US1284975A - Sanded insulator and method of making the same. - Google Patents

Description

A. 0. AUSTIN".

SANDEO INSULATOR AND METHOD OF MAKING THE SAME.

' APPLICATION HLED MAY 29. 1916.

1,284,975. Patented Nov. 19,,5918.v

2 SHEETS-SHEET liii/$55.9.-

A. 0. AUSTIN. ANDED INSUIJ ATOR AND METHOD OF MAKING THE SAME.

APPLICATION HLIED MAY 29. I9I6.

I ir/vzmssa' Q UNITED STATES PATENT OFFICE.

ARTHUR O. AUSTIN, OF BARBERTON, OHIO, ASSIGNOR TO THE OHIO BRASS COMPANY,

OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY.

,sammn INSULATOR AND METHOD or MAKING THE SAME.

To all whom it may concern.-

Be it known that I, ARTHUR a citizen of the United States, residing at Barberton, in the county of Summit and State of Ohio, have invented certain new and useful Improvements in Sanded Insulators and Methods of Makin the Same, of which the following is a specification.

This invention relates to insulators in which one or more of the parts have connected surfaces which are roughened or sanded to provide means for cementing the parts together and at the same time permitting greater resilience between them, and to the method of uniting or connecting such insulator parts so constructed. The invention consists in the novel method employed in connecting the parts and forming the insulators. and in the novel contraction, combination and arrangement of the several parts.

0. AUsTIN,

In the drawings, Figure 1 is a view, partly.

- shell coated with yielding material; Fig. 4

shows the adjacent portion of the insulating member so coated; Figs. 5 and 6 are detail views showing projecting particles attached to the insulating member; Fig. 7 is a view, partly in section, of a different form embracing the method and construction of my invention; Fig. 8 is an enlarged view of a portion of the construction shown in Fig. 7 Fig. 9 is an enlarged detail similar to Fig. 8, in which the sanded surfaces are continued between the parts; Fig. 10 is an enlarged detail similar to Fig. 8 with anelastic subtance interposed between the insulator elements, and Fig. 11 is a detail view similar to Fig. 8 embodying a previousl used method and construction.

In insulators which consist of a number of parts, either of similar or different materials, it is customary to unite the several parts by means 'of cement. The surfaces which are so connected may be knurled or grooved for affording more anchoring surface for the cement and thereby connecting the parts more rigidly together, but if the parts are too rigidly connected they may be lpeclflcation of Letters Patent. Application filed May 29, 1916. Serial No. 100,481.

Patented N 0v. 19, 1 918.

conditions which impair rather than improve the insulators. The unglazed surfaces provided with grooves, or plain, may give fairly satisfactory results but there are certain conditions which it is desirable to secure in insulators which can be better obtained if the surfaces are covered with glaze, not only where they are exposed to the weather but also where they are in contact with cement. Cement, however, does not adhere readily to a glazed surface on account of its extreme glassy condition, therefore to glaze the surface to be cemented still maintaining the grooves in the surface, as indicated in Fig. 11, would give desirable propertiesin the porcelain, namely, increased electrical resistance, but it would produce a joint mechanically weak ,which would soon break apart or loosen up on account of the cement not adhering to the surface.

To overcome this mechanical and physical weakness and to secure the properties which are desired in an insulator, it is found possible to coat the surfaces of insulating material to be connected before the insulatin member is fired in the kiln with material which will produce a glazed surface, and while this coating is still wet to sprinkle thereon sand or crushed material of substantially the same substance as that of the insulating member, which has or has not 35 been vitrified, but which will adhere to this coating on account of it being in a moist and sticky condition when first applied. Crushed unvitrified clay is preferable for the reason that if of the same composition as the body of the insulating member it will then have the'same coefficient of expansion and contraction in firing as the insulating member; itself since the two are vitrified at the same time, and therefore, there will be no tendency i ber itself is practically covered with glaze,

thus giving a surface which adds to the electrical resistance and prevents the absorption of moisture but. leaves the points of the '105 projection or particles projecting above the .glaze and'practically free of glaze at the outer ends, the bases and sides of the parti the roughened particles and the base of the projections. This leaves the 'end of the projections free to extend into the connecting cement practically free of the coating material so that they will engage the cement or-binding material between the parts. Since these projections are of considerably smaller area than the main body of the insulating member a force or. straln transmitted between the insulator parts or between a part and the cement will be concentrated in the projections. The projections being of elastic material and having a smaller section than the main body, the stress or strain tending toward disruption will be in inverse proportion to their cross sectional area and directly proportional to their length. It isevident then that if the projections are of sufficient length and of small enough cross section the internal strain or yielding stress between the main parts can be almost entirely taken up by these projections keeping .down the stress in the main insulating members.

