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US 5,193,951 AGranted
Wood-drilling bit
AssigneeVermont American Corporation
InventorThomas O. Schimke
Life of this patent
Estimating the term…
Abstract
A drill bit includes an elongated shaft with a threaded male end and a cutting head with an axial through-bore having female threads to receive the male end of said shaft in threaded engagement, and there is a bearing surface area between the shaft and the cutting head above the threaded portion which provides for proper alignment and reduced stresses.
Claims14
A drill bit, comprising:
- an elongated shaft defining a driving end, a central portion, an extended bearing portion forming a cylindrical bearing neck along the longitudinal axis of said shaft, said bearing neck having a smaller cross-sectional diameter than the cross-sectional diameter of the lowermost part of said central portion, so as to define an upper shoulder portion therebetween, and, projecting downward from said bearing neck, a threaded male end having a smaller cross-sectional diameter than the cross-sectional diameter of said bearing neck, so as to define a lower shoulder portion therebetween, said threaded male end having a pointed tip to serve as a pilot;
- and
- a cutting head defining an axially stepped through-bore comprising a threaded lower portion to receive said threaded male end of said elongated shaft in threaded engagement and an unthreaded upper sleeve portion which has the proper internal diameters and lengths to receive the bearing neck portion and lower shoulder portion of the shaft with a snug fit.
A drill bit, comprising:
- an elongated shaft defining a driving end, a central portion, an extended bearing portion forming a bearing neck along the longitudinal axis of said shaft, said bearing neck having a smaller cross-sectional diameter than the cross-sectional diameter of the lowermost part of said central portion, so as to define an upper shoulder portion therebetween, and, projecting downward from said bearing neck, a threaded male end having a smaller cross-sectional diameter than the cross-sectional diameter of said bearing neck, so as to define a lower shoulder portion therebetween, said threaded male end having a pointed tip to serve as a pilot;
- and
- a cutting head defining an axial through-bore having a threaded lower portion to receive said male end of said elongated shaft in threaded engagement and an unthreaded upper sleeve portion having a larger cross-sectional diameter than said threaded lower portion, so as to define a medial shoulder therebetween, wherein said unthreaded upper portion and medial shoulder are of the proper diameter and axial length to receive the bearing neck portion and lower shoulder portion of the shaft with a snug fit.
Dependencies are inferred from the claim text.