Abstract: The container includes a main sidewall, a first end-wall connected to a first end of the main sidewall, and a first structure, a first side of the first structure being connected to a second end of the main sidewall, the main sidewall, the first end-wall and the first structure at least partially defining a primary storage area, the first structure including a secondary sidewall extending from a second side of the first structure, and a including a protrusion extending from a first side of the cover, the protrusion being inserted within the secondary sidewall to be releasably mated with the secondary sidewall, a first central portion of the cover and a second central portion of the first structure at least partially defining a secondary storage area, a first peripheral portion of the cover and a second peripheral portion of the first structure at least partially defining a peripheral cavity.

Abstract: Disclosed is a plate cover system having a plurality of plate covers that can be configured to stack upon each other in a protracted configuration and/or or a collapsed configuration. In one embodiment, a first plate cover can be used to support a second plate cover by placing the second plate cover on top of the first plate cover, wherein a volume of space exists between the first plate cover and the second plate cover. The system can be transitioned between the protracted configuration and the collapsed configuration by slidably engaging channels disposed on sidewalls of the plate covers. Some embodiments include a rotation retention mechanism for securing the plate covers in place when in a protected or a collapsed configuration.

Abstract: The invention relates to a closure cap for a substantially cylindrical vessel, with a lateral surface, a closed end and an open end, and with a tear-open strip having a grip tab for opening the closure cap. In order to produce closure caps which are designed such that they can be applied by machine to substantially cylindrical vessels, it is proposed within the context of the invention that the lateral surface is substantially cylindrical, at least in the area of the open end, and that the closure cap is of stackable design and has means for stacking at least two closure caps with defined spacing. The invention is based on the finding that, for cost reasons, it is useful if also closure caps for substantially cylindrical vessels can be stacked, i.e. pushed onto one another, during transport as they then take up less space.

Abstract: A lid for a container includes snap-fit hooks for interlocking engagement in complementing latching openings of an outwardly projecting flange of a jacket of the container, and stacking parts disposed on a lower side of the lid close to the periphery for form-fitting engagement in complementing stacking parts on an upper side of a further said lid, when the lids are stacked. The lower side of the lid and the upper side of the further lid have each a central region that forms a contact area via which compressive forces are transmissible in the presence of a contact between the contact areas of the lower side of the lid and the contact area of the upper side of the further lid.

Abstract: An inverted double dome double vacuum debulk tool having separable upper and lower chamber portions which can be assembled to form a vacuum chamber. In accordance with some embodiments, the top and bottom halves each comprise a circular cylindrical sidewall closed at one end by an inverted dome. The domes may be hemispherical or semi-elliptical with convex sides facing the chamber interior space. A base plate on which the composite patch rests is removable from the vacuum chamber. Various fittings pass electrical power and vacuum into the tool and sensor outputs out of the tool.

Abstract: A dispenser includes a container having an opening; and a cover coupled to the container and configured to cover the opening, the cover including a base coupled to the container, the base having side walls defining an interior opening; a first tab and a second extending outwardly in a first direction from a first one of the side walls, wherein the second tab is spaced from and substantially parallel to the first tab, a third tab and a fourth tab extending outwardly in a second direction substantially opposite to the first direction from a second one of the side walls, wherein the fourth tab is spaced from and substantially parallel to the third tab; and a lid tray rotatably coupled to the base and configured to cover the interior opening.

Abstract: A lid for a beverage cup includes an annular mounting portion to removably, sealingly, engage the open lip of a round beverage cup; a raised annular ridge inset from the mounting portion extending from a first end to a second end; a central portion spanning the annulus and including an aroma aperture at the center; a dispensing portion spanning between the annular ridge first end and second end including a front flat portion, a sloped dispensing aperture surface, and a dispensing aperture disposed on the sloped surface, the dispensing aperture comprising a triangle with rounded corners having a base proximate and parallel to the intersection edge and an apex proximate the upper edge; and, the raised annular ridge and dispensing portion defining a continuous containment surrounding the central portion.

Abstract: An exemplary embodiment of a vessel-lid combination includes a ceramic or glass vessel having an open top surrounded by a peripheral edge, a lid fabricated of a plastic material, and a seal structure. The lid is configured to attach to the open top by means of a latch or set of latches integrated with the lid, and the seal structure is configured to provide an air-tight seal between the lid and the peripheral edge of the vessel when the lid is attached to the vessel.

