US 5349502

I'll verify against live sources and check for any litigation/docket activity, then summarize.

US 5,349,502 — Verification and Summary

Sourcing note: I retrieved the full text and bibliographic record of US 5,349,502 from Google Patents (https://patents.google.com/patent/US5349502/en), corroborated by the USPTO/Google patent PDF (US5349502.pdf) and FreePatentsOnline (FreePatentsOnline.com/5349502.html). I found no CAFC 2026 docket activity, IPR, or litigation involving 5,349,502 in live search. That is consistent with the record: the patent lapsed in 1998 for non-payment of maintenance fees, roughly 29 years ago, so no current enforcement docket is expected.

One caution on search results: several hits surfaced by the number search are actually documents from the earlier 3M family (EP 0428384 / CA 2026976 / US 4,994,939), which share nearly identical abstract language but describe a lattice whose half-shells are "permanently pinned and bonded together." That is the parent disclosure. US 5,349,502 is the later improvement that expressly avoids the need for bonding. Do not conflate the two.

Bibliographic data

Abstract (as issued)

"A universal lattice assembly for use in a magnetic-type electronic article surveillance system is disclosed which comprises a frame formed of two identical molded plastic half-shells, a metal chassis within which specific electronic sub-assemblies may be positioned and a coil assembly including a field-producing coil and a detector coil. The frame includes a substantially continuous series of tabs and notches which are positioned to be inter-connected as the half-shells are pressed together, the resulting assembly becoming dimensionally rigid, thus firmly anchoring a coil assembly in place, preventing any relative movement as the assembled unit may be jostled in operation."

Plain-language overview of the independent claim

Claim 1 is the sole independent claim; claims 2–16 all depend (directly or indirectly) from it. In plain terms, it covers a universal EAS pedestal ("lattice") built from three cooperating parts:

1. A structural chassis — a metal base having a bottom section secured to a floor-mounted base, opposing parallel side sections at the ends of that bottom, plus indexing/interlocking features for joining the chassis to other components.
2. A coil assembly — comprising a drive (field-producing) coil and a detector coil.
3. A frame of two identical molded half-shells — when mated, the shells define: (i) opposing spaced-apart vertical legs; (ii) a top section spanning the legs; (iii) a middle section between the legs, above the frame bottom; (iv) at least one additional section between the top and middle sections; and (v) a centermost vertical section connecting the top, additional, middle sections and the frame bottom. These sections define a connected interior cavity running through all of them, with structure inside for receiving and anchoring the coil assembly.

The claim's distinguishing feature is the attachment mechanism and resulting rigidity: a plurality of interlocking tabs and notches around a major portion of each half-shell's periphery, mating when the shells are pressed face-to-face, plus structure below the frame bottom for receiving electronic sub-assemblies and mating with the chassis. The chassis-to-frame mating produces a composite lattice "of a strength suitable for use in a hostile-user environment without requiring additional bonding of the chassis and the half-shells." That negative limitation is the express point of departure from the earlier bonded-lattice art (US 4,994,939 / EP 0428384).

Dependent claims (brief map)

• 2–4: Foot pad with floor mounting and chassis anchoring; a pair of upstanding support pins received in chassis apertures; unequal-length pins (one ~4 in shorter) enabling temporary positioning and testing of electrical null before permanent floor attachment.
• 5–6: Coil geometry — at least a pair of coplanar coil segments with vertical arms, top sections at different predetermined heights (anchored in different frame cavities), and bottom diagonal sections anchored in the middle-section cavity at opposing diagonal angles.
• 7–9: Arched top frame section with the detector coil's top section anchored above the drive coil; detector coil in a lazy figure-8 configuration with two crossed-over centermost vertical sections anchored in the centermost frame section.
• 10–12: Structural brace interconnecting two lattice assemblies; raceway in the brace for cabling; removable shims/spacers so the brace can be rigidly coupled during installation and then isolated to prevent walk-by vibration from shifting the electrical balance.
• 13–14: Electronic circuit(s) secured to the middle section; bulky components in an expanded housing on the non-corridor side to keep the corridor side flush.
• 15–16: Cavity parallel to the outer walls so the field-producing coil sits directly against the outer wall, maximizing effective interrogation-zone width; anchoring ribs defining tapered recesses (for wedging coils) and saddles (for resting coils).

Uncertainty / drafting notes

• Claim 9 appears to contain an internal inconsistency in the issued text: it recites the detector coil's top section "anchored within a cavity extending above the cavity within which the top section of said detector coil is anchored." As issued, the two references point to the same element. Read in light of the specification and claim 7, the intended comparison is almost certainly the field-producing coil's cavity. I am flagging this literally rather than correcting it, per the interpretive rules.
• Claim 1 uses "means for indexing and interlocking" and "means ... for receiving and anchoring," which are functional/means-plus-function style recitations. The corresponding structure is disclosed in the spec (ribs 94, tapered recesses and saddles, chassis flanges 64–70) but no § 112(f) construction has been litigated, since the patent expired in 1998.
• No claim construction, PTAB, or court record exists for this patent in any source I retrieved. Any statement about how the claims would be construed is inference from the specification, not authoritative adjudication.
• The "3M Co" current-assignee listing and the 2018 "patent discontinuation" status entry are administrative artifacts of the 1998 fee lapse, not a reassignment.

Bottom line: US 5,349,502 is a 1993-filed, 1994-issued 3M patent (Westerberg & Brace) on a modular, bond-free EAS pedestal frame formed from two identical interlocking molded half-shells over a metal chassis, with a single independent claim covering the chassis + drive/detector coil assembly + interlocking frame combination. It is long expired for failure to pay maintenance fees and has no 2026 judicial or PTAB activity.