TECHNICAL FIELD

The invention relates to a wood coring drill bit, more particularly, a wood coring drill bit having a plurality of slots radially therethrough positioned as points of a three-dimensional curve turning about the axis of rotation while moving parallel to the axis of rotation.

BACKGROUND

In the construction industry, power tools of various design have been used to excavate wood in walls, wall plates, floor assemblies and floor joists to facilitate the installation of mechanical systems, such as plumbing, electrical conduits, heating, venting, and air conditioning (HVAC) systems, sprinklers, chilled water systems, hot water heating systems, etc. One problem that occurs, misalignment of piping shafts through several levels of a building, is often a result of a tradesman evacuating/cutting wood from several floor assemblies at a time (stacking floor assemblies together before installation and making the holes for the piping shafts). After installation, pipe shafts that are misaligned require new holes, which results in multiple cuts in one or more of the several levels, thereby decreasing the structural integrity of the structure. Another problem is the use of power tools, such as chainsaws, sawsals, reciprocating saws, and similar power tool, which can be detrimental to the structural integrity of a building due to misuse and the inaccuracy of the tool. Such tools have been banned by Architects and Structural Engineers in many locations because of building codes, in particular in locations with more rigorous seismic codes and/or fire rating codes related to penetrations of wood assemblies.

The wood coring bit of a hole saw disclosed herein solves the above problems as well as providing code compliant holes, especially in view of new code requirements related to fire ratings and subsequent mechanical systems vertical and horizontal multi-level penetrations, e.g., a gap of half inch around the circumference of the penetrations through wood assemblies to facilitate the installation of firestop assemblies.

SUMMARY

In all aspects, a wood coring drill bits are described that have a cylindrical barrel defining an axis of rotation. The cylindrical barrel has a first end that is open and defines a plurality of cutting teeth and a second end defined by a hub having a bore therethrough comprising a connecting feature to connect to a drill motor for rotation therewith. The cylindrical barrel defines a plurality of slots radially therethrough positioned as points of a three-dimensional curve turning about the axis of rotation while moving parallel to the axis of rotation. In all embodiments, the three-dimensional curve may be a helix and the plurality of slots may be oval-shaped slots.

In all aspects, a plane coinciding with a first longitudinal axis of a first slot is also coincident with a longitudinal axis of a fourth slot. The plane coinciding with the first longitudinal axis of the first slot may also be coincident with a longitudinal axis of a seventh slot. From an end view, each of the plurality of slots is positioned at a center-to-center distance of 60° from an immediate neighboring slot relative to a longitudinal axis passing through each slot. In one embodiment, the plurality of slots is eight slots.

In all aspects, the plurality of cutting teeth is defined by two pairs of diametrically opposed gullets. From an end view, the two pairs of diametrically opposed gullets are positioned 90° apart, center-to-center, from one another about the axis of rotation. The plurality of slots has a first slot most proximate the first end of the cylindrical barrel and centrally positioned between immediately neighboring gullets from the two pairs of diametrically opposed gullets. Further, each of the plurality of slots is offset from a central longitudinal axis of each of the gullets, which are U-shaped.

The length of the cylindrical barrel is at least twelve inches (30.5 cm).

In another aspect, a set of wood coring drill bits comprises a plurality of the wood coring drill bits described herein, but with different diameters and/or lengths.

