Remote control for gate release / auto closer

[Shimon]

Our sheep are getting more and more wily each year and it's hard to get them penned up in their shed so we can administer vaccines, trim their hoofs, shear them, etc.... I put in a new, light weight gate and I want to be able to close it with a remote control "key-fob" from a distance. The gate will have three or four bungee cords attached so that when the gate is open, it will naturally want to close shut. I will then have a latch mechanism that holds the gate open. When I press the remote control, a 12VDC solenoid will pull the latch allowing the gate to shut. If the gate doesn't close quickly enough, I can tighten the bungees, add more bungees or even install one of those gate spring closer things. Power will be supplied from a 12VDC power brick (from an old laptop) that will plug into an outlet in the shed. The components will be mounted in a sealed plastic J-box with the receiver antenna and solenoid mechanism sticking out.

This is the solenoid I plan on using: Guardian Electric - LT6X12-I-12D - Solenoids - Solenoids (Mechanical Actuators) - Allied Electronics
This is the remote I was planning on using: Remote Control On/Off Switch - LEDs, 12 volt accessories

Here is a diagram of the latch and parts:



Here are some photos of the gate:





So, any suggestions? Not sure if the solenoid will be strong enough, but I can always find a stronger one from Allied or I can use an old stop-solenoid from a diesel Ford Lehman engine...those have quite a pull but also draw about 20 amps. I would like to keep the solenoid under 4 amps so I can use a 12V power brick I have laying around. Also, any suggestions regarding the remote would be appreciated too. Or any suggestions/comments about the design in general. Thanks!

 

[bcp]

You can use a small solenoid by not having it operate the latch directly. Design it like the trigger and sear on a gun, holding back a powerfully sprung firing pin. A very small force releases a very powerful spring.

Bruce

 

[jwmorris]

I know exactly what you need, the electric truck latch out of a wrecked car. No matter how much "spring" you put on the gate it won't bind and they draw less current than a solenoid would.

 

[Shimon]

I know exactly what you need, the electric truck latch out of a wrecked car. No matter how much "spring" you put on the gate it won't bind and they draw less current than a solenoid would.

You meant "trunk" latch right? I like this and will investigate. There are a number of wrecking yards around here...I'm sure I can find something.

Thanks for the replies.

 

[Jasonc87]

If it came down to a draw problem shimon as in too much for the PS your wanting to use, you could always do a small 12v battery with a battery tender to keep it alive. Then the rest of your plans would remain the same. It wouldn't even have to be as big as a lawn tractor battery really and it could take pretty good short draws.

 

[Wyobuckaroo]

How about a drop gate on the remote.
And a normal swing gate for the other 99.9% of the time you go in and out......

Good luck

 

[jwmorris]

Yes, trunk latch. Dam cell phone up date auto correct is going crazy but it is the easy way to take and up load photos.

Like this.

 

[Shimon]

Yes, trunk latch. Dam cell phone up date auto correct is going crazy but it is the easy way to take and up load photos.

Like this.

Thanks for the photo. I agree about the "smart phone" comment. Sometimes they ain't so smart.

On another note... I tried the bungees to see if they would close the gate... they would not. They can't pull the gate "over center"... Once I pushed the gate past the over center point, it would close.

So I am going to get a spring: http://www.gateshut.net/buy-your-gate-closer-here.html

 

[jwmorris]

I built a bump gate at our farm for 4 wheelers where I uses a broken garage door spring to bring it back to center.

It was the style spring that fits over a 1" or so shaft and is would around to provide tension to the cables, normally. Once it broke it made it down to the junk pile and was reused so an open gate bent it side to side and it's action would return the gate to center at rest.

 

[ns_in_tex]

On another note... I tried the bungees to see if they would close the gate... they would not. They can't pull the gate "over center"... Once I pushed the gate past the over center point, it would close.

So I am going to get a spring: Gate Closer, Farm Gate Latches, Automatic Gate Closers

If you are only opening your gate 90 degrees, you can make a set of hinges that will make the gate rise on the outside, & lean in, when opening to either direction. Then the weight of the gate will make it close without a spring. Not sure how fast you want it to close.

To do so, make your hinge pins adjustable and stagger them from plumb when the gate is closed, but plumb & level the gate when closed. The more you stagger the top hinge pin from the bottom, The more the gate raises & leans when open & the faster it closes when turned loose.