Quick release drill bit for down-hole drills

Abstract

A retainer device (10) is provided for retaining a drill bit (12) within a percussive drill assembly casing (2). The retainer device (10) includes a generally annular body (16) having a central axis and an inner circumferential shoulder portion (18) disposable within the casing (2) such that the body axis (17) is substantially collinear with a casing axis (2a). The shoulder (17) is deflectable between a first position (P1), where the shoulder (18) is contactable with the bit head (14) to retain the bit (12) within the retainer body (16), and a second position (P2). The second position (P2) is spaced radially outwardly from the first position such that the bit head (14) is displaceable through the body (16) in a direction along the casing axis (2a). Also, the retainer device (10) includes a spacer (24) that locates the retainer body (16) at a desired axial position within the casing (2) and a centralizer (26) that centers the body (16) about the casing axis (2a).

Dependencies are inferred from the claim text.