DK174580B1 - Chair, preferably wheelchair, with swivel backrest - Google Patents

Description

DK 174580 B3

The present invention relates to a chair, preferably a wheelchair, comprising a seat and a backrest, each comprising a frame and a cushion, the backrest being pivotal to the seat.

5 In chairs of this type, where the backrests and armrests can be swung and / or adjusted in relation to the seat, are especially used for wheelchairs for people with disabilities. However, a chair according to the invention may also be applicable to other chairs, such as office chairs, car seats and the like.

Typically, a backrest is adjusted relative to the seat by pivoting the backrest around a pivot point attached to a frame or frame located under the seat. Such an oscillation is undesirable for anatomical reasons, with the extension of the seatback position relative to the seat. This is especially a disadvantage for people with disabilities or persons with reduced mobility, where a wheelchair must be arranged to meet several needs. Thus, in such a wheelchair there is a need for the person's back to be positioned correctly relative to the upholstery and the like, for example due to back deformities. In order to get relief from a normal upright posture, there is also a need for the user to swing the backrest while establishing a neutral position so that the user can maintain his back in a correct position against the backrest regardless of the angle of swing. This is also important in the interests of the user, who has auxiliary equipment in the form of controls mounted on the backrest frame and which is operated by the user's head. Thus, it is important that control rods operated by the forehead or mouth are positioned correctly relative to the user. In other users, a head restraint is made for the backrest. In this situation, it is also important that a pivot can be established where the upper body of the user is in a neutral position with respect to the backrest, so that the main fixation is not loosened or unnecessarily tightened on the user. The known chairs do not meet these needs. When the backrest is pivoted relative to the seat, a neutral pivot is not achieved, with the backrest following the natural pivot of the user's upper body relative to the seat. This gives rise to incorrect backing of the user's back, resulting in a risk of discomfort or significant injury to the user.

Furthermore, the extension of the backrest relative to the seat will cause the wearer's clothing to be pulled apart. This provides a discomfort for the user. A DK 174580 B3 2 such discomfort will be experienced in office chairs or the like, regardless of whether the chair has a backrest that is individually adapted to the user's fabric.

From US Patent Nos. 3,934,929 and 5,636,898, a chair is known in which the backrest 5 is pivoted about an axis corresponding to the theoretical position of the user's hip joint when the user sits upright in the chair.

In these writings, it is assumed that the upper and lower body pivot relative to one another about a fixed axis corresponding to the theoretical position of the patient's hip joint in the sitting position. This results in a swing of the backrest relative to the seat, where there is a shift of the user's back in relation to the backrest, which displacement grows with increasing swing angle.

Thus, in the known chair structures of the type mentioned in the introduction, a simple solution is not provided, which allows the backrest to be pivoted in a neutral manner relative to the upper body of the user, so that it supports correctly and is in a substantially fixed position in relation to for the backrest.

It is the object of the present invention to provide a solution which meets the above-mentioned needs and which alleviates the disadvantages of the prior art chairs.

This is achieved according to the present invention with a chair of the type mentioned initially, which is characterized in that the backrest is arranged for pivoting according to a path in which the backrest extends as a tangent to a curve which is approximately circular and which has a center located in front of the backrest cushion and above the seat cushion in a position, preferably approx. 100 mm, in front of and above the person's abutment point against the backrest and against the seat when the cushions are compressed, as the backrest pivots a largely fixed position of the user's upper body relative to the backrest.

With the chair according to the invention, it has surprisingly been found that with different subjects an ergonomically correct positioning of the person in relation to the backrest is achieved during its swing. Thus, it has surprisingly been found that a chair having the backrest positioned, as claimed in claim 1, does not create any extension but, on the other hand, DK 174580 B3 3 creates a neutral oscillation where the upper body of the user is in a substantially fixed position in relation to for the backrest regardless of whether the backrest is swung through large pivot angles.

Surprisingly, the reclining arm was required to make a pivotal motion according to a path as claimed in claim 1, wherein the center of the circle mentioned in the claim is substantially higher than as disclosed in U.S. Patent 3,934,929 and U.S. Patent 5,636,898.

