Power tool with safety brake including impulse solenoid and method of operating the power tool

Abstract

A power tool and method of operating the power tool have a safety brake including an impulse solenoid. The power tool includes an implement holder for holding an implement configured to perform an operation on a workpiece. The power tool also includes a motor for actuating the implement holder to move the implement, and a safety brake. The safety brake includes a brake assembly configured to transition between a disengaged configuration in which the brake assembly permits movement of the implement and an engaged configuration in which the brake assembly resists movement of the implement. The safety brake also includes an actuator assembly configured to selectively provide a driving force to transition the brake assembly from the disengaged configuration to the engaged configuration. The actuator assembly includes an impulse solenoid and a solenoid drive circuit.

Description

[Technical Field]

[0001] (Related applications) This application claims priority to U.S. Provisional Patent Application No. 63 / 114,819, filed November 17, 2020, the entire disclosure of which is incorporated herein by reference. (Field of invention)

[0002] This disclosure generally relates to power tools having a safety brake including an impulse solenoid, and a method for operating the power tool. [Background technology]

[0003] Power tools use an instrument to work on a workpiece. The instrument can be sharp and, in some cases, pose a safety hazard to the power tool user. Power tools often include guards and / or other mechanisms to prevent the user from coming into contact with the instrument. However, it is sometimes even more desirable to have secondary and / or additional safety mechanisms. Some such secondary and / or additional safety mechanisms have been developed, but generally they are one-time safety mechanisms or require high voltage to operate. It is sometimes desirable to implement multi-use and / or low-voltage safety mechanisms. Therefore, there is a need for improved actuator assemblies for braking power tools, brake assemblies including actuator assemblies, and power tools including brake assemblies. [Overview of the project] [Means for solving the problem]

[0004] A power tool having a safety brake including an impulse solenoid and a method for operating the power tool. The power tool includes an instrument holder for holding an instrument configured to perform work on a workpiece. The power tool also includes a motor that actsuates the instrument holder to move the instrument, and a safety brake. The safety brake includes a brake assembly configured to transition between a disengaged configuration that allows movement of the instrument and an engaged configuration that resists movement of the instrument. The safety brake also includes an actuator assembly configured to selectively provide a driving force to transition the brake assembly from the disengaged configuration to the engaged configuration. The actuator assembly includes an impulse solenoid and a solenoid drive circuit. The impulse solenoid is configured to selectively transition from a non-operated state to an operated state in response to the reception of an electrical impulse, and to provide a driving force during the transition from the non-operated state to the operated state. The solenoid drive circuit is configured to selectively generate an electrical impulse signal. The electrical impulse signal has an impulse voltage of up to 43 volts (V) and an impulse duration of up to 10 milliseconds (ms), and is configured to transition the impulse solenoid from a non-operating state to an operating state with a transition time of up to 15 milliseconds.

[0005] This method includes applying an electric current to the motor of a power tool and moving the tool's implement in response to the application. The method also includes detecting operating parameters that indicate undesirable events to be avoided by the power tool during operation. The method further includes transitioning the power tool's safety brake from a disengaged configuration, where the safety brake allows the tool's movement, to an engaged configuration, where the safety brake resists the tool's movement. The safety brake includes an actuator assembly configured to selectively provide the driving force for the transition. The actuator assembly includes an impulse solenoid and a solenoid drive circuit. The impulse solenoid is configured to selectively transition from a disengaged to an engaged state in response to the reception of an electric impulse and to provide the driving force during the transition from the disengaged to the engaged state. The solenoid drive circuit is configured to selectively generate an electric impulse signal in response to the detection of operating parameters, and the transition includes providing the electric impulse signal to the impulse solenoid to transition the impulse solenoid from a disengaged to an engaged state, thereby transitioning the brake assembly from a disengaged configuration to an engaged configuration. The electrical impulse signal has a maximum impulse voltage of 43 volts and a maximum impulse duration of 10 milliseconds, and is configured to cause the impulse solenoid to transition from a non-operating state to an operating state with a maximum transition time of 15 milliseconds. [Brief explanation of the drawing]

[0006] [Figure 1] This figure schematically shows an example of an actuator assembly usable in a brake assembly and / or power tool according to the present disclosure, and shows the actuator assembly in a non-operating state. [Figure 2] Figure 1 is a schematic diagram showing the operating state of the actuator. [Figure 3] This is a slightly more detailed diagram of an embodiment of an actuator assembly usable with a brake assembly and / or power tool according to the present disclosure, showing the actuator assembly in a non-operating state. [Figure 4] This figure shows the magnetomotive force that can be generated by the impulse solenoid according to this disclosure. [Figure 5] This is a more detailed diagram showing an example of a solenoid drive circuit that forms part of the actuator according to this disclosure. [Figure 6] A schematic diagram of an example of a power tool that may include an actuator assembly according to this disclosure. [Figure 7] This is a more detailed schematic diagram of an example of a power tool that may include an actuator assembly according to the present disclosure, showing the actuator assembly in a non-operating state. [Figure 8] This is a more detailed schematic diagram of an example of a power tool that may include an actuator assembly according to this disclosure, showing the actuator assembly in an operating state. [Figure 9] This figure shows another example of a power tool that may include an actuator assembly according to the present disclosure, in which the actuator assembly is in a non-operating state. [Figure 10] Figure 9 shows the actuator assembly of a power tool in an intermediate state. [Figure 11] Figures 9-10 show the actuator assembly of a power tool in an operating state. [Figure 12] This is a schematic diagram of yet another example of a power tool which may include an actuator assembly according to the present disclosure. [Figure 13] This flowchart shows an example of how to operate a power tool according to this disclosure. [Modes for carrying out the invention]

[0007] Figures 1 to 13 show examples of actuator assemblies 160, brake assemblies 120 including actuator assemblies, and power tools and / or methods 500 including brake assemblies, according to the present disclosure. In each of Figures 1 to 13, elements serving similar or at least substantially similar purposes are given the same numbering. These elements may not be described in detail herein with respect to each of Figures 1 to 13. Similarly, not all elements may be numbered in each of Figures 1 to 13, but reference numbers for them may be consistently available herein. Elements, components and / or features discussed herein with respect to one or more of Figures 1 to 13 may be included in and / or utilized in any of Figures 1 to 13 without departing from the scope of the present disclosure.

[0008] Generally, elements that may be included in a particular embodiment are shown with solid lines, and optional elements are shown with dashed lines. However, elements shown with solid lines are not essential to all embodiments and may be omitted in some embodiments without departing from the scope of this disclosure.

[0009] Figure 1 is a schematic diagram of an example of an actuator assembly 160 available for use with a safety brake 100 and / or power tool 8 according to the present disclosure, showing the actuator assembly in a non-operating state 302. Figure 2 is a schematic diagram showing the actuator assembly 160 of Figure 1 in an operating state 304. Figure 3 is a more detailed diagram of an embodiment of the actuator assembly 160 available for use with a brake assembly 120 and / or power tool 8 according to the present disclosure, showing the actuator assembly in a non-operating state 302.

[0010] As shown in FIGS. 1-3, the actuator assembly 160 includes an impulse solenoid 300 and a solenoid drive circuit 360. The impulse solenoid 300 is configured to selectively transition from an inactive state 302, as shown in FIGS. 1 and 3, to an active state 304, as shown in FIG. 2, in response to receiving an electrical impulse signal 362. As schematically shown in FIG. 2, the impulse solenoid 300 is also configured to provide a driving force 168 for the operation of the brake assembly 120 during and / or in response to the transition from the inactive state 302 to the active state 304.

[0011] The solenoid drive circuit 360 is configured to selectively generate an electrical impulse signal. The electrical impulse signal has an impulse voltage and an impulse duration. The impulse voltage and the impulse duration are sufficient to transition the impulse solenoid from the inactive state to the active state within a threshold transition time. Examples of the impulse voltage include at least 10 volts (V), at least 15V, at least 20V, at least 25V, at least 30V, at least 35V, at least 40V, up to 42V, up to 41V, up to 40V, up to 38V, up to 36V, up to 34V, up to 32V, and / or up to 30V. More specific examples of the impulse voltage include an impulse voltage equal to 42.4V, at least substantially equal to 42.4V, and / or up to 42.4V. The impulse voltages within these ranges reduce the likelihood of an electrical shock to the user and / or are readily obtainable with battery-powered power tools operating at a typical battery voltage. Additionally or alternatively, the impulse voltages within these ranges are low enough to enable the construction of the power tool 8 without the additional electrical insulation required for higher impulse voltages, thereby reducing the cost, complexity, and / or weight of the power tool 8.

