Patent Description:
Mowers and mower conditioners are often employed to cut crop material, such as hay or grass, and deposit the cut crop into windrows in a field. For cutting smaller fields, a single pull-type mower or mower conditioner may be attached to the rear of an agricultural driving vehicle. For cutting large fields, the driving vehicle may push a front mounted mower or mower conditioner and optionally tow an additional rear mounted mower or mower conditioner.

A typical mower generally includes a frame, a hitch coupled to the vehicle, and a cutter bar such as a sickle bar or rotary disc cutter bar for severing the crop from the field. The mower may further include other elements such as a reel to assist crop feeding, an auger or belts to convey crop to a central discharge point, and a flail or set of rollers for conditioning crop as it is ejected rearwardly out of the mower. A disc cutter bar generally includes multiple juxtaposed cutterheads for cutting the standing crop. Each cutterhead may consist of a rotating disc with diametrically opposed cutting blades or knives affixed to the body of the disc.

The knives of a cutter bar are known wear items that are intended to be replaced or repaired with some frequency. However, many mowers have cutter bars that are structured in order to reduce the frequency of knives needing to be repaired or replaced. One known cause of irreparable knife damage is when the rotating knife contacts a large object or obstacle in a field, such as a rock. The knives typically rotate at high speeds and can be dulled, shattered, or otherwise broken when contacting the object or obstacle.

<CIT> discloses a disc cutter with a knife holder, which comprises a knife nut coupled to the disc body. A knife comprises a knife opening in which the knife nut is disposed. The knife is free to rotate about a rotation axis defined by the knife nut and is biased towards the disc body by a spring plate.

What is needed in the art is a way to reduce the frequency at which knives of a cutter bar need to be replaced or repaired.

Exemplary embodiments disclosed herein provide disc cutters with a knife and a spring plate carrying at least two protrusions such that in a first position the spring plate bears on the knife so a plane defined through a portion of the knife extends through the protrusions until an overload force applied to the knife forces the knife over at least one of the protrusions and moves the spring plate to a second position.

In some exemplary embodiments provided according to the present disclosure, a disc cutter for an agricultural implement includes: a disc body; a knife nut coupled to the disc body; a knife including a knife opening in which the knife nut is disposed, the knife being configured to rotate about a rotation axis defined by the knife nut; and a spring plate carrying at least two protrusions, the spring plate being biased towards the disc body such that in a first position the spring plate bears on the knife so a plane defined through a portion of the knife extends through the protrusions until an overload force applied to the knife forces the knife over at least one of the protrusions and moves the spring plate to a second position.

In some exemplary embodiments provided according to the present disclosure, a cutter bar for an agricultural implement includes a frame and a plurality of disc cutters carried by the frame. At least one of the disc cutters includes: a disc body including a disc opening; a bolt disposed in the disc opening; a knife nut including a nut opening in which the bolt is disposed; a knife including a knife opening in which the knife nut is disposed, the knife being configured to rotate about a rotation axis defined by the knife nut; and a spring plate carrying at least two protrusions, the spring plate being biased towards the disc body such that in a first position the spring plate bears on the knife so a plane defined through a portion of the knife extends through the protrusions until an overload force applied to the knife forces the knife over at least one of the protrusions and moves the spring plate to a second position.

In some exemplary embodiments provided according to the present disclosure, an agricultural mowing assembly includes an agricultural vehicle and an agricultural implement coupled to the agricultural vehicle. The agricultural implement has a cutter bar that includes a frame and a plurality of disc cutters carried by the frame. At least one of the disc cutters includes: a disc body including a disc opening; a bolt disposed in the disc opening; a knife nut including a nut opening in which the bolt is disposed; a knife including a knife opening in which the knife nut is disposed, the knife being configured to rotate about a rotation axis defined by the knife nut; and a spring plate carrying at least two protrusions, the spring plate being biased towards the disc body such that in a first position the spring plate bears on the knife so a plane defined through a portion of the knife extends through the protrusions until an overload force applied to the knife forces the knife over at least one of the protrusions and moves the spring plate to a second position.

One advantage that may be realized by exemplary embodiments provided according to the present disclosure is that the protrusions can hold the knife in a fixed cutting position until the knife contacts an object, causing the knife to swing to a swung-in position and reduce the risk of the knife breaking.

Another advantage that may be realized by exemplary embodiments provided according to the present disclosure is that the knife can automatically move back into the cutting position between the protrusions due to the centrifugal force that arises as the knife rotates.

Referring now to the drawings, and more particularly to <FIG>, there is shown an agricultural mowing assembly <NUM> which includes an agricultural vehicle <NUM> and at least one agricultural implement illustrated in the form of two mowing devices <NUM>, <NUM> coupled to the agricultural vehicle <NUM>. The agricultural mowing assembly <NUM> may include tandem front and rear mowing devices <NUM>, <NUM>, which operate in tandem to cut crop from the field. It should be appreciated that while only two mowers <NUM>, <NUM> are illustrated and described herein, the present disclosure is equally applicable to mowing assemblies that incorporate only one mowing device or more than two mowing devices.

The agricultural vehicle <NUM> generally includes a chassis <NUM>, a prime mover, wheels and/or tracks <NUM>, and a cab <NUM> for housing the operator. The chassis <NUM> may at least partially carry the front and rear mowing devices <NUM>, <NUM>. The vehicle <NUM> can be in the form of a tractor, self-propelled windrower, or any other desired agricultural vehicle.

The front and rear mowing devices <NUM>, <NUM> are connected to the chassis <NUM> of the agricultural vehicle <NUM>. The front mowing device <NUM>, for example, may be centrally mounted onto the driving vehicle <NUM> such that the agricultural vehicle <NUM> carries the front mowing device <NUM>. The rear mowing device <NUM> may be coupled to a tongue coupler on the chassis <NUM> by a pivotable tongue that can change the angular position of the rear mowing device <NUM> relative to the forward direction of travel. As shown, the mowing devices <NUM>, <NUM> are in the form of mower conditioners; however, the mowing devices <NUM>, <NUM> can be in the form of any desired mowing devices such as mowers, windrowers, cutter bars, or windrow inverters. Each mowing device <NUM>, <NUM> may include a frame <NUM>, <NUM>, a reel <NUM>, <NUM> with tines rotatably connected to the frame <NUM>, <NUM>, a cutter bar <NUM>, a conditioner <NUM>, e.g. at least one flail conditioner or at least two conditioning rollers <NUM>, and/or a crop gate <NUM>, e.g. swath gate and/or windrow forming shields, for directing the crop material out of the mowing device <NUM>, <NUM> and onto the field in a windrow or swath (as shown in <FIG> with respect to the rear mowing device <NUM>). The illustrated cutter bar <NUM> is in the form of a rotary disc cutter bar <NUM> with multiple disc cutters <NUM> carried by a frame of the cutter bar <NUM>.

Referring now to <FIG>, one of the disc cutters <NUM> is illustrated. The disc cutter <NUM> includes a disc body <NUM>, a knife nut <NUM> coupled to the disc body <NUM>, a knife <NUM> having a knife opening <NUM> in which the knife nut <NUM> is disposed, and a spring plate <NUM>. To couple the knife nut <NUM> to the disc body <NUM>, the disc body <NUM> may have a disc opening <NUM> formed therein and a bolt <NUM> disposed in the disc opening <NUM> of the disc body <NUM> and a nut opening <NUM> of the knife nut <NUM>, but it should be appreciated that this is exemplary only and the knife nut <NUM> may be coupled to the disc body <NUM> in other ways. When the bolt <NUM> is included, a bolt shield <NUM> may also be included to protect the bolt <NUM> from damage during operation. The knife <NUM> is configured to rotate about a rotation axis RA defined by the knife nut <NUM>, allowing the knife <NUM> to rotate between a cutting position (illustrated in <FIG> and <FIG>) and a swung-in position (illustrated in <FIG>), as will be described further herein. The spring plate <NUM> is biased in a biasing direction BD upwards towards the disc body <NUM> and bears on the knife <NUM>. The spring plate <NUM> may be biased in the biasing direction BD by virtue of, for example, being formed of a deformable material such as spring steel and loaded in a manner that biases the spring plate <NUM> in the biasing direction BD.

