Perforated shear-plate for dry shavers
Abstract
Abstract This invention provides a perforated shear-plate for dry shavers, made of a soft, hardenable steel foil and comprising bridges which form a network between the holes and which have edges forming the rims of the holes, the edges being flanged and ground and the material in the region of the edges having a submicroscopic, extremely hard martensitic structure containing residual austenite. A process for manufacturing such shear-plates comprises stamping holes into a ribbon of soft, hardenable steel foil containing more than 0.5 percent carbon, flanging and then grinding the edges of the holes with simultaneous pulse heating of the material in the region of the flanged edges up to an austenite forming temperature, and abruptly cooling the ground flanged edges.
Inventors
- 👤 Leopold Nidetzky
Bibliographic Details
Claims Analysis
Total Claims: 2References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-21 | 1975-09-20 | 1976-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-21 | 1979-09-20 | 1980-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-21 | 1983-09-20 | 1984-03-21 | $7700.00 | Window Closed / Lapsed |