US3771112A

US3771112A - Cable splice clamping and bonding assembly

Info

Publication number: US3771112A
Application number: US00242128A
Authority: US
Inventors: J Thompson; G Gillemot
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-04-07
Filing date: 1972-04-07
Publication date: 1973-11-06
Anticipated expiration: 1990-11-06

Abstract

A cable splice clamping and bonding assembly for use with a pair of shielded cable ends, at least some conductors of which are to be spliced together. A length of each cable sheath is removed to expose a short ringlet of the metallic shield with ringlets firmly and securely clamped together in overlapping relation crosswise of a non-wrenchable split bolt connector. The connector clamping ring lacks wrench engaging surfaces but is roughened to facilitate tightening of the connector solely by finger pressure without risk of damage to the foil-like cable shields or to the underlying conductors. The connector bonds the shields together and transfers stresses directly between the main bodies of the two cables without risk of strain on the conductor splice connections.

Description

United States Patent 1 Thompson et [111 3,771,112 [451 Nov.-6, 1973 CABLE SPLICE CLAMPING AND BONDING ASSEMBLY [76] Inventors: John T. Thompson, 244 Loring St.,

Los Angeles, Calif. 90024; George W. Gillemot, 2331 20th St., Santa Monica, Calif. 90405 22 Filed: Apr. 7, 1972 21 Appl. No.: 242,128

Related US. Application Data [63] Continuation of Ser. No. 884,874, Jan. 26, 1970, abandoned, which is a continuation-in-part of Ser. No. 797,943, Feb. 10, 1969, abandoned.

[52] US. Cl 339/244 B, 24/125 R, 339/249 B,

' 339/265 R, 339/276 R [51] Int. Cl I-l0lr 11/10 [58] Field of Search 339/244 B, 249 B,

339/265, 272 B, 276, 268; 24/125 R, 135 R [56] References Cited UNITED STATES PATENTS 634,766 10/1899 Roche 339/272 B 3,093,435 6/1963 Johnson 339/276 R FOREIGN PATENTS OR APPLICATIONS 1,249,301 1l/,l960 France 339/272 B 590,209 1] 1960 Canada 339/249 B 1,034,285 7/1973 France 24/125 R 873,277 3/1942 France 339/272 B 987,262 4/1951 France 339/244 B 113,438 l/1926 Switzerland. 339/272 B 774,182 9/1934 France 339/272 B 537,248 6/1941 Great Britain 339/244 B 212,653 5/1967 Sweden 24/125 R Primary ExaminerJoseph H. McGlynn Attorney-Wm. Douglas Sellers et al.

[5 7] ABSTRACT A cable splice clamping and bonding assembly for use with a pair of shielded cable ends, at least some co'nductors of which are to be spliced together. A length of each cable sheath is removed to expose a short ringlet 3 Claims, 10 Drawing Figures expensive construction easily assembled over the exposed shields of a pair of shielded cables being spliced together.

Many proposals have been made heretofore for providing an electrical junction with a protective enclosure but such proposals are subject to numerous disadvantages and shortcomings avoided by thepresent invention. The problem involves provision of easily assembled components capable of being fitted together about an electrical junction to provide an insulated weatherproof enclosure for the junction. Prior constructions are characterized by their complexity and excessive number of costly components, which are timeconsuming to assemble about a junction. Many of these prior expedients are lacking in versatility to accommodate a range of wire sizes and for use under the widely differing, commonly encountered operating conditions. By way of example, reference is had to the common experience of having to repair an underground utility service connection between the main line and a service outlet after this service connection has been severed accidentally by workmen doing excavation or the like work. Repair of the broken connection without uncovering long lengths of the service connection requires splicing in a short length of connector cabling. Thereaf- -ter, this longer than-normal splice must be suitably enowing to the thinness and very low strength of the foil.

It is, therefore, a primary purpose of the present invention to provide a simple, rugged, inexpensive encapsulating assembly which is highly versatile and adaptable to widely varying conditions and operating environments and by the use of which electrical splices and junctions can be protected indefinitely from the elements. These objectives are achieved using several novel expedients including a simple non-wrenchable connector to anchor the main bodies of the overlapped cable ends together with exposed portions of their electrical shielding layers in direct bonding contact and, if desirable, to a grounding wire. Another important feature is the provision of a splice assembly enclosure comprising a length of high-durability plastic tubing capable of withstanding shock, abusive handling, and adverse atmospheric conditions likely to be encountered in normal use. A single valved opening for potting compound suffices for shorter embodiments of the tubular shroud, whereas two or more such openings are desirable in shrouds for longer splices. The potting compound completely surrounds the shielding connector and positively locks its mated threads against loosening from vibration, temperature changes and other adverse factors.

