CA2087508C - Personal mobility vehicle - Google Patents

Abstract

A personal mobility vehicle (10 or 80) having a very low center of gravity and compact overall size which facilitates travel in narrow hallways and in negotiating sharp turns as into a doorway along a narrow hall. The vehicle (10 or 80) includes a generally horizontally disposed preferably circular, disc-shaped frame (12 or 82) supported in close proximity above the ground by a steerable, motor-driven front or rear wheel (14 or 84) and two spaced rear or front wheels (20/22 or 100/102). A battery arrangement is connected to and supported by the frame (12 or 82) and operably connected between a control lever (44 or 162) in electrical communication with an electronic circuit (Figure 17 or 80) and the motors for propelling and steering the rear wheel 84. A seat (16 or 85) is provided whereby a user's feet may be comfortably supported on the frame (12 or 82). A circular cushioning ring (36 or 92), either fixed or preferably rotatably mounted and extending radially from the perimeter of the frame (12 or 82), contacts fixed objects such as walls, doorways and the like to facilitate tight maneuvers not heretofore possible with other such vehicles. Outrigger type anti-scuff and anti-tip wheels (118 and 122) may also be provided with vehicle 80.

Description

PERSONAL MOBILITY VEHICLE
This invention relates generally to self-propelled personal mobility vehicles for the handicapped and physically impaired, and more particularly to a compact, low center-of-gravity personal mobility vehicle which is uniquely adapted to negotiate within tightly confined spaces.
Presently, a broad array of self-propelled personal mobility vehicles for use by the handicapped and physically impaired are either patented and/or marketed. These vehicles are almost exclusively motorized and battery powered and consist of either three or four ground engaging wheels. However, the three wheeled tricycle-type version appears most popular. The drive arrangement may include a propulsion motor operably connected to either one or both of the rear drive wheels or incorporated into a front steerable wheel.
Typically, these available personal mobility vehicles are relatively massive in structure, some of which are also designed for outdoor operation in grass and dirt. Additionally, the center of gravity of the user seated atop such available vehicles is relatively high, producing a somewhat compromised stability.
In the typical front wheel steering vehicle, a steering tiller is incorporated to be manually operated by the rider. As a result, these vehicles are relativelylong to accommodate the steering tiller and must be entered from the side to get behind the tiller. Such vehicles also prohibit driving up to and under a table due to the presence of the steering tiller in the front of the vehicle.
A further limitation of personal mobility vehicles presently known to applicant resides in the limited ability of these larger vehicles to negotiate narrow hallways, to avoid running over the toes of others nearby on foot, and to be able to maneuver in dimensionally tight environments such as through a doorway of a narrow hallway. For example, those individuals who live in mobile homes or the like having narrow hallways, typically approximately 24" in width, are unable to utilize any such product currently on the market for this environment.
The present invention provides an extremely maneuverable, low center of gravity personal mobility vehicle which, in the preferred embodiment, will easily maneuver down narrow hallways, through narrow doorways at 90 degrees to such hallway, and into other dimensionally tight situations. A unique electronically controlled rear steerable propelling wheel arrangement is also provided, thus eliminating the front tiller. This invention also reduces the 20~75~8 likelihood of running over the foot of an able bodied pedestrian who may inadvertently get too close to the vehicle while underway.
This invention is directed to a personal mobility vehicle having a very low center of gravity and compact overall size which facilitates travel in narrow hallways and in negotiating sharp turns as into a doorway along a narrow hall.
The vehicle includes a generally horizontally disposed preferably circular, disc-shaped frame supported in close proximity above the ground by a steerable, motor-driven front or rear wheel and two spaced rear or front wheels, respective-ly. A battery arrangement is connected to and supported by the frame and operably connected between a control lever which activates an electronic circuitand the motors for propelling and steering the rear wheel. A seat is provided whereby a user's feet may be comfortably supported on the frame. A circular cushioning ring, either fixed or preferably rotatably mounted and extending radially from the perimeter of the frame, contacts fixed objects such as walls, doorways and the like to facilitate tight maneuvers not heretofore possible withother such vehicles. Outrigger type anti-scuff and anti-tip wheels connected to the frame may also be provided.
According to one aspect of the invention there is provided a self-propelled personal mobility vehicle which is extremely compact in size and maneuverable in tight quarters.
According to a further aspect of the invention there is provided a personal mobility vehicle which provides easy frontal access to the seat area and also has a very low center of gravity.
According to a still further aspect of the invention there is provided a personal mobility vehicle which will travel down narrow hallways such as are found in mobile homes and having a unique circular bumper or cushioned ring rotatable with respect to a circular frame so as to facilitate right angle turnsthrough doorways from such narrow hallways.
According to yet another aspect of the invention there is provided a personal mobility vehicle which reduces the likelihood of running over a pedestrian's foot.
According to yet another aspect of the invention there is provided a personal mobility vehicle having a unique rear steerable propelling wheel which greatly enhances maneuverability and compactness.
Embodiments of the invention will be described, by way of example, with reference to the accompanying drawings.

