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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:
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The United States Patent & Trademark Archive

Historical Specification & Engineering Broadside

Curated, Verified & Restored by Classic Patents (classic-patents.com)
IMPROVEMENT IN LOCKSShear-Line Pin Alignment, Flat Corrugated Keyway, Rotating Plug, and Modular Threaded Mortise Cylinder
US 48,475Class: 70/375
Inventor(s):Linus Yale, Jr.
Origin / Location:Shelburne Falls, Massachusetts
Grant & Filing:Granted June 27, 1865

I. Historical Context & Grant Summary

Linus Yale Jr.'s 1865 patent describes a lock combining a cylindrical tumbler-case, a rotating plug, two-piece pin tumblers, a thin bitted key, and a lost-motion wing or lazy-arm. The same specification also claims a spring plate for retaining the bolt and threaded cylinder mounting that can be adapted to either hand of lock and to doors of different thicknesses.

II. Core Mechanism & Scientific Principles

The specification addresses two practical problems in a tumbler lock: resistance to picking and the difficulty of adapting a lock to either hand of door and to different door thicknesses. Yale's design puts the key-operated tumblers in a cylindrical case that screws into the lock-case, while a thin wing or lazy-arm actuates and stops the bolt. The key raises the two-piece tumblers until their division lines are in line with the periphery of the plug. The document does not state a pin count, machining tolerance, key thickness, or universal door-thickness range; those values remain unspecified here.

Physical Operation:In the locked state, the springs press the two-piece tumblers across the boundary between the stationary tumbler-case and the rotating plug. Inserting the thin key raises the lower pieces so that every division between pieces is brought into line with the plug's periphery; the specification gives no numerical tolerance. The plug can then turn, and its ring recess and axial groove engage the lazy-arm's knob. The lazy-arm moves through less than the plug's whole revolution, so its wing remains in contact with a bolt talon at the locked and unlocked positions.
Governing Formulation:
Shear-Line Boundary Kinematics & Geometric Tolerances:y_{\mathrm{division},i} = y_{\mathrm{shear\ line}}\quad\text{for every tumbler }i
Hooke's Law Spring Restoration & Shear Binding Torque:F_i = k_i\,\Delta x_i
Lost-Motion Cam Kinematics & Mechanical Deadlocking:0 < \theta_{\mathrm{lazy\mbox{-}arm}} < 2\pi

III. The Granted Legal Monopoly (Key Claims)

Claim 1 (Independent)Front-insertable deadbolt mechanism

Claims the novel elastic spring-plate contrivance and clamping screw that holds the sliding deadbolt inside the mortise lock case, enabling the entire bolt assembly to be inserted or serviced directly through the front mortise faceplate after the lock case is mounted in the door.

Claim 2 (Independent)Reversible right/left hand lock orientation

Claims the combination of a mortise lock case and an interchangeable cylindrical tumbler housing, arranged so the cylinder can be mounted into either the right or left face of the case and adjusted to fit doors of any thickness.

Claim 3 (Independent)Threaded mortise cylinder housing

Claims an externally threaded tumbler cylinder screwed into a tapped nut in the lock case and clamped in place by an off-axis locking screw accessed through the front bolt opening.

IV. Mechanical Organ Breakdown

Revolving Plug & Eccentric Cylinder HousingTerm: “cylinder D eccentric to the tumbler-case” → Revolving Lock Core / Plug Cylinder

The inner cylindrical core that contains the keyway slot and pin chambers, mounted eccentrically inside the externally threaded tumbler-case.

Two-Piece Split Pin Tumblers & Compression SpringsTerm: “tumblers or pins made in two pieces, I and J” → Driver Pins & Key Pins (Pin Stack)

Pin chambers contain paired tumbler pieces I and J, with springs L pressing the pieces toward the plug.

Flat Serrated Bitted Key BladeTerm: “thin slip of steel properly shaped (key K)” → Flat Bitted Paracentric Key

A thin slip of steel shaped to bring the divisions between the tumbler pieces into one line.

Anti-Pick Circumferential Serrations & Racked ChambersTerm: “racked pin-tumblers and notched containing-recesses” → Serrated Security Pins / Spool Pins

Notches or screw-like cuts on the tumblers or their containing recesses, used with the narrow key-hole and comparatively large cavities.

CLASSIC PATENTS DIGITAL ARCHIVE • PERMANENT EXHIBIT ID: us-48475-yale-lock
classic-patents.com/patents/us-48475-yale-lock
Original USPTO PDF
Classic Patents/US 48,475
Industrial Revolution & Mechanical Age (1760–1870)Mechanical Locks & Security Systems

Yale Pin-Tumbler Cylinder Lock & Flat Bitted Key

US 48,475

Shear-Line Pin Alignment, Flat Corrugated Keyway, Rotating Plug, and Modular Threaded Mortise Cylinder

Inventor(s)Linus Yale, Jr.
Grant DateJune 27, 1865
Filing DateNot recorded
LocationShelburne Falls, Massachusetts
Linus Yale Jr.'s 1865 patent describes a lock combining a cylindrical tumbler-case, a rotating plug, two-piece pin tumblers, a thin bitted key, and a lost-motion wing or lazy-arm. The same specification also claims a spring plate for retaining the bolt and threaded cylinder mounting that can be adapted to either hand of lock and to doors of different thicknesses.
USPTO PDF
Audio Engineering Breakdown~2 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 specification addresses two practical problems in a tumbler lock: resistance to picking and the difficulty of adapting a lock to either hand of door and to different door thicknesses. Yale's design puts the key-operated tumblers in a cylindrical case that screws into the lock-case, while a thin wing or lazy-arm actuates and stops the bolt. The key raises the two-piece tumblers until their division lines are in line with the periphery of the plug. The document does not state a pin count, machining tolerance, key thickness, or universal door-thickness range; those values remain unspecified here.
The Core Breakthrough Mechanism

In the locked state, the springs press the two-piece tumblers across the boundary between the stationary tumbler-case and the rotating plug. Inserting the thin key raises the lower pieces so that every division between pieces is brought into line with the plug's periphery; the specification gives no numerical tolerance. The plug can then turn, and its ring recess and axial groove engage the lazy-arm's knob. The lazy-arm moves through less than the plug's whole revolution, so its wing remains in contact with a bolt talon at the locked and unlocked positions.

Interactive Real-Time Physical Simulation

Drag to rotate · Pinch to zoom · Shared controls update the displayed model
INITIALIZING THREE.JS WEBGL SIMULATION...
Mechanical Shear-Line Kinematics & Pin-Tumbler Dynamics.
Host-Model Telemetry/Computed Readout
Mechanical Shear-Line Kinematics & Pin-Tumbler Dynamics
Shear Line Alignment
Normalized
Aligned (Shear Cleared)Status[1]
Max Pin Shear Error
Modern Model
0.000 mmΔy_max[1]
Plug Rotation Angle
Normalized
2.5°θ_plug[1]
Bolt Extension / Deadlock
Modern Model
0.5 mm x_bolt[1]
Pin Spring Force
Modern Model
2.93 NF_spring[1]
Theoretical Combinations
Modern Model
7,776 (6⁵)perms[1]
Pin Tumbler Shear Line Alignment
∂Alignment / ∂x_key (host sensitivity)
1 unit / unit
Key Blade Insertion Depth1 fraction
Turning Torque on Plug0.15 N·m
Interval ghosts
Pins5.0 pins · [3, 7]
Fidelity / MMS residual
Key bitting shear line clearance vs 1865 master
model0.05 mm
reference0.05 mm
residual0.00 mm
Coupled channels
key force → shear line lift1 W
Dated scenarios

Detailed Component Architecture

1Revolving Plug & Eccentric Cylinder Housing
The inner cylindrical core that contains the keyway slot and pin chambers, mounted eccentrically inside the externally threaded tumbler-case.

Plug D revolves in the cylindrical bore of tumbler-case C. The case has an external thread that engages a tapped hole in either side of lock-case A, and a jam-nut or pointed screw H can hold the case at the desired depth so its end remains flush with the door. The source gives no material, diameter, or door-thickness dimensions.

19th-C. Term: cylinder D eccentric to the tumbler-caseModern: Revolving Lock Core / Plug Cylinder
2Two-Piece Split Pin Tumblers & Compression Springs
Pin chambers contain paired tumbler pieces I and J, with springs L pressing the pieces toward the plug.

The source says only that pieces I and J have different lengths and that each tumbler is provided with a spring. The key is shaped so the divisions between the pieces lie in one line before plug D can turn. No pin dimensions, spring constant, material, or force value is stated.

19th-C. Term: tumblers or pins made in two pieces, I and JModern: Driver Pins & Key Pins (Pin Stack)
3Flat Serrated Bitted Key Blade
A thin slip of steel shaped to bring the divisions between the tumbler pieces into one line.

The specification calls K a thin slip of steel and describes its shape in relation to the pin divisions and narrow key-hole. It does not quantify the blade thickness, number of bittings, key-space size, or weight reduction.

19th-C. Term: thin slip of steel properly shaped (key K)Modern: Flat Bitted Paracentric Key
4Anti-Pick Circumferential Serrations & Racked Chambers
Notches or screw-like cuts on the tumblers or their containing recesses, used with the narrow key-hole and comparatively large cavities.

Yale says these notches serve the purpose of racking on vibrating or rotating tumblers and prevent picking to a certain extent. The narrow key-hole leaves most of each containing cavity supporting the part that projects into the key-hole, reducing the risk of jamming under key thrust. The source does not quantify a picking force or friction coefficient.

19th-C. Term: racked pin-tumblers and notched containing-recessesModern: Serrated Security Pins / Spool Pins
5Lost-Motion Cam (Lazy-Arm) & Deadbolt Deadlock
A thin wing that engages the plug's groove, actuates the bolt talons, holds the cylinder in place, and stops the plug at the key-removal positions.

Wing E is formed from thin steel with knob v engaging groove t. The source says the key-hole cylinder can turn nearly a whole revolution without moving the wing, while the wing moves less than a whole revolution and remains in contact with a bolt talon at both locked and unlocked positions. It does not state an angular value or a zero-torque condition.

19th-C. Term: wing or lazy-arm EModern: Lost-Motion Drive Cam & Deadbolt Actuator
Engineering Principles & Equations

Governing Equations & Engineering Principles

Authored explanation paired with its stated mathematical relation

Pin-Tumbler Shear-Line Boundary Condition & Alignment Kinematics

Precision Mechanics & Cryptographic LocksClaim 4
Mathematical Governing Law
Terms:
Plain English DecoderHover or tap any highlighted phrase
The equals the absolute difference between the plus and the , which must remain within the for the cylinder to rotate.
Δyi\Delta y_i
Pin Shear Line Alignment Error
Distance between the pin parting line and the outer cylinder shear boundary (<0.09 mm< 0.09\text{ mm})
Millimeters (mm)

If any single pin has an error exceeding tolerance, it physically spans the shear line and mechanically blocks rotation.

Physical Principle & Engineering Insight

Linus Yale Jr.'s pin-tumbler cylinder lock separates the keyway and pin stack from the bolt-throwing mechanism. Only when all five split-pin division lines simultaneously align flush with the revolving plug circumference can the cylinder rotate.

Historical Context: US 48,475 established the modern pin-tumbler cylinder lock and small flat bitted key, making heavy, bulky Victorian bit keys obsolete and becoming the universal security standard worldwide.

Hooke's Law Spring Dynamics & Shear Binding Torque

Solid Mechanics & Friction DynamicsClaim 4
Mathematical Governing Law
Terms:
Plain English DecoderHover or tap any highlighted phrase
The depends on the and , while equals minus whenever pins cross the shear boundary.
FsF_s
Total Spring Restorative Force
Sum of downward forces exerted by all 5 pin compression springs (2.5 to 5.0 N2.5\text{ to }5.0\text{ N})
Newtons (N)

Continuously pushes driver pins across the shear line when the key is withdrawn.

Physical Principle & Engineering Insight

Yale's introduction of circumferential notches (spools and serrations) on the pins creates false-set gates: when a lockpicker applies turning torque, the serration catches in the housing groove, generating counter-rotation feedback and deadlocking the plug.

Historical Context: The Yale lock combined high spring reliability, anti-pick serrations, and extreme physical compactness in a single mass-manufacturable brass cylinder.

Shear-Line Boundary Kinematics & Geometric TolerancesAuthored Principle 1
Stated relationydivision,i=yshear linefor every tumbler iy_{\mathrm{division},i} = y_{\mathrm{shear\ line}}\quad\text{for every tumbler }i
The plug can turn only when the division between each pair of tumbler pieces is brought into the same line at the plug's periphery. The patent states the alignment condition but supplies no numerical machining tolerance.
Hooke's Law Spring Restoration & Shear Binding TorqueAuthored Principle 2
Stated relationFi=ki ΔxiF_i = k_i\,\Delta x_i
The springs provide the restoring action that pushes the tumbler pieces toward their recesses. Their stiffness and travel are not specified in the patent, so the general spring relation is the most that can be stated quantitatively here.
Lost-Motion Cam Kinematics & Mechanical DeadlockingAuthored Principle 3
Stated relationMathematical notation unavailable
The key-hole cylinder must reach a key-removal position, but Yale's lazy-arm is arranged to move through less than a whole revolution and remain against a bolt talon at both terminal positions. This is the claimed lost-motion relationship, not a quantified torque guarantee.

Interactive Schematic Sheet (Fig. 1)

Side elevation of the mortise lock case showing the circular threaded aperture and mounted cylinder.

1.00x
US 48,475 · FIG. 1
Tap any numbered pin3 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 patent is an early primary description of a pin-tumbler cylinder with a thin bitted key, threaded case mounting, bolt-retaining plate, and lost-motion lazy-arm. Later lockmaking may be compared with these mechanisms, but this record does not assign a percentage of modern locks or claim a particular industrial lineage without separate evidence.

Legal Claims Decoder (5 Numbered Claims)

Compare dense legalistic claims directly with decoded plain-English functional specifications.
Claim #1Independent Master Claim
1/5
Verbatim Historical Legal Text
“1. The contrivance, substantially as described, for holding a bolt in place.”
Plain English Engineering Translation
Claims the novel elastic spring-plate contrivance and clamping screw that holds the sliding deadbolt inside the mortise lock case, enabling the entire bolt assembly to be inserted or serviced directly through the front mortise faceplate after the lock case is mounted in the door.
Key Protected Innovations:
Front-insertable deadbolt mechanismElastic spring retention plateThrough-faceplate servicing and installation

The Historical Bottleneck

The specification addresses a mid-19th-century lockmaking problem: retain the bolt in a mortise case, adapt a cylinder to either hand of door and to different door thicknesses, and make a pin-lock less susceptible to picking.

Why Prior Art Failed

  • •A bolt could need to be inserted through the lock's bolt-hole after the case was already fitted to the door.
  • •A cylinder fixed at one depth or on one side of a case would not adapt readily to different doors or handing.
  • •The specification identifies picking and unsupported tumbler ends as practical failure modes for the pin-lock arrangement it improves.
The Breakthrough Insight
“Linus Yale Jr. separated the key cylinder from the bolt throw mechanism, using spring-loaded two-piece tumblers aligned at the plug periphery by a small, thin bitted key.”
Civilizational Impact
The document preserves a compact combination of pin alignment, threaded cylinder mounting, bolt retention, and lost-motion bolt control. Its later influence on lock hardware requires separate historical evidence and is not quantified here.