Full opinion text
MEMORANDUM OPINION DECKER, District Judge. This is a suit for infringement of United States Patent No. 3,139,213 (“ ’213”), entitled “Nestable Cup,” and for infringement of United States Patent No. 3,061,139 (“’139”), entitled “Self-Venting Package.” The ’213 patent was granted on June 30, 1964, upon an application originally filed on October 29, 1958, and divided on December 13, 1962, into the subject matter on which the ’213 patent was granted and the subject matter on which United States Patent No. 3,091,360 was granted on May 28, 1963. The ’139 patent was granted on October 30, 1962, upon an application filed on March 14, 1960. The applicant for both patents was Bryant Edwards, who has assigned all right, title and interest in both to plaintiff. Plaintiff, Illinois Tool Works, Inc. (“ITW”), is a Delaware corporation, with its principal place of business and offices in Chicago, Illinois. Defendant, Continental Can Company, Inc. (“Continental Can”), is a New York corporation, with its principal place of business in New York and with a regular and established place of business in Chicago, Illinois. In response to the complaint charging infringement, defendant filed an answer and counterclaim, asserting that the ’213 and ’139 patents are invalid and void and not infringed, and seeking a declaratory judgment under 28 U.S.C. §§ 2201, 2202 to this effect. This court has jurisdiction of this case under 35 U.S.C. §§ 271 and 281 and under 28 U.S.C. §§ 1338(a) and 2201. Venue in this district is proper. The case was tried before the court on October 31 and November 1, 1966, and on November 7-18, 1966. This memorandum opinion, containing findings of fact and conclusions of law in accordance with Rule 52(a), Federal Rules of Civil Procedure, is based upon the evidence produced at the trial-and upon the voluminous briefs filed by both parties. I have concluded that both the ’213 patent and the ’139 patent are valid and that Continental Can is guilty of infringement of both patents. For convenience, this opinion will first set forth the general factual background concerning this suit and then will separately discuss the ’213 and ’139 patents and issues raised with respect to each of them. * * * In general, the subject matter of both patents involves thin-wall plastic cups and containers, used for containing beverages or food, and with the form of such cups and containers, together with thin plastic lids. These products are formed from sheets of plastic by the use of molds and a process known as thermoforming. ITW initially became interested in the container market in late 1956, and began to produce plastic drinking cups on a commercial basis in 1958. In 1959, ITW began to manufacture plastic cottage cheese containers and supplied plastic lids for these containers, through a subcontractor, commencing in 1960. Continental Can has been in the cup and container market for a number of years, and prior to 1956 manufactured and sold paper drinking cups and food containers. Continental Can manufactured and sold thin-wall plastic drinking cups for use in vending machines on a sporadic basis from about 1956 through 1961. This product has been discontinued by Continental Can. In 1962 or 1963, Continental Can began to produce and sell plastic cottage cheese containers and lids and continues to do so at the present time. It is this latter product and activity by Continental Can which has directly given rise to this suit. The ’213 Patent 1. Subject Matter. In general, the subject matter of U. S. Patent No. 3,139,213 is a thin-wall plastic container, particularly of the expendable or throw-away variety. Such containers are typically used in vending machines, to hold hot and cold beverages, and in the field of dairy product containers, most particularly for cottage cheese products. The ’213 patent, entitled “Nestable Cup,” relates to the use of a Z-shaped stacking ring configuration around the side wall of the container. The purpose of this stacking ring is to permit the containers to nest one inside the other in tubular, telescopic fashion for economic storage and shipment and for use in vending machines and other machinery, where containers are dropped singly from the bottom of such a tube of containers to be filled with the appropriate beverage or product. The stacking ring is intended to permit such stacking to the extent of maximum telescoping without allowing the containers to wedge together, thereby providing for ready separation. The stacking ring is also intended to take advantage of the inherent resiliency of the plastic material and to embody a quality of resiliency in the column of containers, for the purpose of preventing the splitting of cartons of such containers during shipment if accidently dropped, and otherwise to prevent problems arising from the rigidity of such columns of telescoped containers. 2. Background and Issues in Suit. ITW first became interested in the packaging or container field in 1956, and became acquainted at that time with Mr. Charles Politis of Athens, Greece, who was promoting a thermo-forming machine and process. ITW negotiated an option with Politis in 1956 for his machine and process, and conducted several market surveys to determine the potential commercial value of thin-wall plastic containers. Following these surveys and several inspections of the Politis operation in Greece, ITW in the first part of 1957 signed a contract with Politis for a machine. Subsequent to this time, ITW assigned to one of its engineers, Bryant Edwards, the task of designing a suitable cup. Edwards designed a cup having a continuous Z-stacker configuration located at its rim and beneath the overhang of the rim curl, and in June 1957, Edwards took this design to Athens where sample cups were produced on the Politis machine. Edwards returned in July 1957, and a Politis machine was shipped to ITW at about the same time. Further sample cups were produced on this machine, but these were found to be unsatisfactory. Edwards then completely redesigned the cup, coming up with a cup utilizing a continuous Z-stacker configuration around the side wall below the rim of the cup. About this same time, Edwards also designed a cup utilizing the continuous Z-stacker configuration at the bottom of the cup. ITW submitted copies of this latter cup to Automatic Canteen, a major consumer of vending machine products, and in December 1957 Automatic Canteen gave ITW a verbal order for 1,000,000 of these cups, with minor modification. Molds were constructed and production begun early in 1958. In April 1958, ITW produced and shipped to Automatic Canteen 50,000 of these cups. However, the Politis machine was not efficient, and individual sorting and inspection of each cup was required. It was decided at this time to redesign the cup to provide for much greater production tolerances. The change consisted of adding an accentuated interrupted Z-stacker configuration to the existing Z-stacker ring at the bottom of the cup, and also further adding at spaced intervals camming nibs having lower surfaces oblique to the lower edge of the ring. The balance of the Automatic Canteen order was filled from about May 1958 through the fall of that year, and it was filled first with the accentuated interrupted Z-stacker cup and later with that cup having in addition the camming nibs. ITW has continued to produce and sell the latter cup, in part because of the cost of changing its molds and tools. ITW subsequently embodied the Z-stacker ring in an all-plastic tub for cottage cheese products in the dairy food industry. New molds were designed, and the tub contained a continuous Z-stacker configuration located on the side wall below the rim. In the summer of 1959, these tubs were produced and market tested by the Borden Company, and commercial production commenced shortly after that time. This production has continued to the present time, on the part of ITW as well as by its domestic and foreign licensees. On November 29, 1957, Bryant Edwards filed application Serial No. 699,-678, for a thin-wall plastic “nestable cup” containing a continuous Z-stacker ring located around the side wall of the cup below the rim. Subsequently, on October 29,1958, Edwards filed application Serial No. 769,057, also for a thin-wall plastic “nestable cup” with a continuous Zstaeker ring located on the side wall. Furthermore, this second application also described and claimed the interrupted accentuated Z-stacker ring and the camming nibs which were developed by Edwards in 1958 as a result of the commercial difficulties in producing cups to fill the Automatic Canteen order. Serial No. 769,057 was filed as a continuation-in-part of Serial No. 699,678 and Serial No. 699,678 was subsequently abandoned. After prolonged negotiation with respect to Serial No. 769,057, the Patent Office required a division under 35 U.S.C. § 121, and Serial No. 244,320 was filed on December 13, 1962. This application described and claimed a continuous Z-stacker ring, together with the additional feature of an oblique lower edge to this ring, located on the side wall of the cup. The application was successfully prosecuted, and the ’213 patent was issued on June 30, 1964. The feature of the camming nibs, some of which possessed oblique lower edges, in conjunction with a Z-shaped stacking ring was embodied in U. S. Patent No. 3,091,360, issued to Bryant Edwards on May 28, 1963, and also entitled “Nestable Cup.” ITW alleges infringement of four of the eleven claims in the ’213 patent. These are Claims 1, 5, 6 and 9. Claim 1 reads as follows: “A one-piece nestable seamless container of thin-wall plastic material of substantially uniform thickness, comprising a bottom and a side-wall of predetermined thickness integral therewith, the configuration of said bottom in central axial cross-section being such as to enhancé its resistance to deformation, said sidewall being joined to said bottom at a circumferential bottom margin and tapering generally upwardly and outwardly therefrom in diverging relation to an upper margin defining an open upper end, said sidewall being of substantial height to permit gripping thereof by a user, said upper margin having a rim of predetermined axial extent which is of sufficient increased lateral width relative to the thickness of the thin plastic sidewalls to lend required lateral strength at said open upper end, said sidewalls having circumferential stacking ring means formed therein, positioned below and spaced axially from said upper rim and having an axial extent greater than the axial extent of the rim portion and substantially less than the height of said sidewall, said stacking ring means including a circumferentially disposed intermediate support section having at its lower extremity circumferentially disposed externally projecting shoulder means and having at its upper extremity circumferentially disposed internal shoulder means projecting inwardly from the container sidewall and of smaller minimum diameter than the maximum diameter of said external shoulder. means and spaced upwardly from said bottom, said smaller diameter being less than said greater diameter by more than twice said sidewall thickness, said internal shoulder means adapted to form a shelf to co-act with the complementary external shoulder means of a like container to positively limit the extent of telescopic association of said containers and the maximum diameter of the container in the vicinity of said external shoulder means being sufficiently less than the diameter of the internal container wall surface adjacent and above said internal shoulder means to counteract jamming of like containers when stacked, both said internal shoulder means and said external shoulder means being substantially circumferentially continuous, said intermediate section of the stacking means inclined inwardly and upwardly toward the cup axis to present the aforesaid inner shoulder means and to provide a thin-wall, resilient support therefore when axial pressure is applied there-against by the external shoulder means of a like, telescopically associated container.” Claim 5 reads: “A container as set forth in claim 1 wherein at least one of said shoulder means has a surface associated therewith that is oblique relative to the container axis, the other shoulder means of an adjacent container being engageable therewith.” Claim 6 is identical with Claim 1, except that it provides that at least one of the shoulder means includes: “ * * * a circumferential surface oblique to the container axis, adapted for camming engagement with the other shoulder means of a like container telescopically associated therewith to enhance axial resiliency to a stack of containers in telescoped relation in response to axial pressures normally experienced by a stack of such containers.” Claim 9 reads: “A container as set forth in claim 6 wherein the oblique surface in axial section presents a substantially straight line.” The alleged infringing product manufactured by Continental Can is a cottage cheese container, of thin-wall plastic material and with a single continuous Z-shaped stacking ring located on the side wall below the rim. Thus, the other claims of the ’213 patent, which cover a Z-stacker ring located at the bottom of a cup and the use of a series of circumferential rings, together with a Z-stacker ring, on the side of the cup for gripping and possible heat-transfer purposes, are not involved in this suit. Essentially, the defenses interposed by Continental Can are two-fold: (1) an assertion that the ’213 patent is invalid and therefore cannot be infringed, and (2) an assertion that in any event, Continental Can’s product does not infringe the patent. In support of the invalidity defense, Continental Can asserts a number of specific grounds. The first ground is that of anticipation under 35 U.S.C. §§ 102(a) and 102 (b). With respect to the § 102(a) defense, Continental Can asserts, in particular, that experiments and developments of its own engineers involving thin-wall plastic containers prior to August 1957, the alleged conception date for the Edwards invention, constituted complete anticipations of this invention. Continental Can further asserts that various prior art patents and publications also constituted complete anticipations of the Edwards invention. Under § 102(b), Continental Can initially seeks to establish that, based upon the file wrapper history of the ’213 patent, ITW is not entitled to the November 29, 1957, date or to the October 29, 1958, date as the date of application. According to this argument, the date of application is December 13, 1962. On this basis, Continental Can asserts that ITW’s own commercial production and sale of cups to Automatic Canteen in 1957 and 1958 and sale of cottage cheese containers to Borden Company commencing in 1959 constituted public use and placing on sale of the invention in this country more than one year prior to the date of the patent application, under § 102(b). Furthermore, Continental Can asserts that its own developments from 1956 to 1960 and other prior art patents and publications were public uses and sales more than one year prior to Edwards’ application under § 102(b). A second ground is that the ’213 invention was obvious to a person having ordinary skill in the art at the time of the invention, under the provisions of 35 U.S.C. § 103. The prior art relied upon by Continental Can for this ground consists of its own developments and advertising from 1956 to 1960, together with a number of prior art patents. This same prior art is also relied upon with respect to the anticipation defense, under §§ 102(a) and 102(b), as previously noted. A third ground consists of the assertion that the claims of the ’213 patent fail to point out and to claim the subject matter of the invention, with the particularity and distinctness required by 35 U.S.C. § 112. A fourth ground, based generally upon the developmental history of Edwards’ various cup and container designs, together with the file wrapper of the ’213 patent, lies in the assertion that the alleged novelty of the invention is so limited as to deprive it of “invention,” and therefore that it was not patentable. These various grounds raised by Continental Can with respect to the general defense of invalidity are further asserted affirmatively by Continental Can in support of its counterclaim for a declaratory judgment that the ’213 patent in invalid. Continental Can’s non-infringement defense proceeds upon the theory that even if the ’213 patent is valid, its product does not infringe. In particular, it is asserted by Continental Can that its product does not infringe Claims 5, 6 and 9 of the ’213 patent in that the product does not have an oblique shoulder, as delineated in these claims. Furthermore, it is argued that the product does not have resiliency in the sense in which that word is employed in Claim 1 of the ’213 patent, but rather that any resiliency in the product is simply inherent in the plastic material of which it is composed. Continental Can also raises the defense of file wrapper estoppel in connection with its argument of non-infringement. This defense is based upon Edwards’ cancellation of certain claims following their rejection by the Patent Office, which claims were contained in the December 13, 1962, divisional application and Edwards’ substitution of the present claims referring to “resiliency.” Before discussing in detail each of these defenses and the various grounds urged in support of them, it is necessary to define exactly the nature of the invention described and claimed in the ’213 patent. This invention consists of a single circumferentially continuous Z-shaped stacking ring configuration, with an upper and a lower shoulder and a middle section inclined inwardly and upwardly relative to the cup axis, which stacking ring is located below the rim, on the side wall of the thin-wall plastic cup. It is clear from the drawings, from the specification describing the drawings, and particularly from Claim 1 that this stacking ring is singular, is continuous around the cup, and is located as described above. Whether these features are significant with respect to patentability over prior art having double or interrupted rings, or locating the ring at a different place on the container, are issues which I will discuss at the appropriate place in this opinion, in connection with the respective prior art. 3. The ’213 Filing Date. Continental Can asserts that the ’213 patent is wholly invalid because it was fully anticipated by prior art patents and publications, by ITW’s own sales in 1958 and 1959 of cups and containers and by Continental Can’s developmental activities and programs during the period of 1956 to 1960. Initially, the issue of the effective date of application for the ’213 patent must be resolved. This date is especially relevant with respect to which products and activities occurring between 1956 and 1960 should be considered, both as to the one-year time bar of § 102(b) and as to the date of invention for purposes of § 102(a). The date is in fact a crucial one for ITW, since it is clear that if the earliest date ITW is entitled to is the date of the divisional application — December 13, 1962— as contended by Continental Can, ITW’s own solicitation of the order from Automatic Canteen in December 1957 would constitute a placing on sale, and the actual commercial production and shipment of the cups to Automatic Canteen in 1958, as well as the production and sale of cottage cheese tubs commencing in 1959, would constitute a public use of the invention “in this country, more than one year prior to the date of the application for patent in the United States,” and thus invalidate the patent under § 102(b). ITW contends that the ’213 patent is entitled to the November 29, 1957, filing date for Claim 1, and to the October 29, 1958, filing date for Claim 6 (and presumably for Claims 5 and 9 as well). This contention is based upon the provisions of 35 U.S.C. §§ 120, 121, to the effect that a patent is entitled to the benefit of an earlier filed patent application if three basic requirements are met: (1) co-pendency of applications, (2) cross-reference to the earlier application, and (3) continuity of disclosure. Both the co-pendency and cross-reference requirements were satisfied; however, Continental Can contends that there was no continuity of disclosure, insofar as the original application filed on November 29, 1957, made no reference to “resiliency” or to any similar characteristic. Furthermore, Continental Can argues that while the October 29, 1958, application referred to resiliency, it did so with respect to the camming nibs and not with respect to the Z-stacker ring. It is argued that not until the divisional application was filed on December 13, 1962, was resiliency related to the Z-stacker ring. Thus, Continental Can contends that there was no disclosure of resiliency to the extent required by 35 U.S.C. § 112, either in the November 29, 1957, application or in the October 29, 1958, application. Continental Can relies upon the testimony of its expert witness Yahdenburgh, who concluded from an examination of the various file wrappers that new matter was contained in the divisional application of December 13, 1962, in that resiliency was for the first timé related to the Z-stacker ring. On this basis, Vandenburgh stated that this was not a proper division and that ITW was only entitled to this date as the date of filing the application for the ’213 patent. Continental Can also relies upon the case of Graham v. John Deere Co., 383 U.S. 1, 86 S.Ct. 684, 15 L.Ed.2d 545 (1966), in which the Supreme Court characterized as an “afterthought” the patentee’s argument for the first time on appeal that one of the major advances of his invention with respect to a plough was its “free-flexing” quality throughout the shaft of the plough. However, the Court also found that this feature was not in fact significant in the patent and that the switching of the shank and hinge plate which permitted the “free-flexing” was obvious to anyone having ordinary skill in the prior art at the time of invention. Thus, the rejection of the argument of free-flexing in John Deere did not depend upon the “after-thought” characterization. Moreover, that case did not involve a continuation-in-part and division. I do not find the “afterthought” argument to be applicable to the present case, where the resiliency feature was presented to and argued before the Patent Office and where this feature was inherent in the design and drawings of the cup, which were identical in each application. See also Lincoln Engineering Co. of Illinois v. Stewart-Warner Corp., 303 U.S. 545, 549-550, 58 S.Ct. 662, 82 L.Ed. 1008 (1938). The case of Indiana General Corp. v. Lockheed Aircraft Corp., 249 F.Supp. 809 (S.D.Calif.1966), which Continental Can also cites, can be distinguished. That case involved the filing of a continuation-in-part application following the original application, and the court did not allow the patentee the benefit of the earlier date on the grounds that the original application failed to disclose fully the “square” characteristic of the loop of the product. On this basis, the court held that the patentee’s sales of the product at about the date of the original application constituted a commercial use more than one year prior to second application and therefore invalidated the patent under § 102(b). The court stressed that the “square” characteristic of the loop of the product was the essence of the invention and held that even though the particular product having a square loop property was generally disclosed in the original application, this disclosure did not satisfy § 112 in that it did not disclose how the square loop characteristic was produced or how it was to be used or applied. Under the circumstances of this case, I am convinced that the disclosure as to resiliency in the first two applications was sufficient to entitle ITW to the benefit of those dates, with respect to the various claims of the ’213 patent. Specifically, Figs. 1-4 of the ’213 patent which relate to Claim 1 and which depict a single continuous Z-shaped stacking ring located on the side wall below the rim of the cup are identical to Figs. 1-4 in the November 29,1957, application and to Figs. 1-4 in the October 29, 1958, application. The same material, thickness, shape and location are involved in all three applications. More importantly, the drawings and descriptions in each application portray the same interrelationship and interaction between the cups with respect to the Z-stacker rings when the cups are telescoped together in a column. As Continental Can’s expert Vandenburgh admitted, the property of resiliency claimed in the ’213 patent was inherent and fully present in the earlier applications. The inherency argument finds support in the familiar patent law principle that a patentee is entitled to all of the benefits and advantages of his patent, including uses and functions of which he was not aware at the time the patent was granted. See, e. g., Radio Corp. of America v. Radio Engineering Laboratories, 293 U.S. 1, 12-14, 54 S.Ct. 752, 78 L.Ed. 1453, reh. denied 293 U.S. 522, 55 S.Ct. 66, 79 L.Ed. 634 (1934); King-Seeley Thermos Co. v. Tastee Freez Industries, Inc., 357 F.2d 875, 880 (7th Cir.), cert. denied 385 U.S. 817, 87 S.Ct. 38, 17 L.Ed.2d 56 (1966); Talon, Inc. v. Union Slide Fastener, Inc., 266 F.2d 731, 734 (9th Cir. 1959). While the court in the Indiana General case declined to apply this principle, it did so on the basis that the new use must result from the product or not involve a new principle or not be an unobvious use. In the present case, the resiliency feature or property does directly result from the structure, which is clearly described and depicted in both the November 29, 1957, application and in the October 29, 1958, application. No new principle or wholly unobvious use, as was involved in the Indiana General case, exists in this case. Furthermore, although these two applications both contained references to rigidity, it is clear that this rigidity was lateral rigidity, created by the use of numerous concentric rings or ridges about the cup, so as to prevent the cup from collapsing when grasped in a hand, and was not axial rigidity, so as to make a later claim of axial resiliency a possible contradiction and new principle, as Continental Can contends. For these reasons, I hold that the requisite disclosure of resiliency existed in the November 29, 1957, application, and therefore that ITW is entitled to the benefit of that date as to the effective filing date for Claim 1 of its ’213 patent, under § 120 and § 121. ITW is also entitled to the October 29, 1958, filing date for Claims 5, 6 and 9 of the ’213 patent, insofar as the application filed on that date first fully described and disclosed the use of oblique shoulders with respect to the Z-stacker ring. However, even if ITW is not entitled to the November 29, 1957, date, it is entitled to the October 29, 1958, date for Claim 1, since the application of the latter date clearly stated: “In all of the embodiments of the invention heretofore shown and described, the outlines of the cup are generally the same. In each instance, sections are provided for utilizing the inherent resiliency of the plastic, either directs, or by a wedging action or by both, whereby to impart a resilient characteristic to a stack of such cups telescoped together.” When this statement is considered together with the drawings and descriptions which fully depicted the Z-stacker ring, it is clear that full disclosure for purposes of § 112 was present. Since none of ITW’s acts in placing cups on sale or in actually producing and selling cups occurred prior to December 1957, the one-year time bar of § 102(b) does not invalidate the ’213 patent, whether the November 29, 1957, date or the October 29, 1958, date is given effect. 4. Anticipation. As the Supreme Court stated in the recent case of Graham v. John Deere Co., supra, 383 U.S. at 12, 86 S.Ct. at 691, the patentability of a particular device depends “upon three explicit conditions: novelty and utility as articulated and defined in § 101 and § 102, and non-obviousness * * * as set out in § 103.” Continental Can does not raise lack of utility as a defense to the ’213 patent in this suit, but does contend that the patent lacked both novelty and nonobviousness, and therefore is invalid. These tests are separate and involve different standards and considerations. In general, statutory novelty, as contained in § 102, requires a determination that the particular invention has not been made before, and therefore that it is in fact new. See generally Graham v. John Deere Co., supra, at 14, 86 S.Ct. 684 (quoting from H.R. Rep. No. 1923, 82d Cong., 2d Sess. at 7 (1952); S.Rep. No. 1979, 82d Cong., 2d Sess. at 6 (1952), U.S.Code Congressional and Administrative News, p. 2394). The statutory requirement of novelty is set forth in § 102(a), which provides: “A person shall be entitled to a patent unless — -(a) the invention was known or used by others in this country, or patented or described in a printed publication in this or a foreign country, before the invention thereof by the applicant for patent.” Where the invention was previously known or used by others in this country, it is said to have been anticipated. Similarly, courts have employed the term anticipation in connection with § 102(b), which provides: “A person shall be entitled to a patent unless — (b) the invention was patented or described in a printed publication in this or a foreign country or in public use or on sale in this country, more than one year prior to the date of application for patent in the United States”. Since § 102(b) embodies a one-year time bar and is most frequently raised where the patentee or applicant himself has used or sold his invention more than one year prior to his application for patent, it is probably more appropriate to consider this section as defining a situation under which an applicant loses his right to a patent and not as defining novelty. See, e. g., Application of Foster, 343 F.2d 980, 987-988 (C.C.P.A.1965). However, both §§ 102(a) and 102(b) involve prior knowledge, use or sale of the invention which is the subject matter of the patent, and therefore employ a similar standard as to the nature of the prior knowledge, use or sale with respect to its identity or similarity to the patented invention. See generally 1 Deller’s Walker on Patents §§ 77-82 (2d ed. 1964). Under both §§ 102(a) and 102 (b), the test of anticipation is framed in terms of the identity of the prior device with the later patented invention or inventionon which a patent is sought. The test is frequently stated as “disclosure in the prior art of a thing substantially identical with the claimed invention.” 1 Deller’s Walker on Patents § 57 at 237 (2d ed. 1964). “Substantially identical” in turn has been defined as occurring where the two inventions “perform substantially the same function or office in substantially the same way, and produce substantially the same result.” Delta Mfg. Co. v. E. L. Essley Mach. Co., 153 F.2d 905, 906-907 (7th Cir. 1946) (quoting from 48 Corpus Juris § 27 (1929)), cert. denied 328 U.S. 867, 66 S.Ct. 1376, 90 L.Ed. 1637 (1946). Furthermore, it has been generally stated that there is substantial identity of inventions where the subsequent invention does not involve inventive skill over the first but would have been obvious to a person having ordinary skill in the art. See, e. g., Duo-Flex Corp. v. Building Service Co., 322 F.2d 94, 96 (5th Cir. 1963); Ranco, Inc. v. Gwynn, 128 F.2d 437, 443 (6th Cir. 1942). These definitions would appear to be overly broad and to confuse anticipation with the separate test of invention, presently embodied in the statutory language of “non-obviousness” in § 103. It should be recognized that anticipation is a narrow technical defense, which does not raise for consideration all that the prior art discloses, but occurs only where the same or virtually identical device or invention has previously been disclosed. See, e. g., Monroe Auto Equipment Co. v. Heckethorn Mfg. & Sup. Co., 332 F.2d 406, 414-415 (6th Cir. 1964). As stated by the Court of Appeals for the Tenth Circuit: “Anticipation is strictly a technical defense and unless all of the same elements are found in exactly the same situation and united in the same way to perform an identical function, there is no anticipation.” McCullough Tool Co. v. Well Surveys, Inc., 343 F.2d 381, 398 (10th Cir. 1965), cert. denied 383 U.S. 933, 86 S.Ct. 1061, 15 L.Ed.2d 851 (1966). See also Stauffer v. Slenderella Systems of California, 254 F.2d 127,128 (9th Cir. 1957). In this case, where the same prior art knowledge, uses, patents and publications are cited both as anticipations under § 102 and as evidence of the obviousness of the ’213 invention under § 103, it is important to distinguish between these separate defenses and to adhere to a narrow standard of virtual identity in every aspect of the inventions to find that an anticipation has occurred. Furthermore, such identity must exist in a single prior structure, patent or description, and it is not proper in this case to combine the various prior art references cited by Continental Can with respect to what each discloses. See, e. g., Monroe Auto Equipment Co. v. Heckethorn Mfg. & Sup. Co., supra, 332 F.2d at 414; Borkland v. Pedersen, 244 F.2d 501, 502 (7th Cir. 1957); but see Application of Foster, supra, 343 F.2d at 988-989. Since the ’213 invention is embodied in a patent, the presumption of validity under 35 U.S.C. § 282 attaches, and the burden of proof rests upon Continental Can to show prior knowledge or use under § 102(a) or prior public use or sale under § 102(b) of the invention by “clear and cogent evidence.” See, e. g., Corona Cord Tire Co. v. Dovan Chemical Corp., 276 U.S. 358, 382-383, 48 S.Ct. 380, 72 L.Ed. 610 (1928); Devex Corp. v. General Motors Corp., 321 F.2d 234, 238 (7th Cir.1963). Similarly, the burden is upon Continental Can in asserting anticipation on the basis of prior art patents and publications to sustain this claim by clear and convincing evidence. A patent or publication “is to be measured as anticipatory, not by what might be made out of it, but by what it clearly and definitely discloses.” McCullough Tool Co. v. Well Surveys, Inc., supra, 343 F.2d at 398. Furthermore, “a prior patent or other publication to be an anticipation must bear within its four corners adequate directions for the practice of the patent invalidated.” Dewey & Almy Chemical Co. v. Mimex Co., 124 F.2d 986, 989 (2d Cir.1942). In particular, Continental Can asserts that various developments, experiments and uses of plastic containers by its own engineers and employees in 1956 and 1957, prior to the alleged Edwards’ conception date in August 1957, and “involving extensive development and use of stacking rings with Z configuration,” completely invalidate the claims of the '213 patent. These activities, according to Continental Can, amounted to knowledge or use of the ’213 invention by its engineers and employees in this country before Edwards’ date of invention, within the meaning of § 102(a). ITW counters this argument with the assertion that these developments were incomplete or abandoned experiments, and thus were not anticipations under § 102(a). ITW further asserts that in any event none of these developments embodied the exact Edwards’ invention and therefore were not anticipations or prior art. Section 102(a) deals with knowledge or use of the invention by others prior to the date of invention by the applicant for patent. “Invention” is normally defined as consisting of conception plus reduction to practice of the particular device. See, e. g., Wright Aeronautical Corp. v. General Motors Corp., 166 F.2d 636, 640 (7th Cir. 1948); Stub v. United States, 63 F.Supp. 748, 749-750, 105 Ct. Cl. 397 (1946) cert. denied 329 U.S. 751, 67 S.Ct. 81, 91 L.Ed. 647 (1946). In this case, the evidence clearly reveals that Edwards completely revamped his cup design in August 1957, and produced the cup design which was subsequently embodied in the first ’213 application, filed on November 29,1957, and which is presently depicted as Figs. 1-4 in the patent. The evidence further reveals that sample cups of this design were actually produced on the Politis machine of ITW in September 1957. Thus, the date of invention for the ’213 patent was no later than September 1957, which is consistent with the previous discussion of the effective date of filing to which ITW is entitled. It is only Continental Can’s developmental activity prior to September 1957 which is relevant for purposes of prior knowledge or use under § 102 (a). Continental Can’s developmental activity in the area of plastic cups prior to September 1957 consisted of its 7% V cup program, extending from 1956 to 1957, and its 7AB cup program, extending from 1956 into 1958. These programs were primarily carried on