US3571952A

US3571952A - Electrode holder for use with an intermittently operated spark gap

Info

Publication number: US3571952A
Authority: US
Inventors: Siegfried Schmidt; Bernd Ehlers
Original assignee: US Philips Corp
Current assignee: US Philips Corp
Priority date: 1966-10-22
Filing date: 1967-10-09
Publication date: 1971-03-23
Anticipated expiration: 1988-03-23
Also published as: BE705459A; NL6714052A; DE1513017A1

Abstract

An electrode holder arrangement with two spaced electrodes defining a spark gap therebetween and provided with an insulator means within the spark gap for defining a spark waveline path. The electrodes are spring urged toward the insulator means and each other and are also mounted for rotation about the longitudinal axis.

Description

United States Patent Inventors Appl. No.

Filed Patented Assignee Priority ELECTRODE HOLDER FOR USE WITH AN INTERMI'I'I'ENTLY OPERATED SPARK GAP 6 Claims, 6 Drawing Figs. US. Cl

313/149, 219/69, 219/384, Int. Cl H0lj 7/44, H01 j 13/46 FieldofSearch ..2l9/ 9(U) Siegfried Schmidt Hamburg;

Bernd Ehlers, Tomesch, Germany 673,774

Oct. 9, l 967 Mar. 23, 197 1 US. Phillips Corporation New York, N.Y.

Oct. 22, 1966 Germany [56] References Cited UNITED STATES PATENTS 2,730,602 l/1956 Porterfield 219/69 2,758,238 8/1956 Todd 313/149 3,351,740 11/1967 Heuer.. 219/384 3,042,789 7/1962 Niederhoff 219/69 FOREIGN PATENTS 270,140 5/1966 Australia 219/384 Primary Examiner-John W. I-Iuckert Assistant Examiner-Barry Estrin Attorney-Frank R. Trifari ABSTRACT: An electrode holder arrangement with two spaced electrodes defining a spark gap therebetween and provided with an insulator means within the spark gap for defining a spark waveline path. The electrodes are spring urged toward the insulator means and each other and are also mounted for rotation about the longitudinal axis.

PATENTED HAR23 I97!

sum

1 or 3 LII.

'2 S IEGFRIED SC BERND EHLERS AGENT PATENTEDHAR23|97| 8.571.952

SHEET 2 OF 3 INVENTOR. SIEG FRIED SCHMIDT BERND EHLERS BY mEmwmzsmn 3.571.952

SHEET 3 OF 3 INVENT SIEGFRIED SC HM BERND EHLERS AGENT ELECTRODE HOLDER FOR USE WllTfli AN HNTERWTTENTLY OPERATED SPARK GAP The invention relates to a spark printing, punching, or similar apparatus, more particularly to a device comprising at least one electric spark gap between one pair of spaced electrodes, wherein at least one of which electrodes of the pair is displaceable in a direction toward the other electrode. Since the electrodes at the spark gap are subject to wear by loss of material at the origin of the sparks, compensation for such wear is usually accomplished by causing at least one of the electrodes to be displaced in the direction towards the other in accordance with the material losses.

If the wear per unit time is known and if it is uniform, a clockwork may be employed for the required readjustment of one electrode. Such arrangements are known for carbon points. With intermittently operated spark gap, for example, for producing shock waves in spark printers and spark punchers an electrode feed proportional with time cannot be used. The feed has to be equal to the material loss. This might be achieved by pressing the side of the electrode subject to wear against a stop like the brushes of commutators and slip rings. In the latter case the stop is formed by the commutator or the slip ring respectively. With spark tracks, however, the side of the electrodes subjected to wear is adjacent a gas so that it cannot be pressed against a stop without the need for further means. This invention avoids the above problem.

According to the invention, the device is characterized in that a displaceable electrode is formed by a body adapted to be rotated about an axis said body being rotated symmetrically with respect to said axis. A part of the surface of the body intended for the formation of the sparks is continually urged toward the other electrode and will constantly engage a stationary insulator body. The location of the spark originating from the electrode is determined by that part of said sparking surface which is clear of the insulator body.

Preferably a displaceable electrode is formed by a hollow tube having a head face which forms the surface intended for the generation of sparks and the tube is spring urged against the insulator body, with part of the head face projecting beyond a surface of the insulator body.

Another possibility consists in employing a rotatable disc as a displaceable electrode, the peripheral surface of which forms the surface intended for the formation of the sparks. A further possibility, which is particularly suitable for devices comprising a plurality of closely adjacent spark gaps with parallel-connected main electrodes consists in using a cylindrical electrode the peripheral surface of which forms the surface intended for the formation of the sparks, which surface is in contact with the insulator body.

A few embodiments of the invention will be described hereinafter with reference to the drawings, in which:

FiG. ii is a diagrammatic sectional view of a sliding spark track comprising tubular electrodes,

H08. 2 and 3 show electrode arrangements,

FIG. a shows diagrammatically an arrangement comprising disc-shaped electrodes,

FIG. is diagrammatic sectional view of an arrangement comprising parallel cylindrical electrodes,

FIG. ti is a diagrammatic plan view of the arrangement of FIG. 5.

In the sliding spark track of FIG. I

tubular metal electrodes

3 and 4, for example consisting of tungsten are employed. The spark, indicated herein by a waveline i, jumps over along the surface of an insulator 2, serving at the same time as a stop, between the

electrodes

3 and 4 said electrodes for example consisting of ceramic material or aluminia. The

tubular electrodes

3 and 4 may be guided in plates 5 and 6 and are urged against the insulator 2 by means of springs 7 and 8 (spring 8 is not visible) and connecting

rods

9 and 10 so that the major portion of the head faces of the tube engages the sidewalls of the insulator 2 and the tubular electrodes 3 and extend beyond the side of the insulator 2 facing the spark l approximately by the wall thickness of the tube. The insulator 2 may have a third auxiliary electrode for igniting the spark, which is not illustrated.

The electrodes 3 and t are adapted to rotate about their axes. They are driven by means of gear wheels l3 and M, by means of axial notches secured to sleeves I1 and I2. The sleeves I I and R2 are connected with rods 9 and If) by

pins

19, 20, fixed in said sleeves.

Other pins

21 and 22 connect the rods 9 and It) with the

electrodes

3 and 4. The sleeves l I and 12 are journaled in plates 15 and I6 and axially fixed thereon by setting rings l7 and 18. The prime mover itself is not shown. it may provide a continuous rotation or a rotation proportional to the number of discharges. The rotation may be performed invariably in one direction or it may change after each revolution. In the first case the current is supplied through slip rings or through the guide in the plates 5 and 6, said plates then consisting of metal. In the second case a fixed electric connection may be established via flexible conductors.

In order to separate electrically the driving part from the electrodes the connecting rods 9 and T0 are made of an insu lating material, for example a ceramic material.

This disposition ensures that the different parts of the head faces of the

electrodes

3 and 4 are successively exposed to wearing off or cooperate with the insulator 2 for fixing the place of the electrode in axial direction. Thus even with u very great consumption and with a high number of discharges the distance of the electrodes remains substantially constant.

The arrangement is furthermore constructed so that the electrodes are shaped in an easily obtainable form and are readily exchangeable.

FIG. 2 shows the essential parts of an arrangement with a spark track for punching paper. The paper 23 to be punched engages by one side a punching matrix 24. The discharge space is located on the other side of the paper. The spark is again indicated by a waveline 30. The

electrodes

28 and 29, like the

electrodes

3 and 4 of FIG. 1, are formed by tubes which are adapted to be rotated and to be urged against the insulator 27. These electrodes are guided in

plates

25 and 26 so that the

axes

28 and 29 of the electrodes extend obliquely to the plane of the sparks. It is thus ensured that no structural parts hinder the disposition of the paper and of the matrix near the discharge area. Also in this case a third, stationary electrode, held in the insulator 27, may be provided for igniting the discharge.

The arrangements shown in FIGS. I and 2 are also suitable for use with closely adjacent spark tracks. If the main electrodes of these adjacent spark tracks are connected in parallel, for example in serial printers or punchers it is efficacious to have the main electrodes of a plurality of spark tracks formed by two tubular electrodes.

The arrangement shown in FIG. 3 is particularly suitable for producing free sparks in a gas (in contrast to sliding sparks along the surface of an insulator). Such sparks are particularly employed for illumination and switching purposes. In this case the axes of the tubular main electrodes 3i and 32 extend obliquely to the spark track 33, which is again indicated by a waveline.

The head face portions of the main electrodes 3i and 32 farther remote from each other form the stop surfaces of an insulator 34. The head face portions of the

main electrodes

31 and 32 lying more closely to each other are spaced apart from the surface of the insulator 3 3 by the choice of the tube diameter and by the oblique disposition by such a distance and are located so closely to each other that the electric breakdown is produced just at this place. The rotation and the push of the

electrodes

31 and 32 are indicated by arrows. The means required thereto are not shown. The tubular shape of the electrodes 3i and 32 provides at the same time a simple possibility of introducing gas, namely through the electrodes, into the discharge zone, as is required for example in blow spark tracks.

in the arrangement shown in FIG. 4 the main electrodes 35 and as are formed by rotatable discs, which are urged by

springs

37 and 3% against an insulator 39.

FIGS. 5 and a show diagrammatically a particularly simple embodiment of an arrangement according to the invention for a plurality of closely adjacent spark tracks with parallel-connected main electrodes, as employed in serial printers and punchers. FIG. 5 is a sectional view of this arrangement and FIG. 6 is a plan view of the spark tracks broken off on the right-hand side. The

main electrodes

41 and 42 are formed by metal tubes or cylindrical rods, the cores (43, 44) of the rods not being made of electrode material. The cores may be insulating shafts establishing the mechanical connection with the driving member 52, shown only diagrammatically. The wear and stop surface is the sheath surface of the cylindrical

main electrodes

41 and 42. The electrodes (41, 42) rotating about their axes are urged against the insulator 47 by two leaf springs (45, 46), which also serve for supplying the current. In order to avoid uneven consumption losses the electrodes are reciprocated approximately over the distance between the spark tracks in the axial direction. The electrode 41 is shown in the state shortly before the end of its lifetime and the electrode 42 is shown in the new state. The stationary

auxiliary electrodes

48, 49, 50 and 51, taken through the insulator 47, serve for igniting the sparks an determine again and again the place of discharge. The

wavelines

53, 54, 55 and 56 indicate the position of the discharges, only one of which can occur at a given instant in this arrangement.

In the sliding spark track arrangements according to the invention it is advantageous to apply one of the known measures against insulator wear. By using tape-shaped insulator portions the portions of the insulator surface exposed to wear may be continuously achieved or this surface may be wetted.

We claim:

I. An electrode holder arrangement for use with an intermittently operated spark gap comprising two spaced electrodes forming a spark gap therebetween, said electrodes being adapted for rotation about a symmetrical longitudinal axis, insulator means in said spark gap for defining a spark waveline path between the electrodes, means for urging at least one of the electrodes toward the other electrode and against the insulator means so as to displace the electrode and automatically compensate for its wear, said electrode comprising a hollow tube being positioned so that one portion of the end face of the tube is urged against the insulator means and a second portion of the en face projects clear of the insulator means so as to generate sparks across the gap.

2. An apparatus as claimed in claim I wherein the insulator means comprises an insulated body defining a recess for receiving the end face of the hollow tube electrode.

3. An apparatus as claimed in claim 2 wherein the two elec trodes are positioned with relation to the insulated body so that their longitudinal axis are at an angle to each other.

4. An apparatus as claimed in claim 3 wherein the insulated body has a guide surface extending from one electrode to the other electrode, which surface serves to guide the sparks sliding between the electrodes.

5. An electrode holder arrangement for use with an intermittently operated spark gap comprising two spaced electrodes forming a spark gap therebetween, said electrodes being adapted for rotation about a symmetrical longitudinal axis, insulator means in said spark gap for defining a spark waveline path between the electrodes. and biasing means for automatically displacing both of said electrodes toward each other and against the insulator means so as to substantially maintain a constant distance between said electrodes thereby compensating for their wear, said displaceable electrodes being in the form of a disc having a peripheral surface, said insulator means being a solid insulator, and wherein said biasing means comprises a spring mounted for engagement with said electrodes at their center so that said electrodes are displaced toward each other and urged against the solid insulator, the sparks being emitted from a portion of the said surface which is clear of the insulator means.

6. An electrode holder arrangement for use with an intermittently operated spark gap comprising two spaced electrodes forming a spark gap therebetween. said electrodes being adapted for rotationabout a symmetrical longitudinal axis, insulator means in said spark gap for defining a spark waveline path between the electrodes, and biasing means for automatically displacing both of said electrodes toward each other and against the insulator means so as to substantially maintain a constant distance between said electrodes thereby compensating for their wear, said electrodes being cylindrically shaped, said insulator means is a solid insulator, wherein said biasing means comprises a leaf spring attached to said solid insulator being in contact with the peripheral surfaces of said electrodes thereby displacing said electrodes toward each other and urged against the insulator, the sparks being emitted from a portion of the said surface which is clear of the insulator said leaf springs acting as supply conductors for the electrodes, and further comprising means for axially reciprocating said electrodes so as to avoid uneven consumption of the electrodes.

79 22 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,571,952 Dated March 23, 1971 Inventor) SIEGFRIED SCHMIDT ET AL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 3, line 41, before face" en" and after "gap" should be -an insulating connecting rod having should be end;

one en:

engaging the hollow tube electrode, a

ment of the electrode, and drive end of within connec' displaI means I rotating the sleeve and electrode-.

Signed and Sealed this 1mm day of September,

(SEAL) Attest:

EDWARD M.FLETCHER,JR. Attesting Officer ROBERT GOTTSCHALK Acting Commissioner of Paton

Claims

1. An electrode holder arrangement for use with an intermittently operated spark gap comprising two spaced electrodes forming a spark gap therebetween, said electrodes being adapted for rotation about a symmetrical longitudinal axis, insulator means in said spark gap for defining a spark waveline path between the electrodes, means for urging at least one of the electrodes toward the other electrode and against the insulator means so as to displace the electrode and automatically compensate for its wear, said electrode comprising a hollow tube being positioned so that one portion of the end face of the tube is urged against the insulator means and a second portion of the en face projects clear of the insulator means so as to generate sparks across the gap.

2. An apparatus as claimed in claim 1 wherein the insulator Means comprises an insulated body defining a recess for receiving the end face of the hollow tube electrode.

3. An apparatus as claimed in claim 2 wherein the two electrodes are positioned with relation to the insulated body so that their longitudinal axis are at an angle to each other.

5. An electrode holder arrangement for use with an intermittently operated spark gap comprising two spaced electrodes forming a spark gap therebetween, said electrodes being adapted for rotation about a symmetrical longitudinal axis, insulator means in said spark gap for defining a spark waveline path between the electrodes, and biasing means for automatically displacing both of said electrodes toward each other and against the insulator means so as to substantially maintain a constant distance between said electrodes thereby compensating for their wear, said displaceable electrodes being in the form of a disc having a peripheral surface, said insulator means being a solid insulator, and wherein said biasing means comprises a spring mounted for engagement with said electrodes at their center so that said electrodes are displaced toward each other and urged against the solid insulator, the sparks being emitted from a portion of the said surface which is clear of the insulator means.

6. An electrode holder arrangement for use with an intermittently operated spark gap comprising two spaced electrodes forming a spark gap therebetween, said electrodes being adapted for rotation about a symmetrical longitudinal axis, insulator means in said spark gap for defining a spark waveline path between the electrodes, and biasing means for automatically displacing both of said electrodes toward each other and against the insulator means so as to substantially maintain a constant distance between said electrodes thereby compensating for their wear, said electrodes being cylindrically shaped, said insulator means is a solid insulator, wherein said biasing means comprises a leaf spring attached to said solid insulator being in contact with the peripheral surfaces of said electrodes thereby displacing said electrodes toward each other and urged against the insulator, the sparks being emitted from a portion of the said surface which is clear of the insulator said leaf springs acting as supply conductors for the electrodes, and further comprising means for axially reciprocating said electrodes so as to avoid uneven consumption of the electrodes.