Abstract: A connective protective packaging element is provided. The connective protective packaging element may include a protective body in a high-density supply configuration. The protective body may be configurable into a low-density configuration for cushioning packaged products. The body may include an exposed surface in the low-density configuration. The connective protective packaging element may also include a bonding element attached to the exposed surface that operably bonds the exposed surface to an abutting surface by contact with the bonding element.

Abstract: The embodiments herein are directed to a reusable frameless vehicle roof-top carrier configured, dimensioned and arranged to securely mount and carry cargo loads having a size and shape similar to cut evergreen trees, while protecting the vehicle finish and cargo from damage. The reusable vehicle roof-top carrier is trapezoidal shaped to conveniently bind and condense branches of the tree, while catching sap drippings. Illustratively, the vehicle roof-top carrier is made from a tear-resistant fabric and includes a non-tacky non-slip surface placed in slip-resistant contact with the roof of the vehicle so as to prevent slippage (i.e., movement) of the tree during transport.

Abstract: A sheet of material suitable for roofing or industrial wrapping applications has an anti-skid surface formed by ridges of twisted tapes. The sheet comprises a woven scrim of warp tapes and weft tapes. Some of the tapes are twisted about their longitudinal axis, for example about 25 to 400 revolutions per meter, to form ridges having a height substantially greater than the thickness of the tapes. The ridges impart an anti-skid surface to the sheet. The scrim is bonded to a coating or film to make the sheet waterproof.

Abstract: The present invention provides a multilayer body, a packaging material and a container, each of which can maintain excellent water repellent properties and non-adhesive properties. Specifically, the present invention describes a non-adhesive multilayer body wherein hydrophobic oxide fine particles having an average primary particle diameter of 3-100 nm adhere to at least a part of the outermost layer.

Abstract: A self-supporting, rigid, and collapsible reusable bag made from flexible material and having a bottom, two first sidewalls, two second sidewalls, a top opening, and rigid insert. A rigid full-wall board is embedded in each of the two first sidewalls. A rigid insert comprised of at least one pair of sidewalls and bottom with substantially similar dimensions to the second sidewalls and bottom of the bag are placed in the interior and in frictional contact with the second sidewalls and bottom of the bag. The rigid insert sidewalls are held in place with securing devices located on the interior upper corners of the sidewalls of the bag. The bag can be collapsed by moving the rigid insert away from the second sidewalls and bottom to allow the second sidewalls to fold either inward or outward. A full-wall pocket is provided for each first sidewall to receive the full-wall board.

Abstract: Pre-filled mortar packages are positioned between masonry construction elements (such as stones, blocks or bricks) when forming a wall (such as a dry-stack stone wall). Each mortar package includes an outer covering with a porous outer surface, a mortar mixture covered by the outer covering, and (optionally) an adhesive incorporated onto or in the porous outer surface. Both the adhesive and the mortar mixture are activated by a liquid, such as water. The mortar packages may be pre-wetted and placed on masonry construction elements when stacking the masonry construction elements. Alternatively, the mortar packages may be dry when placed on masonry construction elements, and activated by applying water or by wetting from rain water. Mortar packages are more convenient and efficient than adhesives or mortar alone, and create walls and other structures with increased strength and improved aesthetics.

Abstract: A container for storing and/or dispensing liquid includes a body portion having a neck portion with an opening, at least one protrusion and at least one recessed portion, so that the container can utilize internal liquid pressure to provide strength for the container, so that less material is required for supporting the shape and structure of the container and so that the use of external packaging can be avoided.

Abstract: A self-supporting, rigid, and collapsible reusable bag made from flexible material and having a bottom, two first sidewalls, two second sidewalls, a top opening, and rigid insert. A rigid full-wall board is embedded in each of the two first sidewalls. A rigid insert comprised of at least one pair of sidewalls and bottom with substantially similar dimensions to the second sidewalls and bottom of the bag are placed in the interior and in frictional contact with the second sidewalls and bottom of the bag. The rigid insert sidewalls are held in place with securing devices located on the interior upper corners of the sidewalls of the bag. The bag can be collapsed by moving the rigid insert away from the second sidewalls and bottom to allow the second sidewalls to fold either inward or outward. A full-wall pocket is provided for each first sidewall to receive the full-wall board.

