Load actuated baffle

A device for reinforcing, baffling or sealing a vehicle structure that includes hinge structures for allowing the member to be moveable within a cavity and free of any spring effect during movement.

TECHNICAL FIELD

The present invention relates generally to a baffling, sealing, or reinforcement member that includes hinge structure for allowing the member to be moveable within a cavity and free of any spring effect during movement.

BACKGROUND

The transportation industry continues to require methods of baffling, reinforcement and sealing that provide improved functionality while simultaneously providing reduced weight and cost. Often, the assemblies utilized will be required to move during the installation and manufacturing process. As a result, efforts have been made to produce parts that are movable, any such parts are formed to move but fail to return to the desired location within a cavity. There is thus a need in the art of sealing for parts that are both movable and yet formed to re-locate to a specific location after movement.

SUMMARY OF THE INVENTION

The present teachings meet the aforementioned inert by providing in a first aspect, a method for baffling, reinforcing or sealing of a cavity of a vehicle comprising providing a pre-formed insert. The insert may include a first pre-installation configuration including a carrier structure and an expandable material supported on the carrier structure. The insert may also include a plurality of living hinges, each hinge configured for enabling local elastic deformation of the insert in a respective pre-determined direction. The insert may also include an attachment portion and at least one contact surface located external of the expandable material for defining a generally low-friction surface as compared with the expandable material and formed for spacing the expandable material from an opposing surface during subsequent installation steps. The insert may then be attached to a first substrate. A second substrate may then be attached to the first substrate in overlying relationship with the first substrate for defining a cavity with the insert there between while elastically deforming each of the living hinges of the insert in their respective pre-determined directions so that the insert assumes a second installed configuration different from the first pre-installation configuration. The expandable material may then be activated while the insert is in the second installed configuration for causing it to foam and fill the cavity.

During the step of activating, the foam may bond to each of the first and second substrates. The insert and expandable material may provide baffling for the cavity. The insert and expandable material may provide structural reinforcement for the cavity. The method may be free of any step where the pre-formed insert returns to the first pre-installation configuration after attachment of the second substrate. One or more of the plurality of living hinges may be substantially free of any metallic component. One of the first substrate or second substrate may be in line contact with the contact surface. One of the first substrate or second substrate may be in point contact with the contact surface. One of the first substrate or second substrate may be in area contact with the contact surface. The contact surface may be a structure that is sufficiently resilient that it will resist read-through through the outer surface of the second substrate subsequent to assembly. The pre-formed insert may include at least hinges. The carrier may be defined to include a loop. At least one living hinge may open and at least one living hinge may close. The pre-installation configuration may enable clearance for installation of the second substrate so that the second substrate contacts the contact surface prior to contacting any other portion of the insert. A single point of contact may cause multiple degrees of movement of the plurality of living hinges. The insert may form into the second installed configuration as a result of the first and second surface being brought into contact with one another. The plurality of living hinges may be free of hinges that extend beyond 180°.

The present teachings provide for a movable carrier having a plurality of installation positions such that the carrier moves upon connecting a first and second surface to form a cavity about the carrier. Such movement facilitated by a plurality of living hinges.

DETAILED DESCRIPTION

This application is related to and claims the benefit of the priority date of U.S. Provisional Application Ser. Nos. 61/616,143, filed on Mar. 27, 2012, and 61/610,289, filed on Mar. 13, 2012. The entirety of these applications is hereby incorporated by reference for all purposes.

The baffle structure of the present teachings may include a carrier having one or more living hinges. The living hinges facilitate movement of at least a portion of the baffle as the shape of a cavity which the baffle is located changes during a manufacturing process. Thus, as the shape of the cavity changes, the shape of the baffle also changes to conform more precisely with the shape of the cavity. One or more hinges may include a contact surface. The contact surface may contact a wall of the cavity. The contact surface may contact a cavity wall that moves during a manufacturing process so that the movement of the cavity wall causes movement of the carrier due to the contact between the contact surface and cavity wall. The hinge including the contact surface may be the only hinge. Alternatively, the movement of the hinge including the contact surface may cause movement of one or more additional hinges.

