US2685013A - Circuit interrupting device - Google Patents

Description

July 27, 1954 R. W. STROBEL CIRCUIT INTERRUPTING DEVICE Filed July 7, 1953 y In vento@ Rucicnlph W. Strobel,

by Wn W His ,Attomweg Patented July 27, 1954 CIRCUIT INTERRUPTING DEVICE Rudolph W. Strobel, Lenox, Mass., assigner to General Electric New York Company, a corporation of Application July 7, 1953, Serial No. 366,570

24 Claims. l

This invention relates to circuit interrupting devices and, more particularly, to circuit interrupting devices or open type cutouts employing hollow insulators.

In some prior open type cutouts employing hollow insulators the insulator has been supported from the cross arm of a pole line or the like by a metallic strap surrounding the central portion of the insulator. One disadvantage of a metallic strap is that a flashover or short circuit betwee the metallic strap and other` cutout hardware is liable to occur. To offset this danger of a ashover or short circuit the useholder tube has been supported on long arms attached to the hollow insulator in order to locate it at a suitable distance away from the metallic strap. However, when the cutout functions to clear fault currents very high recoil forces tend to move the fuseholder away from its open end towards its closed end. These high forces are multiplied by the length of said long arms and thus an excessive number of foot-pounds of energy are delivered to the insulator and through the insulator to the metallic supporting strap.

In other prior cutouts both ends of the fuseholder tube have been kept open in order to reduce the fuseholder recoil forces. However, such an expedient increases the danger of an electrical fiashover when gases are expelled from both ends of the iuseholder tube.

Lesher patents 2,574,400 and 2,574,401 assigned to the same assignee as the instant application, illustrate a compact cutout construction wherein the fuseholder tube is positioned close to the insulator without undue danger of an electrical ilashover or an excessive number of foot-pounds of energy being delivered to the insulator. However, this compact construction necessitates the use of a soiid porcelain insulator which is diicult to manufacture and costly.

It is an object of this invention to provide a compact, low cost cutout employing a hollow insulator whereby the fuseholder tube is positioned closely adjacent a side of said insulator and whereby the recoil forces imposed on said fuseholder tube are transmitted to said insulator along a line substantially coincidental with said one side to place said insulator in compression, said insulator being supported by a novel supporting means whereby danger of a fiashover between said supporting means and said fuseholder tube and other cutout hardware is minimized.

In an open type cutout comprising an elongated cylindrical hollow insulator having upper and lower terminal contact portions connected to one side of said insulator adjacent upper and lower portions thereof and a fuse tube having fusible means therein spanning and electrically connecting said terminal contact portions, said fuse tube closed at the upper end thereof and open at the lower end thereof, said fuse tube pivoted to said lower terminal contact portion adjacent said open end, my invention comprises means for supporting said cutout comprising an insulating material strap surrounding a central portion of said insulator and means for connecting said lower terminal contact portion to said lower insulator portion whereby said fuse tube is positioned closely adjacent said one side and whereby the recoil forces imposed on said fuse tube when said fusible means fuses are transmitted to said insulator along a line substantially aligned with said one side to place said insulator in compression.

The features of my invention which I believe to be novel are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing.

In the drawing,

Fig. 1 is a side View of an open type cutout embodying my invention;

Fig. 2 is a sectional View of my invention, the section being taken along the line 2 2 of Fig. l;

Figi. 3 is a sectional View along the line 3 3 of Fig. 1;

Fig. 4 is a sectional View along the line 4 4 of Fig. 1;

Fig. 5 is a sectional view along the line 5 5 of Fig. 1.

Like reference numerals in the various figures will be used to indicate similar parts.

Referring now to the drawing, and more particularly to Fig. 1, shown therein is an open type cutout or circuit interrupting device having a hollow porcelain or other insulating material support insulator i. The cutout is supported from the cross arm of a pole line or the like by a support means surrounding the central portion of the insulator I.

This support means, as seen more clearly in Fig. 2, comprises a metallic U-shaped bolt or strap 2 having an insulating material 3 bonded thereon as by molding. If so desired, strap 2 can have an insulating tape wrapped and bonded thereon, or the strap 2 can be constructed entirely out of insulating material. By the term bonded I mean an intimate moisture-tight conaeeaoie 3 tact between the metallic strap 2 and the molded insulation or tape applied thereto. If moisture is permitted to enter between the contacting surfaces of the metallic strap 2 and the insulating material thereon the insulation will be destroyed before the expected life of the cutout.

Disposed opposite the bolt 2 is another U- shaped member l. The ends of the legs of U- shaped member l have apertured ears 5 thereon extending at generally right angles from said legs away from said member 4. Said apertured ears receive the threaded ends or legs of bolt member 2. Nuts turned down on said threaded legs serve to clamp the U-shaped members 2 and Il about the insulator I.

The corners 6 at which the ears 5 and legs of member I meet are curved or rounded off. Pointed or sharp corners are intentionally avoided inasmuch as they would cause chipping of the glazed surface of the insulator I. This is also an advantage Vof using an insulating material strap. Obviously, an insulating material will be less apt to chip the glazed surface of the insulator I than a bare metallic strap.

By viewing Fig. 1 it will be apparent that when the fuseholder tube 22 is slammed shut, or when an expulsive action takes place attendant to rupture of the fusible element 21S upon overload, the insulator I will be jarred and have high stresses imposed thereon. This is cushioned by the resiliency of the insulating material 3 and U-shaped member d. Also, rocking of the insulator I is prohibited by the two line contact portions or corners 6.

Still referring to Fig. 1, it will be apparent there is danger of an electrical ashover between the central support means hardware and the other hardware portions of the cut out inasmuch as they are at different electrical potentials. Insulating the metallic strap 2, however, makes it possible for the fuseholder tube to be located `closer to the insulator I than would be possible without an insulated strap.

If an electrical flashover does occur, say between the upper terminal contact hardware I3 and Ill and the central support means hardware, the electrical arc passes therebetween around the insulator I along the surfaces thereof and generally beneath the petticoat 8 and above the insulated strap 2. Such an electrical flashover is especially destructive if vthe arc is confined in a narrow slot where the excessive heat of the arc cannot be safely dissipated. In my invention I provide vmeans for removing said excessive heat.

The insulated strap 2 which nts between a lower pettic'oat I and an upper pett'icoat or shoulder 3 has a plurality of lugs 9 protruding from the upper surface of insulating material 3 to space the insulated strap from said shoulder 8 by a gap It. Also, on the inner curved surface of insulating material 3 are formed a plurality of axial grooves I I. Should an electrical flashover occur the destructive effect of the arc will be minimized inasmuch as the heat of the arc can be dissipated 'in the area of gap I. Any carbon deposits resulting from the flashover will be effectively removed by enabling rain and the like to wash said carbon deposits out from the insulated strap area by virtue of gap iii and grooves I I.

Fastened to the upper portion of insulator I by through bolt means is an inverted U-shaped bracket I2 carrying a line terminal portion I3 and -a spring arm contact portion I4. Fastened to the lower portion of insulator I by through bolt means is an L-shaped bracket I carrying a 4 hinge element I5 having a line terminal portion I'. and a contact portion I8. The upper and lower brackets I2 and I5 and their through fastening means have certain similar features which will now be described.

From Figs. l, 3, and 4 it will be seen that the leg of brackets I2 and I5 which is in contact with the insulator I is convex and is given a smaller radius of curvature than the radius of curvature of the upper and lower portions of the insulator I. This configuration of said legs as well as the comparative slight thickness of the legs provides resiliency and line bearing contact between the insulator I and brackets I2 and I5. The side edges of the insulator contacting legs of brackets I2 and I5 are turned up or rounded off so that no sharp edges or corners will be present to chip the glaze or porcelain insulator I.

Between the inner hollow surface of the insulator I and the nuts turned down on the threaded ends of the through bolt fastening means for upper and lower brackets I2 and I5 are positioned washers. These washers have a certain amount of resiliency to absorb the shocks which would otherwise be imposed on the insulator I when the fuseholder tube 22 is slammed closed or when the cutout interrupts a severe overload.

As seen from Figs. 1, 3 and 4 the washers are generally at and the washer side edges I which are parallel to the axis of the insulator I are turned up so that the sharp side edges of the washers do not bite into the curved interior surface of insulator I. The washer side edges 2G which are perpendicular to the insulator axis are also turned up to rib the washer and thereby strengthen it, and to lock the square nuts which are used with the Washers. As seen in Figs. 3 and 4, the washers have line bearing contact with the interior surface of insulator I at curved portions 2 I.

Pivoted for opening and closing movement with respect to upper contact III is a fuseholder tube 22 closed by a contact cap 23. A fusible element 2d is in contact with contact cap 23 and extends out from the useh'older tube 22 at the lower end thereof. When so desired, a solid non-fusible metal bridging means can be substituted for fuseholder 22 as is common with devices of this type. Accordingly, my use of the term circuit interrupting device is intended to include a device with fusible or nonfusible bridging means.

