I have been asked to help with the design of a small (tiny) winch system intended for use in very harsh automotive road conditions.
This system is required to raise or lower an assembly with a total travel of about 18 inches. My task is to come up with a method of setting the upper and lower limits.
One of the options that we have come up with is purely mechanical: the winch motor turns a threaded rod (all-thread) which has a traveler nut. The nut hits a micro-switch at each end of the travel. Upper and lower limits are set by sliding the micro-switches to the appropriate position at each end of the threaded rod.
Although this system should be reliable, it is both large (long) and hard to seal. I'm trying to come up with something better.
Counting motor rotation is dead easy. This gives me a way to control the total distance that the winch cable travels. What I need is some method of coming up with an index point.
Suggestions gratefully accepted.