Note: Descriptions are shown in the official language in which they were submitted.
2188~57
AERATOR APPARATUS
Background of the Invention
This invention relates to tine aerators and the
mechanical linkages which drive the tines into and out of the
turf.
It is known to provide an aerator mechanism with a drive
disc which rotates about a horizontally and laterally
extending axis. The upper portion of a main shaft is coupled
with the disc for rotation therewith. Mounted to the lower
portion of the main shaft is a tine which engages the ground
as the main shaft is driven up and down in a circular motion
with the drive disc. The tine forms benefitial holes or
openings in the ground which aerate the turf in a conventional
manner. ~ue to the momentum imparted to the main shaft by the
rotating drive disc, the lower portion of the main shaft can
be thrown generally forwardly or rearwardly from a vertical
position during operation. The impact of the tine against the
ground can further accentuate this throwing of the main shaft
fore and aft. Excessive swinging of the main shaft can cause
the tine to enter the ground at improper angles, thereby
causing the turf to be roughed up or otherwise damaged as it
enters or is pulled from the turf. It is known to provide
mechanisms for generally maintaining the main shafts in a
particular position which is thought to cause the least
disruption or damage to the turf as the openings are created.
However, these mechanisms which shift or return the main shaft
back to an ideal position tend to also urge the main shafts
back to this position while the tines are engaged within the
ground. mis shifting of the tines while they are in the
ground can cause a pitchforking effect which can dig up or
otherwise damage the turf being aerated. Furthermore, these
aerator mechanisms tend to fling a large amount of dirt into
the air as the aeration holes are created. me dirt can
become lodged in the return mechanisms and can cause the
return mechanisms to deteriorate and fail over extended
periods of use.
It would therefore be desirable to provide an aerator
mechanism that returns the mechanism or linkage to an ideal
tine-insertion configuration or neutral position but that does
i,, . 2l88~7
not damage or pitchfork the turf while the tine is inserted
within the ground. It would also be desirable to provide a
return mech~n;,qm whose durability is generally unaffected by
the presence of dirt and debris in the operating environment.
Summary of the Invention
The present invention provides an aerator mechanism
having a rotating cam wheel and a ram link thereattached. The
top portion of the cam wheel rotates about its axis in a
direction opposite to the aerator's direction of travel. A
tine positioned at the lower end of the ram link is driven
into and out of the ground as the cam wheel rotates. A
mounting mechanism operatively couples the lower end of the
ram link to the aerator's frame for ~;nt~;n;ng the ram link
in its generally vertically oriented neutral position. The
mounting mechanism includes first and second linkage members
pivotally coupled together between the frame and the lower
portion of the ram link. A flexible rubber biaser is in
constant abutment between the frame and the second link member
for returning the second link member to its neutral position
when the second link member has shifted in a first direction
from the neutral position. A blocker is positioned for
ab~LIl,en~ against the second link member for limiting the
motion of the second link member in the second direction away
from the neutral position.
The blocker according to the present invention allows the
aerator to operate effectively with only a relatively small
force being applied to the linkage for returning the linkage
to its neutral position. The biaser urges the second link
member against the blocker, and therefore the second link
member is brought to rest in its neutral position relatively
quickly without allowing the linkage to oscillate or swing and
without requiring a stiff return mech~n;qm that applies a
large force. Since the biaser applies only a relatively small
force for returning the linkage to its neutral position the
biaser does not cause the tine to tear up or pitchfork the
ground when the tine is in the ground. The biaser according
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to the present invention is designed to be generally
unaffected by the airborne dirt and debris that is present
during operation of the aerator.
Brief Description of the Drawinqs
Figure 1 is a side view of an aerator linkage according
to the present invention.
Figure 2 is an exploded perspective view of a mounting
mechanism according to the present invention as shown in
Figure 1.
Figure 3 iS a side view of the present invention as shown
in Figures 1 and 2.
Figure 4 is a side view of a first alternative embodiment
of the present invention.
Figure 5 is a side view of a second alternative
embodiment of the present invention.
Description of the Preferred Embodiment
Referring now to Figures 1, there is shown a side view of
an aerator mechanism 10 according to the present invention.
The aerator 10 includes a cam wheel 12 which rotates in the
direction of arrow A. The aerator machine 10 is travelling
across the ground surface in the direction of arrow B. As
seen in Figure 1, the top portion 14 of the cam wheel 12 is
driven about its axis of rotation 16 in a direction opposite
to the direction of travel B of the aerator machine 10. The
upper end portion 18 of a ram link 20 is pivotally coupled to
the cam wheel 12. A tine 22 is mounted to the lower end 24 of
the ram link 20 for penetrating the ground and forming an
aeration opening in the ground as the cam wheel 12 rotates
about its axis 16.
The lower portion 24 of the ram link 20 is also coupled
with the frame 26 of the aerator 10 by a mounting mechanism
28. The mounting mechanism 28 shown in Figures 1, 2 and 3
includes first and second link members 30 and 32. The first
link member 30 has one end 34 pivotally coupled with the lower
end of the ram link 20, and an opposite end 36 pivotally
coupled with the lower end portion 24 of the second link
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member 32. The upper end portion 38 of the second link 32 is
pivotally mounted to the frame 26. As best seen in Figure 2,
a bracket 40 is ridigly fixed to the frame 26. An elongate
bolt 42 is received within openings formed in a pair of brace
members 44. A pair of bearings 46 are received on the bolt 42
and pivotally support the upper end 38 of the second link
member 32. This mounting mechanism 28 serves to couple the
lower portion 24 of the ram link 20 to the aerator frame 26.
A buffer mechanism 48 is provided which helps maintain
the lower portion 24 of the ram link 20 in its proper position
generally directly beneath the axis of rotation 16 of the cam
wheel 12. As best seen in Figures 2 and 3, a biaser or
flexible rubber member 50 is mounting between the bracket 40
and an L-shaped member 52 which is fixed as by a weldment to
the upper portion 38 of the second link member 32. As the
lower portion 24 of the ram link 20 shifts forwardly in the
direction of forward travel A, the first link 30 will shift
forwardly therewith, causing the second link member 32 to
pivot in a counterclockwise direction about the bolt 42 as
viewed in Figures 1, 2 and 3. This pivoting of the second
link 32 causes the biaser 50 to become slightly compressed.
When compressed, the biaser 50 will act to bias or urge the
second link member 32 in a clockwise direction back to its
neutral position generally directly beneath the axis 16 of the
cam wheel 12 as shown in Figure 1. The biaser 50 thereby
generally keeps the lower portion 24 of the ram link 20 and
the tine 22 in the proper ooperating position.
As seen in Figures 1, 2 and 3, a blocker 54 is provided
in abutment between the bracket 40 and the L-shaped member 52
near the top portion 38 of the second link member 32. The L-
shaped member 52 abuts the blocker 54 when the second link
member 32 is in its neutral position. The blocker 54
generally prevents the second link member 32 from shifting in
the clockwise direction about the bolt 42 as viewed in Figures
1, 2 and 3.
Next, the operation of the mounting mechanism 28
according to the present invention will be described in
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greater detail. As the cam wheel 12 rotates about its
laterally and horizontally extending axis 16, the ram link 20
is driven up and down therewith, and the tine 22 mounted to
the lower end 24 of the ram link 20 is driven into and out of
5 the ground for forming aerating holes or openings in the turf
beneath the machine 10. The mounting mechanism 28 is coupled
between the aerator's frame 26 and the lower end portion 24 of
the ram link 20 for keeping the tine 22 in its proper position
as it is driven up and down. If the lower end 24 of the ram
link 20 were not coupled to the frame 26, the tine 22 might
easily be thrown too far forwardly or rearwardly as the cam
wheel 12 rotates. When the tine 22 is thrown forwardly, the
first link member 30 shifts forwardly therewith, and the
second link 32 pivots in a counterclockwise direction about
the bolt 42. The biaser 50 then becomes compressed and urges
or bises the second link member 32 back to its neutral
position corresponding to the ram link 20 being positioned
generally vertically as shown in Figure 1. The biaser 50
shown in Figures 1, 2 and 3 is a flexible rubber or elastic
material that extends between the bracket 40 and the L-shaped
member 52. The biaser 50 includes a first surface portion 56
which remains entirely and constantly in contact with a
portion of the bracket 40 or frame 26, and a second surface
portion 58 which remains entirely and constantly in contact
with the L-shaped member 52 of the second link member 32. The
first and second surface portions 56 and 58 remain in tight
operative abutment with the frame 26 and second member 32,
respectively, regardless of the pivotal position of the second
link member 32. This constant abutment of the surfaces 56 and
58 of the biaser 50 with the frame 26 and second link member
32 generally prevents soil and other debris from becoming
lodged therebetween. This is especially important since the
tines 22 tend to generate a large amount of airborne dirt and
debris as the tines 22 are driven into and out of the ground.
Dirt and debris would eventually errode and destroy the biaser
50 if allowed to become wedged between the biaser 50 and the
surfaces it contacts. The exclusion of dirt and debris from
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between the biaser 50 and the structures it abuts thereby
serve to enhance the durability and life of the biaser 50.
The biaser 50 will last a relatively long period of time
before needing replacement, thereby reducing repair costs and
5 machine downtime.
