Belt-type cutting system for cutting crops in a field
The cutting system includes knives attached to a continuously moving belt-type carrier. The carrier motion moves the knives past stationary counterknife fingers. Each knife is pivotably connected to the platform portion of a support bracket having also a wall portion that is fixed to the belt-type carrier. The knife is furthermore coupled to the bracket by a reversible force coupling that maintains the knife in a forwardly oriented operational position when the knife is subjected to lateral forces which exert a torque on the knife that remains below a predefined limit, encountered when the knife is cutting stalks or meeting small obstructions. When the knife is subjected to lateral forces resulting in a torque above the predefined limit, the force coupling is configured to be disengaged in a reversible manner, enabling the knife to pivot about a rotation axis towards a non-operational position.
1 . A cutting system configured to be driven through a field in a forward direction in order to cut plant stalks at a given distance from the ground, the cutting system comprising:
(i) a belt-type carrier configured to be guided by a set of pulleys, so as to move in a direction transversal to the stalks, wherein a plurality of knives are attached to a lateral surface of the carrier,
(ii) a cutterbar provided with a plurality of counterknives configured to remain stationary relative to the knives as the knives move past the counterknives, to thereby cut the stalks,
each knife being attached to the carrier through a support bracket, the support bracket comprising a wall portion that is fixed to the carrier and a platform portion extending outward from the carrier,
each knife being pivotably coupled to the platform portion of the bracket,
each knife being pivotable about a rotation axis, which is substantially perpendicular to the platform portion, between an operational position in which the knife is oriented in a forward direction and a non-operational position in which the knife is pivoted away from the forward direction,
the knife being coupled to the bracket by a reversible force coupling that (i) maintains the knife in the operational position when the knife is cutting plant stalks, and (ii) requires a predefined torque in order to disengage the coupling and thereby allow the knife to pivot about the rotation axis towards the non-operational position, and
(iii) at least one reset element that is configured to interact with the reversible force couplings of the knives to thereby automatically reset the knives from the non-operational position back to the operational position.
2 . The cutting system according to claim 1 wherein the reversible force coupling comprises at least one spring configured to apply a spring force that maintains the knife in said operational position unless a lateral force is executed that results in a torque higher than the predefined torque.
3 . The cutting system according to claim 2 , wherein the spring is a leaf spring mounted underneath the platform portion of the bracket, wherein a releasable retention mechanism is mounted between the leaf spring and the knife and wherein the spring force is generated by inserting a shaft of a bolt through a central opening of the leaf spring, through an opening in the platform portion and through an opening in the knife, and by tightening a nut onto the end of the shaft, thereby activating the releasable retention mechanism so that said releasable retention mechanism maintains the knife in the operational position.
4 . The cutting system according to claim 3 , wherein the retention mechanism comprises a retention block that is non-rotatably connected to the knife, and that is coupled to the platform portion of the bracket or to a holding element fixed thereto by a releasable interface that requires the retention block to be pushed downward against the spring force in order for the interface to be released.
5 . The cutting system according to claim 4 , wherein the releasable interface comprises slanted clutch portions which interlock when the knife is in the operational position, and which are forced to slide past each other when the knife is pivoted towards the non-operational position.
6 . The cutting system according to claim 4 , wherein the releasable interface comprises latch pins having rounded tips which are inserted in corresponding seat portions when the knife is in the operational position, and which are forced to slide out of the seat portions when the knife is pivoted towards the non-operational position.
7 . The cutting system according to claim 3 , wherein the retention mechanism comprises latch pins having rounded tips which are inserted into openings disposed in the knife on either side of the rotation axis, said latch pins being slidably inserted in openings disposed in the platform portion of the bracket, said pins being furthermore maintained in the openings of the knife by the leaf spring when the knife is in the operational position.
8 . A cutting system configured to be driven through a field in a forward direction in order to cut plant stalks at a given distance from the ground, the cutting system comprising:
a belt-type carrier configured to be guided by a set of pulleys, so as to move in a direction transversal to the stalks, wherein a plurality of knives are attached to a lateral surface of the carrier, and
a cutterbar provided with a plurality of counterknives configured to remain stationary relative to the knives as the knives move past the counterknives, to thereby cut the stalks,
each knife being attached to the carrier through a support bracket, the support bracket comprising a wall portion that is fixed to the carrier and a platform portion extending outward from the carrier,
each knife being pivotably coupled to the platform portion of the bracket,
each knife being pivotable about a rotation axis, which is substantially perpendicular to the platform portion, between an operational position in which the knife is oriented in a forward direction and a non-operational position in which the knife is pivoted away from the forward direction,
the knife being coupled to the bracket by a reversible force coupling that (i) maintains the knife in the operational position when the knife is cutting plant stalks, and (ii) requires a predefined torque in order to disengage the coupling and thereby allow the knife to pivot about the rotation axis towards the non-operational position,
wherein the first and second knife of any pair of adjacent knives are pivotably coupled to the same support bracket,
wherein said reversible force coupling acts directly on the first of said pair of adjacent knives, and
wherein the second of said pair of adjacent knives is coupled to the first knife through a link that allows only a simultaneous pivoting motion of the first and second knife about their respective rotation axes.
9 . A cutting system configured to be driven through a field in a forward direction in order to cut plant stalks at a given distance from the ground, the cutting system comprising:
a belt-type carrier configured to be guided by a set of pulleys, so as to move in a direction transversal to the stalks, wherein a plurality of knives are attached to a lateral surface of the carrier, and
a cutterbar provided with a plurality of counterknives configured to remain stationary relative to the knives as the knives move past the counterknives, to thereby cut the stalks,
each knife being attached to the carrier through a support bracket, the support bracket comprising a wall portion that is fixed to the carrier and a platform portion extending outward from the carrier,
each knife being pivotably coupled to the platform portion of the bracket,
each knife being pivotable about a rotation axis, which is substantially perpendicular to the platform portion, between an operational position in which the knife is oriented in a forward direction and a non-operational position in which the knife is pivoted away from the forward direction,
the knife being coupled to the bracket by a reversible force coupling that (i) maintains the knife in the operational position when the knife is cutting plant stalks, and (ii) requires a predefined torque in order to disengage the coupling and thereby allow the knife to pivot about the rotation axis towards the non-operational position,
wherein the force coupling comprises an overcenter mechanism.
10 . The cutting system according to claim 9 , wherein two adjacent knives are pivotably connected to the platform portion of a single bracket, and wherein an overcenter link is furthermore pivotably coupled to the two adjacent knives at pivot points which are located such that the knives are locked into the operational position unless a lateral force is applied to at least one of the two knives, said lateral force resulting in a torque that is equal to or higher than the predefined torque.
11 . The cutting system according to claim 1 , wherein the reset element is a cam element and wherein the reversible force coupling comprises a retention block, configured to interact with the cam element to thereby reset the knife back to the operational position.
12 . The cutting system according to claim 11 , wherein a position of the cam element is adjustable.
13 . A header for an agricultural implement comprising the cutting system according to claim 1 .
14 . A combine harvester comprising the cutting system according to claim 1 .