US Patent 1,086,299, a packing-ring design assigned to the K D Motor Company, granted about eight months before Knight's death.
On February 3, 1914, Margaret Knight was granted US Patent 1,086,299 for a packing-ring design, again assigned to the K D Motor Company. Packing rings are critical mechanical seals used within engines to maintain pressure and prevent leakage — a small but essential component in internal combustion engine design.
This patent, granted roughly eight months before her death on October 12, 1914, stands as one of the final testaments to Knight's lifelong dedication to invention. At 75 years old, she was still actively working on precise, technical engineering problems within the automotive industry, a field that had not even existed for the majority of her lifetime.
The continuity of her assignment relationship with the K D Motor Company across multiple patents in 1913 and 1914 indicates a sustained professional engineering partnership in her final years, rather than a series of disconnected inventions. This patent, together with her other automotive work, forms part of the roughly 27 verified patents she held at the time of her death — spanning paper manufacturing, domestic goods, shoe machinery, and automotive engineering. A final patent, US 1,132,858, would be granted posthumously in March 1915, underscoring that her inventive work continued literally to the end of her life.