Shaffer v. Armer

• Decision Date: 11 August 1950
• Docket Number: No. 4015.,4015.
• Citation: 184 F.2d 303
• Parties: SHAFFER v. ARMER et al.
• Court: U.S. Court of Appeals — Tenth Circuit

184 F.2d 303 (1950)

SHAFFER v. ARMER et al.

No. 4015.

United States Court of Appeals Tenth Circuit.

August 11, 1950.

Wayne Coulson, Wichita, Kan. (Howard T. Fleeson, Homer V. Gooing, Paul R. Kitch and Dale M. Stucky, all of Wichita, Kan., on the brief), for appellant.

Lester B. Clark, Houston, Tex. (Henry V. Gott, Wichita, Kan., Andrews, Kurth, Campbell & Bradley, and Ray L. Smith, all of Houston, Tex., on the brief), for appellees.

Before PHILLIPS, Chief Judge, and MURRAH and PICKETT, Circuit Judges.

MURRAH, Circuit Judge.

This is an appeal from a judgment of the District Court of Kansas, holding invalid for lack of invention and for anticipation, appellant's Patent 2,211,173 for improvement in pipe coupling, referred to as a tool joint. In so holding, the trial court did not reach or decide appellant's claim that appellee Hughes Tool Company's "Counter Bore Weld Tool Joints" infringed his patent. On appeal, our first consideration is validity of the patent in view of the prior art. Or, otherwise stated, whether the trial court's judgment is clearly erroneous.

The tool joints involved here are used for bringing thirty-foot sections of drill pipe into threaded engagement to form a "drill string" or "drill stem" in the drilling of oil wells. When thus assembled on a rotary drilling rig, the drill stem serves as a drive shaft for turning a rotary bit and as a conduit to circulate "drilling mud" under pressure to the rotary bit at the bottom of the hole and back on the outside of the drill stem to the surface. When the rotary bit becomes worn, it is brought to the surface by pulling and breaking the drill pipe connections at every second or third joint. When a new bit is attached to the drill collar on the last section, it is returned by remaking the connections as the pipe is extended to the bottom of the hole.

The tool joints are ordinarily composed of two members, adapted to be threaded together by a coarse threaded connection. The opposite ends of the two members are internally tapered and threaded to be brought into threaded engagement with complementary externally tapered and threaded pipe to form a "bucked-on" threaded union of the drill pipe section and the tool joint member. The tool joint members customarily extend or overlay the drill pipe beyond the area of the threaded engagement to reinforce the tool joints against the expansive stress set up therein when the adjacent ends of the drill pipe are tightly screwed into them. The overlap or extension is usually of greater internal diameter than the external diameter of the drill pipe immediately adjacent the threaded area, so that the only engagement of the tool point and the pipe is along the threaded area. As a consequence, the expansive stress against the tool joint and the complementary compressive stress against the drill pipe abruptly terminate at the last threaded engagement, causing a concentration of the stress at the notch formed by the last engaged thread on the drill pipe. The twisting, bending, flexing and vibration of the pipe caused by rotating many hundred and sometimes several thousand feet of drill pipe in a hole larger than the pipe, many times results in costly failure or fracture of the drill stem at the last threaded engagement of the pipe and tool joint.

This problem has been the subject of considerable discussion in the industry and has provoked repeated efforts at solution, with varying degrees of success. As early as 1928, the industry was applying conventional or multiple bead metal weld on the drill pipe immediately adjacent the distal end of the tool joint. This metal band or weld prevented most washouts, but the space between the pipe and the tool joint where it overlapped the pipe, was not wide enough to allow the penetration of the weld to or near enough the last threaded engagement to relieve the concentration of the compressive stress at that point. And, although last thread failures were reduced, the problem was not solved. Moreover, the application of the multiple welded bead on the pipe tended to crystalize it and cause breakage at that point.

The Reed Roller Bit Company devised what is called its "Shrink-Grip" tool joint. It is only vaguely described in the record, but apparently embodies the principle of shrinking the tool joint shoulder over the pipe to reinforce it beyond the threaded engagement. The Pittsburgh special drill pipe, also directed to the last thread failure, provided a precisioned machined drill pipe and tool joint shoulder, designed to fit tightly together from the threaded area to the end of the tool joint shoulder, giving rigid support to the drill pipe immediately adjacent the last thread. While these devices tended to solve the problem, and enjoyed commercial success, they were said to be highly expensive and impractical.

It was in this setting and in the early part of 1936 that patentee Shaffer, an experienced machinist and rotary driller, conceived the idea, later embodied in his patent, of counterboring the unthreaded overlapping shoulder of the tool joint down to the last threaded engagement to provide a suitable space into which the metal weld would penetrate, reinforcing the last threaded engagement, and making the pipe and tool joint integral from the last threaded engagement to the end of the tool joint, thus eliminating the fracture-causing concentrated stress at the point of the last engaged thread.

About that time, the patentee prepared a paper on "Improved Conventional Type Tool Joint for All Makes of API Drill Pipe," explaining his proposed improvement. He attached a drawing depicting his conception, and comparing it with the conventional or multiple beaded weld. Another paper termed "Proof of Conception" (later lost and not produced in the trial or on the record), was prepared by the patentee to be signed by all parties to whom he should explain his improvement. In the Spring of 1936, he exhibited his conception and explained it to two representatives of the Hughes Tool Company, who signed his proof of conception and offered to make the tool joints in accordance with his specifications. Sometime thereafter, he caused several tool joints to be counterbored and welded in accordance with his specifications, and tested them for about a year on the end of a drill stem, experiencing no failures.

In February of 1938, Shaffer and the Reed Roller Bit Company entered into a contract, by the terms of which Reed was granted a nonexclusive license to the appellant's improvement, and began the manufacture and sale of the improved tool joint. On June 6, 1938 Shaffer applied for a patent. After prolonged proceedings in the patent office, during which a total of seventeen claims were urged, and after three complete rejections, the patent was granted with three claims, the first of which is typical and fairly illustrative: "In a pipe joint comprising complementary tapered pin and box members in tight threaded engagement with each other, whereby the box member exerts a compressive stress on said pin member along the zone of such threaded engagement, a ring of weld metal surrounding and joined to said pin and box members and extending from...