Declaratory judgment defendant-appellant, La Gard, Inc. (“La Gard”), appeals the decision of the United Stated District Court for the Eastern District of Kentucky holding after a bench trial that United States Patent No. 5,307,656 (the “ ’656 patent”) was not shown infringed by declaratory-plain-tWcross-appellant Mas-Hamilton Group’s (“Mas-Hamilton’s”) X-07 lock.
See Mas-Hamilton v. La Gard, Inc.,
No. 94-349, slip op. at 74,
BACKGROUND
The ’656 patent is entitled: “High Security Electronic Dial Combination Lock.” Figure 1 from the patent has been reproduced below, and description of the disclosed lock will be made with reference to this figure. The electronic combination lock 20 includes a locking mechanism or bolt 36 for operating between a locked condition and an unlocked condition, a rotatable cam wheel 47 having a circumferential surface portion defining a slot 88 such that the rotation of the cam wheel moves the slot, and a movable lever 46 coupled to the locking mechanism for changing the condition between locked and unlocked. The movable lever can be pivoted out of engagement with the cam wheel. When the movable lever engages the cam wheel, rotation of the cam wheel changes the condition of the locking mechanism. A cantilever arm 52 and detent 54 on the lever releasably maintain the lever in a position disengaged from the cam wheel. A solenoid 1 and projectable detent 96 move the lever from its disengaged position to a position engaging the cam wheel thus changing the locking mechanism from the locked condition to the unlocked condition. ’656 pat., col. 7,1. 4 — col. 8,1. 24.
[[Image here]]
The accused Mas-Hamilton X-07 lock also utilizes, inter alia, a cam wheel including a slot, a movable lever and a cantilever arm. The X-07 lock, however, uses a stepper motor instead of a solenoid to provide power to rotate a partial gear through a complex series of intervening rotatable and pivotable cam members to cause a vertical translation of a slide member to move the lever.
In August 1994, La Gard charged Mas-Hamilton’s X-07 lock with infringing the ’656 *1210 patent. In September 1994, Mas-Hamilton sought declaratory judgment that the accused lock does not infringe the ’656 patent. La Gard counterclaimed for infringement of the ’656 patent in July 1995, and in response, Mas-Hamilton asserted affirmative defenses that the ’656 patent is invalid and not infringed. In February 1997, the case was tried to the court, and in a seventy-six page opinion, the district court held the ’656 patent not infringed and not invalid. La Gard appeals the determination of no infringement with respect to asserted claims 1, 3, 31, 34, and 43, and Mas-Hamilton cross-appeals the determination that the patent-in-suit is not invalid. This appeal was submitted for our decision following oral argument on July 1,1998.
We hold that the district court did not clearly err in its noninfringement determination because the accused X-07 lock lacks the “lever operating means” required in asserted claims 1, 3 and 31, and the “movable link member” required in asserted claims 34 and 43. We therefore affirm the district court’s finding of no infringement of the ’656 patent. Further, because the district court did not err in determining that none of Mas-Hamilton’s invalidity theories was proven meritorious, we also affirm the district court’s holding that the ’656 patent is not invalid.
DISCUSSION
I. Jurisdiction
Before discussing the merits of this appeal, we must first rule on Mas-Hamilton’s pending motion to dismiss the appeal for lack of jurisdiction.
Mas-Hamilton argues that this court lacks jurisdiction over the present appeal because La Gard and Masco Corp. (“Masco”) (La Gard’s successor-in-interest to the patent-in-suit) each lack sufficient ownership interest in the ’656 patent to confer standing. According to Mas-Hamilton, the assignment of title in the ’656 patent was silent with respect to the right to sue for past infringement; consequently, only the owner of the patent at the time of the infringement can bring an action for damages resulting from that infringement. Mas-Hamilton asserts, therefore, that La Gard does not have standing to pursue the appeal because it no longer retains an interest in the ’656 patent, and Mas-co lacks standing because, although it currently owns title to the ’656 patent, it did not have title at the time the alleged infringement took place because La Gard did.
Mas-Hamilton relies on
Crown, Die & Tool Co. v. Nye Tool & Machine Works,
In the instant case, when Mas-Hamilton filed its declaratory judgment action against La Gard, La Gard was the owner of the ’656 patent. Title to the patent was not transferred until October 21, 1997, after the present appeal was filed. Hence, as required by the above-cited cases, the holder of title to the patent at the time of the infringement brought the action. Further, there is no dispute that Masco is the assignee of the ’656 patent and not a mere licensee.
In Arachnid, the court repeated the warnings of Supreme Court cases:
[t]he exception [to the rule that the plaintiff must be the person in whom title to the patent resided at the time of the infringement] is where the assignment of a patent is coupled with an assignment of a right of action for past infringements. The authorities are uniform that the latter assignment must be express, and cannot be inferred from the assignment of the patent itself.
Arachnid,
While it is true that in
Enzo,
we held that “nunc pro tunc assignments are not sufficient to confer
retroactive
standing,”
Further, in
Enzo,
this court had to determine whether an oral exclusive license in combination with a later
nunc pro tunc
written license could confer standing without the holder of the title being joined. We held that it could not.
See Enzo,
II. Infringement
A patent infringement analysis involves two steps. First, the court determines the scope and meaning of the asserted claims.
See Markman v. Westview Instruments, Inc.,
Claim limitations drafted pursuant to 35 U.S.C. § 112, ¶ 6 are termed means-plus-function limitations. Section 112, ¶ 6 provides that such limitations “shall be construed to cover the corresponding structure ... described in the specification and equivalents thereof.” “The ‘means’ term in a means-plus-function limitation is essentially a generic reference for the corresponding structure disclosed in the specification.”
Chiuminatta Concrete Concepts v. Cardinal Indus., Inc.,
The second step in the infringement analysis requires a comparison of the claims to the accused device.
See Cybor,
For literal infringement of a section 112, ¶ 6 limitation, the fact-finder must determine whether the accused device performs
*1212
an identical function to the one recited in the means-plus-function clause.
See Pennwalt,
Determination of infringement under the doctrine of equivalents requires the fact-finder to determine whether the structural differences between the particular elements of the accused device and the asserted claim’s limitations as recited in the claim and as shown in the corresponding means structures in the specification are insubstantial.
See Warner-Jenkinson Co. v. Hilton Davis Chem. Co.,
A. Independent Claims 1, 3, and 31
Claim 1 requires, inter alia:
lever operating means for positively driving said lever toward said cam in response to continued dial rotation after said combination has been entered,....
’656 pat., col. 8,11. 45 (emphasis added). The parties do not dispute that this claim limitation is in means-plus-function format. See 35 U.S.C. § 112, ¶ 6.
Looking to the specification to determine the structure that the inventor intended to perform the specified function, i.e., positively driving the lever toward the cam, we note that the “lever operating means” includes, at least, a solenoid, spherical detent 96, solenoid housing 62, boss 92, and pin 54. See Fig. 1, ante. A solenoid is an electrically energized coil of insulated wire which produces a magnetic field within the coil to provide power. See McGrauw-Hill Dictionary of Scientific and Technical Terms 1863 (Sybil P. Parker ed., 5th ed.1994). In operation, the solenoid is actuated to move a plunger 98 to its rightmost position. As the plunger is moved to the right, it causes spherical detent 96 to ride up the head of the plunger. The spherical detent is then exposed above the top of the solenoid housing 62. As the cam wheel continues to rotate, the boss 92 pushes the spherical detent and therefore the solenoid housing, including recess 58, against the bias of spring 112. The pin 54, located in the recess 58, and the cantilever arm 52 move so that the lever 46 pivots until the nose part 48 engages the slot 88 on the cam wheel. At that point, continued linear translation of the solenoid housing causes the pin in the cantilever arm to ride up the ramp surface 60 and onto the outside of the solenoid housing. In order to relock the lock, the dial can be turned in the opposite direction and the process, in essence, is reversed. See ’656 pat., col. 7,1. 4—col. 8,1. 24. The solenoid, therefore, is a required structure for the “lever operating means” because it provides the power that operates the lever.
Next, the trier of fact compares the accused device with the structure disclosed in the specification corresponding to the means-plus-function limitation.
See Pennwalt,
Similarly, under the doctrine of equivalents, if the accused X-07 lock performs a substantially different function or performs in a substantially different way or obtains a substantially different result, it does not infringe claim 1.
See Engel Indus., Inc. v. Lockformer Co.,
Claim 3 requires, inter alia:
a substantially non-resilient lever moving element for moving the lever from its disengaged position for engaging the protrusion of the lever with the cam surface on the cam wheel so that the rotation of the cam wheel thereafter in the given direction changes the locking mechanism from the locked condition to the unlocked condition; ....
’656 pat., col. 9,1. 64 — col. 10,1. 2 (emphasis added). The district court determined that this claim limitation, although not reciting the term “means for,” is in means-plus-function format and therefore must be interpreted using section 112, ¶ 6.
See Mas-Hamilton,
La Gard asserts that the “lever moving element” should not be construed as claimed in means-plus-function format because it does not employ the catch phrase “means for.” La Gard relies on
Greenberg v. Ethicon Endo-Surgery, Inc.,
Although such a presumption is helpful in beginning the claim construction analysis, it is not the end of the inquiry. In the instant case, even though the catch phrase is not used, the limitation’s language does not provide any structure. The limitation is drafted as a function to be performed rather than definite structure or materials.
