| 1931 ORTNER Car Buffer Mechanism Patent Print |
| 1931 KAUTZKY Single Trigger Mechanism Patent |
| 1931 MARCEL Timepiece Winding Mechanism Patent |
| 1931 IVER SYVERSTAD Power Mechanism Patent Print |
| 1931 OHLENDORF Bumper Mechanism Patent Print Art |
| 1931 HARLEIGH Clock Operating Mechanism Patent |
| 1931 ERNEST CANTELO WHITE Clock Mechanism Patent |
| 1931 FRED ASHWORTH Take Up Mechanism Patent |
| 1931 FRED ASHWORTH Feeding Mechanism Patent |
| 1931 RUDOLF Alarm Clock Mechanism Patent Print |
| 1931 ROSS FREDERICK Sewing Mechanism Patent |
| 1931 HORN Clutch Control Mechanism Patent Print |
| 1931 BUCKENDALE Driving Mechanism Patent Print |
| 1931 WARREN Spring Winding Mechanism Patent |
| 1931 DALTON JOHN Cam Mechanism Patent Print Art |
| 1931 JOYCE Fluid Brake Mechanism Patent Print |
| 1931 MARTEL Automobile Locking Mechanism Patent |
| 1931 RICHARD H WRIGHT Cam Mechanism Patent Print |
| 1931 BOSSLER Switch Operating Mechanism Patent |
| 1931 MAX Electric Clock Driving Mechanism Patent |
| 1931 SPAINE Cam And Follower Mechanism Patent |
| 1931 FICHTEN FRANK Clock Mechanism Patent Print |
| 1931 JOE Propelling Mechanism Patent Print Art |
| 1931 PLUMLEY RAYMOND Clutch Mechanism Patent |
| 1931 FORREST Cable Cutting Mechanism Patent |
| 1931 DENT FERRELL Blasting Mechanism Patent |
| 1931 CONLEY Railway Switch Mechanism Patent |
| 1931 ALLEN Thread Feeding Mechanism Patent Print |
| 1931 BARTUSCH Time Release Mechanism Patent |
| 1931 EDUARD Pointing Mechanism For Guns Patent |
| 1931 LINO Clock Striking Mechanism Patent Print |
| 1931 PEDERSEN Rear Sight Mechanism Patent Print |
| 1931 WHITTINGTON Railway Switch Mechanism Patent |
| 1931 LOUIS Trigger Mechanism For Firearms Patent |
| 1931 ROBERDS Cycle Driving Mechanism Patent |
| 1931 FELDKAMP FREDERICK Clock Mechanism Patent |
| 1931 CLAUDE Starter Mechanism Lock Patent Print |
| 1931 PETERSON Vehicle Locking Mechanism Patent |
| 1931 POOLE Electric Clock Mechanism Patent Print |
| 1931 BENNETT Acoustic Signal Mechanism Patent |
| 1931 HALL Propulsion Mechanism Patent Print Art |
| 1931 HALL EDWARD Propulsion Mechanism Patent |
| 1931 JOHN Vehicle Propelling Mechanism Patent |
| 1931 LONGSTREET Boat Propulsion Mechanism Patent |
| 1931 JOE PIANO Propelling Mechanism Patent Print |
| 1931 CAMPBELL Hoist Or Lifting Mechanism Patent |
| 1931 ARMSTRONG Winding Mechanism Patent Print |
| 1931 JOHN STECHAUNER Propelling Mechanism Patent |
| 1931 BLOSSOM Automobile Locking Mechanism Patent |
| 1931 FRED ASHWORTH Shuttle Mechanism Patent |
| 1931 CRAIG Mechanism Lock For Motor Cars Patent |
| 1931 BULL Shock Absorbing Mechanism Patent Print |
| 1931 MCCANN GEORGE Firing Mechanism Patent Print |