Insulator Historical Timeline! 1870-1879

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.

• January 25, 1870:  Homer Brooks of New York, NY patent for a press to manufacture threaded insulators.  Brookfield marks many of their earlier pieces with this date.  (US Patent 99,145) -- [Full Patent Text]
• February 22, 1870:  Reissue of the 1865 Cauvet's patent.  This date as marked on many early Brookfield insulators.  (US Patent Reissue 3,847)
• March 20, 1870:  "Hemingray Glass Company" was incorporated by an act of the General Assembly of the Commonwealth of Kentucky.   The first officers of the company were: Robert Hemingray, President; Ralph G. Hemingray, Vice President; and Richard Evans, Secretary-Treasurer.  Link to additional details.
• May 17, 1870:  Robert Breckenridge Baker of Philadelphia, PA patent for a metal and insulating material ramshorn insulator.  (US Patent 103,122) -- [Full Patent Text]
• May 31, 1870:  James M. Brookfield patent for a press to manufacturer threaded insulators.  (US Patent 103,555) -- [Full Patent Text]
• July 12, 1870: Orris W. Robertson of Milwaukee, WI patent for a battery rest insulator.  This was probably the first battery rest style and is similar to CD 61 which had previously been classified as a threadless insulator.  (US Patent 105,252) -- [Full Patent Text]
• July 26, 1870: William W. Baldwin of Cleveland, OH patent for a metal encased insulator.  No known versions of this insulator exist.  (US Patent 105,625) -- [Full Patent Text]
• July 26, 1870:  William H. Dechant patent for a hook or projection to hold a cylindrical insulator in a crossarm.  The insulator pictured in the patent drawing looked like a Brook's Ramshorn and the patent was for the projection on the side to prevent the insulator from dropping through the crossarm.   (US Patent 105,656) -- [Full Patent Text]
• July 26, 1870:  Samuel Oakman patent for a threadless slotted pinhole such that a wooden pin with a wedge at the top would be securely held to the insulator.  This patent was implemented on the Boston Bottle Work's CD 728.8 and the super rare CD 796 which matches the patent drawing!  (US Patent 105,834) -- [Full Patent Text]
• September 6, 1870:  Samuel McKee of Pittsburgh, PA patent for an unusual insulator with the outside threaded.  The insulator would screw into the bottom of the crossarm with the wire groove on the bottom.  No known specimens have yet surfaced.  (US Patent 107,075) -- [Full Patent Text].
• January 3, 1871: John Garity of East Birmingham, PA patent for a solid insulator (pin and insulator combined) designed to screw into the top of the crossarm.  This patent was implemented in CD 1040.  (US Patent 110,645) -- [Full Patent Text]
• April 4, 1871:  William Brookfield of New York, NY patent for an insulator press where the threaded mandrill was removable from the press allowing removal from the insulator later allowing a more rapid use of the press.  (US Patent 113,393) -- [Full Patent Text]
• May 16, 1871: Stephen Chester of Elizabeth, NJ for a metal ring with set screws to hold it to the insulator and three finger projections to hold the conductor to the insulator.  This patent was possibly used in conjunction with the CD 158.1 Chester insulator. (US Patent 114,924) -- [Full Patent Text]
• May 30, 1871:  Horatio Read of Jersey City, NJ patent for a threaded metal insert to be molded or cemented into the insulator to provide the threads.  No known specimens have been found made to this patent.  This patent may have had some relation to Brookfield, as the two patent witnesses both also witnessed several William Brookfield patents! (US Patent 115,521) -- [Full Patent Text]
• November 14, 1871:  George W. Kidwell of Elwood, IN patent for a two part glass block style insulator and mounting bracket.  (US Patent 120,884) -- [Full Patent Text]
• November 28, 1871:  Minard Y. Holley of Washington, DC patent for an unusual triangular insulator.  The idea is very similar to the Paul Seiler and Emminger patents issued later.  No insulator has been found that matches this patent.  (US Patent 121,368) -- [Full Patent Text]
• December 19, 1871:  Robert Hemingray patent for a technique for molding glass insulators.  This patent was used on a very large variety of insulators.  (US Patent 122,015) -- [Full Patent Text] -- (Additional Patent Image)
• 1872: Boston Bottle Works first listed in the Boston City Directory.  Samuel Oakman was very active with this company and undoubtedly involved in their numerous unique designs.
• January 23, 1872:  Chester H. Pond of Cleveland, OH patent for a threaded wooden insulator with a metal cap.  Several excellent examples of these insulators can be found in the Smithsonian archives.  (US Patent 122,961) -- [Full Patent Text]
