IBM ITR/IBM 17 7 autowind question

[bruce linde]

just got this: IBM/ITR 17-7 - wall art

i'm used to the ka-thunk of my stromberg and gents master clocks, but this one just ticks along with no audible autowind sound... the motor definitely keeps it wound, and the gear attached to the motor seems to act as a built-in click to prevent the spring from just unwinding.

how often does it trigger? how do it work?

thx.

 

[bruce linde]

[sound of crickets]

 

[Jim Hartog]

Hello Bruce,

One of the crickets went to the IBM Clock Corner Reference Room and found something on the model 17. Rewind info is at the end. Link below.

https://www.ibm.com/ibm/history/exhibits/cc/pdf/cc_2407M172.pdf

I used to have one of these and I recall (Harold Bain told me) that the electromagnetic contact type rewind was updated to a little "motor" type? I could be wrong. The answer you seek may depend on the kind you have.

Jim

 

[bruce linde]

thanks, already downloaded that one... but neither the movement or pendulum on mine match what's on that page...

 

[John Lippold]

just got this: IBM/ITR 17-7 - wall art

I'm used to the ka-thunk of my stromberg and gents master clocks, but this one just ticks along with no audible autowind sound... the motor definitely keeps it wound, and the gear attached to the motor seems to act as a built-in click to prevent the spring from just unwinding.

how often does it trigger? how do it work?

thx.

Hi Bruce: The movement winding mechanism in your clock is not original to the clock. Someone has designed and installed a motor and gear arrangement to wind the movement. Your clock would have been originally wound via dual electromagnets, a ratchet pawl and spring arrangement. The original winding mechanism would have made that familiar clunk every minute plus and an additional 15 or so clunks at 59+ minutes when the master clock sent out its secondary clock correction pulses. In October of 1954 IBM announced a new motor driven winding mechanism which used a 50 cycle GE Telechron Synchronous Motor, ratchet pawl and spring design which was virtually silent plus would wind the clock back to the correct spring tension after a power outage. Using the 50 cycle motor would allow the mechanism to wind the main spring 72 minutes per hour until the clock was fully wound. I've attached a photo to show you what the IBM Synchronous Motor Winding Mechanism looked like.

John

 

[bruce linde]

i'm glad mine doesn't have the ka-thunk of my gents C7 or stromberg masters... it just ticks away. the guy who sold it to me said his dad had been a clock guy, so he probably did the conversion. he also said he's got a spare motor, which will be good to have.

i just scored another master clock off of craigslist (!) for another $60 (!)... a standard electric time, berkeley ca. it has a white case with gold trim and all auto-wind and stuff-needed-to-drive slave clocks. i will post another thread on that one if i can un-muck the escape wheel... its auto-wind is pretty quiet... there are two steel pawls reminiscent of a gents slave clock... but i'm getting ahead of myself.

thanks again for responding and posting the photo!