US3037381A - Bump detector - Google Patents

Bump detector Download PDF

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Publication number
US3037381A
US3037381A US812895A US81289559A US3037381A US 3037381 A US3037381 A US 3037381A US 812895 A US812895 A US 812895A US 81289559 A US81289559 A US 81289559A US 3037381 A US3037381 A US 3037381A
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United States
Prior art keywords
skid
capacitor
web
bump
resistor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US812895A
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English (en)
Inventor
Clyde P Grant
Forrester Gilbert
Robert L Smith
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Warren SD Co
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Warren SD Co
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Publication date
Application filed by Warren SD Co filed Critical Warren SD Co
Priority to US812895A priority Critical patent/US3037381A/en
Priority to CH434160A priority patent/CH384352A/de
Application granted granted Critical
Publication of US3037381A publication Critical patent/US3037381A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/34—Paper
    • G01N33/346—Paper sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H43/00—Use of control, checking, or safety devices, e.g. automatic devices comprising an element for sensing a variable
    • B65H43/04—Use of control, checking, or safety devices, e.g. automatic devices comprising an element for sensing a variable detecting, or responding to, presence of faulty articles

Definitions

  • the object of this invention is to provide a new type of bump detector which is free of the limitations attendant to bump detectors heretofore devised.
  • a more specific object of this invention is to provide means for detecting sharp changes in the caliper of a moving web and for generating an electrical signal each time an abrupt change is discovered.
  • Another specific object of this invention is to provide a bump detector capable of operating efliciently regardless of the physical and chemical characteristics of the web being inspected.
  • FIG. 1 is a perspective view showing a plurality of bump detector skids positioned in operating relation to a paper web;
  • FIG. 2 is an enlarged plan view of one of the skid memers
  • FIG. 3 is a sectional view in elevation of the assem bly of FIG. 1;
  • FIG. 4 is a sectional view taken along line 44 of FIG. 3;
  • FIGS. 5 and 6 are enlarged fragmentary side views of two modified forms of skid.
  • FIG. 7 is a schematic diagram of an electric system employed with the skids to generate an electrical signal when a bump is detected.
  • FIG. 1 there is shown a portion of a bump detector assembly for use in a machine for (1) inspecting a paper web for predetermined types of defects, (2) cutting said web into sheets, and (3) separating defective sheets from sheets that are free of defects.
  • a machine is disclosed in our copending application for Apparatus for Inspecting, Cutting, and Sorting Paper, Serial No. 776,342, filed November 25, 1958.
  • the bump detector assembly comprises a horizontal beam 2 mounted above and slightly upstream of a roll 4 which supports a moving paper web 6.
  • Roll 4 may be a driven roll, or, if the paper is driven by other rolls, it may be simply an idler roll.
  • Attached to the beam 2 by means of bolts 8 is a series of brackets 10 each having a pair of parallel-spaced horizontal arms 12 which project in a downstream direction away from beam 2. Brackets 10 extend in an even line along beam 2 and function to support a plurality of skids identified generally by numeral 14.
  • each skid 14 comprises a body portion made up of two relatively thick plates 16 and 18 held in superposed relation by screws 20 and a rectangular metallic plate 22. A substantial portion of plate 22 is sandwiched tightly between plates 16 and 18. The latter are provided with matching semicylindrical grooves which define a channel in which is held a tube 24 whose ends contain bearings 26 and 28. Rotatably journaled in these bearings and extending beyond the ends of tube 24 is a shaft 30. The ends of shaft 30 are supported by the two arms 12 of bracket 10. Arms 12 are provided with V-shaped notches 32 which function as seats for the ends of shaft 30.
  • Tube 24 is located so that the center of gravity of the skid is slightly forward of shaft 30'.
  • each plate 22 may be prefectly flat at its forward edge, it is preferred that each one be bent to form a lip 40 at that edge. Lip 40 makes the edge more rigid and reduces any tendency for the plate to flex cornerwise or about the line of symmetry of the skid.
  • the line of symmetry of the skid is indicated by the broken line C-C in FIG. 2. Accordingly, any force applied to a portion of plate 22 will cause it to bend or flex along a line running parallel to its forward edge. Since plate 22 is anchored only along one edge, it is similar to a cantilever beam; and, accordingly, any flexing which it experiences tends to occur along the line of the forward edges 42' of plates 16 and 18.
  • the bump will produce a sharp blow on one of the skids as it travels over roll 4. Because the center of gravity of the skid is downstream of shaft 30, the skid will have a moment of inertia that tends to prevent the skid from pivoting upward. Consequently, the metal plate 22 will yield first to absorb the elfect of the blow and to allow the bump to pass on downstream, and almost instantaneously thereafter, the skid will pivot upward in reaction to the energy absorbed by the plate. In yielding to the bump, the metal plate bends upward (i.e., flexing) relative to the body portion of the skid. This flexing action is sufiiciently small in magnitude and occurs so fast as not to be discernible to the naked eye. However, it is of suflicient magnitude to be detected.
  • the deflection of the metal plates in response to bumps or rapid changes in web caliper is detected by means of a crystaltype phonograph pickup head identified generally by numetal 46.
  • the head is provided with a pair of flanges 48 and 50 which are provided with holes to receive screws 52 which cooperate with nuts 54 to anchor the head to a bracket 5'6.
  • flanges 48 and 50 are sandwiched between resilient washers 58 made of rubber or other suitable material.
  • Bracket 56 is made of rigid metal and has upturned sides 60 and 62 which prevent it from flexing about its center.
  • the bracket is fastened by short screws 64 and 66 to the top half 16 of the body portion of the skid and is oriented so that the forward end of the pickup head overlies metal plate 22.
  • Pickup 46 is disposed slightly to one side of the center line C-C of the skid.
  • a wire rod element 68 Secured to the cartridge in the hole normally occupied by a phonograph needle is a wire rod element 68 comprising a first inclined portion 70 formed integral with a second horizontally extending portion 72.
  • the top end of portion 70 is secured within the pickup head by a set screw 74.
  • To the free end of portion 72 is secured a conventional hex nut 76.
  • a screw 78 Mounted in nut 76 is a screw 78, Screw 78 is turned down into snug, but not tight, contact with plate 22.
  • the pickup head has two output terminals 80 and 82 which are connected by means of a two-wire cable 86 to the output circuit illustrated in FIG. 7.
  • the two terminals of pickup head 46 are connected to a band pass filter. More particularly, they are connected in series with two capacitors 92 and 94, two resistors 96 and 98, a third capacitor 100, and a third resistor 182 which is part of a potentiometer 104. Terminal 82 is grounded. A resistor 106 is connected at one end to the juncture of capacitors 92 and 94 and at the other end to ground. Another resistor 108 is connected between capacitor 94 and resistor 96 and at the other end to ground. A capacitor 110 is connected on one side to the juncture of resistors 96 and 98 and at the other side to ground.
  • Still another capacitor 112 is connected on one side to ground and on the other side to the juncture of resistor 98 and capacitor 100.
  • Capacitors 92 and 94 and resistors 106 and 108 have values suitable to pass all signals above approximately 200 cycles. The remaining resistors and capacitors have values suitable to pass all signals below 2000 cycles. As a result, spurious 60-cycle and other lowfrequency signals resulting from machine vibration or motor hum and any stray high frequency signals are eliminated, and only signals between 200 and 2000' cycles are passed. It has been found that signals generated by bumps in a paper web are concentrated in that band and that elimination of all other signals provides a great increase in response.
  • Potentiometer 104 has a slider 116 which is coupled directly to the control grid 118 of the left-hand half of a twin triode 120. Both cathodes 122 are connected to ground. The rightand left-hand plates 124 and 126 are connected in parallel with a positive voltage supply 128 through load resistors 130 and 132 respectively. Plate 124 is connected to the right-hand grid 134 by a capacitor 136. A resistor 138 is connected on one side to ground and on the other side to the juncture of grid 134 and capacitor 136. Capacitor 136 and resistor 138 function as a differentiating circuit.
  • Plate 126 is connected by a capacitor 140 to the control grid 142 of the pentode sec tion of a combination pentode-triode tube 144.
  • a resistor 146 is connected between ground and the junctures of capacitor 140 and control grid 142. Capacitor 140 and resistor 146 function as a differentiating circuit.
  • the plate 148 of the pentode is connected by a load resistor 150 to voltage supply 128.
  • the screen gn'd 152 is connected by load resistor 154 to the same voltage supply.
  • the suppressor grid'156 and pentode cathode 158 are connected to ground through a resistor 160.
  • Suppressor grid 156 is connected also to voltage supply 128 through a resistor 162.
  • the control grid 164 of the triode section of tube 144 is connected by a capacitor 166to plate 148 of the pentode.
  • a capacitor 168 is connected between ground and the juncture of grid 164 and capacitor 166.
  • a resistor 170 is connected in parallel with capacitor 168.
  • the triode plate 172 is connected to a second positive voltage supply 174 through the coil 176 of a switching it relay 178.
  • the latter has two normally closed switch contacts 180 and 182 which are opened when coil 176 is energized.
  • Contact 180 i s connected to an oscillator 184, and terminal 182 is connected to a magnetic recorder 186.
  • This pentode section is always conducting but below the linear portion of its operating wave. Hence, it amplifies positive pulses to a greater extent than negative pulses. These positive and negative pulses are amplified and inverted and applied to the control grid 164.
  • the right-hand half of tube 144 is normally conducting but is driven to cutoff by the negative pulses applied to grid 164.
