US3708369A - Method of providing an anti-implosion clamping band around the envelope of a picture tube - Google Patents

Method of providing an anti-implosion clamping band around the envelope of a picture tube Download PDF

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Publication number
US3708369A
US3708369A US00815579A US3708369DA US3708369A US 3708369 A US3708369 A US 3708369A US 00815579 A US00815579 A US 00815579A US 3708369D A US3708369D A US 3708369DA US 3708369 A US3708369 A US 3708369A
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United States
Prior art keywords
frame
envelope
band
tube
heated
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Expired - Lifetime
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US00815579A
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English (en)
Inventor
T Doreleijers
H Bongenaar
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US Philips Corp
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US Philips Corp
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Application filed by US Philips Corp filed Critical US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/86—Vessels; Containers; Vacuum locks
    • H01J29/87—Arrangements for preventing or limiting effects of implosion of vessels or containers

Definitions

  • the invention relates to a method of providing an antiimplosion clamping band around the envelope of a television picture tube.
  • the invention relates particularly to a method in which a band frame, the aperture of which is formed in accordance with the cross-section of the region situated between the plane of the picture screen and the sealing seam of picture screen and cone, is provided around the envelope in a direction along the longitudinal axis of the tube.
  • the invention furthermore relates to a picture tube provided with such a clamping band.
  • a method is known from British Pat. 977,654 in which an oversize frame is positioned around an envelope of a picture tube, the intermediate space being then filled with a filler.
  • This method has the advantage that the tolerances of the envelope and the frame do not influence the provision of the frame or the anti-implosion effect.
  • the comparatively large quantity of filler, in general a synthetic resin is expensive while said method is restricted to a frame which borders the face-plate of the envelope. Since no noteworthy pressure is exerted on the envelope, said safeguarding is insufiicient in the case in which it is desirable that the part of the wall situated between the mould match line and the face-plate of the window portion projects outside the frame.
  • Another anti-implosion protection is obtained by providing a clamping band around the widest part of the envelope.
  • the clamping band is tightened with a force exceeding 700 kg., the said restriction is not present.
  • an uneven pressure over the circumference of the envelope may be set up in tightening the clamping band as a result of the friction which the band experiences particularly at the corners of a rectangular screen.
  • a method of providing an antiimplosion clamping band in which a band frame, the aperture of which is formed in accordance with but smaller than the cross-section of the region of the envelope situated between the picture screen plane and the sealing seam of picture screen and cone, is provided around the envelope in a direction along the longitudinal axis of the tube, if, according to the invention, at least the part of the envelope which contacts the frame is covered with a heat insulating layer, the frame is heated, prior to being provided on the envelope, to such a temperature that upon cooling the frame on the envelope, the material of the frame is elongated at least to the yield point, after which the space remaining between the envelope and the frame is filled at least partly with an adhesive.
  • the insulating layer may consist, for example, of a synthetic material, for example, polyvinyl acetate, or of a hardening synthetic material, for example, epoxy resin. If the heat insulating layer consists of an epoxy resin, the hot band is preferably provided prior to the hardening of the resin.
  • the insulating layer protects the cold envelope from direct contact with the hot frame, so that also in the most unfavorable combination of tolerances no cracks occur upon cooling the frame on the envelope notwithstanding the fact that the frame has to be heated to 400 to 450 C. to reach the yield point of the material of the frame.
  • the adhering material with which the space remaining between the frame and the envelope is filled may consist of an epoxy resin, but other known adhering materials, for example, polyester, urea, sulphur and the like, may also be used.
  • the frame is preferably made so wide that it extends partly over the welding seam. This part is free from the surface of the glass, as a result of the particular shape of the envelope. This free edge of the frame is fully or partly filled with adhering material.
  • a tensile force of at least 500 to 700 kgms. must be present in the frame. This is obtained by reinforcing the edge of the frame situated near the mould match line by means of a separate steel band or by folding said edge in two.
  • the cross-section of the frame must be at least 16 to 22 sq. mm. when the yield point lies at approximately 33 kgms./ sq. mm.
  • the tensile force in the frame hence is 660 kgms. independent of the tolerances.
  • FIG. 1 is a cross-sectional view of an envelope of a color television tube, while 'FIGS. 2, 3, 4, and 6 are cross-sectional views of various embodiments of band frames, and
  • FIG. 7 diagrammatically shows an arrangement for providing a hot band frame around a picture tube, which is otherwise fully finished.
  • a glass window for a color picture tube is welded to a cone 2 by means of a layer of glaze 3.
  • a phosphor screen 4 and a shadow mask 5 are provided in the window portion 1.
  • a heat insulating layer 6 is provided consisting of polyvinyl acetate or epoxy resin, on which the clamping frame 7 is provided.
  • an extra reinforcing band 8 is provided.
  • the remaining space between the frame and the envelope is filled with an adhering material 18 up to the welding seam '3.
  • the glaze Welding seam 3 is preferably not covered with adhering material so as to avoid damage to the seam due to the difference in co efficients of expansion of adhering material and glass.
  • the adhering material 18 can be fully provided up to the upper edge of the frame 7.
  • the cross-section of the frame 7 may have different shapes as is shown in FIGS. 2 to 6.
  • a reinforcing band '8 is provided around the frame.
  • the edge of the frame 10 is folded outwards, in FIG. 4 inwards to form a band 9.
  • a clamping band 12 is arranged in the pleat of the frame 10 so that the band 12 is clamped by the folded edge 11.
  • FIG. 6 a similar construction is used, this time on the inside of the frame 10.
  • the cross-sections of the frames of these figures are, for example, 50 mms. high 0.8 mm. wide, a height of 25 mms. engaging the envelope and being hence mainly decisive of the pressure exerted on the envelope by the frame 7, 10.
  • the cross-section of the band 8, 12 is, for example, 10 x 0.8 mms.
  • Heating is then switched off.
  • the material of the insulating layer 6 softens and even burns partly. It is found, however, that said layer has such a heat insulating effect that the temperature shock which the envelope experiences during providing the hot band is sufficiently clamped to prevent cracking of the glass.
  • the remaining parts of the insulating layer solidify after cooling or harden by the heat of the frame 7, and prevent the frame 7 from bursting off the envelope before the adhering material 18 poured in the space between the envelope and the frame has hardened.
  • the inside of the frame is preferably roughened to improve the adhesion.
  • the band For reaching the yield point of the steel of the frame 7 and the band 8 it is necessary for the band to shrink at least 3 mms. with an inner circumference of approximately 1600 mms., which must hence be the case in the most unfavourable combination of the tolerances, i.e. the smallest envelope with the widest frame.
  • the tolerance for the circumference of the envelope is 10.5 mm., so totally 1 mm. and for the frame totally only 0.33 mm.
  • the frame may also have different crosssections and, if desired, also have the shape of a narrow thick annular band.
  • a method for providing an anti-implosion clamping band around the envelope of a television picture tube comprising, forming from material having a positive temperature coefficient of expansion a clamping frame having an aperture shaped in accordance with the crosssectional area of said envelope, said frame being sufliciently smaller than the cross-sectional area of said envelope that expansion of the frame to the size of the envelope stresses the material of the frame beyond its yield point, heating said frame without simultaneously heating said envelope to a temperature of 400 C.
  • a method as claimed in clalm 1 wherein said layer 5 3,508,310 4/1970 Eisses 178 7 82 X of heat insulating material further consists of an epoxy resin CARL D. QUARFORTH, Primary Examiner '5.
  • a method as claimed in claim 1 wherein said layer NELSON, ASSiStflIlt er of heat insulating material further consists of polyvinyl acetate. 156-295, 330

