US4618168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for the heat-sealing thermoplastic conduits with a bridging conductor
Assignee: Georg Fischer AG
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Filing: 1984-02-02
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Granted: 1986-10-21
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Expires: 2004-02-02
Abstract
Abstract A system for heat-sealing thermoplastic conduits involves a thermoplastic sleeve surrounding an electrically conductive heating wire arranged in a coil. A bridging conductor is located adjacent the heating element, but is separated from it by an insulation layer of predetermined thickness. When the sleeve is heated by supplying electric power to the heating element, the entire heating element generates heat during a first phase in which fusion pressure is applied between the sleeve and pipes being connected. The bridging connector is forced into contact with selected coils of the heating element to initiate a second phase. In the second phase, the heat produced in the area of the selected coils is automatically reduced by short circuiting such coils.
Inventors
- 👤 Alfred Thalmann
- 👤 Ernesto Lehmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:11
CPC Classifications
B; B29; B29C; B29C66/00; B29C66/50; B29C66/51; B29C66/52; B29C66/522; B29C66/5221; B29C65/00; B29C65/02; B29C65/34; B29C65/3404; B29C65/342; B29C65/3468; B29C65/66; B29C65/68; B29C66/01; B29C66/05; B29C66/10; B29C66/11; B29C66/112; B29C66/1122; B29C66/114; B29C66/1142; B29C66/5229; B29C66/90; B29C66/91; B29C66/914; B29C66/9161; B29C66/91641; B29C66/91643; B29C66/91645; B29C66/91651; B29C66/91655; F; F16; F16L; F16L47/00; F16L47/02; F16L47/03; G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/2401; B29C65/3472; B29C65/3476; B29C65/348; B29C66/94; B29C66/95; B29C66/959; B29C66/9592
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
77 words
An apparatus for heat-sealing thermoplastic conduits, comprising: a coupling element; an electrically conductive heating element within said coupling element; at least one bridging conductor adjacent said heating element, but spaced therefrom by insulation, said bridging conductor having a length substantially less than that of said heating element such that only a portion of said heating element is bridged by said bridging conductor upon displacement of said insulation; and means for compressing said coupling element about the conduits.
Claim 2
Independent Claim
77 words
An apparatus for heat-sealing thermoplastic conduits, comprising: a coupling element; an electrically conductive heating element within said coupling element; at least one bridging conductor adjacent said heating element, but spaced therefrom by insulation, said bridging conductor having a length substantially less than that of said heating element such that only a portion of said heating element is bridged by said bridging conductor upon displacement of said insulation; and means for compressing said coupling element about the conduits.
Claim 3
Dependent Claim
19 words
An apparatus according to claim 1 wherein said bridging conductor comprises a short circuit conductor of low ohmic resistance.
Claim 4
Dependent Claim
14 words
An apparatus according to claim 2 wherein said short circuit conductor is a wire.
Claim 5
Dependent Claim
13 words
An apparatus according to claim 3 wherein said wire is a copper wire.
Claim 6
Dependent Claim
22 words
An apparatus according to claim 2 wherein said bridging conductor is located adjacent means for receiving adjacent ends of conduits being connected.
Claim 7
Dependent Claim
22 words
An apparatus according to claim 1 wherein said bridging conductor is located adjacent means for receiving adjacent ends of conduits being connected.
Claim 8
Dependent Claim
37 words
An apparatus according to claim 1 wherein said insulation between said bridging conductor and said heating element has a predetermined thickness which will soften permitting said bridging conductor to contact said heating element in a predetermined time.
Claim 9
Dependent Claim
37 words
An apparatus according to claim 2 wherein said insulation between said bridging conductor and said heating element has a predetermined thickness which will soften permitting said bridging conductor to contact said heating element in a predetermined time.
Claim 10
Dependent Claim
15 words
An apparatus according to claim 1 wherein said bridging conductor comprises an additional heating element.
Claim 11
Independent Claim
132 words
An apparatus for heat-sealing thermoplastic conduits, comprising a sleeve of thermoplastic material having inherent shrinkage stresses causing said sleeve to shrink upon being heated, and having an inner surface and opposite longitudinal ends; an electrically conductive heating wire arranged in a coil in said sleeve adjacent said inner surface; and an electrically conductive bridging conductor in said sleeve spaced radially outwardly of said coil and separated from said coil by a relatively thin layer of thermoplastic material; whereby, upon supplying electrical energy to said coil during a first phase, said thin layer will soften and said sleeve will shrink such that said bridging conductor will electrically contact a portion of said coil initiating a second phase in which less heat is generated in said portion than in remaining portions of said coil.
Claim 12
Independent Claim
132 words
An apparatus for heat-sealing thermoplastic conduits, comprising a sleeve of thermoplastic material having inherent shrinkage stresses causing said sleeve to shrink upon being heated, and having an inner surface and opposite longitudinal ends; an electrically conductive heating wire arranged in a coil in said sleeve adjacent said inner surface; and an electrically conductive bridging conductor in said sleeve spaced radially outwardly of said coil and separated from said coil by a relatively thin layer of thermoplastic material; whereby, upon supplying electrical energy to said coil during a first phase, said thin layer will soften and said sleeve will shrink such that said bridging conductor will electrically contact a portion of said coil initiating a second phase in which less heat is generated in said portion than in remaining portions of said coil.
Claim 13
Dependent Claim
20 words
An apparatus according to claim 10 wherein said bridging conductor is centrally located between said longitudinal ends of said sleeve.
Claim 14
Dependent Claim
16 words
An apparatus according to claim 1 wherein said coupling element comprises a sleeve of thermoplastic material.
Claim 15
Dependent Claim
21 words
An apparatus according to claim 12 wherein said sleeve comprises inherent shrinkage stresses causing said sleeve to shrink upon being heated.
Claim 16
Dependent Claim
20 words
An apparatus according to claim 10 wherein said bridging conductor has an axial length less than that of said coil.
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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 |