Everything Old is New Again

Charles D. Schultz

President at Beyta Gear Service
Charles D. Schultz is President of Beyta Gear Service and one of Gear Technology's technical editors.

Latest posts by Charles D. Schultz (see all)

litvin-bookWriting a technical paper sometimes requires digging deep in your files for that obscure reference you just know you kept a copy of somewhere. I’ve been collecting books, papers, and magazine clippings for 43 years and remembering where things are after that amount of time and multiple job changes and relocations can be frustrating.

Even more frustrating is finding the sought after clipping and discovering it lacks the information needed to reference it in a peer reviewed paper. Contacting living authors is one thing; getting out the Ouija Board to contact others seems like a long shot.

An unexpected pleasure of this process is finding things I didn’t know I had. Such as a wonderful book (Development of Gear Technology and Theory of Gearing, NASA Ref. Publication 1406) by Prof. Faydor L. Litvin that included short biographies on people he thought were important to the development of gears. There is some impressive mathematical development early in the work that probably accounts for my forgetting that it was in my computer files. Included on that list of luminaries was the author of a book I had open on my desk at that moment, Prof. Earle Buckingham.

I have been a frequent user of Prof. Buckingham’s three volume master work, Manual of Gear Design. If you deal with epicyclic or planetary drives you too probably have pages 126-136 of Section Two memorized. I never bothered to look at other chapters in the book until prompted by another reference. It was a real shock to find that the Professor had taken the time to work out an entire system of high contact ratio gears back in 1935! While I had no illusions that I was breaking new ground with my Fall Technical Meeting paper, knowing that one of the giants of gear engineering had worked on the topic makes me sharpen my outline a little bit.

Have any of you had a similar experience in researching a new topic only to find that some of the hard work has already been done?

Comments

  1. John Summers says

    I am having trouble finding out when INVOLUTE gears were introduced, and what automobiles may have used the cycloidal system before switching to involute. Who really introduces involute gearing to the auto industry?

    • John Clatworthy says

      A good place to start looking is Leonhard Euler 1707 -1783, a Swiss guy appears on the old 10 franc swiss bank note. Some consider him the inventor of the involute. Of course, this was way before the auto industry.

  2. says

    It is difficult to establish accurate time lines for many gear systems since there were long periods of parallel use. I know from reading about the 1921 debate over adopting the 14.5 degree involute tooth form as a “standard” that the move to 20 degree stub in automotive and truck gearing was already underway.
    As far as cycloidal use, my understanding is that the involute system “took over” rapidly after generating tools like hobs became available. Hobs for involute forms have easier to make straight cutting surfaces while cycloidal tools require some curvature in the edge. When planing or milling teeth it would not be as difficult to get a cycloidal form. My guess is that cycloidal teeth were not used in auto or truck gearing after World War 1 because of the larger base of “modern” cutting tools that were then available.

  3. says

    American Machinist Gear Book by Charles H. Louge has an excellent discussion of the debate over “standard” tooth forms. Published in 1918 and revised in 1922, I found it for free download on line.

    http://books.google.com/books?id=339syGI6JW0C&pg=PA4&lpg=PA4&dq=cycloidal+gear+teeth&source=bl&ots=6MgMy9HrYN&sig=x9Dj93tVSy5LnnALmV9IyNVL65c&hl=en&sa=X&ei=RM4EU7qSDcSwyQHG-IHIBw&ved=0CFAQ6AEwCDgU#v=onepage&q=cycloidal%20gear%20teeth&f=false

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