Learn me: What kind of hardware am I looking for?

I'm hoping this product exists and I just don't know what it's called.  I'm looking for a hinge that can lock in position at either end of a 90-degree range of motion - I'm intending for it to hold up a relatively light (only a pound or two) item that's between 2 and 3 feet long, but will be in the wind (15-20mph) so might need to able to withstand some additional force. Ideally it would also be relatively light. What kind of hinge am I looking for?

Take a look at folding table leg brackets. McMaster has those.

more application info might be necessary. I normally use McMaster-carr for something like that

So here's v1 of the concept. I got tired of getting close-passed all the time on my bike. State law in VA says motorists must give 3 feet to pass, so it's a visual indicator of what 3 feet is. The proof of concept has gone well, but I'd like something a little more permanent, and will either fold out of the way or retract for storage. My next iteration was going to be something like a toy lightsaber from Five Below mounted on a 90 degree hinge so I could swing it up out of the way.

I understand the idea, but I'd bet you're just going to end up with people messing with you more if you have something sticking out 3 feet.

In reply to szeis4cookie (Forum Supporter) :

Interesting,  What kind of bike is that ?  Tandem?  what do I see three sets of handle bars?

I'm 3 days in and about 25 miles with v1, my stress level has gone down a LOT. The number of marginal passes has gone down significantly, and I'm seeing people wait the extra few seconds for oncoming traffic to clear before making the pass. Definitely happy with how things are going so far, and I think it's working well enough that I want to iterate on the concept.

In reply to Indy - Guy :

It's an Xtracycle cargo bike. The two sets of handle bars on the rear rack are for the kids to hold on to - I can get both of them on the rear rack. All the kids' activities are within a 5 mile radius of home so it seemed really silly to drive short distances like that, and I get some extra training in besides.

Cool.  I didn't know those things existed.  Thanks.

Kinda pricey, but cool.

Pricey in isolation...but that is replacing a car for us. It'll pay for itself by the end of year 2

In reply to szeis4cookie (Forum Supporter) :

How about a Toggle Clamp.  It'll move through 90 degrees of motion, and have holding power in the "out" orientation.

Something like this:

Maybe this is better suited to your needs:

Make a chrome painted rubber medieval mace for the end of your arm to give people the hint. Edit: evidently, they make foam ones.

In reply to VolvoHeretic :

I have had some thoughts about adding something to the end to have some consequences for violating the space buffer, but haven't worked through how to do that without risking it bouncing back towards me or one of my kids...

Not exactly sure if it's sturdy enough but I used one of these to make a folding license plate bracket for a trailer: https://a.co/d/aQWBe7c

It only locks straight but there's enough friction in it that it doesn't really move around on its own when folded. There might be similar things that lock at both ends, I don't remember.

szeis4cookie (Forum Supporter) said:

In reply to VolvoHeretic :

I have had some thoughts about adding something to the end to have some consequences for violating the space buffer, but haven't worked through how to do that without risking it bouncing back towards me or one of my kids...

If you want to set yourself up for legal issues, that's the way to do it. Assclowns are going to assclown. The buffer will work for most, but you're going to get people that hit it on purpose because assclowns. Air horn and a camera would be my method. 

You might want to try a bicycle flag pointing straight up, and see if you get the same sort of respect with less risk of jerks treating you badly.

1/4 in x 6 ft Fiberglass Pole/Mounting Bracket, Bike Flag - 52WP75|52WP75 - Grainger

If you decide it doesn't work well enough, just mount it at a slight angle to the left.

If two kids on the back aren't enough to get some respect, a little flag pointing straight up isn't gonna do a thing. I've come to the conclusion that I need to take my space, as literally as I need to, in order to stay upright.