Engine-sensing draft control system with multiple feedback compensation mechanisms
US4846283A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 8, 1987 |
| Grant date | Jul 11, 1989 |
| Priority date | — |
| Expiry date | Sep 8, 2007 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02F9/2029
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An automatic feedback control system for use with an off-road vehicle having an adjustable-elevation, ground-engaging implement, such as an agricultural tractor with a three-point hitch and a plough or cultivator, is disclosed. The automatic control system provides an engine-sensing draft control system which adjusts the height or elevation of the ground-engaging implement so as to maintain the draft or load forces experienced by the vehicle at a substantially constant level. The determination of the draft being produced by the ground-engaging implement is determined by the engine speed deviation from a target point speed which is indicated by an operator-set desired no-load engine speed and an operator-set engine lug-down value or load. To provide proper operation of the engine-sensing draft control system, multiple feedback compensation mechanisms are provided, including a throttle compensation function, an electrohydraulic valve compensation function, a slip-sensing function, a sensitivity (deadband) adjustment, a maximum implement-lowering rate function, and an automatic downshift signal function to cause the transmission of the tractor to downshift to a lower speed to avoid en…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.