Abstract: A thermoformed container system with a tray and a lid mounted on the tray, that includes special structures to help two or more containers to stand on their bottom edges when nested together, even though each individual container would be too unstable to stand in isolation. Alternative embodiments of the invention include a product case pack comprising at least two containers with product inside each container, and a method of retail sales display of two or more containers, where the containers are adapted to stand on their bottom edges when nested together.

Abstract: The present invention comprises a stackable ballasted roof mounting solar panel mount unit integrally formed into a single piece. The mount unit comprises a plurality of generally elevated side walls of a ballast receiving basket. Each side walls defines a downwardly facing open channel that is configured to receive a corresponding side wall from a corresponding solar panel mount in a stacking relation. The mount unit further comprises a first pair of posts, wherein each of the first pair of posts forms a downwardly facing post receiving first mouth that is configured to receive a corresponding post from a corresponding first pair of posts of a corresponding solar panel mount in a stacking relation.

Abstract: The invention relates to a container (1) for intermodal transport by air and ship, train and/or motor car, comprising a block-shaped housing (2), which is characterized in that there are provided at the corners of the housing (2) castings (6) which are used for positioning when stacking the container (1) and/or for securing the container (1) during transport, and a plurality of containers (1) can be combined to form transport units (25) the base area of which corresponds to that of a standardized sea cargo container.

Abstract: A lid for securing to the brim of a container, the lid including a container closure having a disk shaped member with a periphery for mating with the brim of the container. The periphery includes annular inner and outer side walls with at least one annular rib disposed on each of the inner and outer side walls. The ribs of the annular walls form a gripping area to secure the lid to the container for preventing leaks and accidental spillage. A top wall interconnects the inner and outer side walls and includes visual cues for viewing the brim of the container when the lid is affixed to the brim. The lid additionally includes a pronounced wedge shaped sipping spout projecting upwards from the container closure. The container closure includes a circular indented channel for stacking one lid covered cup over another with additional stability provided by the sipping spout.

Abstract: A storage container system has a plurality of container bases and a plurality of lids for the bases. Each of the bases has a bottom, a continuous side wall extending up from the bottom and terminating at a top edge, an interior storage space within the side wall above the bottom, and an open top bounded by the top edge. Each of the lids has a main panel section, a perimeter skirt assembly around the main panel section, a top side, and a bottom side. Each of the plurality of lids is configured to close off the open top of any one of the plurality of container bases by connecting the perimeter skirt assembly to the side wall near the open top. A first snap structure is provided on each of the plurality of lids. Each first snap structure has one component configured to connect to a mating lid component of the first snap structure on any other one of the plurality of lids to connect any two of the plurality of lids together.

Abstract: Stackable lids for a container each include a top surface facing generally in a first direction and a bottom surface opposite the top surface and facing generally in a second direction. Pivotable wing portions extend from each side edge of the lid and each pivotable wing portion is joined to its respective side edge by a hinge. The wing portions are moveable between engaged and disengaged positions, and an inner surface of each wing includes a tab member configured for detent engagement with a rim of the container. The lid also includes corner portions extending between the side edges. Each corner portion includes a skirt portion extending generally in the second direction. Each corner portion also defines a recessed shoulder configured to receive the skirt portion of another when the lids are stacked.

Abstract: A metallic lid for a can of the type which presents an opening defining a seating, said lid comprising, in a single piece, a bottom wall which incorporates, superiorly and peripherally, a side wall provided with a free upper edge and designed to be frictionally seated and axially retained in the interior of the seat. According to the invention, the bottom wall comprises a peripheral annular portion adjacent to the side wall, a median portion and an annular rib portion having the cross section in the approximate form of an inverted ‘U’, with the free edges of is lateral legs being respectively incorporated to the adjacent edges of the peripheral annular portion and median portion of the bottom wall.

Abstract: A container adapted to be stacked on top of a second container is provided. The container includes a first end wall and a sidewall having a first end and a second end. The container includes a first seam coupling the first end wall to the first end of the sidewall, the first seam including a shoulder extending inwardly from an outer surface of the first seam. The container includes an alignment feature extending from the shoulder away from the first end wall. The alignment feature is adapted to align the container relative to the second container and to resist lateral movement of the container relative to the second container when the container is stacked on top of the second container.

