US1914129A - Arc quencher for safety switches - Google Patents

Description

3 Sheets-Sheet 1 0. 5. JENNINGS ARC QUENCHER FOR SAFETY SWITCHES Filed April s, 1928 June 13, 1933.

IIIIIIII-lll ll- INVENTOR 0/ /'v,er 5 Jennings BY ATTORNEY June 13, 1933. o.- s. JENNINGS ARC QUENCHER FOR SAFETY SWITCHES Filed April 5, 1928 3 Sheets-Sheet 2 INVENTOR Oliver 5. Jennings ATTdRNEY June .13, 1933. 0.5. JENNINGS 1,914,129

ARC QUENCHER FOR SAFETY SWITCHES Filed April 5, 1928 a Sheets-Sheet 5 INVENTOR Oliver 5. Jennings KTTD RNEY Patented June 13, 1933 "UNITED STATES PATENT OFFICE 0mm 8. M68, OI! KAISFIELD, OHIO, l; IARUI'AOTUBING COMPANY, A CORPORATION 01' PENNSYLVANIA ABC QUEN'CEEB. FOB SAFETY SWITCHES Application fled April 5,

My invention relates to switch mechanisms and particularly to enclosed switch mechanism wherein the contact jaws and switch blades are enclosed within a metal housing.

5 1 An object of my invention is to provide an enclosed switch mechanism wherein the arc incident to the separation of the switch blade from the contact jaw is extinguished before the jaw or blades are injured by the arc.

10 A further object of my invention is to pro- Yide a-switch mechanism wherein the arc incidentto the separation of the switch blade from the contact jaw is transferred to an arc member that is electrically is connected to the contact jaw but which does not engage the switch blade, thereby pre-' venting'burning of the contact jaws. A. further ob ect of my invention is to provide a switch mechanism with-an arc extin- 80 gu'ishing device somewhat similar to the device shown in my co-pending application, Serial No. 606,565, filed Dec. 13, 1922, and assigned to'the Westinghouse Electric & Manufacturing Company, wherein spaced metal barrier plates are superposed over the contact jaw and are provided with slots through which the switch blade passes in'moving to open or closed position, and to provide improved means for supporting the barrier plates for eflectiv'ely extinguishing the arc and for directing the arc gases in a direction I where they willdo no harm. v

' Afurther object of my invention is to provide :a switch mechanism having the above noted characteristics wherein the arc extinguishingbarrier plates are supported upon insulating plates disposed on opposite, sides of the :switchjawv and supported on the arc contactjaw. A further object of my invention is to provide-1a switch with an arc quenchdevice that is simple in construction and .multaneous operation by means of an insu- 'which'may be read-i1 assembled and which is economical to manu acture.-

. ese and other objects thatv will be made 1p rent throughoutthe further description .of my invention are attained byv means of the apparatus hereinafter described and illusbarrier shown in Fig. 3, .taken on the line.

receiving member that is connected to the I I support the-three lmife blade switch members 18 that are movable into and out of ABSIGIlOB '1'0 WESTINGHOUSE anaemic 1928. Serial 170.287,!516. I A trated in the accompanying dra wings, wherein, v

Figure 1 is a plan view of an enclosed switc embodying features of my invention, with the cover cut-away to expose the switch mechanism, Fig. 2 is a longitudinal section through the switch mechanism shown in Fig. 1, taken on the line II-II thereof, and showing the switch mechanism in side elevation and the arc extinguishing device partly in section,

Figs. 3 and 4 are plan and side elevational views respectively, of the arc-quenching device s own in Fig. 1,

Fig. 5 is an end view of .the arc-quenching barrier shown in Figs. 3 and 6 and looking in the direction of the arrow V in Fig. 6,

Fig. 6 is a longitudinal section through the VI VI thereof,

Fig. 7" a side elevation of an insulating barrier'supporting plate,

Fig. 8 is a transverse section through the plate shown in Fig. 7, taken on the line VIII-VIII thereof,

Fig. 9 is an elevational view of a barrier plate shown in Figs. 3 and 4, and

Fig. 10 is a perspective view of the arc-receiving member and a portion of its supportin means.

'ferring to the drawings, the enclosed switch mechanism comprises a sheet metal housing 11 that is provided with a cover 12 hinged at 13 and whichis releasably retained in closed position by means of a latch 14.

Athree pole knife switch is mounted within the housing and comprises an insulating base '15 upon which are mounted three pairs of switch contact jaws 16 and three pairs of hinged jaws 17 'which serve to pivotally engagement with thecontact jaws 16.

