US1937731A - Insulator - Google Patents

Description

Dec. 5, 1933. J TAYLOR 1,937,731

INSULATOR Filed May 26, 1932 INVENTOR Job/7 J. fay/0x BY W ATTOR Patented Dec. 5 v 1933 UNITED STATES 1,937,731 INSULATOR John J. Taylor, Barberton, Ohio, assignor to The Ohio Brass Company, Mansfield, Ohio, a corporation of New Jersey Application May 26, 1932. Serial No. 613,609

9 Claims This invention relates to electric insulators and especially to insulators which are subjected to high mechanical stresses and a wide range of temperature changes, and has for one of its objects the provision of an insulator which will withstand these conditions without injury to the dielectric material or other parts of the insulator.

A further object of the invention is to provide an insulator pin which will automatically compensate for differential expansion and contraction of the parts of the insulator so as to prevent undue strain upon the dielectric member.

A further object of the invention is to provide an insulator which shall be of improved con struction and operation.

Other objects and advantages will appear from the following description.

The invention is exemplified by the combination and arrangement of parts shown in the accompanying drawing and described in thefollowing specification, and it is more particularly point-' ed out in the appended claims;

In the drawing the figureis an elevation with parts in section showing one embodiment of the present invention. I

The numeral 10 designates a dielectric mem-,

ber which may be made of. porcelain or other suitable material. A metal cap 11 is secured'to the dielectric member by cement 12 and the outer face of the insulator is preferably provided with a treated sanded-surface at 13, as described in U. S. Patent #1284975, granted November 19, 1918 to A. .0. Austin. The'lowerportion of the cap may be thickened, as shown at14, and providedwith an inclined face 15 to provide a firm support for the portion of, the dielectric member subjected to the stress of a load and to prevent excessive. stretching of the cap under the expansive force produced by the load on the insulator. The dielectric member lO is provided with a recess having a coated sanded surface lfi and a pin 17 is secured in the recess by cement 18 The pin 17 is provided with one or more inclined bearing faces 19 and 20 which are approximately parallel to the bearing surface 15 and normal to the direction of the stress set up in the dielectric member by the load. The bearing faces 19 and 20 maybe given a coating of wax, bitumen or other'yielding material which will prevent the cement from adheringto the bearing surface and permitthe surface to slide on the cement to compensatefor differential expansion and 'contractionof the parts.

The cushion member 21 is placed above the upper end of the insulator pin to permit relative movement between the end of the pin and the inner end of the recess in the dielectric member. Below the bearing faces 19 and 20 the pin 17 is provided with resilient ' fianges 22 and 23. The

entire surface of the pin exposed to the cement vsating forthe expansion of the pin when the is preferably coated with wax, bitumen or similar material to prevent the pin from adhering tov inand cement to-compensate for load and to a heavy-load, it has a tendency to exert a bursting stress on thedielectric member 10 and ,in orderto prevent injury vt'o the dielectric member, the cap is provided with a heavy band 14. With this arrangement the stress in the dielectric member is confined largely to compression to which the porcelain-offers effective resistance.

If the cap 14 were made lighter so that it would expand, then the bursting stress would tendto expand the dielectric, placing the material under tension, in which the porcelain is relatively weak. it possible to support a heavy mechanicalload. The band 14, however, contracts at low temperatures and produces a pinching stress on the en-' closed dielectric member. qThis stress tends to break the upper portion of the dielectric member from the lower flanges but is overcome by the resistance produced. bythe pin; Ordinarily, the pin tends to contract at thesame time that the cap contracts, which would tend to relieve the pressure exerted outwardly by the load, thus permitting the dielectric member to be compressed and broken by the contraction of the cap. This tendency is overcome by the fact that the wedging surfaces 19 and 20 move downwardly in their sockets when the pin 17 contracts and thus main tains an abutment for withstanding the inward pressure exerted by thecap 14. The resilient flanges 22 will yield vertically under the stress of the load to permit the pin to move 'down- Wardlyand maintain a close fit between the cement and the wedging faces 19 and 20. When the temperature again rises so that pressure isrelieved from the outside and the pin. begins to expand, the resilient flanges 22 and 23 will assist. the upwardcomponent on the pin exerted by the The heavy band 14 thus makes wedging faces 19 and 20 and thus restore the,

pin to its initial position. If the pin were not provided with means for returning it to its in itial position andthe, friction of the surfaces 19 and 20 should prevent return movementgthen silient flanges 22 and 23 however insure a return of the pin toits original position, thus compentemperature rises.

The wedging surfaces 19 and 20 permit sufficient movement .of the pin in the direction of its axis to compensate for unequal expansion and contraction of the metal and dielectric parts and ,cap 14, tending to burst thedielectrici: The refailure of the pin to return to its upper position I after it has once been moved downwardly.

' In the embodiment shown in the drawing, the

of slightly less diameter than the. bearing surface so as to effect a graded distribution of stress between the pin and dielectric member-and so as to minimize any tendency forradial' expansion of the pin to crack the dielectric adjacent the upper endof the recess in the dielectric member.- This, however, is not an essential feature of the invention. The inner surface of the cap 11 is alsocoated with yielding material such 20 as wax or bitumen to prevent the cement from adhering to the surface of the cap and to permit the conical surface-15 to slide upon the cement to compensate for unequal expansionor contraction ofxthe parts. Usually it-is not necessary to 5 providehresilient means for restoring. the cap aftersa wedging action. The bearing surface of the cap is much larger than that of the pin so thatthepressure per unit'area is much smaller on the cap. 4 1

In addition to providing resilient means for restoring the pinafterlongitudinal movement thereof, theflanges 22 and 23 being larger than the steppedportions l9 and 20 assist in centering the pin whentheparts are assembled.

I. claim: J i

1,.An .insulatorcomprising a dielectric membenhaving aprojecting portion, a cap secured to .the outside of said portion, a pin extending intoa recess within said portion, a cement filler 'surroundingsaid pin in said recess, said pin 'hav- ""ingasolid, conical, bearing member at the upperend .thereof providing a rigid wedging bearing face engaging. said filler, the angle of said bearsipin having a solid, conical bearing member at 3.4 An insulator comprising a dielectric member,

a cap surrounding a portionof said dielectric .memberga pin disposed in arecess in said dielectricmember in registration with said cap, yielding means interposed between the end of said pin and. the. inner wallof said recess, .a solid, conical bearing. member on. the upperend of said pin hav- .fingfla rigid conicalbearing. surface, cement disposed insaid recessand providinga bearing 'surfaceicooperating. with the bearing surface of said pimmeans for preventing said cement from ad-- herins to the bearing surface on said pin, and a bearing surface in said cement.

bearing surface 19 adjacent the endof the pin is ward the end of said pin disposed in said recess,

cement. 1

resilient flange formed on said. pin below-said bearing surface and extending into said cement and tending to restore said pin aftermovement thereof in thedirection ofits axis to tighten said 4. An insulator pin having a rigid conical bearing surface, and a radially extending resilient flange. V I

5. An insulator comprising a'dielectric member having. a .recess therein, a pin having one end thereof extending into said recess, cement for securing said pinin said recess, said pin having a rigid conical bearing "surface at the inner end thereof, said surface being flared outwardly tomeans for preventing said cement fromadhering to said bearing surfaca and a radially extending resilient flange on said pin engaging said cement j and tending to restore said pin'after movement thereof in the direction of its'axisrelative to said."

6. An insulator comprising adielectric member; having a recess therein, a pin disposed in saidre i cess and having'a pluralityof; rigid conical bearing surfaces flared "outwardly toward the inner end of said pin, one'of said surfaces being dising surfaces, and a radially extending'resilient flange on saidpin engaging the cement to restore;

said pinafter movement thereof under the'force" in. the direction of the load-on said insulator; j

7. An insulator comprising a dielectric member and a metal fitting-member, said metal member having a rigid wedging surface'fortransmitting the load to said dielectricmember, cement bonded" to saiddielectric member and formed to provide; a wedgingsurface conforming to and-cooperating with the wedging surfaceof saidmetal member but unbondedthereto, and resilientmeans secured to said metal member and engaging saidcement and tendingtohold saidmembers in a predetermined position relative to each other and to re and resilient means on said metal member engage ing said cement for restoring members after. relative movement thereof under-the force of the load on said insulator. i Y' 9. An insulator comprising a dielectric member; a cap surrounding a portion of said dielectric member, a pindisposed in a recess in said dielectrio member and registering with said cap, a com: cal bearingmember at the upper end ofsaidgpin having a rigid, conical bearingsurface, cement, disposed in said recess about said pin and con 1 forming to and cooperating with the bearing surface of said pin, means for preventing said 'cement from adhering to the surface of said pin, and

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