Two-piece head restraint and method for making same

A head restraint comprising a first core portion including an exterior surface, an interior and a perimeter edge between the exterior surface and the interior, a first outer layer provided about at least a region of said exterior surface of said first core portion, a second core portion including an exterior surface, an interior and a perimeter edge between the exterior surface and the interior, and a second outer layer provided about at least a region of said exterior surface of said second core portion, wherein at least a region of the perimeter edge of the first core portion is attached to at least a region of the perimeter edge of the second core portion to define a perimeter seam therebetween.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is generally related to a head restraint, and in particular to an open style head restraint with a closeout for both aesthetic and/or structural purposes, and a method for making same.

2. Description of the Related Art

Recent legislation has required vehicle seat head restraints to extend higher in vehicles for improved safety. For example, European legislation requires that the top of the head restraint be positioned 750 mm above the hip pivot point, which is substantially higher than most current designs. As a result of these tall seat designs, either the seat back is made taller and/or the head restraint is made taller. Because a taller seat back may obstruct the view of the occupant, it is preferred that the head restraint is made taller and includes a halo or opening to maximize visibility.

With a taller or larger head restraint design made of a foam filler material, the overall weight of the head restraint increases, thereby reducing fuel economy of the vehicle. In addition, a taller or larger head restraint design imposes design constraints, such as a stitch seam for the covering material.

The inventors of the present invention has recognized these and other problems associated with conventional head restraint designs and have developed a two-piece head restraint design that reduces the overall weight of the head restraint, while improving visibility, impact properties, and increasing the modularity of the design.

SUMMARY OF THE INVENTION

A head restraint comprising a first core portion including an exterior surface, an interior and a perimeter edge between the exterior surface and the interior, a first outer layer provided about at least a region of said exterior surface of said first core portion, a second core portion including an exterior surface, an interior and a perimeter edge between the exterior surface and the interior, and a second outer layer provided about at least a region of said exterior surface of said second core portion, wherein at least a region of the perimeter edge of the first core portion is attached to at least a region of the perimeter edge of the second core portion to define a perimeter seam therebetween.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now toFIGS. 1 and 2, a head restraint10is shown according to an embodiment of the invention. The head restraint10comprises a first portion, shown generally at12, and a second portion, shown generally at14that are pre-formed prior to being attached to each other. One or both of the first and second portions12,14may include a cover material16for providing an aesthetically pleasing appearance (Class “A” surface) to the head restraint10. Alternatively, the cover material16can be omitted and the outer surfaces of the first and/or second portions12,14may provide an aesthetically pleasing appearance (Class “A” surface) by using spray skin process.

One aspect of the invention is that one or both of the first and second portions12,14is made of core material18having energy absorbing properties while providing a dimensionally stable surface. For example, the core material18may comprise an expanded polypropylene (EPP) foam material, or the like. The EPP foam material is lighter in weight than conventional materials, such as a foam filler core material. In addition, the density of the EPP foam material is directly proportional to the pressure at which the EPP foam material is injected into the mold tool. For example, a higher injection pressure produces a higher density EPP foam material, as compared to a lower injection pressure. Thus, the density of the EPP foam material can be selected to provide improved energy absorbing properties, as compared to conventional foam filler materials. Further, the EPP foam material can have a non-uniform density throughout the head restraint10by selecting the pressure at which the core material18is injected into the mold tool. For example, the core material18can have a lower density at the outer surface of the head restraint10, and can have a higher density at the center of the head restraint10, or vice versa.

As shown inFIG. 2, one or both of the first and second portions12,14can be formed to include a cavity20that is adapted for receiving and securing a head restraint post22in place. The size of the cavity20can be such that the post22is press fit into the cavity20. Alternatively, one or both of the first and second portions12,14may include a relatively softer material, rather than including the cavity20, for securing the post22in place. The relatively softer EPP foam material can be injected into the mold tool using a two-shot injection molding operation in which the first shot of injected EPP foam material is set before injecting the second shot of material.

Once the post22is secured in place, the first and second portions12,14can be attached to each other using a variety of different means, and the invention is not limited by the means for attaching the first and second portion12,14to each other. For example, the first and second portions12,14can be attached using a tongue and groove arrangement24of a type well-known in the art. The tongue and groove arrangement24provides a means for mechanically interlocking and securely attaching the first and second portions12,14to each other. It will be appreciated that other conventional means for attaching the first and second portions12,14to each other are within the scope of the invention.

Once the first and second portions12,14are attached to each other, the head restraint10forms a seam25between the first and second portions12,14. Unlike conventional head restraints in which the seam is sewn by a separate operation, the seam18of the invention can be formed by using an edge wrapping technique to provide a clean, neat and precise appearance for the head restraint10.

Once the cover material16is wrapped around the edge26, the first and second portions12,14can be placed in a bond tool that applies heat to the first and second portions12,14. While in a slightly molted state, the first and second portions12,14are pressed together to bond the first and second portions12,14together. The first and second portions12,14can be heated using any suitable means, such as ultrasonic welding, or the like. Alternatively, the first and second portions12,14can be bonded to each other using any suitable means, such as by applying an adhesive to the first portion12and/or the second portion14, the cover material16, or any combination thereof. It will be appreciated that the invention is not limited by the means for bonding the first and second portions12,14to each other, and that the invention can be practiced by using any suitable means, such as a mechanical fastener, vacuum or bladder bonding, or the like.

