| 1921 DUDLEY Railway Switch Operating Mechanism |
| 1921 WOOD Controller Operating Mechanism Patent |
| 1921 MCCONWAY TORLEY CO Coupling Operating Mechanism |
| 1921 PRESSED STEEL CAR CO Door Operating Mechanism |
| 1921 ELECTRIC FLASHER Controller Operating Mechanism |
| 1921 MARANVILLE Valve Operating Mechanism Patent |
| 1921 MILTON Switch Operating Mechanism Patent |
| 1921 WILLIAM Coupling Operating Mechanism Patent |
| 1921 GOODYEAR TIRE RUBBER Valve Operating Mechanism |
| 1921 BLEST Door Operating Mechanism Patent Print |
| 1921 CONVERSE Steam Whistle Operating Mechanism |
| 1921 PRESSED Discharge Door Operating Mechanism |
| 1921 ERNST Gate Operating Mechanism Patent Print |
| 1921 THOMAS Car Door Operating Mechanism Patent |
| 1921 ARGYLE Dump Car Door Operating Mechanism |
| 1921 SINGER CO Needle Bar Operating Mechanism |
| 1921 GLEN End Gate Operating Mechanism Patent |
| 1921 LEONARD Hydraulic Operating Mechanism Valves |
| 1921 ENTPR Dump Car Door Operating Mechanism |
| 1921 DE Needle Bar Operating Mechanism Patent |
| 1921 KAUP Discharge Door Operating Mechanism Art |
| 1921 JOSEPH Coupling Operating Mechanism Patent |