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.

Disclosed is an edge wrapping method for a composite board, the top board of the composite board surrounds the bottom board of the composite board, a part or all of the side of the top board is disposed with a connecting portion extending beyond the bottom board and extending outwardly; the adjacent portion of the connecting portion and the bottom board are heated, and then the connecting portion is folded toward the inner side of the composite board and the connecting portion is welded to the side of the bottom board. The connecting portion and the bottom board are heated, and the root portion of the connecting portion near one end of the bottom board and the position of the bottom board close to the connecting portion are heated to a molten state, and then, the connecting portion is folded, and the connecting portion and the bottom board are welded together, the production efficiency of the present invention is high, the automatic production is realized, and the product qualification rate is effectively improved.

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 plastic structure, such as a table top, may include an undercut. For example, the table top may include a frame receiving portion and a frame connecting structure with an undercut may be disposed in the frame receiving portion. A first portion of the frame may contact or engage the frame connecting structure when the frame is connected to the table top. 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 structural panel has a stiffening rib structure in which the height and width of the rib structure varies over its length. For example, the rib structure may have three tall portions separated by two short portions, with a gradual slope in height between the various portions. The rib structure is preferably wider in the short portions than it is in the tall portions. The lower height of the rib structure in some portions enhances the stiffness of the panel, while also using less material because the plastic does not have to be drawn so deeply into the mold in the short portions.

A composite table top including a top plate having an outer and an inner surface, a bottom plate comprising a plurality of projections, each of the plurality of projections having a top defining a top surface. The composite table top has at least a pair of reinforcement inserts disposed at two opposite edges of the bottom plate. The sum of the top surfaces of the plurality of projections is 30%-70% of the upper surface of the bottom plate.

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 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 structural panel has a stiffening rib structure in which the height and width of the rib structure varies over its length. For example, the rib structure may have three tall portions separated by two short portions, with a gradual slope in height between the various portions. The rib structure is preferably wider in the short portions than it is in the tall portions. The lower height of the rib structure in some portions enhances the stiffness of the panel, while also using less material because the plastic does not have to be drawn so deeply into the mold in the short portions.