Density system bypass for a round baler

An improved belt tensioning system for an agricultural round baler that temporarily bypasses a bale density, belt tension increasing system while the baler tailgate is moved out of a closed position thereby allowing the tailgate to be opened without encountering resistance form the belts and the belt tensioning system. Bypass operation is coordinated with the tailgate position so that the bypass is not activated when such activation would frustrate operation of the belt tensioning system. In balers equipped with a belt tensioning pre-tensioning system, the bypass operation is further coordinated with the pre-tensioning system to maintain proper pre-tension function.

BACKGROUND OF THE INVENTION

The present invention relates generally to agricultural round balers which form cylindrical bales using one or more movable belts and/or rollers disposed in a bale-forming chamber and, more particularly to an improved system for tensioning the movable belts.

Round balers have become quite prevalent for their capability of producing a conveniently sized cylindrical bale, very often automatically wrapped with a sheeting material such as net or film. Crop material, such as hay, is picked up from the ground as the baler travels across the field, and is fed into an expandable chamber where it is rolled up to form a compact cylindrical hay package.

Prior art round balers generally have an expandable bale chamber defined by a pair of fixed sidewalls, and a plurality of side-by-side belts cooperating with a series of transverse rolls, mounted between a pair of pivotally mounted arms commonly known as a sledge. The chamber includes an inlet opening in the front through which crop material is fed. Also included is a pair of take up arms pivotally mounted on the main frame, between which arms multiple of guide rolls are journalled. A biasing force is applied on the take up arms to urge the outer surfaces of the guide rolls against the belts to maintain belt tension and prevent slack from occurring in the belts during expansion and contraction of the chamber.

It is known to provide a round baler density system to apply increased tension on the belts in order to create a densely packed bale. A hydraulic density cylinder with a controlled fluid release limits the rate of bale chamber expansion and provides a degree of crop compaction during baling. The amount of compaction may be varied by adjusting the fluid release rate, often in the form of a pressure relief valve which restricts the extension of the density cylinder by forcing fluid through a variable relief. When the bale reaches a desired size and is discharged, mechanical springs acting on the take up arms are typically employed to return the hydraulic cylinder to its initial position and provide a biasing force on the take up arms so a new bale forming cycle may commence.

Problems arise as the tailgate is opened in preparation to discharge the completed bale. The geometry of the belt take-up system requires some slack in order to open the tailgate and discharge the bale. If the density system is resisting slackening movement of the belts during tailgate opening, the tailgate opening apparatus must overcome not only the force necessary to lift the tailgate, but the resistive force applied to further extension of the belt take-up mechanism. This results in increased power input required during the tailgate opening sequence, and skewing of the tailgate and belts.

It would be desirable to provide a system that would release the resistive force applied on the belts by the bale density system when the tailgate is released for opening. Additional advantages would be realized by a system that would automatically release the resistive force based on positioning of the tailgate latching system and restore the bale density to a normal operation configuration once the tailgate is fully opened or begins to close. Still further advantages would be realized by a density system release mechanism that could be easily incorporated into existing baler density systems with minimal alteration of the existing bale density tensioning system.

SUMMARY OF THE INVENTION

Accordingly, the present invention, in any of the embodiments described herein, may provide one or more of the following advantages:

It is an object of the present invention to provide an improved bale tensioning system for an agricultural round baler that includes an automatic bypass feature for disengaging the bale tensioner system during tailgate opening.

It is a further object of the present invention to provide an improved agricultural round baler belt tensioning system having a closed-loop hydraulic tensioner apparatus with a hydraulic bypass loop that may be selectively opened upon an input signal from a tailgate opening system on the baler.

It is a further object of the present invention to provide an improved hydraulic belt tensioning system with a bypass arrangement for an agricultural round baler that enables efficient tailgate operation without imposing additional opening loads or increasing tailgate stresses due to forces generated by the belt tensioning system.

It is a further object of the present invention to provide an improved hydraulic bale density system with an automatic, selective bypass for an agricultural round baler that is easily retrofitted onto existing round balers having bale density systems.

