, furthermore the device

comprises an arm linkage, articulately connecting the arm support member to the base frame, said arm linkage comprising :

- an elongated, upper link arm, which is pivotally fitted to the guiding portion of the arm support member via a second pivot point;

- an elongated, lower link arm, which, on the one hand, is pivotally fitted to the upper link arm via a third pivot point and, on the other hand, is pivotally fitted to the base frame via a fourth pivot point; and

- a body, which is movably disposed for moving along the upper link arm and the lower link arm, wherein the seat is pivotally fitted to this body via a fifth pivot point, wherein the configuration of the arm linkage ensures that the arm support member maintains a constant directional orientation, which is

independent of the respective tilt angles of the backrest and the seat. In the following, the invention will be described more closely with reference to accompanying drawings .

Figure 1 shows a first preferred embodiment of a device according to the invention, where the device is in a lying position.

Figure 2 shows the device of Figure 1, where the device is in a sitting position.

Figure 3 shows the device of Figure 1, where the device is in a standing position.

In the following, the word end portion will be used on several occasions. As used herein, end portion refers to a portion of a body or an object. In particular, end portion will be used for describing two bodies which are pivotally fitted to each other via a common pivot point, wherein the end portion of the first body is pivotally fitted to the end portion of the second body via the common pivot point. It will be appreciated by a skilled person that the position of the pivot point of the respective body does not necessarily have to be located close to the end, although this is preferred. The pivot point of the respective body can be positioned at a predetermined distance from the end inward toward the centre of the body, where a pivoting movement between the first and the second body is enabled such that the function of the invention is achieved. Accordingly, the end portion of the respective body is a portion extending from one end of the body and inward toward the centre of the body, where the above-mentioned pivot point can be located, which enables the function of the invention to be achieved.

The device described in the following is intended to be used in a wheel chair for a user with reduced mobility. The device comprises a uniform base frame 1 having a forward end portion 18 and a rearward end portion 19; a seat 2 having a free, forward end portion 20 and an articulated, rearward end portion 21, said seat 2 being articulately connected to the base frame 1 via a seat linkage such that the seat 2 can be tilted relative to the base frame 1 via the seat linkage; a backrest 3, which is articulately connected to the seat 2 via a back linkage such that the backrest 3 can be tilted relative to both the base frame 1 and the seat 2 via the back linkage; a V-shaped arm support member 4, which is pivotally fitted to the backrest 3 via a first pivot point A and an arm linkage 5, articulately connecting the arm support member 4 to the base frame 1 such that the arm support member 4 maintains a constant directional orientation, which is independent of the tilt of the backrest 3 and the tilt of the seat 2. The seat 2, the backrest 3 and the arm support member 4 are all so disposed that their relative movements take place along a vertical plane in the longitudinal

direction of the base frame 1. The arm linkage 5 comprises an elongated, upper link arm 6 having an upper, first end portion 7 and a lower, second end portion 8; an elongated, lower link arm 9 having an upper, first end portion 10 and a lower, second end portion 11, and a displaceable, telescopic sliding body 12 having an upper, first end portion 22 and a lower, second end portion 23, said sliding body 12 being adapted to move along the upper link arm 6 and the lower link arm 9. The arm support member 4 is intended to interact with a forearm of a user who directly or indirectly supports the forearm on the arm support member 4. The arm support member 4 comprises an arm support portion 13, a guiding portion 14, and a pointed, V-shaped central portion 17. At the arm support portion 13, the arm support member 4 comprises an upper, free, first end portion 15, and, at the guiding portion 14 , the arm support member 4 has a lower, articulated, second end portion 16. The central portion 17 is located between the arm support portion 13 and the guiding portion 14, where the arm support portion 13 meets the guiding portion 14. The central portion 17 of the arm support member 4 is pivotally fitted to the backrest 3 via a first pivot point A. The arm rest (not shown in figure) is intended to be fitted to the arm support portion 13 of the arm support member 4. The guiding portion 14 of the arm support member 4 is adapted to ensure that the arm support member 4 always has a constant direction of orientation during use. This enables both the arm support portion 13 and the arm rest to also have a constant directional orientation. The guiding portion 14 has its second end portion 16

pivotally fitted to the upper, first end portion 7 of the upper link arm 6 via a second pivot point B. A soft arm support body (not shown in figure) can be fitted to the arm support portion 13, on which arm support body the user supports his forearm. The padded arm support body can also be an integrated part of the arm support portion 13 itself.

