Paper-based elongate structures suitable for use as lumber substitutes, articles of manufacture made thereof, kits of materials including such structures, and machines and methods for making the same. Elongate structures according to the invention include a hollow outer portion formed of corrugated fiberboard sheet material and an accordion-folded inner support formed of corrugated fiberboard sheet material. The hollow outer portion has four outer surfaces that define a rectangle when viewed in cross-section transverse to a longitudinal axis of the elongate structure. The accordion-folded inner support is enclosed within the hollow outer portion. The inner support includes a plurality of first spaced-apart peaks that contact a first inner surface of the hollow outer portion and a plurality of second spaced-apart peaks that contact an opposing second inner surface of the hollow outer portion. The accordion-folded inner support structure improves the beam strength, crush resistance and lateral strength of the elongate structure.

An apparatus is provided for producing longitudinally corrugated product. The apparatus includes a guide roll for guiding a web of medium material, wherein at least a portion of the guide roll is adapted to be arranged at an angle relative to another portion of the guide roll. The apparatus further includes a plurality of flute forming bars oriented generally along a longitudinal axis of the web to define a first corrugating labyrinth effective to longitudinally corrugate the web to an intermediate geometry. The apparatus further includes a pair of corrugating rollers that cooperate to define, at a nip therebetween, a second corrugating labyrinth effective to longitudinally corrugate the web to a substantially final geometry. The apparatus further includes a web travel pathway for the web that follows a path around a portion of the guide roll, through the first corrugating labyrinth, and through the second corrugating labyrinth.

A system and method for producing a board product made from paper products that have embossed medium that features an improved structural profile. The improved structural profile may include a triangular flute pattern wherein each flute may exhibit a first linear leg support and a second linear leg support that each support a center apex structure. The apex may have a substantially flat portion that is configured to engage a facing. As such, the board product may further include one or more facings that are adhesively coupled to the embossed medium. Further, the apex of each “triangle” may also have a groove or channel for receiving an adhesive in a continuous and uniform manner.

An apparatus for introducing transverse trapezoidal corrugations into a traveling web is provided, and includes a plurality of corrugating rollers for imparting corrugations to the web. In disclosed embodiments four such rollers are provided in a roller train defining respective first, second and third nips therebetween, wherein the teeth of the first and second rollers have rounded distal faces and those of the third and fourth rollers have flattened distal faces. Methods of yielding a trapezoidal corrugated web also are disclosed.

An apparatus for introducing transverse trapezoidal corrugations into a traveling web is provided, and includes a plurality of corrugating rollers for imparting corrugations to the web. In disclosed embodiments four such rollers are provided in a roller train defining respective first, second and third nips therebetween, wherein the teeth of the first and second rollers have rounded distal faces and those of the third and fourth rollers have flattened distal faces. Methods of yielding a trapezoidal corrugated web also are disclosed.

An apparatus is provided for producing longitudinally corrugated product. The apparatus includes a guide roll for guiding a web of medium material, wherein at least a portion of the guide roll is adapted to be arranged at an angle relative to another portion of the guide roll. The apparatus further includes a plurality of flute forming bars oriented generally along a longitudinal axis of the web to define a first corrugating labyrinth effective to longitudinally corrugate the web to an intermediate geometry. The apparatus further includes a pair of corrugating rollers that cooperate to define, at a nip therebetween, a second corrugating labyrinth effective to longitudinally corrugate the web to a substantially final geometry. The apparatus further includes a web travel pathway for the web that follows a path around a portion of the guide roll, through the first corrugating labyrinth, and through the second corrugating labyrinth.

An apparatus for introducing transverse trapezoidal corrugations into a traveling web is provided, and includes a plurality of corrugating rollers for imparting corrugations to the web. In disclosed embodiments four such rollers are provided in a roller train defining respective first, second and third nips therebetween, wherein the teeth of the first and second rollers have rounded distal faces and those of the third and fourth rollers have flattened distal faces. Methods of yielding a trapezoidal corrugated web also are disclosed.

An apparatus is provided for producing longitudinally corrugated product. The apparatus includes a guide roll for guiding a web of medium material, wherein at least a portion of the guide roll is adapted to be arranged at an angle relative to another portion of the guide roll. The apparatus further includes a plurality of flute forming bars oriented generally along a longitudinal axis of the web to define a first corrugating labyrinth effective to longitudinally corrugate the web to an intermediate geometry. The apparatus further includes a pair of corrugating rollers that cooperate to define, at a nip therebetween, a second corrugating labyrinth effective to longitudinally corrugate the web to a substantially final geometry. The apparatus further includes a web travel pathway for the web that follows a path around a portion of the guide roll, through the first corrugating labyrinth, and through the second corrugating labyrinth.

An apparatus is provided for producing longitudinally corrugated product. The apparatus includes a guide roll for guiding a web of medium material, wherein at least a portion of the guide roll is adapted to be arranged at an angle relative to another portion of the guide roll. The apparatus further includes a plurality of flute forming bars oriented generally along a longitudinal axis of the web to define a first corrugating labyrinth effective to longitudinally corrugate the web to an intermediate geometry. The apparatus further includes a pair of corrugating rollers that cooperate to define, at a nip therebetween, a second corrugating labyrinth effective to longitudinally corrugate the web to a substantially final geometry. The apparatus further includes a web travel pathway for the web that follows a path around a portion of the guide roll, through the first corrugating labyrinth, and through the second corrugating labyrinth.

A multilayer product made of paper-like material, includes at least one corrugated layer bonded to a first flat layer of cannet?. A least one corrugated layer is constituted by a sheet of cannet? which is shaped so as to form a wave. A method is also related for providing a multilayer product made of the paper-like material.