Environmentally Controlled Video Tube Socket Assembly Utilizing Spark Gap Unit

Abstract

This invention is directed to a tube socket assembly including an environmentally sealed spark gap unit for protection against high voltage surges which may be either regular atmosphere, evacuated or gas filled. The tube socket assembly is composed of a tube receiving unit and a spark gap unit. The tube receiving unit has a socket body formed of insulating material with a plurality of terminal pin-receiving openings. A current conducting contact is mounted within each of the terminal pin-receiving openings and current conducting leads extend from these contacts through the socket body for external connection. The spark gap unit has an encapsulated housing of insulating material which contains a conducting plate and a plurality of spaced electrodes. An insulating wafer separates the electrodes from the plate and has a plurality of openings aligned with each of the electrodes. Terminal means are provided for electrically connecting the electrodes to the current conducting leads of the tube receiving unit.

Description

BACKGROUND OF THE INVENTION

This invention is directed to tube sockets for use in connecting cathode ray tubes, video tubes and the like. In particular, this invention is directed to a tube socket assembly having a spark gap unit for protecting the tube from high voltage surges.

In the present state of the art, tube sockets generally consist of a molded insulating body having a plurality of terminal pin-receiving openings with female terminal contacts mounted in each of the terminal pin-receiving openings. A surge protection system generally known as a multiple spark gap is provided within these molded insulating bodies and generally consists of a collecting or ground ring mechanically affixed adjacent the female terminal such that a voltage surge of predetermined amplitude will be discharged through the ground ring to a ground potential. Often, these sockets include resistors contained wthin the molded insulating body and electrically connected in series with the terminals and associated with the connecting wires. The purpose of the multiple spark gap device provided in the socket is to provide isolated parallel circuits to ground for removing flashover currents that would otherwise have a detrimental effect on the electronic components used in the television and video circuits. The function of the resistors used inseries with the terminals is to provide a damper to the transient voltages. Thus, these resistors act as an equivalent RC filter for high voltages appearing on the various tube pins to thereby provide a degree of isolation and serve as current limitors for the supply circuit whenever the spark gap is conducting.

The problem encountered in using the above described sockets is that they are subject to environmental contamination and mechanical instability which limits their reliability and the repetitive performance of the spark gap operation. Environmental contamination can be caused by such factors as dust and humidity that creates an electrical tracking path with a resultant change in the firing potential of the spark gap. Current and prior tube socket assemblies use the mating female terminals as one of the spark gap electrodes, and as a consequence insertion of the tube into these mating female terminals often causes a change in the spacing between the spark gap electrodes.

To overcome the limitations and disadvantages of the above described prior structures, we have conceived a spark gap device in which the mechanical, electrical and environmental characteristics can be precisely controlled and maintained. Our invention in its preferred form has no mechanical interdependence of the spark gap unit with the terminals of the socket. Thus, we are able to duplicate the desirable features of the socket, spark gap, resistor connecting lead arrangement, which heretofore has been a complex array of components assembled together in a molded insulated housing. Further, our spark gap unit is environmentally sealed to protect it from environmental contamination.

SUMMARY OF THE INVENTION

Our invention comprises a molded insulating socket body having terminal pin-receiving terminals and an independent spark gap unit which is environmentally sealed. The socket body and spark gap device are preferably mounted on a printed circuit board which may include an edge connector with terminals for wire connection.

Accordingly, one object of this invention is to provide a tube socket having an independent tube receiving unit and spark gap unit to eliminate the interdependence of the assembled components and provide reliable functioning of the tube socket.

Another object of this invention is to provide an environmentally sealed spark gap unit with either regular atmosphere or gas filled or be evacuated and operated in a vacuum to provide a specific internal environment.

Another object of this invention is to provide separate tube receiving units and spark gap units to simplify the assembly and effect substantial manufacturing cost savings.

Another advantage of this invention is to provide the electrodes of the spark gap unit with spherical form to facilitate the firing and extinguishing of the arc across the spark gap.

A further object of this invention is to provide a spark gap device having electrodes held in a predetermined space relationship.

Other objects, advantages and uses will appear or be readily appreciated by one skilled in the art from the following description and from the drawings.

DESCRIPTION OF DRAWING

For a better understanding of this invention, reference may be made to the accompanying drawing, in which:

FIG. 1 is a perspective view showing the preferred embodiment of this invention with the spark gap unit depicted prior to assembly on the terminal board;

FIG. 2 is a partial top elevational view of the preferred embodiment of this invention;

FIG. 3 is a cross sectional view of the preferred embodiment of this invention taken along the line 3--3 of FIG. 2 and looking in the direction of the arrows; and

FIG. 4 is an exploded view of the components used to form the spark gap unit.

