Untill Shif-key set at front (row) of the both side:right and left on the keyboard.

• 1875 Brooks patent, Filing date Dec. 30, 1875

  
  Patent US202923 - IMPROVEMENT IN TYPE-WRITING MACHINES - Google Patents:

• 1878 Remington No. 2, UpperCaseKey and LowerCaseKey
• 1878 Jan. 7 in England, 1879 June 23 applied in US
  • Yost patent.

  
  
  Patent US408061 - TYPE-WRITING MACHINE - Google Patents:

• 1879 June 23, Jenne patent.

  
  Patent US596371 - TO THE WTCKOPF - Google Patents:

• 1879 Aug. (ideal), Vincent F. Lake patent.

  
  Patent number: 344839 Filing date: Aug 12, 1879 Issue date: Jul 6, 1886
  Patent US344839 - TYPE-WRITING MACHINE - Google Patents:

• 1880 platen-shift-spring might exist. according to the instruction textbook.
• 1882 Remington Standard Type-Writer No. 2
• 1883 Wickoff maintenance instruction.
• 1888 McGurrin vs. Traub. McGurrin appear as touch-typist on the public mass-media.
• 1889 (Brooks patent with platen spring.) http://www.google.com/patents/US463724?
• 1890 Mrs. Barnes textbook
• 1894 Bates Torrey textbook
• 1894 Remington Standard Type-Writer No. 6

  
  Smithsonian Libraries: No Longer Fear Pen Paralysis!:

• 1896 Remington Standard Type-Writer No. 7
• 1897 Father and son of Wagner's patent:

  
  Patent US633672 - TYPE WRITING MACHINE - Google Patents: