Patent US4618825A successfully refreshed from Google Patents.
US4618825A
Expired / Lapsed
US
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Electro-magnetic thickness measuring probe
Assignee: Individual
•
Filing: 1984-10-11
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Granted: 1986-10-21
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Expires: 2004-10-11
Abstract
Abstract An electro-magnetic thickness measuring probe has a pot core which has a central bore, a pot chamber coaxial to the central bore accommodating a winding, and a pot rim. A pole-piece has one end fixed into the central bore and a free front-face with a coaxial recess machined therein such that an outer shell remains around the recess. A hard-metal pin is seated in the recess and has a front-face forming a crowned contact surface which stands a little proud of the pot rim. A coaxial annular disk made of highly permeable magnetic material has an outer edge in contact with the pot rim, a non-magnetic slot, and an intrados-radius surface having a diameter greater than the diameter of the pole-piece but significantly smaller than the diameter of the pot chamber. The intrados-radius surface lies close to the front-face of the pole-piece, whereby the magnetic resistance between the intrados-radius surface and the outer shell is significantly greater than the magnetic resistance between the intrados-radius surface and the free front-face when the measuring probe is set down on a surface.
Inventors
- 👤 Helmut Fischer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:36
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/10; G01B7/105
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
211 words
An electro-magnetic thickness measuring probe having: a pot core of high permeable magnetic material which has a central bore, a pot chamber coaxial to the central bore accommodating a winding, and a pot rim, a pole-piece of high permeable magnetic material having one end fixed into the central bore and a free front-face with a coaxial recess machined therein such that an outer shell remains around the recess, and a hard-metal pin seated in the recess having a front-face forming a crowned contact surface which stands a little proud of the pot rim, and the improvement comprising: said pin being of low permeable magnetic material relative to the pole-piece a coaxial annular disk made of highly permeable magnetic material, slot extending from the intrados-radius surface to the outer edge, having an outer edge in contact with the pot rim, and an intrados-radius surface having a diameter greater than the diameter of the pole-piece but significantly smaller than the diameter of the pot chamber, said intrados-radius surface lying close to the front-face of the pole-piece, whereby the magnetic resistance between the intrados-radius surface and the outer shell is significantly greater than the magnetic resistance between the intrados-radius surface and the free front-face when the measuring probe is set down on a surface.
Claim 2
Dependent Claim
211 words
An electro-magnetic thickness measuring probe having: a pot core of high permeable magnetic material which has a central bore, a pot chamber coaxial to the central bore accommodating a winding, and a pot rim, a pole-piece of high permeable magnetic material having one end fixed into the central bore and a free front-face with a coaxial recess machined therein such that an outer shell remains around the recess, and a hard-metal pin seated in the recess having a front-face forming a crowned contact surface which stands a little proud of the pot rim, and the improvement comprising: said pin being of low permeable magnetic material relative to the pole-piece a coaxial annular disk made of highly permeable magnetic material, slot extending from the intrados-radius surface to the outer edge, having an outer edge in contact with the pot rim, and an intrados-radius surface having a diameter greater than the diameter of the pole-piece but significantly smaller than the diameter of the pot chamber, said intrados-radius surface lying close to the front-face of the pole-piece, whereby the magnetic resistance between the intrados-radius surface and the outer shell is significantly greater than the magnetic resistance between the intrados-radius surface and the free front-face when the measuring probe is set down on a surface.
Claim 3
Dependent Claim
14 words
Probe as claimed in claim 1, wherein the annular disk has a radial slot.
Claim 4
Dependent Claim
14 words
Probe as claimed in claim 2, wherein the radial slot passes through the disk.
Claim 5
Dependent Claim
27 words
Probe as claimed in one of claims 2 or 3, wherein the pot core has a radial slot which adjoins the radial slot of the annular disk.
Claim 6
Dependent Claim
19 words
Probe as claimed in claim 4, wherein the radial slot of the pot core extends to its central bore.
Claim 7
Dependent Claim
29 words
Probe as claimed in claim 1, wherein the diameter of the intrados-radius surface is approximately 1.5 to 2 times the diameter of the pole-piece immediately opposite the intrados-radius surface.
Claim 8
Dependent Claim
18 words
Probe as claimed in claim 1, wherein the outer shell is constricted in the area of the pin.
Claim 9
Dependent Claim
12 words
Probe as claimed in claim 7, wherein the constriction is circular cylindrical.
Claim 10
Dependent Claim
11 words
Probe as claimed in claim 7, wherein the constriction is conical.
Claim 11
Dependent Claim
27 words
Probe as claimed in claim 1, wherein the annular disk lies lower in the area of its intrados-radius surface than in the area of the pot rim.
Claim 12
Dependent Claim
22 words
Probe as claimed in claim 10, wherein the annular disk is embossed outwards in the form of the frustum of a cone.
Claim 13
Dependent Claim
22 words
Probe as claimed in claim 10, wherein the annular disk has a stamp fin, the bottom surface of which is ground flat.
Claim 14
Dependent Claim
21 words
Probe as claimed in claim 1, wherein the pin has a magnetic permeability in the range of 40-80 H o .
Claim 15
Dependent Claim
19 words
Probe as claimed in claim 13, wherein the magnetic permeability is in the range of 60 H o .
Claim 16
Dependent Claim
23 words
Probe as claimed in claim 13, wherein the pin is made of an alloy of the type 10.5% Co; 6.5% Va; 7% Mo.
Claim 17
Dependent Claim
30 words
Probe as claimed in claim 1, wherein the outer front-face of the hard-metal pin stands proud of the annular disk by about 5-50% of the diameter of the intrados-radius surface.
Claim 18
Dependent Claim
12 words
Probe as claimed in claim 16, wherein the pin stands proud 30%.
Claim 19
Dependent Claim
22 words
Probe as claimed in claim 1, comprising a fine adjustment device positioned at the pot core for adjusting the pole-piece during assembly.
Claim 20
Dependent Claim
52 words
Probe as claimed in claim 18, comprising a grub screw with a conical face screwed into the pot core, a back face on the pole-piece having a bevel in contact with the conical face of the grub screw, and a second grub screw having a crowned front-face that presses on the pole-piece.
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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) | 1989-10-20 | 1990-04-21 | 1990-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-20 | 1994-04-21 | 1994-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-20 | 1998-04-21 | 1998-10-21 | $7700.00 | Window Closed / Lapsed |