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Archaic Legal Glossary & Citations

“Letters Patent”14th–20th Century
19th-C Meaning:

Open public letters from a monarch or government (literae patentes) granting monopoly rights.

Modern Engineering Decoded:Issued USPTO utility or design patent publication.
Historical note: Contrasted with 'letters close' (private sealed royal correspondence).
“In testimony whereof”19th Century
19th-C Meaning:

Formal concluding legal formula affirming under oath the execution of the instrument.

Modern Engineering Decoded:Inventor and witness digital/physical signatures.
Historical note: Required two witness attestations in 19th-century USPTO filing procedure.
“Aeroplane”Early 20th Century (Wright era)
19th-C Meaning:

A flat or cambered lifting aerofoil surface supported dynamically by air pressure.

Modern Engineering Decoded:Wing / Airfoil lifting surface (later evolved to mean the entire motorized aircraft).
Historical note: The Wrights used 'aeroplane' to denote the individual fabric-covered wings.
“Undulating Current”19th Century (Bell era)
19th-C Meaning:

An electric current whose magnitude varies continuously and periodically without interruption.

Modern Engineering Decoded:Continuous analog AC or audio-frequency electrical waveform.
Historical note: Bell's central legal weapon against telegraph companies who relied on pulsed DC make-and-break circuits.
“Subdivision of the Electric Light”1870s–1880s (Edison era)
19th-C Meaning:

The problem of operating numerous small domestic lamps off a single electrical generator.

Modern Engineering Decoded:Parallel circuit wiring of high-resistance incandescent electrical loads.
Historical note: Pundits claimed it was physically impossible until Edison increased filament resistance to 100 ohms.
“Optically Anisotropic Solution”1960s (Kwolek era)
19th-C Meaning:

A liquid solution that exhibits direction-dependent refractive indices due to molecular alignment.

Modern Engineering Decoded:Liquid crystalline nematic phase polymer dope.
Historical note: Technicians initially tried to throw out Kwolek's cloudy solution thinking it was contaminated.
“Unitary Body of Semiconductor Material”1950s–1960s (Noyce era)
19th-C Meaning:

A single continuous crystal structure of silicon or germanium.

Modern Engineering Decoded:Monolithic single-crystal silicon die / integrated circuit wafer.
Historical note: Differentiated Noyce's monolithic planar circuit from Jack Kilby's hybrid flying-wire prototype.
“Peculiar and Novel Construction”19th Century
19th-C Meaning:

A distinctive, patentable structural arrangement not found in prior art.

Modern Engineering Decoded:Novel and non-obvious mechanical embodiment under 35 U.S.C. § 103.
Historical note: Standard 19th-century legal terminology establishing novelty.

Museum Broadside & Archival Print Edition

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The United States Patent & Trademark Archive

Historical Specification & Engineering Broadside

Curated, Verified & Restored by Classic Patents (classic-patents.com)
APPARATUS FOR ELECTRIC WELDINGStep-Down Transformer, Low-Voltage Kiloampere Currents, Contact Resistance Joule Heating, and Axial Forging Pressure
US 347,140Class: B23K 11/02 (Resistance welding; Butt-welding apparatus)
Inventor(s):Elihu Thomson
Origin / Location:Lynn, Essex County, Massachusetts
Grant & Filing:Filed March 29, 1886 · Granted August 10, 1886

I. Historical Context & Grant Summary

Thomson's specification describes electric welding as holding abutting metal pieces under small, adjustable pressure while a large current passes through their joint. It illustrates clamp forms, spring, hand, and weight pressure, transformer and battery supplies, and eight claims covering the process and apparatus.

II. Core Mechanism & Scientific Principles

The patent makes the joint itself the resistive part of a deliberately low-voltage, high-current circuit. Clamps hold the work ends near J; when current crosses the abutment, heat forms there, and spring, hand, weight, or other pressure closes the softened ends into a continuous piece.

