Main spring unwound on a BPO Dial

[b3tamax11]

Im currently working on stripping and rebuilding a BPO Dial out of my N2907 simplex set, and the main spring has come unwound. I've been following this diagram from the TCI Library for the dial, but I can't seem to figure out how to get the mainspring back together. Is this fixable?

[unbeldi]

I think, with determination, success will not be denied...   LOL.

This is perhaps similar in principle to this BTMC dial:





http://www.classicrotaryphones.com/forum/index.php?topic=8786.msg94454#msg94454

[b3tamax11]

Thanks for the help, I tried to rewind it, and I was nearly successful but the spring coil snapped. Guess im gonna start looking for a replacement dial, not touching another phone spring again though!

[Matilo Telephones]

A pity your spring broke. What happened? Was it rusty?

Perhaps you can find a replacement or adapt one from another model.

I Always wind these (BTMC dial) starting from the outside working my way in. It is actually easier that with for example the Ericsson bakelite dial, which has to be wound from the inside going out.

[b3tamax11]

The part that snapped is the small piece of coil that attaches to the dial frame. If I can bend another part of the coil over and get it to slide back in properly, it should work right?

[LarryInMichigan]

I have had that happen to several springs from dials and other things.  Those springs tend to be quite brittle.  With some skill and alot of patience, you might be able to bend the spring at the end without it breaking.  Appying heat may help, but I do not know.  The dial won't mind if the spring has been shortened a bit. 

Larry

[twocvbloke]

The part that snapped is the small piece of coil that attaches to the dial frame. If I can bend another part of the coil over and get it to slide back in properly, it should work right?

If you apply some heat to soften it, yes you can bend the spring to fit properly, just be careful to not overdo it though so it doesn't become too weak and break again...

[Kenton K]

I have done that before on old typewriter springs. You will need to heat it up. Enough to u temper the metal. Worth a shot. Good luck!

[Ktownphoneco]

Matt  ....   I have a replacement dial if your interested.     Missing the dial number card retainer spring and acetate window, and 2 terminal screws on the spring switch assembly on the back of the dial.

Cover the postage, and it's yours.     I'm in Ontario as well.

Jeff Lamb

[Ktownphoneco]

By the way, the British and Australian patent numbers on the finger stop, refer to improvements to the pulsing system on the dial.     The U.S. Patent number is "2,276,514".     The Canadian Patent number is :  "633,416".

Jeff

[Jack Ryan]

By the way, the British and Australian patent numbers on the finger stop, refer to improvements to the pulsing system on the dial.     The U.S. Patent number is "2,276,514".     The Canadian Patent number is :  "633,416".

Jeff

Probably a bit off thread and perhaps I should re-read the GEC patent but I do wonder how it was approved. A key claim is the impulse wheel follower or, so called, trigger that gives this type of dial its name - "trigger dial".

The trigger is very similar in operation to the trigger used in US Western Electric dials and also in BTMC dials (7000 series). The Western Electric trigger is based upon a Kellogg patent of Aug 13, 1912 - hence the patent date on US WE dials.

The Kellogg patent expired about 10 years before the trigger dial (Dial Auto No 12) was released.

Jack

[Ktownphoneco]

That's a valid observation Jack, and a good question.   I would imagine the inventor ( C.C. Puckette ) would have to prove or demonstrate, enough of an engineering difference as to it's design and function to make the patent "fly" so to speak.     I also wonder, if an inventor were able to win acceptance in one country's patent office, does that create a "rubber stamp" effect at the patent offices of other western nations.   I'd almost put money on the fact that if something wins patent approval in the U.S.A., it'll have no problem achieving the same results here in Canada.    But that's only my opinion, and doesn't make it a fact.

Jeff

[Jack Ryan]

I would imagine the inventor ( C.C. Puckette ) would have to prove or demonstrate, enough of an engineering difference as to it's design and function to make the patent "fly" so to speak.

That's true and very few patents, in my opinion, actually describe an invention. Most are, and are described as, "improvements" to someone else's invention. Even easier if the original patent has expired.

I also wonder, if an inventor were able to win acceptance in one country's patent office, does that create a "rubber stamp" effect at the patent offices of other western nations.   I'd almost put money on the fact that if something wins patent approval in the U.S.A., it'll have no problem achieving the same results here in Canada.    But that's only my opinion, and doesn't make it a fact.

Many such patents are identical to the original patent so there may be some rubber stamping going on. There would be cases though where there was already an existing patent very close to the application so I assume it would be rejected.

Larger companies, when applying for a patent in their own country would also apply, or as least issue a caveat, in other countries of interest. That way, clashes can be avoided or worked around.

Jack