Invalidity dossier
US 222441
Improvement in separable buttons or studs
Added 9/23/2026, 4:55:38 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US 222,441
Title: Improvement in Separable Buttons or Studs
Inventor: Frank P. Barney, of Norton, County of Bristol, Massachusetts
Patent Date: December 9, 1879
Application Filed: September 13, 1879
Publication Date: December 9, 1879
Legal Status: Expired – Lifetime (anticipated expiration December 9, 1896)
Purpose:
The invention improves separable buttons or studs—fasteners whose two sections lock together by a locking-lever under spring action. It is expressly a follow-on to the inventor's earlier Letters Patent No. 217,318, dated July 8, 1879, and refines the locking mechanism disclosed there.
Plain-Language Scope:
Five claims are presented:
- A bearing plate (B) on section A, having an anchor-shaped offset (b) and projecting abutments (b²), to serve as a bearing for the locking devices, a seat for the post, and an abutment for the actuating spring.
- The combination of section A, plate B, post C, and a locking-anchor (D) with a spring (d²) coiled around its push-rod.
- The same combination, with the spring's outer end rigidly connected to the push-rod and its inner/free end bearing on abutments (b²), together with section E and sleeve F.
- The combination, with a serrated or toothed push-rod end, of a hollow cylinder surrounding that end—permitting the soft fine-metal cylinder to be swaged into the rod's serrations without soldering or brazing.
- The push-rod locking-device combination further specified (claim text is truncated in the excerpt).
The specification also emphasizes an elliptical or double-convex post C, preferred for small studs due to strength relative to space occupied, and a sleeve F with recesses accommodating the anchor's side arms and the push-rod.
Source: https://patents.google.com/patent/[US222441](/patent/US222441)/en
What the excerpt does not establish:
The supplied text contains no assignee information, no litigation or ownership-transfer history, no validity analysis, and no substantive prior-art citations beyond the inventor's own earlier patent. Claim 5's full text is incomplete. The "Expired – Lifetime" status is stated by the source as an assumption, not a legal conclusion.
Generated 10/1/2026, 9:44:01 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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