US1484051A - Insulator - Google Patents

Description

A. o. AUSTIN Feb. 19 1924.

INSULATOR 3 She ets-Sheet 2 Filed April 10 1919 mm N aw K M Feb. 19, 1924. 1,484,051 A. o. AUSTIN I INSULATOR Filed April 10 1919 3 Sheets-Sheet 5 Patented Feb. 19, 1924.

UNITED STATES 1,484,051 PATENT OFFICE.

ARTHUR O. AUSTIN, OF BARBERTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY.

INSULATOR.

Application filed April 10, 1919. Serial No. 289,092.

ject the provision of. devices of the class named which shall have improved mechanical reliability, thus decreasing the mechanical hazard of the constructions with which they are used and which shall be of improved construction and o oration.

The invention is exemp ified in the c0mbination and arrangement of parts shown in the accompanying drawings and described in the following specification, and it is more particularly pointed out in the appended claims.

In the drawings, Fig. 1 is a longitudinal sectional view of an insulator showing one embodiment of the present invention; I

Fig. 2 is a transverse section on line 22 ofFig. 1;

Fig. 3 is a transverse section on line 3-3 of Fig. 1;

Fig. 4 is a longitudinal sectional view with a part shown in elevation of a modified form of the present invention;

Fig. 5 is a transverse section on line 5-5 of Fig. 4;

Fig. 6 is a transverse section on line 6-6 of Fig. 4;

Fig. 7 is a transverse section on line 77 of Fig. 4;

F'g. 8 is a view similar to Fig. 4 showing still another modification of the invention;

Fig. 9 is a transverse section on line 9-9 of Fig. 8;

Fig. 10 is a transverse section on line 10 10 of Fig.8.

In many kinds of electrical power transmission and also in wireless work, it is of paramount importance that the insulators supporting the conductors shall not fail mechanically. The material of which the insulators are made, is generally of fragile nature, some form of vitreous material being most commonly used. The material-may be porcelain or the various forms ofearthenware or it may be any of the different kinds of glass. It may also be various other kinds of insulating materials having the requisite properties. The mechanical failure of an insulator in a high tension transmission line, for instance, not only endangers the lives of persons and animals in the direct vicinity of the failure, but may occasion hours of inaction in commerce and traffic depending upon the power transmitted over the line. The damage occasioned by the breakage of a single insulator which occasions the ground ing of a transmission line may, in some cases, amount to thousands of dollars before the insulator can be replaced, especially where the line extends through territory that is not easily accessible. The dielectric material most commonly used for insulators is subject to breakage and a rifle shot or even astone thrown by a careless person may result in the grounding of an important transmission line. In the present invention provision is made for holding the line in suspension even though an insulator be broken, thus avoiding the damage resulting from permitting the line to fall.

Under operating conditions the fragile dielectric may be. subjected to stresses of such magnitude that the material will crack in time. These stresses ma be produced by uneven temperatures in di erent portions of the material which may be occasioned by the sun shining on one portion while another is protected from same or by sudden and uneven cooling of an insulator from the suns rays or radiation when the sun sets.

The stress setup by uneven expansion in the dielectric itself, combined with stress set up by the working load and the difference in expansion between cap and pin, all tend to work the fragile dielectric on a very narrow margin of safety. 1 This small margin of together with the fragile nature of safety the ielectric, makes it almost certain that there will be some cracking and mechanical failures in time. Where large quantities of insulators are used it is almost certain that a singe tension member composed of a fragile dielectric, will cause entirely too many interruptions b dropping, the line. This may be reduce by using members in some multiple scheme as is now done or by a multiple tension member in the same insulator. Special advantagesare obtained where the multiple tension member isincluded in the same insulator. The principal advantages.

emperates under mu n more favoron than the outer member and consequently will have much greater eliabiiity than several multiple insulators, similar to -e outer member. T1113 single in sulator with safety core, has less breakage than a multiple insulator; simp ifies the construction and cost of installation a d permits of a higher electrical stand 7 ith the mechanical interlinked. core, i difficult to drop the line and even though he outer and inner members at cracked or damaged, the system usua y be operated until repairs can be made.

The increased reliability of the safety core type also permits of use of larger insulators or more insulators in series without danger of causing an excessive number of interruptions which might be the case where insulators of a single member are used.

