Optically responsive mobility apparatus

A conventionally constructed baby walker 5 having a lower support member 6 to which are attached front wheels 10 and rear wheels 12 in contact with floor surface 14 has further optically activated brake assemblies 21a and 21b both moveably attached to support member 6, the bottom surface of each is rollably in contact with floor surface 14. Brake assemblies 21a and 21b each contain an infrared emitter and photodiode disposed above surface 14 and connected to a control circuit. An optically encoded arc shaped strip 15 having a pattern of alternating reflective and non reflective bands is further attached to floor surface 14 using conventional screws 19. Preferably strip 15 is placed in front of a descending staircase 20 or other level drop such as may be encountered with a patio or porch. As walker 5 is propelled across surface 14 and over strip 15, the optically encoded pattern is detected by the infrared emitter--photodiode combination of braking assembly 21a. In response to detecting this pattern, the control circuit releases a latching mechanism which engages braking assembly 21a. With brake assembly 21a engaged, the frictional contact between surface 14 and the bottom surface of brake assembly 21a is forceably increased. Additionally, engaged brake assembly 21a transmits a signal to brake assembly 21b which, in response to this signal, also engages thus further increasing the frictional contact between surface 14 and the bottom surface of brake assembly 21b. Both engaged brake assemblies now quickly arrest walker 5 and prevent any substantial movement past strip 15. Audible alarms contained within both brake assemblies 21a and 21b are additionally energized alerting attending personnel.

FIELD OF INVENTION 
This invention relates generally to mobility apparatus traversing a 
surface, and more particularly, to upright walkers, baby walkers, wheeled 
toys and wheelchairs having an optically responsive braking assembly. 
CROSS-REFERENCE TO RELATED APPLICATIONS 
This application is related to application Ser. No. 08/312,883 filed Sep. 
27, 1994 abandoned, which is hereby incorporated into this application. 
BACKGROUND OF THE INVENTION 
All mobility apparatus have the potential of being unintentionally 
propelled down an unprotected flight of steps usually resulting in serious 
injury to the user. This is especially true of curious infants placed 
within a conventionally constructed baby walker who are not capable of 
discerning the potential danger of an unprotected staircase. Additionally, 
many mobile toys have the same potential of being unintentionally 
propelled down an open staircase. Further, adults using wheelchairs or 
upright walkers face similar risks of receiving serious injury by 
unintentionally falling down either an unprotected staircase or between 
floor levels. 
In my aforesaid prior, co-pending application there is described an 
improved mobility apparatus which comprises a magnetically activated brake 
assembly which is responsive to a magnetically permeable boundary strip 
secured to the floor surface and preferably located in front of an open 
staircase. A number of these brake assemblies can then attached around the 
periphery of the mobility apparatus providing an effective braking system 
irrespective of any relative rotational movement of the mobility apparatus 
with respect to the boundary. As the mobility apparatus rolls over the 
strip the first brake assembly to pass over the strip automatically 
engages. Depending upon the number of brake assemblies placed around the 
periphery of the mobility apparatus and the combined weight and speed of 
the mobility apparatus and the occupant, the forward momentum of the 
occupied mobility apparatus may cause the mobility apparatus to pass an 
unsafe distance beyond the boundary strip towards the open staircase 
potentially placing the occupant in a dangerous position before additional 
brake assemblies can be engaged to fully arrest the apparatus. 
It is to an improved mobility apparatus which comprises a braking assembly 
which when first engaged, automatically engages all other braking 
assemblies irrespective of their position with respect to the boundary 
strip that the present invention is directed. 
SUMMARY OF THE INVENTION 
The invention provides an improved mobility apparatus, the improvement 
comprising an optically responsive release mechanism which engages a brake 
assembly and arrests the mobility apparatus. An optically encoded boundary 
strip is placed in front of the staircase or other level drop. As the 
mobility apparatus rolls over the boundary strip, the first brake assembly 
to contact the boundary strip engages and also automatically signals all 
other brake assemblies. In response to this signal, the other brake 
assemblies immediately engage thereby preventing ally substantial mobility 
apparatus movement beyond the boundary strip. 
Each brake assembly consists of an outer cylindrically shaped housing 
having an attached rectangular compartment. A substantially solid wall 
partitions the interior of the housing into an upper and lower chamber. 
The upper chamber contains an audible alarm. The lower chamber contains an 
extendable piston. A compressible spring is disposed between the upper end 
of the piston and the partition wall of the housing. The rectangular 
compartment contains a battery, control printed circuit board and 
solenoid. 
The brake assembly is initially disengaged by forceably inserting the 
piston into the lower chamber against the force exerted by the compressed 
spring. A releaseable latching mechanism locks the piston in this position 
and prevents further vertical piston movement. The solenoid is further 
attached to the latching mechanism. 
The bottom of the piston further contains an infrared emitter and infrared 
detector. The emitter and detector are positioned such that any incident 
emissions from the emitter will reflect off of a parallel aligned 
reflective surface placed beneath the emitter and detector pair which will 
then be subsequently received by the detector. 
As the mobility apparatus rolls over the boundary strip, the bottom end of 
the first brake assembly to engage the strip slides up and over the top of 
the strip. The incident infrared radiation is reflected off of the 
optically encoded top of the strip and is subsequently received by the 
detector which signals the control circuit. In response to this signal the 
control circuit energizes both the audible alarm and solenoid. The 
energized solenoid releases the latching mechanism. The force of the 
compressed spring then forceably extends the piston outwardly from the 
bottom of the housing significantly increasing the amount of surface 
contact friction between the floor surface and mobility apparatus. 
Additionally, immediately upon receiving the detector signal, the control 
circuit of the first brake generates a global brake engage signal which is 
then transmitted by the control circuit to all other brake assemblies. In 
response to this signal, all or the other corresponding solenoids are 
energized releasing all of the other latching mechanisms thereby allowing 
all of the other respective pistons to forceably move in a vertically 
downward direction. 
All brake assemblies are now engaged having the bottom surface of all 
pistons now forceably coming into frictional contact with the top floor 
surface thus quickly arresting the mobility apparatus and preventing any 
further substantial movement beyond the reflective strip. 
The brake assembly further comprises a retractable omnidirectional rotating 
support which minimizes the frictional contact between the brake assembly 
and floor surface during normal mobility apparatus operation. 
OBJECTS OF THE INVENTION 
It is therefore an object of the invention to provide an improved mobility 
apparatus for automatically arresting in front of an open descending 
staircase. 
It is another object of the invention to provide an improved mobility 
apparatus which automatically arrests as the mobility apparatus rolls over 
an optically encoded boundary. 
It is yet a further object of the invention to provide a brake assembly 
responsive to an optically encoded boundary strip placed in front of an 
open staircase for preventing mobility devices from being propelled down 
an open staircase. 
It is yet still a further object of the invention to provide an optically 
responsive brake assembly attached to a mobility apparatus which, at the 
moment of being engaged, automatically activates other similarly attached 
like brake assemblies for minimizing the amount of distance required to 
arrest a moving mobility apparatus. 
It is yet still a further object of the invention to provide an optically 
activated brake assembly having an audible alarm for alerting adults of an 
imminent danger to a child'safety. 
It is yet another further object of the invention to provide an inexpensive 
and easily manufactured brake assembly for preventing a mobility apparatus 
from being inadvertently propelled down an open staircase. 
It is still yet another object of the invention to provide a mobility 
apparatus having a retractable omnidirectional rotating support for 
minimizing the frictional contact between the braking assembly and floor 
surface during normal mobility apparatus operation. 
It is yet another object of the invention to provide a wheel assembly for 
controlling the rolling movement of a mobility apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIG. 1 of the drawings, there is shown a preferred 
embodiment 1 of the present invention comprising a conventionally 
constructed baby walker 5 having a lower support member 6. Upper support 
member 7 connects to and is vertically positioned over lower support 
member 6. Support member 7 further contains seat 8 and an integral 
backrest support 9 to support the occupant of walker 5. Additionally, 
brake assemblies 21a and 21b are moveably attached to support member 6 and 
in contact with tongue and groove floor surface 14. Brake assemblies 21a 
and are similarly constructed and are electrically interconnected via 
wires 123 and 125. Brake assemblies 21a and 2lb are more fully described 
below. 
Rotatably attached to support member 6 are front wheel support assemblies 
10a and rear wheel support assemblies 12a. Front wheels 10 and rear wheels 
12 are rollably attached to their respective wheel support assemblies 10a 
and 12a. Further, wheels 10, 12 are in contact with floor surface 14. 
Wheels 10, and 12, and respective rotatable wheel support assemblies 10a, 
and 12a, enable walker 5 to move unobstructively in all directions on 
floor surface 14 with a minimum amount of friction. Thus, a baby properly 
placed within walker 5 is able to easily propel themselves and traverse 
floor surface 14 in all directions. 
An optically encoded reflective arc shaped strip 15 having respectively 
inside and outside beveled edges 17 and 18 is further attached to floor 
surface 14 using conventional screws 19. Strip 15 could also be attached 
to a smooth floor surface using conventional double sided tape or could be 
placed on top of a carpet covering floor surface 14. Preferably strip 15 
is placed in front of a descending staircase 20 or other level drop such 
as may be encountered with a patio or porch. 
Beveled edges 17 and 18 provide for a smooth transition from floor surface 
14 to top surface 16 of strip 15 thereby allowing walker 5 and brake 
assembly 21a and 21b to smoothly ascend from the floor surface 14 to top 
16 of strip 15 as walker 5 is propelled across strip 15 and also minimally 
hinders normal walking across strip 15. 
Referring now additionally to FIG. 2, brake assembly 21a comprises a 
substantially cylindrical shaped housing 22 having an enclosed top 24, 
outside wall 26 and open bottom 28. Further formed on the right side of 
outside wall 26 is rectangular shaped compartment 100. Affixed to the left 
side of wall 26 is one end of cylindrical shaped pin 30. 
The hollow interior space of housing 22 is separated into upper chamber 32 
and lower chamber 34 by solid disk shaped partition wall 36 parallelly 
aligned with top 24. Upper chamber encloses piezo electric alarm element 
38. Further formed on top 24 is centered through hole 40 which passes 
sound waves 42 generated by energized alarm 38 into the surrounding space. 
Lower chamber 34 encloses cylindrically shaped moveable piston 44 having a 
solid top surface 46. Disposed between the underside of wall 36 and the 
outside of top surface 46 is compressed spring 48. The outside diameter of 
piston 44 is slightly less in dimension than the inside diameter of wall 
26 thus permitting piston 44 to unobstructively slide within lower chamber 
34. Further formed on outside wall 26 of lower chamber 34 is through hole 
50 and oppositely disposed through hole 52. 
Referring now to interior portion 54 of piston 44, there is shown a 
cylindrically shaped blind hole 56 extending radially inwards from the 
outside wall of piston 44. Inserted into hole 56 is cylindrically shaped 
pin 58. The outside diameter of pin 58 is slightly less in dimension than 
the inside diameter of hole 56 thus allowing pin 58 to unobstructively 
move within hole 56. Positioned within hole 56 is compression spring 60 
having one end abutted against the interior end surface of hole 56 and the 
other end engaging the interior end surface of pin 58. It is therefore 
understood that with pin 58 inserted into hole 56 spring 60 applies an 
outwardly directed force against pin 58. The exterior end surface of pin 
58 has further formed triangularly shaped nib 62. With piston 44 forceably 
inserted and fully seated into mousing 22, nib 62 engages hole 50. Further 
shown within interior portion 54 is cylindrically shaped blind hole 64 
oppositely disposed from, and axially aligned with, hole 56. The diameter 
of hole 64 equals the diameter of hole 50. 
Formed on the lower portion of piston 44 is circumferential flange 66 
having beveled edge 68. Within interior portion 70 of piston 44, there is 
shown a cylindrically shaped blind hole 72 extending vertically upwards 
from piston bottom surface 74 into the interior of flange 66. Inserted 
into hole 72 is cylindrically shaped cup 76 containing ball 78. Cup 76 
supports and allows free rotation of ball 78. The diameter of cup 76 is 
slightly less than the diameter of hole 72 allowing cup 76 to move 
vertically within hole 72. Compression spring 80 is disposed between the 
top surface of cup 76 and the interior top surface of hole 72. The depth 
of hole 72 further permits the complete retraction of the entire cup 76 
and ball 78 into the interior of hole 72. The bottom surface of ball 78 
contacts top surface of floor 14. It is therefore understood that hole 72, 
cup 76, spring 80 and ball 78 comprise a springably affixed, retractable 
omnidirectional rotating support for brake assembly 21a. Ball 82 also 
provides a similarly constructed retractable support for brake assembly 
21a. 
Referring now to lower central interior portion 84 of piston 44, there is 
shown exteriorly opened, cylindrically shaped cavity 86 containing 
infrared light emitting diode 88. Diode 88 is positioned within cavity 86 
to emit a focused narrow beam of infrared light 90 out of cavity 86. 
Oppositely disposed from cavity 86 is a similarly constructed cavity 92 
containing a cooperating infrared photodetector 94. Photodetector 94 is 
positioned within cavity 92 to receive reflected infrared light 96 from 
the exterior underside of piston 44. Cavities 86 and 92 are aligned in 
such a manner so as to allow focused incident infrared light 90 emitted by 
diode 88 to reflect off of a reflective surface placed beneath and 
parallel to the bottom of underside surface 74 thereby producing reflected 
infrared light 96 which is then captured by photodetector 94. 
Referring now to compartment 100, there is shown enclosed within 
compartment 100 conventional solenoid 102, battery 104 and control circuit 
106. Control circuit 106 further comprises printed circuit control board 
107 which secures and interconnects various electronic components (not 
shown), reset switch 120, output signal connector 122 and input signal 
connector 124, LED low battery indicator 125 and ON/OFF switch 105. 
Switches 105 and 120, connectors 122 and 124, and indicator 125 are all 
exteriorly accessible. 
Solenoid 102 further comprises moveable cylindrically shaped plunger 108 
partially enclosed by a cylindrically shaped coil 109. Formed on the end 
exterior portion of plunger 108 is flange 110. Axially positioned around 
the exterior of plunger 108 and between the body of solenoid 102 and 
flange 110 is compressed spring 112. The exterior end of plunger 108 has 
further formed a triangularly shaped nib 114 similar to nib 62. The 
diameter of plunger 108 further equals that of pin 58. With plunger 108 
fully extended and with piston 44 inserted and fully seated within housing 
22, the exterior end of plunger 108 passes through hole 52 with nib 114 
engaging hole 64. 
Thus it is understood that with piston 44 forceably and fully seated within 
housing 22, holes 50, 56, 64 and 52 are all axially aligned, nib 62 
springably engages hole 50, and, with plunger 108 extended, nib 114 
springably engages hole 64 thereby latching piston 44 within housing 22. 
Housing 22 is further inserted into, and supported in a vertical direction 
by, cylindrically shaped bracket 116 which is affixed to lower support 
member 6 of mobility apparatus 5. Bracket 116 has further formed a 
vertically disposed through slot 118. Pin 30 extends from wall 26 through 
slot 118. The inside diameter dimension of bracket 116 is larger than the 
outside diameter dimension of housing 22. Thus housing 22 is free to 
vertically move within bracket 116 a distance determined by the length of 
slot 118. Thus brake assembly 21a is moveably attached to the mobility 
apparatus as previously described in my aforesaid co-pending application 
and can vertically move a predefined distance equal to the vertical length 
of slot 118. 
