Abstract: An improved core structure is provided for composite structures and particularly those employing fiberglass reinforced plastic surface layers. In accordance with this invention, a composite article is formed having a central layer comprised of a plurality of elongated hollow rod like members which are supported by a retaining material. The rod members are preferably made from a naturally occurring hollow material such as bamboo stalks. The retaining material is preferably a foam type plastic such as urethane, PVC, or syntactic foam. The core structure may be fabricated by loading a plurality of bamboo stalks into an elongated trough form, and then filling the trough with retaining material. Following curing, the core body is removed from the form and is sliced into plate shaped individual core pieces. The core structures are thereafter skinned with a plastic outer layer such as fiber reinforced plastic and used to develop webs, bulkheads, reinforcing members and various other features in composite structures.

Abstract: A body having a large number of protrusions is aligned with a honeycomb surface having a greater number of openings, selected openings being engaged by the protrusions when the body is aligned, by positioning the body against the honeycomb surface and vibrating it until the protrusions engage. The method is of particular use in aligning flexible masks to end faces of honeycomb structures in the fabrication of solid particulate filter bodies. Particular mask and honeycomb structure geometries are suggested for automation of the process.

Abstract: The invention is a flexible mask for use in charging a flowable material into selected cells of a honeycomb structure and is of particular utility in charging a sealing material into the ends of selected cells of such a structure during fabrication of solid particulate filter bodies and other selectively plugged honeycomb structures. The mask has a central body with a set of openings extending therethrough which allow passage of the flowable material through to the selected cells and a second set of protrusions extending from one of the surfaces of the mask which are used to align the mask to the end face of the structure and which extend into and sealably cover the cells which are not to receive the flowable material. The mask may be formed from a polymer, preferably an elastomer, using any of three disclosed die apparatuses.

Abstract: A composite cover having high load-bearing capacity comprising an upper and a lower skin of fiber-reinforced plastic material, the upper and lower skins being integral with one another around the edges of the cover and spaced apart from one another therebetween, the space so formed containing reinforcing walls of fiber-reinforced plastic material extending between the upper and lower skins, the reinforcing walls being integral with the upper and lower skins where they contact the same, the voids between the reinforcing walls being filled with lightweight infills, and the skins and reinforcing walls being resin impregnated so as to form one solid integral unit substantially free of joints or seams.

Abstract: A composite structure having a high stiffness to weight ratio includes a substrate, e.g. graphite, defining at least a pair of outer surfaces which are spaced from each other and having a volume or void passages extending through the substrate between the outer surfaces. At least one stiffening element extends between the outer surfaces within this volume. The stiffening element defines a volume and has at least one wall intersecting each of the outer surfaces. The stiffening element and the outer surfaces are made up of a chemically vapor deposited material having the desired high stiffness to weight ratio and being formed as a monolithic structure having a thickness of at least about 1 millimeter. These structures have such diverse uses as aircraft parts and skis.

Abstract: A method of fabricating a honeycomb core sandwich structure with an embedded fastener and the resulting structure are disclosed. The method comprises laying down a first nonmetallic synthetic layer (11), preferably a graphite epoxy layer, which may be cured or uncured. Bonded to the first nonmetallic synthetic layer is a honeycomb core layer (15) into which one or more flush head fasteners (25) have been inserted. The flush head fasteners are inserted into holes (13) in the honeycomb core that have an indentation (19) at one end that is configured to mate with the underside (21) of the head (23) of a flush head fastener (25).

Abstract: Aircraft composite components having foam cores comprising at least two foam sheets joined with a sheet of honeycomb to form a foam-honeycomb-foam sandwich. The layers of sheet foam are in contact with each other and the honeycomb cells extend a substantially equal depth into and generally perpendicular to the sheet foam layers. The composite component has increased shear strength. The aircraft composite component can be made by aligning a layer of honeycomb between and generally perpendicular to two layers of sheet foam. A compressive force is applied generally perpendicular to at least one layer of sheet foam so that the honeycomb cells penetrate each of the two layers of sheet foam to a substantially equal depth so that the layers of foam contact each other to form a foam-honeycomb-foam sandwich. The foam core is surrounded by resin impregnated fibers and cured.

