GB2126065A - Cutter bar - Google Patents

Abstract

A finger-bar cutter for harvesting machines with a cutting knife moving to and fro comprises knife blades 7 which are arranged on a knife bar and which interact as counter cutters with the cutting fingers, the cutting fingers consisting of a finger bottom part and a finger top part with a knife gap located between them, these being fastened to the finger bar at one of their ends and being connected firmly to one another in front of the knife- blade gap at their other end, and the knife blades being provided in their fastening part with recesses 15 for cleaning the knife-blade gap. The recesses may be open up to the blade base plate (24, 26, Figures 5 and 6); alternatively the recesses may be formed by fastening the blades on the knife bar at a certain distance from one another (Figure 7). The recesses may be provided with sloping flanks. <IMAGE>

Description

SPECIFICATION Cutter bar The invention relates to a finger-bar cutter for harvesting machines with a cutting knife moving to and fro and consisting of knife blades which are arranged on a knife bar and which interact as counter cutters with the cutting fingers.

In such known finger-bar cutters, the knife blades conventionally have a basic triangular shape. Two sides adjoining one another are ground and form the knife cutting edges, whilst the third side (the base side) serves for fastening and is conventionally located on the knife bar. To increase the stability, the individual blades are arranged on the knife bar so as to butt against one another, and the base side is usually extended somewhat and projects beyond the knife bar.

In this way, greater firmness is achieved on the knife bar as a result of a composite action between the individual blades.

The cutting fingers form the counter cutters for the knife blades located on the knife bar. Located above the actual counter cutters of these cutting fingers is the so-called finger lip which supports the material to be cut against the knife blade so that the stalks are not laid flat before they are cut off.

As a rule, the finger lips are fastened to the cutting-finger tip at one end only and consequentiy break off very easily when foreign bodies, such as, for example, stones, are pressed against the lips by the knife blade during the cutting operation.

To increase the stability of the finger lip, in various designs of the cutting fingers the finger lip has already been guided over the entire length of the blade and also screwed on by means of the cutting-finger fastening screw. Such a construction produces a very stable cutting finger, since not only is the finger lip stabilised in a lateral direction, but the entire cutting finger is also stabilised in a vertical direction, without a substantial increase in the weight of the finger being necessary.

However, inspite of the extremely high stability achieved, this cutting-finger design described above has not yet found general acceptance in practice, since it has a very serious disadvantage.

The material to be cut, which is drawn into the blade gap by the blades, cannot, as in conventional constructions, flow off to the rear because the finger lip is also screwed down at its end, and instead it accumulates in the blade gap, so that, depending on the type of crop which is being cut, complete bunches of stalks are gradually built up, and these not only prevent the cut material from flowing off to the rear, but after a certain time jam the cutting knife entirely.

In practice, therefore, the cutting finger conventional hitherto, with a finger lip open to the rear, continues to be used as before.

In conjunction with this cutting finger, in order to clean the cutter bar, to reduce the mass of the cutting knife moving to and fro and achieve higher elasticity of the knife blades, it has already been proposed to provide the latter with recesses.

Blades of this type are described, for example, in Swiss Patent Specification 174,923, the two German Utility Models 1,715,760 and 1,765,200 and German Offenlegungsschrift 2,451,106.

However, even these blades provided with recesses have not been successful in the past because conventional cutting fingers with finger lips open to the rear necessitate special knife pressure plates which are attached to the cutter bar at certain intervals and which press the blades against the counter cutters of the bottom parts of the cutting fingers.

When the individual blades are provided with recesses, these recesses in the very hard blades act on the knife pressure plates like sharp scrapers and wear away the knife pressure plates completely within a short time.

The knife-blade recesses mentioned in the above specifications have therefore failed to achieve any kind of importance in practice.

In connection with comprehensive tests which the Applicant has carried out on the cutting fingers mentioned in the introduction, with a top part guided to the rear and screwed to the knife bar, it was discovered that surprisingly the difficulties described above can be overcome in this type of cutting finger and that a finger-bar cutter for harvesting machines which has extremely high stability can be provided if: a) the cutting fingers consist of a finger bottom part and a finger top part with a knife gap located between them, these being fastened to the finger bar at one of their ends and being connected firmly to one another in front of the knife-blade gap at their other end and, b) the knife blades are provided with recesses in their fastening part.

In finger-bar cutters designed in this way, the top part of the finger performs the function of guiding the knife blades. The finger pressure plates conventional hitherto, which are also known as "thumbs" in the specialised language, are no longer necessary. Consequently, in the cutting fingers used according to the invention, the above-mentioned difficulties with the recesses in the knife blades also do not arise.

On the contrary, in the combination according to the invention, these recesses in the knife blades ensure that all the material to be cut, which is drawn into the blade gap, is transported out of the blade gap again as a result of the to-and-fro movement of the cutting knife.

It has not been possible to detect any adverse influence on the guidance of the cutting knife, which is performed by the top part of the finger, because in the embodiment according to the invention the cutting knife, guided by the finger top part of each cutting finger, has a substantially smoother movement than when the few finger pressure plates distributed over the cutter are used.

In the cutting-finger design used according to the invention, both the finger bottom part and the finger top part can serve as a counter cutter for the knife blade. It is also already known, in such cutting-finger constructions, to arrange the knife blades on the knife bar in an alternating sequence with regard to the ground surfaces of their cutting edges.

However, it was shown, surprisingly, that this feature, together with the combination of features according to the invention, produces an especially advantageous effect in that the finger-bar cutter according to the invention, designed in this way, has an extremely smooth movement and extremely low wear, especially as regards the knife guide.

Alternating cutting, first in conjunction with the counter cutter of the top part, then at the next blad in conjunction with the counter cutter of the bottom part, and so on, results in a completely uniform knife movement in which the individual knives themselves compensate the forces arising during cutting and directed transversely to the direction of movement, so that the knife floats practically freely in the knife gap.

The recesses provided according to the invention in the knife blades reliably remove all the stalk materials introduced into the knife gap, so that the difficulties which have arisen hitherto are safely avoided.

At the same time, it has proved especially advantageous to provide the recesses in the knife blades with sloping flanks by means of which the recesses are widened downwards.

As a result of such a design of the recesses, the stalk parts entering the recess can fall out freely downwards due to gravity.

According to the present invention, the recesses formed in the knife blades can be designed as punched holes of any shape. They can be, for example, round, triangular, polygonal or oval recesses or recesses of another shape, the triangular or polygonal embodiments appropriately being provided with rounded corners.

According to another advantageous embodiment of the present invention, it has proved appropriate to design the recesses as reces3es which are open towards the blade base edge. This additionally enables stalk parts also to enter this recess from the side and thus to be transported out of the blade gap.

According to another advantageous embodiment of the present invention, the recesses are formed between adjacent knife blades because these are arranged at a distance from one another.

According to another advantageous embodiment, the recesses are formed by chamfers extending from the blade base edge between two adjacent blades, and consequently have a triangular shape.

In a finger-bar cutter according to the invention, the knife blades can be used with recesses which are the same as or of different design from those described in detail above.

Of the embodiments, described in detail above, of the recesses in the blades or between the blades, the recesses closed on the base side have proved the most favourable embodiment because in these the base side of the blade is not interrupted. This results, on the one hand, in higher stability of the blade despite a larger recess and, on the other hand, because there is no interruption in the base side, in a larger bearing surface on the knife guide plate and therefore less wear.

Instead of the recesses in the blades, it is also possible for the shoulders of the blades butting closely against one another to be bevelled. This again results in recesses which have an approximately triangular base shape.

In so-called double-knife cutters, that is to say, cutters without cutting fingers, in which two cutting knives are moved to and fro in opposite directions to one another, thus resulting in a shearing cut, there are known to be cutting knives, the individual blades of which do not butt against one another, as is conventional in finger-type cutters, but are fastened to the knife bar at a greater or lesser distance from one another. This results in interspaces which are likewise suitable as cleaning recesses.

The invention is explained in more detail below with reference to the exemplary embodiments illustrated in the drawings, in which: Figure 1 shows a side-view of a cutting finger of conventional design; Figure 2 shows a cutting finger, the top part of which is guided up to the finger bar and is screwed on there; Figure 3 shows an embodiment according to the invention of the cutting knife in the cutter bar, seen from above; Figure 4 shows a preferred embodiment of the invention; Figure 5 shows various embodiments of the recesses in the knife blade; Figure 6 shows two blades with chamfered shoulders; Figure 7 shows the spaced-out arrangement of the blades on the knife bar; Figure 8 shows the design of the recesses of the knife blade with sloping flanks in the form of a section along the line A-B in Figure 4.

In the conventional design illustrated in Figure 1, the cutting finger 1 is screwed to the finger bar 3 by means of the cutting-finger fastening screw 2. The knife gap 6 is located between the finger bottom part 4 and the finger lip 5. The flanks of the cutting finger 1 serve as counter cutters for the cutting-knife blades 7. Consequently, material to be cut, which is drawn into the knife gap 6, passes out again at 8, i.e. the rear end of the finger lip 5, and slides off to the rear.

A disadvantage of this known embodiment is that the finger lip 5 is connected only to the finger tip 9. When the cutting fingers are very slender, this connection is very weak. The finger lip 5 is therefore very frequently torn off by foreign bodies.

The bow-shaped knife pressure plate 10 (also known as a knife thumb) presses on the knife blade 7 and retains the cutting knife 11 in its guide. This is formed, on the one hand, by the bottom part of the cutting finger and, behind the knife bar, by the knife guide plate, also called a friction plate. Blades with recesses cannot be used in this embodiment, because these recesses wear the knife thumb away very quickly with their sharp edges. The blade then lifts off from the counter cutter of the cutting finger and merely squeezes the material to be cut, instead of cutting it off.

In the cutting finger illustrated in Figure 2, the finger lip is extended to the rear and forms the finger top part 13. This is connected at its front end to the finger tip and at its rear end is screwed to the finger bar 3 by means of the finger fastening screw 2, As a result, the cutting finger acquires very high vertical stability, even when it is very slender.

However, in this embodiment, stalks which are drawn into the knife gap 6 can no longer slide out to the rear. They loop round the finger top part 13, build up against the curve 14 of the rivet hole for the cutting knife or against the connecting web 1 6 (see Figure 3) and form bunches which interfere with the cut material when it slides off to the rear.

Depending on the type of material to be cut, the bunches can become so thick that the cutting blade is jammed and can move to and fro only with great difficulty.

The recesses 1 5 in the knife blades 7 ensure that even individual stalks can immediately be drawn forward again out of the finger top part 13 as soon as the recess 1 5 in the blade 7 leaves the finger in the opposite direction. There is therefore no risk of bunching at all.

The stability of the knife blades 7 is scarcely impaired by the recess, since, because of the basic triangular shape of the knife blades 7, the load in the region of the recess is, in any case, approximately zero. On the other hand, there is the further additional advantage that the masses moving to and fro are less, and this has a very advantageous effect on the load on the drive elements.

Figure 3 shows an especially advantageous combination of cutting fingers with top parts screwed down at 1 7. In this case, two particular cutting fingers 1 8 and 1 9 are connected together by means of the web 16 to form a so-called double finger. Stalks which are drawn into the blade gap are prevented at 20 by the web 1 6 from travelling further to the rear. They then force their way into the recesses 1 5 in the knife blades 7 and are drawn out of the blade gap in the way described above.

In this preferred exemplary embodiment, the recess 1 5 is designed as a perforation or punched hole in the knife blade. The base edge 21 of the blade is not interrupted. This results in an uninterrupted bearing surface 22 on the knife guide plate 12, and this proves to be subjected to substantially less wear than embodiments in which the recess is open up to the blade base edge.

However, it is also possible and, under some circumstances, even necessary to use blades with recesses which are open up to the blade base edge, for example those of the type illustrated in Figures 5 and 6. If, for example, cutting fingers not connected together by means of a web 1 6 to form a double finger are used, the stalks drawn in can slide further to the rear, so that they are no longer grasped by the recess 1 5 according to Figure 4. In this case, the recesses according to Figures 5 and 6 prove especially advantageous because they push the drawn-in material to be cut out again by means of their edges 23.

In the exemplary embodiment illustrated in Figure 3, it has proved very advantageous to fasten on the knife blade 11 one blade with the ground surface at the top and the adjacent blade with the ground surface at the bottom. The blade 7 is fastened in a conventional way with the ground surface at the top, that is to say it cuts on the lower finger, and the blade 7a is fastened with the ground surface at the bottom, that is to say it cuts on the upper finger.

Such a blade arrangement ensures that the cutting forces which endeavour to lift the blades away from the counter cutters are compensated.

The entire knife therefore "floats" in the blade gap formed by the cutting fingers and is held completely in suspension. It is clear, and therefore requires no further explanation, that an arrangement of this type reduces the wear very substantially.

Of course, the embodiment illustrated is not restricted to operation with the knife blades according to the Figures 5 and 6, but also affords considerable advantages when the blades used are perforated according to Figure 4.

The shape of the recesss in the blades can differ according to the intended use. Because there are various types of material to be cut, different shapes and also different sizes of these recesses may be necessary. All shapes are possible, ranging from circular through to trapezoidal, triangular or polygonal. The recesses according to Figures 5 and 6 are also only exemplary embodiments, the shape and size of which can be varied in a multiplicity of modifications.

In Figure 7, the recesses required according to the invention are formed by fastening the blades 27 on the knife bar 11 at a certain distance from one another. This produces the interspaces 28 which have the same effect as the recesses made directly in the blades.

Figure 8 illustrates a special embodiment of the present invention in which the recess in the knife blade is provided with sloping flanks by means of which the recesses are widened downwards, that is to say, towards the ground.

Claims (9)

1. Finger-bar cutter for harvesting machines with a cutting knife moving to and fro and consisting of knife blades (7) which are arranged on a knife bar (11) and which interact as counter cutters with the cutting fingers (1), characterised in that a) the cutting fingers (1) consist of a finger bottom part and a finger top part (13) with a knife gap located between them, these being fastened to the finger bar (3) at one of their ends and being connected firmly to one another in front of the knife-blade gap at their other end, and b) the knife blades (7) are provided with recesses (15,24,26, 28) in their fastening part.

2. Finger-bar cutter according to Claim 1, characterised in that the knife blades (7) are arranged on the knife bar (11) in an alternating sequence as regards the ground surfaces of their cutting edges.

3. Finger-bar cutter according to Claim 1 or Claim 2, characterised in that the recesses (15, 24, 25, 26, 28) in the knife blades are provided with sloping flanks by means of which the recesses are widened downwards.

4. Finger-bar cutter according to one or more of Claims 1 to 3, characterised in that the recesses are designed as punched holes (15) of any shape in the knife blade (7).

5. Finger-bar cutter according to one or more of Claims 1 to 3, characterised in that the recesses are designed as recesses (24, 25) open towards the blade base edge.

6. Finger-bar cutter according to Claim 5, characterised in that the recesses (28) are formed between adjacent knife blades because these are arranged at a distance from one another on the knife bar (11).

7. Finger-bar cutter according to Claim 5, characterised in that the recesses are formed by chamfers (26) extending from the blade base edge between two adjacent blades.

8. Finger-bar cutter according to one or more of Claims 1 to 7, characterised in that the knife blades (7) are provided with recesses (15,24,25, 26, 28) or different designs.

9. Finger-bar cutter substantially as described with reference to and as illustrated in any one or more of the figures of the accompanying drawings.