# How an Exoskeleton Joint Moves with a Motor, Screw, and Linkage > This patent describes a compact and efficient way to make an exoskeleton joint bend and straighten using a motor, a special screw, and a clever set of levers. - **Patent:** US 11673253 - **Original title:** Actuator devices for human exoskeleton joints - **Owner:** Ekso Bionics - **Granted:** 2023 - **Status:** Active - **Times cited:** 1 - **Field:** robotics, medical_devices, mechanical, biotech, consumer_electronics ## What it does This patent details an actuator mechanism for an exoskeleton joint. It connects a first support (like a thigh brace) and a second support (like a shin brace) to a wearer. The actuator uses a motor (claim 1) that spins a 'ball screw' (claim 1). This screw then moves a 'ball nut' along its length, which in turn pushes or pulls a 'yoke' (claim 1). The yoke is designed to move only in a straight line, acting like a slider (claim 1). This straight-line motion of the yoke then pushes or pulls a 'linkage,' which is a rod or bar (claim 1). Finally, the linkage causes a 'joint crank' to rotate around the exoskeleton's main joint (claim 1), making the two supports move relative to each other, like bending a knee. For example, as the motor spins, the yoke slides, pushing the linkage, which rotates the joint crank to bend the exoskeleton's knee joint. ## What it does NOT cover - Does not cover exoskeleton joints that use direct rotary motors without a ball screw and linkage system. - Does not cover actuators where the yoke rotates or moves in a non-linear fashion, as it specifies the yoke moves 'only in translation' (claim 1). - Does not cover systems where the motor, ball screw, ball nut, and yoke are not arranged collinearly (claim 1). - Does not cover actuators that rely on hydraulic or pneumatic cylinders instead of a motor and ball screw mechanism. - Does not cover a roller and joint cam system, as described in the abstract, if it does not also include the linkage and joint crank as claimed (claim 1). ## The clever bit The novelty lies in the specific combination and arrangement of components: using a ball screw to translate a yoke, which then acts as a slider to drive a linkage and joint crank. This efficiently converts linear motion into powerful rotational motion at the joint, while constraining the yoke to pure translation for reliability. ## Real-world examples 1. Ekso Bionics EksoNR exoskeleton 2. Powered prosthetic limbs 3. Industrial assist exoskeletons 4. Robotic rehabilitation devices ## Why it matters Exoskeletons need powerful yet precise ways to move their joints to help people walk or lift heavy objects. This patent focuses on a specific mechanical design for these actuators, aiming for efficiency and control. The design elements, such as the ball screw and linkage, are critical for translating a motor's rotation into the strong, controlled bending and straightening motions required for human assistance or augmentation. ## Frequently asked questions ### What does How an Exoskeleton Joint Moves with a Motor, Screw, and Linkage cover? This patent describes a compact and efficient way to make an exoskeleton joint bend and straighten using a motor, a special screw, and a clever set of levers. ### Who owns patent US 11673253? Ekso Bionics owns this patent, granted in 2023. ### When does this patent expire? This patent is expected to expire on March 7, 2038, when the invention enters the public domain. ### What is patent US 11673253 cited by? This patent has been cited by 1 later patents that build on its ideas. ### What problem does this patent solve? Exoskeletons need powerful yet precise ways to move their joints to help people walk or lift heavy objects. This patent focuses on a specific mechanical design for these actuators, aiming for efficiency and control. The design elements, such as the ball screw and linkage, are critical for translating a motor's rotation into the strong, controlled bending and straightening motions required for human assistance or augmentation. ### What does this patent NOT cover? Does not cover exoskeleton joints that use direct rotary motors without a ball screw and linkage system. **Full plain-English explainer:** https://patentbrief.org/patent/us/11673253/actuator-devices-for-human-exoskeleton-joints **Original patent:** https://patents.google.com/patent/US11673253 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How Exoskeletons Use Screws and Cables to Move Joints](https://patentbrief.org/patent/us/10702441/ball-screw-and-tensile-member-exoskeleton-joint-actuation-device) — This patent describes a mechanical system for exoskeletons that uses a rotating screw to push a nut, which then pulls cables to make a joint bend or straighten. - [Flexible Footplate for Robotic Walking Assistance](https://patentbrief.org/patent/us/11304827/unidirectional-actuated-exoskeleton-device) — This patent describes a specialized composite footplate for footwear that includes a mechanical joint to help users with natural foot movements like pointing toes up or down, and rolling their ankles, especially when connected to an exoskeleton. - [How a Robotic Exoskeleton Helps Your Shoulder Move](https://patentbrief.org/patent/us/10800031/spherical-parallel-manipulator-architecture-for-shoulder-robotic-exoskeleton) — This patent describes a robotic shoulder exoskeleton using multiple straight-moving actuators arranged in a "spherical parallel manipulator" to assist or rehabilitate arm movements while preventing joint misalignment. - [Exoskeleton Shoulder Joint That Adapts to Your Arm's Movement](https://patentbrief.org/patent/us/10814473/mechanism-for-alleviating-the-effects-of-joint-misalignment-between-users-and-we) — This patent describes a shoulder exoskeleton that uses a special slip mechanism to prevent the robot's joints from getting out of sync with a user's natural arm movements, making it more comfortable and effective. - [How a Robot Actuator Controls Force and Speed with Gears](https://patentbrief.org/patent/us/8209052/high-performance-differential-actuator-for-robotic-interaction-tasks) — This patent describes a compact robot actuator that uses a special gear system and two motors with different electrical resistance to precisely control both the force and speed applied to a robotic arm or tool.