GearHeads Forum

Hi Art

I started to build a simulation of a chronometer and the closest I could come at this time was try-6.gth.  I tried to attach it to an earlier message but couldn't because the .gth file is ~11MByte.  If you'd like to see it, I could email it directly to you.

Being a newbie to Gearotics, it took several tries to figure out getting the gears and spacings that I was after.  Your videos and some of the clock / escapement discussions on the forums were also a big help.

The way escapements are modeled in Gearotics, I imagine makes the coding more manageable.  In the clock world the escapement regulates the use of energy from a source e.g., a spring, weights rather than powering the clock.  Is there any chance in the future that a simulated clock mechanism could be powered by a spring or weight?

The chronometer I'd like to model contains things like a contrate wheel (aka, gear), fusee, maintaining spring within the fusee, chain barrel, remontoire, and more.  The escapement is one that is not modeled currently: a 15tooth crown wheel.

I have access to a E Howard Co. tower clock mechanism and that will be another simulation model that I will probably try this year.

Bill

Hi Bill:

>>If you'd like to see it, I could email it directly to you.

Even my email wont handle it, but Id like to see a snapshot of it if you get time..

>>Is there any chance in the future that a simulated clock mechanism could be powered by a spring or weight?

  Its possible. My conundrum is that Gearotics reason for existance was to make things as
easy as I could for people to make moving mechanisms that they otherwise might not even
attempt. In the end to keep complexity own I opted to make the driver power arrive
magically from the drive master.

  I may , however, at some point try to add a more user configurable simulation,
should I ever figure out how to do that.

  I am pleased that Gearotic can help in the complexity of what your doing,
its gratifying. When I start to do a module or escapement, its always built
on faith that "if you build it, they will use it. " , so far so good.

Ill keep your suggestion back of mind for next development season in GM..

Thx

Art

Hi Art

Attached are some screen captures of my Try-6 attempt to model an existing chronometer.  The escapement is one of your standard ones.  The real one uses a 15-tooth crown wheel that would be at right angle to the "contrate" wheel.

I don't have much time tonight to add much more description.  I used XNVIEW to perform the screen captures because the Snapshot and REC do not work properly on either of my Windows10 systems.

If I have time, I can try to take a video of the model later this week using my digital camera.

Bill

Looking good Bill, do you intend to actually build done of these?
If so, what kind of material?

Art

Bill, try zipping your gth file and attaching it.  I did a quick test and got about a 4:1 size reduction, although it was a very simple mechanism.

Kirk

Hi Art

I don't have plans to build the chronometer.  If built, the gears would be made of brass just like the original.

I am not like most of the users of Gearotics2.  My aim was to create reasonable simulations of clock mechanisms.

A matter of terminology::  I've been looking through the forums and realized that clock makers terms differ from those used in Gearotics.  I think elsewhere in the forums a writer mentioned some clock terminology (axles are called arbors, gears are called wheels, pinions are pinions but the teeth are referred to as leaves).


The escapement  I mentioned, "Crown wheel," is better known by it's earlier name of verge.  Really old time clocks used a verge/foliet combination.  The proper escapement for the my simulation model is verge/ balance wheel, where the balance wheel's timing is controlled by a spring.

On the wish lists for new Gearotics features was one for crown gears.  After looking at the old clock terms, a name for "Contrate Wheel" is probably exactly what the writer under the "Crown gear" was describing.  The gear is a short cylinder. The teeth appear to be pretty much straight cuts radiating from the center of the gear.  The mating pinion also appears to have straight cuts teeth.  The arbors of the contrate wheel and the pinion are at right angles to each other.

I read the note regarding zipping the .gth file.  I don't have the model with me but I'll look into it when I get home.

Bill

Hi Bill:

Yes, much of my terminology is mixed from clock making convention ( if there is such a thing. )

  I have looked at crowns in the request you mentioned, but I noticed even the examples posted
wouldnt mesh, as you say the cuts would have to originate from center, Im still considering my options there..

  Pinion gears "leaves" are usually in the context of epicycloidal tooth forms, and the leaves are usually puposely
smaller and more rounded that their wheels forms in order to keep any dust from jamming the works. Clocks
tend to have very loose gears in the drivers from escapement forward, and stronger tightly meshed spurs
in the train before the drive device , spring or weight.  Verge seems to be one of those terms that has slowly merged with
the actual pendulum mechanisms as well. The epicycloidics in Gearotic changed from the old versions of the software
as they were a more tightly meshing form derived from the math , but when writing gearotic I changed them to
a specification sent to me by a horologist. Its why the pinions now have rounded teeth.

