(19)Fresh off Patent
(45) Week of Oct 19, 2026 No. 7 3,667 lapsed 70 listed
Tools & Hardware · expired at full term Oct 20, 2026

Folding knife with spring-loaded detent that propels blade open

A pocket folding knife with a pivoting blade and an assisted-opening detent. A spring-mounted detent bump engages a hole in the blade while closed and rests in an arcuate slot during rotation so that, once a threshold manual bias is applied, stored spring energy propels the blade fully open. Intended users are everyday knife buyers and outdoorsmen who want one-handed opening.

Sheet 1 of the patent drawings

(57) What the patent covered

This write-up was generated by AI from the patent's text and may contain mistakes, so check it against the original patent before relying on it.

The main independent claim covers a folding knife having a blade with an arcuate slot and a detent aperture, a spring applying bias perpendicular to the blade, and a detent bump on that spring which engages the aperture when closed and rides in the arcuate slot during rotation; the slot and a stop pin in the handle constrain blade travel and the detent design minimizes friction as the blade moves to the fully open position.

Distinguishing feature: A detent bump on a spring that engages a blade aperture when closed but then seats in an arcuate slot that follows the blade arc so the spring can release sufficient energy to carry the blade fully open while minimizing friction during rotation.

Novelty 3/5. Assisted-opening knives and detents were common; the specific combination of a detent bump that transitions from an aperture to an arcuate slot to reduce friction and store/release energy was a refinement on known assisted-open mechanisms.

Manufacturing

Stamped or laser-cut stainless blade with machined arcuate slot and detent aperture; formed spring or spring-steel detent assembly; machined or stamped handle scales/liners; assembly involves pivot-pin insertion, press-fit or threaded stop pin, and hand or machine final assembly.

Materials: Stainless steel blade, spring steel detent/spring, anodized aluminum or steel handle liners, brass or steel stop pin.

Manufacturability 4/5. Several stamped or machined metal parts plus a formed spring and pivot hardware; requires precision for slot/aperture alignment and stop-pin placement but uses common knife-making tooling.

Market demand

No demand check has been run for this patent. Likely search terms: assisted opening pocket knife, spring detent folding knife, blade with arcuate slot detent. The links in the sidebar open these searches.

Buyers: Everyday-carry users, outdoorsmen, handymen.

Before manufacturing

No related continuation or divisional patents in force were found. Design patents, trademarks and unrelated patents may still cover the product.

Claim focuses narrowly on a detent bump engaging a blade aperture then riding in an arcuate slot; manufacturing needs accurate sizing of slot, detent bump, spring force and stop-pin placement to function and to match claim language.

This patent has reached the end of its full term and cannot be revived. This page is a research lead, not legal advice. Obtain a freedom-to-operate opinion before manufacturing.

Claim 1, as granted

1. A folding knife, comprising: a handle; a blade coupled to the handle such that the blade is rotatable around a pivot point between a fully open position and a closed position, in which the blade is received in a space in the handle, the blade including an arcuate slot and a detent aperture; a spring positioned to apply a bias along an axis that lies perpendicular to a plane defined by the blade; and a detent bump coupled to the spring and configured to engage the detent aperture while the blade is in the closed position and to rest in the arcuate slot during a portion of the rotation between the closed position and the fully open position, including the fully open position, thereby minimizing friction between the detent bump and the blade.