If you want to explore the geometry of valve gear do not miss this web-site.
It takes a little determination to get the demonstrations to work but the
effort is well rewarded.
http://www.tcsn.net/charlied/
Andrew Scott
At 05:49 06/07/01 -0400, you wrote:
>I spent some time researching this question at our Society's Library last
>night
>
>May I suggest the following references will at least give some basic
>information
>on the valve gear, even if they may not answer the detail question about
>the
>profiles of the stepped cams.
>
>Our Society's publications; "Locomotives of the LNER part 4 classes D25 to
>E7"
>does include several diagrams showing the general arrangements
>and workings of the valve gear as applied to the "Hunt" clas D49/2,
>it also explains the differences between the workings of rotary cam and
>oscillating cam versions.
>
>Probably the definitive technical presentation is that contained in
>Institution of Locomotive Engineers Paper number 248 of 1929,
>published in its journal number 90 of June 1929.
>
>This is entitled "Poppet Valves on Locomotives" by O.Bulleid
>(then of the LNER). This includes many photograohs,
>including one of the camshafts
>and drawings of the various arrangements used by the LNER.
>The discussion includes contributions on other designs,
>including photographs supplied by S.Caprotti.
>
>In 1930 there was a discusiion at the I Loco Engrs Leeds branch
> on this topic, led by E Poulteney, at which the journal states,
>many lantern slides and drawings were shown, but unfortuanetly
>these were not included with the "write up" of this meeting
>in Journral no 97. A number of other general surveys of
>valve gear developments may be found in later Journals,
>which might give some more detailed information.
>
>We also have an Associated Locomotive Engineers publication
>on Caprotti Valve Gear, which has a a small section
>on the Lentz valve gear, but no photgraphs o f that.
>It mentions that the agents for manufacture was the
>North British Loco Co, so there might be some detail information
>in their records.
>
>One of the sources mentioned above states that the valve design
>work was undertaken by Davey Paxman of Colchester,
>again I do not know if there records will have survived so many subsequent
>take-overs. Later part of Rustons or is it GEC or now even Marconi,
>it is so difficult to keep up with the company changes.
>
>As a retired engineer with some thirty years experience
>of working with diesel fuel injection systems, and for many years
>working on the design of cams and the associated problems,
>I have a particular interest in this enquiry. In the years before
> micro-processor controlled systems, I can remember working
>on the development of systems for both petrol and diesel engines
>which used either stepped or continuously variable cams.
>These were very succesful when hand matched to an individual engine,
>but the variability of the engine's requirements between samples,
>prevented these improvements being maintained in mass production.
>
>I hope these sources will be of help to the enquirer.
>
>Terry Silcock
>MA, CEng, MIMechE, AFIMA
>Librarian
>Railway Correspondence & Travel Society
>
>
Andrew Scott
Head of Museum
National Railway Museum
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