Welcome to our world of Locks and Locksmiths (click logo or scroll down to view all):-

 www.Antique-Locks.com 
HoL
Or are you looking for modern, or recent past,
Keys, Locks or Safes.
keys, locks & safes
Industrial Archaeology of Locks History of Locks Museum
Please support the HoL Museum Shop where you can.
Researching locks from antiquity to the recent past.Maintaining a reference collection & archive.
Results 1 to 3 of 3
  1. #1
    Join Date
    Jan 2013
    Posts
    640
    Country: United States

    Default Yale Duplex Master Lock in year of 1893 from Yale Book

    I have never seen these Yale Duplex lock anywhere as these was made in about 1893, but interest lock....Timothy.....

  2. #2
    Join Date
    Oct 2010
    Location
    Tonawanda, NY, USA
    Posts
    844
    Country: United States

    Default

    Quote Originally Posted by Timothy View Post
    I have never seen these Yale Duplex lock anywhere as these was made in about 1893, but interest lock....Timothy.....
    The Duplex Masterkey System was an early answer on Yale's part to the recognized problem of key interchange on split-pin masterkeyed locks* and perhaps for dual custody applications as well. This was prior to their introduction of the now discontinued Bicentric cylinder and Edward O'Keefe's invention of the Master Ring cylinder ca 1898. His patent was sold to P & F Corbin and they are still offered today by Corbin Russwin although not all contemporary hardware supports the larger diameter master ring cylinders.

    *this creates a second shear line in a conventional cylinder by adding a small wafer known as a master pin between the top and bottom pin, by putting master pins in multiple chambers; the number of random keys that will operate the cylinder are greatly increased, both the Bicentric and Master Ring cylinders negated this problem by eliminating the second shear line

    Pete Schifferli

  3. #3

    Default

    Quote Originally Posted by Pschiffe View Post
    The Duplex Masterkey System was an early answer on Yale's part to the recognized problem of key interchange on split-pin masterkeyed locks* and perhaps for dual custody applications as well. This was prior to their introduction of the now discontinued Bicentric cylinder and Edward O'Keefe's invention of the Master Ring cylinder ca 1898. His patent was sold to P & F Corbin and they are still offered today by Corbin Russwin although not all contemporary hardware supports the larger diameter master ring cylinders.

    *this creates a second shear line in a conventional cylinder by adding a small wafer known as a master pin between the top and bottom pin, by putting master pins in multiple chambers; the number of random keys that will operate the cylinder are greatly increased, both the Bicentric and Master Ring cylinders negated this problem by eliminating the second shear line

    Pete Schifferli
    This excerpt from my book Master Keying by the Numbers helps explain why the duplex by Yale was invented. It is important to note that at the time Yale was the only manufacturer of pin tumbler locks.

    "The first master key system which was scientifically written for the pin tumbler cylinder was written using the rotating constant method. The Yale Lock Company catalog number 12 of 1889 offered a master key system for five pin cylinders with agrand total of 16 change keys.

    Indications are that prior to that offering, they were supplying master key systems based upon the shoebox method described in sectionD, part 3, or something like the Yale duplex lock invented in 1878. Because not everyone wanted two cylinders on their door, or the interchange which results from the shoebox method, a scientific approach was discovered.That approach has been refined and is known today as the Rotating Constant Method.


    BBE.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •