LEGO SYSTEM Trains : 8451


Trains / 8451	8450 \| 8452

Subject:	motorized points - beating a dead horse
Newsgroups:	lugnet.trains, lugnet.robotics
Date:	Thu, 30 Nov 2000 23:03:56 GMT
Viewed:	1615 times

Hi All, Currently I am attempting to build an automated hump yard. The main problem I'm tackling is the RCX controlled motorized points. I've spent 7 hours over the last two days trying to build a motorized switch track that will run forever with out ripping itself off the base plates and be very *forgiving* at the edges of both states, turn or straight. What I mean by forgiving is that the motor doesn't burn up or the gears do not get stripped off. I like really simple and elegant solutions. For instance I would like to be CPU switched with no feedback, again forgiving at the edges of both states such that the motor can spin for 1.5 secs and not reap havoc. Hanging elaborate clutch systems with differentials and angle sensors would not be my first choice. Of course beggers can't be choosers. Yes I have tried a bunch of slip gear configurations and the 2.5N/cm doesn't seem to over come the internal detent. Yes I looked at several designs on the web, I could have missed something. After at least 10 iterations I am still staring at a desktop full of disassembled bricks. Any ideas? Help? SteveB PNLTC

Message has 6 Replies:

		Re: motorized points - beating a dead horse
"sebarile-MOBL" <steve.e.barile@intel.com> wrote in message news:G4v1EK.6yF@lugnet.com... (...) problem (...) over (...) forgiving (...) <snip> (...) If you don't mind a touch-sensor, you could try this one: (URL) automated point sports 1000+ (...) (23 years ago, 1-Dec-00, to lugnet.trains)

		Re: motorized points - beating a dead horse
(...) (note some heavyhanded snippage) Well, it wouldn't be entirely elegant unless you mounted the mechanics under your substrate, but if you were to gear down the movement so that the white clutch gear had to exert less torque to overcome the (...) (23 years ago, 1-Dec-00, to lugnet.trains, lugnet.robotics)

		Re: motorized points - beating a dead horse
Try putting belt drive stage in your geartrain so it can't destroy things and use touch switches to limit the travel... (23 years ago, 1-Dec-00, to lugnet.trains, lugnet.robotics)

		Re: motorized points - beating a dead horse
You could try my switch - (URL) out for Lego and Models ... I build this thing using a rubber-band so you can let it run without the switch destroying itself. Just let the motor run a view seconds until the point switches it's position. Michael (...) (23 years ago, 1-Dec-00, to lugnet.trains, lugnet.robotics)

		Re: motorized points - beating a dead horse
(...) I'm not exactly sure about your setup (I'm not into trains), but how about a small pulley (half bushing) on the motor, driving a medium pulley (with the six holes) on an axle on whose other end is an 8t gear that drives a rack. That setup (...) (23 years ago, 2-Dec-00, to lugnet.trains, lugnet.robotics)

		Re: motorized points - finally got it!
Yippy I finally got it! I have created a motorized switch track that ran 100 switches via RCX without tearing the housing apart or missing firing! After 100 I got tired of counting and I just stopped it, so it might go for several hundred. It sits (...) (23 years ago, 4-Dec-00, to lugnet.trains, lugnet.robotics)

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