Abstract:
An accessible bathtub apparatus for persons with disabilities, including an enclosure with an elevated bed with a seat and a foot well, a door panel, a door seal, connectors operable to pivot the door panel from an open position to a closed position, and retainers that hold the door panel in the open position until released by the user. The elevated bed allows direct lateral access by the user. The bathtub can be installed in a newly-constructed or renovated bathroom. Alternatively, it can be installed on an existing conventional bathtub, thereby avoiding the necessity of removing the old tub before installing the new one. It can be used in private homes, hotels/motels, and other locations; it can be used by persons with disabilities that would otherwise preclude them from bathing unattended or unassisted.

Description:
This application is a continuation-in-part of application Ser. No. 09/054,042, filed Apr. 2, 1998, now U.S. Pat. No. 6,151,727, which claims the benefit of U.S. provisional application Ser. No. 60/043,366, filed Apr. 2, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to bathtubs and bathtub/shower combinations that satisfy the needs of persons with temporary or permanent disabilities that render use of a conventional bathtub difficult or impossible. In particular, the present invention relates to a bathtub apparatus having a movable front panel and an elevated bed or seat, so that the bathtub can be accessed directly from a wheelchair with only lateral movement. 
     2. Discussion of Background 
     Existing bathtubs and bathtub/shower combinations come in a variety of sizes, types and configurations, ranging from older cast iron tubs that are raised on feet, to newer tubs that have oval or rounded rectangular tub recessions set into the tub structure at an angle. Some tubs have built-in Jacuzzi™ or other whirlpool units, heaters, and other devices that add to the user&#39;s comfort and enjoyment. 
     Despite the growing awareness that large numbers of people simply cannot use conventional bathroom fixtures safely (or even use them at all), essentially all present-day bathrooms contain bathtubs designed for the hypothetical “average” adult. Whatever their age or type, conventional bathtubs have raised walls that the user must step over, or steps that the user must climb in order to use the tub. Many people have temporary or permanent disabilities that render the use of a conventional bathtub difficult or impossible, even with the assistance of a nurse or other caregiver. (As used herein, the term “disability” refers to any condition, temporary or permanent, that hinders a person&#39;s access to and use of conventional bathtubs and/or showers. Such disabilities include paraplegia, missing limbs, fractures, osteoporosis, impaired balance, arthritis, multiple sclerosis, and so forth.) In the United States alone, over six million people routinely use a mobility-assisting device such as crutches, canes, wheelchairs, scooters, and the like; over four million people have difficulty taking a bath or shower; and almost three million need personal assistance in taking a bath or shower. Thus, there is a growing market for universally-accessible bathroom designs, a market that is anticipated to parallel the increase in the average age of the U.S. population and growing awareness of the needs of disabled persons and the elderly. A variety of devices are available to assist disabled persons in bathing, showering, etc., ranging from non-skid surfaces and sturdy grab bars to bath lifts, fixed or swiveling bathtub seats, and tubs with access doors. Presently-available devices include tubs with access doors such as those made by the Silcraft Corporation of Traverse City, Minn. and the Kohler Company of Kohler, Wis. 
     Bathtub devices are shown in a number of U.S. Patents, including Bourgraf, et al. (Des. 351,018) and Sween (Des. 285,346), which disclose ornamental designs for bathtubs. U.S. Pat. No. 5,701,614 issued to Appleford, et al. shows a bathtub having a side opening which extends over the full width and height of the bath and is surrounded by an outwardly and downwardly extending skirt. A door with a channel on its inner surface is upwardly translatable in its own plane to bring the door over the opening and force the skirt into sealing engagement with a seal in the channel. The seal may be a foamed rubber seal or a part fluid-filled flexible tube. 
     McAllister, et al. (U.S. Pat. No. 5,463,780 disclose a ramp which is pivotable from a generally horizontal position for elevating wheel chairs into a shower or other location to a generally vertical position which uses the ramp to hold shower curtains within the shower. The ramp has a dam which prevents water from running onto the floor. 
