GB1559322A - Forage harvesters - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO FORAGE HARVESTERS (71) We, WESTERN MACHINERY & EQUIPMENT COMPANY LIMITED, a British Company of Redlake Trading Estate, Ivybridge, Devon, PL21 OE2, do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention concerns improvements in or relating to forage harvesters and more particularly to apparatus of the kind known as precision chop or metered feed forage harvesters, and which chop forage or other agricultural crop or the like raised from the ground into short lengths by a rotating set of knives generally in the form of a cylinder with the knives projecting from the circumference, or a wheel with the knives mounted radially which cut the forage against a counter knife, provision being made either to cut the forage from the ground over a desired width in front of the machine, or to provide a pick-up unit of desired width to raise pre-cut material from the ground or to provide a maize harvesting attachment for one or more rows. The raised material may be fed to a screw conveyor designed to reduce the width of the material fed from either the cutter bar or pick-up unit to a width suitable for the feed rollers which feed the chopping cylinder. The chopped forage is then either thrown up a delivery chute by the chopping cylinder to a suitable collecting vehicle, or transferred by screw conveyor or direct to a fan of special type which throws the material through the delivery chute into the collecting vehicle.

The apparatus of the above kind is normally built on a wheeled chassis, for towing over the ground by an agricultural tractor which also drives it, but it can also be tractor mounted, self propelled or tractor towed with engine drive.

A serious drawback experienced with forage harvesters of the kind referred to is that serious and extensive damage can result to the machine in the event of a foreign body, e.g. a stone, or a loose piece of metal, passing into the cutting cylinder and which would prove to be exceedingly costly to repair.

The primary object of the present invention is to provide a cutting and chopping cylinder that is so constructed that comparatively little damage is caused should a stone enter the cylinder and which in any case can be remedied reasonably quickly and inexpensively.

According to the present invention, there is provided a cutting or chopping cylinder for a forage harvester having mounted thereon a plurality of knives having cutting edges that co-act with a counter knife, characterised in that each knife is weakened adjacent to a position at which it is mounted on the cylinder so that it is capable of yielding and deforming, and further that it is so mounted so as to be caused, when deformed, to bend and retract from its full operating radius into the working diameter of the cylinder.

The invention also includes the provision of a forage harvester of the kind referred to fitted with an improved cutting or chopping cylinder fitted with knives constructed as set forth in the preceding paragraph.

To enable the invention to be clearly understood and readily carried into effect a preferred embodiment thereof will now be described by way of example with reference to the accompanying drawings, wherein: Figure 1 is perspective view of one form of chopping cylinder provided with cutting knives constructed according to this invention.

Figure 2 is a plan view of a knife.

Figure 3 is a side elevation of Figure 2 and Figure 5.

Figure 4 is a purely diagrammatic view illustrating normal and deformed conditions of a knife.

Figure 5 is a plan view of a second form of chopping cylinder knife to which the invention can be applied wherein individual knives extend completely across the cylinder.

Figure 6 is a purely diagrammatic view illustrating a chopping cylinder with its housing, counter knife and part of a discharge chute.

Figure 7 is a view of an apparatus to which a chopping cylinder constructed according to this invention maybe fitted looking from the front, and adapted to be towed and driven by an agricultural tractor, and Figure 8 is a view of Figure 7 looking from the right hand end.

Referring to said drawings, the chopping or cutting cylinder is indicated generally at 1 and the knives 2 are mounted approximately radially on the circumference, but in such a way that the angle of the mounting plate compensates for the cutting angle of the knife, to place the knife tip 2a approximately on or trailing the maximum radius of the said knife when mounted on the chopping cylinder. Each knife 2 is so shaped that it is weaker in the area 3 having cut-away side portions 3a immediately adjoining the securing bolts, and is made of suitable steel and heat treated to make it malleable or pliable at the area 3 so that when foreign bodies enter the machine the said knife yields and bends backwards as indicated at positions "X" and "Y" in Figure 4 causing the tip 2a to retract within the working diameter of the cylinder and its casing 4, Figure 4. The knives are heat treated in such a way that their cutting edges are left sufficiently hard.

The knives 2 can be made the full width of the cylinder as illustrated by Figure 5 but with areas 6 of the knife cutaway adjacent to the securing bolts. However, tests have shown that it is advantageous to produce the knives in segments, i.e. to fit thirty-six segments for a twelve knife cylinder as illustrated in Figure 1. However any reasonable number of segments may be used.

From the foregoing it will be appreciated that in the event of a foreign body, e.g. a stone or a loose piece of metal entering the cutting cylinder and becoming caught or wedged between one or more of the knives 2 and its counter knife 5 or the casing 4, the or each affected knife will yield and bend backwards and so absorb shock loading and thereby protect the chopping cylinder.

Figure 4 illustrates three conditions of a knife, viz. the normal undeformed condition shown at position "Z" and the position "X" and "Y" already referred to, the position "X" illustrating bending and distortion of the knife due to a light impact and strain and the position "Y" illustrating bending and distortion of a knife subjected to a severe impact and strain. Distortion of a knife prevents any extensive damage to the chopping cylinder and only necessitates replacement of a damaged knife.

It is a further feature of this invention that in the event of the knives 2 yielding and bending backwards they will retract within the full working diameter of the chopping cylinder and its housing, and that damage to the counter knives, cylinder housing, discharge chute and the machine in general will be eliminated or greatly lessened. Additionally, safety of the operator will be increased because the damaged knives will remain on the chopper cylinder and because the reduced likely damage to the machine casing greatly reduces the possibility of foreign bodies and parts of the machine being discharged violently.

The chopping cylinder described above can be used with all cylinder crop forage harvesters, either tractor towed and driven, tractor mounted, tractor towed with engine drive or self propelled.