  • coil 176 is deenergized, and contacts 180 and 182 reclose to couple oscillator 184 to recorder 186.
  • the right-hand section of tube 144 remains cut off for a short while after the negative pulse applied to its grid 164 has passed. This is necessary in order to allow the coil 176 to be deenergized long enough for contacts 180 and 182 to close.
  • the right-hand half of tube 144 is kept off by the voltage appearing across capacitor 168.
  • the time duration of the cutoff period of the tube is determined by the charge across capacitor 168 and the RC time constant of capacitor 168 and resistor 170.
  • the negative voltage across capacitor 168 bleeds off through resistor 170, and the right-hand half of the tube begins to conduct again when the voltage across capacitor 168 returns above the cutoff voltage.
  • the signal generated by a bump is of relatively short duration and decays rapidly to zero.
  • the generated signal train is so short as to appear as a single negative pulse at grid 164. It is believed to be obvious that any positive pulses which appear at grid 164 are so small as not to interfere with operation of the circuit as just described.
  • FIG. 7 includes a recorder for preserving the short ouput of oscillator 184, such a recorder is not necessary and is illustrated simply to show how the present invention may be substituted for the bump detector system of the apparatus disclosed in our copcnding application Serial No. 776,342.
  • the output of the oscillator passed by relay 178 need not be applied to a recorder but may, for example, be applied to an alarm system.
  • the oscillator may be omitted and relay 178 may be employed to op erate some other device, as, for example, a warning light.
  • the pickup heads for several skids may be connected in parallel to a single electrical system like the one shown in FIG. 7, or each pickup head may have its own system. It is further contemplated that the phonograph pickup heads need not be of the crystal type but may be of the magnetic type as well.
  • the invention is not limited to the exact skid shown in FIGS. 1 and 2.
  • Shoe is attached by means of a plurality of screws 192.
  • the shoe may be attached by a suitable adhesive or may be shaped or molded so that it may be attached without screws, as by gripping the plate edge in a tight groove.
  • the edges of the shoe are beveled as shown at 194 so as to provide better contact with the paper Web.
  • the shoe may be made out of any suitable material, preferably a plastic. Teflon has been found to be especially suitable.
  • the metal plate 22 need not have the sharp right-angle lip 40. Instead, it the metal plate is suificiently rigid, the lip may be omitted entirely. Alternatively, the lip may be formed by a more gentle curve, like the lip 40a shown in FIG. 6.
  • Apparatus for detecting abrupt changes in caliper of a moving web of paper comprising a roll for supporting said web, a skid support disposed adjacent to said roll, a skid having a body portion pivotally secured to said support with a flexible extension urged into light contact with said moving web, a transducer mounted on said body portion, and a probe on said transducer coupled to said flexible extension and responsive to relative motion between said extension and said body portion for translating flexing of said skid caused by an abrupt change in caliper of said web into an electrical signal indicative of said abrupt change in caliper.
  • Apparatus for detecting sharp changes in caliper of a moving web of paper comprising a horizontal roll for supporting said moving web, a skid supporting member located above and extending parallel to said roll, a skid comprising a relatively thick fiat substantially inflexible body member pivotally secured to said skid supporting member and a relatively thin flexible but torsion-resistant member for engaging said moving web along a transverse line, an elongated pickup probe in contact with said torsion-resistant member and movable in response to flexing of said same member relative to said body member, a transducer element mounted on said body member and supporting said pickup probe for producing an electrical signal in response to movement of said probe, and means for amplifying said signal.
  • Apparatus as defined by claim 2 further including means connecting said transducer and said amplifying means for eliminating signals having (1) a frequency below 200 cycles and (2) signals having a frequency above 2000 cycles.
  • Apparatus for detecting sharp changes in caliper of a moving web as it moves over a roll comprising a fixed member located above and extending transversely of the moving web, a skid pivotally attached to said fixed member, said skid comprising first and second fiat relatively thick rigid members and a third fiat flexible relatively thin member having a first portion thereof sandwiched tightly between said first and second members, said third member having a second portion in engagement with said moving web, a phonograph pickup head attached to one of said first and second members, said pickup head having a pickup element in engagement with the said second portion of said third member, and signal generating means connected to said pickup head for producing an output signal each time said pickup element is moved by flexing of said third member.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Controlling Sheets Or Webs (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
US812895A 1959-05-13 1959-05-13 Bump detector Expired - Lifetime US3037381A (en)

