US2241240A - Starting switch for gaseous discharge devices - Google Patents

Description

May 6, 1941. c. CHIRELSTEIN STARTING SWITCH FOR GASEOUS DISCHARGE DEVICES Filed Aug. 1'7, 1940 5 5 LE 8 E E mm m m m w m2 M O P JX M 3 37?: H a L m 0 H 4 i r K J l WHU 1 5 2 i u i i! 7. 7 am yzw. u N mMm NWP Hm HK INVENTOR.

Patented May 6, 1941 STARTING SWITCH FOR GASE'OUS DISCHARGE DEVICES Charles Chirelstein, Newark, N. J.

Application August '17, 1940, Serial No. 352,986

constructions for starting gaseous discharge devices, such as luminous tubes, lamps and the like.

Special objects of the invention are to provide a switch which will be reliable in its operation and will continue effective even with extended use; which will not fuse the contacts together, even under overload conditions; which will operate quickly and which with all such advantages will be inexpensive and practical in every way.

The foregoing and other objects are attained in the present invention by the novel features, combinations and arrangements hereinafter described, illustrated in the accompanying drawing and broadly covered in the claims.

The drawing accompanying and forming part of the specification illustrates one of the present preferred commercial embodiments of the invention. Modifications and changes however may be made, as regards this particular illustration, all within the true intent and scope of the invention as hereinafter defined and claimed.

In the drawing, the single illustration is a broken part sectional view of one of the new switch constructions.

The structure illustrated is generally similar in mechanical details to that shown and described in copending patent application Ser. No. 342,213 filed June 25, 1940.

In general, the switch construction referred to consists of a looped bimetallic switch contact I, and a cooperating contact 2, positioned to be engaged by the expanding arm of the first contact, these being sealed within a glass envelope 3, or

like container, supported Within a metallic housing or so-called can 4.

The wires or rods 5, 6, which carry and partially form the switch contacts are indicated as extended outside the envelope and as soldered or otherwise secured to the buttons 1, 8, which, at the outside of the can, are fashioned to form the terminals 9, 10, of the switch unit.

The can is shown as provided with an insulating lining II, and with a closure I2, of insulating material, which is held in place by the inturned tangs l3, and which forms an insulating base for the terminals.

To prevent sticking or fusing of the switch con tacts, these are made of unlike metals.

In a present preferred construction, the relatively fixed switch contact 2, is made of nickel and the low expansion strip or side 14 of the bimetallic switch contact is an alloy of approximately 64% steel and 36% nickel. The high expansion strip I which is at the inside of the loop is at present an alloy of approximately iron, 22% nickel and 3% chromium. The steel-nickel alloy at the outer side of the bimetallic loop makes engagement with the nickel terminal 2, and this particular combination of steel-nickel alloy to nickel does not stick or fuse even under heavy continuous service.

For so-calied low voltage V) work, speedy switch closing action has been accomplished by enclosing the switch contacts in an atmosphere of approximately 84.5% to 89.3% eon, 15% to 10% helium and 5% to .'7% krypton. This particular combination of gases in approximately these proportions provides fast reliable switch closing operation. The pressure may be from about 4 to about 6 centimeters.

These switch units when entered in the sockets provided for them are usually surrounded and enclosed at the sides, so that they can not be reached for Withdrawal from the socket. In such case, usually only the end of the can is exposed. To overcome this difiiculty and make it possible to readily remove the switch unit from such socket, the present invention involves as a further novel feature. the provision of the upper or closed end of the can with an outwardly expanded rim l6, which may be knurled or roughened as indicated, to enable the fingers to readily grip and hold this narrow expanded rim portion both for rotating and for longitudinally withdrawing the can, and hence the unit from the socket.

Another feature of the present invention i the use of a getter composed of from about 25 to 30% barium and the balance of magnesium. With this special getter the starting voltage necessary to produce ionization is reduced by about 5 to 8 volts. In addition, the normal life of the starter is increased, usually by more than 100%.

Results are further improved by arranging the getter to direct the getter flash downward, that is, toward the bimetallic switch element l4, l5, so as to actually coat this switch element with the magnesium-barium composition. This coating of the bimetallic element further reduces the ionization voltage and further increases the life of the tube.

This getter has been used in the manner described with low voltage tubes, that is, the gaseous tubes which operate the present types 15 and 20 watt fluorescent lamps operating on 90 to volts A. C. and D. C. current.

What is claimed is:

1. A starting switch for gaseous discharge devices, comprising a sealed envelope, relatively movable switch contacts sealed in said envelope and comprising unlike metals, a filling of a mixture of rare gases sealed in said envelope and including from about 8% to 89% neon, about 15 to 10% helium and about .5 to 37% krypton.

2. A starting switch for gaseous discharge devices, comprising a sealed envelope, relatively movable switch contacts sealed in said envelope and comprising unlike metals, 2. filling of a mixture of rare gases sealed in said envelope, one of said switch contacts being nickel and the other cooperating contact being a ferrous alloy containing nickel.

3. A starting switch for gaseous discharge devices, comprising a sealed envelope, relatively movable switch contacts sealed in said envelope and comprising unlike metals, a filling of a mixture of rare gases sealed in said envelope, said switch contacts including a fixed contact of nickel and a bimetallic contact having a low expansion strip of ferrous nickel alloy for engagementwith 5. A starting switch for gaseous discharge devices, comprising a sealed envelope, relatively movable switch contacts sealed in said envelope, at filling of a mixture of rare gases sealed in said envelope and including from about 84 to 89% neon, about 15 to 10% helium and about .5 to 37% krypton.

6. A starting switch for gaseous discharge devices, comprising a sealed envelope, relatively movable switch contacts sealed in said envelope and including a movable bi-metallic switch element, a filling of a mixture of rare gases sealed in said envelope, including from about 84 to 89% neon, about 15 to 10% helium and about .5 to .7% krypton and a barium-magnesium composition sealed in said envelope with said neon, helium and krypton and including a coating of barium-magnesium on said movable bi-metallic switch element.

'7. A starting switch for gaseous discharge devices, comprising in combination, a sealed envelope, switch contacts sealed in said envelope and including a movable bi-metallic switch element, a rare gas atmosphere sealed in said envelope and barium-magnesium sealed in said envelope and including a coating of barium-magnesium on said movable bi-metallic switch element.

CHARLES CHIRELSTEIN.

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