Referring now additionally to FIG. 3, there is shown a schematic diagram of 
control circuit 106 positioned over reflective strip 15 and which 
substantially comprises low battery detector 126, microcontroller 128, 
output connector 122, input connector 124, reset SPST push button switch 
120, diode 140, and power MOSFET transistor 138. Control circuit 106 is 
also generally shown connected to alarm element 38, solenoid coil 109, 
infrared emitting diode 88 and infrared photodetector 94. Battery 104 
supplies voltage Vbat to control circuit 106 and alarm element 38 via 
ON/OFF switch 105. 
Microcontroller 128 is a conventional 8 bit microcontroller integrated 
circuit such as a Motorola Semiconductor 68HC05K having random access 
memory (RAM) 130, read only memory (ROM) 132, and programmable 
input/output port pins through . ROM 132 contains a program which 
controls the operation of microcontroller 128. RAM 130 is used for 
temporary storage of Program variables and input/output signals for port 
pins -. Additionally, RAM 130 includes two 8 bit registers Cntr1-and 
Cntr2 used as binary counters, two 8 bit registers Cntr-1 and Cntr-2 to 
respectively store the previous values of counters Cntr1 and Cntr2, and 
another 8 bit register having a single bit used as a test ("T") flag. 
Included but not shown is a crystal timing network which generates the 
clock signal for microcontroller 128. 
Referring now to the specific connections to microcontroller 128, output 
pin connects to the control terminal of alarm element 38. Alarm 
element 38 further connects to battery voltage Vbat and ground. Alarm 38, 
in response to having the voltage at pin set equal to Vbat, produces 
audible alarm sounds 
Output pin connects to one terminal of output connector 122. The second 
terminal of connector 122 connects to ground. Input pin connects to 
one terminal of input connector 124. The second terminal of connector 124 
connects to ground. Connectors 122 and 124 respectively send and receive 
signals from another similarly constructed brake assembly 2lb. Output 
connector 122 of brake assembly 21a is connected via wire 123 to the 
corresponding input connector of brake assembly 2lb and the corresponding 
output connector of brake assembly 2lb is connected via wire 125 to input 
connector 124 of brake assembly 21a. This interlinking connection may be 
expanded to include any number of additional similarly constructed brake 
assemblies having the output of the first brake assembly connect to the 
input of the second brake assembly, the output of the second brake 
assembly connect to the input of the third brake assembly etc. This 
pattern is repeated until the output of the last brake assembly connects 
to the input of the first brake assembly. 
Input pin connects to one terminal of SPST push button reset switch 
120. The second terminal of switch 120 connects to battery voltage Vbat. 
Thus depressing switch 120 connects voltage Vbat to input Din . 
Output pin connects to the gate terminal of MOSFET switch transistor 
138. The source terminal of transistor 138 connects to ground. The drain 
terminal of transistor 138 connects to both the anode of diode 140 and one 
end of coil 109. The other end of coil 109 and the cathode of diode 140 
both connect to battery voltage Vbat. Placing a voltage onto pin 
causes transistor 138 to turn-on which allows current to flow from battery 
104 through coil 109 to ground producing magnetic field 109a which in turn 
pulls plunger 108 into solenoid 102. Input pin connects to both one 
terminal of pull-up resistor 136 and the collector of phototransistor 94. 
The second terminal of resistor 136 connects to battery voltage Vbat. The 
emitter of phototransistor 94 connects to ground. With no infrared light 
impinging upon photodetector 94, photodetector 94 remains in the off 
condition preventing current flow through resistor 136 and thereby 
maintaining the signal on pin at voltage Vbat. With infrared light 96 
impinging upon photodetector 94, photodetector 94 turns on and allows 
current flow from Vbat through resistor 136 thereby forcing the voltage on 
pin to ground. Thus a low or high signal on pin of controller 128 
is respectively indicative of photodetector 94 receiving or not receiving 
infrared light 96. 
Output pin connects to one terminal of current limiting resistor 134. 
The other end of resistor 134 connects to the cathode of infrared diode 
88. The anode of diode 88 is connected to battery voltage Vbat. With pin 
held at voltage Vbat, no current flows through diode 88 and therefore 
no infrared light is emitted. However, with pin placed at ground, 
current flows from battery voltage Vbat through diode 88 and resistor 134 
generating infrared light 90. Thus controller 128 controls the generation 
of pulses of infrared light 90 by pulsing the polarity of pin between 
Vbat and ground. 
Input pin connects to conventional low battery voltage detector 126 via 
line 127. Low battery voltage detector 126 continually samples voltage 
Vbat and, in response to Vbat decreasing below a predetermined threshold, 
places a signal onto line 127 which flows to controller 128. Light 
emitting diode 125 connects to detector 126 and is illuminated when a low 
battery voltage condition exists. 
Referring now specifically to reflective strip 15, it is shown that top 
surface 16 comprises parallelly aligned non reflective bands 2a, 2b, 2c 
and 2d, each of which is separated from one another by reflective bands 
3a, 3b, 3c, and 3d. Thus the exteriorly exposed top surface of strip 15 
comprises an alternating pattern of reflective and non reflective bands 
which extend the entire length of strip 15. Non reflective bands 2a-2d 
absorb and dissipate all emitted light 90, and therefore do not reflect 
any light 90 emitted by diode 88, while in comparison, reflective bands 
3a-3b reflect any infrared light 90 emitted by diode 88. Further, the 
widths of non reflective bands 2a-2d equal the widths of reflective bands 
3a-3d. 
In operation and initially assuming that piston 44 has been first inserted 
and latched into housing 22 thereby disengaging brake assembly 21a, baby 
walker 5 freely traverses floor surface With piston 44 latched into 
housing 22, the retractable supports associated with balls 78 and 82 
prevent surface 74 from frictionally contacting surface 14. Brake assembly 
21a therefore freely traverses floor surface 14 having balls 78 and 82 
rollably supporting brake assembly 21a. Additionally, brake assembly 21a 
also freely moves in a vertical direction a distance defined by the length 
of slot 118. Brake assembly 21b is also similarly disengaged. It is 
therefore understood that disengaged brake assemblies 21a and 21b 
minimally hinder the omnidirectional movement of mobility apparatus over 
floor surface 14. With brake assembly 21a disengaged, switch 105 is then 
placed in the 0N position activating brake assembly 21a and supplying 
voltage Vbat to control circuit 106 and alarm element 38. A corresponding 
ON-OFF switch on brake assembly 21b is also placed in the 0N position. 
Referring now additionally to FIGS. 4-6, there is in combination shown a 
flow chart of the program steps controlling the operation of 
microcontroller 128. This program is stored in ROM 132. A similar program 
is stored within the corresponding ROM memory of brake assembly 21b. 
Within the following discussion, any program steps referring to brake 
assembly 21b are noted with a preceding asterisk. For example, step 202 is 
associated with brake assembly 21a and step 202 is associated with brake 
assembly 21b. 
As voltage Vbat is first applied via switch 105, microcontroller 128 begins 
operation at step 150 in which microcontroller 128 initializes the various 
CPU registers and RAM 130 memory locations for continued operation. 
Additionally, counters Cntr1 and Cntr2 and registers Cntr-1 and Cntr-2 are 
reset. Further, microcontroller 128 programs the I/O port pins and 
establishes pins , , and as outputs and pins , , 
and as inputs. Microcontroller 128 then resets output pins , 
and to ground and sets output pin to voltage Vbat. With pin at 
ground, alarm 38 is deactivated and does not produce alarm sounds 42. With 
pin at ground, a "brake assembly not engaged" signal is transmitted to 
brake assembly 21b. Further, with pin at ground transistor 138 is 
turned maintaining solenoid 109 in the non-energized state with nib 114 
engaging hole 64. Also, with pin at voltage Vbat diode 88 is turned 
off. Microcontroller 128 then proceeds to step 152. 
Within step 152, microcontroller 128 places pin to ground (resets pin 
) enabling current flow through diode 88 and resistor 134. In response 
to this current flow, diode 88 turns on and emits focused infrared light 
90 from cavity 86. Microcontroller 128 then proceeds to step 154. 
Within step 154, microcontroller 128 inputs the voltage which is placed 
onto pin and stores the logical equivalent signal into RAM 130. If 
incident infrared light 90 is reflected off of a parallel aligned 
reflective surface placed beneath diode 88 and photodetector 94 producing 
reflective infrared light 96, photodetector 94 turns on and conducts 
current which then flows through resistor 136 thereby placing the voltage 
on pin near ground. If a non parallel aligned reflective surface, or a 
parallel aligned non reflective surface is present beneath diode 88 and 
photodetector 94, photodetector 94 is off and no current flows thereby 
placing the voltage on pin at Vbat. Thus the signal placed on pin 
equals a logic 0 if infrared light is reflected and subsequently received 
by photodetector 94 or equals a logic 1 if infrared light is not received 
by photodetector 94. Microcontroller 128 then proceeds to step 156. 
Within step 156, microcontroller 128 sets pin to voltage Vbat 
preventing current flow through diode 88 and resistor 134 thus turning off 
diode 88. Thus diode 88 is pulsed on for only a short time interval equal 
to the time necessary for microcontroller 128 to complete steps 152, 154 
and 156 thus minimizing power consumption from battery 104. 
Microcontroller 128 then proceeds to step 158. 
Within step 158, microcontroller 128 then evaluates the signal on pin 
previously determined in step 154 and, if the signal equals a logic 0 
(infrared light detected), branches to step 180. If the signal on pin 
equals a logic 1 (infrared light not detected), microcontroller 128 
branches to step 160. The following discussion now refers to steps 160 
through 174. 
Within step 160, microcontroller 128 copies the current value of counter 
Cntr1 into register Cntr-1. Microcontroller 128 then proceeds to step 162 
in which microcontroller 128 compares the value of register Cntr-1 to 0. 
If the value of register Cntr-1 equals 0, microcontroller 128 branches to 
step 172. If the value of register Cntr-1 does not equal 0, 
microcontroller 128 proceeds to step 164. Within step 164, microcontrol 
let 128 compares the value of register Cntr-2 to 0. If the value of 
register Cntr-2 equals 0, microcontroller 128 branches to step 172. If the 
value of register Cntr-2 does not equal 0, microcontroller 158 proceeds to 
step 166. Thus, steps 165 and 164 respectively check for either Cntr-1 or 
Cntr-2 register values equalling 0 and branches accordingly to step 172. 
Within step 166, microcontroller 128 calculates the ratio of the value of 
register Cntr-1 to the value of register Cntr-2. Microcontroller 128 then 
compares this calculated ratio to determine if it lies between two 
predetermined constants N1 and N2. If the calculated ratio is between N1 
and N2, microcontroller 128 branches to step 204. If the calculated ratio 
is not between N1 and N2, microcontroller 128 continues to step 168. Note 
that division by zero (Cntr-2 equals 0) is prevented by step 164. N1 and 
N2 are respectively equal to 0.8 and 1.2. 
Within step 168, microcontroller 128 compares the value of the T flag to 0. 
If the T flag equals 0, microcontroller 128 then proceeds to step 170. If 
the T flag does not equal 0, microcontroller 128 proceeds to step 174. 
Within step 170, microcontroller 128 resets Cntr2 and proceeds to step 
172. Within step 172, microcontroller 128 then sets the T flag to 1 and 
proceeds to step 174. The logical value of the T flag is used to determine 
the occurrence of the first initial pass through the sequence of steps 152 
through 158 and continuing through step 168 in which counter Cntr2 is 
reset. 
Within step 174, microcontroller 128 increments the value of counter Cntr2. 
Operation of microcontroller 128 then proceeds to step 196. 
Referring now back to step 180 (infrared light detected), microcontroller 
128 copies the current value of counter Cntr2 into register Cntr-2. 
Microcontroller 128 then proceeds to step 182. 
Within step 182, microcontroller 128 compares the value of register Cntr-2 
to 0. If the value of register Cntr-2 equals 0, microcontroller 128 
branches to step 192. If the value of register Cntr-2 does not equal 0, 
microcontroller 128 proceeds to step 184. Within step 184, microcontroller 
128 compares the value of register Cntr-1 to 0. If the value of register 
Cntr-1 equals 0, microcontroller 128 branches to step 192. If the value of 
register Cntr-1 does not equal 0, microcontroller 128 proceeds to step 
186. 
Within step 186, microcontroller 128 calculates the ratio of the value of 
register Cntr-1 to the value of register Cntr-2. Microcontroller 128 then 
compares this calculated ratio to determine if it lies between the two 
predetermined constants N1 and N2. If the calculated ratio is between N1 
and N2, the microcontroller branches to step 204. If the calculated ratio 
is not between N1 and N2, microcontroller 128 continues to step 188. 
Within step 188, microcontroller 128 compares the value of the T flag to 1. 
If the T flag equals 1, microcontroller 128 then proceeds to step 190. It 
the T flag does not equal 1, microcontroller 128 proceeds to step 194. 
Within step 190, microcontroller 128 resets counter Cntr1 and proceeds to 
step 192. Within step 192, microcontroller 128 then resets the T flag and 
proceeds to step 194. The logical value of the T flag is again used to 
determine the occurrence of a first initial pass through the sequence of 
steps 152 through 158 and continuing through step 188. Note that the T 
flag has been set in the previously executed step 172. 
Within step 194, microcontroller 128 increments the value of counter Cntr1. 
Operation of microcontroller 128 then proceeds to step 196. 
Within step 196, microcontroller 128 inputs the signal on pin and 
determines if the corresponding logic value equals 1(battery voltage is 
sufficient) or 0 (battery voltage is not sufficient). If the logic value 
of pin equals 1, microcontroller 128 proceeds to step 200. If the 
logic value of pin equals 0, microcontroller 128 branches to step 204. 
Within step 200, microcontroller 128 delays continued operation for a 50 
microsecond time interval. Operation of microcontroller 128 then proceeds 
to step 202. 
Within step 202, microcontroller 128 inputs the signal on pin which 
originates from brake assembly 21b corresponding output connector. If the 
signal on pin equals a logic 1 indicating that brake assembly 21b has 
been previously engaged, microcontroller 128 then proceeds to step 204. If 
the signal on pin equals a logic 0 indicating that brake assembly 21b 
is still disengaged, microcontroller 128 branches back to step 152 to 
begin another cycle. 
Thus generally, as walker 5 continually traverses a reflective floor 
surface such as a highly polished hardwood or linoleum floor surface, 
microcontroller 128 follows steps 152 through 158, branches to step 180 
and continues through step 202 and then branches back to step 152 
continually cycling through this sequence of steps (reflective cycle) 
until a non reflective surface is detected in step 158. For the initial 
first cycle beginning with step 152 through step 158 and continuing 
through step 190, the value of counter Cntr1 is reset. Counter Cntr1 is 
then incremented and, for each contiguous succeeding cycle, the value of 
counter Cntr1 is further incremented. Thus the value of counter Cntr1 
indicates the number of infrared pulses received by photodetector 94 for a 
given reflective, properly aligned surface. 
Similarly, if walker 5 continually traverses a non reflective floor surface 
such as a rug covered surface, microcontroller 128 again follows steps 152 
through 158 but now branches to step 160 (infrared light not detected) and 
continues through step 202 and then again branches back to step 152 
continually cycling through this alternative sequence of steps (non 
reflective cycle) until a reflective surface is detected in step 158. For 
the initial first cycle beginning with step 152 through step 158 and 
continuing through step 170, the value of counter Cntr2 is reset. Counter 
Cntr2 is then incremented and, for each contiguous succeeding cycle, the 
value of counter Cntr2 is further incremented. Thus the value of counter 
Cntr2 indicates the number of infrared pulses not received by 
photodetector 94 for a given non reflective surface. 
Thus as walker 5 alternately traverses from a reflective to non reflective 
floor surface 14 and vice versa, microcontroller 128 respectively 
alternates between the reflective cycle and non reflective cycle and vice 
versa. For each reflective or non reflective cycle in which both Cntr-1 
and Cntr-2 registers are not equal to zero, microcontroller 128 determines 
if the ratio of the immediately previous value of counter Cntr1 (i.e. 
