Humpfreys "Safety" Double Snap Bolt for Breast Chains and Traces Pat'd 1888

Odd large snap bolt with a second bolt inside. Patent assigned to Humpfreys and Holloway. Forged Iron. 7 1/4" long. Marked "Holloway / Pat. Mar. 27, 1888 / Balto. Md." Intended for attaching breast chains and/or traces when hitching animals to farm implements. Humpfreys claims that in case the first bolt breaks or is impacted in such a way as to be temporarily opened the ring to which this snap bolt is attached will not be able to come loose due to the second bolt. Seems like a solution in search of a problem to me.