The-switch blades 18}are connected for si- 96 -lating-bar 19 that is provided with an operating clip 21 having anfoblong opening or slot 22 through which the operating bail 23 extends. The bail 23 is ivotally mounted in the side walls ofthe ousing 11 and is provided with a movable operating handle 24 by means of which the switch may be actuated from the exterior of the housing.

The operating bail 23 is yieldingly connected to the insulating bar 19 through the medium of springs 25 which serve to withdraw the switch blades from the contact jaws with a snap action after the operating handle has been moved a predetermined distance toward open position. In the event that the blades do not snap from the contact jaws before the bail 23 engages the outer end of the slot 22, the bail will positively engage the end of the slot and force the switch blades out of engagement with the contact jaws. Contraction of the springs 25 will immediately move the blades to open position with a snap action.

The above described switch is of wellknown standard construction and no claim is made to the specific form of switch device herein illustrated and described.

My invention relates primarily to an improved arc-quenching device that is applicable to switch devices of the character described and also to other forms of switch devices, whether they be of the contact jaw and switch blade type, or of the clutch contact type.

Referring to Figs. 2 to 10, particularly, the arc-quenching device comprises an arereceiving plate 26 thatis of U-shape, having a pair of side plates 27 integrally connected by a barrier plate 28 having a slot 29 therein that registers with the spaces between the jaws of the contact jaw and through which the free end of the switch blade 18 passes in mdving to open or closed position. The

' contact jaw is provided with a pair of supporting lugs 30 disposed in staggered relation that constitute integral parts of the contact jaw and wh ch may receive attaching lugs 31 of the arc-receivingbarrier member 26, the barrier 26 being detachably secured to the lugs 30 of the contact jaw by means of screws 32.

Since the arc-receiving barrier member 26 is conductively connected to the contact jaw, the arc incident to the separation of the switch blade from the contact jaw will be transferred .to the plate 28 the instant the blade disengages from the contact jaw. Thus burning of the contact jaw is prevented. If the arc endures for any appreciable time, the burning action will occur at the point of contact of the arc with the barrier plate 28.

In the above-referred to patent application, I have disclosed a plurality of. metal spaced plates superimposed about the contact jaw and provided with slots through which the switch blade passes in moving to open or closed positions. The purpose of the plates is to provide masses of coolin material in the vicinity of the are which is rawn at 'a point My present invention relates to the manner of mounting the plates and supporting them by insulating members that determine the shape and volume of the space between the plates and which direct the arc gases in predetermined paths where they are rendered harmless and extinguished before they can expand to dangerous proximity to the walls of the enclosing housing.

With this object in view, I provide for each contact jaw, a pair of insulating plates 33, that are provided with marginal flanges 34 and 35 and transverse webs 36 which form recesses 37 therebetween, in which the sheet iron barrier plates 38, 39 and 41 are inserted, the insulating plates being retained in assembled position as shown in Figs. 3 to 6, when they have been riveted to the side plates 27 of the arc-receiving barrier member 26 by means of rivets 42 as indicated in Fig. 6.

The plates 38, 39 and 41 are provided with notches 43 that receive the flanges 34 of the insulating plates 33 which serve to prevent longitudinal displacement of the lates. The plates are also provided with s ots 44 that are aligned with one another and with the notch 29 in the arc-receiving barrier plate 28.

As indicated in Fig. 2, the plates are disposed in an angular position with respect to the insulating base 15 and are arranged in a substantially radial direction with res ct to the axes of rotation of the switch lades. When the switch blade is moved to open position, the free end thereof passes through the slots 29 and 44 in the plates 28, 38, 39, and 41.

It will be noted b referring to Figs. 1, 3 and 5, that the we s 36 of the insulating plates are of such shape that they substantially close the space between the plates in the vicinity of the inner slotted edges thereof and the space between the plates,,determined by the from the slotted front ends of the metal plates toward the rear ends thereof.

By reason of this construction, the arc .gases generated between the plates are forced to expand rearwardly instead of toward the hinged jaw of the switch and to relieve the pressure between the plates, the insulating plates 33 are provided with side 0 nings 45 through which gases may be- ISChBIfEd laterally. The rear edge of the barrier p ate 28 is cut away at 46, which permits the gases between the plates 28 and 38 to expand down- I shape of the webs, expands in volume fined by the flanges 34. Since t toward the base of the contact jaw. The

gases between the plates 38 and 39 and between the plates 39 and 41 are of reduced pressure relative to those in the space between the plates 28 and 38, and slnce the plates 39 and 41 are of increased length, they are amply adequate to reduce the temperature of the arc gases before they are discharged from the space between them.

- It has been found that by reason of the use of the arc-quenchin device above described, currents of relative y large value may be 1nterrupted without causing the discharge of the arc gases from the extinguishing unit.

The are is extinguished so rapidly that practically no burning of the switch blade occurs.

Switches are usually. rated by their capac ity to interrupt a current without Injury or destruction. The switch blades and aws may be capable of carrying considerably more current than they are capable of rupturin By increasing the rupturing capacity, t e rating of the contacts may be, materially increased without changing the contacts of the switch blades and contact jaws. By reason of the provision of the arc-quenching device, the capacity of the switches is increased without materially affecting the cost. The construction of the arc-quenchin device is of suchsimplicity that it i relatively inexpensive to manufacture and mi be assembled. By mounting the arcquenching barrier plates between insulating plates that are secured to the arc-receiving barrier plate, the arc-quenching devices may be asto any orm of switch'contacts.

device as ap switch 'aws, appearing in the claims,

sembled and handled-as a unit, which ma be applied to the contact jaw after assem ly. Inspection and repair of the barriers is facilitated by reason bf this construction.

While I have described the arc-quenching lied to a knife type switch and have claime the device as so applied, it will be understood that the terms switch blade and Pp y While I have illustrated but one embodiment of my invention, it will be/a pparent to those'skilled in the art that various changes, substitutions, additions and omissions may be made in the apparatus ilfromthe spirit and scope of my invention as set forth in the appended claims.

I claim as my invention:

- 1. Switch mechanism comprising a contact jaw, a switch .blade movable into and out of the said jaw, and a plurality of spaced metal barriers associated with the jaw and riers associated with the ings therein through which the switch blade.

ay readily having openings therein through which the switch blade passes in moving to open position,the barrier nearest to the 'aw being conductively connected thereto or preventing the drawing of an arc'between the blade and the jaw.

2. Switch mechanism comprising a contact jaw, a switch blade movable into and out of the said jaw, a plurality of spaced metal barjaw and having openpasses in moving to open position, the barrier nearest the jaw being conductively connected thereto, and insulating supports carried by the last said barrier for supporting the other barriers.

3. The combination with a contact jaw and a switch blade movable into and out of contact therewith, of an arc-quenchingdevice comprising a plurality of metal plates spaced apart and provided with aligned slots extendinginwardly from one edge and throughand insulating means 1 which the blade passes, between the plates providing an enclosed space expanding in volume from a point adj acent the slotted end of the plates toward the opposite end thereof.

4. The combination with a contact jaw and a switch blade movable into and out of contact therewith, of anarc-quenching device comprising a plurality of A metal spaced apart and provided with aligne slots extending inward through which the blade passes, and an insulating support for lates 4 1y from one edge and the barriers comprising means of insulating material having. an

inner surface extendin between the plates and having an end portion extending around .one end of the plates for directing arc gases,

in predetermined directions.

5. The combination with a contact jaw and a switch blade movable into and out of contact therewith of an arc-receiving member conductively connected to and supported from the contact device supported thereon com rising a pair of insulating plates dispose on opposite sides of the jaw and between which the switch bladepasses, and an arc-quenching metal plate supported 'therebetween and provided with an opening through which the switch blade passes.

6. The combination with a contact jaw and a switch blade movable into and out of contact therewith, of an arc-quenching device comprising a plurality of spaced metal plates having an opening through which the switch blade passes, and. insulating supporting members on opposite sides of the plates having openings registering with the spaces between the plates for the discharge of arc ases accumulating between the plates. k

7. e combination with a contact jaw and a switch blade movable into and out of contact therewith, of an arc-quenchmg dejaw and an arc-quenching vice comprising a pluralityof s aced metal plates having an opening throug which the metal blade. passes, the said plates being of increasing length from the plate nearest to the contact jaw to the outermost plate.

8. In a circuit interrupter, a contact member and a movable switch member, an arc extinguishing structure including a plurality of conducting plates having open spaces therebetween and provided with slots extending inwardly from one edge and through which said movable switch member passes,

means of insulating material extending along the sides of and supporting said plates, said insulating means also extending along one end of said plates and at least partially closing the spaces between the plates at that end, and the open spaces at the edges of the plates at the other end being unobstructed.

9. In a circuit interrupter, a contact member and a movable switch member, an are extinguishing structure including a plurality of conducting plates having open spaces therebetween and provided with slots extending inwardly from one edge and through which said movable switch member passes, means of insulating material extending alon the sides of and supporting said plates, said insulating means also extending along'the slotted end of the plates and substantially 'enclosing the spaces between the plates at that end except at the slot through which the blade passes, and the open spaces at the edges of the plates at the other end being unobstructed.

In testimony whereof, I have hereunto subscribed my name this 26th day of March,

OLIVER s. JENNINGS.

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