Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02324122 2000-10-24
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Title: WHEELBARROW CONVERSION RIT
TECHNICAL FIELD
This invention relates generally to wheelbarrows and
more particularly to a kit for converting a conventional
wheelbarrow into a three-wheeled wheelbarrow.
HACRGROUND OF THE INVENTION
It is likely that one of the earliest machines
developed by humans was similar to the modern day
conventional wheelbarrow. It represents the natural
combination of two earlier fundamental inventions, the
wheel and the lever, and a means for retaining cargo. The
basic form of the conventional wheelbarrow has probably
remained essentially unchanged for centuries. It includes
a pair of spaced beams joined at one end by a bracket and
diverging toward handles formed at the opposite ends. An
axle is mounted to each of the beams near the bracket, and
a wheel extending partially between the beams is mounted
for rotation on the axle. A pan or cargo container is
mounted atop the beams, and a rear leg extends downward
from each beam. The longevity of this design is strong
evidence of its considerable utility and durability.
Even so, the design has one deficiency which becomes
more apparent as the load carried in the pan is increased.
Because the pan is mounted on top of the beams, the center
of gravity of a loaded wheelbarrow is relatively high and
tends to rise as the weight of the load in the pan is
increased. Moreover, when the handles are raised to
elevate the rear legs, the center of gravity is raised
even higher. This, coupled with the use of a single wheel
to support the forward end of the frame, may result in a
relatively unstable vehicle which is difficult to maneuver
and easily overturned. Further, merely moving a
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0 wheelbarrow requires that both rear legs be elevated from
the ground with the rear handles, so a small person may
have difficulty in even moving a heavily loaded
wheelbarrow.
Prior art shows it is well known to mount rear wheels
to the legs of a wheelbarrow to convert it into a three
wheeled cart. However, most such designs appear to be
unnecessarily complicated and expensive so they have not
achieved much success in the marketplace. Moreover, none
of them appear to significantly.improve the stability of
a wheelbarrow when it is heavily loaded.
Accordingly, it is an object of this invention to
provide for a kit for converting a conventional
wheelbarrow into a three-wheeled wheelbarrow which is
significantly more stable when heavily loaded than
previously known designs.
It is another object of this invention to provide for
such a conversion kit which is relatively simple and
inexpensive and which does not require modification of the
original wheelbarrow structure for installation.
It is a further object of this invention to provide
for such a three-wheeled wheelbarrow which is
significantly easier to move and maneuver than is a
conventional wheelbarrow.
SUMMARY OF THE INVENTION
This invention can be broadly summarized as providing
for a kit for converting a wheelbarrow into a three-
wheeled wheelbarrow. The wheelbarrow itself is of
conventional design, having a pan for containing cargo, at
least one beam for supporting the pan and a rear leg
extending downward from the beam. The kit includes an
elongated axle, at least one wheel which can be mounted
for rotation on the axle, and a clamp assembly including
at least one U-bolt for removably mounting the axle on the
rear leg.
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0 In accordance with a more detailed aspect of the
invention, the kit includes a pair of wheels mounted for
rotation on opposing ends of the axle and a pair of clamp
assemblies, each including at least two U-bolts and a
plate mountable on the U-bolts. The kit may also include
a pair of sleeves removably mountable on the axle for
stabilizing the wheelbarrow and protecting the ends of the
axle when the rear wheels have been removed.
The invention can also be broadly summarized as
providing for an improved wheelbarrow including a pan, at
l0 least one elongated beam for supporting the pan, at least
one front wheel assembly mounted on the beam, at least one
rear leg extending downward from the beam, an elongated
axle, at least one wheel removably mountable on the axle
and a clamp assembly including at least one U-bolt for
removably mounting the axle on the rear leg.
According to a yet more detailed aspect of the
invention, the improved wheelbarrow includes a pair of
beams for supporting the pan, a front wheel assembly
mounted for rotation on each of the beams, a rear leg
extending downward from each beam, an elongated axle with
wheels mounted on the ends of the axle, and a pair of
clamp assemblies for removably mounting the axle to the
rear legs. Each such assembly includes at least two U-
bolts and a plate slidably mountable on the U-bolts.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a top, front and right side perspective
view of a conventional wheelbarrow on which a conversion
kit constructed in accordance with the teachings of the
present invention has been installed.
Figure 2 is an exploded top, front and right view o'f
a portion of the wheelbarrow of Figure 1 in the vicinity
of the right rear leg.
Figure 3 is a sectional view taken at 3-3 of Figure
2.
Figure 4 is a sectional view taken at 4-4 Figure 2.
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0 Figure 5 is a top, right and front perspective view
showing a sleeve accessory.
DETAILED DESCRIPTION OF THE PREFERRED EMHODIMENTB
The novel features believed to be characteristic of
this invention are set forth in the appended claims. The
invention itself, however, may be best understood and its
various objects and advantages best appreciated by
reference to the detailed description below in connection
with the accompanying drawings.
In Figures 1 through 4 of those drawings, an improved
wheelbarrow including a conversion kit constructed in
accordance with the teachings of the present invention is
illustrated and generally designated by the number 10.