     Sills, et al. (U.S. Pat. No. 5,446,929) show a bath tub with a main tub body, a door support, a tambour door assembly, a door seal, and a control system. The tambour door is in a horizontal position under the floor when open and in a vertical position closing the open side of the main tub body when closed. The seal includes an inflatable tube. 
     Sween (U.S. Pat. No. 5,255,400) discloses a bathing tub apparatus that includes a tub with a sealable door, a prefillable reservoir positioned above the tub, and a support unit which includes a storage cabinet, a liquid circulation system, and a hand-held shower. The reservoir is held by the support unit. The Sween device also includes a hand held shower that may be used by the person in the tub. 
     Williams (U.S. Pat. No. 4,953,241) shows a bathtub with an entrance wall with an opening which conforms to the shape of the door, a front wall adjacent to the entrance wall, a seat located in the tub, and a locking mechanism which can secure the door in an open or closed position. The front edge of the door is attached adjacent to the front wall of the bathtub by a double axis hinge. When the door is opened, its front edge is guided directly inwardly in the tub by a tracking mechanism; the door is configured so that, during movement, it does not swing over the seat. 
     Corlew (U.S. Pat. No. 4,796,312) provides a bath tub having side walls, a rear wall, an entrance, and a door for closing the entrance. The entrance has a seal engageable with a chamfered inner surface of the door when the door is closed and water pressure is exerted on the seal. 
     Schenstrõm (U.S. Pat. No. 4,672,693) discloses a tub having an opening extending almost down to the bottom of the tub and a hatch to close the opening. The hatch is placed on the inside of the bathtub and the hydrostatic forces of the water force the hatch against the edges of the opening where a seal is provided on the hatch. 
     S Houle, et al. (U.S. Pat. No. 4,546,506) disclose a bathtub with an access opening in one side, and a vertically sliding door to close the access opening, a combination door guide and grab bar arrangement, an adjustable control console, and a power door lock which securely closes the door without significant manual effort. 
     Budlong (U.S. Pat. No. 4,034,424) provides an auxiliary bathtub mounted above a conventional bathtub, including a rectangular frame approximating the shape of a conventional bathtub and a flexible waterproof liner extending between the side and end walls of the frame and along the inside faces thereof to form a watertight container. At least one of the side walls pivots downwardly to allow entry and exit from the tub, and is held in its upright position by a releasable latching mechanism. 
     Finch, et al. (U.S. Pat. No. 3,864,762) show an elevated bathtub with a floor supported at approximately normal chair height and a side opening serving as en entryway through one of the walls of the tub. The entryway is provided with a water-tight barrier which may be moved out of the way to permit a person to enter the tub, and replaced once the person is inside the tub. 
     In addition to the above-described bathtubs, “walk-in” and “wheel-in” showers are becomingly increasingly common in hospitals, nursing homes, and even private homes designed for accessibility. However, showers cannot duplicate the therapeutic effects of soaking in a bathtub, and many people simply prefer tub baths to showers. Some estimates suggest that the United States market for accessible bathtubs could easily approach 30,000 or more per year. However, it is believed that presently available bathtub designs do not satisfactorily address the needs of the large and growing population of individuals who cannot use a conventional bathtub. 
     Many of the above-described bathtubs require more space for doors, tracks, lifts, water reservoirs, and other components than is available in typical bathrooms. Many are also complex, high-maintenance, and prohibitively expensive for all but institutional use. 
     This invention relates generally to the design and construction of bathtubs and bathtub/shower combinations, and more specifically to the design and construction of bathtubs and bathtub/shower combinations that address the unique needs of persons with disabilities. Appropriate bathtub designs for this group would not only help such persons in an important activity, but also reduce a major occupational hazard of nurses and other caregivers: sprained/strained backs and shoulders that result from assisting patients into and out of conventional bathtubs. The emphasis of the present invention is to provide a bathtub or combination bathtub/shower apparatus that people with disabilities can use to care for themselves and maintain an independent lifestyle (the terms “bathtub,” “bathtub/shower,” “bathtub apparatus” and “bathtub/shower apparatus” are used interchangeably in the following specification). 
     A bathtub apparatus that addresses these needs should have the following features: 
     1. As a baseline criterion, the bathtub must be accessible, without assistance, by a person in a wheelchair. 
     2. The bathtub should preferably be dimensioned to be comparable to a full-sized, soak-bath type bathtub, and accommodate virtually everyone (except perhaps, a small percentage of the population due to size or weight considerations). The user should be able to access and control the water temperature, flow rate, and drain. 
     3. The bathtub should be capable of being installed in a typical bathroom, either as a new installation or retrofitted to an existing unit. 
     4. The bathtub should be usable by substantially all persons. Non-disabled users (that is, those without conditions that restrict their access to conventional tubs and showers) should be able to use the bathtub to bathe and/or shower in a normal manner; disabled users should be able to bathe and/or shower with minimal risk of falling. 
     5. The bathtub must be cost-effective and easily installed. 
     Designing such a bathtub apparatus requires an understanding that, for a person with disabilities, bathing—or being bathed—involves not just the act of bathing itself (i.e., the act of immersing a person in a liquid for cleaning). It also encompasses people-handling in the psychological and physiopsychological sense: understanding and accommodating the desire for independence, dignity, safety, and security, combined in many instances with a reluctance to ask others for help. 
     In U.S. Pat. No. 6,151,727, entitled “Bathtub for Persons With Digabilities,” I disclose a bathtub apparatus with a pivotable front panel and an elevated bed that allows direct lateral access by the user (that is, a user can access the bathtub directly by stepping into the open tub, sitting on the seat and moving his or her feet into the tub, or sliding from a wheelchair to the seat). The bathtub can be installed in a new or remodeled bathroom. It can also be installed above an existing conventional bathtub, thereby avoiding the necessity of removing the old tub before installing the new one. 
     Despite the variety of presently-available bathtubs of various shapes and sizes, and of varying accessibility, there is a continuing need for a cost-effective, maximally-accessible tub which can be installed in new or existing bathrooms in residential, commercial (hotel, motel, etc.) and institutional (hospital, nursing home, assisted living facility, etc.) settings. 
     SUMMARY OF THE INVENTION 
     According to its major aspects and broadly stated, the present invention is an accessible bathtub apparatus having a floor panel, a wall panel, a movable front panel or door panel that can be opened to permit access into (and out of) the bathtub, a door seal, and pivotable connectors operable to move the door panel from a first, open position to a second, closed position. One end of the floor panel forms a stationary, raised tub bed or seat on which the user&#39;s back or buttocks rest; the other end forms a foot well. The wall panel, which is preferably integrally formed with the floor panel, may include head, rear, and foot panels (also termed “end walls”) analogous to those found in conventional bathtubs. The floor panel, the wall panel, and the movable front panel cooperate to form a liquid-containing enclosure. The apparatus, hereinafter referred to as “Alden&#39;s Tub” or the “ATI Tub,” permits direct lateral movement by the user to and from the tub bed: a nondisabled user can access the apparatus directly by stepping into the open tub; a disabled or nondisabled user can sit down on the seat and move his feet into the tub; a disabled user can slide from a wheel-chair to the seat. These modes of access are referred to herein as “direct access,” “direct lateral access,” or “direct lateral movement.” 
     The apparatus can be provided as a stand-alone model which is generally similar to a conventional bathtub/shower or bathtub/shower combination. A drop-in model which is installed in a platform base (similarly to installation of a kitchen sink in a cut-out or recess in a kitchen counter), but is otherwise similar to the stand-alone type. A portable model which can be installed on an existing conventional bathtub such as those typically found in private homes, hotel or motel rooms, and other facilities, thereby avoiding the necessity (and expense) of removing the old tub before installing the new one. The invention can be used in private homes, hotels and motels, dormitories, hospitals, nursing homes, assisted living facilities, and other locations; it can be used by persons with disabilities that would otherwise preclude them from bathing unattended or unassisted. 