Abstract: Bags for granular material with a closure on top of the bag and a vertical handle on the lower end of the bag and having suitable dimensions, static coefficient of friction, creep resistance and containing granular materials of limited flow properties can be vertically stacked without support, for example on a pallet. One such suitable granular material is cat litter.

Abstract: The fries and condiment holder is a combination of two open containers. The larger of the two open containers provides the user with a place to store a food item found at fast food restaurants such as French fries. The smaller of the two open containers is attached to the larger container by a nontoxic adhesive because the present invention makes contact with edible food. The smaller container provides the user with a place to store a condiment. The smaller container is also collapsible and can be flushed into larger container. The user obtains the present invention with the food item in the larger container and with the small container collapse. The user can choose to expand and fill the smaller container with a condiment if the user wants to dip his/her food item in the condiment.

Abstract: The present invention is a bag (1) composed of multiple removable bags (10) (9) (8) (7) (6) (5), forming a set (1) with bags disposed in layers (5). It is designed to be used especially in places that accumulate and/or collect grit/dirt, both in hydraulic plants and in isolated places, such as trash cans and temporary toilets. It is also appropriate for places where products are separated manually. It resolves the difficulties of the first steps of placement of bags end reduces the time spent on carrying out maintenance, bringing benefits both due to its lower cost and the less time of exposure to an uncomfortable body position for its users. The set (1) is set in place, and the innermost bag (10) of the set is removed after being used, taking with it its contents; after that, the place is immediately ready for use. After the first bag is used and removed, the second ,0g (9) is, and so forth, until all the bags have been used.

Abstract: A bag is disclosed having handle portions with mounting apertures and a central mounting tab having a central mounting aperture. The central mounting aperture is formed as a generally inverted “V” or triangular shaped slot with inwardly and upwardly curved lower portions. A bag pack is also disclosed formed of multiple stacked handle bags having aligned mounting apertures defined through the handle portions of the bags for reception of mounting rods therethrough. The mounting apertures are formed as elongated, generally vertically extending, slots having curved upper and lower portions. Elongated mounting slots make possible the use of shorter handles for the bags without sacrificing either the size of the mouth opening during loading or the carrying capacity of the bags.

Abstract: Bags for granular material with a closure on top of the bag and a vertical handle on the lower end of the bag and having suitable dimensions, static coefficient of friction, creep resistance and containing granular materials of limited flow properties can be vertically stacked without support, for example on a pallet. One such suitable granular material is cat litter.

Abstract: The bag may include a draw tape that may be used to cinch closed the opening of the bag. The draw tape has at least one stretched elastomeric strip attached to the draw tape in an extended condition. The draw tape may be smaller in size than the bag sidewalls. The draw tape may include an elastic characteristic, such as patterned ribs. In one embodiment, the roll of bag is kept under tension to maintain the elastomeric strips in a stretched condition.

Abstract: The invention relates to a side-folded bag (1) for use in a packaging machine made of a foil material and having a bag wall (2), a bag seam (3), at least one and preferably two side folds (6a, 6b) and a fill opening (4). The side-folded bag (1) according to the invention is characterized in that a hanger (9) made of a foil material and attached to the bag wall (2) in an adhesive fashion is provided with at least one fixing or blocking point (5a, 5b). The invention further relates to a stack comprising such bags and the use of said stack in a packaging machine and a production method for the bag.

Abstract: An improved bulk bag with an upper portion of the sidewalls that is sloped inward from vertical so that when the fabric is stretched upward in the lifting process, thereby creating tension in the vertical fabric, the tension will be maintained after the bag is no longer in a lift position, as the fabric cannot slide back down around the product due to the restricted size of the fabric and such tension provides stronger restrictions to product movement to provide increased stability.

Abstract: A bag made from a length of material (10) divided into a series of three or more substantially equal sized sections (12, 14, 16, 18, 20). Every other section is filled with sand (14, 18), or other particulate material and there is an unfilled section (12, 20) at each end.

Abstract: A flexible container and method for making same are provided. The container comprises a base portion including a bottom, side walls, and an interior, the bottom defining a substantially flat planar surface when the container houses product and the container rests on its bottom, an upper panel portion, that is designed to be received within the interior of the base portion and includes side panels that define a closure member, the upper panel being so constructed and arranged to define a substantially flat surface when the closure member is closed and portions of the upper panel are folded over, the upper panel includes a portion that is sealed to the base portion, and a pair of handles may also be coupled to the base portion.

