US 3622685 A
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Description (OCR text may contain errors)
United States Patent Inventor Robert R. Crowl R.D. #4, Box 48-13, Belle Vernon, Pa. 15012 Appl. No. 22,498
Filed Mar. 25, 1970 Patented Nov. 23, 1971 FLEXIBLE ELECTRIC CONNECTOR 2 Claims, 10 Drawing Figs.
US. Cl 174/84 C, 29/628, 174/90, 339/276 R Int. Cl "02g 15/08 Field of Search 174/84, 84 C, 84 S, 90, 94, 94 S; 339/276, 177, 262; 29/628 References Cited UNITED STATES PATENTS 1/1948 Frank 174/84 S 3,067,401 12/1962 Rhodes 174/84 S UX FOREIGN PATENTS 381,366 10/1932 Great Britain 174/84 R Primary Examiner-Darrell L. Clay Att0meyBuell, Blenko and Ziesenheim ABSTRACT: A connector for use in making a mechanical and an electrical connection between the ends of insulated cable. The connector has a flexible sleeve formed from a series of interwoven wires and a pair of collars attached to each end of the sleeve. The ends of the conductive elements to be spliced are passed into the collars and the collars are crimped about the conductive elements to form the connection.
FLEXIBLE ELECTRIC CONNECTOR This invention relates to a flexible connector; more particu larly, to a flexible connector which is useful in making both an electrical and a mechanical connection between the ends of an insulated conductor.
Portable electrical equipment has long been used in many phases of industry. In particular, the coal mining industry has for many years used mobile electrical tools and support equipment in underground mining operations. Use of such equipment requires that insulated electrical conductors or cable be trailed behind the equipment as work progresses in the mine. These "trailing cables" must be of sufficient durability to withstand abrasion on jagged rock and coal surfaces and yet be flexible enough to be wound upon a reel, passed over rollers or pulled around sharp comers. Usage of trailing cables under those conditions often leads to breaks in the conductive element of the cable or to outright severing of the cable itself.
The present practice in coal mines is to repair a broken cable by making what is called a temporary splice" in the cable. A temporary splice is made by stripping back the insulation on the ends to be joined, overlapping the conductive elements, crimping rings about the overlapped conductors and covering the splice with insulating tape. A splice made in this fashion is advantageous because it can be made quickly without special equipment and does not require a highly skilled worker. The disadvantage of a temporary splice is that present Federal regulations require that no more than flve temporary splices may be made in a trailing cable before the cable must be replaced. The temporarily spliced cable must then be repaired to make the splices permanent." This involves a process of reweaving and spot-welding the conductors, reinsulating, and finally vulcanizing the finishing splice; a process which causes considerable expense and inconvenience to the mining industry.
Materials and procedures for insulating and rejacketing spliced trailing cables at the job site have been available for some time, but the mining industry has found no suitable means for connecting the conductive elements of the cable in order to meet the demands on trailing cable detailed hereinabove. A permanent splice must be mechanically strong with adequate conductivity and flexibility. This means that the conductive elements must be joined in abutting or coaxial relationship. If a rigid sleeve-type connector is used, the area of the connection is too rigid to allow the cable to be passed around pulleys and wound onto reels. Thus, a cable so joined often fouls or catches, thereby hindering the orderly progression of mining operations. Also, a rigid connector tends to cause extraordinary stresses in the cable, often causing a splice to pull apart.
I provide a connector for use in making a mechanical and an electrical connection between the ends of insulated conductors comprising a flexible body member formed from multiple elements of electrically conductive material; and a pair of crimpable collars connected to the ends of said body member, said collar members being formed from electrically conductive material and adapted to be compressed about said conductors to make said connection. I preferably provide that said body member is a sleeve formed from interwoven bundles of wires, said sleeve being adapted to receive said ends of said conductors in coaxial relationship.
l further provide a connector for use in making a mechanical and an electrical connection between the ends of insulated conductors comprising a flexible sleeve member open at each end formed from a series of interwoven wires, said sleeve member being adapted to receive the ends of said conductors to be joined and to embrace said conductors so as to maintain them in coaxial relationship; and a pair of collar members formed from an electrically conductive material coaxially connected to each end of said sleeve member, said collar members being adapted to be compressed about the conductors passing therethrough.
Other details, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof proceeds.
In the accompanying drawings 1 have shown certain present preferredembodiments of the invention in which:
FIG. 1 is a form ready for use;
FIG. 2 is a longitudinal view, taken partly in section and partly in elevation, of my invention showing the manner in which it is used to join the ends of electrical conductors;
FIGS 3 through 5 are enlarged fragmentary longitudinal sectional views of one end of the connector of FIG. 1 illustrating various methods for assembling the parts of the connector;
FIGS. 6 through 9 are prospective views showing, in stepwise fashion, a method of joining the ends of electrical conductor; and
FIG. 10 is a longitudinal view, taken partly in section and partly in elevation, of the ends of electrical conductors showing means for preventing abrasion of the invention when placed thereon.
Referring to the drawings and particularly to FIG. 1, the connector of the present invention, generally designated by the numeral 1, includes a sleeve 2. Sleeve 2 is formed from a flexible electrically conductive material and is preferably tubular. The cross-sectional configuration of sleeve 2 usually conforms to that of the conductive elements of the cables to be joined; in the drawings that configuration is shown to be generally circular. One type of material which may be used to form sleeve 2 is a braided or interwoven series of bundled copper wires. The primary considerations in selecting a suitable material to form the sleeve 2 are that the sleeve 2 must be flexible, electrically conductive and possess good tensile strength.
