Skip to content

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)
MANIPULATORConcentric drive shafts, oblique roll axes, and a common orientation point
US 4,068,536Class: Int. Cl. F16H 1/14; U.S. Cl. 74/417 (printed)
Inventor(s):Theodore Hahn Stackhouse
Origin / Location:Cincinnati, Ohio
Grant & Filing:Filed December 23, 1976 · Granted January 17, 1978

I. Historical Context & Grant Summary

Stackhouse's grant describes a remotely operable robot wrist built from serial drive shafts, including two independently rotatable concentric-shaft sets on oblique axes and a third shaft. In the preferred arrangement the three axes intersect at one point, allowing the terminal axis to sweep a continuous spherical sector while hydraulic motors remain back at the elbow.

II. Core Mechanism & Scientific Principles

The patent addresses wrist orientation at the end of an industrial robot arm. Rather than putting a separate drive package at each distal joint, the preferred embodiment places three hydraulic motors at the elbow and transmits their rotations through three concentric forearm shafts, bevel gears, a second oblique shaft set, and a terminal shaft carrying the end effector.

Physical Operation:Outer forearm shaft 15 turns the split wrist housing about axis A–A′. Intermediate forearm shaft 16 drives bevel gears 17 and 18 to rotate housing shaft 14a about oblique axis B–B′. Inner forearm shafts 19/20 drive bevel gears 21/22, shaft 23, and bevel gears 24/25 to rotate terminal shaft 26 about axis C–C′. In the illustrated arrangement A–A′, B–B′, and C–C′ meet at point P. The grant states that both fixed oblique angles are greater than 45 degrees, so the generated spherical sector is greater than a hemisphere; it does not print exact angles, link dimensions, gear ratios, loads, speeds, or efficiencies.
Governing Formulation:
Serial rotation composition:\mathbf{R}_{tool}=\mathbf{R}_{A}(q_A)\,\mathbf{R}_{B}(q_B)\,\mathbf{R}_{C}(q_C)
Intersecting-axis spherical geometry:A\! -\! A',\;B\! -\! B',\;C\! -\! C'\rightarrow P
Ideal power continuity:\boldsymbol{\tau}_{in}^{T}\dot{\mathbf{q}}_{in}=\boldsymbol{\tau}_{out}^{T}\boldsymbol{\omega}_{out}+P_{loss}

IV. Mechanical Organ Breakdown

Three concentric forearm shaftsTerm: “intermost forearm shaft” → innermost coaxial drive shaft

Shafts 15, 16, and 19 rotate independently about the forearm axis and carry three motor inputs into the wrist.

First oblique transmissionTerm: “drivingly engaged” → meshed torque-transmitting connection

Bevel gears 17 and 18 convert rotation about forearm axis A–A′ into rotation about oblique axis B–B′.

Second oblique transmission and tool shaftTerm: “” →

Shaft 23 and bevel gears 24/25 carry the innermost input to terminal shaft 26 about axis C–C′.

Common intersection pointTerm: “” →

The preferred A–A′, B–B′, and C–C′ axes pass through point P, making the terminal direction a spherical-orientation problem.

CLASSIC PATENTS DIGITAL ARCHIVE • PERMANENT EXHIBIT ID: us-4068536-stackhouse-manipulator
classic-patents.com/patents/us-4068536-stackhouse-manipulator
Original USPTO PDF
Classic Patents/US 4,068,536
Information Age & Silicon Revolution (1960–1990)Industrial Robotics & Manipulator Kinematics

Stackhouse Intersecting-Axis Robot Wrist

US 4,068,536

Concentric drive shafts, oblique roll axes, and a common orientation point

Inventor(s)Theodore Hahn Stackhouse
Grant DateJanuary 17, 1978
Filing DateDecember 23, 1976
LocationCincinnati, Ohio
Stackhouse's grant describes a remotely operable robot wrist built from serial drive shafts, including two independently rotatable concentric-shaft sets on oblique axes and a third shaft. In the preferred arrangement the three axes intersect at one point, allowing the terminal axis to sweep a continuous spherical sector while hydraulic motors remain back at the elbow.
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 patent addresses wrist orientation at the end of an industrial robot arm. Rather than putting a separate drive package at each distal joint, the preferred embodiment places three hydraulic motors at the elbow and transmits their rotations through three concentric forearm shafts, bevel gears, a second oblique shaft set, and a terminal shaft carrying the end effector.
The Core Breakthrough Mechanism

Outer forearm shaft 15 turns the split wrist housing about axis A–A′. Intermediate forearm shaft 16 drives bevel gears 17 and 18 to rotate housing shaft 14a about oblique axis B–B′. Inner forearm shafts 19/20 drive bevel gears 21/22, shaft 23, and bevel gears 24/25 to rotate terminal shaft 26 about axis C–C′. In the illustrated arrangement A–A′, B–B′, and C–C′ meet at point P. The grant states that both fixed oblique angles are greater than 45 degrees, so the generated spherical sector is greater than a hemisphere; it does not print exact angles, link dimensions, gear ratios, loads, speeds, or efficiencies.

