Abstract: A foam-plastic core for a structural laminate produced by converting standard, rectangular slabs of closed-cell, rigid foam plastic stock in which the density of each slab varies from the inner to the outer regions thereof into relatively thin panels useable as the core of a structural laminate in which the core is sandwiched between facing sheets. To produce these cores, several standard slabs are stacked and bonded together by parallel lines of adhesive compatible with the foam plastic material to create a large multi-slab block. The block is then sliced transversely in parallel planes normal to the lines of adhesive to yield a plurality of panels. Each panel is composed of a series of interconnected foam-plastic sections derived from respective slabs of the block whereby the density of the sections is evenly distributed throughout the panel and the mechanical properites of the panel are therefore predictable and satisfy structural laminate criteria.

Abstract: A structural laminate in which an end-grain balsa core panel is sandwiched between and adhered to facing skins that cover the edges of the panel as well as its opposing faces. To make it possible for facing skins that cannot be sharply bent to conform to edges of the panel, these edges are bevelled to impart a gentle slope thereto. Bevelling is effected by means of a high-pressure die whose angled face has a staircase formation defined by a series of right-angle microsteps. When the die is forced against a right angle edge of the core panel to be bevelled with a pressure exceeding the compressive strength of the balsa, each microstep then impose pressure in a direction parallel to the axes of the cluster of internal balsa cells engaged by the microstep to more or less collapse this cluster to an extent depending on the staircase position of the microstep, thereby densifying the internal structure of the balsa at the edge of the panel without disintegrating this structure.

Abstract: A light-weight, high-strength contourable core for inclusion in a contoured structural laminate in which the core is sandwiched between facing skins. The core is constituted by a planar array of block-like modules preferably made of end-grain balsa wood held together in edge-to-edge relation by a scrim formed by elastomeric filaments which extend through the body of the modules in an intermediate plane parallel to the opposing faces of the core. When the planar core is pressed against a wet-coated contoured skin surface for lamination thereto, the filaments bridging adjacent modules elongate to an extent permitting these modules to separate and conform to this surface. The filaments have an elastic recovery force low enough to prevent the modules from overcoming the surface tension created by the wet-coated surface and pulling away therefrom. However, the holding power of the filaments is sufficient to preclude disassembly of the core modules during normal core handling procedures.

Abstract: A contoured structural laminate formed of thin facings bonded to an end-grain balsa wood core. The laminate is produced by first bonding a liner of end-grain balsa to each facing to create front and rear plies. The exposed surfaces of the liners are then wet coated with a bonding solution, and the two plies with their coated liners in face-to-face relation are placed in a forming press which causes the front ply to assume a concave-like formation and the rear ply a complementary convex-like formation. During forming, the wet interface of the liners affords slip freedom. When the bonding agent dries and cures in the press, the plies are permanently laminated together to form the desired contoured structure.

Abstract: A structural sandwich laminate constituted by thin skins, such as aluminum or fiber-reinforced plastic sheets bonded to the faces of a core formed by an array of wood strips having a periodic wave formation. The wavy strips in the array are out of phase with each other and are bonded together at their contiguous troughs and peaks to define an open-celled expanded wood structure whereby the laminate, though light-weight, has high strength.

Abstract: A high yield technique to convert normally-unusable round logs of balsa or other species of wood whose diameter is less than about 4 inches into large rectangular panels that are contourable.The raw logs are first peeled to expose the wood and are then cut into round pieces of a desired length. The pieces, after being kiln-dried, are stacked to form a dry assembly in which the pieces are separated from each other to define a matrix of intersticial spaces. The pieces in the assembly are then interlaminated in a mold by filling the matrix with an elastomeric plastic solution which, when cured, functions as an adhesive to provide an integrated stock block. The stock block is then divided into panels of the desired thickness, each panel being constituted by an array of round wood tiles joined together by elastomeric hinges, whereby the resultant panel is contourable and may be conformed to a curved surface.

Abstract: A structural sandwich laminate formed of thin facings, such as aluminum or fiberglass sheets, bonded to a core panel. The core panel is formed of end-grain balsa wood having an array of holes punched therein, the holes having their centers on the apexes of a diamond, thereby making possible a high concentration of holes with an adequate separation therebetween to define a reticulated balsa core of high strength and exceptionally light weight.

Abstract: A high yield technique for converting round logs of balsa or other species of wood of relatively small diameter into large rectangular panels, the percentage of log volume that is converted being substantially greater than with prior techniques. The logs are radially sectioned into sectors having the same apex angle. Each sector is then longitudinally cut at its apex and arc to define a truncated feedstock piece whose cross-section is that of an isosceles trapezoid, the feedstock pieces being of variable width depending on the diameters of the logs from which they are derived. The pieces are fitted together in a complementary manner to create uniform layers which are superposed to form a stack defining a dry block assembly. The end pieces in each layer are constituted by feedstock piece halves to present a vertical block edge. All feedstock pieces in the dry block assembly are then wet-coated with a curable adhesive.

