Patent US4378701A successfully refreshed from Google Patents.
US4378701A
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US
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Apparatus and method for indicating stress in an object
Assignee: SIRA INSTITUTE Ltd
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Filing: 1979-05-25
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Granted: 1983-04-05
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Expires: 1999-05-25
Abstract
Abstract Apparatus and method for indicating stress in an object comprising viewing the temperature variation of part of the surface of the object as it is stressed. An infra-red detector detects small changes of temperature and the stress may be applied by natural loading or by cyclic stressing imposed by a vibrator.
Inventors
- 👤 David S. Mountain
- 👤 Anthony J. Allnutt
- 👤 Lionel R. Baker
- 👤 Laurence J. Cox
- 👤 Alan J. Picot
- 👤 Peter F. Wardropper
- 👤 Julian M. Webber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:57
CPC Classifications
G; G01; G01L; G01L1/00; G01L1/24; G01L1/248; G01N; G01N25/00; G01N25/72
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
80 words
A method for indicating and distinguishing tension and compression in a predetermined part of a complex shaped object comprising determining a continuously changing load on the object and measuring and distinguishing increases and decreases in temperature of the predetermined part of the object with change of load, said measuring of the temperature being performed by determining the thermal radiation of the predetermined part and correlating these changes of temperature with respect to the instantaneous value of the continuously changing load.
Claim 2
Independent Claim
80 words
A method for indicating and distinguishing tension and compression in a predetermined part of a complex shaped object comprising determining a continuously changing load on the object and measuring and distinguishing increases and decreases in temperature of the predetermined part of the object with change of load, said measuring of the temperature being performed by determining the thermal radiation of the predetermined part and correlating these changes of temperature with respect to the instantaneous value of the continuously changing load.
Claim 3
Dependent Claim
14 words
A method as claimed in claim 1 in which the load change is unidirectional.
Claim 4
Dependent Claim
14 words
A method as claimed in claim 1 in which the load change is random.
Claim 5
Dependent Claim
17 words
A method as claimed in claim 1 in which the load change is applied and is cyclic.
Claim 6
Dependent Claim
18 words
A method as claimed in claim 4 in which the load change changes cyclically at a predetermined frequency.
Claim 7
Dependent Claim
52 words
A method as claimed in claim 4 or 5 in which the relative phase of changes of temperature of the predetermined part of the object and the change of applied load is determined whereby to determine whether a particular applied load produces tension or compression in that predetermined part of the object.
Claim 8
Dependent Claim
33 words
A method as claimed in claim 6 in which the load change is applied between two mechanically constrained spaced points of the object and said predetermined part is between said two spaced points.
Claim 9
Dependent Claim
21 words
A method as claimed in claim 1 in which the temperature of said predetermined part is measured by an infra-red detector.
Claim 10
Dependent Claim
26 words
A method as claimed in claim 1 in which the predetermined part of the object whose temperature is measured is scanned by thermal radiation determining means.
Claim 11
Dependent Claim
21 words
A method as claimed in claim 1 in which before testing the object, a coating is applied having uniform thermal emissivity.
Claim 12
Dependent Claim
56 words
The method as claimed in claim 1 further including a method of determining discontinuities in the object in which a cyclic load is applied by comparing in an analyser a waveform received from a load applying means with a temperature variation waveform received from a temperature detecting means to determine any assymmetry in the latter waveform.
Claim 13
Dependent Claim
94 words
Apparatus for indicating and distinguishing tension and compression in a predetermined part of a complex shaped object comprising means for determining a continuously changing load on the object, thermal radiation determining means for measuring and distinguishing increases and decreases in temperature of the predetermined part of the object with change of the load applied to the object and signal processing means for receiving a signal from said measuring and distinguishing means and from said load determining means to correlate these signals to produce an output indicating and distinguishing tension and compression at said part.
Claim 14
Dependent Claim
94 words
Apparatus for indicating and distinguishing tension and compression in a predetermined part of a complex shaped object comprising means for determining a continuously changing load on the object, thermal radiation determining means for measuring and distinguishing increases and decreases in temperature of the predetermined part of the object with change of the load applied to the object and signal processing means for receiving a signal from said measuring and distinguishing means and from said load determining means to correlate these signals to produce an output indicating and distinguishing tension and compression at said part.
Claim 15
Dependent Claim
36 words
Apparatus as claimed in claim 12 in which the apparatus further includes means for recording the signal produced by the temperature measuring means, whereby the recorded signal may thereafter be passed to the signal processing apparatus.
