Castor wheel for holding up gate?

[Rgillard]

Hi guys,

My neighbour has asked me to make a barrier to close off the front of his silage pit. The problem is that the barrier can only swing one direction so that he can access the area. Its kind of tricky to explain. The thing is that he has a 28ft gate and the gap to be closed is around 40ft. What I was thinking was hanging this monstrous 28ft on a girder. On the free end of the gate I was going to put a heavy duty castor wheel which would be connected via a spring to ensure the castor was always in contact with the ground. On the free end of the gate I was also going to hang a small 12ft gate also. So the idea is tthat the whole gate will open in the same direction. Do you think a Cstor wheel would be up to take the weight of the two gates. Or if anyone else had another idea I would apprectiate their input.
Thanks,
Ronan.

 

[Rgillard]

Here is a small sketch of the yard. Might help get anidea of the problem

 

[wroughtn_harv]

Been there. Done that.

But what I had was a situation where the gate couldn't be long enough to close the opening because it had to be tucked out of the way. A slider wouldn't work so I made a folding swing gate.

It worked fine.

I made the primary gate strong enough to carry the weight of the second gate. And of course the pipe post was set so that it carried the combination without sagging.

There was the problem with the lack of rigidity in the first gate to carry the second gate when the second gate was open ninety degrees. The person doing the opening had to help the second gate at that point. /forums/images/graemlins/tongue.gif In that situation the caster wheel should have been on the second gate instead of the first.

 

[wroughtn_harv]

If the grade is relatively level I have another idea for your situation. Instead of using a caster consider building a triangular frame with a wheel at each end. So instead of having one wheel supporting the weight of the gates you'd have two. The hinge post will keep the gates up. And the two wheeled end on the big gate will enable the smaller gate to swing easily.

The idea is to have the end of the bigger gate strong enough to handle the weight of the shorter gate during it's whole swing arc.

If the ground isn't level you might have to replace the top hinge on the big gate with Heim (rod end bearing). Then the lower hinge needs to have either a smaller pin or a larger hole. This will allow the gate to move up and down on the end while keeping it in line.

 

[Soundguy]

Like the others.. I think the idea will work, depending on the strength and rigidity of the large gate. Castor kits are readily available.

You may want to consider a tension (guy) wire from a high point mounted at the main gate hinge post. Have that wire travel down to the top corner of the primary gate. ( should look like a right triangle.) This should offload some weight from the end of the primary gate.

Soundguy

 

[Rgillard]

Harry,
Could you do a simple sketch on paint so that I can fully understand your idea. The triangular frame certainly would add more stability to the gate. Would it need to castor?

 

[slydog]

I think Harv's idea is right on the money. I also like the addition of of the guy wire, however if you were resting the main gate on the double castor wheels, the ground should bear the weight of the wheels just fine, unless it very muddy. Perhaps instead of castor wheels which might dig into soft ground, you used some very small tires or wheels??? Something that would spread the load of the primary gate over the soft ground. Picture a trianglular plate with the apex pointing up. Then put a wheel at each of the bottom corners. Looking at the gate "end on" (the red post in the photo), the bottom of the gate would sit on the apex of the triangle. Not trying to steal your thunder here Harv, but I had an image program open on the desktop. Is this what you are describing somewhat?

Ken

 

[slydog]

Ooops...here's the picture.

Ken

 

[wroughtn_harv]

You got it Ken, darn, either I'm getting better at 'splainin' or ya'll gettin'n better at cipherin'. And your picture is definately worth more than my thousand words. /forums/images/graemlins/blush.gif

I'd like ya'll to think about something.

If you run that guy wire from the top of the post aren't you putting more leverage against the footing of the post?

But if you put that guy wire from the lower corner of the latch side of the gate back up to the upper frame near the high hinge aren't you accomplishing the same thing without the additional pressure on the footing?

Just a thot, harvey

 

[Soundguy]

I think that might put more stress on the gate itself. With the guy wire to the hinge post, and a castor, you can get by with a much flimsier gate. I've not seen this fellows 28 ' gate.. but most of the big gates I've seen were simple thin walled tube.. and not monstrously strong, save being able to carry their own weight.

