US2106114A - Circuit breaker - Google Patents

Description

Jan. 18, 1938.

, H. J. CRABBS CIRCUIT BREAKER Filed Nov. 5, 1934 5 Sheets-Sheet l vi i WTNESSES: 5 5

ATTOR Y Jan. 18; 1938. CRABBS 2,106,1 14

CIRCUIT BREAKER Filed Nov. 3, 1934 3 Sheets-Sheet 2 I WITNESSESI INVENTOR ATTORN Jan. 18, 1938. J CRABBS 2,106,114

CIRCUIT BREAKER Filed Nov. 5, 1934 3 Sheets-Sheet 3 III/I/Il/Il/IIIIII II/IIIIIIIIIII "1111.

2 75 7/ 27 u fi WITNESSES: INVENTOR ATTORN Y Patented Jan. 18, 1938 UNITED STATES PATENT OFFICE cmcorr BREAKER Pennsylvania Application November 3, 1934, Serial No. 751,290

13 Claims.

My invention relates to circuit interrupters and particularly to electrical switches of the type which are used for isolating or sectionalizing portions of a transmission line or a power distribution system.

Switches of this type are generally known as disconnecting switches and their primary function is to provide a means whereby particular apparatus or sections of transmission line may be positively disconnected from all sources of power in order that maintenance work may be done thereon with absolute safety to the workmen. For several reasons, the design of these switches has always presented a rather complex problem to the electrical art, and with the advent of the long distance transmission line, the problem has become considerably more complicated.

Usually the switches are mounted out of doors and in the ordinary course of their operation, 7

they are actuated but infrequently, both of which conditions combine to provide an almost ideal condition for oxide corrosion formation. Despite this infrequency of operation of the switches, it is imperative they shall be absolutely reliable when an operation is necessary. In the Northern States, this means that they must include some arrangement for taking care of ice and sleet formations.

In the older systems, the disconnecting switches were practically never called upon to open any appreciable load currents. Under present day conditions on long distance transmission lines, however, the line charging current is often sufiiciently high to make the opening of the circuit impractical with a simple air break switch, andsome means must be provided for increasing the arc interrupting capacity of the devices. One method of accomplishing this has been pointed out in my copending application Serial No. 739,- 891; and the principal object of the present invention is the improving of devices of that type.

The problem of providing a commercially satisfactory disconnecting switch which is capable of interrupting arcs of considerable magnitude is further complicated because of the fact that the cost of the switches must be kept comparatively low, due to the large numbers of these devices which are used on even a small system. Another important object of my invention, therefore, is to provide a high capacity disconnecting switch which shall be capable of interrupting considerable amounts of power and which, at the same time, shall be comparatively low in cost.

These objects are accomplished in the preferred embodiment of my invention through the provision of a switch which includes a blade and contact structure and an auxiliary expulsion type circuit interrupter, which is normally connected in parallel with the blade structure, but which is operable during the switch opening operation to control and to extinguish the are formed incident to the opening of the electrical circuit through the switch. To reduce the cost of the device to a minimum and to simplify its structure as much as possible, I prefer to utilize a gravity operated actuating mechanism for the expulsion interrupter. Through this arrangement it becomes possible to completely enclose all of the moving parts of the expulsion type interrupter, thus assuring its satisfactory operation under all possible conditions.

As a further means for reducing the cost and for assuring more reliable operation of my improved switch, I prefer to utilize a blade structure for the main current carrying portion of the device which shall be provided with means for producing a high pressure wiping engagement between the cooperative contact surfaces during the circuit closing operation. By doing this, a very considerable reduction in the physical dimensions of the arc extinguishing portion of the switch is made possible with obvious resultant economies, at the same time, the low resistance of the blade structure which results from the high pressure wiping engagement of the contacts, assures that the amount of current which flows through the arc extinguishing device shall not reach an excessively large value during the normal operation of the switch.

A further object of my invention is to provide an improved means for effecting the successive operation of two cooperating circuit interrupting devices which may be, but are not necessarily electrically connected in parallel.

An ancillary object of my invention is to provide an improved gravity operated, expulsion, circuit interrupting device which shall be suitable for use with electrical apparatus generally.