, It is evident that there are a number of ways 'of obtaining this result, such as providing the members which are to be assembled together with ribs or a knurled or roughened surface. Where-metal parts are assembled with aninsulating member they may be prepared and treated the same way. ,A substitute for producing a rough surface of insulating material, such as porcelain or cement, as above described, is to roughen the surface of the insulating member before firin by means of a proper tool, such as a knur ing wheel, and as this surface is then glazed at the time of firing, the glaze produces a surface which is non-absorbent to moisture and has a higher resistance.

. As before stated, it is found that whenthe insulator parts through projections they offer a yielding r-ip upon the cement even though the proections may of-themselves be very brittle. This yielding grip is quite an advantage on account of permitting ex ansion and contraction ofthe cemented oint, thereby assisting to reduce strains in the assembled insulators through contraction and expansion from temperature changes and it has been found'that this yielding or elastic condition can be further increased by treating such nded or roughened surfaces with a semihard orelastic compound such as paraffin wax, or a quick drying elastic varnish, be-

fore the insulator parts are connected. This are cemented together semi-hard or elastic material is applied to the sanded surfaces and partially fills the recesses between the small projections by capillary attraction on such surfaces, as indicated in some of the detail drawings. This partial filling of the spaces between the projections still leaves the 'points or tips of the projections extending'beyond the semishown in the drawings.

For example, a portlon of an insulating member 11 in Fig. 5 is coated with a rather thick coating of glaze 9 in which particles connecting cement. If the glaze 9 is a thin coating, as shown in Fig. 6, the particles 13 will be less firmly held at the base, and will therefore be more resilient, the elastic coat- 1ng 15 then fillin the hollow between the pro ections as befbre. Quite a wide variation can be produced by changing the sizes of the particles. the thickness of the coating of glaze and the yielding material.

A surface thus prepared adds to the electr cal resistance, decreases the moisture absorbing property of the insulating material,

distributes the strain between the parts uniformly over the prepared surface, and produces a contact surface which is elastic or yielding as compared with the old method of connecting insulator parts directly with cement, as indicated in Fig. 7

If desired, this prepared surface with the sanded or roughened construction can be extended entirely over the surfaces in contact with the cement, as indicated in Fig. 9, but there is no particular advantage in having more than'the vertical sides of the insulator surfaces thus prepared and to sand the portions indicated with the reference numerals 16 and 17 in Fig. 8 would not materially increase the holdin effect between the two parts. Therefore, 1n order to preserve the elastic or'yielding properties the semi-hard or elastic materlal is extended over those surfaces whichv have no substantial gripping effect but to omit the sanded or roughened condition therefrom.

Referring now to Figs. 7 and 8, an insulator composed of two insulating parts 10 and 11 is formed with particles 12 and 13 constituting sanded or roughened surfaces which have been vitrified on the surfaces of the insulating parts and are to all intents and purposes integral parts of the insulathard or elastic-filling material, as clearly 50 jacent insulating material, thereby making ing members. These parts are secured to.-. gether by cement 14 which engages the extremities-of projections 12 and 13, as shown more clearlyin Fig. 8. The semi-hard or elastic material which fills the space between the projections at their bases is designated by the reference numeral 17 and the sharp points of the particles which. extend beyond the elastic filling material are indicated by the reference numeral16, for example in Figs. 8 and 10.

In some instances it is found advantageous to even increase the elastic condition the parts such as indicated etween the surfaces which receive a radial strain under expansion andcontraction of by the coated surfaces lfi' and 17in Fig. 8. This is done by inserting a disk 18 of yielding or elastic material, as shown in 10, or a heavy elastic. coating 19 as shown in Figs. 1 and 2, the disk18 being of yielding or elastic material such as felt, paper and the like.

This method of uniting insulator parts is not confined to use with insulators which consist only of insulating members but is equally applicable to-a structure, as shown in Fig. l, in which a metal cap 19' is cemented to an insulating member 20 and the, latter to a metal suspension pin 21. In this case the insulating member has a projcting boss 22 with a recess in whichthe' pin 21 is inserted, the inner and outer side surfaces of the boss being formed with sanded projections, as previously described,

and the metal cap and pin being formed with retaining grooves or depressions for anchoring the cement 14 thereto. Both of the cemented connections between the insulating member and the metallic members have the advantages of elasticity and resilience, as above set forth, to provide for the relative yielding due to expansion and contraction.

In addition, a ring 23 also of elastic material, such as felt, paper and the like, is interposed between the edge of the cap 19' andthe body or flange of the insulating member 20 for-allowing the expansion and contraction which may take place between the lower edge of the metal cap and the ada yielding contact between them and pre venting the surface of the insulating member from being checked or cracked due to the hardness of the metal, andalso for spacin I the edge of the cap and the flange apart.

