US3860321A - Separable electrical connectors - Google Patents

Abstract

Compound copulatory separable connector with integrated arccontrolling means adapting it for safe use as a load-break and load-make switch.

Description

United States Patent 1191 Ball 1 Jan. 14, 1975 [54] SEPARABLE ELECTRICAL CONNECTORS 2,231,576 2/1941 Grosse 200/149 A 2,267,399 12/1941 Farrer et a1.... {75] Inventor- Ball Tucker 2,363,295 11/1944 Cotter 200/163 73 Assigneez Kearney Nati0na|, Inc Atlanta, 3,272,913 9/1966 Crimmins et a1. 339/107 X 3,297,848 1/1967 Plcard et a1 200/149 R X [22] Filed: 001. 5, 1970 3,474,386 10/1969 Link 339/60 R pp No 77 913 3,512,118 2/1968 Leonard 339/60 R Related U S Application Data FOREIGN PATENTS OR APPLICATIONS [63] Continuationmpan of Sen No 7,942 Feb 2, 1970, 799,503 8/1958 Great Britain 339/111 Pat. No. 3,668,614.

Primary Examiner-Richard E. Moore [52] US. Cl. 339/111, 339/259 R All0rney,/1gent, 0r i m-P l M. Denk [51] Int. Cl ..H01r 13/52 [58] Field of Search......... 339/41, 42, 111, 60, 255, 57 AB TRACT Compound copulatory separable connector w1th Inte- 5 References Cited grated arc-controlling means adapting it for safe use as UNITED STATES PATENTS a load-break and load-make switch.

943,016 12/1909 Guett 339/41 5 Claims, 5 Drawing Figures PATENTEU JAN I FIGJ FIG.4

INVENTOR ROBERT D. BALL %6.

ATTORNEY SEPARABLE ELECTRICAL CONNECTORS CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my prior copending Ser. No. 7942, filed Feb. 2, 1970, now US. Pat. No. 3,668,614, issued June 6, 1972.

The invention relates to electrical energy disconnect devices, and particularly to load-break devices for use in systems where the voltage is or exceeds 25 Kilo volts r.m.s. with proportionately higher peak voltage.

In the 25 Kv load-break device shown and described in my copending application Ser. No. 7942, filed Feb. 2, 1970, the instrumentalities, whose manipulation effects energization or de-energization of an apparatus such as a transformer, include a male-formed conductive probe and a female-formed conductive receptor, one of which is selectively movable into and out of mating relationship with the other to make or break the continuity of an electrical circuit. In the form shown in said copending application, the probe is movable, and the receptor is stationary, but such relationship may be reversed if desired. In either event, while moving toward or away from mating relationship with the recep tor, the movable part moves along a path which is embraced by a plurality of paired arc-snuffing clappers, the members of each pair being spring biased toward each other so that when the movable part is inserted between them, the paired clappers are forced apart a distance sufficient to accommodate that part therebetween. However, when the movable part is withdrawn, the clappers are biased into flat face contact with each other, thereby mechanically pinching, and otherwise obstructing, the travel of any are which may have been drawn, as well as de-ionizing the arc gases. Each such clapper has a half-funneI-shaped mouth addressed away from the stationary part to ease the entry therebetween of the movable part during movement thereof toward the stationary part which ultimately brings them into mating relationship whereat the circuit is completed.

ln experience with such an instrumentality on 25 Kv transmission systems, it has been observed that after a number of circuit-breaking operations, the pair of clappers nearest the receptor, as well as the interior wall of their housing, became surface contaminated with a deposit of material which was at least partially conductive; and that the springs, for biasing that pair of elappers toward each other, became annealed so that they were no longer effective. This resulted in increasing the pre-strike distance during fault-close, and consequent prolongation of the pre-close arcing time.

The object of the invention is to obviate the aforesaid conductive contamination of the clappers and housing, improve the longevity of the clapper springs, and shorten the arcing time on opening or closing of the circuit, especially under fault conditions.

All facets of the above-expressed object are achieved in accordance with the invention by the combination of two changes which are minor in form, but major in effect, to wit: that the paired arc-snuffing clappers closest to the point of make and break are vented at the side adjacent said point; and that the distance between the terminus of the stationary contact and the closest point on the adjacent clappers is reduced to the minimum consistent with the provision of adequate mechanical clearance.

One embodiment of the invention, as well as its counterpart in my aforesaid prior application, is shown in the accompanying drawings, in which:

FIG. 1 is a partial sectional view of a separable connector embodying the conductive probe and receptor of my prior application, as well as the clapper, housing, and stationary contact arrangement as modified according to the present invention;

FIG. 2 is a perspective view of a clapper-spring assembly as shown in said parent application;

FIG. 3 is a view like FIG. 2, but showing the modification of the present invention;

FIG. 4 is an enlarged view of the clapper assembly and housing adjacent the stationary contact as shown in said parent application, but with the probe and other parts in a transitory position during load-breaking operation; and

FIG. 5 is a view corresponding to FIG. 4, but showing the parts as modified in accordance with the present invention.

As shown in FIG. 1, the separable portions of the connector are positioned in aligned relationship from which axial movement of the removable portion 1 into telescoping relationship with the stationary portion 2 will complete an electrical circuit between a male conductive part within portion 1 and a female conductive part within stationary portion 2. The removable portion 1 is in the form of an elbow, and is integrally connected with a semi-conductive-rubber-covered cable, about which a shielding wire is wound in accordance with the usual practice. The stationary portion 2 of the conductor is equipped with a flange 4 for mechanically mounting it upon an electrical apparatus, such as a transformer, and a stud 5 for electrically connecting it with the instrumentalities to be energized within the apparatus. As is customary with separable connectors of this general type, where, as shown, the stationary portion has a male-formed non-conductive probe of shape and size to mate with a female-shaped non-conductive member within the removable portion 1 the electrically conductive parts in each of portions 1 and 2 being arranged within the respective non-conductive members in a manner to be now described.

The removable portion 1 in the embodiment shown has an exterior sheath 6 of semi-conductive rubber, which is relatively rigid and hard, within which there is a body 7 of rubber, having substantially higher dielectric strength than does the sheath 6, and which is more resilient than the sheath 6. The interior of the body 7 is hollow to provide a cavity with a conoidal interior delineated by lines 8.

Extending axially of the conoidal cavity within body 7 is an electrically conductive probe 9, having a tip 10, and securely mounted at its other end in a conventional manner at the turn of portion 1. The tip 10 of probe 9 is preferably provided with an arc-resisting surface, such as by being made of a tungsten ring, silversoldered on the body of probe 9, or, alternatively, by being brazed with a tungsten copper alloy.

The stationary portion 2 of the connector has an exterior conoidal shield 11 of comparable high dielectric strength, resilient rubber to that of body 7. The shape and size of the male-formed shield 11 is such as to be complemental with the interior of body 7 when the separable connector portions are completely telescoped so that the conductive parts of each of the separable portions is in current transmitting relationship with those of the other. Axially centered within shield 11, there is a sub-assembly of instrumentalities, hereinafter termed the insides, all contained within a capsule 12. The capsule 12 includes two identical half-liners which are preferably molded or cast of a plastic material which is at least arc-resistant, and preferably has arcsuppressing qualities. Each such half-liner is divided into a plurality of compartments by cross-baffles 14, 15 and 16, together with end plugs 17 and 18. Baffles l and 16 are provided with central openings 19 and 20, whose diameter is about 0.025 to 0.035 inch greater than the diameter of conductive probe 9, and the same applies to channel 21 in end plug 18. In contrast, however, central hole 22 in baffle 14 preferably has a diameter of between 0.300 and 0.400 inch in excess of the diameter of conductive probe 9. The two chambers defined between the inside end wall of plug 18 and baffle 16, and between baffle 16 and baffle 15, are each designed to accommodate a pair of arc-pinching clappers of the character shown in FIG. 2, but the chamber defined between baffle 15 and baffle 14, while of the same structural design, is, in accordance with the present invention, equipped with paired clappers of the character shown in FIG. 3. Accordingly, each of the aforesaid three chambers is equipped with a pair of hollow pedestals 23, within which a clapper spring 24 is seated, and about which a clapper 25 is mounted in the upper two, but a clapper 125 is mounted in the lowermost.

The end plug 17 of the capsule 12 is contoured and proportioned to mate with the external grooving and shouldering on a conductive element 29 later to be described in detail.

The clapper elements 25 are shown in detail in FIG. 2. Each is a molded segment of a material such as melamine, which, when exposed to an electric arc, evolves gases which tend to quench that are. Each such clapper segment has a half-funnel mouth 30 which, in cooperation with the partner of its pair, guides the tip of probe 9 between the pair of clapper segments mounted in a given one of the chambers separated by baffles l5 and 16, as the probe 9 moves from its entry at channel 21 toward the connected position shown in FIG. 1. As mentioned previously, the paired clapper segments 25 or 125 are constantly biased toward each other by springs 24, the radially outer ends of which are received in a recess within the adjacent pedestal 23, while the radially inward ends of the spring are accommodated in a rebate 31, in the floor of socket 32, which accommodates a pedestal 23, and loosely interlocks the clapper element with the pedestal and spring.

