US3144536A

US3144536A - Interrupter attachment for disconnect switch

Info

Publication number: US3144536A
Authority: US
Inventors: Ronald P Bridges; Chester E Pierzchala
Original assignee: James R Kearney Corp
Current assignee: James R Kearney Corp
Priority date: 1961-03-22
Filing date: 1961-03-22
Publication date: 1964-08-11
Anticipated expiration: 1981-08-11
Also published as: GB983512A; GB983511A

Description

Aug. 11, 1964 R. P. BRIDGES ETAL 3,144,536

INTERRUPTER ATTACHMENT FOR DISCONNECT SWITCH 5 Sheets-Sheet l Filed March 22, 1961 A TIORNEYS y Aug. 11, 1964v I 1R. ii'rpGEsQAE-TAL', 1 i 3,144,536

NTERRUPTERATTACHMENT.F011 nlscoNNEcT .SWITCH l Filed March 22,.'1951 5 sheds-sheet 2 MAKE ANGLE".

F I G. 3

TRIPANGLEA INVENTORS RONALD P. BRIDGES Y CHESTER E. PIERZCHALA n L I Afa/fw r y AT TOR NEYS Allg. 11, 1964v P, AL .l J 3,144,536

INTERRUPTER ATTACHMENT 'DISCONNECT swITcH" Filed Mar-ch 2;;l 196i E.

n 5 Sheets-Sheet 3 INVENTORS RONALD F. BRIDGES CHESTER E. PIERZCHALA ATTORNEYS Aug. 1l, 1964 R. P. BRIDGES ETAL INTERRUPTER ATTACHMENT FOR nrscoNNEcT SWITCH 5 Sheets-Sheet 4 Filed March 22. 1961 47"! Vif,"

INVENTORS RONALD F. BRIDGES CHESTER E. PIERZCHALA QM/kwa ATTORNEY Aug. 11, 1964 R. P. BRIDGES ETAL 3,144,536

INTERRUPTER ATTACHMENT FOR DISCONNECT SWITCH 5 Sheets-Sheet 5 Filed March 22, 19,61

INVENTORS RONALD P. BRIDGES 'III lCHESTER E. PIERZCHALA mm www ATTORNEY United States Patent 3,144,536 INTERRUPTER ATTACHMENT FR DISCNNECT SWITCH Ronald P. Bridges and Chester E. Pierzchala, St. Louis, Mo., assignors to James R. Kearney Corporation, St. Louis, Mo., alcol-poration of Delaware Filed Mar. 22, 1961, Ser. No. 97,627

11 Claims. (Cl. 20G-146) This invention relates to electric switches for use in high Voltage electric distribution systems wherein operation of the switch, while under load, may result in damage to various current carrying switch elements by arcing and more specifically to an improved electric switch constructed with an arc-breaking device to minimize such damage and make possible ready replacement of such elements as'are damaged by simply performed service operations while the switch is in service. Although switches of this general description have been proposed heretofore, as an example, see the patent to Froland 2,434,315 of January 13, 1948, this invention relates to certain improvements which enhance the marketability, utility and operation of this kind of switch.

According to this invention, a high potential switch of the kind adapted to be operated remotely is modified in a way to readily accept a fitting, which is operable by an ordinary switch stick to clamp or release a compact arcbreaking device of special construction. The fittings clamp the arc-breaking device in operative position on the switch and the arc-breaking device will operate in this position to protect the switch parts from damage due to arcing when the switch is subsequently opened under load. This arc-breaking device is adapted by its construction to be readily placed in, or removed from, this fitting by an ordinary switch stick.

The switch, the fitting, and the arc-breaking device are separate articles of manufacture and may be sold separately or assembled. This provides for many different contingencies. Suppose that in a proposed electric distribution system, it is contemplated that some of the switches to be installed may be frequently operated under load, others very seldom, or only under very light loads, and still others will be present only in a stand-by capacity when installed. No matter which of these situations could exist, no increase in cost would be involved in installing a switch according to this invention which can be suitably modified to mount the fittings to accommodate an arc-breaking device. For if the need for switch operation is frequent, then the switch with fittings and arcbreaking devices can be assembled before installation. In other cases, the fittings only would be assembled with the switch before installation. In still others, only the bare switch need be purchased for installation. Anytime service demanded an arc-breaking device in the last two instances or examples, it would be purchased and installed on the switch with the fittings, or by purchasing and installing the fittings on the switch, it could be adapted .to receive the arc-breaking device. The fittings can readily be constructed to mount arc-breaking devices to match theV capacity of the particular switch or switches, which means that a Spare can be installed quickly on any switch of this kind when equipped with ttings before or after the switch is opened by using only an ordinary switch stick available to every lineman. It is also possible to speedily replace one arc-breaking device by a spare if the one in- 3,144,536 Patented Aug. 1l, 1964 This invention, however, includes not only the switch alone, or the switch and its novel fittings, to make the multi-duty switch a real possibility, but also the arc-breaking device as a separate manufacture and when combined with the switch. Not only does the arc-breaking device have its own novel features, but it is so constructed, mounted and arranged with the switch parts that it is not in shunt relation with the switch when the switch is either closed or fully open. It is, therefore, possible to replace the same with either the switch open or closed without drawing any arc between the parts. The switch parts including the arc-breaking device are so arranged, as will be later described in detail, that the arc-breaking device carries the current during only a brief interval yafter the switch is opened, but not as the switch is opened, and this feature increases its effectiveness and service life. In this respect, it differs from all prior devices of this kind whether permanent installations, such as in Froland, or portable devices which are used by the lineman and are equally wellknown in the art.

It is one of the objectsrof this invention to provide an electric switch of basic design permitting the addition of certain components which will enhance its value as a switch and improve its operation to perform its function as a disconnect.

, Itis another object of this invention to provide a basic switch construction to which additions can be made for improving its function as changes in conditions occur in the electrical system in which it is connected.

It is another object of this invention to provide an improved construction in a switch tok suppress the arc formed during its operation.

It is still another object ofv this invention to provide a switch with an arc suppressing device which may be readily replaced without putting the switch out of service.

It is another object of this invention to provide fittings attachable to a basic electric switch incorporating a mechamsm for locking or unlocking an arc suppressing device in position thereon which can be operated by the ordinary switch stick.

It is still another object of this inventionvto provide a novel arc suppressing device for a switch.

Further objects and advantages of this invention will appear from the following detailed description which is in such clear, concise and exact terms as to enable any oneskilled in the art yto make and use the invention when taken in conjunction with the disclosure in the accompanying drawings forming a part thereof and in which:

FIG. l is a side elevational View of a switch constructed in accordance with this invention;

FIG. 2 is a top plan view of the switch shown in l FIG. 1;

FIG. 3 is a schematic representation of the same switch illustrating the sequence of operational events;

FIG. 4 is an exploded view on a larger scale illustrating parts of the switch device in perspective;

IIG. 5 is a top plan view of the fitting on an enlarged sca e;

FIG. 6 is aview in vertical section through the arcbr'eak device;

FIG. 7 is apsectional view on the line 7-7 of FIG. 6;

FIG. 8'is a sectional view on the line 8-8 of FIG. 6; and

FIGS. 9 and 10 are operational views in section similar to FIG. 6.

Turning now to FIG. 1 of the drawings, the disconnect switch elements include a base 1 of channel iron of suitable dimensions. Bolted to the channel iron 1 at spaced points are a pair of brackets 2 and 3 secured to the channel iron'l by the bolts 4 and 5, respectively. Each of these'brackets in turn supports an insulator member, such as 6 and 7, secured to the brackets 2 and 3, respectively,

by

bolts

8 and 9. At the top end of the insulator 6 is a fitting 12 secured thereto by suitable bolts, not shown. This fitting includes an extension 14, the upper side of which is recessed at 16 and provided with spaced holes 18 and 20 for bolts which are used to secure a conductor between a clamping plate and the terminal 14. The fitting 12 also has bolted thereto a pair of spaced spring type of

fixed contacts

24 and 26 secured by pairs of bolts, such as 28 and 32, respectively. Both contacts are preferably identical and their free ends are bent upon themselves in a form of a U so as to provide a slot in which the end 36 of the movable arm 29 is wedgingly engaged. The fitting 12 also carries a small extension 38 mounting a stop screw 40 which limits the movement of the end 36 of the movable arm of the switch in a switch closing direction.

The insulator 7 carries a bracket 11 secured to the top of the insulator 7 by suitable bolts, such as 13, one of which is shown in FIG. 1. Bracket 11 has a circular base which seats on top of the end of the insulator 7. Divergent arms 17 carry spaced

hollow boss members

23 and 25, respectively, shown in FIG. 2. From this view, it will be apparent that bracket 11 forms the main support for the hinge contact arm 29 of the disconnect switch mechanism. Returning now to FIG. l, the bracket 11 also carries a small extension 31 projecting vertically therefrom, which in turn is apertured to receive a stop screw 33 locked in position in vthe aperture by suitable stop nuts. Whereas the two insulators 6 and 7, heretofore described, are mounted on fixed mountings in fixed position with respect to the base 1, nevertheless, they are reversible in position if it is desired to mount the switch disconnect in an inverted position. This is likewise true of the insulator 45 which is supported on a flange 46 rotatable with the vertically mounted shaft 50.

Bolts

46 and 48 attach the insulator to the flange. Shaft 50is rotatably mounted in a bearing support 52 secured to the channel member 1 by bolts 54 and 56, respectively. Bolt 56 also anchors in position a bracket 57 carrying an adjustable stop nut 59. The stop nut 59 is aligned with the end of a short arm 60 turning with the shaft 50 and limits the rotative motion of the shaft 50 in one direction. One end of the shaft 50 projects below the base 1 and may be provided with a fitting, such as 61, secured thereto against rotation, and upon which may be mounted a suitable arm for connection with a linkage to turn the shaft 50.

Supported at the top of the insulator 45 is a crank 64 suitably secured by a plurality of bolts, such as 66 and 67. The end of the crank 64 is pinned to a clevis 69 which is rotatable within a boss of the forked bracket 70. The branched arms of the bracket 70, indicated as 72 and 74, straddle the upper end 76 of a control arm 77 rigidly secured to the contact arm 29 of the switch. A

pin 75 'forms the rotatable connector between the spaced arms 72 and 74 of the bracket 70 and the control arm 77. The crank 64 has a bearing part, indicated generally as 80, journalled in an aperture within a bracket 82. On the upper surface of the bracket 82 is a recess 84 with two

bolt holes

85 and 86. This forms the terminal to receive another conductor which can be secured in the recess 84 by a suitable bracket or clamping 'plate held against the conductor by bolts passing through the

apertures

85 and 86. Y

. The hinge construction between the blade or arm 29 and its supports, bracket 11 and yoke 82, will not be described Vhere since it forms a part of the invention disclosed in an application of Joseph Bernatt, Serial No. 88,543, filed. February l0, 1961,*title: Conductive Hinge Structure for Electric Switch. This description so far has been confined to the basic elements of a known type of switch, such as described in the above application of JosephrBernatt. For a further detailed description, 'referenceishould be made to this disclosure. In the basic switch mechanism heretofore described, the contact arm 29 can pivot both on its axis and on the aforesaid hinge mechanism during its opening and closing action. Assuming the parts to be in the position indicated and it is desired to open the switch, the shaft 50 is rotated clockwise by a suitable linkage mechanism which causes the crank 64 to rotate in the same direction as the insulator 45 turns with the shaft 50. The motion of the crank 64 in turn is transmitted to the movable contact arrn 29 through clevis 69, bracket 70 and control arm 77 to twist the arm 29 on its axis thereby turning the paddle end 36 of the contact arm from a position generally horizontal as shown in FIG. 2 to a more nearly vertical position. This frees the contact pressure between the fixed-contact springs 24 and 26 and further rotation of the crank 64 then swings the contact arm 29 toward a vertical position as shown in the dotted lines, FIG. 3. The closing action of the switch is the reverse of that just described.

The invention here is concerned with protecting

thc switch contacts

36 and 24 and 26 from damage due to arcing when the switch is opened or when the switch is closed. Of course, their protection afforded bythe construction hereinafter described is applicable to most any switch by suitable modifications, but it is contemplated that its action will be the same regardless of the type of switch to which applied. Y

The protection of the switch from damage due to -arcing preferably includes two -shunt circuits'between the switch contacts, which circuits are operated sequentially to open during movement of the movable contact arm 29 from l.the

fixed

contacts

24 and 26. One of these shunt circuits is established by contact between pin in the end of the movable contact arm 29 and the stationary contacts 100 and 101 over which the pin 95 travels during opening of the switch contacts. The fixed contacts and .101 are disposed on opposite sides of the pin 95 and biased toward one another to maintain this contact with the pin 95 by

portions

99 and 97, respectively, which are co-extensive with the portions 100 and 101 andare respectively secured to the fixed contact carrying bracket 12 by the

bolts

104 and 105. So long as the switch is closed, there will be a shunt circuit established between the pin v95 and the contacts 100 and 101. As the switch is opened, this shunt circuit will continue to conduct the current from the contact arm 29 after the contact 36 has left the

contacts

24 and 26. Thus, the shunt circuit between Vthe pin 95 and the contacts 100 and 101 will continue during blade opening to substantially the angular position of the contact arm 29, as indicated by the line A on FIG. 3.

Before the blade 29 reaches the angular position A, however, it has made contact with a second shunt circuit between the movable contact 29 and the fixed contact carrying bracket 12, as will be hereinafter pointed out. The bracket 12, just mentioned, is provided to receive a detachable fititng 1-09 shown in FIGS. l, 2, 4 and 5. The fitting 109 has suitable holes 110 and 111 which mate with

holes

113 and 114 provided for that purpose in the bracket 12. The `holes 113 and 114 are tapped to receive cap screws 115 and`116 by which the fitting 109 may be secured in fixed relation to the bracket 12. Integral with the fitting 109 and suitably offset from its attaching point with the bracket 12 is aisocket 119 which is in effect a tubular sleeve formed integrally as a part of the fitting 109. The tubular passage in the socket 119 is opened at both top and bottom 'and arranged so that it will receive and'support an arc-breaking device 125 in a position substantially 'parallel with the insulator 6. 'One side of the socket 119 has a key way 122, and aligned with the key way 122 and opening thereinto isa cylindrical tapped hole springwasher 135. The end of the latch lever has an eye 138 which may be engaged by an ordinary switch stick so as to swing the latch lever and thereby the swinging latch 130 from an open position, such as shown in FIG. 5 to a closed position in which it obstructs the upper end of the open key way 122. When the latch lever 130 is moved `to open position, the socket 119 is adapted in this condition to receive the arc-breaking device 12.5. On the lower end of the arc-breaking device 125 is lower arcing chamber housing 140 which forms in effect a continuation of the arcing chamber housing 141. These two housings are interconnected by a' contact housing 142 which is dimensioned to be received in the socket 119. At the top of the contact housing 142 is a iiange 144 having a downwardly facing shoulder 145 which will seat against the upper face of the socket 119. Contact housing 142 also has a rib 146 extending vertically thereof to a point spaced from the shoulder 145 by a distance substantially the thickness of the swinging latch 130. At the upper end of the arc-breaking device 125 is in integral eye 149 by which the arc-breaking device 125 may be lifted to a position where its lower end will be received in the socket 119. The rib V146 of the contact housing 142 locates the arc-breaking device at the proper angle, and the shoulder 145 will then seat on the upper end of the socket 119. The arc-breaking device 125 and the eye 149 are so arranged that an ordinary switch stick may be used to hoist the arc-breaking device into position when the switch is vertical so that its lower end can seat in the socket. If the switch is in a position other than vertical,` the switch stick can be placed in the eye 150 which balances the arc-breaking device in a horizontal position so as to be inserted in a socket of a vertically located switch. After the device is positioned in the socket in this manner, the switch stick is removed from the eye 149 or the eye 150 and inserted in the eye 138. A pull on the latch lever by using the switch stick will move the latching device 130 into latching position with the -rib 146 of the contact housing 142 thereby locking the arc-breaking device 125 in iixed position within the socket 119 of the fitting 109. The rib 146 is so located on the contact housing 142 as to properly position a trip arm 151 on the arc-breaking device'125 to be engaged by a lug 153 on the contact arm 29 (see FIG. 2). Thuis, as the arm 29"is `rotated to disengage its paddle shaped end 36 from the fixed contacts, the lug 153 in turn assumes a position to be received between the spring contacts 155 and 156 within the fork-shaped opening 151a of the trip arm 151. Spring contacts 155 and 156 are so dimensioned that the lug 153 is snugly engaged forming the electrical connection between the movable contact arm 29 and the forked opening 151a of the trip arm 151.

As will be later explained, the arc-breaking device 125 has separable contacts which complete the circuit established with the lug 153 inthe contact arm 151 to the contact housing 142 within the socket l119 and, thence, to the bracket 12 for the fixed contacts of the switch. As soon as the lug 153 makesrm engagement during the switch opening movement, the second shunt circuit, heretofore mentioned, is thereby completed from the arm 29, lug 153, trip arm 151, arc-breaking device 125, to contact housing 142, socket 119 and to the bracket `12 carrying the xed contacts. The lug 153 and the' arc-breaking device 125 are so positioned by the fitting 109 that a firm' contact is established through the shunt circuit before the pin 95 leaves the contacts 100 and 101. Of course, the contact between arm 29 and fixed

contacts

24 and 26 has long since opened when this occurs, so that the current is being shunted throughl the pin 95 to the stationary contacts 100 and 101 before the second shunt contact is completed between the lug 153 and the trip arm 151. Y

. Enough has been said so far so that it will be quite apparent that by the use of an ordinary switch stick, the latch 130V can be operated to secure or release the arcbreaking device 125. The same stick, if desired, can be then used toengage either the eye 149 or the eye 150 to lift an arc-breaking device into or out of the socket. There is no circuit through the arc-breaking device until theswitch has opened far enough to engage the lug 15.3 in the trip arm 151. On the other hand, if the switch is fully open, there is no circuit which is closed through the arc-breaking device because the contacts therein would normally be open. In either case, this has inherent advantages obvious to those skilled in the art. has been said so far it will become now obvious that since the switch structure itself and the fitting 109 are detachably connected and that the arc-breaking device 125 is likewise detachably connected with the fitting, the switch maybe sold independently of the tting, the fitting independently of the switch or arc-breaking device, and-the latter independent of the others so that the instant needs of the purchaser of electrical equipment can .be satisfied by the purchase or" the desired parts. If at irst, but one o r two are purchased, he can add to these parts so as to have the complete combination.

Arc-Breaking Device 159 in which is a vent opening 161. The exhaust tube is preferably formed of ber glass laminate with a lining of acrylic resin, and the vent cap 159 is secured to the lower end thereof by a suitable cement iilling 157 in the interior annular groove 158, as shown in FIGS. 6 and 8. Between the vent cap 159 and lower end of the exhaust tube 140 is a sealing washer 160 which also performs the function of a valve seat as will be lated pointed out.

The contact housing 142 is secured to the upper'end of the exhaust tube 140 by cement 162 iilling the intemal annular groove 163 in the contact housing. The upper endof the contact housing 142 in turn is secured to the main barrel 141 by cement 165 filling the internal annular groove 166 in the upper end of the contact housing. The upper end of the exhaust 140 and the lower end of Vthe main housing 141 are spaced apart within the contact housing 142, and within this annular space are a pair of

brushes

168 and 169 with arcuate contact faces. With reference to FIG. 7, the brushes are in turn held in straddling relation clamped to the outside of the contact 170 by a resilient conducting metal U-shaped spring 172 with its ends riveted to each brush. This spring in turn is riveted or otherwise secured to the inner wall ofv the contact housing 142. The

brushes

168 and 169 are preferably tungsten-silver contacts. Between these brushes and the end of the main barrel 141 are a pair of

washers

173 and 174 which form a valve means with a gas restriction, the function of which will be later described.

The opposite end of the main barrel 141 is secured in a contact housing part of an actuating housing 185. This actuating housing contains a load and fire mechanism. The upper contact housing 180 is secured to the end of the main barrel 141 by cement 1813 iilling the internal annular groove 184. The mainbarrel 141 is also constructed of ber glass laminate lined with acrylic resin, and its upper end terminates within the contact housing 180 but spaced from an annular iiange 186 therein. In this space is disposed a pair of

brushes

190 and 191 which are constructed in the same manner as the

brushes

168 and 169.

Brushes

190, 191 are preferably of tungsten-silver and interconnected by a spring mounting which is in turn riveted to the inner wall of the contact housing 180. This spring holds the brushes irmly in engagement with a contact 195, the same as spring 172 holds

brushes

168 and 169 on Contact 170.

One wall of the actuating housing has a hollow boss with bushings to form a suitable bearing for stub From what shaft 193. One end of shaft 193 is xed within the trip arm 151v and is rotated thereby. The end of the stub shaft 193 within the actuating housingv185 is fixed' within an aperture in lever 197 so that lever 197 swings with the trip arm 151. As the lever 197 swings, it carries with it a spring reloader lever 199 to which it is pivoted at 200 by a pin. The connection between arm 197 and lever 199 is substantially intermediate the hooked end 202 at one end of the lever 199 and the opposite end of the lever which carries a pin 204. The pin 204 rides in grooves 205 and 205' in opposite sides of housing 185 as the arm 197 swings from one extreme position to another. The pin 204 is retained in the groove 205 and in a similar groove 205 on the opposite side of the housing. Inside the actuating housing 185 is a trip latch 207 carried on a pivot pin 208 to whichk it is xed. The pin is received in a suitable socket in onel side of the housing 185 and retained in the socket by the opposite side of the housing. The pin 208 in turn carries a spring anchor pin 210 to which one end of the latch spring 211 is connected. The opposite end of the latch spring 211 is anchored around pin 204. This spring normally biases the trip latch in a clockwise direction, and it is moved against spring pressure by the action of thev latch release 213, which, as it rotates in a clockwise direction, engages a trip pin 214 anchored in the trip latch pivot pin 208. The engagement of the latch release 213 with the trip pin 214 causes the latch to rotate in a counterclockwise direction or into its released position from its latched position. vIn its latched position, however, it engages beneath a shoulder of a head 216 which is slidable within a slotted sleeve 217.

Latch spring 211 has a dual function in this described construction. It holds the latch and also is the operating force in a spring powered snap action toggle formed by the pivoted connection of lever 197 to spring reloader lever 199.

The head 216 carries av pin 219 projecting through slots in the sleeve 217 into engagement with the hooked ends 202 of the spring reloader lever 199. The tube 217 is also slotted at 218 so as to allow the end of the trip latch 207 to engage beneath the head 216. This sleeve terminates in a socket 220 at one end of the housing 185, the other end of the sleeve 217 projects through the opposite side of the housing 185 and is enclosed and secured in position by a cap 222 carrying the eye 149. Cap 222 is suitably flanged and has apertures in the flange for receiving the attaching screws 223 which secure the cap firmly to the side of the housing.y Within the housing is a firing spring 225 compressed between the top surface of the head 216 and the end of the cap 222.

The head 216 is formed on one end of a nylon trailer 230 which has a threaded socket receiving a threaded end of a bronze spacer rod 227 extending to and through contact 195 to contact 170. Each of the

contacts

195 and 170 are suitably secured by internal threads to the threaded exterior of bronze spacer rod 227. Surrounding the bronze spacer rod 227 between the

contacts

170 and 195 is an acrylic resin sleeve 231. The lower face of the contact 170 acts as a valve to close the vent 156 when it moves to the position in contact with the washer 160 under the influence of the spring 225. The cavity in the housing 185 is enclosed by a plate 235 and secured in position by

suitable'screws

236, 237, 238 and 239.

The housing 185 is electricallyy connected to arm 151 by a brushY 240 of bronze mounted on the housing by a screw, as shown in FIG. 8. This brush bypasses the electric v path from the actuating mechanism which is from arm 151, brush 240, contact housing part 180, brushes 190, 191, contact 195, spacer rod 227, contact 170, brushes 168,169 and contact housing 142.

Fromthe construction of the arc-break device, so far described, it will be apparent that when the lug 153 forms apositive contact with the spring contacts 155 and 156 of the trip arm 151, a circuit is completed when the arc-break contacts are closed. Thisl circuit includes the

movable contacts

170 and 195 in series relation. As the lug 153 is moved in a counterclockwise direction `by the contact arm 29 of the switch, the trip arm 1751 moves in a clockwise direction. As the trip lever 151 continues to rotate in a clockwise direction, the hooked endV 202 of the spring reloader lever 199 is withdrawn toward and releasing head 216. Spring 225 then drives the head and plunger assembly toward the opposite side of the casing where pin 217 is positioned to be engaged by the end of the hook 202 in spring reloader lever 199. When the trip lever 151 is released from the lug 153, spring 211 will index the position of trip arm 151 to again engage with lug 153, after the switch is opened or after it has closed. Since the head 216 and

contactsY

170 and 195 are interconnected mechanically by being part of a plunger assembly, the contacts are separated from their respective brush connections to break the shunt circuit. The fact that there are two of these contacts-means that the effective gap will be developed twice as fast as with a single Contact, and this multiples the rapid action produced mechanically by the spring 225. As

contacts

170 and 195 separate from their respective pairs of brushes, a pair of arcs will developv between theedges of the brushes `adjacent the contacts as they recede in a direction away from these brushes (see FIG. 9) and move rapidly to a fully displaced position as shown inl FIG. 10. As shown in FIG. l0,`

the arcs developed will be rapidly elongated into the narrow space between the acrylic resin sleeve of the inner surface of the barrel 141 and the outer surface of the nylon trailer sleeve 230. At the opposite end,V the arc willbe drawn between the inner surface of the exhaust tube and the outer surface of the acrylic resin sleeve 231. The arc formation will develop a gas pressure due to heating of the acrylic resin linings in the barrel and on the trailer and sleeve. This produces in turn a gas pressure which will tend to expand both ways from the contact 195 and both waysr from the contact 170. However, the gas pressure developed about the contact and about the contact 195 will actuatef the

washers

173 and 192 respectively so as to force them to act as valve` means causing the gas to blow in the direction of the vent 161. The gas pressure developed near the

contacts

170 and 195 will be restricted in its passage by the restricted clearance between the

washers

173 and 192 and the plunger assembly. This causes the gases rst to flow in a direction from the housing toward the vent 161. Ordinarily, turbulence created by the passage of gases will be enough to suppress the arcs developing about the

contacts

170 and 195 long before the contact 170 seals the vent opening 161 by seating on the washer 160. If either arc is blown out, the circuit is broken because they are in series. is the operational life of these devices limited by the total gap produced between the contacts and' brushes, but also by the fact that carbon deposits accumulate afterl each operation. These carbon deposits form a path for electrical leakage withiny the barrel and within the exhaust tube between each contact and its set of brushes. Of course, when this happens, the useful life of the arc-breaking device is terminated. This is true simply because the device can no longer break the circuit completely. Generally, this occurs withoutV warning and causes the arc to be restruck. To prevent this from happening without warning, kthe instant device is constructed so that if both arcs continue after contact 170 has seated and vent 161 is closed, the pressure build- However, not onlyv up of gases will increase very rapidly and reverse its direction of flow passing the restriction of the

washers

173 and 174 and blasting up the barrel past the restriction of washers 192 into the housing 185. The fact that the gases begin to escape from the housing 185 through vent holes, such as 250 in its side walls, will indicate what has happened to the lineman, but, in addition, this high pressure due to the closing of the vent will produce extremely high turbulence in the exhaust tube and barrel in a direction to blow out the arcs and, therefore, extinguish the arcs. The trip angle for the latch 207 will be reached when the contact arm 29 has attained the angular position B about the hinge. The distance from A to B indicates approximately the separation which has been obtained between the pin 9S and its stationary contacts 100 and 101 when the arcs are extinguished.

As the switch arm 29 is moved from its fully opened position toward its closed position, lug 153 will again engage the fork and contacts in the trip arm 151 and begin to rotate the arm in a counterclockwise direction. This will rotate the arm 197 in a similar direction and move the hooked end 202 and head 216 by engagement of pin 217 toward a position beyond position A in which trip latch 207 can engage beneath the shoulder on the head 216. At the time arm 29 reaches to position A, however, pin 95 again re-enters between its contacts 100 and 101 closing the shunt circuit around the switch contacts. Beyond the angle A of arm 29,

contacts

170 and 195 again close and latch 207 snaps under head 216. As the switch arm 29 continues to close, lug 153 will leave the trip lever and the shunt circuit will be continued solely by contact of pin 95 until the switch is fully closed.

Changes in and modifications of the construction described may be made without departing from the spirit of my invention or sacrificing its advantages.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

l. In an electric switch having a relatively fixed contact and a movable contact engageable with and disengageable from said fixed contact to connect and disconnect a heavy electric load respectively, the combination of means for suppressing the arc formed during switch operation comprising separate means for forming circuits through said movable contact in shunt relation with said fixed and movable contacts operated sequentially to open during movement of said movable contact from said fixed contact to transfer the current path from said switch to one of said shunt circuits and from one of said shunt circuits to another without interruption, a circuit interrupter of the arc suppressing type in said shunt circuit which is last to open, and means to operate said circuit interrupter in response to further opening movement'of said movable contact to finally break the circuit between contacts of said switch before disengagement of said means in the shunt circuit last to open.

2. In an electric switch mechanism having a relatively fixed contact and a movable contact engageable with and disengageable from said fixed contact to connect and disconnect a heavy electric load respectively, the combination of means forming a part of said switch mechanism for suppressing the arm formed during switch operation comprising separate means for forming circuits through said movable contact in shunt relation with said fixed and movable contacts operated sequentially to open during movement of said movable contact to open said switch to thereby transfer the current path from said switch to one of said shunt circuits and from one of said shunt circuits to another without interruption, a circuit interrupter of the arc suppressing type in said shunt circuit which is last to open, and means to operate said circuit interrupter in response to further opening movement of said movable contact to finally break the circuit between contacts of said switch before disengagement of said means in the shunt circuit last to open.

3. In an electric switch mechanism having a relatively fixed contact and a movable contact engageable with and disengageable from said fixed contact to connect and disconnect a heavy electric load through said switch respectively, the combination of means forming a part of said switch mechanism for suppressing the arc formed during switch operation comprising separate means for forming` circuits through said movable contact in shunt relation with said fixed and movable contacts operated sequentially to close during movement of said movable Contact to close said switch to thereby transfer the current path from one or said shunt circuits to another and then to the switch Without interruption, a circuit interrupter of the arc suppressing type in said shunt circuit which is last to open, and means to operate said circuit interrupter in response to further opening movement of said movable contact to finally break the circuit between contacts of said switch before disengagement of said means in the shunt circuit last to open.

4. In an electric switch mechanism having a relatively fixed contact and a relatively movable contact engageable with and disengageable from said fixed contact to connect and disconnect a heavy electric load respectively, the combination of means forming a part of said switch mechanisrn for suppressing the arm formed during switch operation comprising separate means on said switch for forming circuits through said movable contact in shunt relation to said fixed and movable switch contacts, separately operable in uninterruptable sequence during opening movement of said movable contact after said contacts have separated to transfer the current path from one of said shunt circuits to the other, and an arc suppressing device in said other shunt circuit actuated by said movable contact.

5. In an electric switch mechanism having a relatively fixed contact and a relatively movable contact engageable with and disengageable from said fixed contact to connect and disconnect a heavy electric load respectively, the combination of an arc suppressing device removably mounted adjacent to said contacts on said switch and electrically connected through the mounting to one of said switch contacts and comprising a movable trip device engaged oy the other of said switch contacts after said switch is opened to form an electrical connection between said other switch contact and said trip device only during engagement therebetween but not when said switch is fully open or partly or fully closed, and separable contacts in said arc suppressing device electrically connected respectively with said one switch contact and said movable trip device to complete a shunt circuit between said switch contacts only when said movable trip device engages the other of said switch contacts so that while the switch is in service the arc suppressing device may be replaced while the switch is either fully opened or closed.

6. In an arc suppressing device for an electric switch having a housing with a barrel, a fixed contact in said housing, a plunger assembly movable in said barrel and defining a restricted space with said barrel, a movable contact on said plunger assembly movable with said plunger assembly from a position in contact with said fixed contact away from the fixed contact into the barrel, the combination of means for biasing said contacts apart, a latch resisting relative Contact movement, an actuator, an over-center toggle with a spring actuated snap action and carrying a latch release and connected to and operated by said actuator to a dead center position and beyond dead center position by the spring action to then release said latch by impact of said latch release with said latch, and means on said toggle and on said plunger engaged by reverse movement of said actuator for repositioning said plunger to its latched position.

7. In an arc suppressing device for an electric switch having a housing with a barrel and a vent in the barrel, a fixed contact in said housing, a plunger assembly movable in the barrel and defining a restricted gas passage 1i with said barrel, a movable contact on said plunger assembly and movable with said plunger assembly from a position in Contact with the fixed contact away from the xed Contact into said barrel to draw an arc into the restricted gas passage and generate a gas pressure, the improvement comprising a flow restricting valve means in said barrel closed by gas pressure generated by the arc as the contacts open 'to cause a gas flow in one direction towards the Vent and means actuated by continued movement of said plunger assembly for closing the vent and reversing the gas ow direction.

8. In an arc suppressing device for an electric switch having a housing with a barrel and a vent in thebarrel, a fixed contac't in said housing, a plunger assembly mov'- able in the barrel and defining a restricted gas passage with said barrel, a movable contact on said plunger assembly and movable with the lplunger assembly from a positon in contact with the xed contact away from the fixed` contact into the barrel to draw an arc into the restricted gas passage and generate a gas pressure, the improvement comprising a flow restricting valve means located in said housing on the opposite side of Said contacts from the vent in said barrel and arranged to close.

by gas pressure generated by the arc as the contacts open to cause a gas flow in one direction towards the vent and means actuated by continued movement of said plunger assembly for closing the vent and reversing the gas iiow direction toward the valve means and the contacts.

9. In an arc suppressing device for an electric switch having a housing with a barrel and a vent, a fixed contact in said housing, a plunger assembly movable in the barrel and defining a restricted gas passage with the barrel, a movable contact on said plunger assembly and movable With the plunger assembly from a position in contact with the fixed Contact away from 'the xed contact and into the barrel to draw an arc into the restricted gas passage and generate a gas pressure, the improvement` comprising a ow restricting valve means in said barrel on opposite sides ofsaid contacts one of which is closed by gas pressure generated by the arc as the contacts open to cause a gas flow in one direction toward the vent and the other of which is opened by gas pressure, and means actuated by continued movement of said plunger assembly for closing the vent and reversing the gas ow direction so as to close both valve means and build up a high pressure in the barrel.

10. In an arc suppressing device for an electric switch having a housing with a barrel and a vent, a pair of 12B spaced apart ixed contacts in the housing at opposite ends of the barrel, a plunger assembly movable in the barrel and deining a restricted gas passage with said barrel, a pair of spaced 4apart electrically connected movable contacts on said plunger assembly and movable with the plunger assembly from a position engaged with said xed contacts away from said fixed contacts into the barrel to draw an arc into the restricted gas passage and generate a gas pressure, the improvement comprising a flow restricting valve means in said barrel located on the opposite sides of all of said contacts from the vent and ar-` ranged to be closed by gas pressure generated by the arc as the contacts open to cause a gas flow in one direction towards the vent and means actuated by continued move,-

ment of said plunger assembly for closing the vent and reversing the gas flow direction to increase the pressure in said housing and barrel.

11. In an arc suppressing device for an electric switch having a housing with a barrel and a vent, a pair of xed spaced apart contacts in said housing and barrel, a plunger assembly movable in the barrel and deining a restricted gas passage with the barrel, a pair of spaced apart electrically interconnected movable contacts on said plunger assembly and movable with said plunger assembly from a position engaging with said xed contacts respectively away from said xed contacts into said barrel to draw an arc into the restrictedgas passage and generate a gas pressure, the improvement comprising a W v restricting valve means in said barrel on the opposite side of said xed contacts from the vent and arranged to be closed by gas pressure generated by the arc as the contacts open to cause a gas flow in one direction towards the ven't and means actuated by continued movement of said plunger assembly for closing the vents and reversing the gas ow direction to increase the pressure in the barrel.

References Cited inthe le of this patent UNITED STATES PATENTS 1,556,829 Wyman Oct. 13, 1925 2,272,717 Ludwig et al Feb. 10, 1942 2,621,271 Lindell Dec. 9, 1952 2,658,977 Hoye Nov. 10, 1953 2,824,935 Haslam Feb. 25, 1958 2,824,936 Huttinger Feb. 25, 1958 2,838,636 Schwager June 10, 1958 2,897,323 Krase July 28, 1959 2,955,181 Luehring Oct. 4, 1960 `UNITED STATES PATENT OFFICE vCERTIFICATE 0F CORRECTION Peteur, No. 3144,53e 4 'August 11, 1964 Renew P Bridges et e1 C It is hereby certified tbet errer eppeere in Jthe above numbered petent requiring correction and that the said Letters Patent should read as corrected below.

Column 4 line 54V for "fititnj'" reed e fitting me; :olumn 6 line 35 for "lated" read me later me; column 'Tv line lv for The read =-v This es; Column 9 line 62v for "arm" read are column lO line 12I for "or" read Signed and sealed this 19th day of January 1965.,

EAL)

lest:

NES-T W. SWIDEIR- EDWARD J. BRENNER testing Officer A Commissionerof Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3144,53e 'August 11, 1964 110113101 Pa Bridges et e1o 1t ie hereby certified that errer eppeere in the ebeve metered petent requiring correction and that the said Letters Patent should read as corrected below Signed and sealed this 19th day of January 1965e EAL) Ltest:

RNEST W. SWIDER EDWARD J. BRENNER ltesting Officer Commissioner of Patents

Claims

1. IN AN ELECTRIC SWITCH HAVING A RELATIVELY FIXED CONTACT AND A MOVABLE CONTACT ENGAGEABLE WITH AND DISENGAGEABLE FROM SAID FIXED CONTACT TO CONNECT AND DISCONNECT A HEAVY ELECTRIC LOAD RESPECTIVELY, THE COMBINATION OF MEANS FOR SUPPRESSING THE ARC FORMED DURING SWITCH OPERATION COMPRISING SEPARATE MEANS FOR FORMING CIRCUITS THROUGH SAID MOVABLE CONTACT IN SHUNT RELATION WITH SAID FIXED AND MOVABLE CONTACTS OPERATED SEQUENTIALLY TO OPEN DURING MOVEMENT OF SAID MOVABLE CONTACT FROM SAID FIXED CONTACT TO TRANSFER THE CURRENT PATH FROM SAID SWITCH TO ONE OF SAID SHUNT CIRCUITS AND FROM ONE OF SAID SHUNT CIRCUITS TO ANOTHER WITHOUT INTERRUPTION, A CIRCUIT INTERRUPTER OF THE ARC SUPPRESSING TYPE IN SAID SHUNT CIRCUIT WHICH IS LAST TO OPEN, AND MEANS TO OPERATE SAID CIRCUIT INTERRUPTER IN RESPONSE TO FURTHER OPENING MOVEMENT OF SAID MOVABLE CONTACT TO FINALLY BREAK THE CIRCUIT BETWEEN CONTACTS OF SAID SWITCH BEFORE DISENAGEMENT OF SAID MEANS IN THE SHUNT CIRCUIT LAST TO OPEN.