Device for supporting a load

1. A device for supporting a load comprising;

a fixed lower platform having a first connecting area;

a movable upper platform having an operating area and a second connecting area;

at least three limbs, each limb comprising a lower section, an upper section and an intermediate section between said lower section and said upper section;

wherein each limb interconnects said fixed lower platform and said movable upper platform by joining said first connecting area and said second connecting area,

wherein said lower section of each limb comprises a first part of a first prismatic joint,

wherein, the first connecting area comprises a cooperating second part of said first prismatic joint, wherein the first prismatic joint is arranged for movement along a first axis;

wherein said lower section of each limb further comprises a first revolute joint in attachment with the first part of the first prismatic joint, wherein the first revolute joint is arranged for movement around a second axis, the second axis being parallel to the first axis;

wherein said intermediate section of each limb comprises a second prismatic joint being extendable along a third axis defined by the axis of extension of the intermediate section,

wherein said upper section of each limb comprises a second revolute joint attached to said second connecting area, wherein the second revolute joint is arranged for movement around a fourth axis being parallel to the second axis;

wherein each limb is pivotably movable relative to said movable upper platform;

wherein each of said limbs comprise an actuation arrangement for moving the movable upper platform relative to the fixed lower platform, wherein said second prismatic joint in said intermediate section of each of said at least three limbs further comprises a lower body and an upper body, wherein a first support structure extends from said lower section to said upper body, traversing said lower body, wherein a second support structure extends from said upper section to said lower body, traversing said upper body, wherein said actuation arrangement is attached to at least a part of one of said upper body or lower body, allowing for a slidable relative motion of the upper body to the lower body, and wherein one of said first or second support structures forms a part of said actuation arrangement, said actuation arrangement further comprising a device for driving said one support structure linearly.

2. The device for supporting a load according to claim 1 , wherein said first part of said first prismatic joint comprises a bearing carriage;

wherein said second part of said first prismatic joint comprises;

a rail arrangement provided on said first connecting area;

wherein said first part of said first prismatic joint is slidably attached to the rail arrangement, allowing for linear motion along said rail arrangement.

3. The device for supporting a load according to claim 1 , wherein the first prismatic joint is provided with a second actuation arrangement for controlling the position of the lower section of each limb along the first axis.

4. The device for supporting a load according to claim 1 , wherein said rail arrangement comprise at least three straight rail tracks, wherein said rail arrangement form a polygonal shape, wherein each bearing carriage is slidably attached to a respective rail track.

5. The device for supporting a load according to claim 1 , wherein said limbs extend from said fixed lower platform to said movable upper platform in a tapered manner, or in a reverse tapered manner or in parallel with each other.

6. The device for supporting a load according to claim 1 , wherein said movable upper platform only has three translational degrees of freedom.

7. The device for supporting a load according to claim 1 , wherein said second prismatic joint in said intermediate section of each of said at least three limbs further comprises a lower body and an upper body, wherein said actuation arrangement comprises a shaft, extending from said lower section to at least said upper body, said shaft being linearly guided.

8. The device for supporting a load according to claim 1 , wherein said movable upper platform is parallel to said fixed lower platform independently of its position.

9. The device for supporting a load according to claim 1 , wherein a torsional force applied to the movable upper platform is substantially supported by the lower body and upper body.

10. The device for supporting a load according to claim 1 , wherein the position of the first prismatic joint and the second prismatic joint are known and the location of the movable upper platform is determinable via forward kinematics.

11. The device for supporting a load according to claim 1 , wherein upper portion of each limb has a smaller distance to a centre axis (C) relative the distance of the lower portion of each limb.

12. A method for supporting a load with the device according to claim 1 , wherein the method comprises:

applying a load to the movable upper platform; and,

determining the position of the movable upper platform relative the fixed lower platform.

13. The method according to claim 12 , wherein the method further comprises:

adjusting the position of the load via displacing the second prismatic joint.

14. A prismatic joint comprising a lower body and an upper body, wherein a first support structure extends from a lower section of the prismatic joint to the upper body, the first support structure traversing the lower body, wherein a second support structure extends from an upper section of the prismatic joint to the lower body, the second support structure traversing the upper body, wherein the prismatic joint is provided with an actuation arrangement, the actuation arrangement attached to at least a part of one of said upper body or the lower body, and wherein one of the first or second support structures forms a part of said actuation arrangement, the actuation arrangement further comprising a device for driving the support structure linearly.