Abstract: A high-yield technique for converting logs of balsa having a small diameter into large rectangular panels. Each log is longitudinally cut into raw pieces, all of whose broad faces lie in a plane parallel to a tangent to the curvature of the log. The cuts are spaced to produce a pair of opposing side pieces having like thicknesses and at least one center piece. The uncut surfaces of the side pieces are faceted to provide stock pieces having a trapezoidal cross-section, whereas the uncut surfaces of the center piece are faceted to provide a stock piece having a rectangular cross-section. The stock pieces thus formed are fitted together in a complementary manner to create uniform layers thereof which are stacked to define a dry block. The pieces in the dry block are then wet-coated with a curable adhesive and reassembled to form a wet block which is subjected to compression until the adhesive is cured and the stock pieces interlaminated to form an integrated block.

Abstract: A set of hinged covers adapted to sealably close the rectangular hatch on the roof of a railway hopper car having a coaming running along the hatch perimeter. Each cover has a vaulted formation to shed water, the long edges of the cover being rolled to define canopies which protectively shield the coaming and a compressible gasket secured to the underside of the cover which presses against the coaming to effect a seal against contaminants. The cover structure is a sandwich laminate of high rigidity and strength constituted by an end grain balsa wood core panel to whose faces are bonded fiberglass skins. The skins are extended beyond the ends of the panel and are interlaminated to define channel-shaped end flanges which cooperate with hinged hold-down bars having an opposed channel formation within which a compressible gasket is nested to seal the ends of the cover.

Abstract: A double-tank shipping container for general bulk liquid cargo, the container being constituted by a sea-going vessel having a single hull provided with a hold which defines the outer tank of the container and a prefabricated flexible bladder forming an inner tank received within the outer tank and readily removable therefrom. The inner tank has a configuration roughly conforming to the contours of the outer tank and yet capable of sustaining the liquid cargo in the event of a rupture in the outer tank, thereby to prevent spillage from the vessel and to avoid pollution of the seas.

Abstract: A high yield technique for converting normally-unusable round logs of balsa or other species of wood whose diameter is less than about 4 inches into large rectangular panels. The raw logs are first peeled to expose the wood and are then cut into round pieces of a desired length. The pieces, after being kiln dried, are assembled into a block, the pieces being coated with a curable adhesive and being subjected to compression in orthogonal directions until the adhesive is cured and the pieces interlaminated to provide an integrated stock block. The stock block is then divided into panels of the desired thickness and grain direction.

Abstract: A high-yield, low-cost technique for converting balsa wood logs into thin, flat sheets usable in model-making. In this technique, the log is first debarked and then cut to a standard bolt length. The bolt is supported for rotation in a veneer lathe which acts to peel off in spiral form a continuous web of balsa veneer. After kiln drying, dried sheets taken from this web are clipped to a usable width, the sheets at this point having a curvature as a result of their spiral memory. Then the sheets are assembled into matching pairs of opposing curvatures, each pair of sheets being laminated together in face-to-face relation to produce a two-ply flat sheet whose planarity, upon exposure, is immune to changes in relative humidity and temperature.

Abstract: A high yield technique for converting round logs of balsa or other species of wood of relatively small diameter into large rectangular panels, the percentage of log volume that is converted being substantially greater than with prior techniques. The logs are radially sectioned into sectors having the same apex angle. Each sector is then longitudinally cut at its apex and arc to define a truncated feedstock piece whose cross-section is that of an isosceles trapezoid, the feedstock pieces being of variable width depending on the diameters of the logs from which they are derived. The pieces are fitted together in a complementary manner to create uniform layers which are superposed to form a stack defining a dry block assembly. The end pieces in each layer are constituted by feedstock piece halves to present a vertical block edge. All feedstock pieces in the dry block assembly are then wet-coated with a curable adhesive.

Abstract: A cryogenic container adapted to store or transport liquified gases, the container including an outer tank formed by walls which have thermal insulation properties and are structurally capable of supporting the load, the walls incorporating a liquid and gas-impervious secondary barrier. Received within the outer tank and readily removable therefrom is a prefabricated independent inner tank constituted by a flexible bladder whose geometry roughly conforms to the contours of the inner surface of the outer tank. The bladder is formed of a synthetic plastic fabric material that is coated to render it liquid and gas-impervious to define a primary barrier, which coated fabric material maintains its flexibility and other physical characteristics at cryogenic temperatures and has sufficient structural strength to sustain the cryogenic liquid load without any danger of rupture even in those areas thereof in which the bladder does not fully conform to the contour of the outer tank surface and is not backed thereby.