US2076162A - Electric switch - Google Patents

Description

April 6, 1937. J. P. RUTH 2,076,162

ELECTRIC SWITCH Filed Nov. 13, 1935 INVENTOR Joh P Ruth ATTORNEY Patented Apr. 6, 1937 ELECTRIC SWITCH John P. Ruth, New York,

N. Y., assigner to General Electric Vapor Lamp Company, Hoboken, N. J., a corporation of New Jersey Application November 13, 1935, Serial No. 49,625

4 Claims.

The present invention relates to electric circuit makers and breakers, and particularly to those operating in a vacuum or other conditioned atmosphere.

A particular object of the invention is to pro- Another object of the invention is to provide a switch which is easily assembled with a predetermined relation between the operating parts.

Still other objects and advantages of the invention will appear from the following detailed specification or from an inspection of the Iaccompanying drawing.

The invention consists in the new and novel device hereinafter set forth and claimed.

Switches in which the circuit is made andP broken between solid contacts in a vacuum,

ticularly in response to a'magnetic field, are of especial value in many electrical circuits. For

example, such a switch has been found to be unusually effective as a so-called shifter to provide the surge in starting the well known Cooper-Hewitt mercury vapor arc lamps.

The switch disclosed by Warren R. Walker in his Patent 1,984,505, granted December 18, 1934, has been used very successfully for this purpose, and has already goneinto extensive use.

switch, however,

This type of requires considerable glass working skill in the assembly thereof.

I have now discovered that the manufacture of L, this type of switch can be greatly simplified and the cost thereof appreciably reduced by a novel construction of myinventiom At the same time this novel structure inherently results in the certain and dependable operation of the switch and eliminates the possibility of failure thereof due to faulty technique in the manufacture of the switch.

According to my invention the armature and the contacts of my novel switch are assembled ment and spacing into the enclosin freedom of movement o in a. predetermined relation such that their alignls rendered independent of the by which they are sealed g envelope. Furthermore the of the armature is so con trolled that the diameter of the enclosing envelope has no effect thereon, and this armature,

together with its associated circuit closing member, is positively part of the devi under a close and precluded from touching any ce whose dimensions are not positive control. Thus the possibility of the circuit closing member being jammed or stuck in the open circuit position is positively precluded under all conditions. Like wise my novel structure results in. the contact surfaces being far removed from all welds, where by it is easy to obtain a clean, undistorted contact surface of low resistance. As a result of these novel features my novel switch is readily assembled without the use of skilled labor and with the assurance that every switch will be perfect and dependable in operation throughout a long useful life.

For the purpose of illustrating my invention l have shown a preferred embodiment; thereof in the accompanying drawing, in which Fig. 1 is an elevational View, in part section of a switch which is especially designed for use as a shifter, and

Figs. 2 and 3 are switch of Fig. l, taken on the lines respectively.

As shown in this drawing my novel switch has a tubular sealed envelope I having an inlead 2 of tungsten or other suitable metal sealed axially into each end thereof through a reentrant seal 3. At a point near said seals a strip of molybdenum 4 is welded to the upper side of each of the inleads 2, preferably with the aid of an interposed strip of nickel 5, with the free end of the molybdenum strip extending toward the inner end of said ino lead and the free end of the nickel strip extending toward the seal. A cylindrical insulator 6 of porcelain or the like is positioned on each of the inleads 2 with one end close to the seal 3. Each of said insulators has a substantially triangular opening therein which closely fits the inlead 2 and the attached molybdenum strip 4, whereby rotation of said insulator on said inlead is preeluded. The end of the molybdenum strips 4 are bent upwardly against said insulators to retain them in position, and to serve as auxiliary ccntacts. Each insulator 6 likewise has a pair of recesses 8 therein at a point below the inleads 2 into which are fitted a pair of wires 9 of a suitable non-niagnetc metal which positively space and align the ends of the switch, A Ushaped member i0 of hon-magnetic material is supported by the wires 9, with the vertical ends of said member extending past, but out of Contact with, the inleads 2. In practice the wires 9 and this member I0 are both made of iron alloyed with 18% nickel and 8% chromium, this being non-magnetic in the annealed state. A vertical slot li from which all burrs have been removed is provided in each end of this member opposite cross-sectional views of the Z--2 and 3--3, 20

