Forage Harvester

A forage harvester cracker unit comprising a first cracker roller, a second cracker roller, a base frame comprising left and right hand side elements, the first cracker roller being mounted on the base frame to be rotatable about a fixed central axis extending between the left and right hand side elements of the base frame and a secondary frame comprising left and right hand side elements, the second cracker roller being mounted on the secondary frame to be rotatable about a central axis extending between the left and right hand side elements of the secondary frame is disclosed. The forage harvester cracker unit further comprises a pivot axis extending through the base frame and the secondary frame, the secondary frame being adjustable about the pivot axis to enable variation of a separation of the first and second cracker rollers, a biasing element acting between the base frame and the secondary frame to urge the second cracker roller towards the first cracker roller and a drive element acting against the biasing element to hold the secondary frame in position against the biasing element to maintain a minimum separation of the first and second cracker rollers.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

FIELD

The present invention relates to an improved forage harvester, and, in particular, to a cracker unit for a forage harvester.

BACKGROUND

It is known to provide forage harvesters with a cracker unit. The cracker unit includes opposing cracker rollers through which harvested crop is fed. The harvested crop is first fed though a chopper unit and then into the cracker unit where it is squeezed and crushed between the opposing cracker rollers before being fed to a discharge spout.

The cracker unit includes a first cracker roller, that is free to rotate, and can be driven about its longitudinal axis and is supported in bearings on a first frame element. The first cracker roller is located toward a first end of the cracker unit. A second cracker roller is provided. In a known construction, the second cracker roller is driven and supported in bearings on a second frame element. The second frame element is located to a second end of the cracker unit and can be linearly adjusted with respect to the first frame in order to adjust a spacing between the first and second cracker rollers. Together the first and second cracker rollers provide an elongate opening between left and right hand sides of the cracker unit through which harvested crop that is to be processed can be conveyed. The first frame element serves as a base of the cracker unit. Additional first and second covering elements are secured to the first frame element to form an upper housing of the cracker unit through which processed crop is directed towards the discharge spout.

A pre-loading arrangement is provided on the second frame element such that the second cracker roller is preloaded towards the first cracker roller. Further, the spacing between the cracker rollers is adjustable by means of a linear adjustment apparatus in which the second frame element sits on a slide to adjust the position of the axis of rotation of the moveable second cracker roller with respect to that of the first cracker roller.

The present invention provides an alternate mounting arrangement that enables adjustment of the moveable cracker roller with respect to its fixed counterpart. Other advantages of the present invention will be apparent from the description below.

BRIEF SUMMARY

According to a first aspect of the present invention, a forage harvester cracker unit comprises a base frame comprising left and right hand side elements, a first cracker roller being mounted on the base frame to be rotatable about a fixed central axis extending between the left and right hand side elements of the base frame and a secondary frame comprising left and right hand side elements, a second cracker roller being mounted on the secondary frame to be rotatable about a central axis extending between the left and right hand side elements of the secondary frame, wherein the forage harvester cracker unit further comprises a pivot axis extending through the base frame and the secondary frame, the secondary frame being adjustable about the pivot axis to enable variation of a separation of the first and second cracker rollers, a biasing element acting between the base frame and the secondary frame to urge the second cracker roller towards the first cracker roller and a drive element acting against the biasing element to hold the secondary frame in position against the biasing element to maintain a minimum separation of the first and second cracker rollers characterised in that characterised in that the drive arrangement comprises includes a drive shaft supported for rotation in bearings provided in the left and right hand side elements of the base frame, parallel levers eccentrically mounted on the left and right hand sides of the drive shaft, a distal end of each lever being retained within respective left and right hand side elements of the secondary frame so that rotation of the drive shaft about its axis results in movement of the secondary frame with respect to the base frame and the distance between the rolls to be varied.

Preferably, the biasing arrangement comprises parallel spring elements mounted on the base frame.

More preferably the spring elements act to pull the secondary frame towards the base frame. Even more preferably, the spring elements are mounted adjacent the first cracker roller.

Alternatively, the spring elements act to push the secondary frame towards the base frame. More preferably, the spring elements are mounted adjacent the second cracker roller.

Preferably, the drive arrangement further comprises an actuator to control rotation of the drive shaft.

Preferably, each of the left and right hand side elements of the secondary frame are provided with recessed portions to receive the distal end of each lever.

More preferably the distal end of each lever is provided with a pin to be received within the recessed portions of each of the left and right hand side elements of the secondary frame.

Within the scope of this application, it should be understood that the various aspects, embodiments, examples and alternatives set out herein, and individual features thereof may be taken independently or in any possible and compatible combination. Where features are described with reference to a single aspect or embodiment, it should be understood that such features are applicable to all aspects and embodiments unless otherwise stated or where such features are incompatible.

DETAILED DESCRIPTION

FIG.1shows a forage harvester provided with a front attachment2such as a header which contains cutting equipment for cutting and harvesting a crop. The cut crop is fed through a series of compression rolls3ain a compression roller housing3to a chopper drum4where the crop is chopped into smaller pieces. The chopped crop passes through a duct5and is optionally directed into a cracker unit6where the crop is further crushed and threshed. The harvested crop is then blown upwards along a duct5by an accelerator8and exits through a spout9.

