A blow-molded plastic structure has a hollow interior portion formed during a blow-molding process, and includes first and second outer portions that are spaced apart from each other, with the hollow interior portion disposed there between. The structure includes a pattern of structural stiffening features that are integrally formed in the second outer portion. The pattern of structural stiffening features includes a plurality of tripodal depressions disposed in rows and columns and a plurality of convex regions disposed in rows and columns between the plurality of tripodal depressions. Each convex region has a maximum height between the first and second outer portions. Each of the tripodal depressions extends into the hollow interior portion, includes three indentations disposed adjacent the first outer portion, and includes an island spaced away from the first outer portion. The island has three sides, each of which is disposed adjacent one of the three indentations.

A blow-molded unitary structure includes a panel having first and second panel walls and a generally hollow interior between the first and second panel walls. The structure also includes one or more different types of strengthening elements monolithically formed with the panel and across a substantial portion of the panel to enhance the strength of the structure. A strengthening element can be a depression recessing from the second panel wall toward an interior of the panel, a protrusion protruding from the second panel wall toward an exterior of the panel, a rib protruding outwardly toward the exterior of the panel and a trench formed by side walls of adjacent protrusions.

A method and apparatus for the formation of double-walled containers with the structure of two integrally connected and adjacent containers extending in the same direction with an air gap between them, stretch-blow moulded as single bodies out of thermoplastic material, and suitable for mass-production. A thermoplastic tubular blank is formed and then heat-conditioned. The heat-conditioned tubular blank is then mechanically stretched longitudinally and blow-formed outwards by gas pressure to conformingly and stretchingly assume the tubular blank to the shape of a first dual-container shaped mould cavity set in order to form a stretch-blow moulded first container integrally connected to a second container, with both containers extending in opposite directions. Next, additional heat-conditioning is applied to further heat-condition as necessary the stretch-blow moulded second container and if deemed an advantage, at least part of the first container. Then at least one profiled inversion piston and a second dual-container shaped mould cavity set are provided along with one or more wall stability devices applied to at least part of the wall surface(s) of either or both of the two integrally connected stretch-blow moulded containers, such that the second container side wall(s) may be inverted at least partially inside-out, while at the same time the second container bottom wall at least substantially does not invert, in order for the second container to become a substantially mirror-image inverted second container extending in the same direction as the first container, and an air gap is formed between the first container and second container.

A plastic molded lip structure may extend along a perimeter of a planar element and may include an outer wall, an inner wall, structural portions, and protruded features. The outer wall may extend in a normal direction from the planar element. The inner wall may be disposed in an inward direction relative to the outer wall. The structural portions may be disposed along structural sections of the perimeter and may include first portions of the inner wall and of the outer wall. The first portions may be disposed parallel to the inner wall and separated from the first portions by a first distance along the structural sections. The protruded features may be interposed between two structural portions and an inner wall may be separated from second portions of the outer wall by a second distance that is greater than the first distance.

A laminated board and an application thereof. The laminated board comprises a first partial board, a second partial board, a first layer, and a second layer. The first layer is attached to the second layer, and a boundary is formed at the position where the first layer is connected to the second layer. The first partial board comprises one or two selected from the combination of at least part of the first layer and at least part of the layer. The second partial board comprises one or more selected from the combination of other at least part of the first layer and other at least part of the second layer. The first partial board and the second partial board are connected to each other at the edge and are spaced apart from each other to form a cavity. At least part of the second partial board extends to the first partial board to form at least one support structure. The first partial board can be supported in the support structure.

A method and apparatus for the formation of double-walled containers with the structure of two integrally connected and adjacent containers extending in the same direction with an air gap between them, stretch-blow moulded as single bodies out of thermoplastic material, and suitable for mass-production. A thermoplastic tubular blank is formed and then heat-conditioned. The heat-conditioned tubular blank is then mechanically stretched longitudinally and blow-formed outwards by gas pressure to conformingly and stretchingly assume the tubular blank to the shape of a first dual-container shaped mould cavity set in order to form a stretch-blow moulded first container integrally connected to a second container, with both containers extending in opposite directions. Next, additional heat-conditioning is applied to further heat-condition as necessary the stretch-blow moulded second container and if deemed an advantage, at least part of the first container. Then at least one profiled inversion piston and a second dual-container shaped mould cavity set are provided along with one or more wall stability devices applied to at least part of the wall surface(s) of either or both of the two integrally connected stretch-blow moulded containers, such that the second container side wall(s) may be inverted at least partially inside-out, while at the same time the second container bottom wall at least substantially does not invert, in order for the second container to become a substantially mirror-image inverted second container extending in the same direction as the first container, and an air gap is formed between the first container and second container.

A blow-molded plastic structure, such as a tabletop, may include an undercut. For example, the tabletop may include a frame receiving portion and a frame connecting structure with an undercut may be disposed in the frame receiving portion. A portion of the frame may contact or engage the frame connecting structure, such as the undercut, when the frame is connected to the tabletop. In an exemplary embodiment, a first side of the frame receiving portion may include a first frame connecting portion with an undercut and a second side of the frame receiving portion may include a second frame connecting portion with an undercut. The first frame connecting portion with an undercut may be disposed on an opposing surface from the second frame connecting portion with an undercut.

A blow-molded plastic structure, such as a tabletop, may include an undercut. For example, the tabletop may include a frame receiving portion and a frame connecting structure with an undercut may be disposed in the frame receiving portion. A portion of the frame may contact or engage the frame connecting structure, such as the undercut, when the frame is connected to the tabletop. In an exemplary embodiment, a first side of the frame receiving portion may include a first frame connecting portion with an undercut and a second side of the frame receiving portion may include a second frame connecting portion with an undercut. The first frame connecting portion with an undercut may be disposed on an opposing surface from the second frame connecting portion with an undercut.

A blow-molded unitary structure includes a panel having upper and lower panel surfaces and a ridge extending downward beyond the lower panel surface. The ridge includes a first side surface, a second side surface, and a lower ridge surface joined with the first side and second side surfaces of the ridge. The ridge further includes a plurality of depressions formed at one or more of the first side surface, second side surface and lower ridge surface. The plurality of depressions enhances the strength of the ridge, and the ridge in turn enhances the strength of the structure.

A blow-molded unitary structure includes a panel having first and second panel walls and a generally hollow interior between the first and second panel walls. The structure also includes a plurality of depressions, or at least one ridge, or both the depressions and ridge to enhance the strength of the structure. The plurality of depressions is monolithically formed with the panel, recessing from the second panel wall toward the first panel wall. A depression has a side wall composed of first and second segments. Cross-sectional-wise, the first and second segments have different widths and thus collectively forms a step between the first and second segments. A ridge is also monolithically formed with the panel and includes a section, at which the width of the ridge varies along the height direction of the ridge.