Pressure Bar Reduction Gearing

[Huw Eastwood]

Good find again- you're digging up some really good close-ups and hi-res pics.

It looks to me like the horizontal pressure bars fit into the central worm gear, with the worm screws being hidden from view on the vertical bars behind- the vertical bars are probably best described as 'drive bars', since they come direct from the central gearbox and serve only to drive the actual horizontal pressure bars themselves.

The horizontal pressure bars might be independent, but that would mean the central worm gear (the one that's visible), being in two halves, certainly not impossible but I'm not aware of that being normal gearing practise. It'd put a lot of additional strain on the teeth, and that must always have been a concern with these systems bearing in mind the immense forces and torque involved. I've only just had a quick look though so will come back and think it over a bit more. I can't make out a division down the centre of the worm gear from the photo, but that's not to say it's not there.

good find again though

[Doug MacQueen]

Diebold , Mosler and York all did that. I am sure others did too.

[wylk]

This one fascinates me because of the apparent emergency door on the left but it's way too small to crawl through. A vent perhaps (assuming it can be opened from the inside without needing the combination)?

[Huw Eastwood]

Diebold , Mosler and York all did that. I am sure others did too.

I like the look of the black Mosler door In the first pic doug. Also, noticed the additional stanchion bearings on both the vertical 'drive' bars supporting them immediately entering the top and bottom drive gearboxes. Not something I've noticed on many doors before. In fact the two circular housings appear to be just lightweight covers as opposed to the sturdy cylinders with bearings that we are used to seeing. Nice door has a lot of character to it.

[VaultDoors]

Good find again- you're digging up some really good close-ups and hi-res pics.

Th door appears to be from the Security Bank Building in Minneapolis, MN: http://flickrhivemind.net/Tags/secur...ng/Interesting

[wylk]

Th door appears to be from the Security Bank Building in Minneapolis, MN: http://flickrhivemind.net/Tags/secur...ng/Interesting

Los Angeles, actually; 500 South Spring Street.

[VaultDoors]

This Mosler vault door is selling on eBay at the moment and billed as 'circa 1880-90':



I asked the seller to remove the pressure gear drum lids and pressure hand wheel so I could see the insides:









For some reason where the horizontal and vertical bars meet the bevel gears don't appear to have all their teeth... Maybe it's just grease filling the gear valley's but it looks smooth to me. Can someone explain what's going on here?

[Doug MacQueen]

Looks pretty clear that it's not grease. Didn't need teeth all the way around so they didn't cut them in. That door looks alot like the nicely painted black one I posted. Doug

[Doug MacQueen]

Note the original teller stations. Don't see that very often.

[wylk]

I found a patent that might explain how larger doors' pressure systems work. See US patent 880,179 (Benjamin F. Tripp, 1908). Here are the figures of interest:

I'm having trouble seeing all of what goes on here but I believe this gearing is related to planetary gears and might be capable of the high gear ratios seen in larger doors. It also provides intersecting axes between the handwheel and bars, something you don't get with worm gears.