Low profile sickle drive

A sickle drive comprising;

• an enclosure including a generally flat upper cover having a forward end disposed just rearwardly of a sidewardly extending sickle of a header of an agricultural plant cutting machine, and a lower cover which tapers or curves upwardly from a lowermost rear end toward a forward end thereof which connects with the forward end of the upper cover defining a cavity therebetween;
• an epicyclic drive mechanism including a rotatable first input element supported in the cavity for rotation about a generally upstanding first rotational axis, a first eccentric element supported in the cavity in connection with the first input element for rotation thereby along a first epicyclic orbit about the first rotational axis, the first eccentric element having a generally upstanding first eccentric axis laterally offset relative to the first rotational axis, a first drive arm disposed in the cavity and having a first end connected to the eccentric element for rotation about the first eccentric axis and eccentric rotation with the eccentric element about the first rotational axis, the first drive arm extending in a first sideward direction to a second end pivotally connected to a pivot arm of a pivot element eccentric about a shaft of the pivot element supported for rotation about a generally upstanding first pivotal axis therethrough extending upwardly through an aperture in the upper cover, such that the shaft will be pivoted about the first pivotal axis by the rotation of the first end of the drive arm;
• a second epicyclic drive mechanism including a rotatable second input element supported in the cavity for rotation about a generally upstanding second rotational axis, a second eccentric element supported in the cavity in connection with the second input element for rotation thereby along a second epicyclic orbit about the second rotational axis, the second eccentric element having a generally upstanding second eccentric axis laterally offset to the second rotational axis, a second drive arm disposed in the cavity and having a first end connected to the second eccentric element for rotation about the second eccentric axis and eccentric rotation about the second rotational axis, the second drive arm extending in a second sideward direction opposite the first sideward direction to a second end pivotally connected to a second pivot arm of a second pivot element eccentric about a shaft of the second pivot element supported for rotation about a generally upstanding second pivotal axis therethrough extending upwardly through an aperture in the upper cover, such that the second shaft will be pivoted about the second pivotal axis by the rotation of the first end of the second drive arm, and a second knife arm mounted on the second shaft above the upper cover of the enclosure and connecting to a second knife assembly of the sickle, for reciprocatingly moving the second knife assembly sidewardly relative to the enclosure;
• and
• a first knife arm mounted on the shaft of the pivot element above the upper cover of the enclosure and connecting to a first knife assembly of the sickle, for reciprocatingly moving the first knife assembly sidewardly relative to the enclosure,
• wherein the first drive arm extends sidewardly, across and forwardly of the second input element, and the second drive arm extends sidewardly, across and rearwardly of the first input element.

A header for a plant cutting machine comprising:

• a generally flat cover or floor having a forward end and bounding and defining an upper region of a generally flat cavity rearwardly of a forward end of the machine;
• and
• a sickle drive disposed below the generally flat cover or floor, the sickle drive including:
• a first sickle knife assembly supported for side to side reciprocating movement along the forward end of the machine,
• a rotary power input for driving the first sickle knife assembly
• a rotatable first input element supported in the cavity for rotation about a generally upstanding first rotational axis by the rotary power input,
• a rotatable second input element supported in the cavity adjacent to the first input element for rotation about a generally upstanding second rotational axis by the rotary power input,
• a first eccentric element in connection with the first input element for rotation thereby in eccentric relation to the first rotational axis about a generally upstanding first eccentric axis laterally offset relative to the first rotational axis,
• a second eccentric element in connection with the second input element for rotation thereby in eccentric relation to the second rotational axis about a generally upstanding second eccentric axis laterally offset relative to the second rotational axis,
• a first drive arm having a first end and a second end opposite the first end, the first end being connected to the first eccentric element for rotation about the first eccentric axis and eccentric rotation about the first rotational axis, the first drive arm extending in a first direction from the first end to the second end, the second end pivotally connecting eccentrically to a first pivot element supported for rotation about a generally upstanding first pivotal axis, such that the first pivot element will be pivoted about the first pivotal axis by the rotation of the first input element about the first rotational axis, and the first pivot element being configured for connection to the first sickle knife assembly, such that the first sickle knife assembly will be reciprocatingly moved relative to the drive by the pivoting of the first pivot element, and
• a second drive arm having a first end and a second end opposite the first end, the first end of the second drive arm being connected to the second eccentric element for rotation about the second eccentric axis and eccentric rotation about the second rotational axis, the second drive arm extending in a second direction from the first end thereof to the second end thereof, the second end of the second drive arm pivotally connecting eccentrically to a second pivot element supported for rotation about a generally upstanding second pivotal axis, such that the second pivot element will be pivoted about the second pivotal axis by the rotation of the second input element about the second rotational axis, and the second pivot element being configured for connection to a second sickle knife assembly, such that the second sickle knife assembly will be reciprocatingly moved relative to the drive by the pivoting of the second pivot element,
• wherein the first drive arm extends sidewardly within a forward portion of the cavity generally forwardly of and across the second input element, and the second drive arm extends sidewardly within a rear portion of the cavity generally rearwardly of and across the first input element.