Abstract: A package comprises a lid and a container forming a lower contact area, the container having a receiving space bordered by a side wall, an apron extending along an upper region of the side wall, and a tamper-evident closure preferably including a tamper-evident tab which, after filling the packaging container, can be detached by a consumer. The lid is formed as a clamp-on or clip-on lid and can be fixed to the upper container rim, wherein the tamper-evident tab is transparent and the container has an optical indicator for marking the tamper-evident tab.

Abstract: An all plastic paint container assembly comprising a container, a ring assembly attached to the rim of the container and a pry-off plastic closure having a dual sealing arrangement with the ring member and an undercut lock at a location which provides maximum circumferential area. Containers of this design can be stacked both with and without the ring members attached. Three embodiments are disclosed, providing double and triple closure locks and multiple seals.

Abstract: A lid for industrial or commercial large size solid waste containers has a ribbed single layer central portion and a peripheral edge having a hollow double wall boxed configuration. The lids have substantial symmetry so that the lids may be stacked and nested with alternate lids oriented in opposite front-to-back directions.

Abstract: A thermoformed container system with a tray and a lid mounted on the tray, that includes special structures to help two or more containers to stand on their bottom edges when nested together, even though each individual container would be too unstable to stand in isolation. Alternative embodiments of the invention include a product case pack comprising at least two containers with product inside each container, and a method of retail sales display of two or more containers, where the containers are adapted to stand on their bottom edges when nested together.

Abstract: The structurally reinforced container includes a base having a bottom, side walls, corners and a top peripheral edge defining an open top end. A number of ridges are formed in at least one of the side walls and corners. The ridges are in the configuration of at least one arch that has an apex where the apex of the at least one arch is proximal to the open top end of the base. A lid resides in communication with the top peripheral edge of the base to releasably close the top end of the base. The integrated arches provide reinforcement to the base of the container to increase top load resistance without increasing the thickness of the material used.

Abstract: Disclosed herein is a lid for a tray having at least one reservoir for accommodating a condiment.

Abstract: A lid for securing to the brim of a container, the lid including a container closure having a disk shaped member with a periphery for mating with the brim of the container. The periphery includes annular inner and outer side walls with at least one annular rib disposed on each of the inner and outer side walls. The ribs of the annular walls form a gripping area to secure the lid to the container for preventing leaks and accidental spillage. A top wall interconnects the inner and outer side walls and includes visual cues for viewing the brim of the container when the lid is affixed to the brim. The lid additionally includes a pronounced wedge shaped sipping spout projecting upwards from the container closure. The container closure includes a circular indented channel for stacking one lid covered cup over another with additional stability provided by the sipping spout.

Abstract: A handle attached to cookware piece configured to position the cookware piece within a larger cookware piece in a nested arrangement. The handle may include a body having a slot disposed within a bottom surface of the handle body. The slot may be configured such that when a smaller cookware piece is positioned within a larger cookware piece, an upper edge the smaller cookware piece is equal to or less than the same height of an upper edge of the larger cookware piece. The smaller cookware piece may be held by the slot within the larger cookware piece in a substantially horizontal orientation.

Abstract: A protective seal for application onto a beverage can, which is capable by virtue of its geometric configuration of providing efficient sealing against possible contamination that may come into contact with the upper outer portion of the can, and providing high resistance to penetration of substances and/or contaminants onto the can surface by virtue of the cooperation of compressive forces exerted by the surfaces of the protective seal onto the can.

Abstract: A produce container comprises a basket portion and a closure portion, which are hingedly secured to one another to be relatively movable between an open configuration and a closed configuration. The container can be secured in the closed configuration by way of at least one tab projecting upwardly from a front edge of a basket portion peripheral lip, which is received within a corresponding slot defined inwardly of the front edge of a closure portion peripheral lip. Each slot extends into a collocated recess in the outer surface of the closure portion peripheral lip, and each tab has an outwardly extending locking projection which, in the closed configuration, engages a corresponding recess engagement surface. Each locking projection terminates inwardly of the outer surface of the front edge of the closure portion peripheral lip and each tab terminates below the upper surface of the closure portion peripheral lip.

