Full opinion text
DECISION AND ORDER RANDA, District Judge. This patent infringement case comes before the Court for decision after a three-week court trial. The Court has carefully considered all of the trial testimony and exhibits, the entire pretrial record, the parties’ post-trial findings of fact and conclusions of law and the parties’ post-trial briefing. Based on this review, the Court finds the patent claims-in-suit invalid. The Court further finds that, with the exception of two machines, one sold and one not sold, the claims-in-suit are not infringed, either literally or under the doctrine of equivalents, by the accused machines. FINDINGS OF FACT I.PARTIES AND CLAIMS 1. The plaintiff, Nordberg Inc. (“Nord-berg”), is a Delaware corporation with its principal place of business located in Milwaukee, Wisconsin. Nordberg manufactures and sells machinery used in mining and mineral aggregate production. This machinery includes rock crushers, which form the subject matter of the patent in suit. (Nordberg Findings of Fact (“NFOF”) at ¶¶ 1, 3; Tel-smith Findings of Fact (“TFOF”) at ¶ 1; Trial Transcript (“TT”), Vol. 1 at 13-14.) 2. The defendant, Telsmith, Inc. (“Tel-smith”), is a Delaware corporation with its principal place of business located in Me-quon, Wisconsin. Telsmith also manufactures and sells machinery used in mining and mineral aggregate production, including rock crushers. (NFOF at ¶¶ 2, 5; TFOF at ¶ 2; TT, Vol. 2 at 289-90.) 3. Nordberg and Telsmith are among four major manufacturers competing in the market for conical crushers. Nordberg has been in the market since the 1920’s and is the number one supplier of cone crushers in the world with over 16,000 installations worldwide. (NFOF at ¶¶ 5-6; TT, Vol. 4 at 622, 632-637, 676, Vol. 8 at 1539.) 4. Nordberg is the owner, by assignment, of United States Patent No. 4,478,373, entitled “Conical Crusher”, issued on October 23, 1984 (“the 373 Patent”). (NFOF at ¶ 4; TFOF at ¶ 3.) Nordberg also owns Reexamination Certificate B1 4,478,373, which issued on January 30, 1990 and involved a reexamination of the original 373 Patent. (NFOF at ¶ 4; TFOF at ¶3.) 5. Nordberg contends that certain conical crushers manufactured or developed by Tel-smith infringe (or contributorily infringe) upon claims 8-11 and 13 of the 373 Patent. These crushers include Telsmith’s HOOF, the “10” series, and models 52, 57 and 84. (TFOF at ¶ 4.) II. HISTORY AND GENERAL OPERATION OF CONICAL CRUSHERS 6. Conical crushers have existed since the early 1900’s. (TFOF at ¶ 5.) They are primarily used in the mining industry to extract minerals from rock and in the aggregate industry to crush rock into various sizes for construction purposes. (TT, Vol. 1 at 14.) This suit involves crushers used for the latter purpose. 7. Conical crushers generally comprise a cylindrical and stationary lower frame assembly which encloses a gyrating conical head (138). (NFOF at ¶ 7; TFOF at ¶ 5; TT, Vol. 1 at 15-16.) Above the lower frame assembly is an upper frame assembly which can move vertically relative to the lower frame. (NFOF at ¶ 7; TFOF at ¶ 5; TT, Vol. 1 at 15-19.) The upper frame includes a concave bowl (126) surrounding the conical head and a hopper (116) with a central opening to allow the entry of rock. (NFOF at ¶ 7; TFOF at ¶ 5; TT, Vol. 1 at 16.) The rock drops through the hopper into the space between the bowl and the conical head, which is called the crushing cavity. (Id.) Crushing results from the gyratory motion of the head. (NFOF at ¶ 7; TFOF at ¶ 5; TT, Vol. 1 at 16-17.) That is, the access of the head is mounted at a slight angle to the access of the machine. (NFOF at ¶ 7; TT, Vol. 1 at 16.) Because of this slanted access, the crushing cavity, as the head rotates, is narrow at one point on the circumference of the bowl and wider at another point. (NFOF at ¶ 7; TT, Vol. 1 at 16-17.) These two points can be referred to as the “closed” and “open” points of the crushing gap, respectively. (Id.) As the head rotates, the closed and open points similarly rotate around the crushing cavity. (Id.) Rock dropping into the crushing cavity is squeezed between the rotating head and the bowl at various points along the circumference of the bowl. (Id.) The squeezing action crushes the rock into a smaller size generally consistent with the size of the gap in the crushing cavity at the point at which the rock is struck. (TT, Vol. 1 at 16-17, 22-23.) This all happens very quickly. In a typical crusher, the head will complete 4-6 full rotations a second. (NFOF at ¶ 7; TT, Vol. 1 at 17.) The falling rock is typically struck 3^1 times before passing through the crushing cavity. (TT, Vol. 1 at 17.) 8. In order to crush rock, the movable upper frame containing the concave bowl must be held or “biased” against the lower frame. (NFOF at ¶ 8; TFOF at ¶ 5.) Tremendous forces are required to hold the frames together against the resistance forces exerted by the rock. (NFOF at ¶ 8; TT, Vol. 1 at 21.) The hold down force ranges from approximately 300,000 pounds of spring force for a small crusher to 1.2 million pounds for a large crusher. (Id.) 9. Although the upper frame is held against the lower frame during normal crushing, conical crushers typically have provisions allowing the upper frame to raise relative to the lower frame during three basic functions: adjustment, tramp relief and clearing. (NFOF at ¶ 9; TT, Vol. 1 at 22-24.) 10. Adjustment relates to setting the vertical distance between the head and the bowl at the relatively closed gap on the gyrational cycle of the head. (NFOF at ¶ 9; TT, Vol. 1 at 22-23.) That distance determines the size of the crushed rock product. (Id.) In order to control and/or vary the size of the product, conical crushers must have some way of adjusting the distance between the head and the bowl. (Id.) Even if a consistently-sized product is desired, the head must continually be lowered to accommodate for normal wear of the crushing elements. (Id.) 11. Tramp relief relates to the passing of uncrushable material. During the mining or quarrying of rock, large pieces of uncrushable material, such as steel or metal tools, often become inadvertently mixed in with the rock to be crushed. (NFOF at ¶ 10; TFOF at ¶ 6; TT, Vol. 1 at 24-25.) This material is called tramp. (Id.) If a piece of tramp enters a rock crusher and is larger than the setting of the relatively closed gap between the head and bowl, it will become caught in the crushing cavity. (Id.) The crusher will continually try to crush the tramp, which it cannot do. (Id.) If the upper frame was rigidly held against the lower frame at this point, extreme overstresses would develop and damage the crusher. (Id.) Thus, all conical crushers provide means for the upper frame to yield and raise under the pressures exerted by uncrushable tramp. (Id.) That “means”, whatever form it may take, is generally referred to as “tramp relief’ or “tramp release”. 12. Clearing relates to removing jammed material from a stalled or shut down crusher. Occasionally, a crusher will stall or experience a power failure during crushing. (NFOF at ¶ 11; TT, Vol. 1 at 27-28.) In such cases, the crusher shuts down with a full load of rock in the crushing cavity. (Id.) Some of this rock becomes jammed or “pinched” in the cavity. (Id.) The crusher will not restart in that condition because the electric motor which powers the crusher is not strong enough to overcome the forces exerted by the jammed rock in the crushing cavity. (Id.) The rock must first be cleared from the crushing cavity. (Id.) Depending on the type of crusher involved, clearing is either done manually, with picks and crowbars, or mechanically, through some means of raising the upper frame so that the jammed rock may fall through. (Id.) 13. Another important feature in many conical crushers is an “abutting relationship” between the upper and lower frames during normal operation, created by the abutment of complementary beveled U-shaped surfaces on each frame. (NFOF at 1120; TFOF at ¶ 12.) The abutment provides a positive, mechanical reference point for the crusher setting and for the return of the upper frame to a fixed operating position upon the passage of tramp material or the clearing of the crusher. (Id.) The abutting relationship has been well known in the crusher art for decades. (Id.) 14. Until the early-to-mid 70’s, the most prevalent and traditional means for biasing the upper frame against the lower frame and for tramp release was the use of coiled springs. (NFOF at ¶ 12; TFOF at ¶ 7.) In spring crushers, the springs are mounted and precompressed between the frames so that the upper frame is biased toward the lower frame during normal crushing. (Id.) When tramp material enters the crushing cavity, it raises the upper frame relative to the lower frame, further compressing the springs. (Id.) The upward travel of the upper frame temporarily creates a larger crushing cavity, allowing the tramp material to pass without damaging the crusher. (Id.) Once the tramp passes, the springs expand and thereby lower the upper frame into its original position. (Id.) 15. The major disadvantage with spring crushers is that springs cannot be used to clear a stalled crusher. (NFOF at ¶ 14; TFOF at ¶ 7.) A stalled spring crusher must be cleared manually with picks and crowbars, which is a process that can take hours to complete. (Id.; TT, Vol. 1 at 27-28.) Such downtime means lost production for the crusher user. Another disadvantage is the hazardous nature of large, compressed steel springs. Due to the possibility of entire springs or parts of broken springs being released at high speeds and causing injury, such springs create safety problems for assembly, operating and maintenance personnel. (NFOF at ¶ 13; TFOF at ¶ 7.) A third disadvantage is that springs add a significant amount of weight to the crusher, which is an important factor for customers desiring a portable crusher that can be moved between job sites. (Id.) 16. Another biasing means known in the crusher art since the 50’s is the use of single-acting hydraulic or pneumatic cylinders. (NFOF at ¶ 15; TFOF at If 8.) Like springs, single-acting cylinders are generally mounted between the upper and lower frames. (Id.) Single-acting hydraulic cylinders have one of two chambers of the cylinder pressurized with oil and single-acting pneumatic cylinders have one of two chambers pressurized with air. (Id.) The pressurized end biases the upper frame toward the lower frame during normal crushing. (Id.) During tramp release, the pressures created by the tramp raise the upper frame, displacing the oil in hydraulic cylinders into a corresponding accumulator and/or compressing the air in pneumatic cylinders. (Id.; see also, NFOF at ¶ 17.) After the tramp passes, the decrease in pressure causes the displaced oil to return to the pressurized end of the hydraulic cylinders and/or allows the air to decompress in the pressurized end of the pneumatic cylinders, thereby lowering the upper frame to its original position. (Id.) Like spring crushers, the major disadvantage of single-acting cylinders is that they do not provide a means for automatic clearing. (NFOF at ¶ 15; TFOF at ¶ 8.) 17.A third biasing means known in the crusher art since the late-60’s or mid-70’s is the use of double-acting hydraulic or pneumatic cylinders. (NFOF at ¶ 16; TFOF at ¶9.) Like springs and single-acting cylinders, double-acting cylinders are generally mounted between the upper and lower frames. (Id.) Unlike single-acting cylinders, however, double-acting cylinders pressurize both chambers of the hydraulic cylinders with oil and both chambers of the pneumatic cylinders with air, the chamber above the piston being the “rod end” and the chamber below the piston being the “blind end”. (Id.) During normal crushing, the rod end is pressurized in order to bias the upper frame against the' lower frame. (Id.) During tramp release, the upper frame is raised by the tramp, displacing the oil from the rod end of the hydraulic cylinders and/or compressing the air in the rod end of the pneumatic cylinders, similar to tramp relief using single-acting cylinders. (NFOF at ¶ 16; TFOF at ¶ 10.) To clear the crusher, however, oil is mechanically directed into the blind end of the hydraulic cylinders at the same time that oil is displaced from the rod end of such cylinders, and/or air is mechanically directed into the blind end of pneumatic cylinders at the same time that air is further compressed in the rod end of such cylinders. (NFOF at ¶ 16; TFOF at ¶ 11.) The oil or air in the blind end raises and suspends the upper frame to allow the rock in the crushing cavity to fall through. (Id.) After the cavity is cleared, the oil or air in the blind ends of these cylinders is allowed to exit, thereby allowing oil to return to, or the air to decompress in, the rod end of the cylinders, causing the upper frame to lower and return to its crushing position. (Id.) 18. Prior to the mid-70’s, conical crushers with double-acting hydraulic cylinders often “floated” the upper frame relative to the lower by adjusting the amount of hydraulic fluid both above and below the pistons, thus lacking the normal “abutting relationship” between the upper and lower frames and preventing the operator from accurately maintaining a uniform setting of the crushing gap. (NFOF at ¶¶ 18-19.) 19. As suggested by their simultaneous usage and development in the crusher art, hydraulic and pneumatic cylinder systems— though different in their respective components and manner of operation — were considered to be interchangeable biasing and release means before the invention of the 373 Patent. (TFOF at ¶ 113; TT, Vol. 12 at 2244-2245; Ex. 8, Col. 7, Line 55 — Col. 8, Line 23 [Gruender].) This is not to say that one does not have advantages over the other. The most significant disadvantage with pneumatic cylinders is that they use a compressible fluid, normally air, which operates much like a spring and thus poses similar safety concerns because of the significant pressures involved. (NFOF at ¶ 17.) Pneumatic cylinders also offer less control over component movement because compressed air is not as precise a force as oil. (Id.) Pneumatic cylinders are also larger than hydraulic cylinders and may take longer to complete tramp release than hydraulic cylinders. (Id.) Nevertheless, the two types of cylinders were interchangeable and indeed the very differences discussed above — particularly the safety factor — suggested to one of ordinary skill in the art the substitution of hydraulic cylinders for pneumatic. (TFOF at ¶ 114; TT, Vol. 1 at 102-104, Vol. 6 at 1130, Vol. 12 at 2245.) III. SPECIFIC PRIOR ART A. Cited To PTO During Initial Prosecution. 1. Telsmith 1100E. 20. The Telsmith 1100E crusher was a conventional spring-type conical crusher having coil springs for tramp relief and upper and lower frames abutting at complimentary beveled surfaces. The crusher did not have a mechanical means for clearing the machine. It has been sold by Telsmith since at least 1974. (NFOF at ¶¶ 179-181.) 