(OT) How did those old gas station bells work? (2023 Update)

It is just a firm hose (that will go back to its original shape after a car has driven over it) closed at one end and with a pressure activated switch on the other end. When a car drives over the hose, the air in the hose is compressed and the switch activates. The switch closes a circuit wired to the bell and a power supply.

Such pressure sensitive switches are used for other purposes as well, e.g. to control the inlet of water in a washing machine. They are commonly available.

The air pressure spike probably rang the bell directly, no electricity required. It was no doubt mechanically clever.

Traffic monitors are similar, but they are electronic.

Den torsdag den 21. september 2017 kl. 19.46.50 UTC+2 skrev snipped-for-privacy@tubes.com:

Mrpete222 aka tubalcain youtubes favorite granddad and shop teacher will tell you

Lasse Langwadt Christensen wrote on 9/21/2017 2:17 PM:

It has to have electrical power because the pressure change of a tire compressing a few inches of a hose that many feet long would be pretty small. The work produced would be far too small to ring the bell hard enough to hear it.

Oh that's funny! No one seems able to conceive that something might work without electricity. A car passing over the hose displaces plenty of air to launch a little piston against the bell. No switches required.

Jeroen Belleman (really!)

His videos are interesting, I'm not a machinist but he explains thing very well.

Cheers

they obviously did it with electricity because doing it with air would just work too good ;)

Den fredag den 22. september 2017 kl. 00.22.59 UTC+2 skrev Martin Riddle:

he has a life time of experience as a shop teacher ;)

I examined them when I was a kid and the ones I saw had no electricity, just a plunger that struck the bell when a vehicle squashed the hose. That's not to say that some did not use electricity but the ones I saw did not. What got me looking at it was when the power was off in the whole town and the bell still rang.

A simple air pressure switch. stem on the hose, or drive over it, and the volume of the hose is reduced, so the pressure increases, closing the switch that powered the "clapper" on the bell. Dirt simple.

You got it right

Every service bell I've run into, at every shop I've worked at, was an electric bell switched by the "air pulse" from the squeazed hose. Most were "miltons" -a few "tru-flates",. Every one of them had to be plugged in to the electrical supply - we unplugged them at night to prevent them from triggering the alarm system if someone drove over them after hours.

Had to have a fat hose.

While it's possible that some worked without electricity, I had mentioned this to a friend who used to work as a mechanic in several service stations. He's about 15 years younger than I am, but he said that he worked at one station that still had one of those bells in the late 70s or early 80s. He said it quit working, so his boss told him to try to fix it. After checking the hose, he opened it, and found a bell with a transformer, which he said looks like a common home type doorbell transformer.

At the end of the hose inlet, he said there was a diaphram connected to an electrical switch. The diaphram was torn, so his boss ordered a replacement and that fixed it.

I'm guessing that the transformer is either 16V or 24V like most household doorbells.

He also told me that the hose they used on the lot, was just a standard air compressor hose with the outside end plugged.

Not really.

Might have run off the air compressor which remains pressurized for some time after a power failure. It's hard to imagine such a small change in volume producing enough work to ring a bell.

In the 4 stations I worked at as a gopher in the late '60s, NONE of them had electric bells.

And NO, the hose wasn't full of air. It was full of oil.

The striker would hit the bell going up when someone rolled over the hose, and again on the way down when they rolled off the hose.

Hence the da-ding every time.

Actually some of the earliest patents going back to 1892 Electrical Hose Signaling Apparatus used a battery for power. Were there even gas stations in 1892? I'm pretty sure there weren't many, it must have been used for something else at the time.

Maybe ask the NASA tranny...that old fool takes 10 minutes to explain 5 seconds of material.