Figure 1 is a perspective view of one embodiment of the invention 10.
Figure 2 is a front elevation view of Figure 1.
Figure 3 is a perspective view of the invention 10 shown in Figure 1 in use.
Figure 4 is a perspective view of the invention 10 shown in Figure 1 positioned to travel around a corner of a wall.
Figure 5 is a bottom plan view of the circular frame of Figure 1.
Figure 6 is a bottom plan view of the frame shown in Figure 5 after removal of its bottom plate.
Figure 7 is a perspective view of the frame shown in Figure 5 after removal of the upper plate.
Figure 8 is a section view in the direction of arrows 8-8 in Figure 4.
Figure 9 is a left side perspective view of the preferred embodiment of the invention 80.
Figure 10 is a front perspective view of Figure 9.
Figure 11 is a top perspective view of the invention 80 shown in Figure 9 with the seat removed for clarity.
Figure 12 is an enlarged left side perspective view of the rear steerable, motor driven wheel of the invention shown in Figure 9.
Figure 13 is an enlarged right side perspective view of the right hand armrest and hand actuated control lever in Figure 9.
Figure 14 is a left side perspective schematic view similar to Figure 12 except depicting an alternate positioning arrangement for the drive motors.
Figure 15 is a perspective view of the Joystick-type single lever control of the invention 80.
Figure 16 is a simplified top plan schematic view of the invention 80 incorporating the alternate arrangement shown in Figure 14.
Figure 17 is a schematic diagram of the electronic control circuit for controlling the steering of the invention 80.
Referring now to the drawings and particularly to Figures 1 to 8, one embodiment of the invention is shown generally at numeral 10 and includes a frame assembly 12 and a motor driven front wheel assembly 14 which renders front wheel 18 steerable about axis A with respect to frame 12. The rear support arm 32 of front wheel assembly 14 is connected to frame 12 by plate 34. The invention 10 also includes a seat 16 rigidly mounted and upwardly extending from the disc-shaped circular frame 12.

