US2548079A - Circuit isolating air break switch - Google Patents

Description

A ril 10, 1951 J. 5. THOMPSON EI'AL ,0

CIRCUIT ISOLATING AIR BREAK SWITCH .5 Sheets-Sheet 1 Filed Sept. 24, 1948 it I wW y INVENTOR. ZhJEPHJ 77/07/ 50 y mm (WA/P055 R 760 A from/5 April 10, 1951 J. S. THOMPSON ET AL CIRCUIT ISOLATING AIR BREAK SWITCH Filed'SeiJt. 24, 1948 3 Sheets-Sheet 2 Ap 1951 J. s. THOMPSON arm. 2,548,079

CIRCUIT ISOLATING AIR BREAK SWITCH 3 Sheets-Sheet 5 Filed Sept. 24, 1948 I l I INVENTOR. z/oszzw 61 7210x1 50 A/YD MLESRRQY ATTORNEY Patented Apr. 10, 1951 CIRCUIT ISOLATING AIR BREAK swrrcn Joseph S. Thompson, San Francisco, and Charles R. Ray, Sausalito, Calif., assignors to Pacific Electric M nu t rin Corporation,

San

Francisco, Calif., a corporation of California Application September 24, 1948, Serial No. 50,968

1 5 Claims.

Our present invention relates to a new and improved branch line circuit isolating switch and more particularly to an automatically operating switch which may be employed in conjunction with a main line circuit opening and reclosing circuit breaker to isolate a consumer line circuit in the event of a permanent fault or overload therein.

An object of our invention is to provide a circuit isolating switch of novel construction in which the circuit opening operation of the switch is timed. to occur after a predetermined number of circuit opening and restoring operations have occurred in the circuit.

A further object cf the invention is to provide a circuit disconnecting switch for use With an automatically operating main line reclosing circuit breaker in which the opening operation of the switch is delayed in a novel manner until a time when no current is flowing therethrough.

Another object of the invention is to provide an automatic tripping means for a circuit isolating switch in which the tripping is controlled and timed in a novel manner by a novel latching means and in which an opening of th circuit through the switch will be prevented when current is flowing therethrough.

While the prior art provides many circuit interrupting devices suitable to the purposes for which our invention is intended these circuit interrupters have, in the main, required complicated parts and mechanisms to effect their successful operation and it is therefore a further object of our invention to provide a circuit inter.- rupting switch of simple and of inexpensive construction that may be relied upon to perform its normal function without resort to a complicated operating mechanism and/or the use of arc quenching means such as oil emersed contacts.

Other objects and advantages of our invention will be in part evident to those skilled in the art and in part pointed out in connection with the accompanying drawing, wherein there is shown by way of illustration and not of limitation a preferred embodiment of the invention.

In the drawings:

Figure l is a perspective view showing a switch constructed in accordance with the preferred embodiment of our invention,

Figure 2 is a sectional view taken along line IIII of Figure 1, looking in direction of arrows, Figure 3 is a sect onal view taken along line III-III of Figure 2, looking in direction of arrows, Figure 4 is a fragmentary perspective view showing a detail of our switch blad is flowing therethrpllghshown in Figure 5 with a portion of the casing cut away t r eal nn r d tails.

Figure 9 is a horizontal sectional view taken along li e IX-l of Fig e Fi ure it is a fr men ar si ew partia y n ec on howin a ortion o t mechanism llu trated n Fi ure 5,

Figure 11 is a fragmentary perspective view h in the ratche m chanism of h timing device employed. y our in en n, and

ures 12 and 13 are fra men a si e ws showing the operating mechanism in different positions of operations,

As distinguished from other automatically opera-ting circuit isolating switches provided for use under conditions contemplated by our invention, our circuit isolating switch is so arranged that it will not operate to isolate a faulted circuit protected thereby until after the main line circuit breaker has opened and reclosed a predetermined number of times. Then as an additional advantage our circuit isolating switch is so designed that it cannot operate under conditions which would cause a destructive arcing to occur therein. By our invention we have dispensed with the means usually employed to bias the moving cone tact or blade into a circuit open position and rely upon the inherent resilience of a circuit completipg member in the form of a switch blade that operates in a novel manner. In accordance with this disclosure the switch blade is of flexible con.- struction and is adapted to be flexed fiatwise into a circuit closed position where it is held in a stressed condition by a cooperating contact that is arranged to act as a latchin means. In this way the blade performs the dual function of com.- pleting the circuit and also opening the circuit without reliance upon gravity or a spring operated means for accomplishing a circuit opening movement of the switch blade. In conjunction with the latc in ype of contac d fin above, we a s m loy a o el control fo t s a hin contact which will permit a release of the switch bl on under ain p edetermi ed conditions of operation and at a time when no current In t is way we ha e provided an air-break circuit interrupter in which no arcing can occur between the cooperating circuit completing contacts when current is flowing therethrough and as a consequence no special precautions, such as the use of oil emersed contacts, need to be taken to avoid the arcing hazard which generally prevails in other circuit isolating devices of a comparable character.

For a general description of the invention, reference is now made to sheet of the drawings where in Figure l the numeral ll] designates an elongated insulator which serves as an insulating support for terminal mountings II and I2 that are secured at the opposite ends thereof by encircling bands l3 and M. Intermediate its ends the insulator I is also engaged by an encircling band I5 which incooperation with a bracket it serves as a means for mounting the switch as a whole upon a cross-arm ll of a pole or like structure. In this instance the bracket I6 is shown as secured to the cross-arm IT by a conventional mounting I8. Mounted upon the terminal support l2 at the upper end of the insulator i0 there is an automatic tripping mechanism, to be hereinafter described, and which is completely enclosed within a housing I9. At the lower end of the insulator ill the terminal mounting carries a pivotal support 20 upon which a switch blade 2| is pivotally mounted to move flatwise into and out of cooperating relation with a latching contact 22 which, as will hereinafter appear, is also mounted within the housing l9. In this showing and as is more clearly shown in Figure 4 the switch blade 2| has an integrally formed tongue or projection 23 that is adapted to be engaged by an operating pole 24, here shown by dot and dashlines. By referrin to Figures 2 and 3 of the drawings it will also be noted that the pivotal support 20 upon which the lower end of the switch blade 2| is mounted has an overhanging skirt-like portion 25 that extends downwardly over a hinge forming pin 26. This overhanging portion 25 will interfere with a free circuit closing movement of the switch blade 2| as it approaches its final circuit closed position and as a consequence the switch blade 2|, in being moved further into its full circuit closed position and in latched relation with the contact 22, will be flexed and stressed in such a manner that when released by the latching contact 22 it will inherently snap open and interrupt the circuit without reliance upon any other operating means. In these figures of the drawings it will also be noted that the pivotal support 20 also carries a laterally extendin lug 21 which forms a terminal for a power line conductor 28.

Upon now referring to Figure 5 of the drawings it will be seen that the housing I!) has an opening inits lower wall through which the switch blade engaging contact 22 is projected when in its normal operating position. As here shown, the contact 22 is mounted upon a pivotal supporting member 29 that is biased upwardly by means of a tension spring 30. Operating in opposition to the tension spring 30 there is a pair of links 3i and 32 that are connected together in coextending relation by a pin 33 so as to form a toggle which when extended will retain the -contact 22 in its normal operating position. The link 32 in this particular instance has an overhanging lip 34 that is arranged to hold the links 3| and 32 in a slightly over-center position when jextended as here shown. Arranged in cooperating relation with the toggle formed by these links 3| and 32 there is also a manually operable toggle collapsing member 35 that has a depending stick engageable hook 36 by which it may be operated to collapse the toggle and thus cause a circuit opening operation of the switch blade 2| under certain conditions. This toggle collapsing member 35 is biased into its normal inoperative position by means of a compression spring 3? carried by a boss 38 extending from the back wall of the housing l9. In order to effect an extension of the toggle formed by the links 3| and 32, when the switch blade 2| is moved into its circuit closed position, the member 29 which carries the contact 22 also carries a blade engaging leaf spring 39 which when engaged by the switch blade 2| in its final circuit closing movement will cause the contact supporting member 29 to rotate clockwise about its pivotal mounting, here designated by the numeral it, and thus bring the depending contact 22 into latching relation with the end of the switch blade 2|. In addition to performing the above function this leaf spring 39 also serves to maintain a good pressure engagement between the contacting surfaces of the switch blade 2| and its cooperating contact 22. The pivotal contact supporting member 29 is also shown grounded upon the housing l9 through a flexible jumper 4|.

With the above described arrangement and a line terminal connection directly to the housing H] by a conductor 4| it will be seen that we have provided a circuit interrupting or disconnecting switch which may be operated entirely in a manual manner assuming, of course, that the other line terminal lug 21 is connected to the other side of the circuit through the conductor 28. In other words, with this arrangement the switch blade 2| may be moved into its circuit closed position by the application of force thereto through the operating stick 24 when placed in engagement with the tongue 23 upon the switch blade. At this time the cooperating contact 22 carried by the pivotal supporting member 29 will be in its raised or counter-clockwise position. consequently as the outer end of the switch blade 2| is brought into engagement with the leaf spring 39 the pivotal supporting member 29 will be caused to rotate clockwise and thus carry the cooperating contact 22 into latching relation with the end of the switch blade 2 During this final movement of the switch blade 2| the contact supporting member 29 will also move downwardly and the toggle formed by the links 3| and 32 will become extended and assume the over-center position and thus latch the switch blade 2| in its circuit closed position. Now to open the circuit the operating stick 24 will be brought into engagement with the depending hook 36 and by a pull thereupon the toggle collapsing member 35 will be turned counter-clockwise so that its toggle engaging end will contact with the toggle link connecting pin 33 and move the toggle over center where it can collapse under the action of the tension spring 39. In this connection reference is made to Figure 6 of the drawings wherein the operating hook 36 is shown as having an arcuate portion 42 that has a cam surface 43 arranged to contact with the link connecting pin 33 as it moves counter-clockwise about its pivotal mounting 48. As here shown the hook member 36 also has a small spring centering lug 44 which serves to hold its biasing spring 31 in cooperating relation' therewith.

. operable aspect of our invention to a form of operation by which it may be associated with an automatically operating reclosing circuit breaker to control a branch line circuit as is contemplated by our invention, we have shown the housing [9 as extending upwardly by a cover-like portion 45 in which there is positioned an electromagnetic operating coil 45. This operating coil 45 is con nected in series circuit with the switch blade 21. Under these conditions the line conductor 4! will be insulated from the housing l9 and is connected to one side of the coil 45 through a terminal 41. The other side of the electromagnetic operating coil 46 is then connected to the housing l9 through a terminal 48. With this circuit arrangement the current flowing through the switch blade 2| will also flow through the electromagnetic coil 45. When an overload occurs in this circuit the electromagnetic coil 45 will attract a cylindrical armature 49 which carries a link 50 that is connected at its lower end to a step by step ratchet mechanism which, as will presently appear, is adapted to trip the toggle formed by the co-extending links 31 and 32 after a predetermined number of operations thereof. These said step by step operations of the ratchet must also occur within a predetermined period of lapsed time. Before proceeding with the description of this ratchet mechanism attention is called to the fact that the link 50 has a transverse pin 5| which is engaged by a compression spring 52 carried by the cylindrical armature 49 and intermediate its ends the link 56 also has a second pin 53 that is engaged by the lower end of the armature 49. These pins 5| and 53 thus retain these parts in connected relation and in this way there is established a cushioned connection between the armature 49 and the link 56 which will absorb any sudden shock that might be injurious to the ratchet mechanism. In the upper end of the cover portion 45 of the housing l9 there is also a cushion stop 54 which slides upon a central support 55 around which a cushioning spring 55 is disposed.

