US2316470A - Switch construction - Google Patents

Description

April 13, 1943. H. A. TRIPLE-Vr 2,316,470

ASWITCH CONSTRUCTION April 13, 1943. H. A. TRIPLETT 2,316,470

SWITCH coNsTRUcTIoN Filed Aug. 2, 1940 3 Sheets-Sheet 2 v f /6 Q CGS/6 @6 @7 if April 13, 1943. H A, TRlpLE-r 2,316,470

SWITCH CONSTRUCTION Filed Aug. 2, 1940 3 Sheets-Sheet 3 Patented Apr. 13, 1943 SWITCH CONSTRUCTION Hugh A. Triplett, Wilmette, Ill., assigner to Schweitzer & Conrad, Inc., Chicago, Ill., a cor.- poration of Delaware Application August 2, 1940, Serial No. 349,709

11 Claims.

This invention relates, generally, to electric switches, and it has particular relation to switches that are provided with means for extinguishing arcs drawn on operation thereof.

An object of this invention is .to provide arc extinguishing means which will evolve an arc extinguishing medium when subjected to the heat of an arc and which will be substantially unaffected by moisture in the atmosphere and will maintain its shape without warping.

Another object of this invention is to provide arc extinguishing means in the form of yrings of fiber stacked one above the other.

Still another object of this invention is to prevent warping of the rings of fiber by stacking them so that the grains in the rings run in different directions.

Still another object of this invention is to provide for extinguishing an arc in a switch between the inner surface of .a sleeve and the outer surface of a plug of insulation.

It is another object of this invention to form the sleeve of insulation by a stack of fiber rings.

It is another object of this invention to provide ior extinguishing the arc drawn on separation of a plug-like switch member from a cooperating metallic sleeve by drawing the arc in the space between a sleeve and plug of insulation.

Other objects oi this invention will, in part, be obvious and in part appear hereinafter.

For a more complete understanding of the nature and scope of this invention, reference may be had to the following detailed description, taken in connection with the accompanying drawings in which:

Figure 1 is a view, in front elevation, of a circuit interruptor in which the present invention is embodied;

Figure 2 is a detail sectional view, at an enlarged scale, taken along the line 2-2 ofFigure 1;

Figure 3 is a detail sectional view, at an enlarged scale, taken along ythe line 3-3 of Figure 1 but showing the switch members in the switch closed position;

Figure 4 is a perspective View of some of the fiber rings illustrating how they are stacked;

Figure 5 is a detail sectional view, taken along the line 5-k--5 of Figure 1, but showing the switch members in the switch closed position;

Figure 6 is a longitudinal sectional view of an alternate switch construction to that shown in Figure 3;

Figure 7 is a detail sectional View taken aloneI the line 1-1 of Figure 6;

Figures is a longitudinal sectional view illustrating another embodiment of the invention; and

Figure 9 is a detail sectional View taken along the line 9-9 of Figure 8.

Referring now particularly to Figure 1 of the drawings, it will be observed that the reference character I0 designates a suitable support for stationarily mounting insulating cross .members ll between which are clamped insulating sleeves I2 which have extensions i3. Between each pair of sleeves I2 and I3 there is positioned a metallic plate I4 having an extension I5 that permits ccnnection of a line conductor thereto. The metal lic plates I4 are also provided with pairs of generally U-shaped switch members, Figure 5, each of which is arranged to receive a pair of spring contact fingers I1. The contact fingers l1 are mounted on and .electrically interconnected by a metallic yoke L8 .that is .carried on a suitablesupport member I9 extending from a conventional type operating mechanism 20. It will be understood that the support member I9 is movable vert-ically under the Ycontrol of the operating mechanism 20 'in .order to operate the switch to the closed and open positions.

In Figure 3 of .the drawings are shown the details of construction of one .of the pairs of cooperating switch members provided with arc extinguishing means in accordance with this invention. As there illustrated, -a metallic sleeve 24, which forms a generally cylindrical stationary switch member, is threaded into the metallic plate I4. The vlower end Aof .the insulating sleeve vI2 and the upper end of the extension I3 are threaded, as shown, .onto the ends of the cylindrical switch member 24.

The cylindrical switch member 2# is provided at its lower end with an inwardly extending c ontact section 25 for engaging .contact fingers 2t which form a part of a movable plug-like switch member. The contact fingers 25 are ,integrally for-med with a metallic sleeve 21 that is threaded onto a metallic rod .278 the lower `end of which .extends through suitable ilanged washers 22 ,and is clamped by ,suitable means, such as a nut, to the end ofthe yoke I3. A sleeve 3i) of insulation surrounds the ,portion of the rod 2S between the lower vsurface .of the metallic sleeve 21 and the top of the upper -iiange washer 29.