-- 208~508 Frame 12 includes two spaced apart rear wheels 20 and 22 positioned astride the pedestal of seat 16 and supporting a battery 24 and control circuitry 26 which are operably connected between motor 28 and hand ~ctu~tor 44 on handle 42. By this arrangement, a user steerably controlling the device 10 by handle 42 on steering shaft 46 may controllably energize motor 28 through control 44 to propel the vehicle 10.
Frame 12 is cooperatively structured with seat 16 so that, as best seen in Figure 3, a user's feet may comfortably rest atop frame 12 without the need for additional foot support structure. Frame 12 is constructed, as best seen in Figures 5 to 8, of two spaced apart circular or disc-shaped plates 38 and 40, both of which include wheel clearance apertures 68/70 and 50/52, respectively.
Rear wheels 20 and 22 are rigidly mounted about axles 72 so as to downwardly extend below lower plate 40 for ground engagement.
Upper and lower plates 38 and 40, respectively are held spaced apart by a plurality of spacers 58 and threaded fasteners 74 therethrough strategically arranged for adequate support over the entire surface of frame 12. This arrangement affords convenient support of battery 24 through aperture 54 so as to rest atop lower plate 40. Also sandwiched between plates 38 and 40 are a plurality of rollers 56 which are mounted concentrically spaced about the common centers of plates 38 and 40 slightly inboard of the perimeters thereof.
These rollers 56, as best seen in Figure 8, are rotatably mounted about two partaligned shafts 62 which are held within aligned holes within upper and lower plates 38 and 40 by shaft extensions 66. Flanges 64 properly space each roller 56 sufficiently from upper and lower plates 38 and 40 provide free roller action.
Lockably engaged to surround the circular perimeter defined by the pluralit,v of rollers 56 is a rubber cushioned ring 36 having a metal inner rim 60 which rotatably engages within the roller 56. By this arrangement, the cushioned ring 36 is free to rotate back and forth in the direction of arrow B
about upper and lower discs 38 and 40.
As may now be better understood specifically referring to Figure 4, the functioning and usefulness of rotatable cushioned ring 36 is there depicted. Thedevice 10 is depicted encountering a corner C along a wall or hallway. To negotiate a sharp 90 degree turn, the handle 42 is turned as shown so as to aim front wheel 18 in the direction of the turn. As front wheel 18 pulls the device 10 around corner C, the cushioned ring 36, contacting against corner C, rotates in the direction of arrow B with respect to frame 12. In essence, then, - 2087~08 cushioned ring 36 remains somewhat stationary at its contact point with corner C, while the remainder of frame 12 and device 10 are propelled around corner C.
In experimentation, applicant has been able to manipulate the device 10 around virtually any 90 degree corner, including passage into doorways along narrow hallways which are only slightly wider than the overall diameter of the frame 12 or vehicle 10. Note that a fixed ring-shaped cushion in lieu of the rotatable cushioned ring 36 will also serve a somewhat similar function.
However, if the cushioned ring 36 is non-rotatable, some rubbing and movement between the corner C and the cushioned ring 36 must occur. Additionally, having the cushioned ring 36 rotatable, should the vehicle 10 being driven down a narrow hallway, inadvertently wanders off center so as to encounter one wall or the other, rotation of cushion ring 36 occurs to prevent any damage or scuffing of the wall surface.
Because rear wheels 20 and 22 are inboard of ring 36, and because frame 12 is in close proximity to the ground, the risk of running over a pedestrian's foot as in a crowded hall of a nursing home or shopping mall is significantly reduced.
It is noted that the frame may also be structured of braces or the like rather than plate material, which braces include support elements for each roller as previously described. Likewise, foot supports may be included astride the front wheel.
Referring now to Figures 9 to 17, the preferred form of the invention is shown generally at numeral 80 and includes a frame assembly 82 and a motor driven steerable rear wheel assembly 84 which renders this rear wheel assembly 84 steerable about an upright axis C with respect to frame 82. The invention 80 also includes a seat assembly 86 rigidly mounted and upwardly extending from the disc-shaped circular frame assembly 82 as will be described herebelow.
