Bathing Access Device for Disabled Persons and Method of Using the Same FIELD OF THE INVENTION

This invention relates generally to the field of mobility aids for people with disabilities, who have restrictions in their ability to move. In particular, this invention relates to mobility aids of the type that can be used by people with physical disabilities to help them to get over a bathtub or into a shower stall. Usually, with this type of equipment, the person with the physical disability is being assisted by a caregiver.

BACKGROUND OF THE INVENTION

People can suffer a loss of mobility for a number of reasons including spinal cord injuries, sickness, old age, or other infirmities. The loss of mobility can be of varying degrees. People who have lost mobility need to rely on assistive devices for such disabled persons to be able to perform normal activities of daily living functions, including toileting, washing and bathing unless they are getting bathed in bed (bed baths) by a caregiver. Most individuals would prefer to bathe either in a shower stall or tub. However, access to a bathing area may be difficult due to the design of normal bathing facilities, such as the side wall of a bathtub or the curb around a shower stall, which can act as barriers to wheel chairs or other rolling aids used by persons with physical disabilities. In some cases, tubs are removed and replaced with roll-in showers. In other cases, shower stalls are made accessible by removing the curbs. In these cases, the preferred method of accessing the shower area is a wheeled shower chair. In other cases, there may be a lack of financial resources or in the case of a rental home, apartment or condominium unit, lack of permission to replace the bathtub with an accessible roll in shower or bathing facility. What is desired is a mobility aid or access device to allow the mobility restricted person to overcome the barriers present in a conventional bathroom area to allow the person comfortable and reliable access to a bathing area, such as a shower or bath tub.

One possible solution has been proposed in U.S. Patent No. 7,690,055 to Hammer et. al. This patent describes a portable bath transfer system that provides a person with a physical disability access to non-accessible bathroom facilities without having to rely on mechanical lifts. The patent describes using a chair portion, a connector bridge portion, and a bathtub portion. The chair portion includes a base section with two or more support members and an upper chassis section including a backrest, a chair seat, and armrests. The connector bridge portion includes connecting members attached by a cross member. The bathtub portion includes a base and four adjustable support members that provide increased stability and fine adjustment capability to match the chair portion height. The bath transfer system includes an interlocking system for the bridge including a continuous groove and lipped brackets to prevent the upper chassis section from tipping or lifting, and anti- roll mechanisms and a volitional latch to prevent undesired sliding of the upper chassis.

Although providing a reasonable solution for some cases, the invention described has certain disadvantages. In particular, the bridge portion must be removed from between the bath portion and the mobile seat base portion and then rested on the floor beside the tub, when bathing or showering commences to provide unfettered access for the caregiver who will be bathing the person. Also, when bathing using a hand shower, it is sometimes necessary to draw the shower curtain at least partially. With the bridge portion connected to the bathtub portion, the shower curtain cannot be drawn because the bridge extends over the tub wall. The bridge portion must be disconnected at both ends from the respective bases and leaned up against the side of the tub or the like as shown in the Figure 11c of Patent 7,690,055. This creates the risk that the separated bridge portion could fall or slip away out of reach when detached. Drawing such a shower curtain closed to contain the spray can accidentally dislodge the bridge element from its resting place. As well, the bridge portion as taught in this prior patent requires that both ends be attached and unattached, which requires that the tub portion, bridge and chair portion be aligned with sufficient precision that the connections of the bridge to the tub and chair portions can be made. A slight misalignment of the tracks due to uneven heights or angular misalignment can make achieving the connection difficult. What is desired is an improved design which overcomes these and other disadvantages of this prior invention.

United States Patent No. 7,506,385 teaches a different design, but in this design the bridge portion is left in place extending out across the side of the bathtub from the mobile base even once the stationary base is disconnected. The bridge section will then be in the way of a shower curtain or shower door. Movement of the mobile base off its starting position will make reconnection and alignment more difficult. It may be therefore that this design is only suitable for circumstances where the shower curtain or door is not closed.

Several other prior mobility aids to assist in bathing are also known, such as the following:

United States Patent No. 5,373,591

United States Patent No. 5,517,704

However, these fail to cure the deficiencies of the 7,690,055 patent and the 7,506,385 patent as discussed above.

SUMMARY OF THE INVENTION

What is desired is a mobility aid for a mobility restricted bather, having for example, a mobile base to enable the bather to be positioned adjacent to a bathing area when seated on said mobile base, and a movable seat to support the mobility restricted bather, the movable seat being releasably attached to said mobile base. When released the movable seat may be moveable along a translation axis and into a bathing area, by means of trucks attached to an underside of the movable seat to permit the seat to roll along a track. The trucks may include low friction sliders or rollers extending laterally from both an inside edge and an outside edge on an axis perpendicular to the translation axis. A stationary bath base is provided for placement in the bathing area and for supporting the movable seat in the bathing area. An extendable bridge is provided, which extends and retracts from the stationary base, and can releasably connect the mobile base to said stationary or bath base so the movable seat may be moved along the connected bridge between said mobile base and said bath base in either direction along said translation axis.

