# US 2017/0282330 A1 · Elastic biasing element and encoder arrangement for precise control of force or torque > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0282330 A1 - Document ID: US20170282330A1 - Status: Published application - Kind: A1 - Application number: 15/508,711 - Filed: 2015-09-04 - Published: 2017-10-05 - Earliest claimed: 2014-09-04 - Assignees: Sunnen Products Company - Applicants: Sunnen Products Company - Inventors: John Harte; Daniel R. Cloutier; Mark Maichel - Web page: https://patentgrep.com/patent/US20170282330A1 ## CPC - B24B 49/16: taking regard of the load - B24B 33/02: designed for working internal surfaces of revolution, e.g. of cylindrical or conical shapes - B24B 33/087: {provided with measuring equipment} - B24B 47/20: relating to feed movement - B24B: MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING (grinding of gear teeth B23F, of screw-threads B23G1/36; by electro-erosion B23H; abrasive or related blasting B24C; tools for grinding, buffing or sharpening B24D; polishing compositions C09G1/00; abrasives C09K3/14; electrolytic etching or polishing C25F3/00; grinding arrangements for use on assembled railway tracks E01B31/17); DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS ## Abstract An apparatus, system, and method using an elastic biasing element in combination with an encoder arrangement for precise control of force or torque applied to a moving object, is applied for controlling a feed force applied to an abrasive element of a bore finishing tool, to respond to changes in the feed force such as can arise from contact with a workpiece bore surface and variations therein, such as tapers, hourglass shapes, barrel shapes, and the like. The elastic biasing element can include a single or multiple springs in one or more sets, and the feed force can be selected to have a constant value or vary as a function of time, position, or other variables or conditions. ## Claims ### Claim 1 A feed system for a feeding and applying a feed force to an abrasive element of a bore finishing tool in a lateral direction relative to an axis of rotation thereof, comprising: a drive apparatus controllably operable to move a drive element in a first direction and an opposite second direction within a predetermined range; an elastic biasing element having a first end and a second end, the first end disposed in predetermined relation to the drive element so as to be displaced by the movement thereof to cause the biasing element to elastically store a quantity of energy proportional to the displacement and representative of the feed force, and the second end being disposed in predetermined relation to an output element disposed to move generally axially in cooperation with a feed element of the bore finishing tool to transfer and apply the feed force laterally to the abrasive element and to displace jointly with the output element responsive to changes in the applied force; and a first sensor positioned and operable to determine a value representative of the displacement of the second end of the biasing element and output a signal representative thereof, a second sensor positioned and operable to determine a value representative of the displacement of the first end of the biasing element and output a signal representative thereof, and a processor connected to the first sensor and to the second sensor to receive the signals outputted thereby and to determine a responsive value for moving drive element of the drive apparatus to apply a selected feed force. ### Claim 2 (depends on 1) The feed system of claim 1, wherein the processor is connected in operative control of the drive apparatus. ### Claim 3 (depends on 1) The feed system of claim 1, wherein the drive apparatus comprises a servomotor and apparatus to translate rotary motion thereof to linear motion. ### Claim 4 (depends on 1) The feed system of claim 1 wherein the first sensor and the second sensor comprise encoders, respectively. ### Claim 5 (depends on 1) The feed system of claim 1, wherein the second sensor comprises an encoder incorporated into the drive apparatus. ### Claim 6 (depends on 1) The feed system of claim 1, comprising at least two of the elastic biasing elements. ### Claim 7 (depends on 6) The feed system of claim 6, wherein the biasing elements have different spring constant values. ### Claim 8 (depends on 1) The feed system of claim 1, wherein the elastic biasing element comprises multiple biasing elements arranged in sets. ### Claim 9 (depends on 1) The feed system of claim 1, wherein the biasing element comprises a spring. ### Claim 10 (depends on 1) The feed system of claim 1, wherein the elastic biasing element is selected from a group comprising at least one elastically compressible biasing element, at least one elastically tensionable biasing element, and a combination of at least one elastically compressible biasing element and at least one elastically tensionable biasing element. ### Claim 11 (depends on 10) The feed system of claim 10, wherein the elastic biasing element comprises at least one biasing element that has an elasticity property variable as a function of the displacement of one or both of the ends thereof. ### Claim 12 (depends on 11) The feed system of claim 11, wherein the elastic biasing element comprises at least one variable pitch spring. ### Claim 13 (depends on 1) The feed system of claim 1, further comprising a locking mechanism positioned and operable such that the displacement of the first end of the biasing element will directly move the output element to apply the feed force. ### Claim 14 (depends on 1) The feed system of claim 1, wherein the drive apparatus comprises a linear drive. ### Claim 15 (depends on 14) The feed system of claim 14, wherein the linear drive comprises a fluid cylinder. ### Claim 16 (depends on 14) The feed system of claim 14, wherein the linear drive comprises a linear motor. ### Claim 17 (depends on 1) The feed system of claim 1, wherein the selected feed force is controlled at least in part using a function based on at least one variable selected from a group consisting of at least time and position. ### Claim 18 (depends on 1) The feed system of claim 1, wherein the bore finishing tool comprises a honing tool. ### Claim 19 A method of controlling a feed force applied to an abrasive element of a bore finishing tool laterally relative to an axis of rotation of the tool, comprising steps of: providing a drive apparatus controllably operable to move a drive element in a first direction and an opposite second direction within a predetermined range; providing an elastic biasing element having a first end and a second end, the first end disposed in predetermined relation to the drive element so as to be displaced by the movement thereof to cause the biasing element to elastically store a quantity of energy proportional to the displacement and representative of the feed force, and the second end being disposed in predetermined relation to an output element disposed to move generally axially in cooperation with an element of the bore finishing tool to transfer and apply the feed force laterally to the abrasive element and to transfer changes in the applied force from the abrasive element to the second end of the biasing element so as to cause displacement thereof representative of the changes; and during rotation of the tool in a bore with the abrasive element in contact with a surface bounding the bore, controlling the drive apparatus to move the drive element as required to variably displace the first end of the biasing element responsive to changes in the applied feed force as represented by displacements of the second end thereof, to apply a predetermined feed force to the abrasive element. ### Claim 20 (depends on 19) The method of claim 19, wherein the step of controlling the drive apparatus comprises sensing positions representative of positions of the first and second ends of the biasing element in a generally continuous manner to determine the responsive movements of the drive element to be made.