Turning – Portable lathe for pipe turning
Reexamination Certificate
2000-05-12
2002-07-02
Tsai, Henry (Department: 3722)
Turning
Portable lathe for pipe turning
C128S126100, C128S126100
Reexamination Certificate
active
06412376
ABSTRACT:
FIELD OF THE INVENTION
1. Field of the Invention
This invention relates to tools for underground, in-place and otherwise on-site cutting, grinding, honing and otherwise smooth-surfacing of broken or rough ends of PVC pipe for fitting such connectors as T-joints, end unions and angled couplings.
BACKGROUND OF THE INVENTION
2. Relation to Prior Art
There are known cutters, grinders and hones for finishing ends of metallic pipe, some of which can be used on PVC pipe, but none particularly for PVC pipe with the low weight, convenience and low cost of this invention.
Examples of a known related but different pipe-end cutters and grinders are described in the following patent documents. U.S. Pat. No. 4,952,103, issued to Bresin on Aug. 28, 1990, described a nozzle-tube resurfacing tool that was limited to having an end of an alignment bit inserted in the tube for alignment of a tube-end cutter. U.S. Pat. No. 4,934,109, issued to Allred on Jun. 19, 1990, described a pipe-end grinder support having a body portion with three legs extending to an internal periphery of a pipe. U.S. Pat. No. 4,620,823, issued to Hillestad on Nov. 4, 1986, described a portable tube-milling tool having a collet on a tapered shaft in a tube to hold it steady and prevent its rotation while being cut with an end-cutting tool. U.S. Pat. No. 3,870,429, issued to Lomax et al on Mar. 11, 1975, described a pipe-end trimming method limited to extending a cutting edge on a pilot from a cutting tool inside of a pipe while the cutting tool and the cutting edge on the pilot are being rotated to cut an end of the pipe with the cutting edge on the pilot. U.S. Pat. No. 3,142,139, issued to Mangum on Jul. 28, 1964, described an oil-well drill-collar-facing tool which was threaded tightly onto tapered threads of drill collar for anchoring an end-mill cutter to fine-cut an annular end of the drill collar precisely orthogonal to an axis of the tapered threads. U.S. Pat. No. 2,811,903, issued to Harmes on Nov. 5, 1957, described a facing tool having a frame mounted rigidly to an outside of a work piece having a cutting edge was rotated in the frame to cut a face of the work piece. U.S. Pat. No. 2,414,731, issued to Forbes, Jr. on Jan. 21, 1947, described an elongate hub positioned rigidly inside of a pipe with three legs tightened against an internal periphery of the pipe while a grinder on a radial extension from the hub was rotated in cutting contact with an annular end of the pipe.
SUMMARY OF THE INVENTION
Objects of patentable novelty and utility taught by this invention are to provide a PVC-pipe-end smooth-surfacer which can be used quickly, conveniently and inexpensively to cut and grind broken and jagged ends of PVC pipe for effective pipe fittings.
This invention accomplishes these and other objectives with a PVC-pipe-end smooth-surfacer having a reamer cylinder sized and shaped to fit slidably on an outside periphery of a PVC pipe proximate a pipe end to be cut with a cutting wheel rotatable in a cylinder-end bearing while a cutter shaft on the cutter wheel is being rotated with a cutting element of the cutting wheel in cutting contact with the pipe end. A shaft keeper on the cutter shaft assures limited travel of the cutter shaft through the cylinder-end bearing. An insertion spring on the cutter shaft positions the cutting wheel in predetermined pressure against the pipe end. A reamer-cylinder end can have chip-removal apertures for discharge of pipe-end cuttings. The reamer cylinder can have one or more internal graspers which center and fix the reamer cylinder non-rotationally and yet removably on the external periphery of the PVC pipe. Low-friction bearings can be provided for rotation of the cutter shaft in the cylinder-end bearing. The cutter shaft can be structured for rotation by hand or motorized tooling. The PVC-pipe-end smooth-surfacer can be structured in sizes to cut PVC pipe ranging from about three-fourths-to-twelve-inches in diameter.
REFERENCES:
patent: 3875831 (1975-04-01), Beaulyoe
patent: 5197362 (1993-03-01), Birkestrand
patent: 5351587 (1994-10-01), Griffin
patent: 5711197 (1998-01-01), Ohmi et al.
patent: 5743539 (1998-04-01), VanderPol et al.
Johnson Merrill N.
Tsai Henry
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