Frame 82 includes two symmetrically spaced apart front wheels 98 posi-tioned forwardly of and somewhat astride the pedestal 180 of seat 86 and supporting a storage battery 174. Frame 82 is cooperatively structured with seat 86 so that a user's feet may comfortably rest atop frame 82 without the need for additional foot support structure. Frame 82 is constructed of a circular or disc-shaped upper plate 88 and spaced apart lower plate (not seen) similar in structure to that shown in Figures 6 to 8. Upper plate 88 includes wheel 20875 ~8 clearance apertures 100 and 102 which are aligned with similar apertures in the lower plate. Front wheels 98 are rigidly mounted to frame 82 about axles 178 as best seen in Figure 11.
Upper and lower plates 88 and 90, respectively are held spaced apart by a plurality of spacers 58 and threaded fasteners (as previously described in Figures 6 to 8) therethrough strategically arranged for adequate support over the entire surface of frame 82. This arrangement affords convenient support of battery 174 through an aperture so as to rest atop lower plate 90. Also sandwiched between plates 88 and 90 are a plurality of rollers 56 which are mounted concentrically and evenly spaced about the common centers of plates 88 and 90 and slightly inboard of the perimeters thereof also previously described in Figures 6 and 8. These rollers 56, as best seen in Figure 8, are rotatably mounted about two part aligned shafts 62 which are held within aligned holes within upper and lower plates 88 and 90 by shaft extensions 46.
Flanges 64 properly space each roller 56 sufficiently from upper and lower plates 88 and 90 provide free roller action.
Lockably engaged to surround the circular perimeter defined by the plurality of rollers 56 is a rubber cushioned ring 92 having a metal inner rim which rotatably engages within the rollers 56. By this arrangement, the cushioned ring 92 is free to rotate back and forth in the direction of arrow B
around upper and lower discs 98 and 90 as previously described in Figures 6 to 8.
Referring particularly to Figures 9 to 12, the detail of the steerable rear wheel assembly 84 is there shown. A downwardly extending yoke 124 rotatably supports rear wheel 152, the yoke being supported for rotation only about axis C within a horizontal support 128. The horizontal support 128 is, in turn, rigidly connected to frame 82 by upright support 184 and plate 182 as shown.
The rear wheel propulsion arrangement includes a motor 140 mounted on plate 141 connected to yoke 124. The output shaft 148 of motor 140 is connected by drive belt 142 to pulley 144. This pulley 144 is also mounted for rotation within plate 141 and having a chain drive gear coaxially disposed on the opposite side of plate 141 which transfers power to chain 150 which is in drivable engagement with sprocket 146 coaxially connected to wheel 152. By this arrangement, actuation of motor 140 in either direction results in the corresponding movement forward or rearwardly of the vehicle.
Still referring to Figures 9 to 12, steerable control of the rear wheel 2087~08 assembly 84 includes a small geared motor (not shown except in Figure 14) mounted beneath plate 154 and in driving relation with output shaft 134 and pulley 136. Pulley 136 drivably engages with drive belt 132 so as to rotate sprocket 130 back and forth in the direction of arrow D in Figure 12. Sprocket 130, in turn, is connected to steering shaft 126 and yoke 124 as previously described. By this arrangement, controlled back and forth rotation of the motor (not shown) causes rear wheel 152 to move correspondingly back and forth to steer the vehicle 80.
Referring additionally to Figure 14, an alternate arrangement of the rear steering arrangement is there shown at 84a wherein rear wheel 152 is mounted within yoke 124 as previously described. In this arrangement 84a, the propulsion motor 140 is immediately laterally adjacent and in line with wheel 152 so as to have deleted the chain drive mechanism previously described. Steering motor 186 is operably connected to output shaft 134 on support 128a and is in driving engagement by drive belt 132 with sprocket 130 and steering shaft 134 as previously described.
Referring again to Figures 9 to 12, a pair of anti-scuff rollers 118 are connected on either side of frame 82 about symmetric upright axes by plates 120. These anti-scuff rollers 118, as best seen in Figure 11, prevent the rear steering assembly 84 from contacting a wall surface W (shown in phantom) when the perimeter of either side of frame 82 and one of the anti-scuff wheels 118 are in contact with the wall surface W.