As will be apparent from a comparison of FIGS. 2 and 3, each clapper 125 differs in construction in a detail which is essential to the present invention. Whereas clapper 25 is provided, on the face thereof which confronts its mate in a given pair, with a half-funnel-shaped mouth 30 which flares toward channel 21, and hence is addressed toward tip 10 of probe 9 as the latter enters the capsule l2, and clapper 125 is equipped with a duplicate thereof; clapper 125 is, in the form shown in the drawings, additionally equipped with a halffunnel-shaped mouth 130, which is addressed in the opposite direction, to wit, toward the stationary contact or receptor 29. The particular illustrated contour of mouth 130 is not critical, but the provision of a substantial recess thereat, regardless of contour, is critical to achieve the results hereinafter described; and when the clappers have planar portions (as shown) which make tangential contact with the probe, it is preferable that their mouths 130 have a maximum dimension at the end addressed toward the receptor 29 somewhat greater than the periphery of the probe.

A further structural difference between the device illustrated in said copending application and that of the present invention is apparent from the contrast between FIG. 4 and FIG. 5. In both FIG. 4 and FIG. 5, the stationary contact 29 terminates in a fingered formation 34 surrounded by a garter spring 35, all located within the capsule 12 substantially below the level of baffle 14 as shown in FIG. 4. However, in accordance with the present invention, and as illustrated in FIG. 5, the tips 36 of the fingers 34 are located below, but as close to, the baffle 14 as is feasible, e.g., with the mini mum of clearance to avoid mechanical interference when the probe 9 is being moved into or out of conductive contact within the cluster of fingers 34. By so locating the tips 36 of the fingers 34 relative to baffle 14, the arc gases generated upon load-breaking movement of probe 9 relative to fingers 34, or upon fault-closing movement in the opposite direction, are not baffled downwardly by baffles 14, but are passed freely through the opening in the latter toward the adjacent pair of clappers without substantial turbulence being created by baffle 14. Moreover, when such are gases are generated upon separation of probe tip 10 from finger tips 36, there is an exit space provided by confronting mouths 130, whereby such are gases may freely follow the movement of tip 10 instead of being obstructed by the movement, under comparable circumstances, of the corners into contiguous relationship, as shown in FIG. 4.

The curlicue hatching in FIGS. 4 and 5 illustrates the contrasting distribution of the hot arc gases upon separation of tip 10 from finger tips 36 under load-breaking conditions. In FIG. 4, it will be observed that these hot arc gases, being obstructed by the eontiguity of corners 33, in their natural tendency to follow tip 10, spread out sidewise above and below baffle 14, about and behind the clappers 25 surrounding the respective springs 24, and ultimately drift into the space between the clappers and baffle 15 with little or no flow between the faces of the clappers. On the other hand, when the escape space, provided by mouths in clappers 125, is available to accommodate the passage of these hot gases in their natural tendency to follow tip 10, they do so, and in so doing, contact with, and heating of, the springs 24 is avoided, or at least diminished. Moreover, the objectionable deposition of conductive material on the backs, as well as the confronting faces, of the clappers and the interior wall of capsule 12, is likewise avoided or diminished. As such deposition of conductive material occurs mostly when the hot gases are relatively static and cooling, and not when they are in motion as in response to the partial vacuum created by the withdrawal of probe 9, it is understandable that the faces of the clapper elements are maintained relatively clean when vents, such as the cavities 130, are provided in the clapper pair adjacent the tips 36 of the stationary conductive element 29. In the condition illustrated in FIG. 4, the baffle 14 and the eontiguity of corners 33 tend to produce turbulence in the gases and makes them spread out, whereas in the condition illustrated in FIG. 5, the escape passage provided by months 130 is conducive to stream flow of the gases, especially under load-break operation where a partial vacuum is created by quick withdrawal of probe 9.

From the foregoing description, those skilled in the art should readily understand that the invention accomplishes its objects, and provides a separable connector of the type described whose safety factor is tremendously more enduring than that of the construction shown in FIG. 4.

Of course, those skilled in the art will readily realize that the invention is not limited to the precise details of the embodiment herein disclosed, but that variations may be made therein as circumstances may require, or as preferences may indicate, without sacrifice of result or departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In a compound copulatory electrical connector for selectively connecting and disconnecting an energized electrical conductor with or from a load, said connector having separable portions, one of said portions havmg:

a. a conductive probe mechanically mounted thereto at one end and electrically connected with said conductor at the same end, said probe having a free end remote from said mounting;

b. a non-conductive open-ended receptor surrounding said probe in radially spaced relationship;

the other of said portions having:

c. a non-conductive probe having a free end with an exterior surface shaped to mate with the interior of said receptor (b);

d. a conductive receptor having an interior surface shaped to mate with the exterior of said conductive probe (a) adjacent the free end thereof, said interior surface being spaced from the free end of said non-conductive probe (0) by a distance substantially equal to but less than the length of said conductive probe (a) within said non-conductive receptor (b);

e. a pair of arc-pinching elements mounted within said non-conductive probe (c) between said conductive receptor (d) and the free end of said nonconductive probe (0), said arc-pinching elements being resiliently biased towards each other and having faces that contact to obstruct arc travel, but said elements being free for forcible movement away from each other for a distance sufficient to accommodate said conductive probe (a) between them; the improvement which comprises, said pair of arcpinching elements (e) is mounted adjacent said conductive receptor; and

f. each member of said pair has a cavity formed along an edge of its face and opening toward said conductive receptor with said cavities providing for are communication between said probe (a) and receptor (d) during insertion and withdrawal of said probe between said arc-pinching elements.

2. The combination of claim 1 wherein the distance between the opening of said cavity and the conductive receptor is not substantially greater than the clearance required for unobstructed relative movement of the respective parts.

3. In an electrical load-break having separable male and female related conductive parts, one of which constitutes a stationary contact and the other of which con stitutes a movable contact, the improvement which comprises:

i. an arc-confining member surrounding the movable contact when in engagement with, and when moving toward and away from engagement with the stationary contact;

ii. a pair of arc-quenching clappers mounted in said arc-confining member and disposed to engage said movable contact while the later is in or near engagement with the stationary contact;

iii. said clappers having faces that normally contact each other to obstruct arc travel between said conductive parts;

iv. the clappers of said pair each having a recess formed adjacent said face which is substantially concentric with said movable contact, said recesses being addressed toward said stationary contact and together delineating a mouth that provides for are communication between said conductive parts during insertion and withdrawal of said movable contact between said arc-quenching clappers.

4. The combination of claim 3 wherein the recesses in said clappers are half-funnel-shaped.

5. The combination of claim 3 wherein the respective clappers have a second recess addressed away from said stationary contact.

Claims (5)

1. In a compound copulatory electrical connector for selectively connecting and disconnecting an energized electrical conductor with or from a load, said connector having separable portions, one of said portions having: a. a conductive probe mechanically mounted thereto at one end and electrically connected with said conduCtor at the same end, said probe having a free end remote from said mounting; b. a non-conductive open-ended receptor surrounding said probe in radially spaced relationship; the other of said portions having: c. a non-conductive probe having a free end with an exterior surface shaped to mate with the interior of said receptor (b); d. a conductive receptor having an interior surface shaped to mate with the exterior of said conductive probe (a) adjacent the free end thereof, said interior surface being spaced from the free end of said non-conductive probe (c) by a distance substantially equal to but less than the length of said conductive probe (a) within said non-conductive receptor (b); e. a pair of arc-pinching elements mounted within said non-conductive probe (c) between said conductive receptor (d) and the free end of said non-conductive probe (c), said arc-pinching elements being resiliently biased towards each other and having faces that contact to obstruct arc travel, but said elements being free for forcible movement away from each other for a distance sufficient to accommodate said conductive probe (a) between them; the improvement which comprises, said pair of arc-pinching elements (e) is mounted adjacent said conductive receptor; and f. each member of said pair has a cavity formed along an edge of its face and opening toward said conductive receptor with said cavities providing for arc communication between said probe (a) and receptor (d) during insertion and withdrawal of said probe between said arc-pinching elements.

2. The combination of claim 1 wherein the distance between the opening of said cavity and the conductive receptor is not substantially greater than the clearance required for unobstructed relative movement of the respective parts.

3. In an electrical load-break having separable male and female related conductive parts, one of which constitutes a stationary contact and the other of which constitutes a movable contact, the improvement which comprises: i. an arc-confining member surrounding the movable contact when in engagement with, and when moving toward and away from engagement with the stationary contact; ii. a pair of arc-quenching clappers mounted in said arc-confining member and disposed to engage said movable contact while the later is in or near engagement with the stationary contact; iii. said clappers having faces that normally contact each other to obstruct arc travel between said conductive parts; iv. the clappers of said pair each having a recess formed adjacent said face which is substantially concentric with said movable contact, said recesses being addressed toward said stationary contact and together delineating a mouth that provides for arc communication between said conductive parts during insertion and withdrawal of said movable contact between said arc-quenching clappers.

4. The combination of claim 3 wherein the recesses in said clappers are half-funnel-shaped.

5. The combination of claim 3 wherein the respective clappers have a second recess addressed away from said stationary contact.

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