It will be possible to establish the back movement of the backrest relative to the seat according to 10 different design principles. Each of these design principles can be varied in different ways to align the curve with a shape which, as indicated in the claim, is approximately a circle.

A first principle is to have the backrest steer in a curved track, which is attached to the seat frame or to the chair frame. Such control in a groove can be accomplished by engaging two pins with the groove and controlling the backrest movements, establishing the swivel movement of the chair using a linear actuator located under the seat of the chair. This can be said to be a curve disc arrangement. Alternatively, the curve disc arrangement may also be formed by a single pin engaging a curve disc at one side of the seat or at each side of the seat and another point of the backrest frame being fixed to the actuator under the seat.

According to another principle, the backrest can be mounted for pivoting about a point which is the center of the curve movement. Here, too, the backrest will be moved by a linear actuator under the 25 seat. However, while this construction is possible, it will be disadvantageous as a frame arrangement is required which is located at each side of the seat in a position above the seat and in front of the back. This can make getting in and out of the chair difficult.

30 A third option is the use of a management arrangement. In a guide arrangement, a curve movement with the backrest can be made following the curve of the curve path by placing a double joint system under the backrest. A chair constructed according to this principle may be distinctive in that the guide arrangement between the seat and the backrest includes a central actuator acting on a first arm fixedly connected to a shaft, which at each end is provided with a second arm which, by means of a rotation pin, engages a third arm on each side of the backrest, said third arms being pivotally mounted on each bracket mounted on each side of the seat frame.

5

It should be noted that the backrest of a chair according to the invention can swing from a substantially vertical position through 90 ° to a substantially horizontal position. Especially at larger angles a noticeable effect is experienced between a chair according to the invention and the chairs arranged according to the two aforementioned US patents.

10

The invention will then be explained in more detail with reference to the accompanying drawing, in which fig. 1 is a partial schematic view illustrating a chair seat, backrest, and armrest for a chair according to the invention with the backrest positioned in an upright substantially vertical position; 2 shows a view similar to FIG. 1 with the backrest and armrest in a reversed position; FIG. Figure 3 is a schematic view illustrating the principle of the backrest pivot; 4 is a partial view illustrating two starting positions for an armrest in a chair according to the invention; FIG. 5 shows an image to illustrate the armrest swing at the same time as the backrest swing, 25 fig. 6 is a perspective view illustrating a bracket for a chair according to the invention; and FIG. 7 and 8 show images similar to FIG. 1 and 2, but with various elements omitted from the drawing, to more clearly illustrate the connection between the backrest and the seat. 1 FIG. 1 is a partial view of a chair 1 according to the invention. The chair 1 is shown with the chair's backrest 2 in its erect almost vertical position and with the chair's armrest 3 in a substantially horizontal position at a height above the chair's seat 4. The chair has a backrest cushion 5, an aiming cushion 6 ' and a seat cushion 6. The cushions are respectively mounted on a backrest frame 7, an armrest frame 8 and a seat frame 9. The backrest 2 is arranged to be able to swing relative to the seat 4. The oscillation is effected by means of a linear actuator 10 mounted in the a bracket 11 which is secured in a central position on the seat frame 5 9. The actuator operates a guide arrangement 12 to actuate the backward oscillation of the backrest 2. The guide arrangement 12 comprises a first arm 13 rotatably mounted to a piston in the actuator 10. The arm 13 is firmly connected to a shaft 14 extending to each side of the seat. At each end of shaft 14, another arm 15 is provided.

The arm 15 is provided at its end with a rotation pin 16, which engages a 10 groove 17 in a third arm, which is constituted by a bracket plate 18 at each side of the backrest 2.

A third arm or bracket plate 18 is pivotally mounted via the rotation pin 19, which is mounted on bracket plates 20 at each side of the seat frame 9. Thus, the center axis of the rotation pins 19 will form a center of pivot 2's pivot.

The rotation pins 19 will be positioned so that the center axis is approximately 100 mm in front of the backrest and above the seat measured from the person's abutment points against the backrest and seat when the cushions 5,6 are compressed. This distance of approximately 100 mm corresponds to that of an adult. In the case of a child, this distance will be less for the backrest and seat.

