The Gravity Hinge

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The Lazy Farmer’s Gate.     

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Several years ago I was inspecting outside of a house and opened a gate to the back yard. After I walked through and let go of the gate, it closed by its self and self-centered at the latch post. It kind of surprised me so I had a closer look. What I found was that the bottom hinge had two pivot points. I had never seen anything like it and have never seen it since, but I liked it and was so excited, because I knew it could make my life easier.

Living on a farm, like we do, and having livestock, grandchildren and pets, like we do, there is always the possibility that something or someone will escape the fenced yard or field and end up on the road. Our farm has a perimeter fence all the way around it and the farm is crossed fenced, sectioning off different pastures. All gates open into our yard witch is located in the middle of the property. All gates open to the yard except the one at the long driveway out to the road. So if a donkey or a steer escapes a pasture through a gate that has been left open, or if they learn to unlatch a gate, which they have, the animal will be in the fenced in yard, but if the gate to the driveway is open, they could end up on the road.

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Okay, quick quiz; If there are three cowboys in the cab of a pickup truck, which one is the smartest?

Answer; The one in the middle because he never has to get out to open a gate.

The problem with having a gated driveway is that you have to get out, open the gate, drive through, then get out and close the gate. That is way too much work for a lazy man like me. To make things worse, when you live in the Willamette Valley, 70% of the time when you get out to open the gate, you’re going to get rained on. This is why I was so excited to discover the self-closing gravity hinge.

The premise of the gravity hinge is that the two offset pivot points of the bottom hinge will cause the gate to swing up as it swings open. Because it swings up as it opens, gravity will pull the gate closed into a level position. Very cool, I must say.

Showing how the gate swings up at the end when it is open.

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The idea is simple, but there were other factors that I needed to consider for our driveway gate;

  1. A 3’ garden gate is much smaller and lighter than the 16’ stock gate we have at the driveway, so the bottom pivot hinge would have to be much heavier duty.
  2. The gate latch had to be self-latching and when pressure was applied, self-unlatching.
  3. There had to be a way of stopping the gate from swinging too far open and popping off the bottom hinge.
  4. There had to be a bumper on both sides of the gate so it could be opened with a car and so the metal gate wouldn’t damage the car’s bumper.
  5. There had to be a soft bumper on the latch end of the gate so if the gate closed before a car could get through, the gate wouldn’t damage the side of the car.

I’ll address each of these issues one at a time.

  1. The hinge had to be heavier duty. The problem was that I couldn’t find the hinge for sale anywhere. So I made the two-part hinge out of steel plate and steel rods. I had no definite idea of what size I would need or how far apart the offset pivot points would have to be for a larger gate, so I guessed. A home grown engineer guess no less, because as it turned out, I was right on.                                                                                                                     Here are two tips on how to you make the two part hinge. In the part of the hinge that attaches to the gate , drill holes where the pivot rods will be. Insert the rods down through the holes ¼” and weld them in place to the plate from the bottom side using that ¼” that is sticking down through for the weld.

Drill holes slightly larger than the rods in the post side plate that will attach to the post then using a cutting torch or a steel cutting blade, cut from the edge to the holes.  (I hope my pictures and descriptions are explanation enough of how the hinge is made and works.)

Both parts of the hinge have to be very securely attached to the gate and post. To attach to the gate I used the female part of the original hinge, and bolted down through the plate and through the eye of the female part of the hinge. Then I drilled and bolted through the gate frame.

To attach the post side of the hinge I drilled two holes through the hinge, through the post and through a plate on the backside of the post.

  1. When you have animals that are smart enough and grandchildren that eventually get smart enough to open a gate latch, pushing a gravity hinged gate open is no challenge at all. I needed to make a latch that would open under pressure, but not too much and not too little pressure. The latch also needed to allow the gate to swing closed and self-latch. It’s amazing how my mind works and when I say amazing, I mean simple. My solution was once again, plastic barrel. I cut a piece of plastic about 8” wide and about 24” long. I then took the piece of plastic and wrapped it around the latch post and screwed it in place with about six screws, two on the back and two in each side. It’s like two arms reaching around the post and holding the gate closed from each side. Now when the gate closes, the gate will swing back to the latch and push one arm until it pops into center. The arm on the other side stops the gate from swinging open the other way. See, simple, but effective.
  2. Stopping the gate from swinging too far open was easy. I just drove two T-posts in the ground parallel to the hinge post and about five feet on each side of the post. To pretty them up I cut two pieces 2” plastic irrigation pipe about 5’ long and slipped them over the T-posts.
  3. To make the gate bumpers for each side of the gate I cut the same 2” plastic irrigation pipe 16’ long. Then I zip-tied them horizontal across the gate on each side of the gate at car bumper height.
  4. To keep the gate from possibly denting or scratching a car I cut a piece of that tubular foam pipe insulation about 2-1/2’ long, wrapped it around the latch end of the gate just below the latch and zip-tied it in place. Then I carefully wrapped the foam tube with electrical tape to protect it from damage and weather.

So this is how it works. You drive right up to the gate and stop. Take your foot off the brake and let the car idle forward against the gate. The gate will push against the far-side arm of the plastic latch until pressure on the gate causes the gate to pops by the arm and swings slowly and fully open. As it swings open, you simply drive slowly through. The trick is to drive at a speed so that you avoid hitting the gate again, causing it to fly open, hit the gate stop and come bouncing back against your car. When done properly the gate will slowly swing open, you’ll drive slowly through and the gate will swing close and latch.

We have found that it is best to open the gate and tie it or latch it to one of the gate stops if we know we have company coming. If we forget to open the gate, most drivers will make the cowboy sitting in the passenger seat get out and hold the gate open while they drive through.

Anyway…for what it’s worth.

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4 thoughts on “The Gravity Hinge

  1. Matt Spring

    This is a very cool idea. Simple yet effective, I had to blow up the picture of your hinge to get a better look, and I am impressed.

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