The present invention also includes a blocker or bumper
54. During operation, the tine 22 and lower portion 24 of the
ram link 20 tend to be thrown forwardly from the neutral
position by the driving force of the cam wheel 12 and
engagement of the tine 22 with the turf. However, the lower
portion 24 of the ram link 20 will generally not be thrown
rearwardly of the neutral position during operation. The
blocker 54 would generally prevent any rearward shifting of
the tine 22 from the neutral position by blocking the second
15 link member 32 from pivoting clockwise from its neutral
position as viewed in Figure 1. Furthermore, the blocker 54
serves as a backstop for the second link member 32 as it is
biased back to its neutral position by the biaser 50. If such
a blocker 54 were not provided the second link member 32 might
20 swing back and forth about the bolt 42 undesirably before
coming to rest in the neutral position. The linkage could
even be allowed to acheive a resonence frequency during
certain operating conditions. The blocker 54 according to the
present invention, however, serves as a backstop against which
25 the second link member 32 abuts as it is directed back to the
neutral position by the biaser 50.
The blocker 54 according to the present invention also
enables the aerator 10 to function effectively with a
relatively small force being applied by the biaser 50.
30 Without a blocker 54 according to the present invention, the
mechanism for returning the linkage to its neutral position
would be required to be relatively stiff and apply a large
force in order to cause the second link member 32 to rapidly
come to rest in its neutral position. A small force would
35 allow the second link member 32 to swing back and forth many
times before it would come to rest in the neutral position.
In fact, a small biasing force might allow the second link
21884S7
. i i
member to swing back and forth and acheive a resonance
frequency in certain operating conditions. But a stiff return
mechanism that would apply a large force would make the second
link 32 come to rest quickly in the neutral position.
However, a return mechanism that would apply a relatively
large force to the second link member 32 may cause the tine 22
to tear or rip the turf as the tine 22 enters and exits the
ground. A small biasing force would allow the tine 22 to
enter and exit the turf without tearing the ground, but, as
stated above, would not force the second link member 32 to
come to rest in the neutral position quickly. The present
invention provides a relatively small biasing force and
therefore will tend not to tear or rip the turf as the tine 22
enters and exits the ground. More particularly, the biaser 50
can be made of a rubber material having a 60 durometer
hardness and having a 2 inch diameter and a 1 5/8 inch depth.
The blocker 54 according to the present invention generally
prevents the second link member 32 from swinging back and
forth undesirably, and prevents the linkage from acheiving a
resonance frequency. The biasing force of the biaser 50
according to the present invention urges the second link
member 32 back to the neutral position where it abuts the
blocker 54, and the second link member 32 therefore quickly
comes to rest in the desired position. The blocker 54 thereby
allows the aerator 10 to functon effectively with a biaser 50
that applies only a relatively small force to return the
linkage to a neutral position, and generally prevents the
linkage from swinging excessively or acheiving a resonance
frequency.
An alternative embodiment of a mounting mechanism 62 is
shown in Figure 4. A bracket 64 is fixed to the frame 26 of
the aerator 10. An flexible elogate member or leaf spring 66
is mounted to the bracket 64. A blocker 54 is also mounted to
the bracket 64. The flexible member 66 serves as a second
linkage member 68. The first linkage member 30 is pivotally
coupled to the lower portion 70 of the flexible member 66 at
point 72. As the ram link 20 shifts forwardly from the
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neutral position during operation, the flexible member 66
flexes to allow its lower portion 70 to shift forwardly with
the ram link 20 and first link member 30. The internal
strength of the material of the flexible member 66 serves as a
biasing force for urging the first linkage member 30 and ram
link 20 back to the neutral position. The biasing force of
the flexible member 66 is relatively small and therefore does
not cause the tine 22 to rip or tear the turf as it enters and
exits the ground. The blocker 54 abuts against the flexible
member 66 for causing the flexible member 66 to come to rest
in its neutral position, and allows the flexible member 66 to
be returned to the neutral position with only a small biasing
force. The dirt and debris which is being thrown about by the
tine's interaction with the ground does not affect the
durability or life of the biasing mechanism, and generally
will not errode or destroy the flexible member 66.
Another alternative embodiment of a mounting mechanism 74
is shown in Figure 5. A second link member 76 is pivotally
coupled to a bracket 78 which is fixed to the aerator frame
26. The lower end portion 80 of the second link member 76 is
pivotally coupled with the first link member 30. A beam
member 82 extends outwardly from the bracket 78. A blocking
portion 84 of the second link member 76 serves as a blocker
for abuting against the beam 82 in the neutral position. A
compression spring 86 is positioned between a portion of the
second link member 76 and the beam member 82. When the second
link member 76 has pivoted in a counterclockwise direction
from the neutral position, the spring 86 applies a biasing
force to the second link member 76 to return the second link
member 76 to its neutral position. The compression spring 86
applies a relatively small force to the second link member 76
and therefore does not cause the tine 22 to rip or tear the
turf during operation. The abutment of the blocking portion
84 of the second link member 76 against the beam member 82
serves to quickly return the second link member 76 to its
neutral position even with a small biasing force being applied
by the compression spring 86. The airborne dirt and debris
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generated by the tines 22 digging into the turf generally does
not affect the durability of the compression spring 86, and
will not appreciably errode or destroy the spring 86.
