Drive arrangement for driving a cutter bar of a cutting mechanism

A drive arrangement for the reciprocating drive of a cutter bar comprises an input element which can be set into a continuous pivoting movement by a drive device, and an output element which is coupled to the cutter bar and is coupled to the input element by a coupling rod. The output element is pivotably connected to a first end of a first lever and of a second lever, which levers, for their part, are pivotably mounted. The levers and the output element are dimensioned in such a manner that the output element essentially only carries out a lateral movement.

FIELD OF THE INVENTION

The invention relates to a drive arrangement for the reciprocating drive of a cutter bar which is mounted displaceably in a plane in a lateral direction, with an output element which is coupled to the cutter bar and can be set into a lateral reciprocating motion by a drive device.

BACKGROUND OF THE INVENTION

Cutting mechanisms are used in the harvesting of agriculturally cultivated plants in order to cut the plants, bring them together and feed them to a harvesting machine in which they are processed further, in particular threshed (combine harvester) or chopped (field chopper). Cutting mechanisms of this type generally comprise a front cutter bar in order to cut the plants, a reel which is arranged above the cutter bar, in order to gather the upper parts of the plants to the rear, and a transverse conveyor worm which brings the crop together laterally in order to feed same through a rear opening in a rear wall of the cutting mechanism to a feeder housing of the combine harvester or to feed the crop to a drawing-in channel of the field chopper to produce whole plant silage. Side walls between which the cutter bar and the transverse conveyor worm extend are provided at the lateral ends of the cutting mechanism. The base of the cutting mechanism between the cutter bar and the rear wall is formed by a bottom plate referred to as a cutting table.

For adaptation to different types of crop and therefore plant sizes, cutting mechanisms with length-adjustable cutting tables are used. In particular for harvesting rape, the cutting table is extended forward (and supplemented by side blades), whereas, by contrast, said cutting table is retracted to the rear when harvesting lower plants or plants which unlike rape form a tight bush, such as, for example, wheat.

In particular in the case of cutting mechanisms with length-adjustable cutting tables, but also in the case of cutting mechanisms which are not length-adjustable, the drive of the cutter bar has proven relatively complicated since the driving torque from the combine harvester has to be transmitted entirely to the front to the cutter bar. In the prior art, the drive of the cutter bar customarily takes place by means of a driving belt which is arranged at a lateral end of the cutting mechanism and transfers the driving torque provided by the combine harvester forward to a gearing which, by means of an eccentric drive, converts the rotational movement into a linear reciprocating movement of the cutter bar (cf. DE 10 2004 037 580 A1 for a rigid cutting mechanism or EP 1 653 122 A1 for a cutting mechanism with a length-adjustable table), or the driving belt is replaced by a telescopic propeller shaft (EP 2 700 294 A2).

In the case of cutting mechanism widths of relatively large working widths, it is expedient to divide the cutter bar into two parts which are driven in counter phase in order to eliminate the vibrations caused by the reciprocating movement of the cutter bar. The drive here of the cutter bar halves of each end of the cutting mechanism can take place here by means of an associated gearing, the outputs of which are phase-displaced in relation to each other by 180° (U.S. Pat. No. 3,577,716 A), or, starting from the center of the cutting mechanism, by means of a gearing with a crankshaft which drives two phase-offset outputs (U.S. Pat. No. 5,497,605 A). Other drives arranged in the center of the cutting mechanism use eccentric drives driven via planetary gearings for converting the rotational movement of a hydraulic motor into the lateral movement of the cutter bar halves (EP 2 382 852 A2), or a gearing which is arranged on the rear wall of the cutting mechanism and converts the incoming rotational movement into a linear movement of a drive rod, said linear movement being directed forward and rearward in an alternating manner and being converted into a lateral movement by single-part angle levers (cf. DE 10 2010 040 870 A1 which is considered as forming the generic type).