These and other objects of my invention will be made more apparent in the following drawings and description of an electrical switch wherein are embodied the principal features of my invention. Referring to the drawings,

Figure 1 is an elevational view of a vertical break disconnecting switch which has been provided with an auxiliary expulsion circuit interrupting device according to my invention,

Fig. 2 is a plan view of the switch illustrated in Fig. 1.

Fig. 3 is a fragmentary elevational view show ing one of the moving parts of the switch illustrated in Figs. 1 and 2 at one of the intermediate positions in the circuit opening operation.

Fig. 4 is a view similar to Fig. 3, showing the moving portions of the switch in the open circuit position.

Fig. 5 is a sectional view through the expulsion circuit interrupting device which is embodied in the switch shown in Figs. 1 through 4.

Fig. 6 is an enlarged sectional view taken on the line VIV'I of Fig. 5.

Fig. 7 is an enlarged sectional view taken on the line VII-VII of Fig. 5, and

Fig. 8 is an enlarged fragmentary view, partially in section, of the contact structure disposed at the outer end of the arc extinguishing device shown in the other figures of the drawings.

.As shown particularly in Figs. 1 through 4, the preferred embodiment of my switch includes a base I, which may be formed of channel iron, two stationary insulators 3 and 5 afllxed thereto by suitable bolts 1, and a rotatable insulator 9 which is rotatably supported on the base through a bearing means I. Each of the insulators is of the conventional high voltage type and, in addition to a base II and a ceramic central portion l3, includes a metallic cap l5. A blade assemblage I1 is supported upon the cap portion of the central insulator 5 for swingable motion from one position to the other through the agency of a U-shaped support 19 and a pin 2| and is adapted to engage a suitable contact jaw 23 supported on the cap portion of the outer stationary insulator 3.

An expulsion circuit interrupting device 25 of considerably greater arc extinguishing capacity than the movable blade assemblage I1 is pivotally supported upon a suitable bracket member 21 which projects upwardly from the U-shaped blade support means l9 afllxed to the central insulator. This device is normally electrically in parallel with the blade assemblage I! when the interrupter is in the closed circuit position, and is adapted to be moved to the open circuit position during each circuit interrupting operation only after the blade assemblage I! has been swung out of engagement with the cooperating contact means 29 supported on the outer insulator 5. By this arrangement, the electrical circuit through the switch is always broken by the device having the greatest arc interrupting capacity, that is, the expulsion type circuit interrupting means 25.

The blade assemblage I1 comprises two tubular blade members 29 and 3| which are joined together at their outer end by a linkage, consisting of a pair of parallel link members 99 aflixed to the blade members through the agency of suitable pins 35. At their inner end, the blade members are joined together by a second linkage comprising a second pair of parallel link members 31. The lower end of each of the link members 31 and the left hand end of the lower blade member are engaged by the pivot pin 2| which extends through the opposed sides of the U shaped support IQ for the blade assemblage. The upper end of each of the two links 31 engages the left hand end of the upper blade member 9| through a pin 39.

Each of the blade members is provided with a suitable contact portion 4| at its outer end. The portion 4| aiilxed tothe lower blade member 29 is provided with a toothed section 49 (Fig. 2) which is adapted to cooperate with a similar too hed section 45 formed in one 01' the side portions ll of the jaw member 23, in order to permit the mechanical interconnecting of the two stationary insulators during the circuit closing operation, and the other portion 4| is provided with a smooth contact surface 49 for engaging the cooperating suriace 5| of the other side portion 41 of the jaw with a wiping connection.

During the normal operation of the switch, the entire blade assemblage I1 is swung from the open circuit position to a position where the contact portions ll of the two blade members are in proximity with the cooperating contact jaw 29. Then, the blade assemblage is held substantially stationary while the upper blade 2| is moved longitudinally relative to the lower blade 29. This movement causes the linkage connecting the outer end of the two blade members to be moved in such manner that the contact portions ll of the two blades are moved laterally away from each other. As a result the cooperating contact portions 49 and 5| of the upper blade 9| and one side of the jaws are caused to engage each other with a high pressure wiping action, and simultaneously with the wiping action of these contact portions, the toothed contact portions 43 and 45 of the lower blade 29 and the other side of the jaw are pushed into intimate engagement with one another thereby serving to mechanically interconnect the two stationary insulators 9 and 5. Through this arrangement, the cantilever stresses which are induced in those insulators during the normal operation of the switch are minimized.

In order that the circuit closing operation shall take place in two steps, a pair of angularly 01!- set crank members 53 and 55 are provided for actuating the blade assemblage l1. These oifset cranks are cast integral with one another into a single member 51 which is adapted to be rigidly aflixed to the cap portion I5 01 the rotatable insulator by suitable screws 59, and the cranks are operatlvely connected to the blade assemblage by means of a pair of tie-links 5| and 53. i

To accommodate the relative movement of the blade members and the associated actuating crank during the operation of the switch, each end of each of the cranks ii and 69 is provided with a universal joint means 55 for mechanically connecting each of the links with its actuating crank and with the blade assemblage. The right hand end of the lower link it engages an upstanding member 51 which is cast integral with the end portion 55 of the lower blade member 29, this upstanding portion acting substantially as a bell crank lever in order to permit the blade assemblage I! to be swung from one position to the other during the actuation of the switch. A tie-member 59 extends from the upstanding support 21 for the expulsion circuit interrupting device 25 to a point on the member 51 which coincides with the axis of rotation of the rotatable insulator and is held in that position by a suitable cap screw 1|. 'I'his tie 59 serves to give increased rigidity to the support means for the-expulsion circuit interrupting device.

A plate member I3 is bolted to the cap portion of the central insulator and extends from that insulator to the rotatable insulator 9. A circular openingfii is cut in the plate 19 for permitting the passage therethrough of the cylindrical base portion 15 of the crank casting 51. The opening and the base portion have cooperating bearing surfaces, and by this arrangement the engagement of the plate member 13 is caused to constitute a means for mechanically interconnecting the rotatable and the central insulators thereby reducing the stresses-induced in those insulators during the operation of the switch under adverse conditions. One of the switch terminals 14 is supported upon this plate memher and the other terminal is supported upon a suitable projection 11 which extends outwardly from the jaw member 23.

The expulsion type circuit breaker 25, as is shown particularly in Figs. through 8, includes a pair of interconnected tubular members 18 and 8| which define the outer walls of an arc passage 83 and a second passage 85 connecting therewith. A contact means 86 is mounted at the outer end of the tubular member I8 which defines the walls of the arc passage 83, and a rod shaped contact member 81 is provided for cooperating therewith, this rod member being adapted to move through the arc passage toward the contact means 85 during the circuit closing operation and to move through the arc passage away from the contact means dining the circuit opening operation. A weight means 88 is provided for actuating the rod contact 86. This weight is normallydisposed within the larger passage 85, and the walls of that passage serve as a guide therefor.

The inner surface of the walls of the arc passage 83 are preferably formed of hard fibre or some other material which is capable of evolving arc extinguishing gas when placed in proximity to an electrical arc, and the diameter of the passage is preferably not substantially greater than the diameter of the conducting rod 81 which moves therein during the operation of the interrupter. In order to assure that the electrical resistance through the expulsion type circuit interrupting device shall be maintained at a reasonably low value, the contact means 88 for engaging the rod at the outer end of the expulsion tube includes a plurality of fingers 8| which are biased toward each other by a pair of springs 83, as shown particularly in Figs. 7 and 8. These fingers 8| are retained in the position shown by an annular conducting member 85 which is threaded into the outer end of the main fiber tube. The central opening 81 within the conducting member 85 is of substantially the same cross sectional area as the arc passage itself 83, and it is flared at its outer end in order to facilitate the flow therethrough of the arc extinguishing gases. A hinged cap member 88 of insulating material is pivotally supported adjacent the outer end of the arc passage, and is biased to a position where it closes the outer end of the tube 18 by a suitable spring I83. The strength of this spring is such that the out-flowing gases from the arc passage 83 during the circuit interrupting operation may readily vent to the atmosphere.

