US3278682A

US3278682A - Implosion-resistant cathode-ray tube with mounting brackets

Info

Publication number: US3278682A
Application number: US355857A
Authority: US
Inventors: Panis Constantius Jo Walterhus; Boer Floris De
Original assignee: US Philips Corp
Current assignee: US Philips Corp; North American Philips Co Inc
Priority date: 1963-04-03
Filing date: 1964-03-30
Publication date: 1966-10-11
Anticipated expiration: 1983-10-11
Also published as: ES298182A1; BE646060A; CH418473A; DE1224843B; AT242761B; DK107822C; NL291096A; GB1005485A

Description

C. J. IMPLOS ION-RE W. PANIS ETAL 3,278,682 SI NT CATHODE-RAY TUBE WITH MO ING BRACKETS Filed March 30, 1964 Oct. 11, 1966 INVENTOR. CONSTANTIUS J.W. PANIS FLORIS DE BOER United States Patent 3,278,682 IMPLOSION-RESISTANT CATHODE-RAY TUBE WITH MOUNTING BRACKETS Constantius Johannes Walterhus Panis, and Floris De Boer, both of Emmasingel, Eindhoven, Netherlands, assignors to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware Filed Mar. 30, 1964, Ser. No. 355,857 Claims priority, application Netherlands, Apr. 3, 1963,

3 Claims. (cl. 17s-7.s)

This invention relates to cathode-ray tubes for television display, comprising a glass bulb having its zone adjoining the image surface surrounded by a metal band which exerts substantially no pressure on the bulb, the space between the band and the glass bulb of the tube being filled with a solid filler, and lugs being provided for securing the tube in a cabinet.

In known tubes, the lugs have sometimes been fixed under a metal band which is clamped around the bulb.

It is also known that the lugs can be fixed in a layer of synthetic substance, but in this case a metal band was not provided and the layer of synthetic substance had been reinforced by the addition of glass fibres.

Known embodiments have several disadvantages. Unless a metal band is present, it is diflicult to provide the lugs with sufficient accuracy since there is no accurate point of reference. is not accurate enough due to the great tolerances of the glass, which amount to a few millimeters in large size tubes.

When use is made of a clamping band the lugs in the form of rectangularly bent plates can have a fiat portion clamped under the strip. During the tightening of the clamping device, however, the lugs are apt to be shifted in position due to the tensioning of the band.

When use is made of a metal band it seems eflicient to weld the lugs to the band, but in this case the distance between the lugs and the front of the glass window is not accurately determined since the tolerances of the glass, especially of the window, now also play a part, that is to say the convexity of the window may vary. Another disadvantage consists in that the metal band, if it consists of a single ring which must be slipped from the front of the tube onto the portion of the bulb of the largest crosssection, must have a greater width if the rectangularly bent lugs are previously welded to the inner side of the ring. Consequently, a considerably larger gap locally exists between the bulb and the ring so that a much larger quantity of filler is required, which is expensive, especially if the filler is a synthetic substance. Moreover, the tube will then have a greater outer diameter. Welding the lugs to the outer side of the hand does not enter into account for the same reason and also from an aesthetical point of view.

The welding operation has a further limitation in that stresses can be produced in the band and cause it to warp when taken out of the welding jig, as a result of which the lugs are no longer co-planar. The securement of the lugs to the band has still further disadvantages, as will appear hereinafter.

When use is made of a metal band, the said disadvantages are completely avoided if, according to the invention, the portion of each of the lugs located between the band and the bulb is held solely by the solid filler. This portion of each lug is then preferably provided with a few peripheral recesses in order to increase the hold of the filler on this portion. Although the filler itself is thus not reinforced, it has been found that nevertheless a perfectly reliable and sufiiciently rigid attachment of the lugs can be obtained.

A reference on the glass of the bulb Since the lugs can be provided after the metal band has been arranged around the bulb, the gap between the bulb and the band need not be particularly wide since the portion of the bulb having the greatest transverse dimensions need no longer slide along the portions of the lugs located inside the band. Since the material of the lugs is com-. paratively thick (2.5 mm.) and mostly four lugsare provided, this makes a considerable difference for the width of the gap at the lugs. The saving in filler is consequently considerable.

The invention will now be described, with reference to the accompanying diagrammatic drawing, in which:

FIGURE 1 shows part of a cathode-ray tube in accordance with the invention;

FIGURE 2 is a perspective view of a lug;

FIGURE 3 shows a detail of a band of other design.

FIGURE 4 shows a detail of the bulb prior to pouring the filler into the gap between the band and the bulb.

In the figures, the reference numeral 1 denotes a glass window of a cathode-ray tube which is sealed at 3 to a glass cone 2. The cone 2 is coated with a thin layer 4 consisting of glass tissue impregnated with a synthetic substance.

A band 5, which has the shape of a profiled metal ring, is arranged around the bulb so that the bulb engages an edge 6 of the band 5. As a result, this edge conforms to the surface of the window so that the tolerance deviations of the glass cause deformation of the band. Consequently, lugs secured to the band would leave their planes and, upon fastening by screws in the receiver cabinet, would give rise to deformation of the band and to stresses in the bulb and in the receiver cabinet.

