Pressure Bar Reduction Gearing

wylk · 2015-03-29T18:53:55+00:00

Pressure bars (pressure systems) are used on older vault doors and safe doors to pull the door into the frame (vestibule), ensuring a tight fit that in some cases was water-tight when new. I think it’s safe to say that bevel gears were often used to distribute the power from the hand wheel assembly to the ends of the bars, such as in these images: On some doors, no gearing at all was used and the bar was powered directly by hand: But on the bigger doors there was some sort of reduction gearing to amplify the force available. There is a video for example of the monster door at the Cleveland Federal Reserve being opened (see https://www.youtube.com/watch?v=5IqpCFTDo_M at around 2:20), and I think it was a program on the Discovery channel about the Fort Knox depository that included footage of the door being opened. In these cases the hand wheel goes through at least a dozen rotations while the pressure bars themselves operate perhaps 90 degrees. So there is some kind of reduction gearing at work. I thought I’d seen something long ago that suggested this was done using a worm gear arrangement (http://en.wikipedia.org/wiki/Worm_gear) but I can’t find anything about this aspect. I suppose planetary gears might also work (http://en.wikipedia.org/wiki/Planetary_gear) or helical gearing (http://en.wikipedia.org/wiki/Helical_gear#Helical). Does anybody have information on this aspect? Patents, drawings, imagery, recollections?

VaultDoors

MaxVaultage wrote
On massive doors like One King West or the Cleveland Fed, the surface area of the tapered plug closing into the jamb is immense- we’ve seen the paper clip imprint in the Cleveland Feds jamb, so one things for sure- with the tolerances of fit as tight as they are there’ll be scuff and abrasion marks everywhere if the pressure bar system has been continuously overcoming any binding points.

Speaking of door jamb damage…I noticed the One King West door jamb steps/rebates are dinged where the door pins line up:

This leads me to believe the door may have entered the jamb at a slight angle (not parallel to the jamb) and the door pins grazed the jamb. I suppose this could be avoided if the operator stops the door when it is just outside the jamb and pivots it slightly (using the pressure bars), then continues pushing the door straight in. Conversely, when the door opens the operator would pull the door straight out first then use the door handle to continue opening the door in an arc.

I reached out to Wylk on vault door open/close procedures and he shared his thoughts which I combined into the Vault Door Open Close Procedures document. I’ve never open/closed a vault door but this is my/our best guess at all that must occur in these transactions. As always, any corrections are gladly welcome.

[unknown]

VaultDoors

Notice on the One King West door the upper door pin collar is damaged (indentation). I’m guessing this is due to misalignment when the door was decompressed BEFORE attempting to retract the locking bolts:

This is perhaps why the Capital Grille door has door pin blocks instead of pin collars to ensure alignment and prevent broken/bent pins:

VaultDoors

After closer inspection I noticed a ding and deep scratch leading up the door pin collar which was obviously caused by the upper jamb pin. I imagine this happened as the result of someone losing control of the door when attempting to close it:

The upper jamb pin appears to be dinged up too:

We could devote an entire thread to vault door damage… 🙁smirk):

VaultDoors

Apparently, the upper jamb pin must be retracted before attempting to close the door so there must be three jamb pin positions:

Top jamb pin extended/Bottom jamb pin retracted - retracts bolts when door is closed
Both jamb pins retracted - when opening/closing door
Bottom jamb pin extended/Top jamb pin retracted - extends bolts after door is closed

VaultDoors

MaxVaultage wrote
I would have thought that whether the pressure bars were positioned behind or in front of the crane hinge would be determined by the actual diameter of the bars

I guess if you run out of space you could always ‘bubble over’ the pressure bar…

[unknown]

VaultDoors

Those last two pictures were of unidentified vaults so if anyone knows their identity, please share. I found another ‘bubble job’ on none other than the CFR’s emergency door. Glad they didn’t use that technique on the main door…🙁grin):

VaultDoors

Doug MacQueen wrote
Here are few examples of the Diebold.

Here’s a picture showing what appears to be individual horizontal pressure bars on a 4 point system:

Perhaps the vertical pressure bars are separate too?

[unknown]

Huw Eastwood

I’d forgotten about the channels on the emergency doors. Good point that, shows how tight that gap is even where the crane is a fair way off the door on large diameter pivots.

Doug MacQueen

Regarding damage, one of the dial knobs on the Fed door got clipped off while they were doing a video several years ago.

VaultDoors

VaultDoors wrote
I guess if you run out of space you could always ‘bubble over’ the pressure bar…

[ATTACH=CONFIG]13450[/ATTACH]

This emergency vault door and its main door are the only triple custody remote combination viewers I am aware of but their identity is still a mystery:

[unknown]

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 🙁y):

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

Doug MacQueen wrote
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.

[unknown]

VaultDoors

MaxVaultage wrote
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/securitybankbuilding/Interesting

[unknown]

wylk

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

Los Angeles, actually; 500 South Spring Street.

[unknown]

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.

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