US3571579A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Assessing of surface profiles
Assignee: Rank Organization Ltd
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Filing: 1968-04-25
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Granted: 1971-03-23
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Expires: 1988-04-25
Abstract
Abstract This invention relates to an instrument for testing the surface profile of a workpiece for irregularities. A conventional stylus arrangement is used to derive signals representative of the irregularities of the workpiece profile relative to a convenient datum, and these signals are stored, for example on a film strip or a magnetic tape. Signals are then extracted from the store by operating on each successive value of the stored signal with a weighting function which is nominally symmetrical about an instantaneous midordinate. The resulting signal represents, for each successive part of the profile under test, the convolution of the respective part of the first signal with the said weighting function, and is arranged to represent a useful means line from which the surface irregularities indicated by the first signal may be assessed.
Inventors
- 👤 David John Whitehouse
- 👤 John Denzil Barr
- 👤 Richard Edmund Reason
- 👤 Thomas Charles Reeve
- 👤 Robert Claude Spragg
- 👤 Arthur Tisso Starr
- 👤 Peter Frederic Thoma Stillwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:51
CPC Classifications
G; G06; G06E; G06E3/00; G06E3/001; G01; G01B; G01B11/00; G01B11/30; G01B11/303; G06G; G06G7/00; G06G7/12; G06G7/19; G06G7/1914
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
128 words
An instrument for the assessment of profiles, especially the profiles of surface irregularities, the instrument comprising in combination: transducer means for producing from a profile a first signal proportional to the amplitude of the irregularities of said profile relative to a convenient datum, signal means defining a weighting function for any given instantaneous value of the first signal, which weighting storage means for storing said first signal, and means responsive to the storage means and to said weighting function signal means for deriving from said stored first signal a second signal representing at any instant the value of the convolution integral of a predetermined portion of the stored first signal with said weighting function, said second signal representing a mean profile from which the first signal is assessed.
Claim 2
Dependent Claim
128 words
An instrument for the assessment of profiles, especially the profiles of surface irregularities, the instrument comprising in combination: transducer means for producing from a profile a first signal proportional to the amplitude of the irregularities of said profile relative to a convenient datum, signal means defining a weighting function for any given instantaneous value of the first signal, which weighting storage means for storing said first signal, and means responsive to the storage means and to said weighting function signal means for deriving from said stored first signal a second signal representing at any instant the value of the convolution integral of a predetermined portion of the stored first signal with said weighting function, said second signal representing a mean profile from which the first signal is assessed.
Claim 3
Dependent Claim
31 words
An instrument as claimed in claim 1, wherein said second signal representing the mean profile is combined with a signal representing the actual profile, for direct numerical assessment of surface profile.
Claim 4
Dependent Claim
19 words
An instrument as claimed in claim 2, and including means for taking the algebraic sum of said two signals.
Claim 5
Dependent Claim
24 words
An instrument as claimed in claim 1, in which said storage means comprise means for recording the first signal on an information receptive material.
Claim 6
Dependent Claim
39 words
An instrument as claimed in claim 4, in which the means for deriving said second signal include a light source for scanning the material bearing the stored first signal, and photoelectric means responsive to light transmitted through said material.
Claim 7
Dependent Claim
42 words
An instrument as claimed in claim 5 wherein the signal means defining the weighting function comprises optical means for modulating the light received by said photoelectric means so as to give the appropriate weighting to the signal obtained from said photoelectric means.
Claim 8
Dependent Claim
46 words
An instrument as claimed in claim 6, in which said photoelectric means comprise a number of photoelectric cells, said optical means being arranged to divide the light to be received by said cells into a number of beams, each of which strikes an individual photoelectric cell.
Claim 9
Dependent Claim
37 words
An instrument as claimed in claim 7, in which said optical means comprise a number of cylindrical lenses each arranged to focus light emerging from a selected part of said photosensitive material onto an individual photoelectric cell.
Claim 10
Dependent Claim
29 words
An instrument as claimed in claim 7, in which certain of said photoelectric cells are arranged so that their output signals oppose the output signals of the remaining cells.
Claim 11
Dependent Claim
20 words
An instrument as claimed in claim 4, in which said storage means record the first signal on a photosensitive material.
Claim 12
Dependent Claim
15 words
An instrument as claimed in claim 10, in which said material is a film strip.
Claim 13
Dependent Claim
15 words
An instrument as claimed in claim 11, in which the film strip is Polaroid film.
Claim 14
Dependent Claim
24 words
An instrument as claimed in claim 11, and including means for processing said film strip when the said first signal has been recorded thereon.
Claim 15
Dependent Claim
51 words
An instrument as claimed in claim 4, wherein said material is a photosensitive material and the means for recording the first signal comprise a movable mirror, forming part of a galvanometer means operating in response to said first signal, the said mirror being arranged to reflect light onto said photosensitive material.
Claim 16
Dependent Claim
22 words
An instrument as claimed in claim 1, wherein said second signal is recorded for superposition on a graph representing the original profile.
Claim 17
Dependent Claim
34 words
An instrument as claimed in claim 1, wherein said storage means comprise an electrical delay network for storing said first signal representative of said irregularities, thereby deliberately delaying said signal for a predetermined time.
Claim 18
Dependent Claim
31 words
An instrument as claimed in claim 16, wherein said electrical delay network comprises resistances proportioned inversely with respect to the amplituDe of the desired weighting function for forming said convolution integral.
Claim 19
Dependent Claim
44 words
An instrument as claimed in claim 16, wherein said weighting function is symmetrical, and said delay network is in the form of a delay line which is open circuited, whereby the reflection from said open circuit provides the second half of the required response.
Claim 20
Dependent Claim
23 words
An instrument as claimed in claim 1, wherein said storage means comprise an insulated surface on which charge densities represent said first signal.
Claim 21
Dependent Claim
41 words
An instrument as claimed in claim 16, wherein said means for deriving a signal representing the desired convolution integral comprise an electrode forming the plate of an electrometer and shaped in the form of the weighting function of said convolution integral.
Claim 22
Dependent Claim
42 words
An instrument as claimed in claim 1, in which the storage means comprise a magnetic storage medium effective to store said first signal and at least one reading head in juxtaposition to the storage medium for reading the stored first signal therefrom.
Claim 23
Dependent Claim
45 words
An instrument as claimed in claim 21, wherein said at least one reading head includes conductors wound thereon and evenly spaced along the length of said reading head, whereby the signals received by the conductors are weighted relatively in accordance with a prescribed weighting function.
Claim 24
Dependent Claim
32 words
An instrument as claimed in claim 21, wherein said at least one reading head includes conductors wound thereon, the spacing of said conductors being proportioned in accordance with a prescribed weighting function.
Claim 25
Dependent Claim
60 words
An instrument as claimed in claim 21, including driving means for effecting relative movement between the magnetic medium and said at least one reading head at a predetermined rate, and wherein the effective sensitivity of said at least one reading head is varied along its length in the direction of said relative movement in accordance with a prescribed weighting function.
Claim 26
Dependent Claim
45 words
An instrument as claimed in claim 24, wherein the effective width of the said at least one reading head varies in a direction transverse to said direction of relative movement to vary the effective sensitivity of the reading head along said direction of relative movement.
Claim 27
Dependent Claim
38 words
An instrument as claimed in claim 21, including an oscillator producing a signal, a recording head effective to record said signal in the magnetic storage medium, and modulator means modulating said signal by means of the first signal.
Claim 28
Dependent Claim
38 words
An instrument as claimed in claim 21, wherein the magnetic storage medium comprises a drum having a magnetizable surface, driving means being provided for effecting relative rotation between the drum and the said at least one reading head.
Claim 29
Dependent Claim
35 words
An instrument as claimed in claim 21, wherein the magnetic storage medium comprises a magnetic tape, driving means being provided for effecting linear movement of the tape past the said at least one reading head.
Claim 30
Dependent Claim
115 words
An instrument for the assessment of profile, especially the profiles of surface irregularity, the instrument comprising in combination: transducer means for producing from a profile a first signal proportional to the amplitude of the irregularities of said profile relative to a convenient datum, signal filtering storage means for receiving the said first signal, said signal filtering storage means having a symmetrical impulse response, and means deriving from the filtering storage means a second signal representing at any instant the value of the convolution integral of a predetermined portion of the first signal with a weighting function conforming to said impulse response, said second signal representing a mean profile from which the first signal is assessed.
Claim 31
Dependent Claim
115 words
An instrument for the assessment of profile, especially the profiles of surface irregularity, the instrument comprising in combination: transducer means for producing from a profile a first signal proportional to the amplitude of the irregularities of said profile relative to a convenient datum, signal filtering storage means for receiving the said first signal, said signal filtering storage means having a symmetrical impulse response, and means deriving from the filtering storage means a second signal representing at any instant the value of the convolution integral of a predetermined portion of the first signal with a weighting function conforming to said impulse response, said second signal representing a mean profile from which the first signal is assessed.
Claim 32
Dependent Claim
19 words
An instrument as claimed in claim 29 in which the signal filtering storage means comprise an electric wave filter.
Claim 33
Dependent Claim
19 words
An instrument as claimed in claim 29 in which the signal filtering storage means comprise an electrical delay network.
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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) | 1974-03-22 | 1974-09-21 | 1975-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-22 | 1978-09-21 | 1979-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-22 | 1982-09-21 | 1983-03-23 | $7700.00 | Window Closed / Lapsed |