Offset combination locks

Chubby

Whilst reading the thread about remote combinations I was reminded of the combination locks that used to be fitted which were not immediately behind the wheel. They were offset above, below, left or right and there was no way of knowing where the lock was. One thing you could guarantee was that the glass plate would be exactly where you didn’t want it!

Huw Eastwood

When you say ‘not immediately behind the wheel’ i’m guessing you’re referring to the dial, if so that’ll be direct drive and indirect drive comb locks.

Huw Eastwood

Just realised my post probably doesn’t make much sense as it reads, direct drive is of course dial spindle straight to the locks drive cam/wheel pack, indirect drive where the lock is offset and the drive cam/wheel pack indirectly driven via gear train.

Tom Gordon

RiemannHypothesis

Hello there!

Kromer manufactured such gear plates and I am also interested in those. In Remote viewers I think this is done on a very different scale, since the locks are at totally different positions than the remote viewer. Sometimes the locks are located near the floor. How did they manage to get the precision required for dialing when you have some gear in the way that will give you a bit of a shift, so that you dont hit the number on the dial you wanted to.

Any ideas?

Best regards

Maik

Huw Eastwood

Very nice Tom I bet they’re heck of a weight

Tom Gordon

Huw Eastwood wrote
Very nice Tom I bet they’re heck of a weight

I had to remove the floor and put in concrete in my office to take the weight of the safes -you are always welcome to escape down the M5 and have a look
Cheers
Tom

[unknown]

Huw Eastwood

Cheers Tom, a grand tour is on the to do list will get around to it eventually and will let you know cheers

Tom Gordon

Huw Eastwood wrote
Cheers Tom, a grand tour is on the to do list will get around to it eventually and will let you know cheers

I wouldn’t give anyone any warning if I was you - just go!
you never know, if the border patrols hear of your escape plan, then a high fence and emplacements could be erected on the border overnight. 😺

[unknown]

Doug MacQueen

I wasn’t aware of the risk of wall going up to keep the Welsh hordes from invading England, but it sounds like a good idea. Something like Hadrians wall to keep us Highland Scots out. Maik, that is good question about the gear lash losses. I would imagine that the pin on the lock drive wheel would be increased in size to account for the nearest whole number losses, once they were established. Of course increasing the tolerance of the fence to the wheel gating would also work, but I don’ t think it would considered an acceptable solution.

RiemannHypothesis

Hey Doug,

yeah you have several meters of spindle ways and several rectangular gears in some of the bigger doors (Cleveland for example). Yet, you as a user of the door have to be able to turn the dials as easily as possible. Even on my small door the spindle way is about 400mm and I have two sets of gears for each lock: One rectangular and one gear for the offset of the lock. If you take a big module for the gears, I guess you can reduce the play between them.
What are your thoughts on this?

Best regards

Maik

Doug MacQueen

Maik, it is not clear what your concern is, excessive play in the gearing or hard dialing due to the gear train? Either way I would first focus on making the gearing as smooth and free as possible, then worry about dialing losses. Increasing the drive pin size can be easily enlarged a bit with a fine chisel cut to spread the metal. Or metal added by soldering.

RiemannHypothesis

Hey Doug,

my concern is that the spindles have some weight, and in addition you have the gears and all that. So when I turn the dial on say the Cleveland door, I have to rotate several meters of spindle ways and gears. So some force is needed. And my question is just, how that is managed in a realistic way for the user. Of course good bearings and all that is a good start, but the precision for the parts is another story. Maybe now it is clear what I mean 🙂

Best regards

Maik

Doug MacQueen

Bearings can easily deal with the weight of the shafts and gears, so that would not be of concern. The only gearing I have any real experience with, is the geartrain of the time locks, where the high torque of the wound mainspring is reduced to the very light torque of the escape wheel. Friction occurs at the mating surfaces of the gears, so the more pairs of gears in the system, the higher the required torque to move the dial. However the better the gears are made, the lesser the friction. On a well made lock, the required torque to rotate the wheel pack with the dial is not very great, so a certain amount of increased effort in dial turning through a gear train would be acceptable. Keeping the complete rotation of the dial equal to a complete rotation of the drive wheel is a matter of matching the gear diameters. And as I mentioned before, fine tuning of the drive pin size can be done to match them up more closely if needed. Is this helping?

RiemannHypothesis

Hey Doug,

yeah the weight is not a problem for the bearings, thats right. The timelocks are tricky as well, but I think when you have strong springs in them, they should do the job. The only thing that bugs me is the human user who has to twist the dialer. When you have a 10mm spindle that is say 7 foot long (about 2,20m, and for the Cleveland door that is realistic, since the door alone is 5 foot thick) and then you take say 4 foot for the way down to the floor and all that, you have about 11 foot of spindle with 10mm diameter, and that runs you with about 2kg. Plus gears you get about 3kg i guess. Hmm now when I do the math, it actually doesnt look much. Okay I guess we can reduce the problem to friction and there you are right. High quality gears should make a comfortable turning possible. Any thoughts on this?

Cheers

Maik

T Davison

Maik
The answer to your question is gear train or a transmission style. The pressure angles of teeth means the angles at which one tooth presses against the other and can best be shown by looking at a pinion and rack type system. Of course pitch and number of teeth and diameter of the gears add or subtract for the fiction of this style of gear train.
The gearing formulas number 38 total , so to apply one to your question I would need a gear train to look at . Hope this helps so what. TJ

Doug MacQueen

Check out the “Keith Fenner Shaft Straightening With Heat” video on you tube. It shows how efficiently bearings can handle the weight and length of a large steel shaft. Note how little effort is required to spin it. TJ, I think you already have seen an example of the gear train in question with the pictures you posted. Here are a couple examples of dial extensions where more torque was needed. The upper left one is the turnknob that was clipped off the Fed door when a video was being shot. Note it’s diameter is larger than the standard S&G dial knob.

T Davison

The operating pressure angle is the distance at which a pair of gears operate.
standard pressure angle = standard pitch diameter.
3lbs of torque (standard pressure angle) to a(standard pitch diameter) 20 degree full-depth standard tooth by the number of teeth per gear ( standard 18 teeth) = smooth move movement of the gear train.

now on the bevel gearing and any other form of gearing has these formals for a no load movement of the system. Hope this helps, I been working in and around these system for over 30 yrs, still learning about what makes them move, work , and operate the way they do.

RiemannHypothesis

T J,

thanks for your replies. Yeah I guess the gear train is the issue we are looking at when it comes to remote viewers, since for ordinary doors you have a simple spindle and maybe some offset gears. Well it would be nice if somebody could make detailed pics of the interiors of a remote viewer. On the other hand we can take a look at the blue prints from @Vaultdoors . Maybe he can post them here again?

Doug,
thanks for the pics and I will take a look at Keiths video.

Cheers

Maik

Huw Eastwood

Maik, I can copy pages from the gears section of the ‘Advanced Machine Work’ bible if it’s any use to you.

Knowing that you’re a mathematician and that you’ve made your own I’m guessing it’s the bevel/mitre gears in the viewer unit you’re concerned about, rather than any basic spurs. I’ve cut small spurs over the years but have to admit large bevels are on a different level for me. Not only a lot harder to make but very difficult and critically sensitive to mesh-up, and in a minimal backlash/play application like these combination viewers they must have been a nightmare.

BTW, can’t believe no one else noticed the universal couplings in the viewer unit that TJ posted over on the other thread.

Theyre visible on the vertical shafts driving the combo indicators up to the viewer…..sorry Maik, yet more potential for backlash in the system, although they could probably only affect the numbers indicated in the viewer and not what’s on the main shafts being dialled to the locks…

Sorry mate, hope this makes some sense but is probably just adding extra…:s:

And, Chubby started this thread thinking of simple indirect drive locks, and here we are back on remote viewers and frame mounted whatever’s..