In addition to the electromagnetic operating means described above, our invention also contemplates the employment of a timing device which is enclosed within a separate housing 57 that is mounted upon the back wall of the housing 19 and from which there extends an operating pinion 58. This timing device is of conventional design and consists of an anchor type escapement which will retard rotation of the pinion 58 in a counter-clockwise direction. Meshing with the timing pinion 58 there is a freely rotatable timing gear 59. This gear 59, as is more clearly shown in Figures 5, 7 and 11, is journaled to rotate freely about a stub shaft 66 that extends from the back wall of the housing 19 and engaging the teeth at its periphery there is a tooth engaging dog ii that is carried by an arm 52 extending from a ratchet disc This ratchet disc 63 is keyed upon a sleeve 4 that is also journaled for free rotation upon the stub shaft 55 and it is biased to rotate in a clockwise direction as viewed in Figure 5, by means of a spring 55 which terminates at its outer end in a tension setting means 65 that extends through the front wall of the housing is, as shown in Figure l of the drawings. Associated with the ratchet disc 53 and engageable with notches formed thereupon there is a second dog 5! that is pivotally mounted together with an arcuate link 68 upon a dog carrying member 69 which is rotatably mounted upon the sleeve 64. The arcuate link 98 is connected at til mean" its other end to the link 50 which is controlled by the armature 49 and it is so disposed that when an upward movement is imparted thereto by an attraction of the armature 49 it will operate to throw the ratchet engaging dog 61 into contact with the notches in the ratchet disc 63. Extending sidewise from the dog carrying member 69 there is an arm 10 which is adapted to cooperate with a latching member it that operates, as will hereinafter appear, to prevent a complete collapse of the toggle formed by the links 3| and 32 while current is flowing through the switch blade 2!. The ratchet disc 63 has three notches, designated by the numerals I2, 13 and 14, and it therefore provides for a complete operation which entails at least three reclosings of a main line circuit breaker associated therewith or, in other words, three complete actuations of the armature 49 before the toggle mechanism formed by the links 3| and 32 can be collapsed to permit an opening of the circuit by a release of the switch blade 2|. At the same time due to the timing mechanism contained in the housing 51 these three actuations of the armature 49 will have to occur within a predetermined period of lapsed time otherwise the reverse movements of the timing gear 59 under the influence of its biasing spring 65 will prevent the ratchet operating dog (3'! from successively engaging the notches I2, 13 and 74 upon the ratchet disc 63 and thus advancing the arm 52 ca ried thereby into a position where the end of this arm 52 will engage with the toggle forming link 32, as shown in Figure 13, and cause the toggle to partially collapse and thus later permit a, complete collapse that will cause the contact carrying member 29 to move upwardly and carry the cooperating contact 22 out of latching relation with the end of the switch blade 2 I. When this occurs and the toggle is thus par tially collapsed'by the extending end of the arm 62 of the ratchet disc 63 the projecting arm 10 extending from the dog carrying member 69 will be in a vertical position and out of engagement with the latching member TI and as a result this latching member '7! will assume a raised position, as shown in the Figures 12 and 13 of the drawings, where it will be engaged. by a pin 15 carried by the link 3! of the toggle. As a result the toggle mechanism formed by the links 3i and 32 will be held against a total collapse and thus prevent an opening of the circuit through the switch blade 2|. In these latter figures of the drawings the parts of the mechanism are respectively shown in the positions which they will assume on the two successive final actuations of the armature 49 and with the electromagnetic coil as fully energized. As soon as the electromagnetic coil 46 is deenergized by an opening of the main line reclosing circuit breaker and with the parts in the positions shown in Figure 13, the armature 49 will drop and permit the arm 19 carried by the dog carrying member 59 to turn clockwise and move the latching member H downwardly against the action of its upward biasing spring 16 and thus permit a full collapse of the contact holding toggle formed by the links 3! and 32.

It is believed with the above description taken in connection with the remainingfigures of the drawings that the operation of our improved circuit isolating switch when installed with an automatically operated reclosing circuit breaker will be clearly understood. Therefore, it should remain necessary to only state that should an overload occur upon the branch line in which our switch is connected, this overload will also be simultaneously impressed upon the main line circuit breaker. This will cause the main line circuit breaker to immediately open and reclose and upon each reclosing of the main line circuit breaker following the initial overload actuation of the armature t!) the ratchet disc 63 will be advanced in a step by step manner until its dog carrying arm 62 has been brought around counter-clockwise and into collapsing relation with the toggle formed by the links 3i and 32 after which a subsequent opening of the main line circuit breaker will permit the arm ill to drop and trip the latching means 1i and permit the toggle formed by the links M and 32 to completely collapse under the influence of its biasing spring 30 and thus cause a release of the switch blade 2! and a consequent opening of the circuit therethrough.

, While we have, for the sake of clearness and in order to disclose the invention so that the same can be readily understood, described and illustrated specific devices and arrangements, we desire to have it understood that this invention is not limited to the specific means disclosed, but may be embodied in other ways that will suggest themselves to persons skilled in the art. It is believed that this invention is new and all such changes as come within the scope of the appended claims are to be considered as part of this invention,

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. In a branch line circuit interrupting switch for use with an automatically operated main line reclosing circuit breaker, the combination of a pair of spaced insulating supports, a circuit controlling switch blade pivotally mounted upon one of said supports for movement into and out of a circuit closed position, a terminal contact hingedly mounted upon the other of said supports adapted to move into latching relation with the end of said switch blade, a toggle for retaining said hingedly mounted terminal contact in latching relation with said switch blade, electromagnetic means operative through a member for initiating a collapse of said toggle to permit said pivotally mounted terminal contact to swing out of latching relation with said switch blade following a predetermined operation thereof, and a blocking means for preventing a full collapse of said toggle when said electromagnetic means is energized and current is flowing through said switch blade.

2. In a circuit interrupting switch of the character described, the combination of a pair of spaced insulating supports, a switch blade pivotally mounted upon one of said supports and moveable into and out of a circuit closed position, a terminal contact hingedly mounted upon the other of said supports adapted to move into latching relation with said switch blade and hold it in a circuit closed position, a toggle means adapted and arranged to be extended by said hingedly mounted terminal contact as it moves into latching relation with said switch blade and retain said pivotally mounted terminal contact in its switch blade latching position, electromagnetic means responsive to line current conditions connected in series circuit with said switch blade, a toggle tripping lever controlled by said electromagnetic means for eiiecting a partial collapse of said toggle means after a predetermined number of operations of said electromagnetic means, a mechanical blocking means operating independently of said toggle tripping lever for preventing a complete collapse of said toggle means when said electromagnetic means is energized, and means set in motion upon a predetermined deenergization of said electromagnetic means for rendering said blocking means ineffective to prevent a. complete collapse of said toggle means after said electromagnetic means has completed said predetermined number of operations.

3. In a circuit interrupting switch of the character described, the combination of a pair of spaced insulating supports, a switch blade pivotally mounted upon one of said supports and moveable into and out of a circuit closed position, a terminal contact hingedly mounted upon the other of said supports adapted to move into latching relation with said switch blade and hold it in a circuit closed position, a toggle means adapted and arranged to be extended by said hingedly mounted terminal contact as it moves into latching relation with said switch blade and retain said pivotally mounted terminal contact in its switch blade latching position, electromagnetic means responsive to line current conditions connected in series circuit with said switch blade, a ratchet mechanism operated in a step by step manner by a series of successive operations of said electromagnetic means, a toggle tripping lever adapted and arranged to be advanced into an operative position by said ratchet mechanism to cause a partial collapse of said toggle means, a timing device set in operation by an initial energizing of said electromagnetic means for rendering said ratchet mechanism inoperative to advance said toggle tripping lever into its operative position when the successive operations of said electromagnetic means do not occur within a predetermined period of lapsed time, a mechanical blocking means operating independently of said toggle tripping lever for preventing a complete collapse of said toggle means when said electromagnetic means is energized, and means operable after said electromagnetic means has completed said predetermined number of successive operations for rendering said blocking means ineliective to prevent a complete collapse of said toggle means.

4. In a circuit interrupting switch of the character described, the combination of a pair of spaced insulating supports, a switch blade pivotally mounted upon one of said supports and moveable into and out of a circuit closed position, a terminal contact hingedly, mounted upon the other of said supports adapted to move into latching relation with said switch blade and hold it in a circuit closed position, atoggle means adapted and arranged to be extended by said hingedly mounted terminal contact as it moves into latching relation with said switch blade and operating to retain said pivotally mounted terminal contact in its switch blade latching position, electromagnetic means connected in series circuit with said switch blade for tripping said toggle means under predetermined line current conditions, a manually operated means for tripping said toggle means independently of said electromagnetic means,-a mechanical blocking means for preventing a tripping of said toggle by said manual means when said electromagnetic means is energized, and means controlled by said electromagnetic means for rendering said mechanical blocking means inoperative only when no current is flowing through said switch blade.

5. A quick acting air break circuit interrupting switch, comprising a current conducting blade of flexible construction pivotally mounted to swing flatwise into and out of circuit establishing engagement with a cooperating contact, means at the pivotally mounted end of said switch blade adapted to prevent a free pivotal movement thereof at a point short of its full circuit closed position, whereby said blade will be placed under a stress tending to impart a circuit opening movement thereof when in its circuit closed position, a contact adapted to be brought into latching and circuit completing engagement with the end of said blade, a toggle mechanism for retaining said circuit completing contact in latching relation with the end of said switch blade when under said stress, an electromagnetic toggle tripping mechanism adapted to partially collapse said toggle upon a predetermined operation thereof, operating means for moving said toggle tripping mechanism, a blocking means for preventing a full collapse of said toggle mechanism until and after said electromagnetic tripping mechanism has completed said predetermined operation, and means actuated by said operating means for said toggle tripping mechanism for rendering said blocking means inoperative immediately following the said partial toggle tripping operation thereof, whereby a separation of said switch blade and said cooperating contact will be prevented when current is flowing therethrough.

JOSEPH S. THOMPSON. CHARLES R. RAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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