Abstract: A building including a metal joint is provided with a damping member that is mounted between at least a pair of structures and yields in accordance with relative displacement between the structures. The damping member includes strength-suppression device that suppresses an increase of strength after yield, and exerts a damping effect with rocking or expansion and contraction of at least one of the structures.

Abstract: An expansion joint and seal is provided that is adapted for adherence to a wall and floor interface. The joint is operative to seal the interface such that self-leveling materials cannot flow between the wall and the floor. When adhered to the interface, a compressive member may be disposed coincidental to the wall. This compressive member allows for expansion of solidified self-leveling materials relative to the wall. In one arrangement, the joint and seal utilizes a flexible sheet member having a bottom surface that is adapted for adherence to the interface of a wall and floor. A compressible member is attached to the top surface of the flexible sheet member. The bottom surface of the flexible sheet member may also include a peel-away release member that covers an adhesive disposed on the bottom surface.

Abstract: Expansion joint system of a concrete slab arrangement, comprising an expan-sion joint reinforcement to be arranged between a first and a second concrete slab (1, 2), the expansion joint reinforcement comprising at least two local dowels (3)transferring loads perpendicular to the slab plane. The dowels com-prise a dowel plate (4) and a casing part (5). The dowel plate (4) and the cas-ing part (5) are attached to the concrete slabs on different sides of the joint. The casing part (5) prevents the dowel plate from adhering to the concrete slab and allows the dowel plate (4) to move inside the casing part and thus allows the movements of the slabs (1, 2) in the horizontal direction. The dowels (3) are installed alternately relative to the joint so that the casing parts (5) of the adjacent dowels (3) are always installed on different sides of the joint.

Abstract: A fire resistive joint cover system operable to span a gap between two surfaces. The system generally may include first and second base members, a covering member, and an intumescent sheet. Each base member is operable to couple with one of the surfaces and the covering member is operable to couple with the base members to at least partially span the gap. In some embodiments, the covering member may be configured as a floating covering member and/or as a flexible elastomer seal.

Abstract: A crack inducer controls propagation of cracks in set concrete containing reinforcing bars. The crack inducer has an elongated, rigid core that is relatively narrow in a direction that is parallel to outer surfaces of the concrete. The core has a core width in a first plane that intersects the outer surfaces of the volume, that is at least 20% of the concrete volume width so that a crack in the volume of concrete is induced to propagate from the core and along the first plane. A plurality of spaced cross-plates are connected to the core and a water-stop may be included around part of the core.

Abstract: Buildings and walls are commonly constructed with exterior walls composed of specially treated engineered wood panels, cement panels, fiber cement panels, glass-matt-faced gypsum panels, and gypsum/cellulose sheathing panels. The spaces or edges between these exterior panels are sealed using the disclosed dual-tape-core joint treatment system and method of the present invention. After curing, a color matching acrylic-epoxy scratch coat or elastomeric primer followed by a textured finish coat is sprayed, brushed or rolled on the exterior panels.

Abstract: An expansion joint system for bridging a gap that is located between spaced-apart structural members. The expansion joint system may be utilized, for example, in roadway, bridge and tunnel constructions where gaps are formed between spaced-apart, adjacent concrete sections. The expansion joint system includes flexible moment connections for connecting vehicle load bearing members to the support member. In certain embodiments, the expansion joint system includes flexible moment connections and friction springs. The expansion joint system may be utilized where it is desirable to absorb loads applied to the expansion joint systems, and to accommodate movements that occur in the vicinity of the expansion joint gap in response to temperature changes, seismic cycling and deflections caused by vehicular loads.

Abstract: A fastening member and a magazine configured to deliver each of a plurality of the fastening members into a groove in a decking member. The fastening member includes a generally planar first surface, a generally planar second surface generally parallel to the first surface and at least one side generally perpendicular to the first surface and the second surface and circumscribing at least a portion of the first surface and the second surface, wherein the fastening member is configured to be positioned at least partially in a groove in a first decking member and the fastening member is configured to provide a nominal spacing between the first decking member and the adjacent decking member; and an expansion feature configured to accommodate expansion of an adjacent decking member adjacent the first decking member.