20

The bracket plates 20 are provided with a groove 21 which is used to control the swing of the armrest 3. The frame of the armrest 3 comprises a flat tube 22 on which the armrest cushion 6 'is mounted. The tube 22 is mounted via a bracket 23 at one end 24 of a U-shaped bracket 25. The bracket 25 is rotatably mounted at its other end about a rotation 25 pin 26 which is mounted on the backrest. Thus, the armrest is pivotally mounted relative to the backrest 2 and is simultaneously pivotable relative to the seat 4.

At an intermediate position on the bracket 25, a bracket 23 'is provided which is provided with a rotation pin 27 which cooperates with the groove 21 in the bracket 20. In the rearward swinging of the backrest 2, the armrest will be swung upwards, but this will occur during a half angle with respect to the backrest oscillation, as the groove 21 is a largely cardioid shaped groove. These relationships are more clearly seen in FIG. 5th

DK 174580 B3 6 If the backrest is swiveled back and the armrest makes a partial swing, the user's arm will remain positioned on the armrest cushion 6 ', and the user can easily and effortlessly activate an operating bracket attached to the armrest and no angles of rotation will occur, which are uncomfortable or inelegant in the user's elbow, hand or 5 shoulder.

In FIG. 2 is the one shown in FIG. 1 in a position where the backrest 2 is pivoted approx. 60 ° backwards relative to its original vertical position. At the same time, the armrest has been swung through approx.

30 °. It will be seen that, at the oscillation of the backrest, the rotation pin 27 has passed through the groove 10 21 and is now at the lower part of the groove 21 in the bracket 20. From fig. 2, it is also seen that the actuator 10 located centrally below the chair seat has its piston in a deferred position, whereby the first articulator 13 has rotated the shaft 14 and thus pivots the second articulator 15 forward. During the forward swing of the guide arm 15, the rotation pin 16 may be displaced in the track 17. Thus, the track 17 has a length which causes the rotation pin 16 to be in the outer position shown when the chair is fully upright and in its position where the rotation is 60 °. back, which in the embodiment shown is the maximum back swing for the backrest 2.1 of the chair an intermediate position, the rotation pin 16 will be located at the other end of the track 17. The track 17 thus enables the swing of the backrest 2 to rotate about the rotation pins 19 in such a way that the backrest 20 2 is continuous as a tangent to a circle with the center of the center of rotation pin 19. The rotation pin 27 is a spring-loaded pin which can be pulled out of engagement with the groove 21. This allows the armrest to pivot around the rotation pin 27, so that the armrest 3 can be pivoted to a position behind the backrest 2 or below the seat 4 for ease of engagement. and ascent to the chair 1.

25 in FIG. 7 and 8, images of the chair 1 corresponding to FIG. 1 and 2.1 FIG. 7 and 8, the armrest 3, the bracket 25 and its mounting are omitted, as are the backrest cushions 5. Hereby is seen more clearly the guide arrangement 12 which establishes the connection between the backrest 2 and the seat 4. In the case of identical elements, no specific explanation will be given to FIG. 7 and 8. In FIG. 3, 28 indicates a line for the person's abutment point or abutment surface against the seat when the seat cushion is compressed due to the person's weight. 29 similarly indicates a plane of the person's abutment point or abutment surface against the backrest when the backrest cushion is compressed due to the person's weight. 30 indicates a center of a circle which is a tangent curve to the backrest positions during the pivot. 31 indicates the distance of the center 30's position above surface 28. 32 indicates the distance from the center 30 to the abutment abutment surface 29. The distances 31,32 will preferably be approx. 100 mm for an adult. In FIG. 3, a vertical position is illustrated where it is seen that the surface 29 extends as a tangent to the circle 33. Then a position of the back of the back is shown through 30 °, where the plane of the backrest 29 ', 29 "and 29'" is still tangent. to the circular arc 33. It should be noted that in practice a backrest will be arranged for a backward swing through approx. 60 °. A lowering of the backrest to a horizontal position will occur only in rare cases.

FIG. 4 shows an armrest 3 in two different positions above the seat. The height adjustment of the armrest 3 above the seat 4 is thus done by loosening the bracket 23 'and displacing it along the bracket 25 until the armrest 3 has a desired exit height above the seat 4. When the armrest has the desired height, the bracket 23 is released and the armrest is applied horizontal position, after which the bracket 23 is again clamped.

