Patent US3622751A successfully refreshed from Google Patents.
US3622751A
Expired / Lapsed
US
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Method and apparatus for electrically perforating sheet or web material
Assignee: Consolidated Paper Bahamas Ltd
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Filing: 1969-06-12
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Granted: 1971-11-23
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Expires: 1989-06-12
Abstract
Abstract A method and apparatus for perforating a web or sheet of material by passing a plurality of sparks through the web, with the first spark forming the perforation and the remaining sparks enlarging the perforation, and controlling the number of sparks to control the size of the perforation.
Inventors
- 👤 Rene Larive
- 👤 Richard L C Knight
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:52
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/02; B23H9/00; B23H9/14; B26; B26F; B26F1/00; B26F1/26; B26F1/28; Y; Y10; Y10T; Y10T83/00; Y10T83/525; Y10T83/533
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
146 words
A method of perforating a web comprising the steps of: relatively moving the web in a path of travel between a gap defined by a plurality of pairs of electrodes; at least one electrode of each said pair being a point electrode; providing a high-frequency alternating voltage to each said plurality of pairs of electrodes; passing an electrical discharge between each pair of electrodes of said plurality of pairs of electrodes and thus through the web whereby the first discharge between each pair of electrodes forms a perforation in the web; passing at least one further electrical discharge across each pair of said plurality of pairs of electrodes in the area of said perforation thereby to enlarge said perforation immediately after said perforation is formed; and adjustably controlling the number of said further electrical discharges enlarging the perforation thereby to control the size of perforation formed.
Claim 2
Independent Claim
146 words
A method of perforating a web comprising the steps of: relatively moving the web in a path of travel between a gap defined by a plurality of pairs of electrodes; at least one electrode of each said pair being a point electrode; providing a high-frequency alternating voltage to each said plurality of pairs of electrodes; passing an electrical discharge between each pair of electrodes of said plurality of pairs of electrodes and thus through the web whereby the first discharge between each pair of electrodes forms a perforation in the web; passing at least one further electrical discharge across each pair of said plurality of pairs of electrodes in the area of said perforation thereby to enlarge said perforation immediately after said perforation is formed; and adjustably controlling the number of said further electrical discharges enlarging the perforation thereby to control the size of perforation formed.
Claim 3
Dependent Claim
30 words
A method as claimed in claim 1, including controlling the number of perforations produced in relation to the relative rate of travel of the web with respect to the electrodes.
Claim 4
Dependent Claim
49 words
A method as defined in claim 1, including the step of providing a source of alternating voltage, causing said pairs of electrodes to discharge on every half-cycle of said alternating voltage, and adjustably controlling the number of said half-cycles thereby to control the number of said further electrical discharges.
Claim 5
Dependent Claim
28 words
A method as claimed in claim 3, including providing a series of control pulses of predetermined width, each control pulse corresponding to a half-cycle of said alternating voltage.
Claim 6
Dependent Claim
20 words
A method as claimed in claim 4, wherein the frequency of the control pulses is a function of web speed.
Claim 7
Independent Claim
123 words
An apparatus for perforating a web comprising means for relatively moving the web in a path of travel between a gap defined by a plurality of pairs of electrodes, at least one electrode of each said pair of electrodes being a point electrode, a source of high-frequency electrical pulses electrically connected to said electrodes and having sufficient potential to cause electrical discharges to pass between each pair of electrodes and through the web whereby the first discharge between each pair of electrodes forms a perforation in the web and each succeeding discharge across each pair of electrodes enlarges the perforation formed, electronic control means for adjustably controlling the number of electrical discharges enlarging the perforation to control the size of the perforation formed.
Claim 8
Independent Claim
123 words
An apparatus for perforating a web comprising means for relatively moving the web in a path of travel between a gap defined by a plurality of pairs of electrodes, at least one electrode of each said pair of electrodes being a point electrode, a source of high-frequency electrical pulses electrically connected to said electrodes and having sufficient potential to cause electrical discharges to pass between each pair of electrodes and through the web whereby the first discharge between each pair of electrodes forms a perforation in the web and each succeeding discharge across each pair of electrodes enlarges the perforation formed, electronic control means for adjustably controlling the number of electrical discharges enlarging the perforation to control the size of the perforation formed.
Claim 9
Dependent Claim
15 words
An apparatus as claimed in claim 6, wherein said source is an alternating voltage source.
Claim 10
Dependent Claim
33 words
An apparatus as claimed in claim 7, wherein the adjustable control means includes electronic gate means controlling the passage of a predetermined number of half-cycles of alternating voltage from said alternating voltage source.
Claim 11
Dependent Claim
36 words
An apparatus as claimed in claim 8, wherein said electronic gate means controlling the passage of the half-cycles includes two oppositely conducting controlled rectifiers conducting respectively on the positive and negative peaks of each voltage cycle.
Claim 12
Dependent Claim
42 words
An apparatus as claimed in claim 9, wherein said electronic control means further includes means for generating a series of control pulses, said series of control pulses being applied to said control rectifiers to govern the conducting period for said control rectifiers.
Claim 13
Dependent Claim
22 words
An apparatus as claimed in claim 15, including means controlling the frequency of the control pulses as a function of web speed.
Claim 14
Dependent Claim
139 words
A circuit for use in a system to perforate a web comprising rate-of-movement-sensing means for generating a control pulse in relation to the rate of movement of said web; pulse-shaping means connected to said rate-of-movement-sensing means for generating a squared waveform control pulse of a predetermined width; coupling transformer means connected to said pulse-shaping means for generating a control current; current rectifier means having control gate means connected to said coupling transformer means; alternating current generating means connected to said current rectifier means; and current discharge means connected to said current-generating means and said current rectifier means whereby periodic generation of a shaped control pulse results in the generation of a controlled number of static discharges the first of said controlled number of static discharges perforating said web and the remaining number of said static discharges enlarging said perforation.
Claim 15
Dependent Claim
139 words
A circuit for use in a system to perforate a web comprising rate-of-movement-sensing means for generating a control pulse in relation to the rate of movement of said web; pulse-shaping means connected to said rate-of-movement-sensing means for generating a squared waveform control pulse of a predetermined width; coupling transformer means connected to said pulse-shaping means for generating a control current; current rectifier means having control gate means connected to said coupling transformer means; alternating current generating means connected to said current rectifier means; and current discharge means connected to said current-generating means and said current rectifier means whereby periodic generation of a shaped control pulse results in the generation of a controlled number of static discharges the first of said controlled number of static discharges perforating said web and the remaining number of said static discharges enlarging said perforation.
Claim 16
Dependent Claim
43 words
In a circuit as set forth in claim 12, in which said current rectifier means comprises a pair of controlled rectifiers in back-to-back configuration for alternately generating a static discharge during each half-cycle of alternating current when made conducting by the control pulse.
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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) | 1974-11-22 | 1975-05-24 | 1975-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-22 | 1979-05-24 | 1979-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-22 | 1983-05-24 | 1983-11-23 | $7700.00 | Window Closed / Lapsed |