Neapco Drivelines v. American Axle & Manufacturing (Fed. Cir. 2021)
This is a sister case to the one pending before the U.S. Supreme Court regarding eligibility of the claims of American Axle’s U.S. Patent No. 7,774,911. That case is at the petitions stage and is awaiting responsive briefing from Neapco.
In this case, American Axle challenged Neapco’s vented slip-joint coupling Patent No. 5,772,520 via Inter Partes Review. The PTAB found claim 11 anticipated and its depdendent claim 12 obvious in light of the prior art — primarily Burton (U.S. Patent No. 5,655,968). On appeal, the Federal Circuit has affirmed.
Neapco’s ‘520 patent was originally owned by Ford Motor Co. Ford sold the patent as part of an overall sale of Ford’s driveshaft unit to Neapco back in 2008. The patent expired back in 2016, but Neapco still sued American Axle in 2017 seeking back damages. That case is stayed pending outcome of the IPR.
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The claims at issue here are directed to what appears to be a method of assembling the vented slip-joint for a vehicle driveshaft, although it is expressly claimed as a “method of venting a slip joint assembly.” The slip-joint looks like a hydraulic shock-absorber and is designed to allow some axial compression of the driveshaft while still transmitting torque. Neapco’s patent just has air inside the assembly (not hydraulic fluid), and the “venting” innovation here allows for compressed air to escape while keeping-out debris.
The key debate in this case is whether the prior art discloses (Burton) venting. The prior art shaft – shown in figure 3 above – includes a “passage 130” that allows fluid communication from inside the slip assembly’s two operational main parts (stud yok and slip yok) to a third chamber within the assembly.
The patentee first argued that its claim should be interpreted as requiring venting to the outside (not internal venting). On appeal, the Federal Circuit found that the claim language did not support such a construction, and rejected the patentee’s argument to give effect to an implicit requirement found in the preamble.
Neapco also argued that the function of its valve was pressure relief — something not provided by Burton. ON appeal again, the court found that the claims did not require pressure relief, only a venting out of the main operational chambers.