The .pluglike switch member formed by the contact ners 2'6 'is arranged .to move through a llore 3l that is formed in a sleeve of insulation made yup by fiber washers `32 stacked one above vthe other.

The Washers 32 are `formed of liber because this material evolves water vapor when subjected to the heat of an arc which assists in deionizing the arc space and tends to prevent re-striking as well as assisting in extinguishing the arc. The iiber in the form of washers is employed instead of a continuous sleeve of fiber in order to minimize warping. When a continuous tube of fiber is subjected to the moisture in the atmosphere, it tends to warp. In many instances the slight warping of the fiber tube which takes place may be unimportant because close clearances are not involved. However, where close clearances are involved and it is desired to maintain the diameter of the bore 3| substantially uniform throughout the life of the apparatus, it is preferable to employ a stack of ber washers 32. In order to further minimize the effects of warping, the washers 32, as shown in Figure 4 of the drawings, are stacked so that the grains, as indicated by the arrows 33 and 34, run in different directions in adjacent washers.

It will be noted that the stack of ber washers 2 is located within the extension I3 and is held gainst the under side of the cylindrical switch member 24 by means of a nut 35 that is threaded into the lower end of the extension I3.

It will be understood that, when the plug-like switch member formed by the contact ngers 26 moves downwardly and out of engagement with the contact portion 25 of the cylindrical switch member 24, an are will be drawn therebetween if the circuit in which the switch is connected has current flowing therein. This arc will play upon the bore 3| and, as described, will evolve therefrom an arc extinguishing medium. It is desir rable to further confine the arc. For this purpose, a plug of insulation in the form of a stack of fiber washers 31 is arranged to be moved into the bore SI so that the arc is confined between the convex outer' surface 38 of the washers 31 and the bore SI. The plug is formed by the stack of iiber washers at 31 for the same reason that the sleeve is formed by the stack of fiber washers 32.

It will be observed that the stack of fiber washers 31 is mounted on a sleeve of insulation 39 which has a flanged head 40. The sleeve of insulation 39 is threaded at its lower end on an integrally formed threaded portion 4I of the rod 23. A metallic washer 42 is interposed between the lowermost fiber ring 31 and the upper end of the rod 28.

When the switch construction just described is operated to the open circuit position under the control of the operating mechanism 20, the contact ngers I1 rst move out of engagement with the U-shaped switch members I6, Figure 5. The ent-ire now of current then is between the cylindrical switch member 24 and the plug-like switch member formed by the contact fingers 26 in each of the switch units. Continued downward movement of the yoke I8 and the rod 28 finally causes the contact fingers 26 to separate from the contact portion 25 of the cylindrical switch member 24 and, as previously described, an arc is drawn therebetween. This are plays upon the bore 36 of the fiber washers 32 and evolves therefrom the arc extinguishing medium. The contact ngers 26 move downwardly through the bore 3I and are followed by the plug of insulation formed by the fiber washers 31. The arc is then confined between the outer surface 38 of the fiber washers 31 and the bore 3I and is quickly extinguished.

When the switch is operated from the open position, as shown in Figure 1, to the closed position, the contact ngers 26 nrst engage the cylindrical switch member 24, and then the con- 75 tact fingers I1 engage the U-shaped switch mem- :bers I6. Because of this sequence of functioning, no arcs are formed between the contact fmgers I1 and the U-shaped switch members I6 since the circuit is never completed or opened thereby.

In Figures 6 and 1 of the drawings there is shown a construction which is similar to that shown in Figure 3 of the drawings and in which the present invention is embodied. Mounted on the plate 46 and secured thereto by suitable means is a metallic cup 41 which is adapted to receive the lower end of a corrugated insulator 48 that may be formed of porcelain. The lower end of the insulator 48 is held in position in the cup 41 by suitable cement 49. A deformable washer 5D is provided between the extreme lower end of the insulator 48 and the upper adjacent surface of the metallic cup 41.

The metallic plate 46 is provided with a cylindrical extension 5I onto which a sleeve 52 of insulation is threaded. The extension 5I forms a cylindrical switch member with which contact fingers 53, forming a plug-like movable switch member, are adapted to have contact engagement. The contact fingers 53 are integrally formed with a metallic sleeve 54 and are spring-urged radially outwardly by their inherent resiliency. Their outward movement is limited by means of an arcing ring 55 which loosely ts about the upper ends of the Contact ngers 53. It will be observed that the metallic sleeve 54 is threaded onto a metallic rod 56 which is arranged to be connected to another terminal of the circuit and is adapted to be moved in a vertical direction by suitable operating mechanism, not shown. A sleeve 51 of insulation surrounds the lower portions of the contact ngers 53 and extends over the rod 56. A nut 58 threaded onto the rod 56 serves to hold the sleeve 51 of insulation in place.

