A sickle cutting system is mounted on a header for forward travel over ground having a standing crop thereon and includes a cutter bar with a plurality of knife guards and two sickle bars driven at a phase angle difference where the drive system has a phase difference control component operable to drive the first and second sickle bars at a first phase angle difference typically at or around 180 degrees difference to minimize vibration when no cutting action is occurring and at a second phase angle difference which can be at or around 90 degrees to minimize variations in loading applied to the drive system when the cutting action is taking place.

A self-propelled work apparatus, especially a lawnmower, includes a chassis, at least one tool and a drive motor for driving the tool. The tool is height-adjustable with respect to the chassis. A setting unit is provided to set the relative position of the tool with respect to the chassis. The setting unit includes an actuating motor and a setting gear. The setting gear rotates by less than one full revolution between a first, lower end position of the tool and a second, upper end position of the tool. A detection device is provided to detect the height position of the tool. The detection device includes encoding elements on the setting gear and at least one detector. The at least one first encoding element for the first end position differs from the at least one second encoding element for the second end position.

A self-propelled work apparatus, especially a lawnmower, includes a chassis, at least one tool and a drive motor for driving the tool. The tool is height-adjustable with respect to the chassis. A setting unit is provided to set the relative position of the tool with respect to the chassis. The setting unit includes an actuating motor and a setting gear. The setting gear rotates by less than one full revolution between a first, lower end position of the tool and a second, upper end position of the tool. A detection device is provided to detect the height position of the tool. The detection device includes encoding elements on the setting gear and at least one detector. The at least one first encoding element for the first end position differs from the at least one second encoding element for the second end position.

A knife drive assembly for use in a harvesting header may be mounted near the center line of the cutter bar of the header. Mechanical power from the power unit behind the header (typically the combine power output shaft) may be translated for application to two knife assembly sections in the cutter bar at the front of the cutter table. Movement of the two knife assembly sections with this apparatus can be fully synchronized and 180 degrees out of phase, to maximize cutting effectiveness and minimize vibration of the header. The unitary drive assembly may allow for rapid repair and manufacture, and the size and weight of the knife drive assembly may represent a significant weight and balance advantage over the prior art.

The present invention relates to cutting tools, in particular, to control systems for cutters such as vegetation cutters, especially hedge cutters or trimmers (10). Hedge cutters (10) frequently suffer in use from a problem of blocked cutting blades when they encounter a twig or branch whose size or density exceeds the capacity of the blades. We describe a vegetation cutting apparatus (10) having a plurality of cutting blades (11,12), at least one of which blades (11,12) is drivable by an electric motor. At least one driven blade (11,12) is movable between two predefined points of maximum travel. The apparatus (10) includes a control mechanism which causes a change of direction in the movement of the at least one movable blade at a point intermediate the points of maximum travel in response to an event sensed by the control mechanism.

The present invention relates to cutting tools, in particular, to control systems for cutters such as vegetation cutters, especially hedge cutters or trimmers (10). Hedge cutters (10) frequently suffer in use from a problem of blocked cutting blades when they encounter a twig or branch whose size or density exceeds the capacity of the blades. We describe a vegetation cutting apparatus (10) having a plurality of cutting blades (11,12), at least one of which blades (11,12) is drivable by an electric motor. At least one driven blade (11,12) is movable between two predefined points of maximum travel. The apparatus (10) includes a control mechanism which causes a change of direction in the movement of the at least one movable blade at a point intermediate the points of maximum travel in response to an event sensed by the control mechanism.

The cutter bar of a header including two sickle bars is driven by a center drive system including a rotary input drive member driven by a motor, first and second rotary members each driven by the drive member about a generally upstanding first rotational axis. Each of the rotary members has an eccentric drive system for driving a respective sickle bar. A flywheel is driven by the rotary input drive member for common rotation therewith and the first and second rotary members are driven by a common drive sprocket to rotate in the same direction about the first and second rotary axes.

The cutter bar of a header including two sickle bars is driven by a center drive system including a rotary input drive member driven by a motor, first and second rotary members each driven by the drive member about a generally upstanding first rotational axis. Each of the rotary members has an eccentric drive system for driving a respective sickle bar. A flywheel is driven by the rotary input drive member for common rotation therewith and the first and second rotary members are driven by a common drive sprocket to rotate in the same direction about the first and second rotary axes.

A timing apparatus for sickle knives having adjacent knife ends, respectively, having an endless elongate element encircling and movable about spaced apart support elements such that first and second portions of the elongate element span a space between the support elements, and connector elements connecting the knife ends to the first and second portions of the elongate element, respectively, such that movement of the elongate element in a first direction about the support elements will move the knives in timed relation in first opposite cutting directions, and movement of the elongate element in a second direction opposite the first direction will move the knives in timed relation in second opposite cutting directions. The apparatus can be connected between separately drive knives for timing their motions, or for using one of the knives for timingly driving another of the knives.

A timing apparatus for sickle knives having adjacent knife ends, respectively, having an endless elongate element encircling and movable about spaced apart support elements such that first and second portions of the elongate element span a space between the support elements, and connector elements connecting the knife ends to the first and second portions of the elongate element, respectively, such that movement of the elongate element in a first direction about the support elements will move the knives in timed relation in first opposite cutting directions, and movement of the elongate element in a second direction opposite the first direction will move the knives in timed relation in second opposite cutting directions. The apparatus can be connected between separately drive knives for timing their motions, or for using one of the knives for timingly driving another of the knives.