Linear actuator for power SSQA?

ovrszd · Mar 29, 2015

CDN Farm Boy said:
Is there any reason why it has to run a full stroke? I have zero experience with them but I can't imagine that they are built in such a way they can't stop mid stoke when the power is cut, nor is it designed to have constant power. Switch it with a spring loaded on-off-on then it only runs when you say so.

I agree with what you are saying. I was just thinking outloud. A self centering switch would probably be the best solution. With a click switch I'd be apt to forget it's running while waiting for it to complete cycle and leave the power on. I was just wondering if they are thermal protected at all??

Fallon · Mar 29, 2015

CDN Farm Boy said:
Is there any reason why it has to run a full stroke? I have zero experience with them but I can't imagine that they are built in such a way they can't stop mid stoke when the power is cut, nor is it designed to have constant power. Switch it with a spring loaded on-off-on then it only runs when you say so.

Ya, you can easily run them at a partial stroke. The problem is trying to gauge when the actuator is at the right amount of extension from say back in the seat. Some of the nicer actuators have an adjustable limit sensor on them. That would be ideal for running the actuator part way automatically.

Personally I'm looking for a more automatic solution, so the momentary double throw double pole switch would be annoying. I much prefer the fire & forget double pole double throw toggle switch I have.

As far as protection, many of them seem to have an overload clutch (this one, which is going on the other coop door does Amazon.com: 12-Volt Linear Actuator - Heavy Duty 225 lbs, 12" Stroke Black Finish: Automotive). Most seem to have thermal overload protection. Given the cheap Chinese nature of most of them & more so the descriptions I'm not sure if mine does though.

ovrszd · Mar 29, 2015

I think long term some sort of protection will become paramount.

So, when you flip the switch and then go about your business how do you know if the actuator stopped moving because it reached it's limiter switch or because it hit an obstacle it can't overcome??

If we can reach a solution for this problem I'm all about electric. If we can't, then hydraulic is preferred.

This is why they put compression springs on the locking mechanisms. So if you throw the handle into the latched position and for whatever reason the pin cannot fully latch, pressure is constantly applied by the spring until the action can be completed. No harm.

CDN Farm Boy · Mar 29, 2015

Fallon said:
Personally I'm looking for a more automatic solution, so the momentary double throw double pole switch would be annoying. I much prefer the fire & forget double pole double throw toggle switch I have.

As far as protection, many of them seem to have an overload clutch ....

Agreed that the flip and forget would be ideal IF the actuator is designed to deal with the constant power somehow other than just slipping the clutch at the end of the stroke

ovrszd · Mar 29, 2015

Yeah, an overload clutch is not the answer. There has to be thermal protection. And even that is not technically correct. The actuator should not be forced to thermally shut off each time there is a problem latching/unlatching. If it is forced to do that, it's lifespan is going to be very short.

Fallon · Mar 29, 2015

All of the linear actuators I've seen have limit switches. They automatically shut themselves off at the end of the stroke. So no problems leaving the switch "on". Some have adjustable limit switches, but those tend to be a lot more pricey. My current $60 actuator works like that with the fixed limit switches. Flip the switch one way & it extends until it hits the limit switch, then stops. Nothing happens (0 amps of current draw) until you flip the switch the other way.

CDN Farm Boy · Mar 29, 2015

That sounds good. Thanks for clarifying for those of us that have never dealt with them before.

Fallon · Apr 4, 2015

Apparently I left the 400lbs actuator in my amazon cart when I checked out & it arrived on Friday. I built the new brackets & tested everything out. Brackets are hanging while the paint dries. Only thing left is to let the paint dry, put it back together & get a bungee cord for a little better cable management.

The new brackets are just 2 chunks of bar stock each with 2 holes in them. 1 big hole with a bushing (thanks JMC) & one smaller hole to put a pin through to connect to the actuator. I left overhang on the back of the bar so the bar hit when the motor side was about to go over center. My first try extending the first bracket connected to the actuator & another bar on the other end ended poorly. The 2nd bar/bracket was a hair to long & as soon as both brackets hit the loader arms, unsurprisingly, the 15@ actuator popped the 10@ fuse. Replaced the fuse & trimmed the 2nd bracket so that there was at least 1/4" of slop total between the loader arms & the end of the brackets when at full extension. Works great now. I'll probably blow a fuse if I try to run the actuator with my ROPS lights on (same circuit), but it will provide good positive protection before breaking things.

The cheaper actuator works fine (as long as you get the 6", not a 4" like I did) if you don't mind it taking a little longer & my functional testing indicated that was not a problem. If anybody wants to pay shipping I'll send you my original brackets & the spare bushings I no longer need. You'll just need some longer bolts for the SSQA lever arms & a pair of captive pins or bolts to attach things to your actuator. Paint would be a good idea too.

Will post photos & video in a minute.