Note: Descriptions are shown in the official language in which they were submitted.
CA 02638613 2008-08-06
CARGO CART FOR WHEELED MOBILITY DEVICE
FIELD OF THE INVENTION
This invention relates to carts propelled and controlled by a user, and more
specifically to
cargo carts that can be attached to a mobility device.
BACKGROUND OF THE INVENTION
Many people who have balance problems or weak muscles use some type of
mobility
device, such as an electric scooter or walker frame. These mobility devices
typically
require the user to use both hands to operate the device. The user steers the
mobility
device and either pushes the device with both hands or uses the hands to
operate
mechanical throttle and brake controls.
Because the user does not have a hand free for carrying any objects, such
mobility aids
frequently have some article carrier attached to it. Scooters often have a
bicycle type
basket mounted between the handlebars. Walker frames may have a tray, basket,
or
pouch attached to the frame. Users of walker frames with seats often place
articles on the
seat for transport.
Such article carrying coritainers are limited in size and lend themselves to
transport of
articles of only certain shapes and sizes. The carrying containers are
typically attached to
the upper part of the mobility device such that carrying heavy items can make
the
mobility device easier to overtum and harder to steer. Articles placed on a
seat often fall
off.
Thus, there is a need for a cart that users of mobility devices can use to
safely carry larger
and more awkwardly shaped articles than can be carried in conventional
baskets, trays, or
pouches.
Various attempts to create carts for use with wheelchairs have been made. One
of the
more practical-appearing examples is US Patent 4,484,755 of Houston. One
embodiment
of Houston's cart is included in the drawings herein as Figure 1, labeled
"Prior Art."
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Houston's cart 200 is supported by four wheels 210 and is attached to the
front of a
wheelchair 300 or walker frame (not shown). The axles of all four wheels 210
of cart 200
and the front pair of wheels 310 of wheelchair 300 are offset from the
attachment points
of wheels 210,310 such that all three pairs of wheels 210,310 are freely
pivoting. This
arrangement will likely result in unpredictable steering of the cart and
wheelchair
combination.
Houston does not describe the detailed means by which the user of wheelchair
300 steers
cart 200. Figure 1 shows that the cart and wheelchair combination includes
three pairs of
pivoting casters 210, 310 in series. The user of wheelchair 300 may need to
use
"opposite" steering, such as used by the driver of an auto with attached
trailer to back up.
Actually, the steering is likely to be far more unpredictable than simple
opposite steering
and the wheelchair/cart combination may tend to lock up during a complicated
maneuver,
such as a three-point turn in a grocery store aisle.
If Houston's cart 200 were attached to a walker frame with pivoting front
wheels, the
situation would be the same. Either the cart would swing unpredictably in
response to
steering of the walker, or the user would need to apply opposite steering and
initially
move in the direction opposite the turn.
Houston also discloses an embodiment of the cart attached to a walker frame
without
wheels (not shown). It appears the user of the walker would have to lift the
walker and
use the elevated walker frame to steer the Houston cart. This would
potentially require
more muscle power and agility than a typical user of a mobility aid device
has, as well as
putting the user off-balance with each change of direction.
The Houston cart 200 of Fig. I elevates the basket portion well above the
castered
chassis. The Houston cart 200 clearly has a very high center of gravity; when
loaded with
articles it could be dangerously top heavy.
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Other cargo-carrying carts for use in combination with wheelchairs have been
patented.
Most of them would not be feasible to use with a walker frame or scooter. None
appear to
be capable of being steered safely and intuitively by a person using a walker
frame.
Thus, there is a need for a safe, convenient cart that can be attached to a
mobility aid
device, including an electric scooter, a wheelchair, or a walking frame. There
is a need
for a cart that can be propelled and steered easily by a fragile or even
easily-confused
person using a mobility device. There is a need for a cart that has a low
center of gravity
whether empty or heavily loaded and that will not tip. There is a need for a
cart that can
securely carry a variety of large or oddly-shaped articles. There is a need
for a cargo cart
that can be easily detached from the mobility device when not needed, that can
be stored
conveniently, and that can even be used independently of the mobility device.
SUMMARY OF THE INVENTION
The present invention is a cargo cart that can be attached to a mobility
device, in
particular a walker frame with wheels, often simply called "a walker.". The
cart can be
attached and detached from the walker by the user, using one hand and without
bending
over. When detached from the walker, the cart can be used as a conventional
hand truck
or folded for storage.
