How a Surgical Robot Arm's Wrist Moves Instruments
This patent describes a specific design for the end part of a surgical robot arm, called the terminal portion, which uses a clever arrangement of three joints to precisely position and rotate surgical tools.
Original patent title: “Surgical arm”
This patent describes a specific design for the end part of a surgical robot arm, called the terminal portion, which uses a clever arrangement of three joints to precisely position and rotate surgical tools. Granted to CMR Surgical in 2025 with 19 claims, and it is expected to expire in 2041.
Coverage
What does this patent actually cover?
The patent describes a specialized "terminal portion" for a surgical robot arm, which is like the robot's wrist. This portion has three main parts: a "distal segment" that holds the surgical tool, an "intermediate segment" in the middle, and a "basal segment" that connects to the rest of the arm (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1). It uses three articulations, or joints, to move the tool. A "first articulation" lets the tool rotate around its own axis (the "first axis") relative to the intermediate segment. A "second articulation" lets the intermediate segment rotate relative to the basal segment around a "second axis." The "intermediate segment" itself contains a "third articulation" that allows the distal segment and the tool to rotate about "third and fourth axes" (Claim 1). The clever part is how these joints are arranged: in a straight position, the first and second axes line up, and the third and fourth axes cross each other and are perpendicular to the first axis (Claim 1). This allows the robot to precisely control the instrument's position and orientation. For example, a surgeon could use this arm to precisely rotate a scalpel while also angling it for a delicate cut, all through the coordinated movement of these three joints.
The gap
What does this patent NOT cover?
- Robot arms where the surgical instrument is not detachably attached to a single connector on the distal segment.
- Surgical robot arms that do not have the specific arrangement of first, second, and third articulations as defined in ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1, especially regarding the collinearity and transverseness of the axes in a straight configuration.
- Robot arms where the intermediate segment does not contain a third articulation that allows rotation about third and fourth axes.
- Surgical robot arms where the connector for the instrument can articulate relative to the basal segment using more than just the first, second, and third articulations.
- Robot arms where the first and second axes are not collinear in a straight configuration of the terminal portion.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The noveltynoveltyThe requirement that an invention be different from anything publicly known before its priority date.Read more → lies in the specific kinematic arrangement of the three articulations within the terminal portion, particularly how the first, second, third, and fourth axes are configured to be collinear and transverse in a straight configuration. This allows for a compact and highly dexterous "wrist" mechanism for surgical instruments.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
CMR Surgical Versius surgical robot system
Intuitive Surgical da Vinci surgical system
Medtronic Hugo RAS system
Minimally invasive surgical robots
Why it matters
The bigger picture
Precise control over surgical instruments is critical for minimally invasive surgery, where surgeons operate through small incisions. This patent aims to improve the dexterity and range of motion of robotic surgical arms, potentially allowing for more complex procedures to be performed robotically. Better articulation in the robot's "wrist" can reduce the need for larger incisions or more complex movements of the entire robot arm, leading to better patient outcomes.
Filed
December 6, 2021
Granted
September 16, 2025
Market context
Who's building on this
Companies in this space
CMR Surgical Ltd, the assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, is actively developing and deploying surgical robotic systems like the Versius, which would incorporate such arm designs. Other major players in surgical robotics, such as Intuitive Surgical and Medtronic, are also continually innovating in robot arm dexterity and instrument control. These companies are all working to enhance the precision and flexibility of robotic tools for surgeons.
Market impact
This type of innovation contributes to the ongoing advancement of robotic-assisted surgery. By offering improved dexterity and precision at the instrument tip, it can enable surgeons to perform more complex and delicate procedures minimally invasively. This can expand the types of surgeries suitable for robotic assistance, potentially increasing patient access to less invasive treatments and driving demand for advanced robotic platforms in healthcare.
Claim 1 — Plain English
What this patent covers
The patent describes a specialized "terminal portion" for a surgical robot arm, which is like the robot's wrist. This portion has three main parts: a "distal segment" that holds the surgical tool, an "intermediate segment" in the middle, and a "basal segment" that connects to the rest of the arm (Claim 1). It uses three articulations, or joints, to move the tool. A "first articulation" lets the tool rotate around its own axis (the "first axis") relative to the intermediate segment. A "second articulation" lets the intermediate segment rotate relative to the basal segment around a "second axis." The "intermediate segment" itself contains a "third articulation" that allows the distal segment and the tool to rotate about "third and fourth axes" (Claim 1). The clever part is how these joints are arranged: in a straight position, the first and second axes line up, and the third and fourth axes cross each other and are perpendicular to the first axis (Claim 1). This allows the robot to precisely control the instrument's position and orientation. For example, a surgeon could use this arm to precisely rotate a scalpel while also angling it for a delicate cut, all through the coordinated movement of these three joints.
The clever bit
The novelty lies in the specific kinematic arrangement of the three articulations within the terminal portion, particularly how the first, second, third, and fourth axes are configured to be collinear and transverse in a straight configuration. This allows for a compact and highly dexterous "wrist" mechanism for surgical instruments.
What it does not cover
- Robot arms where the surgical instrument is not detachably attached to a single connector on the distal segment.
- Surgical robot arms that do not have the specific arrangement of first, second, and third articulations as defined in Claim 1, especially regarding the collinearity and transverseness of the axes in a straight configuration.
- Robot arms where the intermediate segment does not contain a third articulation that allows rotation about third and fourth axes.
- Surgical robot arms where the connector for the instrument can articulate relative to the basal segment using more than just the first, second, and third articulations.
- Robot arms where the first and second axes are not collinear in a straight configuration of the terminal portion.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
PatentBrief Score
Impact Score
Early stage
Citation count
0/40
No citations yet
Claim breadth
13/20
Broad claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
20/20
Granted within 5 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$64K – $206K
Midpoint $129K · 15.4 yr remaining · industry ×2.2
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
19 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Randle, S. J., & Hares, L. D. R. (2025). How a Surgical Robot Arm's Wrist Moves Instruments (U.S. Patent No. 12,414,825). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/12414825/surgical-arm
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How a Surgical Robot Arm's Wrist Moves Instruments cover?
This patent describes a specific design for the end part of a surgical robot arm, called the terminal portion, which uses a clever arrangement of three joints to precisely position and rotate surgical tools.
Who owns patent US 12414825?
CMR Surgical owns this patent, granted in 2025.
When does this patent expire?
This patent is expected to expire on December 6, 2041, when the invention enters the public domain.
What problem does this patent solve?
Precise control over surgical instruments is critical for minimally invasive surgery, where surgeons operate through small incisions. This patent aims to improve the dexterity and range of motion of robotic surgical arms, potentially allowing for more complex procedures to be performed robotically. Better articulation in the robot's "wrist" can reduce the need for larger incisions or more complex movements of the entire robot arm, leading to better patient outcomes.
What does this patent NOT cover?
Robot arms where the surgical instrument is not detachably attached to a single connector on the distal segment.
Patent monitoring