US3222477A

US3222477A - Tubular circuit interrupter with mechanical release of arc drawing terminal within the tube

Info

Publication number: US3222477A
Application number: US210093A
Authority: US
Inventors: Sigurd I Lindell
Original assignee: S&C Electric Co
Current assignee: S&C Electric Co
Priority date: 1962-07-16
Filing date: 1962-07-16
Publication date: 1965-12-07
Anticipated expiration: 1982-12-07

Description

S. l. LINDELL Dec. 7, 1965 TUBULAR CIRCUIT INTERRUPTER WITH MECHANICAL RELEASE OF ARC DRAWING TERMINAL WITHIN THE TUBE 9 Sheets-Sheet 1 Filed July 16, 1962 IN V EN TOR.

SIC-EURO I. LINDELL Dec. 7, 1965 s. 1. LI ELL 3,222,477

TUBULAR CIRCUIT INTERR ER WITH MECHANICAL RELEASE OF A DRAWING TERMINAL WITH THE TUBE 9 Sheets-Sheet 2 Filed July 16, 1962 9 Sheets-Sheet 5 I. LINDELL N RUPTER WITH MECHANIC A DRAWING TERMINAL UBE Dec. 7, 1965 TUBULAR CIRCUIT I RELEASE OF WITHIN THE '1 Filed July 16, 1962 Dec. 7, 1965 .LINDELL 3,222,477

TUBULAR CIR UPTER WITH MECHANICAL RELEA RAWING TERMINAL HIN THE TUBE Filed July 16, 1962 9 Sheets-Sheet 4.

Z 1 0 6 01m O I w 1 I I V 5 m m m V///// S. l. LINDELL Dec. 7, 1965 TUBULAR CIRCUIT INTERRUPTER WITH MECHANICAL RELEASE OF ARC DRAWING TERMINAL WITHIN THE TUBE 9 Sheets-Sheet 6 Filed July 16, 1962 7, 1965 s. l. LINDELL TUBULAR CIRCUIT INTERRUPTER WITH MECHANICAL RELEASE OF ARC DRAWING TERMINAL WITHIN THE TUBE 9 Sheets-Sheet 7 Filed July 16, 1962 Dec. 7, 1965 s. I. LINDELL TUBULAR CIRCUIT INTERRUPTER WITH MECHANICAL RELEASE OF ARC DRAWING TERMINAL WITHIN THE TUBE 9 Sheets-Sheet 8 Filed July 16, 1962 5 M 5 1 83 5 M 1 M 3 3 3 0 0 9 M M 5 5 3 M i 11 5 7 0 F 8 4 r 4 41 w l 1 9 4 9 1 5 7 1 u a u. 5 W7 0 1 1 a m. M 1 3 P 1. q 4 F m T 6 1 WNW iik i n l I NW (IFNIAM u fl Q 0 l 1 g F 4/ /0 j w 1/ 2 a i i w 5 3 f 4 M M 0 1 3 TUBULAR CIRCUIT INTERRUPTER WITH MECHANICAL RELEASE OF ARC DRAWING TERMINAL WITHIN THE TUBE Dec. 7, 1965 s, I LlNDELL 3,222,477

Filed July 16, 1962 9 Sheets-Sheet 9 m; .m 113 Q Q: 2 4 1:1

United States Patent ware Filed July 16, 1962, Ser. No. 210,093 30 Claims. (Cl. 200-414) This invention relates, generally, to the construction of circuit interrupters and it has particular relation to dropout fuses arranged and adapted to open the circuit and dropout as a result of an operation other than the blowing of their fusible elements. A dropout fuse construction to which this invention is particularly applicable is shown in US. Patent No. 2,599,186, issued June 3, 1952, to S. I. Lindell.

It is sometimes desirable to cause a fuse of the kind shown in the above patent to interrupt the current flow and then to dropout and isolate the circuit in which it is connected in response to the operation of means other than the blowing of its fusible element. It is well understood that the fusible element has a certain timecurrent characteristic and it may become necessary to isolate the circuit under circumstances where the fusible element would not be responsive from either a time or a current standpoint. The speed of response may be too low or the current required may be too high. An example is found where the circuit is to be opened in which the fault current flow may be of insuflicient magnitude initially to cause the fusible element to blow, or to blow within a short enough interval, to obtain the required circuit isolation. Such a situation may exist when one or more turns of the windings of a transformer protected by the fuse become short circuited and the fault must progress to a great extent before the current rises to a magnitude sufficient to blow the fuse. The fault current flow often can be detected only by a differential protective arrangement in which a differential relay is responsive to the fault and can be employed to trigger the fuse of this invention. This causes it to interrupt the current flow and isolate the circuit without blowing the fusible element. Other applications of the present invention will be apparent to those skilled in the art.

Accordingly, among the objects of this invention are: To provide for triggering one or more dropout fuses to operate them by means other than by blowing of their fusible elements without interfering with the are interrupting capabilities of the fuses to interrupt load currents, transformer exciting currents or fault currents of magnitude not exceeding the rated short circuit interrupting capability of the fuses; to provide for such operation whether or not a fusible element is employed to perform its normal function of interrupting the current flow; to provide a fuse construction for this purpose having a minimum restriction with respect to expulsion of extinguishing vapor (gas) and are products from the bore of the fuse so as not to reduce its interrupting rating or its capacity to interrupt high short-circuit current; to provide positive, shock and vibration proof latching and positive measured contact pressure on movable releasable contacts established through resilient members actuated and sprung through mechanical advantage means such as wedge means by a slidable control member which is restrained in latched position by spring means; to provide control means for releasing the contact pressure as a result of longitudinal movement of an operator from a discharge end of the dropout fuse; to provide for latching and control of the 3,222,477 Patented Dec. 7, 1965 latching of the mechanical and electrical connection to an are drawing terminal that may be the releasable fusible element terminal in a positive manner and through the discharge end of the device, such as a dropout fuse, with the arrangement being such that the gripping jaws are unlatched and moved apart to free the terminal in a positive manner so that it can be retracted by the retraction spring of the device without any added opposing friction due to the previous latching engagement with the terminal; to provide for releasing the latch means holding the terminal against movement by a momentary application of a blow or a force through a closure or lid at the exhaust or discharge end of the device; to provide for drawing the terminal into operative position in the device and to tension the operating spring by application of a tension to the terminal endwise of the device through its exhaust end; to provide for latching the terminal in operative position by mechanical latch means also having capability of carrying the current flowing through the device under normal operating conditions or fault current operating conditions; to provide for checking the gripping force and force required to operate the terminal releasing member or actuator externally of the device before the mechanism is assembled therein and for assembling it in operative position in the device without loss of dimensional or force adjustments; to employ a pair of oppositely laterally movable jaws for gripping the terminal and for guiding the movement of the terminal and of the jaws to center the terminal between the jaws for equalizing the restraining pressure applied thereby and permitting the jaws to be withdrawn positively from the terminal to release it completely; and to employ for the latch members for holding the terminal against movement and making contact therewith relatively long and resilient beam members which can be positively anchored at their ends remote from the latch jaws and which can be controlled so as to provide measured gripping and contact forces as well as controlled mechanical release forces and in addition to provide adequate resiliency so as to avoid critical dimensions and high operating forces that may be encountered if other anchoring means extending crosswise inside the exhaust end of the device and of adequate current carrying capacity were used.

In the drawings:

FIG. 1 is a view showing a typical installation of triggered fuse constructions in accordance with this invention, the view showing the vertically extending supports with the insulator bases mounted thereon, one of the assemblies showing the construction at the lower end of the dropout fuse, and showing external trigger operating mechanism for one of the units together with means for commonly operating them to trigger all of the dropout fuse constructions.

FIG. 2 is a view, in side elevation, of the construction shown in FIG. 1 with the dropout fuse embodying the present invention mounted on laterally extending insu lators from a support.

FIGS. 3-A, 3-B, 3-C and 3-15 (FIGS. 3-C and 3E being at an enlarged scale) placed end to end in the order named show certain details of construction in vertical longitudinal section in a dropout fuse embodying the present invention; FIG. 3-C showing the fusible element terminal latch means in the latched position and FIG. 3-D corresponding to FIG. 3C but showing the fusible element terminal latch means in the unlatched position with the fusible element terminal released and moving upwardly to interrupt the circuit accompanied by release of the fuse tube latch release means to permit the dropout fuse to swing downwardly to the open position.

FIG. 4 is a horizontal sectional view, at a reduced ice scale, taken generally along the line 44 of FIG. 3-E.

FIG. 5 is a horizontal sectional view, at a reduced scale, taken generally along the line 5-5 of FIG. 3-C.

FIG. 6 is a horizontal sectional view, at a reduced scale, taken generally along the line 66 of FIG. 3-C. FIG. 7 is a view, at an enlarged scale, of the external trigger operating mechanism that is mounted at the lower end of each of the dropout fuses, the mechanism being shown in the non-operated position and the sleet hood being shown in section in order to illustrate more clearly certain of the parts of the mechanism.

FIG. 8 is a sectional view taken generally along the line 8-8 of FIG. 7.

FIG. 9 is a view, similar to FIG. 7, but showing the trip arm impacting the lower end of the operator to trigger the fuse release mechanism with the actuating lever being shown in the fully operated position to which it is moved for actuating the trip arm.

FIG. 10 is a view, similar to a portion of FIG. 3-C, and shows a modified construction for the trigger means.

FIG. 11 is a horizontal sectional view, taken generally along the line 1111 of FIG. 10.

FIG. 12 is a view, similar to FIG. 10, but showing the fusible element terminal latch means in the unlatched position with the fusible element terminal moving upwardly for the purpose described above in connection with FIG. 3-D.

Referring now particularly to FIGS. 1 and 2 of the drawings, it will be observed that the reference character 10 designates, generally, a dropout fuse construction which is intended for polyphase operation. For example, the dropout fuse construction 10 can be employed for controlling the connection of a three phase circuit to a suitable alternating current power supply circuit. While the dropout fuse construction 10 can be employed on circuits operating at various voltages, it is intended particularly for operation in connection with circuits operating at voltages of the order of 34.5 kv. and above depending upon the requirements of the system. It will be understood that three dropout fuse constructions 10 are employed for a three phase system and, since they are of identical construction, a description of one will sufiice for a description of all of them.

Each dropout fuse construction 10 includes a support 11 in the form of a channel base that is arranged to be supported suitably (by means not shown) so as to extend generally vertically. The support 11 carries upper and

lower insulators

12 and 13 in laterally extending relation. At the distal ends of the

insulators

12 and 13 upper and

lower line terminals

14 and 15, respectively, are mounted. They are interconnected by a dropout fuse that is indicated, generally, at 16. The details of construction of the dropout fuse 16 are generally similar to the construction shown in the patent above referred to. Accordingly, only a general description thereof will be set forth herein.

The dropout fuse 16 includes a fuse tube 17 of suitable insulating material which carries an upperfuse tube terminal, shown generally at 18, in contact engagement with the upper line terminal 14. The fuse tube 17 also has a lower fuse tube terminal, shown generally at 19, which is suitably connected to and mounted on the lower line terminal 15. A latch arm 20 on the upper line terminal 14 serves to latch the upper fuse tube terminal 18 in contact engagement therewith. The lower fuse tube terminal 19 is pivoted, as indicated at 21, on the lower line terminal 15. For a complete understanding of the manner in which the upper fuse tube terminal 18 is latched to the upper line terminal 14 and the lower fuse tube terminal 19 is pivoted to the lower line terminal reference can be had to US. Patent No. 2,578,255, issued December 11, 1951, to S. I. Lindell. However, it 'will be understood that other latching and pivot means can be employed as may be desired.

In order to move the latch arm 20 to the unlatching position, a flange Z4 is provided on the lower end of a slidable unlatching tube 25. As set forth in the patents above referred to, provision is made on blowing of a fusible element for moving the unlatching tube 25 upwardly to lift the latch arm 20 for the purpose of unlatching the upper fuse tube terminal 18 from the upper line terminal 14 and permitting the dropout fuse 16 to pivot at 21 on the lower line terminal 15 to an open position. The unlatching tube 25 can be moved upwardly manually by causing an arm 26 on a pull ring 27 to lift the same. The pull ring 27 is pivoted at 23 on the upper fuse tube terminal 18 and the arrangement is such; that, when the prong of a live line stick is inserted in the pull ring 27 and sufficient force is applied thereto, the; pull ring 27 is rotated about its pivot 28 to cause the arm 26 to engage the underside of the flange 27 and move the; unlatching tube 25 upwardly and at the same time swing-- ing the latch arm 20 to the unlatched position.

The lower fuse tube terminal 19 has an eye member 29 mounted thereon for receiving a prong of a live line stick to permit application of the dropout fuse to the lower line terminal 15 in conventional manner. Thereafter, the prong of the live line stick is inserted in the pull ring 27 and the dropout fuse 16 is swung to the position shown in FIG. 2 where the upper fuse tube terminal 18 is in contact engagement with the upper line terminal 14 and is latched in this position by the latch arm 20. A resilient bumper 30 is carried by the lower line terminal 15 for cushioning the downward swinging movement of the dropout fuse 16 after it has been released by operation of the latch arm 20 in the manner described.

As pointed out above, it is desirable to trigger the operation of the dropout fuse 16 under certain circumstances when its fusible element is not required to blow and yet it is desired to take advantage of the circuit inter-- rupting capabilities of the dropout fuse 16 for opening the: circuit. For this purpose an external trigger operating; mechanism, shown generally at 33 in FIGS. 1 and 2, is provided.

The details of construction of the external trigger operating mechanism 33 are the invention of William A. Gussow and are disclosed and claimed in Patent No. 3,184,567, issued May 18, 1965. It will be understood that other external trigger operating mechanism than that indicated at 33 can be employed in connection with the trigger means embodied in the dropout fuse 16, as described hereinafter, and that the particular mechanism 33 is shown and described herein for illustrative purposes.

A part of the external trigger operating mechanism 33 is mounted on a support bracket 34 in the form of a plate which is mounted on the distal end of the lower insulator 13 of each fuse construction 10 between it and the respective lower line terminal 15. Extending outwardly from the support bracket 34 is a sleet hood 35 which overlies a major portion of the external trigger operating; mechanism 33 and is spaced, as indicated at 36 in FIG. 1,. from the juxtaposed side of the lower line terminal 15 a sufficient distance so that ice does not form therebetween. The trigger operating mechanism 33 includes a rotatably mounted trip arm 37, a portion of which extends: below the sleet hood 35 in the non-operated position andi the details of construction of which are shown in FIGS. 7,. 8 and 9 and described hereinafter. For operating the trip arm 37 an actuating lever 38 is provided. It is mounted.

for rotation with the distal end of a rotatable insulator 39 which extends generally parallel to and below the lower insulator 13 and is mounted in a bearing 49 that is carried by an extension plate 41 on the lower end of the support 11. An operating arm 42 extends radially from the base of the rotatable insulator 39 for rotating it between stop pins 43-4-3 which extend forwardly from the extension plate 4-1 and into the path of movement of the operating arm 42.

When a polyphase dropout fuse construction is employed, for example a three phase installation, three dropout fuses 16 are used and provision is made for effecting their simultaneous operation in order to dropout and clear all three phases at the same time. For this purpose each of the operating arms 42 is pivotally connected at 44 to an interphase rod 45 and provision is made for longitudinally moving it to rotate simultaneously the three rotatable insulators 39 for operating the three external trigger operating mechanisms 33. Any suitable means can be employed for moving the interphase rod 45 endwise. Preferably provision is made for moving it with a snap action. For example, it can be connected pivotally at 46 to one arm of a bell crank 47 which is pivoted at 48 on a suitable support 49 in the form of a channel base. The other arm of the bell crank 47 is pivotally connected at 50 to a pull rod 51 that is connected at its lower end pivotally at 52 to an arm 53 of a spring operator that is indicated, generally, at 54. A handle 55 permits manual cocking of an operating spring in the spring operator 54. The spring in the spring operator 54 can be triggered by any suitable means, such as by differential relay means or by a system such as disclosed in US. Lindell et al. Patent No. 3,116,- 391, issued December 31, 1963. Such current responsive means effects a release of the cocked spring to rotate the arm 53 with a snap action and effect a corresponding accelerated movement of the interphase rod 45 which is accompanied by a corresponding high speed rotation of the several rotatable insulators 39 and corresponding movement of the actuating levers 38 carried thereby. On return movement of the handle 55 the interphase rod 45 is returned to the position shown in FIG. 1 of the drawings. As will appear hereinafter, a trip free connection is provided between each actuating lever 38 and the trip arm 37 operated thereby. Accordingly, after each actuating lever 38 has caused the respective trip arm 37 to trigger the dropout fuse 16 associated therewith, the construction is such that the trip arm 37 is promptly retrieved to its non-operated position and out of the path of the dropout fuse 16 so that it can fall freely to the open position.