the ends of the inleads Il, and a tungsten wire I2 which serves to bridge the circuit between these inleads extends through said slots. At rest said wire lies upon said inleads, but the slots allow vertical movement of said wire away therefrom to open the circuit. A tubular armature I3 of steel or the like is loosely mounted on the wire I2 between the legs of the U-shaped member Ill and serves to actuate the wire I2 to an open circuit position when attracted by anexternal magnet suitably located above the envelope I. The ends of this tubular armature are preferably slightly rounded, as by ball milling, in order to insure freedom of movement thereof. A getter pellet I4 containing magnesium or the like is welded to one of the nickel strips 5 at a point adjacent to a seal The manufacture of this switch is extremely simple and requires neither skilled glass working nor any special selection of glass tubing for the envelope, due to the novel construction employed. Thus nrst of all the tungsten inleads 2 have a nare sealed thereto as at 3. The nat nickel and molybdenum strips Il and 5 are then welded thereto, and the getter pellet IH attached to one of the nickel strips 5. An insulator 6 is then slid onto each inlead 2, and locked in a fixed position thereon by bending the end of the molybdenum strip fl upwardly against said insulator. It will be noted that the point of weld on each inlead is within the insulator 6, and is thus remote from the contact making position of said inlead, the latter being thus kept clean and undistorted during this assembly process. A pair of wires 9 are then slipped through suitable Slots in the U- shaped member I@ and welded in place. The wire I2 is then slipped into position through the slots It and the armature I3, the latter being thereby locked in position. The wires 9 are then slid into position within the recesses 8 in the insulators 6 of the previously assembled parts, where they are held with sufficient friction to provide a readily handled unit in which all the parts are held in a predetermined relation and. alignment. The flares are then sealed'into a suitable' tubular envelope I, after which the device is evacuated and sealed oir in a conventional manner. In some cases, where a less abrupt opening of the circuit is desired, the device may of course be filled with any suitable inert gas, such as hydrogen at any desired pressure.

In the operation of this switch the armature I 3 is attracted upwardly by any suitable magnetic field, such as that produced by the electromagnet schematically represented by dotted lines in Fig. 1.v Said armature thereupon strikes a hammer blow upon the wire I2, causing the latter to move upwardly away from the inleads 2 to open the circuit. In practice this hammer blow is obtained through making the wire I2 of 45 mil tungsten where the bore of the armature I3 has a diameter of mils, whereby said armature travels an appreciable distance beforeit engages said wire. This of course tends to separate any partially fused contacts. In addition this construction allows the wire I2 to rotate about any point of fusion, which is always limited to one end of said wire at any one time, and as a result of both these factors it has been found that the circuit through this novel switch is opened with certainty under all conditions. In its open circuit position the wire I2 is held against the top of the slots II. Upon removal of the magnetic attraction the armature I3 drops, allowing the wire I2 to fall back into a circuit closing position under the guidance of said slots I I and the smooth upturned ends of the molybdenum strips 4. In this connection it may be noted that these strips 4 have sufficient area that the Wire I2 can never pass over the edge thereof in any position permitted by the slots II. The circuit is thereupon ordinarily closed by the wire I2 coming to rest on the inleads 2, although if the axis of the switch is at an angle to the horizontal one end of the wire I2 may rest against a molybdenum strip 4 while the other end rests upon the inlead 2. Either mode of operation is, of course, satisfactory, it being obvious that the circuit is closed with certainty in either case.

In addition to the decreased cost of manufacture of my novel' switch, which largely arises from the fact that no skilled and tedious glass working operations are required, it has been found that the controlled movement of the armature I4 and wire I3 results in a uniform product of high efficiency and dependability.

While I have described my invention by reference to a particular embodiment thereof it is to be understood that it is not limited thereto, but that various omissions, substitutions and changes, within the scope of the appended claims, may be made therein without departing from the spirit of my invention. f

I claim as my invention:-

l. An electric circuit maker and breaker comprising a sealed envelope, two fixed contacts sealed into said envelope, a relatively long bridging member extending between said contacts, said xed contacts being spaced apart a distance slightly less than the length of said member whereby each end of said member engages one of said contacts, means comprising smooth metal strips connected to said contacts to prevent axial displacement of said member, means independent of said envelope and insulated from said contacts to prevent movement of said member beyond the edges of said strips, and a magnet izable body loosely connected to said bridging member.

2. An electric circuit maker and breaker comprising a sealed envelope, two xed contacts within said envelope, means within said envelope to space said contacts a fixed distance apart, said means consisting at least in part of insulating material, a relatively long bridging member extending between said contacts with each end resting upon one of -said contacts, means to prevent axial displacement of said member, means independent of said envelope to limit the movement of said member` away from said contacts, and a magnetizable body loosely connected to said bridging member.

3. An electric circuit maker and breaker comprising a sealed envelope, two xed contacts sealed into said envelope, a relatively long bridging member extending between said contacts, said xed contacts being spaced apart a distance slightly less than the length of said member whereby each end of said member engages one of said contacts, means comprising smooth metal strips connected to said contacts to prevent axial displacement of said member, means within said envelope to rigidly space said strips and to prevent rotation thereof with respect to each other, said means consisting at least in part of insulating material, means independent of said envelope to prevent movement of said member beyond the edges of said strips and a magnetizable body loosely connected to said bridging member.

4. An electric circuit maker and breaker comprising a sealedenvelope, two fixed contacts metal strips connected tosaid contacts to prevent within said envelope, an insulator mounted upon axial displacement of said member,a slotted guide each of said contacts and locked against rotamember mounted on said insulator separating tion thereon, means within said envelope. to means adjacent each contact to prevent move- '5 separate said insulators by a fixed distance and ment of said member beyond the edges of said to prevent the relative rotation thereof,y a relastrips, and a magnetizable sleeve looselyv mounted tively long bridging member extending between upon said bridging member betweensaid guide said contacts with each end kthereof resting upon means.

one of said contacts, means comprising smooth JOHN P. RUTH.

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