Abstract: A joint structure includes a splice plate and a gusset plate, which can prevent out-of-plane buckling of the gusset plate without the necessity of welding a stiffening rib plate thereon. The joint structure includes a gusset plate and at least one splice plate connected to the gusset plate. Each of the splice plates is constructed from section steel having a non-rectangular cross-section. The joint structure can be used in a building during assembly of the building or for reinforcement of the building.

Abstract: A door threshold may include upper and lower members for sandwiching carpet and/or carpet padding therebetween. The threshold may, in certain example embodiments, grip the carpet in order to prevent it from being pulled out from between the upper and lower threshold members. Thus, in certain example instances, the need for tacks (or carpet tack strip(s)) proximate the threshold can be reduced and/or eliminated. In certain example embodiments of this invention, the threshold structure may include a locating bracket that is provided proximate the door frame for frame alignment and security purposes, and/or one or more pans located under the threshold for locating and/or securing purposes. Levelers, shims and/or the like may be used in certain example embodiments in order to compensate for non-level flooring proximate the door.

Abstract: A transition joint comprising: 1) a generally W-shaped central portion including first, second, third, and fourth legs; 2) a first vertical flange extending upwardly form the first leg of the W-shaped central portion; 3) a second vertical flange extending downwardly from the fourth leg of the W-shaped central portion; 4) a first transition zone or land between the first and second legs and a second transition zone between the third and fourth legs; 5) a longitudinal drip edge extending downward from the first transition zone; 6) a T-shaped stucco anchor extending downward from the fourth leg intermediate the second transition zone and the second vertical flange; and 7) a floor line alignment guide extending longitudinally along the first vertical flange. The floor line alignment guide provides accurate positioning of the transition joint with respect to a building in order to create proper clearance for runoff of rainwater and condensation and prevent infiltration of rainwater into the floor line.

Abstract: A flanged nailing plate and a drywall nailing plate that work in conjunction with each other to provide an expansion joint. The flanged nailing plate is attached to the wall studs top plate with the interiorly extending flange forming a sill to support one end of the drywall nail flange with the other end nailed to the bottom chord of the truss with the length of the drywall nail flange variable, typically between one to three feet, depending on the installation.

Abstract: A seal serves to connect and/or seal between facade panels (2) and similar building parts and is provided with at least two sealing webs (6.1 and 6.2) spaced from each other and forming a compartment (5), the lips being attached at their edges to common connecting lips (7) shaped for attachment to the respective facade panels. Each sealing web (6.1 and 6.2) is designed to deform elastically to change its transverse spacing and is hinged to the connecting lip at its edge.

Abstract: A system and method are provided for forming expansion joints within artificial ground cover. An elongated expansion joint support is coupled with a length of expansion joint material. A lower end portion of the expansion joint support is shaped to engage a ground surface. The two structures may be coupled with one another in different positions to vary the resulting expansion joint height. The lower end portion of the expansion joint support may be shaped to have a ground engagement wall and to receive ground engagement spikes. No component parts need be removed from the system after the application of artificial ground cover adjacent thereto, thus permitting simultaneous application of ground cover on both sides of the expansion joint.

Abstract: A new configuration damper, for interconnecting two elements of a structure that undergo relative movements and deformations, that increase the level of damping when the overall structure is subjected to a loading condition is disclosed. The new configuration damper aides in controlling displacements, velocities and accelerations under dynamic loading in structural systems.

Abstract: Replacement Expansion Joint for Cement is an expansion joint for use with concrete. The preferred embodiment of the invention utilizes an arrow shaped plastic expansion joint with two holes bored inside the expansion joint. To use the preferred embodiment of Replacement Expansion Joint For Cement, an individual would remove deteriorating wooden expansion joints located in grooves between concrete slabs. The length of the wooden expansion joints would be measured to permit the user to purchase and install the proper length of replacement expansion joint. The user would then insert the expansion joint of the present invention with the arrow side facing toward the ground into the groove from the wooden expansion joint. The newly installed expansion joint would be much more resistant to the weather elements than the wooden expansion joints.

Abstract: A system for sealing a joint gap between structural substrate panels such as walls, ceiling and floors making use of a sealing member including a mounting section fixedly secured to one of the surfaces and a covering member extending outwardly therefrom into contact with the other substrate member. These walls, ceilings and floors can be movable relative to one another and thus the present invention provides a mechanism for sealing the joint gap between the substrates while allowing them to move with respect to one another. This is achieved by fixedly securing the sealing member to one of the substrates and urging it into abutting engagement with respect to the other substrate.

Abstract: Disclosed herein are panelized wall systems and methods for their construction, wherein the wall systems have elastomeric joints that are resistant to cracking. The walls are constructed with an elastomeric joint tape. The joint tape is made from an elastomeric backing material with an adhesive applied to a face, and optionally, a release liner laminated to the adhesive. In use, building panels are fastened to a frame with the edges adjacent to each other. The joint tape is applied to the seam between the panels and the wall is then finished with an elastomeric finish.

Abstract: A membrane assembly (100) has at least a pair of bottom sheet membranes (102), (102) and at least one top sheet membrane (104), wherein the bottom sheet membranes (102), (102) are adapted to attach to and cover respective pavement sections (106), (106) of a roadway (108), wherein the bottom sheet membranes (102), (102) are moveable relative to the top sheet membrane (104) in response to movement of the respective pavement sections (106), (106), and wherein the top sheet membrane (104) is adapted to support road surfacing material (112), while the top sheet membrane (104) extends over a gap (110) between the respective pavement sections (106), (106).

Abstract: A modular center plate for a cover that bridges the expansion gap and is supported by frame members of an expansion joint cover is made up of a plurality of formed members, each formed member being rectangular in plan and of uniform cross-section along an axis and having side edges parallel to the axis. The formed members are arranged with their side edges adjacent each other and with their ends overlying the support surfaces of the frame members of the expansion joint cover. End frame members are attached to the end edges of the formed members.

Abstract: A non-metallic pad for placement between equipment and its support, for example between a pipe and a beam supporting the pipe. The pad comprises an elongated main body, preferably having male and female dovetails on either end to permit connecting multiple pads together. In profile, the main body has a convex top and a flat bottom. The main body is of a lattice internal structure, with the ribs of the lattice running substantially vertically. The ribs terminate at one end against a closed top surface, and at the other end terminate at a common level to form an open bottom. Injection molding is preferably used to form the pad. Preferred non-metallic materials for the pad are plastics, including glass fiber filled polyurethane, glass fiber filled nylon, and rubber filled polypropylene.

Abstract: A method and apparatus for forming a sealed joint comprises a joint member having at least one elongate component that comprises a top surface, a bottom surface, a first component side and a second component side, wherein at least a portion of the top surface has a contour which is curved. In forming a joint a first member is formed on a substrate. The joint member is positioned against the first member and the substrate. A second member is formed on the substrate immediately adjacent to the joint member. In some embodiments the joint member comprises two components, one of which is removed following formation of the second member.

Abstract: The invention concerns a permanently functional gap seal on structures, in particular building structures, which ensures a reliable seal against penetrating moisture, this being achieved in that the cover layer has a profile which can be adapted to an installation situation over a joint or on an inner or outer corner and has a central part and side wings disposed on both sides of the central part, and in that at least the side wings have contact surfaces for contacting a sealant.

Abstract: A floor system composed of a finished flooring preferably secured to a subfloor, a plurality of shock absorber members are fixed to the bottom surface of the floor surface at spaced intervals and in which each of the shock absorber members includes an elastomeric base member provided with a cavity which accommodates an insert member for adjusting the cushioning ability of the base member.

Abstract: A method of fabricating an electrostatic actuator with an intrinsic stress gradient is provided. An electrode is formed on a substrate and a support layer is formed over the electrode. A metal layer is deposited onto the support layer via a deposition process. Deposition process conditions are varied in order to induce a stress gradient into the metal layer. The intrinsic stress in the metal layer increases in the direction from the bottom to the top of the metal layer. The support layer under the electrode is removed to release the electrostatic actuator.

Abstract: A bridging device for joint gaps (1) between building parts (2, 3) including bridge parts, with an expansion joint construction (4) bridging a joint gap (1). The expansion joint construction (4) permits position changes of the building parts (2, 3) with respect to one another. A safety construction (12, 15) is provided which permits a position change of the building parts (2, 3) with respect to one another without a separation destroying the function of the bridging device. The safety construction (12, 15) comprises at least two mutually firmly connected elements which upon exceeding of a defined threshold load are separated and movable with respect to one another. One element is firmly arranged on one of the building parts (2, 3) and the other element is part of the expansion joint construction (4) or receives the latter. The two connected element are defined by a rail (24)and a slide (25).

Abstract: An apparatus and method are disclosed for finishing a drywall installation which includes providing drywall mud; providing a continuous twisted strand having a plurality of layers of nonwoven fibrous cellulosic material, wherein at least one individual layer of the plurality of layers of nonwoven fibrous cellulosic material contains an accelerant effective for accelerating setting time of the drywall joint compound; feeding the continuous strand into a cutter and cutting the continuous strand into particles motivated by air pressure so as to generate a stream of cellulosic fibers wherein at least some of the cellulosic fibers contain the accelerant; generating a stream of the drywall joint compound motivated by air pressure; and combining the stream of drywall joint compound with the stream of cellulosic fibers while applying the combined streams onto a predetermined portion of the drywall installation being finished.

Abstract: The invention disclosed relates to a precast composite header joint system and method for forming and installing the same in a concrete deck structure. According to the invention, the header is cast and cured before being positioned and secured in a recess formed in one of the concrete slabs. A viscous bonding agent is then poured into the void spaces between the header and the concrete slab recess. The bonding agent cures and forms a solid material which fills all of the space between the header and the concrete slab recess. Adjacent headers installed in opposing concrete slab recesses are coupled together by a joint to provide a continuous deck structure.

Abstract: An improved joint edge assembly, of the type used in the construction of concrete slabs, is disclosed. The assembly comprises a longitudinal joint rail, preferably of steel, which is supported off the ground by temporary formwork. The joint rail is secured to the formwork by mounting brackets. The joint rail comprises first and second joint edge members that are connected to each other by connectors with self-release elements. A plurality of studs extends downward and outward from each of the joint edge members into the concrete slabs provide a positive mechanical connection between the slab and the joint rail. As the concrete shrinks during hardening, the self-release elements of the connectors allow the joint to freely open. The joint edge assembly thus provides a self-releasing expandable joint between adjacent slab sections, and protects the edges of the adjacent slab sections from damage. A dowel aligner may also be integrated into the assembly, to allow proper positioning of dowels within the slab.

Abstract: A construction assembly for interior works including prefabricated elements, wherein the prefabricated elements include a coating layer formed of at least one skim coat deposited on the prefabricated elements by a coating device; and at least one jointing material, e.g. a sealing coat, joint coat and/or joint pointing coat, which joints adjacent said prefabricated elements to form a substantially plane outer surface.

Abstract: The invention discloses an improved seal for providing protection against water, water vapor, and other vapors from entering into and permeating through a concrete slab. The seal includes three primary functional edges extending from a common junction, a first edge positioned substantially horizontally to be moisture proof fastened to a geo-membrane liner over which a slab is to be poured, a second edge extending downwardly to the first edge to be embedded into a foundation, and a third edge extending upwardly from the first edge to be embedded into the slab. The invention applies to both monolithic and non-monolithic pours.

Abstract: Disclosed herein are panelized wall systems and methods for their construction, wherein the wall systems have elastomeric joints that are resistant to cracking. The walls are constructed with an elastomeric joint tape. The joint tape is made from an elastomeric backing material with an adhesive applied to a face, and optionally, a release liner laminated to the adhesive. In use, building panels are fastened to a frame with the edges adjacent to each other. The joint tape is applied to the seam between the panels and the wall is then finished with an elastomeric finish.

Abstract: A joint structure includes a splice plate and a gusset plate, which can prevent out-of-plane buckling of the gusset plate without the necessity of welding a stiffening rib plate thereon. The joint structure includes a gusset plate and at least one splice plate connected to the gusset plate. Each of the splice plates is constructed from section steel having a non-rectangular cross-section. The joint structure can be used in a building during assembly of the building or for reinforcement of the building.

Abstract: An extruded connecting profile for two panels having peripheral edges includes a first frame element having a front side and an opposite rear side, the front side being shaped for engaging a peripheral edge of a first panel of the two panels. A second frame element is also provided having a front side and an opposite rear side the front side being shaped for engaging a peripheral edge of a second panel of the two panels. An elastic structure extending between the first and second frame elements is co-extruded with the first and second frame elements and is comprised of a material having a higher elasticity than the material of the first and second frame elements.

Abstract: The invention disclosed relates to a precast composite header joint system and method for forming and installing the same in a concrete deck structure. According to the invention, the header is cast and cured before being positioned and secured in a recess formed in one of the concrete slabs. A viscous bonding agent is then poured into the void spaces between the header and the concrete slab recess. The bonding agent cures and forms a solid material which fills all of the space between the header and the concrete slab recess. Adjacent headers installed in opposing concrete slab recesses are coupled together by a joint to provide a continuous deck structure.

Abstract: A cover assembly includes an elongated resilient cover for bridging a gap between horizontal structural members. The upper face surface of the resilient cover has spaced apart ribs extending transverse to the flow of traffic and an opposite surface formed with load bearing edge portions engaged for support with opposite lateral margins to the expansion joint. Between the load bearing edge portions the cover supports at least one rigid metal plate. In one embodiment, a central plate bridges the gap between two structural members and the at least two additional plates serve to urge the opposite lateral edges of the cover into supporting engagement with structural members. The cover has a thickness and sufficient elasticity to elastically deform for establishing supporting contact between the marginal support areas and underlying horizontal structural members.

Abstract: A sealing element for the recessed seat of an expansion joint in a concrete structure having an elastomeric profile (20) formed by two longitudinal lateral flanges (21) to be fixed to the end edges of the concrete structure (11), and a central portion (22) formed by walls depending from said flanges and converging to a central area to be fitted inside the seat (12), and shaped to support the hydrostatic pressure upstream of the concrete structure (10). A flexible duct (30) is installed inside the seat (12) below the central portion central area and provided with radial bores (31) opened to the inside of the seat to allow the selective feeding of precatalyzed polymeric resin to the inside of the seat (12), after the elastomeric profile (20) has been mounted and affixed to the concrete structure (10). The tube can be separate from the profile, attached to the central area, or the central area can have a W shape and the tube be within the lower portion of the W.

Abstract: A fire barrier transition (10,110,210,310) comprises a first section (130,230,330) to mate with a first fire barrier (14) in a first expansion joint (16), a second section (132,232,332) to mate with a second fire barrier (18) in a second expansion joint (20), and a center section (134,234,334) therebetween to seal a gap (12) between the barriers (14,18). The first section (130,230,330) and the second section (132,232,332) each present either a convex or a concave cross-section with two sidewalls (136,236,336) and a bight section (138,238,338) therebetween. Thus, the transition (10,110,210,310) preferably presents a specific shape with the first section (130,230,330) and the second section (132,232,332) each presenting channels aligned at an angle between the joints (16,20). The barriers (14,18) can slide between the sidewalls (136,236,336) and engage the bight sections (138,238,338), thereby mating with and sealing to the first section (130,230,330) and the second section (132,232,332).

Abstract: The invention relates to a joint cover comprising a base section to be fixed onto a support; a covering section; and one or more intermediate parts designed to receive the covering section by clipping, the intermediate part or parts defining a cavity for receiving a head of a longitudinal tab that the covering section comprises, and comprising on each side of a plane passing through an opening for access to the cavity, at least one external rib able to co-operate, by clipping of opposite shapes, with means of a longitudinal gully of the base section, and at least one internal tab for retaining said head in the intermediate part.

Abstract: Disclosed is a unitary resilient insert member for filing an expansion joint gap formed between adjacent concrete slabs, floor tiles, or the like wherein the insert member consisting essentially of a preassembled wedge shape form. Also disclosed is a method for sealing the gap located between adjacent flooring or structural members by filling the said gap with a sealing material insert.

Abstract: A seismic roof motion-absorbing gap cover assembly includes an elongated y-axis slideway affixed to a building unit B on one side of the gap and extending parallel to the gap and a y-axis slider slidably received on the y-axis slideway. Roof support members are secured to the y-axis slider in spaced apart relation against horizontal movements. A roof having one end affixed to a building unit A on the other side of the gap spans the gap and is supported on the roof support members by elongated spaced-apart x-axis slide members for movement along an x-axis perpendicular to the gap. Each x-axis slide member has a length such that it is supported by the roof support member throughout a range of displacements in the x-axis direction of the building units between maximum and minimum design displacements in an earthquake from a neutral position.

Abstract: The present invention provides a device for transitioning between a first floor covering and a second floor covering wherein the transition device includes an elongated core and a covering. The elongated core has a top, a bottom, opposing sides and opposing ends. The covering is attached to the elongated core and covers the top and opposing sides of the elongated core. The present invention also provides method for manufacturing the transition device. In addition, the present invention provides a system having an elongated core and a covering as described above. A first floor covering is attached to the floor and abuts one side of the transition device. Similarly, a second floor covering is attached to the floor and abuts the other side of the transition device.

