US20030200606A1

US20030200606A1 - Reinforcement structure for a molded article

Info

Publication number: US20030200606A1
Application number: US10/134,423
Authority: US
Inventors: Gerard Bellasalma
Original assignee: Masco Corp
Current assignee: Masco Corp
Priority date: 2002-04-29
Filing date: 2002-04-29
Publication date: 2003-10-30

Abstract

The invention is a molded article having a reinforcement structure disposed therein. A settable mixture preferably including a catalyst, a matrix polymer, and a foaming agent introduced into a mold forms the shape of the molded article. The molded article includes a base section having a first thickness and wall sections extending upwardly about a periphery of the base section. The base section is substantially thicker than the wall sections. The reinforcement structure is disposed within the base section to reduce the amount of settable material required to form the base section and maintain the structural strength of the molded article.

Description

BACKGROUND OF THE INVENTION

This invention relates to a reinforcement structure for a molded article. Many types of molded articles are fabricated by mixing at least two hardenable or settable fluid materials in a low pressure mold. Typically, bathtubs and one-piece bathtub shower combinations are formed using this type of molding operation. The fluid materials most often include a three-part mixture that takes the shape of the mold after setting for a curing period. Typically, the three-part mixture includes a catalyst, a matrix polymer and a foaming agent.

A molded article such as a bathtub is typically composed of different sections. Preferably, a bathtub molded from the three part mixture requires that the lower section or bottom have an increased thickness relative to the other sections of the bathtub in order to support the total weight of the bathtub, water in the tub and an occupant. However, the three-part mixture is costly and any means to decrease the volume of mixture required to provide a structurally sound molded article would greatly decrease the cost of manufacture. Further, the process of molding a large molded article such as a bathtub is time consuming, and any method found that could reduce the curing time of the three part mixture would also be beneficial.

For these reasons it is desirable to develop an assembly and method of molding an article from a mixture that would provide the required structural strength and reduce the volume of three-part material required such that the material cost and the time to produce the molded article is reduced.

SUMMARY OF THE INVENTION

The invention is a molded article having a reinforcement structure disposed in a thickness such that the quantity of molding material is reduced while maintaining the required structural strength.

The molded article is fabricated from at least two fluid materials combined to form a settable mixture. Preferably the settable mixture includes a catalyst, a matrix polymer and a foaming agent. The molded article is preferably a bathtub including a base section having a first thickness and wall sections extending about a periphery of the base section. A reinforcement structure is disposed within the base section such that the volume of the settable material required to form the base section is substantially reduced by an amount equal to the volume of the reinforcement structure.

The subject invention also includes a method of forming a bathtub fabricated from the settable mixture. The method includes placing the reinforcement structure within the mold and injecting settable material into the mold and around the reinforcement structure such that the volume of settable material required to fill the section containing the reinforcement structure is reduced.

The subject invention provides an assembly and method of molding an article from a mixture that provides the required structural strength and reduces the volume of the three part material required, thereby reducing material costs and production cycle time.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows: [0008]
FIG. 1 is perspective view of a molded bathtub having a reinforcement structure; and [0009]
FIG. 2 is a cross sectional view of the bathtub and the position of the reinforcement structure; and [0010]
FIG. 3 is a perspective view of the bathtub with a plurality of reinforcement structures.[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, the subject invention is a molded article generally shown at [0012] 10 in FIG. 1. Preferably the molded article 10 is a bathtub fabricated from at least two fluid materials combined to form a settable mixture. Preferably the settable mixture will include a catalyst, a matrix polymer, and foaming agent. The settable mixture is injected into a mold 12 (FIG. 2) having a cavity 14 shaped to form the molded article 10.
Referring to FIGS. 2 and 3, the bathtub includes a [0013] base section 16 having a first thickness 18 that supports the bathtub and anything within the bathtub. A wall section 20 extends about a periphery of the base section 16 and is of a second thickness 22 that is preferably thinner than the first thickness 18 of the base section 16. The specific structure of the bathtub may be of any configuration recognized by a worker knowledgeable in the art.
A [0014] reinforcement structure 24 positioned within the first thickness 18 of the base section 16, occupies a volume that would otherwise be filled with the settable material. Because the reinforcement structure 24 occupies a volume in the thicker base section 16, a lesser volume of settable material is required to form the base section 16 while increasing the required structural strength. Preferably, the reinforcement structure substantially reduces the volume of settable material required in the base section 16 and thereby reduces the cost of manufacture. Further, a lesser volume of settable material would require less curing time and thereby lessen the cycle time required to fabricate one molded article 10.
The [0015] reinforcement structure 24 is preferably located in the base section 16 because this is the thickest section of the molded article 10. However, it should be understood that the reinforcement structure 24 may be placed within the molded article 10 in any section of the molded article 10 were it is desirable to reduce the volume of settable material.
Referring to FIG. 2, at least one [0016] support 26 affixed to the reinforcement structure 34 supports and positions the reinforcement structure 24 within the mold 12 at a desired location within the first thickness 18 of the base section 16 prior to plastic injection. The supports 26 are preferably fabricated from the same settable material used to form the molded article 10. The supports are preferably pre-molded from the same settable material such that the supports are attachable to the reinforcement structure by fasteners such as nails, staples or the like. The settable material of the supports 26 will bond and intermix with the settable material during molding, thereby avoiding the need for any type of extraneous support mechanism to position and support the reinforcement structure 24. The placement and number of supports 26 are determined only by the need and the desired position of the reinforcement structure 24 in the completed molded article 10. A worker knowledgeable in the art would recognize that the placement and number of supports 26 would vary depending on the specific shape to be molded. Of course, other ways of supporting a structure within a mold can be used.
In the preferred embodiment shown in FIG. 1, the reinforcement structure is positioned longitudinally within the thickness of the [0017] base section 16. The position of the reinforcement structure 24 may be disposed in any desired direction. The specific position and direction of the reinforcement structure 24 may be determined as required for each specific application as known by a worker knowledgeable in the art. Referring to FIG. 3, a plurality of separate reinforcement structures 26 can be used and placed throughout the molded article 10 as required and determined by a worker knowledgeable in the art.
The [0018] reinforcement structure 26 is fabricated from any type of material compatible with the settable material. Preferably, the reinforcement structure is a rigid material. It should be understood that the reinforcement structure 26 can be fabricated from any wood, paper, or from material that would not adversely react to the settable mixture. Most preferably, particle bond may be used.
Referring to FIGS. 1 and 2, the molded [0019] article 10 with the reinforcement structure 26 is fabricated by a method including the steps of providing a mold 12 to form the shape of a molded article 10, placing a reinforcement structure 24 within the mold 12 in the base section 16 such that the reinforcement structure 24 reduces the amount of matrix required to fill the base section 16. The reinforcement structure 24 is positioned within the mold 12 by way of the supports 26 fabricated from the same settable mixture used to form the molded article 10. As noted above, a plurality of reinforcement structures 24 may be utilized depending on the specific application and structure of the molded article 10. A settable material is introduced into the mold 10 in a substantially liquid form and cured for a specified time. The completed molded article 10 is then removed from the mold 12.
The foregoing description is exemplary and not just a material specification. The invention has been described in an illustrative manner, and should be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications are within the scope of this invention. It is understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention. [0020]

Claims

What is claimed is:

1. A molded article fabricated from at least two fluid materials which are combined to form a settable mixture, said molded article comprising;

a first section; and

a structure disposed within said first section to displace a quantity of the settable material.

2. The assembly of claim 1, wherein said structure includes at least one support to position said reinforcement structure within said first section.

3. The assembly of claim 2, wherein said supports are fabricated from the same settable matrix used to form said molded article.

4. The assembly of claim 1, wherein said structure includes a reinforcement structure.

5. The assembly of claim 1, wherein said reinforcement structure is positioned longitudinally within said first section.

6. The assembly of claim 1, where said molded article is a bathtub.

7. The assembly of claim 1, wherein said structure is fabricated from a wood material.

8. The assembly of claim 1, wherein said structure is fabricated from particle bond.

9. The assembly of claim 1, wherein a plurality of said structures are located within said first section.

10. A bathtub fabricated from at least two fluid materials which are combined to form a settable mixture, said molded article comprising;

a base section having a first thickness;

a wall section extending from said base section and having a second thickness thinner than said first thickness; and

a reinforcement structure disposed within said base section to displace a quantity of the settable material required to form said base section, said reinforcement structure includes a plurality of supports to position said structure within said thickness of said base section.

11. The assembly of claim 10, wherein said supports are fabricated from the same settable matrix used to form said bathtub.

12. The assembly of claim 11, wherein said reinforcement structure is positioned longitudinally within said base section.

13. The assembly of claim 11, wherein a plurality of said reinforcement structures are positioned within said base section.

14. A method of forming a molded article fabricated from at least two fluid materials which are combined to form a settable mixture having a first section and a second section, said method includes the steps of:

a. providing a mold to form a molded article;

b. placing the reinforcement structure within the mold such that the reinforcement structure reduces the amount of settable material required to fill the mold;

c. introducing the settable mixture into the mold in a substantially liquid form;

d. curing the settable mixture such that the reinforcement structure is contained substantially within the molded article.

15. The method according to claim 14, further including the step of supporting said reinforcement structure within the mold by a plurality of supports.

16. The method according to claim 15, wherein said supports are pre-molded from the settable material and attached to said reinforcement structure.

17. The method according to claim 14, wherein said reinforcement structure is arranged longitudinally in the thickness of the second section.

18. The method according to claim 14, wherein a plurality of reinforcement structures are mounted to the reinforcement structure prior to said step b.