Accordingly, it is a primary object of the present invention to provide a simple, inexpensive, nonwrenchable lightweight, substantially indestructible split bolt assembly to clamp the overlapped main bodies of a pair of shielded cables finnly bonded together at exposed areas of their shield jackets.

Another object of theinvention is the provision of unique non-wrenchable connector in combination with the overlapped ends of a plurality of shielded cables to provide a strong and durable electrical connection between their shielding shrouds and additionally effective to protect the individual splices from stresses acting lengthwise of the cables proper at a splice junction.

Another object of the invention is the provision of a non-wrenchable mechanical connector for electrically interconnecting cable shielding shrouds and for 'anchoring grounding wiresthereto without need for tools and without risk of rupturing or damaging the shielding shroud.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawings to which they relate.

Referring now to the drawings in which preferred embodiments of the invention are illustrated:

FIG. 1 is a side view of one illustrative embodiment of the invention fully assembled and sealed;

FIG. 2 is a cross-sectional view on an enlarged scale taken along line 2-2 on FIG. 1;

FIG. 3 is a cross-sectional view of FIG. 2 from one end thereof; I

FIG. 4 is a cross-sectional view'taken along line 4-4 on FIG. 2;

FIG. 5 is a cross-sectional view through a second preferred embodiment of the invention in assembled condition;

FIG. 6 is a side view of a second preferred embodiment of the invention fully assembled;

- FIG 7 is a longitudinal sectional view taken along line 77 on FIG. 6;

FIG. 8 is a cross-sectional view on an enlarged scale taken along line 8-8 on FIG. 7;

FIG. 9 is a side view of a second embodiment of the shank component of the invention non-wrenchable connector; and

FIG. 10 is a side view of another embodiment of the non-wrenchable connector.

Referring initially more particularly to FIGS. 1 to 4, there is shown an exemplary embodiment of the invention encapsulating assembly, designated generally 10, having a plastic main body tube 12 open at either end and normally closed by snug-fitting

plastic caps

13, 14. Tube 12 is preferably made of transparent, tough, and highly durable plastic composition, the transparency enabling workmen to check the position of the splice during the final assembly operation, and in particular, to note whether there is any trapped air present during the final stages of the potting operation.

- A polycarbonate thermoplastic composition is partic- I ularly suitable because of its many advantageous properties under the environmental conditions encountered in the use of the invention assembly. Among these desirable properties is its high impact and dielectric strength, excellent heat resistance and stability and outstanding ability to form a permanent high strength bond with epoxy and other commonly used potting compound. In longer versions of the encapsulating assembly, as shown in FIGS. 1 and 2, it is desirable to provide main body tube 12 with two or more charging slots 16, 17,18, the number depending on the length of tube required to enclose the splice. These slots are preferably elongated lengthwise of the main body and equipped with a valve movable between open and closed position relative to an associated charging openmg.

A preferred valve construction comprises one or more split plastic sleeves, such as those indicated at 20 and 21 in FIGS. 1, 2 and 4. As there shown, sleeve 20 is sufficiently long to provide a common closure for both of the charging openings 16 and 17. Valve 21, on the other hand, controls only the single charging slot 18. Each of the valve sleeves 20, 21 is constructed simi larly from the same transparent plastic material as tube 12 and having a snug sliding fit over the exterior of the latter. A narrow strip of each sleeve is removed throughout its length as is indicated at 22 in FIG. 4, the portion removed having a width at least as great as the width of the charging slot. Accordingly, when the valve sleeve is in open position, the gap overlies an associated one of the charging slots so that the latter is unobstructed.

End caps

13, 14 for the main shroud tube are generally cup-shaped and molded from semi-rigid slightly resilient and pliant plastic material. The interior dimensions of these caps are selected to have a snug or press fit with'the exterior of tube 12. The bottom portion of the end caps is provided with at least one and preferably a plurality of stepped or tapering tubular extensions 25 closed at their smaller diameter ends. As herein shown, the tubular extensions 25 are stepped to provide at least two generally cylindrical portions of different diameters to accommodate wire or cabling of different sizes. Preferably the plastic material has limited resiliency andcapability of stretching to have a snug fit with a slightly larger conductor. Alternatively, tubular extensions 25 may be of frusto-conical configuration. In all configurations, it will be understood that any portion of the extension may be severed at an appropriate point along its length depending upon the size of the conductor to be accommodated.

A typical use of the invention encapsulating assembly cited by way of illustration only is to repair a severed utility service cable at a point between the main line and the premises being serviced. In such cases, there customarily is no excess cable for use in making the splice and it is necessary to splice in a short length of conductor between the severed ends of service conductor 28. The workman removes a portion of the insulation of each end of service cable 28 and cuts off an appropriate length of the extension 25 of each end cap and inserts one end cap over each of the conductor ends. One end cap is pushed backwardly along the conductor for a distance adequate to accommodate tube 12 which is'then threaded over the conductor. A short length of splice conductor 30 is prepared and its opposite ends are spliced to the cleaned ends of the service conductor 28. After these splices have been soldered, the parts of the encapsulating assembly are shifted toward one another until tube 12 is centered over the splice area. At this time, end caps 13 and 14 are snugly seated over the opposite ends of the tube which is now ready for the hermetic sealing operation.

The sealing operation is carried out with charging openings 16, 17, 18 facing upwardly and valve sleeves 26, 21 in open position. Usually, the end provided with charging openings 16, 17 is filled first. Valve 20 is rotated until in its fully open position with gap 22 registering with openings 16,17. A suitable potting compound 32, such as epoxy or any suitable high-dielectric, high-strength potting compound is charged into the shroud tube through openings 16, 17 care being taken not to fill the tube too rapidly to allow air to escape without risk of forming any trapped air bubbles. The assembly is easily checked for the presence of such bubbles owing to the transparent material used for tube 12 and valve sleeves 20, 21. It is preferably to overcharge the assembly leaving a small amount of surplus epoxy filling gap 22 of the split sleeve valves 20, 21 thereby assuring that no voids have been left -uncharged. This having been accomplished, the sleeves are rotated wiping away the surplus across the opposite edges of the charging slot and assuring that the potting material will be in contact with and bond to the interior surfaces of the sleeve valves bridging the charging openings. The potting compound, upon taking a set, forms a strong bond with the contacting surfaces of the end caps, tube 12, and any portions of the sleeve valves in contact with the compound. This adhesive bond, in cooperation with the housing proper, provides a permanent hermetically sealed enclosure for the splice with all parts firmly and permanently locked together in a fluid-tight condition.

Referring now to FIG. 5, there is shown a modified embodiment of the splice shroud assembly, designated 10, having the same general features described above in connection with FIGS. 1 to 4. The same or similar parts are designated'by the same reference characters distinguished by the addition of a prime. The principal difference resides in the fact that the shorter encapsulating assembly has but a single valved opening 16' and a modified end cap 14. Thus, in one of the end caps of the FIG. 5 construction, tubular extensions 25' project inwardly towards the center of tube 12 rather than outwardly, as they do in FIGS. 1 and 2. This has the decided advantage that the interior of the extension serves as a pilot to guide the conductor into and through its snug fitting smaller end. Additionally, the extension is embedded in and protected by the potting compound and includes a narrow annular space surrounding the conductor serving to provide stress relief for the conductor.

The FIG. 5 embodiment has but a single valved charging slot in view of the small size of the assembly. This valve is constructed similarly to that described above in connection with FIG. 2. This figure also shows a common mode of employing the splice where there is sufficient conductor material to splice the conductor ends to one another. This permits the assembly to be supported vertically with the conductors entering the lower end and the sealed end uppermost, as shown in FIG. 5 and providing even greater assurance against possible leakage of moisture into the interior.

In the case of the FIG. 5 assembly, the conductors are prepared and then inserted through the severed ends of extension 25. In this connection, it will be understood that the user may employ either the type of extension shown on end cap 13 or the intumed type shown on end cap 14. After the splice has been completed and soldered, the user assembles the tube 12' and end cap 14'. downwardly into end cap 13' and then employs the sleeve valve 20', as previously described, in charging the assembly with compound 32 and completing the hermetic sealing operation.

Referring to FIGS. 6-8, there is shown a further embodiment of the invention splice encapsulating assembly, designated generally "and wherein the same or similar components are designated by the same reference characters as in FIGS. 1-5, but distinguished therefrom by the addition of a double prime. This assembly differs essentially from that described above in that it encloses the splice between a pair of

cables

35, 36 each enclosing a plurality of pairs of insulated conductors embraced by a common shroud of electrical shielding, such as

metal foil

37, 38 and a

conventional sheath

39, 40. The two shielding

layers

37, 38 are held in firm electricalcontact with one another by a split bolt metal connector having unique features to be described in detail below.

