Inpro, Inc. v. AW Chesterton Co., Inc.

657 F. Supp. 935, 2 U.S.P.Q. 2d (BNA) 1597, 1987 U.S. Dist. LEXIS 2801
CourtDistrict Court, N.D. Illinois
DecidedMarch 30, 1987
Docket85 C 8477
StatusPublished
Cited by1 cases

This text of 657 F. Supp. 935 (Inpro, Inc. v. AW Chesterton Co., Inc.) is published on Counsel Stack Legal Research, covering District Court, N.D. Illinois primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Inpro, Inc. v. AW Chesterton Co., Inc., 657 F. Supp. 935, 2 U.S.P.Q. 2d (BNA) 1597, 1987 U.S. Dist. LEXIS 2801 (N.D. Ill. 1987).

Opinion

ORDER

BUA, District Judge.

This order concerns defendant’s motion for partial summary judgment pursuant to Fed.R.Civ.P. 56(c). Defendant maintains that Claims 1, 2, and 4 of plaintiffs’ U.S. Patent No. 4,022,479 are invalid under 35 U.S.C. § 103 (obviousness) and 35 U.S.C. § 112 (failure to particularly point out and distinctly claim that which constitutes the invention). For the reasons stated herein, defendant’s motion is granted.

I. FACTS

Plaintiffs Inpro, Inc. (Inpro) and David Orlowski, President of Inpro (Orlowski), instituted this action against defendant A.W. Chesterton Company, Inc. (Chesterton), alleging infringement on certain claims asserted in two patents owned by plaintiffs known as U.S. Patent No. 4,002,479 (’479 patent) and U.S. Patent No. 4,446,620 (’620 patent). Chesterton responds by denying infringement and counterclaiming for a declaration that the two patents are invalid. The ’620 patent is owned exclusively by Orlowski, while the ’479 patent is the property of Inpro. Since the filing of this action, plaintiffs voluntarily resubmitted the ’620 patent to the U.S. Patent and Trademark Office (PTO) for re-examination and withdrew their claims of infringement regarding this patent. Thus, the dispute presently pending before this court concerns only those claims Chesterton is alleged to have infringed: Claims 1, 2, and 4 of the ’479 patent.

The subject matter of the ’479 patent concerns an allegedly novel design of a labyrinth seal. Labyrinth seals are used in bearing housings to prevent the egress of lubricating fluid and the ingress of contaminants. Often, labyrinth seals are used in conjunction with rotary pumps. A rotary pump is a type of pump in which the pumping action is created by a rotating drive shaft connected to motor. A stationary housing holds the bearings on which the drive shaft rotates together with a lubricant for the bearings. To prevent the lubricant from escaping from the housing and contaminants from entering the housing, a seal is employed. Depending on the nature and use of the pump, a number of types of seals may be used to contain and protect the bearing housing’s lubricant from the external environment. Lip seals of felt are commonly employed to perform this sealing function. Felt lip seals typically involve the use of a fiberous ring made of wool and cotton that is affixed to the bearing housing so as to come into contact with the drive shaft as it rotates. The fiberous lip of the ring surrounds the circumference of the rotating shaft and affects a barrier to external contaminants as well as a containment for the housing lubricant. Because the life and effectiveness of such a friction based seal is somewhat limited, use of a lip seal is not always desirable.

Labyrinth seals are a second type of seal which is employed in a bearing housing to prevent the egress of lubricant and the ingress of contaminants. Labyrinth seals are noncontact seals and thus do not pose the friction or wear problems associated with lip seals. According to the prior art submitted by the parties, patented labyrinth seals have existed since at least 1939. See e.g., Young, U.S. Patent No. 2,281,905 (filed April 14, 1939).

The term “labyrinth” derives from the Greek word labyrintros and means a maze or obstructed passageway. Although laby *937 rinth seals can consist of many individual components, the type at issue in this case consists of only two basic parts: (1) a ring which is mounted on the stationary bearing housing; and (2) a cap which is fixed to and rotates with the revolving drive shaft. The stationary ring typically has one or more deep recesses in which a corresponding flange or set of flanges protruding from the rotating cap reside. When properly installed, the two parts fit together but never come into contact. Accordingly, friction is greatly reduced or eliminated. Yet, because the ring and cap do not contact, a potential exists for leakage through the narrow path between the parts. This leakage is minimized by the labyrinth arrangement of the path from which the seal gets its name. Fluids or particles traveling in such a path are less likely to enter the bearing housing if they encounter changes in direction or periodic pressure drops (caused by the path widening with its resulting change in flow velocity). The potential leakage path in any labyrinth seal includes at least one significant direction change and usually one pressure drop area.

The labyrinth seal disclosed by the ’479 patent is reproduced in Appendix A. The first piece of the ’479 patent is the ring member 40 which is fixed to the bearing housing 20 by means of an O-ring 45. The ring 40 does not touch the drive shaft 27. The second part of the ’479 seal is the cap 41 which is attached to the drive shaft 27 by means of an O-ring 51. The cap rotates with the revolving drive shaft. The feature claimed in the ’479 patent relating to preventing the seepage of contaminants from outside the bearing housing is the annular flange 52 on the cap which extends into the annular recess 48 on the ring cooperating with an exit hole 56 on the underside of the ring. As previously noted, the surfaces of the ring and cap do not touch. Fluids or particles from the housing’s exterior can enter the gap between the ring and cap. Due to the design of the flange 52 and recess 48, however, any such seepage must make several direction changes before reaching the interior of the housing. The result is that the labyrinth minimizes the flow of outside contaminants through this path when the drive shaft is at rest. While the drive shaft revolves, the centrifugal action of the flange and cap prevents contaminants from entering through the narrow gap between the seal parts. Any fluids or particles which do find their way into the narrow gap are then expelled through the exit hole 56 which leads to the exterior of the bearing housing.

The second function the ’479 seal serves is preventing the leakage of lubricants from the bearing housing along the drive shaft. The ’479 seal minimizes this leakage by a series of three grooves 46 around the inside of the stationary ring 40. These grooves 46 are connected at the bottom by a drainback groove 47, which is connected to the interior of the bearing housing 20. When the drive shaft rotates, lubricant which creeps along the surface of the shaft enters the grooves 46 and experiences a velocity and pressure drop. As a result, the creeping lubricant migrates from the shaft into the grooves and is returned to the housing reservoir by means of the drainback groove 47. Thus, leakage of lubricant from the bearing housing is prevented.

II. DISCUSSION

A. Summary Judgment and Burdens of Proof

Summary judgment for a movant is appropriate under Rule 56 of the Federal Rules of Civil Procedure “only if the pleadings, depositions and affidavits fail to disclose a genuine issue of material fact.” Gracyalny v.

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Bluebook (online)
657 F. Supp. 935, 2 U.S.P.Q. 2d (BNA) 1597, 1987 U.S. Dist. LEXIS 2801, Counsel Stack Legal Research, https://law.counselstack.com/opinion/inpro-inc-v-aw-chesterton-co-inc-ilnd-1987.