Chopper arrangement for a forage harvester

A forage harvester chopper arrangement is located within a housing provided with an access door mounted for pivoting vertically between a chopping position, wherein access to the chopping arrangement is prevented, and a grinding position, permitting access to the chopping arrangement by a grinding arrangement. A locking arrangement is associated with the access door and an actuator is coupled to the access door and the locking arrangement by a linkage containing lost-motion means which operates such that when moving the access door to its grinding position, the locking arrangement is moved to its unlocked position prior to the access door being raised to its grinding position, and such that when returning the access door to its chopping position, the access door is closed before the locking arrangement is moved to its locked position.

FIELD OF THE INVENTION

The invention concerns a chopper arrangement for a forage harvester with a guide arrangement and a access door arranged on a housing at the chopper arrangement, that can be moved by means of an actuator actuated by external forces between a chopping position, in which it closes the housing, and a grinding position, in which it partially opens the housing, so that the grinding arrangement can interact with the chopper arrangement.

BACKGROUND OF THE INVENTION

In forage harvesters, it is useful to sharpen the knives of the chopper arrangement from time to time in order to assure that the knives are sufficiently sharp. In this way, the energy requirement for the chopping are kept low and the quality of the cut is kept high. The chopper arrangement is enclosed by a housing that is provided with openings for the supply and delivery of the harvested crop, but its otherwise closed, in order to prevent a discharge of the harvested crop at undesired locations and a contact of the chopper arrangement with the operator. In order to permit the grinding arrangement to interact with the chopper arrangement, the state of the art provides a access door that can be moved between a chopping position, in which it closes the housing in order to prevent an undesired access to the chopper arrangement, and a grinding position, in which it permits access to an opening in the housing, through which the chopper arrangement can interact with the grinding arrangement. In this position, a visual inspection of the knives and a possible replacement of the knives can also be performed.

The movement of the access door between the aforementioned positions can be performed by an actuator actuated by external forces, particularly an electric linear motor (DE 41 34 957 A) or a rotating electric motor (EP 0 444 916 A) that is connected so as to drive the access door over a drive mechanism. The position of the access door is detected by sensors, particularly limit switches or linear potentiometers, and the actuator is controlled to correspond. Thereby the access door is retained exclusively in the chopping position by the actuator.

In certain operating conditions, particularly if the harvested crop is not delivered properly at the outlet of the chopper arrangement and re-circulates with it or jams the chopper arrangement, relatively intense forces can be applied to the cover arrangement, that can also act in form of impulses or beats, and can be transmitted over the drive mechanism to the actuator and the sensor of the position detection arrangement of the cover arrangement. These forces can lead to damage of the actuator or the sensor.

The problem underlying the invention is seen in the need to overcome the aforementioned problem.

SUMMARY OF THE INVENTION

According to the present invention, there is provided an improved access door control arrangement for a chopper arrangement of a forage harvester.

An object of the invention is to provide such an access door control arrangement which includes a locking arrangement for securing the door in its chopping position.

This object is achieved by mounting the access door to the chopper housing by a locking arrangement which may be released from a locked position. The locking arrangement fixes the position of the door independently of any possible retaining force of the actuator, actuated by external forces. In this way, the result is that any possible forces acting on the door, that can be caused particularly by harvested crop jamming itself up, can be deflected by the locking arrangement and not transmitted to the actuator and, if necessary, to the sensor for the detection of the position of the access door or transmitted only to a lesser degree. Thereby damage to these elements need not be feared.

One solution is to use the actuator, actuated by external forces, that moves the access door also for the retaining and releasing of the locking arrangement. This is performed to great advantage, in which the actuator at first brings the locking arrangement into the release position for the opening of the access door and in a time sequence, subsequently moves the access door into the grinding position. Analogously, the access door is first moved into the chopping position and then the locking arrangement is secured.