• January 30, 1872:  John Robertson of Carbondale, PA  patent for a glass block style insulator and a wooden bracket.  (US Patent 123,198) -- [Full Patent Text]
• February 20, 1872:  David R. P. Emminger of Harrisburg, PA patent for a unique insulator design with four projections to hold the tie wire resulting in less contact area for leakage.  This patent was implemented in the rare CD 141.9 "Emmingers".  (US Patent 123,878) -- [Full Patent Text]
• September 10, 1872:  Henry C. Deemer and Joseph Eufinger of Brooklyn, NY patent for an insulator press.  (US Patent 131,153) -- [Full Patent Text]
• October 15, 1872:  Samuel Oakman patented an insulator threading technique that results in segmented threads which allow the threading mandrill to be removed without unscrewing.   This and the next related patent were initially used in the manufacture of Boston Bottle Works insulators.  This patent covered four segmented threads.  (US Patent 132,214) -- [Full Patent Text]
• October 15, 1872:  A second Samuel Oakman patent for segmented threading which was very similar to #132,214 but with three segments.  (US Patent 132,215) -- [Full Patent Text]
• July 3, 1873:  Homer Brookes files an appeal an a patent dispute with Hemingray and Brookfield between his January 25, 1870 patent and a Hemingray patent (assume the Dec. 19, 1871 patent) as well as Brookfield (assume the May 31, 1870 patent) all for insulator presses.  Brooks won the appeal and was awarded priority.
• December 30, 1873:  Christian Fox and Elisha G. Heston of Gap, PA patent for a two part no tie insulator.  A wooden patent model for this has been found and is written up in the July 2000 Crown Jewels of the Wire magazine (Front cover and pages 6-10).  (US Patent 145,997) -- [Full Patent Text]
• August 18, 1874:  Charles L. Le Baron of Pensacola, FL patent for a no tie insulator design.  No known styles have been attributed to this patent. (US Patent 154,258) -- [Full Patent Text]
• August 25, 1874:  Homer Brooke of New York, NY patent for a no tie insulator design.  What is surprising is how similar this is to the Harloe patent issued more than 25 years later!  (US Patent 154,451) -- [Full Patent Text] -- Link to additional Homer Brooke information.
• May 4, 1875:  Aries P. Brooke of Bayonne, NJ patent for an insulator press assigned to James Brookfield.  (US Patent 162,894) -- [Full Patent Text]
• 1876:  Alexander Graham Bell demonstrates the telephone at the Centennial Celebration in Philadelphia. 
• February 6, 1877:  Paul Seiler patent to provide six longitudinal ribs to both strengthen the insulator without adding weight and reduce the contact area with the tie wire.  This patent was implemented in CD 130.2.  (US Patent 187,183) -- [Full Patent Text]
• March 20, 1877:  James M. Brookfield patent for an insulator design that appears to be CD 127.  (US Design Patent 9,858) -- [Full Patent Text]
• May 8, 1877:  James M. Brookfield of Brooklyn, NY patent for an insulator design that looks much like CD 125 which I do not think Brookfield made!  (US Design Patent 9,956) -- [Full Patent Text]
• August 14, 1877:  Josephus C. Chambers patent for a unique lightning rod system using both CD 317 and CD 132.4 glass insulators.  An earlier version used CD 317.5 and CD 124.5 insulators.  (US Patent 194,220) -- [Full Patent Text]
• December 24, 1877: Thomas A. Edison files for a patent for the phonograph.
• 1878:  Edison Electric Light Co. incorporated in New York City to finance invention of incandescent lamp.
• March 19, 1878:  Joseph Matthewman of Brooklyn, NY patent for a screw threaded insulator.  This patent appears to be an attempt to work around the Cauvets patent by using very sharp almost vertical threads.  No insulators are known that can be attributed to this patent.  (US Patent 201,544) -- [Full Patent Text]
• March 26, 1878:  Walter C. Johnson and Samuel E. Phillips of Charlton, England patent for an oil insulator for telegraph lines.  (US Patent 201,615) -- [Full Patent Text]
• 1879:  Thomas Edison discovers carbonized cotton filament to make incandescent light bulb practical.
• January 14, 1879:  James M. Brookfield design patent for the CD 102 "pony" style insulator.  (US Design Patent 10,981) -- [Full Patent Text]
• July 8, 1879:  Burnley Taylor of Hanover, VA patent for a no tie insulator utilizing a metal screw cap to hold the wire in a slot in a threaded top.  No styles attributed to this patent have been found. (US Patent 217,427) -- [Full Patent Text]

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