A direct contact between the edge 6 and the bulb 1 is avoided by previously coating the glass with a layer of glue or providing spacers between the edge 6 and the glass. At its top the band 5 has a portion 7 of constant crosssection. The cross-section of the portion 7 must exceed the greatest transverse dimensions of the bulb.

The tube is suspended by means of lugs 8 comprising rectangularly bent metal plates each having an aperture 10. If the portion 9 of the lugs 8 were welded to the band beforehand the diagonal of the portion 7 would have to be greater for twice the thickness of the material of the lugs. As a result, the gap between the band 5 and the bulb 1 would locally become equally wider so that the content of the gap and hence the quantity of filler 11 would be much greater. Besides, the reinforcement of the bulb becomes greater as the gap has a smaller width.

FIGURE 2 shows the manner in which the portion 9 of each lug is bent cylindrically and provided with recesses 12, so that the filler 11 has a better hold on the lugs. The filler is preferably a synthetic substance satisfactorily adhering to the glass and the band and hence also to the material of the lugs. Such fillers may be those disclosed in US. Patent 3,206,056 and in copending US. application Serial No. 170,639, filed February 2, 1962.

It is also possible, however, to use fillers which adhere poorly or not at all, such as sulphur, concrete or similar substances. In this case the recesses in the portions 9 of the lugs are necessary and may preferably have a greater depth. In order to avoid disengagement of the band from the tube when using such fillers, means of anchoring, for example in the form of a plurality of protuberances or ribs 13, could be provided in the portion 7 of the band (see FIGURE 3).

In order to prevent leakage at the edge 6 when the filler is poured into the gap, the tube is placed, as shown in FIGURE 4, in a mold or a support 14 in which provision is made of a flexible sealing edge 15, consisting of sponge rubber, and also of spacers 16. The bulb is pulled downwards by means of suction devices (not shown) placed on the center of the window and connected to a vacuum line. Since the window of the bulb then comes to bear on the spacers 16 the flexible ring is depressed only with a slight force, so that excessive deformation of the band does not occur and yet the gap between the edge 6 and the glass is satisfactorily sealed notwithstanding the fact that, as viewed along the circumference, the edge 6 is arcuated since it follows the curvature of the edge of the display screen. The flexible ring 15 has a greater thickness on its outer side, resulting in a more satisfactory seal being obtained.

During pouring the filler 11 in the gap, the lugs 8 are accurately fixed in their correct position by means of jigs 17 and, where necessary, pins 18 fitting in the apertures of the lugs, completely independent of the band 5. Since the distance between the lugs and the base plate 14 is accurately determined, as is that between the upper sides of the spacers 16 and this base plate, the distance H between the lugs and the edge of the screen is also fixed, completely independent of the tolerances of the glass or of deformation of the band.

What is claimed is:

1. A cathode-ray tube comprising a glass envelope having a cone portion and an adjoining window portion, a rigid band surrounding the juncture between the window portion and the cone portion and spaced therefrom thereby exerting substantially no pressure on the envelope, a solid filler material filling the space between the band and the envelope, and mounting members for securing the tube to a housing, said mounting members each comprising a rectangularly-bent metal plate one portion of which is provided with an aperture, one portion of said metal plate being securely positioned in said filler material, the other portion of said metal plate extending radially beyond the filler material.

2. A cathode-ray tube comprising a glass envelope having a cone portion and an adjoining window portion, a rigid band surrounding the juncture between the Window portion and the cone portion and spaced therefrom thereby exerting substantially no pressure on the envelope, a solid filler material filling the space between the band and the envelope, and mounting members for securing said tube to a housing, said mounting members each comprising a rectangularly-bent metal plate one portion of which is provided with an aperture, one portion of said metal plate having reentrant portions and extending into said filler material and being securely position therein, the other porton of said metal plate extending radially beyond the filler material.

3. A cathode-ray tube comprising a glass envelope having a cone portion and an adjoining window portion, a rigid metal band surrounding the juncture between the window portion and the cone portion and spaced therefrom thereby exerting substantially no pressure on the envelope, a solid filler material adhering poorly to glass and metal filling the space between the band and the envelope, said metal band having protruding portions on the side adjacent the Window portion to anchor the band in the filler material, and mounting members for securing the tube to a housing, said mounting members each comprising a rectangularly-bent metal plate one portion of which is provided with an aperture, one portion of the metal plate being securely positioned in said filler mate rial, the other portion of said metal plate extending radially beyond the filler material.

References Cited by the Examiner UNITED STATES PATENTS 2,851,679 9/1958 Wayne 1787.8 2,874,017 2/1959 Henry et al. 2202.1 3,220,593 11/1965 Powell et al 2202.1

FOREIGN PATENTS 607,500 10/ 1960 Canada.

DAVID G. REDINBAUGH, Primary Examiner.

R. L. RICHARDSON, Assistant Examiner.