US4700752A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Clock spring crack arrestor
Assignee: Individual
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Filing: 1985-12-23
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Granted: 1987-10-20
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Expires: 2005-12-23
Abstract
Abstract A crack arrestor for a pipe is in the form of a clock spring defined by a spiral band of high tensile strength material having an elasticity maintaining the band in contact with the pipe. A method for making the crack arrestor includes saturating high tensile strength filaments with a resin, winding the saturated filaments around a mandrel in a plurality of convolutions, and establishing an elastic set in the convolutions by curing the resin.
Inventors
- 👤 Norman C. Fawley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:50
CPC Classifications
B; B29; B29C; B29C53/00; B29C53/56; B29C53/58; B29C53/60; B29C53/62; B29C53/66; B29C63/00; B29C63/24; F; F16; F16L; F16L57/00; F16L57/02; F17; F17C; F17C1/00; F17C1/02; F17C1/04; F17C1/06
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
132 words
Apparatus for arresting a propagating ductile fracture in a pipe containing fluid under a presssure sufficient to subject the pipe to the possibility of a ductile fracture propagating at a high speed in a predetermined direction, comprising: means for stopping the propagating ductile fracture, said stopping means comprising a band of high tensile strength material defining a clock spring spiral terminating in an inner end and an outer end and having a plurality of elastic convolutions for encircling and engaging the pipe, each convolution having an inner surface and an outer surface in contract with corresponding surfaces of adjacent convolutions, said high tensile strength material comprising a plurality of continuous, high tensile strength filaments encapsulated in a resin matrix and extending through said clock spring spiral parallel to the direction of spirtal.
Claim 2
Dependent Claim
132 words
Apparatus for arresting a propagating ductile fracture in a pipe containing fluid under a presssure sufficient to subject the pipe to the possibility of a ductile fracture propagating at a high speed in a predetermined direction, comprising: means for stopping the propagating ductile fracture, said stopping means comprising a band of high tensile strength material defining a clock spring spiral terminating in an inner end and an outer end and having a plurality of elastic convolutions for encircling and engaging the pipe, each convolution having an inner surface and an outer surface in contract with corresponding surfaces of adjacent convolutions, said high tensile strength material comprising a plurality of continuous, high tensile strength filaments encapsulated in a resin matrix and extending through said clock spring spiral parallel to the direction of spirtal.
Claim 3
Dependent Claim
11 words
Apparatus according to claim 1 wherein said filaments are nonmetallic filaments.
Claim 4
Dependent Claim
12 words
Apparatus according to claim 2 wherein the nonmetallic filaments are glass fibers.
Claim 5
Dependent Claim
13 words
Apparatus according to claim 3 wherein the glass fibers are E-type glass fibers.
Claim 6
Dependent Claim
14 words
Apparatus according to claim 1 wherein said resin is tacky in its cured state.
Claim 7
Dependent Claim
47 words
Apparatus according to claim 1 wherein the elasticity of said convolutions biases said band into said clock spring spiral with a force greater than the weight of said band, whereby said band remains in its clock spring spiral when suspended by an outer end of said spiral.
Claim 8
Dependent Claim
14 words
Apparatus according to claim 1 wherein said filaments are held together by transverse filaments.
Claim 9
Dependent Claim
14 words
Apparatus according to claim 1 wherein the material of said band is electrically non-conductive.
Claim 10
Dependent Claim
114 words
The combination of a pipe susceptible to a propagating ductile fracture, and, in contact with the outer surface of said pipe, means for stopping the propagating ductile fracture, said stopping means comprising a band of high tensile strength material defining a clock spring spiral terminating in an inner end and an outer end and having a plurality of elastic convolutions encircling the pipe, the innermost convolution contacting the outer surface of the pipe and each other convolution contacting the adjacent inner convolution, said high tensile strength material comprising a plurality of continuous, high tensile strength filaments encapsulated in a resin matrix and extending through said clock spring spiral parallel to the direction of spiral.
Claim 11
Dependent Claim
114 words
The combination of a pipe susceptible to a propagating ductile fracture, and, in contact with the outer surface of said pipe, means for stopping the propagating ductile fracture, said stopping means comprising a band of high tensile strength material defining a clock spring spiral terminating in an inner end and an outer end and having a plurality of elastic convolutions encircling the pipe, the innermost convolution contacting the outer surface of the pipe and each other convolution contacting the adjacent inner convolution, said high tensile strength material comprising a plurality of continuous, high tensile strength filaments encapsulated in a resin matrix and extending through said clock spring spiral parallel to the direction of spiral.
Claim 12
Dependent Claim
70 words
The combination of claim 9 wherein said innermost elastic convolution of said clock spring spiral has, in its relaxed state, a radius of curvature smaller than the radius of curvature of the outer surface of the pipe, whereby the elasticity of the convolutions biases said innermost convolution into contact with the outer surface of the pipe and biases all of the other convolutions into contact with the adjacent inner convolutions.
Claim 13
Dependent Claim
41 words
The combination of claim 9, further comprising means for securing an inner end of said clock spring spiral to said pipe and an outer end of said clock spring spiral to its adjacent inner convolution, said securing means comprising an adhesive.
Claim 14
Dependent Claim
24 words
The combination of claim 11, further comprising means for fixing each said elastic convolution to adjacent elastic convolutions, said fixing means comprising an adhesive.
Claim 15
Dependent Claim
17 words
The combination of claim 12 wherein said adhesive is positioned at discrete locations between said elastic convolutions.
Claim 16
Dependent Claim
11 words
The combination of claim 9 wherein said filaments are nonmetallic filaments.
Claim 17
Dependent Claim
12 words
The combination of claim 14 wherein the nonmetallic filaments are glass fibers.
Claim 18
Dependent Claim
13 words
The combination of claim 15 wherein the glass fibers are E-type glass fibers.
Claim 19
Dependent Claim
14 words
The combination of claim 14 wherein said resin is tacky in its cured state.
Claim 20
Dependent Claim
32 words
The combination of claim 9 wherein the elasticity of said convolutions biases each said convolution into contact with the adjacent inner convolution and biases the innermost convolution into contact with the pipe.
Claim 21
Dependent Claim
14 words
The combination of claim 9 wherein said filaments are held together by transverse filaments.
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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) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |