Larami Corp. v. Amron
27 U.S.P.Q.2d 1280 (1993)
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Rule of Law:
For a product to infringe a patent claim, it must contain every element of the claim, either literally or through a substantial equivalent. A product does not infringe if even one element of the patent's claim is missing from the accused device.
Facts:
- Gary Esposito invented a toy water gun that used an air pump to pressurize water and was granted U.S. Patent No. 4,239,129 ('129 patent).
- The '129 patent's claims described the toy as having a water tank (chamber) located 'therein' an elongated housing or 'in the barrel' of the toy.
- The '129 patent also included various electrical features to illuminate the water stream and create noises.
- Alan Amron and Talk to Me Products, Inc. (TTMP) acquired the '129 patent by assignment from Esposito.
- Larami Corporation manufactured and sold a line of toy water guns called 'SUPER SOAKERS.'
- SUPER SOAKERS used a hand-operated air pump to pressurize water, similar to the mechanism in the '129 patent.
- However, the SUPER SOAKERS featured a detachable water reservoir located prominently outside and above the main body of the gun and had no electrical components for light or sound.
- TTMP alleged that Larami's SUPER SOAKER guns infringed on the '129 patent.
Procedural Posture:
- Larami Corporation filed a lawsuit against Alan Amron and Talk to Me Products, Inc. (TTMP) in the U.S. District Court for the Eastern District of Pennsylvania.
- Larami sought a declaratory judgment that its SUPER SOAKER guns did not infringe TTMP's '129 patent.
- TTMP filed a counterclaim against Larami, alleging patent infringement.
- Larami moved for partial summary judgment, asking the court to rule as a matter of law that its products did not infringe the '129 patent.
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Issue:
Does a toy water gun with an external, detachable water tank infringe, either literally or under the doctrine of equivalents, on a patent that explicitly claims a water tank contained 'therein' or 'in the barrel' of the toy's housing?
Opinions:
Majority - Reed, J.
No. A toy water gun with an external, detachable water tank does not infringe on a patent that explicitly claims a water tank is contained 'therein' or 'in the barrel' of the toy's housing, either literally or under the doctrine of equivalents. For literal infringement of Claim 1, the SUPER SOAKER fails because its water tank is external, not 'therein' the housing as the claim requires. The absence of even one element of a claim means there can be no literal infringement. For infringement under the doctrine of equivalents of Claim 10, the external tank is not a substantial equivalent of the internal tank. The external design offers significant functional advantages—such as simpler manufacturing, easier refilling, larger capacity, and replaceability—that are not mere 'unimportant and insubstantial' changes. The external tank functions in a very different manner, thus failing the test for equivalence.
Analysis:
This decision highlights the critical importance of precise claim language in patent law and places a clear boundary on the expansive reach of the doctrine of equivalents. The court emphasizes that the doctrine cannot be used to protect a general concept (a pressurized water gun) but only the specific invention as claimed. By finding that significant functional improvements (like the external tank) create a different 'way' of operating, the ruling protects subsequent innovators who improve upon prior art without copying the patented elements. This reinforces that competitors can 'design around' a patent by making meaningful, non-equivalent changes.
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