Anti-recoil module and method of controlling operation of power tool

Abstract

An anti-recoil module for a power tool, the anti-recoil module comprising: an accelerometer arranged to detect an acceleration component of the power tool; a power controller configured to control an operating state of the power tool; and a processor configured to determine a recoil state of the power tool based on a change in at least one component of acceleration of the power tool and instruct the power controller to stop operation of the power tool in response to determining the recoil state.

Description

Technical Field

[0001] The present disclosure relates to power tools and, in particular, to controlling power in a manner that mitigates the risk of kickback. Background Art

[0002] Many handheld power tools, such as angle grinders and other tools, include a self-locking feature. Self-locking tools allow the tool to continue operating even when the user releases an input control (e.g., an input trigger). This can be harmful if, for example, the user sets the tool down after use without releasing the self-locking feature. In this case, the tool may continue to operate and potentially cause damage or injury to the user.

[0003] In addition, many tools may experience a so-called "kickback" event, in which the working part of the power tool (e.g., a drill bit or saw blade) becomes lodged in the workpiece and stops suddenly. Kickback may be caused by a knot or foreign object in the workpiece. The sudden stop of the working part may result in a sudden transfer of high torque to the body of the power tool and the user. In many cases, kickback may cause the user to inadvertently release the power tool. This may result in damage or injury to the working part or rotating body of the tool or the tool itself.

[0004] The present disclosure aims to solve or at least partially ameliorate some of the above-mentioned problems with current approaches. Summary of the Invention

[0005] The features and advantages of the present disclosure will be set forth in the following description and, in part, will become apparent from the description, or may be learned by practicing the principles disclosed herein. The features and advantages of the present disclosure may be realized and obtained by the instruments and combinations particularly pointed out in the appended claims.

[0006] According to a first aspect of the present disclosure, an anti-recoil module for a power tool is provided, the anti-recoil module comprising: an accelerometer arranged to detect an acceleration component of the power tool; a power controller configured to control an operating state of the power tool; and a processor configured to determine a recoil state of the power tool based on a change in at least one component of the acceleration of the power tool and to instruct the power controller to stop operation of the power tool in response to determining the recoil state.

[0007] Determining the kickback condition may include determining that a change in at least one component of acceleration of the power tool is above a predetermined threshold.

[0008] Determining the kickback condition may include determining that a rate of change of at least one component of acceleration of the power tool is above a predetermined rate threshold.

[0009] Acceleration components can be measured along any three non-parallel axes.

[0010] The processor may be configured to instruct the power controller to actively decelerate the motor of the power tool in response to determining the kickback condition.

[0011] The processor may be configured to instruct the power controller to apply a preselected braking profile to actively decelerate the motor of the power tool.

[0012] The anti-recoil module may include an active braking mechanism.

[0013] The processor may be configured to activate the active braking mechanism in response to determining a kickback condition.

[0014] According to a second aspect of the present disclosure, a power tool including an anti-kickback module is provided.

[0015] According to a second aspect of the present disclosure, there is provided a method for controlling the operation of a power tool, the method comprising: detecting an acceleration component of the power tool using an accelerometer; determining a recoil state of the power tool based on a change in at least one component of the acceleration of the power tool; and instructing a power controller to stop the operation of the power tool in response to determining the recoil state.

[0016] Determining the kickback condition may include determining that a change in at least one component of acceleration of the power tool is above a predetermined threshold.

[0017] Determining the kickback condition may include determining that a rate of change of at least one component of acceleration of the power tool is above a predetermined rate threshold.

[0018] Acceleration components can be measured along any three non-parallel axes.

[0019] The method may include instructing a power controller to actively decelerate a motor of the power tool in response to determining the kickback condition.

[0020] The method may include instructing the power controller to apply a preselected braking profile to actively decelerate a motor of the power tool.

[0021] The method may include activating an active braking mechanism in response to determining a kickback condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to illustrate the manner in which the above and other advantages and features of the present disclosure can be obtained, the principles briefly described above will be described in more detail by reference to specific embodiments of the present disclosure shown in the accompanying drawings. It should be understood that these drawings depict only exemplary embodiments of the present disclosure and are therefore not to be considered as limiting the scope of the present disclosure. The principles of this disclosure will be described and explained in more detail and in more detail through the use of the accompanying drawings.

[0023] Preferred embodiments of the present disclosure will be explained in further detail below by way of examples and with reference to the accompanying drawings, in which:-

[0024] Figure 1 is a schematic diagram of an anti-kickback module for a power tool according to an embodiment.

[0025] Figure 2 is a graph illustrating accelerometer output for an exemplary embodiment.

[0026] Figure 3A and Figure 3B is a schematic diagram of a power tool including the anti-kickback module of any embodiment.

[0027] Figure 4 is a flowchart illustrating a method of controlling the operation of a power tool according to an embodiment. DETAILED DESCRIPTION

[0028] The following detailed description discusses various embodiments of the present disclosure. Although specific embodiments have been discussed, it should be understood that this is for illustrative purposes only. Those skilled in the relevant art will recognize that other components and configurations may be used without departing from the scope of the present disclosure.

[0029] With reference to the accompanying drawings, Figure 1 FIG2 is a schematic diagram of an anti-backlash module 1 for a power tool according to an embodiment of the present invention. The anti-backlash module 1 includes an accelerometer 10 , a power controller 20 , and a processor 30 .

[0030] The accelerometer 10 is configured to detect acceleration components of the power tool. The accelerometer 10 can be configured to detect one to three acceleration components. The acceleration components can be measured along any non-parallel axes. In some examples, the accelerometer 10 can be a three-axis acceleration sensor configured to measure acceleration along three perpendicular axes. In some examples, the accelerometer 10 can be a six-axis acceleration and rotation sensor.

[0031] The power controller 20 is configured to control the operating state of the power tool. The power controller 20 can be configured to activate or deactivate the power tool. The power controller 20 can activate or deactivate the power tool in response to user control (e.g., using a power button or trigger actuator). The power controller 20 can control the power supplied to the motor of the power tool. The power controller 20 can control the power supplied from the battery pack to the motor. In some examples, the power controller 20 can control the motor speed. The power controller 20 can control the motor speed in response to user control (e.g., using a speed control trigger).

[0032] The processor 30 is configured to determine a recoil state of the power tool based on a change in at least one component of the acceleration of the power tool. The processor 30 can be configured to detect an acceleration that indicates the power tool is not in the user's hands. Detecting a hands-off state of the power tool can indicate that the power tool is in a recoil state.

[0033] The processor 30 is configured to instruct the power controller 20 to cease operation of the power tool in response to determining the kickback condition.

[0034] In this way, if the tool is detected to be out of the hand while it is in operation, the anti-kickback module 1 can trigger anti-kickback protection. This anti-kickback protection can stop the operation of the power tool, thereby reducing the risk of injury caused by a kickback condition of the power tool. By automatically stopping the operation of the power tool, the speed of the power tool can be reduced or stopped faster than the user can deactivate the tool, and often before the user is aware that kickback has occurred.

[0035] In this way, the anti-kickback module 1 can increase the operational safety of the power tool. The anti-kickback module 1 can reduce the potential injury caused by a dangerous kickback event. In addition, the anti-kickback module 1 can reduce the potential injury caused by any release of the tool during operation (for example, putting the tool down when it is locked).

[0036] Determining the kickback condition may include determining that a change in at least one component of acceleration of the power tool is above a predetermined threshold.

[0037] Figure 2 is a graph showing the accelerometer output for an exemplary embodiment. At time T0, the power tool may be in a normal state, for example, the power tool is in normal use or at rest. At T0, the accelerometer 10 may output a stable acceleration with little variation.

[0038] In some examples, the processor 30 can be configured to detect when the power tool is in a stable state. The processor 30 can detect that the acceleration is constant or substantially constant within a threshold value over a predetermined time period. For example, the processor 30 can detect that the acceleration has not varied by more than, for example, 5% or 10% over a predetermined time period. The predetermined time period can be between 0.1 seconds and 1 second. When a stable state is detected, the processor 30 can calibrate set parameters for a normal state. The set parameters can include baseline acceleration values ​​for one or more of the acceleration components.

[0039] At time T1, the power tool may experience a kickback event. For example, a working component of the tool may come into contact with a foreign object in the workpiece and suddenly stop rotating.

[0040] Processor 30 may be configured to detect acceleration changes between 1G and 4G. Acceleration changes may be detected for one or more acceleration components. Acceleration changes may be measured relative to a steady-state baseline acceleration value. The acceleration change may be a threshold acceleration change occurring within a predetermined time window. For example, the predetermined time window may be from 50ms to 500ms. More specifically, the predetermined time window may be 200ms.

[0041] Determining the recoil condition may include determining that a rate of change of at least one component of the power tool's acceleration exceeds a predetermined rate threshold. The predetermined rate threshold may be between 2 G / s and 80 G / s. The processor 30 may be configured to detect when a component of the power tool's acceleration exceeds the predetermined rate threshold within a predetermined time period. For example, the predetermined time period may be between 0.1 s and 1 s.

