Using garden gate motors and drives.

[ollypenrice]

Our first automated sheds used cycle-chain-drive electric garage door openers. They worked reasonably well but the electronics didn't like the cold and they became increasingly suspect. We converted the big 4-scope shed to a rack and pinion garden gate opener, which worked fine. The toothed rack was screwed onto a horizontal wooden beam on the roof. It worked fine and still does. However, when we converted the next two automated observatories to this system it proved difficult to get a consistent mesh at the rack and pinion because of warpage on the rack-carrying beam. Seasonal changes kept causing the mesh to be too tight or slack. 

I've just rebuilt the garden gate mechanism on one of the sheds so that a hefty single length of angle steel (4.5cm per side) now sits on top of the original wooden beam and the toothed rack bolts to that. This has cured the warping problem, it would seem. If you're aiming to use this system I would suggest using a steel support for the rack. It is also much easier to set up. Firstly I attached the rack to the steel and then put a single screw half way along the steel to attach it to the roof beam. I could then pivot it horizontally on that screw to get both ends of the rack (and the middle) the right distance from the motor. That's to say precisely parallel with the rails. Adjusting the rack up and down was easy because I had open access to the nuts on the bolts fixing rack to steel. Ignore the white arrow! That was for the owner of the system inside. In the finished version none of those bolts is missing.

The last job was just to put 60mm of ply under the motor to lift it to the new height of the rack.

Olly

[old_eyes]

Good solution Olly. My rack is bolted to the 25mm square section tubing that my roof frame is made out of. That works fine, but I get a little movement in the 75mm sq bearing beams that carry the F H Brundle track that the wheels roll on. So far it has not locked up, but in runs more freely under some weather conditions than others. If it gets a problem, I think I will replace those track carrying beams with recycled polypropylene fence post material. That will be completely dimensionally stable (at least compared to wooden fence posts!).

[rodrigol]

Very cool and interesting variation. I did something very similar and ended up with what you see on the video in the post below. So far no big issues except for the bad weather. These garden gate motors are really neat and reasonably quiet. My only problem - more a worry - is that the start of the open or close run is very hard. I wish there was a slow start setting. 

Hmmm. Look at that. It's clear tonight and I've been working all day until now. Argh. I'm dying to get out to test my new setup, which includes a NUC on top of the scope and that controls everything using NINA. To be or not to be.

 

 

[Kimboman]

Great topic Necessity  brings ingenuity

[ollypenrice]

On 22/01/2021 at 01:23, rodrigol said:

Very cool and interesting variation. I did something very similar and ended up with what you see on the video in the post below. So far no big issues except for the bad weather. These garden gate motors are really neat and reasonably quiet. My only problem - more a worry - is that the start of the open or close run is very hard. I wish there was a slow start setting. 

Hmmm. Look at that. It's clear tonight and I've been working all day until now. Argh. I'm dying to get out to test my new setup, which includes a NUC on top of the scope and that controls everything using NINA. To be or not to be.

 

 

Our system does have soft start and stop built into the mechanism as supplied.

Olly