The safety core with interlinked reenforcement or mechanical members is of particular advantage in providing protection from dama e due to shooting or rocks ascompared to simple fragile dielectric tension members used in multiple.

in Fig. 1 of the drawings, the numeral 11 designates a hollow tube formed from any well known dielectric, such as porcelain, and supported at its ends by metallic end caps 12 and 13. One of the end caps will be connected with the conductor to be supported while the other endcap will be secured to the supporting structure or a number of the insulators may be connected in series between the sup-port and conductor. The tubular form of insulator gives a maximum strength for a given cross sectional area and hence is well adapted for use in strain insulators. The walls of tube 11 may be thickened adjacent the end caps, as shown at 14 in Fig. 1 of the drawings, or they may be of uniform thickness, as shown at the left hand end of the figure; The thickening of the walls adjacent the end cap is for the purpose of preventing breakage adjacent the cap where the dielectric material is subject not only to the full stress occasioned by the load supported by the insu lator, but also to the shearing stress produced by the gripping of the cap upon the insulator tube. The end caps 12 and 13 are provided with sockets 15 and 16 through which pins 17 and 18 extend. The pins 17 and 18 support end caps 19 and 20, respectively, within the interior of the main insu'lator tube 11. The caps 19 and 20 support a supplemental tube 21 within the interior of the main insulator tube 11, and the tube 21, together with its supporting caps, constitutes. safety core for the purpose of sustaining the weight carried by the insulator in case the external tube 11 becomes broken. The walls of the supplemental tube caps in any 21 n .y be thi kened, as shown at 22, adj acent the edges of end caps, or the tube may be uniform. throughout, as shown at th opposite end of the figure fi' hcrc both the inner outer use have their walls thickened, this may ccomolished with the best economy of space by ing the increased material on the oute o the outer tube and on the inside of inner tube. it ill be understood, of urse, that although Lhis is a desirable arangement, it is not at all a necessary one, since the ends the tube could be reenforced in variety of different ways. The Lubes are cemented in their r spec e and well known manner. being common to roughen the interior of the caps and connect the tubes and caps by Portland cement or similar material. The ends of the tubes to which the cement is applied are preferably sanded in a manner described in my prior Patent No. 1,284,975 granted Novemberlt), 1918.

As shown in the drawings, the cap 19 is provided with an elongated slot 28 through which the pin 17 passes thus permitting a certain amount of play between the ends of the tubes 11 and 21. This lost motion prevents strain in the tubes which might be occasioned by unequal expansion or con traction if both ends of the tubes were rigidly connected together. The arrangement also places the entire load upon the outer tube so that if either tube fails under the stress of the load, the outer tube will fail first and the broken insulator will then be readily detected, while if the inner tube were made to support a share of the load and should fail under the stress upon it, the fact would not be apparent to one inspecting the line and the insulator would be left in place with the load depending upon the outer tube only without the safeguard o-f an inner core. 7

In Fig. at of the drawings a different'form of inner safety core 25 is provided which consists of a body having radially extending ribs or flanges 26. In the form shown in the drawings, there are four such flanges, but it will be undertsood that the number of flanges may be varied. The grooves be tween the flanges are provided at intervals along the length of the core 25 with cross webs or baflies 27 to interrupt any tendency to discharge along the grooves- It will be understood that a ribbed core of insulating material alone may be used, but in the drawings such a core is shown reenforced with a series of links 28, the longitudinal bars of the links being arranged to lie in the grooves between the flanges 26. The end bars of the links pass through perforations 29 through the central portion of the core and the perforations 29 are spaced from one another so that the end bars of adjacent links are separated by a portion of insulating material. The members 28 are interlinked with one another so that in case the core of insulating material should break the links 28 will form a continuous chain by which the conductor would be supported although possibly not electrically insulated from its support for the reason that the links 28 are preferably composed of metal and are therefore conductors of electricity. If however, the safety core is not entirely broken up, the conductor will still be insulated as long as any two of the links are separated by insulating material and even though the separating insulation may be cracked the insulating compound will tend to maintain its insulating properties. Of course the links 28 could be made of fibrous material which is nonconducting but in practice it is more practical to use metal for these parts. The

afiles 27 are placed in the grooves between the ribs26 so that a baflle occurs between each pair of adjacent links in a single groove. At the ends of the safety core 1 clevises 30 may be provided with pins 31 passing through one of the openings 29 in position to interlock with the end link 28 of the reenforcing members. The clevis 30 is formed integral with an end cap 32 cemented to the end of the safety core 25 and provided with an attaching pin 33 which passes loosely through an opening in the end of a cap 34 for the main insulator tube 11. The pin 33 is provided with a nut 35 secured to its outer end in position to permit longitudinal movement of the pin through the outer cap 34, thus preventing the load from coming upon the inner safety core so long as the outer tube is intact. A securing eye 36 is threaded into a socket 37 in the end cap 34 and is provided with a recess 38 which receives the end of the pin 33. The cap 34 closes the opening for I the pin 33 and thus prevents moisture from entering the interior of the insulator.

In some cases the nut 35 may be tightened to put the safety core under tension and the outer tube under compression. This Will tend to prevent breaking of the outer tube under stresses that may come upon it, because the material of the tube has an ultimate strength under compression many times as great as under tension. An initial compression on the outer tubewill help to overcome stresses tending to produce ten sion in the tube since the load to which the insulator is subjected must produce sufficient expansion of the internal member to overcome the compression exerted upon the tube before thevtube can be subjected to tension stresses.

In the form of the invention shown in Figs. 8 to 10, inclusive, the outer tube 11 is covered at its ends by caps 40 of insulating material having petticoats 41 for prevent ing flash-over outside the tube. Supporting end caps 42 are cemented to the exterior of the insulator end caps 40. A safety core 43, similar to the core 25, is provided with interlinking members 44 similar to the members 28. The chain of interlinking members 44 is connected to an end cap 45 by a cable 46 which interlinks with the end member 44 and which has its ends secured in sockets 47 formed on the end cap, the strands of the cable being spread out and filled with metal in a Well known manner to hold them in place. The end cap 45 is provided with a peripheral flange 48 which overlies the end of the tube 11 and is held within the cap 40 by cement 49. It will be seen that the insulator 11 and the safety core 43, when provided with this form of end construction, are connected rigidly together so that both will bear a portion of the load. In case of a break of the outer tube, however, the entire load may then be shifted to the inner safety core.

I claim:

1. In combination, a tubular insulator arranged normally to support a load and having a safety core therein normally free from said load but arranged to receive the load in case said insulator is broken.

2. In combination, an insulator and a supplemental safety member for receiving the load on said insulator in case said insulator is broken, said supplemental member having a loose connection with said insulator to prevent the load from exerting stress'upon said supplemental member while said insulator is intact.

3. In combination, an insulator constituting the entire support for the load thereon, and a supplemental insulatingmember connected with the load on said first-named insulator but free from the weight thereof, said first-named insulator being located relative to said supplemental member in position to shield said supplemental member from injury.

4. In combination, a tubular insulator having means connected with the ends thereof for supporting a load, and a safety core within said tubular insulator and having one end thereof normally loosely connected with said load-supporting means but arranged to sustain the weight of the load if said tubular insulator fails, said safety core being made of vitreous material.

5. An insulator comprising a tubular member having end caps secured to the opposite ends thereof, a safety core within said tubular member having one end thereof secured to the end cap for the adjacent end of 'said tubular member and having the opposite end thereof loosely secured to the end cap for the end of said tubular member adjacent said opposite end of said safety core.

An insulator comprising a tubular member, a safety core therefor of insulating material loosely connected with said tubular member to receive the load on said insulator only in case said tubular member fails, and means for supporting the load for said insulator in case both said insulator and safety core are broken.

7. combination, a tubular insulator, a safety core of insulating material loosely connected with said tubular insulator and normally free from the load thereon but arranged for receiving the load carried by said insulator in case said tubular insulator is broken, and a metallic support for receiving said lead in case said safety core is broken.

8. In combination, a tubular insulator, terminal fittings for said insulator, and a safety core Within said insulator comprising a rod of insulating material having longitudinal ribs thereon, said safety core being arranged to form a loose connection between said terminal fittings so as to permit the load to be normally supported by said tubular insulator but to receive the load from said tubular insulator in case said tubular insulator is broken.

9. In combination, a tubular insulator, terminal members for said insulator, and a safety core Within said insulator and constituting a lost motion connection between said terminal members, said safety core comprising a bar having longitudinal strengthening ribs thereon and having transverse flanges Within the grooves between said ribs.

10. In combination, a tubular insulator, terminal fittings for said insulator and a safety core therefor loosely connecting said fittings and arranged to receive the load from said insulator only in case said insulator is broken, said safety core comprising a bar of insulating material having longitudinal flanges thereon, and interlinking reenforcing members connected with said bar and insulated from one another thereby, said reinforcing members being ar ranged to receive the load from said safety core in case said bar of insulating material is broken,

In combination, a tubular insulator arranged normally to support a load and having a safety core therein normally free from said load but arranged to receive the load case said tubular insulator is broken, said safety core being made of vitreous material to prevent absorption of moisture if exposed to the Weather due to impairment said tubular insulator.

12. In combination, a tubular insulator arranged normally to support a load and having a safety core therein normally free from said load but arranged to receive the load in case said tubular insulator is broken, said safety core being made of vitreous material to avoid absorption of Water if exposed to the Weather and having interlinked metallic members to receive the load in case said vitreous material is broken.

13. In combination, a tubular insulator having attaching members fixed to opposite ends thereof so that said tubular member constitutes the entire support for a load on said insulator, a safety core comprising a rod of vitreous material arranged within said tubular member and having longitudinal strengthening ribs thereon, said rod having a lost motion connection with one of said attaching members so that said rod will receive the load in case of failure of said tubular insulator, and interlinked metallic members supported by said rod and insulated-thereby from one another but arranged to receive the load in case of failure of said rod, the links of said metallic members being disposed in the grooves between the ribs of said rod.

In testimony WhQIBOfI have signed my name to this specification on this 3rd day of April, A. D. 1919.

ARTHUR O. AUSTIN.

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