Baby walker having safety interlock

A walker for an infant or incapacitated adult which includes a frame work dimensioned and configured for placement around the user having an upper member dimensioned to enable the user to support him or herself and a lower member encircling the legs of the user, the upper and lower members being disposed in spaced relationship. The apparatus also includes a plurality of wheels carried on the second member at spaced parts thereof and apparatus for locking the wheels responsive to passage of the walker into a predetermined zone of danger. In some forms of the invention the apparatus for locking includes a apparatus contacting the circumference of each of the wheels. The wheels may be caster wheels and the apparatus for locking may include a plurality of holes in the circumference of each wheel and a pin dimensioned and configured for engaging the holes. The apparatus for locking may include a cable connected to each pin for limiting axial motion thereof. The apparatus for locking may include a receiver for receiving a signal and a transmitter for sending a signal which may be for a radio frequency signal. The apparatus may also include apparatus for sensing movement of the walker into a predetermined zone of danger.

BACKGROUND OF THE INVENTION 
The invention relates to baby walkers and the like and more particularly to 
devices for preventing movement of such walkers into zones of danger such 
as the top of a stairway. The United States government estimates that in 
1991 there were 30,000 stroller accidents in the United States that 
required emergency room treatment of an infant. The problem is so severe 
that consideration has been given to a ban on the sale of such apparatus. 
The typical walker supports an infant sufficiently so that the infant can 
move on two feet about a floor. A typical scenario leading to death or 
serious injury includes an infant moving toward the top of a stairway and 
toppling down the stairway. While the invention has particular application 
to walkers intended for infants, it will be understood that it may also 
have application for walkers intended for elderly people or other 
suffering from physical disabilities making it difficult for that person 
to walk in a conventional manner. More particularly, the invention will 
have application, for example, for use with elderly people who may suffer 
both from inadequate physical strength to enable them to walk in a 
conventional manner as well as a handicaps resulting from Parkinson's 
disease or other mental disabilities. 
The dangers inherent in stairs are not the only dangers that an infant or 
adults may be exposed to in using a walker. It may be undesirable, for 
example, for the person utilizing the walker to pass into a specific room, 
such as the kitchen, because of the presence of dangerous materials such 
as lye used to clean the traps in the drains from kitchens sinks as well 
as other poisonous or harmful materials. In other cases it may be 
desirable to prevent the infant or person from entering a given room 
because of the potential for damage some delicate electronic equipment or 
other work product that is disposed in a given room. 
The know stroller apparatus has no constraints on the movement of the 
stroller. 
SUMMARY AND OBJECTS OF THE INVENTION 
It is an object of the present invention to provide apparatus which will 
lock the wheels of a walker to limit the movement of the walker upon 
passage of the walker into a zone of danger. 
Another object of the invention is to provide control over the actuation of 
the locking action whereby the actuation occurs when the walker moves into 
a zone of danger. 
It is another object of the invention to provide apparatus that will also 
provide an audible alarm if the walker passes into a zone of danger. 
Still another object of the invention is to provide apparatus which is 
simple and inexpensive to manufacture. 
Still another object of the invention is to provide apparatus which will be 
inexpensive to manufacture. 
Yet another object of the invention is to provide apparatus which is easy 
to install on virtually any automobile. 
It has been found that these and other objects of the invention may be 
attained in a walker for an infant or incapacitated adult which includes a 
frame work dimensioned and configured for placement around the user having 
an upper member dimensioned to enable the user to support him or herself 
and a lower member encircling the legs of the user, the upper and lower 
members being disposed in spaced relationship. The apparatus also includes 
a plurality of wheels carried on the second member at spaced parts thereof 
and means for locking the wheels responsive to passage of the walker into 
a predetermined zone of danger. 
In some forms of the invention the means for locking includes a means 
contacting the circumference of each of the wheels. The wheels may be 
caster wheels and the means for locking may include a plurality of holes 
in the circumference of each wheel and a pin dimensioned and configured 
for engaging the holes. The means for locking may include a cable 
connected to each pin for limiting axial motion thereof. The means for 
locking may include a receiver for receiving a signal and a transmitter 
for sending a signal which may be for a radio frequency signal. The 
apparatus may also include means for sensing movement of the walker into a 
predetermined zone of danger. 