Abstract: A flexible container (10) has a base (12) that includes a bottom (20), side walls (22, 24, 26, 28) and an interior (30), the bottom defining a substantially flat planar surface when the container houses product and the container rests thereon, an upper panel portion (14), that is adapted to be received within the interior of the base portion and includes side panels that define a closure member (60, 62). The upper panel is constructed and arranged to define a substantially flat surface (72) when the closure member is closed and portions of the upper panel are folded over. The upper panel includes a portion that is sealed to the base portion. A pair of handles (16, 18) may be secured to the base portion. The flat top and flat bottom allow for vertical stacking of the filled containers.

Abstract: A convenience package for thin film products according to aspects of the present invention places a folded stack of thin film plastic bags inside a container to protect the bags during shipping, handling and dispensing. The container surrounds the plastic bags and includes an opening through which individual bags are retrieved. The plastic bags are attached to each other in such a manner that retrieval of a first bag through the opening in the container partially retrieves a second bag and leaves part of the second bag protruding through the opening. Attachments between bags within the container ensure that each bag is opened as it is retrieved through the opening.

Abstract: A stand-up packaging pouch manufactured in three-dimensional form or flattened form and provided with at least front face portion and rear face portion sides formed from packaging material having a pleat which is formed by folding a part of the packaging material in a three-fold strip form and adhering the inner faces of this folded part is constituted such that when the pouch is opened out into three dimensions, the pleat, formed in the same plane as the peripheral face portion, is positioned at a substantial right angle to a bottom face portion, thereby concealing the bottom face portion.

Abstract: A flexible stand-up package having a releasably securable closure, a fitment pour spout and a handle. The package includes a hollow interior of the package arranged to be filled with a flowable material, e.g., cherries in syrup, whereupon the bottom of the package assumes a generally planar configuration to support the package, while portions of the panels making up the package assume a vertical orientation, with the pour spout located in a recessed position, whereupon the filled package can be located immediately adjacent similar filled packages without wasted space therebetween.

Abstract: A bulk bag includes a side wall, a bottom wall, and plurality of vertically extending pockets secured to the side wall and positioned at equally spaced locations around the periphery thereof. The pockets receive support members comprising hollow tubes which receive positioning cups at the lower ends thereof to facilitate the stacking of bulk bags one upon another. Spaced, parallel forklift tine receiving tunnels are located beneath the bottom wall and are secured either adhesively or by means of projections formed in the structure of the tunnels at spaced apart locations along the lengths thereof. The forklift tine receiving tunnels have either semicircular or inverted V-shaped cross sectional configurations.

Abstract: A manufacturing method for plastic bags recombines a layer of plastic to the outside surface of the bag to provide a portion of the outside surface with a lower melting point than the inside surface of the bag. The bags are arranged in stacks and heat is applied to bond the low melting point layer. A relatively weak bond is formed between adjacent outside bag surfaces while the bag inside surfaces remain free of each other. The weak bond is positioned along the median of the bag and near the bag opening. A second bag is drawn open by the bond during retrieval of a first bag. A flexible separation tab is arranged to maintain the separation between the inside surfaces of the open bag. The separation tab may also be made conspicuous to present an obvious retrieval point for the top bag in a hanging bag dispensing arrangement.

Abstract: A flexible container (10) has a base (12) that includes a bottom (20), side walls (22, 24, 26, 28) and an interior (30), the bottom defining a substantially flat planar surface when the container houses product and the container rests thereon, an upper panel portion (14), that is adapted to be received within the interior of the base portion and includes side panels that define a closure member (60, 62). The upper panel is constructed and arranged to define a substantially flat surface (72) when the closure member is closed and portions of the upper panel are folded over. The upper panel includes a portion that is sealed to the base portion. A pair of handles (16, 18) may be secured to the base portion. The flat top and flat bottom allow for vertical stacking of the filled containers.

Abstract: A flexible container and method for making same are provided. the container comprises a base portion including a bottom, side walls, and an interior, the bottom defining a substantially flat planar surface when the container houses product and the container rests on its bottom, an upper panel portion, that is designed to be received within the interior of the base portion and includes side panels that define a closure member, the upper panel being so constructed and arranged to define a substantially flat surface when the closure member is closed and portions of the upper panel are folded over, the upper panel includes a portion that is sealed to the base portion, and a pair of handles may also be coupled to the base portion.