Interactive Real-Time Physical Simulation

Drag to rotate · Pinch to zoom · Shared controls update the displayed model
INITIALIZING THREE.JS WEBGL SIMULATION...
Intersecting-Axis Wrist Topology & Concentric Shaft Transmission.
Host-Model Telemetry/Computed Readout
Intersecting-Axis Wrist Topology & Concentric Shaft Transmission
Selected Display Bend
57.6° display[1]
Selected Display Azimuth
-67.4° display[1]
Axis Intersection
POINT Psource topology[1]
Printed Oblique Condition
>45° / >45°source inequality[1]
Orientation-Hole State
PREFERREDqualitative[1]
SI Dynamics / Performance
REFUSEDmissing source inputs[1]
Forearm Roll (θ₁)0 °
Intermediate Oblique Roll (θ₂)+72 °
Tool Spin Roll (θ₃)0 °
Selected A–B Obliquity55 ° display
Selected B–C Obliquity55 ° display
Preferred Common Point P1 offset/exact

Detailed Component Architecture

1Three concentric forearm shafts
Shafts 15, 16, and 19 rotate independently about the forearm axis and carry three motor inputs into the wrist.

Figure 4 places hydraulic motors 9a, 9b, and 9c at the elbow and connects them through spur gears to shafts 15, 16, and 19. The source specifies topology but no reusable torque, speed, inertia, or power values.

19th-C. Term: intermost forearm shaftModern: innermost coaxial drive shaft
2First oblique transmission
Bevel gears 17 and 18 convert rotation about forearm axis A–A′ into rotation about oblique axis B–B′.

Housing portion 14a is both a housing and a rotatable shaft. It is supported about B–B′ while the complete housing also moves with outer shaft 15 about A–A′, producing the source-described planetary motion.

19th-C. Term: drivingly engagedModern: meshed torque-transmitting connection
3Second oblique transmission and tool shaft
Shaft 23 and bevel gears 24/25 carry the innermost input to terminal shaft 26 about axis C–C′.

The terminal mounting surface 14c and end effector 11 turn with shaft 26. Because shaft 23 sits inside the rotating housing, its axis and the terminal axis move with the upstream wrist members instead of floating independently.

4Common intersection point
The preferred A–A′, B–B′, and C–C′ axes pass through point P, making the terminal direction a spherical-orientation problem.

The specification explicitly allows small deviations from exact coincidence, while warning that they create small orientation ‘holes.’ The exhibit therefore includes an exact-intersection/source-contrast control but does not claim singularity-free motion or a constant Jacobian determinant.

Engineering Principles & Equations

Governing Equations & Engineering Principles

Authored explanation paired with its stated mathematical relation

Selected Intersecting-Axis Display Composition

Source-Bounded Mechanism Geometry
Mathematical Governing Law
Terms:
Plain English DecoderHover or tap any highlighted phrase
The modern teaching composes the selected rolls about source axes , , and with two selected oblique angles satisfying the printed .
Rdisplay\mathbf{R}_{display}
Selected Display Orientation
Drawing-space orientation shared by the connected 2D and 3D exhibits
Dimensionless display

This is a modern serial-rotation teaching construction, not a motor calibration or equation printed in the grant.

Physical Principle & Engineering Insight

The composition makes the serial topology legible while refusing undisclosed dimensions, gear ratios, hydraulic dynamics, loads, power, precision, Jacobian, and singularity performance. Exact intersection at P is the preferred embodiment; the source also allows small deviations and warns that they create small orientation holes.

Historical Context: The grant documents a compact remotely driven industrial-robot wrist built from nested shafts, bevel gears, a preferred common orientation point.

Serial rotation compositionAuthored Principle 1
Stated relationRtool=RA(qA) RB(qB) RC(qC)\mathbf{R}_{tool}=\mathbf{R}_{A}(q_A)\,\mathbf{R}_{B}(q_B)\,\mathbf{R}_{C}(q_C)
Successive shaft rotations compose in order because each downstream axis moves with the upstream housing. This is a modern kinematic teaching notation, not an equation printed in the grant.
Intersecting-axis spherical geometryAuthored Principle 2
Stated relationA ⁣− ⁣A′,  B ⁣− ⁣B′,  C ⁣− ⁣C′→PA\! -\! A',\;B\! -\! B',\;C\! -\! C'\rightarrow P
When the three axes intersect at P, changing tool orientation does not require moving that geometric wrist center. The patent describes a spherical sector and says the illustrated fixed angles produce more than hemispherical directional coverage.
Ideal power continuityAuthored Principle 3
Stated relationτinTq˙in=τoutTωout+Ploss\boldsymbol{\tau}_{in}^{T}\dot{\mathbf{q}}_{in}=\boldsymbol{\tau}_{out}^{T}\boldsymbol{\omega}_{out}+P_{loss}
A real bevel-gear and bearing train must conserve input power apart from losses. Because the source supplies no torques, rates, ratios, or efficiencies, the public model refuses numerical power telemetry.

Why It Still Matters

The grant is a concrete early industrial-robot wrist architecture: actuators remain proximal while nested shafts and intersecting axes orient a distal tool. That topology still helps explain why robot designers care about wrist-center geometry, moving mass, internal transmissions, and the difference between orientation coverage and quantitative dynamic performance.

Formal Claims

A verified transcription of this record's formal claims is not available yet. Consult the pinned source PDF while the archival record remains under review.

The Historical Bottleneck

How can a programmable industrial robot orient an end effector over a broad continuous sector while keeping the distal wrist compact and driving it from motors mounted farther back on the arm?

Why Prior Art Failed

  • •The specification divides prior robots into link-and-pivot, extending-link, and serial rotary-shaft designs, and seeks greater orientational and positional range from the latter architecture.
  • •The source says mechanical interference in prior serial-drive arrangements interrupted continuous roll and left holes in the available spatial orientation.
The Breakthrough Insight
“Stackhouse arranged serial rotary shafts so the preferred three axes meet at a point and used nested shafts plus bevel gears to transmit three elbow-mounted hydraulic motor inputs through the moving wrist.”
Civilizational Impact
The patent documents the transition from dedicated machinery toward reprogrammable industrial manipulators and preserves a mechanically explicit solution to broad end-effector orientation.
Technological Lineage & Descent

Robotic Manipulation & Kinematic Degrees of Freedom

From Nuclear Hot-Cell Teleoperation to Parallel Delta Delta Manipulators

The kinematics and robotics lineage that transformed remote mechanical linkages into programmable magnetic-drum arms, selective-compliance SCARA robots, and high-speed delta mechanisms.

1958Bilateral Force-Reflecting Teleoperation
US 2,846,084

Goertz Force-Reflecting Master–Slave Manipulator

Position-error servomechanisms returning remote contact force feedback to human operator.

1961Programmable Robotic Manipulator
US 2,988,237

Devol Programmed Article-Transfer Controller

Magnetic recording drum storing multi-axis coordinate trajectories for playback.

1963Automated Visual Inspection
US 3,081,379

Lemelson Machine Vision & Automated Video Inspection

Video scanning raster signal comparison against reference templates for parts inspection.

1965Continuous Hydraulic Articulation
US 3,212,649

AMF Versatran Programmed Manipulator

Hydraulic servo actuation delivering coordinated multi-axis industrial transfer movements.

19786-DOF Anthropomorphic ArmThis Patent
US 4,068,536

Stackhouse Intersecting-Axis Robot Wrist

Electrically actuated revolute joints mimicking the human shoulder, elbow, and 3-axis wrist.

1978Remote-Center Passive Compliance
US 4,098,001

Watson Passive Remote-Center Compliance End Effector

Geometric elastic shear pads placing the center of compliance at the tip of the inserted peg.

1982Selective Compliance (SCARA)
US 4,341,502

Makino Four-Link SCARA Assembly Robot

Rigid vertical axis combined with compliant horizontal planar articulation for assembly.

1985Automatic Robotic Tool Changer
US 4,512,709

Milacron Robot Toolchanger: Common Base, Pins, and Wedge Lock

Precision kinematic docking interface transferring pneumatic, electrical, and mechanical tools.

1990High-Speed Parallel Delta Kinematics
US 4,976,582

Clavel Delta Parallel Robot

Three closed-loop parallelograms moving a lightweight traveling plate with high acceleration.

2003Autonomous Mobile Spatial Navigation
US 6,594,844

Optical Cliff and Wall Detection for an Autonomous Cleaning Robot

Dual differential drive wheels and sensor-guided state machine traversing unmapped rooms.