[0042] The processor 30 can be configured to instruct the power controller 20 to actively decelerate the motor of the power tool in response to determining the kickback condition. For example, if the motor is a brushless motor, the power controller 20 can be configured to transmit a signal that is asynchronous with the rotation of the motor and causes the magnetic element of the motor to act in opposition to the movement of the motor, thereby decelerating the motor. In some examples, the signal transmitted to the motor can be selected from a plurality of signals corresponding to different braking curves (e.g., to cause faster or slower braking of the power tool).

[0043] The processor 30 can be configured to instruct the power controller 20 to apply a preselected braking curve to actively decelerate the power tool's motor. For example, where the power tool is configured to employ a certain braking curve during normal use (e.g., upon releasing the power tool trigger), the power controller 20 can be configured to select a faster curve in response to determining a kickback condition. In this way, the power tool can brake more quickly in an emergency. In some examples, a specific braking curve can also be selected based on a 3-axis sensor; for example, a faster braking curve can be selected if a particularly dangerous motion is detected.

[0044] The anti-backlash module 1 may include an active braking mechanism. The processor 30 may be configured to activate the active braking mechanism in response to determining a backlash state. In some examples, the active braking mechanism may include a friction component, which, for example, includes one or more brake pads, which are arranged to contact a moving part of the power tool (e.g., a disc of an angle grinder). In some examples, the active braking mechanism may include a blocking component, such as an element that physically obstructs the moving part of the power tool. In some examples, the active braking mechanism may be designed to be used once, for example, due to damage to the power tool or the active braking mechanism itself, or may be used multiple times.

[0045] The anti-kickback module 1 can be configured to provide additional protection, such as stopping the operation of the power tool in the event of a drop or fall. The processor 30 can be configured to identify an acceleration profile of a dropped tool, such as a period of free fall followed by an impact. The free fall period can be identified by acceleration values ​​at or near zero. An impact can be identified by a sudden change in acceleration from a value near zero.

[0046] The supply voltage of the accelerometer 10 may be in the range of 1.5V to 5V, and more specifically in the range of 1.62V to 3.6V.

[0047] In some examples, the accelerometer 10 can operate within a range of, for example, ±2g, ±4g, ±8g, or ±16g. In some examples, the range can be user-selectable to configure the fall detection module 10. In some examples, the resolution of the accelerometer 10 can be 14 bits, or any suitable value selected, for example, within a range of 8 bits to 32 bits. In some examples, the data output rate of the accelerometer 10 can be within a range of 1 Hz to 1000 Hz.

[0048] In some examples, the accelerometer 10 can be placed as far away from the motor as possible. This reduces the impact of vibrations from the power tool itself on the accelerometer 10. In some examples, the accelerometer 10 can be placed at the base of the power tool, such as where the power tool connects to the battery pack. The accelerometer 10 can be implemented in a package measuring 2 x 2 x 0.9 mm.

[0049] In some embodiments, the recoil module may be provided as part of the power tool. Alternatively, in some embodiments, the recoil module may be provided separately.

[0050] The individual modules may be connected to the control logic board of the tool, for example via an available bus connection. Alternatively, the modules may be configured to interface with a battery pack or battery connection so as to interrupt the power supply in the event of a backflush condition.

[0051] Figure 3A and Figure 3B is a schematic diagram of a power tool including the anti-kickback module 1 according to any embodiment.

[0052] Figure 3A 1 is a schematic diagram showing an electric power tool 100 according to an embodiment. The power tool is a handheld chain saw, which includes a saw blade and a chain as a working part 110, a motor 120, and an anti-kickback module 1, substantially as described above.

[0053] Figure 3B2 is a schematic diagram showing an electric power tool 200 according to an embodiment. The power tool is a handheld power drill, which includes a chuck as a working part 210, a motor 220, and an anti-backlash module 1, substantially as described above.

[0054] Apart from Figure 3A and Figure 3B In addition to the examples shown in , the power tool may be embodied as, for example, a circular saw, a reciprocating saw, a jigsaw, a hedge trimmer, a rope mower, a lawn mower, or any other suitable tool.

[0055] Figure 4 is a flow chart showing a method of controlling the operation of a power tool according to an embodiment. The method starts at step S01.

[0056] In step S02 , an accelerometer is used to detect the acceleration component of the power tool.

[0057] At step S03 , a kickback state of the power tool is determined based on a change in at least one component of acceleration of the power tool.

[0058] At step S04 , in response to determining the kickback state, the power controller is instructed to stop the operation of the power tool.