The tubular member 18 which defines the walls of the arc passage 83 is mechanically connected to the guide tube 8| by a suitable metallic connecting member I84, the several members being provided with cooperating threaded portions. To assure good electrical contact between the guide tube 8|, which serves as one of the terminals of the expulsion device, four equally spaced contact fingers I88 are pivotally supported upon the connecting member I88 in such manner that they slidably engage the contact rod 81, a spring I88 similar to the springs 83 biases these fingers toward the contact rod. I

The guide tube 8| is of approximately the same length as the tubular means 18 which defines the walls of the arc passage 83 and is closed at its outer end by a suitable cap member I85 which is threaded thereon. A spring I81 is aflixed to this cap member at its inner side for reducing the shock force of the weight 88 during the circuit opening operation. The weight means itself includes a cylindrical member of heavy metallic material of slightly less diameter than the guide tube therefor. Openings I88 are cut in this member for retaining ball bearings III therein in order to minimize the friction between the guide and the weight, and the central portion of the weight is provided with a threaded opening 3 for mechanically engaging one end of the rod member 81.

A pair of arms 5 and 1 are supported upon the guide tube 8|, and each of these arms is provided with an outwardly projecting pin I I8 which is adapted to be engaged by the blade assemblage I1, during the operation of the switch, in order that the guide tube may be so moved that the weight 88 will cause the conducting rod to be moved from one position to the other. The entire expulsion circuit interrupting device engages the support therefor (the tie members 21 and 88) through suitable pivot pins H8.

The switch is shown in the closed circuit position in Fig. 1. To open the electrical circuit therethrough, the rotatable insulator 8 is turned in a clockwise direction (Fig. 2). The initial portion of this movement moves the center of the toggle linkage which is formed by the upper crank member 55 and the upper tie member 83 away from the center line of the switch and in so doing causes the upper blade member 3| to be moved longitudinally with respect to the lower blade member. This movement causes the blade members to move laterally toward each other and thereby effects a disengagement of the cooperating contact surfaces 43 and 48 of the blade assemblage and the contact jaw surfaces 45 and 5|. Upon further rotary movement of the actuating insulator 8, the center point of the toggle linkage formed by the lower crank member 53 and the lower tie member 6| is moved over the center line of the switch, and any additional movement beyond this point position causes the entire blade assemblage to be swung from the position shown in Fig. 1 toward the position shown in Fig. 3.

Due to the fact that when the switch is closed the center of gravity of the gravity actuating means for the expulsion circuit interrupter 25 biases the conducting rod 81 toward the cooperating contact means 88 disposed adjacent the outer end of the arc passage, the expulsion circuit interrupter is not moved toward the open circuit position during the switch opening operation until the upper blade member 3| engages the pin I I8 projecting outwardly from the upper bracket member I I5. As soon as this engagement occurs, however, the expulsion .circuit interrupter is caused to follow the blade assemblage toward the open circuit position, and when the center of gravity of that device has been shifted a sufficient amount, the weight 88 automatically begins to move the contact rod 81 toward the normal circuit position.

Once movement of the contact rod 81 is initiated, it progressively accelerates itself and the entire expulsion device swings from the position shown in Fig. 3 to the full open position shown in Fig. 4. The arcing horns |2I and I23 remain in engagement during a short portion of the circuit I v opening operation, but as soon as they are disengaged, the arc incident to the opening of-the circuit controlled by the switch is drawn therebetween. At the same time, an arc is being drawn within arc passage 83 formed in the tube 19. This second arc contacts the walls of the arc passage and causes the evolution ofa quantity arc extinguishing gas therefrom. In venting, this-gas flows outwardly with an expulsive action, and in a very short period of time effects the extinguishment of the are which is drawn within the arc passage. When in the open circuit position, the various elements of the switch are disposed as is shown in Fig. 4.

By causing the opening operation of the expulsion type circuit interrupter 25 to be brought about only after the blade assemblage I! has disengaged the cooperating contact jaw 23 therefor, the interruption of the circuit controlled by the switch is always brought about by that device which is best capable of extinguishing heavy current magnitude arcs.

The closingoperation is substantially the reverse of the opening operation. The rotatable insulator 9 is rotated counterclockwise from the position shown in Fig. 4 thereby swingably moving the blade assemblage I! in the direction of the contact jaw. As the blade assemblage nears the full on position, the lower blade member 29 engages the pin H8 which projects outwardly from the lower bracket arm H1 and moves the expulsion device 25 along with it toward the closed circuit position. The actuating linkages are so correlated that when the lower toggle linkage approaches the dead center position, the outer end of the blade assemblage is substantially in the normal closed circuit position. At this time, however, the upper linkage is a considerable distance (annular measurement) from the center line of the switch and during the final portion of the circuit closing operation it effects a longitudinal movement of the upper blade member 3i thereby producing a high pressure engagement of the cooperating contact surfaces.

Since the blade members engage the jaw means with a high pressure wiping engagement, any oxide or corrosion which might be formed between the cooperating contact surfaces are effectively cut through and a good electrical connection is assured between the blade and the contact jaw. By virtue of this, it is possible to reduce the normal current carrying capacity of the expulsion device 25 to a very small value, the normal distribution of current between the two parallel paths of the switch assuring that an excessive amount of current will not flow through the expulsion device when the switch is in the closed circuit position.

Through the provision of a slidable weight for afiectlng the actuations of the contact means of the expulsion circuit interrupter, the device is made completely enclosable, thereby assuring that water or ice will not interfere with its operation under adverse weather conditions. This is an important feature in adding to the reliability of operation of the switch, particularly since the blade assemblage is capable of operating even when heavily ice coated-the mechanism being so arranged that any ice which may be formed thereon is subjected to a tensional or a torsional stress during the normal operation of the switch.

From the foregoing, it will be seen that I have disclosed an improved disconnecting switch which is particularly suitable for use in applications where considerable amounts of power must be interrupted. In the preferred form, my improved switch includes a high current capacity but low arc extinction capacity circuit interrupting device and a high arc interrupting capacity device which is of low current carrying capacity, the two structures being electrically connected in parallel and being so arranged that the high current carrying capacity switch carries substantially all of the normal line current but is never called upon to open the circuit through the switch. In addition to this improved arrangement, I have disclosed the features of a gravity actuated expulsion type circuit interrupter which is so arranged that all of the moving parts are completely enclosed at all times.

In addition to the above, I have disclosed a novel arrangement for applying my improved expulsion type circuit interrupter to disconnecting switches generally, and have shown how the normal movement of the blade can be utilized for effecting the actuation of the contact means of the expulsion interrupter.

While in the foregoing, I have described the features of a device wherein the auxiliary circuit interrupting device provides a metallic conducting circuit electrically in parallel with the high current capacity interrupter, formed by the blade assemblage and the cooperating contact means therefor, it is to be understood that this arrangement is but one of those which may be used. The objects of the invention may quite as readily be accomplished by the provision of a structure which includes means for assuring that any are which may be established during the circuit opening operation shall be caused, eventually, to exist between one of the terminals of the auxiliary circuit interrupting device and one of the main switch terminals. Any arrangement meeting this requirement effects the desired sequence of operation and assures that all arcs shall be extinguished by that portion of the device which is best fitted for accomplishing that extinction.

As an illustration the above requirement may be fulfilled through the provision of a structure .wherein the auxiliary circuit interrupting device,

when in the closed circuit position, has a terminal disposed in close proximity to, but not actually contacting, the contact means which cooperates with the movable blade portion of the high current capacity interrupter. During the initial portion of the circuit opening operation of such a structure, the blade means for the main current carrying means is moved, toward the open circuit position, thereby drawingan arc between one end of the blade and its cooperating contact. The air gap (which is a measure of the arc length) produced by this circuit opening movement of the blade means will soon become suiiiciently large to create an impedance path for the are which is of greater magnitude than the path through the auxiliary interrupter, and as a result a break down between the contact means for the blade assemblage and the adjacent portion of the auxiliary circuit interrupting device will take place, the initially formed are between the blade and its cooperating contact means being thereby extinguished. By properly proportioning the air gap in the circuit through the auxiliary interrupter the transfer of the are from the main current-carrying path to the auxiliary currentcarrying path may be caused to take place at any desired point in the circuit opening operation.

By providing an arcing horn as has been done in the above described preferred embodiment of my invention, arcing between the main blade assemblage and its cooperating contact means is 75 prevented at all times. The objects of the invention may, however, as pointed out in the fore going, be accomplished in a device wherein the outer terminal of the auxiliary contact means does not actually contact the cooperating contact for the main bridging means, and it is my desire that the accompanying claims shall cover such a device, the language a conducting path in parallel with the main current carrying path being intended to cover a device wherein the auxiliary current carrying path may have an air gap therein, the are initially drawn by the blade assemblage breaking down across this air gap so as to cause all of the current flowing through the device to flow through the auxiliary circuit interrupter during the progress of the circuit opening operation.

While in accordance with the patent statutes, I have disclosed the foregoing details of a preferred embodiment of my' invention; it is to be understood that many of these details are merely illustrative and that variations in their precise form will be both necessary and desirable in certain instances; I desire, therefore, that the language of the accompanying claims shall be accorded the broadest reasonable construction, and that my invention shall be limited only by what is expressly stated therein and by the prior art.

I claim as my invention:

1. In an electrical switch, a pair of spaced insulator columns, conducting means mounted on each of the columns, a swingably supported blade for bridging the conducting means to provide an electrical circuit therebetween, an arc extinguishing device mounted in proximity to the blade, means operable to actuate the blade into and-out of engagement with at least one of the conducting means, said are extinguishing device including relatively movable conducting members for providing a conducting path in parallel with the current carrying path provided by the blade when the switch is in closed circuit position, and means carried by said are extinguishing device adapted to be engaged by said blade upon movement of the latter out of engagement with the said one contact for separating said relatively movable conducting members to establish an arc therebetween, said means carried by said are extinguishing device being operative upon further movement of said blade toward the full open position to separate the arc extinguishing device a substantial distance from at least one of said conducting means to thereby provide an air gap sufiicient to withstand high voltage.

2. In an electrical switch, a pair of spaced conducting members, a blade adapted to bridge the conducting members when the switch is in closed circuit position, a rotatable insulator, means operable in response to rotation of the insulator to actuate the blade into and out of engagement with at least one of the conducting means, and means mounted in proximity to the blade for extinguishing the are which is formed incident to the opening of the circuit controlled by the switch, the arc extinguishing means including a closure, relatively movable contact members within said closure for providing a conducting path in parallel with the current carrying path provided by the blade at least during each opening movement of the switch, means carried by the arc extinguishing means disposed to be engaged by the blade when it is actuated, to efiect a movement of the closure, the means carried by the arc extinguishing means and the blade being arranged to provide a lost motion, and means automatically actuable in response to movement of said closure to a given predetermined position to effect the separation of said relatively movable contact members and automatically actuable in response to movement of the closure to another predetermined position to effect engagement of said relatively movable contact, said blade during its opening movement being adapted to actuate said are extinguishing means a substantial distance from at least one of said spaced conducting members to thereby provide an air gap in said conducting path capable of withstanding high voltage.

3. In an electric switch, a stationary contact, a blade member movable into and out of engagement with said stationary contact, means for actuating said blade member, an arc extinguishing device movable into and out of engagement with said stationary contact, said are extinguishing device comprising a terminal adapted to releasably engage said stationary contact, a pair of separable contacts and means automatically operative in response to movement of said are extinguishing device toa predetermined position for actuating said separable contacts to open position, and means carried by said are extinguishing device disposed to engage said blade member following the latters disengagement from said stationary contact for, actuating said are extinguishing device to said predetermined position and for further actuating said arc extinguishing device to a position disconnected from said stationary contact to thereby provide an air gap between said stationary contact and said are extinguishing device capable of withstanding high voltage. I

4. In an electric switch,.a stationary contact, a blade member movable into and out of engagement with said stationary contact, means for actuating said blade member, an arc extinguishing device movable into and out of engagement with said stationary contact, said are extinguishing device comprising a terminal adapted to releasably engage said stationary contact, a pair of separable contacts and means automatically operative in response to movement of said are ex tinguishing device to a predetermined position for actuating said separable contacts to open position, and means carried by said are extinguishing device disposed to engage said blade member following the latters disengagement from said stationary contact for actuating said are extinguishing device to said predetermined position and for further actuating said are extinguishing device to separate said terminal a substantial distance from said stationary contact to provide an air gap suflicient to withstand high voltage, said automatically operative means for actuating said separable contacts being disposed to bias said terminal into engagement with said stationary contact when said blade member is in the closed position.

5. In an electric switch, a stationary contact, a blade means swingable into and out of engagement with said stationary contact to open and to close the electrical circuit through said switch, actuating means for said blade means, and means of greater arc extinguishing capacity than said blade means for extinguishing the are which is formed incident to each opening operation of said switch, said are extinguishing means being mounted in proximity to said blade means and comprising a tubular member swingable into and out of engagement with said stationary contact, relatively movable contact means which provides a conducting path in parallel with 'said blade means at least during each opening operation of said switch, a slidably supported weight which normally biases said tubular means into engagement with said stationary contact, and means carried by said are extinguishing means disposed to be engaged by said blade means during each opening operation of said switch to cause said tubular means to be moved out of engagement with said stationary contact and to cause said slidable weight to move to a position where it biases said tubular means away from said stationary contact, said means carried by said are extinguishing means and said blade means being arranged to provide for a lost motion, said slidable weight when moving to said last mentioned position effecting the separation of said relatively movable contact means.

