Cutting blade overlaod protection

Abstract

A cutting blade overload protection device for a cutting mechanism of a harvester for leaf and stalk material, having a cutting blade pivotable about a cutting blade rotational axis and which is connected to a toggle lever mechanism. The toggle lever mechanism includes two coupled toggle levers pivotable about a toggle lever rotational axis and which move the cutting blade from an operating position to a resting position when a predefined force is exceeded. To protect the cutting blade better when contacting foreign objects, the device has a toggle lever mechanism which comprises a stop limit and a spring element, with the spring element and limit stop interacting such that when a predefined force is exceeded, the toggle lever rotational axis is moved past a dead center point, with the position of the toggle levers shifting from a first buckling position through a straight position into a second buckling position.

Claims

1. A toggle lever mechanism (14) comprising: two toggle levers (16, 17) that are coupled to one another and pivotable about a toggle lever rotational axis (15) and which are movable from an operating position (P1) to a resting position (P2) when a predefined force (F1) acting on the toggle lever mechanism (14) has been exceeded; a limit stop (24); and a spring element (19), wherein the limit stop (24) forms a guide element (18) which is in contact with a toggle lever (16, 17) and the toggle lever (16, 17) contacting the limit stop (24) includes a guide track in the form of an inclined plane (28) along which the limit stop (24) can slide or roll, with the spring element (19) and the limit stop (24) interacting such that when the predefined force (F1) is exceeded, the toggle lever rotational axis (15) is moved past a dead center point (20) and the position of the toggle lever (16, 17) shifts from a first buckling position (21) to a second buckling position (23).

2. A cutting blade overload protection device (10) for a cutting mechanism (11) of a harvester (100) for leaf and stalk material, comprising: at least one cutting blade (13) that is pivotable about a cutting blade rotational axis (12); and a toggle lever mechanism (14) as claimed in claim 1 with which the cutting blade (13) is movable from an operating position (P1) to a resting position (P2) when a predefined force (F1) has been exceeded.

3. The cutting blade overload protection device (10) as claimed in claim 2, wherein a force (FR) acting on the toggle lever mechanism comprises a buckle force component (FN) and a compression force component (FK) and: when the cutting blade (13) is in operating position (P1), the buckle force component (FN) presses the toggle lever mechanism (14) against the limit stop (24) in direction (R3); as force (FR) increases, the buckle force component (FN) oriented in direction (R3) is reduced; upon attaining the predefined value (F1), force (FR) moves the toggle lever mechanism into the dead center position (20) in which a force (FDY) or (FN) acting in toggle lever swivel joint (49) measures zero Newtons; and when force (FR) exceeds the predefined value (F1), said force (FR) moves the toggle lever swivel joint (49) away from the limit stop in direction (R2), with the result that the dead center position (20) is passed and the cutting blade overload protection device (10) triggered by the passing of the dead center position (20) moves the cutting blade (13) into resting position (P2).

4. The cutting blade overload protection device (10) as claimed in claim 2, wherein when changing from the operating position (P1) into the resting position (P2), the toggle lever mechanism (14) passes out of the first buckling position (21) through a straight position (22) and into the second buckling position (23).

5. The cutting blade overload protection device (10) as claimed in claim 2, wherein the position of the limit stop (24) is adjustable with respect to the toggle lever (16).

6. The cutting blade overload protection device (10) as claimed in claim 2, wherein the toggle lever (16) includes a contact area (27) that is configured as an inclined plane (28).

7. The cutting blade overload protection device (10) as claimed in claim 2, wherein the toggle lever (16, 17) comprises individual components (29, 30) which are coupled to one another by means of the spring element (19) such that the length (L1; L2) of the toggle lever (17) is dependent on the magnitude of force (FR) and thus on the magnitude of the force (FK) acting on the spring element (19).

8. The cutting blade overload protection device (10) as claimed in claim 2, wherein the spring element (19) is arranged between the cutting blade (13) and the toggle lever (16) or between a supporting frame (31) connected to the toggle lever (17) and the toggle lever (17).

