GB2043418A - Double disk furrow opener - Google Patents

Abstract

A double disk furrow opener for a seed drill has two bearings 42, 44 supported on opposite sides of a seed boot casting or other support arm 32 mounted on the implement. Each bearing supports a threaded shaft 50 which extends outwardly therefrom to a blade-receiving end. Two flat disk blades 60 each fabricated from a single piece of sheet metal and having opposed outwardly cupped central hub portions to accommodate the bearings are secured on and rotate with the shafts. Mounting the bearings in the arm 32 rather than in bearing caps on the blade decreases the overall width of the opener and increases trash flow between adjacent openers. <IMAGE>

Description

SPECIFICATION Double disk furrow opener This invention relates generally to double disk furrow openers such as are used in seed drills.

In such devices two disks are mounted on fitted spindles, one on either side of a support arm, so that the disks converge to their bottom peripheral regions.

Double disk openers are used extensively to provide a furrow for receiving seeds and/or fertilizer. Many known constructions employ flat disks on fixed bolt-like spindles. However it is normally desired to employ rolling bearings. Fig. 1 of the drawings shows a double disk opener assembly 10 typical of devices with ball bearings and used for example with the John Deere Series 8000 and 9000 Grain Drills. Two flat disk blades 1 2 are mounted for rotation on bearing screws 14 secured in tapped holes provided in a machined face of a cast seed boot 1 6. Each screw 14 extends through an inner race of a bearing 1 8 mounted within a bearing cap 20 which in turn is secured to the blade 1 2 by a plurality of rivets 22.The inner race is fixed by the screw to the boot; the outer race is fixed in the cup. The flat blades 1 2 form a narrow Vshaped cutting point 23 for establishing a furrow. Using flat blades 1 2 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 change a blade, a bearing plug 24 in the end of the cap 20 is removed and a hexagon or alan key is inserted into a hexagonal recess in the head 28 for turning the bearing screw 1 4. A separate spanner and key are necessary to remove the two screws 24 and 14 each time a blade 1 2 is to be replaced. Additionally, the seed boot 1 6 has to be tapped to receive the screws 14, thereby increasing the cost of the assembly 10.

Preventing the bearing screw 1 4 from coming out of the boot 1 6 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 assembly. Additionally, tightening the bearing screw with an alan key is more difficult than tightening a nut and bolt with say a socket or box spanner. Loss of complete disk blade members commonly occurs as the screws 1 4 work loose because of vibration during transport or operation of the implement.

When a blade such as that shown in Fig. 1 is replaced, the bearing 1 8 is normally replaced at the same time whether or not it is worn or otherwise damaged because it is secured to the blade 1 2 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 retrieving a bearing 1 8. Each cap 20 protrudes outwardly from the axis of rotation of the disk blade, so 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 as little as about 1 5 cm.Small reductions in the width of the assemblies can reduce trash flow problems.

Often adjacent rows will be staggered front-toback 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 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 1 2.

Since the blade itself is most likely to wear out and need replacement before other components such as the bearing 1 8 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 of the assembly so that the trash flow characteristics of the blade assemblies are improved.

With a view to at least partially overcoming such problems the present invention provides a double disk furrow opener for an agricultural implement, comprising a support arm, two shaft members rotatably supported by and extending laterally from opposite sides of the support arm, two disk blades, each secured to a one of the shafts for rotation therewith, each blade having a generally flat radially outward portion and a central cupped hub portion with an aperture receiving the corresponding shaft therethrough, the hub portion of each blade member being concave toward the support arm and the shafts being so fitted that the radially outward portions of the blades converge near the lower portion of the opener to form a V-shaped cutting point.

In the preferred embodiment of the invention rolling bearings are carried by the seed boot or arm. Extending outwardly from the inner race of each bearing is threaded shaft supporting a generally flat, one-piece disk blade with an outwardly cupped central portion. Each blade is secured between a single nut threaded on the corresponding 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 pro vides a narrow, V-shaped cutting point having furrow forming characteristics generally identi cal to that of the previously used assemblies having flat disk blades.