The lower, second end portion 8 of the upper link arm 6 is pivotally fitted to the first end portion 10 of the lower link arm 9 via a third pivot point C.

The second end portion 11 of the lower link arm 9 is pivotally fitted to the base frame 1 via a fourth pivot point D, wherein the fourth pivot point D is located at the forward end portion 18 of the base frame 1. The rearward end portion 21 of the seat 2 is articulately connected to the first end portion 22 of the sliding body 12 via a fifth pivot point E. Figure 1 shows the device in a lying position, where the seat 2, the backrest 3 and the arm support portion 13 are all in a horizontal position. The first end portion 22 of the sliding body 12 is then located close to the third pivot point C, which pivotally connects the upper link arm 6 to the lower link arm 9.

Figure 2 shows the device in a sitting position, where the seat 2 and the arm support portion 13 are both horizontal and where the backrest 3 is in an upright, vertical position. The first end portion 22 of the sliding body 12 is then still located close to the third pivot point C. When raising the backrest 3, the backrest 3 is pivoted in a first pivoting direction,

simultaneously as the arm support member 4 is pivoted around the first pivot point A in a second pivoting direction, which is opposite to the first pivoting direction. The pivoting movement of the arm support member 4 results from the fact that the upper link arm 6 is pivotally fitted to the guiding arm 14 of the arm support member 4 via the second pivot point B. Raising the backrest 3 will cause the upper link arm 6 to be pivoted in the first pivoting direction around the third pivot point C. This means that the horizontal direction of orientation of the arm support portion 13 is

maintained during the entire raising movement of the backrest 3.

Figure 3 shows the device in a standing position, where the arm support portion 13 is horizontal and where both the seat 2 and the backrest 3 are vertical. The backrest 3 is now located directly above the seat 2 which, in its turn, is located above the forward end portion 18 of the base frame 1. The rearward end portion 21 of the seat 2 is now located at a position above the forward end portion 20 of the seat 2. When raising the seat 2 and the backrest 3, the first end portion of the sliding body 12 is moved over to the upper link arm 6, so that the second end portion 23 of the sliding body 12 is now located at the third pivot point C. During the raising operation, the lower link arm 9 is pivoted around the fourth pivot point D, so that the upper, first end portion 10 of the lower link arm 9 exerts a pressing force on the second end portion 8 of the upper link arm 6, said force causing the pivot point C and the upper link arm 6 to be

conjointly pivoted upwardly. This means that the arm linkage 5 will maintain constant the direction of

orientation of the arm support member 4 during the movement, which means that the direction of orientation of the arm support portion 13 will be maintained

horizontal during the entire raising movement of the seat 2 and the backrest 3.

Through the invention, it is achieved that the arm support portion 13 of the arm support member always maintains its horizontal directional orientation,

irrespective of which tilt angle the backrest 3 and the seat 2 assumes. As mentioned previously, a soft, padded arm support body can be fitted to the arm support portion 23, or the arm support body can be integrated into the arm support portion 13 itself. In the foregoing, the invention has been described based on a specific embodiment. It will be appreciated,

however, that other embodiments and variants are possible within the scope of the following claims. It is of course not necessary that the arm support member 4 has a

V-shaped design, where the central portion 17 is pointed. It will be appreciated by a skilled person that also other, not shown designs of the arm support member 4 are possible. It will also be appreciated that the

directional orientation of the arm support portion 13 is not necessarily horizontal, but several other constant directional orientations are possible. It will also be appreciated that the arm support body can be fitted directly to the arm support portion 13 or that the arm rest can be integrated into the arm support portion 13. The essential part of the invention is that the

configuration of the arm linkage enables the arm support member to maintain its directional orientation for interaction with a forearm, and that this directional orientation is independent of the respective tilt angles of the backrest and the seat.