Inventor
Richard A. Wittren
Inventor
Cedar Falls, IA, US
Overview
Patents· 12 as inventor
Public. Assignee & technology derived from the patent record. Each patent links to its LexDana page.
F15Bprimary
F15BSystems acting by means of fluids in general25%
B62DMotor vehicles21%
Y10TTechnical subjects covered by former us classification21%
F16HGearing17%
G05DSystems for controlling or regulating non-electric variables8%
F04BPositive-displacement machines for liquids4%
F16KValves4%
PatentTitleYear
4,640,094'Flow amplifying steering system'19874,556,078'Priority valve'19854,541,451'Priority valve'19854,463,775'Compensating valve'19844,405,030'Steering system and compensating valve'19834,367,803'Steering system'19834,209,984'Hydraulic system with unloading valve assembly'19804,170,113'Hydraulic system with unloading valve assembly'19794,066,099'Zero lap valve'19784,038,886'Forward, neutral and reverse V-belt planetary drive'19773,995,425'Demand compensated hydraulic system with pilot line pressure-maintaining valve'19763,986,438'Hydraulic cylinder with integral feedback cylinder'1976Career & activity timeline
Assembled from patent assignee/location history and declaration credentials.
1976–1987Patents assigned to DEERE & CO (12)· patent assignee history
1976–1987Based in Cedar Falls, IA, US· patent location history
Inventor activity
Assignee and location history derived from the patent record.
Assignees
| Assignee | Patents | Span |
|---|---|---|
| DEERE & CO | 12 | 1976–1987 |
Locations
| Location | Patents | Span |
|---|---|---|
| Cedar Falls, IA, US | 12 | 1976–1987 |