Quarter Inch Jack - Looking Fot Patent

[German_EE]

I am looking for the original patent on the quarter inch jack plug, as originally used on telephone equipment. I know that the design is very old and this means that there are some difficulties in finding the document I want, it may not have been scanned.

Please can someone with more experience of the patent system assist?

German_EE

[free_electron]

you mean the three or four ringed , long plug with the little 'ball' at the end ?

i believe those are called bantam plugs

google-fu  'bantam-plug patent'

http://www.google.com/patents/US4975087

[Pjotr]

http://www.google.com/patents/US4975087

That file is from 1990 

A 1-minute Google search on "telephone jack" brought up this": https://books.google.nl/books?id=EaVSbjsaBfMC&pg=PA51&dq=telephone+jack&hl=nl&sa=X&ei=c8cFVdymBsv2Up-rg4AB&ved=0CDEQ6AEwAg#v=onepage&q=telephone%20jack&f=false

But not the patent itself 

[Fraser]

More detail or picture needed as there are several generations of the 1/4" plug as has been stated.

I have used telephony patch cables with the smaller tip connection and of course most are familiar with the more common 1/4" headphone jack.

Please advise which version you are interested in.

Aurora

[calexanian]

Many of those original designs that got adsorbed by AT&T when they bought up the independent phone companies, and those of bell labs were just made directly public and were never patented as an agreement with the government. You will find lots of patents with improvements to the "phone plug and jack" as is its proper name, but most likely not find a true original patent that establishes the standard for that was in the public domain in the national phone system. Lots of interesting literature about the relationship Ma Bell had with the government and the public. Just try to find the earliest one you can. It will most likely be an "improved phone jack" type patent most likely from bell labs.

[Richard Crowley]

Following the history of telephone patents in the Google archives well into the mid 1800s, all the patents I found seem to take for-granted the existence of what we call the common 1/4 inch "phone plug".

[cosmicray]

The photo on this page (of a 1890's Viaduct 6-line switchboard) may be showing plug of this type.

http://www.telephonearchive.com/phones/switchboard-pbx/viaduct-wall-switchboard-phone.html

I saw another picture, reportedly dated 1879, of a similar type arrangement. Unless the telegraph system used them, it would be unlikely to be much earlier.