The baffle structure may be formed in an injection molding process, which may be a two-shot injection molding process that includes a first carrier material and a second expandable material. The carrier material may include a variety of materials such as polymers, elastomers, fibrous materials (e.g., cloth or woven materials), thermoplastics, plastics, nylon, and combinations thereof. The carrier material may be fabricated from a common sheet of material to help avoid waste. The carrier material may be flexible to allow for bending of the structure to fit within desired small spaces of a cavity. As a result, during movement of any living hinge, the carrier and expandable material will also move and may therefore be formed of materials providing sufficient elasticity to allow for the requisite movement. Alternatively, the hinge portion may be substantially free of any expandable material so that only the carrier material must allow for movement.

After placement of the baffle structure into a cavity, the expandable material may expand according to a predetermined set of conditions. For example, exposure to certain levels of heat may cause the expandable material to expand. The volumetric expansion of the expandable material may vary depending upon the sealing and/or baffling needs of a particular cavity. The expandable material layer may expand at least about 100%. The expandable material may expand less than about 2000%. The expandable material may expand at least about 500%, at least about 1000%, or more. The expandable material may expand less than about 1000% or even less than about 500%. Such expansion may occur after any cavity movement that occurs during the manufacturing process. Such expansion may occur after the carrier is moved into a second installation position.

The expandable material may be generally dry to the touch or tacky and may be shaped in any form of desired pattern, placement, or thickness, but is preferably of substantially uniform thickness. Though other heat-activated materials are possible for the expandable material, a preferred heat activated material is an expandable polymer or plastic, and preferably one that is foamable. The expandable material may be a relatively high expansion foam having a polymeric formulation that includes one or more of an epoxy resin, an acetate (e.g. ethylene vinyl acetate) a thermoplastic polyether, an acrylate and/or a methacrylate (e.g., a copolymer of butyl acrylate and methyl acrylate), an epoxy/elastomer adduct, and one or more fillers (e.g., a clay filler, and/or a nanoparticle-containing filler). Preferred thermally expandable materials are disclosed in U.S. Pat. Nos. 7,313,865; 7,125,461; and 7,199,165 incorporated by reference herein for all purposes. For example, and without limitation, the expandable material may also be an EVA/rubber based material, including an ethylene copolymer or terpolymer that may possess an alpha-olefin. As a copolymer or terpolymer, the polymer is composed of two or three different monomers, i.e., small molecules with high chemical reactivity that are capable of linking up with similar molecules. Suitable expandable materials include those available from L&L Products, Inc. under the designations L7220, L2821, L1066, L205, L2010, L2105, L2108A, L2806, L2811, L4200, L4141, L4161, L4315, L5510, L5520, L5540, L5600, L5601, L7102, and L7104. The expandable material may be die cut extruded sheets of material. It may be co-extruded with the material for forming the carrier. It may injection molded with the carrier material in a two-shot injection molding process. One or more of the living hinges may include expandable material. Alternatively, one or more of the living hinges may be substantially free of any expandable material.

A number of baffling or sealing foams may also be use for the expandable material. A typical foam includes a polymeric base material, such as one or more ethylene-based polymers which, when compounded with appropriate ingredients (typically a blowing and curing agent), will expand and cure in a reliable and predictable manner upon the application of heat or the occurrence of a particular condition. From a chemical standpoint for a thermally-activated material, the expandable material is usually initially processed as a floe able material before curing, and upon curing, the material will typically cross-link making the material incapable of further flow. Curing of the expandable material may also limit the ability of any living hinge including the expandable material to move. Thus, any movement of the baffle within a cavity may occur prior to any curing of the expandable material.

In applications where the expandable material is a heat activated material, an important consideration involved with the selection and formulation of the material is the temperature at which a material cures and, if expandable, the temperature of expansion. Typically, the material becomes reactive (cures, expands or both) at higher processing temperatures, such as those encountered in an automobile assembly plant, when the material is processed along with the automobile structures at elevated temperatures or at higher applied energy levels, e.g., during coating (e.g., e-coat, paint clearcoat) curing steps. While temperatures encountered in an automobile assembly operation may be in the range of about 148.89° C. to 204.44° C. (about 300° F. to 400° F.) for body shop applications (e.g., e-coat) and, for paint shop applications, are commonly about 93.33° C. (about 200° F.) or slightly higher (e.g., 120° C.-150° C.).

