US20080040849A1

US20080040849A1 - Bathtub liner system and method of installing a tub liner

Info

Publication number: US20080040849A1
Application number: US11/842,554
Authority: US
Inventors: John BRANDENSTEIN
Original assignee: Durotub Inc
Current assignee: Durotub Inc
Priority date: 2006-08-21
Filing date: 2007-08-21
Publication date: 2008-02-21

Abstract

The present invention is an improved system and method for installing a bathtub tub liner. The liner system can include a planar liner molded to fit the interior of the bathtub, and an adhesive to secure the liner to the tub, and a predetermined amount of water added to the tub after placing the liner in the tub to create an even amount of pressure securing the liner to the tub.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 60/823,046 filed 21 Aug. 2006, the entire contents and substance of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention is related to bathtubs and, in particular, a bathtub liner system and method of installing a tub liner, which renovates an old bathtub by laminating a tub liner to the old bathtub.
2. Description of Related Art
Bathtubs in which people bathe are made of various materials. Most bathtubs are made of cast iron, stamped steel, porcelain, fiberglass, acrylic, and the like. Due to wear and tear from usage, cleaning chemicals and the like, bathtubs deteriorate over time and tend to crack. These cracks detract from the appearance of the tubs, can spread to create a structural weakness of the tub, and can further potentially injure a bather.
Solutions to repairing cracked bathtubs vary. In some instances, urethane foam has been pumped into the cracks to improve the appearance of the tub. Unfortunately, the foam is not long lasting and the crack can resurface over time with additional wear and tear. More recently, the solution has been to place a liner over the tub. The liner can be sealed to the tub by a tape/adhesive. Yet, over time, the liner often becomes separated from the tub, and bubbles or air pockets situate between the tub and the liner creating an undesired feel and look to at least the bottom of the tub, where water can settle. A typical last resort, because of cost, is to replace the old tub with a new tub. This solution is costly, as it can require not only a whole new tub, but also additional manual labor to achieve a seamless fit between the new tub and the existing tub space. None of these solutions to cracks in bathtubs are desired, ideal or preferred.
Various U.S. patents disclose these and other solutions. For instance, U.S. Pat. No. 3,460,167 to Benjamin discloses a bathtub cover having a protective shell placed in a tub to prevent damage during construction or a renovation. Yet, Benjamin is not designed for bathing, and is not meant to be bonded to the tub it is protecting. Further, it is not custom fit to a particular make and model of a tub.
U.S. Pat. No. 4,511,621 to Thomas et al. discloses a repair laminate sheet for acrylic and fiberglass tubs. Thomas et al. discloses a pad having a fiberglass base topped with a gelcoat and plastic tread to prevent skidding. The pad is glueable to the bottom of a damaged tub bottom for reparation. The pad is not a liner, but, instead, a sheet simply glueable over faults in a tub bottom. The sheet includes a reinforcement portion for a cracked or weakened tub bottom.
U.S. Pat. No. 5,776,605 to May discloses a replacement surface and method of installation. May is not a liner, but is a pad that is used as a replacement surface for a floor or tub.
U.S. Pat. No. 5,742,955 to Parkay et al. discloses a bathtub liner apparatus that is designed to be placed into an existing bathtub. The apparatus is not designed for restoration, but simply to present a comfortable, non-skid surface. The apparatus is a removable membrane for increasing comfort and to improve the non-skid characteristics of the tub bottom.
Lastly, U.S. Pat. No. 5,560,092 to Roiger discloses a method of removing baths. The method does not enable a fit made for the make and model of the tub to be fitted. Further, it does not laminate the bottom of a liner, but is secured with foam that is designed to adhere the tub and fill empty space around a gap between the two tubs.
Therefore, it can be seen that a need exists for a superior bathtub liner and method of installing same for renovating existing bathtubs. It is to such a system, device, and method that the present invention is primarily detected.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to a bathtub liner system. The system is adapted to renovate an old, damaged bathtub by installing an exacting liner, preferably comprising acrylic, directly over the existing tub for a perfect fit. The present invention overcomes the many deficiencies of the conventional method of lining tubs (where the liner is attached to the tub with tape, that over time, cycles of flexing causes the bond to weaken, and allows water to settle underneath the bottom of the liner), by providing a permanent insert that is laminated, as opposed to taped, to the bottom of a tub, so over time, the bond between liner and tub does not weaken, and thus not room for water to settle under the liner.
Generally, conventional bathtub liners have been perceived as a good product, but for a significant weakness—they adhere to the damaged bathtub with a sticky tape commonly used to install vehicle windshields. Conventional liner solutions use an acrylic sheet that is co-extruded. The acrylic sheet is vacu-formed to create a shell of similar shape to the damaged bathtub. Then, this sheet is adhered to the damaged bathtub with the stick tape. Unfortunately, over time, the liner flexes at points of adhesion of the tape relative the tub (simply during normal use of the tub—people stepping in and out of the tub), which causes the inherently poor bond at the outset to weaken over time, ultimately allowing water to seep and settle beneath the bathtub liner.
Rather than using sticky tape to adhere the acrylic sheet to the damaged bathtub, the present invention provides a lamination process that provides a superior bond between liner and tub, effectively removing any type of uneven adhesion points, so the acrylic liner mold is laminated directly to the damaged bathtub. As a result of the lamination process, there is no space between the bathtub and the liner mold, and therefore there is no flexing in the liner or room for water to settle between the liner and damaged bathtub.
In a preferred embodiment of the present invention, a method of renovating a bathtub is provided. The method of renovating the bathtub comprises providing a sealant on at least a portion of an interior of a bathtub; providing a foam layer over at least a portion of the bottom of the interior of the bathtub; providing a tub liner over the interior of the bathtub; and providing pressure to the tub liner over a sufficient time to laminate at least a portion of the tub liner to at least a portion of the interior of the bathtub. Providing pressure to the tub liner can include at least partially filling the tub liner with a fluid. In various embodiments of the present invention, the fluid can preferably include water; the sealant can preferably include a urethane sealant; and the foam layer can preferably include open cell foam. The method can also include saturating the foam layer in epoxy. The method can further include forming the tub liner with a vacuum device.
The various aspects of the embodiments of the present invention may be more clearly understood and appreciated from a review of the following detailed description of the disclosed embodiments and by reference to the appended drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B illustrate cross-sectional views of a tub liner manufacturing process, in accordance with an exemplary embodiment of the present invention.

FIGS. 2A-2B illustrate partial cross-sectional views of the tub liner manufacturing process, in accordance with an exemplary embodiment of the present invention.

FIG. 3A illustrates a top cross-sectional view of adhesive connected to the bathtub of the tub liner system, in accordance with an exemplary embodiment of the present invention.

FIG. 3B illustrates a side, cross-sectional view of adhesive connected to the bathtub of the tub liner system, in accordance with an exemplary embodiment of the present invention.

FIGS. 4A-4B illustrate side views of the tub liner system meeting a wall for the tub liner system, in accordance with an exemplary embodiment of the present invention.

FIG. 5 illustrates a cross-sectional view of a lamination process of the tub liner system, in accordance with an exemplary embodiment of the present invention.

FIGS. 6A-6C illustrate multiple views of the drain, handles, and overflow and sealing the tub after a new liner has been installed in a damaged tub via the tub liner system, in accordance with an exemplary embodiment of the present invention.

FIG. 7 illustrates a perspective view of a bathtub for preparing a tub liner for bonding in the tub liner system, in accordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To facilitate an understanding of the principles and features of the invention, it is explained hereinafter with reference to its implementation in an illustrative embodiment. In particular, the invention is described in the context of being a bathtub liner system and method of installing the same for renovating a bathtub.
The invention, however, is not limited to its use as a bathtub liner system or method. Rather, the invention can be used when a cracked device needs repair with a liner. Thus, the liner system described can also find utility as a liner system for many applications, beyond a bathtub.
The material described hereinafter as making up the various elements of the invention are intended to be illustrative and not restrictive. Many suitable materials that would perform the same or a similar function as the materials described herein are intended to be embraced within the scope of the invention. Such other materials not described herein can include, but are not limited to, for example, materials that are developed after the time of the development of the invention.
The present invention is a tub liner system, and a method of installing the same. The tub liner system is adapted to be fittable over a damaged tub to renovate same.
The tub liner system can include at least three layers: (1) a liner; (2) a foam layer saturated in adhesive; and (3) a bottom interior of the existing tub. These three layers are in communication with one another through a lamination process. The present lamination process is possible because the weight of water applied after installation provides an equal compressive pressure to the three layers.
The tub liner system can include a planar sheet adapted to fit a tub. The planar sheet is adapted to fit the tub by being shaped from a tub mold. The tub liner system further can include foam layer sealed to the tub, and saturated with an adhesive. The tub liner can be sealed to the tub by the foam, as well as by an adhesive, if desired. By adding a predetermined amount of water to the tub, the pressure and weight of the water can evenly seal the liner to the tub.
The tub liner of the present invention preferably does not contain lead. Many enameled tubs contain lead, which are leakable into the tub water. The tub liner, not having lead, can, in effect, protect the bather from lead contamination. In addition, an optional built-in non-skid bottom increases safety. Further, a built-in guard can keep matter in the tub, and off the bathroom floor.
Liners can be made for various types of tubs. It is common that liners are manufactured for cast iron or stamped steel tubs. The structural integrity, or stiffness, of cast iron tubs of the tub mold makes it easy to vacu-form the liner, as the tub will not flex. The thin gauge metal of a steel tub, however, may not hold up to the stress of the vacuum and may buckle. This can cause the shape of the liner to become distorted. In the present invention, buckling has been solved by equalizing the pressure on all sides of the tub during the forming of the liner to the tub. Therefore, regardless of how thin the tub is, there is little to no problem with buckling.
Referring now to the figures, wherein like reference numerals represent like parts throughout, the present invention is illustrated. FIGS. 1A-1B show cross-sectional views of a tub liner manufacturing process, in accordance with an exemplary embodiment of the present invention.
FIGS. 1A-1B show a method of making a liner for a bathtub. The method used to create the liner is achieved by using a vacuum bag. The vacuum bag is large enough to surround the mold used to create the liner, and is preferably connected to the bottom of the bathtub.
Preferably, the present invention starts with a flat acrylic sheet. The sheet is heated to a desired temperature, then placed in the tub mold. The sheet is then vacu-formed to create the liner having the desired shape.
Prior to the installation of the tub liner, the overflow and drain of the tub can be removed. Eventually, after the tub liner has been fitted and installed, the drain and overflow can be replaced. Further, after the installation of the tub liner is complete, the tub is then filled with water to apply even pressure to the entirety of the bottom allowing the lamination process to occur.
One of the first steps of renovating the damaged tub includes taking measurements of the tub to be renovated. This enables identifying the make and model of the tub. Preferably, an inventory of tubs can be used such that when the make and model of the tub to be repaired is determined, the identical tub from the inventory can be used as the mode for fashioning the liner. Based on the mold, the liner can be manufactured to fit perfectly in the interior of the old tub.
A purpose of making the liner is to have a sheet 12 that will be able to properly cover the surface of the bathtub 8.
As shown in FIG. 1A, a vacuum bag 2 can be in communication with a vacuum source 1 for removing air within the bag 2. Preferably, the vacuum bag 2 is secured to the bathtub 8 by a securing mechanism 6. As one skilled in the art would appreciate, the securing mechanism 6 can be a clamp or like device. The sheet 12 can be positioned over the mold. In one embodiment, the sheet 12 is made of acrylic or plastic, and, having been heated, can be adapted to take the shape of the mold of the interior of the bathtub 8.
When the vacuum source is turned on, as shown in FIG. 1B, air is removed/sucked from the bag 2, and the sheet 12 reshaped to be flush with the inner surface of the bathtub 8. In other words, the sheet 12 is molded. Over time, pressure is equal on both sides of the sheet, so there is minimal to no strain on the interior of the tub 8.
The liner can be made from a mold made from the same make and model of bathtub 8 obtained from, for example, an inventory of bathtubs, which is used to manufacture a custom liner that will fit perfectly over the old tub.
Referring now to FIGS. 2A-2B, these figures illustrate how an apron 3 of the sheet 12 is positioned on the tub 8.
Sizing of the apron (the top ledge at the front of the tub) is an important step of the manufacturing of bathtub liners. An apron 3 of the tub 8 should be measured to a proper size. If the apron 3 is too large, it will be loose fitting, and if too small it will not fit over the existing tub. In order to allow for variations that show up in different models of the same tub, a removable apron can be used that can be adjusted for each tub during manufacturing.
A disadvantage with vacu-forming a bathtub liner is there are two planes to form which are approximately 90° apart. With the present system, both planes can be formed simultaneously. This is accomplished by bending the heated plastic sheet approximately 90° to meet the seal of the apron. This allows for tub liner forming in a single step.
Preferably, a frame 7 is positioned about the top of the tub 8 to hold the sheet 12 during a heating and molding process. The apron 3 extends over a side of the tub 8, which is preferably the side that a bather enters the tub 8. Threaded adjusters 4 are positioned over the side and over the apron 3 to hold the apron 3 in place. A front portion of the sheet can pivot approximately 90 degrees to allow the sheet 12 to seal the front of the apron 3. In the end, the apron 3 can be secured to the side of the tub 8 via the vacuum method.
FIG. 3A shows an overview placing adhesives in the bathtub before a lamination process. A urethane sealant 15, preferably 3M 5200 urethane sealant, can be placed about the interior surface (e.g., top surface and side walls of the interior) of the tub. Then, the foam layer 14, kneaded in epoxy, can be inserted therein. FIG. 3B shows the water 13 inserted into the tub after the foam layer 14 has been inserted, and after the tub liner 17 has been inserted over it. The water 13 creates uniform pressure for lamination purposes. In one embodiment, there is at least six inches of water inserted into the bathtub for this lamination process.
