Patent attributes
A frame element includes a first scissor including a first and a second strut pivotably connected to each other at a first pivot point, a second scissor including a third and a fourth strut pivotably connected to each other at a second pivot point, and a hub to which the first and the third strut are pivotably connected, the first and second scissors being pivotable about the hub between a closed position in which the first, second, third, and fourth struts are substantially parallel to one another and an open, locked position in which the first and third struts define a non-zero angle with each other and abutment portions of the second and fourth struts contact receiving portions of the third and first struts, respectively, and prevent the first and third struts from pivoting beyond the non-zero angle.