The frame of the wheelbarrow itself includes right beam 12
and left beam 14 which are spaced apart and joined at
their forward ends 16 and 18, respectively, by nose
bracket 20. The beams diverge aft of the nose bracket and
their aft ends are formed into handles 22 and 24 (not
shown). Front wheel 30 is mounted for rotation on axle 32
and the axle is fixed to the underside of beams 12 and 14
by axle brackets 34 and 36 (not shown), respectively. Pan
40 is fastened to the top of the beams by a plurality of
bolts (not shown). In its conventional form the
wheelbarrow is supported in the rear by right leg 50 and
left leg 52 which are preferably formed of steel channel
stock and bolted to the underside of beams 12 and 14,
respectively.
A particularly significant aspect of this invention
is conversion kit 60, details of which are shown in
Figures 2 through 4. The kit includes axle 62 which is
preferably formed from 5/8 in. diameter steel stock. It
also includes right wheel 63 and left wheel 64 which are
mounted for rotation on right and left ends 66 and 68 (not
shown), respectively, of the axle. Inner and outer
washers 70 and 72 are positioned on the axle adjacent to
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0 wheel 64 as shown, and the wheel is removably retained on
the axle by linchpin 74 which is inserted in hole 76
drilled in the axle near end 66. The axle is removably
joined to horizontal portion 80 of right leg 50 by clamp
assembly 82. The clamp assembly includes U-bolts 84 and
5 86, support block 87 and nut plate 88. Referring to
Figure 4 it can be seen that the U-bolts are pbsitioned
over the axle and extend upward on either side of
horizontal portion 80 of the leg. Support block 87 is
inserted between flanges 100 and 102 and extends downward
slightly below the tops of the flanges. Four
appropriately spaced holes 90, 92, 94 and 96 are formed in
the nut plate, permitting it to be slidably mountable on
the U-bolts. Lock nuts, such as nut 98, are positioned on
the threaded ends of the U-bolts and tightened so as to
firmly clamp the axle against the support block.
Identical clamp assembly 120 is used to fasten the axle to
left leg 52 and an identical set of components is used to
removably mount left wheel 64 to left hand end 68 of the
axle.
In order to install the conversion kit it is most
convenient to begin by inverting the wheelbarrow. Next,
the spacers, washers, and wheels should be installed on
the axle and the linchpins should be inserted in the axle
ends. Then the support block should be positioned in the
leg channels of the horizontal portions of legs 50 and 52.
Next, the axle and wheel assembly should be placed on the
support blocks and aligned laterally. Finally, while the
axle is held in position on the legs, the clamp assemblies
should be installed and tightened to fix the axle in
place.
The improved wheelbarrow offers the user a number of
options for moving and maneuvering it not available with
a conventional wheelbarrow. Depending upon the weight of
the load in the pan and the strength and skill of the
operator, the wheelbarrow may be moved on the front wheel.
only, the rear wheels only or all three wheels. When it
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0 is lightly loaded, the wheelbarrow may be moved in the
conventional way by simply lifting the rear handles
sufficiently that the rear wheels are elevated from the
ground and then moving the handles forward or laterally as
desired.
The advantages of the present invention are
particularly apparent, however, when the pan is heavily
loaded. In that case the wheelbarrow can be moved by
simply applying forward force to the handles and allowing
the load to be carried by all three wheels. Maneuvering
l0 can be accomplished by applying sufficient downward force
to the handles to elevate the front wheel and then
swivelling the forward end in the desired direction. Use
of the rear wheels in that manner provides a significant
increase in the stability of the wheelbarrow. First, the
widely spaced rear wheels remain in contact with the
ground, thereby providing significantly wider spaced rear
points of contact as compared to the original legs.
Under some circumstances, such as when the
wheelbarrow is operated on a surface having a significant
slope, it may be desirable to temporarily remove the rear
wheels. That can be accomplished by removing the entire
conversion kit from the wheelbarrow or by simply removing
only the rear wheels. In the latter case, however, the
increased lateral stability provided by the wheels will be
lost and the exposed ends of the axles may be
inadvertently damaged. These two problems may be solved
by use of sleeve 130. The sleeve, which is cylindrical in
shape and preferably made of hard rubber, has an internal
diameter "d" which is sized to permit the sleeve to be
slidably positioned on axle 62 but to fit tight enough
that the sleeve will not turn easily on the axle. The
length "1" of the sleeve is sized so that when the sleeve
is positioned on the axle one end will abut nut plate 88
and the other will be essentially flush with the end of
the axle. If the rear wheels are to be removed and axle
62 left in place on the rear legs, then a pair of sleeves
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0 130 should be installed on the axle ih place of the
wheels. As can be seen, the sleeves will provide
protection for the axle ends and also will provide rear
points of contact which will not roll and which will offer
the same increased lateral stability as wheels 63 and 64.
Thus, it can be seen that the present invention
provides for a wheelbarrow conversion kit and an improved
wheelbarrow which incorporate many novel features and
offer significant advantages over the prior art. Although
only one embodiment of this invention has been illustrated
and described, it is to be understood that obvious
modifications can be from it without departing from the
true scope and spirit of the invention.