Hollow collars (or lugs) 4 are attached to each end of sleeve 2. Collars 4 are formed from an electrically conductive metal such as copper or a copper alloy and preferably have a crosssectional configuration similar to that of sleeve 2. The attachment of the collars 4 to sleeve 2 may be accomplished by fusion, brazing or other means well-known to persons skilled in the art.
FIGS. 3-5 show three possible embodiments of a collar 4, any of which may It: used to assure good mechanical and electrical connection between the collar 4 and the sleeve 2. However, these embodiments are not intended to limit the invention as persons skilled in the art may devise other configurations for the collars 4 to facilitate attachment of the sleeve 2.
Referring to FIG. 3, it may be observed that the collar 4a is provided with a reduced cross-sectional portion, the outer surface region of which is designated by the numeral 6. The inner surface of an end of sleeve 2 rests upon surface 6. The advantage to this embodiment is that after sleeve 2 is attached to collar 40, the combined collar and sleeve present a uniform or nearly uniform cross section. This facilitates the application of insulation and the cable jacket because there are no surface irregularities on the connector which might cause corresponding surface irregularities on the finished splice.
FIG. 4 shows a collar 4b of uniform cross section having the inner surface of sleeve 2 drawn over a major portion of its external surface. The advantage to this configuration is that a large area of contact is provided between collar 4a and sleeve 2, thereby enhancing the bond between the two. FIG. 5 shows essentially the reverse of FIG. 4 in that the sleeve 2 is drawn inside thecollar 40 so that the outer surface of sleeve 2 is in contact with the inner surface of collar 4c. An advantage of this configuration is that when collar 40 is compressed or crimpedabout the conductor (not shown), that portion of sleeve 2 which is within collar 40 is pressed into tight engagement with the conductor. This arrangement serves to reduce the possibility of the sleeve 2 tearing away from collar 40 when tension is applied to the splice.
Having described the structure of the present invention, I now turn to a description of how the invention is used to make a splice between the ends of two conductors or cables. Referring first to FIG. 6, what is shown there are the ends 8a and 8b of the conductive portions [0a and 10b of two cables, generally designated 12a and 12b respectively. Generally, a
prospective view of my invention in assembled cable such as cable 120 consists of a conductive portion a surrounded by an insulating sheathing 14. Sheathing 14 may be rubber, plastic or some other pliable material having insulating qualities. Conductive portion 100 may be a single wire or a bundle ofwires 16 as shown in FIG. 6.
Before joining cables 12a and 12b with the connector of the present invention, it is first necessary to strip back the sheathing 14 from the conductive portions 100 and 10b to a point where the sum of the lengths of exposed conductive portions 10a and 10b exceeds the overall length of the connector 1. The exposed conductive portions 10a and 10b should then be cleaned by techniques well-known in the art to assure good electrical continuity after the splice is made.
Next the connector I is brought into coaxial alignment with a first conductive portion, say 10a, and the end 8a thereof inserted into collar 4 and beyond to a point in sleeve 2. It may be noted here that the desired relationship between ends 8a and 8b of conductive portions 10a and 10b, respectively, and the parts of connector 1 in a finished splice is shown in FIG. 2. A high compression crimping tool or other suitable apparatus is applied to collar 4 to tightly compress collar 4 about conductive portion 10a. This crimping operation establishes a firm mechanical connection and a good electrical connection between collar 4 and conductive portion 10a. The same procedure is then followed in crimping the other collar 4 about conductive portion 10b after passing end 8b through the other collar 4 and into sleeve 2. The completed joinder of conductive portions 10a and 10b is shown in FIG. 7.
In FIG. 10, I have shown means for capping the ends 8a and 8b to prevent abrasion of sleeve 2 by any sharp edges on those ends as the splice flexes. The caps 18 are generally hemispherical in shape and made from any suitable conductive metal. If desired, the capped ends 8a and 8b may be brought into abutment as shown in FIG. 10.
It may also be observed that the use of braided or interwoven material to form sleeve 2 serves to bring Kellems Principle into play to prevent conductive portions 10a and 10b from pulling apart. That is, the greater the tension applied to conductive portions 10a and 10b tending to pull them apart, the greater the compressive force applied by braided sleeve 2.
The final steps in making a splice embodying the present invention are the application of insulation to the exposed connector and rejacketing the cable. FIGS. 8 and 9 are illustrative of these procedures but are by no means limiting since a variety of well-known methods may be used. As shown in FIG. 8, insulating tape 20 may be wound in spiral fashion about the connecter l and exposed conductive portions 10a and [0b. This may be followed by the application of a suitable sheathing material 22 as shown in FIG. 9. Well-known procedures may be employed to seal the splice so as to exclude moisture.
1. A splice between a pair of electrical wires brought together in generally coaxial relationship comprising:
A. a pair of metal caps having a generally hemispherical shape fitted upon the ends of said wires;
B. a sleeve formed from bundles of interwoven wires surrounding said wires; and
C. a pair of hollow collars attached to the ends of said sleeve and crimped about said wires.
2. A splice between a pair of electrical conductors brought together in generally coaxial relationship comprising:
a flexible sleeve formed from a series of interwoven wires surrounding said conductors; and
a pair of hollow collars attached to the ends of said sleeve and crimped about said conductors.