Claim 16
Dependent Claim
27 words
Apparatus as claimed in claim 13 in which a means for applying load to the object is arranged to vary the load cyclically at a predetermined frequency.
Claim 17
Dependent Claim
19 words
Apparatus as claimed in claim 14 in which the means for producing the load comprises a vibratory hydraulic ram.
Claim 18
Dependent Claim
31 words
Apparatus as claimed in claim 15 in which the hydraulic means for driving the hydraulic ram is adapted to provide a control signal in synchronism with the vibration of the ram.
Claim 19
Dependent Claim
27 words
Apparatus as claimed in claim 12 in which a means for applying load to the object is arranged to vary the load cyclically at a predetermined frequency.
Claim 20
Dependent Claim
20 words
Apparatus as claimed in claim 12 in which the means for measuring the variation in temperature comprises an infrared detector.
Claim 21
Dependent Claim
29 words
Apparatus as claimed in claim 18 in which there is provided an infrared lens for focusing radiation from the part of the object on to the infra red detector.
Claim 22
Dependent Claim
40 words
Apparatus as claimed in claim 12 further including means for applying a varying load to the object and display means for presenting a pictorial display of the variation of temperature with change of load across the surface of the object.
Claim 23
Dependent Claim
19 words
Apparatus as claimed in claim 20 in which the display means is adapted to provide a two dimensional display.
Claim 24
Dependent Claim
23 words
Apparatus as claimed in claim 20 in which the display means is adapted to display temperature variation by means of variation of brightness.
Claim 25
Dependent Claim
23 words
Apparatus as claimed in claim 20 in which the display means is adapted to display temperature variation by means of variation of colour.
Claim 26
Dependent Claim
22 words
Apparatus as claimed in claim 20 in which the display means is adapted to display temperature variation by means of contour lines.
Claim 27
Dependent Claim
23 words
Apparatus as claimed in claim 20 in which the display means is adapted to display temperature variation by means of variation of numerals.
Claim 28
Dependent Claim
25 words
Apparatus as claimed in claim 20 in which there is provided scanning means for scanning the part of the object whose temperature variation is measured.
Claim 29
Dependent Claim
17 words
Apparatus as claimed in claim 26 in which the apparatus is adapted to provide a linear scan.
Claim 30
Dependent Claim
17 words
Apparatus as claimed in claim 26 in which the apparatus is adapted to provide a raster scan.
Claim 31
Dependent Claim
17 words
Apparatus as claimed in claim 26 in which the apparatus is adapted to provide a spiral scan.
Claim 32
Dependent Claim
15 words
Apparatus as claimed in claim 26 in which the scanning means comprises two rotatable mirrors.
Claim 33
Dependent Claim
16 words
Apparatus as claimed in claim 30 in which stepping motors are provided to rotate the mirrors.
Claim 34
Dependent Claim
58 words
Apparatus as claimed in claim 31 in which the signal processing means includes a bidirectional peak detector, the outputs from the stepping motors being utilized to produce a movement of the display signal in a horizontal and vertical direction and the output signal from the bidirectional peak detector being utilised to vary some characteristic of the display signal.
Claim 35
Dependent Claim
14 words
Apparatus as claimed in claim 32 in which the display means comprises an oscilloscope.
Claim 36
Dependent Claim
20 words
Apparatus as claimed in claim 33 in which a camera is focused on the oscilloscope to record the display produced.
Claim 37
Dependent Claim
22 words
Apparatus as claimed in claim 12 including means for applying a variable load between two mechanically constrained spaced points on the object.
Claim 38
Dependent Claim
60 words
Apparatus as claimed in claim 35 in which there is provided means for mounting the object, and the means for applying the load is spaced from the means for mounting the object, said apparatus being aligned to indicate the load in the object at a point between the means for mounting the object and the means for applying the load.
Claim 39
Dependent Claim
59 words
Apparatus as claimed in claim 12 further including means for applying a cyclic load to the object and means connected to receive signals from the load applying means and from the measuring means for determining any difference between the waveform of the cyclic load and the wave form of the temperature variation whereby to determine discontinuities in the object.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-04-04 | 1986-10-04 | 1987-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-04 | 1990-10-04 | 1991-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-04 | 1994-10-04 | 1995-04-05 | $7700.00 | Window Closed / Lapsed |