Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FOLDABLE CART
FIELD OF THE INVENTION
This invention relates to foldable wheeled vehicles
and associated foldable receptacle, in particular, to 4-
wheeled foldable carts of flexible design permitting use both
as a walker and a shopping cart.
DESCRIPTION OF THE PRIOR ART
Numerous foldable wheeled vehicles have been pro-
posed in the past. Many early patents such as U.S. Patent
174,597 March 7, 1876 and U.S. Patent 220,214 patented Oct-
ober 7, 1879 disclose foldable baby carriages having four
wheels and a collapsible carrier.
Other more recent patents such as U.S. Patents3,194,577 and 3,337,230 disclose baby walkers which are 4-
wheeled vehicles of a foldable design including a collapsible
receptacle, in this case, the receptacle being the baby support.
Other 4-wheeled collapsible carriers include portable clothes
baskets such as the one disclosed in U.S. Patent 2,467,900
April 19, 1949, and various folding lawn carts such as the one
shown in U.S. Patent 4,222,585 issued September 16, 1980. In
the latter case, however, the folding lawn carts are rarely 4-
wheeled vehicles.
None of the foregoing provide any support for the
user except in the case of the baby walkers in which case the
user is within the sollapsible fabric receptacle. None of the
carts or carriages when folded appear to be stably self-
standing, and none is arranged to permit stacking.
SUMMARY OF THE INVENTION
In accordance with the present invention, a flexibly
designed collapsible cart is provided with an associated
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collapsible fabric receptacle~ The design is such as to be
sufficiently stable as to provide support for the user to
permit the cart to be used as a walker, to permit wide vari-
ations in load-carrying capacity, to stand stably when coll-
apsed and of a design which permits minor modification so
that a number of such carts may be stacked.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, Figure 1 is an elevational view
of a first embodiment of this invention.
Figure 2 is a rear elevational view of the cart
shown in Figure 1.
Figure 3 is a view of the cart of Figure 1 collapsed.
Figure 4 is a perspective view of the cart in Figure
1.
Figure 5 is a perspective view of a modified form
of the cart to permit stacking.
Figure 6 is an elevational view of a plurality of
carts of the type illustrated in Figure 5 in their stacked
position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As will be seen in Figures 1 and 4, the cart consists
of a frame member 1 in the form of a substantially rectangular
loop of tubular material having two side members, 2 and 3, and
two end members, 4 and 5. A second frame member 6 consists of
two legs 7 and 8 joined near their lower end by a cross-member
9 and connected to the first frame member 1 by bolts 10 and 11
which pass through the ends of legs 7 and 8 and side members 3
and 2 respectively, thus supporting the legs 7 and 8 on the
first frame member 1.
The lower end of frame member 1 is bent near its end
into a plane on which the cart is to travel. Closely adjacent
to the bend, a cross-member 12 is joined by suitable means, for
example welding, to each of the side members 2 and 3. A pair
of wheels 13 and 14 are mounted on swivels attached to the
cross-member 12. A similar pair of wheels 15 and 16 are
mounted in trunnions attached to the lower ends of legs 7 and
8 respectively.
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A collapsible strut 17 connects side member 3 of
the first frame member to leg ~ of the second frame member.
A similar collapsible strut 18 connects side member 2 to leg
8. Strut 17 comprises two arms 19 and 20 with arm 19 being
pivotally connected to side portion 3 of frame member 1, and
20 being pivotally connected to leg 7. The two arms 19 and
20 are joined at their centre point by a threaded member fix-
edly attached to arm 19, passing through arm 20, and secured
thereto by a wing nut 21. In a similar manner, strut 18 con-
sists of two arms and their associated central pivot, alsofastened by means of wing nut here designated 22.
The receptable 33 comprises a box-shaped flexible
bag of suitable fabric. One end of the bag is fastened to a
rod 23 which is joined at each of its ends to the side members
2 and 3 of the frame member 1. The other end of the bag is
joined to a rod member 24 which is joined at each of its ends
to arm members 25 and 26 respectively. The lower ends of the
arm members 25 and 26 are pivotally connected to the side
members 3 and 2 respectively.
In operation, the cart is arranged as shown in Fig-
ures 1, 2 and 4 with the frame members spaced as far apart as
permitted by the struts 17 and 18. As will be seen, the upper
end of frame member 1, that is, end member 4, which is the
handle of the cart, falls almost directly over the axes of
wheels 15 and 16, thus ensuring that downward forces on the
handle produce a very small couple for causing rotation of
the cart about the wheel axis. The centre of gravity of the
cart is well forward of the axes of wheels 15 and 16 and there-
fore produces a relatively large couple as compared to that
produced by the handle around the same axes. The handle of the
cart therefore provides substantial support for the user.