The invention non-wrenchable split bolt connector comprises a split bolt 42 and a radially narrow ring nut 43. The threaded shank 42 is provided with a deep but narrow slot 44 having a width snugly receiving the

electrical shields

37, 38 of

cables

35, 36 after a short length of

sheath

39 and 40 has been removed from each of the cables. The inner end of slot 44 is semi-cylindrical and seats directly against the similarly contoured surface of the electrical shields. The exterior of shank 42 is provided with threads 46 mating with the threads of ring nut 43. The exterior of this nut is circular but roughened as by shallow axial grooves 48.

The closed end of split bolt 42 is provided with an annular flange 49 and this likewise may be roughened by axial grooves similar to grooves 48 on the nut ring. These grooves enablethe operator to obtain a firm finger grip with both the nut and the flanged end of the split bolt while grasping these components between the thumb and forefinger to tighten the parts. Since both the nut ring and the endof the split bolt are circular they cannot be engaged by a wrench and tightened excessively and so as to cause damage to the thin foil shielding 37, 38. Overtightening is very difficult to avoid if a wrench is used owing 'to the thinness and low strength of the shielding foil or braid.

As shown in FIGS. 7 and 8, the non-wrenchable connector can also be employed to secure a grounding wire 50 to the shielding layers 37, 38. This grounding wire desirably includes a plurality of annealed wires twisted together and are inserted against one of the shielding layers, as 37, in an area underlying the inner face end of nut ring 43. Tightening of the parts then compresses the shielding layers compactly together and in firm contact with the wires of grounding conductor 50. A surprising amount of pressure is applied between the contacting metal surfaces of the foil connector parts and the grounding wire using only finger strength to tighten the connector.

The splice assembly described above is prepared by removing an appropriate length of a nipple 24" on each end cap and inserting the shielded

conductors

35, 36 therethrough. One of the end caps is detached from tube 12 during the assembly operation to provide adequate room for completing the splice connections and securing the split bolt connector in place about the cable shields. FIG. 7 shows a pair of conductors from each of the cables exposed and spliced together in any conventional manner. The other pair of conductors may be similarly spaced together or may be retained in reserve for future use if needed and left embedded in the potting compound.

The foregoing assembly operations having been completed, the detached one of the end caps is reassembled over the end of tube 12" and the spliced junctions are centered in the splice housing and generally in axial alignment with one another as shown in FIG. 7. Thereafter the interior of the housing assembly is charged with potting compound 32" in the same'manner described in connection with FIGS. 1-5 and while opening 22" of sleeve valve 21" is in registry with charging opening 18". Thereafter the sleeve is rotated out of registry with opening 18" and compound 32 is allowed to take a set. Not only are all interior parts and surfaces strongly bonded to the potting compound, but the two

parts

42, 43 of the connector assembly are locked immovably together as tightened by finger pressure. Accordingly and owing to the potting compound, it is impossible for these parts to become loose in any degree despite severe temperature changes, shock, severe vibration or other adverse conditions.

Referring to FIG. 9, there is shown a second preferred embodiment of the non-wrenchable electrical connector. In this embodiment only the split bolt proper 42' is illustrated, it being-understood that the ring nut usable with this shank may be identical with that illustrated at 43 in FIGS. 7 and 8. Threaded shank 42' differs in that in lieu'of the roughened annular head portion 49 the closed end of the shank is formed with a generally semi-circular smooth surface 54. The shank is formed of ductile metal of good electrical conductivity and head portion 54 isprovided with an opening 55 sized to snugly receive a grounding wire such as wire 50. This wire may be locked in assembled position by using a prick punch or other suitable tool to upset the rim edge of opening 55 after the ground wire has been inserted therein.

The FIG. 9 connector is particularly suited for use in smaller sizes, it being found that a large roughened head such as that shown at 49 in FIG. 8 may be dispensed with since the user can grasp the opposite lateral sides of the overlapped ends of the cable in one hand while grasping the nut ring between the thumb and forefinger of his other hand while performing the tightening operation.

