Shock Absorbers

Hydraulic door closer?

Opens easy, closes easy right up to the 'almost closed' position and then the damping cuts in. The good ones are easily adjusted for cut in point, amount of damping, etc.

Most hydraulic shocks damp when the piston is pushed in, but though I've never used them, I think I have run across reverse acting units.

Here are the mfrs I'm most familiar with:

A search for "hydraulic shocks" or "hydraulic dampers" on thomasnet.com will no doubt turn up more.

You can also use a linkage to allow an easy-to-find in-damping shock to work for you - but it's more complicated, slightly. Depending on the gate design, the "linkage" might be as simple as mounting the damper on the opposite side of the support.

Hmm- when I search on scissor gate, I get the sort of expanding mesh style gates, which would not make sense with banging down (at least all the ones I find open side to side). I'm envisioning a gate that opens from horizontal to straight up like a single-pole gate (barrier gate?) If the gate top pole extends beyond the pivot point, a compression shock on the top outside works the same as an extension shock on the top inside.

Get an adjustable rate shock absorber. Try the dirt racing guys - they can be set up for jounce or rebound.

Yes, that's 2nd choice.

Barrier gate or vertical swinging gate may be a better description. At any rate it's a 3' x 18' rectangle that weighs somewhere upward of 100 pounds crashing down on a bit of tire tread on a concrete block (it's not my design! Honest!).

And no overhang, and with the pivot in an enclosure. There's a linkage that I've dreamed up but if I can do it in one step I prefer that.

For a 200 pound 'door'?

Thanks Ned. I just found Ace Controls, so we're on the same page.

Make a damper. Use a hydraulic cylinder and a check valve with a drilled orifice in it. When the ram extends the fluid motion opens the check valve and the gate open easily. When the weight drops back some the valve closes and the pinhole bleeds the fluid off at a controlled rate. Gate comes down slowly.

I doubt if you'd bid on an RFP as vague as this.

A hydraulic or pneumatic damper is comprised of a cylinder, a valve that restricts flow, and perhaps a checkvalve that bypasses the restriction in one direction. All of these components are readily available.

Hi, Tim. I have a pneumatic cylinder with a check valve and an adjustable bleed valve that I was going to put on a metal band saw to control the down pressure, but never did and never will. I am sure the total piston movement is not enough for your gate, unless you can make a mechanical arm or cable to multiply the movement.

You are welcome to it. We are going to Aloha to my son's place for TG and will put it in the car for you if you want. If interested, email me at co snipped-for-privacy@yahoo.com and I can give you my cell phone number. We will be driving from Crooked River Ranch (Redmond-Terrebonne) either Mt. Hood or Santiam Pass, both tomorrow and Saturday.

Paul

I use these things daily... It really depends on how much you want to spend.

Not robust enough. The innards will blow apart in his application.

However, I stock 2" through 8" models if you want to try one...

They come in forward, reverse or forward and reverse control models.

Deschner is the best out there in the small item field. ...but they don't make a "pull style" unit. They only make plunger style units. However, if you can figure out how to use them, they have both "feed control" types as well as cushionair-type that act as a shock absorber.

I've got a bunch of sizes ranging from 1/2" to 6" in stock if you want to try one.

Semi-decent product... But I'm not sure they make a "pull style."

Never run across them in my field. Must be shock asbsorber-type only I guess just from a quick look at their site.

The best, and highest quality device I've run across is Control Line.

Costly, but they will make them totally custom for you to a degree. If you want, send me specs and I'll grab you one at my cost as an OEM that uses them often.

I'm guessing you probably don't want to spend too much on teh fix though. What's the budget for this part?

Regards, Joe Agro, Jr. (800) 871-5022

01.908.542.0244 Automatic / Pneumatic Drills: Spindle Drills: Tapping: Site: V8013-R

I built something similar to damp the slam of a heavy swinging-gate. I used the cylinder from a surplus foot-operated tire pump. It was fussy to tune, but it did the job for years. You could mount something like that on the end of the gate where it would have the most leverage.

Wayne

Btw...Deschner used to be one of my best customers. I built all the machines in their shop....Their OmniTurns that is.

Gunner

"Aren't cats Libertarian? They just want to be left alone. I think our dog is a Democrat, as he is always looking for a handout" Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls. Keyton

I just finished messing with the struts on my car. They mostly damped with the piston going out: though there was some damping force in both directions, it was much stronger when pulling them out.

This is as it should be: when going over a bump, the shock should be able to compress easily, so that the wheel goes up and the tire doesn't suffer too much; damping can be done on the way down, when the worst that can happen from too much damping is for the tire to lift off the road. So I expect that most automotive shocks are that way. A visit to a friendly local auto parts store would likely turn up a unit suitable for Tim's application. (If there is such a thing as a friendly local auto parts store near him -- one that'd let him browse their selection, rather than just demanding the make and model of the car it is to fit. That might take some finding.)

Its all about foot-pounds of torque and what length arm you fit to the damper.