[0059] The method ends at step S05.

[0060] The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the present disclosure as defined in the appended claims.

[0061] For clarity of explanation, in some cases, the technology may be presented as including separate functional blocks including functional blocks comprising devices, device components, steps in methods or routines embodied in software or a combination of hardware and software.

[0062] The method according to the above example can be realized using a computer executable instruction stored in a computer readable medium or that can otherwise be obtained from a computer readable medium. Such instructions can include, for example, causing or otherwise configuring a general-purpose computer, a special-purpose computer or a special-purpose processing device to perform instructions and data of a certain function or functional group. The part of the computer resource used can be accessed through a network. Computer executable instructions can be, for example, binary instructions, intermediate format instructions (such as, assembly language), firmware, or source code. The example of a computer readable medium that can be used to store instructions during the method according to the described example, the information used, and / or the information generated includes a disk or optical disk, a flash memory, a universal serial bus (USB) device provided with a non-volatile memory, a network storage device, etc.

[0063] Devices implementing the methods according to these disclosures may include hardware, firmware, and / or software and may take any of a variety of form factors. Typical examples of such form factors include laptop computers, smartphones, small form factor personal computers, personal digital assistants, and the like. The functionality described herein may also be embodied in peripheral devices or add-in cards. By way of further example, such functionality may also be implemented on a circuit board between different chips or different processes executed in a single device.

[0064] Instructions, the media for transmitting such instructions, computing resources for executing these instructions, and other structures for supporting these computing resources are all means for providing the functionality described in this disclosure.

[0065] Although various examples and other information are used to explain aspects within the scope of the appended claims, in such examples, no limitation to the claims should be implied based on specific features or arrangements, as a person of ordinary skill will be able to use these examples to derive a variety of implementations. Further, although some subject matter may have been described in language specific to examples of structural features and / or method steps, it should be understood that the subject matter defined in the appended claims is not necessarily limited to these features or actions described. For example, such functionality may be distributed differently or performed in components other than those identified herein. Instead, the described features and steps are disclosed as examples of components of systems and methods within the scope of the appended claims.

Claims

1. An anti-recoil module for a power tool, the anti-recoil module comprising: an accelerometer arranged to detect an acceleration component of the power tool; a power controller configured to control an operating state of the power tool; as well as a processor configured to: determining a kickback state of the power tool based on a change in at least one component of acceleration of the power tool, and In response to determining the kickback condition, the power controller is instructed to cease operation of the power tool.

2. The anti-recoil module according to claim 1, wherein: Determining the kickback condition includes determining that a change in at least one component of acceleration of the power tool is above a predetermined threshold.

3. The anti-recoil module according to claim 1, wherein: Determining the kickback condition includes determining that a rate of change of at least one component of acceleration of the power tool is above a predetermined rate threshold.

4. An anti-recoil module according to any preceding claim, wherein: The acceleration components are measured along any three non-parallel axes.

5. An anti-recoil module according to any preceding claim, wherein: The processor is further configured to instruct the power controller to actively decelerate a motor of the power tool in response to determining the kickback condition.

6. The anti-recoil module according to claim 5, wherein: The processor is configured to instruct the power controller to apply a preselected braking profile to actively decelerate a motor of the power tool.

7. The anti-recoil module of any preceding claim, further comprising an active braking mechanism, wherein: The processor is further configured to activate the active braking mechanism in response to determining the kickback condition.

8. A power tool comprising an anti-kickback module according to any preceding claim.

9. A method of controlling the operation of a power tool, the method comprising: Using an accelerometer to detect an acceleration component of the power tool; determining a kickback condition of the power tool based on a change in at least one component of acceleration of the power tool, and A power controller is instructed to cease operation of the power tool in response to determining the kickback condition.

10. The method of claim 9, wherein: Determining the kickback condition includes determining that a change in at least one component of acceleration of the power tool is above a predetermined threshold.

11. The method of claim 9, wherein: Determining the kickback condition includes determining that a rate of change of at least one component of acceleration of the power tool is above a predetermined rate threshold.

12. The method according to any one of claims 9 to 11, wherein The acceleration components are measured along any three non-parallel axes.

13. The method of any one of claims 9 to 12, further comprising instructing the power controller to actively decelerate a motor of the power tool in response to determining the kickback condition.

14. The method of claim 13, comprising instructing the power controller to apply a preselected braking profile to actively decelerate the motor of the power tool.

15. The method of any one of claims 9 to 14, further comprising activating an active braking mechanism in response to determining the kickback condition.

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