Abstract: A storage container system has a plurality of container bases and lids. Each base has a bottom, a continuous side wall extending up from the bottom and terminating at a top edge, an interior storage space within the side wall above the bottom, and an open top bounded by the top edge. Each lid has a main panel section, a perimeter skirt around the main panel section, a top side, and a bottom side. Each lid is configured to close off the open top of any one of the plurality of container bases by connecting a part of the perimeter skirt to the side wall near the top edge. Each lid has a first connecting structure with a lid-to-lid component and a mating lid-to-lid component. Each lid-to-lid component is configured to connect to the mating lid-to-lid component on any other one of the plurality of lids to connect any two of the plurality of lids together. Each lid also has a lid-to-base component, which is part of a second connecting structure and is different from the first connecting structure components.

Abstract: An anti-spill food or small item container assembly having an open top and defining a chamber adapted to contain food. A lid is detachably secured to the container and the lid includes a flexible portion extending across and covering the open top of the container. The flexible portion includes at least one slit which forms at least one flap in the lid to permit access to the interior chamber of the container in which the food is contained. Furthermore, the flexible portion is constructed of a material having shape memory so that, after deflection of the flap, the flap will substantially return to its original position.

Abstract: A canister includes a closure coupled to a container to close a mouth opening into an interior region formed in the container. The closure includes a lid having a plate and a rim extending around the plate.

Abstract: This invention is directed to a food container comprising a lid and a base. The lid and base form three seals, including a locking seal, to prevent the leakage or spoilage of food during transport or temporary storage. Blades on the lid sealing edge and blades on the base sealing edge strengthen said edges, and further reinforce the seals formed between the lid and base. The lid and base, separately or when assembled, are stably stackable requiring a minimal amount of storage space.

Abstract: A container cover for use with a container having a neck. The cover includes a lid, a skirt extending downward from the circumference of the lid, and a concentric plug seal extending from the lid inside the skirt. The cover also includes an annular recessed channel circumscribing the center of the lid, with the channel including at least one hole in a side wall of the channel, the hole allowing air to pass through the lid. The skirt preferably includes six lock panels. The sides of the lock panels are defined by vertical slots in the skirt, and each lock panel features at least one inwardly-projecting lock. When the cover is locked on the container, the locks engage a lip on the container neck. When a user wishes to remove the cover, the user pulls up on the edge of a lock panel, disengaging the locks from the container lip and removing the cover.

Abstract: A universal lid for industrial or commercial large size solid waste containers, has a ribbed single layer central portion and a peripheral edge having a hollow double wall boxed configuration. The boxed perimeter may have a predetermined height such as approximately one inch, and the lid is provided with hinge lugs having a vertical extent substantially more but not more than twice than said predetermined height. In addition, the lids have substantial symmetry so that the lids may be stacked and nested with alternate lids oriented in opposite front-to-back directions. With this type of lid, the advantages of both single layer and double layer lid constructions may be realized.

Abstract: A container 100 includes a cover 102 and a base 104. The container cover 102 includes a first closure portion, an engagement portion 208, and an alignment portion. The base 104 includes a second closure portion. The first closure portion of the cover 104 is sealingly engageable with the second closure portion of the base 104 to define a sealed storage area. The covers 102 stack together in two different ways. First, the covers 102 can be stacked into an “aligned” stack. Second, the covers 102 can be stacked into a releasably locked stack. The alignment portion of the cover 102 is engageable with the alignment portion of a second cover 602 to form an aligned cover stack. The engagement portion 208 of the cover 102 includes one or more engagement lugs 424 that are engageable with corresponding engagement lugs 624 of the engagement portion 608 of a second cover 602 to form a releasably locked cover stack 750.

Abstract: The invention is directed to a thermoformed, rectangular disposable storage container. The container includes a base and lid. The base includes arched front and rear walls to redistribute the pressure placed on the top of the container and to generally evenly balance the load force around the container front, rear and end walls to prevent buckling of the container front or rear walls. The container lid includes an arched front wall and rear wall which generally corresponds to the degree of arch of the front and rear walls of the base.

Abstract: A container cover for use with a container having a neck. The cover includes a lid, a skirt extending downward from the circumference of the lid, and a concentric plug seal extending from the lid inside the skirt. The cover also may include vent holes in the lid. The skirt preferably includes six lock panels. The sides of the lock panels are defined by vertical slots in the skirt, and each lock panel features at least one inwardly-projecting lock. When the cover is locked on the container, the locks engage a lip on the container neck. When a user wishes to remove the cover, the user pulls up on the edge of a lock panel, disengaging the locks from the container lip and removing the cover.