through the efforts of Mr. William Miller, an engineer employed by Continental Can throughout this period and presently so employed. The purpose of the programs, as admitted by Miller, was to develop a plastic “cup, machinery, process, everything concerned with it, as soon as we could at the least amount of money,” and to place this cup into commercial use. Transcript p. 1305. Numerous designs, samples and some production cups were produced in the course of these programs, and Continental Can engaged in advertising various cups and cup designs from 1957 to 1959. Continental Can also conducted developmental activity in 1956 and 1957 with respect to plastic food containers, including a % gallon ice cream container. These various cups, cup designs and food containers employed a number of different stacking configurations. The first thin-wall plastic thermo-formed cups designed and produced by Continental Can in the first part of 1956 as a part of the 7% V cup program under Miller’s direction were smooth-walled cups, modeled generally on the design of existing paper cups, with a rim-stacking configuration which was circumferentially continuous and in the shape of a “lazy S.” In effect, this configuration was simply a groove in the inside of the side wall of the cup, located just below the rim. A cup in this general form and design was subsequently produced in commercial quantities and apparently sold for use in hot-drink vending machines in late 1956 and early 1957. However, such cups do not contain a circumferentially continuous single Z-shaped stacking ring located beneath the rim on the side wall of the cup, which is the subject matter of the ’213 invention. Edwards, in his development of the ’213 invention, began with a rim-stacking configuration, but abandoned this altogether for the sidewall configuration developed in August and September 1957. Miller’s testimony at the trial revealed that the 7% V cups with rim-stackers were not successful and frequently jammed and telescoped. Other cup designs in the 7^ V cup program employed single side-wall continuous vertical, as opposed to Z-shaped, stacking configurations and stacking facilities inset into the bottom and spaced from the side wall of the cup. The evidence presented at the trial revealed that considerable jamming difficulties existed' in the 734 V cups, due to side-wall nesting and the tendency of the cups to override the shoulders of the various stacking configurations. In other words, the stacking configurations were deficient and unacceptable for commercial use, a fact borne out by the subsequent variety of stacking designs which Miller investigated and tested in the various 7AB cups and cup designs. In the 7AB cup developmental activity, Miller turned to the use of a double Z-stacker ring configuration. In the first model in this project, the “A” cup, the double ring was located at the rim, with the upper ring being continuous and the lower ring, immediately adjacent to the upper, being divided into three protruding segments. Some of these cups were produced and tested by Miller and other employees of Continental Can in early 1957, but no commercial production occurred. A second model was the “B” cup, designed and produced in limited quantities in late 1956 and early 1957. The cup contained a stacking ring at the rim, below which was located a configuration composed of twelve semi-circular protrusions, generally inclined inwardly and upwardly relative to the axis of the cup. A third cup model was the “C” cup, designed and produced in limited quantities for internal testing in February 1957. These cups contained a stacking ring at the rim with a partial second ring consisting of four spaced segments located immediately below the upper ring. Both rings contained oblique lower shoulders. In June or July 1957, sample cups for testing were produced in limited quantity by Continental Can. These cups contained indented, semicircular intrusions about the base of the cup, in the side wall, which indentations were inclined upwardly and inwardly and were also slightly wider at the top than at the bottom. The cups also contained a single segmented (in four parts) protruding ring in the side wall of the cup below the rim, similar to the lower ring in the “C” cup model. In late spring of 1957, Miller designed and produced in limited quantity certain cups composed of paper with plastic bottoms. The bottoms contained indentations in the side walls for stacking purposes, similar to those in the all-plastic cups described above. These combination paper and plasic cups were never commercially produced and the project was abandoned in late 1957 as being too expensive. During this period, two of the various cup designs developed in the course of the 7AB cup project were embodied in commercial projects. These cups were produced and presumably sold in the late spring or early summer of 1957. The first such cup, designated as the “D production cup,” involved a rim-stacking configuration consisting of an upper ring and lower partial ring, both of which had oblique lower shoulders, and virtually identical to the configuration on the “C” model cup. In May 1957 Continental Can advertised this cup in a national trade magazine. The second cup, the “7AB Special” cup, was a smooth-walled cup having a stacking configuration at the bottom of the side wall, which configuration consisted of twelve semicircular indented and inclined intrusions, as described previously. Apparently, Continental Can continued to experience difficulties with respect to jamming, telescoping, and axial rigidity of a column of cups in these and in the other various 7AB cup designs and models. Continental Can also introduced evidence relating to developmental activity during the first seven or eight months of 1957 with respect to food containers composed of thin-wall thermo-formed plastic. These containers included a double Z-shaped stacking ring configuration similar to that just described in connection with the “D” production cup, except that the upper ring on the food container was not immediately adjacent to the rim and was not under the overhang of the rim curl. Rather, the upper ring was located on the side wall of the container below the rim. The second, segmented ring was located immediately below the upper ring. There was no evidence that any of these containers were actually produced in quantity or sold commercially at this time. In 1957 Continental Can also designed and tested some models of a rectangular Yz gallon ice cream container composed of polyethylene and of polystyrene plastic. Some of these models employed a double rim stacking configuration with vertical mid-sections. Others contained double rim-stacking configurations which were generally Z-shaped, but vertical at the four corners of the container. This project never progressed beyond an initial design and testing phase. With the possible exception of some of the food containers which had a single continuous Z-shape stacking ring located below the rim in the side wall, together with a lower segmented ring, none of the above-described designs or models was sufficiently identical to the '213 invention to have constituted an anticipation of that invention. Each of these designs contained significant and material differences from the ’213 invention. In particular, the rim-stacking configuration which many of these designs employed was the same sort of configuration which Edwards designed in May 1957 and which he expressly abandoned in August 1957. The bottom stacking configurations, and various other segmented configurations, involving either intrusions or protrusions, were quite different from the ’213 single continuous Z-shaped ring configuration. Miller himself admitted at the trial that none of his various plastic cup or food container designs, developed from 1956 through 1960, involved “a single side-wall continuous Z-shaped stacking ring.” Transcript pp. 462, 464. Moreover, Miller on June 29, 1961, in connection with the proposed production of a 16 ounce cottage cheese container, stated in a letter: “Stacking will be controlled by the bottom section. I have reverted to the stacking design we used on the 7 ounce cups we made several years ago, correcting the one mistake we made. The bottom of the stacking band is now a solid ring.” Continental Can argues that once the basic geometry of a Z-stacking ring configuration is conceived and adopted, the use of a segmented, double ring, or other variation is merely a matter of choice and preference — only a difference of degree. Continental Can also argues that the exact geometry of the Z-stacking ring is dictated by the requirements of the plastic material and by the need to provide that the cup can be readily stripped from the mold. However, Miller’s extensive design activity and his constant change of designs, without once actually producing the ’213 invention, serves to counter these arguments. Miller was searching for a better design, and" he finally employed a single side-wall continuous Z-shaped stacking ring in the cottage cheese containers, developed in 1962 and 1963. It was not merely a matter of preference or choice for him. Moreover, even if Continental Can’s arguments are valid, the “differences of degree” involved between the various Miller designs and the ’213 invention were sufficient to negative the status of any of the former as anticipations, within the narrow and technical definition of that term. With the exception of the few cups which were actually produced and sold commercially, there is also a second basis for rejection of each of the various Miller cup designs and models as an anticipation of the ’213 invention. These were merely experimental designs and models, used for internal tests and inspection by Continental Can. They did not constitute prior knowledge or use of the invention which was accessible to the public. See, e. g., Gayler v. Wilder, 51 U.S. (10 How.) 477, 13 L.Ed. 504 (1850). Although a single prior use may be sufficient to constitute an anticipation, Coffin v. Ogden, 85 U.S. (18 Wall.) 120, 124, 21 L.Ed. 821 (1873), and although this use need not be a commercial one, Corona Cord Tire Co. v. Dovan Chemical Corp., supra, 276 U.S. at 382-385, 48 S.Ct. 380, it must be an actual and complete use of the particular invention. In the technical sense of the phrase, there probably was the requisite “reduction to practice” of the various Miller cup designs for which molds were actually made and samples produced. However, these models were used solely for tests and experiments inside the laboratories of Continental Can, in the course of the development of commercial products. In no sense were the models considered as final products, but merely as steps along the path of designing a final product. Under these circumstances, it is clear that, with the exception of the few commercially produced cups, all of these various designs and models were merely experiments, subsequently and quickly abandoned for other designs and models. See, e, g., Connecticut Valley Enterprises, Inc. v. United States, 348 F.2d 949, 951-952 (Ct.Cl.1965). As such, they are without any status as either prior art, with respect to § 103, or anticipations, with respect to §§ 102(a) and 102(b). See e. g., Gayler v. Wilder, supra. At most, all of the evidence of Miller’s extensive developments and various designs merely indicates that he was engaged at the time in a course of conduct aimed at designing and producing a practical commercial plastic vending cup and other plastic containers. He was experimenting with this end in mind, and it is clear that this was not achieved until 1962 or 1963, after ITW’s extensive production and sale of cottage cheese containers embodying the ’213 invention. See, e. g., The Telephone Cases, 126 U.S. 1, 547-567, 8 S.Ct. 778, 31 L.Ed. 863 (1888). On the basis of the foregoing analysis and discussion, I conclude that none of Continental Can’s developmental activity with respect to plastic cups and containers and occurring during 1956 or 1957 constituted an anticipation of the ’213 invention. More specifically, none of these designs was knowledge or use prior to the date of invention of the ’213 patent, within the meaning of § 102(a), and similarly none of them was a public use or sale more than one year prior to the filing date of the application for the ’213 patent, within the meaning of § 102 (b). In fact, none of these designs appeared or was in any sense reduced to practice more than one year prior to the November 29, 1957, filing date, which pertains to Claim 1 and to the basic invention of the ’213 patent, as I have previously found. Furthermore, none of the other prior art patents or publications, which will be discussed in detail in connection with Continental Can’s defense of obviousness under § 103, was sufficiently identical to the ’213 invention to have constituted an anticipation of that invention, under either § 102(a) or § 102 (b), as generally asserted by Continental Can. See, e. g., McCullough Tool Co. v. Well Surveys, Inc., supra, 343 F.2d at 398; Dewey & Almy Chemical Co. v. Mimex Co., supra, 124 F.2d at 989. 5. Non-obviousness. Section 103 provides, in part: “A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102 of this title, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains.” This section, added to the patent law in 1952, codified the existing judicially-created requirement of invention for patentability. See Graham v. John Deere Co., supra, 383 U.S. at 17, 86 S.Ct. 684. As stated by the Supreme Court in the John Deere case, this section involves a factual inquiry, under which “the scope and content of the prior art are to be determined; differences between the prior art and the claims at issue are to be ascertained ; and the level of ordinary skill in the pertinent art resolved. Against this background, the obviousness or non-obviousness of the subject matter is determined.” Graham v. John Deere Co., supra, at 17, 86 S.Ct. at 694. The relevant time with respect to which this analysis is to be conducted is the time of invention, and courts must be wary to avoid applying hindsight in light of subsequent knowledge or disclosures. See, e. g., Zegers v. Zegers, Inc., 365 F.2d 156, 159 (7th Cir. 1966). Furthermore the “apparent simplicity of an invention when viewed in retrospect” is not a test of invention or indicative of obviousness. Amp Inc. v. Vaco Products Co., 280 F.2d 518, 521 (7th Cir.), cert. denied 364 U.S. 921, 81 S.Ct. 286, 5 L.Ed.2d 260 (1960). ■ An inventor is charged with knowledge of all that the prior art, taken as a whole, discloses with respect to the subject matter of the invention, and a person skilled in the art is further presumed to have had at his disposal all relevant prior art constructions and patents, as well as disclosures contained in patent applications pending before the Patent Office at the time of the filing of the patent in suit. See, e. g., Hazeltine Research, Inc. v. Brenner, 382 U.S. 252, 86 S.Ct. 335, 15 L.Ed.2d 304 (1965); Walker v. General Motors Corp., 362 F.2d 56, 60 (9th Cir. 1966). The patent is presumed to be valid. 35 U.S.C. § 282. A party asserting that a patent is invalid “has a heavy burden of establishing invalidity by clear and convincing evidence.” Walt Disney Productions v. Fred A. Niles Communications Center, Inc. 369 F.2d 230, 234 (7th Cir. 1966). This presumption is strengthened where the validity of the patent is challenged on the basis of prior art cited by the Patent Office. Shumaker v. Gem Mfg. Co., 311 F.2d 273, 275 (7th Cir. 1962). However, “there is no presumption of validity as against prior art not before the patent office.” Skirow v. Roberts Colonial House, Inc., 361 F.2d 388, 390 (7th Cir. 1966). Where the Patent Office cites some prior art, but not other equally relevant and similar prior art, the presumption is weakened only to the extent that the teaching of the uncited art is not disclosed in the cited art. See T. P. Laboratories v. Huge, 371 F.2d 231, 234-235 (7th Cir. 1966); Jaybee Mfg. Corp. v. Ajax Hardware Mfg. Corp., 287 F.2d 228, 229 (9th Cir. 1961). In support of its general contention that the ’213 patent is invalid because its subject matter was obvious to a person having ordinary skill in the art in 1957, Continental Can relies primarily upon eight patents, some of which were cited by the Patent Office in considering the ’213 patent and some of which were co-pending with the ’213 patent. Continental Can further contends that each of these “primary patents” contains a complete teaching of the ’213 patent, and especially of Claims 1, 5, 6 and 9, which are involved in this suit, and thus offers these patents as anticipations under § 102, as well as evidence of obviousness under § 103. The first patent relied upon by Continental Can is Geuder, U. S. Patent No. 795,437 (July 25, 1905). This patent discloses washtubs of heavy-gauge sheet metal, which contain a series of corrugated rings located on the side wall below the rim and circumferentially continuous about the side wall. These rings were designed to permit the nesting of the tubs, one inside another, without contact between the side walls of the tubs, for economic storage and shipment. In particular, the purpose of the rings (denominated “inturned and outturned beads” by the patentee) was to prevent wedging of the tubs or damage to them in separation, when stacked one inside the other, which wedging or damage was specifically caused by the protruding seam on the side of the tub, resulting from the joinder of the sheet metal. An “incidental advantage” of this construction, according to the patentee, was the protection of the drop handles of the tubs, which are located on the outside of the tub, just below the rim. Although the Geuder patent was cited by the Patent Examiner who considered the October 29, 1958, application, there is no evidence that Geuder was specifically cited against the subject matter which eventually matured into the ’213 patent and Geuder is not cited in the file of the ’213 patent. Rather, Geuder was cited with respect to the subject matter of U. S. Patent No. 3,091,360, which was granted following the division of the October 29, 1958, application and which involved the use of camming nibs and protrusions in connection with a Z-shaped stacking ring on thin-wall thermo-formed plastic containers. Geuder is officially cited in the file on the ’360 patent, and the patentee, before the Patent Office, specifically distinguished it (Application Serial No. 769,057, at pp. 89-90) on the basis that it did not involve downwardly extending protuberances (or nibs) which were essential in guiding light-weight plastic cups and in facilitating the entrance of air between such cups when stacked to allow gravitational separation in vending machines. Thus, it does not seem that Geuder was cited with respect to the ’213 patent, and the presumption of validity of the latter patent does not exist as against the disclosures of Geuder. Nevertheless, Geuder contains significant differences from the subject matter of the ’213 invention to the extent that it does not anticipate that invention and does not demonstrate that the subject matter of the ’213 patent would have been obvious to a person having ordinary skill in the art in 1957. While Geuder does disclose the use of a stacking configuration wherein the lower shoulder of the inside tub rests upon the upper shoulder of the outside tub and side-wall nesting is prevented, this configuration is not Z-shaped. The Z-shaped characteristic is essential to the ’213 patent, as Edwards testified, providing resiliency as well as non-jamming nesting of cups. Geuder is not concerned with these matters and in fact involves a non-analogous art and use. The purposes of the Geuder invention, as indicated, were substantially different from those of the ’213 invention. A different material and means of creation of the product were involved. Geuder was not concerned with lightweight plastic cups and containers which are stacked in vending machines and other mechanical equipment and which are subjected to severe stress relative to their composition. Although Geuder generally involves a container and a stacking configuration, and for those reasons can be said to be pertinent prior art in the sense that a person skilled in the art would reasonably have been expected to look to Geuder for a solution, see, e. g., Graham v. John Deere Co., supra, 383 U.S. at 35, 86 S.Ct. 684, it does not supply this solution and does not render the solution obvious. Evidence to this effect is strongly shown in this case by Miller’s various unsuccessful experiments and designs with plastic cups involving numerous stacking configurations, some of which were quite similar to Geuder. Miller was a person who was obviously and admittedly skilled in the art. Miller testified that he had, prior to 1957, seen tubs of the Geuder design and had actually designed equipment for producing such tubs. Miller further testified that in his opinion the ’213 invention was suggested by Geuder. Yet, Miller, with all of his experience and skill, did not produce the ’213 invention during the course of his extensive experimentation until 1962 or 1963, after ITW’s cottage cheese container had been produced and sold in quantity and had met with extensive commercial success. At about that time, in 1962, Miller referred to his earlier experiments involving stacking rings as containing a “mistake” and changed his design to one virtually identical to the ’213 patent, as embodied in ITW’s cottage cheese containers. A second “primary” patent relied upon by Continental Can is Pfalzgraf, U. S. Patent No. 1,324,432 (December 9,1919). This patent also relates to heavy-gauge sheet metal washtubs, and discloses the use of a continuous Z-shaped ring about the circumference of the tub and located on the side wall below the rim. This ring contains an oblique upper and lower shoulder, and serves to prevent side-to-side rocking or tilting of the tubs when stacked one inside another. It does not function as a stacking device, since this feature is accomplished by the handles of the respective tubs. When the tubs are stacked in normal fashion, there is, in fact, no co-action between the respective rings, a