Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MAGNETIC ATTACHMENT OF BEDKNIFE IN A REEL MOWER ASSEMBLY
This invention generally relates to improved mower reel units and mowing
devices
incorporating such units. More specifically, it relates to an alternative
method of attaching
the blade to the blade support assembly in such a mower reel unit which would
allow for
improved safety and usability features.
1o BACKGROUND
Reel mowers and mower units using reel mowing assemblies are generally known
in the art.
For example, U.S. Patent Nos. 5,291,724, 5,477,666 and 6,318,059 demonstrate
some ofthe
work or innovation in the field. While those particular patents deal with a
mower reel with
axially offset Chevron blade apexes, they demonstrate the relevant generic
parts of a reel
mower assembly. Figure 1 attached hereto demonstrates one type of a reel mower
assembly
as is known in the prior art. That particular unit shows an engine and a frame
and two
wheels mounted thereon, such that that particular unit appears to be one that
would be moved
by hand by an operator. However, the reel assembly on the front thereof is
similar to those
2o used in larger reel mowers which would potentially include multiple reel
assemblies.
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Figure 2 demonstrates from a side view the operative parts or construction of
a prior art reel
mower assembly. Finally, and again for reference purposes, Figure 3 is an
exploded view of
the mower reel assembly of U.S. Patent No. 6,31$,059, which will be used
herein to
demonstrate the new improvements of the present invention.
Refernng to prior art Figures 1-3, the bed bar (42) is the support structure
for the mower
blade (39) which holds the mower blade (39) in position in the relating reel
and the reel
assembly of a rotary reel mower unit. The method of attachment of this blade
(39) to the bed
bar (42) has in all prior art situations been by way of a plurality of screws.
Specifically, in
Figure 3 thirteen screw holes are shown in the blade (39) and support bar (42)
through which
screws are threaded to hold the blade (39) in place.
There are numerous problems or disadvantages of the bolting or screwing into
position of the
blade (39) which it is the intention of the present invention to endeavor to
address. One of
the problems and the major scenario which it is desired to alter with the
present invention is
the amount of labor required to change the blades. For example, a reel mower
assembly such
as is used by a golf course or the like may contain eight or 10 individual
mowing reel heads
and, as such, to change eight or 10 separate blades would result in the need
to remove at least
eight sets of screws to change the blades. In most cases, the screws are not
easily accessible
2o and the reel assembly has to, to some extent, be disassembled in order to
change the blades.
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The amount of labor required to change a set of blades in this scenario is
significant, which
results not only in high labor costs but also significant equipment downtime,
as the change-
over of a set of blades is accomplished.
A second disadvantage to a firmly bolted blade such as that shown in prior art
Figures 1 to 3
is that by virtue of the fixed position of the blade with the plurality of
screws holding it in
place there is little to no ability for the blade to move upon the exertion of
abnormal forces
thereon. For example, if the reel assembly should in some unanticipated
fashion pass over a
rock or hit some other obstruction, the blade cannot move and this could
potentially end up
1 o in a bending of the blade and/or the reel assembly. If the blade and more
particularly the reel
are bent in any fashion, the repair work required on the reel head as a whole
is substantial.
As such, it would be desirable to come up with some type of a bed blade
assembly that would
in some fashion allow for these abnormalities and potentially minimize reel
damage.
1s SUMMARY OF THE INVENTION
It is the object of the present invention to provide an improved mower and
reel as well as a
retrofitable method of attachment of mower blades in existing reel mowers,
that would allow
for quick changing of the bed blades in the reel assembly without requiring
significant labor,
2o tools or disassembly of the reel to accomplish the changing of the blades.
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The objects of the invention are accomplished by creating a foliage mowing
apparatus
comprising a frame, said frame being transportable over foliage to be mowed; a
bedknife
mounted to said frame; and a reel unit rotatably mounted with respect to said
frame, said reel
unit and said bedknife being in foliage cutting relationship with each other;
wherein said
bedknife is magnetically attached to said frame. The magnetic attachment of
the bedknife to
the frame has numerous advantages over the mechanical or screw attachment of
all of the
prior art. Specifically, by making the bedknife magnetically attached to the
frame, it results
in a quick change type of assembly where the bedknife can basically be changed
by removing
1o it from the magnets and attaching another bedknife to the magnets in its
place without the
need to disassemble the reel unit at all from the remainder of the foliage
mowing apparatus to
access the screws holding the blade in place, as would be the case in the
prior art assemblies.
Commercial grade magnets are available of sufficient strength such that when
they are built
into the supporting frame for the bedknife in such a mowing apparatus, they
will hold the
bedknife in place in the absence of any abnormal force being encountered
thereon. In
addition to allowing for the quick changing of the blades, this magnetic
attachment method
also offers considerable safety advantages in terms of the integrity of the
mower unit, where
an obstruction such as a rock or the like might be encountered. Specifically,
unlike the case
of a screwed-into-place bedknife, the magnetically attached bedknife of the
present invention
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would, if sufficient force were encountered upon hitting an obstruction, be
pulled away from
its magnetic attachment and be released, potentially resulting in minimizing
or eliminating
damage to the reel if a rock or some other such unit is encountered. By
minimizing damage
to the blade and/or the reel in such a circumstance, maintenance costs can
again be
minimized.
While the Figures show 6 magnets in the bed bar, it will be understood that
any number of
magnets with adequate attractive force could be used, and all such variations
are
contemplated within the scope of the present invention.
Conventional magnets or electromagnets could be used to hold the bedknife in
place. Where
electromagnets are used, it would be even easier to release the blade from the
frame, since by
deactivation of the electromagnets the blades could easily be removed
therefrom. Even in
the case of non-electromagnets, that is to say standard magnets of commercial
strength, the
only tool which would potentially be required to remove a bedknife from the
frame would be
a blade or the like to pry the items apart. Obviously, the strength of the
magnets and number
of magnets used in the frame to hold the bedknife in place could be adjusted
or varied
depending on the circumstances.
2o It will also be understood that in addition to manufacturing a completed
new reel apparatus in
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accordance with the present invention, a retrofit frame/bed bar could also be
designed in
accordance with the present invention to be retrofitted onto various existing
reel mower
units. This would also be contemplated within the scope of the present
invention, insofar as
it would still constitute a support frame for a bedknife which would allow for
mechanical
attachment thereto.
The present invention yields a relatively "tool-less" bedknife changing
operation.
It is contemplated that alignment guides of some type might be provided on the
support
1 o frame for the bedknife and there might be some mating part or protrusion
from the bedknife
itself which would correspond with these alignment guides and allow for even
more quick
and precise placement of the blade in contact with the magnets on the support
frame. For
example, it is contemplated that small pegs or protrusions might be placed on
the bottom of
the support frame and corresponding holes might be made in the bedknife, which
holes could
then engage the projections from the support frame when the blade was put in
place, which
would allow for the immediate proper alignment of the bedknife in relation to
the support
framework and would also provide a significant degree of shearing hold or
mechanical hold
to the blade - whereby the magnets will resist any normal separating force
between the
supporting frame or the bed bar and the bedknife, and the pegs or other
similar mating or
corresponding protrusions or other similar alignment guides will provide
significant shear
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resistance against shearing forces exerted upon the bedknife during operation,
will still
allowing for release if the shearing forces are too great. It will be
understood that this
concept of a dowel or peg-like projection from the support framework is only
one possible
concept for the provision of an alignment guide or guides to help with the
quick changing
and proper holding in place of the bedknife of the present invention and that
any other types
of similar alignment guides as could be contemplated by someone skilled in the
art are
contemplated within the scope of the present invention.