You also wouldn't want the guy wire to carry the entire load of the gate.. but simply offload a few pounds, and let the wire be under some tension, but not full loaded.

Sure, this is adding a bit of stress to the post carrying the gate.. but then when i do fencing, the gate post is the biggest post I have, including the corner posts. I generally like 6-8x8 corner posts.. and bigger gate posts.. perhaps telephone pole material even.. whatever is big that I can lay hands to when I'm fencing. Fairly easy to get sizeable round timber around here, as lots of people like those 'big ponderosa' style ranch entrances.. materials in other regions may not be so easy to come by.

Soundguy

 

[wroughtn_harv]

I've got two thoughts for you to consider Soundguy.

1. If you noticed I mentioned the footing of the hinge post and not the hinge post itself. For every hinge post I see give way I see twenty footings.

Think of it like holding a pen between two fingers and exerting pressure on the end. Now take the same pen and grasp it firmly in the palm and exert the same pressure on the end again.

Most people think of a three foot hole for a hinge post as being adequate. For gates that aren't very long and don't weigh very much that works. A good rule of thumb is a foot of footing depth for every foot of post height for a hinge post if the gate isn't really heavy or really long.

2. The angle brace strengthens the gate. What it is doing is picking up the weight from the fartherest corner and attaching it directly to the high hinge pin.

I often see the angle brace from the lower hinge pin to the high corner of the gate. It throws the brace in compression and therefore needs considerable more strength than it does my way where it's in tension.

A couple of times a year I'll get to go out on a gate repair where sag is an issue. If it isn't the footing giving way and just the gate sagging I'll jack up the end and weld a half inch rod from top hinge to the bottom corner. It works.

If the hinge would be a visual distraction I'll use eye bolts, a turnbuckle, and stainless cable to accomplish the same thing. Everynow and then there'll be a gate where one either can't weld on it or really doesn't want to. Then some stainless hardware sprayed a matching color blends in without the worry of rust or being a visual distraction.

 

[Rgillard]

Soundguy,

The 28' gate is very heavy. I think it is a home made gate made out of 1.5" tube with a fairly heavy wall. The post for holding this gate up will be a girder which is at the corner of a shed and buried in a concrete wall so it will take a fair load i hope.

 

[Donman]

I don't know how much headroom you need thru the gate, but I would look into high posts on each side with a pulley system to raise the gate straight up rather than rolling a wheel thru cattle @*%!. You could use a crank and pulley system.

 

[Soundguy]

</font><font color="blue" class="small">( you noticed I mentioned the footing of the hinge post and not the hinge post itself )</font>

I did notice.. and I should have clarified.. but I was also considering that when I was talking about the hinge post.. as ther eis no need for a brute of a hinge post. if you are setting it into a material that won't support the weight ( soft ground.. etc ). So yes.. I was considering 'good' footing as just as important a factor as the strength of the post itself.


</font><font color="blue" class="small">( Think of it like holding a pen between two fingers and exerting pressure on the end. Now take the same pen and grasp it firmly in the palm and exert the same pressure on the end again.
)</font>

Yeah.. that's that 3' gate post example you mentioned ( I'm with you on that.... 1'st year engineering stuff.. )

</font><font color="blue" class="small">( The angle brace strengthens the gate. What it is doing is picking up the weight from )</font>

I got that to.. it's just that not every gate design can handle a welded brace, as you clearly point out later on.. many setups use the turbuckle and eye bolt idea.. especially the tube gates.

The guy wire idea is generally for even heavier situations where you need the mechanical advantage of a point higher than the top hinge on the gate. Sometimes a foot higer makes a huge difference. I like the cable or guy wire idea. You can make some nice setups using eyebolts that give the gate full range of motion without changing wire tension.

</font><font color="blue" class="small">( I often see the angle brace from the lower hinge pin to the high corner of the gate )</font>

That's just serving to load that bottom hinge more anyway.

One main problem I see is people not setting ther gat hinges correctly, and when they get the gate at 90' from the fence, they either have it wedged into the ground, swinging inthe air, or tilted top to bottom.

( I think we are saying the same thing.. )

Soundguy