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US812895A US3037381A (en) 1959-05-13 1959-05-13 Bump detector
CH434160A CH384352A (de) 1959-05-13 1960-04-19 Verdickungsfühler für einen Querschneider

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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3357241A (en) * 1964-01-24 1967-12-12 Licentia Gmbh Fault sensing device for continuously moving web
US3363458A (en) * 1966-02-11 1968-01-16 Cutler Hammer Inc Apparatus for detecting surface imperfections on moving webs
US3367180A (en) * 1965-03-25 1968-02-06 Warren S D Co Self-aligning sensing skid
US3385106A (en) * 1966-06-30 1968-05-28 Western Publishing Company Inc Method and means for detecting sag in a sheet
US3403447A (en) * 1965-03-04 1968-10-01 Scott Paper Co Sensing skid shoe for caliper detectors
US3763373A (en) * 1972-03-15 1973-10-02 Du Pont Defect detector for a moving web
US4063051A (en) * 1976-05-04 1977-12-13 Standard Products Corporation Apparatus for detecting bumps in a web
US4224824A (en) * 1978-03-24 1980-09-30 Giampiero Giusti Detecting device for breaks or tears and for the end of the strip in a strip of any material during its advance
US4285745A (en) * 1979-08-01 1981-08-25 Ppg Industries, Inc. Method of determining optical quality of a laminated article
US4371482A (en) * 1979-08-01 1983-02-01 Ppg Industries, Inc. Method of determining optical quality of a shaped article
US4513613A (en) * 1983-06-07 1985-04-30 International Business Machines Corporation Particle detection system
US5014547A (en) * 1988-11-15 1991-05-14 Stresswave Technology Limited Apparatus for determining the surface roughness of a material
US5287742A (en) * 1991-01-10 1994-02-22 Nippon Petrochemicals Company Ltd. Device for detecting defects of web
WO1996027126A1 (de) * 1995-02-28 1996-09-06 Rhone-Poulenc Viscosuisse S.A. Verfahren und vorrichtung zur bestimmung von strukturfehlern an laufenden textilen flächengebilden
US6131452A (en) * 1995-02-28 2000-10-17 Rhodia Filtec Ag Process and device for detecting structural faults of moving flat textile materials
DE102018103393A1 (de) * 2018-02-15 2019-08-22 Gerd Rebmann Abtastvorrichtung

