Re: Matt Jeffries original shuttle design
I'm afraid you're both wrong here... The scissor element is called a torque arm and is used to stop the gear from rotating about the shaft... It is common on most larger retractable landing gear.
Everyone learns something new every day! I didn't know what that component was called, but Cary's right about it having multiple functions, depending on what type of gear it's on. BTW, I've also never designed any part of the landing gear, but I've been involved with just about every type of structure around it!B.J. isn't "wrong," by the way, and neither am I... that's why I asked what you intended for this to be, rather than just tossing out an answer.
For instance, on the Eagle, this would provide an extensibility limitation, and I know, from personal involvement, how the E-2C's front gear (which BJ found a great image of) works...
You're talking about a very complex piece of hardware... and "anti-rotation" is one possible function for that sort of device, but not the ONLY one. And, in fact, in most cases a device will serve multiple functions. Articulation? Maybe, on a spacecraft flat-pad landing foot (not so much for a rolliing-wheel aircraft landing gear). Part of the shock-absorption system? Absolutely (see the Hawkeye... carrier landing are VERY high-shock!). Extension-limiter? Almost certainly that will be, at the very least, a secondary roll (in case the primary strut limiter fails).
I know what BJ does... it's listed in his profile. And what I do is in mine as well. We've both worked on this sort of thing, though there are many people who know more about landing gear design than I do (my exposure to it has all been secondary in nature; I've never been the guy responsible for any aspect of its creation!)