The contact surface may be integrally formed of one or more of the carrier material and the expandable material. The contact surface may include portions of both the carrier material and the expandable material. The contact surface may be formed of a material that permits the contact surface to slide along the surface of a cavity wall during movement of the cavity wall. In the event that the contact surface includes any expandable material, any desired movement of the contact surface along a cavity wall may occur prior to expansion and cure of the expandable material, as such expansion and cure may prevent the contact surface from sliding along a cavity wall.

The baffle may include one or more fastening device. These devices may be formed for fastening the baffle to a cavity wall. These devices may be formed for fastening the expandable material to the carrier. Such fastening devices may be formed as a tree-fastener or a threaded screw fastener. The fastening device may also be provided in a variety of shapes and in a variety of configurations so long as it can secure the baffle to a cavity. One example of a suitable fastener is disclosed in U.S. Publication No. 2010/0021267 incorporated by reference herein for all purposes. Examples of suitable fasteners include mechanical fasteners, clips, tabs, press-fits, snap-fits, screws, hooks, combinations thereof or the like. Fastening devices for attaching the expandable material to the carrier may include slots, troughs, extension members, or any other shape that may be formed in or attached to the carrier for receiving or connecting to the expandable material. Furthermore, it is contemplated that the any fastening device may be formed integral of a singular material with the material of the baffle structure or may be formed of a different material and may be removably attached to the carrier material. The fastening device may be provided as a magnetic material or an adhesive material that can attach (e.g., adhere or magnetically secure) the baffle structure to a cavity.

The baffle structure of the present invention may be installed into an automotive vehicle although it may be employed for other articles of manufacture such as boats, buildings, furniture, storage containers or the like. The baffle structure may be used to seal and/or baffle a variety of components of an automotive vehicle including, without limitation, body components (e.g., panels), frame components (e.g., hydroformed tubes), pillar structures (e.g., A, B, C or D-pillars), bumpers, roofs, bulkheads, instrument panels, wheel wells, floor pans, door beams, hem flanges, vehicle beltline applications, doors, door sills, rockers, decklids, hoods or the like of the automotive vehicle.

Formation of the materials of the present invention may include a variety of processing steps depending on the desired configuration of the materials. Moreover, various processes such as molding (e.g., compression, injection or other molding), extrusion or the like may be used to form a carrier material and an expandable material individually and such processes may be employed to attach these materials together.

As shown for example inFIG. 1, the baffle structure (e.g., the pre-formed insert) includes a peripheral portion (e.g., a carrier)12and a plurality of living hinges14located about the peripheral portion. The carrier also includes a skid plate (e.g., a contact surface)16for contacting a surface of a cavity and preventing adhesion to the cavity and allowing the contact surface to slide along the cavity wall during movement of the cavity. As shown inFIG. 2, the baffle structure10, includes carrier12with expandable material13located thereon. A living hinge14may be formed by the carrier and the expandable material. The living hinge14may close, as shown for example inFIG. 3.

As shown inFIGS. 4A-C, the baffle structure10and carrier12are moveable during shape change of the cavity20. The living hinges14allow for flexing of the structure during movement, but also substantially prevent any spring back motion from occurring, thereby reducing the opportunity for the structure to settle in an undesired location. As shown, the location of the contact surface16moves as the shape of the cavity moves, thus allowing the shape of the structure10to move in conjunction with the cavity. The cavity20may be formed by a first substrate22and a second substrate24being brought into contact with one another. The insert10may be located into contact with the first substrate22in a first preinstallation configuration. Upon moving the second substrate24into a desired location, a first wall26of the second substrate24may contact the contact surface16and move the insert10into a second installed configuration as shown. The baffle structure may further include a fastening means (e.g., an attachment portion)18for fastening the structure to a cavity wall.

The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. The term “consisting essentially of” to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements ingredients components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, ingredients, components or steps herein also contemplates embodiments that consist essentially of the elements, ingredients, components or steps. By use of the term “may” herein, it is intended that any described attributes that “may” be included are optional.