It is a still further object of the present invention to provide an improved hydraulic bale density system for an agricultural round baler, the density system having an automatic bypass that is durable in construction, inexpensive of manufacture, carefree of maintenance, easily assembled, and simple and effective to use.

These and other objects are achieved according to the instant invention by providing an improved belt tensioning system for an agricultural round baler that allows temporarily bypasses a bale density, belt tension increasing system while the baler tailgate is moved out of a closed position thereby allowing the tailgate to be opened without encountering resistance from the belts and the belt tensioning system. Bypass operation is coordinated with the tailgate position so that the bypass is not activated when such activation would frustrate operation of the belt tensioning system. In balers equipped with a belt tensioning pre-tensioning system, the bypass operation is further coordinated with the pre-tensioning system to maintain proper pre-tension function.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art, and they will not therefore be discussed in significant detail. Also, any reference herein to the terms “left” or “right” are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel. Likewise, “forward” and “rearward” are determined by the normal direction of travel. “Upward” and “downward” orientations are relative to the ground or operating surface as are any references to “horizontal” or “vertical” planes. Furthermore, the various components shown or described herein for any specific application of this invention can be varied or altered as anticipated by this invention and the practice of a specific application of any element may already be widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. When referring to the figures, like parts are numbered the same in all of the figures.

Referring to the figures, a generally well-known round baler10which incorporates the preferred embodiment of the present invention, includes a main frame11supported by a pair of wheels14(only one shown). A tongue12is provided for connection to a tractor. Pivotally connected to the sides of main frame11is tailgate13which may be closed (as shown inFIG. 1) during bale formation or pivoted open by tailgate actuator19to discharge a completed bale. A conventional pickup16, mounted on main frame11, includes a plurality of tines17movable in a predetermined path to lift crop material from the ground and deliver it rearwardly toward a rotatably mounted floor roll18.

A chamber20for forming bales is defined partly by a sledge assembly30comprising a plurality of rollers31,32extending transversely in the arcuate arrangement shown inFIGS. 2 and 3. Rollers31,32are journalled at their ends in a pair of spaced apart arms35, one of which is shown. These arms are pivotally mounted inside main frame11on stub shafts for providing movement of sledge assembly30between the bale starting position shown inFIG. 2and the full bale position shown inFIG. 3. Rollers31,32are driven in a clockwise direction by conventional means (i.e., chains and sprockets or gears) connected to and powered by a prime mover via a drive shaft15. A freely rotatable idler roller33is also carried by arms35. Additionally, a starter roll37, and a fixed roll38are located adjacent to roller31, and are also driven in a clockwise direction by the conventional means.

The bale forming chamber is further defined by an apron40comprising a plurality of continuous side-by-side belts supported by guide rolls43,44,45,46,47rotatably mounted in tailgate13and a drive roll48, mounted on main frame11. Apron40passes between roller32on sledge assembly30and idler roller33, and is in engagement only with idler roller33and not roller32which is located in close proximity to the apron belts to strip crop material from the belts, in addition to its bale forming function. Drive roll48is powered via a power take-off from the tractor and a drive train (not shown) which moves apron40along its changing path, indicated generally by arrows A and B inFIGS. 2 and 3. An additional guide roll49ensures proper driving engagement between apron40and drive roll48.

A pair of take up arms51(only one shown) are mounted to pivot conjointly with a cross shaft52between inner and outer positions, shown inFIGS. 2 and 3, respectively, and carry additional guide rolls53,54for supporting apron40. Belt tension lever arm55is also affixed to shaft52to pivot with take up arms51. A return spring60is secured between the baler chassis11and tension lever arm55to bias the shaft52and take up arms51toward the bale starting position (shown inFIG. 2) and move the take up arms toward the bale starting position following ejection of a completed bale. A hydraulic bale tension cylinder56is mounted between tailgate13and take up arms51and configured to resist movement of the take up arms from the bale starting position (FIG. 2) toward the full bale position (FIG. 3).

Rounds balers including belt take-up and tensioning apparatus of the aforementioned type are well known in the art. Exemplar take-up apparatus are described in U.S. Pat. Nos. 4,870,812 and 5,367,865, both to Jennings et al., each being incorporated herein by reference.