In particular (but not only) in the case of cutting mechanisms with length-adjustable cutting tables, in the center of the cutting mechanism only a relatively limited vertical space is available in which a gearing for converting the incoming rotational movement into a lateral movement of the cutter bar halves can be installed. However, the crankshaft of U.S. Pat. No. 5,497,605 A requires a relatively large vertical construction space, and this is also true for the combined planetary and eccentric drives arranged one above the other of EP 2 382 852 A2, while the arrangement according to DE 10 2010 040 870 A1 has the disadvantage that the coupling points at which the cutter bar halves are attached to the angle levers not only move to the side, but also to a certain extent forward and rearward since they pivot to and fro about the rotational axes of the angle levers. This movement forward and rearward requires an undesirable wear-promoting play in the bearings for the lateral guidance of the cutter bars. If the mentioned cutter bar movement taking place forward and rearward is intended to be limited, the angle levers have to have a very long design, which makes the drive relatively large and heavy.

An object of the invention is to provide a drive arrangement for driving a cutter bar with gearing for converting the incoming rotational movement into a lateral movement of the cutter bar which is thin in the vertical direction and also does not have the disadvantages mentioned with regard to DE 10 2010 040 870 A1, or has said disadvantages to a lesser extent.

SUMMARY

A drive arrangement for the reciprocating drive of a cutter bar which extends in a plane in which said cutter bar is mounted displaceably in a lateral direction comprises an output element which is coupled to the cutter bar and can be set into a lateral reciprocating movement by a drive device. The output element is in each case pivotably connected to a first end of a first lever and to a first end of a second lever, which levers are in each case mounted pivotably at their second end. The levers and the output element are dimensioned in such a manner that the output element essentially only carries out a lateral movement.

In other words, a driven output element which is coupled to the cutter bar and moves in a reciprocating manner in the lateral direction during operation is supported by two levers in such a manner that said output element can at least approximately only move laterally during a movement by the coupling rod. In particular, the levers together with the output element can form an approximate Roberts straight-line mechanism. This has the effect that the output element carries out an almost perfect linear movement with simple and mechanical means of very thin construction.

The drive of the output element can be a linear drive (e.g. hydraulic cylinder) which acts directly on the output element. In another embodiment, an input element can be mounted pivotably about a first axis and can be set into a continuous pivoting movement about the first axis by means of a drive and can be coupled to the output element by a coupling rod. The continuous pivoting movement can be produced in a manner known per se by an eccentric drive which is driven in a rotational manner on the input side.

The coupling rod can be coupled to the input element and to the output element at a distance from the first axis about axes extending perpendicular to the plane of the cutter bar.

The first ends of the first lever and the first ends of the second lever can be mounted pivotably on the output element about second axes extending perpendicular to the plane of the cutter bar and can be mounted pivotably about third axes running parallel to the second axes.

The third axes can be arranged offset outward in front of the second axes and laterally in relation to the second axes.

On the front side of the cutting mechanism equipped with the drive arrangement according to the invention, two cutter bars which are driveable in opposite directions to each other by a respective drive arrangement can be arranged offset laterally with respect to each other on the front side. However, it would also be conceivable for the cutting mechanism, in particular in the case of smaller working widths, to be provided only with a single cutter bar and a single drive arrangement. However, said cutting mechanism could analogously also have three, four or more cutter bars which are driven in particular in a phase-offset manner by one drive arrangement each.

In particular, the coupling rod of a first drive arrangement for driving a first cutter bar can be coupled to the input element in front of the first axis, and the coupling rod of a second drive arrangement for driving a second cutter bar can be coupled to the input element rearward of the first axis.

The present drive arrangement is suitable in particular for cutting mechanisms with length-adjustable cutting tables in which a front cutting mechanism part is arranged adjustably in relation to a rearward cutting mechanism part. In the case of such cutting mechanisms, the drive arrangement and the cutter bar are supported on the front cutting mechanism part.

The cutting mechanism can be used on any self-propelling harvesting machines, such as combine harvesters or field choppers.

