KR101450027B1 - System and method of forming variable density seating materials - Google Patents

Abstract

The present invention generally relates to systems and methods for forming a sheeting material having a variable density gradient and more particularly to the formation of a foam material for vehicle seats having variable density gradients that allows for greater comfort over a wide range of occupant weights , And the use of single-foam formulations over a wide variety of vehicle seats has significantly different performance characteristics.

Description

TECHNICAL FIELD [0001] The present invention relates to a system and an apparatus for forming a variable density sheeting material,

This PCT application claims the benefit of U.S. Provisional Patent Application No. 61 / 363,820, filed July 13, 2010, entitled "SYSTEMS AND APPARATUS FOR FORMING A VARIANT DENSITY SITING MATERIAL," the entire disclosure of which is incorporated herein by reference Which is incorporated by reference in its entirety.

1. Field of the Invention

The present invention relates generally to systems and methods for forming a sheeting material having a variable density gradient and more particularly to a system and method for forming a sheeting material having a variable density gradient for vehicle seats having a variable density gradient that allows for greater comfort over a wide range of occupant weights. Relates to the formation of foam materials and the use of single foam formulations over a wide variety of vehicle seats has certain significantly different performance characteristics.

2. Related Technology

Vehicle manufacturers must create comfortable vehicle seats for a wide range of vehicle occupants with significantly different weights and sizes. The manufacturer of the vehicle seat should consider the weight range from the weight range of a child no longer requiring a booster seat to a heavier and larger range of adults. Lighter passengers and heavier passengers may find that the same vehicle seat performs a significantly different function, and each passenger prefers a very different strength and more specific flexibility to the seating material. For example, the static comfort of a seating foam, such as a polyurethane seating foam, is highly dependent on the strength and density of the foam, particularly the high flexibility. Vehicle builders attempt to select the strength of the foam to provide the desired static comfort for a wide range of occupant weights, but the difference between the weight of the occupant and the amount of flexure associated with the occupant's sinking into the foam while sitting on the seat It is difficult to please all the passengers. In particular, flexible foam materials are easy to provide a comfortable seat for lightweight occupants, while most weight occupants feel floor, frame feel, or inconvenience in the same seat. Conversely, rigid foam materials are generally a comfortable seat material for heavy occupants, but also result in less flexure, which is too rigid for lightweight occupants, so that a lightweight occupant sits on top of the foam and at least partially sinks inside the foam I feel uncomfortable. Although manufacturers can adjust the strength of the foam to the desired strength for the average user, the more the vehicle occupant is displaced due to the weight of the average user, the less comfortable they are from these vehicle seats. Thus, for single-piece foam sheet constructions, manufacturers have historically limited their ability to provide a comfortable seating surface for a wide range of occupant weights.

The change in comfort of the seating materials or the desired performance of the seating materials may also be highly dependent on the desired application, vehicle type, target customer, and vehicle manufacturer preference. For example, in many sports cars or performance cars, it is desirable to have a seat that is more rigid than a luxury car.

Essentially, to address the different seating characteristics and in particular the demands on the strength of the foam, most manufacturers have formed a variety of foam formulations. These different foam formulations have made it possible to address changes in the properties of particular sheets, but have not addressed any of the aforementioned problems associated with differences between the occupants of the vehicle seats. In addition, the increased comfort and increased durability as well as the requirement for extended ranges of required properties limit the ability of manufacturers to address all desirable properties by merely modifying the foam formulation. In addition, as the required traits, the desire for high intensities for some individuals and the range of desire for low intensities for some different individuals, have been raised, problems with this inconsistent comfort have arisen, Are not chemically well balanced with conventional foam formulations, thereby causing difficulties during the manufacturing process. Most of these unique foam formulations that require special chemicals require additional fabrication facilities and processes that increase the cost of natural materials and sometimes increase the cost of vehicle seats.

In order to address the aforementioned drawbacks and the wider weight range of vehicle occupants, some manufacturers have formed a foam assembly of two parts for the seating material, but this requires time consuming and expensive fabrication processes. Therefore, due to the cost of assembling multiple slabs made of foam with different densities, their application across a wide range of vehicle seats is currently limited. The sheet material of both fuels can generally be formed by two methods. First, applying a soft layer of a separate foam to a rigid molding foam wherein the soft slab of foam is in close proximity to the A-surface or seating surface of the sheet material. In such a manner of forming the foam sheeting material of the two parts, the hard foam sheet material is first molded and then the second soft sheet material is molded into the desired shape or cut from the slabstock foam. The two parts are then bonded together by an adhesive, but this increases the manufacturing cost significantly because of the labor, equipment, materials and space required. The use of adhesives to bond soft die-cut slabstock forms or separate molding pieces to rigid molding foams is generally preferred because manufacturers also strive to improve the environmental aspects of the fabrication process as well as the recycling aspects of materials not. For example, in the use of two-part seating material, it is difficult to find an eco-friendly adhesive that can make it difficult to recycle the sheet at the end of its life cycle and has desirable performance characteristics throughout the life cycle of the sheet.