The cart includes a cargo platform that is supported close to the floor by a
pair of freely
swiveling casters in front and a pair of non-swiveling wheels in back. A
handle extends
upwardly from the back end of the cart.
The back end of the cart can be attached to a walker so that the walker
propels and
controls the movement of the cart. The attachment means is adapted to support
the back
wheels of the cart slightly above the floor so that they do not interfere with
the steering of
the cart supported on the casters.
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The user pushes and steers the walker in the accustomed manner. This movement
and
steering is transferred through the attachment to the cart so as to steer the
cart in the same
direction as the walker.
When the cart is not attached to a walker, it may be used as a hand truck,
such as by
pulling the cart by the handle. Thus, the cart can be used by others in the
household of the
user of the walker frame for various tasks. In this mode of use, the cart
steers better if it is
pulled so that the non-swiveling wheels precede the casters.
The cargo platform may be adapted so that it can accept many shapes of
articles. For
example, the platform is preferably surrounded by a rail to retain small
articles. The rail
preferably includes slots or protrusions to aid in holding items that are
wider than the
platform. Specialized article holders may be added, such as an optional tall
basket for
holding laundry or an insert with deep wells to hold pitchers and glasses of
beverage.
The handle of the cart is adapted for folding flat for storage of the cart
under a bed or
hanging on a wall. The optional tall basket is adapted for folding flat along
with the
handle.
The features and advantages of the invention will be readily understood when
the detailed
description thereof is read in conjunction with the drawings wherein like
reference
numerals refer to like parts throughout.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a prior art shopping cart and wheelchair combination from the
patent of
Houston.
Figure 2 is a left front perspective view of the cart of the present
invention.
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Figure 3 is a front perspective view of the cart of Figure 2 attached to a
conventional
mobility device.
Figure 4 is a left side elevation view of the cart and mobility device
combination of
Figure 3, the right side being a mirror image.
Figure 5 is a left front perspective view of a preferred embodiment of
attachment means
for the cart of Figure 2.
Figure 6 is a left front perspective view of the attachment means of Figure 5
mounted on
an alternative conventional wheeled walker.
Figure 7 is a front exploded perspective view of an alternative preferred
embodiment of
attachment means for the cart of Figure 2, in combination with an alternative
conventional wheeled walker.
Figure 8 is a left front perspective view of an alternative embodiment of the
cart of the
present invention, including a tall basket for holding cargo.
Figure 9 is a left front perspective view of the cart of Figure 8, shown in a
folded
position.
Figure 10 is a left front perspective view of the cart and walker frame
combination of
Figure 3, showing a conventional folding chair carried as cargo.
DETAILED DESCRIPTION OF THE INVENTION
Figure 2 is a left front perspective view of the cart 10 of the present
invention. Figure 3 is
a front perspective view of cart 10 of Figure 2 attached to a conventional
mobility device
100 such as a walker frame 101, such as two-wheeled walker IOIA. Figure 4 is a
left side
elevation view of cart 10 and walker l OlA combination of Figure 3.
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Cart 10 generally includes a first end 14 defining a first direction of
travel, a second end
16 defining a second direction of travel, cargo portion 20 between first end
14 and second
end 16, wheels 30, attachment means 40 for attaching cart 10 to walker 101,
and a handle
50 attached to first end 14.
First end 14 and second end 16 define a longitudinal axis x of the cart 10
stretching
between them. Cart 10 has a first and a second direction of travel, as shown
in figure 4.
Cargo portion 20 includes fraine 22 with peripheral rails 24 and cargo support
area 28
enclosed within rails 24. Frame 22 is generally rectangular and includes rails
24 on all
four edges. Rails 24 add strength to frame 22 and prevent cargo from rolling
or sliding
off of cargo support 24.
Wheels 30 are attached to frame 22 of cargo portion 20. Wheels 30 typically
include a
pair of non-pivoting wheels 34 attached to opposing sides of frame 22 near
first end 14
such that the axis of rotation of each whee134 is perpendicular to
longitudinal axis X.
Wheels 30 further include one or more casters 32 attached to frame 22 near
second end
16. Caster 32 is a conventional pivoting roller including an offset bracket
33A and rolling
member 33B. Offset bracket 33A is free to pivot at least 180 about a vertical
axis.
