How to slow the closing of a rolling gate 2

[briceburg]

Some folks installed a rolling gate on a 7% grade. To open it, it rolls uphill. To close it, it rolls downhill.

The gate rolls along a 20' track between a brick house and the end-post of a fence along an alleyway. It rests against the fence end-post (6x6 pine) when closed, and against the house when all the way open. The track is anchored to a concrete driveway, and the gate is made of a 10' x 6' steel frame with cedar planks affixed to it. Needless to say; it is VERY heavy (300lbs?), hard to open, and very dangerous if left to close alone. If it were accidentally let go I imagine the impact would topple the end-post it rests against while closed, and end up in the alley.

I would like to minimize the damage done by the closing gate if let go. My idea is to slow the velocity of the gate -- but not sure what the best method is.

Some ideas are;

1. Counter weight - Fix an eye ring to the home, attach a rope to gate, run through ring and attach to some clock weights. Not sure if these will have enough slowing effect... and may allow the gate to be too easily opened? Could change with weather/rain?

2. A tension spring that works similarly to the above. Again, would it slow the gate in time?

3. A hydraulic fixture with a telescoping arm that when pulled on, will only pull out at a fixed, slow rate. This seems ideal but does anyone make them and what are they called?

Any suggestion are welcome!

 

[berkshire]

OOPS, I missed that one ,
Neglecting friction I get 36 LBs for the 7% grade with 120 LBs on the counterweight.
I used a metric calculator with the force on the gate being 161 Newtons.
B.E.

You are judged not by what you know, but by what you can do.

 

[dvd]

Granted that getting power to the gate opener could add expense, I think that a gate opener is not going to be that much more than buying all of the hardware and designing and fabricating the counterweight and components. Making this thing look like much more than a polished p.o.s. is going to be difficult. Also need to consider whether the gate opens with the counterweight or drifts shut with the counterweight. Operation in all weather conditions is also an issue. Plus,one still has to accelerate the counterweight and gate to get them moving. Recommendations for a counterweight would be to use a force gauge to decide on how much pull is required. Also use a steel box that can be filled with cement or steel punchings to get an accurate fill weight.

Regardless of how it is done there is more money and effort involved in making the gate close. Why not do the job right and level the gate?

 

[GregLocock]

The traditional blacksmith's method is to use a chain between the gate and a post, with a large weight located at the middle of the chain.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[berkshire]

Greg,
I have seen that system and totally forgot about it. If I remember right, the catenary effect of the chain increases the force on the gate as it gets closer to the closed position.
B.E.

You are judged not by what you know, but by what you can do.

 

[GregLocock]

Yes, it has almost the exact characteristic you'd like, while not using any fancy gear.

http://www.oldhouseonline.com/build-gate-doesnt-sag/

has a picture of the idea

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[kjoiner]

Hello,

As far as damping the final travel of the gate to prevent banging, you might look at a door check like this:

http://www.dictator.nl/engels/fredo.htm?http://www.dictator.nl/engels/doorchecks.htm

They make the door checks for swinging doors as well as sliding doors.

Kyle

 

[tbuelna]

I can just imagine briceburg getting out of his car, pushing the 300lb gate uphill to open it, then getting back into his car to drive thru before the gate rolls back downhill closed. And even if he manages to squeeze past the gate without getting hit by it, he will catch heck from the Mrs. for the noise the gate made when it slammed into the side of the house.

And briceburg, it will do no good to try and blame the posters on this forum for any problems that may occur with your gate system.

 

[Tmoose]

50 bucks too much?

http://www.gemplers.com/product/173161/Hand-Crank-Winch-Automatic-Brake-800-lb-Pulling-Capacity

actuation would be kind of slow, so a call for an electric gate opener would likely follow shortly thereafter.

http://www.chamberlain.com/garage-door-openers/chain-drives/model-hd200d

 

[MikeHalloran]

If one of the gate's wheels could be fitted with a crank, the crank's motion, and hence the gate's motion, could be damped by an ordinary telescopic shock absorber, attached between the crank throw and a fixed anchor point on the gate.


Mike Halloran
Pembroke Pines, FL, USA

 

[Ron]

Use rotational spring rollers on the gate. As it closes, the springs get tighter, thus offering resistance. Will help the opening process as well.

 

[MikeHalloran]

Wrap spring brakes, which I think Ron is talking about, are kind of finicky for outdoor use.

Mike Halloran
Pembroke Pines, FL, USA

 

[Ron]

Mike...I agree, outdoors might be a challenge. I was thinking along the lines of a garage door spring (similar, but much less resistance), attached to roller axle. Could be covered and greased for protection.

 

[berkshire]

Ron,
If you go that route, and I am not sure the OP will, Then a garage door wind up spring attached vertically to the wall of the house would work.
Put the cables one to the top of the gate and one to the bottom, and let the gate wind up the spring as it closes.
It may be possible to dispense with the top cable if the design of the garage counterbalance spring will allow it.
B.E.

You are judged not by what you know, but by what you can do.

 

[Ron]

Berkshire...that's a great idea! Could use existing garage door spring and axle setup.

 

[tbuelna]

A torsional garage door spring assembly would definitely provide close to the amount of travel needed, it has attachments at each end for connecting a cable, and it has provisions for setting the level of preload required. But these spring systems are usually something like 12ft long. Plus the system is designed for indoor use (the torsion spring is carbon steel) and must be protected from the weather.

It could definitely be made to work.