Also, a second method developed by some seating makers is a mold-in process for forming a seating material of two parts, eliminating the need for adhesives. Although the need for adhesives has been eliminated, significant drawbacks that significantly slow down the line speed and processing time for each of the sheeting materials also occur in the molding process. In particular, many fabrication uses a foam making method that pours multiple formulations into one layer, typically in multiple layers, to achieve high strength bolsters while maintaining a soft insert near the A surface. The additional agents and processing steps require additional space for storing the different components used in the mold, and the space for such additional equipment results in additional demands on the operators of the manufacturing process. In addition, no suitable technique for preventing the contamination of the mold-in slab from the liquid polyurethane chemical mixture being mixed during the foaming process has been found to date. More specifically, the different layers of the foam each have uncontrolled or undesirable mixing, or the boundaries are placed outside of their preferred layer, such as where the flexible foam formulation penetrates into the desired areas of the hard foam formulation, and further The bad thing is that sometimes only partial infiltration causes a non-uniform feeling of strength and a hard spot in the vehicle seat. While many fabrication processes have controlled the injection processes in an attempt to overcome such quality problems, this sometimes adds complexity and limits the type of formulations that can be used to increase the cost of the fabrication process and sometimes to one another. This contamination and mixing of the formulations negates the benefit of the comfort found in providing a seating slab, typically of two slab-molded part materials.

Other problems occur with vehicle seats using backing materials such as placing a material such as a pre-cut cloth in the mold and then molding the foam directly onto the material. While these methods are typically used to fabricate strong B surface bonds for increased durability as well as other performance properties, it is difficult to use them in multi-foam formulations as well as in the mold-in-process of the two components described above. More specifically, molding the backing material in the mold can cause a number of problems during foam molding processes, such as the undesirable mixing of various types of materials as well as the movement of the backing material when multiple layers are being injected.

The present invention is generally directed to a system and method for forming a sheeting material having a variable density gradient for a high intensity ratio of high-to-low deflection. More particularly, to forming a foam material for a vehicle seat having a variable density gradient that allows for greater comfort over a wide range of occupant weights.

The present invention employs a method of forming a variable strength sheeting material while preventing a minimum of tooling changes and a reduction in fabrication efficiency. First, the material is placed in a mold and then expanded to fill the mold. Unlike conventional molds, the present invention uses molds with larger cavity areas where variable plates or mold sections are placed. When the mold cavities are filled with the expanded foam and reach the hardened state, the movable member compresses the sheet to its final size such that the regions closest to the movable member are compressed and have a greater density. This forms a variable density sheet having a greater strength difference between low and high bends. Such a seat foam is more comfortable for a wide range of occupant weights by being flexed favorably to light weight passengers while providing sufficient support for heavy occupants to prevent the sensation known as "bottoming out" .

Various exemplary embodiments of systems and methods according to the present disclosure will be described in detail with reference to the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a drawing showing an exemplary seating mold having an A surface that is the initial position and bottom side of the mold material after the mold of the present invention is closed,
Fig. 2 is a view of the mold of Fig. 1 having a movable member in a first position and a foam seaming material extending to completely fill the mold cavity,
Figure 3 is a view of the mold of Figure 2 in which the movable member for compressing the sheeting material is moved from a first position to a second position to provide an increasing density gradient illustrated on the backside of the sheeting material,
4 is a diagram showing an exemplary graph of deformation (in mm) versus force applied to the sheeting material of the present invention, as compared to a variation of a conventional sheeting material,
5 is an exemplary graph of transmittance versus frequency using the same formulation, density, and thickness, with the same formulation, density, and thickness,
Figure 6 is a graph of curvature vs. strength for the same formulation, thickness, and weight,
Fig. 7 is an exemplary graph of the load curve versus curvature versus load, and in particular is a plot showing a similar load curve obtained using a conventional foam with a foam of 96 mm and 1,220 g, of only 70 mm and 1,096 g; to be.

The present invention generally relates to a system and method for forming a sheet (not shown). Such a seat generally includes a seating material that provides a vehicle occupant with a support, such as the illustrated foam base 10. The foam base 10 includes an A surface 12, a back surface 13, and a bolster 18. 3, the cross-sectional view shows a density gradient zone 14 having a high density zone 15 and a low density zone 16 in the final foam base 10 configuration.

