Patent US3975891A successfully refreshed from Google Patents.
US3975891A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mower blades
Assignee: Individual
•
Filing: 1974-02-22
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Granted: 1976-08-24
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Expires: 1994-02-22
Abstract
Abstract This invention relates to mower blades made of metal with an inner layer of extremely hard material and so devised that attrition in use serves to maintain a sharp cutting edge.
Inventors
- 👤 Roland Eric Gunther
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:34
CPC Classifications
A; A01; A01D; A01D34/00; A01D34/01; A01D34/412; A01D34/63; A01D34/73
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
82 words
In a mower blade for use on rotary type mowers a flat steel body, said body having cutting portions at its extremities, each said cutting portion having a knife edge, each of said cutting portions further comprising a composite of a layer of comminuted hard material between two layers of steel, and disposed in a plane parallel to the flat surfaces of said steel body so as to extend into and substantially embody the knife edge of each of said cutting portions.
Claim 2
Dependent Claim
82 words
In a mower blade for use on rotary type mowers a flat steel body, said body having cutting portions at its extremities, each said cutting portion having a knife edge, each of said cutting portions further comprising a composite of a layer of comminuted hard material between two layers of steel, and disposed in a plane parallel to the flat surfaces of said steel body so as to extend into and substantially embody the knife edge of each of said cutting portions.
Claim 3
Dependent Claim
15 words
The construction of claim 1 wherein the said hard comminuted material comprises crushed cutlery steel.
Claim 4
Dependent Claim
23 words
The construction of claim 1 wherein the said hard comminuted material comprises Tungsten Carbide Alloy having a Knoop hardness of 1400 to 1800.
Claim 5
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Zirconium Boride.
Claim 6
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Titanium Nitride.
Claim 7
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Tungsten Carbide.
Claim 8
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Tantalum Carbide.
Claim 9
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Zirconium Carbide.
Claim 10
Dependent Claim
12 words
The construction of claim 1 wherein said hard comminuted material comprises Alumina.
Claim 11
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Beryllium Carbide.
Claim 12
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Titanium Carbide.
Claim 13
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Silicon Carbide.
Claim 14
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Aluminum Boride.
Claim 15
Dependent Claim
13 words
The construction of claim 1 wherein said hard comminuted material comprises Boron Carbide.
Claim 16
Dependent Claim
12 words
The construction of claim 1 wherein said hard comminuted material comprises Diamond.
Claim 17
Dependent Claim
32 words
In a mower blade for use on rotary type mowers the construction of claim 1 wherein said flat steel body is further surface clad on both flat sides in said cutting portions.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |