Servo Operated Knuckle Coupling

thingiverse

This is a completely revised Knuckle coupling designed specifically for G scale garden Railways. Video is available at: https://youtu.be/kimp_JnspIU. (February 2020) A full set of non-servo Knuckle couplings has been uploaded to this platform for completeness' sake. I was not satisfied with the performance of my previous designs, and therefore decided to completely revise this version. Operation should be clear in the video provided. There is also a "fixed" version of the knuckle designed specifically for carriages etc., which is a simple one-piece part with integral plastic springing. These connect easily to each other and to the servo-operated version. Coupling to a train can have the moving coupling either open or closed. With it closed, more force (speed) is needed to connect. With it "open", coupling can be done at very low speed, but alignment of the two couplings is more critical. I used my RC-controlled Tram for the videos provided. The "cutout" versions of the housing and internal body will be required for some locomotives, unless you want to cut the loco body to fit the "standard" fully enclosed version. The iges files can be found at https://grabcad.com/library/servo-operated-knuckle-coupling-1. October 17th: I made a very small tolerance change to the disconnect lever servo holes, making it easier to fit the servo horn. Additionally, I moved the "connection axis" of the coupling 1.2mm to make for better coupling on the track. This revised the Main Hook and the Fixed Knuckle "FIXED_KNUCKLE_7DEG.st" part. For your reference, the 7 degrees refer to how "open" the fixed knuckle is. With a zero degree open part, the knuckles lock so tightly they cannot be easily parted. Seven degrees was a nice compromise, locking well but also allowing for release when required. To fit the Fixed Knuckle to your trucks and coaches, you will need to print (one of) the LGB housings available here: https://www.thingiverse.com/thing:1989545. Choose the housing that works best for your truck/coach etc.