A third embodiment of thesplit bolt connector is illustrated in FIG. 10 and differs from that just described primarily in the provision of a threaded stud 58 projecting from the center of the rounded end portion 54'. A clamping nut 59 is threaded over shank 58 and used to clamp a grounding wire to the split bolt. This nut, along with a thumb nut corresponding to nut 43, are held tightened in the assembled condition of the connector be embedding the same in potting compound held in place about the connector in any suitable manner.

it will be understood that the invention connector may be used in a wide variety of operating environments other than those described hereinabove. The connector need not be embedded in potting compound in applications not subject to wide temperature changes, shock or vibration or other conditions likely to cause loosening of the parts. It will also be understood that the threaded stud 58 in FIG. 10 may be replaced by a threaded bore formed in the rounded end portion 54' of the connector shank. In this case, a short threaded screw may be used to hold the grounding wire clamped to the end of the split bolt.

While the particular encapsulating assembly for conductor junctions herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the detail of construction or design herein shown other than as defined in the appended claims.

We claim:

1 In combination, a plurality of shielded cables each having a plurality of insulated conductors enclosed by a metallic foil-like shield and an outer protective sheath, a short length of said protective sheath being removed from each of said cables to expose said spliced conductors and a ringlet of said foillike shield, the main bodies of saidcables being overlapped and firmly clamped together in areas spaced 'from their adjacent ends with said exposed shield ringthe semicylindrical inner end of said slot and sized to have a snug fit with the exterior surfaces of said shield ringlets, said shield ringlets being overlapped and assembled one on the other crosswise of said slot with the inner cable ringlet seated on the semicylindrical portion of said slot, and an open ended nut ring threaded from end to end thereof and free of wrench engaging surfaces assembled to said bolt threads and tightened solely by finger pressure to hold said overlapped shield ringlets firmly and immovably clamped against one another and the juxtaposed surfaces of said split bolt and said nut ring to provide a strong cable to cable connection and a high capacity electrical bond connection between said shield ringlets without risk of damage to said shield ringlets and to said conductors, and said split bolt connector providing for the direct transfer of tensile loads between the main bodies of said shielded cables without risking strain on the splice connections between conductors of said cables.

2. The combination defined in claim 1 characterized iFthItth exterior of the closed en'a'ar saidthr eaded bolt is generally semi-spherical in contour and has substantially the same diameter as the threaded portion thereof.

3. The combination definedin claim 1 characterized in iha t t lie exterior of the closed end bf 55m 815m bolt is formed with a small diameter bore, a grounding wire and in good electrical contact with said connector.

Claims

1. In combination, a plurality of shielded cables each having a plurality of insulated conductors spliced together and enclosed by a metallic foil-like shield and an outer protective sheath, a short length of said protective sheath being removed from each of said cables to expose said spliced conductors and a ringlet of said foil-like shield, the main bodies of said cables being overlapped and firmly clamped together in areas spaced from their adjacent ends with said exposed shield ringlets in direct contact by a non-wrenchable split bolt electrical connector to provide a reliable high-strength mechanical clamp and high-capacity electrical bond between said cable shields without risk of damage to said shield and the insulated conductors enclosed thereby, said split bolt connector consisting of a Threaded bolt having a deep slot extending axially thereof and opening through the threaded end of said bolt, said slot having flat parallel smooth sidewalls merging with the semicylindrical inner end of said slot and sized to have a snug fit with the exterior surfaces of said shield ringlets, said shield ringlets being overlapped and assembled one on the other crosswise of said slot with the inner cable ringlet seated on the semicylindrical portion of said slot, and an open ended nut ring threaded from end to end thereof and free of wrench engaging surfaces assembled to said bolt threads and tightened solely by finger pressure to hold said overlapped shield ringlets firmly and immovably clamped against one another and the juxtaposed surfaces of said split bolt and said nut ring to provide a strong cable to cable connection and a high capacity electrical bond connection between said shield ringlets without risk of damage to said shield ringlets and to said conductors, and said split bolt connector providing for the direct transfer of tensile loads between the main bodies of said shielded cables without risking strain on the splice connections between conductors of said cables.

2. The combination defined in claim 1 characterized in that the non-slotted exterior end of said threaded shank is generally semi-spherical in contour and has substantially the same diameter as the threaded portion thereof.

3. The combination defined in claim 1 characterized in that the non-slotted exterior end of said split bolt is formed with a small diameter bore sized to have a snug fit with the end of a grounding wire inserted axially into said bore, and the material of said split bolt being ductile and deformed against the grounding wire thereby anchoring the same in assembled position in said bore and in good electrical contact with said connector.