Tnstead of providing a pad or gasket 23 the lower edge of the metal cap 19, as

. shown in Fig. 3, may be provided with a coating 25of yielding material which will effectually space the insulating member 20 and cap apart; or the adjacent surface of the insulating member may be. painted or coated with elastic material 26, as shown in Fig. 4, which serves the same purpose. In

either case, the formation of a bead or rim 14K of cement on the outside of the edge of the cap, does not form arigid strut between the cap and insulating'member, as the yielding material 25 and 26 is also'between them. The metal cap 19 may also be made thin at its upper portion 24 to provide a yieldable portion which will burst under pressure due to expansion or contraction, thus, relieving the pressure, without entirely separating the insulating member from the metal cap .and causing a mechanical break-down.

In Fig. 10 is shown a construction in which the insulator parts are formed with a roughened surface instead of sanding the glazed surfaces, asabove explained. In this case the glaze may be left oif of the roughened parts and merely an elastic coating 15 supplied, which as before set forth, collects at the bases of the roughened projections 16 leaving the points free to engage the cement 14:. c

The advantage of insulators constructed in accordance with this invention is that the projections formed are more or less resilient which tends to relieve the main insulating members of stress which may be set up between them, the projections thus distribof a considerable control, in the elasticity,

it holds the parts together firmly, and is cheaply made. By regulating the size of the projecting points, their number and the a coating material 1s readily seen that a wide range in elasticity may be provided for stresses applied to the point in either direc tion. Joints may be made by this method such that there will be no looseness between the parts but still they will have sufficient elasticity or give so as to relieve internal stresses or those due to applied load. Because of this greater elasticity insulators constructed in accordance with these principles are able to withstand the stresses due to expansion and contraction with less frequent breakage.

What I claim is: I

1. The process of making insulators hava ing a plurality of parts, which consists in coating adjacent corresponding surfaces with material which produces a glaze when the 1 the said coating before firing uneven par-' insulator parts are vitrified, in applying to vticles of the same material as that of which ing adjacent corresponding surfaces with a material which-will produce an adhering coating of glaze when the insulating, parts are fired; in applying to the coatingbefore firing uneven particles which will withstand the firing heat without distorting, and will adhere to the insulator surface and project above the coating, in firing the parts thus coated so that the, projecting particles will be uncoated with glaze; in coating the surface thus prepared with a yielding material and in applying cement between the said corresponding surfaces on top of the yielding coating to form a rigid connection between the parts and at the same time permitting of expansion and contraction thereof due to changes in temperature.

3. An insulator consisting of a plurality of parts having cooperating cementing surfaces, one or more of the surfaces having thereon an underlying glaze from which a there are projections; a coating of yield ing material reposing on the cementing surfaces and held in the spaces between the projections; and cement between the roughened surfaces of the parts to be united so that there will be a rigid connection but of sufficient resilience to permit of expansion and contraction without breaking the insulator parts.

4. An insulator consisting of a plurality of parts with corresponding cementing surfaces, the surfaces provided with a multiplicity of uneven, unglazed projections extending above a coating of glaze on the cementing surface, and by which the projections are made to form a substantially integral part of the insulator; a coating of yielding material reposing on the cementing surfaces but from which the projection extremities are substantially free; a pad of yielding material interposed between adjacent corresponding surfaces not roughened; and cement interposed between the roughened cementing urfaces for rigidly connecting the pro ections so that a yielding action of the insulator parts may be had due to the expansion and contraction in use.

5. An insulator consisting of a plurality of parts with corresponding cementing surfaces, the surfaces provided with a multi- H plicity of uneven, unglazed particles having projections extending above a coating of glaze on the cementing surface and by which the projections are made to form a substanexpansion and contraction in use.

6. An insulator consisting'of a plurality of parts, one or more of the parts being composed of an insulating material, the parts being provided with corresponding cementing surfaces and the insulating member having its cementing surfaces provided with uneven unglazed projections extending above a glazed surface and forming a substantially integral part of the insulator, a layer of yielding material reposing on the projections, and cement rigidly connecting the projections of one part with the surfaceof the adjacent part so that a yielding action of the parts may be had in case of expansion and contraction in use.

7. An insulator comprising a plurality of parts, each of which has a glazed cementing surface one or more of which has projections which extend above the glaze, a coating of yielding material for said projections, and cement interposed between the cementing surfaces on top of the elastic coating and engaging said projections to form a rigid connection between the parts which permits of expansion and contraction being taken up largely in the rigid connection so as to reduce stress in the insulator parts proper due to expansion and contraction.

8. An insulator consisting of a number of parts provided with corresponding surfaces for uniting the various parts, the corresponding surfaces provided with uneven particles having projections extending above and integrally attached to the surface by a layer of glaze, yielding material interposed between the surfaces of the parts not roughened, and a layer of cement connecting the projections on the roughened surface,thereby producing a yielding joint between the parts in case of expansion and contraction in use.

