Insulator Historical Timeline! 1880-1889

Key events are noted by approximate date.  Hyperlinks will provide additional information.  Please feedback additional key dates or note any needed corrections.  Dates considered particularly significant are highlighted in red.

• February 10, 1880:  Josephus C. Chambers of Cincinnati, OH patent for a combined decorative cresting and a lightning rod system.  The patent depicts CD 317 insulators used to support the system.  (US Patent 224,504) -- [Full Patent Text]
• May 25, 1880:  William F. Jobbins of New York, NY patent for a wooden insulator with an impregnated paper coating.  No known insulator has been attributed to this patent.  (US Patent 228,077) -- [Full Patent Text]
• June 14, 1881:  Robert Hemingray of Covington, KY patent for an insulator press (US Patent 242,825) -- [Full Patent Text]
• September 13, 1881:  Samuel Oakman patent for a process of forming threads on an insulator by plunging a previously formed (and cool) threaded glass cup into the molton glass in the mold.  The glass would cool enough as to not overly distort the threaded cup.  This technique was used by the American Insulator Co. on many of their insulators as well as some unembossed pieces and a CD 134 marked with just the patent.  This is the reason that many of these pieces have poorly defined or somewhat distorted threads, as the glass cup would soften in the molton glass.  (US Patent 247,100) -- [Full Patent Text]
• 1882:  The Pearl Street Power Station in service with 508 subscribers, Edison Electric Illuminating Co., New York, NY.
• May 1, 1883:  Joseph S. Lewis patent for an external thread above the wire groove to allow the insulator to be "screwed in" to a tie wire.  a damaged insulator could also be replaced without undoing the tie wire.  The patent drawing shows the threading to be in the same direction as a normal insulator's internal threads, making one loosen it on the pin to attach the tie wire (Not a desirable function).  Frank Pope's patent later this same year (Dec. 25, 1883) is for virtually the same design, only threaded in the opposite direction.  Both patents appear on the National Insulator "Corkscrew" styles CD 110.5 and 110.6.  (US Patent 276,839) -- [Full Patent Text]
• August 14, 1883:  Matthew Johnson of Ellenville, NY patent for an insulator press.  (US Patent 282,989) -- (Additional Patent Image) -- [Full Patent Text]
• August 14, 1883:  Homer Brooke, of Jersey City, NJ patent for an insulator press.  This patent was implemented on a number of Brooke's insulators including CD 120 and 133.1 and it is likely that this is the "patent applied for" on a number of other styles attributed to Homer Brooke including CD 120.2 and CD 125. Thanks to Bob Stahr for providing this data originating from Dick Roller who put together a great reference data base. (US Patent 283,321) -- [Full Patent Text] -- Link to additional Homer Brooke information.
• October 16, 1883:  Bradley A. Fiske and Samuel D. Mott patent for diamond shaped indentations in the wire groove to reduce electrical contact with the tie wire.  This patent was implemented in both CD 135 and CD 109.  (US Patent 286,801) -- [Full Patent Text]
• November 6, 1883:  Charles C. Hinsdale of Cleveland, OH patent for a composition insulator made from paper pulp.  No known styles of this unusual insulator have been found.  (US Patent 287,830) -- (Additional Patent Image) -- [Full Patent Text]
• November 13, 1883:  Samuel Oakman design patent assigned to the American Insulator Company.  This patent covered the double petticoat insulator and introduced the inner skirt! (US Patent 288,360) -- [Full Patent Text]
• December 1883: The Ohio Valley Glass Co. is incorporated at Bridgeport, OH to manufacture green glassware, bottles, flasks and fruit jars.
• December 4, 1883:  Necter Rousseau of Chicago, IL patent for a two wire insulator to allow a line break.  This insulator looks like it would have been a great transposition style, but was not intended for that purpose.  (US Patent 289,449) -- [Full Patent Text]
• December 25, 1883:  Frank L. Pope patent for external threads opposed to the internal to allow the replacement of a broken insulator without disturbing the tie wire.  This patent was implemented in CD 110.5 and CD 110.6. (US Patent 290,922) -- [Full Patent Text]
• January 1, 1884:  Edward J. Murphy patent for a technique to make the interior of the insulator.  The drawing showed a pinhole with a wider section at the top of the pinhole to lock the pin on, but the patent wording specifically did not exclude threading.  This patent was assigned to Laurence B. Gray.  (US Patent 291,072) -- [Full Patent Text]
• February 12, 1884:  Samuel Oakman of Melrose, MA patent for the beehive style of insulator (CD 145) - The one claim on the patent reads: "I claim - The design for an insulator herin shown and described, the body having the shape or configurations of the paraboloid transversed by an equatorial groove."  (US Design Patent 14,674) -- [Full Patent Text]
• March 31, 1884:  The American Iron Glass Pipe & Plate Co. was organized and they are believed to have started production late that year.  The National Insulator Co. CD 110.5 and CD 110.6 are attributed to them.
• April 22, 1884: Luther C. Baldwin and John C. Thurston of Manchester, NH patent for a pin locking scheme on a threadless insulator.  No known insulator has been attributed to this patent.  (US Patent 297,101) -- [Full Patent Text]
• April 29, 1884:  John M. Kline patent for an insulator pin design.  (US Patent 297,699)
• July 31, 1884: The Leonard glass works, of Detroit, Mich., is listed as making glass insulators in the Pottery & Glassware Reporter.
• August 19, 1884:  Emil F. Krell of Detroit, MI assigned three fifths to Orwell W. Owen patent for an insulator manufacturing machine.  (US Patent 303,936) -- (Additional Patent Image) -- [Full Patent Text]
• September 9, 1884:  Samuel Oakman patent for a hinged mandrill with a slot in the center to form threads in insulators - after the insulator was plunged, the center rectangular piece was removed from the mandrill freeing the two threaded halves to hinge together allowing removal from the insulator.  Many American Insulator Co. insulators are made with this patent. The top of the dome in these pieces usually has an imprint of the hinge.  Interestingly enough, the second patent drawing shows what looks like an American CD 105! (US Patent 304,748) -- (Additional Patent Image) -- [Full Patent Text]
• October 7, 1884:  Laurence B Gray patent issued for forming threads in insulators.  This appears to be a non-hinged implementation of Oakman's patent filed Sept. 9th.  This patent would also create an insulator with a slotted pinhole.   This resulted in a slotted pinhole with two slots as frequently seen on the CD 110.5 insulators.  (US Patent 306,146) -- [Full Patent Text]
• October 7, 1884:  A second Laurence B Gray patent with the addition of Joseph Ham as a co-inventor issued for forming threads in insulators.  This was filed a month later than the first and appears to be an enhancement of the actuation process used in the first patent.  The second patent had Joseph Ham as a co-inventor.  (US Patent 306,147) -- (Additional Patent Image) -- [Full Patent Text]
• January 6, 1885:  George W. Weyman of Philadelphia, PA  patent for an insulator press.  (US Patent 310,484) -- [Full Patent Text]
• February 26, 1885:  The Crockery & Glass Journal reports the Leonard Glass Works, of Detroit MI, filed suit to recover $8000 from the Chicago Insulating Co.  Possible indication on the maker of the CD 109 & 135?
• April 14, 1885:  Henry Prenzel patent for a two piece telegraph insulator.  (US Patent 315,660) -- [Full Patent Text]
• April 28, 1885:  John O'Brian of New York, NY patent for a unique insulator design.  This patent is incorrectly marked on the Brookfield CD 119 insulators -- They should be marked with another O'Brian patent on August 17, 1886.   (US Patent 316,812) -- [Full Patent Text]
• May 5, 1885: William H. Wright of Rochester, NY patent for an unusual insulator designed to contact the pin to provide extra strength.  No known insulator has been attributed to this patent. (US Patent 317,479) -- [Full Patent Text]
• June 9, 1885: George L. Broomhall of Paterson, NJ patent for a metal encased insulator to provide protection from rocks and bullets.  No known insulator has been attributed to this patent. (US Patent 319,447) -- [Full Patent Text]
• August 11, 1885:  James G. Pennycuick of Boston, MA patent for forming the threads on an insulator by leaving the plunger in the insulator through the annealing process.  This results in very crisp threading typical of the many various "Pennycuick" styles.  This patent is only embossed on some CD 134 "Diamond P" insulators, but was used to make many styles.  (US Patent 324,157) -- [Full Patent Text]
• December 8, 1885:  Benjamin Noel Deblieux of Bay St. Louis, MS patent for an unusual and somewhat complex two piece, no-tie insulator.  It is unlikely that an example was ever made.  (US Patent 332,061) -- [Full Patent Text]
• 1886:  First AC power plant in commercial service, Great Barrington MA.
• June 24, 1886:  The pottery & Glassware Reporter was informed by Mr. E. A. Leonard that the Leonard Glass Works of Detroit, Mich., has closed down and may not be reopened.
• August 17, 1886:   John O'Brian of New York, NY patent for a unique insulator design assigned to William Brookfield.   This patent was implemented in the Brookfield CD 119 insulators, although the embossing provides the wrong patent date.   (US Patent 347,635) -- [Full Patent Text]
• November 23, 1886:  Robert G. Brown of Brooklyn, NY assigned to the E.S.Greeley & Co. patent for an insulator and pin to allow mounting below the crossarm.  This design could double the number of circuits supported by a single crossarm or be used to facilitate wire transposition.  This patent style is known as the "Brown Pony" and was implemented in CD 187 & CD 188 as well as U-81, U-82, U-84 and U-85.  (US Patent 353,120) -- [Full Patent Text]
• July 26, 1887:  Henry K. Ruger of Bay St. Louis, Mississippi patent for a no tie insulator utilizing a slot to clamp and hold the wire.  This patent is very similar to the Charles R. Slusser patent filed over 20 years later!  (US Patent 367,164) -- [Full Patent Text]
• November 8, 1887:  Francis H. Soden and Henry Goehst patent for a strain insulator for electric lights.  This patent was implemented in the CD 1129 glass strain. (US Patent 372,940) -- [Full Patent Text]
• December 10, 1887:  Robert Hemingray signed a contract with Manufacturers Guarantee Fund Association to relocate the Hemingray Glass Company to Muncie, Indiana.  Link to additional details.
• 1889: The headquarters of the Bushwick Glass Works (Brookfield) was moved from 45 Cliff St. to 83 Fulton St. in Brooklyn, N.Y.
• May 7, 1889:  Fred M. Locke and John Lapp patent for a rams-horn insulator that would mount hanging down from a crossarm.  This patent was implemented in the glass CD 289.9 insulator, although I do not believe that the ramshorn piece has been found.  (US Patent 402,752) -- (Additional Patent Image)-- [Full Patent Text]

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