US2694120A - Load break device - Google Patents

Description

Nov. 9, 1954 R. NAKATA ETAL LOAD BREAK DEVICE 2 Sheets-Sheet 1 Filed July 21, 1953 n J Sah n i w is %NRWA v1 r o? a I u h S VJT b M a \O ,4, H a 3 Nov. 9, 1954 R. NAKATA ETAL LOAD BREAK DEVICE 2 Sheets-Sheet 2 Filed July 21, 1953 Fig 5.

,2.- IIIECI l! Inventors.

Ro Nakat Eidney R. smith Jr: by fiM M Their Att own e y.

United States Patent Ofifice 2,694,120 Patented Nov. 9, 1954 LOAD BREAK DEVICE Roy Nakata, Schenectady, N. Y., and Sidney R. Smith, Jr., Stockbridge, Mass., assignors to General Electric Company, a corporation of New York Application July 21, 1953, Serial No. 369,468

9 Claims. (Cl. 200-113) This invention relates to a load break device, and more particularly, to a load break device for open or enclosed type cutouts.

Open or enclosed type cutouts comprise two stationary terminal contact portions with a pivotally mounted fuseholder assembly spanning and electrically connecting said stationary terminal contact portoins. The fuseholder assembly has upper and lower contacts thereon engageable with the two stationary terminal contact portions. To break the load, as when it is desired to repair electrical equipment, the fuseholder assembly can be pivoted open to disengage the fuseholder assembly contacts from the stationary terminal contact portions. However, in such a procedure there is heavy arcing between the stationary terminal contact portions and the fuseholder assembly contacts during their separation, and this arcing decreases the life of the stationary terminal contact portions and the fuseholder assembly contacts.

Also, arcing between the stationary terminal contact portions and the fuseholder assembly contacts may persist for a relatively long period after the fuseholder assembly is pivoted open, constituting a safety hazard to the lineman operating the cutout. The are tends to be moved about by wind or air currents and may initiate a major short circuit between the line conductors or other parts of the apparatus. The resultant high current, high voltage, short circuit arc, in addition to causing a shutdown in electric service, can cause damage to the equipment.

It is an object of this invention to provide a low cost load break device whereby the load current of an open or enclosed type cutout may be interrupted with safety to the lineman and without hazard of service interruption or damage to the line apparatus.

It is a further object of this invention to provide a load break device for an open or enclosed type cutout whereby the load is broken by said device exteriorly of said cutout without arcing between the cutout contacts attendant to separation of said cutout contacts.

Our invention comprises an electrical insulating material fuse tube having a metallic stationary arm connected at one end thereof to one end of said fuse tube, said stationary arm projecting away from a side of said fuse tube, and another metallic arm pivoted at one end thereof to the other end of said fuse tube, said arms projecting from the same side of said tube and lying in substantially the same plane, said pivoted arm pivotal towards and away from said stationary arm and spring biased towards said stationary arm and same side, the projecting ends of said arms having opposed hook portions, and means within said fuse tube electrically connected to said arms and adapted to interrupt an electric circuit through said arms and means.

The invention will be better understood by considering the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the drawings Fig. 1 is a schematic illustration of the electrical relationship between one form of our invention and an enclosed type cutout. Fig. 2 is a view in perspective of an enclosed type cutout and the manner of connecting our said one form of invention adjacent thereto. Fig. 3 is a side view of our said one form of invention. Fig. 4 is a side view, partly in section, of another form of our invention. Fig. 5 is a sectional view of said another form of our invention, the section being taken along the line 55 of Fig. 4.

