Note: Descriptions are shown in the official language in which they were submitted.
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COLLAPSIBLE WHEELBARROW
Field of Invention
This invention relates to wheelbarrows. In particular, this invention relates
to
a collapsible wheelbarrow for domestic and industrial use.
Background of the Invention
Wheelbarrows are popularly used for a variety of domestic and industrial
purposes, such as for storing and transporting materials like soil and other
gardening media,
foliage, gardening supplies and construction materials, mixing and
transporting cement and
concrete, etc. A wheelbarrow is essentially a container mounted on a wheel
supporting the
front of the container, with rear legs that allow the wheelbarrow to stand
self supported and
handles for raising the legs off of the ground so that the wheelbarrow rolls
freely on the
wheel.
To accommodate the myriad uses for which they are suited and maximize
productivity during use, wheelbarrows tend to be bulky and somewhat
cumbersome. The
container portion must have the capacity to store and transport a reasonably
large load, and in
general the side walls of the container are flared for easier access to the
container bottom and
to facilitate dumping of materials. The legs are splayed to a wide stance, to
stabilize the
wheelbarrow when free standing. These features result in a large frame and
container which
is commensurately difficult to store, package and ship, and transport from one
site to another.
It would accordingly be advantageous to provide a wheelbarrow which is
collapsible, so that when not in use it can be collapsed to occupy less space
and thus be more
readily stored, packaged and transported. However, the container should be
water-tight, to
allow for popular uses such as mixing mortar, concrete, cement and the like,
which renders
the use of a collapsible container formed from rigid panels problematic.
Further, the
wheelbarrow must not lose its structural integrity or collapse inadvertently
when carrying
heavy loads such as construction materials.
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The present invention overcomes these disadvantages by providing a
collapsible wheelbarrow having a flexible container mounted on a foldable
frame. The frame
folds vertically, laterally and longitudinally, to provide a collapsed
wheelbarrow which is
considerably smaller in all three dimensions than the wheelbarrow in its
unfolded condition.
The invention accomplishes this by providing a container formed from a
water-tight, rugged and flexible fabric, to retain the versatility of a
conventional wheelbarrow
while substantially reducing the size of the container in the collapsed
condition. The
container is mounted on a frame which is hinged to allow the wheelbarrow to
collapse in two
directions, and comprises handles which are articulated to the frame and can
be folded
alongside the frame to collapse the wheelbarrow longitudinally.
The present invention thus provides collapsible wheelbarrow, comprising a
frame comprising a pair of opposed leg support members connected to a pair of
opposed
wheel support members at a pair of opposed hinges, such that the frame folds
in a vertical
direction, each leg support member comprising a leg disposed rearwardly of the
hinge and a
front support element disposed forwardly of the hinge, each wheel support
member
comprising a rear support element disposed rearwardly of the hinge and a wheel
support
element disposed forwardly of the hinge, wherein front ends of the leg support
members are
hingedly connected and front ends of the wheel support members are hingedly
connected
such that the frame folds in a lateral direction, and a container formed from
a flexible material
having front, rear and side edges, the front edge being mounted to the front
support elements
and the rear edge being mounted to the rear support elements, and first
locking means for
retaining the frame in a vertically unfolded condition and second locking
means for retaining
the frame in a laterally unfolded condition.
In a further aspect of the invention the first locking means comprises a pair
of
opposed handles, the handles being hingedly attached to the rear support
elements and
comprising rear support arms pivotable from a folded position to an unfolded
position in
which the rear support arms tension the side edges of the container against
the front support
elements.
The present invention further provides a kit of parts for assembling a
collapsible wheelbarrow, comprising a pair of opposed leg support members, a
pair of
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opposed wheel support members for connection to the opposed leg support
members to form
a frame, the wheel support members being connectable to the opposed leg
support members
at a pair of opposed hinges such that the frame folds in a vertical direction,
each leg support
member comprising a leg disposed rearwardly of the hinge and a front support
element
disposed forwardly of the hinge, each wheel support member comprising a rear
support
element disposed rearwardly of the hinge and a wheel support element disposed
forwardly of
the hinge, front ends of the leg support members being hingedly connectable
and front ends
of the wheel support members being hingedly connectable such that the frame
folds in a
lateral direction, and a container formed from a flexible material having
front, rear and side
edges, the front edge being mountable to the front support elements and the
rear edge being
mountable to the rear support elements, and first locking means for retaining
the frame in a
vertically unfolded condition and second locking means for retaining the frame
in a laterally
unfolded condition.
Brief Description of the Drawings
In drawings which illustrate by way of example only a preferred embodiment
of the invention,
Figure 1 is a side elevation of the wheelbarrow in an unfolded condition,
Figure 2 is a front end elevation of the wheelbarrow in the unfolded
condition,
Figure 3 is a side elevation of the wheelbarrow in a collapsed condition,
Figure 4 is a bottom plan view of the wheelbarrow in the collapsed condition,
Figure 5 is an exploded perspective view of the wheelbarrow,
Figure 6 is a plan view of a pattern for the container of the wheelbarrow,
Figure 7 is a partial side elevation showing a handle for the wheelbarrow in
the
unfolded condition,
Figure 8 is a partial side elevation showing the handle for the container of
the
wheelbarrow of Figure 1 in the collapsed condition,
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Figure 9 is a bottom plan view of the retainer latch,
Figure 10 is a bottom plan view of the scissor lock, and
Figure 11 is a perspective view of a lock washer limiting the unfolding motion
of the frame.
