Note: Descriptions are shown in the official language in which they were submitted.
CA 02201385 1999-12-06
MOWER DECK
7. Field of the Invention
The present inventiion relatEa to material cutting implements for vehicles
such as
lawn and garden tractors, and more specifically to rotary mower decks and a
mulching
insert usable with those decks.
2. Background of the Invention
It is often desirable when u;>ing material cutting implements such as rotary
mowers,
to avoid the time and trouk~le required to collect cut material such as grass.
Further, due
to restrictions governing disposal of grass and similar cut materials, it is
often desirable to
mulch the material being cut and distribute it back over and down into the
uncut material.
Mulching of cut material also serves to provide nutrients for the uncut
material.
Accordingly, mulching mowers and mulching kits for converting rotary mowers to
a
mulching usage have been provided to meet these needs.
Frequently however', commercial mulching devices include obstructions within
the
mower deck cutting chamber that r~ssult in the accumulation of cut material at
gap or
pocket areas between the mulching device and the mower housing. These
accumulations,
if not routinely removed from the mower deck, impair the flow of air and cut
material within
the chamber as well as the efficiency of the mowing and mulching process, and
occasionally fall out of the deck, leaving an undesirable appearance to the
mowed area.
Summary of the Invention
It would therefore be desirable to provide a mulching insert that could be
used with
a conventional rotary mower deck, permitting it to be converted from side or
rear discharge
to mulching. Further, it would be desirable to provide a mulching insert
having a smooth
surface and fit within the deck, to minimize gaps, pockets and similar
obstructions therein.
It would further be desirable to improve material and air flow within the
chamber so that
the accumulations of material within the chamber are minimized, cutting and
mulching
efficiency is improved, clean out time is reduced and the finished appearance
of the
surface cut is improved.
CA 02201385 1999-12-06
Towards these ends, there is provided a mulching insert that can be quickly
attached or removed from conventional mower decks. The insert is also provided
with a
plug structure to block the opening in the mower deck where cut material is
normally
discharged.
The insert is composed of ,~ composite material with smooth surfaces that
nests in
the front and the one side portion of the cutting chamber. Its shape includes
a stepped
deck at the front portion of the chamber and above the path traversed by the
cutting tip
portion of the blade. This lowered deck surface provides a cross-sectional
area at the front
of the chamber where gra:~s is cut which is smaller than the cross-sectional
area in the
more open rear and one side of the cutting chamber where the clippings are
distributed.
As the clippings are cut arid moved through the smaller cross-sectional area,
they are
more closely confined and directed and are less likely to stick to the chamber
surfaces. At
the rear and one side of the chamber where the cross-sectional area is larger,
the flow
rate of the clippings and air is reduced to facilitate redistribution of the
material back onto
the ground.
The insert further includes a mulching ramp which is spaced radially inwardly
from
the stepped or lower deck surface and which extends from the front portion of
the chamber
to one side portion for directing clippings back down and in toward the
mulching portion of
the cutting blade for recutting.
In its preferred form, the insert is further provided with dual sections,
which are
usable with a two bladed rotary mower.
Brief Description of the Drawings
Figure 1 is a perspE~ctive view of a mowing deck with the insert attached, the
deck
being viewed from the bottom.
Figure 2 is a bottom view of the composite insert.
Figure 3 is a sectional view of the insert taken along lines 3-3 of Fig. 2
Figure 4 is a sectional view of the insert taken along lines 4-4 of Fig. 2.
Figure 5 is a sectional view of the insert taken along lines 5-5 of Fig. 2.
Figure 6 is a sectional view of the insert taken along lines 6-6 of Fig. 2.
Figure 7 is a sectional view of the insert taken along lines 7-7 of Fig. 2.
Figure 8 is a schematic plan view of a mower deck with the insert shown in
phantom and the removed discharge chute separated to one side.
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CA 02201385 1999-12-06
Figure 9 is a sectional view of the spindle blade and insert taken along line
9-9 of
Figure 8, with the blade, spindle, drive pulley and timing belt also being
illustrated
Description of the Preferred Embodiment
Looking first to Fig. 1, there is found a perspective view of the cutting
implement 10
and insert 12 as seen from beneath the implement housing 14. The housing or
deck 14
includes a generally horizontally exi:ending top deck member 16 and downwardly
extending
rear, front, left side, and right side members 18, 20 and 22. At the rearward
portion of the
deck 14 are semi-circular rings 24 which in the preferred embodiment extend
downwardly
from the deck surface 16 to provide a rear wall for the cutting chamber.
Within each of the
two cutting chambers, timed cutting blades 26 are rotatably supported on
respective
spindles 28
The blades 26 are supported to rotate in a plane space 30 below the top deck
member 16, about generally vertically extending axes 32. Each blade 26
includes outer tip
portions 34 adapted to cut material such as grass and radially inwardly spaced
cutting
portions 36 adapted for mulching or recutting of the grass clippings.
Looking also to Fig. 2, there is illustrated a bottom view of the mulching
insert 12
shown in Fig. 1. The insert 12 is pireferably made of a composite material
such as plastic
to facilitate the forming of smooth surfaces and minimize gaps, openings,
and/or pockets
between the surfaces of the insert 12 and those of the mower deck 14 since cut
material
could accumulate in those areas and influence air and material flow patterns
within the
cutting chamber.
Since the insert 12 used for two blades includes essentially similarly
functioning
sets of surfaces, only the IE~ft cutting chamber, as viewed in Fig. 1, and its
insert surfaces
will be reviewed in detail.
The insert 12 is adapted to he detachably mounted within a conventional mower
deck 14 having a discharge' opening 38 to one side as is shown in schematic
form in Fig.
8. To block the discharge opening 38, the insert 12 includes a plug section 40
on one side
(See Figs. 2 and 8). The insert 12 along with the ring portion 24 and top deck
member 16
define the cutting chamber for the k>lade 26. This chamber includes front,
rear, left and
right side portions 42, 44, 46 and 48.
Looking now to Fig:>. 1-7 and 9, it can be seen that the insert 12 includes a
first
generally horizontally extending ledge or second deck surface 50 spaced below
the
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CA 02201385 1999-12-06
housing deck member 16. This ledge surface 50 extends generally horizontally
between
the front portion 42 of the cutting chamber and the one side portion 44 where
clippings
would usually be discharged. It includes inner and outer edges 52 and 54 which
join first
and second vertical wall surfaces 56 and 58. The ledge or second deck surface
50,
extends generally from the front portion 42 of the cutting chamber to the one
side portion
46 and ends at a terminal edge 60 at the one side portion 48. The wall surface
58
extends vertically downwardly from the ledge 50 and terminates just outwardly
of the top
portion 34 of the blade 26.
A mulching ramp surface 62'. is provided in the insert 12 and also extends
generally
from the front portion 42 of the cutting chamber to the one side 48 thereof.
The ramp
surface 62 is radially spaced from the axis 32 of the blade 26 and is inclined
downwardly,
rearwardly and radially inwardly from the first deck member 16 to a terminal
edge 64
above the plane of operation 30 of the blade 26, see Fig. 9. The ramp surface
62 is joined
to the ledge surface 50 by the first vertical wall surface 56.
At their rear terminal edges 60 and 64, the ledge and ramp surfaces 50 and 62
are
also joined with an end surface 66 which is comprised of first and second
sections 68 and
70 , those sections 68 and 70 slopes upwardly sharply to the top deck member
16. The
cutting chamber is essentisilly open from the top deck surface 16 to the blade
26 at the
rear and other side portion; 44 and 46 of the chamber.
Attaching the insert 12 to the mower deck 14 in the preferred embodiment are
bolts
72 which also secure transition members 74 to the housing 14 to provide a
smooth air flow
from the top deck member 16 and on to the leading edge 76 of the ramp surface.
Looking now to Fig:.. 3-7, sectional views of the insert 12 taken along lines
3-3
through 7-7 of Fig. 2 are found. These views illustrate the ledge or second
deck member
50, the ramp surface 62 arid the first and second walls 56 and 58 at the noted
views
designated in Fig. 2.
Looking now to Fig. 8, there is illustrated in schematic form a plan view of
the deck
14 with the insert 12 identified with phantom lines. Spaced to one side is the
discharge
chute 78 that could be conventionally attached to the discharge opening 38 in
the right
side of the deck 14, but is iremoved when the insert 12 has been attached
within the deck
14. At the front of the deck 14, left and right caster wheels 80 and 82 are
carried.
Looking now to Fig. 9, there is illustrated a cross sectional view of the
insert 12
taken along lines 9-9 in Fig. 8. Also included are the blade 26, support
spindle 28, drive
pulley 84 and timing belt 8Ei. In this view, it can be seen that the tip
portion 34 of the
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CA 02201385 1999-12-06
blade 26 passes just beneath the ledge or second deck portion 50. Since the
cross
sectional volume of the cutting chamber in this area is smaller, movement of
the air and
clippings is confined and sireamline~d as the blade 26 rotates through that
area. With the
cutting chamber extending from the top deck member 16 to the blade 26 in the
rear and
one side portions 44 and 46 thereof, the cross-sectional area is larger than
that in front
and the air and clippings will move less rapidly, being dispersed and falling
back into the
mulching blade.
In operation, the use of the insert 12 within the mower housing 14 can convert
its
operation from one of traditional sidle discharge cutting implement to one of
a mulching
mower. In this way, the collection and disposal of grass or other types of
clippings is
avoided.
As the implement is advanced over the ground, the blade 26 will be rotating at
a
high speed to create a circular air fllow within the cutting chamber. The
blade 26 would
rotate counterclockwise as viewed in Fig. 1. Since the cross sectional area of
the cutting
chamber is reduced at the front and side portions 42 and 48 where the insert
12 is placed,
the cross-sectional area through which the air and clippings circulate is
smaller.
Accordingly, the velocity at which the air and clippings will move through
this confined area
will be greater than the velocity at vvhich they will move in the rear
sections where the
chamber is more open and has a larger cross-sectional area. This results in
the cut
material which is carried in the air stream to be rapidly conveyed along with
the air stream
below the ledge 50, reducing the tendency of the clippings to adhere surfaces
56, 58
adjacent the ledge 50 and extends beneath a portion of the ramp 62. As the cut
material
passes to the right or one side 48 uvhere the insert 12 again joins the upper
or top deck 16
of the mower housing 14, the cross-sectional area of the chamber volume
increases and
the velocity of the air and clippings will decrease, thereby allowing the cut
particles to fall
back into the blade path and/or to the ground. Those particles which do not
fall to ground
and are circulating in the air stream would be conveyed within the chamber and
then
deflected by the downwardly and inwardly sloping ramp surface 62 into the top
portion 34
and mulching portion 36 of the blade 26 for recutting again (see Fig. 9). In
this way, the
material being cut would be' circulated rapidly through the front and side
portion of the
cutting chamber, scouring the adjacent surfaces 50 and 58, then slow down in
the rear and
other side portions of the cutting chamber 44 or 46, to fall down or be
carried on to be
repeatedly mulched by the top portion 34 and outer edge of the mulching edge
36 of the
blade and then distributed.
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CA 02201385 1999-12-06
Since the insert 12 is comprised of a smooth material, the surfaces are
smooth, the
transitions between its surfiaces are smooth and the insert 12 blends with the
deck 14
components to minimize gaps, pockets and an accumulation of material in the
chamber.
Accordingly, turbulent air flow is also minimized. Further, there is less
likelihood that
material will collect in the walls of the cutting chamber, which would reduce
the cutting
efficiency unless frequently cleaned out by the operator. Also, the likelihood
that clumps of
material will collect within tile chamber and fall out, leaving an undesirable
appearance is
reduced.
With the present invention there is provided a mulching insert which can be
utilized
to either convert a typical side discharge mower to a mulching configuration
or be installed
as a permanent fixture within a ne~nr mower deck. The insert provides smaller
flow area in
the front section of the cutting chamber to move cut material to the rear and
side rapidly
where it can be dispersed as it enters the larger chamber area or fall out
onto the blade for
mulching. The ramp surface provides for deflection of circulating cut material
back into the
mulching portion of the blade for repeated cutting and distribution down into
the growing
grass.
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