Snap-on question.

[alton1911]

I have not been getting much time for hunting my favorite tools... the rusty kind, but I got a chance to clean this Snap-On 1” 12point 1/2” drive socket.
It’s stamped on one side patent applied for, and the part number SW-320,1/2 between the stamps there is a single number “9”.
What patent worthy difference were they trying to patent?






Thanks in advance,
alton1911

 

[Oldtuleguy]

Looks like a very early thin wall socket, I suspect it has something to do with that.