Patent Description:
Agricultural harvesting machines, such as balers, are used to consolidate and package crop material so as to facilitate the storage and handling of the crop material for later use. In the case of hay, a mower-conditioner is typically used to cut and condition the crop material for windrow drying in the sun. In the case of straw, an agricultural combine discharges non-grain crop material from the rear of the combine defining the straw (such as wheat or oat straw) which is to be picked up by the baler. The cut crop material is typically raked and dried, and a baler, such as a large square baler or round baler, straddles the windrows and travels along the windrows to pick up the crop material and form it into bales.

A round baler may generally include a frame, supported by wheels, a pickup unit to engage and lift the crop material into the baler, a cutting unit, a main bale chamber for forming a bale, and a wrapping mechanism for wrapping or tying a material around the bale after it has been formed in the main bale chamber. As the baler is towed over a windrow, the pickup unit lifts the crop material into the baler. Then, the crop material may be cut into smaller pieces by the cutting unit. As the crop material enters the main bale chamber, multiple carrier elements, e.g. rollers, chains and slats, and/or belts, will begin to roll a bale of hay within the chamber. These carrier elements are movable so that the chamber can initially contract and subsequently expand to maintain an appropriate amount of pressure on the periphery of the bale. After the bale is formed and wrapped by the wrapping mechanism, the rear of the baler is configured to open for allowing the bale to be discharged onto the field.

The cutting unit includes knives that cut crop material fed toward the knives by a rotor or other conveyance device. As crop material is fed toward the knives, the knives cut the crop material into smaller pieces. In some instances, the load on the knives from the crop material can cause damage to the cutting unit. A cutting unit with overload protection is known from <CIT>.

What is needed in the art is a way to protect the cutting unit from damage during operation.

Exemplary embodiments provided according to the present disclosure include an overload protection assembly with slide members that slide relative to one another to retract a knife tray when an overload force is applied to one or more knives carried by the knife tray.

In some exemplary embodiments provided in accordance with the present disclosure, a cutting unit for an agricultural baler, includes: a plurality of knives; a knife guard with at least one opening; a knife tray carrying the knives, the knife tray being movable between an exposed position where the knives extend through the at least one opening and a retracted position where the knives are shielded by the knife guard; and an overload protection assembly including a first slide member coupled to the knife tray and having a first engagement surface and a second slide member having a second engagement surface that is engaged with the first engagement surface. The first slide member and the second slide member are held together and slidable relative to one another such that the first slide member slides relative to the second slide member to move the knife tray from the exposed position to the retracted position when an overload force is applied to at least one of the knives. The first slide member or the second slide member comprises a locking projection on its engagement surface and the other of the first slide member and the second slide member comprises a recess holding at least a portion of the locking projection. The locking projection and the recess are configured to come out of full engagement when the knife tray moves from the exposed position to the retracted position.

In some exemplary embodiments provided in accordance with the present disclosure, an agricultural baler includes: a chassis; a pickup carried by the chassis and carrying a plurality of tines, the pickup being configured to rotate the tines and pickup crop material; and a cutting unit carried by the chassis. The cutting unit which is carried by the chassis includes: a plurality of knives; a knife guard with at least one opening; a knife tray carrying the knives, the knife tray being movable between an exposed position where the knives extend through the at least one opening and a retracted position where the knives are shielded by the knife guard, the knives being configured to cut crop material picked up by the pickup when extending through the at least one opening; and an overload protection assembly including a first slide member coupled to the knife tray and having a first engagement surface and a second slide member including a second engagement surface that is engaged with the first engagement surface. The first slide member and the second slide member are held together and slidable relative to one another such that the first slide member slides relative to the second slide member to move the knife tray from the exposed position to the retracted position when an overload force is applied to at least one of the knives. The first slide member or the second slide member comprises a locking projection on its engagement surface and the other of the first slide member and the second slide member comprises a recess holding at least a portion of the locking projection. The locking projection and the recess are configured to come out of full engagement when the knife tray moves from the exposed position to the retracted position.

One possible advantage that may be realized by exemplary embodiments provided according to the present disclosure is that the knives can be retracted when the overload force, which may originate from a blockage, is applied to one of the knives to protect the cutting unit from being damaged.

Another possible advantage that may be realized by exemplary embodiments provided according to the present disclosure is that the overload protection assembly is an elegant solution that can be easily manufactured and installed.

The terms "forward", "rearward", "left" and "right", when used in connection with the agricultural baler and/or components thereof are usually determined with reference to the direction of forward operative travel of the towing vehicle, but they should not be construed as limiting. The terms "longitudinal" and "transverse" are determined with reference to the fore-and-aft direction of the towing vehicle and are equally not to be construed as limiting.

