 | | Mechanical pneumatic piston —Mike Thorn
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| | | Hello, A while ago I had a website bookmarked that showed how to build a mechanical piston replacement, mainly utilizing worm gears and half bushings as I recall. Naturally I've lost the bookmark now, so could some kind soul point me in the right (...) (21 years ago, 8-Oct-03, to lugnet.robotics, lugnet.technic)
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| | | | | Re: Mechanical pneumatic piston —Mario Ferrari
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| | | | (...) Hi Mike You probably mean Leo's translational joint: (URL) (21 years ago, 8-Oct-03, to lugnet.robotics, lugnet.technic)
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| | | | | | Re: Mechanical pneumatic piston —Philippe Hurbain
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| | | | (...) Hi Mike, A version I built a long time ago from Leo's idea, using a standard motor: (URL) (21 years ago, 8-Oct-03, to lugnet.robotics)
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| | | | | | Re: Mechanical pneumatic piston —Jordan Bradford
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| | | | (...) I once built one of these, just to see how it worked. It's pretty ingenious. I kept adding worm gears to see how big I could make it. Once you add more than two, there's a big gap in between the gears and the end of the housing you build for (...) (21 years ago, 8-Oct-03, to lugnet.robotics)
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| | | | | | Re: Mechanical pneumatic piston —Mike Thorn
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| | | | (...) Ah, that's it exactly! Thanks a lot. (...) Very interesting. Fairly small, and I imagine it moves pretty quick. Actually, in the application I want it for, it will be cranked by hand, so a motor isn't needed at all. (...) Hmm...I wonder why (...) (21 years ago, 9-Oct-03, to lugnet.robotics)
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| | | | | | Re: Mechanical pneumatic piston —Kevin L. Clague
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| | | | In lugnet.robotics, Mike Thorn wrote: [snip] (...) Nope. Worm gears are not an integral number of studs long. They are about 1/4 of a stud short. Not enough for a small pulley (1/2 bushing). (...) Kevin (21 years ago, 9-Oct-03, to lugnet.robotics)
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| | | | | | Re: Mechanical pneumatic piston —Philippe Hurbain
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| | | | (...) I'd be very interested to know the reason why LEGO choosed to make the worm gear so short :-( Philo (21 years ago, 9-Oct-03, to lugnet.robotics)
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| | | | | | Re: Mechanical pneumatic piston —Mike Thorn
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| | | | (...) Yes, it seems rather odd. It really wouldn't have affected the design of the gear at all. Just extend the spiral another fraction of an inch. Simple, really. If it's right that they're about 1/4 or 1/8 stud short, you ought to be able to line (...) (21 years ago, 9-Oct-03, to lugnet.robotics)
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| | | | | | Re: Mechanical pneumatic piston —Steve Baker
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| | | | | (...) The end of the helix on one worm gear lines up exactly with the start of the helix on a second worm gear. If the gears were a quarter stud longer, they wouldn't have this useful property unless Lego also changed the pitch of the helix. (...) (21 years ago, 10-Oct-03, to lugnet.robotics)
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| | | | | | | Re: Mechanical pneumatic piston —David Schilling
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| | | | | | | (...) If you look at the 1x4 rack (or any of the other sizes, for that matter) you'll see that actually there is more slop available than you'd think. The gears mesh with them fine, The worm gear similarly could have been stretched just a tiny bit, (...) (21 years ago, 10-Oct-03, to lugnet.robotics)
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| | | | | | | | | Re: Mechanical pneumatic piston —Dean Hystad
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| | | | | | | | (...) The gear rack has an advantage in that the teeth are parallel to the pinion gear's teeth. That ain't the case for the worm gear. The pitched worm interfaced to a pinion with normal straight teeth eats up most of the slop that you normally get (...) (21 years ago, 11-Oct-03, to lugnet.robotics)
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| | | | | | | Re: Mechanical pneumatic piston —Mike Thorn
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| | | | | | (...) I'm not sure I agree with that. It seems to me that if you made these worms from one great long string, all you need to do is cut them wherever you want a new one. The helii (is that a word?) would still line up. I don't see why they couldn't (...) (21 years ago, 10-Oct-03, to lugnet.robotics)
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| | | | | | | | Re: Mechanical pneumatic piston —Kevin L. Clague
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| | | | | | | (...) The problem is that you would need a mold for each unique part that is cut. If the number of rotations/divided by the length does not give you length that is repeatable using quarter turns you need more than one mold. This is *not* good (very (...) (21 years ago, 10-Oct-03, to lugnet.robotics)
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| | | | | | | | | Re: Mechanical pneumatic piston —Mike Thorn
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| | | | | | | | At 10:26 AM 10/10/2003, Kevin Clague uttered the following: (...) I'm not sure my brain can wrap itself around that, but I'll keep trying. In the meantime, I'll take your word for it that it won't work. :) Sometimes you LUGNET fellows are a little (...) (21 years ago, 11-Oct-03, to lugnet.robotics)
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| | | | | | | | | | Re: Mechanical pneumatic piston —Kevin L. Clague
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| | | | | | | | (...) I overspeaketh...... Let me try again. The gear has to be an integer multiple of 1/4 turns because the the gear can fit on an axle four different ways. If it is more or less than 1/4 turns (1/3), then things won't line up when you butt them up (...) (21 years ago, 11-Oct-03, to lugnet.robotics)
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| | | | | | | | | | Re: Mechanical pneumatic piston —Mike Thorn
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| | | | | | | | (...) Okay, I understand better now. So unless you have two worms made consecutively, you're stuck. Thanks! :) ~Mike (21 years ago, 11-Oct-03, to lugnet.robotics)
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| | | | | | | | | | Re: Mechanical pneumatic piston —Mark H. Near
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| | | | | | | | Restating for clarity, (I hope) I think the issue is the + shaped central hole. If you mounted these worm gears on an axle which requires them to be mounted at 0 (180), 45, 90, and 135, then of course you can't turn the gears anywhich way to line up (...) (21 years ago, 11-Oct-03, to lugnet.robotics)
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| | | | | | | | | | Re: Mechanical pneumatic piston —Gus Jansson
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| | | | | | | | | I have given this question some thought in the past and I came up with a theory. First of all some gear geometry background. Lego gears have 8 teeth per Lego unit (aka stud) of pitch diameter, the effective diameter to where the gears mesh. Using (...) (21 years ago, 12-Oct-03, to lugnet.robotics)
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| | | | | | | | | | | Re: Mechanical pneumatic piston —Ross Crawford
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| | | | | | | | | | (...) Very nice analysis! All seems perfectly logical to me! (...) The other problem is not having an axle long enough to put them on. So I connected them together with axles butting each other about halfway through each worm gear. And with 14 worm (...) (21 years ago, 12-Oct-03, to lugnet.robotics)
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| | | | | | | | | | Re: Mechanical pneumatic piston —Juergen Stuber
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| | | | | | | | (...) With four orientations that would be 0, 90, 180 and 270. However, you could get away with eight if you have one side of the worm gear at 0, 90, 180 and 270 and the other at 45, 135, 225 and 315, you'd just need to turn around every other gear (...) (21 years ago, 12-Oct-03, to lugnet.robotics)
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| | | | | | | | | | Re: Mechanical pneumatic piston —Mike Fusion
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| | | | | | | | sorry it took me so long to reply, working with remote administration and moving and other stuff.... anyways it has been my opinion that using the bushings has a tendency to slide when there is a slightly significany ammount of resistance involved. (...) (21 years ago, 28-Oct-03, to lugnet.robotics)
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| | | | | | | | RE: Mechanical pneumatic piston —Mike Thorn
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| | | | | | | (...) Hmm...yes, now I see. Unless you owned sequential worms, it wouldn't fit. Thanks for clarifying. Now I see what Steve was driving at. ~Mike (...) (21 years ago, 10-Oct-03, to lugnet.robotics)
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| | | | | | | | lego how to —Sonja Hänzelmann
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| | | | | | Hello everybody! Does anybody know, where I can get a good manual for the legorobot programming ind assembler? I need to know how to work with the rotating sensor and the IR from the RCX (not the IR sensor). Good would be something with Programming (...) (21 years ago, 10-Oct-03, to lugnet.robotics)
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| | | | | | | | Re: lego how to —Michael Obenland
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| | | | | | (...) I never saw something like that. Do you really want to write an Assembler program in H8 assembler? You could do that with the gnu toolchain, get all some informations regarding the H8 at: (URL) you want to use the Lego runtime system, you (...) (21 years ago, 10-Oct-03, to lugnet.robotics)
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| | | | | | Re: Mechanical pneumatic piston —Kevin L. Clague
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| | | | (...) Ah... I missed this post and asked the same question (less clearly) in another post. (...) Kevin (21 years ago, 10-Oct-03, to lugnet.robotics)
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