Windrower header speed control
US6167685A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 24, 1999 |
| Grant date | Jan 2, 2001 |
| Priority date | — |
| Expiry date | Mar 24, 2019 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA01D41/142
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A system for controlling the header speed of a windrower to a set point includes a variable displacement pump producing a variable outflow of hydraulic fluid for driving the header via two hydraulic motors, the system being characterized in that the pump is driven by a pulse width modulated (PWM) signal having a duty cycle that is dependent on the speed and the acceleration of the header. When the header speed falls outside a window or range of speeds centered at the set point, header speed is used to modify the duty cycle of the PWM signal and bring the header speed back within the window. In addition, the duty cycle of the PWM signal is decremented if the acceleration of the header exceeds a threshold and the header includes disk type cutters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.