Patent Publication Number: US-4839473-A

Title: Waterproof electrical splice enclosure

Description:
FIELD OF THE INVENTION 
     The present invention relates to a waterproof electrical splice enclosures for an electrical connector connecting the ends of a plurality of insulated electrical conductors. 
     BACKGROUND OF THE INVENTION 
     At locations where insulated electrical conductors are to be electrically connected together, the insulation must be cut through, thereby disrupting the waterproofing provided by the insulation. One common method of connecting the conductors is to strip back the insulation from the ends of the conductors and to electrically connect the bared conductors together in a twist-on electrical connector. If the electrical connection is to be used in a location where it is exposed to water, for example by being buried in the ground, waterproofing must be provided around the connection. Many different types of waterproof electrical splice enclosures of varying complexity have been developed for this purpose as disclosed in U.S. Pats. Nos. 2,906,810; 3,523,607; 3,585,275; 3,934,076; 3,597,528; 4,039,742; 4,053,704; and 4,070,543. 
     SUMMARY OF THE INVENTION 
     The present invention provides a waterproof electrical splice enclosure for receiving an electrical connector connecting the ends of a plurality of insulated electrical conductors extending out of the connector in the same direction and parallel to one another. The enclosure comprises an elongate hollow tube having one open end and one closed end, the cross-sectional dimensions of the hollow space within the tube in a plane perpendicular to its length being slightly greater than the cross-sectional dimensions of the electrical connector in a plane perpendicular to the length of the insulated electrical conductors extending out of the connector. Means are provided for retaining the electrical connector at a connector retention position adjacent the closed end of the tube with the insulated electrical conductors extending from the connector out of the open end of the tube. A waterproofing fluid is within the tube, the waterproofing fluid under normal conditions of use having a sufficient viscosity so that it will not flow out of the tube, but being capable of flowing around the connector as it is slid into the tube to the connector retention position adjacent the closed end of the tube to fill the space around the connector and around and between the insulated conductors extending out of the tube to provide a waterproof seal around the connector and the connected ends of the insulated conductors. 
    