Referring specifically now to <FIG>, and <FIG> as well, it can be seen that the spring plate <NUM> carries at least two protrusions, illustrated as a pair of protrusions 361A, 361B. The spring plate <NUM> is movable between a first position (illustrated in <FIG> and <FIG>) and a second position (illustrated in <FIG>). In the first position, the spring plate <NUM> bears on the knife <NUM> such that a plane P defined through a portion of the knife <NUM> extends through the protrusions 361A, 361B. The plane P may extend, for example, through two opposite edges of each of the protrusions 361A, 361B. In this respect, the knife <NUM> can be held between the protrusions 361A, 361B when the spring plate <NUM> is in the first position to keep the knife <NUM> in the cutting position.

<FIG> illustrate what happens when the knife <NUM> is rotated in a rotation direction R towards an object <NUM>. Once the knife <NUM> contacts the object <NUM>, an overload force O is applied to the knife <NUM>. The overload force O applied to the knife <NUM> forces the knife <NUM> over one or more of the protrusions 361A, 361B, which is best illustrated in <FIG>. The knife <NUM> being forced over the protrusion(s) 361A, 361B causes the spring plate <NUM> to move to the second position, i.e., in a direction D opposite to the biasing direction BD in the illustrated embodiment. When the spring plate <NUM> is in the second position, the knife <NUM> may be in the swung-in position so the plane P extending through the knife <NUM> no longer extends through the protrusions 361A, 361B. In this respect, the protrusions 361A, 361B do not impede lateral or side-to-side movement of the knife <NUM> when the spring plate <NUM> is in the second position but do act against the knife <NUM> in the biasing direction BD to keep the knife <NUM> from translating vertically out of its operation plane. While the knife <NUM> may not be able to cut crop material in the swung-in position, the overload force O e.g., when contacting the object <NUM>, causing movement of the knife <NUM> from the cutting position to the swung-in position reduces the risk of the knife <NUM> being substantially damage because the overload force O causes movement of the knife <NUM> rather than the material of the knife <NUM> entirely absorbing the overload force O and deforming. Therefore, the knife <NUM> being forced over at least one of the protrusions 361A, 361B reduces the risk that the knife <NUM> dulls, shatters, or breaks when contacting the object <NUM>. The spring plate <NUM> with the protrusions 361A, 361B also reduces the risk of the knife <NUM> moving outside of the operational plane or zone and striking and damaging other components of the disc cutter <NUM>.

The protrusions 361A, 361B may be carried by the spring plate <NUM> in a variety of ways. In some embodiments, the knife <NUM> includes a pair of opposite edges 352A, 352B and at least one of the protrusions 361A, 361B bears on a respective one of the edges 352A, 352B when the spring plate <NUM> is in the first position. When the spring plate <NUM> is in the second position, one or both of the protrusions 361A, 361B may come out of contact with the edge 352A, 352B of the knife <NUM> that the protrusion(s) 361A, 361B contacts when the spring plate <NUM> is in the first position. In some embodiments, both of the protrusions 361A, 361B contacts a respective edge 352A, 352B of the knife <NUM> when the spring plate <NUM> is in the first position. Having the protrusion(s) 361A, 361B contact a corresponding edge 352A, 352B of the knife <NUM> helps the protrusion(s) 361A, 361B stabilize the knife <NUM> so the knife <NUM> does not spontaneously rotate about the rotation axis RA during normal operation of the disc cutter <NUM>.