9. An insulator consisting of a numberof parts one or more of the parts having connectinc. surfaces provided with a plurality of pointed projections, a layer of yielding material reposing on the roughened connect- 12 mg surfaces at the base of the projections, and cement connecting the projections above the yielding coating to carry' the stresses between the insulator parts by the projections whichextend into the cement.

10. An insulatorcomposed of a plurality of parts having cooperating cementing sur faces, cement positioned between the cooperatlng cementing parts and one or more of the parts composed of a vitreous insulating 130 material, means distinct from the parts themselves projecting from the cementing ment between the connecting surfaces in which the projections are embedded so that stresses between the parts will be carried by the projections, thus relieving the insulating partsthemselves of internal strain.

12. An insulator consisting of a plurality of members, particles thereon with pointed projections, and cement uniting the members by connecting the outer ends of the projections thereby concentratingthe strain between the parts in the projections which are of comparatively small cross section, and relieving the main insulating members of stress due to uneven expansion or contraction of-the parts of material used in the assembly.

13. An insulator comprising a plurality of parts, one or more of which are composed of insulating material, means on the parts w whereby they may be assembled into a single unit, the means comprising a partly rigid and partly yielding bearing surface whereby the stresses in the insulator members due to changes in temperature will be minimized and the stresses will be concentrated in the rigid bearin surface.

14:. An insulator consisting of a plurality of parts having connecting surfaces which are roughened by projections, a coating of yielding material reposing on a part of the rou hened surface the remainln art of 9 b the surface being practically free of yielding material, and a fastening cement engaging the part of the projections free of yielding material and uniting the insulator parts, thus minimizin the stresses transmitted to' the insulating members proper due to changes in temperature.

15. An insulator comprising a plurality of parts having roughened projections on the surface to be attached to a part of the roughened surface leaving theouter extremities of the roughened projections free from such material, and cement connecting the arts by engaging the outerextremities of t e rough projections thereby minimizing the stresses transmitted from one insulating member to the other, and concentrating the strain in the connected projections.

16. An insulator of connected insulating parts, projections on the connecting surfaces, a yielding material reposing between the pro ections and parprojections, the points of joined, a yielding materialconsisting of a number tially covering the space therebetween, and cement interposed between the parts and into which the projections extend.

' 17. An insulator consisting of a number of parts, each part having a cementlng surface with projections therefrom, a yielding material reposing in the spaces between the the projections belng free of yielding material, and cement dlsposed between the points of the projections not coated, thereby reduclng the actual contact surface between the parts and concentrating the strain in the projections.

18. An insulator consisting of a number 7 of separate parts each having a connecting surface comprising particles with pointed projections extending from the body of the insulator and held thereto by av vitreous coating and forming a substantial continuation thereof, the cross section of the projections decreasing toward the end, and a cement interposed between lthe connected parts and between the extremities of such projections for concentrating the stress or strain due to expansion and contraction in the projections between the parts themselves.

19. An insulator consisting of a plurality of separate connected parts having cooperating connection surfaces each formed with projections substantially integral therewith decreasing their ends, a yieldingcoating applied to the projections and substantially filling the spaces at the bases thereof between the projections, leaving the extremities free of such' material, and a connecting cement interposed between the parts and contacting with that portion of each projection which extends above the yielding coating applied thereto.

20. An insulator comprising a plurality of parts, each formed with a glazed connecting surface and each having corresponding roughened surfaces formed by applying particles of substantially the same material as the insulator parts to the glazed surface before firing, and a connecting cement inter= .posed between the parts forming a substanan elastic coating applied to the projections and caused by caplllary attraction to collect at the bases of the projections, leaving the extremitles of the projections free from such in cross section toward a "plicity of small projections composed of the of nested parts cemented together, one or more of the nested parts composed of a vitreous insulating material having its cementing surfaces formed with a multisame material as the insulating members and held to the cementing surface of the insulating member by a vitreous glaze.

23. An insulator consisting of a plurality A of parts united by a cement interposed between adjacent surfaces and one of the parts being composed of an .insulating'm'aterial having its cementing surfaces formed with a multiplicity of projections composed of a material similar to that of the insulating member and attached to the cementing surfaces of the-insulating member by a vitreous glaze.

24. An insulator consisting of a plurality of parts united by a cement interposed between surfaces and one of the parts being composed of an insulating material having its cementing surfaces formed with a multiplicity of projections, and a yielding coating applied to the cementing surfaces and resting at the base of the projections leaving the larger portionof the projections free of the yielding material, the free part of the projections being embedded in the cement.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses on the 26th day of May, A. D. 1916.

I ARTHUR O. AUSTIN.

Witnesses A: J. CRANE, K. WV. WONNELL.

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