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

- a base frame,

- a plane, onto which a wheel chair seat is intended to be disposed, and

- a linkage, which is disposed between the base frame and the plane, wherein the linkage is intended for supporting the plane and enabling lifting and tilting of the plane .

There are wheel chairs having seats , where the seat is adjustable vertically, for example in order to make it easier for the user to reach up to a certain height. There are also wheel chairs having seats, where the seat can be tilted forward/back, for example in order to give the user a more comfortable sitting position and/or to make it easier for the user to move from the wheel chair to a bed or a chair. Usually the wheel chairs have either a lifting function or a tilting function, since the respective function normally requires separate linkages. This means that wheel chairs having both functions tend to become expensive, heavy, large and complicated.

EP 2 050 424 Al discloses a wheel chair, comprising a seat and two lifting arms, upon which the seat is supported such that the seat can be lifted, lowered and tilted. The movement of the respective arm is produced by electric actuators, which are connected to the lifting arms via pivotal link arms. A disadvantage of this wheel chair is that the design of the linkage means that large forces from the actuators are required to produce the movements. The object of the present invention is to produce a device for a wheel chair, wherein the device comprises a linkage which eliminates the disadvantages described above. Furthermore, the linkage according to the invention makes possible lifting and tilting of a seat in a wheel chair with a relatively small, substantially horizontally directed force.

The device according to the invention is characterized in that the linkage comprises a first sub- linkage and a second sub- linkage, wherein the two sub- linkages are disposed mirror- inverted to each other and wherein the respective sub-linkage comprises:

- an actuator, comprising a first end portion and a second end portion, wherein the first end portion is pivotally fitted to the base frame;

- a V-shaped pivotal lifting arm, comprising a first leg, a second leg and a central portion, wherein the first leg is pivotally fitted to the second end portion of the actuator and wherein the central portion of the pivotal lifting arm is pivotally fitted to the base frame;

- a link arm, comprising a lower, first end portion and an upper, second end portion, wherein the first end portion is pivotally fitted to the second leg of the pivotal lifting arm;

- a lower lifting arm, comprising a lower, first end portion and an upper, second end portion, wherein the first end portion is pivotally fitted to the base frame and wherein the second end portion of the link arm is pivotally fitted to the lower lifting arm;

- a steering arm, comprising a lower, first end portion and an upper, second end portion, wherein the first end portion is pivotally fitted to the base frame; and - an upper lifting arm, comprising a lower, first end portion and an upper, second end portion, wherein the first end portion is pivotally fitted to the upper, second end portion of the steering arm, wherein the upper, second end portion of the lower lifting arm is pivotally fitted to the upper lifting arm, and

wherein the upper, second end portion of the upper lifting arm is pivotally fitted to the plane. 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 a plane for supporting a seat is lowered in a horizontal position.

Figure 2 shows the device of Figure 1, where the plane is in a position with a first tilt direction. Figure 3 shows the device of Figure 1, where the plane is in a position with a second tilt direction.

Figure 4 shows the device of Figure 1, wherein the plane is raised in a horizontal 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 for a wheel chair, which is intended to be used by a user with reduced mobility. The device is to support a seat (not shown) of the wheel chair, on which seat the user will sit. The device should be capable of raising and lowering the seat, and also of tilting the seat in first, backward direction and in a second, forward direction.

The device comprises a uniform base frame 1, a lifting and lowering linkage 6, 6', comprising a forward, first sub-linkage 6 and a rearward, second sub-linkage 6', wherein the respective sub-linkage 6, 6' is liftable and lowerable . The device further comprises a plane 31 for mounting a wheel chair seat thereon, wherein the plane 31 has a forward, first end portion 32 and a rearward, second end portion 33. Furthermore, the plane 31

comprises a forward, first portion 29, where the forward, first end portion 32 of the plane 31 is located, and a rearward, second portion 30, where the rearward, second end portion 33 of the plane 31 is located. The plane 31 is supported by the linkage 6, 6' such that the two sub- linkages 6 and 6' of the linkage interact with each other, which enables a lifting movement, a lowering movement and a tilting movement of the plane 31.