     Its versatility and cost-effectiveness constitute major features of the present invention. Most bathrooms, either new or existing, have been designed to utilize either right-handed or left-handed bathtubs (i.e., bathtubs having plumbing fixtures and drainage either at the right or left side as the user faces the tub); some have centrally located plumbing. Existing bathtubs and bathtub/shower combinations come in a wide variety of sizes, types and configurations, some having built-in Jacuzzi™ or other whirlpool units, water heaters, and other devices intended to add to the user&#39;s comfort and convenience. The ATI Tub can be installed instead of another type of bathtub; alternatively, it can be retro-fitted—permanently or temporarily—to the vast majority of presently-existing bathtubs. Because the ATI Tub has no “handedness,” it can be used with either left-handed or right-handed plumbing fixtures. 
     As will be seen in the Detailed Description, the ATI Tub is simpler to manufacture and requires less materials and labor than other known designs, therefore resulting in a more cost-effective product. The ability to quickly and easily install the ATI Tub over an existing conventional bathtub reduces installation costs, since there is no need to demolish and remove the old tub before installing the new one. 
     An important feature of the present invention is the movable front, door panel which permits direct lateral access by the user. The front panel may extend the full length of the ATI Tub or only a portion of the length, and may take a number of different forms to permit it to be moveable and sealable relative to the stationary parts of the tub as will be described in detail below. 
     Depending on the needs and preferences of the user, the front panel may be bottom-hinged for a fold-up/fold down motion, side-hinged for lateral swing-out/swing-in motion, a banker&#39;s roll-top desk type of panel, a pivotable panel that pivots up or down about a pivot point away from the panel itself, or a parallelogram type panel utilizing two lever arms and pivot points at the ends of the tub. A variety of different type of seals may conveniently be used with the invention, including but not limited to compression-type seals such as are used with refrigerator doors, pneumatically-inflatable or hydraulically-inflatable seals, and diaphragm-type seals. In a preferred embodiment of the invention, the front panel is pivotable between its open and closed positions. Retainers, spring-loaded pivots, or other suitable devices hold the front panel in its open position during ingress and egress by the user. 
     Another feature of the present invention is the elevated tub bed, which is at a comfortable seating height when the bathtub is installed. Typical heights are approximately 15″-16″ (about 38-41 cm) above floor level, although heights outside this range may also be useful. This feature permits a person to move laterally to and from the ATI Tub from a wheelchair, for example, by sliding (with assistance if needed) from the wheelchair onto the tub bed. 
     Still another feature of the present invention is the foot well, which is preferably located at the same end of the ATI Tub where the water valves, nozzle, and drain would be located in a conventional bathtub. The foot well may be approximately 24″×24″ (about 61×61 cm) in horizontal dimensions and approximately 12″ (about 30 cm) deep, and serves several functions: (a) it increases the effective length of the ATI Tub for tall users so that all portions of the body, including the knees, can be submerged; and (b) it permits non-disabled users to both bathe and shower in a conventional manner. 
     Yet another feature of the present invention is the ability to fit it to an existing bathtub. Many conventional bathtubs have one or more ledges at the sides or back, together with a front wall which a user must step over to access the tub. In tubs having adequate ledges, recesses, or other structural features for support, the invention can be installed so that the enclosure rests on the ledges. Supplemental longitudinal and lateral supports, expanded plastic foam, or other devices may be used to fix it permanently in position. Alternatively, the invention may be supported by brackets attached to the existing tub and/or the surrounding walls. Pallets that interface the invention to the existing tub, filler materials, or shims may also be used where appropriate. 
     Other features and advantages of the present invention will be apparent to those skilled in the art from a careful reading of the Detailed Description of Preferred Embodiments presented below and accompanied by the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, 
     FIG. 1 is a schematic, isometric view of a portable bathtub apparatus according to a preferred embodiment of the present invention; 
     FIG. 2 is an orthographic view of the bathtub apparatus of FIG. 1, shown positioned above an existing bathtub/shower combination in preparation for installation; 
     FIG. 3 is an end elevation view of the bathtub apparatus of FIG. 1, showing the apparatus installed in an existing bathtub having front and rear ledges, wherein the apparatus is supported by such front and rear ledges; 
     FIG. 4 shows the bathtub apparatus of FIG. 1 installed in an existing bathtub, wherein a supplemental filler material is provided between the apparatus and the existing bathtub; 
     FIG. 5A is an isometric view of the off-center cam used as a pivot point for the front panel of the bathtub of FIG. 1; 
     FIGS. 5B and 5C show the cam of FIG. 5A in “closed” and “open” positions, respectively; 
     FIG. 5D shows two off-center cam pivots connected by a lever arm; 
     FIG. 6 is an isometric view of a bottom-hinged, fold-down front panel utilizing folded diaphragms for leak-proof sealing, showing the panel in the “closed” position; and 
     FIGS. 7A-E are schematic, end elevation views of moveable front panels usable with the invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the following description, reference numerals are used to identify structural elements, portions of elements, or surfaces in the drawings, as such elements, portions or surfaces may be further described or explained by the entire written specification. For consistency, whenever the same numeral is used in different drawings, it indicates the same element, portion, surface and area as when first used. As used herein, the terms “horizontal,” “vertical,” “left,” right,” “up,” “down,” as well as adjectival and adverbial derivatives thereof, refer to the relative orientation of the illustrated structure as the particular drawing figure faces the reader. It should be understood that only those components having particular functional importance or that would not otherwise be identified have been assigned reference numerals. 
     Referring now to FIG. 1, there is shown a bathtub apparatus  10  (“Alden&#39;s Tub” or “ATI Tub”) according to a preferred embodiment of the present invention. Bathtub  10  includes a wall panel  18 , and a floor panel  20  with a tub bed or seat portion  22  and a recessed foot well portion  24 . Wall  18  includes a head end wall, rear side wall, and foot end wall analogous to those found in conventional bathtub installations, being readily identifiable and therefore not numbered. 
     Foot well  24  has a drain  26 , sealable with a conventional elastomeric drain plug or some other suitable means. Tub bed  22  and foot well  24 , together with wall  18 , are stationery when bathtub  10  is installed for use, whether the installation is temporary or permanent. Tub bed  22  (and foot well  24 , if desired) may have textured surfaces for increased traction. Alternatively, textured strips or mats of non-slip material may be attached to tub bed  22  and foot well  24 . Bathtub  10  is illustrated schematically: the tub may have generally flat, rectangular walls as shown herein, or gently curved edges and surfaces to further user comfort and esthetic appeal. If desired, tub bed  22  may be contoured to form a comfortable seat for the user. 
     A pivotable door or front panel  30  is connected to the stationary portions of bathtub  10  by any suitable means, preferably by two off-center cam pivots  34  located at each end of front panel  30  as will be described further below. A seal (for example, the seal shown schematically as  28 ) seals front panel  30  to wall  18  when the panel is in a closed position. Front panel  30  may have handles, hand rails, or grab bars permanently attached thereto, such as a grab bar  32 , to assist the user in maneuvering into and out of bathtub  10 . Additional hand rails, of any convenient size and design, may be attached to the side walls and rear wall of bathtub  10 . For stability, grab bars  32  are preferably fixed in position. 
     FIG. 2 shows the bathtub of FIG. 1 suspended over a conventional bathtub or combination bathtub/shower  40  having a permanently-installed drain  42  (the water supply nozzle and valving for bathtub  40  are indicated but not numbered). It should be understood that bathtub  40  and associated plumbing are usable with the invention, but do not form part of the invention. Bathtub  10  includes pivotable front panel  30 , as well as foot well  24 , drain  26 , and the other above-described portions of the ATI Tub. 
     An optional auxiliary rear support  44  is shown schematically in FIG.  2 . Support  44  may be included when bathtub  10  cannot readily be supported in position by pre-existing bathtub ledges and the like (as shown in FIG.  3  and discussed under FIG.  4 ). 
