US2577049A - Shielded terminal having a composite metal ferrule for a flexible conduit - Google Patents

Description

w. A'. ULINE Dec 4, 1951 SHIELDED TERMINAL HAVING A COMPOSITE METAL FERRULE FOR A FLEXIBLE CONDUIT Filed June 25, 1945 INVENTOR.

ATTORNEY."

Patented Dec. 4, 1951 SHIELDED TERMINAL HAVING A COMPOS- ITE METAL FERRULE FOR A FLEXIBLE CONDUIT William A. Uline, Sidney, N. Y., assignor to Bendix Aviation Corporation, New York, N. Y., a

corporation of Delaware Application June 23, 1945, Serial No. 601,257

3 Claims.

This invention relates to radio shielding apparatus and more particularly to radio shielded conduits, or the like, adapted for use in shielding and protecting the conductors of an ignition system for an internal combustion engine.

An object of the present invention is to provide a novel metal enclosed, flexible conduit which has desirable physical characteristics and advantages that are not possessed by known constructions.

Another object of the present invention is to provide a novel radio shielding conduit which is so constructed that the use of expensive flexible metallic conduits heretofore employed to insure durability is completely eliminated.

Another object of the invention is to provide a radio shielding conduit of novel construction whereby the inner portion may be made of fleX- ible non-metallic material and yet will withstand the many stresses and strains occasioned by frequent or continuous bending and vibration.

A further object is to provide a radio shieldlng conduit which, by reason of the novel construction thereof, presents a smooth, unbroken interior surface to the cable or conductor enclosed thereby so that chafing of the insulation on the cable or conductor is reduced to a minimum or substantially eliminated.

A still further object is to provide novel coupllng means for mechanically and electrically connecting a radio shielding conduit or the like to the engine and other suitable electrically grounded component parts thereof.

Another object is to provide novel flexible conduit means which will exclude moisture and grease and which also adapts itself to the application of a braided metallic covering.

The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying drawing. It is to be expressly understood, however, that the drawing is for the purpose of illustration only, and is not intended to define the limits of the invention, reference for this latter purpose being had primarily to the appended claims.

In the drawing, the single figure illustrates a fragmentary portion of one form of radio shielding conduit constructed in accordance with the present invention, with portions thereof broken away and other portions in section for purposes of clearer illustration.

In the form shown, the novel conduit comprehended by the present invention, comprises a flexible solid cylindrical core or inner conduit 5 which may enclose, for example, a high tension ignition cable or conductor (not shown). Conduit or tube 5 is preferably molded from a suitable flexible rubber or rubber-like material, such as neoprene, and has a smooth unbroken internal surface or bore 6, as well as a smooth unbroken external surface or outer periphery l', extending throughout the entire length thereof. Natural rubber or other synthetic rubbers. particularly those which will retain their flexible properties at extreme high and low temperatures without cracking and which will resist the swelling and solvent action of oils and gasoline, may also be successfully used in making conduit 5. In the molding of conduit 5, an open wound coil spring 8 is embedded therein throughout the entire length thereof to serve as flexible reenforcing means for said conduit and to hold the latter against circumferential contraction and expansion. It will be understoodthat spring 8 may be embedded in conduit 5 by extruding said conduit over said spring. The smooth interior surface '6 of conduit 5 and the non-contracting feature of said conduit, eifected by spring 8, reduces to a minimum or substantially eliminates chafing of the ignition cable enclosed thereby. Spring 8 is preferably made of relatively stiff music wire, thereby imparting substantial lateral or transverse rigidity to the conduit while permitting the same to be bent sharply without danger of damage.

Conduit 5 is surrounded throughout its entire length with one or more, preferably two, layers 9 of braided or woven metallic strips or wires. In the illustrated embodiment, the layers or braids 9 are each formed of five .010 diameter bronze wires per pick, woven two over and two under so as to provide substantially per cent coverage. The reinforcing spring 8 provides radial support for the conduit 5 to permit satisfactory application of the woven metallic layers 9.

In order to lessen the amount of moisture, oils, and foreign materials, such as dirt particles, entering the woven layers or braids 9 when they are flexed by bending or vibration, and to increase the life of the conduit, the outer braid 9 is covered by a layer [0 of rubber-like material, such as neoprene. Natural rubber or other synthetic rubbers may be successfully used as the covering material, which is abrasive resistant and will retain its flexible properties at extremely low and high temperatures without cracking, and which will resist the swelling and solvent actions of oils and gasolines. The length of covering l0, although shown as being less than ,3 the length of conduit and braid 9, may extend over the end fittings or ferrules hereinafter described. The material of covering IIi may be loosely mounted or extruded on or vulcanized to the outer braid 9. the spaces between the strands in said braid and thus prevents entry of any foreign matter, thereby minimizing wear of the latter when the conduit is flexed by bending or vibration.

The shielding conduit comprising tube 5, braids 9, and covering Ill has secured to each end thereof ma novel manner,- novel coupling means for mechanically and electrically connecting said conduit to an associated part, such as a spark -".plug or ignition shielding harness manifold.

Since the coupling means is the same in construction and mounting at each end of the conduit, only one is shown and described. As shown,

In the latter forms it fills IS, a plurality of external axially spaced annular teeth 20 or the like, and a central bore I8 which is originally tapered or somewhat smaller than the diameter of bore 6. Sleeve I2 is later expanded to make bores Ii and I8 approximately equal. In assembling ferrule members II, I2 and nut I3 and mounting of the same on conduit 5, the nut I3 is first engaged over ferrule body II and the latter may then be slipped over the exposed end of conduit 5 and braids 9 until shoulder I5 in said body engages the extreme ends of said conduit and said braids, Thereupon ferrule core I2 is inserted in the bore 6 of conduit 5 through the open end of ferrule body II until shoulder I9 on said ferrule core engages the shoulder I5 on said ferrule body. A suitable mandrel is then inserted into sleeve II to expand the same to the illustrated diameter. External pressure is then applied in a. suitable manner around the sleeve I4 of ferrule body II, while the ferrule core I2 is suitably supported by said mandrel against collapsing, thereby squeeezing or compressing the sleeve portion IIl onto the outer braid 9 and causing the teeth 20 on ferrule core I2 to penetrate and become embedded in the yieldable conduit 5, as shown in the drawing. Thus, the coupling means will be firmly and permanently secured to conduit 5, and electrically connected with braids 9, and does not require soldering or the like to obtain a good electrical connection and to prevent displacement of said coupling means from said conduit. In attaching the shielding conduit to an engine or component part of a shielding system, the nut I3 is threaded onto a suitable fitting in a manner well understood in the art, and through engagement of said nut with the shoulder I! on ferrule body II, the shielding conduit is securely attached in position.

There is thus provided a novel conduit adapted for use in enclosing high tension ignition cables. which through the provision of a flexible reenforced non-metallic inner conduit is simple and inexpensive to manufacture and will withstand the many stresses and strains occasioned by frequent or continuous bending and vibration. Additionally, the non-metallic reenforcing inner conduit cannot contract, and provides a smooth unbroken interior surface, thereby reducing to a minimum or substantially eliminating all chafing of an insulated ignition cable enclosed therebyf There is also provided novel solderless coupling means for mechanically and electrically connecting a radio shielding conduit to an engine or other part.

While only one embodiment of ,the present invention has been illustrated and described in detail, it is to be expressly understood that the same is not limited to said embodiment. Various changes may be made in the materials suggested and in the design and arrangement of the parts illustrated without departing from the spirit and scope of the invention, as will now be clear to those skilled in the art. For example, the reenforcing coil spring 8 may also be employed as a conductor by connecting the same with the metallic braids or with the coupling ferrules. Additionally, said spring may be embedded in conduit 5 nearer the inner or outer surface thereof. Also, in the method of assembly the outer sleeve II may be soldered to braid 9. For a definition of the limits of the invention, reference is had primarily to the appended claims.

What is claimed is:

l. Atubular conduit comprising a flexible tube of yLeldable material, such as rubber or the like, a braided metallic covering closely surrounding said tube, and a composite metallic ferrule secured to the end of said tube, said ferrule comprising an outer tubular body having at one end thereof a thin-walled sleeve portion with a smooth internal wall surface surrounding the end of said tube and an internal shoulder at the inner end of said sleeve portion against which said tube abuts, and a tubular ferrule core slidably extending through the smallest internal diameter of said body, said core having an external flange at one end engaging an internal shoulder in said body facing oppositely to said first-named shoulder and a'liner portion having external ridges thereon extending into said tube, said liner portion being expanded in said tube to extend the end portion thereof and said sleeve portion being swedged inwardly to clamp the tube between said liner and sleeve portions, the latter being reduced in diameter gradually from both ends to a maximum at about the longitudinal center thereof.

2. The combination of a conduit and a composite metallic ferrule secured to the end of said conduit, said ferrule comprising a metallic liner extending intoan end portion of said conduit and having an internal diameter approximately equal to the internal diameter of said conduit, and a metallic body surrounding said liner and having a thin-walled sleeve portion surrounding said end portion of the conduit, said liner having teeth on the external surface thereof gripping said conduit and an external flange thereon engaging a shoulder in said body to limit movement thereof into said conduit, and said sleeve portion having a smooth inner surface engaging said tube and being arcuately flared from the longitudinal center thereof toward both ends, the inner diameter at said center being less than the normal outer diameter of said conduit, whereby said end portion of the conduit is securely clamped between said liner and sleeve portion.

3. The combination defined in claim 2 wherein said conduit comprises a tube of flexible material, such as rubber, and a braided wire covering closely surrounding said tube and directly engaged by said sleeve portion.

WILLIAM A. ULINE.

(References on following page) 5 REFERENCES CITED Number The following references are of record in the 2,241,125 file of this patent: UNITED STATES PATENTS 2,333,350, Number Name Date 2,393,496 182,723 Tyler et a1. Sept. 26, 1876 228,161 Adlam June 1, 1880 839,260 Benson Dec. 25, 1906 Number 2,006,828 Flynt July 2, 1935 10 146,941 2,228,018 Scholtes Jan. 7, 1941 538-654 Name Date Girard May 6, 1941 Wermine Mar. 24, 1942 Robertson June 23, 1942 Weatherhead, Jr. Nov. 2, 1943 Stedman Jan. 22, 1946 FOREIGN PATENTS Country Date Switzerland July 16, 1931 Germany Nov. 16, 1931

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