US3573368A

US3573368A - Cathode-ray tube implosion guard with beeswax annular metal frame and metal band

Info

Publication number: US3573368A
Application number: US721486A
Authority: US
Inventors: Friedrich Kober
Original assignee: US Philips Corp
Current assignee: US Philips Corp
Priority date: 1967-05-11
Filing date: 1968-04-15
Publication date: 1971-04-06
Anticipated expiration: 1988-04-06
Also published as: CH479951A; ES353713A1; AT278918B; NL6806409A; DE1512385B2; DE1512385A1; FR1567427A; BE714933A; GB1172342A

Abstract

An implosion resistant cathode-ray tube for television display employing a first metal band surrounding and secured to the envelope adjacent the screen and a second metal, preferably steel, band around the first band and subjected to a large tensile stress. The second band glides over the first and to equalize tension at the corners, a lubricant is applied between the bands to reduce function between the bands. As a lubricant, beeswax is preferred.

Description

United States Patent 72] inventor Friedrich Kober Aachen, Germany [21] Appl. No. 721,486

[22] Filed Apr. 15, 1968 [45] Patented Apr. 6, 1971 [73] Assignee U. S. Philips Corporation New York, N.Y.

[32] Priority May 11, 1967 [33] Germany [54] CATHODE RAY TUBE IMPLOSION GUARD WITH BEESWAX BETWEEN ANNULAR METAL FRAME AND METAL BAND 1 Claim, 3 Drawing Figs.

52 U.S.Cl. l78/7.8, l78/7.9

[5l] InLCl. l-l0lj 29/82 [50] Field ofSearcli l78/7.8, 7.9

[56] References Cited UNITED STATES PATENTS 2,970,311 1/1961 Napoli et a1 l78/7.8 3,278,682 10/1966 Panis et al l78/7.8

Primary Examiner-Robert Segal Attorney-Frank R. Trifari ABSTRACT: An implosion resistant cathode ray tube -for television display employing a first metal band surrounding and secured to the envelope adjacent the screen and a second metal, preferably steel, band around the first band and subjected to a large tensile stress. The second hand glides over the first and to equalize tension at the corners, a lubricant is applied between the bands to reduce function between the bands. As a lubricant, beeswax is preferred.

PATENTEU APR Glen 3573; 368

Fig.3

INVENTOR.

FRIEDRICH KOBER AG T CATHODE RAY TUBE IMPLOSION GUARD WITI-I BEESWAX BETWEEN ANNULAR METAL FRAME AND METAL BAND The invention relates to a television display tube having an implosion guard which consists of a metal ring which is stuck, for example, to the tube, and of at least one steel band arranged around the ring and subjected to a large tensile stress.

As is known, television display tubes must be provided with an implosion guard which prevents'the glass body from being completely destroyed when air suddenly penetrates into the tube. As is known, in such an implosion guard, annular frames of a corrosion-resistant sheet iron are used which are provided with reinforming ribs and with lugs at the corners for securing the display tube in the cabinet of a receiver. These bands are pressed over the tube from the neck as far as the mould match line and are surrounded by at least one steel band subjected to a large tensile stress. I

Experiments have shown that the implosion guard of such television display tubes is effective when annular frames and clamping bands are used and is based on the occurrence of force components directed approximately along the diagonals. However, great difficulty was involved in determining the pressure forces which were absolutely sufficient to prevent an implosion. The experiments for determining these forces at the comershave shown that these forces can be greatly different at the separate corners of a'tube, since the clamping band, when stretched around the annular frame, is subjected to friction, especially at the areas at which the direction of the steel band strongly changes, i.e. at the' comers of a rectangular television display tube.

The frictional forces are produced between the steel band and the annular frame or between separate steel bands if several juxtaposed steel bands are stretched around the annular frame. The invention is based on recognition of the fact that it is essential to provide the steel bands on the annular frame so that the forces produced at the separate corners of the display tube are the same. According to the invention, this may be achieved by reducing the coefficients of friction between the annular frame and the steel band or between the separate steel bands. For this purpose, according to the invention, a conditioner, preferably beeswax, is applied between the metal bands, at least near the corners of the display tube, i.e. at areas at which a great frictional force is to be expected. With the use of two juxtaposed steel bands, the conditioner may be applied both between these steel bands and between the lower steel band and the annular frame near the corners. If the conditioner is applied in manner, the coefficient of friction at the critical points is reduced to such an extent that a uniform distribution of force at the comers of the display tube I is obtained without the stretching machine sliding off along the bands. However, it is also recommendable to apply a conditioner to the inner sides of the beginning and the end of a band sliding over each other and clamped by the stretching device, because the tensile force produced in the band by the stretching device is a maximum when the friction between the band and the stretching device is a maximum and that between the beginning and the end of a band is a minimum.

Known steel bands are generally manufactured for packing applications and are lubricated with oil'in order to permit the bands to more readily sliding over each other and to reduce the coefficients of friction. This step is sufficient for the normal packing applications, it is true, since it is not essential that a given pressure should be exerted on the corners of a packed article; it is only important that the'packing should be kept intact. As already stated, however, it is of major importance with the use of such steel bands for protecting television display tubes from implosion that equal forces should be produced at the separate comers of the tube and that these forces should lie within certain limits during the stretching operation, for example, between 900 and 1000 kgs/corner.

The present invention therefore has the advantage that the coefficient of friction between clamping band and annular frame or between band and band can be reduced to such extent that a uniform distribution of forces over the four corners FIG. 2 shows on an enlarged scale a part with two comers of a an approximately rectangular television display tube; and

FIG. 3 shows the comer of a television display tube of FIG. 1, the implosion guard now consisting of an annular frame and two juxtaposed steel bands.

Referring now to FIG. 1, reference numeral 1 denotes the television display tube,'viewed from the screen side, over the periphery of which is passed an annular frame 2 which is provided at its comers with lugs 3 for securing the tube in the cabinet of a receiver and is surrounded by a steel-clamping band 4 (shown in dotted lines).

In FIG. 2, reference numeral 1 also denotes the television display tube, reference numeral 2 the annular frame,

reference numeral 3 the lug and reference numeral .4 the steelclamping band. This FIG. shows a television display tube the screen of which is located on the front side of the cabinet of limited by transverse lines 7 between the parts sliding with friction over each other, i.e. between the annular frame 2 and the steel band 4 or between the annular frame 2, the steel band 4 and the steel band 6. These conditioners cause the coefficients of friction between the various bands to be reduced to such an extent that the bands can be pulled across the comers without difficulty and that equal forces are produced at all the comers of the television display tube.

The use of such conditioners also affords the advantage that the steel bands need not be pulled so tightly that they are liable to break.

I claim:

I. A cathode-ray tube for television display having a substantially rectangular window portion and a conical portion adjoining the window portion,'an annular metal frame surrounding and secured to the conical portion adjacent the juncture thereof with said window portion, a metal band under tensile stress surrounding the annular metal frame, and a lubricant consisting of beeswax between the metal band and the metal frame to reduce the coefficient of friction therebetween whereby the band can be drawn over the frame and the distribution of force at the comers is made uniform.

Claims

1. A cathode-ray tube for television display having a substantially rectangular window portion and a conical portion adjoining the window portion, an annular metal frame surrounding and secured to the conical portion adjacent the juncture thereof with said window portion, a metal band under tensile stress surrounding the annular metal frame, and a lubricant consisting of beeswax between the metal band and the metal frame to reduce the coefficient of friction therebetween whereby the band can be drawn over the frame and the diStribution of force at the corners is made uniform.