     In use, front panel  30  of bathtub  10  is raised to the upright, “open” position shown in FIG.  1  and the user moves into the bathtub in one of several ways: with or without assistance from a nurse or other caregiver, the user moves to a sitting position with his or her buttocks resting on tub bed  22  and feet in foot well  24 . An ambulatory user may simply step into bathtub  10  and sit down on tub bed  22 . Alternatively, to minimize the risk of falling while stepping into bathtub  10 , he may sit down on tub bed  22 , swing his feet into foot well  24 , and turn so that he is facing afoot end wall  100  with his back towards a head end wall  102 . A user seated in a wheelchair pulls himself parallel to bathtub  10  at tub bed  22  facing foot end wall  100 , moves the arm rest of the wheelchair out of the way, and, holding onto the wheelchair for support if needed, slides onto tub bed  22 . Once seated on tub bed  22 , he lifts his legs (with assistance if needed), together or one at a time, into foot well  24 . Thus, tub bed  22  combines the functions of a seat and a transfer surface that a mobility-impaired person can use for entering and leaving bathtub  10 . Tub bed  22  preferably meets the ANSI (American National Standards Institute) standard for a transfer surface (i.e., at least approximately 15″ (about 38 cm) deep). 
     After the user is seated in bathtub  10 , he or she lowers front panel  30  to its closed position. Panel  30  may also include an interior handle or other device (not shown) whereby the user may open and close the panel while seated on tub bed  22  or while standing in foot well  24 . 
     Front panel  30  is then lowered and locked into its “closed” position (as indicated in FIG.  2 ), and a drain seal put into drain  26 . With front panel  30  in the closed position, front panel  30 , wall  18 , and floor  20  form a substantially water-tight (i.e., fluid-tight, liquid-tight) enclosure. Hot and cold water is introduced into bathtub  10  by means of a hose and handheld shower head or other suitable plumbing (such plumbing is not a part of this patent application). 
     Upon completion of bathing, drain  26  is opened and water from bathtub  10  drains into existing tub  40  and drain  42 . Front panel  30  is again raised. The user exits bathtub  10  by standing and moving out of the bathtub, or by sliding from seat  22  to a waiting wheelchair. If the user requires assistance, that assistance is substantially enhanced because a caregiver can quickly and easily operate front panel  30  and has ready access to the interior of bathtub  10 . For those users needing assistance to enter or leave bathtub  10 , the caregiver may be able to help the user slide onto tub bed  22  rather than having to lift him or her into the bathtub. This feature facilitates assistance by a family member, thereby delaying the necessity for hiring professional caregivers or moving to a nursing home. 
     Most existing, conventional bathtubs have a front wall which a user must step over to access the tub. Many of these bathtubs have a ledge at the opposite wall; some also have ledges at the front and/or foot end walls. Bathtub  10  can be installed in substantially all existing bathtubs, some of which may require the use of appropriate supplemental supports, expanded plastic foam, and other such devices as are known in the art. 
     For example, FIG. 3 is an end elevation view of an ATI Tub according to the present invention installed in an existing bathtub as described above, wherein bathtub  10  is shown fully inserted into the existing tub  40  and supported along its sides by a front wall  106  and a rear ledge  108  of the existing tub (for clarity, tub  40  is shown in cross-section). Pivotable front panel  30  is shown in its closed position. 
     FIG. 4 is an end elevation view of an ATI Tub with an auxiliary rear support  44  installed in an existing bathtub  40  (as in FIG. 3, tub  40  is shown in cross-section). Support  44  may be configured to provide lateral and/or longitudinal support for bathtub  10  as may be needed. Alternatively, bathtub  10  may be supported by suitable brackets attached to bathtub  40  and/or the surrounding walls. Bathtub  10  may also be partly supported by a recess or other structural feature in bathtub  40 . For some existing bathtub installations, pallets that interface the existing bathtub  40  to bathtub  10  may be provided. Such pallets would be cut to whatever size and shape may be needed. 
     In an exiting installation where there are insufficient ledges, recesses or other structural features for supporting bathtub  10  and where brackets are not feasible, a filler material or shims may need to be installed between the bed and sidewalls of tub  40  and support  44  (if present) and foot well  24  of bathtub  10 . The filler material may take any of several different forms. By way of example, thin-walled, flexible plastic sleeves may be positioned under support  44  and foot well  24 , and chemicals injected therein to form a foamed-in-place, expandable plastic filler material (indicated generally as  50 ). However, it will be understood by those of ordinary skill that other types of filler or shim may also be suitable for use with the invention. 
     When raised to an open, generally upright position, front panel  30  may be held in that position by any suitable fasteners, including but not limited to latches, clips, snaps, clamps, hooks, magnetic retainers, or other suitable devices indicated schematically as  110  (FIG.  3 ). Alternatively, at least one hydraulic or pneumatic cylinder, spiral spring, spring-loaded counterbalance, or other suitable device (indicated schematically as  112 ) may retain front panel  30  in an upright position when the panel is raised, but allow the user (or caregiver) to easily lower the panel to its closed position when desired. Where device  112  includes a counter-balance, the device may include provision for adjusting the spring tension, and optionally an adjustable stop for positively locating front panel  30  in the open position. 
     Turning now to FIGS. 5A-C, there are shown detail views of off-center cam pivot  34  of FIG.  1 . Pivot  34  includes a generally circular outer body pivot  60 , a rear plug  62 , and an off-center pivot  64  which is inserted into a suitable bushing in the wall of bathtub  10 . In a preferred embodiment of the present invention, bathtub  10  includes two such pivots  34 , one at each end of front panel  30  (as shown schematically in FIG.  5 D). A rigid operating lever arm  66  in the form of an inverted “U” connects the two pivots  34 , causing the pivots to operate essentially in unison when lever arm  66  latches or unlatches front panel  30  against bathtub  10 . However, other pivot means may also be useful for the practice of the invention. 
     FIG. 6 shows another preferred embodiment of the invention, wherein a front panel  70  is hingedly connected to the stationary portions of bathtub  10  at a lower edge  72 . Panel  70  is movable between the “open” and “closed” positions indicated in FIG.  6 . Sealing of panel  70  to bathtub  10  may be accomplished by any convenient means. By way of example, an elastomeric strip may cover the hinge, and be attached to both tub bed  22  and front panel  70 . Alternatively, folded elastomeric sheet diaphragms  74  may be connected between the front and the end walls of bathtub  10 . Latching of front panel  70  can be accomplished in a number of different ways within the spirit of the present invention. 
     FIGS. 7A-7E illustrate schematically a variety of additional front panel or door designs usable with the present invention. By way of example, FIG. 7A shows the operation of a front panel  80  that includes a rolling diaphragm-type seal. FIG. 7B shows a bottom-hinged fold-down front panel  82  such as that shown in FIG.  6 . Alternatively, front panel  82  may be side-hinged for lateral swing-out/swing-in motion if preferred. Other designs include a folding panel  84  (FIG.  7 C), a pantograph-type panel  86  (FIG.  7 D), and a two-way slide panel  88  (FIG.  7 E). 
     From the above narrative, a number of variations and alternatives may be considered as lying within the scope of the present invention. It will be clear to those skilled in the art that factors such as the particular application affect the design approach. The following discussion outlines a few of the major application factors that may impact the design approach. 
     One factor is the intended market segment for the ATI Tub. Potential markets include hotel and motel chains, retirement and assisted care homes, nursing homes and rehabilitation facilities, hospitals, and private homes. For all of these markets, the purchase of a bathtub for either permanent or temporary installation is an option, whether the bathtub is installed in a newly-designed (or remodeled) bathroom or retrofitted to an existing tub. Other options include renting or leasing a bathtub that can be temporarily installed in an existing bathroom in order to meet a short-term need. A bathtub according to the present invention can help businesses satisfy the requirements of the Americans With Disabilities Act (ADA). The ADA addresses discrimination against individuals on the basis of a physical or mental handicap; it is designed to end physical barriers in the use of public accommodations and transportation. 
     Another factor is the selection of a particular design. The ATI Tub may be provided as a “stand-alone” model with the above-described features, but which is otherwise similar to a conventional bathtub or combination bathtub/shower. This stand-alone embodiment of the invention may be permanently installable in the user&#39;s bathroom. Alternatively, the ATI Tub may take the form of a “drop-in” model which can be installed in a suitably-dimensioned recess in a platform, in a manner similar to installation of a kitchen sink in a cut-out or recess in a kitchen counter. These models, which replace a conventional bathtub installation, may be preferred for new or remodeled bathrooms designed for universal accessibility. Alternatively 
     In another embodiment of the invention, a portable model ATI Tub (such as that shown in FIG. 1) may be installed above an existing conventional bathtub such as those commonly found in private homes, hotels and motels, hospitals, nursing homes, assisted living facilities, etc. While all embodiments of the ATI Tub may be manufactured in any desired size and color, a few standard sizes are preferable from the standpoint of manufacturing and market economics. 
