Opinion for the court filed by Circuit Judge CLEVENGER.
Dissenting opinion filed by Circuit Judge NEWMAN.
CLEVENGER, Circuit Judge.Dorel Juvenile Group, Inc. (“Dorel”) sued Graco Children’s Products, Inc., (“Graco”) for patent infringement, seeking a jury trial. Dorel is the exclusive licensee of U.S. Patent No. 6,550,862 (“the ’862 patent”) and continuing U.S. Patent No. 6,612,649 (“the ’649 patent”), both directed to a ehild!s car seat assembly having a retractable cup holder. Graco conceded that its accused car seat embodies all of the elements of the asserted claims, except for certain aspects concerning the seat and base assembly, ie., a base removably attached to a seat.
On cross-motions for summary judgment, the United States District Court, for the Southern District of Indiana ruled for Graco and against Dorel, holding that under the -district court’s interpretation of the pertinent claim terms, Graco’s car seat does not infringe the ’862 and ’649 patents. See Dorel Juvenile Group, Inc. v. Graco Children’s Prods., Inc., No. 03-1273, 2004 WL 2269760 (S.D.Ind. Sept. 9, 2004) (“Summary Judgment ”). Dorel timely appealed the final judgment of the district court. Because there exists a question of fact as to whether Graco’s car seat infringes the patents, we vacate the district court’s summary judgment and remand the case for further proceedings.
I
Claim 1 of the ’862 patent covers a juvenile seat assembly comprising, inter alia, “a seat, and ... a base, the seat being removably secured to the base.” ’862 patent, col. 6, ll. 2-14. Claim 1 of the ’649 patent likewise covers a juvenile seat assembly comprising, inter alia, “a seat, *1045[and] a base removably attached and arranged to support the seat.” ’649 patent, col. 6,ll. 2-6.
Graco’s accused seat consists of two plastic parts. The top portion provides a relatively flat surface for a child to sit on, and the bottom portion is a structure upon which the top portion fits. The two parts are firmly held together by screws. In one iteration of the accused product, the screws are of the ordinary variety, removable with ease by use of a common screwdriver. In another iteration of the accused product, Graco uses so-called “one-way” screws. A one-way screw can be “screwed down” with an ordinary screwdriver, but a different type of screwdriver is required to loosen and remove the tightened screw. Ordinary screwdrivers and one-way screwdrivers can be purchased in hardware stores, among other places.
II
Upon granting Graco’s motion for summary judgment of noninfringement, Summary Judgment at 1 the district court first interpreted the terms “removably attached” and “removably secured,” id. at 5-6. Neither party argued that a specialized meaning of the terms existed in the art of juvenile ear seat design. The district court thus attributed to the terms their ordinary meaning and concluded that they require that the seat and base in the claimed invention “will be detached or unsecured on some occasion during the lifetime of the product.” Id. at 5. In other words, the district court determined that the claimed product is designed to come apart. The district court concluded, however, that the claim language does not require that the seat and base come apart during normal usage. Ease of separation is not a limitation on claim scope, as the district court opined, because the claim language does not recite “easily” removable or removable “relatively easily.” Id. at 6. Indeed, the district court expressly and emphatically rejected any notion that the claims require “ease of separation” of the seat from the base. “Removably attached” and “removably secured” mean only that the seat and base “are designed at some time or another to come apart.” Id. at 5.
The district court further opined that the claim terms “removably attached” and “removably secured” “carry with them an implication that the detachment or unse-curing process not do violence to the seat.” Id. The seat must therefore be usable as a seat upon separation from the base. In sum, the district court held that the claims cover a structure that includes a seat and base “affixed together in a manner that contemplates that the seat may be removed from the base such that the seat remains functional.” Id. at 6.
Turning next to the claim term “base” and to the surrounding claim language, the district court determined that the base is “the structure that props up the seat.” Id. Finally, the district court interpreted the claim term “seat” as “the structure intended to be sat in or on,” id., a structure the district court thought necessarily to be separate from the base.
The district court applied this construe-, tion to the accused Graco products and found no literal infringement because the accused products were found not to have a seat separate from .the base, as claimed in the asserted patents, and because the two parts of the accused products were found to be an integrated unit. Id. at 7. In short, the district court held that Graco’s two-part structure is integral, meaning that it lacks a seat and base as separate, stand-alone structures.
Ill
We review issues of claim interpretation independently, Cybor Corp. v. *1046FAS Techs., Inc., 138 F.3d 1448, 1456 (Fed.Cir.1998) (en banc), and test the scope of claim language with primary reference to the specification, of which the claims are a part, Phillips v. AWH Corp., 415 F.3d 1303, 1315-17 (Fed.Cir.2005) (en banc).
The district court correctly interpreted “removably attached” and “removably secured.” The specifications of the patents in suit are mainly directed to the claimed cup holder feature of the inventions, and there is little reference to the concept of the removability of the seat from the base. See ’862 patent, Abstract (“A juvenile vehicle seat is provided including a cup holder. The cup holder is movable between a retracted position adjacent the seat and an extended position spaced from the seat.”); ’649 patent, Abstract (same). The specifications speak of “means for coupling” the seat bottom to the base, but expressly state that such means are not shown in the drawings. ’862 patent, col. 2, ll. 52-53; ’649 patent, col. 2, ll. 55-56. Further, the “seat base is configured to releasably couple to the seat bottom.” ’862 patent, col. 1, ll. 27-29; ’649 patent, col. 1, ll. 31-33.
To impart “ease of separation” to the claims would require adding the words “easily” or “relatively easily” to the “removable” limitations, as the district court noted. Nothing in the patent’s specification suggests “ease of separation.” If anything, the specification teaches the meaning given to the “removable” limitations by the district court. This is so, because the only reference to what might be placed in the patented cup holder is shown in Figure 4 as a “COLA.” Given the configuration of the cup holder and the seat’s base, spilled cola would surely invade the bottom portion, where it could attract bees, hornets and other unwelcome insects. The occasional need to unscrew the top portion from the bottom portion to clean away spilled cola, or other matter that could find its way from the cup holder into the bottom portion, comports with the district court’s holding that the seat and base merely be capable of separation.
As the district court was no doubt aware, “ease of separation” is a common trait of many iterations of modern infant car seats. Simple observation on the public streets, of parents removing children from cars reveals two-part infant car seats, whereby the base portion remains in the car while the seat portion is removed with the child still strapped in. This seat portion can then be easily secured into an infant stroller and later removed from the stroller to be reattached to the base portion that had remained in the car. While this may be the preferable two-part car seat for use with infants, the patents in suit do not require that the seat be “easily removable” from the base. There simply is no reference whatsoever in the specifications to “ease of release” or “ease of separation,” no indication that the patent is directed to a product comprising á base that, during everyday usage, remains in the automobile while the user removes the seat and the child.
In short, the “removable” limitations, as understood through the plain meaning of the claim language and as tested by information in the specification, per Phillips, are just as the district court held. The seat and base can be separated “in a manner that contemplates that the seat may be removed from the base such that the seat remains functional.” Summary Judgment at 6.
The district court also correctly construed the terms “seat” and “base” to require two separate structures — “the structure intended to be sat in or on” and “the structure that props up the seat,” respectively. Id. The drawings in the pat*1047ents certainly confirm the district court’s understanding that the seat and the base are two separate structures held together by some means. See ’862 patent, Figs. 1-4; ’649 patent, Figs. 1-4. We thus discern no error in the district court’s interpretation of the key claim terms.
IV
We, however, take issue with the district court’s conclusion, on cross-motions for summary judgment, that the accused Graco juvenile car seat cannot infringe as a matter of law because it lacks a seat separate from a base and, at most, includes a base that is integral to the seat. See Nazomi Communications, Inc. v. Arm Holdings, PLC, 403 F.3d 1364, 1367 (Fed. Cir.2005) (“A summary judgment motion is proper if there are no genuine issues of material fact, while viewing the facts in a light most favorable to the non-moving party.”). The district court has invaded the province of the finder of fact, here a jury requested by Dorel, in deciding the infringement question. See Bai v. L & L Wings, Inc., 160 F.3d 1350, 1353 (Fed.Cir. 1998) (stating that the “determination of infringement, whether literal or under the doctrine of equivalents, is a question of fact”).
The accused products comprise a top structure and a bottom structure, each easily removable from the other by an ordinary or one-way screwdriver, such that they are “removably attached” or “removably secured”. However, whether the top and bottom structures of the Graco products are in fact the claimed “seat” and “base” of the asserted patents, such that the top structure is capable of functioning as a “seat” upon being removed from the bottom structure, is a question of fact that cannot be determined on summary judgment. We therefore vacate the summary judgment of noninfringement and remand the case to the district court to determine, as a matter of fact, whether the accused products meet the seat and base limitations of the asserted claims, and to decide any remaining issues.
VACATE AND REMAND