Tamper-resistant bicycle axle nut

摘要

A tamper-resistant fastener such as a nut for a bicycle has a smoothly rounded generally dome-shaped body and one or more recesses formed into the body. Each recess has a first and open ended portion which is bounded on radially inward side but not on the radially outward side, and a second and closed ended portion which is bounded on both the radially inward side and the radially outward side. Additionally, each recess can have an additional notch formed therein, the recess and notch together forming a major and minor recess. A wall which bounds the radially inward side of the recess decreases in radial distance from the central axis of the nut as the recess proceeds in the circumferential direction. A mating wrench has teeth that match the recesses and, if present, the notches.

主权项

1. A tamper-resistant bicycle axle nut comprising:
a generally dome-shaped body, the body having: a bottom surface; a top surface; a central axis; a central bore along the central axis, the central bore extending at least part way through the body from the bottom surface toward the top surface; and a curved outer peripheral wall extending circumferentially around the body, the curved outer peripheral wall having a recess therein; the recess increasing in radial depth as it extends circumferentially in a first direction around the body; the recess having: a first and open-ended portion that is not bounded on a radially outer side by the outer peripheral wall of the body; and a second and closed-ended portion in which the recess extends between the outer peripheral wall of the body and a curved inner wall, the closed-end portion being bounded on a radially inward side by the curved inner wall and bounded on a radially outward side by the curved outer wall to define a channel therebetween.