Note: Descriptions are shown in the official language in which they were submitted.
11'~0334
1 DOUBLE DISK OPENER ASSEMBLY AND
DISK BLADE THEREFOR
This invention relates generally to furrow openers for grain
drills or the like, and more specifically to an improved double
disk furrow opener and disk blades therefor.
Double disk openers are used extensively to provide a furrow
for receiving seed grains and/or fertilizer. Fig. 1 of the
drawings shows a double disk opener assembly 10 typical of pre-
vious devices and used for example with the John Deere Series
8000 and ~000 Grain Drills. A pair of flat disk blades 12 are
mounted for rotation on bearing screws 14 secured in tapped holes
provided in a machined face of a cast seed boot 16. Each screw
14 extends through an inner race of a bearing 18 mounted within a
bearing cap 20 which in turn is secured to the blade 12 by a
plurality of rivets 22. The flat blades 12 form a narrow V-
shaped cutting point 23 for establishing a furrow. Using flat
blades 12 allows the point 23 to remain narrow so that the force
necessary for the blades to penetrate the ground is minimized and
so that the amount of dirt thrown away from the furrow is
minimized.
To remove a blade from or secure a blade to the boot 16, a
bearing plug 24 on the end of the cap 20 is removed and a hexagon
or alan wrench is inserted into a hex recess in the head 28 for
turning the bearing screw 14. Two wrenches are necessary to
remove the two screws 24 and 14 each time a blade 12 is to be
replaced. Additionally, the seed boot 16 has to be tapped to
receive the screws 14 thereby increasing the cost of the assembly
10 .
Preventing the bearing screw 14 from coming out of the boot
16 has been a continuing problem requiring that the screw be
tightened by impact. The tapped hole often has threads that are
inferior to those, for example, in a nut, and therefore the
bearing screw cannot be tightened comparably to a nut and bolt
- 1 -
11;~0334
1 assembly. Additionally, torquing the bearing screw with an alan
wrench is more difficult than torquing a nut and bolt assembly
with a socket or bo~-end wrench or the like. Loss of complete
disk blade members commonly occurs as the screws 14 work loose
because of vibration during transport or operation of the
implement.
When a blade member such as that shown in Fig. 1 is replaced,
the bearing 18 is normally replaced at the same time whether or
not it is worn or otherwise damaged because it is secured to the
blade 12 by the riveted bearing cap 20. Although bolts could be
used to replace the rivets 22, they would have a tendancy to work
loose and would require additional time for removal when retriev-
ing a bearing 18. Each cap 20 protrudes outwardly from the axis
of rotation of the dlsk blade widening the assembly 10 and thereby
decreasing the distance between adjacent assemblies which hampers
the free flow of trash. When the assemblies 10 are spaced for
narrow row planting, the obstruction of trash flow by the caps 20
is particularly significant since row spacing may be on the order
of only about 6 inches. Small reductions in the width of the
assemblies can reduce trash flow problems. Often adjacent rows
will be staggered front-to-back to increase the spacing. If
staggering is used it is important that the openers cut a clean
furrow without the rear openers throwing dirt on the furrow cut
by the forward openers.
As is evident from Fig. 1, each blade member is fabricated
from several components rather than from a single piece of metal.
The bearing cap 20 is difficult to fabricate and requires the
additional step of riveting to the blade 12. Since the blade
itself is most likely ~o wear out and need replacement before
other components such as the bearing 18 or the cap 20, a double
disk assembly design is necessary which requires no replacement
of other components if only the blade is worn or damaged. It is
also desirable to eliminate the bearing cap and reduce the width
0334
1 of the assembly so that the trash flow characteristics of the
blade assemblies are improved.
In my United States Patent 4,196,779, issued 8 April 1980
and assigned to the assignee of the present application, a
mounting for a single disk opener is described in which the
riveted bearing cap is eliminated by mounting the bearing on a
support on the implement rather than on the blade. The blade
which is generally disk-shaped is secured with a single nut on a
shaft which depends outwardly from the bearing. It is desirable
to provide a double disk blade assembly using two bearings
mounted in a similar fashion on the cast boot so that the boot
does not have to be tapped for receiving a bearing screw such as
shown at 14 in Fig. 1. To provide the narrow, V-shaped point 23,
it is necessary that each bearing support a generally flat rather
than dish-shaped blade member. A disk blade is required which
can accommodate the above-described bearing while maintaining the
desired V-shaped point for good furrow forming characteristics.
Brief Summary of the Invention
It is therefore an object of the present invention to
provide an improved double disk blade opener assembly for a grain
drill or the like.
It is a further object to provide a double disk blade opener
assembly which eliminates the need for a tapped boot and for
bearing screws tightened into the boot, and which decreases the
incidence of lost blade members.
It is still a further object of the invention to provide
such a double disk blade opener assembly having improved trash
flow cnaracteristics while at the same time retaining a narrow,
V-shaped cutting point to maintain the soil penetrating and dirt
flow characteristics common to presently utilized flat disk blade
assemblies.
11'~0334
1 It is a further object of the invention to provide an opener
assembly utilizing a pair of disk blades, each with a unitary
structure which is generally flat and which has an outwardly
cupped central portion. Each blade is mounted on a shaft which
in turn is rotatably supported from a bearing carried by the seed
boot or arm member.
It is another object of the present invention to provide a
double disk blade opener assembly whexein the bearings for the
assembly are carried by the seed boot or arm. Extending
outwardly from each bearing is a transverse threaded shaft
rotatably supporting a generally flat, one-piece disk blade with
an outwardly cupped central portion. Each blade is secured
between a single nut threaded on a shaft and the bearing. The
cupped portion of each blade accommodates the bearing and the
section of the seed boot around the bearing, while the generally
flat outer portion of the blade provides a narrow, V-shaped
cutting point having furrow forming characteristics generally
identical to that of the previously used assemblies having flat
disk blades.
