US2393385A - Arc extinguishing means - Google Patents

Description

Jn, 22, 1946. E. w. LANnMx-:IER 2,393,385

ARC EXTINGUISHING MEANS Filed March 29, 1944 2 Sheets-Sheet 1 Jan. 22, 1946. E. w. LANDME|ER ,2,393,335

ARC-EXTINGUISHING MEANS Filed maren 29, V1944 2 sheets-sheet 2 BY @W Patented Jan. 22, 1946 A-RC EXTINGUISHlN-G MEANS Edwin W. Landmeier, Erlanger, Ky., assigner to The Wadsworth Electric Manufacturing Company, Covington, Ky., a corporation of Kentucky ApplicationMarch 29, 1944, Serial No. 5,218,543 9 Claims. A(Cl. 20G-151) The vpresent invention relates to arc extinguishing means and has for an object the Provision of a quickly attachable and detachable device for associating with a switch jaw.

Another object of the invention is to provide a device of this kind which is easily produced in quantity 'by inexpensive operations and from stock materials which cany be cut and stamped but are not readily molded.

Still another object of the invention is to provide a device of the character indicated that will emciently extinguish the arc in the control of high voltage electrical currents according to Underwriters Laboratory tests, and that will withstand charring and blistering during long vcontinued use.

Further object of the invention is to provide a switch jaw of simplified construction that is suitable for receiving the arc extinguisher of the invention.

These and other objects are attained by the means described herein and disclosed in the accompanying drawings, in which:

Fig. 1 is a top plan View of a two pole switch embodying the invention.

Fig. 2 is an enlarged sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is an enlarged fragmental side elevational view showing one side of a switch jaw and arc extinguisher `of the invention.

Fig. 4 is an enlarged fragmental side elevational view showing the opposite side of the structure of Fig. 3.

Fig. 5 is an enlarged rear elevational view of the structurefof Figs. 3 and 4.

Fig. 6 is an enlarged front elevational view o the structure of Figs. 3 and 4.

Fig. 7 is a sectional view taken on line 1--1 of Fig. 4.

Fig. 8 is a perspective view of a switch jaw structure of the invention.

The use of arc lextinguishers or arc snuffers in connection with electrical switches is known and various designs employing different materials have been used. In most instances the heretofore known devices have been accompanied by disadvantages which in practice have left much to be desi-red for one or more reasons. Cold molded materials, such as porcelain are subject to blistering when subjected to the intense heat of an electrical arc, despite the fact that high temperatures are used to lire the porcelain parts in the manufacture thereof. Asbestos material has also been found somewhat unsatisfactory. Hard fiber has arc extinguishing properties that are not to utilize the superior arc extinguishing properties of hard fiber or other sheet insulation and to at the same time utilize parts that can be punched and cut from stock pieces of the material, a. novel arrangement has been provided by the present invention for enclosing the switch jaw by an inexpensive and easily removable assembly of parts. The device of the present invention serves to prevent a dash-over toan opposing pole or to the enclosure for the switch embodying the device of the invention.

In Fig. 1 -of the drawings an insulating base Ill is suitably secured to a member II, which may be the back wall of a switch cabinet (not shown), and said base I0 has secured to it a copper switch jaw assembly l2 and acopper hinge assembly I3 yfor each pole of the switch. The base I4 of said hinge assembly I3 has associated therewith a fuse clamping means l 5 while a complementary fuse clamping means I6, including a solderless connector -II is mounted in 4alignment with each assembly I3 on an `aux-iliary insulating base I8. The fuse clamping means herein illustrated are Athe subject of my United States Letters Patent No. 2,355,085, issued August 8, 1944, 'but any other means and method may be employed in lieu thereof for mounting fuse I9 inthe ci-rcuitto be controlled bythe switch.

The switch jaw mounting of the present invention is effected in a novel Varrangement and in an economical manner. Instead of providing separate narrow slots for the reception of the respective jaw elements by a milling cutter operation, I make a single slot 22 of double width in the base by a punch and die operation and secure both of the jaw elements 20 therein. This mode is both faster and cheaper. The two jaw elements are formed for face to face abutment at the bottom and are entered together as a unit .in slot 22 where they are sweated in place or otherwise fixed in good electrical and rigid ymechanical connection. A suitable lateral projection r2li is provided on the outer .faces of elements 20 for example by forming an integral rib vas shown. I'he free ends of the jaw element 20 are spaced in .known fashion at the top to receive between them a switch blade such as 240 hingedly mounted on assembly I3. The projections 23 in the present arrangement serve to impart a desired degree 4of resiliency to the free ends of vthe jaws and they also serve as ya means to cooperate 'in properly positioning the hereinafter described self holding and removably mounted arc extinguishers.

The removable clapper type extinguisher is indicated generally at 24 and comprises a pair of hard ber side plates 25 and 26 of similar shape and size (see Figs. 3 to 7). Each of said plates has a notched lug 21 on the front edge thereof, the lug 21 of plate 25 being received in an edge notch 28 in a iiber end plate 29. The notch of lug 21 is hooked over the body of end plate 29 in a rigidly interlocked relation. A small angle plate 30 rigidly connects plates 26 and 29 at right angles near the bottom of said plates with the aid of rivets 3| and 32. The lug 21 of plate 25 is passed through an aperture 33 in end plate 29, and the notch in said lug receives and guides upon the bottom edge of aperture 33 in said end plate.

The end plate 29 traverses the edges of plates 25 and 26 and forms a closure for the space be tween said edges, but at the same time permits the relative movement of plates 25 and 26 and the consequent changing of the intervening space. Since plate 29 would normally be uppermost and in a horizontal position, the end plate 29 bailles the free escape of the arc generated as the switch blade leaves the switch jaw. By` the arrangement described the combined advantages of a clapper type extinguisher and an enclosed type mounting are had in a very simple and easily removable device.

Fixed to the bottom part of each of the fiber side plates 25 and 26, by means of rivets 34, is a sheet metal part 35 having an inturned and rounded portion forming a fulcrum member 36 which engages below the projection 23 on the 4switch body member 29. A spring clip 31 embraces the end plate 29 and side plates 25 and 26, and is provided with spring arms 38 with inturned ends entering in small perforations in said side plates. The clip 31 urges the side plates toward each other and yieldingly retains the fulcrum members 36 on opposite sides of the switch body. Each of the side plates 25 and 26 has a piece of hard ber tubing 39 rigidly mounted on the inner face thereof by means of a stiff wire 40, the ends 4l oi which are passed through said plates and bent over onto the outer faces of said plates. The tubes or lips 39 are normally in longitudinal tangential contact with each other as shown in Figs. and 7 and are yieldingly retained in the relation by the action of spring clip 31. It will be noted that one arm 38 of the spring clip 31 passes through an opening 42 in end plate 29 to permit the desired relative movement of side plates and 26.

From the foregoing and by reference to Figs. 5, 6 and '1, it will be seen that the side plates 25 and 26 may be spread apart against the resistance of spring 31 in order to permit the arc extinguishing means to be passed over the switch jaw elements 29 and to position the rounded fulcrum members 36 below the projections 23 on the switch jaw elements. The action of spring 31 will normally hold the parts in position as shown in Fig. '1 for example wherein the hard ber lips 39 are in contact with each other and the fulcrum members 36 are held against opposite sides of the switch jaw. In order to prevent longitudinal displacement of the arc extinguisher on the switch jaw, the metal ports 35 are provided with lugs 43 at each end (see Figs, 4 and 6), and loosely embrace the lower part of the switch jaw. The line of contact between lips 39 is substantially centered with the opening in the switch jaw and,

in use, the switch blade 24, during circuit closing operation, will force the lips 39 apart against the yielding resistance of spring 31 and enter the switch jaw. Upon further movement of the switch blade into the jaw, the back trailing edge of blade 24 may pass below lips 39 which are thereupon closed over the switch blade. Removal ci the switch blade from the jaw again spreads lips 39 and allows them to snap together under the force of spring 31 as soon as the blade leaves said lips.

Due to the exceptional eiiiciency of the arc extinguisher of the present invention it is possible to eliminate the derogatory effects of the arc on both the switch elements and the body of the arc extinguisher. This is derived by cutting off the arc by the nterposition of the lips 39 between the jaw and the blade, and at the same time utilizing the collapse or return movement of the sides as the motivating force for creating one or more air blasts above and very close to the top of the switch jaw. In the present embodiment there is provided in the fiber end plate 29 a narrow transverse slot 45 while at least one of the side plates, for example plate 25 is also provided with a narrow slot 46. When plates 25 and 26 snap together as the blade 24 passes beyond the lips 39 the are is cut off by the lips 39 and almost simultaneously the expulsion of air through slots 45 and 46 tends to break up and expel the arc and much of its incidental heat through said slots. During the switch movement the side plates 25 and 26 were free to rock on their fulcrum bearings with a typical hinge movement limited at the top by the travel of lug 21 on side plate 25 in the aperture 33 in the extended portion of end plate 29.

It is to be understood that the provision of the aforementioned slots 45 and 46 are desirable when the extinguishers are used in connection with switches carrying powerful currents where heavy arcing is produced. In cases where lighter arcing is produced, it is suiiicient to omit the slots and blow the arc out between the lips 39.

As an added means for assuring the proper spring functioning of the device a second spring clip 41 of a design similar to spring clip 31 is employed to embrace the metal parts 35. The inturned ends of spring 41 enter perforations 46 in the members 35. In the embodiment shown in Fig. 4 the parts 35 are provided with alternative sets of perforations 48 so that spring clip 41 may be positioned to embrace the structure from the rear as shown, or it may be applied from the iront, that is to say from the same end as spring clip 31. With the clip 41 applied from the rear end as shown, it is necessary to first remove the clip 41 in order to separate the arc extinguisher device from the jaw. If it is desired however that the mounting and removal of the arc extinguishing device of the invention is to be effected without disturbing the clip 41, then `the clip 41 is mounted to embrace extinguisher structure from the front.

It is to be noted that the device of the present invention maintains a constant baille or closure across the edges of the relatively movable clappers or sides 25 and 26 and thus prevents free escape of even a most violent arc in that critical instant when the switch blade leaves the switch jaw, and while the clappers or side 25 and 26 are still held apart by engagement of lips 39 on the sides of the switch blade.

The devices of the invention thus provide the advantages of a relatively simple and easily removable arc extinguisher and at the same time provide superior control against the possibility of a. flash-over.

What is claimed is 1. In combination, a switch jaw having projections near the bottom on opposite sides, a pair of stamped insulating side plates fulcrumed on opposite sides of said jaw below the projections and extending upwardly and beyond the top of said jaw, a stamped insulating end plate secured to the edge of one of said side plates and having limited guide movement over the corresponding edge of the other of said side plates, a pair of insulating rib members fixed to the respective side plates and normally abutting. over the longitudinal center of said jaw, and means yieldingly urging the plates toward one another for retaining the ribs together and holding the plates in fulcrumed relation to the sides of the jaw, certain of said insulating plates having a restricted opening above the level of the top of the jaw and below said ribs.

2. A removable arc extinguishing device for a switch jaw, comprising a pair of stamped insulating side plates of substantially similar shape, a stamped insulating end plate fixed .to an edge of one of said side plates and guidingly movable over the corresponding edge of the other of said plates, fulcrum members in inwardly offset relation at the bottoms of said side plates, insulating ribs fixed to adjacent faces of said side plates near the tops thereof and terminating in abutment with said end plate, and spring means yieldingly urging the parts together, at least one side plate having a restricted aperture therethrough below the rib.

3. A removable arc extinguishing device for a switch jaw comprising a pair of substantially similar stamped insulating side plates, an insulating rib and a fulcrum member disposed adjacent the top and at the bottom of each of said side plates, a stamped insulating end plate abutting corresponding edges of said side plates and iixed to one of said edges, certain of said plates having slot-like apertures below the level of the ribs and a spring clip member embracing the end plate and side plates and yieldingly urging the ribs and fulcrum members of the side plates together.

4. An arc extinguishing device comprising a pair of substantially similar stamped insulating side plates, integral notched lugs adjacent the top of the forward edges of said plates, a stamped insulating end plate having an edge notch and an aperture in spaced relation near the top thereof for receiving the notched lugs of said side plates whereby one of said side plates is fixed to the end plate and the other of said side plates is adapted for limited guide movement on the end plate, said plate being further provided with a narrow slot below the level of its notch and aperture, a spring clip embracing the end plate and normally urging the side plates toward one another, an insulating rib on the inner face of each side plate and adapted for mutual abutment under the inuence of the spring clip, metal fulcrum members secured to the bottoms of the respective side plates for engagement with the opposite sides of a switch jaw whereby .the side plates are mounted for rocking movement on such switch jaw, and lugs on opposite ends of said metal fulcrum members for precluding longitudinal displacement thereof.

5. In a device of the class described the combination of a hard liber end plate, a pair of hard iiber side plates disposed in edgewise abutment with a face of said end plate, one of said side plates being fixed t0 the end plate, the other of said side plates having limited guiding movement on said end plate, spring means urging said side plates toward each other, hard liber rib member in parallel relation on adjacent faces of said side plates and normally abutting each other under the influence of the spring means, and fulcrum members at the bottoms of the side plates for engaging a switch jaw near the base thereof, said hard ber plates having narrow restricted venting slots therethrough.

6. In a removable arc extinguisher means for a switch jaw, the combination of a series of hard 'ber elements adapted to substantially surround an end, opposite sides, and the top of switch jaw, said elements secured together to form a pair of relatively movable units, spring means normally holding the elements together and permitting yielding separation thereof under the influence of an entering switch blade and permitting snap return of the parts on withdrawal of a switch blade, certain of said elements having restricted vent apertures therethrough for the expulsion of air upon snap return movement of the units under the influence of the spring means.

7. A removable clapper type arc extinguisher comprising a pair of insulating side plates, each plate provided at its bottom for fulcrumed bearingy against opposite sides of a switch jaw and an end plate interlocked with the end edges of said side plates and closing the space between said pair of plates at one end thereof and permitting relative movement of said side plates on their fulcrumed bearings.

8. A clapper type arc extinguisher comprising a pair of insulating members having bottom edges adapted. for fulcrumed bearing on opposite sides of a switch jaw, means for yieldably and removably retaining them on such jaw, and an insulating end plate having fixed connection with an end edge of one of said side plates and an interlocked sliding connection with the corresponding edge of the other of said side plates.

9. In combination, a switch jaw having porjections near the bottom of its opposite sides, a pair of insulating clapper sides arranged at the bottoms thereof for fulcrumecl bearing on opposite sides of the switch jaw below the projections on the jaw, an insulating end plate having interlocked connection with adjacent edges of said side plates and permitting lateral and hinged relative movement of said side plates, and means yieldably urging the clapper members together for yieldably and removably supporting the clapper in a normally closed position on the switch jaw.

EDWIN W. LANDMEIER.

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