     A bathtub according to the present invention may be made of any suitable materials, preferably of materials that can be molded by techniques known in the art of bathtub manufacturing. Suitable techniques include spray-molding, roto-molding, blow-molding, compression molding, and injection molding. Lightweight, durable materials such as acrylic resins and other plastics, Fiberglas™, and reinforced plastics (i.e., composites composed of a thermosetting or thermoplastic resin and fibers, filaments, or whiskers of glass, metal, boron, aluminum silicate, etc.) are broadly suitable for use with the invention. 
     As noted above, a variety of movable front panels may be used with the invention, including but not limited to a bottom-hinged panel for a fold-up/fold down motion, a side-hinged panel for lateral swing-out/swing-in motion, a banker&#39;s roll-top desk type of panel, a pivoted panel permitting the movable panel to pivot up or down about a pivot point away from the panel itself, and a parallelogram-type panel utilizing two lever arms and pivot points at the ends of the bathtub. These may be used with all of the above-described models of the ATI Tub, subject to physical restrictions that may exist within any particular bathroom. 
     A variety of seals are usable with the invention, including but not limited to compression-type seals such as those used for refrigerator doors, pneumatically-inflatable or hydraulically-inflatable seals, and diaphragm-type seals. For example, diaphragm seals such as folded sheets, fan-fold sheets, or rolling diaphragm seals may be used on bottom-hinged or side-hinged panels to make the seal leak-proof. 
     Typical bathrooms are designed to utilize either right-handed or left-handed bathtubs, that is, plumbing fixtures and drainage are either at the right or left as a person faces the tub, as well as centrally located plumbing. Existing bathtubs and bathtub/shower combinations come in a variety of sizes, types and configurations, ranging from older cast iron tubs that are raised on feet, to newer tubs that have oval or rounded rectangular tub recessions set into the tub structure at an angle. The ATI Tub can be used in essentially all of the above-noted configurations, contributing to both interchangeability and economy in production. The invention has no handedness per se, thus, it can readily be installed for use with existing left-handed or right-handed plumbing fixtures. 
     A bathtub apparatus according to the present invention is believed to be simpler to manufacture, and require less materials and labor than other designs for accessible bathtubs, therefore resulting in a cost-effective product. In one embodiment of the invention, bathtub  10  can be used in place of conventional bathtubs (or bathtub/shower combinations) for new construction or renovations. In another embodiment, the portable model of the invention can be installed quickly and easily over an existing conventional bathtub. The principal advantages of portability are two-fold: the reduced costs associated with not having to remove an existing bathtub and permanently install a new tub, and the capability to quickly (and, if need be, temporarily) retrofit the ATI Tub to an existing installation. For instance, rather than remodeling an existing bathroom, a motel operator can install a portable ATI Tub in a bathroom for a customer that may only need the tub for a night or two. A homeowner can likewise install a portable ATI Tub, temporarily or permanently, for use by a resident or guest. 
     Based on assessments of existing companies that produce bathtubs for persons with disabilities, there are no known products that compete with the ATI Tub concepts, and therefore the hotel/motel, institutional (hospital, nursing home, etc.) and the private residential markets. The testing markets (hotels and motels, hospitals, nursing homes, private homes, etc.) are estimated at more than 150,000 units over a period of five years. However, the market for accessible design is anticipated to increase substantially over the coming years, paralleling the increase in the average age of the U.S. population and growing awareness of the needs of disabled persons and the elderly. 
     With respect to the above description of the invention, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
     Therefore, the foregoing description is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. Thus, it will be apparent to those skilled in the art that many changes and substitutions can be made to the preferred embodiment herein described without departing from the spirit aid scope of the present invention as defined by the appended claims.