Cntr-1) to the immediately previous value of counter Cntr2 (i.e. Cntr-2) 
is between the predetermined limits N1 and N2. Only a narrow range of 
values of received and non received infrared pulses will cause their ratio 
to be between the predetermined limits of N1 and N2. Thus, it is therefore 
understood that in normal operation of walker 5, the ratio of the values 
of Cntr-1 to Cntr-2 will not be between the predetermined limits N1 and N2 
and thus microcontroller 128 will continue within the respective 
reflective or non reflective cycles thereby not engaging brake assemblies 
21a and 21b. 
Now assume that walker 5 proceeds towards an open descending staircase 20 
having an optically encoded strip 15 secured onto floor surface 14 in 
front of the staircase entrance. Upon walker 5 approaching open staircase 
20 and forwardly passing over strip 15, front wheels 10 and 11 easily roll 
up over beveled edge 18 onto top 16 and down inside beveled edge 17 or 
strip 15. As walker 5 continues to be propelled towards open staircase 20, 
beveled edge 68 of brake assembly 21a eventually contacts outside beveled 
edge 18 of strip 15. Further forward motion of walker 5 towards open 
staircase 20 causes beveled edge 68 to smoothly ascend along outside 
beveled edge 18 thereby moving brake assembly 21a vertically with respect 
to support member 6. Brake assembly 21a is guided by pin 30 within slot 
118 and freely moves in the vertical direction without impeding the 
forward motion of walker 5. As brake assembly 21a ascends edge 18, 
incident infrared light 90 is reflected off of the inclined edge 18 but 
not at the proper angle to activate photodetector 
Further forward motion of walker 5 over strip 15 eventually positions 
emitting diode 88 and photodetector 94 over reflective strip 3d. The 
incident infrared light 90 is now reflected off of strip 3d at the proper 
angle and received by photodiode 94. Thus microcontroller 128 begins a new 
reflective cycle (3d). Further forward motion of walker 5 eventually 
positions emitting diode 88 and photodetector 94 over non reflective strip 
2d which then causes microcontroller 128 to begin a new non reflective 
cycle (2d). Non reflective cycle (2d) continues until the continued 
forward motion of walker 5 positions emitting diode 88 and photodetector 
94 over non reflective strip 3c and which causes microcontroller 128 to 
begin another reflective cycle (3c). At this point register Cntr-1 has 
been updated with the value of counter Cntr1 obtained from strip 3d and 
register Cntr-2 has been updated with the value of counter Cntr2 obtained 
from strip 2d. Now at this point the values of register Cntr-1 and 
register Cntr-2 will be approximately the same because the widths of the 
reflective and non reflective bands are equal and therefore the ratio of 
the value of register Cntr-1 to the value of register Cntr-2 will be 
between N1 and N2. 
Referring now additionally to FIG. 7, there is shown the reflective and non 
reflective register values respectively of Cntr-1 and Cntr-2 for both a 
slow and a fast moving walker 5 over strip 15. Although the absolute 
numbers for registers Cntr-1 and Cntr-2 for the slow moving walker 5 are 
greater than the absolute numbers of the same registers for the fast 
moving walker 5, the ratio of the value of register Cntr-1 to the value of 
register Cntr-2 remains the same for either a fast or slow moving walker 5 
as the result of equal widths for the reflective and non reflective bands. 
Thus, the ratio, and therefore the determination of whether walker 5 has 
traversed strip 15, is independent of the speed of walker 5. 
Microcontroller 128, having now determined that the ratio is between N1 
and N2, branches to step 204 thereby engaging brake assembly 21a. 
Within step 204, microcontroller 128 sets pin high which enables alarm 
element 38 producing alarm sounds 42. Further, microcontroller 128 sets 
pin high which is then communicated via output connector 122 and line 
123 to the corresponding input connector on brake assembly 21b. 
Additionally, microcontroller 128 sets pin high which turns on 
transistor 138. With transistor 138 on, current flows from Vbat through 
solenoid coil 109 through transistor 138 to ground. 
In response to current flow, coil 109 produces a magnetic field 109a which 
pulls plunger 108 into the interior of solenoid 102 and against the force 
exerted by compression spring 112 thereby retracting nib 114 from hole 64. 
With nib 114 retracted, spring 60 of oppositely positioned pin 58 is 
unable to now counter the entire horizontal force component exerted by 
spring 48 through the triangularly shaped nib 62. Pin 58 is subsequently 
forced into hole 56 compressing spring 60 thereby disengaging nib 62 from 
hole 50. Piston 44 now comes under the direct force of compressed spring 
48 and forceably moves outwardly from the bottom of housing 22. 
As piston 44 moves in a vertically downward direction from housing 22, ball 
78 and cup 76 are forced to retract into hole 72 of flange 66 against the 
force of spring 80. Ball 82 and the respective supporting cup also 
retracts into flange 66. With balls 78 and 82 fully retracted within 
flange 66, bottom surface 74 comes into frictional contact with floor 
surface 14. The force of compressed spring 48 acting through piston 44 and 
floor surface 14 now proceeds to displace housing 22 vertically until pin 
30 contacts the top of slot 118. At this moment the force of compressed 
spring 48 acting now through piston 44, floor surface 14 and housing 22 
proceeds to vertically displace in an upwards direction support member 6 
from floor surface 14 thus substantially increasing the frictional contact 
between mobility apparatus 5 and floor surface 14 and lifting wheels 10 
and 11 off of floor surface 14. 
Brake assembly 21b within its corresponding reflective or reflective cycle 
will eventually check the value of the signal placed onto line 123 by 
brake assembly 21a via a corresponding step *202. In response to the 
signal placed onto line 123, a corresponding step *204 is executed 
engaging brake assembly 21b furthering the frictional contact between 
mobility apparatus 5 and floor surface 14. Additionally, brake assembly 
21b within step *204 communicates to brake assembly 21a the fact that it 
has engaged by placing a logic 1 signal onto pin *. With brake assembly 
21a now engaged, microcontroller 128 proceeds to step 208. 
Within step 208, microcontroller 128 continually checks the logic value of 
the signal placed on pin via line 125 by brake assembly 21b until 
brake assembly 21b has engaged. Microcontroller 128 then proceeds to step 
210. Thus brake assembly 21a, having engaged, transmits a brake engage 
signal via line 123 to brake assembly 21b. In response to this signal, 
brake assembly 21b also engages and thereafter confirms this fact by 
placing a logical 1 signal onto line 125. 
Within step 210, microcontroller 128 inputs the signal on pin to 
determine if reset switch 120 has been depressed. If the signal on pin 
is high (reset switch 120 depressed), microcontroller 128 proceeds to step 
214. If the signal on pin is low (reset switch 120 not depressed), 
microcontroller 128 proceeds to step 212. Within step 212, microcontroller 
128 further determines if a logic 0 signal has been received on pin 
via line 125 and input connector 124 originating from the corresponding 
output connector of brake assembly 21b. If the signal on pin is 
maintained at logic 1 indicating that brake assembly 21b has not been 
reset, microcontroller 128 proceeds back to step 210. If a logic 0 signal 
is present on pin , microcontroller 128 proceeds to step 214. Thus 
microcontroller 128 proceeds to step 214 either if reset switch 120 is 
depressed or if a logic 0 signal is input from brake assembly 21b. 
Within step 214, microcontroller 128 shuts off alarm element 38 by 
resetting pin , resets pin which is then transmitted to the 
corresponding input connector of brake assembly 21b via connector 122 and 
line 123, and deactivates solenoid 102 by resetting pin which 
subsequently forces transistor 138 to turn off thereby preventing current 
flow through coil 109. As coil 109 becomes deenergized, diode 140 prevents 
large voltage spikes from occurring across the coil terminals. Brake 
assembly 21b, in response to a logic 0 signal placed onto line 123, now 
branches to step 214* and proceeds in a similar fashion as brake assembly 
21a. Microcontroller 128 then proceeds to step 220. 
Within step 220, microcontroller 128 enters a delay of preferably 60 
seconds to enable the parent or other guardian sufficient time to manually 
disengage brake assembly 21a and any other similarly engaged brake 
assemblies. After the delay of step 220, microcontroller 128 then proceeds 
back to step 152 to again begin another new reflective or non reflective 
cycle. 
To disengage brake assembly 21a, the parent or guardian forceably reinserts 
piston 44 back into housing 22 against the force of spring 48. With piston 
44 fully inserted and seated within housing 22, pin 58 is forced outwardly 
from hole 56 by the force of spring 60 thereby extending nib 62 into hole 
50. Similarly, with solenoid 102 deactivated and piston 44 fully inserted, 
plunger 108 is forced outwardly from solenoid 102 by spring 112 pushing 
against flange 110 and the body of solenoid 102 thereby extending nib 114 
into hole 64. With nib 62 and nib 114 fully inserted into respective holes 
50 and 64, piston 44 is now again latched within housing 22. Brake 
assembly 21b is similarly disengaged. 
Referring now to FIG. 8, there is shown another embodiment of the present 
invention in which two or more wheel support assemblies 10a or 12a, could 
alternatively have formed cylindrically shaped brackets 116' for moveably 
attaching brake assemblies 21a and 21b. Bracket 116' serves the same 
function as bracket 116. Further, the hard wiring interconnection has been 
replaced with a conventional cooperating RF transcievers thus eliminating 
the possibility of fouling the wheel or wheel support assemblies with the 
interconnecting wires. It is thus understood that brake assemblies 21a and 
21b could each be moveably attached to individual wheel support assemblies 
instead of support member 6 without altering the operation thereof. 
While specific embodiments of the invention have been described in detail, 
it will be appreciated by those skilled in the art that various 
modifications and alternatives to those details could be developed in 
light of the overall teachings of the disclosure. For example, although 
the present invention describes a separate microcontroller for each brake 
assembly 21a and 21b, a single microcontroller could be used to control 
both the infrared emitting and detection for both brake assemblies and 
also the respective solenoids. Further, the hard wired communication link 
between brake assembly 21a and 21b when attached to support member 6 could 
also be replaced with conventional cooperating RF or ultrasonic 
transcievers. Additionally, the infrared emitting diode could be replaced 
with a conventional laser emitting diode. Accordingly, the particular 
arrangements disclosed are meant to be illustrative only and not limiting 
as to the scope of the invention which is to be given the full breadth of 
the appended claims and any and all equivalents thereof.