Cutting by use of rotating axially moving tool – Processes – Bit detachable
Reexamination Certificate
2000-03-09
2001-07-10
Howell, Daniel W. (Department: 3722)
Cutting by use of rotating axially moving tool
Processes
Bit detachable
C254S13430R, C408S097000, C408S127000, C408S227000, C408S24100G
Reexamination Certificate
active
06257808
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to apparatus for and methods of drilling holes through generally inaccessible structural members concealed within hollow walls and pulling flexible lines through those holes.
2. Background Information
Flexible lines, such as electrical power wires or cables, telephone wires, coaxial video entertainment cables, fiber optic signal transmission lines, water lines (e.g., for a refrigerator's ice maker), etc., can be relatively easily positioned within the walls of a building or above a ceiling of the building if those lines are installed after framing, but before the walls or ceilings are completed. This approach is customary for new construction. Once the structure has been completed, however, adding, replacing, or moving lines within a hollow wall, in a restricted crawl space above a ceiling or beneath a floor is a much more difficult task.
In many remodeling or “old work” situations in single story residences a new line of some sort or another (e.g., a three conductor non-metallic sheathed electrical power cable) is run through an attic crawl space and down through a hollow wall to a service point (such as a point where an electrical outlet box is to be installed a foot or so above a floor, or a switch box located several feet above the floor). Ideally, to avoid damaging and replacing large portions of the wall surface, a job of this sort requires cutting or drilling a hole through the top plate of the wall, shoving the line through that hole and feeding it to a small access hole cut into the hollow wall. The necessary hole can be drilled from the attic and the line shoved down through the top plate only if there is adequate working clearance—e.g., if the vertical distance between the top plate and closest roof truss, roofing panel or other obstacle above it is great enough that a workman can put an electric hand drill into position to drill through the top plate. If the service point is located on an exterior wall, this approach commonly fails completely because the vertical free space between the top plate and the lowest overhead roof member is too small. Moreover, even when there is working clearance, there is always a chance for the worker to drill the hole through the top plate between two adjacent wall studs and then find that access hole had been cut between two other walls studs. This commonly requires a second trip into the attic crawl space to drill another hole.
It is known in the prior art to use a drill having a flexible shaft to drill the hole from below, then securing access to the hole from above and feeding the line through the hole. Again, working on an exterior wall can pose an insurmountable problem if there is so little clearance between the upper surface of the top plate and an overhead roof member that a worker can not reach the hole in order to feed the line through it. It is thus desirable to have a means whereby a worker can insert a tool through a small access hole in a hollow wall, drill a hole in a top plate of that wall, and fish a line through the drilled hole even if there is very little vertical clearance between the top plate and a roof member disposed above it. It will be understood to those skilled in the art that similar situations occur when cutting through a sill into a lower floor or a crawl space beneath a house.
A number of US patents are notable among prior art references in this area. These include:
U.S. Pat. No. 1,408,802, wherein Crocker et al. teach a flexible drill shaft turning within a flexible coaxial guide tube for use in drilling holes through a plurality of ceiling joists. Crocker et al. provide a collapsible and expandable guide device mounted behind the drill head. Their guide device is adapted to collapse when pushed through a hole in a joist, and to expand under the influence of bias springs when free of the joists. When in its expanded configuration, the guide device acts to space the drill bit away from the upper surface of a ceiling by some preset amount, thus ensuring that each of a plurality of holes is made at the same distance above the ceiling.
U.S. Pat. No. 2,958,349, wherein McNutt teaches the use of a drill bit rotated by a flexible shaft encased in a rigid guide tube. The drill bit is translated toward the work through a bushing affixed adjacent one end of the guide tube.
U.S. Pat. Nos. 3,611,549 and 3,697,188, wherein Pope discloses a flexible-shafted drilling apparatus for forming holes in and installing lines through structural members concealed within hollow walls. Pope teaches the use of a drill bit having a throughhole transverse to the axis. A line or a line leader of some sort can be fed through the throughhole to attach the line to the drill bit, which is then pulled back towards the drill operator by means of the flexible shaft. Pope also teaches the use of a separate tool for guiding his drill bit into cutting contact with the concealed structural member.
U.S. Pat. No. 5,395,188, wherein Bailey et al. teach the use of a curved, rigid guide for positioning a drill bit attached to flexible shaft so as to drill an upwardly angled hole from a starting point near a floor to a finishing point within a hollow wall. Bailey et al. teach the use of their drill guide to drill through the wall and the wall sill or sole plate.
BRIEF SUMMARY OF THE INVENTION
A preferred embodiment of the invention comprises a flexible guide tube having a work-engaging means adjacent a first end of the tube; a drill or other cutting tool adapted to be inserted into the second end of the tube and pushed through the tube into cutting engagement with an obstruction engaged by the engaging means; and a means for passing a line through both a throughhole cut by the cutting tool and the guide tube after the cutting tool has been withdrawn from the tube. in this embodiment the work-engaging element is adapted to hold the tubular guide in a fixed position against the torsional, or other, forces of a drill or other cutting tool being rotated by means of a flexible shaft disposed within the guide tube so as to cut the throughhole in the obstruction.
Another feature of a preferred embodiment of the invention is the combination of a flexible guide tube; a cutting tool driven by a flexible shaft to cut a throughhole through an obstruction, the cutting tool easily inserted into and removed from the guide tube; and a line-fishing apparatus easily inserted into and removed from the guide tube. It is a specific feature of some such embodiments that the line-fishing apparatus may comprise an end portion having a collapsed state in which it can pass through the guide tube and a throughhole in a top plate. This end portion may also have an expanded state in which it provides a visible target that can be readily engaged by tools operated by a worker in the space above the top plate who is prohibited from getting any closer than a few yards from the target.
It is an objective of some embodiments of the invention to provide a method of pulling a line through a throughhole in a portion of a structural member that is inaccessible to a worker on either side of the throughhole. It is a specific objective of these embodiments to provide a method of pulling a line through a throughhole in a top plate or a sole plate of a hollow wall having a nearest access hole more than an arm's length from the throughhole and having restricted worker access on a distal side of the top plate or sole plate. This includes cases in which the throughhole extends through the top plate at a location at which the vertical clearance from the top of the top plate to a roofing member is so small as to prohibit a worker from reaching the throughhole with his or her hand. This also includes cases in which the bottom, or distal, side of the sole plate is not accessible to a worker's hand—e.g., as occurs when one drills through the sole plate of a second floor wall into a space within a hollow wall on the first floor.
I
Howell Daniel W.
Kiewit David
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