DETAILED DESCRIPTION

FIG. 1shows a self-propelled harvesting machine10in the form of a combine harvester in a top view. The harvesting machine10comprises a body12which is supported on driveable front wheels14and steerable rear wheels16and, in the harvesting mode, is moved over a field in a forward direction V which extends to the left inFIG. 1. At its front end, the body12bears a feeder housing18, to the front end of which in turn a cutting unit20is removably attached. The feeder housing18has a driven power take-off22to which an input shaft24for driving driven components of the cutting mechanism10is removably connected. In the harvesting mode, the cutting mechanism20cuts crop from a field, picks said crop up and feeds it to the feeder housing18which conveys said crop into the interior of the body12where the crop is threshed, separated and cleaned. Finally, the clean grain is deposited in a grain tank from which the grain can be transferred to a transport vehicle.

The cutting mechanism20is extendable and comprises a rearward part26with side walls30and with a transversely extending frame28which is attached to the feeder housing18, and a front part32with a baseplate34and two cutter bars36and42, here shown as reciprocating knives. The front part32with the baseplate34and the cutter bars36,42can be displaced in the forward direction “V” to the rear and front in relation to the rearward part26by hydraulic actuators (not shown). The rearward part26furthermore comprises a transverse conveyor worm40and a reel (not shown). Since adjustment mechanisms of the cutting mechanism are known per se (cf. DE 10 2013 208 957 A1, U.S. Pat. No. 7,082,742 B2 and U.S. Pat. No. 7,730,702 B2), a more detailed discussion is abstained from here.

The drive of the transverse conveyor worm40and optionally of the reel takes place via the input shaft24which extends transversely on the rear side of the cutting mechanism20and extends outward as far as the left side wall20. Also coupled to the input shaft24is a gearing44which is arranged adjacent to the power take-off22and is driven by the input shaft24(which extends through the housing of the gearing44) and serves for driving the cutter bars36,42. The gearing44is connected via a telescopic shaft46to an angular gearing48which, for its part, drives a transverse shaft50which, via a further angular gearing (not shown), drives a drive wheel52rotating about a central axis54. The angular gearing48, the further angular gearing and the drive wheel52are attached below the baseplate34and are directly or indirectly supported thereon, while the gearing44is fastened to the frame28of the rearward part26. The telescopic shaft46permits the relative movement between the gearing44and the angular gearing48that arises during the extension of the cutting mechanism20. In another embodiment, the drive wheel52could also be driven by the gearing44via a belt which is guided in a horizontal plane and is kept at a constant tension by two deflecting wheels, even when the cutting mechanism is extended, as is known per se (EP 2 769 610 A1), or an electric or hydraulic motor or hydraulic cylinder is used for this purpose.

The drive wheel52which is arranged rotatably about the axis54oriented perpendicularly to the plane of the baseplate34(and to the plane of the cutter bars36,42, in which plane said cutter bars also move in a reciprocating manner laterally) supports a pin56which engages in a slot in a fork-shaped element58which, for its part, is rigidly connected to an input element (shown here as lever60) of two drive arrangements for the reciprocating drive of the cutter bars36,42, or is produced integrally with said input element. Instead of a slot, the fork-shaped element58could also have an elongate hole. It would also be conceivable to mount the input element60on the eccentric pin56in a rotatable manner about an axis running parallel to the axis54, and therefore the displacement movement between the fork-shaped element58and the pin56is omitted, and the input element60can be configured to be telescopic or extendable in some other way between the pin56and the coupling point of the second coupling rod62. An eccentric could also be mounted on the pin56in a rotatable manner about an axis running parallel to the axis54and could connect said eccentric to the input element60via a coupling joint. An eccentric could also be mounted on the pin56in a rotatable manner about an axis running parallel to the axis54and the rotational movement of said eccentric could be transmitted to the input element60via a displaceably mounted element. Accordingly, the input element can be set in any desired way into a continuous pivoting movement about the axis78.

The input element60is coupled pivotably in the vicinity of its front end in relation to the baseplate34about the first axis78, which runs parallel to the axis54, to which end reference is now made toFIG. 3.

