US2004592A - Electrical conductor cable - Google Patents

Description

June 11, 1935. J, ALDEN 2,004,592

ELECTRICAL CONDUCTOR CABLE Filed May 12, 1955 INVENTOR J. L. ALDEN ATTORNEY I -Patented June 11, 1935 2,004,592

UNITED STATES .PATENT OFFICE 2,004,592 ELECTRICAL CONDUCTOR CABLE John L. Alden, La Grange, Ill., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation oi New York Application May 12, 1933, Serial No. 670,698

2 Claims. (01. 173-264) This invention relates to electrical conductor in order to afford the highest degree of both cables and more particularly to multiconductor mechanical flexibility and flexure endurance and cables intended for uses in which the cables are of electrical conductivity. subjected to repeated flexure. A plurality of such conductor strands ll each 5 A principal object of the invention is to procomprising as described a central non-conduct- 5 vide a cable of the character described which ing core and two or more conducting ribbons is of high conductivity and at the same time of wound thereon in an open helix, is then comgreat endurance under repeated flexure. bined to form the core of a principal conductor With this and other. objects in view, one emgenerally indicated by the numeral It, the numbodiment of the invention contemplates 0011- her of strands ll thus composing a principal l0 ductor Strands pv d f a p li y of ribconductor depending upon the relation between bolls of conductive a al Wound upon a centhe current carrying capacity of an individual tral non-conductive supporting strand, a bindstrand II and the purpose for which the coming and protective layer of textile strands bindpleted cable is intended. In one instance where 5 ing together the combined strands of the com the cable is intended for household heating apductors, a sheath of electrically insulating mapliances of comparatively heavy power conterial upon the textile binding of the conducsumption such as flat irons, hot plates, etc., tors, a sheath of heat insulating material there each' principal conductor comprises nineteen Over, a d an Outer yer of bi di g and p otec conductor strands. Although conductor strands 2 tive textile strands over all.

Other objects and characteristic features of of the advantages of the invention may be 0bthe invention Will pp from the following tained by using small round conductive wires tailed description of one embodiment of the'inarranged in the manner herein described. vention taken in connection with the -accom- Each assembly of conductor strands ll com- D y d a in w c bined into a principal conductor is provided with 25 1 represents a view of a piece f c a binding cover of textile threads i5 preferably ductor cable constructed in accordance with the wound on over the conductor, although in some invention and p ve y f ayed ut at One instances they may be braided together over the end to show the various elements combined in group of conductor strands instead of being the structure, and wound thereon. A layer of electrically insulat 30 Fig. 2 is an enlarged view of a piece of one of ing material It is deposited on the binding the Conductor Strands threads [5 in a seamless sheath as shown. This I In the embodiment herein disclosed the cable insulating material 16 is preferably a soft, tough comprises two conductor strands l0 and various and pliable compound of rubber or the like havprotective and uniting sheaths. Each of the ing a high degree of flexibility and electrical 35 two conductors I 0 consists of a plurality of ininsulating quality as n as composition tertwisted St a ds l I each having ce al no nocuous to the chemical composition of the undu t s supportin e 12 pr f ra ly f texdcrlying metal ribbons. Such compounds may tile thread spun from cotton or the like which be made with a rubber material as base which 40 has been previously thoroughly freed from delcontains substantially no free sulphur. Even 40 ,eterious or metal corrosive substances. So far so the interposed textile layer I5 is preferably as the conductor strands H are concerned, the made sufficiently dense to prevent any direct co es I! are c efly designed to P v de sile contact of the electrically insulating material It strength and to relieve the conducting elements with the metal ribbons.

themselves of tensile stress and at the same time Over the electrically insulating sheath I6 is 45 to afford minimum resistance to flexure. Upon applied a layer of thermally insulating material each of the cores I2 is wound the actual electri- IT. This may be a layer of strands spun from cally conducting element comprising two or more fibrous asbestos or analogous material wound tape-like fiat ribbons 13 of metal, preferably or otherwise applied over the sheath l6. Prefwound one on top of the other in an open nonerably the thermally insulating material is ap- 50 self contacting helix upon the core l2 as shown, plied in such a way as to be fluffy and porous although in some instances these ribbons may in texture so that the entrapped air will aid be laid upon the core l2 side by side or only in rendering the layer heat proof. partially overlapping. The ribbons l3 are pref- As herein disclosed two principal conductors erably of copper of utmost practicable purity l4 constructed as described are intertwisted in the form of flat ribbons are preferred, some and finally provided with an outer binding and protective covering of textile strands I8, preferably braided on, although in some instances it may be satisfactory to wind or spin the strands l8 in place. Evidently more than two principal conductors may be thus combined into a multiconductor cable if desired. Also in some cases it may be preferable to combine the principal conductors without twisting.

The various details of characterizing construction thus combined provide a cable of vastly improved flexibility and endurance. In one instance a cable constructed as described showed an average endurance of 44200 and a. maximum of 50861 cycles of fiexure before failure when tested by the Underwriters Laboratories. The standard requirement for such cables is 3000' cycles for cables intended for household'use with electric flatirons and one cable of customary construction now on the market has endured 12000 cycles.

The embodiment of the invention herein disclosed is illustrative merely and may be modified and departed from in many ways without departing from the spirit and scope of the invention as pointed out in and limited only by the appended claims.

What is claimed is:

1. In a conductor cable, a plurality of intertwisted principal conductors each comprising a plurality of conductor strands intertwisted without a core strand and each composed of a.

plurality of fiat ribbons of conductive material wound in an open helix upon a central nonconductive core, a. sheath of non-conductive binding strands upon each plurality of conductor strands, a sheath of electrically insulating material over each sheath of binding strands, a sheath of thermally insulating material over each sheath of electrically insulting material,

and an outer binding sheath of non conductive strands braided over the whole.

'2. In a conductor cable, a plurality of intertwisted principal conductors each comprising a plurality of conductor strands intertwisted without a core strand and each composed of two flat ribbons of copper wound in an open

Images