In some embodiments, the spring plate <NUM> includes a bearing surface <NUM> that bears on a surface <NUM> of the knife <NUM> in the first position and is out of contact with the knife <NUM> when the spring plate <NUM> is in the second position, as can be appreciated from comparing <FIG> and <FIG>. When the spring plate <NUM> is in the second position, one or both of the protrusions 361A, 361B may bear on the surface <NUM> of the knife <NUM> rather than the bearing surface <NUM> so the knife <NUM> does not freely rotate about the rotation axis RA but must overcome the friction between the surface <NUM> and the protrusion(s) 361A, 361B to rotate. In some embodiments, the surface <NUM> is a surface of the knife <NUM> that does not face the disc body <NUM>, but it should be appreciated that the surface of the knife <NUM> facing the disc body <NUM> may also be the surface of the knife <NUM> that the bearing surface <NUM> contacts when the spring plate <NUM> is in the first position. Each of the protrusions 361A, 361B may extend from the bearing surface <NUM> so the knife <NUM> comes out of contact with the bearing surface <NUM> as the knife <NUM> is forced over at least one of the protrusions 361A, 361B. The protrusions 361A, 361B may, for example, be molded into the bearing surface <NUM> so the protrusions 361A, 361B are integrally formed with the bearing surface <NUM>. However, it should be appreciated that the protrusions 361A, 361B can be merely connected to the spring plate <NUM>, e.g., to the bearing surface <NUM>, so the spring plate <NUM> carries the protrusions 361A, 361B without the protrusions 361A, 361B being integrally formed in the spring plate <NUM>.

As best illustrated in <FIG> and <FIG>, each of the protrusions 361A, 361B may be formed to include a rounded surface 363A, 363B facing the knife <NUM>. Each of the rounded surfaces 363A, 363B may, for example, face the corresponding edge 352A, 352B of the knife <NUM> and contact the corresponding edge 352A, 352B when the spring plate <NUM> is in the first position and the knife <NUM> is in the cutting position. The rounded surfaces 363A, 363B may be shaped in a variety of ways to control the overload force O that causes the knife <NUM> to be forced over one or both of the protrusions 361A, 361B. A radius of each of the rounded surfaces 363A, 363B, for example, may be adjusted to increase or decrease the overload force O required to force the knife <NUM> to slide along the respective rounded surface 363A, 363B over one or both of the protrusions 361A, 361B. In some embodiments, the protrusions 361A, 361B may be formed with tapered surfaces, such as linearly tapered surfaces, rather than the rounded surfaces 363A, 363B. In such embodiments, the degree of tapering can control how much overload force O is required to force the knife <NUM> over the protrusion(s) 361A, 361B. It should thus be appreciated that the protrusions 361A, 361B can be shaped in a variety of ways.

Referring now to <FIG> and <FIG> specifically, it is illustrated how the knife <NUM> may be returned to the cutting position from the swung-in position and the spring plate <NUM> may be returned to the first position from the second position. As illustrated, rotation of the disc body <NUM> in the rotation direction R carries the knife <NUM> in the rotation direction R as well. As the knife <NUM> rotates in the rotation direction R, a centrifugal force CF acts on the knife <NUM>. The centrifugal force CF acts on the knife <NUM> in a direction that tends to cause the knife <NUM> to pivot about the rotation axis RA back towards the cutting position from the swung-in position. As the knife <NUM> pivots towards the cutting position from the swung-in position, the knife <NUM> may slide along one or both of the protrusions 361A, 361B, with the friction between the knife <NUM> and the protrusion(s) 361A, 361B partially controlling how much centrifugal force CF is needed for the knife <NUM> to return to the cutting position. In some embodiments, the centrifugal force CF needed to return the knife <NUM> to the cutting position is no greater than the overload force O required to force the knife <NUM> over at least one of the protrusions 361A, 361B, e.g., the centrifugal force CF needed to return the knife <NUM> to the cutting position may be less than the overload force O. When the knife <NUM> returns to the cutting position from the swung-in position, the spring plate <NUM> may momentarily come out of contact with the knife <NUM> and return to the first position from the second position so the knife <NUM> is once again in the plane P extending between the protrusions 361A, 361B. It should thus be appreciated that the knife <NUM> may automatically return to the cutting position and the spring plate <NUM> may automatically return to the first position due to the centrifugal force CF without the need for a user to stop operation of the disc cutter <NUM>.