9. The cutting blade overload protection device (10) as claimed in claim 2, wherein: a first of the two toggle levers (16) comprises at an end opposite the toggle lever rotational axis (15) a first swivel joint (57) with a first pivot axis (157); and a second of the two toggle levers (17) comprises at an end opposite the toggle lever rotational axis (15) a second swivel joint (58) with a second pivot axis (158); the two toggle levers (16, 17) include a common swivel joint (49) with the toggle lever rotational axis (15); and at least one of the swivel joints (49, 57, 58) includes the spring element (19), which is elastically deformed when a force (FR) acts on the toggle lever mechanism (14).

10. The cutting blade overload protection device (10) as claimed in claim 2, wherein an elastic plastic block (32) is provided as the spring element (19).

11. The cutting blade overload protection device (10) as claimed in claim 2, wherein the spring element (19) includes at least two individual springs (33, 34).

12. The cutting blade overload protection device (10) as claimed in claim 2, further comprising a tensioning device (35) for preloading the spring element (19).

13. The cutting blade overload protection device (10) as claimed in claim 2, wherein the spring element (19) is coupled to a guide means (36) in order to prevent the spring element (19) from breaking out laterally when subjected to a load.

14. The cutting blade overload protection device (10) as claimed in claim 2, further comprising a restoring means (37) for moving the cutting blade from the resting position (P2) into the operating position (P1).

15. A harvester (100) for leaf and stalk material, comprising at least one of: at least one cutting blade overload protection device (10) as claimed in 2; and a toggle lever mechanism as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described in more detail in an exemplary embodiment and accompanying figures, where:

(2) FIG. 1 shows a side view of the front section of a harvester;

(3) FIG. 2 shows part of the front section of FIG. 1 with a cutting blade in its operating position and the toggle lever mechanism in a first buckling position;

(4) FIG. 3 shows the toggle lever mechanism of FIG. 2, first buckling position;

(5) FIG. 4 shows a section of the front part of FIG. 1 when the cutting blade is moved out of its operating position, toggle lever mechanism at dead center position;

(6) FIG. 5 shows the toggle lever mechanism of FIG. 4, dead center position;

(7) FIG. 6 shows a section of the front part of FIG. 1 with the cutting blade moved out into its resting position, toggle lever mechanism in a second buckling position;

(8) FIG. 7 shows the toggle lever mechanism of FIG. 6, second buckling position;

(9) FIG. 8 shows an exploded view of the toggle lever components;

(10) FIG. 9 shows the toggle lever mechanism in an assembled view;

(11) FIG. 10 shows a further example of a blade protection system with a toggle lever mechanism pressed against the limit stop, cutting blade in its operating position (first state);

(12) FIG. 11 shows the blade protection system of FIG. 10, with the toggle lever mechanism at the dead center position (second state);

(13) FIG. 12 shows the blade protection system of FIGS. 10 and 11, toggle lever mechanism immediately after passing the dead center position (third state); and

(14) FIG. 13 shows the blade protection system of FIGS. 10 to 12, toggle lever mechanism completely moved out, cutting blade in its resting position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(15) Identical or similar elements in the following figures can be provided with identical or similar reference numbers. Furthermore, the figures of the drawing, its description as well as the claims contain numerous features in combination. Here it is clear to the person skilled in the art that these features can also be regarded individually, or they can be brought together in further combinations.

(16) FIG. 1 shows a side view of the front part of a partially represented harvester 100 in the manner of a schematic cross-sectional diagram. The harvester 100 is an exemplary loader wagon, but the cutting blade overload protection device 10 can also be employed in other harvesters for leaf and stalk material, in particular in balers.

(17) The harvester 100 has a reel 51 for picking up harvested material, for example grass. The harvested material (not shown) is fed by the reel 51 to a feed rotor 40 which comprises a supporting tube 41 and feed tines 42 attached thereto. In the shown exemplary embodiment, eight feed tines 42 form a feed tine star. The feed rotor 40 includes a plurality of such feed tine stars arranged next to each other axially to the rotational axis of the feed rotor 40. The feed tines 42, or feed tine stars, do not abut each other in the axial direction but instead are spaced apart, thus forming gaps though which the cutting blade 13 is guided during operation.