FIGS.2and3show perspective views of a first embodiment of a cracker unit6for use in a forage harvester. A base frame10of the cracker unit6comprises first and second side panels12,14and connecting elements16extending between the first and second side panels12,14. Each side panel12,14is provided with a outwardly extending lower flange18,20and a post22,24secured to the side panel12,16and its lower flange18,20by any suitable means, for example by welding of the post22,24to the side panel12,14. The posts22,24are arranged parallel to one another and each post22,24conveniently extends at an angle to the adjacent lower flange18,20. In use the lower flanges are used to secure the cracker unit in position on a frame of the forage harvester2.

Corresponding first mounting blocks26,28are secured to a first side of each of the posts22,24. The first mounting blocks26,28each house a suitable bearing for supporting first and second ends of a first cracker roller30. In the illustrated embodiment, roller bearings are provided. The first mounting blocks26,28may be secured to the posts in any suitable manner, for example by bolts34(seeFIG.5).

On a second side of each of the posts22,24a secondary frame is provided. In the illustrated embodiment ofFIGS.2to7, the secondary frame comprises first and second end elements42,44each of generally triangular form. In use each of the first and second end elements42,44of the secondary frame is located adjacent to a respective side wall12,14and is located within a width defined by outer edges of the side flanges18,20.

Each of the first and second end elements42,44incorporate corresponding second mounting blocks46,48. The second mounting blocks46,48each house a suitable bearing for supporting first and second ends of a second cracker roller32. In the illustrated embodiment, roller bearings are provided.

The first and second end elements42,44of the secondary frame are also connected by an axle50extending through a lower end of each of the first and second end elements42,44. The axle50extends though suitable openings in the first and second side walls12,14of the base frame10. The axle50allows the secondary frame to pivot with respect to the base frame10about a central axis of the axle50.

An upper end of each first and second end element42,44adjacent a post22,24is provided with a mounting point. At each side of the cracker unit6a biasing arrangement58is secured to the mounting point. In the illustrated first embodiment ofFIGS.2to7, the biasing arrangement58comprises a central elongate shank member60provided at a first end with a threaded head and at a second end with an opening. The second end of the elongate shank member60is secured to the mounting point by a pivot pin62. A shank of the elongate member passes through an opening provided in the upper ends of each of the posts22,24. The threaded head is conveniently provided with by first and second nuts64,66. Before the first and second nuts64,66are secured in place a first washer68, a spring element72and a second washer70are located about the shank of the elongate shank member60. In use, each spring element72is under compression and so will seek to draw the respective first and second end elements42,44of the secondary frame towards the corresponding post22,24, that will (with reference toFIGS.2to6) cause the secondary frame to rotate clockwise about the axle50.

An upper end of each of the first and second end elements42,44of the secondary frame spaced from the posts22,24is provided with a recessed portion80.

The base frame10is provided at a second end with corresponding openings in the first and second side panels12,14. A drive shaft82extends through the openings. Ends of the drive shaft82serve as mountings for corresponding pivot levers84provided to each side of the cracker unit6. Lower ends of each pivot lever are mounted on an eccentric bearing.

The upper ends of each pivot lever84are provided with pins86adapted to be seated within the recessed portions80of the corresponding first and second end elements42,44. As may be seen fromFIG.5, the pins86are conveniently retained by threaded elements88secured within a threaded recess of a main part of each pivot lever84.

One end of the drive shaft82is connected to a drive90(seeFIG.7) such that longitudinal movement of a first shaft92causes the drive shaft82to be rotated. This in turn causes the pins86to pull down on the recessed portions80of the corresponding first and second end elements42,44of the secondary frame and so rotate the secondary frame about the axle50and away from the adjacent posts22,24. The drive90may be actuated in any convenient manner.

In this way separation of the first and second cracker rollers30,32can be controlled by operation of the drive90by an operator (for example by the operator entering a desired separation into a user interface located within a cab of the forage harvester2and an electronic control unit operating the drive to deliver the desired separation. The biasing element allows temporary widening of the gap between the first and second cracker rollers30,32to prevent overloading of the bearings in the event of an excessive flow of harvested crop or of the passage of a foreign object between the first and second cracker rollers30,32.

In a second embodiment, shown inFIG.8, the secondary frame again comprise first and second end elements142incorporating corresponding second mounting blocks146. Like reference numerals are used to refer to like parts. The first and second end elements of the secondary frame are again connected by an axle150extending through a lower end of each of the first and second end elements. The axle150extends though suitable openings in the first and second side walls of the base frame. The axle150allows the first and second end elements of the secondary frame to pivot with respect to the base frame110about a central axis of the axle150.

As in the first embodiment, an upper end of each of the first and second end elements of the secondary frame spaced from the posts is provided with a recessed portion180to be engaged by a suitable pin186on the associated pivot lever184. The pivot levers184to each side of the cracker unit are mounted on shaft182and are provided with a drive as in the first embodiment.

However, in the second embodiment, the secondary housing is not provided with a biasing element acting between the secondary frame elements and the adjacent posts. Instead, a biasing arrangement158is arranged to each side of the cracker unit extending between the lower flange118and the secondary frame elements142mounted above the lower flanges118.

Other elements of the cracker unit of the second embodiment correspond to those of the first embodiment.

As in the first embodiment, separation of the first and second cracker rollers30,32can be controlled by operation of the shaft182and the biasing arrangement158allows temporary widening of the gap between the first and second cracker rollers as required during operation of the cracker unit.

All references cited herein are incorporated herein in their entireties. If there is a conflict between definitions herein and in an incorporated reference, the definition herein shall control.