Referring now to the drawings for an explanation of one form of our invention, and more particularly to Figs. 1 to 3, shown therein is an enclosed type cutout 10. Such a form of cutout comprises, as seen from Fig. 1, an upper and lower stationary terminal contact portion 11 and 12, respectively, and a fuseholder or fuse tube 13 mounted on a door 14. The fuseholder 13 has upper and lower contact portions 15 and 16, respectively, engageable with upper and lower stationary terminal contact portions 11 and 12, respectively. Line leads 17 and 18 are brought into a side of cutout 10 through appropriate openings therein, and said leads 17 and 18 are connected to terminals 11 and 12, respectively. A fuse link, not shown, having a fusible element is located within fuseholder or fuse tube 13 and is electrically connected at opposite ends to contacts 15 and 16. As is well known in the art, the fuse link will fuse or rupture when an overload occurs on the line. The fuse tube 13 is constructed out of electrical insulating material adapted to evolve an eletcrical arc extinguishing gas when subjected to an electrical are for extinguishing the are drawn between the ruptured ends of the not shown fuse link within fuse tube 13. Also, fuseholder 13 is pivoted as at 19 so that the cutout contacts can be separated or engaged attendant to pivotal opening or closing of the door 14, respectively.

To break the load, as when it is desired to repair electrical equipment, the door 14 may be hinged open. However, such a method of breaking the load causes heavy arcing between the cutout contacts. Heavy arcing is undesirable since it deteriorates the cutout parts, represents a safety hazard to the lineman, and may cause a major short circuit.

Accordingly, in our invention we provide a load break device to be used in conjunction with the cutout 10 so that when the door 14 is hinged open there is no arcing between the cutout contacts and the load is broken exteriorly of the cutout by the load break device.

The load break device comprises a fuseholder or fuse tube 20 having a metallic contact portion 21 and a metallic contact arm 22 positioned at one end thereof, and a metallic contact portion 23 and a metallic contact arm 24 positioned at the other end thereof. The upper arm 22, which preferably is integral with contact 21, is electrically connected to upper contact portion 21, and is stationary and projects away from fuse tube 20 preferably though not necessarily at substantially right angles to a side thereof. Connected to an opposite side of contact 21 and projecting away from fuse tube 20 in a direction opposite to that of arm 22 is a switchstick receiving portion 25.

The lower contact portion 23 has two spaced parallel metallic integral bearing portions 26 and 27 with a metallic bearing pin 28 passing perpendicularly through bearing portions 26 and 27. On pin 28 between bearing portions 26 and 27 is pivotally mounted metallic contact arm 24. The arms 22 and 24 project from the same side of fuse tube 20 and lie in substantially the same plane. The pivoted arm 24 is pivotal towards and away from arm 22 and is spring biased toawrds stationary arm 22 and said same side by a metallic spring 29.

The spring 29 is wound around pin 28 between bearing portion 26 and the pivoted end of arm 24. The bearing portion 27 is made somewhat longer than bearing portion 26 to provide a plane bearing surface for the side of arm 24 facing opposite said bearing portion 27, and the coiled portion of spring 29 exerts an axial force along pin 28 to force the pivoted end of arm 24 against said plane bearing surface.

One end 30 of spring 29 bears against contact portion 23 and the other end of spring 29 bears against a bottom edge of arm 24. Said other end of spring 29 has an arm portion 31 which extends parallel to the axis of pin 28. See Fig. 2. This arm portion 31 engages the bottom edge of arm 24 to bias said arm 24 towards stationary arm 22. However, spring arm portion 31 will bias arm 24 towards arm 22 at an angle of only approximately with respect to fuse tube 21) inasmuch as spring arm portion 31 can also engage edge 32 of bearing portion 27. See Fig. 3.

The projecting ends of arms 22 and 24 have opposed notched hook portions 33 and 34, respectively. The

method of positioning the load break device in cooperative relationship with cutout 10, as shown in Fig. 2, is to place hook portion 34 of lower pivoted arm 24 into engagement with lower line lead 18. The cutout 10 can be reached by positioning the load break device on a switchstick 35, the switchstick socket portion 25 of the load break device being adapted to receive said switchstick 35. After hook portion 34 is hooked on line lead 18 the load break device is pushed upwardly. An upward thrust on the load break device causes arm 24 to pivot away from arm 22 against the action of spring 29, whereby the distance between arms 22 and 24 is increased sufficiently for hook portion 33 of arm 22 to engage upper line lead 17. The switchstick 35 can be removed from portion 25 after hook portions 34 and 33 engage, respectively, line leads 1% and 17 inasmuch as spring 29 will cause arms 24 and 22 to move towards each other to firmly hook the load break device on the line leads 1% and 17. Since line leads 1'7 and 18 are brought into the cutout 10 for electrical contact with the terminals 11 and 12, the ends of leads'17 and 18 exterior to the side of the cutout iii are usually bare of insulation. If this is not so, the leads l7 and 13 can be bared for electrical contact with the load break device arms.

It will be obvious that our load break device can be used with cutouts having different sizes. That is, our invention is not limited to use with cutouts wherein the distance between line leads 17 and i8 is fixed. Because the arm 24 is pivoted, the distance between arms 22 and 24 can be automatically varied to fit differently spaced line leads l7 and 18.

Within the fuse tube 20 is a fuse link 36, having a not shown fusible portion, connected at one end to contact 21 by a fuse tube cap 37, as is well known in the art; and at the other end to contact 23 or arm 24, as at metallic fuse link fastening portion 38. The upper end of fuse tube 20 is closed by cap 37 and the lower end of fuse tube 20 is open so that the fuse link 36 can be brought out of fuse tube 20 for connection to portion 38 Referring to Fig. 1, it will be seen that the fuse link 36 and the fuse link, not shown, in fuse tube 13 of the cutout 19 are connected electrically in parallel. The load break device fuse link 36 is selected to have a rating such that it will fuse when carrying the full load after door 14 is opened. When the door 14 of the cutout 10 is swung open to separate the cutout contacts there will be no arcing therebetween, and almost instantaneously the fuse link 36 will fuse or rupture whereby the load is broken at the load break device. The fuse tube 20 is constructed out of an electrical insulating material adapted to evolve an electrical arc extinguishing gas when subjected to an electrical arc whereby the arc drawn between the ruptured ends of fuse link 36 is extinguished.

Thus, we have provided a load break device for effectively preventing arcing at the cutout contacts. Also, our load break device is low in cost, has relatively few parts, and is compact. For instance, the pivoted arm 24 can be swung towards stationary arm 22 to a position substantially parallel to fuse tube 20. In such a collapsed condition of the load break device, a lineman can conveniently place the device into one of his pockets while he is working on a pole, line or the like.

Referring now to' Figs. 4 and for a description of another form of our invention, it will be seen that this form of invention is substantially similar to the form of nvention shown in Figs. 1 to 3, except for the circuit interrupting means within the fuse tube. Thus, the load break device comprises a fuseholder or fuse tube 44) having an upper metallic contact portion 41 with a stationary metallic contact arm 42 and a switchstick receiving portion 43 electrically connected to said contact portion 41.

The lower end of fuse tube 40 has a lower metallic contact portion 44 with a pivoted metallic contact arm 45 electrically connected thereto. The contact portion 44 has parallel spaced bearing portions 46 and 47 carrying bearing pin 48 on which is pivotally mounted one end of pivoted arm 45. The arms 42 and 45 project from the same side of fuse tube 45) and lie in substantlally the same plane. The arm 45 is pivotal towards or away from arm 42 and is spring biased towards arm 42 and said same side by spring 49.

The circuit interrupting means within fuse tube 40 is similar to the insulator follow rod means disclosed in Reissue 22,744 issued April 9, 1946, to S. R. Smith, Jr., a coinventor herein, and assigned to the same assignee as the instant application. Thus, a flexible braided conductor 50 has at one end thereof a button head 51 placed in electrical contact with contact portion 41 by fuse tube cap 52 and a spring positioned between cap 52 and contact portion 41. The other end of braided conductor 50 is connected to a movable cylindrical contact portion 53 which has a circumferential notch or groove therein. Connected to the movable cylindrical contact portion 53 is an electrical insulating material follow rod 54. A spring 55 within fuse tube 40 is adapted to draw contact portion 53 and insulating follow rod 54 within fuse tube 40 when contact portion 53 is released by a trigger mechanism to be described hereinafter. When the insulating rod 54 is in its fully withdrawn position the contact portion 53 will partially protrude from the lower open end of fuse tube 40. Inward movement of the contact portion 53 and insulating rod 54 is stopped at about midway of fuse tube 49 by a liner 56 inside fuse tube 40 which extends to about the central portion of fuse tube 49.

