Descent I · Hermetic Packaging & Feedthroughs · 1993-1996
1993: The First Housing
Before a pacemaker can keep a heart in time it must first survive where it works: warm salt water, chloride ions, dissolved oxygen, a body that objects. This descent begins at the earliest patent in the corpus — the housing itself — and the question under every therapy: how do you close a box exactly once, and keep it closed for a decade?
- span1993-1996
- grants1
- lineSealing electronics inside the body
Specimen · the beating client · live
The machine watching the muscle it must not fail. Everything this housing does answers to a rhythm that never pauses to let it be serviced. Real-time CMR cine, J. Cardiovascular Magnetic Resonance, doi:10.1186/1532-429X-15-79, CC BY 2.0, via Wikimedia Commons.The origin pointT1 · from the patentUS5535097A
Filed November 23, 1993 — the earliest patent in the corpus, with David A. Ruben first on the inventor list. The subject could not be more foundational: the pacemaker's body itself — the hermetic housing, and the connector module that joins it to the lead running into the heart.
Set-piece · permeation · kb/physics
The Sealed Wall Water enters a sealed box two ways — a leak, or permeation straight through the wall itself, no crack required. P = D·S scores high on both terms in every polymer, and turns to nothing in a welded metal wall. One line of physics disqualifies plastic and commands the whole corpus.The problemT1 · from the patentUS5535097A
The background section is a compact history of pacemaker construction: discrete components potted in epoxy; then sealed metal cans. By the early '90s the standard was a "clam shell" — two halves butt-welded around the electronics, requiring weld-ring protection and separate plastic cups to position components. Many parts, many steps, many chances for error.
The principleT1 · from the patentUS5535097A
Redesign the enclosure so the parts locate themselves. Claim 1: a first enclosure portion with a planar lower interior surface and a stepped second interior surface; battery and circuit mounted adhesively; connections made by wire bonding (chip-industry technique, not hand-soldered wires); the feedthrough passing through the stepped surface; a second portion completing the hermetic seal. (The molded resilient shroud forming the connector module is the abstract's summary — in the claims it is claim 3's connector module "mounted to said circumferential edge surface.") Claimed result: "fewer components and fewer manufacturing steps," lower cost, and a "smooth, rounded contour" kinder to the tissue pocket it lives in.
Plain-English registerT3 · interpretationconfidence: high
Instead of building a box and then engineering trays to hold everything, shape the box's interior so each part has one obvious seat — then close the lid once. Fewer pieces, fewer welds, fewer ways to fail.
Specimen tray · a housing of 1993
A Medtronic pacemaker from 1993 — the very year of the first filing in this corpus — kept now under museum glass. Titanium can, welded rim, connector block: the anatomy this first patent redesigned from the inside. Medtronic Micro-Minix pacemaker (1993), Science Museum, London — The wub, CC BY-SA 4.0, via Wikimedia Commons.Measured influenceT1 · from the patentUS5535097A
Google Patents lists 100 citing patents — among the most-cited work in the corpus (only the accelerometer line's members rank higher) — meaning a hundred later inventions found this design foundational enough to cite as prior art.
Why it matters to the storyT3 · interpretationconfidence: high
Every theme of the next three decades is already present in this one 1993 filing: hermeticity as the prime constraint, manufacturability as a design input, borrowing microelectronics techniques into medical devices, and volume efficiency as mercy on the patient. The corpus doesn't wander — it deepens. This is the seed.
Set-piece note (for Presentation)T3 · interpretation
The natural opener for the whole site: the 1993 patent's line drawing of the housing assembling itself piece by piece — battery seating into its step, bond-wires arcing, lid closing — then the finished can slowly morphs through the decades into the miniaturized modern forms. Career in one shot.
Phosphor plates · the drawings, inverted into the dark
The plate · US 5,535,097 · FIG. 4
A perspective assembly view with the lid half pulled away from the main shell, exposing the connector hardware between them — the connector block, setscrew, spring contact, feedthrough pin, and sealing plug all floating in their positions like a freeze-frame of the device being put together. US patent drawing — public domain.
Plate II · US 5,535,097 · FIGS. 1-3
Three plain outline views of the finished pacemaker can — front, back, and razor-thin edge-on — establishing its rounded D shape, the connector bore at the top corner, and the feedthrough spot on the rim. US patent drawing — public domain.
Plate III · US 5,535,097 · FIG. 5
The open main shell viewed from above with the lid removed, showing the stepped interior ledge along the top edge where the feedthrough and connector parts seat themselves — the self-locating geometry at the heart of the claim. US patent drawing — public domain.
Plate IV · US 5,535,097 · FIG. 6
A perspective of the closed housing from the connector end, showing the molded shroud, the lead-receiving bore and its slotted aperture, and the section line for the later cross-section cuts. US patent drawing — public domain.Impact · why this shaft matters
The idea that closes this shaft is small and permanent: shape the interior so the parts seat themselves, bond them the way the chip industry bonds wire, then close the lid once — and make the closing perfect. Thirty years of the corpus are refinements of that single, irreversible act.