The mobile base, the extendable bridge and the stationary bath base may form, among them, a discontinuous overlapping track support for guiding and supporting said rollers of the trucks under the movable seat. In a preferred embodiment the discontinuous track may be located on one side of the trucks on said mobility base and said stationary bath base and on the other side of said trucks on said bridge. In one embodiment, the tracks may be on the outside on each of the bases and on the inside on the extendable bridge. In another embodiment the tracks may be stacked one above the other, but this stacked embodiment is less preferred due to seat height issues. The discontinuous track sections may overlap end to end, so that the opposed rollers or wheels from a truck engage tracks on both sides of the truck before disengaging from one track. In this manner the trucks may at some transition locations to be supported by both tracks before being then supported by only one track on each side. In this way, the trucks are supported by the mobility base tracks only when on the mobility base, by the extendable bridge tracks as the seat is moved along the bridge and away from the mobility base and then by transitioning from the bridge tracks to the stationary base tracks as the seat is positioned over the stationary base. The longitudinal overlapping of the tracks allows the transition from the bridge to the stationary base to be smooth and gradual as there is no abutting track section to have to pass the rollers over. In a preferred embodiment the tracks on the bridge may be positioned slightly lower that the tracks on the stationary base to permit the bridge to be freely telescoped in and out even with the seat positioned over the stationary base, because the bridge tracks will not be load bearing with the seat over the stationary base.

The bridge portion may be made extendible out from the stationary base by a low friction combination such as rollers or simple sliders in combination with a track profile and a latch can be used to lock the free end of the bridge in place to the mobility base. Although the description refers to the bridge being mounted in the stationary base it will be appreciated that the present invention comprehends that it could also be mounted and extendible from the mobile base. However, this may be less preferred as it would have to be mounted around the bed pan of the commode chair. Once the seat has traversed onto the stationary base the bridge lock can be undone and the bridge can be easily retracted back into the stationary base providing unfettered access for the caregiver and allowing the shower curtain to be closed. The bridge track can be positioned so that it is not load bearing when the seat portion is located fully on the stationary base. It can now be appreciated that the user or attendant can easily pull the bridge into or out of the stationary base with one hand for example. In this way, the bridge is always at hand and there is no requirement to reach for a fallen bridge section to reattach the bridge between the bases. In some cases, the attendant will not be able to let go of the disabled person, for fear of them falling for example, and the convenient location of the sliding bridge, stored under the disabled person, means that they don't have to. Because the bridge is retractable, it requires alignment and connection at one end only, to the mobile chair base, unlike other designs that require alignment and connection to both the tub base and mobile base. In a preferred embodiment the mobility base will include four swivel wheels and once the bridge is extended the mobility based can be easily manipulated into position relative to the bridge to allow the bridge lock to then be employed.

In a preferred embodiment, the extendible bridge is permanently attached to the stationary base and only releasably attached to the mobile base. In this way, the bridge is always at hand and need not be detached and set down, potentially out of reach, when bathing or showering is taking place. Because the present invention stores the bridge on the stationary base under the user when not needed during bathing, it is readily at hand and easily accessible when the bathing or showering is finished. Further, because the bridge can be extended only as much as needed to a position to be locked to the mobile base the single telescoping bridge of the present invention may comprehend various sizes of working spaces, which may be defined by the presence of toilets or other immovable objects in the washing area, thus eliminating the need for separately sized (and priced) bridge sections for various situations.

The present invention may also include a primary safety system to ensure that the sliding seat and disabled person supported thereon are safely latched in position unless and until the bridge is safely extended and secured and in some cases may include a secondary safety system to ensure that the seat is not moveable until the caregiver has released a secondary safety latch.

According to one embodiment, the present invention provides a bathing assist system for a disabled bather, the system comprising:

a mobile base to enable the bather to be positioned adjacent to a bathing area when seated on said mobile base; a stationary bath base for placement in said bathing area;

an extendible bridge permanently mounted to said stationary base for releasably connecting said mobile base to said bath base; and a movable seat to support the mobility restricted bather, the movable seat being releasably attached to said mobile base, said movable seat being moveable between said mobile base and said stationary base along said bridge; said movable seat further including at least three trucks attached to said movable seat, each truck including rollers extending laterally from said trucks on an axis generally perpendicular to an extension axis of said bridge,

wherein said mobile base, said bridge and said stationary bath base form a discontinuous overlapping track for supporting said rollers of said movable seat, wherein different portions of said discontinuous track support different rollers as said seat moves between said mobile base and said stationary base.

According to a further embodiment, the present invention provides a method of transferring a disabled person into and out of a bathing area, said method comprising the steps of:

securing a stationary base in the bathing area,

positioning a mobile base outside of said bathing area adjacent to said stationary base,

drawing an extendible bridge out from said stationary base and securing the same to said mobile base to form a connected structure, sliding a moveable seat along said bridge from a first position on said mobile base to a second position on said stationary base,

disconnecting and retracting said extendible bridge while said moveable seat is located on said stationary base, and

permitting the disabled person to bath. According to a further embodiment of the present invention, there is provided a safety latch system for an assembly including a bath base, a mobile base, an extendible bridge and a seat which can be moved from one base to the other across the extendible bridge, the safety latch system comprising:

a first bridge element which is moveable between a first position and a second position;

a second bridge element which is moveable between a first position and a second position;

a first arm to move said first bridge element between said first and second positions according to whether said bridge element is locked onto an adjacent base;

a second arm to move said second bridge element between said first and second positions according to whether said bridge element is locked onto an adjacent base; and

safety latches carried by said seat whereby said safety latches are sized, shaped and positioned to move between a locking position and an open position as said first and second bridge elements are moved between said first and second positions.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made by way of example only to preferred embodiments of the invention by reference to the following drawing in which:

Figure 1 is an assembly view of a mobility aid according to one embodiment of the present invention showing a mobile base, a bridge, a sliding seat and a stationary base, having a tilting seat;

Figure 2 is a view of a mobile base having tracks for the sliding seat according to the present invention; Figure 3 is a view of a stationary base with tracks for the sliding seat but without the attached extendible bridge for ease of illustration according to an aspect of the present invention;

Figure 4 is a view of the bridge having tracks for the sliding seat but separate from the stationary base for ease of illustration according to the present invention;

Figure 5 is a view of the stationary base and the bridge attached together in the normal configuration of this embodiment of the present invention;

Figure 6 is a close up of the rear sliders for the bridge of Figure 5 according to one aspect of the present invention;

Figure 7 is a close up of the front sliders for the bridge of Figure 5 according to one aspect of the present invention;

Figure 8 is one embodiment of a rolling or sliding seat according to one aspect of the present invention showing the trucks for rolling the sliding seat along the tracks;

Figure 9 is a close up of the truck wheels in the tracks;

Figure 10 is a second embodiment of a rolling or sliding seat according to the present invention;

Figure 11 is a close up of the wheels of the trucks for the seat of Figure

10 in supporting tracks;

Figure 12 is a view from above of a mobility aid according to the present invention illustrating the transition from load bearing on the outside, to the inside, and then to the outside wheels of the truck as the rolling seat is translated between one base and the other according to the present invention;

Figure 13 is an assembly view of a mobility aid according to a further embodiment of the present invention showing a mobile base, a bridge, a translating seat and a stationary base, in an embodiment having a having a non-tilting seat; Figure 14 is a perspective view of the bridge extended from the stationary base according to one aspect of the present invention;

Figure 15 is a view of the free end of the bridge being docked into the mobility base of the present invention;

Figure 16 is a view of the locking lever and loop engaging the mobile base docking the bridge to the mobile base with some elements removed for clarity according to an aspect of the present invention;

Figure 17 is a view illustrating one embodiment of a safety latch release trigger associated with said docking mechanism of Figure 16;

Figure 18 is an enlarged view of a safety latch associated with the mobile base according to an aspect of the present invention;

Figure 19 is an enlarged view of a safety latch associated with the stationary base according to an aspect of the present invention;

Figure 20 is a top perspective view of the safety latch between the bridge and the stationary base according to an aspect of the present invention;

Figure 21 is a view from below of a locking catch of Figure 19 for securing the safety latch in place when the bridge is retracted according to a further aspect of the present invention;

Figure 22 is a view of one part of an alternative embodiment of a safety latch system according to a further aspect of the present invention;

Figure 23 is a perspective view of another part of the safety latch system of Figure 22;

Figure 24 is a perspective view of the safety latch system of Figures 22 and 23 in a release position and

Figure 25 is a perspective view of the stationary base, the bridge and the mobile base with the safety latch system of Figures 22 to 24 in position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 is an assembled view of the mobility aid of the present invention shown generally as 10. It includes a mobile base 12, an extendible bridge 14 and a stationary base 16. A rolling or sliding seat 17 is also shown. In this embodiment, the sliding seat 17 is of the tilting type.

The mobile base 12 may be of the commode type, which includes a built-in bed pan 18, supported from a seat frame 20. The seat frame 20 is in turn supported by height adjustable columns 22. Opposed caster support arms 24, 26 support individual caster wheels 28, 30, which can be locked by locking levers 32, 34. As these elements are conventional they are not described in any more detail herein. Similar elements may be present under the opposite side of the mobile base 12 but are not discussed in any detail as they will be apparent to those skilled in the art. A stiffening brace 36 may be used to secure the mobile base frame elements together as shown.

The stationary base 16 may include four support legs 40 which can also be made height adjustable, by means of telescoping sections in a known manner. The support legs 40 extend down from the stationary base seat frame 42 and may be secured thereto by welding, bolts, or other suitable attachment mechanisms. Extending laterally across the front two support legs and the back two support legs are stabilizer bars 44. The stabilizer bars 44 are secured to each of the respective legs and are extendible to permit the rubberized ends 46 to be pressed against the sides of the bathtub 48 for added stability. The lateral stabilizer 44 bars may not be essential, but are useful to provide additional stability if the circumstances warrant.

The sliding seat 17 includes a seat frame 50, which may have attached to it a back rest 52, a commode style cushion 54, arm rests 56 a head rest 68 and leg rests 70. Handles 72 may also be provided as shown. In use the sliding seat is translated along a translation axis between the stationary base and the mobile base. As described in more detail below, the embodiment shown in Figure 1 is for a tilting seat frame, which permits the seat 17 to be tilted so that the leg rests 70 can be lifted up and over the bathtub wall 74 during the movement or translation of the seat 17 from one base to the other.

The extendible bridge 14 may be permanently attached, and stored in the stationary base 16. The bridge 14 may include a locking clip 78 to lock the bridge 14 to the mobile base 12 in the extended position as shown in Figure 1. The extension and retraction of the bridge 14 together with the function of the bridge 14 in supporting the sliding seat 17 is described in more detail below.

Figure 2 is an isolated view of the mobile base 12 for ease of understanding. As can be seen the mobile base 12 has a frame 20 which may include main load bearing frame elements 82, 83, which can be bolted, welded or the like to the height adjustable support columns 22. Also shown are bedpan supports 84, 86, for holding a bedpan in position relative to the seat frame 20. Extending between the main load bearing frame elements are the cross-bracing track elements 88 and 90. Most preferable these track elements are provided with a track opening 92 facing inwardly and are spaced apart enough on the main load bearing frame 20 so that the sliding seat can fit between the track elements 88 and 90. The track elements 88 and 90 may also be welded or bolted on the main load bearing frame 20 and can have end caps or stops 94. As shown alignment features 96, 98 may be provided on the frame element 80, to help align and secure the extendible bridge 14 to the mobile base 12 as explained in more detail below. In this embodiment the alignment features are outwardly extending cones, but in another embodiment described below they may take the form of inwardly extending cones.

Figure 3 is an isolated view of the stationary base 16 with the extendible bridge 14 removed for ease of illustration. It will be understood that in use, the extendible bridge 14 is permanently affixed to the stationary base 16. The stationary base 16 is shown placed in a tub 100, having a faucet 102, a drain 103 and tub walls 74. This in tub position for the base 16 is by way of example only and it will be understood by those skilled in the art that the present invention may be applied in other contexts such as in shower stalls and the like. The stationary base 16 includes the four support legs 40 which can also be made height adjustable. As will be now appreciated to ensure that the bridge extends across to the seat frame in a level manner requires height adjustability of the mobile base 12, the stationary base 16 or preferably of both. The legs 40 extend down from the stationary base seat frame 42 and may be secured thereto by welding, bolts, or other suitable attachment mechanisms. Extending across between the two support legs on one side and the two support legs on the other side are stabilizer bars 44. The stabilizer bars 44 are secured to each of the respective legs and are extendible to permit the rubberized ends 46 to be secured against the inside faces of the bathtub 100 for additional lateral stability. While these lateral stabilizers 44 are preferred they may not be required in all circumstances. The legs 44 may be secured to track elements 104, 106 which in turn may be secured to cross supports 108, by bolts, welding or the like. The track elements 104, 106 have openings which face inwardly 105, 107 and which are explained in more detail below. The track elements 104, 106 may include a compound cross sectional shape to permit the track elements 104, 106 to support both the retractable and extendible bridge element 14 as well as the sliding seat 17.

Figure 4 is a view in isolation, for ease of illustration, of the extendible and retractable bridge element 14. As shown there are two bridge track elements 110 and 112 which have compound shapes in profile. On a bottom face, there is an opening 114, 116 respectively, into a keyway slot 1 18, 120 for fitting around a key (shown in Figure 6) formed in the stationary base 12. The key into keyway interaction allows the bridge element to slide between the extended and retracted positions along a predetermined translation axis. Lateral openings 124, 126 are also shown for receiving truck wheels which support the sliding seat as explained in more detail below. Also shown is a manual clip 130 and clip lever 132 for locking the extendible bridge onto the mobile seat base 12. Also shown are a catch 136 and a stop 138 for limiting the movement of the bridge in certain cases relative to the bases. Cross braces 139 are also shown, holding the track elements 110 and 112 in position.

Figure 5 shows the bridge 14 mounted to the stationary base 16. As can be seen the bridge can be extended or retracted along the directions of the double ended arrow 140. In this Figure 5 the extendible bridge 14 is partially extended out from the stationary base 16.

Figure 6 shows in more detail the nature of the interaction between the bridge 14 and the base 16. This is an end view of the back side of the bridge 16. As shown the stationary base may be provided with a t-shaped flange 141 which fits into the opening 114 and into keyway 118. A slider 142 is secured to both lateral keyways to reduce the sliding friction between the bridge 14 and the base 16. In this way the bridge 14 can be easily slid along the base 16 between extended and retracted positions. The present invention further comprehends that rollers may be used in the place of any sliders, but the sliders have provided reasonable results.

Figure 7 shows the front view of the bridge 14 and the keyways slots 118 and 120. A pair of front sliders 144 may be provided to again reduce the sliding friction arising from the movement of the bridge relative to the base 16. The front sliders 144 may be provided by cover plates 146 attached by means of screws, bolts or the like 148 to affix the cover plates 146 to the front sliders 144. The bridge may have low friction sliders at both the front and the back of the tracks to permit the easy movement of the bridge along the t-shaped flange 141 (shown in Figure 6).

Figure 8 shows one embodiment of a sliding seat frame 150 for a tilting seat. The seat frame 150 may include opposed support flanges 152, 154 which are curved to permit a seat, mounted to said frame, to be tilted. Curved slots 156, 158 on the support flanges act as guides for the tilting seat, which will be generally known to those skilled in the art and which is therefore not described in any more detail herein. Also shown on the tilting seat frame 150 are cross support arms 160, 162 to which may be mounted four trucks 164, 166, 168 and one which is hidden by the support flange 152. The trucks are explained in more detail below.

Figure 9 shows a cross section through one of the trucks, say 164, in use. Although the description applies to only one of the trucks it will be understood that the same design can be used in the other trucks as well. The trucks consist of an axle 170 which may be housed in the cross support arm 160 for example. Bolts 172, 174 may frame the axle 170. The bolts may be used for example to secure the seat frame 150 to the cross support arm 160 as shown in Figure 8. A screw 176 may be used to secure the axle 170 in place. The axle 170 may be a compound axle formed from an outside part 171 and an inside part 173 which connect together to permit the axle 170 to extend out from both sides of the truck as shown. Wheels 178, 180 are shown on the outer and inner ends of the axle 170.

Also shown are a cross section through part of the track frame shown as 200 of the stationary base 16, which is carrying part of the bridge shown as 202. The frame includes a channel shape (in this case a rectangular channel shape) 203 with a side opening 105 as described above. Preferably the side opening 105 is large enough to allow the axle 170 to pass there along, but small enough to prevent the outer wheel 178 from pulling out of the track rectangular channel 203. Curved upper and lower portions 204 and 206 may be used for this purpose. Inner wheel 180 is housed in a track 210, which is part of the extendible bridge and which includes the track opening 92 referred to above. In this case the base 212 of the track 210 may be positioned slightly lower that the base 214 of the track 203, so that the weight of the seat is primarily carried by the outer wheel of the truck 178 rather than the inner wheel 180. In this way the bridge 14 can be easily extended and retracted even when the seat has been slid fully onto the stationary base 16, because there is not much, if any, load on the bridge track being transmitted by the inner wheel 180. The weight distribution which prefers the outer wheel 178 and loading the stationary base 16 rather than the bridge 14 adds to the ease of sliding the bridge 14 already provided by the low friction sliders discussed above, the combination of which may make the present invention easy to use.

Figure 10 shows a non-tiling seat frame embodiment for the sliding seat portion 17 of the present invention. It includes cross supports 211 , 213, which may be welded, bolted or otherwise attached to frame elements 215 and 216. Again, four trucks may be located in the frame elements 215 and 216 at 220, 222, 224, and 226. The trucks include both inner and outer wheels 278 and 280 as discussed below. The frame elements 215 and 216 are aligned with the axis of translation of the sliding seat 16.

Figure 11 shows a cross section of one of the trucks of Figure 10 for illustration purposes. The elements of this drawing are very similar to those explained in respect of Figure 9 above. Although the description applies to only one of the trucks it will be understood that the same design can be used in the other trucks as well. The trucks consist of an axle 270 which may be housed in the cross-support arm 260 for example. A screw 276 may be used to secure the axle 270 in place. The axle 270 may be a compound axle formed from an inside part 272 and an outside part 274 which connect together to permit the axle 270 to extend out from both sides of the truck as shown. The wheels 278, 280 are shown on the outer and inner ends of the axle 270. It will be understood that the present invention comprehends that the rollers or wheels described above could be replaced with other low friction elements such as sliders, however, the wheels as described have provided reasonable results.

