| 1920 LA MERE Railway Signal Patent Print Art |
| 1920 HANDLAN BUCK MFG COMPANY Signal Lamp Patent |
| 1920 WILLIAMS Audible Theft Alarm Signal Automobiles |
| 1920 UNION SWITCH SIGNAL CO Track Instrument Art |
| 1920 ANDRESS BERT Railway Signal Patent Print |
| 1920 POLLMILLER Semaphore Signal Patent Print |
| 1920 GENN Portable Signal Device WARNER Patent 22411 |
| 1920 MAGNETIC SIGNAL Double Coil Oscillating Motor |
| 1920 SUBMARINE SIGNAL CO Method Producing Fog Screens |
| 1920 GENN Portable Signal Device Patent Print |
| 1920 LAWRENCE CURRIE Track Signal Patent Print |
| 1920 HANDLAN Adjustable Signal Lamp Support Art |
| 1920 ERNEST RUBES Warning Signal Patent Print |
| 1920 ANTONE Railroad Crossing Signal Patent |
| 1920 OMRI TREANOR Signal Patent Print Art |
| 1920 BLAIN Bearing Wear Signal Device Patent |
| 1920 MASSEY Foundation Housing Railway Signal |
| 1920 MARSH SARGENT Detection Signal Patent Print |
| 1920 MARR JOHN Auto Theft Signal Patent Print |
| 1920 RODENBUR Signal Carrying Case Patent Print |
| 1920 KELLAM ERNEST Train Signal Patent Print Art |
| 1920 FESSENDEN Locating Enemy Gun SIGNAL Patent 22412 |
| 1920 SMITH WILLIAM Railway Signal Patent Print |
| 1920 STEWART WARNER SPEEDOMETER Portable Signal |
| 1920 HUBBARD Combined Signal Emergency Train Stopping |
| 1920 AUGUST MEYER Signal Lamp Patent Print Art |
| 1920 JOSEPH Bearing Wear Signal Art Print |
| 1920 KUHLMANN Automobilists Hand Signal Patent 49659 |
| 1920 MAGNETIC SIGNAL Electric Switch Art Print |
| 1920 UNION SWITCH SIGNAL CO Control Railway Switches |
| 1920 MICHELS Railway Cab Signal Patent Print Art |
| 1920 WANKLYN FREDERIC Track Signal Patent Print |
| 1920 ERNEST SANDERS Car Door Signal Patent Print |
| 1920 SUBMARINE SIGNAL CO Method Sound Insulation |
| 1920 BIXBY Crossing Signal Railway Tracks Art |
| 1920 LOUIS Automobile Theft Signal Patent Print |
| 1920 SAWYER Train Operated Crossing Signal Art |
| 1920 OSCAR Highway Crossing Signal Patent Print |
| 1920 MAGNETIC SIGNAL Motor Comprising A Single Coil |
| 1920 HANDLAN Railway Signal Lamp Patent Print |
| 1920 HOBSON Foundation Housing Railway Signal |
| 1920 HARRELL WILLIAM Railroad Signal Patent |
| 1920 ZEIS Inclosing Casing Vehicle Signal Patent 49626 |
| 1920 MCQUARRIE Automobile Alarm Signal Patent |
| 1920 JOHN EVANS Railway Signal Patent Print Art |