A lockable coupling device for a folding device comprising at least three substantially planar folding elements arranged in a frame, wherein the at least three substantially planar folding elements include a first folding element and a second folding element neighboring the first folding element, wherein the first folding element is pivotably connected to the second folding element about a substantially vertical axis;
- the lockable coupling device comprising:
- a first coupling element and a second coupling element configured to releasably lock with each other, wherein the first coupling element is configured to be arranged at the first folding element and the second coupling element is configured to be arranged at the second folding element in a mounted position, wherein the first and second coupling elements are configured to engage each other and latch in a latched position;
- a locking device comprising a sliding element slidably arranged on the second coupling element in a direction substantially perpendicular to a plane of the second folding element, when the second coupling element is arranged in the mounted position, wherein the sliding element has a length extension, wherein the sliding element comprises a leading part and a rearward part, wherein the leading part and the rearward part are arranged opposite each other, viewed in said length extension;
- wherein the leading part of the sliding element comprises a locking member and projects past a leading edge of a horizontal boundary part of the second folding element, when the second coupling element is arranged in the mounted position, wherein the leading edge is facing the second coupling element;
- wherein the rearward part of the sliding element projects past a rearward edge of the horizontal boundary part of the second folding element, when the second coupling element is arranged in the mounted position, wherein the rearward edge is facing away from the second coupling element;
- wherein the rearward part of the sliding element comprises a spring, wherein the rearward part of the sliding element is supported by the spring on a side of the second folding element that is opposite the second coupling element, when the second coupling element is arranged in the mounted position;
- wherein the rearward part is configured such that, when the second coupling element is in the mounted position and the second folding element is not in a closed position, the rearward part is arranged in a rest position projecting past the rearward edge, wherein in the rest position the locking member of the leading part of the sliding element engages by a locking action a locking receptacle of the first coupling element when the first and second coupling elements are in the latched position, wherein in the rest position the locking member contacts a guiding contour of the second coupling element such that unlocking of the locking member from the locking receptacle of the first coupling element by a pulling movement acting between the first and the second coupling elements is prevented;
- wherein the rearward part is configured such that, when the second coupling element is in the mounted position and the second folding element is moved into a closed position in the frame, the rearward part of the sliding element is configured to abut against the frame, and push the sliding element in a direction of said length extension so that the locking member of the leading part is pushed along the guiding contour out of the locking receptacle of the first coupling element and the locking action is released.