Referring now to the drawings, and more particularly to <FIG>, an exemplary embodiment of a round baler <NUM> is shown to include a chassis terminating forwardly in a tongue <NUM> and rearward slightly beyond a transverse axle 12a to which a pair of wheels 12b (only one shown) is mounted, thus forming a wheel supported chassis. The chassis supports a series of belts <NUM> and floor rolls, which together with a first sidewall 14a (shown in the breakout) behind and generally parallel to cover panel <NUM> and a second sidewall 14b, collectively forming a bale-forming chamber <NUM>. Cut crop material is picked up by a plurality of tines <NUM> of a transverse pickup <NUM> and fed through a harvesting assembly into the bale-forming chamber <NUM> where it is formed into a cylindrically shaped bale by a series of conveyor belts <NUM>. The bale is then optionally wrapped with twine or a net wrapping material dispensed from a wrapping mechanism generally behind shield <NUM>. Upon completion of the optional wrapping process, the tailgate <NUM> pivots upwardly about pivot points 51a, 51b and the bale is discharged onto the ground. It should be appreciated that while the baler <NUM> is illustrated and described as a round baler, in some embodiments the baler <NUM> is configured as a square baler.

Referring still to <FIG>, and referring now to <FIG> as well, a cutting unit <NUM> is carried by the chassis and includes a plurality of knives <NUM>, a knife guard <NUM> with one or more openings <NUM>, and a knife tray <NUM> that carries the knives <NUM>. As illustrated in <FIG>, the knife tray <NUM> may assume an exposed position where the knives <NUM> extend through the opening(s) <NUM> of the knife guard <NUM>. When the knives <NUM> extend through the opening(s) <NUM>, the knives <NUM> may cut crop material that is picked up and fed rearwardly by the pickup <NUM>. In some embodiments, the cutting unit <NUM> includes a rotor <NUM> that rotates to force the collected crop material against the knives <NUM> to cut the crop material into smaller pieces.

During operation, the knives <NUM> come into contact with conveyed crop material to cut the crop material into smaller pieces. In certain instances, such as during a blockage, the load exerted on the knives <NUM> by the moving crop material is excessively high. If the knives <NUM> are held stationary during such loading, damage to the cutting unit <NUM> may result. Further, the knives <NUM> can make it more difficult to clear the blockage by reducing clearance for the blockage to pass. Known solutions, such as providing each knife with a spring-loaded protection mechanism, have been effective to reduce the load experienced by the knives but are complicated and difficult to manufacture.

To overcome some of the previously described issues with known cutting units, and referring now to <FIG> and <FIG> as well, the cutting unit <NUM> provided according to the present disclosure includes an overload protection assembly <NUM> with a first slide member <NUM> coupled to the knife tray <NUM> and a second slide member <NUM>. The first slide member <NUM> has a first engagement surface <NUM> and the second slide member <NUM> has a second engagement surface <NUM> that is engaged with the first engagement surface <NUM>. The slide members <NUM>, <NUM> are held together and slidable relative to one another such that the first slide member <NUM> slides relative to the second slide member <NUM> to move the knife tray <NUM> from the exposed position (illustrated in <FIG>) to a retracted position (illustrated in <FIG>) when an overload force, designated by arrow OF, is applied to at least one of the knives <NUM>. The overload force OF may originate from a blockage of crop material that is forced against the knives <NUM> by the rotor <NUM>. When the knife tray <NUM> is in the retracted position, the knives <NUM> are shielded by the knife guard <NUM> by, for example, being housed within the knife guard <NUM> and not extending out of the opening(s) <NUM>. Each of the slide members <NUM>, <NUM> may contact a respective roller <NUM>, <NUM> that can slide along a track or other surface to allow the slide members <NUM>, <NUM> to slide relative to one another.

Resistance to the sliding may be provided by frictional forces between the engagement surfaces <NUM>, <NUM> engaging one another. It should thus be appreciated that tuning of the overload force that is required to slide the first slide member <NUM> to move the knife tray <NUM> to the retracted position may be accomplished by, for example, adjusting the frictional forces between the engagement surfaces <NUM>, <NUM> of the slide members <NUM>, <NUM>. In some embodiments, one or more springs, illustrated as a first spring 350A and a second spring 350B, bear on the first slide member <NUM> and/or the second slide member <NUM> to hold the slide members <NUM>, <NUM> together. The spring force of each spring 350A, 350B can be adjusted to tune the frictional force between the engagement surfaces <NUM>, <NUM> by adjusting the force holding the slide members <NUM>, <NUM> together. Each of the springs 350A, 350B may be disposed about a respective spring rod <NUM>, <NUM>. Each of the spring rods <NUM>, <NUM> may extend through respective rod openings 353A, 353B, 354A, 354B formed in the slide members <NUM>, <NUM>. In some embodiments, the rollers <NUM>, <NUM>, which may be in the form of roller bearings, that bear on the slide members <NUM>, <NUM> are coupled to the spring rods <NUM>, <NUM>.