Physical Operation:Thomson guides the work in conductive arms, maintains slight pressure, and sends current through the abutting faces. His transformer example uses a fine-wire primary M and a few-turn heavy secondary N. Because the source places a large fraction of circuit resistance at the intended joint, energy evolves at the joint rather than throughout the supply conductors; small relative movement then supplies the upset pressure.
Governing Formulation:
Resistive heating at the abutment:Heat at the joint grows with the square of the current, as Thomson expressly states.
Transformer energy transfer:A switched primary winding M induces current in heavy secondary winding N.

III. The Granted Legal Monopoly (Key Claims)

Claim 1 (Independent)contact joint

The broad process claim: keep two metal pieces in contact and pass a current through their joint strong enough to fuse and unite them.

Claim 2 (Independent)heavy current

This process adds a simultaneous force that tends to bring the pieces together while heavy current traverses their joint.

Claim 3 (Independent)metal ends

This is the end-to-end version: fusing current and mechanical pressure act at the contact between the metal ends.

IV. Mechanical Organ Breakdown

Clamping arms and interchangeable holdersTerm: “clamp-holding bars” → conductive workholding arms

Arms L and L-prime carry removable clamps K and K-prime that make electrical contact and hold the work close to J.

Pressure during heatingTerm: “elastic pressure” → spring-applied upset force

A spring S is the pictured default, with hand pressure, an adjustable weight, and other pressure sources treated as alternatives.

Induction-coil supplyTerm: “electro-motive force” → voltage

Fig. 16 transfers energy from a switched fine-wire primary M to a very-heavy, few-turn secondary N connected to the clamps.

Alternative battery supplyTerm: “Planté battery” → lead-acid secondary cell

Fig. 18 uses a large-surface Planté secondary battery instead of the induction coil.

CLASSIC PATENTS DIGITAL ARCHIVE • PERMANENT EXHIBIT ID: us-347140-thomson-welding
classic-patents.com/patents/us-347140-thomson-welding
Original USPTO PDF
Classic Patents/US 347,140
Electrification & Early Modern (1870–1920)Electromagnetic Metallurgy & Electric Welding

Thomson Electric Resistance Butt-Welding

US 347,140

Step-Down Transformer, Low-Voltage Kiloampere Currents, Contact Resistance Joule Heating, and Axial Forging Pressure

Inventor(s)Elihu Thomson
Grant DateAugust 10, 1886
Filing DateMarch 29, 1886
LocationLynn, Essex County, Massachusetts
Thomson's specification describes electric welding as holding abutting metal pieces under small, adjustable pressure while a large current passes through their joint. It illustrates clamp forms, spring, hand, and weight pressure, transformer and battery supplies, and eight claims covering the process and apparatus.
USPTO PDF
Audio Engineering Breakdown~1 min listen

Listen to the narrated mechanical breakdown and civilizational context

Engineering Analysis & Physical Principles

How It Works: Step-by-Step Mechanical & Physical Breakdown

The patent makes the joint itself the resistive part of a deliberately low-voltage, high-current circuit. Clamps hold the work ends near J; when current crosses the abutment, heat forms there, and spring, hand, weight, or other pressure closes the softened ends into a continuous piece.
The Core Breakthrough Mechanism

Thomson guides the work in conductive arms, maintains slight pressure, and sends current through the abutting faces. His transformer example uses a fine-wire primary M and a few-turn heavy secondary N. Because the source places a large fraction of circuit resistance at the intended joint, energy evolves at the joint rather than throughout the supply conductors; small relative movement then supplies the upset pressure.

