# US 11,896,439 B2 · Load sensing devices for use in surgical instruments > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,896,439 B2 - Document ID: US11896439B2 - Status: Granted - Kind: B2 - Application number: 17/549,079 - Filed: 2021-12-13 - Published: 2022-03-31 - Granted: 2024-02-13 - Earliest claimed: 2018-10-30 - Assignees: Covidien LP - Applicants: Covidien LP - Inventors: Matthew Eschbach - Web page: https://patentgrep.com/patent/US11896439B2 ## CPC - A61B 90/06: {Measuring instruments not otherwise provided for} - A61B 17/07207: {the staples being applied sequentially} - A61B 2017/00017: {Electrical control of surgical instruments} - A61B 2017/0003: {of parts of the instruments} - A61B 2017/00398: {using powered actuators, e.g. stepper motors, solenoids} - A61B 2017/0046: {with a releasable handle; with handle and operating part separable} - A61B 2017/00473: {Distal part, e.g. tip or head (A61B2017/00464 takes precedence)} - A61B 2017/07257: {characterised by its anvil} - A61B 2017/07271: {characterised by its cartridge} - A61B 2090/064: {for measuring force, pressure or mechanical tension} - A61B 2562/0261: Strain gauges - A61B 2562/164: the sensor is mounted in or on a conformable substrate or carrier - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A surgical end effector includes an anvil assembly; a cartridge assembly including a plurality of fasteners; a drive assembly movable longitudinally to approximate the anvil assembly relative to the cartridge assembly; and a strain gauge circuit disposed within the cartridge assembly, the strain gauge circuit configured to measure a strain imparted on the cartridge assembly by the drive assembly. ## Claims ### Claim 1 A surgical end effector comprising: a housing a drive assembly movable within the housing; a strain gauge circuit disposed within the housing, the strain gauge circuit configured to measure a strain imparted on the housing by the drive assembly, the strain gauge circuit includes a flexible circuit, the flexible circuit having: a first flexible dielectric substrate; a resistive sensor layer disposed over the first flexible dielectric substrate; a conductive layer disposed over the resistive sensor layer; and a second flexible dielectric substrate disposed over the resistive sensor layer and the conductive layer. ### Claim 2 (depends on 1) The surgical end effector according to claim 1, wherein the resistive sensor layer includes a strain gauge and a continuous layer. ### Claim 3 (depends on 2) The surgical end effector according to claim 2, the conductive layer includes a first conductive trace and a second conductive trace, each of which is coupled to the strain gauge. ### Claim 4 (depends on 3) The surgical end effector according to claim 3, wherein the strain gauge includes a continuous trace having a first end and a second end, the first end coupled to the first conductive trace and the second end coupled to the second conductive trace. ### Claim 5 (depends on 4) The surgical end effector according to claim 4, wherein the strain gauge has a variable gauge factor. ### Claim 6 (depends on 5) The surgical end effector according to claim 5, wherein the strain gauge includes a pair of parallel grid lines, each of which has a tapered shape thereby providing the variable gauge factor. ### Claim 7 (depends on 6) The surgical end effector according to claim 6, wherein the strain gauge includes a plurality of grid lines of varying length providing the variable gauge factor. ### Claim 8 (depends on 1) The surgical end effector according to claim 1, further comprising: an anvil assembly; and a cartridge assembly including a plurality of fasteners. ### Claim 9 (depends on 8) The surgical end effector according to claim 8, wherein the drive assembly is configured to move at least one of the anvil assembly or the cartridge assembly relative to each other. ### Claim 10 A surgical end effector comprising: a housing; a drive assembly movable within the housing; and a strain gauge circuit disposed within the housing, the strain gauge circuit configured to measure a strain imparted on the housing by the drive assembly, the strain gauge circuit includes a strain gauge portion and a lead portion having a slack portion with at least one turn. ### Claim 11 (depends on 10) The surgical end effector according to claim 10, further comprising: an anvil assembly; and a cartridge assembly including a plurality of fasteners. ### Claim 12 (depends on 11) The surgical end effector according to claim 11, wherein the drive assembly is configured to move at least one of the anvil assembly or the cartridge assembly relative to each other. ### Claim 13 A surgical instrument comprising: a handle assembly including a controller and a power source; a longitudinal shaft including a proximal end portion coupled to the handle assembly and a distal end portion; and a surgical end effector having: a housing; a drive assembly movable within the housing; and a strain gauge circuit disposed within the housing and electrically coupled to the controller and the power source, the strain gauge circuit configured to measure a strain imparted on the housing by the drive assembly and to transmit a measurement signal to the controller, the strain gauge circuit includes a flexible circuit, the flexible circuit having: a first flexible dielectric substrate; a resistive sensor layer disposed over the first flexible dielectric substrate; a conductive layer disposed over the resistive sensor layer; and a second flexible dielectric substrate disposed over the resistive sensor layer and the conductive layer. ### Claim 14 (depends on 13) The surgical instrument according to claim 13, wherein the resistive sensor layer includes a strain gauge and a continuous layer. ### Claim 15 (depends on 14) The surgical instrument according to claim 14, the conductive layer includes a first conductive trace and a second conductive trace, each of which is coupled to the strain gauge. ### Claim 16 (depends on 15) The surgical instrument according to claim 15, wherein the strain gauge includes a continuous trace having a first end and a second end, the first end coupled to the first conductive trace and the second end coupled to the second conductive trace. ### Claim 17 (depends on 16) The surgical instrument according to claim 16, wherein the strain gauge includes a variable cross-section. ### Claim 18 (depends on 17) The surgical instrument according to claim 17, wherein the strain gauge includes a pair of parallel grid lines, each of which has a tapered shape thereby providing the variable cross-section. ### Claim 19 (depends on 17) The surgical instrument according to claim 17, wherein the strain gauge includes a plurality of grid lines of varying length providing the variable cross-section.