WO2019126867A1

WO2019126867A1 - Assistive mobility device

Info

Publication number: WO2019126867A1
Application number: PCT/CA2018/051588
Authority: WO
Inventors: Jean-Pierre Berger; Gordon THIESSEN; Lisa BOULTON; Ernie Janzen; Johanne Mattie
Original assignee: Ergosentri Concepts Inc.
Priority date: 2017-12-28
Filing date: 2018-12-12
Publication date: 2019-07-04

Abstract

The present invention is a stable assistive mobility device. A vertically tiltable seat is coupled to a suitably shaped wheeled frame that allows users to easily mount and dismount the device from the rear, to propel the device from a seated or near standing position, and to steer without the use of hands.

Description

TITLE OF THE INVENTION

ASSISTIVE MOBILITY DEVICE FIELD OF THE INVENTION

This invention relates to assistive mobility devices. More particularly this invention relates to wheeled assistive mobility devices having seats for supporting or partially supporting the weight of the user.

BACKGROUND OF THE INVENTION

In many prior art walkers or other mobility devices, the user is required to crouch while propelling himself or herself. However, a crouched position can lead to issues such as back pain, and can be problematic in cases of limited lung capacity. Moreover, a crouched position is associated with the social stigma of sickness or old age.

Many mobility devices are too bulky and cumbersome to be used effectively in an indoor environment and they do not allow free use of the hands for purposes other than reaching out for support, as they usually require the use of the user’s hands to direct the device or for support during use of the device.

Wheeled mobility devices comprise different types. The first type are walkers wherein the user walks behind the device. Elderly persons usually lean on the handles for better stability. Common walkers or rollers of this type (of. U.S. Patent No. 5,603,517 and U.S. Patent Publication No. 2016/01 13833) are cumbersome in an indoor environment and are unable to effectively approach tables, counters or appliances. In some cases, such as is exemplified by U.S. Patent No. 7,669,863, the transition from standing to sitting on the walker requires the user to twist or turn 180 degrees, causing a risk of loss of balance.

A second type of mobility device is wheelchairs wherein the user is completely seated, including self-propulsion chairs and those requiring assistance to move. A third type is represented by assistive devices that attach to the user’s torso, as exemplified by U.S. Patent Publication No. 2010/0170546 which assists the user in balance and body orientation but requires the user to bear his weight about the torso. An advantage of this type of device is that the user’s hands remain free and the design of the device allows fairly close approaches to vertical surfaces and counters to facilitate domestic activities.

The present invention relates to a fourth category of assistive mobility devices, namely wheeled devices wherein the user’s weight is supported by a seat but that still allow use of the user’s legs to move the user’s body along with the device.

U.S. Patent No. 8,151 ,812 discloses a walker with adjustable seat height and wherein the user can straddle the seat from behind without substantial obstruction. The device requires effort from core muscles to change direction without the use of the hands and is cumbersome at the front of the device, which impedes close approaches to vertical surfaces such as countertops.

U.S. Patent No. 4,621 ,804 discloses a walker equipped with an adjustable seat wherein the user can walk into the frame from behind the device but requiring assistance to harness the seat to the frame before using the device.

U.S. Patent No. 6, 161 ,860 discloses a scooter device that allows movement with the legs astride, but it requires the use of the hands to steer, and is entirely impractical for indoor use or to approach working surfaces.

US Patent No. 5,158,313 discloses a device that can support the user for moving around in a low seated position without necessarily using the hands for steering. A relatively large area is needed to turn the device and the design does not allow for lateral movement. The seat settings do not allow an adjustment while being seated or during the transition onto the apparatus. Moreover, the seat is far away from a countertop thus impeding the normal execution of the most common domestic activities.

U.S. Patent No. 9,623,926 discloses an outdoor recreational device that is approached from the rear by straddling a seat frame. Changes in direction are made by the user steering the device using a handle. The device is impractical in spatially constrained indoor environments and does not allow hands-free operation to perform tasks.

The present invention is designed to help people with reduced mobility and/or stability to be weight supported, to adjust the height of the seat between a sitting and a standing position, to easily transition onto and out of the device using an adaptive seat mechanism, to easily move around in an indoor environment such as a home, care facilities or other indoor places and to perform routine chores without the need to use the hands for support or direction while being close enough to the countertops. It helps to maintain autonomy, independence, retain dignity and minimize the need for assistance in the performance of daily tasks.