After the first and second portions12,14are attached together, any excess cover material16can be trimmed by transferring the heat restraint10to a trim tool. The trimming of any excess cover material16can be accomplished by various means, such as laser cutting, hand trimming, hard tool, water jetting, or the like.

After any excess cover material16is trimmed, the head restraint10can be transferred to an assembly tool where all designed components, such as the posts22, are placed into the head restraint10. As shown inFIGS. 3aand3b, one or both of the first and second portions12,14may include one or more engineered areas28when in an unfolded state. An adhesive30is then applied within each engineered area28and the first and/or second portion12,14is folded to form the final surface shape for the portion12,14.

Referring now toFIG. 4, a head restraint40is shown according to an alternate embodiment of the invention in which the cover material16is used as a hinge32to form a “clam shell” design.

Other designs for the head restraint10are contemplated by the inventors and are within the scope of the invention. For example, the principles of the invention can be applied to a “halo” style head restraint design, as shown inFIGS. 5 and 6. As used herein, the “halo” is defined by the central opening of the doughnut-shaped head restraint10.

For a “halo” style head restraint design as shown inFIG. 5, a head restraint50of the invention may include a closeout52made of a mesh or net material that is disposed in an opening defined by first and second core portions. The first and second core portions each include secondary edges54,56that define a secondary seam. However, it will be appreciated that the invention is not limited by the material used for the closeout52, and that the invention can be practiced by using a closeout52made of any desired material. For example, the closeout52may be made of a cellular material as shown in the illustrated embodiment, such as a net, mesh, or the like. Alternatively, the closeout52may be made of a non-cellular or substantially solid material, such as a plastic, fiberglass, or the like. For safety, the closeout52may add structural integrity to the head restraint50for absorbing energy during impact. In addition, the closeout52may have a “see-through” property to allow the occupant to have a substantially unobstructed view through the halo of the head restraint50.

Unlike conventional “halo” style head restraint designs, the “halo” style head restraint50of the invention does not suffer from leakage associated with the conventional foam materials used to form the head restraint. In the invention, the EPP foam material is cured prior to application of the posts22that are used in the invention.

However, the invention is not limited to a “halo” style head restraint design as shown inFIG. 5. For example, as shown inFIG. 6, the invention can be practiced with a head restraint60in which an opening is formed between a pair of upright posts62without a top and/or bottom member connecting the posts62of the head restraint60together to form a “horse shoe” and/or a “goal post” head restraint design.

Other alternate embodiments of the invention are contemplated by the inventors and within the scope of the invention. For example, an optional mold-release coat may be applied to each of the mold surfaces (not shown). For brevity, the mold-release coat can be to be applied to only one mold surface. The purpose of the mold-release coat is to promote efficient removal of the head restraint10,50,60from the mold assembly (not shown) after the forming process is complete.

Then, an optional in-mold coat can be applied to the mold-release coat on each of the mold surfaces when the mold assembly is placed in the open position. The in-mold coat is preferably applied in a generally uniform manner to promote consistent gloss, texture, and color of the outer contour of the head restraint10,50,60. Preferably, the in-mold coat is a waterborne urethane coating, which can be applied by an air-atomized coating applicator such as a spray gun or bell applicator. Alternatively, the composition and means of applying the in-mold coat may be of any suitable type.

Next, a skin coat is applied to the in-mold coat in a manner similar to application of the in-mold coat. The composition of the skin coat is preferably a two component polyurethane elastomer including a polyol component and an isocyanate component as disclosed and described in U.S. Pat. No. 5,885,662 which is incorporated herein by reference in its entirety. The in-mold coat, which is applied to each mold half bonds to the respective skin coat to form a structural skin. Depending on the formulation of the skin coat, the in-mold coat can be eliminated from the process.

Once the mold-release coat, the in-mold coat and skin coat are applied, the mold assembly is then placed in the closed position. Before the mold halves are moved to the closed position, the coats are preferably allowed to at least partially harden to a non-liquid or gel state. Once the mold halves have reached, or just prior to reaching, the closed position, the mold halves can be mechanically clamped or locked together to ensure that the mold assembly is properly placed and held in the closed position.

When in the closed position, the coats of the first mold half bond with the coats of the second mold half at the junction between the mold halves. That is, the portion of the coats around the perimeter of the first mold surface bond with the portion of the coats around the perimeter of the second mold surface. The bond between the coats of the mold halves is more durable than a conventional head restraint having sewn seams because the bonding of the subject invention is particularly resistant to tearing, ripping, snagging and opening during repeated use over the life of the head restraint10,50,60.

The EPP foam material18is then injected into one of the mold cavities. After being injected, the EPP foam material18expands in the mold cavity and bonds with the structural skin, formed by the coats to form the head restraint10,50,60. The EPP foam material18may be manufactured of a color that is complementary to the color of the structural skin, which provides the advantage of partially concealing any tears, cuts or breakage in the structural skin that may occur during the life of the head restraint.

The EPP foam material18is allowed to expand in the mold cavity and partially cure. The EPP foam material18is injected into the other mold cavity and allowed to expand and partially cure. While the EPP foam material18in both mold cavities are in the partially cured condition, the posts22placed within the groove20and the mold halves are closed. When the EPP foam material18is cured, the mold halves are opened to remove the completed head restraint10,50,60.