Tail piece for an extendable drill bit assembly having a reduced head

摘要

An assembly includes a quick-release head, a tail piece and a flexible metal rod. The tail piece includes a shaft and a male coupler formed of a head, body, and flute. At least a portion of the male coupler head has a reduced outer dimension relative to an outer dimension of the body. When the male coupler is mounted in a second quick-release head or drill, a clearance space is provided between the reduced outer dimension portion and the second quick-release head or drill. During use, the assembly may undergo bending which results in significant forces applied in particular to the male coupler head. By providing the clearance space, these forces are predominantly shifted to the male coupler body, thereby reducing the likelihood that the male coupler head will shear from the remainder of the male coupler.

主权项

1. An assembly comprising:
a quick-release head having a wall defining a bore and a ball engaged with said wall and moveable relative thereto; a tail piece including a shaft portion, a male coupler portion provided at an end of said shaft portion, said male coupler portion including a head having a proximal end, a distal end and a length defined between said proximal end and said distal end, said head of said tail piece defining an outer dimension, a body having a proximal end and a distal end and a length defined between said proximal end of said body and said distal end of said body, said body defining an outer dimension, and a flute extending between said distal end of said head of said tail piece and said proximal end of said body, the head of said tail piece having a reduced outer dimension relative to said outer dimension of said body, the reduced outer dimension extends 360° around said head of said tail piece and is constant along the entire length of said head of said tail piece; and a flexible rod connected to said tail piece; wherein when said tail piece is seated within said bore of said quick-release head and said ball of said quick-release head is seated within said flute of said tail piece to prevent release of the tail piece from said quick-release head, a clearance space is provided between said head of said tail piece and said wall of said quick-release head along the entire length of said head of said tail piece, such that transfer of drive forces from an associated drill are predominantly shifted to the body.