To help prevent excessive tipping of the device 80 during sharp, rapid maneuvers, anti-tip wheels 122 are mounted about horizontal axes beneath each anti-scuff wheel 118 as best seen in Figure 9. These anti-tip wheels 122 are preferably caster-type wheels, although they may be mounted about fixed axes for rotation only as well. The anti-tip wheels 122 are positioned slightly abovethe support surface atop which the vehicle is resting in its static position. This clearance between the support surface and anti-tip wheels 122 is provided so that these wheels 122 only come in contact with the support surface when the vehicle 80 begins to lean laterally in one direction or the other. Otherwise, during normal operation, these anti-tip wheels 122 are not in contact with the support surface and do not interfere with maneuver-ability of the vehicle 80.
Referring now particularly to Figures 13 to 16, the means for controlling the steering and maneuverabilit,v of the vehicle 80 is there shown. A control lever 162 in the form of a "joystick" is pivotally mounted about its lower end for - 20~7~8 pivotal movement at its upper end in all directions within control box 160. Thiscontrol box 160 is connected in front of one arm rest 158 of seat 96 so that thejoystick 162 may be easily accessible to a user seated in the device 80.
The control box 160 includes a right/left potentiometer 164 and a forward/reverse potentiometer 166 connected orthogonally as best seen in Figure 15. Activation of the joystick 162 separately regulates each of these potentiometers 164 and 166 as will be described below, although both may be activated by diagonal movement of the joystick 162. A separate housing 172 supports an on/off switch 170 and a speed adjustment 168 for limiting the maximum speed adjustment attainable by the vehicle 80.
Propulsion of the vehicle 80 is controlled by the forward/reverse movement of joystick 162 which actuates potentiometer 166 and, in turn, regulates the level and polarity of voltage supplied to drive motor 140 from storage battery 174 through electrical conduit 176.
Referring to Figure 17, the electronic circuit for controlling the steering or rotational position of rear wheel 152 within yoke 124 is there shown. Actuation of the joystick 162 laterally to the right or to the left as shown in Figure 15 regulates steering potentiometer 164 outlined in phantom in Figure 17. The positioning of yoke 124 actuates a steering feedback potentiometer 138 which is also outlined in phantom in Figure 17. Feedback potentiometer 138 is held stationary as by conduit 156 as best seen in Figure 12. These two potentiometers 164 and 164, having variable resistors R1 and R2 contained therewithin, are employed to provide a command input signal and a steering feedback signal, respectively. The joystick 162 ~ctll~tes potentiometer 164 to provide a command signal. The positioning of yoke 124 actuates potentiometer 138 to provide feedback signal. If the two signals are in agreement on position,then a null or zero voltage condition will exist at summing junction 190, and nocorrective action will be called for of steering motor 186.
However, when the steering potentiometer 166 is shifted to a position to the right by the actuation of joystick 162, the null condition at 190 is disrupted and appropriate rotational action will be called for by steering motor 186. Thisis accomplished by the combination of resistors R5, R6, R7, R8, and R9 which form a decision making network to generate a desired corrective signal, known in prior art as a "bang" or "window" servo. This window servo will command the steering motor 186 to turn to the right. When the feedback potentiometer 138 senses sufficient corrective turning of yoke 124, a null condition will again occur at junction 190 and the window servo will cease activation of the steering motor186. When the command potentiometer 164 is activated to the left by joystick 162, a non-null condition occurs at junction 190 and the window servo will output a reverse polarity voltage which will cause the steering motor 186 to rotate in the opposite direction until another null condition has established atjunction 190.
Transistors Q1, Q2, Q3, and Q4 are drivers which allow voltage reversal and dynamic breaking of the steering motor 186. To accomplish this dynamic breaking, the transistors Q1 and Q2 are turned on by a high signal from amplifiers U1-1 and U1-2. To turn right, transistors Q3 and Q4 are turned on via a low signal from amplifiers U1-4 and a high signal from amplifier U1-2. To turn left, transistors Q1 and Q2 are turned on by a high signal from amplifier U1-1 and a low signal from amplifier U1-3. This circuit consisting of the four amplifiers within 188 in phantom is known in prior art as an "H" bridge.
While the instant invention has been shown and described herein in what are conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein, but is to be afforded the full scope of the claims so as to embrace any and all equivalent apparatus and articles.

