US3240980A - Spark gap socket - Google Patents

Description

March 15, 1966 w. 0. SCHUSTER SPARK GAP SOCKET 2 Sheets-Sheet l INVENTOR W/W/am .D. Schuszer BY W a AT ORNE Filed Jan. 5. 1961 March 15, 1966 w. D. SCHUSTER SPARK GAP SOCKET 2 Sheets-Sheet 2 Filed Jan. 5. 1961 INVENTOR IV/Ma/n D. Sam/star BY AT RN E Y United States Patent Ofiice 3,240,980 Patented Mar. 15, 1966 3,240,980 SPARK GA? SOCKET William I). Sehuster, Oakfield, N.Y., assignor to Sylvania Electric Products Inc., a corporation of Delaware Filed Jan. 3, 1961, Ser. No. 80,207 6 Claims. (Cl. 313-318) This invention relates generally to spark discharge devices and more specifically to cathode ray tube pin connected devices for external spark gap discharge of electrical energy passed by internal electrode arc-over.

Cathode ray tube gun designs have been moved toward closer and closer spacing tolerances by the demands of circuits with which the tubes must operate. The resulting electrode spacing, though completely satisfactory in gun structures having clean cut electrodes, free of burrs or sharp edges, results in a plague of arc-overs when the electrode parts are either dirty or not completely free of sharp edges or small needle points. Since even the best of inspection systems is bound to pass some gun parts which have not been cleanly cut or made burr free, many of the new cathode ray tubes have a tendency toward internal arc-over at least during the first several months of use. Though this internal arcing usually burns off the undesirable are points on the electrodes and does no harm inside the tube, sometimes connected external components are damaged. Even when external components are not injured, the undesirable snapping and crackling noise generated by the resulting external arc-overs is not exactly comforting to the average new customer. Often these noises form the basis of a request for repair service.

Thus it is an object of this invention to eliminate the majority of crackling, snapping and other external circuit noises arising from internal cathode ray tube electrode current arc-overs.

It is a further object of this invention to minimize undesirable high potential build-up between circuit com.- ponents external the cathode ray tube and ground.

Briefly considering one aspect of the invention, I provide a cathode ray tube socket including a conductor mounted adjacent and spaced from the tube pin receiving contacts. High voltage insulation is provided between this conductor and the socket contact, except where spark gap discharge is desired, and at these points the insulation is apcrtured.

For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the accompanying drawings in which:

FIG. 1 is an exploded view of a cathode ray tube socket embodiment; and

FIG. 2 is a plan view of a second cathode ray tube socket embodiment; and

FIG. 3 is a cross section view of the socket of FIG. 2; and

FIG. 4 is a plan view of a third cathode ray tube socket embodiment; and

FIG. 5 is a cross section view of the socket of FIG. 4; and

FIG. 6 is an end view of a cathode ray tube base embodiment.

Referring to FIG. 1 there is shown the base end of a cathode ray tube 11 including a base key 13 and tube pins 15, 17, 18, 19 and 20 which are connected to electrodes internal the cathode ray tube, not shown.

Tube socket 27, when in position on the tube pins, interconnects them with the associated circuit leads 29 through 34 by way of pin receiving contacts 35 through 40. Insulating disc 41 is apertured at 43 and 45 to receive mounting screws 47, 49 which are threaded to be received in threaded socket body apertures 51 and 53.

' electrode is involved in the internal arc-over.

Insulating disc 41 is also apertured at 55, 57, 59 and 61 to provide spark discharge paths as will be brought out more fully hereinafter. Washer or disc 63 which com prises an insulating layer 65 and a conducting layer 67 is formed to provide scallops 69, each of which, upon assembly in socket 27, is associated and positioned adjacent one of the socket lead-in wires 29 through 34. Washer 63 is also apertured at 71 and 73 to receive mounting screws 47 and 49. After leads 29 through 34 have been soldered into place on the solder lugs of pin receiving contacts 35 through 40, insulating disc 41 and scalloped washer 63 are mounted in place on socket body 27 with mounting screws 47 and 49.

The resulting structure then functions as a pre-set voltage, spark discharge gap to ground for the various electrodes internal of cathode ray tube 11. For example, in one particular type of cathode ray tube, pin 15 is internally connected to the focus electrode. Pin 16 is connected to G while pins 17 and 20 are connected to the G and cathode electrodes, respectively. Pins 18 and 19 are connected internally to the cathode heater element. In this particular tube, arcing may occur between the second anode portion of the gun, which receives its high voltage through the internal aquadag tube coating, and either the focus electrode or the G electrode. Without spark gap protection of the external circuit, each time an internal arc-over occurred there was a discharge through the external lead pin connected to the electrode, down to the chassis through a connected lead with a resultant arc-over to ground, either around or through components designed to break down at voltages much lower than the second anode potential. With the socket shown in FIG. 1 after assembly, assuming that heater lead 32 is grounded, little if any damage or noise will result regardless of which For example, if there is an internal arc-over between the cathode ray tube second anode electrode and the focus electrode, then the potential of tube pin 15 is raised toward the second anode potential, which is usually in the range of 15,000 to 20,000 volts. Much before the potential on tube pin 15 can reach the second anode potential value an are forms through insulation disc aperture 55 to metal film 67 and back through insulation disc aperture 61 to the grounded heater lead 32. The voltage at which areover occurs through insulation disc 41 depends primarily upon its thickness and to some extent on the size of the apertures used since edge scallops on washer 62 make certain that no arcing occurs around disc 41 at the leadins. Thus by selecting the area of metal film 67 exposed through the apertures in insulation disc 41, a substantially fixed spark-over voltage may be selected from a reasonable range of possible voltages, all of which are considerably less than the usual second anode voltage value.

For example, a pre-set arc-over voltage range between approximately 750 and 1500 volts has proven suitable for at least one television receiver circuit. This voltage level is low enough to minimize arc-over damage to connected external components and yet high enough to avoid any tendency to arc-over under normal tube electrode signal or bias conditions. The selected arc-over voltage may vary from one receiver circuit to another; however, in all cases this preset voltage should be a fraction of the second anode voltage.

Since the amount of noise generated by an are discharged in air is usually directly related to the length of the discharge gap, and since the discharge voltage level is also directly related to the arc gap or distance, by setting a short arc-over distance with a resultant low level areover voltage, much of the undesirable crackling and snapping is eliminated. In fact, in most cases are generated noise is barely audible.

It is to be noted that the discharge should be to ground and in some circuits a special ground lead to socket 27 may be necessary.

A second embodiment is shown in FIGS. 2 and 3 wherein the reference numerals are the same as used in FIG. 1 for similar parts. Thus in FIG. 2, a socket body 27 is formed to provide a central aperture 30 for receiving tube base key 13 and is also formed to provide apertures for receiving contacts 35 through 40. As can best be seen in FIG. 3 the tube pin receiving contacts 35 through 40 each include a solder lug, such as solder lug 82, which is bent substantially 90 radially outward from the pin receiving portion of the contact so as to extend the lugs over socket body annular groove 84. A circular shaped conductor or metal washer 86 which functions as did washer 63, shown in FIG. 1, is mounted in annular groove 84. Mounted between metal washer 86 and the various solder lugs, connected to contacts 35 through 40, is an apertured insulation disc 88 which functions as did insulation disc 41, shown in FIG. 1. Insulation disc 88 is apertured only beneath each solder lug where arc-over is desired. These apertures may be grooved slits 89 as shown in FIG. 2 or they may be circular, similar to those shown in insulation disc 41 of FIG. 1. The shape of the aperture, though of some importance, is not as important as its cross sectional area, in pre-setting the arc-over voltage. As can be seen, disc 88 and washer 86 are locked against rotation in annular groove 84 by indexing fingers 90 which may be formed as a portion of socket body 27.

It will be noted that metal washer 86 does not extend out radially for a distance sufficient to fill annular groove 84. The reason for allowing this small clearance is to minimize the chance of an arc forming around insulation disc 88 at points where no arcing is desired, rather than through the apertures in disc 88 where arcing should take place when necessary. The need for the additional clearance is similar to the need for edge scalloping on washer 63 of FIG. 1.