The base frame 1 has a first side 2 and a second side 3, which is opposite to the first side 2. The base frame 1 further has a forward, first end portion 4 at the first side 2 and a rearward, second end portion 5 at the second side 3. The first sub- linkage 6 is disposed on the first side 2 of the base frame 1 and the second sub- linkage 6' is disposed on the second side 3 of the base frame. The two sub- linkages 6 and 6' are so disposed that they are mirror- inverted to each other in relation to a plane perpendicular to the longitudinal direction of the base frame 1.

The first sub-linkage 6 and the second sub-linkage 6' each comprises a steering arm 8, 8' comprising a lower, first end portion 9, 9' and an upper, second end portion 10, 10', a V-shaped pivotal lifting arm 11, 11'

comprising a first leg 12, 12', on which first leg 12, 12' the pivotal lifting arm 11, 11' has a first end portion 13, 13', a second leg 14, 14', on which second leg 14, 14' the pivotal lifting arm 11, 11' has a second end portion 15, 15', and a V-shaped, pointed central portion 28, 28' which is located between the first leg 12, 12' and the second leg 14, 14'. The first leg 12, 12" is longer than the second leg 14, 14'. Furthermore, the respective sub- linkage 6, 6' comprises an elongated link arm 16, 16' comprising a lower, first end portion 17, 17' and an upper, second end portion 18, 18', an elongated, lower lifting arm 19, 19' comprising a lower, first end portion 20, 20' and an upper, second end portion 21, 21', an elongated, upper lifting arm 22, 22' comprising a lower, first end portion 23, 23' and an upper, second end portion 24, 24', and an actuator 25, 25' comprising a lower, first end portion 26, 26' and an upper, second end portion 27, 27'. The actuator 25, 25' is adapted to perform a linear actuating movement, so that the

respective end portions 26, 26' and 27, 27' of the actuator 25, 25' are caused to move toward or away from each other.

The lower lifting arm 19, 19' has its first end portion 20, 20' pivotally fitted to the end portion 4, 5 of the base frame 1 via a first pivot point A, A ¹ . The upper, second end portion 21, 21' of the lower lifting arm 19, 19' is pivotally fitted to the upper lifting arm 22, 22' via a second pivot point B, B' . The second pivot point B, B' is located at the upper lifting arm 22, 22' between the first end portion 23, 23' and the second end portion 24, 24', and positioned closest to the first end portion 23, 23'. The steering arm 8, 8 ¹ has its first end portion 9, 9' pivotally fitted to the base frame 1 via a third pivot point C, C . Furthermore, the second end portion 10, 10' of the steering arm 8, 8' is pivotally fitted to the lower, first end portion 23, 23' of the upper lifting arm 22, 22' via a fourth pivot point D, D ¹ .

The actuator 25, 25' has its first end portion 26, 26' pivotally fitted to the base frame 1 via a fifth pivot point E, E ¹ , and the actuator 25, 25' has its second end portion 27, 27' pivotally fitted to the first end portion 13, 13' of the pivotal lifting arm 11, 11', at the first leg 12, 12', via a sixth pivot point F, F'.

The pointed central portion 28, 28' of the pivotal lifting arm 11, 11' is pivotally fitted to the base frame 1 via a seventh pivot point G, G' . Furthermore, the pivotal lifting arm 11, 11' has its second end portion 15, 15' at its second leg 14, 14' pivotally fitted to the lower, first end portion 17, 17' of the link arm 16, 16' via an eight pivot point H, H' . The upper, second end portion 18, 18' of the link arm 16, 16' is pivotally fitted to the lower lifting arm 19, 19' via a ninth pivot point I, I' . The ninth pivot point I, I' is located at the lower lifting arm 19, 19', between the first pivot point A, A' at the first end portion 20, 20' of the lower lifting arm 19, 19' and the second pivot point B, B ¹ at the second end portion 21, 21' of the lower lifting arm 19, 19'. The upper lifting arm 22 of the first sub- linkage 6 has its upper, second end portion 24 pivotally fitted to the forward, first end portion 32 of the plane 31, at the first portion 29 of the plane 31, via a tenth pivot point J.

The upper lifting arm 22' of the second sub-linkage 6' has its upper, second end portion 24' pivotally fitted to the rearward, second end portion 33 of the plane 31, at the second portion 29 of the plane 31, via an eleventh pivot point K.