Rolling member 33B is rotatably mounted in offset bracket 33A with a
horizontal axis of
rotation. Because the pivot axis and rotation axis of caster 32 are offset,
rolling member
33B has many degrees of freedom for traveling upon travel surface 150.
Preferably, one caster 32 is attached to each of the opposing sides of frame
22 to which a
non-pivoting whee134 is attached. If cart 10 has four wheels 30 attached at
four corners
of a generally rectangular frame 22, the carrying capacity of cart 10 is
maximized and
cart 10 will not easily tip over when loaded.
Handle 50 is attached to frame 22 near first end 14. Handle extends upwardly
from frame
22 to a height that is convenient for a user to grasp. Handle 50 may be a U-
shaped frame
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as depicted in the drawings, a single upright shaft, or any other convenient
arrangement.
Handle 50 is preferably narrow in side profile so as to not interfere with
walker 101 when
cart 10 is attached.
The preferred embodiment of handle 50, attached near first end 14, as shown in
the
drawings, provides a secondary benefit of acting as a safety screen to help
stabilize
loaded cargo and prevent items being carried on cart 10 from falling through
the frame of
walker 101 and striking or tripping a user.
Handle 50 is used to pull and steer cart 10, preferably in the first direction
of travel, when
cart 10 is unattached to walker frame 101. Preferably, handle 50 can be
shortened for
storage of cart 10 when not in use. Handle 50 may be adapted to fold flat over
cargo
portion 20, telescope downward to a low height, or even be removed from frame
22.
Figures 3 and 4 illustrate cart 10 attached to a walker 101A that includes
left side 120,
right side 122, and center section 124 connecting right and left sides
120,122.
Cart 10 is selectively attachable to any walker 101 with cooperative
attachment means
40. Attachment means 40 typically includes two cooperating components: cart
attachment means, which is typically an integral part of frame 22, such as
hook means
such as hooks 42, and walker attachment means 43.
Walker attachment means 43 typically includes a horizontal roll leader 44 that
engages
with hooks 42. As seen in figure 3, center section 124 of walker 101 A
includes a lower
crossbar 126. Lower crossbar 126 is in the desired range of 5 % to 5 % inches
above
travel surface 150, so crossbar 126 is well adapted for use as roll leader 44.
Cart 10 is attached to walker 101 A by positioning hooks 42 close to roll
leader 44 and
pulling upward on handle 50, preferably with no cargo loaded in cart 10.
Handle 50 is
manipulated to engage hooks 42 with roll leader 44. This operation may be
performed
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with only one hand, so that one hand can remain on walker IOIA for support or
balance.
The user does not need to bend over to see or manipulate small fittings.
As best seen in figure 4, when hooks 42 are engaged with roll leader 44, first
end 14 of
cart 10 is attached to walker frame IOIA and non-pivoting wheels 34 are
supported about
0.5 inch above travel surface 150. Supporting non-pivoting wheels 34 above
travel
surface 150 simplifies steering of the combination of cart 10 with walker 101,
as will be
explained below.
To use cart 10 with a walker 101 that does not have an appropriate existing
feature to use
as roll leader 44, an adaptor bracket 47 is removably mounted upon walker 101
to adapt it
for attachment to hooks 42.
Figures 6 and 7 depict alternative walker frames 101. Figure 6 shows a walker
frame
101 B with two front wheels 104 and two rear wheels 105.
Walker frame 101 A of figures 3, 4, and 10 and walker frame 101 B of figure 6
are
controlled by gripping control means 110 of walker frame 101, such as the
uppermost
portions of left and right sides 120,122 of walker frame l OlA or walker frame
101B.
Walker frame 101 C of figure 7 is controlled by handlebars 110B.
The user propels walker frame 101 by pushing or pulling control means 110 and
steers by
applying differential pressure to left and right control means 110. The
differential
pressure causes the pair of front wheels 104 to turn toward the desired
direction. The rear
wheels 105 of walker frame l O1B respond, as do casters 32 of cart 10. Both
the
propulsion and the steering are directly transferred from control means 110
through roll
leader 44 to cart 10.
If non-pivoting wheels 34 were left in contact with travel surface 150 when
cart 10 is
attached to walker 101, the multiple pairs of wheels would confuse the
direction of
steering. In some cases, the user might need to steer walker 101 in the
opposite direction
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from the direction desired in order to steer cart 10 in the direction desired.
In some cases,
non-pivoting wheels 34 might get into an orientation that would require
forward-and-
backward shuffling of walker 101 to get straightened out, or might require
excessive
force from the user to overcome.
Because the cargo cart 10 of the present invention supports non-pivoting
wheels 34 above
travel surface 150 when attached to walker 101, casters 32 follow front wheels
104 of
walker frame 101 easily and predictably.
Figure 5 is a front perspective view of an alternative preferred embodiment of
walker
attachment means 43, adapter bracket 47 such as drop bracket 46. Drop bracket
46 is for
adapting walker 101 B to cooperate with hooks 42. Drop bracket 46 includes
roll leader
44 and mount means to mount drop bracket 46 on walker 101 B, such as plurality
of
hooks 49. Figure 6 is a front perspective view of drop bracket 46 of Figure 5
mounted on
walker 101 B.
Roll leader 44 is a preferred height above travel surface 150. Hooks 42 can
then be
dropped onto roll leader 44 as described above.
Figure 7 is a front perspective, exploded view of an alternative preferred
embodiment of
adapter bracket 47, such as crosstie 48, for adapting conventional walker 101C
for
attachment to cart 10. Crosstie 48 includes roll leader 44 and mounting means
such as
clamps 45. Clamps 45 are used to mount crosstie 48 on walker 101C at a desired
height
for engaging with hooks 42.
It can be seen that many designs of walker 101 can be adapted for use with
cart 10 by
mounting an appropriate adaptor bracket 47. Preferred features of a
appropriate walker
adaptor bracket 47 are that it provide an attachment point such as roll leader
44 that will
support non-pivoting wheels 34 at the preferred height when attached, that
adaptor
bracket 47 is easy to mount on walker 101, that cart 10 is easy to attach to
adaptor
bracket 47 with one hand and without bending, and that adaptor bracket 47 does
not
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impede the normal use of walker 101, such that it will not be necessary to
remove adaptor
bracket 47 after every use of cart 10.
Cooperative attachment means 40 has been described and illustrated herein as
comprising a
pair of hooks 42 for mounting upon a horizontal crossbar 126 or roll leader
44. It will be
apparent that many forms of mechanical attachment as are well known are
feasible for use
as cooperative attachment means 40.
For example, hooks 42 may alternatively comprise a single half tube attached
to first end 14
and opening downwardly, that engages roll leader 44.
Roll leader 44 may include centering means, such as protrusions 49 on roll
leader 44, as
shown in figure 3. Figure 3 shows cart 10 attached to a walker 101 A that has
an appropriate
existing feature (crossbar 126) that functions as roll leader 44. Protrusions
49 are preferably
thick flexible rings that can be mounted on roll leader 44 or may be simply
bands of friction
tape wrapped around roll leader 44.
Cargo cart 10, as shown in Figures 2, 3, and 4, includes exemplary adaptations
for
supporting large cargo such as features 26, various recesses or protrusions of
rails 24.
Features 26 may be used for retaining a variety of cargoes, and may also be
specially
adapted for certain frequently carried items. Figure 10 shows cart 10
supporting a folding
chair 400. Although folding chair 400 is wider than cargo support 28, features
26 hold the
frame of folding chair 400 securely.
Other adaptations for retaining cargo are also possible. Figures 8 and 9 show
cargo cart
10 with a tall basket 29, such as could hold laundry or long-handled household
cleaning
tools. Basket 29 folds flat for storage, as seen in Figure 9. An alternative
preferred
embodiment, not shown, includes a closeable removable case adapted to fit
snugly within
rails 24.
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An alternative embodiment, envisioned but not illustrated, has handle 50
attached to
second end 16 of cart 10. This embodiment would have the potential advantage
of
making cart 10 easier to use as a pushed handcart in the unattached mode,
instead of a
pulled cart. This embodiment would have the potential disadvantage of limiting
the size
of cargo able to be carried by cart 10.
Although particular embodiments of the invention have been illustrated and
described,
various changes may be made in the form, composition, construction, and
arrangement of
the parts herein without sacrificing any of its advantages. Therefore, it is
to be understood
that all matter herein is to be interpreted as illustrative and not in any
limiting sense, and it is
intended to cover in the appended claims such modifications as come within the
true spirit
and scope of the invention.
For example, the invention has been mainly described and illustrated herein as
being for
attachment to a wheeled walker 101. Cart 10 is easily adapted for use with
other sorts of
mobility device, such as wheelchairs or electric scooters.
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