US2753541A

US2753541A - Cable connector

Info

Publication number: US2753541A
Application number: US475449A
Authority: US
Inventors: Raymond J Leonard
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-12-15
Filing date: 1954-12-15
Publication date: 1956-07-03
Anticipated expiration: 1973-07-03

Description

ully 1956 R. .1. LEONARD 2753,5411

CABLE CONNECTOR Filed Dec. 15, 1954 2 Sheets-Sheet 1 FIG. l

ATTQRN EYS ly 1956 R. J. LEONARD 2753,541

CABLE CONNECTOR Filed Dec. 15, 1954 2 Sheets-Sheet 2 INVENTOR. RAYMOND J. LEONARD ATTORNEYS iilnited States Patent i CABLE CONNECTOR Raymond 3'. Leonard, East Providence, R. I.

Application December 15, 1954, Serial No. 475,449

3 Claims. (Cl. 339-474) The present invention relates to electrical devices and more particularly to a device for effecting a connection between cables used in overhead and/or underground distribution systems.

Heret'ofore cables have been connected together by either splicing by hand and taping in the field or by utilizing various types of electrical connectors known generically as a compression type which will make a good electrical as well as mechanical connection. Today, however, electric power companies are utilizing aluminum in distribution systems, and with the utilization of this material it gives rise to several problems in splicing and terminating such aluminum cables. From a practical standpoint the connection problems have long been solved with copper cables by the utilization of various mechanical compression and even solder connectors. For aluminum, however, new techniques must be employed to assure stable, low resistance connections and up to this time have generally taken the form of compression connectors and mechanical clamp type connectors. With the latter, these connectors are generally quite bulky and do not well adapt themselves to field applications. The compression type connector has one inherent disadvantage, inasmuch as it requires carrying to the job a hydraulic press of considerable bulkincss which does not lend itself well to the installation of overhead high voltage transmission cable.

Additionally, the compression connector requires the use of an anvil and hammer to restore the connector to a straight piece from the bowed shape it assumes on crimping resulting in a considerable expenditure of time to etlect a splice. It should be pointed out that connectors that have been designed for use with copper conductors will not lend themselves for utilization with aluminum conductors, primarily due to the fact that materials that will work well with copper are generally spaced too far apart in the Galvanic table to allow their use with aluminum. Aluminum conductors are also subject to elongation under stress to a much greater degree than copper and therefore have to be manufactured in a different manner than a normal copper conductor. To this end, the wire manufacturers are providing aluminum conductors for high voltage aerial cable installation with a steel messenger cable utilized as the core for the aluminum conductor. When an aerial cable of this type is utilized with crimp connectors, two operations have to be performed, a crimp joint made on the steel messenger cable, and a separate joint on the conductors. It follows therefore that the crimp joint on the messenger is taking the full strain of the cable, which is undesirable. The present invention, therefore, contemplates the utilization of aluminum conductors of this type and provides a novel means of simple construction for effecting a connection between the aluminum cable that may be readily connected or disconnected with simple tools such as wrenches.

Another object of the present invention is to provide a novel means for dead-ending a cable or connecting two cables together where the connection between the cables is compact and may be readily protected from moisture by suitable taping thereof.

A further object of the invention is to provide an lfatented .l'uly 3, 1956 electrical conductor having a novel arrangement for connection to the inner messenger and outer electrical conductors.

A more specific object of the invention is to provide a novel combination of connector means in a single housing which will grip the steel messenger of an aluminum conductor to provide the mechanical connection and a second gripping means which will provide the electrical connection to the aluminum conductors themselves.

With these and other objects in View, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.

In the drawings:

Figure 1 is a sectional view of my invention applied to a dead-end type of connector;

Figure 2 is a sectional view taken on lines 2--2 of Figure 1;

Figure 3 is a sectional View taken on lines 3-3 of Figure 1;

Figure 4 is an exploded perspective view on the con nector shown in Figure 1;

Figure 5 is a perspective view of another form of deadend connector provided with a loop for attachment to reinforced wire holder or spool type insulator;

Figure 6 is an elevational view partially in section, showing another form of my invention, which is adapted to connect together the ends of two aluminum cables;

Figure 7 is a sectional view taken on lines '7-7 of Fig ure 6;

Figure 8 is a perspective view of the central casing of the connector shown in Figure 6;

Figure 9 is a partial sectional view of a modified arrangement for gripping the exterior of the conductor; and

Figure 10 is a partial sectional view of a. modified form of my connector, utilizing a different arrangement for engaging the steel messenger cable or inner conductor.