The first portion 29 and the second portion 30 are telescopically fitted to each other such that the first portion 29 is displaceable into the second portion 30.

As seen in the longitudinal direction of the base frame, the pivot points at the base frame 1 are mutually related as follows. The first pivot point A, A' is located at the end portion 4, 5 of the base frame. The fifth pivot point E, E ¹ is located close to the centre of the base frame. The third pivot point C, C is located between the first pivot point A, A' and the fifth pivot point E, E' . The seventh pivot point G, G' is located between the first pivot point A, A' and the third pivot point C, C .

Figure 1 shows the device in a position, where the plane 31 of the device is in a lowered, horizontal position, which means that both the forward, first sub- linkage 6 and the rearward, second sub- linkage 6' are lowered. The actuators 25 and 25' are retracted, so that no force acts on the link arms 16 and 16'. Here, the first portion 29 of the plane is retracted into the second portion 30 of the plane .

Figure 2 shows the device in a position, where the plane 31 of the device is tilted backward in a first direction, which means that the first sub- linkage 6 is raised and the second sub-linkage 6' is lowered. When raising the first linkage 6, the actuator 25 moves from a retracted position to an extended position, which means that the actuator 25 exerts a force on the first leg 12 of the pivotal lifting arm 11. This causes the pivotal lifting arm 11 to rotate around the seventh pivot point G, so that the second leg 14 of the pivotal lifting arm 11 exerts an upward force on the link arm 16. The link arm 16 will then exert a force on the lower lifting arm 19, which is thereby caused to rotate around the first pivot point A. The upper end portion 21 of the lower lifting arm then exerts a force on the upper lifting arm 22 at the second pivot point B. The steering arm 8 ensures that the upper, second end portion 24 of the upper lifting arm 22 is guided upward, in that the steering arm 8 keeps the lower, first end portion 23 of the upper lifting arm at the fourth pivot point D, simultaneously as the steering arm 8 rotates around the third pivot point C. During this movement, the first portion 29 of the plane will move from a retracted to a partially extended position in the second portion 30.

Figure 3 shows the device in a position, where the plane 31 of the device is tilted forward in a second direction, which means that the rearward, second sub-linkage 6' is raised and the forward, first sub-linkage 6 is lowered. When raising the second linkage 6', the actuator 25' moves from a retracted position to an extended position, which means that the actuator 25' exerts a force on the first leg 12 ' of the pivotal lifting arm 11 ' . This causes the pivotal lifting arm 11' to rotate around the seventh pivot point G ¹ , so that the second leg 14' of the pivotal lifting arm 11' exerts an upward force on the link arm 16 ¹ . The link arm 16 ¹ will then exert a force on the lower lifting arm 19', which is thereby caused to rotate around the first pivot point A' . The upper end portion 21' of the lower lifting arm then exerts a force on the upper lifting arm 22' at the second pivot point B' . The steering arm 8' ensures that the upper, second end portion 2 ' of the upper lifting arm 22 ¹ is guided upward, in that the steering arm 8 ' keeps the lower, first end portion 23 ' of the upper lifting arm at the fourth pivot point D', simultaneously as the steering arm 8' rotates around the third pivot point C. During this movement, the first portion 29 of the plane will move from a retracted to a partially extended position in the second portion 30.

Figure 4 shows the device in a position, where the plane 31 of the device is in a raised, horizontal position, which means that both the forward, first sub-linkage 6 and the rearward, second sub-linkage 6' are raised. The course of events in the sub-linkages 6, 6', from a lowered to a raised condition, follows the description in the foregoing, with the difference that they carry out the movement simultaneously.

By means of the invention, a number of advantages are obtained over the prior art. The first sub- linkage 6 and the second sub-linkage 6' are interacting to produce the lifting and tilting movement of the plane 31.

Accordingly, only a small, substantially horizontally directed force is required from the actuator to produce a vertical actuating movement. Furthermore, a compact device is obtained, since no additional linkages are necessary. The V- shape of the pivotal lifting arm 11, 11 and its connection to the actuator 25, 25' and the link arm 16, 16' are unique, causing a low, horizontal force to be transformed into a high upward force.