The trigger mechanism for releasing movable contact portion 53 and insulating follow rod 54 for inward movement comprises two bearing portions 57 and 58 connected to lower contact portion 44 and traversed by a bearing pin 59. On bearing pin 59 is pivotally mounted a trigger finger or lever 60 biased by a spring 61. When the insulating rod 54 is withdrawn the spring 61 will bias the lower end of trigger finger or lever 60 into engagement with the circumferential groove in movable cylindrical contact portion 53 to hold said contact 53 and insulating rod 54 withdrawn from fuse tube 40, as shown in Fig. 4. In this condition of the load break device an electrical circuit is established from stationary arm 42 through conductor 50 to contact 5.3 and trigger gigger 60, and thence to contact 44 and pivoted arm As in the Figs. 1 to 3 form of invention, the projecting ends of arms 42 and 45 have opposed hook portions 62 and 63, respectively, which will engage the line leads 64 and 65 which are connected to terminal portions of a cutout, not shown. With the insulating rod 54 withdrawn and an electrical circuit established through the load break device between line leads 64 and 65, the cutout contacts may be disengaged without any arcing therebetween. After the cutout contacts are disengaged the whole load is carried by the load break device and the load may be broken at the load break device by depressing the upper end of trigger finger 60. Depression of the trigger finger 60 releases the movable contact 53 and insulating rod 54 for movement within fuse tube 40. The fuse tube 40 and insulating rod 54 are constructed of electrical insulating material which evolves an electrical arc extinguishing gas when subjected to the heat of an electrical arc. The contact 53 and insulating rod 54 have an external diameter slightly less than the internal diameter of fuse tube 40 to define an annular space therebetween when the contact 53 and insulating rod 54 are drawn into fuse tube 40. As the contact 53 and insulating rod 54 are drawn into tube 40 an arc is struck between the contact 53 and the lower end of trigger finger 60 or contact portion 44. This are is drawn into said annular space and gas evolved by the fuse tube 49 and insulating rod 54 extinguishes this arc.

While there have been shown and described particular embodiments of the invention, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention, and that it is intended by the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

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

l. A load break device comprising an electrical insulating material tube, a stationary metallic arrn fixed at one end thereof on one end of said tube and projecting away from said tube at substantially right angles thereto, another metallic arm mounted at one end thereof on the other end of said tube for pivotal movement, said arms lying in substantially the same plane and projecting from the same side of said tube, said pivotal arm being spring biased towards said stationary arm and said same side, the projecting ends of said arms each having opposed hook portions, and electrically conductive means within said tube electrically connected at opposite ends to said arms for interrupting an electric circuit through said arms and means.

2. A load break device comprising an electrical insulating material tube, a stationary metallic arm fixed at one end thereof on one end of said tube and projecting away from said tube at substantially right angles thereto, another metallic arm mounted at one end thereof on the other end of said tube for pivotal movement, said arms lying in substantially the same plane and projecting from the same side of said tube, said pivotal arm being spring biased towards said stationary arm and said same side, electrically conductive means within said tube electrically connected at opposite ends to said arms for interrupting an electric circuit through said arms and means, the projecting end of said arms each having opposed hook portions, and a switchstick socket on said tube adapted to receive a switchstick whereby said load break device may be hooked on or detached from two line leads by means of said switchstick, said switchstick socket positioned on a side of said tube opposite to said same side.