While use of the invention is not restricted to the indoor environment, it is suitable for use indoors. It is an object of the present invention to provide an improved assistive mobility device of the type that include a seat for supporting a user during movement. The improvements target improved mobility in spatially restricted environments, the ability to approach working surfaces such as countertops in close quarters, ease of mounting onto the seat and hands-free movement and changes of direction of the device.

These and other objects will be better understood by reference to this application as a whole. Not all of the objects are necessarily met by all embodiments of the invention described below or by the invention defined by each of the claims and any identified objects are objectives rather than promises.

SUMMARY OF THE INVENTION

The device according to the invention has a frame that allows space for movement of the user’s legs, provides a large enough footprint for device stability, enables easy mounting and dismounting of the device and enables hands free movement in close quarters to surfaces. In one aspect, the device has a frame that is adapted for stability as well as for approaching countertops and some furniture or appliances.

In another aspect, an adjustable seat swivels about the horizontal to facilitate easy mounting and dismounting and its height may be adjusted to allow easy transitions between a sitting position and a standing position.

In another aspect, directional changes for the device are facilitated by providing casters at both the front and rear of the device.

The invention comprises a frame having a shape and structure intended to give enough stability and mobility in narrow domestic environments and allows a close approach to the edge of the countertops for the execution of domestic activities such as washing dishes, ironing, cooking, or eating at a table.

The frame comprises a front frame and a support frame.

The front frame defines a substantially inverted U shape having a generally horizontal crossbar and two substantially vertical legs. The inverted U shape provides an unobstructed opening for the extension of the user’s legs and feet so as not to impede a natural stride motion and to allow the user to self-propel with ease and stability. Preferably the front frame width is at least 21” between the two front frame legs and 25” high from the bottom of the leg to the top of the crossbar.

The otherwise substantially vertical front frame legs curve outward at the bottom to casters mounted on the extremities of the legs. This feature allows access under some furniture bottom openings and under the overhang provided at the base of kitchen cabinets. In turn, that allows the device to get closer to the furniture or countertop than would otherwise be the case. The curve also allows the user to laterally displace the feet without impediment for lateral movement of the device.

The crossbar is located at a height close to a typical user’s pelvis height, when standing. That feature facilitates the control, propulsion and the steering of the device when using only the user’s core muscles and legs, rather than requiring effort from the upper body and limbs.

In order to give extra-support to the user the front frame accommodates two removable and adjustable rearwardly extending handles, preferably mountable near the intersection of the crossbar and the legs. The height of the handles is adjustable and they may be clamped to specific height and directions at the discretion of the user. The handles may be positioned in a forward, flat or backward position for the comfort of the user.

To easily accommodate different kinds and sizes of handles, especially those with tubes diameters found on most common off-shelf bicycle components, the top of the front frame legs comprise a tubular socket.

The support frame comprises a top section, a mid-section and a bottom section. The top section extends downwardly and rearwardly from the crossbar (of the front frame) to the mid-section. The forward end of the top section attaches to the crossbar at an angle of about 15° to the vertical to define a short straight portion before curving smoothly to reach the mid- section. This shape provides sufficient space to lower the seat, while keeping the user’s torso as close as possible to countertops, while also allowing the user to stand in front of the seat or be in a near-sitting position, and further leave space for the knees to move right and left without obstruction for example when propelling the device.

The mid-section is a substantially vertical portion of a tube to which the top section is joined. It includes an opening for receiving a vertically extending post or shaft on which a seat is mounted.

The bottom section is an extension from the mid-section that curves rearwardly from the mid-section and terminates in a caster assembly. The rearward curve is of low profile and relatively close to the ground, which enhances the ability of the bottom section to slide under openings (i.e. of a bed, sofa or seat). The rearward extension of the bottom section avoids interference with the user’s feet. The bottom portion extends along the centerline of the device, allowing the user to easily straddle the bottom portion for the purposes of mounting the seat or propelling the device with a natural walking type of stride, reducing contacts with the feet and ankles when the user is walking with the device.

A standard attachment allows for different types and sizes of wheels. The preferred embodiment has a hand-activated rear wheel locking mechanism while an alternative embodiment has a front wheel foot-activated locking feature.

The invention comprises a seat with adjustability in the vertical and horizontal directions as well as a rotational tilt mechanism. The adjustment options allow the user to find the most adapted posture for the performance of activities, to reduce pain or to increase stability.