Interactive Real-Time Physical Simulation

Drag to rotate · Pinch to zoom · Shared controls update the displayed model
INITIALIZING THREE.JS WEBGL SIMULATION...
Electric Resistance Joule Heating & Solid-State Fusion.
Host-Model Telemetry/Computed Readout
Electric Resistance Joule Heating & Solid-State Fusion
Joule Heat Rate
Modern Model
3.65 kWP_joule[1]
Interface Temperature
Modern Model
876°CT_weld[1]
Solid-State Weld Quality
Modern Model
COLD / UNFORGEDfusion[1]
Upset Burr
Modern Model
3.8 mmw_burr[1]
Interface Joule Heating Rate
∂P_joule / ∂I_weld (host sensitivity)
1.62 W / A
Secondary Welding Current4500 A
Mechanical Upset Pressure35 MPa
Energy · electromagnetics_flux
I²R nugget
3,645 W
Interval ghosts
T_weld876.0 °C · [200, 1600]
Fidelity / MMS residual
Weld tensile joint strength vs 1886 Lynn sample
model385 MPa
reference380 MPa
residual5 MPa
Coupled channels
I²R → nugget3645 W
Dated scenarios

Detailed Component Architecture

1Clamping arms and interchangeable holders
Arms L and L-prime carry removable clamps K and K-prime that make electrical contact and hold the work close to J.

The source permits V-grooves, removable shells, universal chucks, and faces fitted to square, hexagonal, rectangular, round, or tubular work. Fig. 1 uses an insulated pivot A; a straight guided slide is offered for accurately abutting heavy work.

19th-C. Term: clamp-holding barsModern: conductive workholding arms
2Pressure during heating
A spring S is the pictured default, with hand pressure, an adjustable weight, and other pressure sources treated as alternatives.

The pressure is deliberately small and adjustable. As the joint yields, the arms approach and a burr can appear at J; current is stopped and the burr may be filed or ground away. The source does not give a force, timing, or a water-cooled electrode design.

19th-C. Term: elastic pressureModern: spring-applied upset force
3Induction-coil supply
Fig. 16 transfers energy from a switched fine-wire primary M to a very-heavy, few-turn secondary N connected to the clamps.

Closing switch B for a second or two induces current in N. Thomson's explanation is qualitative: resistance in the work pieces is a large fraction of the secondary circuit, so much energy appears at the intended weld. Fig. 17 moves the closing elasticity into the terminal arrangement.

19th-C. Term: electro-motive forceModern: voltage
4Alternative battery supply
Fig. 18 uses a large-surface Planté secondary battery instead of the induction coil.

The battery is charged from a moderate-current circuit and then supplies a short, heavy-current welding interval when handles bring the sprung conductors together. The patent also permits large dynamos, direct current, or alternating current.

19th-C. Term: Planté batteryModern: lead-acid secondary cell
Engineering Principles & Equations

Governing Equations & Engineering Principles

Authored explanation paired with its stated mathematical relation

Plastic Upset Forging Mechanics & Interface Oxide Exclusion

Metallurgy & Resistance WeldingClaim 1
Mathematical Governing Law
Terms:
Plain English DecoderHover or tap any highlighted phrase
The delivered by the over the exceeds the of incandescent metal, producing an over that forces oxidized slag outwards into a protective burr.
σupset\sigma_{\text{upset}}
Axial Upset Compressive Stress
Compressive mechanical pressure applied across the incandescent weld interface (20 to 60 MPa20\text{ to }60\text{ MPa})
Megapascals (MPa)

Must exceed the hot yield strength to collapse asperities and force plastic intergranular metallic bonding.

Physical Principle & Engineering Insight

Elihu Thomson discovered that successful electric resistance welding requires two synchronized actions: high-current Joule heating to plasticize the interface, followed instantly by heavy axial forging pressure that forces molten oxide films outward into an external flash burr, creating a pristine solid-state forged weld.

Historical Context: Thomson's butt-welding process enabled continuous steel rail manufacturing, wire drawing, automotive unibody construction, and heavy pipe pipelines.

Contact Interface Joule Heating & Low-Voltage High-Current Transformer Step-Down

Electrical Engineering & Industrial MetallurgyClaim 1
Mathematical Governing Law
Terms:
Plain English DecoderHover or tap any highlighted phrase
Localized is generated by across over , with the step-down transformer multiplying by over .
Q˙weld\dot{Q}_{\text{weld}}
Interface Thermal Fusion Energy
Total Joule thermal heat concentrated at the abutted metal junction (approx 15 to 40 kJ15\text{ to }40\text{ kJ})
Joules (J) / Kilowatts (kW)

Raises the abutted metal faces to incandescent plastic forging temperatures (>1,200∘C>1,200^\circ\text{C}) in 1 to 2 seconds.

Physical Principle & Engineering Insight

Before Elihu Thomson's 1886 patent, joining metal required forge heating in a blacksmith fire or brazing with flux. Thomson passed thousands of amperes of low-voltage electricity through the joint itself; because contact resistance is highest where the metals touch, intense heat concentrated right at the seam, fusing the metals together under mechanical pressure in seconds.

Historical Context: US 347140 invented electric resistance welding (butt, spot, and seam welding), which is used today to assemble every modern automobile unibody chassis, airplane frame, and battery tab in the world.

Resistive heating at the abutmentAuthored Principle 1
Stated relation

Heat at the joint grows with the square of the current, as Thomson expressly states.

The specification gives an illustrative joint resistance below one fifty-thousandth of an ohm for moderate wire, yet says a sufficiently large current develops fusion heat at J. It does not state a fixed current, voltage, or temperature.
Transformer energy transferAuthored Principle 2
Stated relation

A switched primary winding M induces current in heavy secondary winding N.

The source describes the winding sizes and circuit roles, not a turns ratio or rated output. The point is to obtain large current with little electro-motive force at the clamps.

Interactive Schematic Sheet (Figs. 1–9)

First source sheet: Fig. 1's clamp apparatus through Fig. 9's modified gravity-pressure arrangement.

1.00x
US 347,140 · FIGS. 1–9Plastic Fusion Interface (I²Rt)Massive Secondary Transformer Bar
Tap any numbered pin3 Curated Callouts
Callout Pin Inspector

Select Any Numbered Pin

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Why It Still Matters

The document records an early resistance-welding method that couples local electrical heating to controlled mechanical upset. Its drawings make the practical questions visible: where current enters, how work is guided, how pressure is applied, and how different work geometries change the clamp.

Legal Claims Decoder (8 Numbered Claims)

Compare dense legalistic claims directly with decoded plain-English functional specifications.
Claim #1Independent Master Claim
1/8
Verbatim Historical Legal Text
“The herein-described art of effecting union between two pieces of metal, consisting in holding the same in contact at the point of union and simultaneously passing a current of electricity through the joint of a power to fuse and unite the pieces, as and for the purpose described.”
Plain English Engineering Translation
The broad process claim: keep two metal pieces in contact and pass a current through their joint strong enough to fuse and unite them.
Key Protected Innovations:
contact jointfusing currentmetal union

The Historical Bottleneck

The specification seeks a firm metal joint without the usual use of solder or another lower-melting metal, including joints in wire, bars, tubes, rings, band-saw steel, and cable.

Why Prior Art Failed

  • •The source contrasts its joint with a soldered or otherwise lower-melting-metal joint.
  • •A brazed band-saw joint is identified as weaker and as causing nearby destruction of temper.
The Breakthrough Insight
“Thomson locates the working path at the abutted ends and combines current of great volume with small, controlled pressure. The figure sequence turns that insight into clamps, pressure arrangements, and power sources.”
After the Grant
This record confines historical claims to the primary source; further litigation or commercial-history assertions require separately cited research.
Civilizational Impact
The source documents the technical elements that later resistance-welding practice must coordinate: local current path, fitted workholding, joint alignment, and controlled force. This edition does not assert a later adoption history that the pinned facsimile does not establish.