Help with ID please

Greetings! Found this in Grandpas garage. Unable to identify on Google images. The stamp on side (both pieces reads, “PAT 215771”) and I am unable to find old patent that matches. Thoughts? Grateful for your help!
Kristi
Washington State

 

That's really hard to see, Kristi. First, we're going to post as Full Image so your photograph is larger. Next, I'm going to suggest you re-photograph both pieces side by side on a plain background and repost. If you're unable to do that, please tell us what you think it is. (A tool?) What you think it's made of. (Metal?) And what are the dimensions?

Debora

 

The pieces weight 20ounces each. The garage had various collections of wagon team tack, agricultural tools, and cabinetry tools. I’m stumped.
I appreciate all suggestions. Thank you!

 

I think there is a number missing in your patent. Check this:

https://patents.google.com/patent/US2157713A/en

 

Here's the illustration of the coupling (look at the third from the bottom and the bottom piece):

 

Amazing!!!! Thank you so much!

 

Learn something new everyday! Used in oil wells.

 

Sucker rod couplings! Who even knew such things existed?

Debora