US2126002A - Cable bonding means - Google Patents

Description

Aug. 9, 1938.

F. GQGARDNER' CABLE BONDINGHMEANS Filed March 12,- 1936 INVENTOR fiPAW/r 6. GHAPUNEI? ATTORNEY zzgm 4 The. invention consists of the Patented Aug. 9, 1938 "PATENT OFFICE oannn noNnnvG mums Frank G. Gardner, Maplewood, 1v. 1., assignor I to Breeze Corporations, Inc, Newark. N. I.

Application March 12,1930, Serial no. 68,418

9 Claims. (Cl. 241-4) This invention relates to a cable bonding means. Where radio equipment isused in proximity to ignition or other electrical circuits it is necessary to shield and ground the circuits to prevent 5 interference with the radio equipment. To

achieve efilcient shielding it is necessary to properly bond the various parts of the shield to one another and to ground. Unless the parts are properly bonded noises will be set up in the radio equipment which will seriously interfere with its operation. Furthermore, a fire hazard is presented where shields surrounding electrical .circuits have loose connections because of the danger of electrical flashes. Therefore, the

is broad object of this invention is to provide means to effectively bond together the parts of a radio shielding system.

In connecting parts of a shielding system to gether it is common practice to provide a terminal or stufling box to receive a shielded conductor.

Theterminal member is larger than the shielded conductor and packing is applied around the conductor and held in place by a packing nut. The opening through the terminal member and the packing nut is larger than the shielded conductor to permit ease of installation. This provides a relatively liquid-proof joint, which is desirable and necessary, but does not provide a good electrical bond between the parts. In such a construction'the electrical contact between the parts is only casual or intermittent. Therefore. the specific object of this invention is to provide a bonding means which may be applied between cables and terminal members to whichthe cables inay be connected.

A further object of the invention is to provide a simple, inexpensive means for bonding which may be applied to cables of any size, and which may readily be usedwith new or existing installations without any modification of the existing parts.

A further object of the invention is to provide 7 a continuous strip from which a .section may be cut or broken so that such section may be applied to a particular size of cable.

construction.

combination and arrangement .0! parts, as herein illustrated, described and claimed.

In the accompanying drawing, forming part hereof, are illustrated various embodiments 0! the invehtiongin which drawing similar reference characters designate corresponding parts,

and in which reference letters designate parts old in the art and reference numerals designate the actual invention herein, and in which:

11 Figure 1 is a vertical section through a terminal boir, the bonding means being partly broken Figure 2 is a horizontal section, taken approximately on line 2-2 oi Figure 1, looking downward;

Figure 3 is an enlarged detail in perspective, 5 of one form of bonding means;

Figure 4 is a detail in perspective of one form oibonding means;

Figure 5 is a vertical section, similar to Figure 10 l, but showing the application of a. modified form V 01 bonding means Figure 6 is a horizontal section, taken approximzrtgly on line 8-6 of Figure 5, looking downw r Figure 'l is a plan view oi another modification 15 of bonding means; and,

l 'igureiiisaverticalsectiomsimilartoFigure 1, showing the application of a still turther modification of the invention. 20

Referring to the drawing, A designates a terminal or stufling box into which a cable is introduced. The member A may be a Junction box or any device to which an electrical cable might be connected. The inner end of the member A is 25 provided with a bore B so that the cable may pass therethrough. Adjacent the bore B the member A is provided with an annular inclined laceCtoreeeiveapacklngashereinafterda scribed. Disposedthrough the member A ha 30 cable comprising one or more conductors D, insulation E and shielding F. The shielding F may be aleadeovering oi ordinary form or may consist of a shielding condulthaving an outer coveringotbraidedwireG. Thecablemayberleld,

semi-rigid or flexible.

around the shielding F in the terminal A. is packing H which'is usuallyeither a nonconductor or a very poor conductor. Above the "packingi-IisdisposedawasherJhavingataperfi' 40 art and are presently in use. 'lhepresent inu vention is designed to overcome the dlficulties presented with the foregoing construction.

Referring to Figures 1. to 4, 9 designates a wire which may be triangular in cross-section. The base of the wire 9 is applied against the shielding F, while one side of the triangle contacts the packing nut L and the opposite side contacts the washer J. The wire 9 is provided with a series of notches it, which permit the bending of the wire 9 around the shielding F and permit any desired length of wire 9 to be readily broken off from a roll or other quantity of wire 9.

The notches it may be formed by cutting portions from the apex of the triangular wire t, or

the notches it may be formed by simply displacing some of themetal without actual removal. The base of the triangular wire 9 is provided with a straight knurl H, as shown in Figure 3, so as to provide arough surface to bite into the shielding F to make a good electrical contact. In some cases the shielding F will be covered with a lacquer, varnish or other nonconductor, and the roughened portions provided by the knurl it will break through such covering to establish an electrical bond.

