The present disclosure generally relates to an apparatus for supporting and/or directing crop in a harvesting machine. More particularly the disclosure relates to a shear bar or a stripper, comprising a one-part body with an axially extending recess in which a complementary hard material insert comprising an edge is or can be inserted.
Forage harvesters are agricultural harvesting machines that pick up crop from a field, chop it and transfer it to a transport vehicle via an ejection pipe. The crop can consist of plants such as corn or grain still standing on the field, or of already cut plants gathered into a swath, particularly grass, and is generally used as animal feed or for generating biogas. The cutting process takes place by means of a rotating chopper drum with a plurality of cutters distributed about its circumference, which cut the crop in cooperation with a shear bar.
The shear bar is subject to considerable wear in operation due to entrained sand particles in the crop, among other things, which is why the shear bar is typically provided with a wear-resistant coating, at least in the area of the longitudinal side serving as a cutting edge (cf. EP 1 264 535 A1). The service life of the materials that can be used for such a coating, and thus also the service life of the shear bar, is limited.
Shear bars with beveled corners have also been described, in which hard material inserts of tool steel are mounted by arc welding (cf. the prior art mentioned in EP 1 264 535 A1). In this regard, a sufficiently durable fixation of the hard material inserts, which must withstand the tangential cutting forces of the chopper drum, has proved to be problematic.
It has also been proposed to form an axial recess in the body of the shear bar, into which a mounting is bolted, which in turn has an axial groove into which are inserted wear-resistant inserts made of sintered hard metal that form the shear bar edge (see EP 0 761 089 A1). The hard material inserts are wedge-shaped with thicker ends at a distance from the shear bar edge and are fixed on the body of the shear bar by the bolts and the mount. This fixation of the hard material inserts is relatively expensive to produce due to the selected wedge shape of the hard material inserts and the mounting, and also requires that the bolts are always tight enough to keep the hard material inserts at their intended position.
Similar wear problems also exist for strippers, which are associated in forage harvesters with rollers in the intake duct or with post-cut devices. Strippers are also used in other harvesting machines, however, such as combines or balers.
The problem addressed by the invention is considered to be that of providing an apparatus for supporting and/or directing crop in a harvesting machine that does not have the above-mentioned disadvantages or has them to a reduced extent.
An apparatus for supporting and/or directing crop in a harvesting machine, particularly a shear bar for a forage harvester or a stripper, is composed of a one-part body with an axially extending recess and at least one complementary hard material insert, having an edge, and fitting into the recess. At least one surface of the recess is arranged such that a torque acting during operation on the hard material insert is transmitted by the hard material insert onto the body.
In this manner, the hard material insert is fixed and braced against the cutting forces (acting in the tangential direction of the cutters cooperating with the shear bar) and the torques induced by the cutting forces, (i.e. in the tangential and radial direction of the cutters for the chopper drum). The hard material insert in a stripper is analogously secured against the torque induced by the shearing force of the crop. An undesired movement of the hard material insert relative to the body need not be feared. The result is that the service life of the apparatus is extended.
The separate mounting that was still provided in the prior art according to EP 0 761 089 A1 is superfluous due to the one-part construction of the body.
In particular, the surface can enclose the hard material insert between said surface and a further surface of the body.
In one possible embodiment, the recess contacts at least three surfaces of the hard material insert in the mounted state. Alternatively, the hard material insert can have a protrusion with a triangular cross section.
In particular, the hard material insert and the body are or can be fixed to one another by an additional axially extending depression arranged in the recess and a protrusion that engages with it. The depression is preferably arranged in the body, while the protrusion is arranged on the hard material insert. A reverse attachment can also be conceived, however. Any other shapes of the depression such as a semicircular cross section, which additionally can comprise a flat surface, can also be conceived. In the concept of the present invention, the semicircular cross section implements a virtually infinite number of surfaces at which the hard material insert and the body contact one another.
The depression and the protrusion preferably have an at least approximately rectangular cross section, although triangular and any other cross sections are possible.
In addition, the depression and the protrusion extend parallel to the upper side of the body or at an angle of 45° downward therefrom. The cutting or shearing forces then press the protrusion into the recess (or vice versa) and interlock the hard material insert in the body. The resistance to the tangential cutting forces is further increased by an upward-directed angular shape of the depression and the protrusion. It goes without saying that angles other than 45° are also possible.
