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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

Authentic archival layout formatted for framing, study, and high-resolution printing

Paper:
Theme:
The United States Patent & Trademark Archive

Historical Specification & Engineering Broadside

Curated, Verified & Restored by Classic Patents (classic-patents.com)
EXPLOSIVE-GAS MARINE ENGINEA friction-coupled, reversible screw-propeller installation for a gas or petroleum motor
US 361,931Class: B63H 23/30 (marine-propulsion power transmission characterized by clutches)
Inventor(s):Gottlieb Daimler
Origin / Location:Cannstatt, Würtemberg, Germany
Grant & Filing:Filed November 9, 1886 · Granted April 26, 1887

I. Historical Context & Grant Summary

Granted on April 26, 1887, US 361,931 describes Gottlieb Daimler's installation of a gas or petroleum motor in a boat or vessel. The specification couples an in-line motor shaft to a longitudinally movable propeller shaft, uses friction contact for forward motion and a reversing arrangement for backward motion, and also sets out steering, thrust-bearing starting, water cooling, and gas-reservoir arrangements. It is not a motor-carriage patent.

II. Core Mechanism & Scientific Principles

The patent addresses a marine installation, not a road vehicle. Daimler proposes replacing a vessel's steam engine, coal, water, and associated ballast with a gas or petroleum motor, then solving the installation problems that follow: engaging a screw propeller gradually, reversing it, taking propeller thrust, steering from the same station, cooling the cylinder, and storing combustible gas aboard.

Physical Operation:The motor shaft and propeller shaft are in line. For forward motion, the operator moves the propeller shaft toward the motor until two half-couplings make frictional contact; propeller thrust is intended to maintain that contact. For reverse, the shaft moves back, separating the forward coupling while levers press intermediate friction disks against a reversing disk. The patent therefore changes propeller direction through a mechanical coupling arrangement while the motor is described as running continuously in one direction.
Governing Formulation:
Frictional torque transmission:T \leq \mu N r
Propeller thrust as an axial load:F_T = \dot{m}(v_{\text{wake}} - v_{\text{inlet}})
Water-jacket heat removal:\dot Q = \dot m c_p (T_{\text{out}}-T_{\text{in}})

III. The Granted Legal Monopoly (Key Claims)

Claim 1 (Independent)In-line motor and propeller shafts

Claim 1 covers the specified vessel propulsion combination: an in-line gas or petroleum motor, a propeller shaft with one clutch member, an engine shaft with the other member for ahead motion, and gearing for astern motion.

Claim 2 (Independent)Longitudinally movable propeller shaft

Claim 2 covers an in-line gas or petroleum motor and a propeller shaft that slides longitudinally in its bearings. That axial movement engages or disengages the shaft's friction-clutch half with the matching half on the engine shaft, defining the claimed ahead-drive control relationship.

Claim 3 (Independent)Thrust-maintained coupling contact

Claim 3 requires the gas or petroleum motor, its friction-coupled propeller shaft, and bearings that allow longitudinal sliding. Its distinct legal result is that propeller thrust, once the coupling is engaged, maintains the frictional contact while the propeller is moving.

IV. Mechanical Organ Breakdown

Movable propeller shaft and forward couplingTerm: “half-coupling” → One mating member of a friction clutch

The propeller shaft slides longitudinally so its half-coupling can engage the half-coupling fixed to the motor shaft.

Reverse mechanismTerm: “friction-disks” → Friction clutch plates

Drawing the shaft back releases the ahead coupling and presses intermediate disks against a reversing disk.

Combined operating stationTerm: “screw-spindle” → Threaded control screw

The control hardware groups propulsion engagement and steering at the steersman's seat.

Thrust bearing and starting crankTerm: “thrust-bearing” → Axial-load bearing

A bearing at the motor's front takes propeller thrust and temporarily turns the motor for starting.

