# US 11,440,212 B2 · Power tool > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,212 B2 - Document ID: US11440212B2 - Status: Granted - Kind: B2 - Application number: 16/896,926 - Filed: 2020-06-09 - Published: 2020-12-10 - Granted: 2022-09-13 - Earliest claimed: 2019-06-10 - Assignees: Nanjing Chervon Industry Co., Ltd. - Applicants: Nanjing Chervon Industry Co., Ltd. - Inventors: Dezhong Yang; Jifeng Feng; Li Pan - Web page: https://patentgrep.com/patent/US11440212B2 ## CPC - B25F 5/00: Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for - B27B 17/083: {Devices for arresting movement of the saw chain} - B23D 59/001: {Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade (measuring in general G01; controlling in general G05)} - B25F 5/02: Construction of casings, bodies or handles {(B25F5/006, B25F5/008 take precedence)} - B27G 19/003: {for chain saws (braking devices B27B17/08)} - H02P 29/032: Preventing damage to the motor, e.g. setting individual current limits for different drive conditions - B27B 17/02: Chain saws equipped with guide bar (B27B17/06 takes precedence) - B25F: COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR {(machines or arrangements of machines for performing specified combinations of different metal-working operations not covered by a single other subclass B23P23/00 and subgroups)} - B27B: SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR (saws specially adapted for pruning or debranching A01G3/08; sawing apparatus specially adapted for felling trees A01G23/091; features not restricted to a particular type of wood saw B23D, e.g. attaching saw blades B23D51/00; machine tool frames, beds, pillars or like members, in general B23Q1/01) - B23D: PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR (making toothed gears or the like B23F; cutting metal by applying heat locally B23K; arrangements for copying or controlling B23Q) - B27G: ACCESSORY MACHINES OR APPARATUS FOR WORKING WOOD OR SIMILAR MATERIALS; TOOLS FOR WORKING WOOD OR SIMILAR MATERIALS (tools for grinding B24D; sawing tools B27B33/00; tools for slotting or mortising machines B27F5/02; tools for the manufacture of wood shavings, chips, powder or the like B27L11/00); SAFETY DEVICES FOR WOOD WORKING MACHINES OR TOOLS - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract A power tool includes a function member, a motor, a driving circuit electrically connected to the motor to drive the motor, and a first control module configured to output a first control signal to the driving circuit. The first control module has a first working state and a first failure state. The first control module outputs a first working signal when the first control module is in the first working state, and outputs a first failure signal when the first control module is in the first failure state. A second control module is electrically connected to the first control module to receive the first working signal or the first failure signal from the first control module. The second control module outputs a second control signal to turn off the motor when the second control module receives the first failure signal from the first control module. ## Claims ### Claim 1 A power tool, comprising: a function member, configured to realize a function of the power tool; a motor, configured to drive the function member; a driving circuit, electrically connected to the motor and configured to drive the motor; a first control module, configured to output a first control signal to the driving circuit, wherein the first control module has a first working state and a first failure state, the first control module is configured to, in condition that the first control module is in the first working state, output a first working signal, and the first control module is further configured to, in condition that the first control module is in the first failure state, output a first failure signal; and a second control module, electrically connected to the first control module, wherein the second control module is configured to receive the first working signal or the first failure signal from the first control module, wherein the second control module is configured to, in response to receiving the first failure signal from the first control module, output a second control signal to turn off the motor, wherein the first control module and the second control module are in communication connection to each other, the second control module has a second working state and a second failure state, the second control module is configured to, in condition that the second control module is in the second working state, output a second working signal to the first control module, the second control module is further configure to, in condition that the second control module is in the second failure state, output a second failure signal to the first control module, and the first control module is configured to, in response to receiving the second failure signal from the second control module, output a first control signal to turn off the motor, and wherein the first failure state is associated with the condition of at least one of a first switch or a first sensor and the second failure state is associated with the condition of at least one of a second switch or a second sensor. ### Claim 2 (depends on 1) The power tool according to claim 1, further comprising a protection circuit, wherein the protection circuit is electrically connected to the second control module and is configured to, in response to receiving the second control signal from the second control module, turn off the motor. ### Claim 3 (depends on 2) The power tool according to claim 2, further comprising a power supply device configured to supply power to the power tool, wherein the protection circuit comprises a switch circuit, the switch circuit is configured to cut off an electrical connection between the motor and the power supply device, and the switch circuit comprises at least one electronic switch. ### Claim 4 (depends on 3) The power tool according to claim 3, wherein the protection circuit further comprises a switch control circuit, the switch control circuit is electrically connected to the switch circuit and the second control module, and the switch control circuit is configured to control on-off operations of the switch circuit according to the second control signal from the second control module so as to cut off the electrical connection between the motor and the power supply device. ### Claim 5 (depends on 4) The power tool according to claim 4, wherein the driving circuit comprises a plurality of driving switches, the switch circuit comprises a first electronic switch, the first electronic switch is electrically connected between control terminals of at least part of the plurality of driving switches and the first control module, the first electronic switch is configured to cut off electrical connections between the first control module and the control terminals of the at least part of the plurality of driving switches, the switch control circuit comprises a second electronic switch, the second electronic switch is electrically connected between a control terminal of the first electronic switch and the second control module, and the second electronic switch is configured to control the on-off operations of the first electronic switch according to the second control signal of the second control module so as to cut off the electrical connections between the first control module and the at least part of the plurality of driving switches, thereby cutting off the electrical connection between the motor and the power supply device. ### Claim 6 (depends on 3) The power tool according to claim 3, wherein the driving circuit comprises a plurality of driving switches, the switch circuit comprises a third electronic switch, the third electronic switch is electrically connected between control terminals of at least part of the plurality of driving switches and a ground lead, a control terminal of the third electronic switch is electrically connected to the second control module, and the third electronic switch is configured to switch on connections between the at least part of the plurality of driving switches and the ground lead according to the second control signal of the second control module so as to cut off the electrical connection between the motor and the power supply device. ### Claim 7 (depends on 1) The power tool according to claim 1, wherein the second control module comprises a control circuit and the control circuit comprises at least one switch element or the second control module comprises a microcontroller. ### Claim 8 (depends on 1) The power tool according to claim 1, further comprising a start switch configured to at least start the power tool, wherein the start switch is connected to the first control module, and the first control module is configured to, in condition that the first control module detects that the start switch is triggered and receives the second working signal from the second control module, output the first control signal to start the motor. ### Claim 9 (depends on 1) The power tool according to claim 1, further comprising a brake switch configured to brake the motor, wherein the brake switch is connected to the first control module, and the first control module is configured to, in condition that the first control module detects that the brake switch is triggered and receives the second working signal from the second control module, output the first control signal to the driving circuit so as to brake the motor. ### Claim 10 A chain saw, comprising: a saw chain, configured to realize a cutting function; a motor, configured to drive the saw chain; a driving circuit, electrically connected to the motor and configured to drive the motor; a first control module, configured to output a first control signal to the driving circuit, wherein the first control module has a first working state and a first failure state, the first control module is configured to, in condition that the first control module is in the first working state, output a first working signal, and the first control module is further configured to, in condition that the first control module is in the first failure state, output a first failure signal; and a second control module, electrically connected to the first control module, wherein the second control module is configured to receive the first working signal or the first failure signal from the first control module, wherein the second control module is configured to, in response to receiving the first failure signal from the first control module, output a second control signal to turn off the motor, wherein the first control module and the second control module are in communication connection to each other, the second control module has a second working state and a second failure state, the second control module is configured to, in condition that the second control module is in the second working state, output a second working signal to the first control module, the second control module is further configure to, in condition that the second control module is in the second failure state, output a second failure signal to the first control module, and the first control module is configured to, in response to receiving the second failure signal from the second control module, output a first control signal to turn off the motor, and wherein the first failure state is associated with the condition of at least one of a first switch or a first sensor and the second failure state is associated with the condition of at least one of a second switch or a second sensor. ### Claim 11 (depends on 10) The chain saw according to claim 10, further comprising a protection circuit, wherein the protection circuit is electrically connected to the second control module and is configured to, in response to receiving the second control signal from the second control module, turn off the motor. ### Claim 12 (depends on 11) The chain saw according to claim 11, further comprising a power supply device configured to supply power to the chain saw, wherein the protection circuit comprises a switch circuit, the switch circuit is configured to cut off an electrical connection between the motor and the power supply device, and the switch circuit comprises at least one electronic switch. ### Claim 13 (depends on 12) The chain saw according to claim 12, wherein the protection circuit further comprises a switch control circuit, the switch control circuit is electrically connected to the switch circuit and the second control module, and the switch control circuit is configured to control on-off operations of the switch circuit according to the second control signal from the second control module so as to cut off the electrical connection between the motor and the power supply device. ### Claim 14 (depends on 13) The chain saw according to claim 13, wherein the driving circuit comprises a plurality of driving switches, the switch circuit comprises a first electronic switch, the first electronic switch is electrically connected between control terminals of at least part of the plurality of driving switches and the first control module, the first electronic switch is configured to cut off electrical connections between the first control module and the control terminals of the at least part of the plurality of driving switches, the switch control circuit comprises a second electronic switch, the second electronic switch is electrically connected between a control terminal of the first electronic switch and the second control module, and the second electronic switch is configured to control the on-off operations of the first electronic switch according to the second control signal of the second control module so as to cut off the electrical connections between the first control module and the at least part of the plurality of driving switches, thereby cutting off the electrical connection between the motor and the power supply device. ### Claim 15 (depends on 12) The chain saw according to claim 12, wherein the driving circuit comprises a plurality of driving switches, the switch circuit comprises a third electronic switch, the third electronic switch is electrically connected between control terminals of at least part of the plurality of driving switches and a ground lead, a control terminal of the third electronic switch is electrically connected to the second control module, and the third electronic switch is configured to switch on connections between the at least part of the plurality of driving switches and the ground lead according to the second control signal of the second control module so as to cut off the electrical connection between the motor and the power supply device. ### Claim 16 (depends on 10) The chain saw according to claim 10, wherein the second control module comprises a control circuit and the control circuit comprises at least one switch element or the second control module comprises a microcontroller. ### Claim 17 (depends on 10) The chain saw according to claim 10, further comprising a start switch configured to at least start the chain saw, wherein the start switch is connected to the first control module, and the first control module is configured to, in condition that the first control module detects that the start switch is triggered and receives the second working signal from the second control module, output the first control signal to start the motor. ### Claim 18 (depends on 10) The chain saw according to claim 10, further comprising a brake switch configured to brake the motor, wherein the brake switch is connected to the first control module, and the first control module is configured to, in condition that the first control module detects that the brake switch is triggered and receives the second working signal from the second control module, output the first control signal to the driving circuit so as to brake the motor.