These and other objects and advantages of the present inven-
tion will become evident from the description of the preferred
embodiment and from the drawings.
Brief Description of the Drawings
Fig. 1 is a plan view, partially in section, of a double
disk furrow opener typical of the prior art;
Fig. 2 is a plan view, partially in section to better show
the arrangement of the bearings, of the double disk furrow opener
of the present invention;
Fig. 3 is a side view of the disk blade of the present
invention; and
Fig. 4 is a sectional view taken along lines 4--4 of the
blade shown in Fig. 3.
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11;~0334
1 Description of the Preferred Embodiment
The double disk blade opener assembly of the present inven-
tion is shown generally at 30 in Fig. 2. A seed boot 32, prefer-
ably cast from aluminum, is secured in a conventional manner to a
grain drill ~not shown) or the like. The boot 32 is cast with
outwardly facing openings 34 and 36. A pair of outwardly facing
bearing receiving seats 38 and 40 are also formed in the seed
boot 32. The openings and seats are cast so that no machining of
the boot is necessary. Supported on the seats 38 and 40 are
bearings 42 and 44, respectively. Each bearing includes an outer
race 46 and an inner race 48 having a bolt 50 extending there-
through. A flangette or cap structure 52 tightened in position
on the boot 32 by bolts 54 and 56 which pass through holes cast
in the boot 32 holds the outer race 46 of each bearing against
the corresponding bearing receiving seat. A more detailed des-
cription of the bearing arrangement can be found in the afore-
mentioned United States Patent. The holes are tapered slightly
to facilitate parting of the casting dies. The plane of the
seats 38 and 40 are angled slightly from the vertical so the
outwardly facing face extends slightly downwardly. The shafts 50
which extend outwardly from the inner races 48 therefore are
tilted downwardly.
Secured on the shafts 50 are a pair of disk blades 60. Each
blade 60 is secured between the inner race 48 and a securing nut
62 threaded on the end of the shaft 50. The shafts 50 have
opposed flats on their threaded ends which correspond to the
shape of an oblong hole 64 through the center of the disk 60. A
washer 64 is secured between the blade and the securing nut 62.
A dust cap member 66 is mounted on the shaft 50 inwardly of the
blade 60, and spacer washers 68 are provided on the shaft between
the cap 66 and the inner race of the bearing. Each shaft 50
includes a headed end 70 abutted against the inside face of the
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1 inner bearing race 48. As is evident from Fig 2, when the secur-
ing nut is tightened into position the blade 60, the shaft 50,
the washers 64 and 68, the dust cap member 66, and the inner race
48 rotate in unison about the axis of the shaft 50. The oblong
hole 64 which receives the flatted end of the shaft 50 prevents
relative rotation of the shaft and the blade 60 and provides a
means for preventing rotation of the shaft 50 as the securing nut
62 is tightened thereon.
The blade 60, which is preferably stamped out of a unitary
piece of high carbon steel, includes an outwardly cupped or hub
portion 72 near the center of the disk, and has a generally flat
radially outward portion 74 joined by a fillet or rounded
junction 75 to the hub portion. The hub portion 72 extends
around the bearing 42, the dust cap 66, and the spacer washers 68
and has a radius less than about 40 per cent of the radius of the
blade 60. The flat radially outward portion 74 of the blade
thereby is positioned substantially identically to the radially
outward portion of the blade 12 shown in Fig. 1. A narrow, V-
shaped cutting point 76 similar to the cutting point 23 of the
blade in Fig. 1 is formed. The cupped central portion 72 of the
blade 60 accommodates the bearing structure secured on the boot
32 while maintaining the cutting edge of the blade in a plane
which intersects the bearing 42. No bearing cap such as that
shown in 20 in Fig. 1 is necessary, and the blade can be
fabricated from a single piece of metal. The overall width of
the double disk blade assembly 30 is slightly less than the width
of the assembly 10 shown in Fig. 1, while at the same time the
narrow, V-shaped furrow cutting point is maintained.
The double disk opener arrangement constructed according to
the invention is mounted on a grain drill or similar implement
and is pulled through the soil so the V-shaped cutting point 76
forms a furrow therein. The spacer washers 68 maintain proper
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0334
1 separation of the disk blades 60 so that they just barely touch
at the tip of the cutting point. If a blade 60 becomes worn or
damaged requiring adjustment or replacement, the corresponding
jam nut 62 is removed from the threaded shaft 50 and a new blade
is attached or one or more of the spacer washers 68 are removed
so the disk blades touch at the tip. The narrower profile of tne
assembly 30 allows trash to flow more freely. The flat portions
74 of the blades 60 provide a narrow groove and allow each assem-
bly 30 to penetrate the ground easily. Additionally, the narrow
V-shaped cutting point prevents dirt from being thrown from one
furrow into the furrow cut by an adjacent assembly 30.
A single wrench is the only tool that is necessary to remove
a blade from or secure a blade on the shaft 50. The jam nut 62
on the shaft 50 holds the blade 60 in position and has less
tendency to work loose than the bearing screw 14 shown in Fig. 1.
The thread quality is generally better on the nut 62 and it can
be tightened on the shaft 50 easier and more securely than the
bearing screw can be tightened into the threaded hole. In the
event a bearing 42 or 44 fails, it can be replaced easily by
removing the bolts 54 and 56 and the flangette 52.
The cost of fabricating the cast boot 32 is reduced since it
requires no machining or tapping. No moving part of the assembly
is in frictional contact with the cast boot since the blades are
supported from the shafts extending from the inner races of the
bearings. The hub portion of each blade accommodates the bearing
structure and positions the plane of the cutting edge so that it
intersects the bearing.
