Linear actuator in place of hydraulic ram?

[dsmiley]

There's no good reason to buy a 500lb actuator when a 1000lb unit is available. You need to consider the actuator's ability to resist simply failing and pulling apart from the extension loading exerted by the pallet. Your assumption that the lift links are carrying the load is incorrect. Prove this by attempting to lift the rear of a full pallet enough to slack your existing top link.

While I think something less than a 1000 lb might work I would not get less than a 1000 lb. The difference in price between 500 and 1000 is not that much. An AEI 1000 lb actuator with an IP66 rating is something like $170. I don't think I could do it hydraulically for that, not to mention having to mount a valve. The test you mention would be easy enough to do just to see how much it is loaded, out of curiosity. As I am thinking of this test we would have 2 different loads here, I think. If I do as you say and lift the rear of the pallet, this load will not be more than half the load of the pallet and forks. Lets say my forks weigh 100 lb and an evenly loaded pallet weighs 400 lb for a total of 500 lb. If I lift on the rear to loosen the top link I think it would be nearly half the total of 500 lb with the other half supported by the lift arms. But that force is a vertical one. The force at the top link is a horizontal force which I am thinking would be harder to measure. I'll have to think about that the next time I put the rear forks on. Maybe we have some engineers out there who could enlighten us. Anyway, some actuators have a static rating 3 times that of dynamic; that's why I was thinking a 500 lb one might work, but I wouldn't spend the money to find out.

[RickB]

While I think something less than a 1000 lb might work I would not get less than a 1000 lb. The difference in price between 500 and 1000 is not that much. An AEI 1000 lb actuator with an IP66 rating is something like $170. I don't think I could do it hydraulically for that, not to mention having to mount a valve. The test you mention would be easy enough to do just to see how much it is loaded, out of curiosity. As I am thinking of this test we would have 2 different loads here, I think. If I do as you say and lift the rear of the pallet, this load will not be more than half the load of the pallet and forks. Lets say my forks weigh 100 lb and an evenly loaded pallet weighs 400 lb for a total of 500 lb. If I lift on the rear to loosen the top link I think it would be nearly half the total of 500 lb with the other half supported by the lift arms. But that force is a vertical one. The force at the top link is a horizontal force which I am thinking would be harder to measure. I'll have to think about that the next time I put the rear forks on. Maybe we have some engineers out there who could enlighten us. Anyway, some actuators have a static rating 3 times that of dynamic; that's why I was thinking a 500 lb one might work, but I wouldn't spend the money to find out.

My gut says your estimate of 50% is low but I don't have enough of a formal physics background to participate in an intelligent discussion on the topic. So I'll just leave it at that.

[dsmiley]

Not to sound like a smart a**, but if it was that easy and cheap everybody would have them vs. hydraulic ones, and there would be 10 companies advertising here to sell them one.

Well, I think it would be a real small market since the largest actuator I've seen listed is 2000 lb. I think the 3-pt rating on your 4110 is rated for more than 1000 lb. So it looks like this would only work on the the smallest of tractors. I did a fair amount of searching and didn't find 1 thread on this. But I can't think of a single good reason why this wouldn't work in my application.

[Leejohn]

But I can't think of a single good reason why this wouldn't work in my application.

I think you well see when you start running over small pot holes. It well pull apart. The gearing in them is small.

[Willl]

But I can't think of a single good reason why this wouldn't work in my application.

I think you should go for it.

[RickB]

I think you should go for it.

Best $170 that somebody else could spend. So long as they report back, of course.

[DFB]

I just want to say I have used a hydraulic toplink for more than a decade on my tractor in every application from grading to snow plowing to tilling to brush hogging. It has more than proven itself Obviously there is more intial investment but I think its well worth it. My 4 way cross brand control was about $100. This thread got me looking at hyd toplinks again and saw this one toplink I thought the price on this short stroke was very reasonable longer stroke is only $20 more

[Grandad4]

But I can't think of a single good reason why this wouldn't work in my application.

If the applications simply involve adjusting or balancing a load being lifted and carried on the 3 point, it might work, at least for a while. Those are comparatively gentle uses for the 3 point, or should I say they ought to be comparatively gentle. There are many other 3 point implements, such as rear blade scrapers, box blades, middle busters, etc., whose operation places much more "violent" forces on the linkages. I wouldn't think an actuator type top link would be suitable for those.

[dsmiley]

If the applications simply involve adjusting or balancing a load being lifted and carried on the 3 point, it might work, at least for a while.

It's main use would be to level a load. However, I have had enough seeds of doubt planted so that I will probably not do it since it's cost might get me three quarters to an inexpensive hydraulic setup which I wouldn't worry about. But I'll always wonder if it would have worked.

Thanks for all the comments, guys.

[rockshaft]

I built an actuator grapple, and i use an actuator for my snow plow angle. Don't have any pictures handy of the grapple, as it was a fall project. Plow is in use and i've posted a pic or two on Green Tractor Talk. I got a good deal on some Bear Linear actuators, otherwise i probably would have gone the more traditional route of hydraulics. FYI, the units i own have dynamic load ratings varying from 1-2 thousand pounds, and static of 2k. In my case, they are no slower than hydraulic option. I've considered doing a toplink, and have a spare actuator if i decide to try it, but i suspect as others have noted, that the shock loading will reduce the working life of an actuator. Linear actuators aren't built for shock loads. If i try the toplink project, i may try incorporating some sort of heavy spring or other bumper.