Reference now will be had to FIGS. 3-A, 3-B, 3-0 and 3-E of the drawings. It will be recalled that these figures should be placed one above the other in the order named in order to provide a complete longitudinal sectional view of the details of construction of the dropout fuse 16. Also, it will be understood that 'FIGS. 3-C and 3-E are shown at a larger scale than FIGS. 3A and 3-B in order to show more clearly the details of construction of the fusible element terminal latch means forming a part of the trigger means that is operated by the external trigger operating mechanism 33 to release the dropout fuse 16 from its latched connection to the upper line terminal 14 and permit it to fall to the open position. Here it will be observed that the fuse tube 17, which may be formed of a phenolic condensation product, is provided with an insulating liner 57 that may be formed of high strength material such as fiber. Within the liner 57 is a stack of cakes 58 of boric acid or similar arc extinguishing material which are held in place by a layer 59 of cement. The cakes 58 are apertured to provide a longitudinally extending bore 60 therethrough. Extending and endwise movable through the bore 60 in the cakes 58 of arc extinguishing material is a rod-like terminal 61 which is provided at its upper end with a cylindrical contact 62 that is engaged by contact fingers 63 under substantial pressure exerted by a garter spring 64. The contact fingers 63 are secured to a contact fitting 65 to which electrical connection is made by a connector tube 66 which extends upwardly along the inner surface of the fuse tube 17 and is connected at its upper end to the upper fuse tube terminal 18. This arrangement provides a direct connection between the upper fuse tube terminal 18 and the rod-like terminal 61 through which th current normally flows.

In order to withdraw the rod-like terminal 61 through the bore 60 and extinguish the arc therein, the rod-like terminal 61 is provided with an extension rod 67 which is connected to the contact 62 at its lower end while its upper end is connected to a cable connector assembly 68 that is flexible in nature and is trained over a pulley 69. The other end of the cable connector assembly 68 is connected to a strap 70 which is connected at 71 to the contact fitting 65. This arrangement provides a connection between the rod-like terminal 61 and the contact fitting 65 after the contact 62 is moved out of engagement with the contact fingers 63. The pulley 69 is carried by a clevis 72 which depends from a yoke 73 that is carried by a tube end fitting 74 that is located at the upper end of the compression tube 75 which is slidable within the connector tube 66 and which has an annular fitting 76 at its lower end against which the coil compression spring 77 reacts. The lower end of the coil compression spring 77 reacts against the upper side of the contact fitting 65 and it serves to bias the compression tube 75 upwardly. It will be understood that the compression tube 75 and parts movable therewith constitute fuse tube latch release means, indicated generally at 78, with the arrangement being such that, when the rod-like terminal 61 is released, the coil compression spring 77 moves the compression tube 75 upwardly carrying with it the pulley 69. As a result the rod-like terminal 61 moves upwardly at a speed which is twice that of the speed of upward movement of the compression tube 75. The compression tube 75 is telescoped within the unlatching tube 25 and at the end of its upward movement the tube end fitting 74 engages the upper end 25 of the unlatching tube 25. It will be recalled that this movement is accompanied by upward movement of the flange 24 which lifts the latch arm 20 and unlatches the upper fuse tube terminal 18 from the upper line terminal 14 and permits the dropout fuse 16 to rotate about the pivot 21 to the open position.

Referring now particularly to FIG. 3-C it will be observed that a metallic annular fitting 80 is threaded into the lower end of the liner 57. Secured to the lower end of the fitting 80 is a metallic exhaust tube 81 which extends downwardly over the inner surface of the fuse tube 17 where it is joined through a spacing ring 82, FIG. 3-E, to the inner surface of the lower fuse tube terminal 19 which is generally cylindrical in configuration and which extends over the outer surface of the lower end of the fuse tube 17 and projects downwardly therebelow. It will be understood that trunnions are provided on the lower fuse tube terminal 19 by means of a suitable fitting as described in more detail in US. Patent No. 2,578,255, issued December 11, 1951, to S. I. Lindell.

Referring again to FIG. 3-C, it will be observed that the lower end of the rod-like terminal 61 has connected thereto one end of a fusible element that is indicated, generally, at 83 and which serves to restrain upward movement of the rod-like terminal 61 under the influence of the coil compression spring 77. The fusible element 83 is connected at its lower end to a fusible element terminal that is indicated, generally at 84 and provision is made for restraining it and for releasing it that will be described presently. The fusible element 83 may include a fuse Wire 85 in the form of a helical coil of silver wire surrounding a strain wire 86 of high strength metal such as a nickel chromium alloy. It will be understood that it is conventional to connect a fusible element terminal, similar to the fusible element terminal 84, to the metallic annular fitting 80 or to the upper end of the metallic exhaust tube 81. When such a construction is employed and the rod-like terminal 61 is to be released for operating the dropout fuse 16, it is necessary that the fusible element 83 blow. When this takes place, the rod-like terminal 61 moves upwardly through the bore 60 in the cakes 58 of solid arc extinguishing material and the arc incident to the blowing of the fusible element 83 is drawn between the lower end of the rod-like terminal 61 and the upper end of the fusible element terminal 84 or some part of the metallic annular fitting 80 or of the metallic exhaust tube 81. The arc products flow downwardly through the metallic exhaust tube 81 which provides an exhaust channel that discharges to the atmosphere through the lower fuse tube terminal 19 which forms a discharge terminal and, because of the intensity of the blast action and the accompanying pressure, it is desirable that the flow of these arc products be substantially unimpeded in their escape downwardly through the metallic exhaust tube 81 and the fuse tube terminal 19 to the atmosphere. The exhaust tube 81 and the fuse tube terminal 19 forms a discharge passageway for the arc products. However, such operation can be eflected only by blowing of the fusible element 83 and this ordinarily takes place only when the current flow therethrough is of a predetermined magnitude exceeding its normal load current carrying capacity.

As indicated hereinbefore it is sometimes desirable to release the rod-like terminal 61 for movement upwardly through the bore 60 in order to take advantage of its arc extinguishing capability under conditions where the fusible element 83 of the dropout fuse 16 would not respond or blow or would not respond or blow with the desired speed. Accordingly, trigger means, shown generally at 89, are provided in accordance with this invention for releasing the fusible element terminal 84 in response to operation of the external trigger operating mechanism 33. As a result the rod-like terminal 61 moves upwardly and carries with it the fusible element 83 and the fusible element terminal 84. This action would normally be made to take place only when load current or fault current of low value, as in stepdown substation transformer installations under overload conditions, secondary fault conditions or internal fault conditions, is flowing through the dropout fuse 16. Internal faults may occur when the transformers are carrying little or no load. Under such conditions the current to be interrupted may be only slightly higher than normal exciting current. Such relatively low currents can be readily interrupted and the are drawn between the terminal 84 and the trigger means 89 or the fitting 80 extinguished since the bore 60 in the are extinguishing material 58 has suitable diameter and adequate length to effect these results. While there is a reduction in break distance due to the withdrawal of the complete fusible element 83 and the terminal 84, the length of the bore 60 is made sufiicient to accommodate this extension of the rod-like terminal 61.

For cooperating with the trigger means 89 the fusible element terminal 83 is provided with an annular shoulder portion 90 which has an annular latch surface 91 at its upper end that is arranged to be engaged by fusible element terminal latch means, shown generally at 92. The fusible element terminal latch means 92 is provided not only for making a mechanical connection between the fusible element terminal 84 and the lower fuse tube terminal 19 to restrain the coil compression spring 77 but also it is arranged to provide a high pressure electrical connection therebetween. In general, instead of directly interconnectig the fusible element terminal 84 to the upper end of the metallic exhaust tube 81 to provide the desired releasable mechanical and electrical connection thereto, the fusible element terminal latch means 92 at the upper end of the metallic exhaust tube 81 provides these releasable connections. As will appear hereinafter the latch means 92 extends to the lower end of the metallic exhaust tube 81 where the mechanical and electrical connections are completed to it and to the lower fuse tube terminal 19. In addition the construction of the fusible element terminal latch means 92 and parts associated therewith is such that a minimum of obstruction is offered to the flow of the arc products through the metallic exhaust tube 81. It will be recalled that this is particularly important when the fusible element 83 blows as a result of the flow therethrough of high fault current which results in the evolution of a substantial quantity of arc extinguishing material from the bore 60 and the generation of substantial pressure within the metallic exhaust tube 81 which should be promptly released to the atmosphere.

It will be observed that the fusible element terminal latch means 92 includes a pair of latch hooks 93-93 that are laterally movable and are formed of good conducting material such as copper. The latch hooks 93-93 are provided with jaw portions 94-94 the undersurfaces 94-94 of which are arranged to engage the annular latch surface 91 and restrain upward movement of the fusible element terminal 84. The jaw portions 94-94 are provided with facing cylindrical surfaces 95-95, FIG. 6, which may be V-shaped and are arranged to engage opposite sides of a shank 96 that forms an integral part of the fusible element terminal 84 and from which the annular shoulder portion 90 depends. Also, the jaw portions 94-94 have outflared surfaces 97-97 for guiding a beveled lower end 98 of the annular shoulder portion 90 between the jaw portions 94-94, which are spaced apart as described hereinafter, when the fusible element terminal 84 is drawn downwardly through the fuse tube 17 to tension the spring 77 and to place the fusible element terminal 84 in engagement wtih the fusible element terminal latch means 92.