The sheet, specifically the foam base 10, is typically formed in a mold. Although the sheet material, particularly the foam base 10, can be formed in any style, size, or configuration, the figures illustrate exemplary sheets and the present invention may be applied to other styles and configurations. In addition to the illustrated foam base 10, the mold 20 can also be modified in style, shape, size, and configuration if desired to form a particularly desirable seating material. The mold 20 generally includes a base portion 24 and sidewalls 26, and within the sidewall the foam material may be laid to begin the mold process. The depicted mold 20 generally includes a bolster cavity 28 and a main cavity 30 defined by the sidewalls 26, the base 24 and the top plate 32 being the movable member . As shown in FIG. 2, the top plate 32 may have a first or retracted position 34 and a second or extended position 36 as further shown in FIG. The illustrated mold 20 is intended to form the base 10 of the sheet and may be used for other styles, shapes, sizes and configurations of other molds, as well as for the upper back of the seat, Different molds required for the materials can be used. Also, although not shown, other portions of the mold may include additional movable members to alter the density of other portions of the sheet, such as movable members within the bolster section (not shown), to provide different densities in the bolster zone.

The present invention, particularly the process of forming a sheet, is similar to other sheet forming processes in that the mold is opened and the mold material, such as a polyurethane, which sits the foam initial material, is placed or inserted into the mold in the desired amount and then the mold is closed Start. Molds depending on the type of material used can be preheated to the desired temperature before the material is placed inside the mold. The material 11 may be any type of material usually used or may be desirable for use in forming a seating structure. As shown in Figure 4, the present invention compares a conventional polyurethane foam sheet base with a polyurethane foam sheet base incorporated in the present invention. In the case of a polyurethane foam material 11 placed in a mold in a desired amount, the process of expanding the foam to fill the mold begins as shown in Fig. More specifically, in Fig. 2 the material fills the mold and reaches the semi-cured state and allows it to remain in the mold without modification for some additional specified period of time. The mold 20 of the present invention includes an enlarged cavity area, such as the illustrated main cavity 30, where the foam at its initial position as shown in FIG. 2 is in contact with the end sheet base 10, Lt; RTI ID = 0.0 > a < / RTI > When the mold material completely fills the mold cavity 30 for a desired period of time, the inner top plate 32 is moved from a first position as shown in Fig. 2 to a second position as shown in Fig. Upon movement of the top plate 32 to the second position 36, the mold cavity forms the final desired shape and size for the seat base 10. 3, by moving the top plate 32 from the first position 34 to the second position 36, the region closest to the top plate 32 of the foam base 10 is moved to the highest density zone < RTI ID = 0.0 > (15). By comparison, the lowest density zone 16 is the approximately A-surface 12 that is furthest away from the top plate 32 and joined against the A-mold surface 24. The density of the foam in the main cavity 30 can be changed to a gradual uniform density gradient, but the increase in density is expected to be more acute rather than linear. More specifically, the lower density zones 16 extend further into the foam base 10, and as the zones reach the back surface 13, their density quickly increases substantially to a higher density zone. As shown in FIG. 4, the present invention allows low strength at low flexing and then increases in strength at a higher rate than conventional sheet foam, with increased flexing. As shown in Figure 4, the present invention removes expensive two-part foam sheet material while providing better static comfort for a wide range of occupant weights. In addition, the present invention uses less material and can only reduce the overall weight by providing high density to only those sections that are needed.

The mold 20 also includes a special foam base 10 of only one style, or other zones including movable members in addition to or in addition to the top plate shown, Other styles may also be used in which the density gradient can be further adjusted to a particular sheet style, shape, or configuration that allows for < RTI ID = 0.0 > For example, the cavity of the bolster cavity 28 may include a movable bolster plate (not shown) to intentionally expand and to increase the density on the outer interface of the bolster to provide more support as needed.

Also, for a mold, such as forming a top back of a sheet material to provide comfort along a complete top back, the movable member may not have uniform compression along the length of the top back (not shown). It is therefore desirable to form various density gradients where it is desirable to increase the comfort of seating through the use of multiple plates across the surface. (Not shown) that is provided with a foam base 10 (not shown), which is compressed to provide a larger cavity near the back surface of the sheet than the front edge of the sheet, and thereafter the density gradient between the back of the foam base and the front of the foam base, Other examples for the same seating base may be provided.

The front with a smaller weight placed by the legs may have a softer and more comfortable sitting position and the seat will allow greater support to the foam base where the largest weight is placed by a particular user. This will increase the comfort of seating and reduce the fatigue of the vehicle operator.