2. El Jay/Cedarapids. 21. The El Jay/Cedarapids Rollercone has been on the market since the 1950’s and is still sold. The Rollercone has single-acting hydraulic cylinders with normally pressurized upper chambers to bias the upper frame into an abutting relationship with the lower frame during normal crushing. The abutment is created by complementary beveled surfaces. The upper chambers of the cylinders are closely coupled to, and in fluid communication with, an accumulator which receives fluid displaced from the upper chambers during tramp relief. Initially, it appears the Rollercone had no mechanism for clearing the machine, but El Jay recently added a separate hydraulic jack to perform clearing. (NFOF at ¶¶ 190-196; TFOF at ¶¶ 100-108.) B. Cited During Reexamination. 22. On June 6, 1989, Nordberg filed a Request for Reexamination of the 373 Patent in light of three patents that were not cited during the initial prosecution: UK Patent 801,091 to Wedag (“the 091 Patent”), U.S. Patent No. 3,604,640 to Webster (“Webster”), and U.S. Patent No. 4,615,491 to Batch et. al. (“Batch”). (NFOF at ¶81.) Nordberg admitted in its request that “[tjhese prior art patents ... raise a substantial new question of patentability with regard to at least claim 8 of Gieschen”. (Ex. 4 at 3154.) 1. The 091 Patent. 23. The 091 Patent was particularly relevant because it contained the features which Gieschen had argued were missing in the prior art during the initial prosecution, i.e., double acting hydraulic cylinders providing both tramp relief and clearing. (NFOF at ¶ 82; Ex. 4 at 3384-85.) Nordberg distinguished the 091 Patent, however, by its lack of an abutting relationship between the upper and lower frames. (NFOF at ¶ 82; Ex. 4 at 3384-86.) 2. Webster. 24. Similarly, Webster disclosed double-acting hydraulic cylinders. (NFOF at ¶ 82; Ex. 4 at 3386-87.) While these cylinders provided for mechanical clearing, it appears coil springs were used for tramp relief and there was no abutting relationship between the upper and lower frames. (Id.; see also, Ex. 4 at 3156-58.) 3. Batch. 25. Batch disclosed a conical crusher with double acting hydraulic cylinders used for tramp relief and clearing and which had the abutting relationship between the upper and lower frames. (NFOF at ¶ 83.) Gholz, Nordberg’s legal expert, admitted at trial that Batch poses a serious threat to the validity of the 373 Patent if it is considered prior art. (TT, Vol. 5 at 921.) Nordberg distinguished Batch, however, under a 35 U.S.C. § 131 Declaration by Gieschen establishing conception prior to the Batch patent filing date of October 15, 1979. (NFOF at ¶ 83; Ex. 4 at 3387-88; see also, COL at ¶ 48.) C.Never Cited To PTO. 1. Saunders. 26. The Saunders patent is a Nordberg patent that was issued in 1964 and which was not before the Examiner during the prosecution of the 373 Patent or the reexamination. (NFOF at ¶ 146; TFOF at ¶¶ 34-35.) 27. Saunders was a Nordberg employee. (TT, Yol. 1 at 96-7.) John Gieschen, the inventor of the 373 Patent, knew Saunders, whom he remembered as primarily a grinding mill designer, but did not become aware of Saunders’ work on crusher designs or of the existence of the Saunders patent until a few weeks before trial. (Id.; see also, NFOF at ¶ 146.) 28. Like the 373 Patent, Saunders discloses a conical crusher with a stationary lower frame assembly and a vertically movable upper frame assembly which is biased towards or held against the lower frame. (TT, Vol. 2 at 236-37, Vol. 3 at 436.) It discloses a crusher head assembly mounted on a support means for gyratory motion relative to the frame assemblies. (TT, Vol. 2 at 236-37, Vol. 3 at 437.) It discloses an adjustable bowl mounted to the upper frame for vertical movement relative to the frame and head assemblies. (Id.) It discloses an eccentric means for imparting gyratory motion to the crusher head and a drive means for driving the eccentric means. (Id.) It has hydraulic cylinders, one end of which are pressurized in a normally operating crusher mode to exert a hydraulic biasing force to hold said frame assemblies together in abutting relationship. It has a normally pressurized accumulator in fluid communication with one end of said cylinders. (TT, Vol. 2 at 23ÍM0, Vol. 3 at 444.) It is unclear, however, whether Saunders discloses a release means including biasing means and lifting means connected to said upper and lower frames for releasably biasing said upper frame into an abutting relationship with said lower frame, said release means comprising a plurality of double acting hydraulic cylinders. (TT, Vol. 2 at 237-38.) Saunders is also unclear as to whether fluid is displaced from the hydraulic cylinder to the accumulator during tramp relief. Saunders does not have a single signal that simultaneously deactivates said biasing means and activates said lifting means, or vice versa. (TT, Vol. 3 at 441-42.) And while the hydraulic pistons are connected to one of said frame assemblies, the hydraulic cylinders are hot connected to the other of said frame assemblies. 2. Jeffrey/Wedag crusher. 29. In 1962, Robert Stafford, Telsmith’s current president, was an engineer for Jeffrey Manufacturing Co. in Columbus, Ohio (“Jeffrey”). (TT, Vol. 6 at 1162; NFOF at ¶ 127.) Jeffrey had obtained a license to manufacture, for sale in the U.S., a cone crusher developed by a German company known under the acronym Wedag, located in Bochum, West Germany. (TT, Vol. 6 at 1166-66; NFOF at ¶ 127.) Wedag had sold several of the licensed cone crushers, but none in the U.S. (TT, Vol. 10 at 1813-14; NFOF at ¶ 128.) In 1962, Stafford was given the task of converting the licensed Wedag drawings, which were written in German with metric dimensions, to the English language and English dimensions. (TT, Vol. 6 at 1165-66; NFOF at ¶ 129.) The conversion process took approximately one year. (Id.) 30. The Wedag crusher was basically a conical crusher in which the upper frame was held in relation to the lower frame by eight double acting hydraulic cylinders. (TT, Vol. 6 at 1168, 1171-75; NFOF at ¶ 130.) The crusher did not provide a bevelled seat between the upper and lower frames. (TT, Vol. 7 at 1287-88; NFOF at ¶ 130.) Instead, eight horizontally oriented shock absorbers or snubbers maintained the position of the upper frame in the horizontal plane. (TT, Vol. 6 at 1168, 1171-75; NFOF at ¶130.) The double acting hydraulic cylinders maintained the position of the upper frame in the vertical plane. (Id.) 31.The Jeffrey/Wedag crusher did not have “an adjustable bowl mounted to said upper frame assembly for vertical movement relative to said frame assemblies and head assembly”. Moreover, it is unclear whether the release means in the Jeffrey crusher “releasably bias[ ] said upper frame into an abutting relationship with said lower frame”. It is also unclear whether the accumulator received fluid displaced from the cylinder during tramp relief. 3. Wedag brochure. 32. A 1961 brochure published by Wedag teaches the same type of conical crusher as the one developed by Jeffrey, i.e., one with double-acting hydraulic cylinders to perform both tramp relief and clearing. As explained above, however, it is unclear whether the upper frame has an “abutting relationship” with the lower frame during normal crushing. (FOF at ¶ 31.) It is also unclear whether the cylinders are in fluid communication with the accumulator during tramp relief. (Id.; see also, NFOF at ¶¶ 205-207; TFOF at ¶¶ 117-121.) 4. Bjarme. 33. The Bjarme ’571 patent was issued June 8, 1954 and discloses a conical crusher having double-acting pneumatic cylinders to perform both tramp relief and clearing. During normal crushing, the normally pressurized upper chambers of the cylinders bias the upper frame against the lower frame in an abutting relationship. (NFOF at ¶¶ 197-204; TFOF at ¶¶ 109-116.) IV. DEVELOPMENT OF MODEL B AND HOOF 34. With this general history and prior art in mind, we turn to Nordberg’s development of the invention at issue and the relatively simultaneous development by Telsmith of similar technology. Nordberg’s efforts were embodied in a project called the Model B. Telsmith’s efforts were embodied in a project called the 1100F. Both projects involved the development of a conical rock crusher using double-acting hydraulic cylinders to perform both tramp release and clearing and to bias the upper frame against the lower frame in an abutting relationship. A. Nordberg’s Model B. 35. In the early 1970’s, Nordberg management made a decision to develop a new crusher to replace or modernize Nordberg’s SYMONS conical crusher, which had been a very successful product but which was beginning to lose market share to newer crushers developed by Nordberg’s competitors. (NFOF at ¶ 32-33; Ex. 120; TT, Vol. 1 at 47-49.) John Giesehen, a Nordberg engineer, was appointed to head the “Model B” project, and in February of 1974 he outlined management’s basic design objectives. ■ (Id.) These included, among others, low manufacturing cost, low height and weight configuration for greater portability, ease of field maintenance, and mechanisms for adjustment, tramp relief and clearing. (Id.) At this stage there was no requirement that the latter mechanisms be hydraulic, spring-based or pneumatic — just that they be mechanical for greater ease and speed. (TT, Vol. 1 at 47-48.) There was also no express reference to the need for an abutting relationship between the upper and lower frames of the crusher. (Ex. 120.) Instead, management authorized an “inside out” approach, which allowed Giesehen and his design team to start from scratch and build whatever type of crusher they thought best, regardless of whether it incorporated features from Nord-berg’s existing crushers and for which tooling was already available. (NFOF at ¶ 33; Ex. 120; TT, Vol. 1 at 50-51.) 36. In keeping with the foregoing design objectives, particularly the specified weight and cost reductions, Giesehen and his team would often use lower cost but unproven ideas, relying on eventual prototype testing to reveal any deficiencies. (NFOF at ¶ 34; Ex. 123 at 405; TT, Vol. 1 at 54-55.) Indeed, in the design and development of any new crusher, extensive testing under commercial conditions is necessary to prove the crusher’s durability and commercial viability. (NFOF at ¶ 35; TT, Vol. 1 at 71, Vol. 4 at 599.) Development of the Model B progressed with the expectation of such testing in mind. (NFOF -at ¶ 35; TT, Vol. 1 at 54-55.) 37. The consideration of many potential mechanisms for tramp relief, clearing and adjustment began as early as February, 1974. (NFOF at ¶¶ 36-37; Ex. 120.) It was recognized early on that the clearing feature could be combined with the same mechanism as the adjustment or tramp relief features. (Exs. 121,122; TT, Vol. 1 at 56-7.) Giesehen considered every possible combination of features that would do the job, including hydraulic, pneumatic and spring-based systems. (NFOF at ¶ 37; TT, Vol. 1 at 60; Ex. 126.) A mechanism very similar to the double-acting hydraulic system eventually chosen was first drawn, along with various other options, in September of 1974. (NFOF at ¶ 37; Ex. 126; TT, Yol. 1 at 58-9.) • 38. The final tramp relief and clearing system was selected in February, 1977, based upon an analysis performed by T. Braun. (Ex. 124.) Under that analysis, the various systems conceptualized in 1974 were narrowed down to a group of twelve, again including hydraulic, pneumatic and spring-based systems. (NFOF at ¶ 38; Ex. 124; TT, Vol. 1 at 60-61.) The twelve were compared in terms of their relative cost and weight. (Ex. 124; TT, Vol. 1 at 61-2.) In a meeting on or around February 10, 1977, Nordberg selected Version 3, originally drawn in September, 1974, and which employed the hydraulic tramp release and clearing configuration found in the 373 Patent. (Ex. 124; NFOF at ¶ 38; TT, Vol. 1 at 61-2, 65.) 39. The conception of the entire Model B for design purposes occurred by April 25, 1977. (NFOF at 1Í39; TT, Vol. 1 at 66; Ex. 66.) On May 2, 1977, at a meeting of Nord-berg marketing and engineering personnel, Gieschen presented the design of the Model B and described its operation. Drawings of the crusher were disclosed and discussed. (NFOF at ¶ 40; TT, Vol. 1 at 52-53, 59; Exs. 66,123.) The presentation included a discussion of the construction and the operation of the hydraulic tramp release and clearing system. (NFOF at ¶ 41; Ex. 123; TT, Vol. 13 at 2399-2405.) At this time, Gieschen already had a general idea as to how the hydraulie circuit would be constructed and had drafts of such a circuit drawn up, but none of the drafts could be produced for trial. (TT, Vol. 1 at 65-66, 157.) Gieschen’s testimony is supported, however, by Uhle Sa-want, a participant at the May 2, 1977 meeting, and by the printed minutes of that meeting, both of which relate the extensive amount of detail provided regarding the types, dimensional characteristics and loading of the various components of the hydraulic tramp release and clearing system, indicating that the design of the hydraulic tramp release and clearing system was generally complete. (NFOF at ¶41; Ex. 123; TT, Vol. 13 at 2399-2405.) 40.Detailed manufacturing drawings were prepared for the Model B in the summer of 1978 and the initial assembly of the prototype crusher was completed in January, 1979. (NFOF at ¶42; Ex. 4, Bates 3189; Exs. 284, 288; TT, Vol. 1 at 62-70.) Upon assembly of the Model B prototype, a three-stage testing program was developed, beginning with no-load shop tests, progressing to short-term crushing at Nordberg’s Test Center, and finishing with field tests at an actual production site. (NFOF at ¶¶ 43^15; TT, Vol. 1 at 66-72, Vol. 2 at 252-56, Vol. 3 at 568-70, Vol. 13 at 2393-99; Exs. 62, 64, 73.) Numerous strain gauges were attached to the machine during each phase of testing to monitor the machine. (Id.) The no-load shop tests, beginning in January, 1979, focused on testing the machine’s lubrication system. (Id.) The clearing mechanism was satisfactorily tested during both the shop tests and the test center tests, at one point placing a steel block in the crushing cavity and creating conditions comparable to a plugged crusher. (Id.) Actual crushing was performed at the test center in April and May of 1979. (Id.) Because of limited space and equipment, the crushing runs were of short duration and used relatively soft limestone, but the runs were intended to show whether “crushing would actually be accomplished.” (Id.) The tramp mechanism was also tested at the test center by feeding tramp material into the crushing cavity under no-load conditions. (Id.) After completion of the test center tests on or around June 1, 1979, Gieschen concluded that the Model B was “workable for its intended purpose” and he reiterated that opinion during trial. (TT, Vol. 2 at 187-88; TFOF at ¶ 89.) 41. Shop tests and the tests at the test center did not, however, prove the long-term reliability and commercial viability of the new crusher. (NFOF at ¶ 46; TT, Vol. 1 at 71-72, Vol. 3 at 580-81, Vol. 7 at 1227-28, Vol. 13 at 2413-16, 2451; TFOF at ¶90.) This can only be determined by relatively long-term field tests under commercial conditions. (Id.) Even after a new crusher enters the market, Nordberg continues to monitor it for several years in order to determine its reliability. (TT, Vol. 13 at 2416.) 42. Nordberg arranged to conduct field tests at a commercial plant in Phoenix, Arizona owned by The Tanner Companies (“Tanner”). (NFOF at ¶ 48.) An agreement outlining the terms and conditions of the field test was executed in August, 1979. (Id.; Ex. 129.) Among other things, the agreement provided that the Model B remained the property of Nordberg and that Nordberg would have control over the operation of the Model B throughout the field test. (NFOF at ¶¶ 48-49; Ex. 129.) It also provided that Tanner and Nordberg employees would have “free and unlimited access to the test crusher at all times” and that visits by third parties “[were] to be discouraged” and only made when mutually agreeable to both Tanner and Nordberg. (NFOF at ¶ 50; Ex. 129.) The agreement did not impose any obligation of secrecy or confidentiality upon Tanner or its employees regarding the Model B or its use at the facility. (Ex. 129.) 43.Because of the nature of the operation, Tanner’s plant was in a relatively wide open location. (TT, Vol. 10 at 1749-55.) There were no special barriers erected around the Model B. (Id.) The quarry itself was enclosed by a fence that had a gate which was open during the daytime. (Id.) There was little to no control over who came in and out of the quarry. (TT, Vol. 2 at 189-90.) The road from the main gate led past the Model B and anybody who drove down the road could see the Model B in operation. (TT, Vol. 10 at 1749-55.) Indeed, it was the relatively open and uncontrolled nature of such plants that prompted Nordberg to request a provision in the test agreement discouraging third-party visits. (TT, Vol. 2 at 189-90.) Gieschen himself virtually lived at the Tanner facility and made efforts, to the extent possible, to keep third parties away from the Model B, especially during the early months of testing. (TT, Vol. 13 at 2339-52.) Yet, despite this contractual provision and Gieschen’s efforts, Nordberg’s own internal memoranda indicate that there was relatively “free visiting” by various dealer personnel early on, a fact confirmed by Nielson in his testimony. (Ex. 606; TT, Vol. 10 at 1748-55.) 44. The initial agreement made no mention of the crusher being offered for sale to Tanner or of any “try-buy” arrangement between Nordberg and Tanner. (Ex. 129.) To the contrary, the agreement expressly provided that the crusher would be removed from the plant at the conclusion of the field tests. (Id.) However, Nielson testified that he understood from the beginning that Tanner would be able to purchase the Model B at the conclusion of the field tests if it so desired. (TFOF at ¶ 93; TT, Vol. 10 at 1752-58.) 45. The Model B was set up at the Tanner facility in September, 1979 and the field tests began on September 24, 1979. (NFOF at ¶¶ 48, 51; Ex. 76.) Strain gauge tests and stress tests were performed on all of the major systems of the Model B. (NFOF at ¶ 54; Ex. 76.) This initial round of field tests was completed in May, 1980 and established the durability and commercial viability of the machine. (TT, Vol. 1 at 77-9; Ex. 75.) However, on April 25, 1980, Nordberg and Tanner executed an amendment to the initial testing agreement extending the testing period to September, 1980 and turning control and use of the Model B over to Tanner. (NFOF at ¶ 55; TT, Vol. 1 at 74-5; Ex. 130.) The amended agreement also gave Tanner a first option to purchase the Model B at the conclusion of the test period. (NFOF at ¶ 55; Ex. 130.) This is the first and only documentary proof of any “try-buy” arrangement between Tanner and Nordberg with respect to the Model B. All other terms and conditions of the initial test agreement, not altered by the amendment, remained in full force and effect. (Ex. 130.) 46. As a result of the field tests at Tanner, Nordberg made some minor changes to the Model B’s hydraulics which were eventually incorporated into the commercial Omni-cone crushers that embodied the claimed invention. (NFOF at ¶ 59.) Although Tanner decided against purchasing the Model B at the conclusion of the field tests, Nordberg management was convinced of the crusher’s commercial viability and began preparing a patent application, which was filed on October 14, 1980. (NFOF at ¶¶ 21, 61.) Nord-berg did not disclose the use of the Model B at the Tanner facility in its patent application or at any point during the initial prosecution. (TFOF at ¶ 168.) Nordberg made reference to the Tanner use in a declaration filed during the reexamination, but the declaration was submitted to antedate the Batch patent (FOF at ¶ 25) and not to disclose the potential public use of the Model B. (TFOF at ¶ 168.) B. Telsmith’s 1100F. 47.Robert Stafford, Telsmith’s current president, was employed by Jeffrey Manufacturing (“Jeffrey”) for 16 years before joining Telsmith in May, 1978. (TFOF at ¶ 58.) As discussed earlier, while at Jeffrey, Stafford was responsible for the manufacture and evaluation of a new crusher, under a license from a foreign manufacturer in Germany, which employed double-acting hydraulic cylinders to perform both tramp release and clearing. (TFOF at ¶ 58; FOF at ¶¶ 29-31.) Shortly before joining Telsmith in May, 1978, Stafford had the idea of combining the double-acting hydraulic cylinders and hydraulic circuit from the Jeffrey crusher with Tel-smith’s 1100E crasher, which used coil springs for tramp relief and had no mechanism for clearing. (TFOF at ¶¶ 58-59; FOF at ¶ 20.) There is no evidence that Stafford was aware of Nordberg’s Model B project at this time. (TT, Vol. 5 at 936-37.) 48. Immediately after joining Telsmith, Stafford circulated a June 27, 1978 memo reiterating his idea and attaching a copy of the Jeffrey hydraulic circuit and a brief description of how it worked. (TFOF at ¶ 59; NFOF at ¶ 116; Ex. 537.) The memo did not provide any other details of the proposed crusher and did not describe or depict how the hydraulic system would be mounted or connected to the crusher. (Id.) The new crusher was given the name “1100F”. (Id.) 49. The necessary design details and design drawings of the hydraulic circuit for the 1100F were finalized by December 18, 1978. (NFOF at ¶ 118; TFOF at ¶ 61.) Manufacturing drawings were completed by the spring of 1979 and fabrication began immediately thereafter. (TFOF at ¶ 62.) Assembly of the 1100F was completed in June, 1979 and shop-tested in early July, 1979. (NFOF at 11119; TFOF at ¶¶ 67-68.) The shop testing consisted of throwing chunks of tramp material such as wood and metal into the crusher to determine if the hydraulic relief system worked. (Id.) The clearing function was also tested at this time. (NFOF at ¶ 119.) The crusher operated satisfactorily and Stafford was convinced that it would work for its intended purpose. (TFOF at ¶ 68.) As designed, assembled and tested, the HOOF clearly contained all of the elements and limitations of the claims-in-suit. (TT, Vol. 8 at 1544-47.) 50. After the shop tests, in September, 1979, Telsmith held its “Agtec ’79” seminar in Lincolnshire, Illinois. (NFOF at ¶ 107; TFOF at ¶ 70.) “Agtec” is an annual seminar sponsored by Telsmith and attended by Telsmith dealers and sales personnel. (Id.) Admission to Agtec seminars was by invitation only and the attendees were a select group of Telsmith employees and top producing dealers. (NFOF at ¶ 107.) 51. It is clear that the 1100F was described in detail at Agtec ’79. (NFOF at ¶ 108; TFOF at ¶ 70.) It is also clear that many of the attendees, including many of the dealer representatives, visited Telsmith’s plant in Milwaukee after the conference and saw demonstrations of the 1100F. (NFOF at ¶¶ 108,112; TFOF at ¶ 71.) The demonstrations focused on the tramp relief and clearing mechanisms; no rock was actually run through the machine. (Id.) None of the dealers or the Telsmith employees in attendance were under any obligation of secrecy. (TFOF at ¶¶ 70-71.) 52. Most of the attendees who testified at trial stated that they believed and understood that the 1100F was on sale. (NFOF at ¶ 108; TFOF at ¶ 72.) One attendee stated in a deposition, however, that the machine was not ready for sale because it had not been tested in the field and that the only reason the 1100F was discussed and demonstrated was to introduce it as a machine that would be available some time in the future. (NFOF at ¶ 110.) None of the attendees testified that they approached a customer or solicited orders prior to the critical date of October 14, 1979. (NFOF at ¶108.) Tel-smith produced no brochures or other materials from this time frame promoting the new crusher or soliciting orders for the same. (Flora Dep. at 26.) In fact, a handout distributed at the seminar merely refers to the machine as a “pilot model crusher” being assembled on the erection floor and yet to be tested in the field. It does not give any indication that the machine was for sale or even encourage the attendees to seek orders for the same: 1100 “F” Style Gymsphere — The objective of this program was to provide an automatic adjusting feature while crushing, and incorporate a system through the use of hydraulics, which will permit the machine to pass tramp iron during the crushing operation. The automatic adjusting feature will utilize pneumatics for releasing the upper frame assembly and a modified version of our current power rotator will provide the means of rotating. Hydraulic cylinders, replacing the coil springs, will provide the downward force on the upper frame assembly during the crushing cycle and also serve as a tramp iron release mechanism. To achieve the above objectives, a pilot model crusher was built and is now being assembled on our erection floor. After extensive testing in our shop, plans have been initiated to field test the crusher at a local sand and gravel installation. (Ex. 572-A.) The only written notice to Tel-smith dealers announcing the availability of the HOOF and encouraging the solicitation of prospective buyers was dated April 23, 1980, well after the critical date of October 14, 1979. (Ex. 564.) 53.In May, 1979, prior to the Agtec conference, James Stibor of Telsmith approached Peter Clemmons of Crystal Lake Stone (“Crystal Lake”) about the possibility of placing the 1100F in Crystal Lake’s quarry for a field test. (NFOF at ¶ 97; TFOF at ¶ 65.) An agreement was reached and confirmed in a May 24, 1979 letter from Stibor to Clemmons. (Id.; Ex. 553.) The agreement referred to the 1100F as a “test machine” and an “experimental crusher”. (Ex. 553.) However, the parties understood the field test to be a “try-buy” arrangement wherein, at the end of the field test, Clem-mons could trade in his old 1100E and buy the 1100F if he was satisfied with its performance. (NFOF at ¶¶ 97, 99; TFOF at ¶¶ 65-66.) Although a specific price for the 1100F was not discussed at any time prior to the field test, Telsmith promised Clemmons that he would be offered a “good deal” on any purchase. (NFOF at ¶¶ 97, 99.) 54. Although the agreement was reached in May, 1979, the 1100F was not delivered to Crystal Lake until early November, 1979, which is after the critical date of October 14, 1979. (NFOF at ¶ 101; TFOF at ¶ 73.) The field test lasted only 3-4 weeks. (TT, Vol. 10 at 1780.) The 1100F tested well and Crystal Lake was satisfied with its performance. (TT, Vol. 10 at 1781-82, 1795-98.) Jake Smith of Telsmith then formulated a price for the 1100F on January 10, 1980. (NFOF at ¶ 100.) Clemmons decided against purchasing the machine, however, primarily because the -asking price was too high. (NFOF at ¶ 102; TFOF at ¶ 73.) 55. After the Crystal Lake field test, Tel-smith determined that more field testing was necessary before going into full production and therefore sought another location to place the 1100F for field tests. (Ex. 564.) Telsmith wanted the operator to agree to purchase the machine up front, however, with payments extended over the duration of the field test. (Id.) No such buyer was found and the 1100F sat in Telsmith’s inventory from 1979 until it was sold to an Alabama customer in 1983 or 1984. (NFOF at ¶ 104; TFOF at ¶ 75.) Telsmith never made another 1100F and did not commercially introduce the 1310 — another, modified hydraulic crusher — until 1987. (NFOF at ¶ 105.) V. PROSECUTION HISTORY OF 373 PATENT 56. As stated earlier, after the successful field testing of the Model B, Nordberg was confident of its commercial viability and filed a patent application. Giesehen’s original patent application was filed on October 14, 1980 and was assigned to Rexnord (Nordberg’s predecessor, hereinafter “Nordberg”) during prosecution. The application contained 31 claims, of which only five are at issue in the present lawsuit, i.e., claims 8-11 and 13. These claims were originally filed as application claims 19-25. Gieschen described these claims as providing a tramp release function as well as a clearing function, which operate in combination with a mechanical seat for positive positioning upon passage of tramp material (the abutting relationship). (NFOF at ¶ 69.) 57. On November 23,1981, Gieschen filed a Preliminary Amendment for the purpose of correcting typographical errors, and a Publication Statement in which he disclosed to the PTO several prior art patents (Polzin, Gilbert, Davis ’759, Gasparac ’342, Davis ’760, Johnson, Gasparac ’774, Szaj, Symons and Werginz) and a publication (Pegson-Telsmith Autocone Brochure). (NFOF at ¶71.) 58. On July 2, 1982, the Examiner issued an Official Action in which, among other things, claims 16 and 19-25 were rejected as being anticipated by, or obvious in view of, Gruender, a prior art patent. (NFOF at ¶ 72; Ex. 3 at 3089-92, 3098.) It was odd for the Examiner to group claim 16, which relates to a ram assembly mechanism for adjusting the bowl, with claims 19-25, which relate to the hydraulic tramp relief and clearing system. (TT, Vol. 4 at 738-39, 748-50.) In any event, Gruender discloses a conical crusher having single acting pneumatic cylinders for tramp release, but no mechanism for clearing. (NFOF at ¶ 73.) The Examiner reasoned that “[t]he exact manner in which the bowl is rotated and the exact manner in which the tramp release means is operated are both seen to be obvious matters of choice and structural design.” (Ex. 3 at 3098.) 59. On November 2, 1982, Gieschen filed an Amendment in response to the Examiner’s rejection, in which claim 19 (now claim 8) was amended to include specific references to the clearing function (“lifting means”) and claim 20 (also now claim 8) was amended to elaborate on the abutting relationship and to include the language regarding at least one accumulator to receive fluid displaced during tramp relief. (NFOF at ¶74.) Gieschen argued that no prior art, including Gruender, either alone or in combination, used double acting hydraulic cylinders to provide tramp release and clearing and the abutting relationship: Claim 19 calls for a crusher characterized by a release means which biases the upper and lower frames in an abutting relationship and allows the upper and lower frames to separate vertically to allow passage of tramp material through the crushing cavity. In addition, claim 19 has been amended to further restrict the release means to a double acting hydraulic cylinder which can be pressurized on the side opposite the tramp release side to raise the upper frame member off its seat to permit the crusher cavity to be cleared of jammed material. Gruender does not show a double acting cylinder which biases the upper frame against the lower frame in abutting relationship and then lifts the upper frame off the lower frame to permit the passage of jammed material. Neither does any other prior art of record in this application and, to applicant’s knowledge, this arrangement is absolutely novel and unobvious. It produces a particularly effective and efficient use of the structure by performing multiple functions with the same apparatus merely by use of various hydraulic connections and valving. It makes possible the automatic operation of the clearing function and also prevents the loss of hydraulic pressure when the tramp release mechanism is operating. It permits a very accurate indexing of the upper and lower frames by the abutting relationship and separates the wear compensation function which is performed by the adjusting ram separately so that the hydraulic system is not asked to control the spacing between the crushing surfaces in normal operations. In the circumstances, it would appear that claim 19 is patentable over Gruender and any other prior art of record in this application either alone or in combination. (TFOF at ¶ 15; Ex. 3 at 3130-31.) 60.In a second Official Action, dated January 26, 1983, the Examiner rejected claims 16 and 18-25 as being obvious in view of a combination of Gruender and Kueneman et. al. (NFOF at ¶76.) Kueneman, another prior art patent, was cited for disclosing a crusher bowl adjustment mechanism. (Id.) The Examiner reasoned that “[i]t would be obvious in view of Kueneman et al to modify the Gruender device by providing a ram assembly for adjusting the bowl, and to provide the bowl with an annular surface having spaced abutments for contact with the ram assembly. The exact construction and operation of the ram assembly are seen to be obvious matters of choice and structural design.” (Ex. 3 at 3151.) In this the Examiner focused entirely on the adjustment mechanism of the crusher, detailed in application claims 16-18, which clearly had nothing to do with the hydraulic system detailed in application claims 19-25. (TT, Vol. 4 at 748-50.) Nothing in the Examiner’s remarks related to the hydraulic system at all. (Id.) Charles Gholz, Nordberg’s legal expert at trial, described this omission as “bizarre” and the Court agrees. (Id.) One must conclude that the Examiner was either very confused or simply did not understand the claims-in-suit. 61.On July 26, 1983, Giesehen filed another amendment in response to the second rejection. The claims-in-suit were not amended. Rather, in the remarks section, Giesehen emphasized the fact that Gruender did not provide a clearing mechanism: Claim 19 and claims 1, 2, 27, 28, 33, 34, and 35 are all directed to a crusher having upper and lower frame assemblies which are biased into abutting relationship by release means and which can be forcibly separated by the release means to clear the crusher of jammed material. The reference relied upon to show the subject matter is Gruender, however, Gruender does not disclose a clearing function. Gruender’s piston and cylinder 214 and 213 are merely for the purpose of tramp release and are incapable of lifting the upper bowl assembly for clearing.... Since there is no prior art in the file or anywhere else known to Applicant which does meet these claim limitations and there is nothing in the prior art identified by the Examiner or known to the Applicant which would make the claimed combinations obvious to one skilled in the art at the time the invention was made, these claims should be allowable. (NFOF at ¶ 77; Ex. 3 at 3171-72.) Gies-chen’s remarks in this regard may not have been entirely forthcoming. That is, Giesehen states that nothing in the prior art of record disclosed double acting hydraulic cylinders that performed both tramp release and clearing. This is not true. The Autoeone brochure, cited by Giesehen in his Publication Statement, employed double acting cylinders, coupled with an accumulator, for both tramp release and clearing. (Ex. 3 at 3092; TT, Vol. 5 at 915-19; Ex. 4 at 3354-65; TFOF at ¶ 18.) The Autocone did not provide the abutting relationship between the two upper frames (Ex. 3 at 3092), but that was not the focus of Gieschen’s remarks above. In any event, neither Giesehen nor the Examiner ever discussed the Autocone brochure in the context of the claims-in-suit which, given its greater relevance than Gruender (which had single acting pneumatic cylinders and no clearing mechanism), is further evidence of the Examiner’s confusion. 62. On October 20, 1983, the Examiner issued a third and final Official Action in which the rejection of claims 16, 18-22, 25 and 35 was reiterated on the same confused grounds as before. (NFOF at ¶ 78; Ex. 3 at 3181; TT, Vol. 4 at 755-57.) 63. On February 6, 1984, Giesehen appealed this final action to the Board of Appeals and, in particularly strong language, pointed out the Examiner’s confusion regarding the claims-in-suit and the Gruender and Kueneman patents: Claim 19 calls for release means for biasing the crusher bowl against the frame for tramp release, and having lifting means connected between the upper and lower frames responsive to a first signal for deactivating the biasing means and activating the lifting means for lifting the upper frame away from the lower frame to permit the clearing of jammed material, and responsive to a second signal for activating the biasing means and deactivating the lifting means. This subject matter relates to the tramp release and crusher clearing system which is the double acting hydraulic cylinders 68 and the control system as shown in Figure 12 of the drawings. Claim 19 has been rejected on the combination of Gruender and Kueneman. Kueneman teaches a conventional spring biased tramp release system and a crusher cavity adjusting mechanism which rotates the bowl in the helical threads in the adjustment ring to control the gap of the crushing cavity. Gruender shows a pneumatic tramp release scheme which, essentially, is a gas spring, that is, a pneumatic equivalent of the spring release system shown in Kueneman. Neither Kueneman nor Gruender teach any of the structure set forth in the characterizing clause in Claim 19. In particular, they do not show an [sic] lifting means connected to the lower and upper frames for releasably biasing the upper frame into abutting relationship with the lower frame and responsive to a first signal for deactivating the biasing means and activating lifting means for lifting the upper frame away from the lower frame to permit the clearing of jammed material, and responsive to a second signal for activating the biasing means and deactivating the lifting means. In short, the citation of references applied against the claim does not anticipate or make obvious one single word of the characterizing clause. Applicant has carefully examined the two references for some interpretation which would have some relationship to the subject matter claimed in Claim 19 but can find nothing. The explanations set forth by the Examiner have no relation whatsoever to the subject matter. Applicant is utterly at a loss as to how to respond to this rejection since the references have a total absence of a biasing and lifting means which can be used as both a tramp release and a crusher clearing system. (NFOF at ¶ 79; Ex. 3 at 3218-3219.) (Emphasis supplied.) 64. Upon reviewing these arguments, the Examiner contacted Gieschen’s attorney by telephone and indicated that application claim 19 would be allowable if it incorporated the features of application claim 20. (NFOF at ¶ 80; Ex. 3 at 3229.) There is no indication how this proposed amendment addressed the Examiner’s prior objections. There is no explanation as to why this relatively minor change suddenly made the claims-in-suit patentable. In any event, Giesehen made the required changes and the patent issued on October 23, 1984. (NFOF at ¶80.) 65. As indicated earlier, Nordberg filed a Request for Reexamination of the claims-in-suit on June 6, 1989 in light of the 091, Webster and Batch patents. (Ex. 4 at 3154.) On January 30, 1990, the PTO issued a reexamination certificate for the 373 Patent, accepting Nordberg’s arguments distinguishing these three patents and stating that all of the claims were patentable as originally granted. (NFOF at ¶ 22.) VI. CLAIMS-IN-SUIT AND OPERATION OF 373 PATENT 66. As issued, the 373 Patent discloses a conical rock crusher having various features. However, for purposes of this suit, the technology at issue is the patent’s hydraulic tramp relief and clearing system. Specifically, the 373 Patent discloses double-acting hydraulic cylinders and pistons for both tramp relief and clearing. During normal crushing, these hydraulics also exert a hydraulic biasing force holding the upper and lower frames together in an abutting relationship. The abutment is created by complementary beveled surfaces. According to Nordberg, performing these three functions, ie., tramp relief, clearing and the abutting relationship, by means of a single hydraulic system, was Gieschen’s patentable advance or improvement over the prior art. Of the 27 total claims, this advance is disclosed in claims 8-11 and 13, hereinafter referred to as the “claims-in-suit”. (NFOF at ¶¶ 23-31, 64; TT, Vol. 3 at 489-90, Vol. 4 at 745-46.) 67. Independent claim 8 of the 373 Patent reads as follows: A crusher of the conical type having a stationary lower frame assembly, a vertically movable upper frame assembly biased toward said lower frame assembly, a head assembly including a crusher head mounted on a support means for gyratory motion relative to said frame assemblies, an adjustable bowl mounted to said upper frame assembly for vertical movement relative to said frame assemblies and head assembly and eccentric means for imparting gyratory motion to said head, and a drive means for driving said eccentric means, said crusher characterized by release means including biasing means and lifting means connected to said lower and upper frames for releasably biasing said upper frame into an abutting relationship with said lower frame and responsive to a first signal for deactivating said biasing means and activating said lifting means for lifting said upper frame away from said lower frame to permit the clearing of jammed material, and responsive to a second signal for activating said biasing means and deactivating said lifting means; said release means comprising a plurality of double acting hydraulic cylinders and pistons, said cylinders connected to one of said frame assemblies and said pistons connected to the other of said frame assemblies, one end of said cylinders being pressurized in a normally operating crushing mode to exert a hydraulic biasing force to hold said frame assemblies together in abutting relationship, and farther including at least one normally pressurized accumulator in fluid communication with said one end of said cylinders to receive fluid displaced from said cylinder when tramp material passes through the crushing cavity between said head and said bowl. (NFOF at ¶¶ 24-27; Ex. 1.) 68. Dependent claim 9 of the 373 Patent reads as follows: The crusher of claim 8 in which said piston is connected directly to the upper frame assembly and is biased downwardly by hydraulic pressure within said cylinder above said piston. (NFOF at ¶ 28; Ex. 1.) 69. Dependent claim 10 of the 373 Patent reads as follows: The crusher of claim 8 in which said one end of said cylinder communicates with said accumulator and, through a selectively movable valve, selectively with a hydraulic fluid reservoir and a hydraulic pressure source to vent said one end in a clearing mode for vertical separation of said frame assemblies, and to pressurize said one end in a normal crushing mode to bias said frame assemblies into abutting relationship, and the other end of said cylinder is selectively connected through said valve to said hydraulic pressure source in said clearing mode to lift said upper frame assembly away from said lower frame assembly, and to said reservoir in said normal crushing mode. (NFOF at ¶29; Ex. 1.) 70. Dependent claim 11 of the 373 Patent reads as follows: The crusher of claim 10 in which said valve means comprises a 4r-way, 3-position valve for selectively connecting the two ends of said cylinder with said source of hydraulic fluid pressure and said reservoir. (NFOF at ¶ 30; Ex. 1.) 71. Dependent claim 13 of the 373 Patent reads as follows: The crusher of claim 8, wherein said lower frame assembly includes an annular shell having an upper portion which terminates in a ring seat having a beveled upper surface; said upper frame assembly includes a ring having a beveled- lower surface corresponding to said ring seat upper beveled surface, said biasing means normally holding said ring against said seat with said beveled surfaces in contact with each other. (NFOF at ¶ 31; Ex. 1.) 72. The Court will not describe every facet of the operation of the 373 Patent. Rather, the Court will focus on the hydraulic tramp relief and clearing mechanism disclosed above, and specifically the hydraulic circuit used in that mechanism, as these matters are the focus of the parties’ dispute on the infringement issue. 73. To operate the crusher, one first has to charge the hydraulic circuit. (TT, Yol. 1 at 33-42; Ex. 601-G.) To charge the circuit, the gas-filled bladder contained in the accumulator 90 is charged to the desired pressure. (Id.) Then the pump 268 is started and causes oil to flow over line 236 until it reaches the valve 226, which is referred to as a 4-way 3-position valve. (Id.) Where the oil goes at that point depends upon the position of that valve. (Id.) When charging the circuit, the valve is shifted to the left and placed in the “crossover” position. (Id.) In this position the oil in line 236 enters valve 226, crosses over into line 2