To facilitate this latching operation the annular shoulder portion 90 is internally threaded, as indicated at 99, for removably receiving a tool which is shown by broken lines in FIG. 3C. It will understood that the tool 100 is in the form of an elongated rod which is threaded at one end for engagement wtih the threaded opening 99 in the annular shoulder portion 90 of the fusible element terminal 84. The tool 100 is long enough to extend out of the lower end of the fuse tube 17 and out of the lower end of the lower fuse tube terminal 19 while it is in engagement with the threaded opening 99 of the annular shoulder portion 90 and the fusible element terminal 84 is retracted to a position within the bore 60. On application of endwise tension to the tool 100, the fusible element terminal 84 is drawn downwardly through the bore. 60 and the spring 77 is compressed to store the energy for moving the rod-like terminal 61 upwardly when it is released. After the fusible element terminal 84 has been latched by the fusible element terminal latch means 92, the tool 100 is unscrewed and withdrawn.

As shown in FIGS. 3-C and 5 the latch hooks 93-93 are provided with flat shanks 102-102 which are secured by transversely extending rivets 103-103 to the bifurcated ends 104-104 of flexible beam members 105-105 which may be formed of good conducting material such as spring temper beryllium copper. The lower ends of the flexible beam members 105-105 are secured by press fit and by rivets 106-106 to a lower bridge 107, FIGS. 3-H. and 4, which is formed of good conducting material, such as brass, and which extends into contact engagement with and is suitably secured bybrazing or by screws to the lower end of the metallic exhaust tube 81 and to the spacing ring 82 and in contact engagement with the inner surface of the lower fuse tube terminal 19. In order to increase the flexibility of the beam members 105-105 they may be provided with reduced diameter or flattened intermediate portions as indicated at 108-108. Now it will be apparent that the fusible element terminal 84 is electrically and mechanically connected to the lower fuse tube terminal 19 through the latch hooks 93-93 carried by the flexible beam members 105-105 which are supported on the lower bridge 107 that is mechanically and electrically connected to the lower fuse 9 tube terminal 19 and parts immediately associated therewith.

With a view to holding the jaw portions 94-94 of the latch hooks 93-93 in high pressure latching engagement with the fusible element terminal 84 and to insure that the engagement here is positive and will be unaffected by vibration, lower wedging surfaces 111111 face outer sides 112-112 of slotted openings 113-113, FIG. 5, in a cam member 114, which may be formed of brass, and which is secured at 115 to the upper end of an operator 116 that is in the form of a metallic tube having a central opening 117 extending through it for receiving the tool 100 previously referred to. As shown in FIG. 3-E, the lower end of the operator 116 is slidably mounted in a central opening 118 in the lower bridge 107. A coil compression spring 119 reacts between the underside of the lower bridge 107 and a shouldered fitting 120 on the lower end of the operator 116 to bias the latter downwardly. This maintains the lower portions of the outer sides 112-112 of the slotted openings 113-113 in the cam member 114 in wedging engagement with the lower portions of the wedging surfaces 111-111 and springs the beam members 105-104 toward each other. As a result the jaw portions 94-94 are firmly held in resilient pressure engagement with opposite sides of the shank 96 of the fusible element terminal 84 and the undersurfaces 94-94 thereof are held in latching engagement with the annular latch surface 91 on the annular shoulder portion 90.

When the fusible element terminal 84 is to be latched or to be released, it is desirable that the jaw portions 94-94 be moved laterally apart simultaneously and completely out of engagement with the annular latch surface 94 to the end that there is no likelihood on release that it will be hung up on one of the jaw portions 94. In part, this is accomplished through the provision of upper wedging surfaces 123-123, FIG. 3-C, on the inner sides of the shanks 102-102 of the latch hooks 93-93. When the operator 116 is moved upwardly to permit latching of the terminal 84 or to release it, the operator 116 carries with it the cam member 114. The inner sides 124-124 of the slotted openings 113-113 engage with the upper wedging surfaces 123-123 and move the jaw portions 94-94 apart to permit entry of the shoulder portion 90 as drawn down by the tool 100 or its release as the case may be. This is permitted because the outer sides 112-112 of the slotted openings 113-113 move upwardly with respect to the lower wedging surfaces 111-111. Additional time for release of the terminal 84 from the latch hooks 93-93 can be obtained by causing the inner sides 124-124 of the openings 113-113 in the cam member 114 to engage wedgingly flat sides 126-126 of the shanks 102-102. Such action is obtainable by providing for a corresponding endwise inward movement of the operator 116 and the jaw portions 94-94 are held apart.

It is desirable that the annular shoulder portion- 90 of the terminal 84 be centered and that the jaw portions 94-94 be guided to move in a plane to the end that they engage or disengage the contact shank 96 and the annular latch surface 91 of the annular shoulder portion 90 when the fusible element 84 is to be engaged or released when the operator 116 is moved endwise to actuate the latch hooks 93-93. This is partly accomplished by guiding the jaw portions 94-94 in their lateral movement together or apart between upper bridge members 127- 127, FIGS. 3-C and 6, which are secured at their ends to the lower end of the metallic annular fitting 80 as by brazing. Intermediate the ends of the upper bridge members 127-127 transverse grooves 128-128 are formed for receiving and guiding the annular shoulder portion 90. Because of corrosion or for other reasons after the dropout fuse 16 has been in service a long period, there may be the tendency for the annular latch surface 91 to become attached to the undersurfaces 94'-94' of the 10 jaw portions 94-94. When the jaw portions 94-94 are moved apart, unless they completely disengage the opposite sides of the annular latch surface 91, it might be possible that the annular shoulder portion 90 would hang up on one of the jaw portions 94. This is prevented since the transverse grooves 128-128 in the upper bridge members 127-127 hold the annular shoulder portion 90 in centered relation with respect to the oppositely moving jaw portions 94-94. Since their movement apart is insured by the engagement of the upper wedging surfaces 123-123 with the inner sides 124-124 of the slotted openings 113-113, the fusible element terminal 84 always is positively released as a result of the upward movement of the operator 116.

Referring now particularly to FIG. 3-D, it will be observed that this shows the construction illustrated in FIG. 3-0 but with the operator 116 and cam member 114 thereon moved upwardly to disengage the lower wedging surfaces 111-111 and engage the upper wedging sur faces 123-123 to move the jaw portions 94-94 apart and out of engagement with the annular latch surface 91. As a result the fusible element terminal 94 is released to move upwardly, as indicated by the arrow 129, under the influence of the coil compression spring 77. During the releasing movement of the fusible element terminal 84, the annular shoulder portion thereof is centered by the transverse grooves, one being shown at 128 in FIG. 3-D, while the jaw portions 94-94 are moved apart in One plane as guided by the upper bridge members 127- 127. As a result of the release of the fusible element terminal 84, in the manner described, it moves upwardly under the influence of the coil compression spring 77 in the direction indicated by the arrow 129, FIG. 3-D, and, if current is flowing in the circuit in which the dropout fuse 16 is connected, an arc is drawn between the lower end of the annular shoulder portion 90 and one or the other or both of the jaw portions 94-94. The are is extended into the bore 60 and extinguished as the rod-like terminal 61 moves upwardly therethrough together with the fusible element 83 and fusible element terminal 84. The flow of the deionizing vapor and the resulting are products downwardly through the metallic exhaust tube 81 is substantially unimpeded because of the relatively small obstruction provided therein by the latch hooks 93-93, the flexible beam members -105, the upper bridge members 127-127, the cam member 114, the lower bridge 107 and the operator 116. Examination of FIGS. 4, 5 and 6 shows that there is a substantial area on opposite sides of the trigger means 89 extending into the lower end of the metallic exhaust tube 81 to permit the relatively free and unimpeded flow of are products through these passageways on opposite sides and to the atmosphere through the lower end of the lower fuse tube terminal 19. This is particularly important when high fault currents are to be interrupted and the fusible element blows to initiate the drawing of an are.

As a further result of the release of the fusible element terminal 84 by separation of the jaw portions 94-94, the coil compression spring 77 moves the compression tube 75 upwardly sufficiently far to cause the tube end fitting 74 to engage the underside of the upper end 25 of the unlatching tube 25. The unlatching tube 25 moves upwardly carrying with it the flange 24 to lift the latch arm 20 and permit the dropout fuse 16 to rotate about the pivot 21 on the lower line terminal 15 downwardly to open position where it engages the resilient bumper 30 and its movement in the full open position is arrested thereby.

It is desirable that the lower end of the lower fuse tube terminal 19 be closed off in order to prevent the entrance of extraneous material such as insects and the like into the interior of the dropout fuse 16. For this purpose, as shown in FIG. 3-E, a frangible or flexible closure disc 13.0 is employed. It is located in an annular groove 131 near the lower end of the lower fuse tube terminal 19 and extends underneath the lower end of the fitting 120. A snap ring 132, also located in the groove 131, serves to hold the frangible closure disc 136 in place. When the dropout fuse 16 is operated in a manner such as to cause the flow of arc products downwardly through the metallic exhaust tube 81 and through the lower fuse tube terminal 19, the frangible or flexible closure disc 130 is readily ruptured or blown out to permit their escape to the atmosphere. Also it can be broken or sprung readily, as described hereinafter, by an external blow applied to move the operator 116 upwardly for triggering the dropout fuse 16.

As pointed out hereinbefore, the particular external trig- :ger operating mechanism 33 is the invention of William A. Gussow and is claimed in Patent No. 3,184,567, issued May 18, 1965. However, it will be understood that any other external trigger operating mechanism can be employed which is capable of moving the operator 116 endwise with suffiicent force to trip the trigger means 89 and release the fusible element terminal 84. Preferably this is accomplished with a snap action by sharply impacting the lower end of the operator 116.

The details of construction of the external trigger operating mechanism 33 are shown in FIGS. 7, 8 and 9 of the drawings to which reference now will be had. Here it will be observed that the trip arm 37 is rotatably mounted on a reduced diameter outer end portion 135 of a stud 136 that extends through the support bracket 34 and is secured thereon by nuts 137 which are threaded on a threaded portion of the stud 136 as shown in FIG. 8. It will be understood that the trip arm 37 rotates about the longitudinal axis of the stud 136, the axis being indicated. at 138 in FIGS. 7 and 9. The axis 138 extends in spaced relation to the longitudinal axis of the fuse tube 17 and transversely thereof when it is in the closed position shown, for example, in FIG. 2. The trip arm 37 is biased to its non-operated or retrieved position, shown in FIG. 7, by a helical spring 139 which surrounds the stud 136 having one end 140 anchored to the support bracket 34 and its other end 141 anchored. to a hub portion 142 of the trip arm 37. It will be noted in FIG. 9 that the trip arm 37 has a curved outer end portion the distal end 144 of which is arranged to impact through the frangible closure disc 132 the lower side of the shouldered fitting 120 on the lower end of the operator 116 for the purpose of moving it upwardly to effect the release of the trigger means 89 in the manner previously described. The closure disc 132 is ruptured by this action.

It is important that the terminal positions of the trip arm 37 be accurately controlled and be adjustable in order to compensate for possible dislocation of parts of the trigger operating mechanism 33 in relation to each other and due to varying deflections of the

insulators

13 and 39. For this purpose an adjustable stop screw 145 is threaded through the sleet hood 35, as shown in FIGS. 7 and 9, and it is locked in place by a lock nut 146. The distal end of the adjustable stop screw 145 controls the position to which the trip arm 37 is retrieved or its nonoperated position as shown in FIG. 7. Another adjustable stop screw 147 is provided. It is threaded through one leg of a transverse angle member 148 that is secured, as by welding, to the underside of the sleet hood 35. A lock nut 149 serves to hold the stop screw 147 in adjusted position. As shown in FIG. 9, when a shoulder 37' on the trip arm 37 engages the head 147' of the adjustable stop screw 147, further forward movement of the trip arm 37 is prevented. The adjustment of the stop screw 147 is such that the distal end 144 of the trip arm 37 is caused to move the operator 116 upwardly in a positive manner through a distance sufficient to move the cam member 114 to the unlatching position shown in FIG. 3-D of the drawings in order to unlatch positively the trigger means 89 and release the fusible element terminal 84. The adjustment of the stop screw 147 can be such 12 as to permit movement of the operator 116 far enough to cause the inner sides 124-124 of the openings 113113 in the cam member 114 to engage wedgingly the fiat surfaces 126-126 as previously described.

It will be observed that the end of the helical spring 139, which biases the trip arm 37 to the nonoperated position, extends underneath the transverse angle member 148, FIGS. 7 and 9, and thereby is held against movement with respect to the support bracket 34.

It will be recalled that, when the fusible element terminal 84 is released as a result of the impact being applied to the lower end of the operator 116, the fuse tube 17 is unlatched from the upper line terminal 14 and swings downwardly to the open position. It is desirable that the trip arm 37 be returned to the non-operated position promptly by the spring 139 or at least moved to a position Where the curved outer end portion 143 thereof is out of the path of downward swinging movement of the dropout fuse 16 so as not to interfere with such action. For this purpose a trip free connection, shown generally at 150, is provided for mechanically interconnecting the trip arm 37 to the actuating lever 38 with the arrangement being such that, after the trip arm 37 has completed its function of moving the operator 116 upwardly to trigger the trigger means 89, the operating connection is no longer maintained and the trip arm 37 is free to be returned. to the non-operated position without regard to the position of the actuating lever 38 which may be returned to the non-operated position at a later time and at a relatively slow speed.

The trip free connection includes a trip free arm 151 having one bifurcated. end pivotally secured at 152 to a hub 37 that forms an integral part of the trip arm 37. As seen in FIGS. 7 and 9, the axis 153 of the pivot 152 about which the trip free arm 151 rotates is parallel to the axis 138 about which the trip arm 37 rotates on the stud 136. It will be noted that the trip free arm 151 has a shoulder 154 that is arranged to engage a juxtaposed portion of the trip arm 37 for the purpose of causing conjoint movement thereof when a force is applied to the trip free arm 151 by the actuating lever 38. The other end 155 of the trip free arm 151 is bifurcated and a roller 156 is located between the arms thereof on a pin 157 which extends therethrough and has an extension 158 to which one end of a spring 159 is secured. The spring 159 is a coil tension spring and its other end is connected at 160 to the trip arm 37.

The actuating lever 38 includes an upstanding arm portion 163 that is formed integrally with a base 164 which is secured by bolts 165 to the distal end of the rotatable insulator 39. The distal end 166 of the upstanding arm portion 163 is rounded and is arranged to engage the roller 156 when the insulator 39 is rotated to rotate the actuating lever 38. It will be observed that the axis of rotation of the rotatable insulator 39 is indicated at 167 and that this axis is parallel to the axis 138 of rotation of the trip arm 37.

When the rotatable insulator 39 is rotated about its axis 167 in a counterclockwise direction as indicated by the arrow 168 in FIG. 7 and the arrow 169 in FIG. 9, the trip arm 37 is rotated in a clockwise direction from its position shown in FIG. 7 to the position shown in FIG. 9 and. in the direction indicated by the arrow 170. The arrangement is such that the rounded distal end 166 of the actuating lever 38 engages the roller 156 and maintains mechanical engagement therewith until the trip arm 37 has rotated sufficiently far to cause the distal end 144 thereof to impact the underside of the disc 130 and thereby the fitting 120 on the lower end of the operator 116 to move it positively upwardly a distance sufficient to trigger the trigger means 89 and positively release the fusible element terminal 84. Continued rotation of the actuating lever 38 in the direction indicated by the arrow 169 causes its rounded end 166 to move past the roller 156 and out of its path of movement. When this takes place, which is a result of the provision of the trip free connection 150, the trip arm 37 is no longer driven in the direction indicated by the arrow 170 and, since the helical spring 139 has been additionally tensioned by the previous rotation of the trip arm 37 to the operated position, the spring 139 is not restrained and it biases the trip arm 37 to the non-operated or retrieved position shown in FIG. 7.

When the actuating lever 38 subsequently is returned to its non-operated position by rotation of its insulator 39 in a clockwise direction, the rounded end 166 engages the roller 156. However, since the trip arm 37 is prevented from any further rotation in a counterclockwise direction by the adjustable stop screw 145, the engagement of the roller 156 by the rounded end 166 swings the trip free arm 151 about its pivot 152 and tenisons the spring 159. Then, after the rounded end 166 has moved to the position shown in FIG. 7 and out of mechanical engagement with the roller 156, the spring 159 retrieves the trip free arm 151 and rotates it in a clockwise direction until its shoulder 154 engages the trip arm 37 in the position shown in FIG. 7.

FIGS. 10, 11 and 12 show generally at 89 a modified construction for trigger means which can be employed in lieu of the trigger means 89 previously described and shown in FIGS. 3-C and 3-D. Where the same elements are employed in the modified construction as previously described, the same reference characters are used in FIGS. 10, 11 and 12.

