A stackable lid, for closing of container bodies,
- a) said lid being made of a material having a generally uniform thickness,
- b) said lid comprising at least a generally horizontal lid panel, having a generally flat shape and a lid perimeter and an imaginary vertical axis, which is perpendicular to the lid panel,
- c) said lid being intended to be stacked, one lid on top of the other, in a vertical parallel stack, wherein vertical indicates that the stack is in the direction of said imaginary vertical axis, and wherein parallel indicates that the lids in the stack and their individual lid panels are parallel to each other, and wherein
- d) each individual lid in the stack is intended to provide a solid base to carry and support the next lid above it in the stack, so that the stack feels solid and so as to prevent vertical movement of the lids within the stack,
- e) said lid further comprising certain irregularly shaped elements, protruding outside and beyond the generally flat shape of the lid panel,
- f) said lid further comprising a lid lip, located outside said lid panel, along and adjacent to said lid perimeter, for joining said lid lip to a corresponding lip of the container bodies to be closed by said lid, thus creating a seam, and said lid lip, having a lid lip height above the generally flat shape of the lid panel, and wherein said seam will have a certain expected seam height above the generally flat shape of the lid panel, and
- g) said lid further comprising an outer ramp, located as a transition between the lid lip and the lid panel, said outer ramp being shaped as a concave portion, when looking down at the lid in a top view, and running along the lid lip and the lid perimeter,
- h) said outer ramp, starting adjacent to the lid lip, then extending downwardly and inwardly, when looking at it in a cross-sectional view of the lid, then joining the lid panel,
- i) said outer ramp itself comprising at least four distinct portions, a skirt, an outer knee, an outer lower leg, and an outer heel,
- j) said skirt, starting generally near the lid lip then extending downwardly and inwardly and having a skirt length, and a skirt angle, with respect to the imaginary vertical axis,
- k) said outer knee, being disposed below the skirt and acting as a transition between the skirt and the outer lower leg, and starting at the end of the skirt and ending at the outer lower leg,
- l) said outer lower leg, starting at the end of the outer knee, then extending downwardly and inwardly, having an outer lower leg length, and an outer lower leg angle, with respect to the same imaginary vertical axis, wherein the shape of the outer lower leg creates a sloping lower leg flank and being disposed below the skirt and the outer knee,
- m) said outer heel, being located at the end of the outer lower leg, and shaped to end up joining the lid panel, wherein
- n) said outer knee, is shaped, so that together with the skirt and the lower leg, they form a curve, that looks like an upper-case letter “Z” or letter “S”, when looking at it in a cross-sectional view of the lid, said outer knee acting as a supporting ledge,
- o) the skirt angle is larger than the outer lower leg angle, wherein the outer lower leg angle is steeper than the skirt angle, and wherein
- p) when any two said stackable lids are stacked one on top of the other, the lower stacked lid provides a solid heel over knee interface and support to the upper stacked lid, wherein the heel of the upper stacked lid will rest on top of the knee of the lower stacked lid, ensuring that the stack feels solid, so as to prevent vertical movement of the lids within the stack and to keep the lids and their lid panels horizontal and parallel to each other within the stack, and wherein
- q) the skirt of the lower stacked lid will not touch the outer lower leg of the upper stacked lid, because the skirt angle, being larger than the outer lower leg angle, creates a skirt clearance angle and a skirt clearance space between the skirt of the lower stacked lid and the outer lower leg of the upper stacked lid, and wherein
- r) the only contact between the two stacked lids will occur only at the solid heel over knee interface which is between the heel of the upper stacked lid and the knee of the lower stacked lid, which is supporting said upper stacked lid, and that at any position during a rotation of one stacked lid with respect to the other stacked lid, all the other elements of the two stacked lids are sufficiently spaced apart vertically, so that there will be no contact between any of these other elements of the two stacked lids, wherein
- s) a minimum vertical stacking height is defined and measured as the vertical distance starting at the solid heel over knee interface between the heel of the upper stacked lid and the knee of the lower stacked lid of a first pair of stacked lids in a stack, and ending at the comparable solid heel over knee interface between the heel and the knee of the pair of stacked lids, which is immediately above or below said first pair, and wherein
- t) said required minimum vertical stacking height is provided by selecting the proper shapes and dimensions of the heel and the knee of the stacked lids, and by the length of the outer lower leg of the stacked lids, and wherein
- u) said minimum vertical stacking height is chosen to be large enough, so as to ensure that the only contact between any pair of stacked lids, at any relative rotational position between the upper stacked lid and the lower stacked lid of said pair of stacked lids, will occur only at the solid heel over knee interface between the heel of the upper stacked lid and the knee of the lower stacked lid, which is supporting said upper stacked lid.