1o DESCRIPTION OF THE DRAWINGS:
While the invention is claimed in the concluding portions hereof, preferred
embodiments are
provided in the accompanying detailed description which may be best understood
in
conjunction with the accompanying diagrams where like parts in each of the
several diagrams
are labeled with like numbers, and where:
Figure 1 is a perspective view of a self propelled driven lawn mower including
a reel
mower unit, shown as prior art;
2o Figure 2 is a partial side elevation of a partial section showing the reel
and bedknife
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mounting arrangement of the prior unit of Fig. 1;
Figure 3 is an exploded perspective view showing the reel unit and
typicallybedknife
mounting assembly of the prior art unit of Fig. 1 and 2;
Figure 4 shows the support frame of one embodiment of the present invention
from a
top view;
Figure 5 is a bottom view of the support frame of Figure 4; and
Figure 6 is a perspective view of an embodiment of the support frame and
bedknife
of the present invention.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS:
Figures 1 to 3 demonstrate a prior art reel cutting assembly in the field of
the present
invention and are discussed and further outlined above under the Background
section of this
patent application. Refernng to Figures 4 to 6, there is shown the method of
attachment of
the bedknife in a reel mower of the present invention. Figures 4 to 6 show one
embodiment
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of the present invention, although it will be understood that other
embodiments as would be
obvious to one skilled in the art are also contemplated within the scope of
the present
invention.
Shown in Figures 4 and 5 is the support frame, also known in the art as the
bed bar, from a
reel cutting assembly in accordance with the present invention. It will be
understood that the
present invention could be practiced in a number of fashions including by
manufacturing new
reel cutting assemblies in accordance with the present invention, or
alternatively, by
producing a retrofit bed bar or support frame kit which would allow the
magnetic blade
1o attachment of the present invention to be implemented on an existing mower.
Both such
approaches are contemplated within the scope of the present invention.
In any event, the bed bar shown in Figures 4 and 5 in accordance with the
present
invention it will be noted does not have any screw holes in it for attaching a
blade thereto.
There are shown the bar itself (42), which has 6 magnets (A) embedded therein.
The
magnets (A) are commercial strength magnets capable of holding the blade (39)
in place
during the normal operation of a reel cutting unit and the normal friction of
the reel and
grass thereon during normal cutting operations. The advantage to using the
magnets (A)
over screws as is the case in the prior art is that the blade (39) can be more
easily and
quickly attached and detached, potentially without tools, or with only the use
of a blade or
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the like to pry apart the blade (39) from the bed bar (42).
Also shown in Figure 4 (bottom view) are alignment guides (B) on the support
frame/bed
bar (42). These alignment guides in this case are a plurality of dowel-like
projections
from the bottom surface of the bed bar, which will match up with corresponding
receptacles in the blade (39) to properly guide the blade (39) into alignment
and position
upon attachment. These projections in this case will also provide
reinforcement against
shearing forces exerted on the blade during operation, while still allowing
the blade to
give way if the shearing forces encountered are too severe.
1o
Figure 6 also demonstrates the attachment of a support frame or bed bar (42)
of the
present invention to either a new or existing reel mower unit by way of
attachment
brackets or the like.
It will be understood that varying other types of alignment guides could be
used in place
of the dowel-like projections shown, and that any and all such guides as can
be
envisioned which would accomplish the goal of guiding the blade (39) into the
proper
position with the bed bar (42) and/or, but not necessarily, providing
reinforcement against
shearing foices, are contemplated within the scope of the present invention.
In cases
2o where the shearing forces exerted upon the blade in operation are great,
alignment guides
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of this nature will provide significant shearing reinforcement, while the
magnets will
counter any normal separating forces between the bar and the knife.
Also contemplated within the scope of the present invention are the methods of
retrofitting an existing reel mower with the bed bar and/or blade of the
present invention,
as well as the method of installing or replacing blades in a reel mower in
accordance with
the present invention.
It is also contemplated that the same method of attachment of a blade to a
mower unit
1o could be used to attach a blade in a rotary mower system, and such
embodiments, with the
necessary modifications, are also contemplated within the scope of the present
invention.
