US3697686A - Cathode ray tube implosion protection system and method - Google Patents

Cathode ray tube implosion protection system and method Download PDF

Info

Publication number
US3697686A
US3697686A US84413A US3697686DA US3697686A US 3697686 A US3697686 A US 3697686A US 84413 A US84413 A US 84413A US 3697686D A US3697686D A US 3697686DA US 3697686 A US3697686 A US 3697686A
Authority
US
United States
Prior art keywords
band
envelope
tape
cathode ray
ray tube
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
US84413A
Other languages
English (en)
Inventor
Arnis Hildebrants
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Licensing Corp
Original Assignee
RCA Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
Application granted granted Critical
Publication of US3697686A publication Critical patent/US3697686A/en
Assigned to RCA LICENSING CORPORATION, TWO INDEPENDENCE WAY, PRINCETON, NJ 08540, A CORP. OF DE reassignment RCA LICENSING CORPORATION, TWO INDEPENDENCE WAY, PRINCETON, NJ 08540, A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: RCA CORPORATION, A CORP. OF DE
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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

  • a glass cathode ray tube envelope is provided with implosion-protection means by wrapping the peripheral portion of the envelope adjacent to the faceplate with a piece of fabric impregnated with an uncured thermosetting bonding material (e.g., B-stage epoxy resin), positioning afirst steel band around the tape, heating about two-thirds of the band to 200250 C., contacting the tape with the band while hot, to bond the tape to the glass envelope and band along about two-thirds of the periphery of the envelope, and tensioning and permanently mounting the band on the envelope by welding the ends together under tension while still hot so that, on cooling, the band tension is increased to a large value, e.g., 1,500 pounds, and then mounting a second steel band on the first band in the same manner as the first band but with the band joint on the opposite side of the envelope, to bond the tape to the envelope and first band along the remaining portion of the periphery thereof.
  • an uncured thermosetting bonding material e.g., B-stage epoxy resin
  • tension means that has proven satisfactory for small and medium tubes up to about 19V size (viewing diagonal dimension in inches) is the simple T-band type in which the envelope periphery is provided with one or more wrappings of cloth tape having a pressure type adhesive, and a steel tension band is mounted on the tape with a tension of several hundred pounds.
  • attempts to use this type of implosion protection on tubes of larger size (20V and above) have been unsuccessful, even when two steel bands were used.
  • the side wall of a glass cathode ray tube envelope adjacent to the faceplate is wrapped with a piece of fabric tape impregnated with a thermosetting bonding material, such as semicured epoxy resin; and a first steel band is positioned around the tape, heated by passing an electric current through the major portion thereof to a temperature sufficient to cure the bonding material, moved while hot into contact with the tape, to cure and bond the tape to the glass envelope and the band along the major portion of the tape, and then permanently mounted on the envelope by joining the ends together under tension while still hot, so that, on cooling, the band tension is increased to a relatively high value, preferably about l,500 pounds. Then, a second steel band is mounted on the first band, in the same manner as the first band but with the joint on the opposite side of the envelope, in order to cure'and bond the tape to the envelope and first band along the remaining portion of the tape.
  • a thermosetting bonding material such as semicured epoxy resin
  • FIG. 1 is an end view, looking toward the faceplate, of a cathode ray tube incorporating the present invention.
  • FIG. 2 is a side view, partly in axial section along line 2-2 of FIG. 1, of the tube of FIG. 1.
  • FIG. 3 is a partly schematic, plan view of an apparatus for mounting implosion protection means on a glass cathode ray tube envelope according to the invention.
  • the numeral 1 designates a glass cathode ray tube having an envelope or bulb 2 of generally rectangular shape with opposite major sides Ia and opposite minor sides lb.
  • the envelope 1 comprises a large cap or panel 3 sealed to the large end of a rectangular funnel 5 at 7, along a seal line A-A, and a tubular neck 9 sealed to the small end of the funnel S.
  • the tube 1 may be a commercial 22VABP4 having an overall panel diagonal dimension of 23.500 inches.
  • the cap 3 comprises a curved viewing faceplate 11 integral with a short cylindrical sidewall 13.
  • the outer surface of the side wall may include the usual maximum dimension rib or mold-match 15 at line 8-8 between the faceplate and the seal line, with the adjacent surfaces sloping away from the rib 15 at selected small angles C and D, as shown in FIG. 2.
  • the seal at 7 is an integral fused joint in monochrome or black-and-white TV tubes, and fritseal joint in standard color TV tubes having two-piece envelopes.
  • the envelope walls, particularly that of the cap 3 are substantially thicker, and hence, stronger in color tubes than in B & W tubes; and therefore, the implosion protection requirements are substantially higher in B & W tubes.
  • the present invention like other implosion-protection systems, is most applicable to and needed for, but not limited to, B & W tubes.
  • the envelope cap 3 in FIG. 1 is protected against implosion by means of two superposed steel tension bands 17 and 19 closely surrounding the side wall 13 of the cap 3, preferably centered on the mold-match 15, with the inner band 17 effectively bonded to the glass side wall 13 by an intermediate wrapping of fabric tape 21 impregnated with a thermosetting bonding material, e.g., epoxy resin, which has been cured in situ.
  • the tape 21 should be at least as wide, or wider than, each of the two bands 17 and 19.
  • the tape 21 may be 1 inch wide, and each band may have a width of threefourths inch and a thickness of 0.025 inch.
  • Each band consists of a single steel strap having its ends welded together, with the welded joints on opposite sides of the tube, which produces a symmetrical strain pattern in the glass envelope.
  • the net tension in each of the bands 17 and 19 is preferably about 1,500 pounds.
  • the total compression of the envelope is increased by adding the second band. Satisfactory implosion protection has been obtained with tape 21 impregnated with B-stage (semicured) epoxy resin, which is cured during the band mounting operation described below by heat from the heated bands 17 and 19.
  • FIG. 3 schematically shows an apparatus and method for mounting each of the two bands 17 and 19 on a rectangular cathode ray tube envelope 2.
  • the apparatus comprises a base plate or block 23 of electrical insulating material formed with a recess or nest 25 having an oval shape slightly larger than the envelope cap 3, and including four (e.g.) upstanding posts 27 and a vacuum cup 29 for supporting the tube 1 during the bonding operation in a position with the funnel 5 up, as shown in FIG. 3.
  • a pair of fixed welding electrodes 31 are mounted adjacent to one side 1a of the tube, and two fixed clamp members 33a and 33b are mounted at each side of the electrodes 31.
  • a movable welding electrode 35 is mounted for movement toward the electrodes 31, and two clamp members 37a and 37b are mounted for movement toward clamp members 33a and 33b, respectively.
  • Means 39 is provided for cutting the band adjacent to the electrode 35.
  • a pair of airoperated clamp-type heating electrodes 41 are used to supply electric heating current to the band.
  • the heating electrodes 41 are clamped to the band 17 in the general locations shown, separated by about twothirds of the periphery of the tube on the side opposite the welding electrodes 31.
  • electrodes 41 are removed, and clamp members 3311 and 37 a are actuated to grip the band 17.
  • the outer end of band 17 is immediately pulled tight to position the band in contact with the tape 21 along the two short sides lb and the bottom long side la of the tube 1.
  • the hot band contacts the tape in l to 1.5 seconds and the curing of the resin starts.
  • the band 17 has cooled to about 70 percent of its initial temperature.
  • the clamp member 37b is activated to grip the band, and the band is cut by means 39.
  • the welding electrode 35 is now activated to weld the two ends of the band together.
  • the movable elements 37a, 35 and 37b are retracted to release the welded band 21, and the vacuum cup 29 is raised to strip the band off the fixed elements 33a, 31 and 33b. All of the foregoing steps are completed while the band 17 is still hot, and the band shrinkage during subsequent cooling to room temperature subjects the band to a high net tension, preferably about 1,500 pounds.
  • the resin impregnant in the tape 21 is substantially cured and intimately bonded to the envelope glass and band 17 along more than two-thirds of the periphery of the tube, that is, between the points of attachment of the heating electrodes 41 to the band
  • the tube is rotated to position the welded joint in band 17 at the bottom in FIG. 3, and the second band 19 is mounted on top of the first band 17, by the same method as the first band.
  • a method of providing implosion-protection means on the side wall portion of a glass cathode ray tube envelope adjacent to the faceplate comprising the steps of:

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US84413A 1970-10-27 1970-10-27 Cathode ray tube implosion protection system and method Expired - Lifetime US3697686A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US8441370A 1970-10-27 1970-10-27

Publications (1)

Publication Number Publication Date
US3697686A true US3697686A (en) 1972-10-10

Family

ID=22184814

Family Applications (1)

Application Number Title Priority Date Filing Date
US84413A Expired - Lifetime US3697686A (en) 1970-10-27 1970-10-27 Cathode ray tube implosion protection system and method

Country Status (10)

Country Link
US (1) US3697686A (enrdf_load_stackoverflow)
JP (1) JPS5118311B1 (enrdf_load_stackoverflow)
AU (1) AU474122B2 (enrdf_load_stackoverflow)
BE (1) BE774511A (enrdf_load_stackoverflow)
CA (1) CA953346A (enrdf_load_stackoverflow)
DE (1) DE2153606A1 (enrdf_load_stackoverflow)
FR (1) FR2113173A5 (enrdf_load_stackoverflow)
GB (1) GB1349180A (enrdf_load_stackoverflow)
IT (1) IT942746B (enrdf_load_stackoverflow)
NL (1) NL7114718A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2382090A1 (fr) * 1977-02-28 1978-09-22 Rca Corp Perfectionnements apportes aux tubes a rayons cathodiques
DE3142162A1 (de) * 1980-10-24 1982-04-29 RCA Corp., 10020 New York, N.Y. Einrichtung zum anbringen eines spannbandes an einem gegenstand
US4415932A (en) * 1982-05-21 1983-11-15 Zenith Radio Corporation CRT Mounting and implosion-protection means and method
US5055934A (en) * 1990-06-05 1991-10-08 Thomson Consumer Electronics, Inc. Implosion protection means having mounting lug base-accommodating concavities therein

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2382090A1 (fr) * 1977-02-28 1978-09-22 Rca Corp Perfectionnements apportes aux tubes a rayons cathodiques
DE3142162A1 (de) * 1980-10-24 1982-04-29 RCA Corp., 10020 New York, N.Y. Einrichtung zum anbringen eines spannbandes an einem gegenstand
US4352226A (en) * 1980-10-24 1982-10-05 Rca Corporation System for applying and tensioning an implosion protecting band to a CRT with a tension between selected limits
US4415932A (en) * 1982-05-21 1983-11-15 Zenith Radio Corporation CRT Mounting and implosion-protection means and method
US5055934A (en) * 1990-06-05 1991-10-08 Thomson Consumer Electronics, Inc. Implosion protection means having mounting lug base-accommodating concavities therein

Also Published As

Publication number Publication date
JPS5118311B1 (enrdf_load_stackoverflow) 1976-06-09
CA953346A (en) 1974-08-20
FR2113173A5 (enrdf_load_stackoverflow) 1972-06-23
AU3435771A (en) 1973-04-12
DE2153606A1 (de) 1972-05-04
GB1349180A (en) 1974-03-27
AU474122B2 (en) 1976-07-15
BE774511A (fr) 1972-02-14
IT942746B (it) 1973-04-02
NL7114718A (enrdf_load_stackoverflow) 1972-05-02

Similar Documents

Publication Publication Date Title
US3190952A (en) Welded hermetic seal
US3162933A (en) Method of processing cathode ray tubes
US3697686A (en) Cathode ray tube implosion protection system and method
CA1135777A (en) Electron display tubes with pressure-bonded faceplate seal
US3512234A (en) Method of providing a clamping band around the bulb of a television picture tube and implosion-free tube manufactured by means of this method
JPH0590104A (ja) 固体電解コンデンサ
US2822512A (en) Rectifier assemblies
US3722044A (en) Fabrication of focus grill type cathode ray tubes
US3534233A (en) Hermetically sealed electrical device
US2827584A (en) Television picture tubes
US3597537A (en) Implosion-resistant cathode-ray tube utilizing a metal band
US3697825A (en) Radiation detector
JPS5855112B2 (ja) セラミツクスとＡｌとの鑞着構体
US1880571A (en) Glass to metal seal
US3553538A (en) Pressure contact semiconductor device
US3147361A (en) Vacuum tight joint and method of making such joint
US1834132A (en) Leading-in conductor
US2017647A (en) Electron discharge device
US2320204A (en) Method of stem construction for vacuum tubes
JPH0574372A (ja) 防爆形ブラウン管
JP3121140B2 (ja) 平板型陰極線管およびその製造方法
JPH0136276Y2 (enrdf_load_stackoverflow)
US1738169A (en) Rectifier
USRE23492E (en) Manufacture of the envelopes of
JPH0245951Y2 (enrdf_load_stackoverflow)

Legal Events

Date Code Title Description
AS Assignment

Owner name: RCA LICENSING CORPORATION, TWO INDEPENDENCE WAY, P

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:RCA CORPORATION, A CORP. OF DE;REEL/FRAME:004993/0131

Effective date: 19871208