FIG. 4shows the baler10with tailgate13in the raised or open position as would be necessary to eject a completed bale from the bale forming chamber20. The relationship of the tailgate13, apron40and its rolls, and take up arms51is such that additional extension of bale tension cylinder56beyond that required for a full bale is necessary to raise the tail gate to an open position as shown inFIG. 4. The normal resistance to extension that tension cylinder56applies to take up arms51thus creates resistance to opening of the tailgate.

Now turning toFIGS. 5 through 7to describe in further detail the tensioning system100bypass arrangement at the heart of the present invention. The elements are shown as the bale formation is in progress inFIG. 5, as the bale has reached a fully-formed diameter and the tailgate is being opened inFIG. 6, and as the tailgate is being closed and the bale chamber returns to the empty, ready to begin bale formation position inFIG. 7.

Apron tensioning system100comprises a closed hydraulic loop including the hydraulic tension cylinder56acting on the take up arms51via belt tension lever arms55. The apron tensioning system is hydraulically separate from the active hydraulic system used to open and close the tailgate13using tailgate actuator19. The hydraulic system includes hoses107supplying fluid to both high-side101(rod end) and low-side103(base end) sides of a piston561mounted on a rod562in cylinder56, an adjustable relief valve104with a return free flow check valve102. A pre-tension accumulator reservoir110, if included, is connected to the hose107by a solenoid-operated check valve108that allows selective reverse flow through the valve. The accumulator reservoir110is preferably a conventional gas-charged hydraulic accumulator with provisions for altering the gas pressure. A pressure indicator120is provided to allow an operator to adjust the relief valve104by an adjuster105to a desired pressure in the system100corresponding to a desired density of the resultant bales. A bypass valve120is provided in parallel around the high-side101and low-side103of the tension cylinder. In one embodiment, bypass valve is a two-way solenoid valve offering an open port in the first position and a check valve in the second position, similar to the solenoid-operated check valve108. The check valve is arranged to provide a return flow path in parallel with return free flow check valve102. Alternatively, the bypass valve120could be provided with a simpler open flow port and a closed port corresponding to the two positions.

InFIG. 5, hydraulic fluid is forced from the high-side connection101into hoses107as the tension cylinder is extended in the direction of arrow E and the bale forms in the bale chamber. As the bale expands, tension cylinder56continues extending in the direction of arrow E, continuing to force fluid into the system from the high-side101connection increasing pressure therein. Hydraulic pressure in system100increases to the selected pressure setting of relief valve104which then allows fluid to pass from the high side101to the low-side103connection of the tension cylinder56. This continues until the bale reaches the desired size.

FIG. 6shows the baler as it prepares to eject the bale. Tailgate lift cylinder19is activated by tailgate control valve124to extend the cylinder19and open the tailgate. A control module125coordinates control signals to the bypass valve120and tailgate control valve124so that the bypass valve120is shifted to the bypass position when the tailgate as the tailgate is opened, allowing fluid to move freely from the high side101to the low side103of tension cylinder56, avoiding the restriction normally created by flow through the relief valve104. Control logic for the bypass valve120also prevents the opening of solenoid-operated check valve108on systems equipped with a pre-tension apparatus to prevent blow down of the accumulator reservoir110to the low side103of tension cylinder56.

Referring toFIG. 7, return spring60returns the belt tension lever arms55to the empty, or bale initiating position, and retracts tension cylinder56in the direction of arrow R after the bale is discharged and the tailgate is closed. Hydraulic fluid pressure is now higher on the base end103than the rod end101. Return check valve102allows fluid to pass from the higher pressure base end103to the lower pressure rod end101(oil flow arrows0) so that the tension cylinder56may be retracted. Control logic in the control module125takes inputs from the positioning of the tailgate control valve124and the tailgate position to determine the timing of bypass valve120re-positioning. In systems equipped with a pre-tensioning booster system (e.g., accumulator110and solenoid operated check valve108), the bypass valve120must be repositioned prior to opening of the check valve108to prevent the accumulator charge pressure from being directed to extend the tension cylinder.