Patent EP0518205A1 successfully refreshed from Google Patents.
US3609288A
Expired / Lapsed
US
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Electron beam seam-finding method and apparatus
Assignee: Sciaky Brothers Inc
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Filing: 1968-12-18
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Granted: 1971-09-28
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Expires: 1988-12-18
Abstract
Abstract The present invention is for a method for determining the point of impingement of an electron beam with reference to the position of the seam between the two parts which are to be welded as may be used in the electron beam welding process. The electron beam is oscillated along a line transverse to the seam or along any other convenient path which traverses the seam. Secondary electrons emitted from the surface of the workpieces being scanned by the oscillating beam are collected by an electrode mounted above the work surface. The changes in secondary electron current through the electrode are displayed on the face of the cathode-ray oscilloscope whose horizontal sweep is controlled by the oscillator which is generating the electron beam scanning waveform. The signal generator or oscillator which produces the scanning signal is periodically shorted for preset intervals so that the beam remains in its ''''at rest'''' position during these intervals and the horizontal sweep is also ''''at rest'''' during these intervals so that a bright marker spot is displayed on the cathode-ray oscilloscope which defines the rest position of the electron beam as it strikes the work. By moving the workpieces with respect to the electron beam in a direction transverse to the seam, this marker spot may be brought to superimpose over the pattern of secondary emission current at a point which indicates the minimum secondary emission. This is the point at which the beam is striking the workpieces at the seam.
Inventors
- 👤 Albert M Sciaky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:22
CPC Classifications
B; B23; B23Q; B23Q35/00; B23Q35/04; B23Q35/08; B23Q35/12; B23Q35/127; B23Q35/129; B23K; B23K15/00; B23K15/02; H; H01; H01J; H01J37/00; H01J37/30; H01J37/304
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
155 words
A method of determining the position of an electron beam with respect to the seam between two adjoining workpieces, comprising the steps of directing the said beam towards the seam between the adjoining workpieces, oscillating the beam across the seam and workpieces to cause the emanation of secondary electrons from the said workpieces, causing the beam to rest periodically at its undeflected position, collecting secondary electrons thus produced, passing the said secondary electrons through a resistor so as to generate a voltage proportional to the instantaneous value of the secondary electrons collected, applying the generated voltage to one set of deflection plates of a cathoderay oscilloscope having at least two sets of deflection plates at right angles to each other, applying a voltage which is in synchronism with said oscillating beam to the second set of deflection plates of the said cathode-ray oscilloscope and displaying the resulting waveform on the screen of the said oscilloscope.
Claim 2
Independent Claim
155 words
A method of determining the position of an electron beam with respect to the seam between two adjoining workpieces, comprising the steps of directing the said beam towards the seam between the adjoining workpieces, oscillating the beam across the seam and workpieces to cause the emanation of secondary electrons from the said workpieces, causing the beam to rest periodically at its undeflected position, collecting secondary electrons thus produced, passing the said secondary electrons through a resistor so as to generate a voltage proportional to the instantaneous value of the secondary electrons collected, applying the generated voltage to one set of deflection plates of a cathoderay oscilloscope having at least two sets of deflection plates at right angles to each other, applying a voltage which is in synchronism with said oscillating beam to the second set of deflection plates of the said cathode-ray oscilloscope and displaying the resulting waveform on the screen of the said oscilloscope.
Claim 3
Dependent Claim
22 words
A method in accordance with claim 1 in which the time during which the beam is caused to rest periodically is adjustable.
Claim 4
Dependent Claim
23 words
A method in accordance with claim 2 in which the motion of the oscillating beam is periodically arrested during each period of oscillation.
Claim 5
Dependent Claim
100 words
In an electron beam apparatus having means for generating, accelerating, and focusing a beam of electrons upon adjoining workpieces, additional means for periodically deflecting the said beam along a path which crosses the seam between the said workpieces, means for periodically maintaining the beam at its undeflected position for a preset length of time, means for collecting secondary electrons resulting from the impingement of said beam upon said workpieces, means for conducting the said electrons so as to cause a flow of current, and oscillograph means for displaying the analog of the instantaneous values of the said secondary electron current.
Claim 6
Dependent Claim
100 words
In an electron beam apparatus having means for generating, accelerating, and focusing a beam of electrons upon adjoining workpieces, additional means for periodically deflecting the said beam along a path which crosses the seam between the said workpieces, means for periodically maintaining the beam at its undeflected position for a preset length of time, means for collecting secondary electrons resulting from the impingement of said beam upon said workpieces, means for conducting the said electrons so as to cause a flow of current, and oscillograph means for displaying the analog of the instantaneous values of the said secondary electron current.
Claim 7
Dependent Claim
73 words
Apparatus as in claim 4 in which the oscillograph means is of the cathode-ray type having means for deflection of the cathode ray along each of two mutually perpendicular axes, means by which the deflection along one axis is kept in synchronism with the motion of the aforementioned beam of electrons and means by which the deflection along the second axis is made proportional to the instantaneous value of the secondary electron current.
Claim 8
Dependent Claim
58 words
Apparatus as in claim 4 in which the said means for periodically maintaining the generated voltage at zero comprises switch means connected across the output terminals of the aforementioned signal generator, means for closing the said switch means periodically for a preset interval of time and means for varying the frequency of closure of the said switch means.
Claim 9
Dependent Claim
50 words
Apparatus as in claim 4 in which the means for periodically deflecting the beam is a signal generator having output terminals across which a periodic wave voltage appears, means for amplifying the said voltage and means for periodically maintaining the generated voltage at zero for a preset length of time.
Claim 10
Dependent Claim
53 words
Apparatus as in claim 7 in which the means for periodically maintaining the voltage of the signal generator at zero comprises a pair of zener diodes, in inverse relationship, connected in series between one of the output terminals of the signal generator and one of the input terminals of the aforementioned amplifier means.
Claim 11
Independent Claim
174 words
An apparatus for determining the position of an electron beam with respect to the seam between two adjoining workpieces, said apparatus comprising means for generating, accelerating and focusing an electron beam upon workpieces, means for oscillating the beam upon the said workpieces along a predetermined path which crosses the said seam, means for causing the beam to rest periodically at its undeflected position, means for detecting secondary and reflected electrons which emanate from the point of impingement of the beam upon the work, including means for conducting the said secondary electrons so as to cause a current flow and means for generating a voltage proportional to the instantaneous value of the said secondary electron current, oscillograph means for displaying the instantaneous value of the said secondary electron current, and means for causing a bright marker spot to be displayed on the screen of the said oscillograph means, the said bright marker spot indicating the undeflected position of the beam with respect to the pattern of secondary emission displayed upon the screen of the oscillograph.
Claim 12
Independent Claim
174 words
An apparatus for determining the position of an electron beam with respect to the seam between two adjoining workpieces, said apparatus comprising means for generating, accelerating and focusing an electron beam upon workpieces, means for oscillating the beam upon the said workpieces along a predetermined path which crosses the said seam, means for causing the beam to rest periodically at its undeflected position, means for detecting secondary and reflected electrons which emanate from the point of impingement of the beam upon the work, including means for conducting the said secondary electrons so as to cause a current flow and means for generating a voltage proportional to the instantaneous value of the said secondary electron current, oscillograph means for displaying the instantaneous value of the said secondary electron current, and means for causing a bright marker spot to be displayed on the screen of the said oscillograph means, the said bright marker spot indicating the undeflected position of the beam with respect to the pattern of secondary emission displayed upon the screen of the oscillograph.
References Cited (Backward Citations)
US3426174A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |