US2923799A

US2923799A - Interrupter switch

Info

Publication number: US2923799A
Application number: US679201A
Authority: US
Inventors: Polgov Nicholas; Glenn R Runke
Original assignee: HK Porter Co Inc
Current assignee: HK Porter Co Inc
Priority date: 1957-08-20
Filing date: 1957-08-20
Publication date: 1960-02-02
Anticipated expiration: 1977-02-02

Description

Feb. 2, 1960 N. POLGOV ETAL 2,923,799

INTERRUPTER SWITCH Filed Aug. 20, 1957 2 Sheets-Sheet 1 INVENTORS y; PM W .ij rae Y B u bah...

Feb. 2, 1960 N. POLGOV ETAL 2,923,799

INTERRUPTER SWITCH Filed Aug. 20, 1957 2 heets-Sheet 2 BY BMW, I

Baa

11w NTORS.

United States Patent INTERRUPTER SWITCH Nicholas Polgov, Chicago, Ill., and Glenn R. Runke, Elkridge, Md., assignors to H. K. Porter Company (Delaware), Chicago, 111., a corporation of Delaware Application August 20, 1957, Serial No. 679,201

Claims. (Cl. 200-146) The present invention relates to switches for interrupting the flow of current in electric power transmission systems and particularly, to improvements in switches of the general character.

In high tension electric transmission systems, current fiow cannot normally be stopped by the simple expedient of separation of a pair of switch contacts at normal speed for the reason that, as the contacts are separated, an arc strikes between the contacts due to the high voltage of the system, which are maintains a path of current flow through the system. Prevention or breaking of this are is commonly referred to as current interruption and may be accomplished in various manners depending on the rating of the system, for example, by high speed separation of the contacts and/or by fluid extinction of the arc. One type of interrupter that has proven highly successful in the art comprises a movable contact carrying rod that is reciprocated at high speed within a generally tubular chamber closely surrounding the rod and constructed of material that evolves an arc extinguishing gas upon exposure to and decomposition by an electric arc.

It is the object of the present invention to provide an improved interrupter switch of this type.

In particular, it is an object of the invention to provide improved means for effecting rapid separation of the switch contacts in interrupters of the general type.

A more specific object is the provision of improved actuating means for the reciprocable contact carrying rod' which means requires only a relatively small, slow input movement to effect a relatively long stroke of the rod at exceedingly high speed, and which means translates slow arcuate input movement to high speed purely linear movement of the rod.

Another object of the invention is the provision of improved gas evolving chamber means for switches of this type.

A further object: of the invention is to provide improved means insuring uniform wear or erosion of the contacts and uniform decomposition or erosion of the gas evolving material.

A still further object of the invention is the provision of an improved interrupter switch of compact economical construction facilitating mounting and actuation of the same in a highly simplified manner.

These and other objects and advantages of the invention will become apparent in the following detailed description of a preferred embodiment of the invention.

Now, in order to acquaint those skilled in the art with the manner of making and using the improved interrupter switch of our invention, we shall describe, in connection with the accompanying drawings, a preferred embodiment of our invention and a preferred manner of making the same.

In the drawings:

Figure 1 is a side elevation of a disconnecting switch equipped with our improved interrupter switch and showing the simplified manner in which the interrupter is mounted on and actuated by the disconnect switch;

Figure 2 is a perspective view, partly in section, of our improved interrupter, the view showing the cover plate for the pull rod actuating means removed to reveal said means;

Figure 3 is a side view, partly in section and partly in elevation, of the interrupter;

Figure 4 is a fragmentary view, partly in section, taken generally from the left side of Figure 3 and showing the pull rod actuating means; and

Figure 5 is a sectional view taken substantially on line 55 of Figure 3 showing the means for insuring uniform erosion of the contacts and gas evolving material.

With reference to Figure 1, wherein we have shown our interrupter switch I mounted for use on and in conjunction With a disconnecting switch D, it is to be observed that in high tension electric systems separate switches are required for performance of the function of, first, carrying current and disconnecting or isolating part of .the circuit, and second, making and breaking the circuit. The reason for this is that the instrumentality for .special instrumentality, an interrupter, for making and breaking the circuit.

The disconnect switch D illustrated in Figure 1 is of the type shown and described in the patent to Fjellstedt et al., No. 2,527,924. The switch comprises, generally, a base 10 carrying three

insulators

12, 14 and 16, the outboard ones of which are stationary and carry

terminal lugs

18 and 20 and the center one of which is rotatable. The left hand insulator 12 carries the stationary contact 22 of the switch and the right hand insulator carries the frame 24 of the switch operating mechanism. This mechanism includes a blade guide 26 pivotally mounted on the frame 24, a blade carriage 28 rotatable in the guide, and a crank arm 30 secured to theupper end of the rotatable insulator 14, the arm 30 and carriage 28 being rotatably connected at 32 along an axis extending at an angle of approximately 45 to the axis of the insulator 14. The switch blade, which is indicated at 34, is secured adjacent one end in the carriage 28 and extends therefrom to the stationary contact 22, the blade at its outer end being flattened in the form of a beaver tail for purposes of high pressure engagement in the contact. As is conventional, the blade 34 and the contact 22 carry cooperable arcing horns 36 and 38, respectively.

To eifect operation of the disconnect switch, the insulator 14 is rotated about its own axis to impart movement to the switch blade 34. Upon initial rotation of the insulator the blade 34 is subjected primarily to rotation around its own axis to relieve its high pressure engagement in the contact 22, whereafter the blade, while continuing to rotate, is swung in an arc of approximately about the pivot axis of the guide 26 to a substantially vertical switch open position. During such movement, the insulator 14 is rotated in an are somewhat greater than 90 and the blade is both rotated about its own axis 90 and swung in an arc of approximately 90". Upon reverse rotation of the insulator, the blade is returned'to its switch closed position in reverse order.

According to the present invention, the interrupter I comprises a column adapted particularly to be mounted in an upright position on the stationary contact of a disconnecting switch, the interrupter adjacent its upper end including an oscillatable actuator arm 40 adapted to be engaged and moved by the blade 34 of the disconnect switch whereby interruption of current flow and discon-- nection of the circuit may be effected simply by operating r is rotated in the upward direction until the blade 34 is sufi'iciently separated from the contact 22 to prevent striking of an arc therebetween. At approximately this point, the interrupter is actuated to break the circuit in a manner to be described. Thereafter, due to the differences in length and relative location of the pivot axes of the blade 34 and arm 40, the actuator arm 40 is released from the horn 36 as the blade'34 continues to move toward full open position. The arm 40 is then returned automatically to a predetermined position in the arcuate pathof movement of the horn 36.

To reclose the circuit, the disconnect switch is operated to move the blade 34 toward closed position. During closing movement, the horn 36 on the blade again engages the actuator arm 40 of the interrupter to move the same downwardly. As the blade 34 approaches the contact 22, the interrupter is actuated to remake the previously described circuit. the actuator arm 40 substantially until the horn 38 is reengaged, whereafter the arm 40 may be released for automatic return to the position shown in Figure 1, the circuit thenb'eing completed directly through the blade 34 and contact 22.

' The interrupter of the invention is shown in detail in Figures 2 and 5 and is comprised essentially of three components, namely, arcing chamber means 42, pull rod means 44 reciprocable in the arcing chamber, and actuating means 46 for the pull rod.

The arcing chamber means 42 includes as its principal element an upright tubular insulator 5t? of conventional form. In its upper portion, the insulator houses a tubular liner 52, which may if desired be constructed-in any conventional form of any conventional material capable of evolving an arc extinguishing gas in the presence of an electrical arc. However, according to our invention, the liner is preferably comprised of inner and outer tubular parts, the inner one of which is preferably formed of polytetrafluoroethylene or equivalent materials, and the outer one of which is formed of a material such as Bakelite or porcelain which is capagle both of rigidifying or bracing the inner tube and serving as a structural element of assembly. The outer tubular part is threaded at its upper and lower ends and at its lower end is secured to the upper end of a tubular metallic conductor 54. The

counterbored for the reception of an annular stationary contact 56 which, due to the threaded attachment of the outer liner tube and the conductor, is confined between the inner liner tube and the conductor in electrically conductive relation to the latter. At its lower end, the con-. ductor protrudes below the lower end of the insulator 50 to accommodate attachment thereto, by means of cooperating screw threads, of a metallic tubular fitting 58. The fitting 58 includes a generally cup-shaped annular portion within which the lower end of the insulator is received, the insulator beingsealed to the fitting by means of a cement or like fill 60. On the exterior surface thereof, the fitting 53 includes a plurality of radially extending mount- The horn 36 remains in contact-with ing lugs 62 by means of which the interrupter switch maybe mounted in upright vertical position on the stationary conductor 54 is of thickness slightly less than the combined thickness of the liner tubes and adjacent its upper end is" contact structure 22 of the disconnect switch D and by.

means of which the stationary contact 56 of the interrupter is electrically connected to the stationary contact of the disconnect switch.

' The arcing chamber defined by the above described means comprises a vertical cylindrical bore through the inner liner tube, the stationary contact and the tubular conductor, the bore being of slightly larger diameter below the contact than above. At. the lower end of the chamber,

fluid ingress and egress thereto is restricted by means of a gas condenser 64 depending from the fitting 58. The condenser comprises a tubular stem 66 having a perforate side wall andan upper flange secured to the fitting, a cupshaped case 68 secured to the stem by an axial bolt 70 and a plurality of concentric perforated walls '72 within the case, the perforations in the stem 66 and the walls 72 establishing restricted communication between the arcing chamber and a plurality of outlet ports 74 provided adjacent the marginal edge of the bottom wall of the case 68. As will appear more fully hereinafter, the upper end of the insulator 50 is sealed, so that the ports '74 constitute the sole path of communication between the interior of the interrupter and atmosphere. Due to the construction and disposition of the condenser, liquids cannot enter into the arcing chamber, yet the chamber is constantly vented to atmosphere to accommodate restricted release of arc extinguishing gas upon occurrence of an electrical arc and to equalize internal and external pressures.

The pull rod means or assembly 44 com-prises a metallic conductive rod 76 extending axially into the upper end of the arcingchamber, the rod at its upper end i carrying a clevis '78-. Adjacent its lower end, the rod 76 carries an annular contact Stl which is relatively long in relation to the contact 56 and which is counterbored at its upper side. The contact St is of an outer diameter equal substantially to the inner diameter of the stationary con-- tact 56 and liner 52 and is mounted on the rod 7 6 in such position as to engage the contact 56 in the switch closed position of the pull rod. Between the clevis 78 and the contact 80, the rod 76 carries a guard sleeve 82 which is preferably formed of polytetrafluoroethylene or equivalentmaterials, the sleeve being of a diameter to fit within the counterbore of the contact 80 at its lower end and being spaced from the walls of the arcing chamber throughoutits length. Below the contact 30, the rod 76 has threaded thereto a follower 84, which like the liner 52 is formed of a gas evolving material, in the preferred embodiment of this invention of polytetrafiuoroethylene. The follower 84 encloses the portion of the rod 76 below the contact 80 and is of a diameter equal substantially to that of the contact. The follower is of such length relative to the arcing chamber and the stroke of the pull rod that the lower end thereof moves from a position within the condenser 64- to a position substantially abreast of the stationary contact 56 in moving from switch closed to switch open positions, as indicated, respectively, by the points X and Y."

At its lower end, the follower 34 includes a conical cam surface 86 for a purpose to be described.

In the completed assembly of the arcing chamber and pull rod means, the pull rod and its components are reciprocable axially of the chamber. In switch closed position, as shown in Figure 3, the contacts 56 and 80 are in engagement, the liner 52 is spaced from the guard sleeve 82 and the follower 84 is'spaced from the tubular conductor 54. Upon occurrence of switch opening movement the contacts are separated and the follower 84 is moved into. the liner 52 between which there is very little clearance. The electrical are normally striking between the contacts on switch opening movement is thereby confined between two substantially engaging non-conductive elements, whereby the arc is smothered. Moreposes and evolves an arc extinguishing gas in the presence of an electrical arc, thereby promptly to quench the arc and insure interruption of currentflow. In this latter respect, the condenser 64 so retards exhaust discharge of the arc extinguishing gas as to insure prompt extinction of the are, yet the condenser, by venting the arcing chamber to atmosphere, prevents the occurrence of excessive pressure within the chamber.

According to the present invention, we have discovered that polytetrafiuoroethylene, commercially available under the trade name Teflon, is an optimum material from which to fabricate the follower and liner. In the first instance, the material meets the primary requirements of these components in that it is a good insulator, decomposes in the presence of an electrical arc to a vapor which leaves no carbonized path and which, judging from our tests, assists in quenching the arc and, both in its solid and gaseous states, is non-flamable. Second, the material is readily molded and/or machined to any desired configuration, so that fabrication and assembly of the liner and follower are greatly facilitated. Third, and this is in direct contrast to gas evolving materials previously employed in the art, the material has zero water absorption and is dimensionally stable throughout the full range of atmospheric conditions encountered in outdoor use of the switch. This is particularly important in view of the dimensional tolerances necessarily imposed on the subject components and facilitates fabrication of each as a unitary element as contrasted to the multi-part fabrication heretofore widely adopted in the art. Finally, the physical and electrical properties of the liner and follower can be modified by addition to the polytetrafluoroethylene prior to'molding of various additives such as asbestos, glass fiber, coke flour, etc., whereby the reaction of the said components to the electrical arc may be varied as required for special applications.

The are striking between the stationary and movable contacts of an interrupter switch on switch opening movement will strike along the path of least resistance, which has led heretofore to the arc striking along the same path on successive operations of the switch whereby each contact has been eroded at only. one point and the gas evolving materials have been decomposed and eroded only along a single longitudinal path. After a certain amount of erosion, i.e., after a given number of switch operations, it has been necessary to replace the contacts and the gas evolving materials, even though the majority of the surface areas of these members had not in any way been affected.

It is an object of the present invention to increase the useful life of the contacts and gas evolving materials in interrupter switches by distributing the wear and erosion over substantially the full area of these members, whereby switch operations may be multiplied many times over the number previously deemed practical before these members or materials need be replaced. To this end, we have incorporated in our interrupter a creeper spring 88 which is mounted for rotation about the axis of the pull rod in a cylindrical counterbore in the lower face of the fitting 58, the spring being retained in the counterbore by the stem of the condenser 64; The creeper spring 88 comprises a unitary leaf spring including a first portion 90 comprising a chord of the bore and terminating at its free end in an arcuate end portion slidably engaging the wall of the bore. At the other end of the first portion, the spring is arcuately curved for slidable engagement with the wall of the bore and includes a second portion 92 extending generally diametrically across the bore and intersecting the path of movement of the cam surface 86 provided at the free end of the pull rod follower 84. Actually, the portion 92 of the spring is offset slightly to the side of the axis of the pull rod adjacent the portion 90 of the spring to insure proper engagement of the cam surface 86 therewith. For this latter purpose, the spring portion 92 may also include a genmodating access thereto erally V-shaped central portion as shown in Figure 5. At its free end, the second portion 92 of the spring bears against the wall of the fitting and defines a fulcrum about which spring actuated movement of the spring takes place. For this purpose, the edge of the thin leaf stock bears against the fitting wall to provide a relatively high coefficient of friction therebetween. If desired, this edge of the spring may be sharpened.

In use, as the pull rod and its follower move from switch open to switch closed position, the cam surface 86 on the follower engages the portion 92 of the spring and exerts a'radially directed force thereon. Since the first portion 90 of the spring is substantially centered relative to this force, no movement is imparted to said portion and the second portion 92 of the spring is moved toward the first portion thereby moving the free edge of the portion 92 angularly in a clockwise direction as the spring is viewed in Figure 5. As thus stressed, the portion 92 of the creeper spring exerts a radial biasing force on the follower 84 and the pull rod carried contact so that upon subsequent switch opening movement of the pull rod, the electrical are striking between the contacts is induced to occur at a point diametrically opposite the point of force application of the creeper spring. As switch opening movement continues, subsequent to striking of the arc, the cam surface 86 of the follower 84 clears the creeper spring, whereupon the spring is re leased to assume its relatively relaxed position. In doing so, the spring is required to move about the fulcrum defined by the free edge of the second portion 92 thereof due to the relatively high frictional engagement of this edge with the wall of the bore. The portion 92 of the spring, due to the stressed condition thereof, moves about this fulcrum point toward its normal, substantially diametric position in the bore, thereby causing the first portion of the spring to slide angularly in the clockwise direction as the spring is viewed in Figure 5. Upon successive switch opening and closing movements, the creeper spring 88 is thus caused to index angularly about the axis of the pull rod, so that the spring exerts pressure on the pull rod from a different angle, i.e., on angularly spaced portions thereof, each time the switch is closed, the point of force application advancing circumferentially around the pull rod. Accordingly, the are striking between the two contacts on each opening movement of the pull rod is induced to occur at angularly spaced points around the entire circumference of the two contacts, thereby equalizing erosion of the contacts and the gas evolving materials over their full circumferences. Thus, the life of the switch components is appreciably increased.

In addition to smothering the arc and effecting extinction. of the same by gaseous products of decomposition, the switch of the invention effects interruption of current flow by virtue of high speed actuation of the pull rod. To insure interruption of current flow on switch opening movement, and to mitigate the occurrence of arcing upon switch closing movement, the pull rod is preferably actuated at high speed in both directions of its movement. To eifect these high speed movements, we provide an improved pull rod actuating means 4-6, The means is enclosed within a hollow casing 94 having a tubular fitting 96 at its lower edge, the fitting including an inverted cup-shaped portion receiving the upper end of the insulator and being sealed thereto by a cement or like fill 98. In its central portion, the fitting is threaded for attachment to the upper end of the outer member of the liner 52 and includes a portion bearing on the top of the inner member of the liner to complete the assembly of the arcing chamber. The casing 94 includes a removable side wall 100 accomfor purposes of assembly and servicing of the actuating mechanism, the side Wall 100 normally being affixed and sealed to the casing 94 to seal the arcing chamber from atmosphere at its upper end.

The pull rod actuating mechanism per se is mounted on abase plate 102 which is fixedly supported within the casing 94 in spaced parallel relation to the axis of" which an actuating shaft-106 is journaled, the shaft 106 extending transversely of the axis of the pull rod to the exterior of the casing. The casing includes a boss 198 rotatably supporting. the shaft and housingsealing means. for the shaft. To the exterior of the casing, the shaft is adapted for reception of the actuator arm 40 previously described, by means of which oscillatory actuating movement is imparted to the shaft. Within the casing, the shaft carries a first bracket 110 including a base portion disposed adjacent the boss 108 and an inwardly extending tab 112 disposed in spaced parallel relation to the axis of rotation of the shaft. Inwardly of the bracket 110, the shaft 106 is of reduced diameter and extends through and beyond the base plate 102. At its inner end, the shaft defines a rotatable support for the base portion of a second bracket 114, which bracket includes a tab 116 extending outwardly toward the base portionof the bracket 110, the tab 116 being disposed radially inward ofthe tab 112 and generally paralleling the same, the two tabs being of substantially the same width. Intermediate the base portions of the two brackets, a torsion spring 118 is disposed about the shaft 106, the spring including radially outwardly extending

end portions

120 and 122 engaging against the opposite sides of the

tabs

112 and 116 and normally centering the same on one another. In its normal condition,

the spring 118 is pre-stressed to insure this centering action.

The base portion of the inner or second bracket 114 includes a semicircular portion struck from the axis of the shaft 106 and of a radial extent to project beyond the apex portion of the base plate 102. The edge of this portion defines a cam surface 124 which terminates at its opposite ends in abrupt radial steps 1'26 and 128, respectively. At opposite sides of the bracket 114, the base plate 102 pivotally mounts a pair of

detent arms

130 and 132 respectively, each of which extends toward the cam surface 124 and adjacent its outer end carries a

roller

134 and 136, respectively, engaging against said surface, the two rollers being spaced less than 180 apart, preferably about 105 apart. Each detent arm at its outer end also includes a

cam surface

138 and 140, respectively, disposed in the path of movement of the tab 112 of the first bracket 110. A tension spring 142 extends between the roller shafts of the two detent arms to retain the same in engagement with the cam surface.

In use, the second or inner bracket 114- is oscillatable between two end positions andis adapted to be retained alternately in said positions by the

detent arms

130 and 132 which are adapted to engage alternately against the

radial steps

126 and 128, respectively, in the cam surface. Oscillation of the bracket 114 is effected at high speed by the torsion spring 118 in a manner to be described and is imparted by the bracket to the ,pull rod means 44 through a radial crank arm 144 on the bracket and a link 146. The link 146 is pivotally connected intermediate its ends to the crank arm 144 and at one end thereof carries a roller 148 which engages in the slot 104 in the base plate 102 and slidably guides the one end of said link in the slot. At its other end, the link is bent upwardly to the axis of the pull rod and is pivotally connected to the pull rod clevis 78. In this regard, it is to be observed that the entire actuating mechanism, except for the said other end of the link 146, is spaced to one side of the pull rod to accommodate movement of the pull rodpast the same.

In the two end positions of the bracket 114 and crank. armi144, the roller 148 on the link 146 engages substantially against the bottom of the slot 104 to retain thebracket, link. and pull rod against other than tolerable movement beyondthe respective end position while the respective one of the

detent arms

130 and 132 retains said members against movement toward the other end position, thus positively to retain the pull rod in each of its switch open and switch closed positions. In terms of tolerance, it is to be observed that the movable cone tact is somewhat elongated relative to the stationary contact 56 to accommodate a slight degree of pull rod play in the switch closed position, thereby to provide,

adequate clearance in the actuating mechanism for the purpose of latching the mechanism unfailingly in each of the end. positions of the bracket and the pull rod.

The operation of the actuating mechanism is as follows: With the pull rod and switch in closed position as shown in the. drawing, the crank arm 144 on the bracket 114 is in its lower end position, as indicated at A, and is positively retained therein by the roller 148', which engages the bottom of the slot 104 and prevents clockwise movement of the crank, and by the roller 136 on the, detent arm 132, which engages the step 128 on the bracket 114 and prevents counter-clockwise'movement thereof. Upon rotation of the actuator shaft 106 in a counter-clockwise direction (Fig. 3), by virtue of the movement imparted to the actuator arm 40 upon" opening movement of the blade 34 of the disconnect switch D, the bracket 110 and its tab 112 are rotated in-the same direction. The tab 112 engages the end 122'of the torsion spring and commences winding the spring more tightly about the shaft 106 due to the fact that the opposite end of the spring is retained against movement by the tab 116 of the bracket 114 which at this time is retained against movement. Tab 112 continues stressing the spring 118 until the tab 112 of the first bracket reaches substantially the position which is to be occupied by the tab 116 of the second bracket in the other end position of the second bracket. At approximately this position, the tab 112 adjacent its free end engages the cam surface 140 at the outer end of the detent arm which is then retaining the second bracket 114 against movement. Upon continued movement of the first bracket, the tab 112 cams the detent arm 132 outwardly until the roller 136 clears the step 128 on the cam surface 124. The total are of movement of the bracket 110 and shaft 106 in performing the described function is only about 75, as will be observed from Figure 3. Due to the rolling engagement provided between the detent arm and the bracket 114, frictional resistance to movement of the detent arm is practicallynil.

As the roller 136 clears the step 128, the bracket 114.

is released for movement in the counter-clockwise direc: tion, whereupon the highly stressed torsion spring 118,; by virtue of engagement of the end 120 thereof with the tab 116, rotates the bracket 114 rapidly in the counterclockwise direction to center the tab 116 relative to thetab 112. In this movement, the crank arm 144 is swung rapidly upward in an arc of about 75 from the position shown in Figure 3 to aposition indicated at B spaced substantially an equal distance to the opposite side of the horizontal center line of the slot 104, the crank arm being stopped in this position by virtue of engagement of the roller 148 in the bottom of the slot 104.

During the described movement, the

rollers

134 and 136 ride on the semi-circular portion of the cam surface 124. Slightly before attainment of the defined upper position of the crank arm 1 44, the step 126 of the cam surface clears the roller 134, whereupon the detent arm is snapped inwardly by the spring 142 to move the roller 134 intoblocking position behind the step 126 to'prevent-return movement of the bracket 11,4 and, crank arm 144: The bracket and crank arm are thereby positively latched in the upper position of the crank During the described movement of crank arm 144, the central part of the link 146, due to its pivotal connection to the free end of the crank, is rapidly swung in the same are as the free end of the crank. The end of the link 146 carrying the roller 148 is reciprocated in the slot 104 to accommodate the arcuate swing of the crank arm 144, the link itself pivoting about the floating pivot thus defined by the axis of the roller 148.

The end of the link 146 connected to the pull rod clevis is thereby moved substantially vertically upward from its lower position as indicated at X to an upper position indicated at Y, thereby to impart high speed movement to the pull rod.

In the preferred embodiment of the present invention, the axis of the guide slot 104 is disposed at right angles to the pull rod axis and the axis of the shaft 106 is disposed at right angles to and intersects the axes of both the slot and the pull rod. The crank arm 144 is pivotally connected to the center of the link 146, thereby to divide the link into two arms of equal length, namely 'a guide arm 146a and a link arm 146b. The crank arm 144 is of an efiective length (from the axis of the shaft 106 to its pivotal connection to the'link) equal to the length of each of the arms 146a and 14612. By virtue of this arrangement, the free end of the link arm 146b is moved in a straight line between the positions X and Y to impart purely linear movement to the pull rod whereby no lateral stress is imposed on the pull rod assembly. Variation from this preferred relationship may be adopted if desired, since the movement of the free end of the link arm 146b is quite close to a straight line movement for relatively short arcuate movements of the crank arm 144 when such arcuate movements have as their center the axis of the slot 104. However, the structural relationship shown in the drawing is preferred since it results in purely linear movement of the pull rod.

Moreover, by virtue of the above described arrangement, the pull rod is moved a distance equal substantially to twice the distance which the free end of the crank is moved (compare the distance A-B to the distance X'Y), thereby to afford wide linear separation of the swtich contacts as a consequence of a simple low speed arcuate input movement through about 75. In addition, this doubled movement results in a doubled speed of movement relative to the bracket 114 since the pull rod is moved twice as far as the crank arm in the same period of time. Accordingly, the wide linear separation of the contacts is accomplished at exceedingly high speed. Also, the rolling and pivotal connections established between the described components reduce requisite input energy to a minimum. To effect switch closing movement, the shaft 106 is rotated in the opposite direction, i.e., clockwise as viewed in Figure 3, due to engagement of the blade 34. of the disconnect switch D with the actuator arm 40 of the interrupter switch upon switch closing movement of the blade 34. Upon such movement, the tab 112 of the bracket 110 engages the end 120 of the spring 118 and stresses the same until the tab 112 engages and cams the detent arm 130 outwardly to clear the roller 134 from the step 126 of the bracket 114. The bracket 114 is then rapidly moved clockwise under the urge of the spring 118 to effect downward linear movement of the pull rod at high speed, thereby to close the interrupter switch with a minimum of arcing between the switch contacts.

In both directions of movement thereof, the bracket 110 and tab 112 are free to overtravel the respective end position of the second bracket to avoid undue dimensional limitations in the assembly of the interrupter on a disconnect switch or with other actuating means, and to insure proper operation of such means. Upon release of the actuator arm in a position of overtravel,

10 the torsion spring 118 will automatically center the tab 112 of the bracket 110 on the tab 116 of the bracket 114. In the use of the interrupter in combination with the disconnect switch, such accommodation for overtravel and automatic return of the actuator blade 40 is neocs-.

sary to permit the disconnect switch blade to clear the actuator blade and thereafter to return the actuator blade to a position in the path of the switch blade movement to be moved thereby upon reverse movement of the switch blade.

Substantially all of the components of the pull rod actuating means of the invention are formed of metallic electrically conductive material, thereby electrically to connect the actuator arm 40 and shaft 106 with the pull rod 76 of the contact 80 carried thereby. Specifically, the shaft 106, bracket 114, link 146, and clevis 78 are required to be formed of conductive materials to complete, in the closed energized condition of the interrupter, an electrical circuit from the stationary contact 22 to the blade 34 of the disconnect switch through the fitting 58, contacts 56 and 80, and actuator arm 40.

From the foregoing, it is apparent that the present invention provides a highly improved interrupter of simplified, economical construction facilitating combination of the same with a disconnect switch. The interrupter includes improved pull rod actuating means from moving the pull rod a substantial distance at exceedingly high speed in both the switch opening and switch closing directions, the means exerting a purely linear axial force on the pull rod. Accordingly, prompt interruption of current flow and mitigation of arcing upon switch opening and switch closing movements of the pull rod are assured, and no lateral thrust is applied to the pull rod thereby to prolong switch life. Also, the interrupter includes improved means for distributing erosion of the switch contacts and the gas evolving material over the full circumference thereof. further to increase the useful life of the switch components. Moreover, the interrupter includes improved arcing chamber means of a simplified and stable construction, insuring prompt extinction of electrical arcs occurring therein.

While we have shown and described what we regard to be a preferred embodiment of our invention, it is to be appreciated that various changes, rearrangements, and modifications may be made therein without departing from the scope of the invention, as defined by the appended claims.

We claim:

1. An interrupter switch comprising a tubular insulator defining an arcing chamber, a stationary contact in said chamber, a pull rod reciprocable in said chamber and carrying a contact movable into and out of engagement with said stationary contact, a conductive mounting element secured to one end of said insulator in conductive relation to said stationary contact, a casing secured to the opposite end of said insulator, pull rod actuating means in said casing comprising a base plate having a guide slot therein, a link slidably guided in said slot and pivotally connected to the pull rod, first and second brackets rotatable about a common axis and including tabs normally disposed closely adjacent and parallel to one another, a torsion spring having ends normally engaging the opposite sides of said tabs and normally centering said tabs on one another, said second bracket including a cam surface having a pair of spaced steps therein, and a pair of detent means alternately engaging: respectively in said steps to retain said second bracket alternately in a pair of angularly spaced end positions, said first bracket being rotatable from the end position in which said second bracket is retained toward the other at, high speed to said other end position, said second bracket including a crank arm pivotally connected to said link for imparting high speed movement. to said pull rod, an actuator arm to the exterior of said casing connected to said first bracket and electrically connected to said movable contact, a follower on said pull rod extending from said movable contactin the direction opposite said casing, a tubular liner in said insulator encircling said pull rod between said stationary contact and said casing, said liner and, said follower being formed .of a gas evolving material, a creeper spring rotatably mounted in said mounting element and including a portion intersect-' ing the, path of movement of said pull rod, and cam means. on said pull rod engageable with said portion of said creeper spring upon movement of said pull rod for alternately stressing and releasing said spring and causing the same to rotate angularly about said'pull rod, said cam means upon switch closing movement stressing the. spring whereby upon successive switch closing movements said spring exerts pressure on angularly spaced portions of said pull rod to induce initiation of the are occurring upon switch opening movement at angularly spaced points on the two contacts to equalize erosion of said contacts and said liner and said follower over the full circumference thereof.

2. An interrupter switch comprising a vertical tubular insulator defining an arcing chamber, a stationary contact in said chamber, a pull rodreciprocable in said chamber and carrying a contact, a mounting element at the lower end of said insulator connected electrically to said stationary contact, a casing at the upper end of said insulator, pull rod actuating means in said casing comprising a base plate having a guide slot therein, a link guided in said slot and pivotally connected to the pullrod, a pair of brackets journaled on said base plate, a torsionjspring normally centering said brackets relative to one another, one of said brackets, including a crank arm pivoted to said link and a cam surface having spaced steps therein, a pair of detent arms pivotally mounted on said base plate and alternately engaging against said steps to retain said one bracket alternately in a pair of angularly spaced end positions, the other bracket being rotatable toward the end position of said one bracket other than the one in which said one bracket is retained at the time to stress said torsion spring and to move the detent arm then retaining said onev bracket against movement out of engagement with the respective step, whereupon said torsion spring moves said one bracket at high speed to its other end position, said one bracket through said link imparting high speed linear movement to said pull rod. alternately to position said contacts in and out of engagement, an actuator arm to the exterior of said casing connected to said other bracket and electrically-connected to said movable contact, a follower on said-pull rod below said movable contact, a tubular liner in said insulator encircling said pull rod above, said stationary contact, said liner and said follower being formed of a gas evolving material, and a creeper spring rotatably mounted in said mounting element adjacent the lower end of said follower, said creeper spring including a portion intersecting the path ofmovement of the, lower end of the follower, said follower upon switch opening and closing movements alternately stressing and releasing said creeper spring and rotating the same angularly about said follower, said creeper spring in successive switch closed positions of said follower-bearing in sequence against angularly spaced portions of the follower to induce initiation of the. are occurring upon switch opening movement at angularly spaced points on the contacts to equalize erosion. of said contacts, said liner and said follower-over the full circumference thereof.

3. In an interrupter, switch having housing means and pull'rod means reciprocable in the housing means between switch open and switch closed positions, the improvement comprising a creeper spring mounted-in the housing means .for rotation about the axis of the pull rod means, said spring including a portion intersecting the pathof movement, of the pull rod means and cog operable therewith, the pull rod means including cam means engageable with said portion'of said spring, saidv said spring, said spring comprising a unitary leaf spring including a first portion forming a chord of said cylindrical bore and a second portion extending generally diametrically across said bore and having a free end engaging thewall of the bore, the centralpart of said second portion cooperating with said cam means.

5.. In an interrupter switch having a reciprocable contact carrying rod movable between a switch closed posi? tion and. a switch open position through a chamber formed of a. gas evolving material, the improvement comprising a creeper spring mounted for rotation about the axis of the rod and inculding a portion intersecting the path of movement of the free end of the rod at a point in said path intermediate the switch open and switch closed positions of the free end. of the rod, said spring upon successive switch opening and closing movements of the rod rotating a fraction of one revolution about the rod whereby said portion of said spring bears in sequence. against angularly spaced portions of the rod and biases the rod carried contact toward angularly spaced portions of the chamber to induce uniform erosion of the contact and the gas evolving material.

6; In an interrupter switch having a housing and a pull rod' reciprocable in the housing between switch open and switch closed positions, the pull rod including a contact and a gas evolving follower disposed to the side of the contact in the direction of switchclosing movement of the pull rod, the housing including a stationary contact encircling the pull rod and gas evolving liner means disposed to the side of the stationary contact in the direction of switch opening movement of the pull rod; the improvement comprising a creeper spring mounted inthe housing for rotation about the axis of the pull rod, said. spring including a portion intersecting the path, of movement of the pull rod and adapted to cooperate therewith, said spring in the switch open position being relae' tively relaxed, said pull rod including a cam surface engageable with said portion of said spring upon movement of the 'pull rod in switch closing direction, for stressing said spring, said cam surface upon successive switch opening and closing movements of the pull rodv alternately stressing and releasing said spring and causing said spring to index angularly about the axis of the pull rod, said portion of said spring on successive switch closing movements of the pull rod exerting pressure on angu -v larly spaced portions of the pull rod to induce initiation of the are occurring upon switch opening movement at angularly spaced points on the two contacts to equalize erosion of the contacts and the gas evolving liner and follower over the full circumference thereof.

7. In a load break switch assembly including a disconnect switch having a blade movable into and out of a stationary contact, and an interrupter switch including a terminal connected to said contact, a reciprocable contact rod for opening and closing a circuit at said terminal, an actuating arm electrically connected to said contact rod and disposed to be moved by the disconnect switch blade, and actuating mechanism associated with said arm and saidrod for efiecting high speed actua-- tion of said rod upon occurrence of predetermined movement of said arm by said blade; the improvement comprising that said actuating mechanism comprises a base plate having a guide slot, a link slidably guided in said slot and pivotally connected to said rod, a crank arm oscillatable between two end' positions and pivotally connected to said link, detent means retaining said crank arm in the end position to which last moved, torsion spring means acting on said crank arm for moving the crank arm between the two end positions, and an actua tor connected to said actuating arm and disposed concentric with the axis of oscillation of said crank arm, said actuator engaging said torsion spring means and being engageable with said detent means upon movement toward the same for progressively stressing said-spring means and for releasing said detent means at a point of maximum spring stress for effecting high speed actuation of said crank arm and thus of said contact rod, said spring and detent means causing said actuator, said actuating arm and said contact rod to assume two respective end positions in one of which said contact rod closes a circuit with said terminal and said actuating arm extends into relative proximity to said stationary contact for engagement by said disconnect switch blade before the blade clears said contact and during subsequent movement of said blade away from said contact, and in the other of which said contact rod is separated from said terminal to open the circuit andsaid actuating arm extends into a relatively widely separated position with respect to said stationary contact for engagement by said blade at a point in its path of movement toward said stationary contact well in advance of the contact and during its movement into engagement with said contact, said actuator releasing said detent means during movement of said actuating arm by said blade, said torsion spring means causing said actuating arm to be retained in engagement with saidblade during spring actuated movement of said crank arm and said blade constituting the reaction point for said torsion spring means during such movement, said torsion spring means accommodating over travel of said actuator and said actuating arm subsequent to actuation of said contact rod in both directions for permitting said disconnect switch blade to be moved clear of said actuating arm, whereby the electrical circuit consists solely of said disconnect switch blade, said stationary contact, said contact rod, said terminal and said actuating arm'and mechanism, the circuit is opened and closed by said interrupter switch, and there is no arcing externally of the interrupter switch since the circuit through the assembly is never opened externally thereof.

8. In a load break switch assembly having the improvements set forth in claim 7, said guide slot being located to one side of the pivotal connection of said crank arm and said link, the end of said slot adjacent said pivotal connection defining an abutment limiting movement of said crank arm, said link and said contact rod at both ends of the respective paths of movement.

9. In a load break switch assembly including a disconnect switch having a blade movable into and out of a stationary contact, and an interrupter switch including a terminal electrically connected to said contact, a reciprocable contact rod for opening and closing a circuit at said terminal, an oscillatable actuating arm electrically connected to said contact rod and disposed to be moved by the disconnect switch blade, and actuating mechanism associated with said arm and said rod for effecting high speed actuation of said rod upon occurrence of predetermined movement of said arm by said blade; the improvement comprising that said actuating mechanism comprises a shaft secured to said actuating arm, a first bracket secured to said shaft, a second bracket rotatable on said shaft, said first and second brackets including spaced parallel base portions, said base portions each including a tab extending toward the other base portion parallel to and spaced from said shaft, said tabs normally being dis posed closely adjacent and parallel to one another in radially spaced relation, a torsion spring disposed between said base portions about said shaft and having ends normally engaging theopposite sides of said tabs and normally centering said tabs on one another, the base portion of said second bracket including an arcuate cam surface concentric with said shaft and having a pair of circumferentially spaced steps therein, and a pair of detent means alternately engaging respectively in said steps to retain said second bracket in a pair of angularly spaced end positions, said shaft being rotatable to move the tab of said first bracket in the direction toward the position occupied by the tab of said second bracket in the end position of said second bracket other than the one in which said second bracket is retained at the time progressively to stress said spring, said first bracket, when the tab thereof is in a position corresponding substantially to the other end position of the tab on said second bracket and at a point of maximum spring stress, engaging the detent means then holding the bracket against movement and releasing said detent means whereupon said spring moves said second bracket at high speed to its other end position, said second bracket being operatively connected to said contact rod, said spring and said detent means causing said actuating arm and said contact rod to assume two respective end positions in one of which said contact rod closes the circuit with said terminal and said actuating arm extends into relative proximity to said stationary contact for engagement by said disconnect switch blade before the blade clears said contact and during subsequent movement away from said contact, and in the other of which said contact rod is separated from said terminal to open the circuit and said actuating arm extends into a relatively widely separated position with respect to said stationary contact for engagement by said blade at a point in its path of movement toward said stationary contact well in advance of the contact and during its movement into engagement with said contact, said first bracket releasing the respective detent means during movement of said actuating arm by said blade, said torsion spring causing said actuating arm to be retained in engagement with said blade during spring actuated movement of said second bracket and said contact rod and said blade constituting the reaction point for said torsion spring during such movement, said torsion spring accommodating overtravel of said first bracket and said actuating arm subsequent to actuation of said contact rod in both directions for permitting said disconnect switch blade to be moved clear of said actuating arm, whereby the electrical circuit consists solely of said disconnect switch blade, said stationary contact, said terminal, said contact rod and said actuating arm and mechanism, the circuit is opened and closed by said interrupter switch and there is no arcing externally of the interrupter switch since the circuit through the assembly is never opened externally thereof.

10. In a load break switch assembly including a disconnect switch having a blade movable into and out of a stationary contact, and an interrupter switch including a terminal electrically connected to said contact, a reciprocable contact rod for opening and closing a circuit at said terminal, an oscillatable actuating arm electrically connected to said contact rod and disposed to be moved by the disconnect switch blade, and actuating mechanism associated with said arm and said rod for effecting high speed actuation of said rod upon occurrence of predetermined movement of said arm by said blade; the improvement comprising that said actuating mechanism comprises a base plate having a guide slot, a link slidably guided in said slot and pivotally connected to said rod, a shaft journalled on said base plate and secured to said actuating arm, first and second brackets rotatable about the axis of said shaft, the axes of said shaft, slot and rod each being perpendicular to the other two, said brackets il- 15 eluding spaced parallel base portions and oppositely extending tabs normally'disposed closely adjacent and parallel to one another, a torsion spring encircling said shaft between the base portions of said brackets and having transversely extending end portions normally engaging the opposite sides of said tabs and normally centering said points the distance between which is less than the distance between said steps, said arms alternately engaging respectively against said steps to retain said second bracket alternately in a pair of angularly spaced end positions, said first bracket being secured to said shaft and rotatable by said actuating arm to move the tab thereof toward the position occupied by the tab of said second bracket in the end position of said second bracket other than the one in which said second bracket is retained at the time progressively to stress said spring, the tab of said first bracket upon movement to the position corresponding substantially to the other end position of the tab on said second bracket and at a point of maximum spring stressmoving the detent arm then holding the second-bracket out of engagement with the respective step whereupon said spring moves said second bracket at high speed to its other end position, said second bracket includinga crank arm pivotally connected to said link for impartinghigh speed linear movement to the contact rod, said spring and det'ent arms causing said actuating arm and said contact rod to assume two respective end positions in one of which said contact rod closes the circuit with said terminal andsaid actuating arm extends into relative proximity to said stationary contact for. engagement by said disconnect switch bladebefore the blade clears said contact andduring subsequent movement away from said contact, and in theoth'erof whichsaid contact rod is separated from said terminal at a point in its path of movement toward said stationary contact Well in advance of the contact and during its movement into engagement with said contact, said first to-openthe'circuit'and said actuating arm extends into a relatively widely separated position with respect to said stationary contact structure for engagement by said blade bracket releasing the respective detent arm during movement of said actuating arm by said blade, said spring caus- 7 ing said actuating arm to be retained in engagement with said blade during spring actuated movement of said second bracket and said contact rod and said blade constitut ing the reaction point for said spring during such movement, said spring accommodating overtravel of said first bracket and said actuating arm subsequent to actuation of said contact rod in both directions for permitting said disconnect switch blade to be moved clear of said actuating arm, whereby the electrical circuit through said assembly consists solely of said disconnect switch blade, said sta-: tionary contact, said contact rod, said terminal and said actuating arm and mechanism, the circuit is opened and closed by said interrupter switch and there is no arcing externally' of the interrupter switch since the circuit through the assembly is never opened'externally thereof.

References Cited in the file of thispatent UNITED STATES PATENTS