Swing Gate

Cam Action - Swing Gate Illustration

  This diagram illustrates the principle effect of rotating an arc excentrically away from a similar arc. The net result is an increasing gap between the circumfrences of the two arcs.

  The use of this effect was discussed in an article called "A No Duckunder Layout Entrance" in the February 2013 issue of Model Railroad Hobbyist magazine.

  The dimensions shown are for reference only but do indicate ratios between the various components. The offset for the centre of 'gate cut line arc' rotation is increased for clarity but can be much closer to the 'centre of gate rotation.

With tight hinges and close componenet tolerances, the swing section could be made to jam itself in place when closed but still open with little effort/

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Please Read Before Using These Circuit Ideas

  The explanations for the circuits on these pages cannot hope to cover every situation on every layout. For this reason be prepared to do some experimenting to get the results you want. This is especially true of circuits such as the "Across Track Infrared Detection" circuits and any other circuit that relies on other than direct electronic inputs, such as switches.

  If you use any of these circuit ideas, ask your parts supplier for a copy of the manufacturers data sheets for any components that you have not used before. These sheets contain a wealth of data and circuit design information that no electronic or print article could approach and will save time and perhaps damage to the components themselves. These data sheets can often be found on the web site of the device manufacturers.

  Although the circuits are functional the pages are not meant to be full descriptions of each circuit but rather as guides for adapting them for use by others. If you have any questions or comments please send them to the email address on the Circuit Index page.

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09 December, 2014