See
35 U.S.C. § 112, ¶ 6;
Chiuminatta,
La Gard asserts that a “lever moving element” is a known structure in the lock art, but the district court determined otherwise. While true that “[m]any devices take their names from the functions they perform,”
Greenberg,
In addition, in Greenberg, we emphasized that:
section 112(6) is triggered [not] only if the claim uses the word “means.” The Patent and Trademark Office has rejected the argument that only the term “means” will invoke section 112(6), see1162 O.G. 59 N. 2 (May 17, 1994), and we agree, see Raytheon Co. v. Roper Corp.,724 F.2d 951 , 957,220 USPQ 592 , 597 (Fed.Cir.1983) ... (construing functional language introduced by “so that” to be equivalent to “means for” claim language).
In the instant case, the claimed “lever moving element” is described in terms of its function not its mechanical structure. If we accepted La Gard’s argument that we should not apply section 112, ¶ 6, a “moving element” could be any device that can cause the lever to move. La Gard’s claim, however, cannot be construed so broadly to cover "every conceivable way or means to perform the function of moving a lever, and there is no structure recited in the limitation that would save it from application of section 112, ¶ 6.
See Cole,
Thus, we hold that the district court was correct in applying section 112, ¶ 6 to limit the “lever moving element” to structures disclosed in the specification and equivalents thereof that perform the identical function.
Referring to the specification to identify the corresponding structure that performs the specified function, we construe the “lever moving element” to include at least the solenoid that provides the power to move the lever. ’656 pat., col. 7, 1. 24 — col. 8, 1. 7. As already discussed with respect to claim 1, the X-07 lock uses a stepper motor instead of a solenoid. The stepper motor is not the structural equivalent of the solenoid and hence the “substantially non-resilient lever moving element” limitation is not met. We therefore hold that the accused X-07 lock does not literally infringe claim 3 of the ’656 patent. Similarly, we conclude that the accused X-07 lock does not equivalently infringe claim 3 of the ’656 patent because, under the analysis applied with respect to claim 1, it was not clear error for the district court to determine that the solenoid of claim 3 operates in a substantially different way than the stepper motor of the X-07 lock.
Claim 31 also requires “a lever moving element.” ’656 pat., col. 16, 1. 65. Hence, under the above analysis, the district court did not clearly err in determining that claim 31 is neither infringed literally nor under the doctrine of equivalents. We therefore affirm the district court’s finding of no literal or equivalent infringement of claim 31 by the X-07 lock.
B. Independent Claims 34 and 43
Claims 34 and 43 both require, inter alia:
a movable link member for holding the lever out of engagement with the cam surface before entry of a combination and for releasing the lever after entry of the combination;
’656 Pat., col. 17,11. 45-48, col. 18,11. 51-54. The district court construed this limitation under section 112, ¶ 6 as in means-plus-function format.
Mas-Hamilton,
La Gard argues on appeal that the district court erred in interpreting this claim limitation under section 112, ¶ 6. According to La Gard, the district court erred by considering the claim term “movable” to invoke section 112, ¶ 6. We agree with La Gard that the claim term “movable” alone does not cause the claim to be read in means-plus-function format. However, we note that the subsequent functional language requires two functions: (1) “for holding the lever out of engagement with the cam surface before entry of a combination,” and (2) “for releasing the lever after entry of the combination.” Such language is precisely what was intended by the statutory phrase in section 112, ¶ 6 requiring that means-plus-function limitations provide “a specified function.” 35 U.S.C. § 112, ¶ 6. Further, we do not see that the remaining terms in the claim limitation other than those defining the two functions, ie., “a movable link member,” provide any structure as necessary to remove this limitation from the ambit of section 112, ¶ 6. We hold, therefore, that the district court’s statement that the term “movable” caused section 112, ¶ 6 to apply, is at most harmless error because the limitation at issue was properly construed in means-plus-function format.
Referring now to the specification to determine the corresponding disclosed structure and equivalent structures for the “movable link member,” we note that the lever 46 is held out of engagement with the cam 47 by the arrangement of the cantilever arm 52 located in detent 54, and that upon entry of the correct combination, the solenoid housing 62 is moveable to the right which raises the cantilever arm 52 out of the detent 54 and causes it to travel on top of the solenoid housing. The lever is then released to come into contact with the cam. See ’656 pat., col. 7, 11. 40-62. Hence, the disclosed structure performs both functions of “holding” and “releasing.”
In its infringement analysis, the district court determined that the corresponding structure of the X-07 lock did not meet the second required function of releasing the lever after entry of the correct combination.
See Mas-Hamilton,
Q. With respect to the movable link member of Claim 34, is it correct that in the portion of the X-07 lock that you have identified with the movable link element of Claim 34, no part of the stud which projects from the rear face of the lever is releasable from the channel in the slide and no part of the lever is released by the slide or slide member movement after entry of the combination?
A. Yes.
Transcript of Trial, at 127-28 (Feb. 7, 1997). We do not find reliance by the district court on this testimony to be reversible error.
See Glaxo, Inc. v. Novopharm, Ltd.,
III. Validity
Mas-Hamilton argues on cross-appeal that the asserted claims of the ’656 patent are invalid for a litany of reasons: (1) on-sale bar, (2) public use, (3) best mode, and (4) invention by another.
Under 35 U.S.C. § 282, a patent is presumed valid and one challenging its validity bears the burden of proving invalidity by clear and convincing evidence.
See Innovative Scuba Concepts, Inc. v. Feder Indus., Inc.,
The ultimate determination of whether an invention was on-sale within the meaning of 35 U.S.C. § 102(b) is a question of law which we review
de novo. See Pfaff v. Wells Elec., Inc.,
The application that led to the ’656 patent was filed on December 17, 1990. Hence, before the district court, Mas-Hamilton had to prove by clear and convincing evidence that there was a definite, sale or offer to sell prior to December 17, 1989, and that the subject matter of the sale or offer to sell fully anticipated or rendered obvious the claimed invention.
See Mahurkar v. Impra, Inc.,
Mas-Hamilton asserts that the instant factual scenario more favors finding an on-sale bar than that presented in Pfaff in which this court held that the device embodying the asserted claims in the patent-in-suit was on sale prior to the critical date and reversed the district court. See id. at 1431, 43 USPQ2d at 1929. In Pfaff, verbal and written purchase orders were both received before the critical date, and the parties had a definite agreement before the critical date. See id. at 1432, 43 USPQ2d at 1930. Furthermore, in Pfaff, there were no facts in dispute, leaving only the legal issue of whether section 102(b) invalidates the patent. See id. at 1433, 43 USPQ2d at 1931. Finally, there was no doubt in Pfaff that what was offered for sale was the device of the later-issued patent.
By contrast, in the instant case, the parties dispute the primary factual issue — that is, whether Mosler was merely a potential licensee of legal rights, or, rather, a potential customer of devices. The district court found that Mosler was only a potential licensee.
Cf. Moleculon Research Corp. v. CBS, Inc.,
Mas-Hamilton asserted before the district court, and argues here, that a November 1989 meeting between officials from La Gard and Mosler constituted placing the lock of *1217 the ’656 patent on-sale. According to Mas-Hamilton, the purpose of the meeting was to obtain a contract for ten locks. La Gard argues, however, that the November meeting was solely to interest Mosler in a license under the patent and further that no deal was struck until after the critical date.
The district court found, based on the testimony given, that La Gard presented a prototype to Mosler and offered to furnish additional prototypes that were essentially the same device described in the ’656 patent. However, the district court farther found that the devices were for testing or show, only, and did not represent commercial sales of the lock even though money changed hands. Moreover, the district court also found that La Gard’s offer to Mosler was only an offer of either (1) production rights in the invention, or of (2) the exclusive right to market the invention to the government; neither of which involved a sale or an offer to sell the devices themselves.
Mas-Hamilton,
Furthermore, the testimony also indicated that Mosler (who in 1989 initially contacted La Gard about making a lock that satisfied certain government specifications) provided a purchase order that was never filled, and that no agreement was reached about the particulars of the proposed lock prior to the critical date. From the record, therefore, we do not discern clear error in the district court’s finding that there was not a definite sale or offer for sale of the locks later claimed in the patent. Hence, we affirm the district court’s conclusion that the ’656 patent was not invalid based on the on-sale bar.
Because we hold that the district court did not clearly err in determining that Mas-Hamilton failed to meet its burden that the ’656 patent was invalid under any of the above-listed theories, we affirm the district court’s holding that the ’656 patent was not shown invalid. We only address the on-sale bar issue because we find no merit in any of Mas-Hamilton’s other contentions regarding invalidity.
CONCLUSION
We hold that the district court did not clearly err in determining that the accused Mas-Hamilton X-07 lock does not infringe, either literally or equivalently, any of the asserted claims of the ’656 patent which are the subject of this appeal. We also hold that the district court did not clearly err in determining that the ’656 patent was not shown invalid by clear and convincing evidence by proof presented by Mas-Hamilton. As to both appeal and cross-appeal, therefore, we
AFFIRM.
COSTS
Each party shall bear its own costs.
Notes
. The solenoid is not shown in Figure 1, but it is located inside the solenoid housing 62.