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2221516A (en) * 1937-04-01 1940-11-12 Gen Electric Continuous thickness gauge
US2392010A (en) * 1943-02-17 1946-01-01 Stevens Charles Flaw detector for sheet material
US2405133A (en) * 1942-10-07 1946-08-06 Brush Dev Co Method and means for measuring surface roughness
US2620655A (en) * 1949-10-08 1952-12-09 Physicists Res Company Instrument for recording or measuring the size and shape of surface irregularities
US2764018A (en) * 1954-06-10 1956-09-25 Goodyear Tire & Rubber Apparatus for analyzing the dynamic deflection of tires
US2942248A (en) * 1956-08-08 1960-06-21 Curtiss Wright Corp Apparatus and method for detecting abrupt changes in dielectric sheet material

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2221516A (en) * 1937-04-01 1940-11-12 Gen Electric Continuous thickness gauge
US2405133A (en) * 1942-10-07 1946-08-06 Brush Dev Co Method and means for measuring surface roughness
US2392010A (en) * 1943-02-17 1946-01-01 Stevens Charles Flaw detector for sheet material
US2620655A (en) * 1949-10-08 1952-12-09 Physicists Res Company Instrument for recording or measuring the size and shape of surface irregularities
US2764018A (en) * 1954-06-10 1956-09-25 Goodyear Tire & Rubber Apparatus for analyzing the dynamic deflection of tires
US2942248A (en) * 1956-08-08 1960-06-21 Curtiss Wright Corp Apparatus and method for detecting abrupt changes in dielectric sheet material

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3357241A (en) * 1964-01-24 1967-12-12 Licentia Gmbh Fault sensing device for continuously moving web
US3403447A (en) * 1965-03-04 1968-10-01 Scott Paper Co Sensing skid shoe for caliper detectors
US3367180A (en) * 1965-03-25 1968-02-06 Warren S D Co Self-aligning sensing skid
US3363458A (en) * 1966-02-11 1968-01-16 Cutler Hammer Inc Apparatus for detecting surface imperfections on moving webs
US3385106A (en) * 1966-06-30 1968-05-28 Western Publishing Company Inc Method and means for detecting sag in a sheet
US3763373A (en) * 1972-03-15 1973-10-02 Du Pont Defect detector for a moving web
US4063051A (en) * 1976-05-04 1977-12-13 Standard Products Corporation Apparatus for detecting bumps in a web
US4224824A (en) * 1978-03-24 1980-09-30 Giampiero Giusti Detecting device for breaks or tears and for the end of the strip in a strip of any material during its advance
US4285745A (en) * 1979-08-01 1981-08-25 Ppg Industries, Inc. Method of determining optical quality of a laminated article
US4371482A (en) * 1979-08-01 1983-02-01 Ppg Industries, Inc. Method of determining optical quality of a shaped article
US4513613A (en) * 1983-06-07 1985-04-30 International Business Machines Corporation Particle detection system
US5014547A (en) * 1988-11-15 1991-05-14 Stresswave Technology Limited Apparatus for determining the surface roughness of a material
US5287742A (en) * 1991-01-10 1994-02-22 Nippon Petrochemicals Company Ltd. Device for detecting defects of web
WO1996027126A1 (de) * 1995-02-28 1996-09-06 Rhone-Poulenc Viscosuisse S.A. Verfahren und vorrichtung zur bestimmung von strukturfehlern an laufenden textilen flächengebilden
US6131452A (en) * 1995-02-28 2000-10-17 Rhodia Filtec Ag Process and device for detecting structural faults of moving flat textile materials
DE102018103393A1 (de) * 2018-02-15 2019-08-22 Gerd Rebmann Abtastvorrichtung
DE102018103393B4 (de) 2018-02-15 2020-06-18 Gerd Rebmann Abtastvorrichtung

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Publication number Publication date
CH384352A (de) 1964-11-15

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