In order to attain this operating procedure, a solution is to provide a connection between the actuator and the cover arrangement, that permits a certain lost-motion. If the actuator moves within this lost-motion, then it opens or closes the locking arrangement. Upon overcoming the lost-motion, the access door is moved. This can be attained by any desired mechanical device, for example, by an elongated hole that is engaged by a pin or by a cam that interacts with an opposing element. The drive arrangement between the actuator and the locking arrangement can be rigid or buffered by a spring.

In a preferred embodiment of the invention, the locking arrangement includes a locking bar element that moves in a linear direction in a corresponding guide ion order to avoid tilting. In the locking position, the locking bar element engages an associated opening. Here it does not matter whether the locking bar element is attached to the access door and engages an opening in the housing or inversely is attached to the housing and engages an opening in the cover arrangement. In another embodiment, the locking bar element performs a rotating movement.

Finally, the actuator, actuated by external forces, is connected with the access door and the locking arrangement preferably over a shaft. The actuator may be a linear motor that preferably drives the shaft by means of gears. The shaft pivots or rotates the access door between the chopping position and the grinding position and also moves the locking arrangement in a linear motion or in a rotary motion. In another embodiment, the actuator moves the access door in a linear direction.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A self-propelled harvester10, shown inFIG. 1, includes a frame12supported on front driven wheels14and rear steerable wheels16. The forage harvester10is controlled from an operator's cab18from which a harvested crop recovery arrangement20can be viewed. Crop, for example, corn, grass or the like, taken up from the ground by the crop recovery arrangement20is conducted to a chopper arrangement2in the form of a chopper drum, that chops the crop into small pieces and delivers these pieces to a conveyor arrangement24. The crop leaves the harvesting machine10to an accompanying trailer through a discharge duct26that can be rotated about a vertical axis and which may be repositioned in height. A post chopper reduction arrangement or kernel processor28, that can be removed if desired, is arranged between the copper arrangement2and the conveyor arrangement24, through which the crop to be conveyed is conducted tangentially to the conveyor arrangement24. The invention could also be applied to a towed or an attached forage harvester.

FIG. 2shows the attachment of the chopper arrangement22about whose circumference knife holders30are distributed with knives32, fastened by screws34, in a drum-shaped housing36that is approximately coaxial with the axis of rotation of the chopper arrangement22. A shear bar38is arranged at an inlet opening40of the housing36to which harvested crop is supplied by the harvested crop recovery arrangement20. The knives32cut the harvested crop in interaction with the shear bar38. Then the harvested crop reaches the post chopper reduction arrangement28through an outlet opening42of the housing36or, in case that the post chopper reduction arrangement has been removed, it reaches the conveyor arrangement24directly.

An access door44is located on the upper side of the housing36that can be pivoted between a chopping position, shown in solid lines, and a grinding position, shown in dashed lines, supported in bearings about an axis46extending parallel to the axis of rotation of the chopper arrangement22. The access door44encloses the housing36in the upward direction, so that no harvested crop can exit there and unintended contact with the knives32by an operator should not be feared. In the grinding position, the access door is pivoted upward and opens an opening48on the upper side of the chopper arrangement22.

The knives32of the chopper arrangement22can be examined visually by an operator through the opening48. Moreover, a grinding arrangement50can operate upon the knives32through the opening48when the access door44is in the grinding position, the grinding arrangement consisting of a carriage52with a grinding stone54arranged on its underside as well as guide elements56,58. In its rest position, the carriage52is located to the side alongside the chopper arrangement22, so that then pivoting of the access door44becomes possible without the danger of a collision with the grinding arrangement50. During the grinding, the carriage52with the grinding stone54is guided through means of the guide elements56,58, that extend parallel to the direction of rotation of the chopper arrangement22, along the width of the rotating chopper arrangement22, and preferably in the opposite direction to the direction of rotation use in the harvesting operation, that is shown inFIG. 2extending in a counterclockwise direction, it is guided along the rotating chopper arrangement22, in order to sharpen the knives32. The grinding process can be initiated by the operator or an appropriate sensor arrangement, that detects dull knives32(see DE 102 35 919 A and references cited therein). The details of the grinding arrangement50are disclosed by DE 199 10 757 A, whose disclosure is incorporated into the present application by reference.

It can be seen that the access door44must be brought into the grinding position before the grinding process, and it must be brought back into the chopping position for the resumption of the harvesting operation. The movement of the access door44is performed by means of an actuator60, actuated by external forces, and a mechanism, that is shown inFIG. 3. Thereby the grinding process can be initiated automatically or by the operator in the operator's cab18and be performed automatically without any need for the operator to leave the operator's cab18. Thereby, an electronic control arrangement64, shown schematically, controls the grinding arrangement50and also controls the actuator60, actuated by external forces, of the access door44in order to bring it into the grinding position before the grinding process and subsequently to bring it into the chopping position.

The actuator60is a linear motor, known in itself, that contains an electric motor62, whose rotary movement is converted into linear movement by appropriate elements, such as a rack that interacts with a gear driven by the electric motor62. The electric motor62is arranged in a housing66that is located to the side alongside the access door44with respect to the direction of operation of the forage harvester10, and the housing extends vertically. On its upper side, the housing66is connected directly or indirectly to the frame12of the forage harvester10. A drive rod68is located on the underside of the housing66and it can be moved in the vertical direction by the electric motor62. A sensor70is located in the housing66, or outside of it, and takes the form of a rotary or linear potentiometer that is arranged to detect the actual position of the drive rod68. The electric motor62and the sensor70are connected with the electronic control arrangement64which also controls the grinding arrangement50, as is shown schematically inFIG. 3. In place of an actuator60operating on a linear basis, a rotary actuator could also be used. In place of an electric drive, a pneumatic or hydraulic drive could also be used for the actuator60.

A lower region of the drive rod68is connected in a joint to a pivot lever76over a horizontal, transverse coupling pin72. The pivot lever76is fastened to a shaft78which extends parallel to the axis of rotation of the chopper arrangement22. The shaft78is supported in bearings at both ends, not shown, free to rotate, on the frame12about its longitudinal axis, which corresponds to the axis46. The elongated hole74and the coupling pin72permit a conversion of the linear movement of the drive rod68into a pivoting movement of the shaft78. For this purpose, any other desired devices could be used, such as a joint.

Furthermore, a rear side of the access door44is formed to define a pair of laterally spaced sleeves80and82received on the shaft78for free pivotal movement, whereby the access door44is mounted for pivoting vertically about the axis46. As shown inFIG. 4, the drive connection between the shaft78and the access door44is performed by an elongated hole connection, that provides an initial rotational lost-motion, in which the access door44is not yet moved. This lost-motion connection is composed of a lever84applied to the upper side of the shaft78, an upstanding bracket88joined to an upper surface of the door44at a location beside the lever84, with the bracket88containing an elongate hole86that extends vertically at a radius about the axis46, and a coupling pin90extending parallel to the axis46, which is carried by the lever84and is received within the elongated hole86.

Moreover, two levers92are fastened to the shaft78and are provided with openings at their outer ends through which coupling pins94extend which are attached to forks96and which extend parallel to the axis96. These openings are configured as elongated holes. The forks96are attached to rods98that extend forward and approximately in the horizontal direction. The rods98are connected with two rods102over joints100. The joints100can move about axes extending parallel to the axis46. The second rods102also extend forward and approximately in the horizontal direction. In the embodiment shown, the rods98can be adjusted in their length. But this characteristic is not an absolute requirement, and non-adjustable rods could also be used. The second rods102extend into cylindrical guides104that are fastened to the access door44, in whose opposite ends cylindrical locking bar elements106are supported in bearings which are coaxial to the guides104and the second rods102. As can be seen inFIG. 5, a preloaded helical spring108is arranged within each of the guides104and coupled between adjacent ends of the second rods102and the locking bar elements106, both of which are supported in bearings, free to slide. The springs endeavor to press the locking bar elements106away from the second rods102and to transmit rearward or forward movement of the second rods102to the locking bar elements106.