Abstract: A composite cover 10 for a manhole or other opening comprises an upper 12 and lower 14 skin of glass reinforced plastics material. The upper and lower skins are bonded to one another about the edges 18 and spaced apart from one another therebetween to define a space 16 containing reinforcing walls 20 extending between the upper 12 and lower 14 skins. The reinforcing walls 20 are preferably formed from a corrugated sheet of glass fibre reinforced plastics material. The cover of the invention is as strong as conventional cast iron covers but is lighter and cheaper to manufacture.

Abstract: A magnetic display panel in which syneresis is completely eliminated between a colorant and a dispersion medium by the simultaneous use of organic and inorganic thickener. A liquid sealing space is provided between two substrates sealed by an adhesive in which space a dispersing liquid having a yield value of at least 5 dyne/cm.sup.2 is filled. The dispersing liquid is composed of fine magnetic particles, a colorant, a dispersion medium and the organic and inorganic thickeners. The organic thickener is preferably one of olefinic polymer, olefinic copolymer, wax, metal soap and dextrin fatty acid ester while inorganic thickener is preferably one of fine powder silicic acid and fine powder silicate.

Abstract: A reinforced composite structure is disclosed comprising a heat resistant chemically-bonded layer of a ceramic composition mechanically attached to a metallic substrate. The structure includes a metallic anchoring matrix characterized by a plurality of spatially and cooperably arranged reinforcing elements, the matrix being attached to the substrate and projecting from the surface thereof with the spatially arranged reinforcing elements of the matrix collectively defining a ceramic-occupiable zone of finite thickness adjacent to and following the surface configuration of said substrate, the zone having at least confined therein the heat resistant chemically-bonded ceramic in intimate contact with the reinforcing elements. A method for fabricating said composite structure is also disclosed.

Abstract: A sliding roof for motor vehicles having a transparent rigid sliding cover by means of which an opening in the roof can be selectively closed or can be exposed at least partially. A frameless sliding inside cover lining is provided that can be displaced at least in the cover sliding direction independently from the sliding cover and is guided at its lateral edges. The sliding inside cover lining is formed of a sandwich panel having a core layer and a cover layer that is applied to said core layer at least on one side. In the area of its lateral edges, the sandwich panel is squeezed together reducing the core thickness and increasing its density to form sliding guide edges.

Abstract: The beam of composite material is of the type comprising two longitudinally extending outer parallel chords interconnected by webs which are parallel to one another and perpendicular to the chords, spaces between the webs being filled with a resin foam material forming a core (8, 9). The beam further comprises prefabricated box structures (2, 14) providing a connection between the chords (6) and the core (8, 9) on each side of the webs (7), and thin metal bands disposed between two thin sheets of resin-impregnated fibers constituting heating elements (10) incorporated in the core (8, 9) in intermediate parts of the latter and disposed parallel to the webs (7) and located between the latter.

Abstract: In a sandwich component, in particular for hoods, deck lids or the like, for the bodywork of a motor vehicle, comprising a core layer interposed between covering layers and a reinforcement member adjacent which the core layer is recessed and which is joined to the covering layers and the core layer by means of plastic foam, the reinforcement member being made dish-shaped and provided with a base having openings and with a projecting flange having openings, and the flange being adjacent to one covering layer from the inside and the base being adjacent to the other covering layer from the inside.

Abstract: A self-supporting composite plate for double floors, ceilings or the like, with a pan-shaped outside wrapper member and a hardenable mineral filler, e.g., anhydrite, which can be introduced in liquid state into the pan-shaped wrapper member, and in which are embedded lightweight construction materials. The construction materials are substantially spherical bodies that are retained in a predetermined distribution essentially in the area of the statically neutral zone of the composite plate by a latticed holder that is provided within the wrapper member.

Abstract: Disclosed is a manner of making a core by shearing and bending a strip (36) of sheet metal into ribbons. The ribbons thereby constitute a series of troughs (53) and crests (52). The core is sandwiched between two skins (64,65). The crest and troughs are presented as tubes (66) extending into the interior of the core from an edge of the panel. Polyurethane foam is injected into these tubes. The foam rises and sticks the cores to the skins. The resulting panel is strong, rigid, durable, inexpensive, and extremely versatile.

Abstract: This invention is directed to means for expediting the fabrication of selectively-manifolded honeycomb structures for use as fluid filter elements. The method comprises the use of flexible masks which are properly aligned to the end faces of a honeycomb structure utilizing vibratory motion in conjunction with a locating wire. By varying the configuration of the masks, it is possible to fabricate a fluid filter element having a center zone which is selectively manifolded and an outer portion wherein at least the ends of the honeycomb structure cells are completely filled.