The invention will be described in more detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view, partially in section, of the above described double disk furrow opener typical of the prior art; Figure 2 is a plan view, partially in section to better show the arrangement of the bear ings, of a double disk furrow opener embody ing the present invention; Figure 3 is a side view of one disk blade of the furrow opener; and Figure 4 is a sectional view taken along lines 4-4 of the blade shown in Fig. 3.

In the double disk blade opener 30 shown in Fig. 2, a seed boot or support arm 32, preferably cast from aluminium, is secured in a conventional manner to a seed drill (not shown) or other implement. The boot 32 is cast with outwardly facing openings 34 and 36. A pair of outwardly facing counter bores 38 and 40 for bearings are also formed in the seed boot 32. The openings and counter bores are cast so that no machining of the boot is necessary. The holes are tapered slightly to facilitate parting of the casting dies.

Supported in the counter bores 38 and 40 are bearings 42 and 44, respectively. Each bearing includes an outer race 42 and an innter race 48 having a bolt 50 extending therethrough. 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 seat provided by the corresponding counter bore. The axes of the holes 34, 36 and counter bores 38 and 40 are tilted slightly so that the shafts 50 which extend outwardly from the inner races 48 likewise have a slightly downward tilt.

Secured on the shafts 50 are two disk blades 60. Each blade 60 is secured between the inner race 48 and a securing nut 62 tightened on to 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 centre of each disk 60. A washer 64 is held between the blade and the securing nut 62. A dust cap 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 inner bearing race 48. As is evident from Fig. 2, when the securing nut is tightened into position, the blade 60, the shaft 50, the washers 64 and 68, the dust cap 66, and the inner race 48 are clamped together to 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 centre of the disk, and has a generally flat radially outward portion 74. The hub portion 72 extends around the bearing 42, the dust cap 66, and the spacer washers 68. The flat radially outward portion 74 of the blade thereby is positioned substantially identically to the radially outward portion of the blade 1 2 shown in Fig. 1. A narrow, Vshaped 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 is mounted on a grain drill or similar implement and is pulled through the soil so that the V-shaped cutting point 76 forms a furrow therein. The spacer washers 68 maintains proper 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 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 that the disk blades touch at the tip. The narrower profile of the assembly 30 allows trash to flow more freely. The flat portion 74 of the blades 60 provide a narrow groove and allow each assembly 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 spanner wrench is the only tool that is necessary to remove a blade from or secure a blade on the shaft 50. The 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. If 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.

Claims (7)

1. A double disk furrow opener for an agricultural implement, comprising a support arm, two shaft members rotatably supported by and extending laterally from opposite sides of the support arm, two disk blades, each secured to a one of the shafts for rotation therewith, each blade having a generally flat radially outward portion and a central cupped hub portion with an aperture receiving the corresponding shaft therethrough, the hub portion of each blade member being concave toward the support arm and the shafts being so fitted that the radially outward portions of the blades converge near the lower portion of the opener to form a V-shaped cutting point.

2. A double disk furrow opener according to claim 1, wherein each disk blade is fabricated from a single piece of sheet metal.

3. A double disk furrow opener according to claim 1 or 2, wherein the hub portion of each disk blade includes a central flattened area.

4. A double disk furrow opener according to claim 1, 2 or 3, wherein each shaft is mounted in a bearing fixed to the support arm and projecting into the hub of the corresponding disk blade.

5. A double disk furrow opener according to claim 4, wherein said bearing is a rolling bearing having inner and outer races with the outer race secured against the support arm, and wherein each shaft comprises a threaded bolt extending through the inner race, a nut being screwed on to the bolt so that the blade is clamped between the inner race and the nut for rotation in together therewith.

6. A double disk furrow opener according to claim 5 or 6, wherein the support arm is a casting with a pair of opposed, laterally outwardly facing bearing-receiving cast seats.

7. A double disk furrow opener substantially as hereinbefore described with reference to and illustrated in Figs. 2 to 4 of the accompanying drawings.