It is to be further noted that neither the insulation disc 41, in FIG. 1, nor insulation disc 88, in FIGS. 2 and 3, is apertured opposite socket contact 40. This is because socket 40 is connected in use to tube pin 20, which in turn is internally connected to the cathode electrode, not shown, of tube 11. From the viewpoint of cathode ray tube life, it is harmful to allow any major portion of the second anode potential to be impressed upon the cathode. Thus the cathode lead is not internally involved in external arc-overs and internal arc-overs to the cathode seldom occurs.

Another embodiment is shown in FIGS. 4 and wherein a metal washer 100 is mounted internal the position of the contact apertures of socket body 27 and external the central aperture 80. In this particular embodiment washer 100 is not to be a completely closed ring because of the size of central key way aperture 80. In other embodiments this ring could be completely closed or notched to receive the key notch 81. In still other embodiments the washer 80 may be mounted on external surface 101 of socket body 27. The high voltage insulation 102 placed upon the outer periphery of washer 100 may be attached to the washer by adhesive or by any other means. Also washer 100 may be attached by adhesive to socket body 27 in order to minimize possibility of rotation out of the correct position. Other means of holding washer 100 in place will occur to those skilled in the art. Insulation 102 is perforated to allow arc-over at the proper contact points as has been shown in and discussed in connection with disc 41 in FIG. 1 and disc 88 in FIG. 3.

In the socket embodiment of FIGS. 2 and 4 a protective cover should be provided which rests on ledge 103. The cover may be attached, in the embodiment of FIG. 2, either by adhesive or by providing a snapping notch in indexing fingers 90. The cover may be mounted in the embodiment of FIG. 4 through the use of screws received in threaded apertures 51 and 53.

The structure of FIG. 4 operates in the same manner as the embodiments of FIGS. 1 and 2. One advantage of the structure of FIGS. 4 and 5 is the small amount of material used over and above that used in the conventional portions of the socket.

Referring to FIG. 6 there is shown an end view of a tube base having pins 15 through 20 which is similar to the base of tube 11, as shown in FIG. 1. A key 13 is provided in the structure of FIG. 6, similar to the key shown in FIG. 1. Mounted on the base by adhesive or some other means is a metal washer coated on its outer periphery with high voltage insulating material 111. Again, insulating material 111 is apertured adjacent certain tube pins somewhat similar to that shown in FIGS. 1, 2 and 4. Assembly of a conventional socket to a cathode ray tube including the structure of FIG. 6 provides a pre-set arc-over device which will function somewhat the same as the devices shown in FIGS. 1, 2 and 4. The structure of FIG. 6 has an inherent disadvantage which is not present in the other embodiments. It requires an additional assembly step by the television received manufacturer while the structures of FIGS. 1, 2 and 4 may be machine assembled by the socket manufacturer at less cost.

The material selected for the socket body in FIGS. 1, 2 and 4 may be conventional. The material selected for the metal surface 67 of washer 6 3 as well as the metal washers 86 and 100, shown in FIGS. 3 and 4, respectively, may be made of copper or any other conducting material which will not pit or be damaged to any great degree by arcing. The high voltage insulating material such as the insulation disc 41 in FIG. 1, insulation disc 88 in FIG. 3 and insulation material 102 in FIG. 4 should be selected not only to provide sufficient insulation between the metal washer for those contacts where arcing is not desired but it also should be selected for minimum carbonizing, burning or tracking. That is, the insulation should not break down in the presence of an arc so as to form a conductive path over its surface. Flame retardant vinyl as well as Nylon, which is a thermoplastic, and Mylar have proven satisfactory. Other types of insulation will occur to those skilled in the art. The surface area of the metal washer is sufliciently small, in the embodiments shown herein, so that no capacitance problem arises in most circuits between the various output leads of the cathode ray tube.

While there has been shown and described what is at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein Without departing from the invention as defined by the appended claims.

Having thus described my invention, I claim:

1. In an electron tube connector the combination comprising a plurality of conduction means for establishing at least a portion of an electrical path between electron tube internal electrodes and external circuit leads, said plurality of conduction means being mounted in an electrical insulating medium in spaced array, a conductor mounted adjacent and spaced from at least a portion of said plurality of conduction means, and insulating material of substantially uniform thickness mounted between said conductor and each adjacent conduction means, said insulating material having apertures therethrough providing for spark discharge between said conductor and certain ones of said adjacent conduction means.

2. In an electron tube socket the combination comprising a plurality of electron tube pin receiving contacts supported in a socket body in spaced tube pin receiving array, said contacts each including a terminal lug portion suitable for attachment to a connecting circuit lead, whereby each contact held tube pin, each contact and the terminal lug attached portion of each connecting lead join i0 form a separate conduction path through said socket body, a conductor means mounted in spaced relationship with each of said separate conduction paths, and insulation means between said conductor and each of said conduction paths, said insulation means having apertures therein to provide certain conduction paths to form a spark discharge path.

3. A spark gap cathode ray tube socket comprising a ring of tube pin receiving contacts mounted in a socket body, said contacts each including a solder lug portion depending downwardly and bent radially outwardly from the remainder of the contact, an external lead connected to each solder lug, a metallic disc mounted over and adjacent said solder lugs, and an insulation disc mounted between the metallic disc and the said solder lugs, said insulation disc having apertures so constructed and arranged that a path is provided for spark discharge between certain of said solder lugs and said metallic disc.

4. A spark gap cathode ray tube socket comprising a ring of tube pin receiving contacts mounted in a socket body, said contacts each including a pin receiving portion depending downwardly and a terminal lug portion bent radially outwardly from the remainder of the contact, a metallic disc mounted over and adjacent said terminal lug portions, and an insulation disc mounted between the metallic disc and said terminal lug portions, said insulation disc having apertures formed between certain of said terminal lug portions and said metallic disc providing a spark gap at said apertures between the certain terminal lug portions and the metallic disc.

5. In an electron tube socket the combination comprising a plurality of electron tube pin receiving contacts mounted in spaced relationship in a socket body, an electrical conductor supported at a given distance from said contacts, and insulation means inserted between said contacts and said conductor, said insulation means having apertures of varying size between selected ones of said contacts and the associated portion of said conductor,

5 each of said apertures combining with the area of said selected contact and associated portion of said conductor exposed thereto providing a path for spark discharge.

6. In an electron tube socket the combination comprising a plurality of electron tube pin receiving contacts 10 mounted in annular spaced relationship in a socket body,

a substantially circular shaped electron conductor supported on said socket at a given distance from said contacts, and insulation means inserted between said contacts and said conductor, said insulation means having apertures of varying size between selected ones of said contacts and the associated portion of said conductor, each of said apertures combining with the area of said selected contact and associated portion of said conductor exposed thereto providing a path for spark discharge.

References Cited by the Examiner UNITED STATES PATENTS 2,653,267 9/ 1953 McIntosh 313-245 2,794,962 6/ 1957 Donato 339-128 2,850,714 9/1958 Pace 313-318 X 2,915,734 12/1959 Alden 339-143 2,963,617 12/1960 Gray 31520 3,078,195 2/1963 Tummers et a1. 317235 DAVID J. GALVIN, Primary Examiner.

RALPH G. NILSON, GEORGE N. WESTBY,

Examiners.

Claims (1)

1. IN AN ELECTRON TUBE CONNECTOR THE COMBINATION COMPRISING A PLURALITY OF CONDUCTION MEANS FOR ESTABLISHING AT LEAST A PORTION OF AN ELECTRICAL PATH BETWEEN ELECTRON TUBE INTERNAL ELECTRODES AND EXTERNAL CIRCUIT LEADS, SAID PLURALITY OF CONDUCTION MEANS BEING MOUNTED IN AN ELECTRICAL INSULATING MEDIUM IN SPACED ARRAY, A CONDUCTOR MOUNTED ADJACENT AND SPACED FROM AT LEAST A PORTION OF SAID PLURALITY OF CONDUCTION MEANS, AND INSULATING MATERIAL OF SUBSTANTIALLY UNIFORM THICKNESS MOUNTED BETWEEN SAID CONDUCTOR AND EACH ADJACENT CONDUCTION MEANS, SAID INSULATING MATERIAL HAVING APERTURES THERETHROUGH PROVIDING FOR SPARK DISCHARGE BETWEEN SAID CONDUCTOR AND CERTAIN ONES OF SAID ADJACENT CONDUCTION MEANS.

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