As seen in Fig. 1, the fuseholder tube 22 is pivoted on the hinge element I5 by a toggle mechanism comprising a generally L-shaped hinged contact link 25 and a fuseholder tube clamp indicated generally by reference numeral One end or hinged contact link 25 is pivoted to hinge element IS at pivot point or trunnions 2: and the other end of the hinged contact link 25 is pivoted to fuseholder tube clamp 26 at pivot point or trunn'ions 28. In the unfused condition of the current responsive fusible element 2d the fuse tube 22 will be parallel to the upstanding leg or portion 29 of hinged contact link 25, as shown in Fig. l. This is because the fusible element 2 is tautly connected to the hinged contact link 25 while the fuse tube 22 and hinged contact link 25 are abutting each other.

When line leads are connected to terminals I3 and Il current will flow from terminal I3, contact I4, and contact cap 23 through fusible element 24 to hinged contact link 25. Hinged contact link 25 has a contact portion 3D which is engageable with leaf spring contact portion I8 so that current will now from the hinged contact link to contact portion I3 and terminal Il.

When an overload occurs the fusible element 24 will be fused or broken after which fuse tube 22 is free to move downwardly and outwardly about pivot point 2S away from contact IG while hinged contact link 25 is free to pivot downwardly about pivot point 2l. The contact arm or portion IB is flexed upwardly when the fuseholder tube 22 is slammed shut. Therefore, when the element 24 fuses the stored energy in flexed contact arm I4 initiates movement of the fuse tube 22 and hinged contact link 25.

When the element 24 fuses, gases are generated in fuse tube 22. These gases are expelled at high velocity out of the lower open end of the fuse tube 22 to snuff out the arc between the fused ends of the fused element 24. The recoil or reactive forces of this gaseous expulsive action tend to move the fuse tube 22 and its toggle mechanism upwardly away from hinge element IS. The bearings for trunnions 27 comprise longitudinal slots 3l in hinge element i6. Positioned between leaf spring is and the top of the hinge element I6 is spring 32 surrounding a projecting stud 320:. Accordingly, when the recoil or reactive forces tend to raise the fuse tube 22 and its toggle mechanism the trunnions 2'! will be raised in longitudinal slots SI whereupon the recoil or reactive forces are absorbed by spring 32 until it is compressed so that leaf spring It strikes projecting stud 32a, whereupon all upward movement of spring IS, the toggle mechanism, and fuseholder tube 22 is stopped. Then the recoil or reactive forces are directed along a line substantially coincidental with the side of insulator I closest to fuse tube 22 and in a direction substantially parallel to the axis of the insulator I to the strap 2 and thence U-shaped member d. With pivot point 2, contact 35, stud 32d, bracket I5 and its through fastening means substantially aligned with the side of insulator I closest to fuse tube 22 a minimum number of foot-pounds of energy or bending stresses are delivered to the insulator I. Instead, the recoil forces are transmitted to insulator i from its lower end towards its upper end whereby the insulator I is placed in compression. Accordingly, my circuit interruptor can interrupt higher fault currents than when insulator I has tension or bending stresses imposed thereon inasmuch as the porcelain of insulator I is strongest in compression. The fuse tube 22 is compactly positioned close to the right-hand side of insulator I. A line drawn through said side and the axis of fuse tube 22 will intersect at a small acute angle the apex of which is positioned close to and beneath the bottom end of insulator I. However, there is little danger of an electrical flashover to the central insulator support means hardware inasmuch as said support means comprises an insulating material strap.

Viewing particularly Fig. 5, it will be seen that the fuseholder tube clamp 26 comprises two oppositely disposed clamping bars 33. Nut and bolt assemblies hold the clamping bars clamped about the fuse tube 22. A transverse groove 34 perpendicular to the axis of the fuse tube is formed in the side of fuse tube 22 furthest removed from the insulator I. Bolt or pin 35 engages this groove to keep the fuse tube 22 from sliding axially between clamping members 33. I-Ieretofore, the groove 34 has been formed on the opposite side of the fuse tube 22 with bolt or pin 3'I engaged therewith. However, I have discovered that during the instant of current interruption the fuseholder tube 22 is severely bent and the side of the fuse tube 22 closest to the insulator I is the side most severely strained by being placed in tension. Accordingly, I have located the notch or groove 34 on the compression side of the tube 22 where it does not materially reduce the strength of the tube 22.