Abstract: A self-supporting board enjoying very good heat insulation and fire-resistant properties is obtained by combining a reinforced plastics foam 2 with insulating boards 3, 4 of expanded perlite. The foam is reinforced by a framework 5 consisting of latticed beams 11 covered by metal meshes 8, 10.

Abstract: Handleable and machineable shapes of thermal insulation material are made by compacting finely divided thermal insulation material into the cells of a reinforcing honeycomb structure.The finely divided thermal insulation material may be, for example, silica aerogel, pyrogenic silica, carbon black, silica gel, volatilized silica, calcium silicate, vermiculite or perlite, or finely divided metal oxides such as alumina or titania. The finely divided thermal insulation material may include an infra-red opacifier and/or reinforcing fibres.The reinforcing honeycomb structure may be made from, for example, metals such as aluminium foil, inorganic materials such as ceramics, organic materials such as plastics materials, woven fabrics or paper. A rigidiser may be employed.The shapes of thermal insulation material are substantially rigid and may be machined, for example, by mechanical or laser cutting devices, or may be formed, for example by rolling, into curved or other shaped materials.

Abstract: A method of producing a unitary curved structure having a honeycomb core by coating a mold with gel, applying a layer of reinforced fiberglass plastic to the gel to receive, after partial curing, a light layer of chopped glass fibers (about 3/4 ounces/sq. ft.) and a mixture of catalyzed resin and chopped fiber strand. The resulting surface may be rolled to remove bubbles and oversprayed with catalyzed resin. A Raw Kraft paper honeycomb is placed into the wet laminate and completely covered with wax paper weighted with sand bags to approximately 10 pounds per square foot to press the honeycomb into place and seal same. The resin is absorbed in and climbs the honeycomb walls, and heat and styrene gas are liberated into the cells. The bags and wax paper are removed after partial cure, excess styrene fumes are blown away, and the honeycomb is lightly oversprayed with a catalyzed resin.

Abstract: A method of producing a mask to be used for the production of a ceramic filter is disclosed, wherein an ultraviolet ray-transmitting film, which cannot transmit ultraviolet ray at the portion corresponding to the through holes of a porous ceramic honeycomb structural body, into which holes a sealing material is to be injected at the opening end surface of the body, and can transmit ultraviolet ray at the portion corresponding to the through holes of the body, into which holes the sealing material is not to be injected at the opening end surface of the body, is made; the film is arranged on an ultraviolet ray-curable resin; ultraviolet ray is irradiated to the resin through the film; and the ultraviolet ray-uncured resin portion is removed from the resin. The mask matches to the porous honeycomb structural body, and a ceramic filter can be easily produced from the body.

Abstract: The disclosed method seals preselected open ends of channels of a ceramic honeycomb structural body by attaching a film to that end surface of the honeycomb structural body which is to be selectively sealed while boring holes on the film at positions corresponding to desired open ends of the channels to be sealed, dipping the end surface in a sealing material containing slurry, pressing sealing material mixture body in the desired channels open ends, and then firing the ceramic honeycomb structural body with the sealing materials applied thereto.

Abstract: Improved masking apparatus and methods for bulk charging a flowable material into selected cell ends exposed at an end face of a honeycomb structure. The masking apparatus utilize protrusions which assist in properly aligning the apparatus to the end face and reduce the possibility of improperly charging cells. In one apparatus embodiment, a planar body is provided having a plurality of hollow protrusions which extend into selected cell ends when the planar body is fitted against an end face of the structure. A flowable material charged against the planar body passes through the hollow protrusions into the selected cell ends. In another embodiment, a plurality of preformed protrusions or plugs are mounted along thin, flexible members at predetermined locations. The plugs are removably inserted into and temporarily block or cover the ends of an equal plurality of cells. A flowable material charged against the end face passes into the remaining, uncovered cells.

Abstract: A composite, lightweight, fire-retardant laminar structural panel (10, 10', 10", 30) of the present invention comprising: (i) a sheet-like central honeycomb core (11) formed of aluminum, paper treated to improve its fire resistance characteristics, or the like; (ii) upper and lower imperforate face sheets (15, 16) formed of lightweight fibrous materials impregnated with a phenolic resin; (iii) a pair of upper and lower phenolic adhesive films (18, 19) interposed between the honeycomb core (11) and respective ones of the imperforate face sheets (15, 16) for adhesively bonding the face sheets (15, 16) to opposite sides of the core (11); and (iv), a fire-retardant coating (20) comprising a copolymer of vinylidene fluoride and hexafluoropropene applied to at least the exposed surface of the lower face sheet (16).

Abstract: A magnetic display panel having a transparent or translucent front substrate and a rear substrate bonded thereto by an adhesive with a dispersing liquid confining space formed between the substrates, preferably in the form of multiple cells. The dispersing liquid, composed of a fine particulate thickener, fine magnetic particles, a colorant and a dispersing medium, has a yield value of at least 5 dyne/cm.sup.2. A clear, long-lasting image is recordable by tracing a permanent magnet upon the face of the first substrate.

Abstract: The invention relates to a semi-finished product based on fibers preimpregnated with polymerizable resin, which is intended for the manufacture of components made of composite materials and having a variety of shapes, in particular long and/or thick components. This semi-finished product comprises at least one layer formed of a plane web of preimpregnated fabric and of a web of strips of preimpregnated rovings arranged in rows juxtaposed on the fabric in one and the same longitudinal direction. Another web of preimpregnated fabric is preferably provided. It passes alternately above and below the rows of strips. The fibers of the rovings and of the fabrics can be glass fibers, carbon fibers, boron fibers or Kevlar fibers.

Abstract: Radiation is directed toward a support through an ordered array of lateral walls to form interlaid radiation-exposed and shadowed microareas on the support. A first composition is then located on the support in either the shadowed or unshadowed microareas. At least one additional composition is then positioned on the support in laterally displaced microareas forming an interlaid pattern with the first microareas.

Abstract: A sound damping material is disclosed, which is a composite structural body comprising honeycomb or corrugated core, plain sheet and pressure sensitive adhesive layer, a height direction of the honeycomb or corrugated core being perpendicular to a surface of a vibrating body. In this sound damping material, one pressure sensitive adhesive layer is at least existent between the honeycomb or corrugated cores or between the honeycomb or corrugated core and the plain sheet.

Abstract: A sintered, honeycomb structure having plugged cell ends is formed in a single sintering step by plugging the cell ends of a sinterable honeycomb structure with an appropriate material which, when heated to the sintering temperature of the structure and compared with any dimensional changes the structure undergoes during its sintering, provides a relative expansion of the plugs with respect to the structure of between about 1.5% and 7% and, preferably, between about 2 and 4%. Various exemplary batch mixtures are identified for fabricating solid particulate filter bodies from extruded ceramic substrates in which both the substrate and plugs sinter to primarily cordierite crystal phases at temperatures between about 1340.degree. C. and 1450.degree. C.

Abstract: This invention discloses ceramic honeycomb structural bodies having high thermal shock resistance and mechanical strength in which partition walls forming numerous parallel channels of the honeycomb structural bodies and/or connecting portions of the partition walls are constructed so as to have flexibility. The flexibility allows thermal stress generated in the honeycomb structural bodies to be absorbed. The bodies are characterized in that a given area of outer circumferential annular portion of said ceramic honeycomb structural bodies has a structure having a higher rigidity than the inner portion.

Abstract: A connector device for interconnecting a pair of adjacent floor mats wherein the mats are of the type having a rubberized base portion with a plurality of apertures therethrough and a plurality of supporting feet which extend integrally downwardly from the base portion to maintain it in upwardly spaced relation to a supporting surface. The connector device includes a connector body and a plurality of upwardly extending connector elements which are attached to the body. The connector elements are receivable in apertures adjacent the peripheries of a pair of abutting floor mats with the connector body extending between the mats. Plugs or the like are permanently securable in the connector elements in one of the mats to permanently secure the connector device thereto.

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: Improved masking apparatus and methods for bulk charging a flowable material into selected cell ends exposed at an end face of a honeycomb structure. The masking apparatus utilize protrusions which assist in properly aligning the apparatus to the end face and reduce the possibility of improperly charging cells. In one apparatus embodiment, a planar body is provided having a plurality of hollow protrusions which extend into selected cell ends when the planar body is fitted against an end face of the structure. A flowable material charged against the planar body passes through the hollow protrusions into the selected cell ends. In another embodiment, a plurality of preformed protrusions or plugs are mounted along thin, flexible members at predetermined locations. The plugs are inserted into and block or cover the ends of an equal plurality of cells. A flowable material charged against the end face passes into the remaining, uncovered cells.

Abstract: Two sheets of reflective plastic film included in the construction of a fiber-insulated thermal garment mitigate radiated heat loss while retaining the conventional insulating properties of fibers. A layer of porous matted fibers separates the two layers of reflective sheets, holding them apart and allowing a free passage of air between. The plastic sheets are provided with venting holes which allow the garment to "breathe" and prevent moisture accumulation. The venting holes in opposing plastic sheets do not align but rather are offset, forcing warm air passing through the garment to follow a zigzag route. The plastic sheets are further provided with a flat black finish on their outer-facing surfaces in order that the inside sheet may recapture radiated heat from escaping warm air and the outside sheet may absorb any ambient radiated heat, such as sunlight.

Abstract: A press, carried by a first table and having punch and die components, receives a rectangular filler sheet and forms a lateral accordian fold sheet. The accordian fold sheet is lifted from the press by transfer means and placed upon an envelope sheet overlaying a second table. Hinged panels carried by the second table fold the envelope sheet over the accordian fold sheet, forming a rigid compartmentalized panel having an opening along a longitudinal edge. The second table, with the opening upright, moves to a position under a receptacle from which granular loose fill material is entered into the compartments through the opening. Subsequently, flaps extending along the panels move to further fold the envelope sheet and close the opening.

Abstract: An absorbent pad is provided for use in a receptacle intended to contain and display food products which tend to exude juices or liquids. The absorbent pad comprises a mat of liquid absorbent material, an upper liquid impermeable plastic sheet overlying the absorbent mat, and a bottom plastic sheet underlying the absorbent mat. At least one of the sheets is perforated, and spacer means is disposed between the two sheets to maintain their separation under a compressive load, and such that the ability of the pad to absorb liquids is unimpaired when the pad is subjected to a compressive load resulting from the food product resting thereon or the like.

Abstract: Honeycomb structures, such as those used in turbine engine abradable seals, are provided with a uniform density filling of a suitable abradable material. The abradable material is prepared as a tape preform using an organic binder. The preform is forced into the honeycomb using a rubber tool.

Abstract: A flexible mask, used to plug with a cement material alternate passages in a honeycomb matrix structure whereby it can be used as a diesel particulate filter, has a base with spaced apart pins extending therefrom to fit into alternate cells of the honeycomb matrix, the base being provided with through apertures positioned intermediate adjacent associate pins for alignment with the other cells through which the cement material can be forced to plug the end of these cell openings.

Abstract: Photographic elements, multicolor filters and receivers are disclosed having supports providing microvessels for materials such as radiation-sensitive materials, imaging materials, mordants, silver precipitating agents and materials which are useful in conjunction with these materials. Processes of forming microvessels and introducing materials therein are also disclosed. Processes of forming images are disclosed employing microvessel containing elements. Image transfer processes are disclosed for producing one or a combination of silver and multicolor subtractive primary images alone or in combination with multicolor additive primary images.

Abstract: In the forming of microcellular arrays, such as those useful in photography, a closure is positioned to overlie a plurality of microcells forming a planar array. The closure is selectively removed from one set of micro- cells forming an interlaid pattern with a second set of microcells so that the contents of the first set of micro- cells can be changed without concurrently changing the contents of the second set of microcells.

Abstract: A method of joining together two composite honeycomb panels each having internal cellular structure wherein related bores are formed in the respective panels with at least one of said bores extending entirely through its panel, the panels are placed in tightly abutting relation with the bores in alignment, a hollow tubular fastener is inserted through the one bore to project into and along the aligned bores, and fluent anchoring glue type adhesive is forced into the fastener so that some of the adhesive extrudes from within the fastener through side apertures to randomly occupy adjacent space in the cellular structures of both panels, and the anchoring adhesive is hardened in situ; and the resultant coupled panel assembly.

Abstract: Photographic elements, multicolor filters and receivers are disclosed having supports providing microvessels for materials such as radiation-sensitive materials, imaging materials, mordants, silver precipitating agents and materials which are useful in conjunction with these materials. Processes of forming microvessels and introducing materials therein are also disclosed. Processes of forming images are disclosed employing microvessel containing elements. Image transfer processes are disclosed for producing one or a combination of silver and multicolor subtractive primary images alone or in combination with multicolor additive primary images.

Abstract: An absorbent article comprising a cover sheet and a backing sheet, the cover and backing sheets being attached in areas without the use of water-insoluble adhesives to form pockets in which a fluid absorbent material is stored. The absorbent article is formed by depositing portions of the fluid absorbent material on the backing sheet, placing the cover sheet over the absorbent material and the backing sheet, and pressing the cover sheet towards the exposed parts of the backing sheet to cause bonding of the fibers in each sheet and attaching the cover sheet to the backing sheet to form pockets in which the absorbent material is stored.

Abstract: A method for preparing a resistive screen for underwater sound absorption consisting of a metallic honeycomb structure, adding a thermosetting plastic material to the cells within said structure, heating said structure under pressure and forming small apertures within said thermosetting plastic material.

Abstract: The disclosed ceramic honeycomb filter comprises a ceramic honeycomb structural body with a multiplicity of parallel channels extending therethrough, selected channels being sealed at one ends thereof by sealing material while the remainder of the channels being sealed at opposite ends thereof by said sealing material in such a manner that, as dust-containing gas flows therethrough from said one ends to said opposite ends, the gas passes through walls between adjacent channels where the dust particles are collected. Said sealing material is alumina cement containing not more than 27% by weight of calcium oxide (CaO), or a mixture of the alumina cement and aggregates.

Abstract: A mechanical method of case bonding a solid propellant to a rocket motor e wherein a coating of a liner material is first applied to the internal surface of a rocket motor case. While the liner material is uncured a mechanical structural material selected from wire grid, wire hooks, rubber spikes, steel wool, metal grid, polyamide material, or polypropylene material is embedded in the liner material but allowed to protrude above the liner material. The liner material is allowed to cure, and an uncured propellant composition is cast against the cured liner and allowed to flow around the protruding mechanical structural material. On curing, the propellant composition attaches itself to both the liner and the mechanical structural material. The combination of the liner material, the mechanical reinforcing material, and the propellant composition provides a mechanical reinforcement in the propellant which is held in place with improved tensile adhesion against the rocket motor case wall.

Abstract: A structural material formed of a fiber and honeycomb reinforced foamed resin is disclosed, which is constructed by arranging a honeycomb material, the voids of which contain a foamable thermosetting resinous liquid, between two fibrous layers and heating the assembly to foam the resinous liquid and simultaneously cover and impregnate the fibrous layers whereby the fibrous layers and the honeycomb material are completely impregnated with and encased in the foamed resin.

Abstract: A receptacle is provided for containing and displaying food products which tend to exude juices or liquids, and which comprises a supporting member, such as a tray or bag, and an absorbent pad associated therewith. The absorbent pad comprises a mat of liquid absorbent material, an upper liquid impermeable plastic sheet overlying the absorbent mat, and a bottom plastic sheet underlying the absorbent mat. At least one of the sheets is perforated, and spacer means is disposed between the two sheets to maintain their separation under a compressive load, and such that the ability of the pad to absorb liquids is unimpaired when the pad is subjected to a compressive load resulting from the food product resting thereon or the like.

Abstract: A thermal barrier comprising a heat responsive intumescent insulating matal partially filling open cells in a layer of fire retardant honeycomb material. The thermal barrier is adhesively bonded to the inner surface of an aircraft skin panel. The intumescent material is in thermal contact with the skin and expands in response to heat conducted through the skin. The intumescent material may comprise one or more of a wide variety of matrix systems and fillers. Interior upholstery adhesively bonded to the honeycomb material completes the thermal barrier installation.

Abstract: Disclosed is a method for delineating zones on the surface of thermoplastic gratings. The method comprises inserting in the grate openings a removable closure member adapted to interlock with the grating and close the opening. The removable closure member is distinguishable from the grating in color and when a plurality of closure members are so inserted in a pattern, they delineate a given zone.

Abstract: Marginal edge portions of two spaced apart flexible sheets are folded inwardly and joined to form an envelope. A plurality of laterally extending substantially rigid panels divide the envelope into a plurality of partitioned compartments. Each panel is angularly disposed relative each adjacent panel and the panels are fixed to the envelope, thereby providing a semi-rigid structure. Fibrous insulation material, especially cellulosic material such as treated ground paper, is contained in each compartment.