Abstract
An item of seating furniture having a sitting surface which is mounted on a frame structure and which can be lifted from a lower position to an upper position by means of a lifting device, said lifting device having a scissors mechanism that has at least two limb parts which can pivot relative to each other. At least one spring element which is prestressed in the lower position, acts in the direction of the upper position and can be arranged in at least two different angular positions engages with at least one of the limb parts which is mounted via an articulated joint to the frame structure.
Claims
1. An item of seating furniture with a sitting surface mounted on a frame structure and which is liftable from a lower position to an upper position with a lifting device, wherein the lifting device has a scissors mechanism with at least two limb parts which pivot relative to each other, wherein an actuator, arranged in at least two different angular positions, acts on at least one of the limb parts; wherein the actuator is a spring element pre-stressed in the lower position and acts in a direction of the upper position, wherein one end of the spring element is held in a spring bearing connected to one of the limb parts and the other end of the spring element is held in a counter-bearing connected to the frame structure by a connecting member suspended at a first end of the connecting member relative to the frame structure and pivotally supporting the counter-bearing at a second end of the connecting member.
2. The item of seating furniture according to claim 1, wherein the spring element is connected to at least one control element for adjusting an angular position and a lifting force of the spring element.
3. The item of seating furniture according to claim 2, wherein the control element has at least two parts, adjustable relative to each other in a longitudinal direction.
4. The item of seating furniture according to claim 2, wherein the control element is arranged between the counter-bearing of the spring element and the frame structure.
5. The item of seating furniture according to claim 2, wherein the control element is connected in an articulated manner to a connection arm, wherein the connection arm is connected in an articulated manner to the counter-bearing of the spring element and the frame structure.
6. The item of seating furniture according to claim 2, wherein the limb parts are arranged in such a way that the lifting force between the upper position and the lower position of the sitting surface is constant irrespective of the angular position of the spring element.
7. The item of seating furniture according to claim 1, wherein the spring element is connected to a damper element arranged in an inside of the spring element.
8. The item of seating furniture according to claim 7, wherein the damper element is blocked to lock the sitting surface.
9. The item of seating furniture according to claim 8, wherein the damper element is connected via a connection to an activating device in an area of an arm rest, wherein the connection is a tension cable.
10. The item of seating furniture according to claim 1, wherein one limb part of the at least two limb parts engages on a front sitting area and the other limb part of the at least two limb parts engages on a rear sitting area of the sitting surface, wherein the front sitting area and the rear sitting area are connected to each other in an articulated manner.
11. The item of seating furniture according to claim 10, wherein the front sitting area and the rear sitting area in the lower position of the seating surface are arranged in one plane, wherein the front sitting area in the upper position of the sitting surface is arranged inclined downwards away from the rear sitting area.
12. The item of seating furniture according to claim 1, wherein at least one of the limb parts is connected in an articulated manner to a crank lever.
13. The item of seating furniture according to claim 3, wherein the control element is arranged between the counter-bearing of the spring element and the frame structure.
14. The item of seating furniture according to claim 5, wherein the limb parts are arranged in such a way that the lifting force between the upper position and the lower position of the sitting surface is constant irrespective of the angular position of the spring element.
15. The item of seating furniture according to claim 9, wherein one limb part of the at least two limb parts engages on a front sitting area and the other limb part of the at least two limb parts engages on a rear sitting area of the sitting surface, wherein the front sitting area and the rear sitting area are connected to each other in an articulated manner.
16. The item of seating furniture according to claim 11, wherein at least one of the limb parts is connected in an articulated manner to a crank lever.
17. The item of seating furniture according to claim 3, wherein the control element is a gas spring or a threaded rod element.
18. The item of seating furniture according to claim 7, wherein the damper element is a gas pressure spring or an oil damper.
Description
BRIEF DESCRIPTION OF THE FIGURES
(1) The invention will be described in more detail below by means of a preferred example of the embodiment shown in the drawings, to which, however, it is not restricted. In detail, in the drawings:
(2) FIG. 1 shows a side view in partial cross-section of an item of seating furniture in accordance with the invention, with a scissors mechanism to raise the sitting surface, wherein a spring element acting on the scissors mechanism is arranged in a first angular position corresponding to a first, lesser lifting force;
(3) FIG. 2 shows a view of the item of seating furniture in FIG. 1 from the front;
(4) FIG. 3 shows a side view of the item of seating furniture in accordance with FIG. 1, 2 with the sitting surface lowered;
(5) FIG. 4 shows a view of the item of seating furniture according to the invention corresponding to FIG. 1 with the sitting surface raised wherein to increase the lifting force acting on the sitting surface the spring element is pivoted into a second angular position corresponding to a second, greater lifting force.
(6) FIG. 5 shows a view of the seating furniture shown in FIG. 4 with the sitting surface lowered;
(7) FIG. 6 shows a view of a preferred embodiment of the item of seating furniture in which the spring and/or damping element is connected via a tension cable to an activating device in the area of an arm rest of the item of seating furniture; and
(8) FIGS. 7 to 11 show views of an item of seating furniture corresponding to FIGS. 1 to 5 in an alternative form of embodiment of the invention.
DETAILED DESCRIPTION
(9) In FIGS. 1 to 3 an item of seating furniture 10 is shown which comprises a frame structure 1, a backrest 11, arm rests 12 and a sitting surface 13. According to FIGS. 1, 2 the sitting surface 13 of the item of seating furniture 10 is arranged in a raised, or upper, position, which makes it easier for an impaired person to get up from the item of seating furniture 10 or to sit down in the item of seating furniture 10. According to FIG. 3 the sitting surface 13 of the item of seating furniture 10 is arranged in a lowered or lower position which corresponds to the essentially horizontal sitting position. To move the sitting surface 13 between the lower position (cf. FIG. 3) and the upper position (cf. FIGS. 1, 2) the sitting surface 13 is connected to a lifting device with which the natural course of movement when standing up or sitting down is supported.
(10) As can also be seen from FIGS. 1 to 3, a scissors mechanism 14 is provided as the lifting device and acts between the underside of the sitting surface 13 and the frame structure 1. The scissors mechanism 14 has at least one pair of interacting limb parts 14a, 14b, wherein in the shown embodiment a further, identical, pair of limb parts 14a, 14b is provided. The limb parts 14a, 14b and/or 14a, 14b are hinged on opposite longitudinal sides of the sitting surface 13.
(11) As can also be seen from FIGS. 1 to 3, the limb parts 14a, 14b are arranged so that they can be pivoted with regard to each other. For this, the limb parts 14a, 14b are pivotably arranged about a common axle 2 which is arranged approximately centrally on the limb parts 14a, 14b. In order to allow the pivoting of the limb parts 14a, 14b during the raising and lowering of the sitting surface 13, the one limb part 14a is connected via an articulated joint 2 to a crank lever 14c which, via an articulated joint 2, is mounted on the frame structure 1.
(12) As can also be seen from FIGS. 1 to 3, the limb part 14b of the scissors mechanism 14 is connected with a spring element 16a which in the lower position of the sitting surface 13 (cf. FIG. 3) is pre-stressed so that the sitting surface 13 can be moved from the lower position into the upper position (cf. FIG. 1, 2) with the support of the spring element 16a. In the shown embodiment the spring element 16a is in the form of a helical spring which will be decompressed during the movement of the sitting surface 13 into the upper position. For force transmission to the limb part 14b the one end of the spring element 16a is held in a spring bearing 22 connected to limb part 14b, and the other end of the spring element 16a is held in a counter-bearing 23 connected with the frame structure 1.
(13) As can also be seen from the drawing, the spring element 16a can be arranged in at least one first angular position (cf. FIGS. 1 to 3) and in a second angular position (cf. FIG. 4, 5) different to the first angular position. By changing the angular position of the spring element 16a, on the one hand the angle of contact of the spring element 15a on the limb part 14b, and also the pre-stressing of the spring element 16a can be adjusted, through which the lifting force on the sitting surface 13 can be matched to the weight of the user. For this, between the counter-bearing 23 of the spring element 16a and the frame structure 1 a control element 15 is arranged which can be adjusted in length in order to adapt the angular position of the spring element 16a and to set the lifting force. In the shown embodiment the control element 15 has two parts 15a, 15b which can be adjusted longitudinally with regard to each other, wherein the one part 15b is connected in an articulated manner to the frame structure 1 and the other part 15a is connected in an articulated manner to the counter-bearing 23. In addition, the counter-bearing 23 is attached in an articulated manner to the frame structure 1 by means of a connection arm 15.
(14) As can also be seen from the drawing, the spring element 16a can be pivoted from the first, more obtuse angular position shown in FIGS. 1 to 3, into the second, more acute, angular position shown in FIG. 4, 5. To pivot the spring element 16a, the parts 15a and 15b of the control element 15 are manually pushed into each other. According to FIGS. 1 to 6, parts 15a, 15b form a gas spring. By adjusting the control element 15 the distance, dependent on the length of the control element 15, between the spring bearing 22 and the counter-bearing 23 is shortened, through which the pre-stressing of the spring element 16a and thus the lifting force acting on the sitting surface 13 is increased. In this way the resulting lifting force can be specifically set via the angular position of the spring element 16a. The various components of the lifting device, more particularly the limb parts 14a, 14b, 14a, 14b of the scissors mechanism 14 are arranged and connected to each other in such a way that the lifting force between the upper and the lower position of the sitting surface 13 is essentially constantirrespective of the angular position of the spring element 16a.
(15) As can also be seen from FIGS. 1 to 5, the spring element 16a interacts with a damper element 16b which is preferably in the form of a gas pressure spring or oil damper. The damper element 16b is arranged inside the spring element 16a. In the shown embodiment the damper element 16b has a cylinder 162b within which a piston rod 162a moves.
(16) As can be seen from FIG. 6, the damper element 16b in the shown embodiment can be blocked, so that if required the sitting surface 13 can be locked in a predetermined height position. For locking or releasing, the blockable damper element 16b is connected via a connection 233, for example a tension cable, extending within a chair leg 6, to an activating device 231, which in the shown example of embodiment is located in a front end area of the arm rest 12. The movement of the activating device 231 is transmitted via the connection 233 to a lever 232 with articulated joint 234. The lever 232 presses against a corresponding activating element of the damper element 16b, through which the blocking of the piston rod 162a relative to the cylinder 162b is released. In the blocked stated of the damper element 16b, lifting of the sitting surface 13 can be advantageously prevented, if, for example, the person using the item of seating furniture 10 leans forwards to pick up an object from the floor and therefore takes the load off the sitting surface 13.
(17) As can also be seen from FIGS. 1 to 5, the one limb part 14a is connected in an articulated manner via a profile part 3 to a front sitting area 13a and the other limb part 14b is connected in an articulated manner via a profile part 4 to a rear sitting area 13b of the sitting surface 13. The front 13a and the rear sitting area 13b are pivotably connected to each other via a joint 5. Through this further relieving of impaired persons can be achieved when they are sitting down. In the shown embodiment the front sitting area 13a has a front edge which is bent downwards. Additionally, the front sitting area 13a is much narrower than the rear sitting area 13b.
(18) As can also be seen from FIGS. 1 to 5, in the lower position of the sitting surface 13 the front 13a and the rear sitting area 13b are essentially arranged in one plane. Linking of the front 13a and/or rear sitting area 13b via the limb parts 14a, 14b takes place in that the front sitting area 13a in the upper position of the sitting surface 13 is arranged inclined downwards with regard to the rear sitting area 13b. In the upper position the rear sitting area 13b is also lightly tilted down with regard to the horizontal.
(19) As can also be seen from FIGS. 1 to 5 the item of seating furniture 10 has four chair legs 6, which are each provided with castors 17a, 17b for rolling the item of seating furniture 10 on a floor surface. Here it is envisaged that the front castors 17a are designed to be laterally pivotable, whereas the rear castors 17b are not laterally pivotably, but, instead, are each provided with a braking device 18. In order to prevent the item of seating furniture 10 rolling away backwards when a person is sitting down or standing up, the braking device 18 is provided which can block or release the rear castors 17b depending on the setting. For this a manually operated braking lever can be provided with which the braking device 18 can be locked or unlocked.
(20) In an alternative embodiment (not shown), it is envisaged that the braking device 18 is automatically blocked when the sitting surface 13 is raised by a predetermined distance, for example 40 mm, from the lower sitting position. In this way the item of seating furniture 10 is secured against an unintentional (backwards) movement, whereas at the same time a movement forwards can take place without perceptible resistance.
(21) In FIGS. 7 to 11 an alternative embodiment of the invention is shown in which in the following only the differences with regard to the embodiment according to FIGS. 1 to 6 are described. In this embodiment the control element 15 also has parts 15a, 15b which can be adjusted with regard to each other, but which together form a threaded rod element. The threaded rod element can be adjusted with a hand wheel or an Allen key in order to match the angular position of the spring element 16 to the weight of the user.
