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Patent US4957374A successfully refreshed from Google Patents.
US4957374A
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Tunnel furnace height detector
Assignee: NGK Insulators Ltd
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Filing: 1989-03-24
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Granted: 1990-09-18
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Expires: 2009-03-24
Abstract
Abstract A tunnel furnace height detector used for detecting ceiling heights of a tunnel furnace. The detector includes a plurality of detecting units arranged on a trolley traveling in the tunnel furnace in a manner such that their heights are progressively lowered by predetermined distances. Each of the detecting units includes a support base, and a solid piece pivotally connected to the support base automatically returnable from a pivotally moved position forced by an external force to an original position. The solid piece has one end in contact with a lowered ceiling and the other end closing and opening a measuring circuit system forming a closed circuit.
Inventors
- 👤 Keiji Yasuda
- 👤 Tetsuo Kamijyo
- 👤 Kazuhiro Miyahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:14
CPC Classifications
F; F27; F27D; F27D21/00; F27B; F27B9/00; F27B9/30; F27B9/40; G; G01; G01B; G01B5/00; G01B5/02; G01B5/04; F27D3/00; F27D2003/0001; F27D2003/0004; F27D2201/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
137 words
A tunnel furnace height detector for detecting a variable ceiling height of a tunnel furnace, comprising a plurality of detecting units arranged on a trolley traveling in said tunnel furnace, said plurality of detecting units each having a height which is progressively increases by a predetermined distance, each of said detecting units comprising: a support base; and a solid piece pivotally connected to said support base, said solid piece having one end to contact said ceiling and another end to open or close an electrical measuring circuit; wherein said solid piece is pivoted when said one end contacts said ceiling such that said another end opens said electrical measuring circuit, and said solid piece automatically returns to a position where said another end closes said electrical measuring circuit when said one end is spaced from said ceiling.
Claim 2
Dependent Claim
137 words
A tunnel furnace height detector for detecting a variable ceiling height of a tunnel furnace, comprising a plurality of detecting units arranged on a trolley traveling in said tunnel furnace, said plurality of detecting units each having a height which is progressively increases by a predetermined distance, each of said detecting units comprising: a support base; and a solid piece pivotally connected to said support base, said solid piece having one end to contact said ceiling and another end to open or close an electrical measuring circuit; wherein said solid piece is pivoted when said one end contacts said ceiling such that said another end opens said electrical measuring circuit, and said solid piece automatically returns to a position where said another end closes said electrical measuring circuit when said one end is spaced from said ceiling.
Claim 3
Dependent Claim
37 words
The tunnel furnace height detector of claim 1, wherein said solid piece is pivotally connected to said support base at a position of said solid piece which is above a center of gravity of said solid piece.
Claim 4
Dependent Claim
43 words
The tunnel furnace height detector of claim 1, further comprising a contacting plate having a first end to contact said another end of said solid piece, said contacting plate having a center of gravity located on a side of said first end thereof.
Claim 5
Dependent Claim
51 words
The tunnel furnace height detector of claim 3, wherein said solid piece, said contacting plate and/or a pivotal shaft of said solid piece which connects said solid piece to said support base comprises a material mixed with at least one material selected from the group consisting of mullite, alumina and zirconia.
Claim 6
Dependent Claim
32 words
The tunnel furnace height detector of claim 1, wherein said support bases comprises a material mixed with at least one material selected from the group consisting of mullite, alumina, zirconia and cordierite.
Claim 7
Dependent Claim
36 words
The tunnel furnace height detector of claim 1, wherein said electrical measuring circuit comprises a thermocouple which measures temperatures in the tunnel furnace when said another end of said solid piece closes said electrical measuring circuit.
Claim 8
Dependent Claim
56 words
The tunnel furnace height detector of claim 6, further comprising a contacting plate having a first end to contact said another end of said solid piece, wherein one wire of said thermocouple is wound around a portion of said contacting plate and another wire of said thermocouple is wound around a portion of said support base.
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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) | 1993-09-17 | 1994-03-19 | 1994-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-17 | 1998-03-19 | 1998-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-17 | 2002-03-19 | 2002-09-18 | $7700.00 | Window Closed / Lapsed |