(18) The feed tines 42 have tine tips 52 which define an external cylinder 43 of the feed rotor 40. A conveyor trough 44 extends around one part of the external cylinder 43. A conveyor channel 45 is thus formed between the supporting tube 41 of the feed rotor 40 and the conveyor trough 44. The harvested material fed during operations by the rotating reel 51 to the likewise rotating feed rotor 40 is fed by the feed tines 42 through the conveyor channel 45 to a loading space 53 of the harvester 100 following the conveyor channel 45.

(19) The conveyor trough 44 has slit-like openings (not shown) arranged adjacent to one another and through which the cutting blades 13 extend into the conveyor channel 45 and project there into the gaps located between the feed tines. When the feed rotor 40 rotates, the feed tines 42 are thus guided along the cutting blades 13, with the feed tines 42 functioning as shear blades for the fixed cutting blades 13. The harvested material passing through the conveyor channel 45 is cut by the cutting blades 13, with the cutting length of the harvested material being defined by the spacing distance of the cutting blades 13.

(20) The cutting blades 13 are coupled via blade holders 54 to a supporting structure 55 or support frame 31 and together form a cutting mechanism 11 that is pivotable about a rotational axis 56. When the cutting mechanism 11 is swung out, all cutting blades 13 are located outside of the conveyor channel 45.

(21) The cutting blades 13 can not only be swung in and out of the conveyor channel 45 together by means of the cutting mechanism 11, but can also be swung in and out of the conveyor channel 45 individually about a cutting blade rotational axis 12. The swing-out motion is made in the direction R2 as shown in FIG. 2, the swing-in motion in the opposite direction. The position of a cutting blade 13 swung into the conveyor channel 45 is designated as the operating position P1, the position when swung out of the conveyor channel 45 is designated as the resting position P2.

(22) The swinging-out movement of a cutting blade 13 about the cutting blade rotational axis 12 is controlled by a toggle lever mechanism 14. This toggle lever mechanism 14 comprises the cutting blade overload protection device 10 according to the invention. The operating modes of the overload protection device 10 are illustrated in three “snapshots” of a first exemplary embodiment as shown in FIGS. 2 to 7.

(23) FIG. 2 shows part of the harvester's front section with a cutting blade 13 completely immerged in the conveyor channel 45. The cutting blade 13—as well as the entire cutting mechanism 11—is thus situated in operating position P1. A foreign object 50, for example a stone, is located in the harvested material (not shown) in the conveyor channel 45. FIG. 2 shows the moment at which the foreign object 50 is located directly between a feed tine 42 and the cutting blade 13.

(24) In FIG. 3, the toggle lever mechanism 14 from FIG. 2 is shown in a detached view for better visualization. The two toggle levers 16 and 17 have a common toggle lever swivel joint 49 with a toggle lever rotational axis 15. At its second end the toggle lever 16 is coupled to the cutting blade 13 by means of a swivel joint 57. Toggle lever 17 is coupled at its second end by a swivel joint 58 to the supporting structure 55 and has a length L1 between the swivel joints 49 and 58.

(25) Toggle lever 16 rests against a limit stop 24 situated on the supporting structure 55. The limit stop 24 has a rounded contour 25 and forms a guide element 18 for the movement of the toggle lever 16. The two toggle levers 16 and 17 form an angle β1, which in the first exemplary embodiment shown in FIGS. 2 to 7 is greater than 180°. In the following, this position of the toggle lever mechanism will be designated as the first buckling position 21.

(26) At the moment of contact between the foreign object 50 and the cutting blade 13, a torque M arises about the rotational axis 12 of the cutting blade 13 due to the rotation of the feed rotor 40. The force exerted on the blade is transferred to the components of the toggle lever mechanism. Torque M thus transfers the force acting on the cutting blade 13 to a contact point P01 of the cutting blade and toggle lever 16 or the toggle lever mechanism 14. The cutting blade rotational axis 12 is fixed in a permanent position, the contact point P01 represents a kind of satellite with respect to the stationary rotational axis 12. When force is transferred to point P01, any existing play between the components, particularly in the region of the joints, is overcome and the components are pressed against one another at their respective contact points. Resulting from the torque about the rotational axis 12 is thus a force vector FR, which is transferred via the swivel joint 57 to the toggle lever mechanism 14.

(27) Since the toggle lever swivel joint 49 in the exemplary embodiment shown in FIG. 3 to FIG. 7 lies in front of the connection line of the swivel joints 57 and 58 as seen in the deflection buckling direction R2, the angle β1 is greater than 180°. The toggle lever mechanism 14 cannot buckle in the deflection buckling direction R2. The torque M applied about the rotational axis 12 is transferred as a resultant force FR to the contact point P01 located in region of the swivel joint 57 between cutting blade 13 and swivel joint 57. The force vector applied to the contact point P03 can also be designated as force vector FR″. In an analogous manner, a force vector FR transferred to the contact point P02 of limit stop 24 and toggle lever 16 is designated as FR′. The force FR, as well as FR′ and FR″, can be broken down into a component force FN, which is transferred to the limit stop 24, and a component force FK, which is transferred through the toggle lever swivel joint 49 to the toggle lever 17 (see FIG. 10). The force FN can also be designated as a buckling force, since this force acts in the deflection buckling direction (direction R2) or in the pressure buckling direction (direction R3).

(28) A spiral spring 38, which may be provided for retrieving the cutting blade from its resting position P2 to its operating position P1, has no load effect here. The blade protection device also functions without this spiral spring 38. Although the spiral spring 38 is preloaded when the cutting blade 13 is released from the operating position P1 into the resting position P2, the restoring force exerted by the spiral spring 38 is so small that it has no significant influence on the buckling force FN and the force required for triggering the cutting blade overload protection device 10

(29) The toggle lever mechanism 14 also has a spring element 19, which in the shown exemplary embodiments is integrated in the toggle lever 17. The two toggle levers 16 and 17 as well as the related components are shown in FIG. 8 and FIG. 9. The toggle lever 16 includes the two swivel joints 49 and 57 as well as an inclined plane 28, which forms a contact area 27 for the limit stop 24. The toggle lever 17 includes the two individual components 29 and 30 as well as two outer spring retaining bolts 59 and a middle spring guide bolt 60. The spring guide bolt 60 forms a guide means 36 and prevents a lateral bulging out of the spring element 19 when a load is applied.

(30) In the shown exemplary embodiments, two cylindrical plastic blocks 32 are provided for each of the two spring retaining bolts 59 and can be attached to the spring retaining bolts 59 by means of a bore hole in the blocks. Two plastic blocks 32 form an individual spring 33 and two further plastic blocks 32 form an individual spring 34. Three spacer disks 61 can also be attached.

(31) The shown embodiment with a plurality of spring retaining bolts 60 and respectively two plastic blocks 32 attachable thereto has the advantage that when the spring element 19 is compressed, not a single bulge is formed that would otherwise take up more installation space. Instead, the compression is uniformly transmitted to all plastic blocks 32 and each individual plastic block 32 bulges on its own, with the individual bulges of the four plastic blocks 32 provided in the exemplary embodiment being significantly smaller that the bulging of a larger single block—as an alternative to the four individual plastic blocks 32. In order to achieve a controlled bulging of the plastic blocks 32 in the central region, the spacer disks 61 have depressions 63 adapted to the ends of the plastic blocks 32. In their assembled state, the plastic blocks 32 are inserted in the depressions 63 and are thereby supported at their marginal regions. The depressions 63 can, for example, be screwed or embossed into the spacer disks 61.

(32) The toggle lever 17 is held together in that the guide bolt 60 provided with a screw thread 62 is inserted in a bore hole provided in the toggle lever piece 29 and, after the insertion of a washer 48, is screwed on with a nut 47. Guide bolt 60 and nut 47 thus form a tensioning device 35. Depending on how far the nut 47 is screwed on the thread 62 of the guide bolt 60, the plastic blocks 32 are prestressed to a greater or lesser extent. By prestressing the plastic blocks 32, it is possible to compensate for the greater or lesser plastic setting behavior characteristic of the selected plastic. Furthermore, the prestressing represses bothersome rattling noises during transport of the harvester 100.

(33) The washer 48 can in addition be configured as a damping element in order to reduce the noise and system stresses which occur when the spring element 19 springs back from a loaded position into its initial position.