Notably, the seat swivels from a vertical to a horizontal orientation to facilitate mounting and dismounting when intending to use or withdraw from the device. Most prior art devices require the user to turn the device or the user’s body around about 180 degrees in order to mount or enter the device, with the sitting position being in the opposite direction of the walking direction. The present invention allows the user to mount or dismount the device from the rear and walk forward in a single motion without having to turn around or turn the device around and while keeping the feet on the ground. The transition onto the device could be done either from a standing position straddling forward towards the seat and exercising slight groin pressure on the tilted seat or from a sitting position (for example from a chair) with the bottom of the support frame under the chair and transitioning from the sitting position, gently sliding against the vertically tilted seat and with a slight pressure of the groin to force the seat to slide into its locked horizontal position

The seat mechanism is adjustable as to the height of the shaft supporting the seat from the mid-section of the frame. A hydraulic or spring-loaded mechanism allows the user to adjust the height of the seat while in position on the seat for comfort in both the sitting and standing positions and optionally to lower the seat enough to maintain a normal standing position, using both legs and having both feet fully on the floor, thus dramatically easing the mount/dismount from the rear of the device. A tilt mechanism allows the user to walk in and on the seat without lifting one leg, while keeping the legs in a position closer to the natural hip axis and/or without reaching the seat by extending the legs and mounting on the feet tips. The seat tilt mechanism allows the seat to be tilted backward into a vertical orientation, lowering the back of the seat (usually the wider area of the seat) and therefore allowing an easier and smoother transition when mounting/dismounting. The user is able to walk straight into straddling the seat and urge it to return to a normal horizontal in-use orientation. During mount/dismount, the front casters are preferably locked to allow mounting or dismounting to be hands-free.

Preferably the seat may also be moveable horizontally rearwardly or forwardly along a rail that is provided in the preferred embodiment.

The maneuverability of the device is enhanced by providing omnidirectional casters on both the front legs and on the rear of the lower section rear of the frame. This allows one to steer the device without the use of hands, allowing the user to be hands-free to perform domestic tasks.

In one aspect the invention is a personal mobility device comprising a frame having a forward portion and a seat-supporting portion. The forward portion has an inverted U shape consisting of two legs and a portion connecting the two legs. The forward portion lies substantially in a first vertical plane. The seat-supporting portion extends rearwardly and downwardly from the connecting portion and terminates in at least one ground engaging roller. The seat-supporting portion lies substantially in a vertical plane that is orthogonal to the first vertical plane and extends from the connecting portion in a first straight segment extending downwardly and rearwardly and a second segment that curves away from the first vertical plane.

Each of the legs may terminate in portions that extend forward out of the first plane and that have rollers thereon (preferably casters). The seat-supporting portion terminates in a portion extending rearward and that has a roller thereon (preferably a caster).

The device may include a seat that is tiltable between a horizontal orientation and a vertical orientation. In yet another aspect, the invention is a seat assembly that is tiltable between a horizontal orientation and a vertical orientation. The assembly comprises a shaft, a support, a seat attachable to the support. The support is hingeably connected to the shaft for pivoting the support in relation to the shaft and a selectively releasable locking mechanism is provided for retaining the support in a horizontal orientation.

The seat assembly may further comprise a pin carried on the support. The pin is located on the support to align with an aperture when the support is in a horizontal orientation. A lever selectively withdraws the pin from the aperture. The foregoing may cover only some of the aspects of the invention. Other and sometimes more particular aspects of the invention will be appreciated by reference to the following description of at least one preferred mode for carrying out the invention in terms of one or more examples. The following mode(s) for carrying out the invention are not a definition of the invention itself, but are only example(s) that embody the inventive features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

At least one mode for carrying out the invention in terms of one or more examples will be described by reference to the drawings thereof in which: Fig. 1 is a front side view of the preferred embodiment of the invention with two rear casters;

Fig. 2 is a front side view of the preferred embodiment with a single rear caster;

Fig. 3a is a top rear side view of the preferred embodiment with the handles pointing forward;

Fig. 3b is a top rear side view of the preferred embodiment with the handles pointing inward;

Fig. 3c is a top rear side view of the preferred embodiment with the handles pointing rearward; Fig. 4a is a top view of the preferred embodiment of the device;

Fig. 4b is a side elevation of the preferred embodiment of the device;

Fig. 5 is a side elevation of the preferred embodiment of the device;

Fig. 5A is an enlarged view of area A in Fig. 5; Fig. 6 is a rear perspective view of the device of the preferred embodiment with the seat lowered in height and in a vertical, ready-to- mount orientation and a user approaching to mount the device;