    
     THE DRAWING 
     In the drawing: 
     FIG. 1 is an elevation view of a waterproof electrical splice enclosure constructed in accordance with the present invention sectioned longitudinally approximately midway of its diameter to illustrate the interior of the enclosure; 
     FIG. 2 is a top view of the splice enclosure of FIG. 1; 
     FIG. 3 is a cross-sectional view along line 3--3 of FIG. 1; 
     FIG. 4 is a partially sectioned side elevation view of the enclosure with an electrical connector splicing a pair of insulated electrical conductor in position to be inserted into the splice enclosure; 
     FIG. 5 is a view similar to that of FIG. 4 with the electrical connector inserted fully into the splice enclosure; 
     FIG. 6 is a view similar to that of FIG. 5 with the cap of the enclosure closed; 
     FIG. 7 is a front elevation view partially in section with the connector and wires inserted into the enclosure as in FIG. 6; and 
     FIG. 8 is a front elevation view like that of FIG. 7 without any sectioning of the splice enclosure. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The waterproof electrical splice enclosure of the present invention is constructed for receiving an electrical connector 10 connecting the ends of a plurality of insulated electrical conductors 11 extending out of the connector in the same direction and parallel to one another. The illustrated electrical connector 10 is of the type that has an insulated outer shell within which is a metal connector that threads onto the bared ends of the electrical conductors to electrically connect them together. 
     The splice enclosure includes an elongate hollow tube 12 having one open end and one closed end, three connector retaining fingers 14 for retaining the electrical connector at a connector retention position adjacent the closed end of the tube 12, and a waterproofing fluid 16 within the tube. The splice enclosure, with the exception of the waterproofing fluid 16, is a one-piece plastic molding which includes a cap 18 for closing the open end of the tube 12. The preferred plastic is polypropylene. The closed end of the tube is molded in an open condition and is closed by ultrasonic welding. 
     The cross-sectional dimensions of the hollow space within the tube 12 in a plane perpendicular to its length are slightly greater than the cross-sectional dimensions of the electrical connector 10 in a plane perpendicular to the length of the insulated conductors 11 extending out of the connector. The dimensions are large enough to permit the connector and wires to be slid down into the tube but small enough to cause the connector and insulated conductors to displace a substantial proportion of the waterproofing fluid 16 to force the waterproofing fluid 16 to flow around the connector 10 and insulated conductors and fill the space around the connector and around and between the insulated electrical conductors 11. In the illustrated embodiment the tube 12 is cylindrical to accommodate the generally cylindrical connector 10. Six longitudinal ribs 20 are formed on the interior wall of the tube 12 and are spaced equally around the tube to center the connector 10 as it is slid into the tube 12 to aid in causing the waterproofing fluid 16 to flow around the entire connector as it is slid into the tube. 
     The three connector retaining fingers 14 are equally spaced around the tube and extend from the interior wall of the tube 12 into the hollow space within the tube. The connector retainig fingers are spaced from the closed end of the tube a distance slightly greater than the length of the connector 10 parallel to the insulated electrical conductors 11 to permit the electrical connector to be slid down the tube 12 past the fingers 14, the fingers being formed to be resiliently depressed by the connector and to resiliently spring back after the connector is slid past them and retain the connector in the closed end of the tube. To aid in accomplishing this, the connector retaining fingers 14 are inclined to the wall of the tube 12 converging toward the closed end of the tube. 
     The open end of the tube 12 is formed with a broadened entrance area 22 which has two opposed insulated conductro receiving channels 24 converging into the open end of the tube 12. 
     The cap 18 is connected to the tube 12 by a hinge area 26 permitting the cap to be pivoted to the closed position closing the open end of the tube 12 as illustrated in FIGS. 6 through 8. The cap 18 is formed with a latching projection 27 and a complementary latching shoulder 28 is formed on the opposite edge of the broadened entrance area 22 to latch the cap in its closed position. The cap 18 is also formed with a bulbous protrusion 30 to fit into and generally fill the open end of the tube 12. The bulbous protrusion 30 is deformable by the insulated conductors 11, as illustrated in FIG. 7, to firmly press the insulated conductors 11 into the insulated conductor receiving channels 24, thereby to strain relieve the connection. 
     The waterproofing fluid 16 under normal conditions of use has a sufficient viscosity so that it will not flow out of the tube 12 but at the same time being capable of flowing around the connector 10 as it is slid into the tube to the connector retention position adjacent the closed end of the tube to fill the space around the connector and around and between the insulated conductors 11 extending out of the connector to provide a waterproof seal around the connector and the connected ends of the insulated conductors. As used herein, &#34;normal conditions of use&#34; is intended to mean the environmental conditions and the state of the waterproofing fluid at the time the electrical connector 10 containing the ends of the insulated electrical conductors 11 spliced therein is to be inserted into the splice enclosure. The presently preferred waterproofing fluid is an azlactone gel formed by crosslinking an azlactone compound with a crosslinking agent, preferably a polyol, polythiol or polyamine and palsticizing the reaction product with an organic plasticizer material which is essentially inert to the azlactone/crosslinking agent reaction and which has the ability to become and remain blended with the reaction product of the azlactone compound and the crosslinking agent; specifically the azlactone gel disclosed in example 1 of U.S. patent application Ser. No. 910,528, filed concurrently herewith. 
     If the insulated conductors 11 are sufficiently stiff to permit the worker to grasp them at a point spaced from the electrical connector 10 and push on them to slide the connector into and down the tube 12 into the waterproofing fluid, as illustrated in the drawings, the forcible engagement of the insulated conductors between the bulbous protrusion 30 and the insulated conductor receiving channels 24 provides means for retaining the connector in the connector retention position adjacent the closed end of the tube. However, it is desirable to also have the connector retaining fingers 14 because they positively prevent the connector 10 from being pulled back after it is fully inserted into the tube and before the cap is closed, since with some waterproofing fluids pulling back of the connector may open a path through the waterproofing fluid to the connector. If the insulated conductors are not sufficiently stiff to push with, a separate connector pusher may be provided and it may remain in the tube 12 and comprise the means for retaining the connector adjacent the closed end of the tube.