When it is desired to apply the wire 9, the

packing nut L is unscrewed to give access to the interior of the terminal A. A piece of wire 9, of suflicient length to surround the shielding F, is broken off from the main body of wire 8 at the nearest notch iii; The wire 9 is then bent around the shielding F, with the notches it out-- ward, the notches it reducing the resistance of the wire 9 to permit bending. The packing nut L is replaced and tightened. One edge of the wire 9 will enter the bore M between the shielding F and the nut L. The opposite edge of the wire 8 will enter the corresponding opening in the washer J. Since the bottom edge of the nut L rides against the tapered face of the wire 9, the nut L will force the wire 9 securely against the shielding F and a good electrical bond will be achieved. In addition, the cable will be held rigidly in position to prevent casual removal. To this extent the bonding means also acts as a locking means, since previously only the pressure of the packing H restrained the casual movement of the cable in the terminal A.

In Figure 4 is shown a'section of wire 9 without notches ill. Where the diameter of the cable to be bonded is sufliciently small to permit the use of a small wire 9,'it is sometimes feasible to use a triangular wire 9 without any notches iii.

If the wire 9 is sumciently small in cross-section and of such character as to be readily bent around the shielding F, the notches ID are not necessary. However, where a relatively large wire 9 is used the notches it are necessary to permit either bending or breaking 01? of. the wire 9 at any desired point.

In Figure '5 is shown a modified form of bonding means in which there is provided a continuous strip having reduced portions M to facilitate bending or breaking off of a given length. Intermediate of the portions I? the strip is provided with curved'projecting surfaces l3. This form of bond may be cut from a single flat strip, the

portions i3 being formed by rolling or other'sultable means. The application of this form is the same as the triangular wire 9. The edges of. the

' parts I3 will enter the space between the shielding F and the nut L: As thenut L is tightened a permanent electric bond will be made between the parts.

In Figure 7 is illustrated a further modification Instead of a wire or strip there is provided a split tapered wedge l5 provided with an annular flange it. The upper portion of the wedge it enters the space between the shielding F and the packing nut L. As the nut L is tightened the flange it forces the washer J to compress the packing H and at the same time the split wedge i5 is constricted around the shielding F and makes a good electrical bond between the shielding F and the nut L.

From the foregoing it will be seen that a good electrical bond is provided with all forms of the invention. The various forms may be readily applied to any installation using a stumng or junction box of the type described. It will be obvious that a good electrical connection exists cross-section, said wire being bendable and having one apex thereof formed with reduced portions to facilitate the bending of the wire.

2. As a new article of commerce a metal bonding wire of triangular cross-section, one apex of the triangle being formed with notches to facilitate the severance of a section of wire from the main body thereof and to facilitate the bending of said wire, the base of the triangle opposite the notched apex being knurled.

3. A device to make an electrical bond between a metal covered cable and a terminal which receives the cable comprising a strip having weakened portions to facilitate bending of the strip, said strip being bent around a cable and having a terminal contact face extending outwardly from the cable.

4. A device to make an electrical bond between a metal covered cable and a terminal which receives the cable comprising a strip of substantially triangular cross-section having weakened portions to facilitate bending of the strip, said strip being bent around a cable and having a terminal contact face extending outwardly from the cable.

5. A device to make an electrical bond between a metal covered cable and a terminal which receives the cable comprising a substantially triangular wire disposed around a cable with the base of the wire contacting the cable, the apex of said triangular wire being formed with notches to facilitate bending of the wire.

6. A device to make an electrical bond betweena metal covered cable and a terminal which receives the cable comprising a substantially triangular wire disposed around a cable with the base of the wire contacting the cable, the apex of said triangular wire being formed with notches to facilitate bending of the wire and the base of said wire being knurled.

7. A device to make an electrical bond between a metal covered cable and a terminal which receives the cable comprising a strip formed with reduced areas to facilitate bending of the strip around a cable, said strip being formed intermediate oi said reduced areas with curved, projecting surfaces;

8. A device to make an electrical bond between a metal covered cable and a terminal which receives the cable comprising a strip formed with reduced areas to facilitate bending of the strip around a cable, said reduced areas being further weakened by having openings iormed therein and i said strip being formed intermediate 01 said reduced areas with ,curved, projecting surfaces.

9. In combination with a packed terminal, a cable disposed through the terminal and a terminal nut, an electrical bonding strip disposed around the cable within the terminal, said strip being in electrical contact with both the cable andthe terminal nut and said strip being formed with weakened portions to permit bending of the strip aroundthe cable.

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