Grindle v. Welch

• Decision Date: 29 October 1956
• Docket Number: Civ. A. No. 34531.
• Citation: 146 F. Supp. 44
• Court: U.S. District Court — Northern District of California
• Parties: Eugene L. GRINDLE, Plaintiff, v. C. Martin WELCH, doing business as C. Martin Welch & Company, Defendant.

146 F. Supp. 44

Eugene L. GRINDLE, Plaintiff, v. C. Martin WELCH, doing business as C. Martin Welch & Company, Defendant.

Civ. A. No. 34531.

United States District Court N. D. California, S. D.

October 29, 1956.

Flehr & Swain, San Francisco, Cal., for plaintiff.

Naylor & Neal, San Francisco, Cal., for defendant.

EDWARD P. MURPHY, District Judge.

This is a suit for the declaration of invalidity of a patent, No. 2,534,644, and for certain relief incident to the invalidation of that patent, including damages and the assignment of the patent to the claimed true inventor. Jurisdiction arises under 28 U.S.C. § 2201.

The patent in question concerns a measuring device to determine the quantity of gasoline in the wing tanks of airplanes, known as a "dipstick." The dipstick is a liquid fuel column gauge, of a type long familiar. A patent issued as long ago as May 26, 1863, to one Hyde (No. 38,681) for a "cask gauge" described the essentials of the gauge as being a tube or cylinder "made of transparent glass, or its equivalent, and left open at either end", enclosed within the center of a square slitted rod "made of wood, metal, gutta-percha, or any other suitable material, so that either end of the rod shall be flush with the ends of the enclosed tube", and with suitable gauging scales marked on the four sides of the enclosing rod, each adapted to a particular type of cask, so that by observing the level of the fluid in the central measuring tube, the content of the cask or vessel could be ascertained. The operation of the device is the same as that used by children playing with straws. The tube is inserted vertically into the liquid to the bottom of the vessel. The operator then closes the top of the tube, either with his finger, or with some sort of valve, and withdraws the tube. The atmospheric pressure on the lower end of the tube, as it is lifted from the liquid, retains the liquid in the tube (up to its point of specific gravity). Hyde in his 1863 patent said:

"It is evident that the height of the column of liquid thus confined in the tube will indicate the depth of its previous immersion in the body of the fluid, and by comparing this column with a properly-graduated scale the quantity of liquid in any given cask or vessel can be accurately ascertained almost at a glance."

In 1922, another patent was issued to one Schmitt (No. 1,423,156) for essentially the same type of liquid fuel column gauge, differing only in the manner in which the central measuring tube is supported by the outer structure upon which the gradations are marked, and the slits in the outer structure through which the level of the liquid in the measuring tube may be observed.

This was the state of the prior art in liquid fuel column gauges. It is unnecessary to speculate upon whether the devices described in the Hyde and Schmitt patents were ever sufficiently "inventive" within the meaning of the patent laws to be patentable.

In 1948 the plaintiff in the instant case, Grindle, an engineer employed by Pan American Airways, developed at the request of his employer a dipstick, or liquid fuel column gauge, which would render more satisfactory service than those then in use. Grindle developed, apparently without knowing of the Hyde and Schmitt patents, a stick which consisted essentially of several measuring tubes, rather than one, joined in a single assembly, and made of plastic. He then contacted the defendant, Welch, at that time a representative for a plastics products firm, and handed him detailed drawings and a mock-up sample of the stick he had designed, for the purpose of securing price quotations from the defendant's employer. Defendant's employer returned the plans with the report that the particular shapes of plastic required to accommodate the plaintiff's design would be too costly to manufacture, and sent along several items of standard plastic tubing, called "extrusions", to inquire of plaintiff whether they would be adaptable to his needs. After some experimentation and consideration of various alternative expedients, plaintiff Grindle devised a dipstick incorporating standard plastic extrusion parts. In all essentials, the dipstick as finally submitted by plaintiff Grindle to defendant Welch and the latter's employer by means of a complete sketch and mock-up sample was the dipstick incorporated ultimately in Patent No. 2,534,644.

At the time of submission of the plans and mock-up of the dipstick to Welch, Grindle had no thought of patenting the stick, and no desire to keep the device secret for purposes of personal commercial exploitation or for any other purpose. He understood that because of the development work done by his employer, Pan American, through himself, the employer would receive a favorable purchase price quotation from the ultimate producer of the stick, whether that producer was to be Welch's employer or Welch himself. There was no disclosure by Grindle to Welch of any confidential nature which could lead to a recompensable breach of trust on the part of Welch.

It appears that during the period of final development of the dipstick, Welch had formed the plan to set himself up in the dipstick manufacturing business. He did so, and commenced to supply dipsticks in conformity with the plans drawn by Grindle. There were two minor variations in the stick as delivered and the stick as designed, and these variations (consisting of the substitution of radial grooves for square cut grooves in the wooden filler which spaced the two plastic measuring tubes inside the over-all square plastic housing tube, and of the substitution of plastic cement fill for the solid end plugs which Grindle had originally designed to shut off the ends of the square housing tube) were accepted by Grindle for Pan American because they had no appreciable effect on the functioning of the dipstick as designed by Grindle. They were minor details of construction or manufacture, "bugs", that every manufacturer encounters in the construction of his products, and that are eliminated by altering minor details which leave the product as a whole unaffected. The same is true for the protrusion of the tubes beyond the end pieces. Any skilled mechanic, or any person who has had some experience in working with plastics, could have accomplished the substitution of the cement mass for the end plugs, and the radial grooves for the square cut grooves, as well as the protrusion of the tubes beyond the end seals.

Welch commenced production of the sticks and made his first delivery to Pan American on August 12, 1948. That date...