Claims (9)

1. A self-propelled personal mobility vehicle for transporting a person comprising:
a generally flat frame supported generally horizontally above the ground by a rear wheel steerable about a generally upright axis and two spaced front wheels;
said rear wheel positioned along a central longitudinal axis of and rearwardly of said frame;
first drive means operably connected to said rear wheel for propelling said vehicle;
second drive means operably connected between said frame and said rear wheel for controlledly rotationally positioning said rear wheel about said upright axis;
a seat connected to and upwardly extending from said frame;
control means including a hand-actuated lever supported on said seat for selectively controlling the rotational speed of said first drive means and the rotational steering positioning of said rear wheel by selective activation of said second drive means;
a stored source of electronic power mounted on said frame and operably connected between said control means and said first and second drive means;
a cushioning ring connected around and radially extending from the perimeter of said frame;
means connected to said frame for supporting and permitting said ring to freely rotate about a common central upright axis of said frame and said ring;
said front wheels being spaced apart along a common transverse axis and positioned within the perimeter of said frame.

2. A self-propelled personal mobility vehicle as set forth in Claim 1, further comprising:
a cushioned anti-scuff wheel connected on each side of said frame and held for rotation about an upright axis;
each said anti-scuff wheel positioned radially outwardly from the perimeter of said frame and rearwardly of the widest transverse dimension of said frame whereby said rear wheel will not contact a straight wall surface when said frame and one said anti-scuff wheel are simultaneously in contact with the wall surface.

3. A self-propelled personal mobility vehicle as set forth in Claim 2, further comprising:
an anti-tip wheel connected beneath each said anti-scuff wheel, each said anti-tip wheel positioned vertically just above a support surface of said vehicle whereby one said anti-tip wheel will contact the support surface when said frame is tilted laterally from an at-rest generally horizontal position above the support surface.

4. A self-propelled ground-supported personal mobility vehicle for transporting a physically impaired user comprising:
a circular frame including two rigidly connected spaced apart discs, said frame supported generally horizontally in close proximity above the ground by a motor-driven steerable rear wheel and two spaced apart front wheels;
said rear wheel positioned centrally along a longitudinal axis of said frame and operably connected to, and in close proximity rearwardly of, said frame about an upright steering axis;
a seat connected to and upwardly extending from said frame, said seat positioned fore-and-aft with respect to said frame whereby a user's feet may rest atop said frame;
a cushioning ring roller mounted between said discs for rotation about a central upright axis orthogonal to said frame;
said ring radially outwardly extending from the perimeter of said discs;
control means including a hand-actuated lever supported on said seat for selectively controlling the rotational speed of said first drive means and the rotational steering positioning of said rear wheel by selective activation of said second drive means;
a storage battery supported on said frame and operably connected between said control means and said first and second drive means;
said front wheels spaced apart along a common transverse axis and positioned within the perimeter of said frame.

5. A self-propelled personal mobility vehicle as set forth in Claim 4, further comprising:
a cushioned anti-scuff wheel connected on each side of said frame and held for rotation about an upright axis;
each said anti-scuff wheel positioned radially outwardly from the perimeter of said frame and rearwardly of the widest transverse dimension of said frame whereby said rear wheel will not contact a straight wall surface when said frame and one said anti-scuff wheel are simultaneously in contact with the wall surface.

6. A self-propelled personal mobility vehicle as set forth in Claim 5, further comprising:
an anti-tip wheel connected beneath each said anti-scuff wheel, each said anti-tip wheel positioned vertically just above a support surface of said vehicle whereby one said anti-tip wheel will contact the support surface when said frame is tilted laterally from an at-rest generally horizontal position above the support surface.

7. A self-supported personal mobility vehicle for transporting a person comprising:
frame means supported above the ground by a steerable motor driven rear wheel positioned behind said frame means and two spaced apart front wheels for supporting the person in a seat connected to and upwardly extending from said frame means;
first drive means operably connected to said rear wheel for propelling said vehicle;
said drive means operably connected between said frame and said rear wheel for controlledly rotationally positioning said rear wheel about said upright axis;
cushioning ring means mounted on said frame means for free rotation and extending radially in all horizontal directions from the perimeter of said frame means for contacting fixed objects such as walls and doorways so as to guide said vehicle along a hallway or through a doorway;

control means including a hand-actuated lever supported on said seat for selectively controlling the rotational speed of said first drive means and the rotational steering positioning of said rear wheel by selective activation of said second drive means;
battery means operably connected between said control means and said first and second drive means;
said front wheels being spaced apart along a common transverse axis and positioned within the perimeter of said frame.

8. A personal mobility vehicle as set forth in Claim 7, further comprising:
a cushioned anti-scuff wheel connected on each said of said frame and held for rotation about an upright axis;
each said anti-scuff wheel positioned radially outwardly from the perimeter of said frame and rearwardly of the widest transverse dimension of said frame whereby said rear wheel will not contact a straight wall surface when said frame and one said anti-scuff wheel are simultaneously in contact with the wall surface.

9. A personal mobility vehicle as set forth in Claim 8, further comprising:
an anti-tip wheel connected beneath each said anti-scuff wheel, each said anti-tip wheel positioned vertically just above a support surface of said vehicle whereby one said anti-tip wheel will contact the support surface when said frame is tilted laterally from an at-rest generally horizontal position above the support surface.