In one possible embodiment, a plurality of hard material inserts are arranged one after another in the axial direction and have complementary end sections engaging with one another. The edge is therefore composed of a plurality of segments arranged one after another in the axial direction, which are fixed to one another relative to the chopper drum or roller by the end sections in a tangential and/or radial direction (i.e. in the radial plane of the chopper drum or roller) and in the axial direction, in order to avoid undesired shifting or other movements of the hard material inserts relative to the body.
The hard material insert can additionally form a non-axial edge, which can be sawtooth-shaped or corrugated, inclined or equipped with depressions (cf. EP 0 022 053 A1). Because the chopper drum interacting with the shear bar is cylindrical in design, as in the prior art, the edge in this embodiment must follow the cylinder three-dimensionally in order to achieve a constant cutting gap over the length of the shear bar. Because the shear bar is not arranged axially, but at an angle to the axial line, the cutting process is free from distortion with an unchanged cylindrical chopper drum geometry because larger cutting angles become possible, which has a positive effect on the cutting forces and the service life as well as the noise emission. The cutting frequency and the noise spectrum that arise can even be modified and optimized by the different angles of the shear bar across the width of the chopper drum. In addition, the problem of conveying the chopping material axially toward the center of the drum, which was observed in the prior art with straight shear bars and cutters on the chopper drum arranged at an angle, can be avoided or reduced if the inclination of the slanted sections of the shear bar is oriented to the outside.
The hard material insert consists in particular of sintered or cast hard metal. The hard material inserts with a non-axial edge described in the previous paragraph can also be produced without problems with this manufacturing method.
Other features and aspects will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Further embodiments of the invention may include any combination of features from one or more dependent claims, and such features may be incorporated, collectively or separately, into any independent claim.
Between the crop receiving device 20 and the chopping drum 22, the material is transported by an intake conveyor with lower intake rollers 30, 32 and upper intake rollers 34, 36, which are mounted inside an intake housing 50. The lower intake rollers 30, 32 and the upper intake rollers 34, 36 are also referred to as pre-pressing rollers, because the upper intake rollers 34, 36 are pre-tensioned against the lower intake rollers 30, 32 by hydraulic and/or spring force, so that the crop is pre-compressed between the lower intake rollers 30, 32 and the upper intake rollers 34, 36 and can be cut better. Directional indications such as front and back refer below to the forward direction V of the forage harvester 10, which runs from right to left in
One hard material insert 64 that is complementary-fitting and axially extending is arranged in each of the recesses 58 and comprises a protrusion 66 that is axially extending and rectangular and extends into the depression 62. The cross section of the recesses 58 with the depressions 62 is accordingly L-shaped, which also applies to the cross section of the hard material insert 64 with the protrusion 66. The hard material insert 64 is fixed to the one-part body 56, for example screwed on, glued and/or welded at the upper transitions. The faces of the hard material insert 64 and the one-part body 56 that face one another need not be flat as shown in
The hard material insert 64 with the protrusion 66 drawn on the right side is enclosed on four surfaces by the surrounding recess 58 with the depressions 62, namely from below on the underside, from the right at the surfaces of the actual hard material insert 64 and the protrusion 66 from the right (i.e. in the radial direction of the chopping drum 22), and from the top at the upper side of the protrusion 66 (i.e. in the tangential direction of the chopping drum 22).
If the hard material insert 64 drawn on the left in
In the second embodiment, as seen in
In order to absorb the forces arising opposite to the cutting direction, which can appear for example during a displacement of the shear bar 38 based on a contact, the one-part body 56 and the hard material insert 64 can be provided according to
In the embodiment according to
In the embodiment according to
The plan view of the shear bar 38 shown in
The edges 54 form a sawtooth shape in the embodiment according to
In the embodiment according to
For the non-axially oriented edges 54 of
The present invention is not only for use with shear bars 38, but also for strippers 74 that can be associated with the rollers 28 of the post-cut device (cf.
While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
Various features are set forth in the following claims.
Number | Date | Country | Kind |
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102013211829.5 | Jun 2013 | DE | national |