3. A load break device comprising an electrical insulating material tube having metallic contact portions at opposite ends thereof, the contact portion at one end of said tube having a stationary metallic arm projecting therefrom at substantially right angles to said tube, and the contact portion at the other end of said tube having two parallel spaced bearing portions extending therefrom with a bearing pin passing through said bearing portions, another metallic arm pivoted at one end thereof on said pin between said bearing portions for pivotal movement towards and away from said stationary arm, said arms projecting from the same side of said tube and lying in substantially the same plane, said pivoted arm being spring biased towards said stationary arm and said same side, the projecting ends of said arms having opposed hook portions, and electrically conductive means Within said tube electrically connected to said contact portions for interrupting an electric circuit through said arms and means.

4. In a load break device as in claim 3, wherein said tube is open at said other end thereof and said electrically conductive means comprises a fuse link having a fusible portion, said fuse link connected at one end to the contact portion at said one end of said tube and at the other end to said pivoted arm.

5. In a load break device as in claim 3, wherein said tube is open at said other end thereof and said means comprises a flexible cable within said tube connected at one end to said contact portion at said one end of said tube and having connected to its other end a cylindrical notched contact followed by an electrical insulating material rod, said tube having a spring therein adapted to pull said cylindrical notched contact and said electrical insulating material rod into said tube, and a spring biased trigger contact mounted on the contact portion on said fuse tube other end engageable with a notch in said cylindrical notched contact for holding said electrical insulating material rod withdrawn from said tube.

6. A load break device comprising an electrical insulating material tubular member, a stationary metallic contact arm rigidly connected at one end thereof to one end of said tubular member and projecting substantially perpendicularly from said tubular member, another metallic contact arm pivoted at one end thereof to an opposite end of said tubular member, said arms projecting from a same side of said tubular member, said pivoted arm pivotally movable towards and away from said stationary arm and said same side, a spring biasing said pivoted arm towards said stationary arm and said same side, and opposed hook portions formed in the other ends of said arms whereby said load break device can be hooked on to any one pair of a plurality of pairs of differently spaced electrical conductors.

7. A load break device comprising an electrical insulating material tubular member, a stationary metallic contact arm rigidly connected at one end thereof to one end of said tubular member and projecting substantially perpendicularly from said tubular member, another metallic contact arm pivoted at one end thereof to an opposite end of said tubular member, said arms projecting from a same side of said tubular member, said pivoted arm pivotally movable about said one end thereof towards and away from said stationary arm and said same side, a spring continuously biasing said pivoted arm towards said stationary arm and said same side until said pivoted arm is disposed with respect to said same side at an angle of approximately 60 degrees therebetween, and opposed hook portions formed at the other ends of said arms, whereby said arms can embrace any one pair of a plurality of pairs of differently spaced electrical conductors therebetween to retain said tubular member in spanning relationship with respect to said any one pair.

8. A load break device comprising an electrical insulating material tube, a stationary metallic arm fixed adjacent one end thereof adjacent one end of said tube and projecting away from a side of said tube, another metallic arm mounted adjacent one end thereof adjacent another end of said tube for pivotal movement, said arms lying in substantially the same plane and projecting away from a same side of said tube, said pivotal arm being spring biased towards said stationary arm and said same side, opposed hook portions adjacent the projecting ends of said arms, and electrically conductive means within said tube electrically connected adjacent opposite ends thereof to said arms for interrupting an electric circuit through said arms and means.

9. A load break device comprising an electrical insulating material tubular member, a stationary metallic contact arm rigidly connected at one end thereof to one end of said tubular member and projecting away from a side of said tubular member, another metallic contact arm pivoted at one end thereof to an opposite end of said tubular member, said arms projecting from a same side of said tubular member, said pivoted arm pivotally movable towards and away from said stationary arm and said same side, a spring biasing said pivoted arm towards said stationary arm and said same side, and opposed hook portions formed in the other ends of said arms whereby said load break device can be hooked on to any one pair of a plurality of pairs of differently spaced electrical conductors.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Pittman et a1. Jan. 10, 1933

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