# US 10,371,232 B2 · Torque reaction in rotating medical apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,232 B2 - Document ID: US10371232B2 - Status: Granted - Kind: B2 - Application number: 15/484,336 - Filed: 2017-04-11 - Published: 2017-10-12 - Granted: 2019-08-06 - Earliest claimed: 2017-04-11 - Assignees: Elekta Limited - Applicants: Elekta Limited - Inventors: Per Harald Bergfjord - Web page: https://patentgrep.com/patent/US10371232B2 ## CPC - F16F 15/30: Flywheels (F16F15/16, F16F15/28 take precedence; suppression of vibrations in rotating systems using elastic members or friction-damping members moving with the system, {i.e. split flywheels or single masses connected to a hub by elastic members or friction-damping members} F16F15/12; rotary-body aspects in general F16C13/00, F16C15/00) - A61B 6/035: {Mechanical aspects of CT} - A61B 6/4435: {the source unit and the detector unit being coupled by a rigid structure} - A61C 1/186: {with torque adjusting or limiting means} - A61N 5/01: Devices for producing movement of radiation source during therapy {(A61N5/1077 takes precedence)} - A61N 5/1081: {Rotating beam systems with a specific mechanical construction, e.g. gantries} - H02K 7/02: Additional mass for increasing inertia, e.g. flywheels - F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00) - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract A system and method for compensating for torque reaction forces in a medical apparatus is disclosed. The system may include a rotary element which rotates about an axis. A contra-rotating flywheel may be driven to rotate about the axis relative to the rotary element, wherein the flywheel is free to rotate and is accelerated and decelerated by a driver which is fixed to the rotary element. Contra-rotation of the flywheel may compensate for torque reaction forces when the rotary element is accelerated or decelerated. ## Claims ### Claim 1 A system for use with a medical apparatus having a rotary element which rotates about an axis, the system comprising: a contra-rotating flywheel which is driven to rotate about the axis relative to the rotary element, wherein the flywheel is free to rotate and is accelerated and decelerated by a driver which is fixed to the rotary element. ### Claim 2 (depends on 1) The system according to claim 1, wherein the flywheel is located within an axial length of the rotary element. ### Claim 3 (depends on 1) The system according to claim 1, wherein the rotary element is cylindrical. ### Claim 4 (depends on 3) TL system according to claim 3, wherein the flywheel has an outer circumference larger in diameter than an internal diameter of the cylindrical rotary element. ### Claim 5 (depends on 4) The system according to claim 4, wherein the outer circumference of the flywheel is smaller than an external diameter of the cylindrical rotary element. ### Claim 6 (depends on 1) The system according to claim 1, wherein the rotary element is a C-arm apparatus. ### Claim 7 (depends on 1) The system according to claim 1, further comprising one or more motors for driving the flywheel relative to the rotary element. ### Claim 8 (depends on 1) The system according to claim 1, wherein the flywheel comprises a rotor of an electric motor and the rotary element comprises a stator of the electric motor. ### Claim 9 (depends on 1) The system according to claim 1, further comprising one or more brakes configured to selectively decelerate the rotation of the flywheel relative to the rotary element. ### Claim 10 (depends on 1) The system according to claim 1, wherein the flywheel has a mass and/or a moment of inertia less than that of the rotary element. ### Claim 11 (depends on 1) The system according to claim 1, further comprising a processor for controlling the rotation of the rotary element and the contra-rotation of the flywheel. ### Claim 12 A method of compensating for torque reaction forces in a medical apparatus comprising a rotary element which rotates around an axis, the method comprising: driving a contra-rotating flywheel relative to the rotary element, wherein the flywheel rotates around the axis in the opposite direction of the rotary element, and wherein the flywheel is free to rotate and is accelerated and decelerated by a driver which is fixed to the rotary element. ### Claim 13 (depends on 12) The method according to claim 12, wherein the flywheel is driven to rotate at a different angular velocity than the rotary element. ### Claim 14 (depends on 13) The method according to claim 13, wherein the flywheel is driven to rotate at a higher angular velocity than the rotary element. ### Claim 15 (depends on 1) The system according to claim 1, wherein the medical apparatus is one of a medical treatment apparatus, an imaging apparatus, or a dental apparatus. ### Claim 16 (depends on 1) The system according to claim 1, wherein the rotary element is a hollow drum configured for receiving a patient therein. ### Claim 17 (depends on 16) The system according to claim 16, wherein the flywheel is annular. ### Claim 18 (depends on 1) The system according to claim 1, wherein the rotary element is a closed drum configured for rotating a gantry arm about a patient. ### Claim 19 (depends on 18) The system according to claim 18, wherein the gantry arm has a treatment or imaging device mounted thereon. ### Claim 20 (depends on 1) The system according to claim 1, wherein a treatment or imaging device is mounted upon an internal circumference of the rotary element.