Abstract: A thin-walled laminated synthetic resin body for a liquid container according to the invention comprises first and second thin-walled synthetic resin layers (10, 20), each having a curved surface portion (11, 21) and a projection (12, 22) extending outwardly from a predetermined region at an edge of the curved surface portion (11, 21). The first and second layers (10, 20) are laminated to each other with the curved surface portions (11, 21) bulging out in the same direction, are integrated with each other at the edges (13, 23) of the curved surface portions (11, 21) and projections (12, 22), and are separable from each other at regions exclusive of the edges (13, 23). When a liquid is charged, the curved surface portion (21) of one of the first and second layers (20) is separated from the curved surface portion (11) of the other layer (10) and reversed.

Abstract: A one-way outwardly gas and moisture vented, plural-layer bag for a product, such as a dry bulk product, in which bag a concealed valve is positioned near one side, and close to the originally open top, of the bag. Openings in the valve communicate with confronting openings in a gas and moisture impervious inner layer in the bag.

Abstract: A container for biological fluids useful in artificial insemination is disclosed. The inventive container has a nozzle for delivery of the biological liquid, wherein the nozzle has means for bending such that the container may be used in a vertical position while attached to a horizontal catheter. The nozzle also has means to facilitate opening the tube without tools.

Abstract: The present invention relates to a packaging bag. The packaging bag includes a bag body member. The bag body member has a double-layered structure which is formed by an inner sheet and an outer sheet, whereby toughness of the packaging bag is improved. A carrying handle member is attached to an upper end of the bag body member to enable easy carrying and handling of the packaging bag. A zipper or zippers are installed on an upper end and/or a lower end of the packaging bag, whereby the packaging bag can be rapidly and easily opened and closed.

Abstract: An engaging sandbag envelope for receiving sand or another loose bulk or free-flowing medium, wherein the specific weight of the medium is higher than that of water and it does not harden during and after filling, characterised in that hook-and-loop female connecting elements are arranged on the top surface side of the sandbag envelope and hook-and-loop male sticking elements are arranged on the underneath surface side so that when the sandbag envelopes filled with a medium are stacked one upon the other and in relationship with each other the hook-and-loop male sticking elements of the one envelope engage into the hook-and-loop female connecting elements of at least one further envelope, and in that case the hook-and-loop male sticking elements and the hook-and-loop female connecting elements on the top surface side or the underneath surface side of the envelopes are arranged over the entire surface area or in portion-wise manner.

Abstract: The present invention 10 discloses stackable bag containers 12 having opposing mating rigid planar elements 14, 15 disposed on the interior of the bags contiguous to the walls of the bag 12 having impressed therein interlocking curvilinear grooves 16, 17 extending across the rigid element 14, 15 and terminating spaced away from the periphery edge 20 of the rigid planar element 14, 15. Bag locking device 26 are provided. Embodiments utilizing corrugated walls 30, circular indentions 32 and cross line indentions are also disclosed along with an embodiment providing a sanitary storage bag for use with a conventional flowable product dispenser.

Abstract: A length of material, such as woven polyethylene, woven polypropylene, burlap, or other woven material, divided into a series of two or more substantially equal sized sections. Every other section is filled with sand, or other material. When the length of material is put in place, each row alternating a filled section and an unfilled section, a very secure, interlocking, substantially water-tight structure is formed which is much more effective in preventing the flow of water, mud or silt. Because each section is substantially square, the sections can be stacked in a parallel or transverse direction, to effect a wider and stronger structure which is substantially impervious to the flow of water, mud or silt.

Abstract: A flexible container and method for making same are provided. the container comprises a base portion including a bottom, side walls, and an interior, the bottom defining a substantially flat planar surface when the container houses product and the container rests on its bottom, an upper panel portion, that is designed to be received within the interior of the base portion and includes side panels that define a closure member, the upper panel being so constructed and arranged to define a substantially flat surface when the closure member is closed and portions of the upper panel are folded over, the upper panel includes a portion that is sealed to the base portion, and a pair of handles may also be coupled to the base portion.

Abstract: If the sandbags are used for protective walls in the case of fire or for protection against chemical substances, it is also necessary that the bags as well as the fastening and sealing devices withstand the heat of fire and chemical substances such as acids without disengagement from each other.

Abstract: A portable levee system includes a bag having a preselected geometric shape. The bag is continuous in that it has a length at least equal to its width, and is preferably many times as long. A top portion of the bag is open for receiving fill material. A preferred geometric shape is a trapezoid. The bag is removably mounted to a dispenser and the dispenser dispenses the bag from a rear portion of the dispenser. A preferred dispenser is towed behind a tractor or truck and the bag is filled within the dispenser and deposited onto the ground. A method of providing a portable levee is taught wherein a levee is created in a fraction of the time required to build an equivalently-sized levee utilizing current emergency levee construction systems.

Abstract: A set of at least three consecutive bags in a succession, each bag having two closure strips and a cursor situated at a respective distance (d1, d2) from one end of the strips, the strips and the cursor being identical between the bags. Between the bags in each pair of adjacent bags, the distances (d1, d2) are different.

Abstract: A stackable, self-supporting container comprising: (a) a semi-enclosed container body including a tubular structure having two open ends and a bottom panel enclosing one end of the container body, the other end of the tubular structure opposite from the bottom panel forming a substantially continuous outwardly-extending peripheral flange, the tubular structure including two opposed side walls, two opposed end walls between the side walls, the side walls and said end walls together forming the tubular structure, each of the end walls including a central portion and a pair of opposing supporting flaps hingedly connected to the central portion and moveable between a position substantially planar with the central portion and a position substantially perpendicular with the central portion; (b) a lid for selectively converting the semi-enclosed container to a closed container; and (c) a closure element for sealing said lid to the container body.

Abstract: Multi-walled paper sacks for powder products, notably plaster, have a porous paper inner wall surrounded by a paper outer wall and a vapour barrier separate from the paper inner wall. The vapour barrier may be a coating on the inside face of the outer paper wall. Perforations through the vapour barrier are substantially confined to either or both of the broad faces of the sack. During filling of the sacks air is able to vent through the inner wall and then through the perforations in the vapour barrier, allowing filling by high speed machinery. Deterioration of the product as a result of moisture perforation is unexpectedly just as good, and sometimes superior, to that encountered with alternative sacks. Consequently the improvement in filling is not encumbered by a reduction in shelf life of the product.

Abstract: A method of separating fluid into two or more separable fractions. One container section (2) and the adjacent portion of the other container section are made of solid material, and the two container sections are screwed together. The container sections (1 and 2) have their respective chambers (29 and 30) for receiving their respective fluid ingredients, and these chambers are interconnected through a connecting channel (31) through the abutting portions, at which the container sections (1 and 2) are screwed together. A valve seat (21, 27) is shaped at each end of the connecting channel (31) for each valve member (22, 16) for a sealing closing of the chambers (29, 30) in the separated state of the container sections (1, 2).

Abstract: A bag includes two parallel walls, each with two side edges each; a bottom connected with lower ends of the two walls and which can be folded in a plane of the walls; and two carrying handles, which in each case have two parallel legs and one cross member connecting the two parallel legs and are fastened with fastening sections, formed at their legs, in each case to one of the walls of the bag and are folded back on themselves at fold lines, so that they do not protrude beyond the walls and are detachably fixed to the bag, the cross members of the two carrying handles being offset from each other in the folded-back position by an amount, which corresponds at least to the width of the cross members and the fold lines of the two carrying handles being mutually offset by about half this amount, and the carrying handles being mutually offset in a direction perpendicular to the side edges to such an extent, that the parallel legs of the two handles do not overlap one another.

Abstract: A container for receiving and separating blood plasma into its ingredients having two sealingly coupled sections (1 and 2). One container section (2) and the adjacent portion of the other container section are made of solid material, and the two container sections are screwed together. The container sections (1 and 2) have their respective chamber (29 and 30) for receiving their respective fluid ingredients, and these chambers are interconnected through a connecting channel (31) through the abutting portions, at which the container sections (1 and 2) are screwed together. A valve seat (21, 27) is shaped at each end of the connecting channel (31) for each valve member (22, 16) for a sealing closing of the chambers (29, 30) in the separated state of the container sections (1, 2).