In some embodiments of the invention the means for locking includes a 
solenoid disposed at each caster wheel, each solenoid including a pin for 
engaging one of the caster wheels.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIGS. 1-6 there is shown a walker 10. This walker 10 is a 
generally box-like structure intended to substantially surround the body 
of the user. The box-like structure 10 includes generally planar generally 
square upper surface 11 having an opening 12 through which the torso of 
the user extends. The generally planar surface 11 is supported on four 
columns 14 disposed at each corner of the planar surface 11. Each column 
14 is generally vertical although it will be seen in the preferred 
embodiment, each column 14 has the lower extremity thereof disposed 
further away from the geometric center of the structure 10 than the upper 
axial extremity thereof. It will be clear to those skilled in the art that 
it is desirable that the base of the walker be larger than the top to 
maximize the stability and reduce the possibility of the walker turning 
over when it is being used. The lower axial extremities of the columns 14 
are joined together by a generally rectangular ring 16 that join 
respective adjacent columns 14. Carried on mounting brackets 18 are 
respective casters 20 at the corners of the ring 16. This structure is 
described to this point is conventional and is subject to the deficiencies 
described in the background of the invention section of this application. 
In the preferred embodiment, there is provided a locking mechanism to lock 
the wheels of the respective casters 20 upon movement of the walker 10 
into a zone of danger. The basic concept is to lock the respective wheels 
20 of the respective casters 18a by a latching mechanism which engages the 
respective wheels 20 to prevent their rotation and thus prevent the user 
from urging the walker 10 from the position at the time of initiation of 
the locking movement. It will be understood that the infant who uses a 
typical walker 10 does not have sufficient strength in his or her legs to 
walk without the aid of a walker. Accordingly, such an infant cannot 
readily make the walker 10 move if the wheels 20 do not rotate. Therefore, 
if the respective wheels of the casters 20 are locked so that they will 
not rotate, the typical user will be unable to move the walker 10 further 
into the zone of danger. 
In one preferred form of the invention, flexible cables 30 extend from each 
caster 18a to a common angle iron member 32. Each cable 30 includes an 
outer sleeve. Such cables are sometimes referred to as Bolen cables and 
are of the same general type as those used to shift gears in common 10 
speed bicycles. The cables 30 are utilized to selectively allow pins 34 to 
enter into one of several recesses 36 in each wheel 20 which is part of 
each caster 18a. More specifically, each pin 34 includes a flange 34a that 
slides within a respective cup 40 that is fixed to a respective bracket 
18. A coil spring 41 is disposed between the flange 34a and the cup 40 to 
bias the pin 34 toward the holes 36 in the wheel 20. 
The angle iron member 32 secures the outer sleeve that is part of each 
cable 30. Each sleeve of each cable 30 is also fixed to one of four plates 
42 fixed to the ring 16 near each of the casters 18a. The inner wire of 
each cable 30 is fixed at one end to a T-shaped head 50 and at the other 
end to one of the pins 34. The T-shaped head 50 is fixed to a slide 54 
that is dimensioned and configured to slide readily in a track defined by 
opposed side walls 56, 56. 
A spring biased latch 58 engages the slide 54 and holds the slide in a 
"cocked" position with the four springs 41 compressed and thus urging the 
inner wires of each of the cables 30 to move within the respective sleeves 
thereof. A solenoid 60 is provide to trip the latch 58 by moving the latch 
away from the slide 41 to allow the spring bias provided by the four 
springs 41 to urge the slide 52 to the left as shown in FIG. 2. 
Accordingly the T-shaped head 50 will move with the slide 52. Thus the 
respective pins 34 are urged into one of the holes 36 in the periphery of 
the wheels 20. This is shown in greater detail in FIG. 3. In the 
embodiment shown in FIG. 3 a diameter of the wheel 20 is disposed in 
aligned relationship with the pin 34. In other words the mounting bracket 
18b and the location of the holes 62 differs from the embodiment of FIG. 
6. 
In an alternate embodiment illustrated at the bottom of FIG. 3 a solenoid 
70 is disposed at each corner of the ring 16. Brief application of power 
to each of the respective solenoids tends to force the associated pin 134 
thereof into one of the holes in the wheel 20a. In this embodiment the 
spring 141 biases the pin 134 away from the wheel 20a. In the event the 
hole in the wheel 20a is not properly aligned any movement initiated by 
infant user will ordinarily allow the pin 134 to travel into a hole in the 
wheel 20a. A spring detent may be provided to latch the pin i engagement 
with the wheel 20a. Thus, it will only be necessary to provide power to 
the solenoid 70 for a brief interval of time. 
In various embodiments of the invention the pin 34 or 134 may enter a bore 
in the wheel that is radial as shown in FIG. 3 or may be perpendicular to 
radius as shown in FIG. 6. The number of holes provided in the wheel 20 
will depend on the orientation. More specifically, with the orientation as 
shown in FIG. 6 there is clearly a greater angular sector used up by each 
bore or hole than in the structure shown in FIG. 1. 