A porcelain or other insulating material insert 38 is positioned within the hollow of insulator I longitudinally between the upper and lower through bolt fastening means to prohibit internal electrical ashover within the hollow insulator between the upper and lower through bolt fastening means. If water from rain or the like should become trapped in the hollow of the insulator I above insert 3S, when this water is turned into ice, the expanding ice is apt to strain or fracture the upper portion of insulator I. Accordingly, instead of providing merely a cylindrical aperture in the insulator I for the upper through bolt fastening means, I form a longitudinal slot 38 which extends to the upper surface of insert 3S. Consequently, any water that enters the hollow of insulator I above insert 3S can drain therefrom via the slot 39.

While I have shown and described certain preferred embodiments of my invention, it will be obvious to those skilled in the art that changes and modications may be made without departing from the invention. I therefore airn in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. In a circuit interrupting device comprising an elongated insulator having terminal contact hardware connected to one side of said insulator adjacent opposite end portions thereof and means on said one side spanning and electrically connecting said terminal contact hardware, said spanning means positioned closely adjacent Said one insulator side, means for supporting said circuit interrupting device from a position opposite to said one side comprising a strap surrounding the central portion of said insulator, said strap constructed entirely out of an electrical insulating material.

2. .In a circuit interrupting device comprising an elongated insulator having terminal contact hardware connected to one side of said insulator adjacent opposite end portions thereof and means on said one side spanning and electrically connecting said terminal contact hardware, said spanning means positioned closely adjacent said one insulator side, means for supporting said circuit interrupting device from a position opposite to said one side comprising a metallic strap surrounding the central portion of said insulator, said metallic strap having an electrical insulating material intimately bonded thereon.

3. In a device as in claim 2, wherein said metallic strap comprises a metallic U-shaped member, the base of said U-shaped member disposed on said one side and the legs of said U-shaped member extending towards the side of said insulator opposite to said one side, said electrical insulating material comprising an electrical insulating material tape intimately wrapped about said metallic U-shaped member.

4. In a device as in claim 2, wherein said metallic strap comprises a metallic U-shaped member, the base of said U -shaped member disposed on said one side and the legs of said acca-01a 7 U-shaped membel` extending towards the side of said insulator opposite to said one side, said electrical insulating material being intimately molded about said metallic U-shaped member.

5. In a circuit interrupting device comprising an elongated cylindrical insulator having termi-V nal contact hardware connected to one side of said insulator adjacent opposite end portions thereof and means on said one side spanning and electrically connecting said terminal contact hardware, said spanning means positioned closely adjacent said one insulator side, said shoulder formed about its central portion, the diameter of said shoulder being greater than the diameter of said insulator central portion, means for supporting said circuit interrupting device from a position disposed on a side of said insulator opposite to said one side, comprising an insulated strap surrounding said insulator central portion and abutting said shoulder, said insulated strap comprising a metallic band having an insulating material intimately molded thereon, and lugs positioned on a surface of said molded insulating material opposite to said shoulder between said surface and said shoulder to space said insulated strap from said shoulder by a circumferentially extending gap.

6. In a circuit interrupting device comprising an elongated cylindrical insulator having terminal Contact hardware connected to one side oi said insulator adjacent opposite end portions thereof and means on said one side spanning and electrically connecting said terminal contact hardware, said spanning means positioned closely adjacent said one insulator side, said insulator having a circumferential shoulder formed about its central portion, the diameter of said shoulder being greater than the diameter of said insulator central portion, means for supporting said circuit interrupting device from a position disposed on a side of said insulator opposite to said one side, comprising an insulated strap surrounding said insulator central portion and abutting said shoulder, said insulated strap comprising a metallic band having an insulating material intimately molded thereon, a surface of said molded insulating material contacting said insulator central portion and having grooves formed thereon extending in a direction substantially parallel to the axis of said insulator, and lugs positioned on another surface of said molded insulating material opposite to said shoulder between said another surface and said shoulder to space said insulated strap from said shoulder by a circumferentially extending gap.

7. In a circuit interrupting device comprising an elongated hollow cylindrical insulator having upper and lower terminal contact hardware connected to only one side of said insulator adjacent upper and lower portions thereof respectively and means on said one side spanning and electrically connecting said upper and lower terminal contact hardware, said spanning means Vpositioned closely adjacent said one insulator side, said insulator having a circumferential shoulder formed about its central portion, the outer diameter of said shoulder being greater than the outer diameter of said insulator central portion, means for supporting said circuit interrupting device from a position disposed on a side of said insulator opposite to said one side, comprising an insulated strap surrounding said insulator central portion and abutting said shoulder, said insulated strap comprising a metallic band having an insulating material intimately molded thereon, a surface of said molded insulating material contacting said insulator central portion and having grooves formed thereon extending in a ydirection substantially parallel to the axis oi' said insulator, and lugs positioned on an upper surface of said molded insulating material opposite to said shoulder between said upper surface and said shoulder to space said insulated strap from said shoulder by a circumferentially extending gap.

8. In a circuit interrupting device comprising an elongated cylindrical insulator having terminal contact hardware connected to one side of said insulator adjacent opposite end portions thereof and means on said one side spanning and electrically connecting said terminal contact hardware, said spanning means positioned closely adjacent said one insulator side, means for supporting said circuit interrupting device from a position disposed on a side of said insulator opposite to said one side, comprising an insulating material U-shaped member, the base of said insulating material U-shaped member being curved and disposed on said one side and the legs of said insulating rmaterial U-shaped member extending towards said opposite side, said insulating material U-shaped member contacting substantially one half of a circumferential central portion oi said insulator, and a second U-shaped member disposed on said opposite side opposite to said insulating material U-shaped member, said second U-shaped member having two substantially parallel legs spaced from each other by la distance shorter than the outer diameter of said insulator central portion, and two ears extending from the ends or" said second U-shaped member legs in opposite directions away from said second U-shaped member and being substantially normal to said second U-shaped member legs, the legs of said insulating material ol-shaped member and said ears connected together, the corners of said second U-shaped member formed between said second U-shaped member legs and said ears being curved and making line contact with said opposite insulator side.

9. In a circuit interrupting device comprising an elongated hollow cylindrical insulator having terminal contact hardware connected to only one side of said insulator adjacent opposite end portions thereof and means on said one side spanning and electrically connecting said terminal Contact hardware, said spanning means positionecl closely adjacent said one insulator side, means for supporting said circuit interrupting device from a position disposed on a side ci said insulator opposite to said one side, comprising an insulated U-shaped member comprising a metallic st ap having an insulating rial intimately bonded thereon, the base of said insulated U- shaped member being curved an disposed on said one side and the legs ci said insulated U- shaped member extending towe said opposite side, said insulated U-shaped member contacting substantially Vone half of a circumferential central portion of said insulator, and second il-shaped member disposed on said oppo ite side opposite to said insulated U-shaped member, second U-shaped member having two substantially parallel legs spaced from each other by a distance shorter than the outer diameter of said insulator central portion, and two ears extending from the ends o1 said second U-shaped member legs in opposite directions away from said second U-shaped member and being substantially normal to said second U-shaped member legs, the legs of said insulated U-shaped member and said ears connected together, the corners of said second U-shaped member formed between said second U-shaped member legs and said ears being curved and making line contact with said opposite insulator side.

10. In a circuit interrupting device comprising an elongated hollow cylindrical insulator having upper and lower terminal contact hardware connected to only one side of said insulator adjacent upper and lower portions thereof and means on said one side spanning and electrically connecting said upper and lower terminal Contact hardware, said spanning means positioned closely adjacent said one insulator side, means for supporting said circuit interrupting device from a position disposed on a side of said insulator opposite to said one side, comprising an insulated U-shaped member comprising a metallic strap having an insulating material intimately bonded thereon, the base of said insulated U-shaped member being curved and disposed on said one side and the legs of said insulated U-shaped member extending towards said opposite side, said insulated U-shaped member contacting substantially one-half of a circumferential central portion of said insulator, and a second U-shaped member disposed on said opposite side opposite to said insulated U-shaped member, said second U-shaped member having two substantially parallel legs spaced from each other by a distance shorter than the outer diameter of said insulator central portion, and two ears extending from the ends of said second U-shaped member legs in opposite directions away from said second U-shaped member and being substantially normal to said second U-haped member legs, the legs of said insulated U-shaped member and said ears connected together, the corners of said second U-shaped member formed between said second U-shaped member legs and said ears being curved and making line contact with said opposite insulator side, and a circumferential shoulder on said insulator positioned above said insulated U-shaped member, an upper surface of said insulating material opposite to said shoulder having integral lugs thereon positioned between said shoulder and surface and spacing said insulated U-shaped member from said shoulder by a circumferentially extending gap.