Fig. 6 is a side elevation of the device showing a user in dotted outline mounting the device by straddling the support frame and moving across the seat, urging it toward a horizontal orientation;

Fig. 6a is a side elevation of the device and a user seated on the device, the user being shown in dotted outline;

Fig. 7 is a perspective view of the device according to a second embodiment, with the seat removed, and the device being folded using a hinge mechanism in the top section of the support frame;

Fig. 8 is an enlarged view of area B of Fig. 8;

Fig. 9 is a side elevation of the seat tilting mechanism in position for a vertical orientation of the seat, without the seat itself;

Fig. 10 is a side elevation of the seat tilting mechanism in position for a horizontal orientation of the seat, without the seat itself;

Fig.1 1 is a rear view of the seat tilting mechanism in position for a vertical orientation of the seat, without the seat itself;

Fig.1 1 a is a section view taken along line A-A of Fig. 1 1 showing the seat tilting mechanism in position for a vertical orientation of the seat, without the seat itself; Fig. 12 is a rear elevation of the seat tilting mechanism in position for a horizontal orientation of the seat, without the seat itself; and,

Fig. 13 is a front elevation of the seat tilting mechanism in position for a horizontal orientation of the seat, without the seat itself.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Fig. 1 and Fig. 2 are representations of the preferred embodiment of the personal mobility device according to the invention. A tubular frame 10 comprises a forward portion or front frame 1 1 and a seat-supporting portion or support frame 12 as shown in Figs. 4a and 4b.

The support frame 12 comprises a top section 50, a mid section 51 and a bottom section 52.

Omnidirectional casters 14 (front casters), 15 (rear casters) are provided at the base of the front legs 16 and at the base of the bottom section 52. A seat assembly 13 is coupled to the mid/rear frame 12 as described below. Seat assembly is described in more detail in below in relation to Figs. 9, 10 and 1 1.

Front frame 1 1 consists substantially of an inverted U shape formed by two vertical legs 16 and a crossbar 60 connecting the two legs. In the preferred embodiment, the two legs and the crossbar are combined into a single bent tube. The configuration of the legs and crossbar are such that the front frame lies substantially in a vertical plane defining the front of the device. The internal width of the front frame between the legs 16 is preferably 22” and the external width between the extremities of the front casters 14 is less than 30”. This allows most users to extend their feet forward between the legs 16 to propel the device forward or backward, and to provide sufficient space to move the feet laterally to change direction. The lower portions of the legs 16 curve forward as at 18 to facilitate lateral motion, increase the overall stability of the device and to allow the front casters 14 to extend under certain furniture to maximize the approach of the user to the upper portions of furniture such as countertops and tables. According to the preferred embodiment, the curve 18 begins about 4.5” from the ends of the legs. In the preferred embodiment, the bottom of each leg 16 is also wrapped in a cushioning material or bumper 20 to protect walls and furniture.

The top end 62 of top section 50 of the support frame 12 is coupled to the middle of the crossbar 60 by a connection 24 that allows the device to be disassembled for shipping and transportation. Two bolts/screws 25 secure the connection 24.

The top section 50 extends downward from the crossbar 60 at an angle of about 15 degrees to the vertical to define a short straight length before curving downward and backward 55 to the mid-section 51 , with a relatively small horizontal front to back extent (about 6.5” in the preferred embodiment). This shape allows the user to be close to countertops both in the seated and the standing position. It allows enough space for the user’s knees and legs to move laterally under the forward part of the top section while allowing the user to use the inner thighs to press on the top section 50 for lateral displacements. The approximately 15 degree angle from the crossbar 60 allows enough space for the seat be lowered vertically from a near standing position to a sitting position lower than the top end of the front frame 1 1 while still being positioned as close as possible to the front frame 1 1.

The top of mid-section 51 includes an opening, preferably of 1.5” in diameter, for receiving a vertically extending shaft 35 on which a seat assembly 13 is mounted.

The mid-section 51 is a substantially vertical portion of a tube to which the top section is joined and from which the bottom section 52 depends.

The bottom section 52 extends downward and rearward from the mid-section 51 and terminates in rear casters 15. That shape enhances the ability of the bottom portion 52 to slide under openings (i.e. of a bed, couch or seat) of about 7” or more. The rearward extension of the bottom section 52 minimizes interference with the user’s feet. The bottom section 52 extends along the centerline of the device, allowing the user to straddle the bottom portion for the purposes of mounting the seat or propelling the device with a natural stride. The rear section 52 of the support frame extends downward and backward from the mid-section 51 at an angle of preferably 1 13.5 degrees from the vertical section 51. In the embodiment of Fig. 2, a single rear caster 15 is provided on the bottom section rather than two casters.