WHAT WE CLAIM IS: 1. A rotary cutting or chopping cylinder for a forage harvester having mounted thereon a plurality of knives having cutting edges that co-act with a counter knife, characterised in that each knife is weakened adjacent to a position at which it is mounted on the cylinder so that it is capable of yielding and deforming, and further that it is so mounted so as to be caused, when deformed, to bend and retract from its full operating radius into the working diameter of the cylinder.

2. A cutting cylinder as claimed in Claim 1, wherein the weakening of each knife is achieved by suitably controlling heat treatment thereof to render it malleable or pliable at an area where it is mounted on the cylinder.

3. A cutting cylinder as claimed in Claim 1 or 2, wherein each knife comprises a plurality of segments extending across the full width of the cylinder.

4. A cutting cylinder as claimed in Claim 1 or 2, wherein each knife is a one-piece knife extending across the full width of the machine.

5. A cutting cylinder as claimed in any of the preceding claims wherein mounting plates for the knives are each positioned to compensate for the cutting angle of a knife and position the cutting tip of the knife on or trailing its position of maximum radius when in the normal undamaged working position, the plates being adapted either to carry full width knives or knives composed of segments.

6. A cutting or chopping cylinder for a forage harvester, constructed substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

7. A forage harvester of the type referred to fitted with a cutting cylinder as claimed

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. Figure 5 is a plan view of a second form of chopping cylinder knife to which the invention can be applied wherein individual knives extend completely across the cylinder. Figure 6 is a purely diagrammatic view illustrating a chopping cylinder with its housing, counter knife and part of a discharge chute. Figure 7 is a view of an apparatus to which a chopping cylinder constructed according to this invention maybe fitted looking from the front, and adapted to be towed and driven by an agricultural tractor, and Figure 8 is a view of Figure 7 looking from the right hand end. Referring to said drawings, the chopping or cutting cylinder is indicated generally at 1 and the knives 2 are mounted approximately radially on the circumference, but in such a way that the angle of the mounting plate compensates for the cutting angle of the knife, to place the knife tip 2a approximately on or trailing the maximum radius of the said knife when mounted on the chopping cylinder. Each knife 2 is so shaped that it is weaker in the area 3 having cut-away side portions 3a immediately adjoining the securing bolts, and is made of suitable steel and heat treated to make it malleable or pliable at the area 3 so that when foreign bodies enter the machine the said knife yields and bends backwards as indicated at positions "X" and "Y" in Figure 4 causing the tip 2a to retract within the working diameter of the cylinder and its casing 4, Figure 4. The knives are heat treated in such a way that their cutting edges are left sufficiently hard. The knives 2 can be made the full width of the cylinder as illustrated by Figure 5 but with areas 6 of the knife cutaway adjacent to the securing bolts. However, tests have shown that it is advantageous to produce the knives in segments, i.e. to fit thirty-six segments for a twelve knife cylinder as illustrated in Figure 1. However any reasonable number of segments may be used. From the foregoing it will be appreciated that in the event of a foreign body, e.g. a stone or a loose piece of metal entering the cutting cylinder and becoming caught or wedged between one or more of the knives 2 and its counter knife 5 or the casing 4, the or each affected knife will yield and bend backwards and so absorb shock loading and thereby protect the chopping cylinder. Figure 4 illustrates three conditions of a knife, viz. the normal undeformed condition shown at position "Z" and the position "X" and "Y" already referred to, the position "X" illustrating bending and distortion of the knife due to a light impact and strain and the position "Y" illustrating bending and distortion of a knife subjected to a severe impact and strain. Distortion of a knife prevents any extensive damage to the chopping cylinder and only necessitates replacement of a damaged knife. It is a further feature of this invention that in the event of the knives 2 yielding and bending backwards they will retract within the full working diameter of the chopping cylinder and its housing, and that damage to the counter knives, cylinder housing, discharge chute and the machine in general will be eliminated or greatly lessened. Additionally, safety of the operator will be increased because the damaged knives will remain on the chopper cylinder and because the reduced likely damage to the machine casing greatly reduces the possibility of foreign bodies and parts of the machine being discharged violently. The chopping cylinder described above can be used with all cylinder crop forage harvesters, either tractor towed and driven, tractor mounted, tractor towed with engine drive or self propelled. WHAT WE CLAIM IS:

1. A rotary cutting or chopping cylinder for a forage harvester having mounted thereon a plurality of knives having cutting edges that co-act with a counter knife, characterised in that each knife is weakened adjacent to a position at which it is mounted on the cylinder so that it is capable of yielding and deforming, and further that it is so mounted so as to be caused, when deformed, to bend and retract from its full operating radius into the working diameter of the cylinder.

2. A cutting cylinder as claimed in Claim 1, wherein the weakening of each knife is achieved by suitably controlling heat treatment thereof to render it malleable or pliable at an area where it is mounted on the cylinder.

3. A cutting cylinder as claimed in Claim 1 or 2, wherein each knife comprises a plurality of segments extending across the full width of the cylinder.

4. A cutting cylinder as claimed in Claim 1 or 2, wherein each knife is a one-piece knife extending across the full width of the machine.

5. A cutting cylinder as claimed in any of the preceding claims wherein mounting plates for the knives are each positioned to compensate for the cutting angle of a knife and position the cutting tip of the knife on or trailing its position of maximum radius when in the normal undamaged working position, the plates being adapted either to carry full width knives or knives composed of segments.

6. A cutting or chopping cylinder for a forage harvester, constructed substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

7. A forage harvester of the type referred to fitted with a cutting cylinder as claimed

in any of the preceding claims.

8. A forage harvester fitted with a maize harvesting unit for one or more rows fitted with a cutting cylinder as claimed in any of Claims 1 to 6.