According to the invention, one of the slide members <NUM>, <NUM>, illustrated as the second slide member <NUM>, has a locking projection <NUM> on its engagement surface <NUM> and the other of the slide members <NUM>, <NUM>, illustrated as the first slide member <NUM>, has a recess <NUM> holding ta least a portion of the locking projection <NUM> and which may be formed in the first engagement surface <NUM>. While the locking projection <NUM> is illustrated and described as extending from the second engagement surface <NUM> of the second slide member <NUM> and the recess <NUM> is illustrated and described as being formed in the first engagement surface <NUM> of the first slide member <NUM>, the locking projection <NUM> can be formed on the first slide member <NUM> and the recess <NUM> can be formed in the second slide member <NUM> to achieve a similar effect, in accordance with the present disclosure. The locking projection <NUM> and the recess <NUM> may be formed in the slide members <NUM>, <NUM> by casting the slide members <NUM>, <NUM> or using any other suitable manufacturing technique.

According to the invention, the entirety of the locking projection <NUM> is held within the recess <NUM> when the knife tray <NUM> is in the exposed position, i.e., when the locking projection <NUM> and the recess <NUM> are in full engagement. When the knife tray <NUM> moves from the exposed position to the retracted position, as illustrated in <FIG>, the locking projection <NUM> and the recess <NUM> come out of full engagement as the first slide member <NUM> slides relative to the second slide member <NUM>. The overload force OF may be tuned by adjusting the relative shapes of the locking projection <NUM> and the recess <NUM>. As illustrated in <FIG>, the locking projection <NUM> may include a curved surface <NUM> and the recess <NUM> may have a curved shape that corresponds to the curved surface <NUM>, allowing the recess <NUM>, and thus the first slide member <NUM>, to slide relative to the locking projection <NUM> and the second slide member <NUM> when the overload force OF is applied to one or more of the knives <NUM>. It should thus be appreciated that the overload force OF that slides the first slide member <NUM> relative to the second slide member <NUM> to move the knife tray <NUM> to the retracted position may be tuned by adjusting the relative shapes of the locking projection <NUM> and the recess <NUM>.

In some embodiments, and referring now to <FIG> as well, the cutting unit <NUM> includes an actuator <NUM> that is coupled to the second slide member <NUM> and configured to slide the second slide member <NUM> relative to the first slide member <NUM>. The actuator <NUM> sliding the second slide member <NUM> relative to the first slide member <NUM> when the locking projection <NUM> and the recess <NUM> are out of full, or any, engagement can re-engage the locking projection <NUM> and the recess <NUM>. When the locking projection <NUM> and the recess <NUM> are re-engaged, the actuator <NUM> can move the slide members <NUM>, <NUM> to return the knife tray <NUM> to the exposed position from the shielded position. It should be appreciated that the actuator <NUM> can also move the slide members <NUM>, <NUM> when they are engaged to move the knife tray <NUM> from the exposed position to the shielded position, and vice versa. In other words, extension and retraction of the actuator <NUM> can both control movement of the knife tray <NUM> when the locking projection <NUM> and the recess <NUM> are engaged and also slide the second slide member <NUM> relative to the first slide member <NUM> to re-engage the locking projection <NUM> and the recess <NUM> when they are out of full and/or partial engagement.

Referring specifically to <FIG>, it is illustrated that the first slide member <NUM> has slid rearwardly relative to the second slide member <NUM> so the recess <NUM> and the locking projection <NUM> are not fully engaged and the knife tray <NUM> is in the shielded position so the knives <NUM> are not exposed through the opening(s) <NUM> of the knife guard <NUM>. The actuator <NUM> may be activated to retract an actuator rod <NUM> that is coupled to the second slide member <NUM> so the second slide member <NUM> also slides rearwardly, relative to the first slide member <NUM>, until the locking projection <NUM> of the second slide member <NUM> re-engages the recess <NUM> of the first slide member <NUM>. When the locking projection <NUM> and the recess <NUM> are re-engaged, as illustrated in <FIG>, the actuator <NUM> may be activated to extend the actuator rod <NUM> so the slide members <NUM>, <NUM> slide forwardly to move the knife tray <NUM> to the exposed position and extend the knives <NUM> through the opening(s) <NUM> of the knife guard <NUM>. To make it easier to re-engage the locking projection <NUM> and the recess <NUM>, a stop <NUM> may be provided that limits sliding of the first slide member <NUM> relative to the second slide member <NUM>.

