Townsend Engineering Co. v. Hitec Co. (829 F.2d 1086, 1987)

FRIEDMAN, Circuit Judge.

This is an appeal from a judgment of the United States District Court for the Northern District of Illinois granting summary-judgment for the defendant in a patent infringement suit. The court found that there was no infringement, either literal or under the doctrine of equivalents. We affirm.

I

The invention the patent (No. 3,694,853) (the ’853 patent) discloses is a sausage-stuffing machine. This case involves the “looper horn” claimed in the ’853 patent, which loops stuffed sausages on hooks for further processing.

The appellant Townsend Engineering Company (Townsend) obtained the '853 patent by assignment from its inventor, Charles Austin Greider. Townsend also owned an earlier and now expired U.S. Patent (No. 3,191,222) (the ’222 patent), on a sausage-stuffing machine, issued to its chief executive officer, Ray T. Townsend.

Encasing machines made according to the ’222 patent had difficulty handling delicate casing material because of the shape of the machines’ looper horn. In his specification in the ’853 patent, Greider explained that he could avoid the tearing problems encountered in machines manufactured under the ’222 patent by changing the shape and geometry of the looper horn:

The horn extension shown in U.S. Pat. No. 3,191,222 is helical or spiral in shape whereas the horn extension of the present invention is substantially straight and disposed at an angle with respect to the rotational axis of the bearing means (horn base 202) which supports the horn extension.

The application for the ’853 patent originally included 27 claims. Claim 27 of the application, which as amended is now claim 5 of the ’853 patent, the claim covering the looper horn, is the only claim relevant in this appeal. In pertinent part, claim 27 set forth

an elongated tube-like horn extension having first and second ends and a longitudinal base [sic: bore] extending there-through for slidably receiving said casing, said first end of said horn extension being adapted to receive said casing; bearing means on said support having an axis of rotation and rotatably supporting said first end of said horn extension, the longitudinal axis of said horn extension being substantially straight and forming an angle with respect to said axis of rotation of said bearing means____

In the first Office Action, the patent examiner rejected claim 27 as anticipated by the looper horn of the ’222 patent. See 35 U.S.C. § 102 (1982). In response, Greider cancelled claim 27 and substituted claim 30, which ultimately became claim 5 of the ’853 patent. The most significant differences between claim 30 and claim 27 relate to the shape and length of the looper horn. The relevant portion of claim 30 is reproduced below, with underlining and brackets showing the language added to and deleted from claim 27:

an elongated tube-like horn extension having first and second end portions [ends] and a [longitudinal] bore extending therethrough and therebetween for slidably receiving said casing [, said first end of said horn extension being adapted to receive said casing], said second end portion having a length substantially greater than the length of said first end portion,

bearing means on said support having an axis of rotation and rotatably supporting said first end portion of said horn extension, said second end portion having a [the] longitudinal axis [of said horn extension] which is [being] substantially straight and which is angularly disposed [and forming an angle] with respect to the longitudinal axis of said first end portion and angularly disposed with respect to said axes of rotation of said bearing means____

In the remarks explaining the substitution of claim 30 for claim 27, Greider noted that the looper horn of the application differed from that in the ’222 patent because the latter was both curved and rotating:

In the specification, [Greider] recognized that looping horns such as the one disclosed in the [’222 patent] have been previously used for looping link casings but it was specifically stated at page 18 of the specification that previous horns have not been adapted to handle delicate casings satisfactorily. The horn extension shown in the [’222] patent is helical or spiral in shape whereas the horn extension of the present invention is substantially straight and disposed at an angle with respect to the rotational axis of the bearing means which supports the horn extension. The result of the device described in claim 30 is that the casings are gently swung back and forth for looping over the hooks of the conveyor. This action is gentler and less likely to cause tearing of the casing than the action obtained from the previous helical horn.

With these changes, claim 30 was issued as claim 5 of the ’853 patent.

Townsend filed the present suit against appellee HiTec Co., Ltd. (HiTec), alleging that HiTec’s “Auto Wienker” sausage-stuffing machine infringed claim 5 of the ’853 patent. The patented and accused looper horns are illustrated below:

HiTec inoved for summary judgment of non-infringement, asserting that the Auto Wienker di