The plug-like switch member formed by the contact fingers 53 is arranged to move longitudinally through a bore 59 that is formed in a sleeve of insulation made up by a stack of fiber rings or washers 60. The sleeve of insulation is made up by the ber rings or washers 60 for the reasons fully set forth hereinbefore. The stack of fiber washers 60 is enclosed by the sleeve 52 `and is held therein in the desired position by means of threaded rings 6I and 62 at its ends.

The rings 55 and 6I form auxiliary arcing contact members between which the arc is drawn on operation of the switch to the open position. They are provided to prevent pitting of the switch members formed by the extension 5I and the contact fingers 53. Since they are subject to erosion due to arcing, they are made so as to be readily replaced. Preferably they are formed of silver tungsten or other arc resisting material.

Mounted on the rod 56 and movable therewith is a stack of fiber rings or washers which form a plug of insulation. 'Ihe arc that is drawn between the rings 55 and 6I is arranged to be confined between the outer surface 66 of the fiber washers 65 and the bore 59 as previously described. The fiber washers 65 are mounted on a sleeve 61 of insulation which is provided with a hanged head 68 that holds the stack in place. rIhe sleeve 61 is threaded onto an extension 69 which is integrally formed with the rod 56. A metallic washer 'I0 is provided at the upper end of the rod 56 and underneath the lowermost washer 65 for assisting in holding the stack in place.

The operation of the switch construction shown in Figure 6 will be essentially the same as that described for the switch construction shown in Figures l and 3 and, hence, will not be set forth in detail here.

In Figures 8 and 9 of the drawings still another embodiment of the invention is disclosed. As there shown, a tubular insulating housing 14 is provided and is preferably formed of porcelain. At the ends of the housing 14 line terminals 15 and 16 are provided for connection to line conductors, as will be readily understood. The line terminals and yHi are in axial alignment and carry metallic sleeves 11 and 18 with which are integrally formed contact ngers 19 and 80 that form generally cylindrical switch members. The free ends of the contact fingers 19 and 89 lare biased radially inwardly by garter springs 8| and 82.v Associated with the cylindrical switch members formed by the contact ngers 19 and B0 are sleeves 83 and 84 of insulating material, such as from which an arc extinguishing medium is evolved when subjected to the heat of an arc.

It will be observed that the insulating sleeves 83 and S4, as well as the cylindrical switch members provided by the contact fingers 19 and 80, are in axial alignment for receiving a bayonet type switch member shown generally at 88, endwise therethrough. The bayonet switch member 98 is provided with plug- like switch members 89 and 99 at its ends for contact engagement with the adjacent contact fingers 19 and 80 in the switch closed position as shown. The plug- like switch members 89 and 90 are interconnected by a metallic rod 9| which is surrounded by a sleeve 92 of insulating material such as ber. like switch member 89 is provided with an extension 93 that is secured to an insulating handle member 94.

Associated with the lower plug-like switch member Sil is a sleeve 95 of insulation such as fiber, which is held in place by a screw 96.

When the handle 94 and the bayonet member 48 attached thereto are withdrawn from the housing 14, it will be observed that the circuit between the terminals 15 and 16 is opened at two points. That is, it is opened between the lower ends of the contact fingers 19 and the plug-like switch member 89, `and also it is opened between the upper ends of the contact ngers 89 and the associated plug-like switch member 90. It will be noted that the two arcs thus formed are in series circuit relation. The arc that is drawn between the switch members 8| and 89 is conned between the bore 91 in the sleeve 83 and the outer surface 98 of the sleeve 9|. Because of the arc extinguishing material that is evolved from these surfaces and, further, because the arc is confined, its extinction is facilitated. The arc that is formed between the switch members 8U and 9D is likewise confined between the bore 99 of the sleeve 84 and the outer surface 98 of the sleeve S2. In the manner above described, the extinction of this arc is facilitated.

Since certain changes can be made in the foregoing constructions and different embodiments of the invention can be made Without departing trom the scope thereof, it is intended that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted vas illustrative and not in a limiting sense.

What is claimed as new is:

1. In a dry type circuit interrupter, arc extinguishing means comprising a plurality of rings The plugof fiber stacked one above the other and providing a bore therethrough of substantially uniform diameter in which the arc is drawn.

2. In a dry type circuit interrupter, arc extinguishing means comprising a plurality of rings of fiber stacked one above the other and providing a substantially uniform convex cylindrical surface over which the arc is drawn.

3. In a circuit interrupter, arcextinguishing means comprising a plurality of rings of liberl stacked one above the other so as to provide a cylindrical surface with the grain of the fiber in the rings running substantially at right angles to the longitudinal axis of said cylindrical surface, whereby substantially no transverse expansion takes place and the diameter thereof remains substantially unchanged with variations in moisture content of said rings.

4. In a circuit interrupter, arc extinguishing means comprising a plurality of rings of ber stacked one above the other so as to provide a bore with the grain of the fiber in adjacent rings running in different directions in planes at right angles to the longitudinal axis of said bore whereby substantially no transverse expansion takes .place and the internal diameteithereof is maintained substantially unchanged with variations in moisture content of said rings.

5. In a circuit interrupter, arc extinguishing means comprising a plurality of rings of fiber stacked one above the other so as to provide a convex cylindrical surface with the grain of the fiber in adjacent rings running in different directions in planes at right angles to the longitudinal axis of said cylindrical surface whereby substantially no transverse expansion takes place and the diameter thereof is maintained substantially unchanged with variations in moisture content of said rings.

6. In a dry type circuit interrupter, in combination, a pair of separable switch members between which an arc may be drawn, a sleeve formed by a plurality of fiber rings of uniform internal diameter stacked one above the other and fastened to one switch member, and a plug of insulation fastened to the other switch member, said plug and associated switch member -being movable through said sleeve and the arc between said switch members being confined in the space between said sleeve and plug.

7. In a dry type circuit interrupter, in combination, a pair of separable switch members between Which an arc may be drawn, a sleeve formed by a plurality of ber rings of uniform internal diameter stacked one above the other and fastened to one switch member, and a plug formed by a plurality of rings of ber of uniform external diameter stacked one above the other and fastened to the other switch member, said plug and associated switch member being movable through said sleeve and the arc between said switch members being conned in the space between said sleeve and plug.

8. In a dry type circuit interrupter, in combination, a pair of separable switch members between which an arc may be drawn, one of said switch members being generally in the form of a metallic sleeve and the other being generally in the form of a metallic plug, a sleeve of insulation formed by a plurality of fiber rings of uniform internal diameter stacked one above the other and fastened coaxially to said one switch member, and aplug of insulation fastened coaxially to said other switch member, said other switch member and plug of insulation carried thereby being movable through said one switch member and said sleeve of insulation whereby the arc between said switch members is confined in the space between said sleeve and plug of insulation.

9. In a dry type circuit interrupter, in combination, a pair of separable switch members between which an arc may be drawn, one of said switch members being generally in the form of a metallic sleeve and the other being generally in the form of a' metallic plug, a sleeve of insulation formed by a plurality of fiber rings of uniform internal diameter stacked one above the other and fastened coaxially to said one switch member, and a plug of insulation formed by a plurality of liber rings of uniform external diameter stacked one above the other and fastened coaxially to said other switch member, said other switch member and` plug of insulation carried thereby being movable through said one switch member and said sleeve of insulation whereby the arc between said switch members is conned in g the space between said sleeve and plug of insulation.

l0. In a dry type circuit interrupter, in combination, a pair of generally cylindrical switch members and means for stationarily mounting the same in insulated spaced relation, a pair of plug-like switch members and means electrically connecting and mounting the same for movement into and out of engagement with said generally cylindrical switch members, a sleeve of insulation formed by a plurality of fiber rings of uniform internal diameter stacked one above the other and fastened coaxially to each cylindrical switch member, and a plug of insulation fastened coaxially to each plug-like switch member, each plug-like switch member and its plug of insulation being movable through the corresponding cylindrical switch member and its sleeve of insulation whereby two arcs are drawn in series and the arc drawn between each cylindrical switch member and the cooperating plug-like switch member is coniined in the space between the associated sleeve and plug of insulation.

l1. In a dry type circuit interrupter, in combination, a pair of generally cylindrical switch members and means for stationarily mounting the same in insulated spaced relation, a pair of pluglike switch members and means electrically connecting and mounting the same for movement into and out of engagement with said generally cylindrical switch members, a sleeve of insulation formed by a plurality of fiber rings 0f uniform internal diameter stacked one above the other and fastened coaxially to each cylindrical switch member, and a plug of insulation formed by a plurality of fiber rings of uniform external diameter stacked one above the other and fastened coaxially to each plug-like switch member, each plug-like switch member and its plug of insulation being movable through the corresponding cylindrical switch member and its sleeve of insulation whereby two arcs are drawn in series and the arc drawn between each cylindrical switch member and the cooperating plug-like switch member is conned in the space between the associated sleeve and plug of insulation.

HUGH A. TRIPLETT.

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