  I continue to look into crown, verges or small bevel forms and will likely eventually add one or more, youll find
Im fairly eclectic in what I add or change, usually its when I find myself needing something that Ill end up
adding things to make it easier. Its why Gearotic exists, really ,as a place for me to put all the work I do
on any topic into general release in hopes it helps more than just me. This development season I havent added
much to gearotic itself , but as my laser did its first test fires under Auggie this week, I suspect by next development season
ll be back to adding toys to gearotic as I start to tie it all together into one large program like a swiss army knife,
which is my end game plan. I love clocks, widgets and moving mechanisms of all kinds, and really admire the work
people do, so Gearotic will probably never stop development, I just cant ever say if the next module is a escapement,
or a way to make a cool looking piece of art.

  Thanks for the post , it keeps me thinking in that line.. for example I must now go search Contrate.. never heard
of the term.

Art



  I find myself looking at wind driven objects with a certain facination lately .. so I may go that way.. Id need more 90 degree
tranmissions like crowns if I do end up in that direction.

Thx
Art




 



 

Hi Art

I thought I'd add some background on the chronometer simulation that I've been working on.

If you check out the following links to the Mystic Seaport site it's the entire story of John Harrison that really fascinated me.  John was "self-educated", a carpenter by trade who picked up clock making possibly by examining clocks of his day.  Solving the problem of longitude in the 1600's and 1700's was probably akin to us landing a man on the moon.  John Harrison spent his life improving the design of Grandfather clocks (long case clocks in clock makers parlance).  He took on the challenge of building a sea going clock.  What led him to the final solultion to the sea clock was his desire to improve a pocket watch. 

http://www.mysticseaport.org/ships-clocks-stars/

I couldn't decide which video was better because they are very similar:
https://www.facebook.com/mysticseaport/ ... 695884288/

https://www.facebook.com/mysticseaport/ ... 369314288/

The design for John Harrison's Timekeeper was actually published by the Board of Longitude.  The link below is a high resolution digital copy of the description of John's prize winning fourth Chronometer (simply known now as H4).  I downloaded and printed out the english portions of the document along with the mechanical drawings of the device.

http://cudl.lib.cam.ac.uk/view/PR-PBA-01740/6

I found the following link interesting.  Near the bottom of the webpage is a sketch of the mechanism:

http://www.frodsham.com/harrison-h4/

The verge (crown wheel) is shown and the shaft that drives it will lead you to the "contrate" wheel. The balance wheel is not shown. If you count the fusee arbor as the "1st" arbor, then the 2nd arbor actually drives the minute hand.  The third arbor has a gear that has teeth cut on the inside sort of like a planetary gear.  The fourth arbor powers the "seconds" hand.

Anyway, I plan to get a video to you soon.

Bill

Hi Art:

Last night, 2/15, I figured out how to make a video of my Try-6 simulation model.

As I mentioned in earlier posts, both of my computers now run Windows 10 & the REC and Snapshot functions do not work.  It's a Microsoft Windows 10 problem that does not necessarily show up on all platforms.

There are three free utilities that may help other users if they have problems with these Gearotics Functions due to Windows 10:

Screen snapshots:

XNVIEW has a screen capture mode that can be set to do multiple screen captures on an active window. I used this to make the .jpeg images in my earlier post.

An alternate to the REC function:

CamSudio is another open source program that allows screen captures of videos in an active window.  It can output in AVI, MP4, or Shockwave format.

Freemake video converter can be used for free and in a paid version allows fancier editing.  More importantly it can convert between different video formats and to change the resolutions of a captured video.

Try-6.gth Video

It took several tries for me to settle on the one attached to this post.  I hope the result is satisfactory.  The original video from CamStudio capture was ~6.8Mbyte.  I used Freemake to cut out some of the beginning and ending seconds & then convert it to a smaller size.  I decided not to record audio to decrease the file size.


Bill

Just as a matter of trivial interest the "Grandfather Clock" got its name from the song and up til then they were simply long case clocks.