The rear casters assembly comprises a flat metal plate 54 onto which the two casters 15 are secured. The top of the caster assembly includes a plastic cover 53 to hide and protect the locking mechanisms that may be actuated by hand brakes 22. In the preferred embodiment, the locking mechanism for the rear caster(s) 15 is operated with a handle 22 located on each lateral handle 40 that is securely fastened with a ring 42. In an alternative embodiment, the front casters 14 are equipped with a foot activated brake mechanism 17.

L shaped handles 40 are inserted into each side of the front frame. The height of these handles can be adjusted and secured in different heights or directions for the comfort of the user. In this embodiment, the fastening is achieved with a quick release ring 42 located on the side of the front frame. The handles can be securely tightened or removed entirely.

The handles may be positioned in a forward position 80 (Fig. 3a), sideways 81 (Fig. 3b) and in a rearward position (Fig. 3c). The user can remove completely the handles and use the device without them.

The structure and dimensions of the frame of the preferred embodiment allows passage through a width of 26” or more, to approach the edge of a countertop with a distance between the edge of the counter and the front of the seat of 3.5” or more and to pivot or swivel within diameter of 30”. The British Columbia Building Code in section 9.5.4.1 requires a nominal hallway width of 36” with a minimum width of 33.86”.

The seat assembly 13 comprises 4 different settings or adjustments. Fig. 6 shows the device in a ready-to-mount configuration, with the seat lowered (by lowering shaft 35) and the seat in the vertical orientation.

In order to mount the device, the seat is preferably lowered to a height approximately equal to the height of the user’s groin, and it placed in a vertical orientation so as to be tilted backwards. In order to mount the device, the user approaches the device from behind by walking forward and straddling the bottom section 52 that lies along the center line of the device. As illustrated in Fig. 6, the user’s groin 80 presses against the vertically oriented seat 82 to urge the seat to rotate forward. Fig. 6a shows the user having urged the seat to a fully horizontal orientation as the user assumes the seated position. The seat tilting mechanism locks the seat into position in the horizontal orientation.

Dismounting the device involves the user first unlocking the seat from its horizontal orientation and the user walks backward causing the seat to tilt backward by its own weight and allowing the user to clear the seat and the device.

Figs. 9, 10, 1 1 , 1 1 a and 12 show details of the seat assembly. The seat assembly and the transition of the seat from a horizontal (seated) orientation to a vertical orientation will now be described. Referring to Fig. 10, the seat assembly comprises an inverted U-shaped (best seen in Fig. 12) support 33 on which the seat is mounted (but the seat itself is not shown in Fig. 10). Support 33 is rotatable about pins 40a and 40b. A guide piece 39 is attached at the top of the vertical shaft 35 with two bolts 46a and 46b. Adjusting the tightness of the bolts 46a and 46b (best viewed in Fig.1 1 a) allows the vertical adjustment of the assembly in order to perfectly adjust the horizontality of the seat 82 when attached onto the top of the support 33

The pins 40a and 40b depend from two spaced sides 43a and 43b of the guide piece 39 and the support 33 rotates about pins 40a and 40b. With the seat assembly arranged for a horizontal orientation of the seat, spring loaded pull pins 31 a and 31 b are biased to engage into hole 32a and 32b to normally retain the assembly in that horizontal orientation. To disengage the assembly and enable it to pivot to the vertical orientation, facing levers 30a and 30b are mounted on each side of support 33 (best appreciated by reference to Fig. 1 1 ) by means of bolts 48a and 48b with a gap along the bolts 48a and 48b between the support 33 and the levers 30a and 30b. Pressing/squeezing levers 30a and 30b at their ends that are distal from the bolt 48a and 48b toward one another will cause the pins 31 a and 31 b located on each side of the levers at the ends proximal to the bolt 48a and 48b to pivot outward and to disengage from their respective holes 32a and 32b. Pressing both levers 30a and 30b disengages the pins 31a and 31 b from their holes 32a ad 32b, and allows the support piece 33 for the seat 82 to rotate rearwards about axle 40a and 40b and along the support guide 39 until it reaches rear stoppers 44a and 44b located on each side of the guide 39. The rear stoppers 44a and 44b can be positioned along the guide 39 to adjust the angle of the backward tilt position. When the support piece 33 slides forward to reach its horizontal position, the pins 31 a and 31 b slides along the guide 39 and re-engages their locked position in holes 32a and 32b. Front stoppers 42a and 42b located on each side prevent the support 33 from tilting further forward away from the guide 39. When tilted backward (vertically) as shown in Fig. 9, the user mounts the device by simply walking straight into the seat from the rear of the device and pressing the body (i.e. the groin) on the front of the seat 82, the seat tilts forward and locks itself in the horizontal position when the spring-loaded pins 31 a and 31 b re-engage into their respective opening 32a and 32b. This allows the user to position himself or herself on the seat while keeping both feet in contact with the ground.

