US2232200A - High tension switch - Google Patents

Description

1941- E. F. BALDWIN BIGH TENSION SWITCH Filed March 22, 1937 INVENTOR.

BY 55% 7 ATTORNEYS.

Patented Feb. 18, 1941 UNITED v STATES PATENT OFFICE 5 Claims.

My invention relates to a high tension switch, and more particularly to a switch operating in the secondary of a transformer in such a manner that neither the primary nor secondary current is completely interrupted.

Among the objects of my invention are:

To provide a. sparkless high tension switch; to provide a high tension switch adapted for use in progressively illuminating luminous tubing; to provide a means and method'of switching high tension current from the secondary of a transformer; and to provide a simple, efllcient means and method for operating running signs utilizing luminous tubing.

My invention possesses numerous other objects and features of advantage, some of which, together with the foregoing, will be set forth in the following description of specific apparatus embodying and utilizing my novel method. It is therefore to be understood that my method is applicable to other apparatus, and that I do not limit myself, in any way, to the apparatus of the present application, as I may adopt various other apparatus embodiments, utilizing the .method, within the scope of the appended claims.

Luminous tubing embodying the rare gases, such as neon, helium, and the argon mercury combinations, are customarilyenergized by high voltage alternating current supplied by step-up transformers operating on the usual 110 or 220 volt line current. Consequently, if serial illumination of a length of luminous tubing is desired, secondary switching would be desirable providing sparking at contacts could be avoided, and providing current or voltage surges could be eliminated.

Broadly, my invention comprises as to method, serially energizing luminous tubing by progressively switching a high voltage current from a transformer secondary on to increasing lengths of tubing without opening either the primary or secondary transformer circuits. At the same time in the illumination cycle when the luminous tube is darkened in order that repeats may take place, I prefer either to cut down the input to the primary transformer to the point where the voltage of the secondary just will not illuminate the device, or to short circuit the secondary through a resistance sufficient to reduce the voltage applied to the tube below the striking voltage. In both cases surges are greatly reduced in magnitude and substantially sparkless operation is obtained due to the fact that the supply cir cuits are never completely broken.

I have also found that, when luminous tubing is serially energized by the use of multiple electrodes suitably spaced, inasmuch as these electrodes are only utilized for an extremely short period of time they may be much smaller in area than the main electrodes of the device, thus greatly decreasing the cost of building such tubes.

In the drawing:

The figure is a diagram illustrating one preferred form of my invention together with operational circuits.

My invention maybe best understood by direct reference to the drawing, and the Figure 1 a contact disc I is provided with a plurality of contacts 2 arranged in rows and extending toward the center of the disc. around the disc, and the number of contacts in each row, will depend upon the number of electrodes to be serially energized in a luminous tube 3. The arrangement of these contacts will be described later.

The luminous tube isprovided with a terminal electrode 4 and a plurality of intermediate electrodes 5, the latter being spaced along the tube at distances and at locations based on the judgment of the designer to get the best effect desired in what is commonly known as a running sign, where lengths of tubing, increasing by definite increments throughout the sign, are progressively illuminated.

In the particular embodiment shown in Figure l, the terminal electrode 4 is directly connected to the end of secondary 6 of a high voltage transformer, energized by a primary I from A. C. mains 8. A rotating contact arm 9 is driven by a motor l0, supplied through motor circuit H under the control of a motor switch I2. The contact disc I is supplied with a pair of primary slip rings l4 concentrically positionedaround the center of disc I, and a single secondary slip ring I5 is likewise concentrically positioned with respect to the primary rings.

The contact arm 9 is either directly connected to motor Ill or connected through suitable reduction gearing, preferably the latter. Contact arm 9 is provided with two primary brushes l1 and I8, these two brushes being connected together on the contact arm. The contact arm is also provided with a secondary brush I9 and an elongated contact brush 20, the latter being connected to secondary brush I!) on the arm.