Detailed Description of the Invention
Figures 1 to 5 illustrate a preferred embodiment of the invention. The
wheelbarrow 10 comprises a container 20 mounted on a frame 30.
The container 20 is preferably formed from a flexible, water-tight fabric
which
is sufficiently sturdy to be self supporting in the unfolded condition and to
resist tearing
during ordinary use, for example a commercially available rugged plastic or
rubber
membrane or a plastic- or rubber-impregnated fabric or mesh.
The container 20 comprises a bottom panel 22, rear panel 24 and side panels
26, illustrated in Figure 6, which may be sewn, bonded or welded together in
conventional
fashion. The edges of the panels 22, 24, 26 are provided with reinforcing
flaps 22a, 24a, 26a,
respectively, which are folded over onto the panel and sewn, bonded or welded
to the panel to
form hems which rigidify the upper edges and increase resistance to tearing
and separation of
panels. It will be appreciated that the particular fabric used for the
container and the precise
configuration, mode of attachment and dimensions of the panels 22, 24, 26 are
a matter of
selection.
The container 20 is mounted on a frame 30 comprising left and right leg
support members 40 respectively hinged to left and right wheel support members
50 at an
intermediate point thereof. The support members 40, 50 are preferably formed
from
corrosion-resistant metal tubing suitable for the intended load capacity of
the wheelbarrow.
The leg support members 40 each comprise a leg 42 preferably integrally
formed with a front support element 44 which supports the front end of the
container 20
through a fabric or metal strap 38 extending between the front support
elements 42 at an
intermediate position. The top-front edge of the container 20 is affixed by
bolts, screws,
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rivets or other suitable fastening members through retaining bars 48a to
crossbar elements 48
extending laterally inward from the front support elements 44, which are
hinged together at
49. The legs 42 preferably have hooked feet 46, which provide handles to
facilitate grasping
the frame for unfolding and carrying the wheelbarrow 10.
Each wheel support member 50 comprises wheel mount element 52 preferably
integrally formed with a rear support element 54 which supports the rear end
of the container
20 as hereinafter described. The main hinges 33 connect the respective left
and right support
members 40, 50 in a scissors fashion, so that when folded the wheel support
members 50 nest
within the leg support members 40, as shown in Figure 4. This provides the
frame 30 with
the ability to fold vertically.
The wheel mount elements 52 comprise crossbar elements 58, shown in Figure
2, which are hinged together at 59. The hinge 59 operates in conjunction with
the hinge 49
to provide the frame with the ability to fold laterally. As shown in Figure 5,
the hinges 49,
59 may be formed from a constricted end of one crossbar element 48 or 58,
projecting into
the other crossbar element 48 or 58, respectively, and secured therein by a
pin or bolt so as to
be pivotable within an arc sufficient to allow the leg support members 40 and
the wheel
support members 50 to be folded toward one another as shown in Figure 4.
The wheel 12 is mounted on an axle 14 extending through brackets 56 which
depend from the wheel support members 50. Typically a suitable position would
be recessed
from the crossbar elements 58, which allows the wheelbarrow 10 to be tipped
forward
supported by the crossbar elements 58 (ie. off of the wheel 12) to facilitate
dumping a load
from the front of the wheelbarrow 10. The axle is slidably received in
brackets 56, which
allows the brackets 56 to slide along the axle 14 as the frame is folded and
unfolded in the
lateral direction.
The rear support elements 54 of the wheel support members 50 are
articulatively connected to handles 60 at hinge arms 62. The ends of the hinge
arms 62 are
hingedly connected to the handles 60 and to the rear support elements 54 so
that the hinged
ends 64 of the handles 60 butt against the hinged ends 56 of the rear support
elements 54
when the handles 60 are opened to the unfolded position shown in Figures 1 and
7.
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Preferably the hinged ends 64 of the handles 60 are beveled and the hinged
ends 56 of the rear support elements 54 are beveled complimentary to the
hinged ends 64 of
the handles 60, as shown in Figures 7 and 8, so that the application of
downward pressure to
the handles in the unfolded position firmly engages and aligns the hinged ends
64 of the
handles 60 with the hinged ends 56 of the rear support elements 54. As the
handle 60 is
unfolded a bolt 66 affixed to the hinge arm 62 by bracket 65 swings into
position over the
joint between the hinged ends 64 of the handles 60 and the hinged ends 56 of
the rear support
elements 54. Rotation of the knob 68 drives the bolt 66 through the hinged end
of the handle
60 and into a nut 67 welded to the interior of the hinged end of the rear
support element 54
(shown in phantom in Figures 7 and 8) to lock the hinge arm 62 in the unfolded
position
shown in Figure 7 when the wheelbarrow 10 is in use. This also locks the frame
30 in the
vertically unfolded condition, as is described below.
Rear support arms 72 are respectively connected to the bolts or pins which
secure the ends of the hinge arms 62. The free ends 74 of the rear support
arms 72 project
upwardly in the unfolded position to support the top-rear corners of the
container 20, to which
the free ends 74 of the rear support arms 72 are affixed by bolts, rivets or
any other suitable
fastening member.
The frame 30 is retained in the unfolded condition shown in Figures 1 and 2
by a scissor lock assembly 80, shown in Figures 4 and 10, which comprises a
pair of bars 82
connected at an intermediate point by hinge 84 and each bar 82 having one end
pivotally
connected to one wheel support member 50 near the rear end of the frame 30.
Each bar 82
has a slot 86 positioned to engage over a pin 88 projecting from the other bar
82, best seen in
Figure 10. When the frame 30 is in the collapsed condition (scissor hinge in
position "A"
shown in phantom lines in Figure 10) the bars 82 are oriented at an acute
angle relative to one
another. As the frame 30 is unfolded the bars assume an obtuse angle relative
to one another
(scissor hinge in position "B" shown in phantom lines in Figure 10), and to
lock the frame 30
into the unfolded condition (shown in solid lines in Figure 10) the bars 82
are forced into
alignment with the pins 88 engaged into the slots 86. This stabilizes the
spacing between the
wheel support members 50, and thus between the leg support members 40 which
are hinged
thereto, to retain the frame 30 in the unfolded position. The scissor lock
assembly 80 also
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provides considerable leverage as the frame 30 approaches the unfolded
condition, which
tensions the top edges of the container 20 for enhanced rigidity and greater
stability.
The frame 30 is retained in the collapsed condition by a retainer bar 90,
shown
in Figures 4 and 9, which may be pivotally connected to one wheel support
member 50 at the
point of attachment of one side of the scissor lock assembly 80. As shown in
Figure 9, the
retaining bar 90 is provided near its free end with a slot 92 which engages
over a pin 94
projecting from the hinge of the opposite bar 82 in the scissor lock assembly
80, to prevent
the frame 30 from unfolding inadvertently from the collapsed condition.
In operation, with the frame 30 in the collapsed condition shown in Figures 3
and 4, the retaining bar 90 is manually pivoted away from the pin to release
the frame 30 for
unfolding. Grasping the feet 46, the user pulls the leg support members 40
apart to unfold the
frame 30 laterally, grasping and pulling the scissor lock assembly 80 into the
unfolded
position (bars 82 aligned) shown in solid lines in Figure 10, locking the
frame 30 into the
laterally unfolded condition. This causes the rear support arms 72 to tension
the top-rear edge
of the container 20 and unfolds the hinges 49 and 59. The top-front edge of
the container 20
is retained in a tensioned condition by the retainer bars 48a affixed to
crossbars 48.
The user unfolds the handles 60, swings the latch bar 66 into the locked
position shown in Figure 7 and tightens each knob 68 to drive the bolts 66
through the ends
of the handles 60 into the nuts 67, to lock the handles 60 in the unfolded
position. Unfolding
the handles 60 causes the rear support arms 72 to swing upright, drawing the
top-rear corners
of the container 20 rearwardly and, by tensioning the top-side edges of the
container 20,
drawing the front support elements 44 away from the wheel support elements 52.
The frame
30 thus unfolds vertically in a scissors fashion, and is retained in the
vertically unfolded
condition so long as the handles 60 remain locked in the unfolded condition,
by the tension of
the top-side edges of the container 20 between the rear support arms 72 and
the crossbars 48.
The reinforcing hems along the top edges of the container 20 thus serve as
tensioning
elements to retain the frame 30 in the vertically unfolded condition.
The frame 30 is prevented from overextending into the vertically unfolded
condition by lock washers 96, shown in Figure 11, disposed between the leg
support
members 40 and the wheel support members 50. As the frame 30 reaches the
vertically
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unfolded condition the stops 96a on the lock washers 96 come into contact with
one another
and arrest further unfolding of the frame 30. This maintains tension on the
top-side edges of
the container 20.
The wheelbarrow 10 is now ready for use. The top-side and top-rear edges of
the container 20 are maintained tensioned by the frame 30, imparting
sufficient rigidity to the
container 20 to retain the desired shape.
To collapse the wheelbarrow 10 of the invention, the thumbscrews 68 are
loosened and, the latch bars 66 are pivoted out of the locked position and the
handles 60 are
folded over the frame 30, which retracts the rear support arms 72 and allows
the front support
element 44 to collapse toward the wheel mount element 52 in a scissors
fashion. The user
pushes the hinge 84 of the scissor lock assembly 80 forwardly, causing the
slots 86 to
disengage from the pins 88 and the bars 82 to fold toward one another, which
collapses the
frame 30 laterally. The retainer bar 90 is pivoted to latch onto the pin 88,
and the collapsed
wheelbarrow 10 is ready for storage or transport.
A preferred embodiment of the invention having been thus described by way
of example only, it will be apparent to those skilled in the art that certain
modifications and
adaptations may be made without departing from the scope of the invention, as
set out in the
appended claims.