1l. In a hollow cylindrical insulator having hardware resiliently connected thereto, means for resiliently connecting said hardware to said insulator comprising a bracket, through fastening means, and a washer, said bracket having a relatively thin stamped metallic part adjacent an outer cylindrical surface of said insulator and dened by two opposite side edges extending in a direction substantially parallel to the axis of said insulator, the portion of said bracket between said side edges being convex and spaced from said outer cylindrical surface, said convex portion having a radius of curvature smaller than the radius of curvature of said outer cylindrical surface, said side edges being upturned away from said cuter cylindrical surface to provide two concave portions making line contact with said outer cylindrical surface, said through fastening means passing through said spaced convex portion and said outer cylindrical surface into the hollow of said insulator, the end of said through fastening means extending into said hollow having said washer positioned thereon, said washer being substantially square-like and dat, two opposite side edges of said washer extending in a direction substantially parallel to said insulator axis and being upturned away from an interior cylindrical surface of said hollow to provide two concave washer portions making line contact with said interior cylindrical surface, two other opposite side edges of said square-like washer being normal to said insulator axis and being upturned away from said interior cylindrical surface to strengthen said washer, the central flat portion of said washer between said upturned washer side edges having an aperture therein and being spaced from said interior cylindrical surface.

l2. A circuit interrupting device comprising an elongated insulator having terminal contact hardware connected to one side of said insulator adjacent one end portion thereof and other terminal contact hardware connected to said one side adjacent an opposite end portion of said insulator, means positioned on said one side spanning and electrically connecting said terminal Contact hardware for completing an electrical circuit therebetween, said means comprising a tube having circuit opening means therein whereby expulsive gases are generated in said tube upon opening of said circuit opening means, said tube closed at one end thereof and open at the opposite end thereof whereby said expulsive gases cause said tube to recoil axially towards said closed end, said tube pivoted adjacent said open end to said other terminal contact hardware whereby the recoil forces imposed on said tube are transmitted to said insulator along a line substantially coincidental with said one side from said opposite end insulator portion towards said one end insulator portion whereby said transmitted recoil forces place said insulator in compression.

13. n a circuit interrupting device as in claim l2, wherein said tube is positioned closely adjacent said one side, said line and a line drawn through the axis of said tube intersecting at a small acute angle, and means for supporting said insulator from a position disposed on a side of said insulator opposite to said one side, said supporting means comprising an insulating materia-1 strap surrounding a central portion of said insulator.

14. .A circuit interrupting device comprising an elongated insulator having upper and lower terminal contact hardware connected to one side of said insulator adjacent upper and lower portions thereof respectively, means spanning and electrically connecting said upper and lower terminal contact hardware for completing an electrical circuit therebetween, said means comprising a fuse tube having a fusible element therein whereby expulsive gases are generated in said fuse tube upon an overload in said circuit, said fuse tube closed at the upper end thereof and open at the lower end thereof whereby said expulsive gases cause said fuse tube to recoil axially upwards towards said closed end, said fuse tube pivoted adjacent its lower end to said lower terminal Contact hardware whereby the recoil forces imposed on said fuse tube are transmitted to said insulator along a line substantially coincidental with said one side from said lower insulator portion towards said upper insulator portion whereby said insulator is placed in compression.

l5. A circuit interrupting device comprising an elongated insulator having upper and lower terminal contact hardware connected to one side of said insulator adjacent upper and lower portions thereof respectively, means spanning and electrically connecting said upper and lower terminal contact hardware for completing an electrical circuit therebetween, said spanning means comprising a fuse tube having a fusible element therein whereby expulsive gases are generated in said fuse tube upon an overload in said circuit, said fuse tube closed at the upper end thereof and open at the lower end thereof whereby expulsive gases cause said fuse tube to recoil aX- ially upwards, said fuse tube pivoted adjacent its lower end to said lower terminal Contact hardware whereby the recoil forces imposed on said fuse tube are transmitted to said insulator along a line substantially coincidental with said one side to place said insulator in compression, said fuse tube positioned closely adjacent said one side, and means for supporting said insulator from a position disposed on a side of said insulator opposite to said one side, said supporting means comprising an insulated strap surrounding a central portion of said insulator.

16. A circuit interrupting device comprising an elongated insulator having upper and lower terminal contact hardware connected to one side cf said insulator adjacent upper and lower portions thereof respectively, means spanning and electrically connecting said upper and lower terminal contact hardware for completing an electrical circuit therebetween, said spanning means comprising a fuse tube having a fusible element therein whereby expulsive gases are generated in said tube upon an overload in said circuit, said fuse tube closed at the upper end thereof and open at the lower end thereof whereby said expulsive gases cause said tube to recoil axially towards said closed end, said fuse tube pivoted adjacent its lower end to said lower terminal contact hardware whereby the recoil forces imposed on said tube are transmitted to said insulator towards said upper insulator portion along a line substantially coincidental with said one side whereby said insulator is placed in compression, said fuse tube positioned closely adjacent said one side, said line and a line drawn through the axis of said tube intersecting at a small acute angle, the apex of said angle positioned beneath the lower end of said insulator, and means for supporting said insulator from a position disposed on a side of said insulator opposite to said one side, said supporting means comprising an insulating material strap surrounding the central portion of said insulator.

17. A circuit interrupting device comprising an elongated hollow insulator having terminal contact hardware connected to only one side of said insulator adjacent opposite end portions thereof, means spanning and electrically connecting said terminal contact hardware for completing an electrical circuit therebetween, said spanning means comprising a tube having circuit breaking means therein whereby expulsive gases are generated in said tube upon opening of said circuit breaking means, said tube closed at one end thereof and open at another Dnd thereof whereby said expulsive gases cause said tube to recoil axially away from said open end, said tube pivoted adjacent said open end to one of said terminal contact hardware adjacent one of said opposite insulator end portions, and means for mounting said one terminal Contact hardware on said one insulator end portion and supporting means centrally located on said insulator for supporting said circuit interrupting device from a position disposed opposite to said one side whereby the recoil forces imposed on said tube are transmitted to said insulator along a line substantially coincidental with said one side from said one insulator end portion towards said centrally located supporting means whereby said insulator is placed in compression.

18. In a circuit interrupting device as in claim 17, wherein said tube is positioned closely adjacent said one side, said line and a line drawn through the axis of said tube intersecting at a small acute angle, said mounting means resiliently connecting said one terminal contact hardware to said one insulator end portion, and said supporting means comprising an insulating material strap surrounding a central portion of said insulator.

19. A circuit interrupting device comprising an elongated hollow insulator having upper and lower terminal contact hardware connected to only one side of said insulator adjacent upper and lower portions there-of respectively, means spanning and electrically connecting said upper and lower terminal contact hardware for completing an electrical circuit therebetween, said Spanning means comprising a fuse tube having a fusible element therein whereby expulsive gases are generated in said fuse tube upon an overload in said circuit, said fuse tube closed at the upper end thereof and open at the lower end thereof whereby said expulsive gases cause said fuse tube to recoil axially' upwards, said fuse tube pivoted adjacent its lower end to said lower terminal contact hardware, and means for resiliently mounting said lower terminal contact hardware on said one side on said lower insulator portion whereby the recoil forces imposed on said fuse tube are transmitted to said insulator along a line substantially coincidental with said one side towards said upper insulator portion whereby said one side is placed in compression.

20. In a circuit interrupting device as in claim 19, wherein said fuse tube is positioned closely adjacent said one side; and means for supporting said insulator from a position disposed on a side of said insulator opposite to said one side without substantial danger of an electrical flashover between said supporting means and said upper and lower terminal contact hardware, said mounting means, and said spanning means; said supporting means comprising an insulating material strap surrounding the central portion of said insulator.

21. A circuit interrupting device comprising an elongated hollow insulator having upper and lower terminal contact hardware connected to only one side of said insulator adjacent upper and lower portions thereof respectively, means spanning and electrically connecting said upper and lower terminal contact hardware for completing an electrical circuit therebetween, said spanning means comprising a fuse tube having a fusible element therein whereby expulsive gases are generated in said fuse tube upon an overload in said circuit, said fuse tube closed at the upper end thereof and open at the lower end thereof whereby said expulsive ga es cause said fuse tube to recoil axially upwards, said fuse tube pivoted adjacent its lower end to said lower terminal contact hardware, means for resiliently mounting said lower terminal contact hardware on said one side on said lower insulator portion whereby the recoil forces imposed on said fuse tube are transmitted to said insulator along a line substantially coincidental with said one side towards said upper insulator portion whereby said one side is placed in compression, said fuse tube positioned closely adjacent said one side, said line and a line drawn through the axis of said fuse tube intersecting at a small acute angle, the apex of said angle positioned close to and beneath the bottom end of said insulator; and means for supporting said insulator from a position disposed on a side of said insulator opposite to said one side without substantial danger of an electrical flashover between said supporting means and said upper and lower terminal contact hardware` said mounting means, and said spanning means; said. supporting means comprising an insulating material strap surrounding a central portion of said insulator.

22. A circuit interrupting device comprising an elongated hollow cylindrical insulator having upper terminal contact hardware and lower inge element hardware connected to only one side of said insulator adjacent upper and lower portions thereof respectively, means spanning and electrically connecting said upper terminal contact hardware and said lower hinge element hardware for completing an electrical circuit therebetween, said spanning means comprising a fuse tube having a fusible element therein whereby expulsive gases are generated in said tube upon an overload in said circuit, said fuse tube closed at the upper end thereof and open at the lower end thereof whereby said expulsive gases cause said fuse tube to recoil axially upwards, said fuse tube pivoted adjacent said lower open end to said lower hinge element hardware at a point positioned beneath and closely adjacent the bottom end of said insulator and means for mounting said hinge element hardware to said lower insulator portion on said one side whereby the recoil forces imposed on said fuse tube are transmitted to said insulator along a line substantially coincidental with said one side towards a central portion of said insulator, said fuse tube positioned closely adjacent said one side, said line and a line drawn through the axis of said tube intersecting at a small acute angle, the apex of said angle positioned beneath the bottom end of said insulator, and means for supporting said insulator from a position disposed on a side of said insulator opposite to said one side, said supporting means comprising an insulating material strap surrounding said central portion of said insulator, said transmitted recoil forces absorbed by said supporting means and said mounting means, said mounting `means comprising a bracket dened by two opposite side edges extending substantially parallel to the axis of said insulator, said bracket abutting said one side at said lower insulator portion, said hinge element hardware connected to said bracket.

23. A circuit interrupting device comprising an elongated hollow cylindrical insulator having upper terminal contact hardware and lower hinge element hardware connected to only one side of said insulator adjacent upper and lower portions thereof respectively, means spanning and electrically connecting said upper terminal contact hardware and said lower hinge element hardware for completing an electrical circuit therebetween, said spanning means comprising a fuse tube having a fusible element therein whereby expulsive gases are generated in said tube upon an overload in said circuit, said fuse tube closed at the upper end thereof and open at the lower end thereof whereby said expulsive gases cause said fuse tube to recoil axially upwards, said fuse tube pivoted adjacent said lower open end to said lower hinge element hardware at a point positioned beneath and closely adjacent the bottom end of said insulator and means for mounting said hinge element hardware to said lower insulator portion on said one side whereby the recoil forces imposed on said fuse tube are transmitted to said insulator along a line substantially coincidental with said one side towards a central portion or said insulator, said fuse tube positioned closely adjacent said one side, said line and a line drawn through the axis ci said fuse tube intersecting at a small acute angle, the apex of said angle positioned beneath said bottom end or" said insulator, and means for supporting said insulator from a position disposed on a side of said insulator opposite to said one side, said supporting means comprising an insulating material strap surrounding said central portion of said insulat r, said transmitted recoil forces absorbed by said supporting means, said mounting leans comprising a bracket defined by two opposite side edges extending substantially parallel to the of said insulator, said bracket abutting said one ide at said lower insulator portion, said hinge element hardware connected to said bracket, through fastening means extending through said bracket and said lower insulator portion, said point, hinge element hardware, bracket, and through fastening means being substantially aligned with said one side.

24. In a circuit interrupting device comprising an elongated insulator having two spaced terminal contact portions mounted on said insulator and means on one side of said insulator spanning said terminal contact portions to complete an electrical circuit therebetween, said means coinprising a iuseholder tube open at one end and pivoted adjacent said one end to one of said terminal Contact portions by a toggle mechanism, said toggle mechanism comprising clamping means about said fuseholder tube and a link element pivoted at opposite ends to said one terminal contact portion and said clamping means, said link element positioned between said one terminal Contact portion and the side ci said fuseholder tube closest to said one side or" said insulator and pivoted to said clamping means on the side of said useholder tube closest to said one side of said insulator, said fuseholder tube having a fusible element therein whereby expulsion gases are generated in said fuseholder tube during an overload in said circuit, said fuseholder tube having a notch therein on the side of said tube furthest removed from said one side of said insulator, said notch extending normal to the axis of said fuseholder tube, and a pin through said clamping means engaging said notch, whereby said fuseholder tube is retained from sliding axially of said clamping means.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,211,778 Steen Jan. 9, 1917 2,158,638 Schultz May 16, 1939 2,264,203 Fry Nov. 25, 1941 2,574,400 Lesher Nov. 6, 1951 2,574,401 Lesher Nov. 6, 1951

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