Patent Application
20080164730
1. Field of the Invention
The invention relates to vehicle head restraints.
2. Background Art
Head restraints for vehicle seats are utilized for providing comfort to an occupant and also for the safety of the occupant. For example, in the occurrence of a rear impact, the occupant's head impacts the head restraint. Thus, safety and comfort are design considerations that are factored concurrently.
Vehicle head restraints often include a head restraint bun, which provides the structural support to the occupant's head in both the impact conditions and ordinary operations. In order to provide comfort to the occupant, the head restraint bun typically includes a layer of soft foam for padded comfort.
In recent years, a cost effective design that optimizes both structure and comfort has been employed in some head restraints in European vehicle seats, which utilize an expanded foam insert within the head restraint bun. The insert is commonly made of an expandable structural foam that is subsequently covered with a soft foam layer for providing comfort.
In Dec. 22, 2004, the National Highway Traffic Safety Administration of the United States Department of Transportation released a new Laboratory Test Procedure for Federal Motor Vehicle Safety Standard (FMVSS) 202aS, that includes “backset retention” and “height retention” requirements. The backset retention and height retention requirements limit the energy absorption of the head restraint.
One embodiment of the invention provides an insert for a head restraint for a vehicle seat with a body formed from a structural material. The body is sized to be inserted within a foam layer of a head restraint bun. The body is adapted to be mounted to a seat back of a vehicle seat. The body has a head contact surface for receiving a head of an occupant. The body has a central depression formed in the head contact surface for providing an increased contact area to the head of the occupant.
Another embodiment of the present invention is an insert for a head restraint for a vehicle seat with a body formed from a structural material. The body is sized to be inserted within a foam layer of a head restraint bun. The body has a front head contact surface for receiving a head of an occupant. The body has a recess formed in a rearside of the body opposed from the head contact surface. The recess has a transverse region for receiving a transverse portion of an armature, which is inclined in a forward direction for retention of the armature during occupant imparted loads from the forward or rearward directions.
Another embodiment of the present invention is a method for forming a head restraint. The method includes molding a head restraint insert from a structural material with a head contact surface and a depression in the head contact surface for providing an area of contact to a head of an occupant, and with a forward inclined recess in a back surface of the insert for retaining the insert upon an armature. A tubular armature is formed and inserted into the recess. A soft foam is insert-molded about the head restraint insert and a portion of the armature.
The above embodiments and other embodiments, advantages, benefits, features, aspects, and objects of the invention are apparent in the attached figures and in the detailed description of embodiments of the invention below.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to variously employ the present invention.
Referring now to
Referring now to
The head restraint 16 includes an insert 24 mounted to the armature 22. The insert is formed from a rigid or impact absorbent material for absorbing an impact imparted upon the insert 24 by, for example, the head of the occupant. In at least one embodiment, the impact absorbent material is a foam. Expandable polypropylene is a suitable foam for fabricating the insert 24, for example. The expanded polypropylene may be provided with a density of forty-five to sixty kilograms per cubic meter, to provide a light and cost effective insert that is suitable for the applicable design requirements. In at least another embodiment, the insert is formed from expandable polystyrene. In yet another embodiment, the insert is fabricated from polyurethane foam. In at least another embodiment, the insert is formed from blow-molded plastic. Of course other suitable materials are contemplated within the spirit and scope of the invention.
The head restraint 16 of the depicted embodiment also includes a soft outer foam layer 26 that is molded about the insert 24 and a portion of the armature 22. In one embodiment, the soft outer foam layer 26 collectively forms a head restraint bun with the insert 24. The foam outer layer 26 is illustrated fragmented in
Referring now to
The insert 24 has a generally planar forward facing head contact surface 28 and an upward facing head contact surface 30. During an impact condition, the occupant's head compresses the foam outer layer 26 and then impacts the insert 24 at one of the head contact surfaces 28, 30. An occupant's head is typically round and therefore to provide an increased contact area to the head of the occupant, a central depression 32 is formed within the forward contact surface 28. Likewise, a central depression 34 is formed within the upward contact surface 30. The depressions 32, 34 are arcuate and recessed within the respective contact surfaces 28, 30 to provide an increased contact area to the head of the occupant. By providing an increased contact area rather than a point contact, the load of the impact is distributed over a larger area resulting in less displacement or deformation to the contacting surfaces of the insert 24. The reduced displacement to the insert 24 results in less damage to material of the insert 24.