Referring now to the drawings, more particularly Fig ures 14, the invention in its preferred embodiment comprises a casing in that is provided with a bore 111 through out its length, one end of said bore tapering outwardly as at 12 to a mouth 13. The intermediate section 14 of said bore is made of generally uniform cross section, the other end section 15 of said bore being internally threaded to receive an attachment bolt. The external surface of the casing at the location of the bore 15 is provided with a portion which is polygonical in cross section as at 16 to present a suitable surface for the engagement of a wrench therewith although other types of surfaces could be presented as will be well understood. A portion 17 adjacent the section 16 is of reduced diameter and is provided with threads 18 to cooperate with suitable nuts.

Within the reduced section 17 of the casing 10 there are disposed two radially extending

slots

19 and 2,0. These slots 19 and 20 extend on a diameter of the casing lil and are adapted to receive two pivoted

dogs

21 and 22 which are secured by pivot pins 23, 23' and have serrated edges e. A cable gripping sleeve 24 is adapted to be inserted Within the tapered bore 12 of the casing and comprises a generally cylindrical body which is slotted or split as at 25 to provide separate fingers 26 tapered on their outer sides so that the plug 24 generally assumes a double conical frustrum formation. A nut 3d having a polygonical exterior cross section and a threaded internal bore 31 is provided to engage the threads M on the body 10. As shown more particularly in Figure 1, this nut 30 is adapted to engage the

dogs

21 and 22 and pivot them around their respective pivot pins 23, 23 at points external of the pins so that the dog 23. will turn counterclockwise as viewed in the drawing, the dog 22 turning clockwise. An end nut 32 is additionally provided and comprises a generally hollow member internally threaded as at 33 and 3 provided throughout a part of its length with a tapered bore 34, while its external surface may be tapered as at 35 and at 36 is polygonical in cross section to present a suitable surface for the engagement of a wrench therewith. The smaller end portion 37 is also pierced by an aperture 33 through which a cable may enter.

The embodiment shown in Figures l-4 is adapted to be utilized as a dead-end, and to this end is provided with a generally U-shaped suspension member dti that is attixed to the portion 16 of the casing lit by means of a bolt 41 that is received within the threaded bore fastening pin 42 is received through the open ends of the U-shaped supporting bracket 46 so that the entire assembly may be readily attached to some tie belt 413 or other supporting means.

An alternate form of dead-end construction is shown in Figure 5 in which a U-shaped bracket 5t) is provided with a bore 51 for the reception of an attaching bolt such as 41 into the bore 15 of the casing and additionally with a strap 52 which is received within two apertures 53 in the U-shaped bracket. This form of construction readily adapts the connector to various types of dead-end constructions which are utilized in terminating the ends of transmission lines to utility poles or the like.

Referring now to Figures 6 to 8, l have shown another form of connector which is particularly adapted for joining the ends of two conductors in which like parts carry the same tens and units digits in the hundred series. In this embodiment the casing 1ft) is provided with a central enlarged polygonical cross sectional section 116 and two reduced cross sectional areas 117 which are threaded as at 118. Within each of the sections 117 two pairs of radially extending slots 119 and 1% are provided with pivoted dogs 121 and 12.2, respectively. The bore through the casing 110 is identical at each end having a generally uniform section 11 and an outwardly tapering section 112 at each end thereof to form a month 113. Two nuts 13!) are provided for engagement with the threaded portions 118 to tighten down the dogs 121, 122 and two nuts 135 having the same configuration as that shown in Figure 1 are provided for each end of the body. Within the tapered sections 134 of the nut 135 and the tapered section 112 of the body 110 there is adapted to be received a cable gripping sleeve 124 which is provided with longitudinally extending slots resulting in separate gripping fingers 126.