(34) The toggle lever 17 is thus an assembly in which the spring element 19 is integrated. Analogous to toggle lever 16, the toggle lever 17 has two swivel joints, namely a swivel joint 58 and—in common with toggle lever 16—the toggle lever swivel joint 49. The toggle lever swivel joints 49 of toggle levers 16 and 17 are coupled to one another by a hinge bolt 46 and share the toggle lever rotational axis 15.

(35) FIGS. 4 to 7 show the same exemplary embodiment as in FIG. 3. FIG. 4 shows the harvester front section with the toggle lever mechanism 14 in its straight position 22, while FIG. 5 in turn shows a detached view of the toggle lever mechanism of FIG. 4. In this exemplary embodiment, the three joints 49, 57 and 58 lie on a straight line 39. The angle β2 of the two toggle levers 16 and 17 is 180°. This position represents a dead center position 20, in which the force acting on the toggle lever mechanism 14 is completely transmitted to the spring element 19.

(36) As shown in FIG. 5 in particular, the force FR, or its force component FK, has compressed the spring element 19 and thus the toggle lever 17 to a length L2. Due to the compression of the toggle lever 17 and the force component FK of force vector FR exerted on the limit stop 24 during the compression, the direction of the force vector FR and/or the toggle lever 16, controlled by the inclined plane 28, is moved such that the toggle lever rotational axis 15 is shifted to the straight line 39 (see FIG. 5). The limit stop 24 and inclined plane 28 thus form a compulsory guide for the shifting of the toggle lever rotational axis 15.

(37) FIG. 6 shows the front section of the harvester with the toggle lever mechanism 14 in its second buckling position 23, while FIG. 7 shows the detached view of the toggle lever mechanism 14 of FIG. 6. The cutting blade 13 is located in a resting position P2 swung out of the conveyor channel 45. The cutting blade is not pressed out of the conveyor channel 45 by the foreign object 50 relatively slowly but is rather catapulted out of the conveyor channel 45 by the abruptly released energy of the previously compressed spring element 19 after the dead center point 20 has been passed.

(38) The inclined plane 28 is thus sufficient for the toggle lever 16, and with it the toggle lever rotational axis 15, with the slightest additional application of force in the dead center position 20 to be guided beyond the dead center point. The triggering of the blade protection device is thus caused by a change of direction of the force component FN: In the case of a force acting on the cutting blade and causing a torque M, which causes a force FR to be exerted on the toggle lever mechanism 14 that is smaller than the predefined force F1, the resultant force FR acting on the toggle lever mechanism 14 has a force component FN acting in the pressure buckling direction R3. As the applied force increases, the magnitude of force FN decreases.

(39) If the force FR acting on the toggle lever mechanism 14 achieves the predefined value F1, the buckling force acting in the direction R2 or R3 measures zero Newtons. A further increase in the force acting on the cutting blade 13, and thus an accompanying increase in the torque M as well as in the force FR acting on the toggle lever mechanism 14, causes the force component FN to reverse its effective direction from the pressure buckling direction R3 to the deflection buckling direction R2 and the cutting blade 13 is swung out of the operating position P1 into the resting position P2.

(40) In the exemplary embodiment shown in FIGS. 2 to 7, the angle between the two toggle levers 16 and 17 is reduced, at first from the initial value present at the first buckling position 21, which is greater than 180° (overextended position), to 180° (dead center position) and upon passing the dead center position during the transition to a second buckling position 23 to less than 180°. Upon release, the spring element 19 and the counterforce to force vector FR resulting from its compression no longer exerts pressure in the direction R3, and thus against the cutting blade 13 in the tendency to keep the latter held in the conveyor channel 45. Instead, the spring element 19 lets the toggle lever mechanism 14 buckle without resistance about the toggle lever rotational axis 15 in the direction R2. The buckled position of the toggle lever mechanism 14 thus represents the second buckling position 23 in which the spring element 19 reverts to its relaxed initial position and the toggle lever 17 has again assumed its original length L1. After blade protection has been triggered, the angle β1 present in the first buckling position 21 is reduced in the second buckling position to an angle β3, which is significantly less than 180°, in the exemplary embodiment it has an angle of approximately 100°.