FIGS. 4A-4B illustrate side views showing the seal made where the urethane sealant 15 and the tub liner 17 meet a wall 18. FIG. 4A shows placing a large bead of the urethane sealant about ⅛″ from the wall 18. This is a preferred location of the placing the urethane sealant 15, as it can ensure that there is no leaking. FIG. 4B shows the tub liner 17 being placed over the urethane sealant 15, which causes same to squeeze around. Preferably, a portion of the urethane sealant 15 squeezes outside between the tub liner 17 and the wall 18 to ensure a watertight seal therebetween.
After the sheet 12 has been secured to the tub 8, preferably via sealant and a foam layer, a lamination process can occur. FIG. 5 illustrates the lamination process. A fluid 13, commonly water, is inserted into the tub 8 having the mold inserted therein. Water pressure is equal on the entire bottom 17 of the tub, which can improve adhesion of the tube liner system with the bottom 17 of the fluid filled tub 16. Located between the mold/liner 17 and the fluid filled tub 16 is a foam layer 14. In one embodiment, the foam layer 14 preferably comprises an open cell foam saturated with adhesive, such as an epoxy. This foam 14 can be used so a bottom liner 17 of the fluid filled tub 16 is permanently laminated to the original tub. By using the present tub liner and the method, space between the tub and the liner can be minimized ensuring that the bottom of the interior is firm, wherein little to no flexing of the liner can occur over time. The bonding technique used is unique to the tub repair—specifically tub liner industry. Using an open cell foam saturated with adhesive 14, the bottom of the tub liner 17 can be permanently laminated to the original tub 16. This process dramatically increases the integrity of the installation and also gives the bather a secure feeling in the bottom of the tub. This solid bottom is not achieved with conventional installation methods.
The lamination process is enhanced by using the substantial weight of a full tub of water to apply equal pressure over the entire bottom.
In a preferred embodiment, the tub liner includes an acrylic finish, making the tub tough, easy to clean, and giving a glossy look of porcelain. Further, thermal properties of the liner enable bathwater to stay warmer longer.
FIGS. 6A-6C illustrate placing a gasket 19 between the tub and the plumbing pipe. Specifically, FIG. 6A illustrates a side, partial cross-sectional view of a drain 20, while FIG. 6B illustrates a perspective view of the drain 20. The gasket 19 is positioned between the tub and the plumbing pipe, not between the liner and the tube. A portion of the gasket 19 can be reamed out for securing devices, such as screws. Furthermore, some urethane sealant 15 can be applied around the circumference of the overflow and drain and the tub and the liner. FIG. 6C illustrates that plumbers putty can be applied beneath the overflow drain 21.
FIG. 7 illustrates the completed tub liner installed over a damaged tub that has been renovated. The corners 25 are preferably rounded to prevent damage to the walls 18. Further the tub liner is cut to a proper depth to ensure that it does not prevent from compression when filled with water for lamination.
While it will be understood by those of skill in the art that the following very specific details regarding a preferred installation can be modified without departing from the general inventiveness, of the present invention, the installation process of the tub liner can generally include the following steps:
First, remove the caulk and excess grout around the top and front sides of tub, and clean out soap scum, preferably by using ethyl alcohol. Then, remove both the overflow and drain from the tub.
Second, measure the dimensions of the tub before cutting the tub liner. The width of the back wall, the height of the tub, the front of the apron, and along the floor should be measured. These measurements can be made with a tape measure, or like measurement tool. The left, center, and right of the tub should also be measured. Preferably, a half inch (½″) is added to the measurement of the apron measurement, in order to have enough liner material for the apron.
Third, set spreaders up against the tile, or wall, and tighten down securing devices, such as screws, to get a pattern of the surrounding wall to enable a proper fit of the liner. Then, bring it up flush to wall, but do not tighten the screws too much, just enough to form a snug fit against the tile.
Fourth, adjust nylon backstops for liner.
Fifth, align the template to the liner, which is preferably sitting on the cutting table, and cut off the excess with a jigsaw.
Sixth, before a test fit of the liner, round off the corners of the liner to prevent damaging the wall or tile.
Seventh, test fit the tub. It is preferable that the liner fits comfortably without pressure points on the wall.
Eighth, cut two cross braces from scrap plastic. These will be used to apply pressure to sides of liner after tub is bonded in place.
Ninth, position a protector against wall opposite the drain. Pick up the liner with the drain hole down, and set the liner into the tub with drain end going down first. Pull the tub liner out past the soap-dish, if present, and fan the outside apron out to get the liner in the tub. Next, remove the liner and make several cuts before a proper fit will be obtained.
Tenth, form the drain hole. Place a heat protector pad with hole over drain area heat and form drain.
Eleventh, return the liner back to the cutting table, and cut out the overflow and drain holes. Then, smooth edges of drain and overflow holes with sandpaper.
Twelfth, rough up underside of liner with 36 or 60 grit sand paper, and wipe down entire underside with alcohol, preferably, ethyl alcohol.
Thirteenth, place the foam layer on the interior bottom of the tub.
Fourteenth, cut off at least six pieces of excess foam and save same for placing on top of the apron. The extra foam can be saturated in epoxy, and be placed on top of the tub apron. Cut the back part of the pad about 3″ short to allow stretching. Also, cut a hole in foam pad for the drain.
Fifteenth, test fit the liner before using the Whirl-A-Way. Using the Whirl-A-Way, strip paint down to the metal on the top along the tiles, around the drain and overflow, in a V-shaped pattern around the inside of the tub and the complete bottom of tub.
Sixteenth, scrape the remaining paint off the top edge of the tub. Then, wipe down with ethyl alcohol.
Seventeenth, mix the two part epoxy (preferred ratio is two parts resin (20 to 24 oz)) to one part hardener (10 to 14 oz) and pour onto the foam pad. Knead it in until it is saturated. Make sure there are no dry spots in the foam pad, because a dry spot can form a hollow spot that could cause a crack to form. Also, saturate the six pieces that go under the drip guard at the same time.
Eighteenth, apply sealants—preferably using a total of three tubes of 3M 5200 sealant—liberally around the top edge of the tub on the four sides of the bathtub. It is preferred that at least one full tube is used next to the tile. This can enable a solid seal and adhesion when the liner is pressed down. Apply two caulk lines around drain and overflow. On the outside face of the tub, run a bead down the front at each end. Save a portion of last tube for overflow.
Nineteenth, cut and stack small epoxy saturated pads and place on top of the apron (FIG. 3A). Set in liner drain end first and then press down the liner. Keep the liner as level as possible. Do not allow drain end to scrape up 3M 5200 as the back end of the tub liner is slid down.
Twentieth, place one or two drain gaskets around drain between flanged waste piping and tub, as needed.
Twenty-first, apply plumbers putty around waste drain, and screw back in. Tighten it snugly and give it about a half turn. Verify that liner is bottomed out against tub.
Twenty-second, fill the tub with water to approximately two inches below overflow plate. Take two braces made from scrap plastic and put a folded paper towel to protect surface of liner on each end. Press in on the sides of tub so that it will help the liner adhere to the sides.
Twenty-third, use Naptha to clean off excess urethane sealant around liner and tile that has squeezed out.
Twenty-fourth, run a bead of silicone caulk around the outside edge of the liner. Do one wall at a time to allow smoothing before it sets up.
In conclusion, the high precision of this manufacturing liner, along with an installation process enables the manufacturing of a bathtub liner integral and permanent with the existing tub, producing superior to taped liners over the conventional methods.
The presently disclosed embodiments are, therefore, considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.

Claims

1. A method of renovating a bathtub having an interior with a bottom, the method comprising:

providing a sealant on at least a portion of an interior of a bathtub;

providing a foam layer over at least a portion of the bottom of the interior of the bathtub;

providing a tub liner over the interior of the bathtub; and

providing pressure to the tub liner over a sufficient time to laminate at least a portion of the tub liner to at least a portion of the interior of the bathtub.

2. The method of claim 1, wherein providing pressure to the tub liner comprises at least partially filling the tub liner with a fluid.

3. The method of claim 2, the fluid comprising water.

4. The method of claim 1, the sealant comprising a urethane sealant.

5. The method of claim 1, the foam layer comprising open cell foam.

6. The method of claim 5, further comprising saturating the foam layer in epoxy.

7. The method of claim 5, further comprising forming the tub liner with a vacuum device.

8. A method of renovating a bathtub, the bathtub having an interior with a bottom and sides for containing water, the method comprising:

inserting a layer of sealant on a portion of the interior of the bathtub;

inserting a open cell foam layer saturated in epoxy over a portion of the bottom the interior of the bathtub;

inserting a molded acrylic sheet over the bottom and sides of the interior of the bathtub;

filling the bathtub with at least six inches of water; and

laminating the molded acrylic sheet to the interior of the bathtub.

9. The method of claim 8, the sealant comprising a urethane sealant.

10. The method of claim 8 further comprising forming the tub liner with a vacuum device.