Assignee
Inventors
- Willem Griffioen (48 patents)
- Arie Van Wingerden (10 patents)
- Unknown
- Pieter Lock (12 patents)
- Willem Greven (10 patents)
- Frans Robbert Bakker (6 patents)
- David Frederick Hawkins (5 patents)
US Patent 6619697 · Granted Sep 16, 2003