Draft control system with dual mode draft sensitivity
US5143159A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1991 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Jun 3, 2011 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA01B63/112
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A tractor-mounted three-point hitch for pulling a tillage implement is controlled by a closed loop including draft sensors for sensing the draft on the hitch and providing a draft feedback signal. An operator-controlled quadrant lever provides command signals for commanding the positioning of the hitch relative to the ground. During rapid hitch movement commanded by movement of the quadrant lever while the implement is above the ground, the draft feedback signal, which is normally filtered to eliminate frequencies above about 3.2 Hz, is more heavily filtered to eliminate frequencies above 0.5 Hz. This makes the loop less sensitive to the draft feedback signal and reduces vibrations which would otherwise occur because of oscillations in the draft feedback signal. The oscillations are caused by interaction of the weight of the implement bouncing because of the pneumatic tires on the tractor, and movement of the hitch to correct for the apparent change in draft. As the hitch approaches the commanded position the system reverts to the normal filtering so that the system is more sensitive to the draft feedback signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.