Abstract: A header is supported by a pair of hydraulic float cylinders, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration and/or velocity. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. A lift force greater than that required to lift the header can be provided by a lift cylinder and can be opposed in a controlled manner to apply a controlled downforce by the back of the same cylinder or by a separate component.

Abstract: In a crop harvesting machine there is provided a pair of hydraulic float cylinders or springs for a header such as a rotary mower relative to a self-propelled vehicle, where a float spring force is controlled to provide a predetermined lifting force is provided to the header. The spring force is varied in response to detection of ground speed to decrease the lifting force at higher ground speeds. A position sensor is used to generate an indication of movement and/or acceleration. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. In order to reduce static friction so that the system can react quickly, an arrangement is provided for causing relative reciprocating movement in an alternating wave pattern between the piston and cylinder.

Abstract: A header is supported by a pair of hydraulic float cylinders, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration and/or velocity. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. A lift force greater than that required to lift the header can be provided by a lift cylinder and can be opposed in a controlled manner to apply a controlled downforce by the back of the same cylinder or by a separate component.

Abstract: A header is supported by a pair of hydraulic float cylinders, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration and/or velocity. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. A lift force greater than that required to lift the header can be provided by a lift cylinder and can be opposed in a controlled manner to apply a controlled downforce by the back of the same cylinder or by a separate component.

Abstract: A header is supported by a pair of hydraulic float cylinders, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration and/or velocity. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. A lift force greater than that required to lift the header can be provided by a lift cylinder and can be opposed in a controlled manner to apply a controlled downforce by the back of the same cylinder or by a separate component.

Abstract: A header is supported by a pair of hydraulic float cylinders, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration and/or velocity. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. A lift force greater than that required to lift the header can be provided by a lift cylinder and can be opposed in a controlled manner to apply a controlled downforce by the back of the same cylinder or by a separate component.

Abstract: In a crop harvesting machine there is provided a pair of hydraulic float cylinders or springs for a header such as a rotary mower relative to a self-propelled vehicle, where a float spring force is controlled to provide a predetermined lifting force is provided to the header. The spring force is varied in response to detection of ground speed to decrease the lifting force at higher ground speeds. A position sensor is used to generate an indication of movement and/or acceleration. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. In order to reduce static friction so that the system can react quickly, an arrangement is provided for causing relative reciprocating movement in an alternating wave pattern between the piston and cylinder.

Abstract: 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 opposed sickle bars driven in opposite phase with a drive system for driving the sickle bar through repeated cycles of reciprocating movement from start-up of the system through to a shut-down. The drive system includes a control device responsive to the sensor signals from both of the first and second drive systems for advancing or retarding one of the first and second drive systems so that a number of sensor signals obtained from the first drive system is continually maintained so as to be substantially equal to a number of sensor signals obtained from the second drive system to maintain the sickle bars in opposite phase.

Abstract: A header is supported by a pair of hydraulic float cylinders, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration and/or velocity. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. A lift force greater than that required to lift the header can be provided by a lift cylinder and can be opposed in a controlled manner to apply a controlled downforce by the back of the same cylinder or by a separate component.

Abstract: A header is supported by a pair of hydraulic float cylinders, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration and/or velocity. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. A lift force greater than that required to lift the header can be provided by a lift cylinder and can be opposed in a controlled manner to apply a controlled downforce by the back of the same cylinder or by a separate component.

Abstract: A header is supported by a pair of hydraulic float cylinders, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration and/or velocity. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. A lift force greater than that required to lift the header can be provided by a lift cylinder and can be opposed in a controlled manner to apply a controlled downforce by the back of the same cylinder or by a separate component.

Abstract: In a crop harvesting machine there is provided a pair of hydraulic float cylinders for a header relative to a vehicle, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. In order to reduce static friction so that the system can react quickly, an arrangement is provided for causing relative reciprocating movement in an alternating wave pattern between the piston and cylinder.

Abstract: In a crop harvesting machine there is provided a pair of hydraulic float cylinders for a header relative to a vehicle, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. In order to reduce static friction so that the system can react quickly, an arrangement is provided for causing relative reciprocating movement in an alternating wave pattern between the piston and cylinder.

Abstract: In a crop harvesting machine there is provided a pair of hydraulic float cylinders for a header relative to a vehicle, where a float pressure to the cylinders is directly controlled by an electronic control supplying a variable control signal to a PPRR valve arrangement to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header. A position sensor is used to generate an indication of movement and/or acceleration. The electronic control is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder. In order to reduce static friction so that the system can react quickly, an arrangement is provided for causing relative reciprocating movement in an alternating wave pattern between the piston and cylinder.

Abstract: 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 opposed sickle bars driven in opposite phase with a drive system for driving the sickle bar through repeated cycles of reciprocating movement from start-up of the system through to a shut-down. The drive system includes a control device responsive to the sensor signals from both of the first and second drive systems for advancing or retarding one of the first and second drive systems so that a number of sensor signals obtained from the first drive system is continually maintained so as to be substantially equal to a number of sensor signals obtained from the second drive system to maintain the sickle bars in opposite phase.