In this embodiment of the invention it is unnecessary to employ the upper bridge members 127--127 for centeringa fusible element terminal 173 which corresponds to the fusible element terminal 84 previously described. The fusible element terminal 173 includes an upper section 174'for receiving the lower end of the fusible element 83, or more particularly the lower end of the fuse wire 85 and the strain wire 86. The section 174 is connected by a reduced diameter shank 175 to an annular shoulder portion 176 which corresponds to the annular shoulder portion 90 of the fusible element terminal 84. The annularshoulder portion 176 is provided with an upwardly facing annular latch surface 177 which is arranged to have latching engagement with the downwardly facing surfaces 94-94' of the jaw portions 9494 that, as previously described, constitute portions of the latch hooks 9393. For triggering the trigger means 89' an operator 116' is provided which is generally the same in construction as the operator 116, previously described, and it carries the cam member 114 near its upper end. The operator 116' has the central opening 117 therethrough for receiving the tool 100. At its upper end the operator 116' is provided with a bifurcated extension 178 forming slots 179- 179, FIG. 11, through which the juxtaposed portions of the jaws 9494 extend and in which they are loosely guided for their lateral movement apart. In addition, the tubular bifurcated extension 178 functions to center and guide the annular shoulder portion 176 therethrough and to hold it centrally with respect to the jaw portions 9494 to the end that the annular latch surface 177 does not hang up on the underside 94' of one of them when the trigger means 89 is triggered by the upward movement of the operator 116 in the manner described for the operator 116.

The annular shoulder portion 176 is provided with a beveled lower end180 and with a threaded opening 181 for receiving the removable tool 100 through the central opening 117 in the operator 116'. It will be understood that, when the operator 116 is moved inwardly, as shown in FIG. 12, to spread the jaw portions 9494 apart and the tool 100' is threaded into the openings 181 and a downward tenison force is applied thereto, the annular shoulder portion 176 is moved downwardly. The beveled lower end 180 is guided by the tubular bifurcated extension 178 of the operator 116. The downward movement of the annular shoulder portion176 continues inside the extension 178 until the annular latch surface 177 clears the undersurfaces 94'94' of the jaw portions 94- 94. Then a downward movement of the operator 116 moves the cam member 114 to the position shown in FIG. 10 where the semi-cylindrical surfaces 95-95 move into positive contact engagement with diametrically opposite surfaces of the shank and the undersurfaces 94-94 are in latchingengagement with the latch surface 177.

In FIG. 10 it will be noted that the slots 179-179 extend a substantial distance below the annular shoulder portion 176 of the fusible element terminal 173. The reason for this, as shown in FIG. 12, is to permit substantial upward movement of the operator 116' with respect to the jaw portions 9494 incident to upward movement of the cam member 114 and movement apart of the jaw portions 94-94. These jaw portions 94--94 are guided in their lateral outward movements in the slots 179-179 and also the annular shoulder portion 176 of the fusible element terminal 173 is restrained laterally by extension 178, while the jaw portions 9494 are moved apart, and is guided laterally in its upward movement as the fusible element terminal 173 moves upwardly in the direction indicated by the arrow 182.

In the construction shown in FIGS. 10 and 12 the latch hooks 9393 and the terminal 173 are guided and controlled by the tubular operator 116' and the cam member 114 rigidly joined thereto. It will be apparent that the trigger means 89' can be assembled and inspected as a unitary sub-assembly. The alignment and functioning of the various parts can be checked. The unitary sub-assembly can then be inserted into the metallic exhaust tube 81 and held in place by a threaded or knurled connection without any limitation as to rotational alignment since the terminal 173 is a rotational body concentric about its longitudinal axis and in line with the guiding, latching and contact means of the unitary sub-assembly. There is no likelihood that uncontrolled friction forces will be set up that would interfere with the movement of latch hooks 9393 in either embodiment. This construction facilitates placing the releasable contact assembly at the inner end of the metallic exhaust tube 81 where, after assembly therein, it cannot be inspected for alignment and operation.

The positioning of the trigger means 89 or 89', FIGS. 3-C-3-D-10 and 12, wholly within the metallic exhaust tube 81 which is surrounded by the fuse tube 17 of dielectric material and positioning of the releasable contacts at the inner end of this tube 81 in contradistinction to having a part extend radially through the

tubes

17 and 81 can be accomplished to utilize the greater longitudinal space within the metallic tube 81 to provide a non-critical mechanism without upsetting in any way the dielectric field extending from the tube 81 which also functions as an electrostatic stress distribution cone or the exterior insulation value of the fuse tube assembly and without unduly obstructing the fuse exhaust.

While only two latch hooks 9393 with a corresponding number of jaw portions 9494 are shown, it is possible to use either a single movable latch book 93 and jaw portion 94 with a stationary latch hook and jaw portion or to use more than two movable latch hooks 93 and jaw portions 94 or additional jaw portions without hooks depending upon the magnitude of the current flow and the necessary operating conditions.

The function of the fusible element 83 is to effect the operation of the dropout fuse 16 under predetermined current conditions. Where such operation is not required and only the triggered action is used, the fusible element 83 can be omitted and the terminal 84 or 173 made an integral part of or an extension of the rod-like terminal 61. In either case the triggering functioning in response to an operation wholly external to the dropout fuse 16 would be as described herein.

The dropout action of the fuse 16 is employed to provide an air gap in the circuit between the

line terminals

14 and 15. Where this function is not required, the triggering action herein described can be employed solely to interrupt the circuit within the fuse tube 17 of the nondropout type and without the accompanying dropout action.

In some instances it is desirable to provide for individual operation of the dropout fuse construction rather than for their group operation by the operator 54 as described herein. For example, if one of the devices operates as a result of blowing of its fusible element 83, the other two devices in a three phase installation should be operated to avoid single phase operation. By providing means responsive to the operation of one dropout fuse construction 10 to release operators 54 individual to the other two devices, they can be operated to completely isolate the three phase circuit normally energized therethrough.

It will be recalled that the terminal 84 or 173 is securely gripped by the trigger means 89 or 89. When the fusible element blows and there is any downward movement of the terminal 84 or 173, such movement is limited by engagement with the upper end 183 of the operator 116, FIG. 3C, or with an internal shoulder 184 of the operator 116, FIG. 10. Thus there is no likelihood that the terminal 84 or 173 will be expelled from the lower end of the fuse tube 17.

What is claimed as new is:

1. A circuit interrupter construction for use on electric power transmission circuits operating at voltages of the order of several thousand volts comprising, in combination:

(a) line terminals in insulated spaced relation,

(b) a tubular insulating housing having terminals at its ends in contact engagement with said line terminals,

(c) a metallic tube extending into said housing from each end terminal,

((1) means in said housing between said metallic tubes providing a bore from which an arc extinguishing medium is evolved due to the heat of an are,

(e) are drawing terminal means movable in said bore and connected to one end terminal of said housing through the metallic tube connected thereto,

(f) means biasing said are drawing terminal means for movement in said bore toward said one end terminal,

(g) the metallic tube extending from the other end terminal providing an arc product discharge passageway from said bore,

(11) latch means in said discharge passageway, mounted on said other end terminal, providing an electric connection between it and said arc drawing terminal means, and restraining said biasing means, and

(i) trigger means extending endwise into said arc product discharge passageway and operable axially of said other end terminal for releasing said latch means.

2. A circuit interrupter construction for use on electric power transmission circuits operating at voltages of the order of several thousand volts comprising, in combination:

(a) upper and lower line terminals in insulated spaced relation,

(b) latch means on said upper line terminal,

(c) a dropout tubular insulating housing having upper and lower housing terminals with its lower terminal providing a discharge passageway for are products and pivotally mounted on said lower line terminal and its upper terminal latched by said latch means to said upper line terminal,

((1) spring operated latch release means in said housing arranged and adapted when released to trip said latch means whereby said housing is permitted to swing downwardly to open position,

(e) upper and lower metallic tubes extending into said housing from each housing terminal with said lower metallic tube forming a part of said discharge passageway,

(f) means in said housing between said metallic tubes providing a bore from which an arc extinguishing medium is evolved due to the heat of an arc,

(g) are drawing terminal means biased for movement in said bore by said spring operated latch release means toward said upper housing terminal and connected thereto through said upper metallic tube,

(h) are drawing terminal latch means in said discharge passageway, mounted on said lower housing terminal, releasably connected to said are drawing terminal means and restraining said spring operated latch means, and

(i) trigger means extending endwise into said lower metallic tube and operable axially of said lower housing terminal for releasing said are drawing terminal latch means to release said arc drawing terminal for movement through said bore followed by tripping of said latch means on said upper line terminal.

3. A triggered fuse construction for use on electric power transmission circuits operating at voltages of the order of several thousand volts comprising, in combination:

(a) upper and lower line terminals in insulated spaced relation,

(b) a fuse tube having upper and lower fuse tube terminals at its ends in engagement with said upper and lower line terminals,

(c) a metallic tube extending into said housing from each fuse tube terminal,

(d) means in said fuse tube between said metallic tubes providing a bore from which an arc extinguishing medium is evolved due to the heat of an arc,

(e) an are drawing rod-like terminal movable in said bore and connected at its upper end to said upper fuse tube terminal through the metallic tube individual thereto,

(f) means biasing said rod-like terminal for upward movement in said bore,

(g) a fusible element connected at its upper end to the lower end of said rod-like terminal,

(h) an arc drawing fusible element terminal connected to the lower end of said fusible element and movable upwardly in said bore,

(i) the metallic tube extending from said lower fuse tube terminal providing an are product discharge passageway from said bore,

(j) latch means in said discharge passageway, mounted on said lower fuse tube terminal, providing an electrical connection between it and said are drawing fusible element terminal, and restraining said biasing means, and

(k) trigger means extending endwise into said are product discharge passageway and operable axially of said lower fuse tube terminal for releasing said are drawing fusible element terminal.

4. A triggered fuse construction for use on electric power transmission circuits operating at voltages of the order of several thousand volts comprising, in combination:

(a) upper and lower line terminals in insulated spaced relation,

(b) fuse tube latch means on said upper line terminal,

(c) a dropout fuse tube having upper and lower fuse tube terminals with its lower fuse tube terminal providing a discharge passageway for are products and pivotally mounted on said lower line terminal and its upper fuse tube terminal latched by said fuse tube latch means to said upper line terminal,

(d) spring operated fuse tube latch release means in said dropout fuse tube arranged and adapted when released to trip said fuse tube latch means whereby said fuse tube is permitted to swing downwardly to open position,

(e) upper and lower metallic tubes extending into said ,15 tube from each fuse tube terminal with said lower metallic tube forming a part of said discharge passageway,

(f) means in said fuse tube between said metallic tubes providing a bore from which an arc extinguishing medium is evolved due to the heat of an arc,

(g) an are drawing rod-like terminal movable in said bore, connected at its upper end to said upper fuse tube terminal through the metallic tube individual thereto, and biased for upward movement in said bore by said spring operated fuse tube latch release means,

(h) a fusible element connected at its upper end to the lower end of said rod-like terminal,

(i) an are drawing fusible element terminal connected to the lower end of said fusible element and movable upwardly in said bore,

(j) latch means in said discharge passageway, mounted on said lower fuse tube terminal, providing an electrical connection between it and said are drawing fusible element terminal, and restraining said spring operated fuse tube latch release means, and

5. A triggered fuse construction for use on electric power transmission circuits operating at voltages of the order of several thousand volts comprising, in combination:

(a) upper and lower line terminals in insulated spaced relation,

(b) fuse tube latch means on said upper line terminal,

() a dropout fuse tube having upper and lower fuse tube terminals with its lower fuse tube terminal providing a discharge passageway for arc products and pivotally mounted on said lower line terminal and its upper fuse tube terminal latched by said fuse tube latch means, to said upper line terminal,

(e) an are drawing rod-like terminal biased for upward movement in said fuse tube by said spring operated latch release means,

(f) a fusible element in said dropout fuse tube adjacent said lower fuse tube terminal and connected at its upper end to the lower end of said are drawing rod-like terminal the upper end of which is connected to said upper fuse tube terminal, said fusible element restraining said are drawing rod-like terminal and arranged and adapted to initiate the operation of said fuse tube latch release means on flow of predetermined current through said fusible element,

(g) an are drawing fusible element terminal connected to the lower end of said fusible element,

(h) fusible element terminal latch means on said lower fuse tube terminal providing a connection between said arc drawing fusible element and said lower fuse tube terminal and restraining said are drawing rodlike terminal through said fusible element,

(i) means in said fuse tube providing a bore through which said rod-like terminal is drawn on blowing of said fusible element and through which said rodlike terminal, fusible element and are drawing terminal are drawn on release of said fusible element terminal latch means and from which bore an arc extinguishing medium is evolved due to the heat of the arc, and

(j) trigger means extending into said discharge passageway and operable through said lower fuse tube terminal for releasing said fusible element terminal latch means, said trigger means including an operator movable endwise of said lower fuse tube terminal for striking said latch means to effect release of said are drawing terminal for movement through said bore.

6. The invention, as set forth in claim 5, wherein:

(a) the are drawing fusible element terminal has tool receiving means, and

(b) the operator is tubular to permit application of a tool therethrough to engage said tool receiving means and draw said fusible element terminal into engagement with the fusible element terminal latch means.

7. The invention, as set forth in claim 5, wherein impact producing means are provided for momentarily striking and driving the operator endwise to strike the fusible element terminal latch means and release the are drawing terminal whereupon the spring operated fuse tube latch release means is operated to unlatch the fuse tube latch means and permit the fuse tube to swing to open position.

8. The invention, as set forth in claim 7, wherein:

(a) a plurality of triggered fuse constructions are provided, and

(b) impact producing means are provided for simultaneously momentarily striking and driving the respective operator endwise to effect simultaneous circuit interruption by each fuse construction followed by swinging thereof to open position.

9. The invention, as set forth in claim 5, wherein:

(a) the are drawing fusible element terminal has a latching shoulder,

(b) the fusible element terminal latch means includes a laterally movable latch hook for latching engagement with said latching shoulder, and

(c) the operator is biased for endwise movement in one direction into engagement with said latch hook to hold it in latching engagement with said latching shoulder and on endwise movement in the opposite direction is arranged and adapted to strike and move said latch hook out of latching engagement with said latching shoulder.

10. The invention, as set forth in claim 9, wherein the latch hook is mounted on the distal end of a flexible conducting bea-m member rigidly secured at the other end to the lower fuse tube terminal and providing an electrical and mechanical connection thereto.

11. The invention, as set forth in Claim 10, wherein:

(a) mechanical advantage means on the operator and on the latch hook cooperate to positively hold said latch hook in latching engagement with the latching shoulder on the fusible element terminal and against vibration and in contact engagement under pressure with said fusible element terminal, and

(b) additional mechanical advantage means on said operator and on said latch hook cooperate to move said latch hook out of latching engagement with said latching shoulder as a result of endwise movement of said operator to release said fusible element terminal to draw and extinguish an arc in the fuse tube and to release the spring operated fuse tube latch release means.

12. The invention, as set forth in Claim 5, wherein:

(a) the fusible element terminal has an annular latching shoulder,

(b) the fusible element terminal latch means includes a pair of latch hooks laterally movable away from said fusible element terminal and engaging said annular latching shoulder at diametrically opposite sides, and

(-c) the operator is a rod-like member, is biased for endwise movement in one direction into engagement at one end with said latch hooks, is slidably mounted at its other end on the lower fuse tube terminal, and on endwise movement in the opposite direction is arranged and adapted to displace said latch hooks out of latching engagement with said annular latching shoulder.

13. The invention, as set forth in claim 12, wherein the latch hooks are mounted on the distal ends of flexible conducting beam member rigidly secured at their other ends to the lower fuse tube terminal and providing an electrical and mechanical connection thereto.

14. The invention, as set forth in claim 13, wherein:

(a) wedge means on the one end of the operator and on the latch hooks cooperate to positively hold said latch hooks against movement apart and in latching engagement with the annular latching shoulder on the fusible element terminal and against vibration, and

(b) additional wedge means on said one end of said operator and on said latch hooks cooperate to move them apart and out of latching engagement with said latching shoulder as a result of endwise movement of said operator to release said fusible element terminal.

15. The invention, as set forth in claim 14, wherein a guide means is mounted in the discharge passageway provided by the lower fuse tube terminal and cooperates with the latch hooks for guiding them in their lateral movement apart and presents a relatively small obstruction to the discharge of are products through said lower fuse tube terminal.

16. The invention, as set forth in claim 15, wherein the guide means. includes a guide bridge transversely grooved on opposite sides of the annular latching shoulder of the fusible element terminal to prevent lateral movement thereon on disengaging movement of the latch hooks from said annular latching shoulder to insure that both latch hooks are disengaged therefrom.

17. The invention, as set forth in claim 14, wherein a support bridge extends transversely of the lower fuse tube terminal for mounting the other ends of the flexible conducting beam members and presents a relatively small obstruction to the discharge of arc products through said lower fuse tube terminal.

18. The invention, as set forth in claim 12, wherein the one end of the operator is tubular, is telescoped over the annular latching shoulder of the fusible element terminal, is longitudinally slotted to receive the latch hooks, and functions to prevent relative lateral movement of said annular latching shoulder on disengaging movement of said latch hooks therefrom to insure that both latch hooks are disengaged therefrom.

19. In a fuse construction, in combination:

(a) a fuse tube,

(b) an external terminal at one end of said fuse tube,

(c) a metallic tube extending into said fuse tube at said one end from said external terminal and providing an are product discharge passageway,

(d) an are drawing terminal means in said fuse tube and biased for movement away from said metallic tube,

(e) latch means in said discharge passageway, mounted on said external terminal, providing an electrical connection between it and said are drawing terminal means, and restraining it against said movement, and

(f) trigger means extending endwise into said are product discharge passageway and operable axially of said external terminal for releasing said latch means.

20. The invention, as set forth in claim 19, wherein the trigger means includes an operator movable endwise of the metallic tube and of the external terminal for striking the latch means to release the are drawing terminal means.

21. The invention, as set forth in claim 4, wherein means external to the dropout fuse tube are provided for operating the trigger means.

2-2. The invention, as set forth in claim 1, wherein means external to the tubular insulating housing are provided for operating the trigger means.

23. A circuit interrupter construction for use on electric power transmission circuits operating at voltages of the order of several thousand volts comprising, in combination:

(a) line terminals in insulated spaced relation,

(c) means in said housing providing a bore from which. an arc extinguishing medium is evolved due to theheat of an are,

(d) an are drawing terminal having an annular latching shoulder movable in said bore and connected to one terminal of said housing,

(e) means biasing said are drawing terminal toward said one terminal,

(f) means in said housing providing an are product discharge passageway from said bore through said other terminal of said housing,

(g) a pair of latch hooks in said discharge passageway laterally movable away from said are drawing terminal, engaging said annular latching shoulder at diametrically opposite sides, mounted on said other terminal of said housing, providing an electrical connection between it and said arc drawing terminal, and restraining said biasing means, and

(h) a tubular operator extending into said discharge passageway, operable through said lower fuse tube terminal, telescoped over said annular latching shoulder of said are drawing terminal, longitudinally slotted to receive said latch hooks, and arranged and adapted to prevent relative lateral movement of said annular latching shoulder in disengaging movement of said latch hooks to insure that both latch hooks are disengaged therefrom.

24. In a fuse construction, in combination:

(a) a fuse tu-be,

('b) a terminal at one end of said fuse tube,

(c) means at said one end of said fuse tube providing an arc product discharge passageway through said terminal,

(d) fusible element terminal latc-h means in said discharge passageway mounted on said terminal, and (e) trigger means extending into said discharge passageway and operable through said fuse tube terminal for releasing said fusible element terminal latch means, said trigger means including an operator movable endwise of said terminal for striking said latch means to release the same.

25. In a fuse construction, in combination:

(a) a fuse tube,

(b) a terminal at one end of said fuse tube,

(c) means at said one end of said fuse tu-be providing an are product discharge passageway endwise of saidi terminal,

(d) a fusible element terminal in said fuse tube biased; for movement toward the other end of said fuse tube,.

(e) fusible element terminal latch and contact means: in said discharge passageway, mounted on said fuse tube terminal, providing an electrical connection between it and said fusible element terminal and re-- straining the latter against said movement, and

(f) trigger means extending into said discharge passageway and operable through said fuse tube terminal for releasing said fusible element terminal latch means, said trigger means including an operator movable endwise of said terminal for striking said fusible element latch and contact means to release said fusible element terminal for said movement.

26. The invention, as set forth in claim 25, wherein the trigger means includes means for positively moving the same into good contact engagement with the fusible element terminal and for completely releasing said trigger means from such contact engagement.

27. A circuit interrupter construction for use on an electric power transmission circuit operating at a voltage 21 of the order of several thousand volts comprising, in combination:

(a) a tubular insulating housing having terminals at its ends for connection to said circuit,

(b) means in said housing providing a bore from which an arc extinguishing medium is evolved due to the heat of an arc,

(c) are drawing terminal means movable in said bore, connected at one end to one of said end terminals, and having a latching shoulder adjacent its other are drawing end extending substantially at right angles to its path of movement,

(d) means biasing said are drawing terminal means for movement in said bore toward said one end terminal,

(e) resilient contact means mounted on and extending longitudinally inwardly of said other end terminal for contact engagement with said arc drawing terminal means, and having hook means engaging said latching shoulder and restraining movement of said are drawing terminal means, and

(f) means within said other end terminal for moving said hook means laterally out of engagement with said latching shoulder and said contact means laterally away from said are drawing terminal means to free the same completely for movement through said bore under the influence of said biasing means.

28. A circuit interrupter construction for use on an electric power transmission circuit operating at a Voltage of the order of several thousand volts comprising, in combination:

(e) resilient contact means mounted on and extending longitudinally inwardly of said other end terminal for contact engagement with said are drawing terminal means, and having hook means engaging said latching shoulder and restraining movement of said are drawing terminal means, and

(f) means within said other end terminal for moving said contact means into engagement with said are drawing terminal means and said hook means into latching engagement with said latching shoulder and for moving said hook means laterally out of engagement with said latching shoulder and said contact means laterally away from said are drawing terminal means to free the same completely for movement through said bore under the influence of said biasing means.

29. A circuit interrupter construction for use on an electric power transmission circuit operating at a voltage of the order of several thousand volts comprising, in combination:

(b) means in said housing providing a bore from which an arc extinguishing medium is evolved due to the heat of an are,

(c) are drawing terminal means movable in said bore, connected at one end to one of said end terminals, and having a latching shoulder adjacent its other arc drawing end extending substantially at right angles to its path of movement,

(e) a plurality of elongated flexible contact members mounted on and extending longitudinally inwardly of said other end terminal for contact engagement from opposite sides with said arc drawing terminal means, and having hook means engaging said latching shoulder and restraining movement of said are drawing terminal means, and

(f) means within said other end terminal for moving said hook means apart laterially out of engagement with said latching shoulder and said contact members apart laterally away from said are drawing terminal means to free the same completely for movement through said bore under the influence of said biasing means.

30. A circuit interrupter construction for use on an electric power transmission circuit operating at a voltage of the order of several thousand volts comprising, in combination:

(c) arc drawing terminal means movable in said bore, connected at one end to one of said end terminals, and having a latching shoulder adjacent its other are drawing end extending substantially at right angles to its path of movement,

((1) means biasing said are drawing terminal means for movement in said bore toward said one end terminal,

(e) a plurality of elongated flexible contact members mounted on and extending longitudinally inwardly of said other end terminal for contact engagement from opposite sides with said are drawing terminal means, and having hook means engaging said latching shoulder and restraining movement of said arc drawing terminal means, and

(f) means within said other end terminal for moving said contact members toward each other into engagement with said arc drawing terminal means and said hook means toward each other into latching engagement with said latching shoulder and for moving said hook means apart laterally out of engagement with said latching shoulder and said contact members apart laterally away from said are drawing terminal means to free the same completely for movement through said bore under the influence of said biasing means.

References Cited by the Examiner UNITED STATES PATENTS 2,087,744 6/1937 Triplett 200114 X 2,109,090 2/1938 Pittman et a1. 200114 2,272,717 2/ 1942 Ludwig et a1 20078 X 2,677,738 5/1954 Schneider 2001 14 2,798,133 7/1957 Curtis 200127 ROBERT K. SCHAEFER, Acting Primary Examiner. BERNARD A. GILHEANY, Examiner.

Claims

27. A CIRCUIT INTERRUPTER CONSTRUCTION FOR USE ON AN ELECTRIC POWER TRANSMISSION CIRCUIT OPERATING AT A VOLTAGE OF THE ORDER OF SEVERAL THOUSAND VOLTS COMPRISING, IN COMBINATION: (A) A TUBULAR INSULATING HOUSING HAVING TERMINALS AT ITS ENDS FOR CONNECTION TO SAID CIRCUIT, (B) MEANS IN SAID HOUSING PROVIDING A BORE FROM WHICH AN ARC EXTINGUISHING MEDIUM IS EVOLVED DUE TO THE HEAT OF AN ARC, (C) ARC DRAWING TERMINAL MEANS MOVABLE IN SAID BORE, CONNECTED AT ONE END TO ONE OF SAID END TERMINALS, AND HAVING A LATCHING SHOULDER ADJACENT ITS OTHER ARC DRAWING END EXTENDING SUBSTANTIALLY AT RIGHT ANGLES TO ITS PATH OF MOVEMENT, (D) MEANS BIASING SAID ARC DRAWING TERMINAL MEANS FOR MOVEMENT IN SAID BORE TOWARD SAID ONE END TERMINAL, (E) RESILIENT CONTACT MEANS MOUNTED ON AND EXTENDING LONGITUDINALLY INWARDLY OF SAID OTHER END TERMINAL FOR CONTACT ENGAGEMENT WITH SAID ARC DRAWING TERMINAL MEANS, AND HAVING HOOK MEANS ENGAGING SAID