The fixed guide piece 39 is securely attached to the shaft 35 that is inserted in the mid-section 51. A quick release fastener 26 allows the shaft to be securely positioned to the desired height. The height of the seat may be adjusted using a hydraulic mechanism. Release button 41 is depressed to allow the user to adjust the height of the seat by applying an appropriate weight on the seat. Preferably, the seat can be raised or lowered in a range of up to 5.9”.

The aft/front of the seat is positioned to be set as close to the front as possible while keeping enough space between the front frame and the body of the user. Two bolts 38a and 38b located at the top of the rotating piece 33 fasten a plate 37 to secure the rail structure 72 (Fig. 5) of the seat 82 when the seat is adjusted to its aft/front position. According to an embodiment, the normally unfolded and deployed device (Fig. 5) can be folded onto itself as seen in Fig. 7 so as to align the front frame with the support section in the same plane. A folding hinge 100 is located in the middle of the top section 50 of the support frame 12. Fig. 8 shows the hinge in the folded position while Fig.15a shows the hinge in a straight locked position. A bottom hinge 153 is inserted in the bottom section of the tube frame 156. A ring 158 rotates in order to lock the hinge in a straight position. A pushpin hole 154 locks the ring in a locked position. Top section tube 160 rotates around an axel/screw/bolt 152 located in the top portion of the hinge 153.

It will be appreciated that the forward curve of the front frame legs and the rearward extension of the bottom section of the support frame, in each case having a low to the ground profile, contribute to providing increased stability for the device, while also allowing the device to closely approach overhang surfaces such as counters and furniture.

The shape of the front and support frames allow unobstructed propulsion of the device by the legs of the user, even while the user is seated or partially seated. The shape of the support frame also allows the user to mount the device by straddling the bottom section of the support frame from the rear, without the need to lose contact with the ground and using a natural stride toward the seat.

The height adjustable and tiltable seat greatly facilitates mounting and dismounting the device by allowing a substantially walk-on walk-off feature.

In the foregoing description, exemplary modes for carrying out the invention in terms of examples have been described. However, the scope of the claims should not be limited by those examples, but should be given the broadest interpretation consistent with the description as a whole. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims

1 . A personal mobility device comprising:

a frame comprising a forward portion and a seat-supporting portion; said forward portion having an inverted U shape comprising two legs and a connecting portion connecting the two legs, said forward portion lying substantially in a first vertical plane;

said seat-supporting portion extending rearwardly and downwardly from said connecting portion and terminating in at least one ground engaging roller, said seat-supporting portion lying substantially in a vertical plane that is orthogonal to said first vertical plane; and wherein said seat supporting portion extends from said connecting portion in at least a first straight segment extending downwardly and rearwardly and a second segment that curves away from said first vertical plane.

2. The device of claim 1 wherein each of said legs terminates in a portion extending forward out of said first plane and having a roller thereon, and said seat-supporting portion terminates in a portion extending rearward and having a roller thereon.

The device of claim 1 further comprising a seat that is tiltable between a horizontal orientation and a vertical orientation.

4. The device of claim 1 wherein each of said legs terminates in a portion extending forward out of said first plane and having a roller thereon, and said seat-supporting portion terminates in a portion extending rearward and having a roller thereon; and further comprising a seat that is tiltable between a horizontal orientation and a vertical orientation.

5. A seat assembly that is tiltable between a horizontal orientation and a vertical orientation, said assembly comprising:

a shaft; a support;

a seat attachable to said support;

said support hingeably connected to said shaft for pivoting said support in relation to said shaft; and,

a selectively releasable locking mechanism for retaining said support in a horizontal orientation.

6. The seat assembly of claim 6 further comprising a pin carried on said support, said pin being located on said support to align with an aperture when said support is in said horizontal orientation, and a lever for selectively withdrawing said pin from said aperture.