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  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US00815579A 1968-04-13 1969-04-14 Method of providing an anti-implosion clamping band around the envelope of a picture tube Expired - Lifetime US3708369A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL686805299A NL154864B (nl) 1968-04-13 1968-04-13 Werkwijze voor het aanbrengen van een implosiebeveiligingsband om de ballon van een televisiebeeldbuis en een door middel van deze werkwijze vervaardigde televisiebeeldbuis.

Publications (1)

Publication Number Publication Date
US3708369A true US3708369A (en) 1973-01-02

Family

ID=19803335

Family Applications (1)

Application Number Title Priority Date Filing Date
US00815579A Expired - Lifetime US3708369A (en) 1968-04-13 1969-04-14 Method of providing an anti-implosion clamping band around the envelope of a picture tube

Country Status (9)

Country Link
US (1) US3708369A (de)
AT (1) AT284217B (de)
BE (1) BE731439A (de)
CH (1) CH489898A (de)
DE (1) DE1913566C3 (de)
ES (1) ES365929A1 (de)
FR (1) FR2006186A1 (de)
GB (1) GB1204109A (de)
NL (1) NL154864B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2405560A1 (de) * 1973-02-12 1974-08-15 Philips Nv Elektronenstrahlroehre mit implosionsschutz
US3845530A (en) * 1972-10-10 1974-11-05 Rca Corp Method for rendering cathode-ray tube more resistant to implosion and product thereof
US5216513A (en) * 1991-07-31 1993-06-01 Thomson Consumer Electronics, Inc. Cathode-ray tube having a shrinkfit implosion protection band with faceplate panel compensating means

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2173782B1 (de) * 1972-03-02 1974-08-02 Orega Cifte

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2785820A (en) * 1952-06-28 1957-03-19 Owens Illinois Glass Co Controlling implosions in cathode ray and other tubes
GB966206A (en) * 1961-11-10 1964-08-06 Cie Ind Francaise Tubes Elect Improvements in or relating to anti-implosion devices for cathode ray tubes
US3350154A (en) * 1964-12-18 1967-10-31 Owens Illinois Inc Reinforced cathode-ray tube and face plate therefor
DE1280424B (de) * 1965-11-01 1968-10-17 Standard Elektrik Lorenz Ag Verfahren zur Ummantelung von Bildroehren mit einem Implosionsschutzrahmen und Vorrichtung zur Durchfuehrung des Verfahrens

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3845530A (en) * 1972-10-10 1974-11-05 Rca Corp Method for rendering cathode-ray tube more resistant to implosion and product thereof
DE2405560A1 (de) * 1973-02-12 1974-08-15 Philips Nv Elektronenstrahlroehre mit implosionsschutz
US5216513A (en) * 1991-07-31 1993-06-01 Thomson Consumer Electronics, Inc. Cathode-ray tube having a shrinkfit implosion protection band with faceplate panel compensating means

Also Published As

Publication number Publication date
DE1913566A1 (de) 1969-10-30
GB1204109A (en) 1970-09-03
ES365929A1 (es) 1971-03-16
FR2006186A1 (de) 1969-12-19
NL154864B (nl) 1977-10-17
AT284217B (de) 1970-09-10
CH489898A (de) 1970-04-30
DE1913566C3 (de) 1985-08-01
NL6805299A (de) 1969-10-15
BE731439A (de) 1969-10-13
DE1913566B2 (de) 1978-09-14

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