Gamble-Skogmo, Inc. v. Paul E. Hawkinson Co.

98 F.2d 37, 1938 U.S. App. LEXIS 3140
CourtCourt of Appeals for the Eighth Circuit
DecidedJuly 13, 1938
DocketNo. 11148
StatusPublished
Cited by8 cases

This text of 98 F.2d 37 (Gamble-Skogmo, Inc. v. Paul E. Hawkinson Co.) is published on Counsel Stack Legal Research, covering Court of Appeals for the Eighth Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Gamble-Skogmo, Inc. v. Paul E. Hawkinson Co., 98 F.2d 37, 1938 U.S. App. LEXIS 3140 (8th Cir. 1938).

Opinion

THOMAS, Circuit Judge.

The appellees brought suit in the district court charging appellants with infringement of the Hawkinson patents No. 1,917,261 and No. 1,917,262. The defenses are invalidity and no infringement. There was a decree for the plaintiffs and the defendants appeal.

Both patents pertain to the art of retreading worn automobile tire casings. A tire casing is the outer part of the tire within which the inner tube is placed. It is made of fabric covered with vulcanized rubber. The casing consists of three parts: (1) The bead rims, or enlarged parts of the tire usually containing metal cables, which are held by the wheel rim; (2) the side walls,- or the parts between the bead and the tread; and (3) the tread, consisting of the thickened portion of the tire which bears upon the road. That part of the outer surface of the tire which directly engages the road is called the crown. The somewhat angular portions at the margins of. the crown aré called shoulders.

In use the most rapid wear is upon the crown of the tire. The rubber upon this surface wears off before the rest of the tire is worn out. If the rubber at this point can be renewed without injuring the underlying fabric and the sidewalls, the life of the tire -can be materially prolonged. The art of replacing the worn out rubber on the crown has grown and developed with the development of the automobile tire business.

In general the process of renewing the worn out rubber has always been (1) to prepare the crown by removing the old rubber or by cleaning and roughing it, (2) to cement a strip of raw or unvulcanized rubber on the clean surface, and (3) to “cure” or vulcanize the new rubber in the desired shape and to secure it to the body of the tire by the application of heat and pressure. For the accomplishment of this process a metal mold or matrix is used, with the necessary auxiliary facilities to supply heat and pressure. These essentials of the process and various devices for retreading tires were in use when Hawkinson entered the field.

The Hawkinson patents were both issued July 11, .1933. No. 1,917,261 is for a method or process for retreading tires, and No. 1,917,262 covers a device or apparatus for use in retreading. Only claim 6 of the method patent and claims 4, 5, 6, 9 and 10 of the apparatus patent are involved in this suit. Claim 6 of the method patent reads:

“The method of treading tire casings, which comprises applying a tread material to the crown of the casing intermediate the shoulders thereof, in placing the casing within and permitting expansion of the same against an annular matrix that engages only the newly applied crown tread and adjacent shoulders of the casing, whereby to confine the newly applied tread material between the shoulders when under pressure and in a flowing condition, in applying internal expanding pressure to the casing to expand the same against the matrix, and applying heat to the matrix.”

Claim 4 of the apparatus patent is typical. It reads:

“A tire treading device consisting of an integral cylinder-like mold having continuous tread material confining flanges inwardly projecting from the marginal portions of said mold, said flanges being of such construction and extent as to make only line contact with laterally spaced shoulder portions of a tire and support the mold over the crown portion and out of contact with side wall portions of the tire, and heating means extending circumferentially of the mold.”

Qaim 5 adds to the combination thus described, “means to vent the mold between the tread confining portions thereof;” claim 6 further describes the mold as “substantially flat in cross section and composed of relatively light flexible material such that it will be brought into true round by circumferential expanding pressure of a tire placed therein;” and claims 9 and 10 describe combinations of the same features.

In the specifications of the patent it is said the important objects of the invention are to provide a light-weight annular tire treading mold that can be easily handled, that will heat and cool rapidly, that is resilient so that it can be brought into true round by the circumferential expanding pressure of a tire within, and a flexible heating means extending circumferentially and which will flex with the mold.

As the advantages of the Hawkinson patents counsel enumerate in the briefs [39]*39certain economies, together with the added advantage that the tire is retreaded without subjecting the sidewalls to heat. It is also said that certain benefits accrue from curing the new rubber while the crown is in a flattened position rather than in a mold which is curved to conform to the normal shape of the crown. The invention claimed for both patents is stated by counsel as follows :

“Hawkinson had an entirely new conception. He realized that the heat must positively be kept away from the side walls of the tire. * * * He conceived of a method in which the shoulders and portions of the old tread would be left on the tire and the newly added tread material would be confined between 'the shoulders and on the crown. * * * The tire is engaged by the hot mold only on the top of each thick shoulder * * *. The heat is thus very efficiently used and is kept away from the side walls.”

The mold, as illustrated in both patents and as exhibited to the court, is an unbroken ring formed by brazing together the ends of a band of light flexible metal approximately %2 of an inch thick. The “heating means extending circumferentially of the mold” is a copper coil through which live steam circulates.

The necessary pressure of the mold upon the new rubber during the vulcanizing process is obtained by using a mold whose inside circumference is slightly smaller than the outside of the tire. By spreading the bead the circumference of the tire can be contracted, and it can then be slipped into the mold and there allowed to expand. The inner tube is then inflated to increase the expanding pressure.

The accused device consists of a split mold which is forcibly drawn together to contract it against the tire and thus provide pressure. When the ends of the split mold-are drawn together they are fastened with bolts, and the mold when thus in operation forms a completed circle. The mold is not cylinder-like or substantially flat but has a curved cross section to fit the rounded surface of the tire. It is made of relatively heavy steel plate % to % inch thick. The mold is provided with marginal flanges which do not extend down upon the sidewalls of the tire. It has no heating means extending around it on the outside comparable to the steam coils of the patented device, but is heated by electricity passed through the body of the mold.

We shall first consider the one issue which involves the validity and infringement of both patents. It is the claim of plaintiffs that the exemplification of inventive genius lies in the protection of the sidewalls of the tire from injury by heat in the process of vulcanizing the new rubber on the crown; and the charge that in this particular the defendants infringe both patents. The determination of this problem requires a review of the prior art.

The early vulcanizing was done by placing the entire tire and mold in a steam filled kettle. Jones (patent No. 1,467,761, 1923, application 1921) taught that heat must be confined to the new tread and that the interior of the tire and the sides beyond the tread must be “protected against the action of the vulcanizing heat.” In 1932 he was issued a patent (No. 1,852,886) for an improvement upon his original device.

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Bluebook (online)
98 F.2d 37, 1938 U.S. App. LEXIS 3140, Counsel Stack Legal Research, https://law.counselstack.com/opinion/gamble-skogmo-inc-v-paul-e-hawkinson-co-ca8-1938.