A blow-molded plastic frame of a portable collapsible sign includes a first outer portion, a second outer portion spaced apart from the first outer portion, and a pattern of structural stiffening features formed in the first and second outer portions. The pattern comprises rows and columns of first depressions extending from the first outer portion into a hollow interior portion between the first and second outer portions, and rows and columns of second depressions extending from the second outer portion into the hollow interior portion. Each first depression has a first floor comprising three first arms having rotational symmetry. Each first arm is rotated from another first arm by 120 degrees. Each second depression has a second floor comprising three second arms having rotational symmetry. Each second arm is rotated from another second arm by 120 degrees. The first floor of each first depression is aligned with the second floor of an adjacent second depression.

In an embodiment, a method for the manufacture of an injection molded article in an injection mold comprises at least one flow length of at least 50 cm, the flow length being defined as the shortest distance between a point of injection in the mold and an inner mold wall, the method comprising injection molding a polycarbonate composition comprising an aromatic polycarbonate, from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition of an epoxy additive having at least two epoxy groups per molecule, and from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition of a phenolic diphosphite derived from pentaerythritol.

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.

A structure, such as a tabletop, may be constructed from plastic, such as blow-molded. The tabletop may include an upper surface, a lower surface, and a hollow interior portion disposed between the upper surface and the lower surface. A lip may extend downwardly relative to the lower surface of the tabletop, and the lip including an outer surface and an inner surface. A plurality of supports may be disposed in the inner surface of the lip, and a plurality of joints may be disposed in the inner surface of the lip. A joint may be disposed between adjacent supports. A distal portion of the lip may include a compression edge. A lower portion of the supports may contact the compression edge, and/or a lower portion of the joints may contact the compression edge.

A process for the production of manufactured articles in composite material comprises at least one supply phase of a plurality of layers and at least one coupling phase of the layers. The coupling phase comprises at least one step of arrangement of the layers overlapped onto each other to create at least one stratified body. The coupling phase comprises at least one step of positioning the stratified body inside a mould. The coupling phase comprises at least one firing step of the layers positioned inside the mould. The supply phase comprises at least one supply step of at least one basic layer and at least one supply step of at least one reinforcement layer.

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 table has a bottom plate having a bottom plate channel and an outer wall. A bottom plate lip is perpendicular to the outer wall. A top plate has a top plate lip overlying and parallel to the bottom plate lip. A lower end of a frame is in the bottom plate channel and an upper end of the frame is in contact with the top plate. An edge piece clamps the top plate lip and the bottom plate lip together. The edge piece extends entirely around a perimeter of the top plate.

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 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.