# US 2017/0254367 A1 · Wave actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0254367 A1 - Document ID: US20170254367A1 - Status: Published application - Kind: A1 - Application number: 15/598,149 - Filed: 2017-05-17 - Published: 2017-09-07 - Earliest claimed: 2015-04-15 - Assignees: Genesis Robotics LLP - Applicants: Genesis Robotics LLP - Inventors: James Brent Klassen - Web page: https://patentgrep.com/patent/US20170254367A1 ## CPC - F16D 11/14: with clutching members movable only axially (F16D11/02, F16D11/08 take precedence) - F16D 13/22: with axially-movable clutching members (similar brakes F16D55/00) - F16D 13/64: Clutch-plates; Clutch-lamellae (brake-plates, brake-lamellae F16D65/12) - F16D 27/004: {with permanent magnets combined with electromagnets} - H02N 2/10: producing rotary motion, e.g. rotary motors - F16D 2011/008: {characterised by the form of the teeth forming the inter-engaging parts; Details of shape or structure of these teeth} - F16D 2500/1022: Electromagnet - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES - H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR ## Abstract A two dimensional structure such as a disk or belt is shaped or distorted to form a buckling wave. At least one contact touches the wave, with two contacts squeezing the wave between them providing a firmer connection. The wave is propagated along the structure by any of a variety of means including magnets or piezo actuators. This movement of the wave moves the contacts relative to the two dimensional structure, providing a high leverage ratio. ## Claims ### Claim 1 A wave actuator comprising: a two dimensional structure having at least a portion pre-stressed in compression in a first direction of the two dimensional structure to form a wave shape having waves along the first direction; an output arranged in contact with the waves of the wave shape, the output and the two-dimensional structure movably arranged in relation to one another; and a wave propagator arranged to propagate the waves along the first direction to move the output relative to the two dimensional structure. ### Claim 2 (depends on 1) The wave actuator of claim 1 in which the output comprises a first output member and a second output member, the wave shape being constrained between the first output member and the second output member. ### Claim 3 (depends on 2) The wave actuator of claim 2 in which the first output member is rigidly connected to the second output member. ### Claim 4 (depends on 2) The wave actuator of claim 2 in which the wave shape comprises a first contact surface that contacts the first output member and a second contact surface that contacts the second output member, one of the contact surfaces being offset in a direction generally perpendicular to the two-dimensional structure to cause the wave actuator to differentially move the first output member and the second output member. ### Claim 5 (depends on 4) The wave actuator of claim 4 further comprising a slot in the one of the contact surface that is offset in the direction generally perpendicular to the two-dimensional structure. ### Claim 6 (depends on 1) The wave actuator of claim 1 in which the wave propagator comprises piezo actuators attached to the two dimensional structure and aligned within the two dimensional structure generally perpendicular to the first direction. ### Claim 7 (depends on 1) The wave actuator of claim 1 in which the wave propagator comprises electromagnets. ### Claim 8 (depends on 1) The wave actuator of claim 1 in which the output is in friction contact with the waves of the wave shape. ### Claim 9 (depends on 1) The wave actuator of claim 1 in which the output is in geared contact with the waves of the wave shape. ### Claim 10 (depends on 1) The wave actuator of claim 1 further comprising a reference member, the wave shape being constrained between the output and the reference member. ### Claim 11 (depends on 2) The wave actuator of claim 2 in which the wave shape is compressed between the output members to create two or more contact patches on the first output member and an equal number of contact patches on the second output member. ### Claim 12 (depends on 11) The wave actuator of claim 11 in which the first output member and the second output member compress the wave shape with sufficient contact pressure to create flattened portions of the two dimensional structure where the two dimensional structure contacts the first output member and the second output member. ### Claim 13 (depends on 1) The wave actuator of claim 1 further comprising grooves extending generally in the first direction in each of the disk and the output. ### Claim 14 (depends on 13) The wave actuator of claim 13 in which the grooves have angled shapes to increase the contact pressure as a result of loading of the disk against the output. ### Claim 15 (depends on 1) The wave actuator of claim 1 in which the two dimensional structure comprises a first material having a first coefficient of thermal expansion, and a second material having a second coefficient of thermal expansion, the first coefficient of thermal expansion being different from the second coefficient of thermal expansion, the two dimensional structure being formed at a first temperature and used at a second temperature to pre-stress the two dimensional structure in use. ### Claim 16 (depends on 1) The wave actuator of claim 1 in which the two dimensional structure is a belt. ### Claim 17 (depends on 16) The wave actuator of claim 16 in which an edge portion along an edge of the belt is pre-stressed in compression by a tension member applying a compressive force parallel to the edge to a portion of the belt parallel to but offset from the edge. ### Claim 18 (depends on 1) The wave actuator of claim 1 in which the two dimension structure comprises an arc and the pre-stressed portion is an edge portion at an outer edge of the arc, the edge portion pre-stressed in compression tangentially to the edge. ### Claim 19 A method of making a wave actuator, the method comprising: providing a disk with a circumference in an initial state; loading the disk in tension across the disk and compression along the circumference to cause the disk to buckle and form a wave shape with waves; and constraining the disk between output members with the output members contacting the disk at one or more wave apexes such that force can be transferred from the disk to the output members when a wave is propagated along the disk. ### Claim 20 (depends on 19) The method of claim 19 in which the output members contact the disk on both sides of the disk. ### Claim 21 (depends on 19) The method of claim 19 further comprising the output member exerting enough force on the disk to increase the number of waves from the initial state when the circumference is loaded in compression and before contacting the output members. ### Claim 22 (depends on 19) The method of claim 19 further comprising providing the disk and output members with teeth and meshing respective teeth of the disk and output members. ### Claim 23 (depends on 19) The method of claim 19 in which loading the disk in tension across the disk and compression along the circumference comprises providing the disk with a ring, and the disk and ring being made of materials of different coefficients of thermal expansion, and subjecting the disk to a temperature set to cause the disk and ring to contract differentially. ### Claim 24 (depends on 19) The method of claim 19 in which subjecting the disk to a temperature comprises placing the disk in an injection mold. ### Claim 25 A torque transfer device comprising: a wave disk, the wave disk having an axis, the wave disk being preloaded in tension radially and in compression along the outer circumference such that a circumferential buckling effect is produced to generate an axial wave with two or more wave crests and troughs; one or more output contact rings attached coaxially to a rotating output member and axially preloaded against the axial wave apexes; and a propagating means to circumferentially propagate the wave to impart rotation and torque from the wave disk to the output members. ### Claim 26 (depends on 25) The torque transfer device of claim 25 further comprising traction surfaces on the contacts. ### Claim 27 (depends on 25) The torque transfer device of claim 25 further comprising lobed surfaces on the contacts. ### Claim 28 (depends on 27) The torque transfer device of claim 27 further comprising elongated lobes on the wave disk which splay apart just before full engagement in the mating lobes on the output member lobed rings. ### Claim 29 (depends on 25) The torque transfer device of claim 25 in which the propagating means comprises commutated electromagnets. ### Claim 30 (depends on 25) The torque transfer device of claim 25 in which the propagating means comprises piezo actuators.