In some embodiments, and referring specifically to <FIG>, the cutting unit <NUM> includes a proximity sensor <NUM> that is configured to output a retracted signal when the knife tray <NUM> moves to the retracted position. In some embodiments, the proximity sensor <NUM> is carried by one of the slide members <NUM>, <NUM> and is configured to output the retracted signal when the proximity sensor <NUM> senses that the slide members <NUM>, <NUM> have slid relative to each other. Relative sliding between the slide members <NUM>, <NUM> during operation tends to correspond to movement of the first slide member <NUM> relative to the second slide member <NUM> and an accompanying movement of the knife tray <NUM> to the retracted position.

A controller <NUM> may be operatively coupled to the proximity sensor <NUM> and the actuator <NUM>. The controller <NUM> may be configured to receive the retracted signal that is output by the proximity sensor <NUM> and output a re-engagement signal to the actuator <NUM> to cause the actuator <NUM> to slide the second slide member <NUM> to re-engage the locking projection <NUM> and the recess <NUM>, as previously described. The controller <NUM> may be configured to also output a return signal to the actuator <NUM> to cause the actuator <NUM> to slide the second slide member <NUM> and the first slide member <NUM> and return the knife tray <NUM> to the exposed position. The controller <NUM> may be configured to output the return signal, for example, after outputting the re-engagement signal to cause re-engagement of the locking projection <NUM> and the recess <NUM>.

In some embodiments, the controller <NUM> is further configured to output a retracted warning signal to a display responsively to receiving the retracted signal. The display may be, for example, disposed in an operator cab of a towing vehicle that is towing the baler <NUM> and configured to display a warning that the knife tray <NUM> has retracted in response to receiving the retracted warning signal. The controller <NUM> may be configured to receive a re-engage and return signal, from the display or elsewhere, after outputting the retracted warning signal and responsively output the re-engagement signal and the return signal. Thus, it should be appreciated that the controller <NUM> can alert an operator that the knife tray <NUM>, and carried knives <NUM>, has moved to the shielded position and allow an operator to signal for the actuator <NUM> to return the knife tray <NUM> to the exposed position.

From the foregoing, it should be appreciated that the overload protection assembly <NUM> provided according to the present disclosure can prevent excessive loads from being transmitted to the cutting unit <NUM> by retracting the knives <NUM>. Retracting the knives <NUM> can also make it easier to clear a blockage by increasing the amount of clearance that is available to allow passage of the blockage. The slide members <NUM>, <NUM> can be adjusted in a variety of ways to tailor the overload force that causes the first slide member <NUM> to slide relative to the second slide member <NUM> so the knife tray <NUM> moves to the shielded position where the knives <NUM> are not exposed to collected crop material. Further, the slide members <NUM>, <NUM> can be easily assembled together as castings and controlled by, for example, extension and retraction of the actuator <NUM> to move the knife tray <NUM> and the knives <NUM> back to the exposed position from the retracted position. Thus, the overload protection assembly <NUM> provides an elegant solution for reducing the risk of the cutting unit <NUM> being damaged while also being easily manufactured and assembled and convenient for returning the knife tray <NUM> to the exposed position.

Claim 1:
A cutting unit (<NUM>) for an agricultural baler (<NUM>), comprising:
a plurality of knives (<NUM>);
a knife guard (<NUM>) comprising at least one opening (<NUM>); and
a knife tray (<NUM>) carrying the knives (<NUM>), the knife tray (<NUM>) being movable between an exposed position where the knives (<NUM>) extend through the at least one opening (<NUM>) and a retracted position where the knives (<NUM>) are shielded by the knife guard (<NUM>);
an overload protection assembly (<NUM>) comprising a first slide member (<NUM>) coupled to the knife tray (<NUM>) and comprising a first engagement surface (<NUM>) and a second slide member (<NUM>) comprising a second engagement surface (<NUM>) that is engaged with the first engagement surface (<NUM>), the first slide member (<NUM>) and the second slide member (<NUM>) being held together and slidable relative to one another such that the first slide member (<NUM>) slides relative to the second slide member (<NUM>) to move the knife tray (<NUM>) from the exposed position to the retracted position when an overload force is applied to at least one of the knives (<NUM>)
characterized in that
the first slide member (<NUM>) or the second slide member (<NUM>) comprises a locking projection (<NUM>) on its engagement surface (<NUM>, <NUM>) and the other of the first slide member (<NUM>) and the second slide member (<NUM>) comprises a recess (<NUM>) holding at least a portion of the locking projection (<NUM>), and
wherein the locking projection (<NUM>) and the recess (<NUM>) are configured to come out of full engagement when the knife tray (<NUM>) moves from the exposed position to the retracted position.