Tamas Juhasz Posted October 3, 2013 Hi! Some days ago, I created this autovalve: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=534632 My goal was to keep it small and reliable. If there is something, which can be build in a lot of variation, that's the autovalve. (If you don't know what it is: autovalves are made to remote control the pneumatic valves, the motor switches also the valve during making pressure with the compressor. The valve's position depends on the motor's turning direction) I needed as small autovalve as possible, and I also wanted to make something own. This one never can get stuck, I think this is the most important. Some other ones, I tried out, sometimes get stuck when I wanted to start them again or when they reached a special position. For working properly, it requires strong black pins ( http://www.brickshelf.com/cgi-bin/gallery.cgi?i=5955002 ; or the very old ones in 8842) if the valve is new, and hard to move it's lever. The pictures tell the working principle, I tried to make it very simple. The worm gear moves the 8t gear which is built together with the valve lever. The worm gear "ends", when the lever reaches one of the two final positions. The other 8t gear with the blue pin is for going backwards. Sometimes it doesn't needed, but without that it wouldn't be 100% reliable. There is a difference also between the blue pins, so if you choose well, it requires absolutely minimum power to turn. A little video: Share this post Link to post Share on other sites
jantjeuh Posted October 3, 2013 Smart! Looks even smaller than Sariel's autovalve. Share this post Link to post Share on other sites
Eigenbroetler Posted October 3, 2013 thats brilliant! Share this post Link to post Share on other sites
TechnicHead41 Posted October 3, 2013 A very clever design. Share this post Link to post Share on other sites
jantjeuh Posted October 3, 2013 Just built this (with some minor modifications to make it stronger), and it works flawlessly. Thanks! Share this post Link to post Share on other sites
skriblez Posted October 3, 2013 Very cool and small. Great work Share this post Link to post Share on other sites
kabelbinder Posted October 3, 2013 Wow, that is exactly the size I need. Thanks for sharing! Share this post Link to post Share on other sites
jorgeopesi Posted October 3, 2013 I like it, nice redesign . Share this post Link to post Share on other sites
jantjeuh Posted October 3, 2013 I just noticed it's not 100% reliable, the small gear can be forced off the valve lever by the worm gear. Trying to figure out a way to prevent that. Share this post Link to post Share on other sites
JopieK Posted October 3, 2013 That looks very, very nice! Share this post Link to post Share on other sites
Tamas Juhasz Posted October 3, 2013 (edited) Thanks all. I just noticed it's not 100% reliable, the small gear can be forced off the valve lever by the worm gear. Trying to figure out a way to prevent that. It's reliable, believe me. It depends on the gear: of course, a tight gear works well, a loose one which can slide easily on the axle isn't good. That's all. I built mine with a medium tight 8t gear, and there wasn't any problem during the lot of operation (about 100 times switched the lever). Sometimes it's important, to choose the "better" one from the same part, even the same have different geometry (micrometers), resistance (pneu valves), etc. You have to choose the ones which are best for the construction. Edited October 3, 2013 by Mbmc Share this post Link to post Share on other sites
aol000xw Posted October 3, 2013 I think I will use this in the future and if needed I will put a drop of white glue, the one that once dry is like rubber and you can remove leaving no traces. Share this post Link to post Share on other sites
Tamas Juhasz Posted October 3, 2013 (edited) I use it as can be seen in the pictures, and works well, I think it's better if you use a tighter 8t gear than glue. white glue, the one that once dry is like rubber and you can remove leaving no traces. You are right, but belive me, it's unnecessary. You even don't need a very tight gear, an average is enough. Even I didn't know about this "problem" until now, because it never happened to me. Edited October 3, 2013 by Mbmc Share this post Link to post Share on other sites
Splat Posted October 3, 2013 A similar design has already been shown on this forum by Zblj here. It is still an interesting design though, and nice and compact. Share this post Link to post Share on other sites
jantjeuh Posted October 3, 2013 (edited) Yeah, you can see Zblj has added an extra half bush on top of the valve lever to prevent the 8 tooth gear from popping off. Edited October 3, 2013 by jantjeuh Share this post Link to post Share on other sites
LiamM32 Posted October 3, 2013 I really like this design. It works so well for a motorized 2-way pneumatic pump. There could be much potential for derivative mechanisms for things other than pneumatics. I feel like I have wanted to make a gear mechanism similar to this in the past (not for pneumatics) but couldn't figure out how. It may have been for things like switches and steering (before the PF servo motor). One more thing that this could work for is for a 2-way gearbox mechanism, which is more reliable than other designs but with a slower response. Share this post Link to post Share on other sites
timslegos Posted October 3, 2013 I needed a tiny autovalve for one of my creations, and this is perfect! tim Share this post Link to post Share on other sites
Tamas Juhasz Posted October 4, 2013 (edited) Thx! A similar design has already been shown on this forum by Zblj here. It is still an interesting design though, and nice and compact. Thanks for sharing, it's new to me. From this case we can see one big truth: simple (basic) ideas can appear in other builders too. (We can only see, who published it first) Of course, Zblj is (also) "inventor" of this worm gear mechanism. I'm sure that will be others too. Yeah, you can see Zblj has added an extra half bush on top of the valve lever to prevent the 8 tooth gear from popping off. Ok, I write to YOU again: why should you use a bush+gear instead of a single tight 8t gear? As I wrote, with a good 8t gear there is just no popping off. The solution is so simple. Or you have only loose 8t gears? Edited October 4, 2013 by Mbmc Share this post Link to post Share on other sites
dikkie klijn Posted October 4, 2013 That is just brilliant, need to remember this one for future moc's Share this post Link to post Share on other sites
Lakop Posted October 4, 2013 A good design. I like it and will build one myself later. Thanks for sharing. H Share this post Link to post Share on other sites
andythenorth Posted October 4, 2013 This absolutely solves a problem I have with a MOC right now Share this post Link to post Share on other sites
afol1969 Posted October 5, 2013 I've already built an tested it on my logging truck, to make open/close the grapple. It works well, and indeed, you need a tight 8 tooth gear to prevent blocking or popping off. Greetings Alex Share this post Link to post Share on other sites
Tamas Juhasz Posted December 20, 2013 (edited) Last day I realized something: when I use this ( http://www.brickshel...ry.cgi?f=534632 ) autovalve with a new/tight pneumatic switch, it's able to click instead of moving the gear with the worm gear. It's no problem with loose pneu switches, but I want to make it reliable for every setup, so I rebuilt it into a V2 autovalve, based also on worm gear conception: Now it's 100% reliable, can't get wrong. The second worm gear holds up the pneu switch's lever. The pump isn't in the pictures, but it's easy to build in. Edited December 20, 2013 by Mbmc Share this post Link to post Share on other sites
