Granted Patent
Utility
US 6,687,953 · App. 09/689,853
Torsion spring door check device
Inventor:
Chuan-Yi Liang
Patented Case
View Patent ↗
Granted: Feb 10, 2004
Filed: Oct 13, 2000
Inventor
Chuan-Yi Liang
Assignee (at issue)
VENTRA GROUP CO.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.