✓ * In fig. 5, the armrest 3 is seen in an initial position with an approximately vertical orientation 20 and in a position where it is swung through 30 ° corresponding to a back swing of the backrest through 60 °. It is seen that during rotation of the armrest, the rotation pin 27 is shifted from a position in the upper part of the groove 21 to a position at the bottom of the groove by the backward swing of the backrest through 60 °.

In the following, an embodiment of the aforementioned bracket 23 (and 23 ') will be explained with reference to FIG. 6. The assembly bracket 23 comprises a first side plate 37 and a second side plate 38. Each of the side plates is provided with a groove 39 capable of accommodating the sides of the flat oval tubes used to manufacture the frame frames and frame. The second side plate is firmly connected to a cone-shaped pin 40. An intermediate piece 41 having a cone-shaped bore 42 is intended for placement over the cone-shaped pin 40 and serves as a spacer adapted to the width of the flat oval tubes. , such that a clamping of the bracket 23 by means of a nut 42, which is screwed into a thread 43 in the pin 40, ensures that the bracket is fixed to the flat oval tube. At the same time, the spacer is fixed in a rotationally fixed position by the engagement of the cone surfaces.

The intermediate piece 41 may be provided with a welded bracket for a spring loaded pin S 27, which is used to control arm movement. The spacer 41 may also be provided with a stud by which it is mounted or welded at the first end 24 of the bracket 25. Hereby the spacer 23 may serve to secure the armrest 3. When the bracket 23 is used in connection with the bracket 25, the grooves 39 will be curved with a curvature corresponding to the curvature of the bottom of the U-shaped bracket 25.

10

The bracket 23 can be loosened easily and at the same time can be longitudinally displaced by displacing the bracket along a pipe in the grooves 39 and at the same time adjusting the rotational position of the spacer 41 with respect to the side plates 37,38. The bracket 23 can thus be used in a simple manner for securing part elements to the chair.

15

Above, the invention is specifically described in connection with backrests 2, armrests 3 and seat 4. These elements can be used in different types of chairs where one wants to achieve a neutral swing of the backrest. Such chairs can, for example, be used in wheelchairs, in commercial vehicles, at dentists or medical clinics.

Claims (5)

A chair, preferably a wheelchair, comprising a seat and a backrest, each comprising a frame and a cushion, wherein the backrest is pivotable relative to the seat, characterized in that the backrest is adapted for pivoting according to a track, wherein a plane substantially following the surface of the backrest cushion, when compressed by the user in a position seated in the chair with the seat horizontal and the backrest vertical and the seat cushion also compressed by the user, extends as a tangent to a curve located in a seat a plane perpendicular to both the seat and the backrest, which is approximately a circle which, in the aforementioned compressed state of the backrest and seat cushions, has its center located substantially the same horizontal distance from the surface of the backrest cushion as the axis of rotation; which, in theory, passes through the hip joint of the utility spring, and at a substantially greater height above the surface of the seat cushion than the corresponding height of said axis, Each horizontal distance of the center is preferably 100 mm and at which height the center is also preferably 100 mm. 2. A chair according to claim 1, characterized in that the backrest is connected to the seat via a guide arrangement or a curve plate arrangement. Chair according to claim 1 or 2, characterized in that the curve disc arrangement comprises a plate with a curved groove which cooperates with a rotational pin which can be engaged with the groove and which is arranged to be displaced through the groove by pivoting the backrest. Chair according to any one of claims 1-3, characterized in that the conductor arrangement between the seat and the backrest comprises a central actuator acting on a first arm fixedly connected to a shaft mounted on one of the seats. end of said first arm, which is provided at each end with a second arm which engages a third arm on each side of the backrest via a rotation pin, the rotation pin engaging a groove in said third arm, which third arms are pivotally mounted on each bracket mounted on each side of the seat frame. DK 174580 B3 10 Chair according to any one of the preceding claims, characterized in that the backrest is arranged to perform a rearward swing through approx. 60 * from a vertical position.