DESCRIPTION OF PREFERRED EMBODIMENT

There is shown in FIG. 1, a tube socket assembly which embodies the principles of this invention and is generally designated by the reference numeral 10. Tube socket assembly 10 has two major components -- tube receiving unit 12 and saprk gap unit 14.

Tube receiving unit 12 has a socket body 16 formed of insulating material and is shaped with a circular base or collar portion 18 and upstanding neck portion 20. Socket body 16 is preferably molded into a one-piece structure with a plurality of terminal pin-receiving openings 22 provided in the neck portion and a central aperture 24 having a conventional pin orientation slot 26.

There is mounted in each of the terminal pin-receiving openings 22 a current conducting contact 28 having a tubular body portion 30 with an upper open end 32 for receiving a terminal pin therein. A current conducting lead 34 is electrically connected to each of the current conducting contacts 30 and extends down through a passageway 36 formed in the base portion 18 of the socket body 16.

The spark gap unit 14 is enclosed in an encapsulated housing 40 and is made up of the components illustrated in FIG. 4. A wafer of insulating material 42 having a ring shaped configuration is employed to separate a plurality of space electrodes 44 from a conducting plate 46 shaped in the form of a collecting ring. The wafer 42 which could be made, for example, from a molded thermoplastic material has a plurality of spark gap openings 48 corresponding to the number of electrodes 44.

The electrodes 44 are made of a current conducting material such as copper and could be formed in a stamping operation in the manner depicted in FIG. 4 with the electrodes 44 attached as radial spokes in a predetermined angular relation between an inner and outer ring portion 50 and 52. Using such an arrangement, the electrodes can be maintained in their desired spatial relationship as they are secured to one side of the insulating wafer 42. Once the electrodes are secured to the insulating wafer 42 the inner and outer rings 50, 52 and the dotted radial portion 54 would be broken off.

The encapsulated housing 40 is formed by bonding a pair of insulating disks 60, 62 to the opposite sides of insulating wafer 42. The insulating disks 60 and 62, which could be made, for example, of mylar or tedlar, have substantially the same inside and outside diameters as the insulating wafer 42. The insulating disks 60, 62 may be either sealed to the insulating wafer 42, or an encapsulating compound could be applied around their inner and outer peripheral edges leaving only the tabs or terminals 64 of electrodes 44 and the single terminal 66 of collecting ring 46 uninsulated. To provide a specific internal environment the encapsulated housing 40 may be either evacuated or gas filled. However, it is noted sealing the housing 40 with regular dry atmosphere has produced quite satisfactory results.

As is apparent from the foregoing description, the tube receiving unit 12 and spark gap unit 14 are mechanically independent of each other which permits the replacement of either unit should it fail and eliminates the interdependence of the components in these two units to thereby provide more reliability. To assemble the two units together, the spark gap unit is placed over the neck portion 20 so that it rests on the collar portion 18, and its terminals 64 are positioned to coincide with the outer leg 70 of current conducting leads 34. The terminals 64 are then electrically connected to leads 34 as by soldering.

In the preferred embodiment the combined tube receiving spark gap sub-assembly is mounted on a terminal board 74 with terminals 64, 66 and 70 extending through preformed apertures 76.

One distinct advantage of using terminal board 74 is that resistors or other electrical components could be mounted thereon and electrically connected to the terminals 64, 66 and 70 in any desired manner. Alternatively terminal board 74 could be substituted by a printed circuit board. An edge connector 78 having male terminals 80 is provided on one margin of terminal board 74 to provide a male terminal for each of terminals 64 and 70, and any associated electronic components mounted on the terminal board.

To facilitate the firing and extinguishing of an arc between the electrodes 64 and collecting ring 46, each electrode 64 may be provided with a spherical portion 82 extending into the aligned spark gap opening 48 and the collecting ring 46 may be provided with a corresponding number of spherical portions 84 extending into the opposite end of each spark gap opening 48. Collecting ring 46 and electrodes 64 are preferably die cut from a very thin, tin plated copper sheet of the order of 0.01 inch in thickness, having conical deformations at selected intervals to provide the spherical portions 82 and 84.

Claims

I claim:

1. A tube socket assembly comprising a tube receiving unit and a spark gap unit; said tube receiving unit including a socket body formed of insulating material and having a plurality of terminal pin-receiving openings, and a current conducting contact within each said terminal pin-receiving openings, one end of each of said contacts disposed to receive a terminal pin of an electronic tube, and a current conducting lead extending from each of said contacts through said socket body; said spark gap unit including an encapsulated housing of insulating material, a conducting plate, an insulating wafer and a plurality of spaced electrodes contained within said encapsulated housing, said insulating wafer separating said electrodes from said plate and having a plurality of openings generally aligned with said electrodes, and terminal means for electrically connecting said electrodes to said current conducting leads of said tube receiving unit.

2. A tube socket assembly as defined in claim 1, wherein each of said spaced electrodes includes a spherical portion extending into one of said openings in said insulating wafers and wherein said conducting plate includes a plurality of spherical portions corresponding in number to said spaced electrodes and disposed to extend into said openings a distance to define a spark gap with the associated spherical portion of said spaced electrodes.

3. A tube socket assembly as defined in claim 1, wherein each of electrodes has a lead portion in alignment with said openings in said insulating wafer and a terminal portion extending outwardly of said encapsulated housing, the outer end of said terminal portions being electrically connected with said current conducting leads of said tube receiving unit.

4. A tube socket assembly as defined in claim 1, wherein said encapsulated housing is evacuated.

5. A tube socket assembly as defined in claim 1, wherein said encapsulated housing comprises a pair of insulating disks covering the exposed side of said electrodes and said conducting plate and sealed onto said insulating wafer.

6. A tube socket assembly as defined in claim 1, further comprising a terminal board having a plurality of apertures therethrough spaced to receive said current conducting leads of said tube receiving unit.

7. A tube socket assembly as defined in claim 6, further comprising an edge connecting having a plurality of male terminal pins and mounted on one margin of said terminal board, and means for electrically connecting said current conducting leads to said male terminal pins.

8. A tube socket assembly comprising a tube receiving unit and a spark gap unit; said tube receiving unit comprising a socket body formed of insulating material in the shape of base portion and an upstanding circular neck portion, said neck portion having a plurality of terminal pin-receiving openings arranged in a circular arc and extending downwardly from its upper surface, a tubular current conducting contact seated in each of said terminal pin-receiving openings, and a current conducting lead extending from each of said tubular contacts through said base portion and having a terminal portion extending away from said base portion; said spark gap unit comprising a ring-shaped encapsulated housing of insulated material encircling said neck portion and resting on the upper planar surface of said base portion, a collecting ring, a ring-shaped insulating wafer and a plurality of spaced electrodes contained within said encapsulated housing, said insulating wafer separating said electrodes from said collecting ring and having a plurality of openings generally aligned with said electrodes, and terminal means for electrically connecting said electrodes to said current conducting leads of said tube receiving unit.

9. A tube socket assembly as defined in claim 8, wherein each of said spaced electrodes includes a spherical portion extending into one of said openings in said insulating wafers and wherein said conducting plate includes a plurality of spherical portions corresponding in number to said spaced electrodes and disposed to extend into said openings a distance to define a spark gap with the associated spherical portion of said spaced electrodes.

10. A tube socket assembly as defined in claim 8, wherein each of electrodes have a lead portion in alignment with said openings in said insulating wafer and a terminal portion extending outwardly of said encapsulated housing, the outer end of said terminal portions being electrically connected with said current conducting leads of said tube receiving unit.

11. A tube socket assembly as defined in claim 8, wherein said encapsulated housing is evacuated.

12. A tube socket assembly as defined in claim 8, wherein said encapsulated housing comprises a pair of ring-shaped insulating disks covering the exposed side of said electrodes and said collecting ring and sealed onto said insulating wafer.

13. A tube socket assembly as defined in claim 1, further comprising a terminal board having a plurality of apertures therethrough spaced to receive said current conducting leads of said tube receiving unit.

14. A tube socket assembly as defined in claim 13, further comprising an edge connecting having a plurality of male terminal pins and mounted on one margin of said terminal board, and means for electrically connecting said current conducting leads to said male terminal pins.

15. A spark gap unit adapted for use in a tube socket assembly comprising an encapsulated housing of insulating material, a conducting plate, an insulating wafer and a plurality of spaced electrodes contained within said encapsulated housing, said insulating wafer separating said electrodes from said plate and having a plurality of openings generally aligned with said electrodes, terminal means extending from said plate outwardly of said encapsulated housing, and said electrodes having terminal portions extending outwardly of said encapsulated housing.

16. A spark gap unit as defined in claim 15, wherein is said encapsulated housing comprises a pair of insulating disks covering the exposed side of said electrodes and said conducting plate and sealed on said insulating wafer leaving said terminal portions of said electrodes and said terminal means uninsulated.

17. A spark gap unit as defined in claim 15, wherein each of said spaced electrodes includes a spherical portion extending into one of said openings in said insulating wafers and wherein said conducting plate includes a plurality of spherical portions corresponding in number to said spaced electrodes and disposed to extend into said openings a distance to define a spark gap with the associated spherical portion of said spaced electrodes.

18. A spark gap unit as defined in claim 15, wherein said encapsulated housing is evacuated.