US2310201A

US2310201A - Cable terminal

Info

Publication number: US2310201A
Application number: US296209A
Authority: US
Inventors: Frederick G Cox
Original assignee: General Cable Corp
Current assignee: General Cable Corp
Priority date: 1939-09-23
Filing date: 1939-09-23
Publication date: 1943-02-09
Anticipated expiration: 1960-02-09

Description

Feb. 9,v 1943. F.v G. cox

CABLE TERMINAL v Filed Sept. 25, 1939 INVENTR ATTORNEY Z d 5 6 4 48m. 0 MW l0 3 3 5 7 4 l 3 3 J 8 f ln 2 :f: 2. 9, im: 3 n lfn/ A 2 Patented Feb. 9, 1943 CABLE TERMNAL Frederick G. Cox, Metuchen, N. J., assigner to General Cable Corporation, New York, N. Y., a corporation of New Jersey Application September 23, 193i), Serial No. 296,299

10 Claims.

This invention relates to cable'terminals, particularly to insulated terminals adapted to connect oil-filled metal-sheathed cables to aerial conductors, and has for an object the provision of an improved insulated terminal which has allsoldered joints and which is free from cemented and gasketed joints for seal dependence.

A cable terminal of the type here considered is subjected to rather severe service requirements. Whether used indoors or outdoors it must prevent oil leakage even when the internal oil pressure is high. Also it must successfully resist the entry of moisture or water even when a vacuum exists within` the terminal. It should at the same time permit some expansion and contraction of the terminal parts. Moreover, it should give perfect service over long periods of time in order to avoid maintenance costs. On the last point the deiiciencies of cemented and gasketed terminals are most serious; because, even if they give perfect service for a while they will eventually fail through aging. The cement finally breaks due to expansion and contraction stresses which it cannot withstand; and gaskets become hard and leak with age.

An all-soldered joint, however, such as is provided by the present invention insures a perfect seal at the beginning and does not lose its eilioiency or fail with age.

The invention may best be understood from consideration of an illustrative embodiment thereof, such as that shown in the accompanying drawing, wherein:

Fig. 1 is a side elevation, partly in section of a terminal with cable connections;

Fig. 2 is an enlarged sectional View of the upper end of. the terminal; and

Fig. 3 is a similar view of a modification.

Referring rst to the form of terminal shown in Figs. 1 and 2, there is shown a hollow insulator I adapted to fit into a metal bell I3 which is connected as by a wiped joint I5 to the metal sheath 2li of an electrical conductor 2l The conductor may have insulation, such as paper 22, and may be provided with a stress cone II and metal shielding I2 beyond the cut-olf end of the metal sheath 20. Before the wiped joint is formed the space between the metal sheath 20 and the bell I3 may be lled as with a lead strip I4.

Packing 'I is inserted in the space between the outside of the lower end of the insulator` and the inside of the enlarged seat in the bell I3. Also, if desired, an asbestos pad 8 may be placed between the end of the insulator and the opposed shoulder of the bell.

In the region of the upper end of the bell I3 the insulator is metallized on the outside or is provided with an integral metal ring and the end of the bell is connected to this metallized ring by a solder joint 9.

The terminal may need to be secured to a support and for this purpose the metal bell is provided with bolt ilanges 23. A filling opening for the introduction of insulating fluid may be closed and sealed by a screw plug I I and a lead disc It soldered in the opening at the end of the plug.

A conductor stem 3 which is connected to the end of the conductor EI, as by soldering, passes out through the reduced opening in the upper end of the insulator Ill. Preferably this stem is provided with a filling and inspection bore 24 running along its axis with lateral branches 25 near its lower end and other lateral branches 25 adjacent the upper end of the insulator. The upper end of the bore 24 is closed by a screw plug 2 and a lead disc I which is soldered in place.

The upper end of the stem 3 is adapted to have a conductor lug 21 clamped thereon, the lug having a conductor 28 soldered or otherwise secured in a socket provided therein.

Around the stein 3 and above the upper end of the porcelain insulator i0 there is placed a metal top cap part 30 provided at its lower end with a lateral ange 3i. Between the lower end of the flange SI and the upper end of the insulator an asbestos pad or washer 43 may be secured. To the upper side of the flange 3l in a shouldered recess provided therefor the inturned flange of a top cap sleeve 6 may be secured as by soldering.

The skirt of the cap sleeve 6 is curved outward to provide for longitudinal expansion and contraction and to house packing 4l. The lower end of the cap sleeve skirt is flared to embrace the upper end of the insulator. The outer surface of the insulator in this region is metallized or provided with an integral metal ring, and the skirt of the cap sleeve is secured to this metal ring by a soldered joint 29. The packing 4l and the insulating washer 43 prevent the solder of the joint 2t from entering the assembly.

The top cap part 313 fits the stem 3 fairly closely but not tightly and is secured thereto by a soldered joint 4, the molten solder being introduced through a hole 4a in the sleeve and spreading around the entire space by capillary action. In order to prevent the solder from escaping downward, packing in the form of a Wound asbestos cord 5 may be placed in a groove in the stem 3 before the top cap 3l! is pushed thereon. A groove 33 is left in the upper end of the top cap 3B to receive the excess solder when the annular space between stem and tcp cap has been filled by capillary action. The presen-ce of solder in the groove gives the installer an indication that the space has been filled.

This terminal construction is very simple and eicient; gives full security against outward leakage of insulating fluid or inward leakage of moisture or water; permits all necessary expansion and contraction of parts; and will continue to be effective over unlimited periods of time without attention or repair.

For certain purposes it may be desirable to modify the construction at the upper end of the terminal. This modified construction is shown in Fig. 3. Here the stern 3 is threaded to take a hoodnut 35 to which the aerial conductor lug 7 for the conductor 28 is secured. For present purposes the hood nut may be considered part of the stem since it embraces the stem. Near its lower end .the stem may be provided with lateral projections or pins 3% which cooperate with recesses in the insulator it to prevent the sten:

from turning when the hoodnut is screwed on or on". The filling and inspection bore is not here illustrated but may be provided if desired.

The hoodnut '35 at its lower end is provided with a lateral flange 31 which is flared outward at its lower edge. Between the lower end of the hoodnut and the upper end of the insulator iii there may be disposed an insulating spacer 33 of a material such as Micartaf which preferably is somewhat larger in diameter than the end of the porcelain insulator. A heat resistant pad 39 of a material ysuch as asbestos may be placed between the spacer 33 and the end of the porcelain insulator.

A top cap 4 of thin spun metal such as copper is placed over the space around the ends of the hoodnut and porcelain insulator. rBhe central portion of the cap is corrugated as at @i to take care of expansion and contraction of the parts. The top of the cap 4l) is flared outwardly to cooperate with the flared edge of the flange 3l to form a solder groove. Packing, such as asbestos 42, may be disposed between the interior of the cap and the exterior of the upper end of the porcelain insulator to properly locate the cap and to prevent the inflow of solder.

The Voutsideof the upper end of the porcelain insulator adjacent the lower end of the cap is provided with a metallized coating or integral metal band and the lower flared end of the cap is secured to this metal band by a solder seal joint 43.

A washer-i4 of asbestos which fits tightly within the cap All to prevent passage of solder, may be secured between the spacer 3B and the lower end of the hoodnut. There is then formed between the upper end of the cap and the lower end of the hoodnut a groove which is filled with solder to form a joint 45.

In both embodiments the cap is soldered to the side of the porcelain insulator and to the side of the conductor post, the stem itself being the conductor post in the first case and the hoodnut which is screwed on the stem serving this function in the second case.

As Vfar as possible the solder joints on the porcelain insulators are made at the factory, leaving only metal to metal soldered joints to be made by the installer. For example, the joint 29 in Fig-2 andthe joint 43 of Fig. 3 may be made at the factory, and the joint 4 of Fig. 2 and joint 45 of Fig. 3 may be made by the installer. Where the bell cap for plural insulators is used, the joints at the insulators may be made at the factory and the joint between the cap and the bell made by the installer.

It is thus seen that the terminal made according to the present invention will satisfy the requirements for which it was designed. In use, terminals built in accordance with the invention have been found to meet these requirements in a highly satisfactory manner.

While certain embodiments of the invention have been described in detail to illustrate the principles of the invention, it is to be understood that the invention may have various embodi* ments within the limits of the prior art and the scope of the subjoined claims.

I claim:

l. A cable terminal, comprising in combination, an insulator shell, a metal conductor passing through one end of the shell, said conductor including a stem and hoodnut securing the stern to the end of the shell, a cap sleeve soldered to the shell and to said hoodnut, and packing means near the upper and lower ends of the sleeve to prevent the inflow of solder within the sleeve beyond the joints when the solder joints are made.

2. A cable terminal, comprising in combination, an insulator shell, a metal conductor passing through one end of the shell, said conductor including a stem and hoodnut securing the stem to the end of the shell, a cap sleeve soldered to.

the shell and to said hoodnut, and packing means near the upper and lower ends of the sleeve to prevent the inow of solder within the sleeve beyond the joints when the solder joints are made, said packing means comprising at the upper end of the sleeve, a washer which is secured beneath the hoodnut and which fits tightly within said cap sleeve.

3. A cable terminal, comprising in combination, an insulator shell, a conductor stem passing through one end of the shell, locking pins on said stem tting in recesses in said shell to prevent turning of the stem, an asbestos washer, a spacer washer, and a solder retaining packing washer around said stem on the end of the shell, a hoodnut provided with a base flange having a tapered bottom edge threaded on said stem and securing said washers against the end of said shell, a cap sleeve soldered to the tapered bottom edge of the hoodnut at its upper end, the packing washer fitting tightly within said cap sleeve to prevent the inflow of solder, packing between the shell and the sleeve, a solder joint between the lower edge of the sleeve and an integral metaliized ring on said shell, the packing preventing the inilow of solder, said sleeve being corrugated between its ends to accommodate eXpan sion and contraction.

4. A cable terminal, comprising in combination, an insulator shell, a metal conductor stem passing through one end of the shell, a metal cap connecting the shell and stem, the connection being made through solder joints at the ends of the cap with the shell and stem respectively, said cap surrounding the end of the shell and spaced therefrom sufciently to take solder and packing and being provided with a further enlargement adapted to take packing adjacent the end of the shell, and packing between the cap and shell above the end solder joint.

5. A cable terminal, comprising in combination. an insulator shell, a metal `conductor stem passing through one end of the shell, a metal cap connecting the shell and stem, the connection being made through solder joints at the ends of the cap with the shell and stern respectively, said cap surrounding the end of the shell and spaced therefrom suiiiciently to take solder and packing and being provided with a further enlargement adapted to take packing adjacent the end of the shell, and packing between the cap and shell above the end solder joint, said cap including a sleeve of thin material about the end of said shell and said enlargement being formed by a bend in the sleeve to provide longitudinal expansion.

6. A cable terminal as set forth in claim 4. which further includes packing between the stern and cap below the end solder joint.

7. A cable terminal, comprising in combination, an insulator shell, a metal conductor stem passing through one end of the shell, a gasket between the end of the shell and a facing part, a metal cap connecting the shell and stem, the connection being made through solder joints at the ends of the cap with the shell and stem respectively, said cap surrounding the end of the s shell and spaced therefrom sufficiently to take solder and packing, and packing in the space between the gasket and the end solder joint with the shell.

8. A cable terminal, comprising in combination, an insulator shell, a metal conductor stem passing through one end of the shell, a gasket between the end of the shell and a facing part, a metal cap connecting the shell and stern, the connection being made through solder joints at the ends of the cap with the shell and stem ren terial about the end of said shell, said sleeve being provided with an expansion bend adjacent the end of the shell.

9. A cable terminal, comprising in combination, an insulator shell, a metal conductor stem passing through one end of the shell, a gasket between the end of the shell and a facing part, a metal cap connecting the shell and stem, the connection being made thro-ugh solder joints at the ends of the cap with the shell and stem respectively, said cap surrounding the end of the shell and spaced therefrom sufficiently to take solder and packing, and packing in the space between the gasket and the end solder joint with the shell, said cap including a sleeve of thin material about the end of said shell, said sleeve being provided with an expansion bend opposite said gasket, and packing over the gasket within the bend in the sleeve.

10. A cable terminal, comprising in combination, an insulator shell, a metal conductor stem passing through one end of the shell, a gasket between the end of the shell and a facing part, a metal cap connecting the shell and stem, the connection being made through solder joints at the ends of the cap with the shell and stem respectively, said cap surrounding the end of the shell and spaced therefrom suciently to take solder and packing, and packing in the spa-ce between the gasket and the end solder joint with the shell, said stem including a flange facing the end of said shell over said gasket, said cap being formed as a thin sleeve about the end of said shell and said flange, said sleeve being flared at its ends to take the solder joints with the shell and said ange and being provided with an expansion bend adjacent said gasket, and packing in said expansion bend.

FREDERICK G. COX.