A slight modification of my connector is shown in Figure 9 in which like parts bear like reference numerals to the embodiment of Figure l with a prime. In this disclosure the cable gripping sleeve has been sli htly modified and appears as a single conical frustrum 24' which seats in the tapered bore 12.. The nut 35' in this instance is provided with an interior wall 39 that will abut the sleeve and force it into the bore 12. All other parts are identical to the previously described structures.

A still further modification of my construction is shown in Figure in which like reference numerals will identify like parts in the first two embodiments in the two hundred series. The slot 2 herein has been omitted along with its co-operating dog 22. This therefore results in the bore 214 being solid opposite the slot 219 so that the one remaining dog 22!. urges the gripping strand of the cable against this abutment provided by the bore. Nut 23 3, as previously, tightens the dog ml by pivoting it about pin 223 forcing the serrated edge 221 into contact with the strand 6% of the cable.

In the use of this device a short section of the conductor is reduced in diameter, preferably by removing the outer stranded aluminum conductors and leaving only the steel messenger strand 60. The out 35 is then slipped over the conductor with its threaded bore 33 extending toward the reduced section, and the cable gripping sleeve 24 is slipped over the outside of the cable conductor. The steel messenger strand 6t is then inserted within. the bore of the body 10 so that it abuts the ends of the bore 14.

4 Nut 30 is then tightened to pivot the

dogs

21 and 22 on their pins 23, 24, which swings their arcuate serrated edges 2 into gripping relation with the steel messenger strand or reduced section 60. After the nut 30 has been completely tightened, the cable gripping sleeve may be inserted into the tapered bore 12 and the nut 35 threaded onto the portion 18. As is well known, when the nut 35 is tightened, the two tapering bores 12 and 34 as shown in Figures l-7 or the single bore 12 of Figure 9 will force the gripping fingers 26 of the slotted cylindrical sleeve 24 into firm contact with the outer surface of the conductor. Any longitudinal outward pull upon the conductor operating to increase the gripping power of the fingers thereon. It should be noted at this point that with the utilization of aluminum conductors, surface oxide may cause a high resistance contact due to the formation of a film on the surface of the aluminum conductor. If. this film is light, the compression of the fingers 26 onto the exterior surface of the cable will be sufficient to make a good electrical bond. However, to assure a good electrical contact, the oxide should be bro-ken down by using a joint compound especially devised for that purpose. Generally these joint compounds contain such things as metallic zinc particles which will form current carrying bridges across the contact surfaces and prevent further oxidation of the contact surfaces. it also can be readily appreciated that the cable gripping plug 24 may take various forms as is well known in the art. For instance, any of the forms that are shown in the Becker Patent No. 1,267,959 will be suitable for gripping the external conductor to make a firm electrical bond and may be combined with the modification of Figure 9. The preferred material for the construction of this electrical connector for use with aluminum conductors would, of course, be aluminum so that no galvanic action may take place between the connector and the conductor itself. The

dogs

21, 22, however, must be of a hardened material such as steel, which has been found to cooperate very readily with the aluminum casing to provide a very workable unit.

I claim:

1. A connecting device for stranded electric conductors comprising a casing having a bore therethro-ugh, said bore having an end section tapering outwardly toward the mouth thereof, at least one pivoted dog in said bore adjacent said tapering end section, said dog co-operating with'a means diametrically opposite the dog to firmly grip at least one of the strands of said conductor, a split cylindrical sleeve having a complementary tapered surface to the tapered surface of said bore adapted to grip the exterior of the stranded conductor, means to engage said dog and pivot the same into gripping relation and separate means to tighten said sleeve.

2. A connecting device for stranded electric conductors comprising a casing having a bore therethrough, said bore having an end section tapering outwardly toward the mouth thereof, two pivoted dogs in said bore extending on a single diameter thereof adjacent said end section, said dogs co-operating with each other to firmly grip at least one of the strands of the conductor, a. split cylindrical sleeve having a complementary tapered surface to the tapered surface of said bore adapted to grip the exterior of the stranded conductor, and means to engage said dogs and tighten said sleeve.

3. A connecting device as in claim 2 wherein the dogs extend through slots in said casing and have portions thereof extending beyond the external diameter thereof, and a nut threadingly engages the exterior of said casing to pivot the dogs into engagement with at least one of said strands.

Staub May 22, 1934 Berndt Jan. 5, 1954