Cutting by use of rotating axially moving tool – Means to drive tool
Reexamination Certificate
2001-08-28
2003-09-30
Howell, Daniel W. (Department: 3722)
Cutting by use of rotating axially moving tool
Means to drive tool
C408S199000, C408S222000, C470S198000
Reexamination Certificate
active
06626616
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to manually operated repair tool and, more particularly, to a tapping tool for repairing threads on PVC pipes and PVC pipe fittings.
2. Discussion of the Related Art
Fluid transfer systems such as those used for underground sprinklers, pools, and residential and commercial plumbing typically use PVC (poly vinyl chloride) pipes and fittings having internal and/or external threads for interconnecting the pipes and fittings according to a desired arrangement. During the continued use and repair of these systems it is not uncommon for the threads of the interconnecting PVC components to become damaged. When this happens, it is usually necessary to remove the damaged component and replace it with a new PVC pipe section and/or PVC fitting. In many cases, this involves a time consuming and costly repair procedure. Often, the cost of the labor to make the repair far exceeds the cost of the replacement parts.
For example, automatic sprinkler systems typically use PVC supply lines which branch out from a main supply and directional valve control to several zones. The supply lines extend underground, usually at a depth of between 12-18 inches below the ground surface. At select locations throughout each zone, sprinkler heads are interconnected to the supply line with the use of T-connectors, elbows or other fittings. A PVC riser pipe or other vertically extending PVC conduit structure is often used for delivering water from the supply line to the sprinkler head. The lower end of the riser pipe or other connecting component is provided with threads for attachment with threads on the underground PVC fitting. In some instances, the sprinkler head is positioned just below the ground surface, in a pop-up assembly, whereupon water pressure delivered to the sprinkler head causes telescopic extension of the pop-up assembly to elevate the sprinkler head when the zone is active. In other installations, the sprinkler head is secured on a fixed riser which threadably connects to the fitting on the underground supply line to position the sprinkler head at select distances relative to the ground surface and/or surrounding shrubs. Over time, the sprinkler heads and attached risers and/or other vertical extending structures are accidentally bumped, kicked and/or stepped on by playing children, yard maintenance people and others traveling across the lawn or through the shrubs. Moreover, sprinkler heads and attached risers are often damaged or broken by equipment such as lawn mowers, tractors, weed cutters and even automobiles which are accidentally driven into or over a sprinkler head. In other instances, the sprinkler head housing or riser is slowly rotated, over a length of time, due to the initial force of the water hammer against the sprinkler head when the zone is first activated, causing the threaded connection between the riser or sprinkler head and underground PVC fitting to become loosened. When the threaded connection between the riser and fitting is loosened, whether it be by the forces of water pressure or accidental contact by people or equipment, debris such as dirt and small pebbles enters between the threads on the end of the riser or sprinkler head housing and the fitting on the supply line. When the threaded connection is subsequently tightened, the threads on the PVC fittings become damaged by the dirt and other debris. Eventually, the damage to the threads becomes so severe that a threaded connection between the riser and fitting is no longer possible. This problem is usually noticed when the zone is activated and water gushes up from the ground where the damaged fitting is located.
Damage to the threads of the PVC fitting on the underground supply line may also result when a riser or other vertical extending structure is broken at or near the threaded connection. In attempting to remove the broken piece which remains threadably connected to the fitting, damage to the threads of the fitting often results, thereby preventing proper threaded attachment of a new riser pipe, sprinkler head housing or other component thereto.
Presently, there is no tool or other instrument available to repair the damaged threads of a PVC pipe or PVC fitting. Moreover, there is presently no tool or instrument available to repair the damaged threads of an underground PVC fitting (e.g. T-connector, elbow, etc.) such as that found in an underground sprinkler system. Thus, as explained above, when the threads of a PVC pipe section, fitting or other component become damaged, it is necessary to remove and replace the entire PVC component. In the example of an underground sprinkler system, when the threads of a T-connector, elbow or other underground PVC fitting become damaged, it is necessary to dig a large trench in order to gain access to the supply line and fitting. Next, it is necessary to cut the supply line at two locations, on opposite sides of the damaged fitting, in order to remove the damaged fitting from the underground system. A new fitting must then be attached to the supply line, usually with the use of glue and short pipe segments. A new riser or other sprinkler head device can then be threadably connected to the fitting prior to filling in the trench. This repair process proves to be time consuming and costly, particularly for the average homeowner who must pay a sprinkler repair service an hourly fee to complete the job.
Accordingly, in view of the foregoing problems associated with the damage to threaded connections of PVC pipes and PVC fittings, there remains an urgent need for a tool which is adapted to quickly and effectively repair the damaged threads without the need of costly and time consuming repairs.
SUMMARY OF THE INVENTION
The present invention is directed to a tapping tool for repairing damaged threads on PVC pipe and PVC pipe fittings (e.g. T-connectors, elbows, joints, etc.). The tapping tool includes an elongate rigid shaft having a proximal end and a distal end. A head fixed to the distal end is provided with a threaded tap formed of hardened steel for threaded engagement with the threads of the PVC pipe or PVC pipe fitting. Manual rotation of the shaft and head, using a handle fixed to the proximal end of the shaft, serves to advance and withdraw the threaded tap along the threads of the PVC pipe or fitting as the tap threads cut and reshape the damaged PVC threads, thereby restoring the threads of the PVC pipe or PVC pipe fitting to a uniform, functional condition.
REFERENCES:
patent: 614226 (1898-11-01), Huxley
patent: 1301802 (1919-04-01), Anderson
patent: 2053253 (1936-09-01), Dennis et al.
patent: 2110618 (1938-03-01), Baird
patent: 2465541 (1949-03-01), Kreshock
patent: 2661123 (1953-12-01), Guarino
patent: 5281059 (1994-01-01), Stuckle
patent: 6349624 (2002-02-01), Fahringer
patent: 00103 (1988-01-01), None
Downey PA Robert M.
Howell Daniel W.
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