Abstract: A bag for packaging heavy materials, exhibiting excellent strength, content packaging performance, stacking performance on the pallets, and anti-collapsing performance. The bag is made of a multi-layer laminated film which comprises an outermost layer of a polyethylene film containing an inorganic filler in an amount of from 20 to 80% by weight and an innermost layer of a polyethylene film containing an inorganic filler in an amount of from 10 to 40% by weight, the outermost layer having on the surface thereof a coefficient of static friction of not smaller than 0.5 (ASTM D 1894), a coefficient of dynamic friction of not larger than 0.5 (ASTM D 1894) and a gloss of not larger than 50% (JIS Z 8741, at a measuring angle of 60.degree.), and the content of the inorganic filler in the innermost layer being from 1/2 to 1/6 of the content of the inorganic filler in the outermost layer.

Abstract: A modular barrier system and component bags are provided characterized by the component bags being stacked in layers and interconnected to form a retaining wall. Each bag is constructed of a woven tubular sheet that has a rectangular shape when pressed flat. One end of the bag is sealed and the other end is left open to receive sand for filling. Dual elongated straps are bonded to the lower surface of the bag and extend over the side edges. The straps are positioned at 1/5 L, 2/5 L, 1/5 L spacing to be vertically aligned for easy interconnection when the bags are stacked to form the wall. The ends of each strap are folded back to form a loop that receives the strap/loop from a bag in the layer immediately above. The loops also function as handles that allow the bags to be easily lifted and carried.

Abstract: A container for receiving and separating blood plasma into its ingredients comprises two sealingly coupled sections (1 and 2). One container section (2) and the adjacent portion of the other container section are made of solid material, and the two container sections are screwed together. The container sections (1 and 2) comprise their respective chambers (29 and 30) for receiving their respective fluid ingredients, and these chambers are interconnected through a connecting channel (31) through the abutting portions, at which the container sections (1 and 2) are screwed together. A valve seat (21, 27) is shaped at each end of the connecting channel (31) for each valve member (22, 16) for a sealing closing of the chambers (29, 30) in the separated state of the container sections (1, 2).

Abstract: The invention features a single film construction with two distinctly different surface characteristics for a trash compactor bag composite. The high slip interior layer integrally bonded to a tacky carbon outside layer forms a moisture proof, odor adsorbing trash compactor refuse receptacle. The construction may be made of biodegradable plastic.

Abstract: An extruded plastic zipper structure comprising a continuous series of predetermined length zipper sections, and hinges connecting the zipper sections together so that the sections can be fan-folded upon one another.

Abstract: The improved bag and method of the present invention introduces relates to a bulk bag which would include four (4) side portions, each of the side portions joined at their edges for forming a bulk container space therewithin, a susbstantially flat bottom portion attached to the side portions, with the bottom portion including a centrally positioned discharge spout, which would allow bulk contained within the bag to be discharged through the discharge spout. The bag would further include an upper top portion attached to the four (4) walls of the bag, the upper top portion being substantially cone - shaped, which may include an inlet spout at the top of the cone, for allowing bulk material to be poured into the bag. When bulk material is poured into the bag portion, the bulk material would form a cone of material within the cone portion of the bag, thus assuring that the walled portion of the bag has been filled with bulk.

Abstract: A continuous roll or stack of thermoplastic bags having improved openability is disclosed. The bags feature an area of permanently tacky, pressure-sensitive adhesive, applied to an outer surface of each bag. When a bag is pulled from the roll or stack, the adhesive temporarily adheres one side of the bag to the roll or stack, causing the front and back of the bag to separate slightly, thereby enhancing openability. Also disclosed are thermoplastic bags onto the surface of which an area of adhesive is applied in such a manner that the bags are self-closing when twisted shut in the area of the adhesive.

Abstract: A sign storage and carrying apparatus having first and second cover panels and having first and second side walls fixed to the opposed lateral edges of the cover panels to retain the cover panels in a parallel, substantially coextensive condition. An upper wall is connected to the top edges of the cover panels to form a protective pocket having a base opening. Fastening members are fixed to the opposed interior surfaces of said first and second cover panels for recurringly sealing selected portions of the base opening. Preferably, one fastening member is a hook fastening strip and the opposite fastening member is a loop fastening strip. A handle is mounted to the upper wall to facilitate carrying of the apparatus, while stacking strips are fixed to the exterior surfaces of the cover panels to permit stacking.