It is important to note that in Figure 7 both mass and thickness provide a reduction in vehicle weight and provide increased interior space.

Since the foregoing invention has been described in accordance with the relevant legal standards, the description is illustrative rather than limiting in nature. Modifications and variations on the described embodiments will be apparent to those skilled in the art and are intended to be within the scope of the present invention.

Claims (15)

As a method for forming a seat cushion,
Providing a non-cured foam material;
Providing a mold having two or more mold members that cooperate to form a mold cavity, wherein one of the two or more mold members is a one extending from a retracted position to an extended position in the mold cavity The movable member reducing the volume of the mold cavity at the extended position;
Inserting the uncured foam material within the mold cavity;
Causing the uncured foam material to be partially cured to an intermediate state;
Moving the at least one movable member to the extended position to form a density gradient in the foam material intermediate, wherein the mold surface of the movable member at the extended position is engaged with the intermediate, uncured foam member engaging the at least one movable member;
Curing the intermediate state uncured foam material to a final state; And
And removing the seat cushion formed of the foam material in a final state.
A method of forming a seat cushion.
The method according to claim 1,
Moving the at least one movable member to form a density gradient includes forming a variable density gradient in the intermediate, uncured foam,
Wherein the foam material joined by the movable member at the extended position has a low density area that extends further into the foam material than a high density area and the density of the foam material increases as the density approaches a high density area, (Exponentially increasing)
A method of forming a seat cushion.
The method according to claim 1,
Wherein providing the uncured foam material comprises: inserting the uncured foam material into a portion of a mold cavity formed by one of the mold members; And closing the mold halves to form the mold cavity including the uncured foam material.
A method of forming a seat cushion.
The method of claim 3,
Wherein inserting the uncured foam material into a portion of the mold cavity further comprises providing a uniform foam material.
A method of forming a seat cushion.
The method according to claim 1,
Wherein at least one of the mold members does not include a movable member,
Wherein inserting the uncured foam material further comprises inserting the uncured foam material into a mold member having no movable member,
A method of forming a seat cushion.
The method according to claim 1,
Wherein the movable member is not engaged with the uncured foam material in the retracted position,
A method of forming a seat cushion.
The method according to claim 1,
The step of partially curing the uncured foam material to an intermediate state further comprises applying heat for a certain amount of time.
A method of forming a seat cushion.
The method according to claim 1,
The step of partially curing the uncured foam material to an intermediate state further comprises inflating the uncured foam material to at least contact the movable member in an intermediate state,
Wherein the non-cured foam material does not come into contact with the movable member when it is first placed in the mold member,
A method of forming a seat cushion.
The method according to claim 1,
The step of moving the at least one movable member further comprises forming a density gradient in the foam material,
Wherein the foam material proximate the at least one movable member has the highest density region,
A method of forming a seat cushion.
The method according to claim 1,
Wherein the step of curing the intermediate state uncured foam material to a final state further comprises maintaining the movable member in an extended state,
A method of forming a seat cushion.
The method according to claim 1,
Wherein the step of causing the intermediate state uncured foam material to cure to a final state further comprises retracting the movable member to a position between the extended position and the retracted position,
A method of forming a seat cushion.
The method according to claim 1,
Wherein the step of partially curing the uncured foam material to an intermediate state comprises causing the uncured foam material to fill the mold cavity.
A method of forming a seat cushion.
13. The method of claim 12,
Moving the at least one movable member to the extended position such that the mold surface of the movable member at the extended position engages the uncured foam member in the intermediate state, And reducing the volume of the mold cavity when the at least one movable member is moved to the extended position,
The seat cushion having a volume equal to the reduced volume of the mold cavity,
A method of forming a seat cushion.
As a seat cushion,
A foam material having an outer surface having a first surface and an opposing second surface,
Wherein the foam material has a variable density gradient between the first surface and the second surface,
Wherein the foam material has a greater density at the second surface than at the first surface,
The seat cushion includes:
Providing a non-cured foam material;
Providing a mold having two or more mold members cooperating to form a mold cavity, wherein one of the two or more mold members includes at least one movable member capable of extending from a retracted position to an extended position in the mold cavity The movable member decreasing the volume of the mold cavity at the extended position;
Inserting the uncured foam material into the mold cavity;
Causing the uncured foam material to be partially cured to an intermediate state;
Moving the at least one movable member to the extended position, wherein the mold surface of the movable member at the extended position engages the non-cured foam member in the intermediate state;
Curing the intermediate state uncured foam material to a final state; And
And removing the seat cushion formed of the foam material in a final state,
Seat cushion.
15. The method of claim 14,
Wherein the density gradient changes exponentially between the first surface and the second surface,
Seat cushion.

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