Abstract: A method and apparatus for positioning mild steel reinforcing bars within a precast, moment resisting frame of a building. The apparatus includes a hand-receiving access component that can be installed within the concrete beams that make up the building frame so as to permit convenient access to the reinforcing bars that are slidably carried within bar receiving passageways formed within the concrete beams. Additionally, the apparatus includes a bladder-receiving component that can be installed within the concrete beams that make up the building frame in a manner to permit an expandable bladder to be conveniently positioned within the cable receiving passageways formed in the beam. When in position within a cable-receiving passageway, the expandable bladder spans the interface between the beam and the column and effectively prevents grout from entering the cable passageway during the grouting step.

Abstract: Disclosed is a unitary resilient insert member for filing an expansion joint gap formed between adjacent concrete slabs, floor tiles, or the like wherein the insert member consisting essentially of a preassembled wedge shape form. Also disclosed is a method for sealing the gap located between adjacent flooring or structural members by filling the said gap with a sealing material insert.

Abstract: A bridge expansion joint assembly includes at least a first expansion module and a second expansion module on opposing bridge structures. The first expansion module includes a first hinge pivotally mounted to a first bridge structure so the first hinge can rotate about a first axis, and a first group of fingers pivotally mounted to the first hinge so the first group of fingers can rotate about a second axis. The second expansion module includes a second hinge pivotally mounted to a second bridge structure so the second hinge can rotate about a third axis, and a second group of fingers mounted, either fixedly or pivotally, to the second hinge. The first group of fingers and the second group of fingers are interdigitated and rest upon a sliding support.

Abstract: A seismic/expansion joint seal and cover comprising a cover plate, and a central spine extending downwardly from said cover plate. At least one layer of a resilient compressible foam sealant is provided on each side of the spine.

Abstract: A sealing arrangement which comprises at least two abutting components that form a gap therebetween and a seal that sealingly bridges the gap. The inventive sealing arrangement is characterized in that the seal entirely consists of a matrix or is provided with a matrix representing a composite system. The matrix is combined with a base body and is a pasty mixture comprising a water-soluble material. A lubricant and a swelling agent which can be activated by means of water as well as optionally additional additives are mixed into the material. In an advantageous embodiment, the matrix is introduced into the chamber. The wall of the chamber is configured in the form of a web that can be torn out. The web is removed before assembly. The base body consisting of an elastomeric material is provided with channels and grooves which extend in an extruded-like manner.

Abstract: The invention provides a resiliently deformable construction element covering (10) which permits a structure constructed using said covering to deform in sympathy with weather and other natural forces and to recover to substantially to its original state. The covering (10) includes a resiliently deformable film (12) having at least a portion (46) extending beyond the surface of the construction element (40) onto which the film is to be applied thereby to a define a flap (46) which overlaps onto an adjacent construction element, and an adhesive (16) for applying the film (12) to the construction element. The covering (10) also includes a coating composition or system (22) capable of being applied to the film and of dissipating, most of any decorative damage over an area around a stressed area of the film which is causing the decorative damage thereby to form individual cracks in the coating composition that are substantially invisible to the naked eye.

Abstract: A method for restoring load transfer capability across a joint between two adjacent concrete slabs includes cutting a perpendicular to the joint and extending into each of the adjoining slabs. A generally flat joint tie is positioned in the slot before filling the slot with polymer concrete. The joint tie may have holes extending between the broad faces of the joint tie, with rounded corners, and made of fiberglass.

Abstract: An expansion joint for a parking structure includes first and second rails for mounting on adjacent slabs at opposite sides of a gap therebetween and a cover plate that overlies the rails and covers the gap while permitting relative movement between the slabs. A series of turnbars are pivotally coupled to the underside of the cover plate using ball and socket joints so that lateral loads imposed on the cover plate are transmitted directly into the turnbars, minimizing the risk of shear failure between the cover plate and the turnbars. At the same time, the ball and socket joints allow the cover plate and turnbars to tip with respect to one another. The turnbars have spherical end portions that are received in complimentary channels in the respective rails so that the turnbars maintain the cover plate centered over the gap.