The primary slip rings M are connected in series with the transformer primary 8 by slip ring circuit 2| under the control of slip ring switch 22, and the secondary slip ring [5 is connected to the other end of secondary 6 through The number of contacts,

wire 14. I prefer to mount the contacts 2 on the disc alongalineextendingtowardthecenter oi the disc which is at a slight angle, preferably about 15 degreeaiothelineofthecontactbrush 20, which is long enough radially to cover the lengthof the contact rows; and I have shown the contacts 2 in rows which are tangent approximatelytothe circledescribedbytheinner primary slip ring, whereas the contact brush 2. is along a direct radial line.

Inasmuch as the main consideration is to obtain an overlapping connection of the contact brush with contacts Litis obvious that the rows of contacts may be along a radial line and the angle of the contact brush 2| maybe changedjo allow two contacts in a row to be simultaneously engaged. It is important that the next following contact shall be energised before connection to the one immediately preceding is broken. Thus, in connecting up the contacts on the disc to the tube the innermost contact in the first row is connected. to the first auxiliary'electrode, the second contact in the same row is connected to the second auxiliary electrode, and so on until the outermost contact in the row is reached, and then the next in order will be the innermost contact of the next row. The angularity oi the contact rows and the brush is such that at all times the brush operates so that the secondary current is never broken. I

As the contact arm 9 swings around the contact disc 1 the time will come when all of the contacts have been serially energized and the sign therefore will be entirely illuminated. It

is then necessary to darken the sign and start over again at the and ordinarily the primary current is broken in order to accomplish this darkening of the sign. I do not desire, however, to break the primary current, but rather merely to reduce it so that the secondary voltage is reduced to a point where the gas in the tube is not broken down and ionized. I therefore pro-.

vide in one of the primary slip rings an insulated segment 25 which is connected back to the remainder of the segment through a primary resistor 26. Thus, when the primary brush I8 is on this segment primary currentis reduced, secondary voltage is likewise reduced, and the sign does not light. As the arm 8 continues rotation the brush l8 passes off from the insulated segment and full power is again supplied to the the primary circuit is reduced while the tube is darkened.

I should also like to point out, in constructing luminous tubes utilising illumination energizing auxiliary electrodes as shown, that it is neither necessary nor desirable for the auxiliary electrodesitobeoianygreat size. Eachauxiliary electrode is utilimd to carry the current only for averyshortlengthoftime,andonlyaftera relatively large interval of time. They may, therefore, be extremely small and may consist of smallwires sealed into the tube at the desired intervals. No great precaution is n inasmuch as even with'extremely small areas their life is normally far beyond the life of the larger terminal electrodes whichmust stand the full energization for extended lengths of time.

While I have shown a specific apparatus embodiment of my invention, it is obvious that apparatus equivalents embodying my novel method will be apparent to those-skilled in the art, and that such apparatus shall be deemed as falling within the scope of the appended claims.

I claim: I

1. A high tension switch comprising a base of insulating material, aplurality of spaced isolated contacts describing a portion of a circular band on said base, each contact having a lead extending therefrom for connection externally of said switch, a switch arm rotatable from the center of said circle over said contacts in order, a contact brush on said arm longer than the distance between said successive contacts whereby two contacts are always touching said brush during passage thereof over said contacts, a continuous uninterrupted secondary slip ring on said base, a secondary slip ring brush carried by said arm and connected to said contact brush, a pair of primary slip rings, primary slip ring brushes mounted on said arm and connected together, one of said slip rings including an insulated segment, and a resistance connecting said insulated segment to the remainder of the slip ring.

2. Apparatus in accordance with claim 1, wherein the spaced contacts are arranged in rows tangential to a circle smaller than the circular band described by said contacts and coaxial therewith and wherein the contact brush establishes simultaneous'contact with adjacent contacts in each of such rows during movement of the switch arm.

3. Apparatus in accordance with claim 1,

wherein the recited insulated segment extends 7 only over an arc corresponding to that portion of the circular band not occupied by said spaced contacts.

4. Apparatus in accordance with claim 1, wherein the spaced contacts are arranged in rows tangential to a circle mailer than the circular.

5. Apparatus in accordance with claim 1,

wherein the spaced contacts are arranged in rows tangential to a circle smaller than the circular band described by said contacts and coaxial therewith, and wherein the contact brush extends radially on said arm.

EUGENE F. BALDWIN.

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