Abstract: A lid for industrial or commercial large size solid waste containers has a ribbed single layer central portion and a peripheral edge having a hollow double wall boxed configuration. The lids have substantial symmetry so that the lids may be stacked and nested with alternate lids oriented in opposite front-to-back directions.

Abstract: Apparatus includes a motor-vehicle, internal-combustion-engine air intake manifold having an intake-manifold first shell attachable or monolithically joined to an intake-manifold second shell to surround an internal manifold volume. The first shell has a wall with at least a portion having undulating concave and convex regions as defined exterior to the internal manifold volume of the attached or monolithically-joined first shell and second shell.

Abstract: A water resistant absorbent towel dispenser. The dispenser includes a container having top, bottom and side walls housing a supply of absorbent towels, and an exterior handle for facilitating transport of the dispenser. The top wall includes a finger-accessible opening through which absorbent towels may be withdrawn. In certain embodiments, the top wall is convex upwardly, but is flexible to enable it to be depressed when dispensers are stacked vertically so as to come into load bearing contact with the towel supply. In some embodiments, the top and bottom walls have interlocking configurations to add lateral stability to vertically stacked dispensers.

Abstract: A tub in a generally rectilinear configuration has a rear face, a front face and side faces. The tub has a closed bottom and an open top. The tub contains heating elements with controls in the front face. The controls are adapted to be manipulated by a user during operation and use. A lid in a generally rectilinear configuration has a posterior element and an anterior element. The posterior element has a rear face, an open front and side faces. The posterior element has an open bottom and a closed top. The anterior element has a front face, an open rear and side faces. The posterior element has an open bottom and a closed top. The rear of the anterior element is adapted to slidably couple with respect to the front of the posterior element. In this manner movement is provided between an expanded and contracted orientation.

Abstract: A universal lid for industrial or commercial large size solid waste containers, has a ribbed single layer central portion and a peripheral edge having a hollow double wall boxed configuration. The boxed perimeter may have a predetermined height such as approximately one inch, and the lid is provided with hinge lugs having a vertical extent substantially more but not more than twice than said predetermined height. In addition, the lids have substantial symmetry so that the lids may be stacked and nested with alternate lids oriented in opposite front-to-back directions. With this type of lid, the advantages of both single layer and double layer lid constructions may be realized.

Abstract: The present disclosure pertains to an assembly, including a container that includes a profiled closure such as a screw thread or a bayonet fitting, whereby the closure part of the container is arranged on the inside thereof, and a lid, having a closure counterpart matching that of the container for providing a seal, whereby the closure part of the lid is arranged on the outside thereof. The disclosure further relates to a container and a lid assembly or combination. The container is provided with a sealing surface, and the lid is provided with a matching sealing surface, such that in the closed state of the assembly at least the closure part and the sealing surface of the lid are located inside the container and below the rim thereof.

Abstract: The container can be locked into a stack of containers. A container cover locks onto the top of a container base to define a sealed area for storage. Additionally, the bottom of a second container base can be locked onto the top of the cover of a first container. In this fashion, when closed containers are stacked, they form a locked stack that is more structurally rigid and therefore less precarious than a traditional, non-locked container stack. When not in use, the bases can be formed into a nested stack, and their covers can be locked together to form a locked cover stack. The locked cover stack can be locked to either the top or bottom of the nested base stack to form a rigid stack. In some embodiments, a cover can be turned upside down and its bottom face locked onto the bottom face of a base.

Abstract: A produce container comprises a basket portion and a closure portion, which are hingedly secured to one another to be relatively movable between an open configuration and a closed configuration. The container can be secured in the closed configuration by way of at least one tab projecting upwardly from a front edge of a basket portion peripheral lip, which is received within a corresponding slot defined inwardly of the front edge of a closure portion peripheral lip. Each slot extends into a collocated recess in the outer surface of the closure portion peripheral lip, and each tab has an outwardly extending locking projection which, in the closed configuration, engages a corresponding recess engagement surface. Each locking projection terminates inwardly of the outer surface of the front edge of the closure portion peripheral lip and each tab terminates below the upper surface of the closure portion peripheral lip.

Abstract: A food container including a container cover, a container body, and an interlocking arrangement which includes a stacking seat continuously indent at a top surface of the container cover along a peripheral edge thereof and an engaging rim continuously protruded at a bottom surface of the container body along a peripheral edge of the bottom wall, wherein the engaging rim has a size and shape geometrically matching with the stacking seat in such a manner that when the container is arranged in stack formation above another the identical container, the engaging rim is complementarily coupled with the stacking seat to engage the bottom surface of the container cover with the top surface of the identical container so as to substantially retain said two containers in position and avoid a lateral relative movement between the two containers.

Abstract: A beverage holder device made from a flexible foldable cylindrically-shaped insulated sleeve with a longitudinal seam that includes a piping or welt material along said seam. The sleeve has an inside diameter sized to receive and hold a beverage container. An elongated bracket is mountable to a vertical surface. The sleeve has a foldable insulated bottom portion which is attached to the sleeve to prevent the beverage container from dropping through the sleeve. The bracket has a longitudinal channel and a corresponding opening therein with a closed bottom end and an opening at its upper end. The channel is sized to receive by sliding engagement therein the piping or welt material so that when the piping or welt material is slid into the channel starting from the channel's upper end, the piping or welt material and the sleeve are held in place by the bracket.

Abstract: A water resistant absorbent towel dispenser. The dispenser includes a container having top, bottom and side walls housing a supply of absorbent towels, and an exterior handle for facilitating transport of the dispenser. The top wall includes a finger-accessible opening through which absorbent towels may be withdrawn. In certain embodiments, the top wall is convex upwardly, but is flexible to enable it to be depressed when dispensers are stacked vertically so as to come into load bearing contact with the towel supply. In some embodiments, the top and bottom walls have interlocking configurations to add lateral stability to vertically stacked dispensers.

Abstract: The present invention relates, generally, to food containers used in storing and displaying heated foods, as well as in serving foods from these containers. The food container of the present invention is an improvement over the conventional prepared food containers in that it features, among other things, an improved handle, where the heat from the container is not fully felt by the person holding the container, while still providing an advanced sealing mechanism to prevent the escape of the contents of the container.

Abstract: The covers stack together in two different ways. First, the covers can be stacked into an “aligned” stack. The aligned stack provides structural rigidity for bulk handling during manufacturing. Second, the covers can be stacked into a “locked” stack. The locked stack provides even more structural rigidity than does the aligned stack and is useful when storing unused covers. The cover includes a first closure portion, an engagement portion, and an alignment portion. The base includes a second closure portion. The first closure portion of the cover is sealingly engageable with the second closure portion of the base to define a sealed storage area. The alignment portion of the cover is engageable with the alignment portion of a second cover to form an aligned cover stack. The engagement portion of the cover is engageable with the engagement portion of a second cover to form a locked cover stack.

Abstract: The present invention is directed to a lid (5) with a central lid portion (6) and with a peripheral clamping groove (7) formed between an outer groove wall (8) and an inner groove wall (9) for being clamped onto a beaded rim (4) of a cup-shaped receptacle (1). A constriction (10) is provided on at least a peripheral section of the outer groove wall (8), the constriction (10) forming a projection (14) into the interior of the groove (7), this projection (14) comprising a projecting tip (15), an upper wall (16) and a lower wall (17), and the projecting tip (15) defining a horizontal plane (H). The invention is characterized in that an angle (?) between the horizontal plane (H) and a tangential plane (T16) to the end of the upper wall (16) adjacent the projecting tip (15) is smaller than an angle (?) between the horizontal plane (H) and a tangential plane (T17) to the end of the lower wall (17) adjacent the projecting tip (15).

Abstract: A container 100 includes a cover 102 and a base 104. The cover 102 of the container 100 includes a first closure portion 310, an engagement portion 308, and an alignment portion. The base 104 includes a second closure portion 212. The first closure portion 310 of the cover 102 is sealingly engageable with the second closure portion 212 of the base 104 to define a sealed storage area. Multiple covers 102 stack together in two different ways. First, the covers 102 may be stacked into an “aligned” stack. Second, the covers 102 may be stacked into a locked stack. The alignment portion of the cover 102 is engageable with the alignment portion of a second cover to form an aligned cover stack. The engagement portion 310 of the cover 102 is receivingly engageable by the engagement portion 308 of a second cover 602 to form a locked cover stack 728.