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Subject: 
Suggestions wanted - auto-centring motor drive
Newsgroups: 
lugnet.technic
Date: 
Fri, 17 Aug 2007 11:49:11 GMT
Viewed: 
8413 times
  
I was wondering if anyone had a good, small technical solution to this problem.
It's for applications in remote-control steering and in other mechanical
actuators, like the tipping unloaders of Steve's GBC train wagons.

The idea is that, for steering a car, you provide motor power in either
direction and the car steers.  If you overrun the motor, the mechanism can start
to slip so it maintains the steering lock.  When you stop the motor, instead of
staying in place, the steering re-centres itself mechanically.

Similarly, you can use a motor to drive a lever down to its stop, whereupon it
begins to slip.  When you stop the motor, the lever returns to its former
position.

I presume this can be done by putting power to the outer block of a differential
gear, with the (spring-return) lever you want to operate on one output of the
differential, and a damped rotator on the other.  I can't think of a viable
damped rotator that can be built in LEGO though.  Of course if it's too stiff,
it could stop the restoring movement before it's complete.  Any suggestions?

If it's any help, I've found from trains that flex tubing makes a good centring
spring, as it likes to return to the straight position but doesn't provide a
greatly escalating force as it is deformed (like rubber bands or springs).  This
may not be an issue though with a direct motor drive, but it could help balance
the drive/restoration forces.

Jason R



Message has 1 Reply:
  Re: Suggestions wanted - auto-centring motor drive
 
(...) See (URL) for such a solution. But it works well only with low friction mini-motors. Philo (17 years ago, 17-Aug-07, to lugnet.technic)

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