When not in use, the struts 17 and 18 can be coll-
apsed permitting wheels 16 and 14 to approach each other as
shown in Figure 3. The cart may be maintained in its collapsed
position by tightening wing nuts 21 and 22. As will be seen in
Figure 3, when in this collapsed position, the cart balances on
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wheels 13 and 14 on one side and on the end member 5 on the
other with the centre of gravity of the cart substantially
directly above a point between these two bearing points.
As shown in Figure 3, the receptacle also may be
collapsed and maintained in this position by means of a
strap 27 joined to the centre of the back of the receptacle
and fastened by means of a dome fastener 28 to the front of
the receptacle.
As will be seen in Figure 2, wheels 15 and 16 are
spaced further apart than wheels 13 and 14 and thus the wheels
are permitted to nest as shown in Figure 3.
A variation of the cart is shown in Figures 5 and 6.
It will be noted in Figures 5 and 6 that similar designations
have been used for similar components, but with an "A" design-
ation to indicate they differ from the components of the first
embodiment. Here the first frame member lA is similar in shape
to the frame member 1 of Figure 1, but the upper or handle
member is bent closer to the pivot point joining legs 7A and 8A
to the side members 2A and 3A. Struts 17A and 18A are sub-
stantially identical to struts 17 and 18 of the first embodi-
ment and are similarly pivotally connected to the side members
2A and 3A and to the legs 7A and 8A and, at their centre points,
with wing nut connectors 2lA and 22A.
The receptacle once more is formed of suitable fabric
and is supported at its front,upper edge by means of rod 24A
and a pair of arms 25A and 26A. The receptacle is larger than
that of the previous form and has an additional rod and pair
of arms 24B and 25B, 26B respectively, supporting its rear upper
edge. The receptacle is now attached to the frame with bolts
31 and 32 through grommets in the fabric of the receptacle.
Although the cart now has two sets of support arms
rather than one, the folding of the cart frame and receptacle
is the same except that the back of the receptacle has now to
be folded in as well as the front.
For the variation of Figure 5, a detent 29 is
provided on side member 3A and a similar detent 30 is provided
on side member gA. These detents are in the form of a rear-
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wardly projecting hook. As will be seen in Figure 6, the cart
of Figure 5 may ~e stacked with other carts of the same design.
To stack a cart, the frame is folded as described above in the
first embodiment and the receptacle is folded by collapsing
arms 25A, 26A and 25B, 26B in toward the frame. The upper
member 4A o the folded cart is then made to engage the detents
29 and 30 of the cart lower in the stack, thus maintaining the
completely folded cart in its stacked position.
When a user wishes to obtain a cart, he simply lifts
the handle 4A away from the detents 29 and 30 of the lower cart,
rolls the cart away from the stack, and unfolds the frame and
receptacle.
It will be seen in all embodiments that the relation-
ship between support arm angle and depth of receptacle is
important to prevent the receptacle from folding when loaded.
The design should be such that the load produces a vector force
on bar 24 which has a direction below that of the arms 25 and
26, thus causing the arms 25 and 26 to tend to rotate in an
outward direction and to maintain the receptacle fully extended.
As will be seen, the load placed in the receptacle
induces a tension in the upper edge of the receptacle, and as a
result, this upper edge may have to be reirforced with a heavier
fabric than that of the remainder of the receptacle, and
similarly, that portion of the fabric receptacle that is joined
to rods 23 and 24 may have to be reinforced to support the load
in an adequate manner.
The embodiment of Figure 5 is depicted with fixedly
supported wheels at front and back. To change to fixedly
supported wheels all round, the couple caused by a downward
force on the handle member 4 has to be increased by moving the
handle backwards with respect to the rear wheels 15 and 16 to
make it easy to lift the weight off the front wheels for
steering.
The member 9 or 9A between rear leg members 7 and 8
or 7A and 8A is important for structural stability of the cart.
Whatever the design of cart, the member is also useful, and is
designed for bracing a foot against to help lift the front
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wheels over an obstacle.
While the invention has been described in association
with a preferred embodiment and one variation, it will be
understood that, because of the flexible design, various other
minor modifications can be made without departing from the
general intent. For example, while the embodiment shown in
Figures 1 and 2 is intended as a walker and therefore struct-
urally rugged, the embodiment shown in Figures 5 and 6 may be
of lighter construction, since the mass is not required to
support the user. Also as is seen, the size of receptacle,
the method of its attachment to the frame, and the relative
position and shape of various components may change slightly
depending on the intended use. Although the embodiment of
Figure 5 is depicted with fixedly supported wheels at front ar.d
lS back, it is apparent that a cart of similar design, with double
support arms and/or stacking ability, could have pivotally
supported wheels at the front like the embodiment of Figure 1.