A first rectilinear coupling rod64is coupled to the front end of the input element60pivotably about an axis88running parallel to the axis54and is coupled to a first output element68pivotably about an axis90running parallel to the axis54(and approximately centrally in the forward direction V), said output element, for its part, being coupled to the left cutter bar42pivotably about the vertical axis (or an axis running parallel to the axis54) or rigidly (directly or via connecting elements arranged inbetween). The coupling rod64extends to the left transversely with respect to the forward direction V. A first lever74is connected to a rearward end of the Y-shaped output element68pivotably about an axis82running parallel to the axis54and at the other end is mounted pivotably in relation to the baseplate34about an axis86running parallel to the axis54. The first lever74extends forward and to the right from the axis82. A second lever76is connected to the other rearward end of the output element68pivotably about an axis80running parallel to the axis54and at the other end is mounted pivotably in relation to the baseplate34about an axis84running parallel to the axis54. The second lever76extends forward and to the left from the axis80. The two levers74,76are identical in length and are arranged symmetrically with respect to each other about the longitudinal axis of the output element68.

A second angled coupling rod62is coupled to the rear of the axis78to the input element60pivotably about an axis102running parallel to the axis54(seeFIG. 2) and is coupled pivotably to a second output element66about an axis100which runs parallel to the axis54and is located in the forward direction V at the same height of the axis90(and approximately centrally on the output element66in the forward direction V), said output element, for its part, being coupled to the right cutter bar36pivotably about the vertical axis (or an axis running parallel to the axis54) or rigidly (directly or indirectly via connecting elements arranged inbetween). The distance between the axes78and102is preferably identical to the distance between the axes78and88. A third lever70is connected to a rearward end of the Y-shaped output element66pivotably about an axis92running parallel to the axis54and at the other end is mounted pivotably in relation to the baseplate34about an axis98running parallel to the axis54. A fourth lever72is connected to the other rearward end of the output element66pivotably about an axis94running parallel to the axis54and at the other end is mounted pivotably in relation to the baseplate34about an axis96running parallel to the axis54.

The axes54,78,84,86,96and98can be fastened to the baseplate34or to any other holding element which, for its part, is fastened to the front part32. The axes88,102,90,82,80,94,92and100connect only two movable components in each case to each other and are not fastened directly to the baseplate34or to the mentioned holding element holding the axes54,78,84,86,96and98. As illustrated inFIG. 2, the output elements66,68can be triangular or, as shown inFIG. 3, Y-shaped. The third lever70extends to the front and right from the axis92. The fourth lever72extends to the front and left from the axis94. The two levers70,72are identical in length and are arranged symmetrically with respect to each other about the longitudinal axis of the output element66. The drive arrangements are located below the baseplate34and can be downwardly protected by means of a covering. The cutter bars36and42are mounted in a laterally displaceable manner on the front part42at a distance from the output elements66,68, for which purpose use can be made of linear bearings which are known per se, or further arrangements according toFIG. 3which, however, are not actively driven.

In light of the foregoing, during operation, the drive wheel52rotates about the axis54, in a manner driven via the power take-off22, the input shaft24, the gearing44, the angular gearing48and the further angular gearing which is not shown inFIG. 2. The pin56converts the rotational movement, in interaction with the slot in the fork-shaped element58, into a reciprocating pivoting movement of the input element60about the first axis78. The dimensions of the output elements66,68and of the levers70to76and the position of the axes54,78,84,86,96,98,88,102,90,82,80,94,92and100are selected in such a manner that the movement of the output elements66,68over the range of movement which occurs during operation, of the input element60takes place (virtually) exclusively in the lateral direction. The coupling rods62,64and the output elements66,68and the levers70to76therefore form drive arrangements which convert the reciprocating pivoting movement of the input element60into a (virtually) pure linear movement of the cutter bars36,42without a great mechanical outlay and with a very flat construction. The central drive also affords the advantage that the side walls of the cutting mechanism can be of a more slender construction because of the omission of the lateral drive of the cutter bar, and contact of the crop with housings arranged at the cutting mechanism ends and losses resulting therefrom are avoided. The transmission ratio and the position for the drive unit can be adapted and optimized via the lever length and geometry of lever60. The drive arrangements here are designed as what are referred to as a Roberts straight-line mechanism.