You can freely build on How Elmer Sperry Invented the Gyroscopic Compass for Ships
This patent expired in 1934. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Sperry Gyroscope Co Inc
Patent granted
1917
Expired
1934
Forward citations
2
What this patent covers
The patent describes a device using a rapidly spinning gyroscope to maintain a fixed orientation in space. Because the Earth rotates, a gyroscope mounted on a ship will naturally align itself with the Earth's axis, pointing toward true north rather than magnetic north. The mechanism includes a gimbal system that allows the gyroscope to remain stable even as the ship pitches and rolls on rough seas. This provides a reliable, constant heading reference that does not suffer from the interference caused by the steel hulls of modern ships.
What is now free to use
All 0 claims of US 1242065 are in the public domain. Specifically:
The 0 dependent claims add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
Does not cover magnetic compasses that rely on the Earth's magnetic field.
Does not cover electronic or GPS-based navigation systems.
Does not cover gyroscopes used for stabilization rather than directional finding.
Who is building on this today
The Sperry Gyroscope Company became a cornerstone of the defense industry, eventually merging into larger entities like Northrop Grumman. Today, companies like Honeywell and Raytheon continue to develop advanced inertial navigation systems that trace their lineage back to these fundamental principles.
Products built on expired version of this technology
Early 20th-century naval battleships
Transatlantic passenger liners
Modern marine gyroscopic navigation systems
How to cite this patent in your documentation
Sperry Gyroscope Co Inc. US Patent 1242065. Ship's gyroscopic-compass set.. Granted 1917, expired 1934. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.