The insert 24 has a width, which is the lateral dimension along the forward contact surface 28. The insert 24 also has a height, which is the upright dimension of the forward contact surface 28. To accommodate occupants of varying height, and/or to accommodate various height adjustments of the head restraint 16, the central depression 32 bisects the width of the insert 24 and extends along the height. Thus, the forward depression 32 is a cylindrical depression along the centerline of the depicted insert 24 embodiment. Likewise, the upward contact surface 30 has a thickness provided in a fore/aft dimension of the insert 24. The upward depression 34 bisects the width of the upward contact surface 30 and extends along the thickness to provide the area of contact along upward contact surface 30. The upward depression 34 is also cylindrical in at least one embodiment and is formed along the centerline of the upward contact surface 30.
The insert 24 of the depicted embodiment withstands the height retention and backset retention tests of the FMVSS 202aS of Dec. 22, 2004, which is incorporated in its entirety by reference herein, without necessitating an increased density and cost of the insert 24. Flat contact surfaces without depressions result in undesirable displacement when subjected to these tests. The increased contact areas provided by the depressions 32, 34 of the insert 24, distribute the load, resulting in improved performance and reduced displacement values within the limitations set by the height retention and backset retention tests. One suitable dimension for withstanding these tests is that the depressions 32, 34 may be provided with a radius of eighty-two and one half millimeters. Although one exemplary dimension is provided other suitable dimensions are contemplated within the spirit and scope of the present invention.
Referring now to
Referring now to
Referring now to
During insertion of the armature 22 into the trench 36, which is illustrated by the armature transverse portion 44 in phantom (pre-insertion) and the armature transverse portion 44 in solid (inserted), the interference projection 41 provides a substantially increased retention between the insert 24 and the armature 22 in the installed position. This retention prevents dislodging of the insert 24 from the armature 22 when a forward force is applied at the top/rear region of the head restraint 16. In another embodiment, a net fit is provided at the installed position, with interference at intermediate positions during assembly, thereby preventing disassembly.
The transverse region of the trench 36 is inclined in a forward direction. Upon application of a load to the insert 24, such as by the head of the occupant, in a rearward direction, the trench 36 maintains the retention of the insert 24 upon the armature 22. Likewise, application of a load in a forward direction, such as a load imparted from a rear passenger during ingress and egress does not disengage the insert 24 from the armature 22. Such a load is applied generally at the top of the head restraint 16 above the incline of the trench 36 so that the trench 36 retains the insert 24 upon the armature 22. Locating the retaining projection 41 at the top and rear of the trench 36 with the incline provides sufficient retention of the insert upon the armature in a cost-effective manner.
Moreover, a low cost and lightweight insert 24 for a head restraint is provided that withstands applicable testing and mounts and retains the insert 24 to the armature 22 without requiring additional components, such as fasteners, adhesives or the like that would add to the cost and weight of the head restraint 16.
In one embodiment, the insert is molded from an expandable foam with the contact surfaces 28, 30, the depressions 32, 34 and the trench 36 molded into the body of the insert 24. The armature 22 is formed from a tube that is bent, cold formed or otherwise shaped to mount the insert 24 and foam outer layer 26 to the seat back assembly 14. The armature 22 is inserted into the trench 36 of the insert 24. Due to the interference fit of the trench 36, the armature 22 must be pressed into the trench 36 in one embodiment. Subsequently, the insert 24 and a portion of the armature 22 are disposed within a mold and the foam outer layer 26 is molded about the insert 24 thereby collectively providing the head restraint bun for the head restraint 16.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