(41) Also shown in FIG. 6 is that the position of foreign object 50 present in the harvested material (not shown) has not changed relative to the feed tines 42. After the cutting blade 13 has been swung out, the foreign object 50 is further conveyed along with the harvested material in the direction of the loading space 53, since the cutting blade 13 deflected out of the conveyor channel 45 has provided the necessary space for this. This is meant to illustrate that, after making contact with the cutting blade 13, the foreign object 50 is not scraped along the cutting blade of the latter but instead has provided that the cutting blade 13 is catapulted out of the conveyor channel 45.

(42) In order to swing the cutting blade 13 counter to the direction R1 from its resting position P2 back into the conveyor channel 45 and thus into its operating position P1, the spring element 19 does not have to be compressed so long as no counterforce presses against the cutting blade 13. It is sufficient to introduce a slight force to the toggle lever mechanism 14 oriented in the direction R3 and the toggle lever swivel joint 49 is drawn by this force through the straight position 22 and back into the first buckling position 21. In the shown exemplary embodiment, this restoring force is supplied by a spiral spring 38 as the restoring means 37. The spiral spring 38 is coupled at one of its ends to the toggle lever mechanism 14 in the region of the toggle lever swivel joint 49 and at its other end to the supporting structure 55. As an alternative to a spiral spring, it is possible to provide a roller spring, a rubber band or an elastic band.

(43) FIGS. 10 to 13 illustrate the cutting blade overload protection device 10 of the invention. The angle β1 between the two toggle levers is greater than 180° and the two toggle levers assume an overextended position in operating position P1.

(44) Thus, the angle β1 in the first buckling position 21 can be greater than 180°.

(45) The toggle lever mechanism 14 is guided out of a first buckling position 21 provided in operating position P1, through a dead center position and into the resting position P2, and thus into a second buckling position 23. The dead center position 20 is located in a straight position of the two toggle levers 16 and 17. The dead center position 20 is defined such that the buckling force at the dead center position measures zero Newtons. The rotational axis 15 of the toggle lever swivel joint 49 lies in the dead center position on the straight line 39.

(46) FIGS. 10 to 13 also illustrate the forces acting in the toggle lever mechanism when different loads are applied on the cutting blade 13 in each case. During harvesting operations, the harvested material conveyed by the rotor 40 (see FIG. 1) in front of the cutting blade exerts a force FE on the cutting blade 13. In FIGS. 10 to 12, the force FE is indicated in the form of small force vectors which impact the cutting blade 13 on its cutting edge. Also shown is a foreign object 50 located in the harvested material (see also FIG. 2 and FIG. 4), which exerts a force FFK on the cutting blade. The forces FFK and FE together effect the torque M about the rotational axis 12 of the cutting blade 13. The torque M transfers a force FR to the toggle lever mechanism. The magnitude of force FR is thus dependent on the magnitude of torque M or the forces FFK and FE which give rise to the torque M.

(47) FIG. 10 shows a schematic view of a first state in which the force FR acting on the toggle lever mechanism 14 is smaller than the predefined force F1 for triggering the cutting blade overload protection 10.

(48) Inasmuch as a restoring means 37 is provided in the form of a return spring (indicated in FIG. 13), it exerts an additional force in the toggle lever swivel joint 49 acting in the direction R3. This restoring force, where appropriate, can be included and taken into account in the design of the components and the preselection, or predefinition, of the triggering force F1, with the result that the restoring force of the return spring exerts no disruptive influence on the triggering of the cutting blade overload protection device 10.

(49) FIG. 11 shows a second state in which the force FR acting on the toggle lever mechanism 14 corresponds to the predefined triggering force F1. The force FR introduced to the toggle lever mechanism 14 by the torque M can be designated as force FR′ at the points P02 and as force FR″ at point P03. The system is in the dead center position 20. In this position, the total force FR is introduced to the toggle lever 17 as compression force and compresses the spring element 19.

(50) FIG. 12 shows a third state in which the force FR acting on the toggle lever mechanism 14 is further increased and has exceeded the magnitude of the predefined release force F1. This third state is unstable and therefore passes to the fourth state shown in FIG. 13 without further action. The force FR now no longer has any counterbearing at point P02 and is not supported at this point. Instead, the force FR is transmitted as force FR″ to the point P03 and the toggle lever swivel joint 49, and has a force component FDY directed in the deflection buckling direction R2. If no restoring means 37 are provided, or if no force is transmitted to the toggle lever swivel joint 49 by a restoring means acting in the direction R3, a minimal force component FDY oriented in the direction R2 is sufficient to trigger the cutting blade overload protection device 10. The triggering action is supported by the spring element 19, which is preloaded by the compression force FK and which relaxes when the dead center position 20 is passed. Here the energy stored in the spring element 19 is released abruptly, catapulting the cutting blade into its resting position P2.

(51) FIG. 13 shows a fourth state in which the cutting blade 13 has been swung out of the conveyor channel and now assumes the resting position P2. The cutting blade 13 is not subjected to any load by either the harvested material or a foreign object. Inasmuch as no restoring means 37 is provided, no torque is exerted about the cutting blade rotational axis 12. If a restoring means 37 is provided, for example in the form of a spiral spring which acts on the toggle lever mechanism 14 in the region of the toggle lever swivel joint 49, torque is exerted about the cutting blade rotational axis 12, which swings the cutting blade 13 back into its operating position P1. In FIG. 13 such a restoring means is represented in an exemplary and suggestive manner. It can be seen that in the fourth state shown in FIG. 13, no force acts at point P01. Nor is there any force acting on the toggle lever swivel joint 49 and in the spring element 19. Instead, the entire toggle lever mechanism is in a relaxed position. In order to pivot the toggle lever swivel joint 49 in the direction R3, only the frictional forces inherent in the system must be overcome, or the system's components must be moved upward against the gravitational force exerted by these parts.

LIST OF REFERENCE NUMBERS

(52) 10 cutting blade overload protection device

(53) 11 cutting mechanism

(54) 12 cutting blade rotational axis

(55) 13 cutting blade

(56) 14 toggle lever mechanism

(57) 15 toggle lever rotational axis

(58) 16 toggle lever

(59) 17 toggle lever

(60) 18 guide element

(61) 19 spring element

(62) 20 dead center position

(63) 21 first buckling position

(64) 22 straight position

(65) 23 second buckling position

(66) 24 limit stop

(67) 25 contour

(68) 26 -

(69) 27 contact area

(70) 28 inclined plane

(71) 29 individual component

(72) 30 individual component

(73) 31 supporting frame

(74) 32 plastic block

(75) 33 individual spring

(76) 34 individual spring

(77) 35 tensioning device

(78) 36 guide means

(79) 37 restoring means

(80) 38 spiral spring

(81) 39 straight line

(82) 40 feed rotor

(83) 41 supporting tube

(84) 42 feed tine

(85) 43 external cylinder

(86) 44 conveyor trough

(87) 45 conveyor channel

(88) 46 hinge bolt

(89) 47 nut

(90) 48 washer

(91) 49 toggle lever swivel joint

(92) 50 foreign object

(93) 51 reel

(94) 52 tine tip

(95) 53 loading space

(96) 54 blade holder

(97) 55 supporting structure

(98) 56 rotational axis (of 11)

(99) 57 swivel joint (of 16)

(100) 58 swivel joint (of 17)

(101) 59 spring retaining bolt

(102) 60 guide bolt

(103) 61 spacer disk

(104) 62 screw thread

(105) 63 depression (in 61)

(106) 100 harvester

(107) 157 pivot axis (of 57)

(108) 158 pivot axis (of 58)

(109) P1 operating position

(110) P2 resting position

(111) P01 contact point (of 13 and 16)

(112) P02 contact point (of 24 and 16)

(113) P03 contact point (of 16 and 17)

(114) F force (acting on 14)

(115) F1 force (triggering force)

(116) FE force (exerted by harvested material)

(117) FN force (buckling force)

(118) FK force (compression force)

(119) FFK force (exerted by foreign object 50)

(120) FDY force (applied in 49)

(121) FR force (resultant force in P01)

(122) FR′ force (resultant force in point P02)

(123) FR″ force (resultant force in point P03)

(124) L1 length

(125) L2 length

(126) M torque (about 12)

(127) R1 direction

(128) R2 direction

(129) R3 direction

(130) β1 angle in first buckling position 21

(131) β2 angle in straight position 22

(132) β3 angle in second buckling position 23