6. In an electric switch, a stationary contact, a blade means swingable into and out of engagement with said stationary contact to open and to close the electrical circuit through said switch, actuating means for said blade means, and means of greater are extinguishing capacity than said blade means for extinguishing the arc which is formed incident to each opening operation of said switch, said arc extinguishing means being mounted in proximity to said blade means and comprising a tubular closure having at least one terminal positioned adjacent one end thereof, said closure being supported for swingable movement to an open and to a closed circuit position in which latter position said terminal member engages said stationary contact, relatively movable contact means which provides a conducting path in parallel with said blade means at least during each opening operation of said switch, means automatically actuable to move said relatively movable contact members into or out of engagement with one another when said tubular member is moved from one'of said positions to the other, and means carried by said arc extinguishing means disposed to be engaged by said blade means when it is actuated, to eflect a switching operation, said means carried by said are extinguishing means and said blade means being arranged to provide for a lost motion.

'7. In an electric switch, a stationary contact, a blade means movable into and out of engagement with said stationary contact to open and to close the electrical circuit through said switch, actuating means for said blade means, and means of greater arc extinguishing capacity than said blade means for extinguishing the are which is formed incident to each opening operation of said switch, said arc extinguishing means being mounted in proximity to said blade means and comprising a tubular closure which is supported so as to be movable into and out of engagement with said stationary contact, relatively movable contact means which provides a conducting path in parallel with said blade means at least during each opening operation of said switch, means automatically actuable when said tubular closure is moved out of engagement with said stationary contact to effect the separation of said relatively movable contacts, and means carried by said tubular closure and projecting into the path of movement of said blade means and adapted to be engaged by said blade means during each opening operation of said interrupter to cause said tubular closure to be moved out of engagement with said stationary contact in response to movement of said blade means, said last-mentioned means being so arranged that the movement of said tubular closure out of engagement with said sta tionary contact takes place at a time subsequent to the disengagement of said stationary contact by said blade means.

8. In an electric switch, a stationary contact, a blade means swingable into and out of engagement with said stationary contact to open and to close the electrical circuit through said switch, actuating means for said blade means, and means of greater are extinguishing capacity than said blade means for extinguishing the arc which is formed incident to each opening operation oi said switch, said are extinguishing means being mounted in proximity to said blade means and comprising a tubular closure supported for swingable movement to an open and to a closed position, a terminal which is supported on said closure, said terminal being moved into engagement with said stationary contact when said closure is moved to the closed circuit position and being moved out of engagement with said stationary contact when said closure is moved to the open circuit position in order to assure the existence of an air gap in the electrical circuit of said switch when said switch is in the open circuit position, relatively movable contact means which provides a conducting path in parallel with said blade means at least during each opening operation of said switch, means automatically actuable to move said relatively movable contacts out of engagement with one another when said closure is moved from the closed circuit position to the open circuit position and to effect the reengagement or said contacts when said closure is moved from the open circuit position to the closed circuit position, and means carried by said tubular closure and projecting into the path of movement oi. said blade means and adapted to be directly engaged by said blade means during each opening operation of said switch to cause said tubular closure to be moved from the closed circuit position to the open circuit position in response to movement of said blade means, said last-mentioned means including means whereby the movement 01 said closure to the open circuit position is caused to take place only after said blade means has disengaged said stationary contact.

9. In an electric switch, a pair of spaced contacts, a blade means of high current carrying capacity but low arc extinguishing capacity adapted to bridge said spaced contacts when said switch is in the closed circuit position, means for suporting said blade means for movement into and out of engagement with at least one of said spaced contacts to open and to close the electrical circuit through said switch, and means of greater arc extinguishing capacity than said blade means for extinguishing the are which is formed incident 01' each opening operation of said switch, said are extinguishing means being mounted in proximity to said blade means and comprising a tubular closure which is supported for movement to an open and to a closed circuit position, a terminal positioned adjacent one end of said closure, said terminal engaging said stationary contact when said tubular means is in the-closed circuit position and being moved out of engagement with said stationary contact when said tubular means is moved to the open circuit position, relatively movable contact means which provides a conducting path in parallel with said blade means at least during each opening operation of said switch, means automatically actuable to move said relatively movable contacts into engagement with each other when said tubular closure is moved from said open circuit to said closed circuit position and to move said relatively movable contacts out of engagement with each other when said tubular closure is moved from said closed circuit to said open circuit position, and means carried by said tubular closure and projecting into the path of movement of said blade means and adapted to be directly engaged by said blade means during each operation of said switch in order that said tubular closure shall be moved to the open and to the closed circuit position in response to the movement of said blade means into and out of engagement with said stationary contact.

10. In an electric switch, a pair of spaced conducting members, a swingably supported bridging means movable into and out of engagement with at least one of said conducting members to open and to close the electrical circuit through said switch, and actuating means for swinging said bridging means to the open and to the closed circuit position, said swingable bridging means comprising relatively movable contacts, a tubular means for defining an arc passage wherein at least one of said contact means is adapted to move, at least a portion of said tubular means being lined with a material that is capable of evolving an arc extinguishing gas when placed in proximity to an electric arc, means automatically actuable to efiect the separation of said relatively movable contacts only after said tubular means has swung a predetermined distance from the closed circuit position toward the open circuit position and which is automatically actuable to effect the reengagement of said relatively movable contacts when said tubular means is swung a predetermined distance from said open circuit position toward said closed circuit position, said automatically actuable means being mechanically connected to said movable contact member within said bridging means.

11. In an electric switch, a pair of spaced conducting members, a swingably supported bridging means movable into and out of engagement with at least one of said conducting members to open and to close the electrical circuit through said switch, and actuating means for swinging said bridging means to the open and to the closed circuit position, said swingable bridging means comprising a pair of connecting tubular closures one of which defines an arc passage and the other of which defines a guide passage, relatively movable contact means at least one of which is movable through said arc passage during the operation of said switch, and means automatically actuable to move said relatively movable contacts into engagement with each other when said bridging means is swung from the open circuit to the closed circuit position and out of engagement with each other when said bridging means is swung from the closed circuit to the open circuit position, said contact actuating means including a weight supported for slidable movement in said guide passage, said weight being so arranged with respect to the support point for said swingable bridging means that it serves to bias that device toward the open circuit position when said switch is in that position and to bias said bridging means toward the closed circuit position when said switch is in that position, said automatically actuable means being carried in said guide passage and being mechanically connected to said contact member movable through sa d are passage.

12. The combination with an air break switch having a stationary contact, a blade mounted for swinging movement into and out of engagement with said contact, and means for actuating said blade of an arc extinguishing device comprising a tubular member having a terminal at one end thereof, said tubular member being mounted for swinging movement about a fixed pivot for moving said terminal into and out of engagement with said stationary contact, a pair of separable contacts within said tubular member, means operative in response to the movement of said tubular member to a predetermined position for actuating said separable contacts to the open position, and a lost motion coupling between said tubular member and said blade member for swinging said tubular member to open position in accordance with movement of said blade member, said lost motion coupling delaying movement of said tubular member until said blade member has disengaged from said stationary contact, said terminal member maintaining engagement with said stationary contact until said separable contacts have separated.

13. The combination with an air break switch having a pair of spaced insulators, a fixed contact on one of said insulators, a blade pivotally mounted on the second insulator and means for swinging said blade into and out of engagement with said fixed contact of conducting means normally in parallel circuit relation with said blade, said conducting means comprising a support member pivotally mounted on said second insulat-or adjacent said blade for swinging movement into and out of engagement with said fixed contact, separable contacts carried by said support member, means responsive to the movement of said support member to a predetermined position for separating said separable contacts, means responsive to and following a predetermined movement of said blade in the circuit opening direction for moving said support member out of engagement with said fixed contact and for separating said contact andsaid support memher a substantial distance to provide an air gap sufiicient to withstand a high voltage, said support member maintaining electrical engagement with said fixed contact until said support member' has moved a distance sufficient to cause said separable contacts to open.

HERBERT J. CRABBS.

Images