Also shown is a cross section through part of the stationary base 16 shown as 300, which is carrying part of the bridge shown as 302. The base 16 includes a channel shape (in this case a rectangular channel) 303 with a side opening 105 as described above. Preferably the side opening 105 is large enough to allow the axle 270 to pass therealong, but small enough to prevent the outer wheel 278 from pulling out of the track tubular 303. Curved upper and lower portions 304 and 306 may be used for this purpose. Inner wheel 308 is housed in a track 310, which is part of the extendible bridge 14 and which includes the track opening 92 referred to above. In this case the base 312 of the track 310 may be positioned slightly lower than the base 314 of the track 303, so that the weight of the seat is primarily carried by the outer wheel 278 of the truck rather than the inner wheel 280. In this way, the bridge 14 can be easily extendible and retractable even when the seat 17 has been slid fully onto the stationary base 16, because there is not much, if any load on the bridge 14 being transmitted by the inner wheel 280 to the bridge 14. The weight distribution which prefers the outer wheel 278 and loading the stationary base 16 rather than the bridge 14 adds to the ease of sliding the bridge 14 which is provided by the low friction sliders discussed above all of which may again make the present invention easy to use. It will be understood by those skilled in the art that rather than being in a side by side relationship the present invention comprehends that the discontinuous track could be made from track sections that were spaced above the other in height. In this case the same number of trucks would be required, but rather than being on opposite sides, the wheels would extend out of the same side and would be placed at a height suitable for engaging the height of the tracks. However, this is believed less preferred as it would interfere with the height of the seat because the discontinuous track sections would be stacked one above the other thereby potentially requiring a higher seat.

Figure 12 shows the elements of the invention in an assembled and in use position. The mobile base 12 is shown in a location adjacent to a bathtub in this example. Preferably the caster wheel of the mobile base 12 will be locked at this time. The stationary base 16 is shown in the bathtub 100 and the bridge has been extended out from the base 16 and latched to the mobility base 12 at 400. The sliding seat frame 17 is shown part of the way across the bridge 14. Referring to the two front trucks (assuming the seat is moving in a direction towards the stationary base 16) they can be seen as being supported by the inner wheels as the outer wheels are freely suspended in the air at 402. In contrast, at the rear trucks the outer wheels are supporting the seat frame 17 in the tracks whereas the inner wheels are suspended in the air 406 and 408. It will be noted that in the extended position the bridge still overlaps with the stationary frame by an amount shown as OL in the drawing. As can now be understood in this part of the travel of the sliding seat 17, both of the inner and outer wheels of the forward trucks will be engaged with respective inner and outer tracks. In this way, the present invention provides for a smooth transition between the load bearing of the inner and outer wheels of the front trucks (on different portions of the discontinuous track sections) and thus between the bridge 14 and the stationary base 16. As noted above the bridge can be sized and shaped to prevent the inner wheels from being load bearing when the sliding seat is located all the way onto the base 16 to make the bridge 14 more easily retractable or extendible even though it is under the sliding seat 17 while the user is on the seat 17. It will be understood that there will be a slight downward movement of the seat when the rollers leave the stationary base and a slight upward movement when the rollers engage the mobility base and vice versa.

Figure 13 shows an alterative embodiment in which the sliding seat 17 is of the non-tilting type. In this case the leg rests 410, 412 are attached to the mobile base 12, rather than to the seat 17. As well, leg rests 414 and 416 are attached to the stationary or bath base 16. So, in the case of a non-tilting seat the user simply moves from one set of leg rests to the other, depending upon which direction the sliding seat is moved. This requires that the legs of the user be physically lifted over any obstacles, such as the bathtub wall 74 or a low shower surround wall and the appropriate choice between tilting and non- tilting seat for the present invention will need to be determined on a case by case basis, depending upon cost, convenience and ability as the case may be.

A further aspect of the present invention can now be understood. In a preferred embodiment, the present invention provides for a safety lock system to prevent the seat from sliding when it is not safe to do so. Figure 14 shows the stationary base 16 with the bridge 14 extended. The bridge 14 includes bridge extension bar 500, which is secured by means of two screws 502, 504 at an end plate 506 at either end. The screws grip into a groove 508, and a similar structure is provided at the opposite end of the extension bar 500. By backing off the screws, the bar 500 can be moved relative to the rest of the bridge 14 and positioned at an appropriate distance along the groove 508. As explained below the position of the extension bar 500 determines how far the bridge may be extended. Since the position of the bar 500 can be varied the maximum extension length of the bridge can also be varied to suit the circumstances of the user. Part of the end plate 506 can be formed as a stop which extends down into the path of the stationary base support cross member shown in this Figure as 510. In this way adjusting the position of the extension bar 500 adjusts the amount the bridge 14 may be extended out from the base 16.

Figure 14 also shows a locking latch 514 which is explained below. Also shown are the bridge locking clasp 514 and the protruding conical guides 516 and 518. Matching conical recesses 520, 522 (shown in Figure 15) may be provided on the mobile base to help align the bridge with the mobile base when the two are being docked together. The inter-fitting conical shapes act as an alignment means for the bridge to mobile base docking connection.

Figure 15 shows the bridge docked to the mobile base with the locking clasp 514 pulled down to draw the loop 524 onto the fixed hook 526. This simultaneously draws the cones into the conical recesses. Also shown is a seat safety locking tab 528, which extends upwardly in the seat locking position. In a preferred embodiment, the locking tab 528 prevents the seat, on the mobile base, from sliding laterally off the mobile base unless the seat locking tab 528 is withdrawn. The only way to withdraw the locking tab or move it down is to fully engage the loop 524 on the fixed hook 526 as explained below.

In Figure 16, the docking guide on the mobile base has bee removed for clarity. The clasp 514, the loop 524 and the fixed hook 526 are shown. Associated with the fixed hook 526 is a trigger mechanism 530 which is positioned to be engaged by the loop 524 when the loop 524 is placed onto the hook 526 and tightened. The trigger mechanism is preferably sized and shaped so the act of drawing the loop 524 onto the hook 526 engages the trigger 530 causing it to pivot about axle 531 which in turn lowers the locking tab 528 thus removing the locking tab 528 as a barrier to the movement of the seat off the mobile base. In this preferred embodiment, the only way to lower the locking tab 528 is for there to be full engagement of the loop 524 within the hook 526 - in other words the seat is not moveable until and unless the bridge is properly engaged or docked with the mobile base.

Figure 17 shows a side view of the safety release trigger mechanism 530 of Figure 16. By drawing the loop 524 in the direction of arrow A, par to the trigger mechanism 530 is drawing in direction of arrow B. This rotates axle 531 causing the other part of the trigger mechanism 530 to rotate in the direction of arrow C. In turn, this is linked to safety locking tab 528, which is then drawn in direction of arrow D. The trigger mechanism 530 is sized and shaped to remove locking tab 528 from the path of the seat.

Figure 18 shows a further safety feature of the present invention. As shown there is a first pivoting safety locking lever 540, which may be located beneath the seat on the mobile base within easy reach of a caregiver or the like. The locking lever includes an actuator arm 542, a pivot 544 and a locking end 546. A bell-shaped locking plate 560 is attached to the seat frame. The bottom face of the locking plate 560 may include curved guides surfaces 562 and 564 and a locking slot 566. By manipulating the actuator arm 542, the locking end 546 can be engaged or disengaged from the locking slot 566. As can now be understood, even with the locking tab 528 in the lowered position because of the engagement of the trigger mechanism when the bridge is fully docked, the seat cannot be moved off the mobile base until the locking lever 540 is manipulated by the caregiver or the like to unlock the seat for movement along the bridge.

Once both locking mechanisms have been released, the seat may be slid across the docked bridge from the mobile base to the stationary or bath base. Figure 19 shows a second safety locking lever 640 which is similar in all material respects to the locking lever 540, but is mounted on the stationary or bathtub base. When the seat is in position on the stationary base, then a locking end 646 of the locking lever 640 will ride over a curved guide portion 662 and the locking end 646 will be captured in locking slot 666.

Now the bridge can be retracted. As shown in Figure 20, a safety bridge latch 511 is securing the bridge in the fully extended position. So, the first step is to release the latch 512 from the fixed hook 526 so that the far end of the bridge is disengaged. Then the next step is to push the handle 700 sideways which rotates a latch member 702 out of engagement with a locking bar 704 to allow the bridge to be retracted into the stationary or bath base.

A further safety feature is then presented in Figure 21. The locking lever 640 is in position holding the seat in place on the stationary base. As the bridge is retraced a spring-loaded catch 706 is biased to a position where one end 708 abuts the locking lever, preventing the locking lever from being moved to a seat unlocked position. The catch 706 can only be moved out of the way of the locking lever 640 by moving the bridge to the fully extended position where the bridge stop 710 interacts with the exposed end 712 of the catch 706. This rotates the catch 706 and permits the locking lever 640 freedom of rotation to allow the seat to be unlocked. Most preferably the pivot point 714 of the catch 706 is off set from the line of force generated by the locking lever 640 to ensure that the locking lever can't be forced open even when the bridge is not extended. In other words, the seat cannot be unlocked by the caregiver unless and until the bridge is back in the fully extended position.

It can now be appreciated that the present invention may provide several safety features to ensure that the bridge is in position before the seat can be moved. More specifically, two catches engage the seat when it is on the mobility base and the seat cannot be moved until both are released. In this embodiment one catch is released by docking the bridge securely with the mobile base and the second is released by a caregiver or the like. The bridge itself is extendible to any desired extend by adjustment of the extension bar 500 which carries a bridge stop which engages the frame to prevent any over extension of the bridge. When the bridge is fully extended, then the bridge is also locked into place by a secondary locking latch mounted on the stationary base. To retract the bridge requires both ends of the bridge to be released. The retraction of the bridge locks a seat safety latch in place which in turn locks the seat in place on the stationary base. The caregiver cannot unlock the seat for movement until the bridge is fully extended.

Figure 22 shows an alternative safety latching system according to the present invention. In addition to the components previously described, this embodiment includes a lift arm 600 which interacts with raiseable rail 602. When the loop 603 is drawn onto the catch 605, the lift arm 600 is drawn into engagement with the rail 602 at 607 to raise the rail 602 to a safety latch release position. Preferable the rail 602 is part of a four-bar assembly which allows the rail 602 to rise along its length rather than only at one end as will be apparent from the further description below.

Figure 23 shows the other end of the bridge when the bridge has been extended to the fully extended position. A second lift arm 604 is mounted to the adjustable end plate 611 for the bridge 14. As the second lift arm 604 encounters the cross member 613 of the stationary base, when the bridge 14 is in the fully extended position, lift arm 604 is caused to rotate which in turn causes the angle 606 to be raised which in turn causes the second raiseable rail 608 to rise. It will be understood that the first raiseable rail 602 is on one side of the bridge 14 and the second raiseable rail 608 is on the other side of the bridge 14. When both ends of the bridge 14 are secured, both rails 608 and 602 are raised.

Figure 24 shows a safety release position for the raised rails 602 and

608. A safety latch 610 is shown pivotally attached to the moveable seat 17 at 612. A lift tab 614 on the safety latch 610 interacts with one of the raiseable rails at 616. The lower bars of the rail are shown at 618. A locking tab is shown at 619. When the rail is raised and the safety latch 610 is raised by the lift tab 614 interacting with the raised rail 602, the locking tab 619 is in a position that is clear of any obstructions. In this position the moveable seat 17 can be moved from one base to the other.

Having described the individual components, the overall structure of this further embodiment can now be better understood. In Figure 25 the moveable seat 17 seat frame 20 is shown with safety latches 610, 620, 630 and 632 located at each of the four corners. They are sized, shaped and positioned to interact with the rails 602 and 608 as described above. The raiseable rails 602 and 608 are shown, on the bridge 14. With either of the rails in the lower position the locking tabs at either end of the lowered rail will prevent the sliding seat from being moved regardless of its starting position, namely whether it is located on the mobile base of the bath or stationary base. When the bridge is locked onto the moveable base, rail 608 is in the raised position. When the bridge is fully extended from the stationary or bath base then the rail 602 is in the raised position. With both rails raised all four safety latches 610,620, 630 and 632 are lifted into a disengaged or unlocked position, freeing the seat 17 up for movement along the bridge 14. Conversely if either or both ends of the bridge 14 are not secured to their respective bases, then the locking tabs 619 of the four safety latches 610, 620, 630 and 632 will prevent movement of the seat along the bridge. As can now be understood the further embodiment of the safety system provides a safety system that is active in all cases. Thus, if there is an unsafe condition at either end of the bridge, the seat 14 will not be moveable. The seat 14 is only moveable onto the bridge from either direction when all of the components have been properly secured together.

It can be further understood that the present invention is versatile and can be set up for any suitable gap between the stationary base and the mobility base as dictated by obstacles such as toilets of other bathroom fixtures or the like. Adjusting the bridge extension length is achieved by means of adjusting the position of bridge extension bar 500. Adjusting the bridge extension bar 500 does not affect any of the safety systems described above as they all work the same regardless of the extent of the maximum extension of the bridge once the position of the extension bar is set up to the desired maximum extension. In this way, the present invention can be used in a variety of circumstances without requiring specific and separate bridge extensions as may be required in the prior art. Further no matter how far or short the bridge extends, the safety systems of the present invention will be engaged in each case without any further adjustment being required.

It will now be understood that the present invention is described above with respect to certain preferred embodiments and that the scope of the invention is only limited by the broad ambit of the claims attached. Various alterations and modifications are comprehended by the claimed invention including the titling and non-tiling seat and other variations which will be apparent to those skilled in the art.