Various alternative structures will be apparent to those skilled in the 
art. For example, the wheel 20 shown in FIG. 3 do not necessarily caster 
as in FIG. 6. In some embodiments for cup 40 may have the axis thereof 
disposed in aligned relationship with a bore in the wheel. In still other 
embodiments a curved tube maybe provided to direct the pin into the bore. 
Ordinarily the apparatus in accordance with the invention includes means 
for preventing further movement of the wheels 20 and hence the walker 10 
upon the occurrence of some predetermined event or the elapse of some time 
interval. In the preferred embodiments a transmitter 70 that includes an 
infrared transmitter receiver 72 that emits an infrared beam 74 that in 
normal operation will strike a reflector 76 and return to the transmitter 
receiver 72. This aspect of the structure is somewhat similar to the 
apparatus used to signal the arrival and departure of customers in stores. 
If the beam 74 is obstructed the receiver transmitter will energize a relay 
80 that will provide electrical power to a radio transmitter 82 and an 
audible alarm 90. The radio transmitter 82 broadcasts a signal 84 that is 
received by a receiver 86 disposed on the walker 10. This aspect is 
similar to apparatus commonly used to control garage doors. 
In operation the receiver transmitter 74 and reflector are paced in space 
relation at the top of a stairway or across a doorway to a room that a 
parent may wish to preclude an infant from entering. If the infant breaks 
the beam 74 the relay 80 triggers the alarm 90 and activates the 
transmitter 82. The signal 84 to the receiver 86 energizes the relay 60 
that releases the latch 58 causing the slide 52 to move upwardly (as shown 
in FIG. 3). This allows the respective springs 41 to urge the respective 
pins 34 into holes in the wheels 20 or 20a. Thus the respective wheels of 
the casters 18 are prevented from rotating upon movement of the walker 10 
into a zone of danger. The zone of danger is typically defined by parent 
with the apparatus for generating a light beam 74 which cooperates with 
the reflector 76 disposed at a distance from the transmitter receiver 70. 
In the event the light beam 74 is broken such as by the passage of the 
infant or the walker into the zone of danger the transmitter 82 emits a 
signal 84 to the receiver 86 disposed on the walker 10. The respective 
Bolen cables 30 extend to the respective four pins 34 that engage the 
respective four casters 18 upon passing into a zone of danger. 
In a typical application, the parent will slide or move the slide 52 back 
against the spring bias of springs 41 and move the latch or stop 58 
against the side of the slide 52 to hold the mechanism in a cocked 
position. The stop 58 cooperates with a solenoid 60 that is operated by 
the receiver 86. When the signal 84 is received the stop 58 is moved away 
from the slide 52 and the slide 52 will move in response to the spring 
bias imposed by the springs 41 to allow the pins 34 to enter the 
respective holes of the respective caster wheels 20. 
It will be understood that at the moment the stop 58 is released from the 
slide 52, the caster wheels 20 may not have a hole aligned with each of 
the respective pins 34. It will be understood by those skilled in the art, 
however, that if the infant or other user should move the walker ever so 
slightly there will be a slight rotation of the individual wheel 20 and 
this will allow the spring bias against the cable 30 to push the pins 34 
into their respective hole in the caster wheel. 
Because the typical caster wheel is disposed in eccentric relationship to 
the vertical axis about which the caster can move it will be necessary in 
some embodiments to provide a tube (not shown) to direct the cable 30 
along a path that extends generally vertically along the geometric axis 
about which the caster rotates and then extends through a an arc that has 
one end aligned with the vertical axis of the caster 18 and the other end 
aligned with a radius of the caster wheel 20. Alternatively, if the wheel 
20 is less offset, as shown in FIG. 6 the pin 34 will still engage the 
wheel 20 even though the arc shaped tube is not used. 
In the other embodiment of the invention, there is also provided the same 
receiver 86 and transmitter 70 as described before. The primary difference 
is in the use of four solenoids 70 at the respective caster wheels 20 that 
are operated by the receiver 86. Ordinarily, it will be only necessary to 
energize the solenoids for a short period of time and this is desirable to 
minimize drain on a battery provided in the apparatus. More specifically, 
a spring biased latch 92 cooperates with a stop 96 to hold the pin 134 
thereof in engagement with the wheel 20a. 
The invention has been described with reference to its illustrated 
preferred embodiment. Persons skilled in the art of such devices may upon 
exposure to the teachings herein, conceive other variations. Such 
variations are deemed to be encompassed by the disclosure, the invention 
being delimited only by the following claims.