On the rear side of the part of the housing36that is located immediately in front of the access door44in the direction of operation, an angled border110is provided. Two cylindrical openings112are provided in the border, that extend coaxially to the locking bar elements106.

Thus, it will be appreciated that the actuator60is coupled to the access door44and the locking bar elements106by a linkage including the shaft78, the lever76coupled between the actuator60and the shaft78, the lever84coupled between the shaft78and the access door44, the levers92coupled between the shaft78and the first rods98, and the second rods102connected between the first rods98and the compression springs108, which are in turn, coupled to the locking bar elements106.

The following description of the method of operation begins with the fact that the actuator60, actuated by external forces, is located at first in its upper end position. Then the shaft78and the levers84,92coupled to it are located in the position shown inFIG. 3. The locking bar elements106penetrate the openings112in the border110of the part of the housing36ahead of the access door44. Thereby the access door is located in the chopping position and is locked by the locking bar elements106at the housing36. In case that harvested crop is unintentionally carried along around the chopper arrangement22or even jams it, so that relatively high radial and/or tangential forces are applied to the access door44, these forces are deflected by the locking bar elements106to the housing36and are not absorbed by the actuator60or only absorbed to a reduced degree. Damage to the actuator60or the sensor70is therefore not to be feared.

If the control arrangement64initiates a grinding process automatically or upon an operator input, the actuator60is activated. It moves the drive rod68downward, whose movement is transmitted over the coupling pin72to the pivot lever76. The latter performs a rotation of the shaft78, that is shown inFIG. 3as a clockwise movement. In view of the positions of the lever84, the elongate hole86and the coupling pin90, at first there is no movement that is transmitted to the bracket88and to the access door44, but only a movement of the coupling pin90relative to the elongate hole86. Thereby the access door44is not yet being raised.

On the other hand, the elongate openings in the levers92are so disposed relative to the coupling pins94that the rotation of the shaft78is immediately converted into a linear movement over the second levers92, the coupling pins94and the forks96, which is transmitted to the locking bar elements106over the first rods98, the joints100, the second rods102and the springs108. Thereby the locking bar elements106are moved to the rear, opposite to the direction of operation and withdrawn from the openings112. Thereby the locking arrangement formed by the elements cited in this section is released and the access door44is no longer locked to the part of the housing36located in front of it.

The positions of the lever84, the elongate hole86and the coupling pin90are selected in such a way that a transmission of the rotational movement of the shaft78to the bracket88and the access door44is performed only slightly after the locking of the locking bar elements106have been released from the openings112. Following this, the access door44is rotated upward against the force of gravity and to the rear into the grinding position. During this process, the position of the drive rod68is detected by the sensor70and continuously monitored by the control arrangement64. The latter causes the actuator60to be de-energized as soon as the access door44has reached the grinding position.

Now the grinding process or an inspection of the knives32by the operator can take place. Since the access door44is now in a definite position at a distance from the grinding arrangement50, there is the possibility of arranging sealing elements, not shown, at the extreme front face of the access door44, which are affected relatively little by the sparks generated during the grinding process. This makes possible an improved sealing about the access door44of the housing36when in the chopping position.

After the conclusion of the grinding process and the other operations, the access door44is again brought into the chopping position under the control of the control arrangement64. For this purpose, the actuator60is induced to raise the drive rod68. Then the shaft78, inFIG. 3, rotates in the counterclockwise direction. The access door44sinks downward and to the front under the force of gravity and/or the effect of the lever84on the coupling pin90, and finally reaches the chopping position. The elongate holes in the second levers92, which engage the coupling pins94, is dimensioned in such a way that the locking bar elements106extend to the front over the order of the access door44only when the chopping position has been reached, since the locking bar elements06could not previously enter into the openings12. The springs108prevent elements of the locking arrangement from being damaged when the openings112and the locking bar elements106are not aligned with each other for any reason whatever. But it would also be conceivable to omit the springs108. In this way, the locking bar elements106again extend into the openings112and the access door44is locked by the actuator60in the chopping position.