CLASSIC PATENTS DIGITAL ARCHIVE • PERMANENT EXHIBIT ID: us-361931-daimler-engine
classic-patents.com/patents/us-361931-daimler-engine
Original USPTO PDF
Classic Patents/US 361,931
Gilded Age & Grid (1870–1900)Marine Propulsion & Internal-Combustion Engines

Marine Propulsion Engine

US 361,931

A friction-coupled, reversible screw-propeller installation for a gas or petroleum motor

Inventor(s)Gottlieb Daimler
Grant DateApril 26, 1887
Filing DateNovember 9, 1886
LocationCannstatt, Würtemberg, Germany
Granted on April 26, 1887, US 361,931 describes Gottlieb Daimler's installation of a gas or petroleum motor in a boat or vessel. The specification couples an in-line motor shaft to a longitudinally movable propeller shaft, uses friction contact for forward motion and a reversing arrangement for backward motion, and also sets out steering, thrust-bearing starting, water cooling, and gas-reservoir arrangements. It is not a motor-carriage patent.
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 addresses a marine installation, not a road vehicle. Daimler proposes replacing a vessel's steam engine, coal, water, and associated ballast with a gas or petroleum motor, then solving the installation problems that follow: engaging a screw propeller gradually, reversing it, taking propeller thrust, steering from the same station, cooling the cylinder, and storing combustible gas aboard.
The Core Breakthrough Mechanism

The motor shaft and propeller shaft are in line. For forward motion, the operator moves the propeller shaft toward the motor until two half-couplings make frictional contact; propeller thrust is intended to maintain that contact. For reverse, the shaft moves back, separating the forward coupling while levers press intermediate friction disks against a reversing disk. The patent therefore changes propeller direction through a mechanical coupling arrangement while the motor is described as running continuously in one direction.

Interactive Real-Time Physical Simulation

Drag to rotate · Pinch to zoom · Shared controls update the displayed model
INITIALIZING THREE.JS WEBGL SIMULATION...
Marine Ahead/Astern Coupling and Cooling Arrangement.
Host-Model Telemetry/Computed Readout
Marine Ahead/Astern Coupling and Cooling Arrangement
Drive Selection
Reader Scenario
aheadreader control[1]
Ahead Contact
Source
coupling a / a²source labels[1]
Astern Contact
Source
opensource labels[1]
Cooling Circulation
Source
fore-and-aft pipes s¹ / s²source alternatives[1]
Sliding-Shaft Diagram Coordinate
∂q_{shaft} / ∂u_{selector} (host sensitivity)
1 normalized display coordinate / selector unit
Longitudinal Propeller-Shaft Position+1 astern / neutral / ahead
Centrifugal Cooling Pump u0 off / on
Interval ghosts
Drive1.0 astern / neutral / ahead · [-1, 1]

Detailed Component Architecture

1Movable propeller shaft and forward coupling
The propeller shaft slides longitudinally so its half-coupling can engage the half-coupling fixed to the motor shaft.

The source calls for a propeller shaft in line with the motor shaft and capable of longitudinal motion in its bearings. Pushing it forward produces frictional engagement for starting ahead; the propeller's thrust is said to maintain contact. The source permits either conical or flat coupling faces and specifies gradual engagement through spring and control hardware.

19th-C. Term: half-couplingModern: One mating member of a friction clutch
2Reverse mechanism
Drawing the shaft back releases the ahead coupling and presses intermediate disks against a reversing disk.

Elbow levers transmit the shaft's longitudinal movement to the intermediate disks. Their pressure makes the screw rotate in the contrary direction for astern propulsion. The specification also discloses an alternative with bevel wheels kept in mesh, but does not claim a vehicle differential.

19th-C. Term: friction-disksModern: Friction clutch plates
3Combined operating station
The control hardware groups propulsion engagement and steering at the steersman's seat.

A screw spindle, hand wheel or crank, lever, collars, and spring control forward motion of the propeller shaft. A rudder shaft is operated by levers, and the patent says the spindle may pass through or sit beside that steering shaft so the controls are together at seat p. This is a positional arrangement, not an automobile steering system.

19th-C. Term: screw-spindleModern: Threaded control screw
4Thrust bearing and starting crank
A bearing at the motor's front takes propeller thrust and temporarily turns the motor for starting.

The bearing contains a sliding pin that can engage a stud on the motor shaft. Turning its crank starts the engine; once started, the inclined pin is pushed out of gear so the bearing and crank remain stationary. The arrangement keeps propeller axial load and starting action in the described bearing assembly.

19th-C. Term: thrust-bearingModern: Axial-load bearing
5Cooling and gas storage
The specification uses surrounding water for cylinder cooling and describes vessel spaces as gas reservoirs.

Cooling water may be driven through a cylinder jacket by the vessel's forward motion through siphon-like piping, by a centrifugal pump, or by both. For combustible gas, high-pressure holders feed a low-pressure bag-like reservoir; the source says lined hull spaces and holders can also serve as floats. These are named arrangements and conditions of the marine installation, not claims about a gasoline road engine.

19th-C. Term: gas-holderModern: Pressurized gas storage vessel
Engineering Principles & Equations

Governing Equations & Engineering Principles

Authored explanation paired with its stated mathematical relation

Claim 3: Propeller Thrust Maintains Coupling Contact

Marine Propulsion MechanismClaim 3
Mathematical Governing Law
Terms:
Plain English DecoderHover or tap any highlighted phrase
With the sliding propeller shaft placed in ahead engagement, supplies the axial action that maintains . The patent states this mechanical relationship but gives no force, torque, speed, power, cone angle, or efficiency value.
FcontactF_{\text{contact}}
Coupling Contact Action
The frictional contact maintained between the engine and longitudinally sliding propeller-shaft coupling members in ahead motion.
source-stated qualitative relation

Claim 3 states that propeller thrust maintains the coupling's frictional contact; the grant does not quantify that contact force.

Physical Principle & Engineering Insight

This is a source-bounded force-path diagram, not a measured performance model. It supplies no later engine-specific speed, ignition timing, displacement, brake-power, clutch-material, or vessel-dimension claim that US 361,931 does not print.

Historical Context: The claimed installation couples an in-line gas or petroleum motor to a vessel propeller shaft and uses the propeller's own axial thrust to maintain ahead-drive frictional contact.

Frictional torque transmissionAuthored Principle 1
Stated relationT≤μNrT \leq \mu N r
The forward and reverse arrangements depend on normal force pressing friction surfaces together. Increasing that force raises the torque that can be transmitted before slip, subject to the friction coefficient μ and effective radius r. The source's spring, lever, and spindle provide the engagement force; it gives no numerical coefficient, force, or speed.
Propeller thrust as an axial loadAuthored Principle 2
Stated relationFT=m˙(vwake−vinlet)F_T = \dot{m}(v_{\text{wake}} - v_{\text{inlet}})
A propeller accelerates water and experiences an opposing axial thrust. The patent uses that thrust mechanically: in ahead motion it is stated to maintain the required coupling contact, while a thrust bearing receives the load. The formula is a modern momentum-accounting explanation, not a formula printed in the 1887 patent.
Water-jacket heat removalAuthored Principle 3
Stated relationQ˙=m˙cp(Tout−Tin)\dot Q = \dot m c_p (T_{\text{out}}-T_{\text{in}})
Water circulated through the cylinder jacket removes heat in proportion to its mass flow, heat capacity, and temperature rise. The facsimile proposes flow caused by forward motion, a centrifugal pump, or their combination; it does not state temperatures or flow rates.

Interactive Schematic Sheet (Figs. 1–6)

The three drawing sheets show a vessel with its motor, propeller, steering and cooling arrangements, the thrust-bearing details, and high-pressure gas-holder sections. All labels and views are from the US 361,931 facsimile.

1.00x
US 361,931 · FIGS. 1–6
Tap any numbered pin6 Curated Callouts
Callout Pin Inspector

Select Any Numbered Pin

Click pins on the schematic or select from the list below to inspect historical specifications.

Why It Still Matters

The record preserves a distinct 1887 marine-propulsion design problem: joining an internal-combustion motor to a screw propeller while providing controlled ahead and astern motion, steering, axial-load support, cooling, and onboard fuel-gas storage. Its ten claims make those combinations legible without converting the document into a patent for a motor carriage.

Legal Claims Decoder (10 Numbered Claims)

Compare dense legalistic claims directly with decoded plain-English functional specifications.
Claim #1Independent Master Claim
1/10
Verbatim Historical Legal Text
“The combination, with the propeller and propeller-shaft of a vessel and with part of a friction-coupling on said shaft, of a gas or petroleum motor-engine having its shaft arranged in line with the propeller-shaft and provided with part of a friction-coupling for effecting the forward motion of the vessel and gearing between the propeller-shaft and the part of the friction-coupling on the engine for effecting the backward motion of the vessel, substantially as described.”
Plain English Engineering Translation
Claim 1 covers the specified vessel propulsion combination: an in-line gas or petroleum motor, a propeller shaft with one clutch member, an engine shaft with the other member for ahead motion, and gearing for astern motion.
Key Protected Innovations:
In-line motor and propeller shaftsForward friction couplingAstern gearing
Historical Legal Impact:
This is a combination claim; its scope is limited to the stated vessel, shaft, coupling, and reverse-gearing arrangement.

The Historical Bottleneck

The specification identifies the marine burden it addresses: a steam engine requires coal, water, and metal ballast, increasing a vessel's immersion and consuming capacity that could carry a load.

Why Prior Art Failed

  • •The patent contrasts its gas or petroleum motor installation with a steam engine and its stated coal, water, and ballast burden.
  • •The source says the propeller installation needs controlled starting, stopping, reversing, steering, thrust support, cylinder cooling, and, when gas is used, onboard storage.
The Breakthrough Insight
“The source's central installation move is a longitudinally movable propeller shaft: friction contact carries the vessel ahead, a reversing disk arrangement carries it astern, and the controls can be located together at the steersman's seat.”
Civilizational Impact
US 361,931 documents an 1886–87 attempt to make a gas or petroleum motor serve a complete marine-propulsion system. Its claims preserve specific mechanical and cooling combinations for a vessel, rather than a generic story of road transport.
Historical Fact
The signed specification names Wilhelm Maybach and Herman Keppler as its two witnesses; the three drawing sheets instead bear the lithographic witnesses George B. Ailes and Robert Garrett.
Further Context
  • The specification records French, Belgian, Italian, German, and British patent activity, with the dates and numbers printed in its heading and opening paragraph.
  • It refers to Daimler's US Patent No. 349,983, dated September 28, 1886, for the gas or petroleum motor employed by preference.
Technological Lineage & Descent

The Evolution of Motive Power

From External Steam Condensation to Continuous Reaction Turbojets

A 170-year continuous mechanical lineage spanning external thermal condensation, precision cut-off steam engines, 4-stroke internal combustion, reaction steam turbines, and continuous jet propulsion.

1769Foundational Origin
GB 913

Watt Separate Condenser Steam Engine

Separate external steam condenser eliminating cylinder cyclic quenching.

1849Thermal Efficiency Leap
US 6,162

Governor-Controlled Slide-Valve Gear

Wrist-plate rotary valves with governor-controlled variable expansion cut-off.

1877Four-Stroke Cycle
US 194,047

Otto's Gradual-Combustion Gas Engine

Four-stroke compression-ignition Otto cycle internal combustion.

1887High-Speed Petroleum EngineThis Patent
US 361,931

Marine Propulsion Engine

Lightweight, high-speed single-cylinder gasoline engine with surface carburetor.

1895Compression Ignition
US 542,846

Diesel Controlled-Combustion Heat Motor

Extreme compression air heating triggering self-ignition of injected liquid fuel.

1898Reaction Steam Turbine
US 608,969

Parsons Selectable Marine Turbine Trains

Multi-stage axial reaction steam expansion across alternating fixed/moving blades.