In some embodiments, the protrusions 361A, 361B each define a respective protrusion length LA, LB and the knife <NUM> defines a knife length KL that extends in parallel with the protrusion lengths LA, LB when the spring plate <NUM> is in the first position. As used herein, the "length" is defined as a greatest dimension between two opposed edges of the protrusions 361A, 361B and the knife <NUM> and "parallel" is defined as being within <NUM>° of completely parallel. The knife length KL may also extend in parallel with the protrusion lengths LA, LB when the knife <NUM> is in the cutting position but not be parallel when the knife <NUM> is in the swung-in position. The protrusions 361A, 361B may be provided, for example, in the shape of ribs that have a greater length LA, LB than width. However, as will be described further herein, the protrusions 361A, 361B may have shapes other than that of ribs. Each of the protrusions 361A, 361B may also define a respective protrusion thickness TA, TB and the knife <NUM> may define a knife thickness KT that is greater than the protrusion thickness TA, TB of each of the protrusions 361A, 361B. In some embodiments, the protrusion thicknesses TA, TB are the same. Similarly, in some embodiments the protrusions 361A, 361B have the same general shape and/or dimensions, i.e., the protrusions 361A, 361B may be substantially identical. The knife <NUM> having a knife thickness KT that is greater than the protrusion thicknesses TA, TB differentiates the protrusions 361A, 361B from, for example, a recess that completely holds the knife <NUM> therein. However, it should be appreciated that in some embodiments the protrusion thickness TA, TB of one or both of the protrusions 361A, 361B is greater than the knife thickness KT.

Referring now to <FIG>, another exemplary embodiment of a spring plate <NUM> carrying protrusions <NUM> is illustrated. Unlike the previously described spring plate <NUM>, which carried two protrusions 361A, 361B, the spring plate <NUM> illustrated in <FIG> carries four protrusions 1061A, 1061B. As can be seen, two of the protrusions 1061A are on a first side of the knife <NUM> bearing on one of the edges 352A of the knife <NUM> and the other two protrusions 1061B are on an opposite side of the knife <NUM> bearing on the other edge 352B when the spring plate <NUM> is in the first position where the plane P extending through the knife <NUM> extends through the protrusions 1061A, 1061B. When an overload force acts on the knife <NUM>, the knife <NUM> is forced over one or more of the protrusions 1061A, 1061B to move the spring plate <NUM> to a second position. When the spring plate <NUM> is in the second position, the plane P extending through the knife <NUM> may not extend through the protrusions 1061A, 1061B. The protrusions 1061A, 1061B may, for example, be formed as nubs that extend from a bearing surface <NUM> of the spring plate <NUM>. In other respects, the spring plate <NUM> may be similar to the previously described spring plate <NUM>.

From the foregoing, it should be appreciated that the spring plate <NUM>, <NUM> carrying the protrusions 361A, 361B, 1061A, 1061B provided according to the present disclosure can keep the knife <NUM> in a desired horizontal plane P during normal operation of the disc cutter <NUM>. When the knife <NUM> contacts an object <NUM>, the overload force O applied to the knife <NUM> can force the knife <NUM> over one or more of the protrusions 361A, 361B, 1061A, 1061B rather than the force deforming and/or breaking the knife <NUM>. The knife <NUM> also tends to stay in the operating plane due to the spring plate <NUM>, <NUM> still acting on the knife <NUM> in the biasing direction BD even when the spring plate <NUM>, <NUM> is in the second position. The centrifugal force CF generated during rotation of the knife <NUM> can then return the knife <NUM> to the cutting position without any intervention or stoppage of the disc cutter <NUM>. It should thus be appreciated that the spring plate <NUM>, <NUM> provided according to the present disclosure protects the knife <NUM> in a manner that does not substantially hinder operation of the disc cutter <NUM>.

Claim 1:
A disc cutter (<NUM>) for an agricultural implement, comprising:
a disc body (<NUM>);
a knife nut (<NUM>) coupled to the disc body (<NUM>);
a knife (<NUM>) comprising a knife opening (<NUM>) in which the knife nut (<NUM>) is disposed, the knife (<NUM>) being configured to rotate about a rotation axis (RA) defined by the knife nut (<NUM>); and
a spring plate (<NUM>)
characterized in that the spring plate (<NUM>) carries at least two protrusions (361A,361B), the spring plate (<NUM>) being biased towards the disc body (<NUM>) such that in a first position the spring plate (<NUM>) bears on the knife (<NUM>) so a plane (P) defined through a portion of the knife (<NUM>) extends through the protrusions (361A,361B) until an overload force applied to the knife (<NUM>) forces the knife (<NUM>) over at least one of the protrusions (361A,361B) and moves the spring plate (<NUM>) to a second position.