[0012] Examples of the impulse duration include an impulse duration of at least 0.25 milliseconds (ms), at least 0.5 ms, at least 0.75 ms, at least 1.0 ms, at least 1.5 ms, at least 2.0 ms, at least 2.5 ms, at least 3.0 ms, at least 3.5 ms, at least 4.0 ms, at least 4.5 ms, at least 5.0 ms, at least 5.5 ms, at least 6.0 ms, at least 6.5 ms, at least 7.0 ms, at least 7.5 ms, at least 8.0 ms, up to 9 ms, up to 8.5 ms, up to 8.0 ms, up to 7.5 ms, up to 7.0 ms, up to 6.5 ms, up to 6.0 ms, up to 5.5 ms, up to 5.0 ms, up to 4.5 ms, up to 4.0 ms, up to 3.5 ms, up to 3.0 ms, up to 2.5 ms and / or up to 2.0 ms. The impulse durations within these ranges may be sufficient to transition the impulse solenoid from the non-operating state 302 to the operating state 304 without overheating the impulse solenoid.

[0013] Examples of the threshold transition time include a transition time of at least 1 ms, at least 2 ms, at least 4 ms, at least 6 ms, at least 8 ms, at least 10 ms, up to 30 ms, up to 25 ms, up to 20 ms, up to 19 ms, up to 18 ms, up to 17 ms, up to 16 ms, up to 15 ms, up to 14 ms, up to 13 ms, up to 12 ms, up to 11 ms and / or up to 10 ms. These transition times are small enough so that in case the tool contacts a user, it may be possible for the power tool to stop the tool before inflicting damage and / or injury or before inflicting significant damage and / or injury.

[0014] As will be described in more detail herein and as shown in Figures 1 and 2, the power tool 8 may include a tool 40 configured to perform work on a workpiece. Also as will be described in more detail herein, the tool 40 may move, may be sharp, and / or the power tool may pose a potential safety hazard to the user, such as when the user comes into contact with the tool while it is in operation. In consideration of this, the actuator assembly 160 may be configured to selectively and operationally engage the brake assembly 120 of the safety brake 100 to stop the tool or stop the movement of the tool. In some embodiments, this may involve selectively and operationally engaging or contacting the brake assembly with the tool 40. This may protect the user of the power tool from unsafe conditions detectable by the power tool, as exemplified by the transition from a non-operating state 302 shown in Figures 1 and 3 to an operating state 304 shown in Figure 2.

[0015] In some examples of the power tool 8 including the actuator assembly 160, the actuator assembly may be configured to generate, initiate, and / or initiate a chain reaction in the brake assembly 120 and / or within the brake assembly. In other words, the actuator assembly 160 may be configured to initiate movement in the brake assembly 120, together with another component of the power tool, which also provides part of the driving force used to stop the operation of the tool. As an example, the brake assembly 120 may include a brake assembly biasing mechanism, such as a spring, which can be released by the actuator assembly 160. Thus, a driving force is provided that uses the brake assembly biasing mechanism to stop the operation of the tool. In an additional example, the brake assembly 120 may include a preload and / or pretension assembly, such as a lever and / or clutch, which can be released by the actuator assembly 160. Thus, a driving force is provided that uses the pretension assembly to enable the stopping of the operation of the tool.

[0016] In specific examples, as will be described in more detail herein, the brake assembly 120 may include a brake cam 130 that is operationally engageable with the fixture 40. In some such examples, an actuator assembly 160 is used to drive or move the brake cam into contact with the fixture, so that the movement of the fixture provides the driving force for an additional engagement between the fixture and the cam, which in turn resists and / or stops further movement of the fixture.

[0017] The impulse solenoid 300 can be configured to generate a magnetomotive force in response to the reception of an electrical impulse signal 362, which can generate, create, be proportional to, and / or become the driving force 168 schematically shown in Figure 2. In other words, the magnetomotive force can cause the impulse solenoid to transition from the non-operating state 302 in Figures 1 and 3 to the operating state 304 in Figure 2. Examples of magnetomotive forces include those of at least 5,000 ampere-turns (At or Aw), at least 6,000 At, at least 7,000 At, at least 7,500 At, at least 10,000 At, at least 12,500 At, at most 20,000 At, at most 19,000 At, at most 18,000 At, at most 17,000 At, at most 16,000 At, at most 15,000 At, at most 14,000 At, at most 13,000 At, at most 12,000 At, at most 11,000 At, and / or at most 10,000 At. Magnetomotive forces within this range may be sufficient for the impulse coil to reliably operate the brake assembly 120.

[0018] The impulse solenoid 300 may include any suitable structure that can be adapted, configured, designed and / or constructed to selectively transition from a non-operating state 302 in Figures 1 and 3 to an operating state 304 in Figure 2 in response to the reception of an electrical impulse signal. Additionally or alternatively, the impulse solenoid 300 may include any suitable structure that can be adapted, configured, designed and / or constructed to operate on the impulse voltage applied to the brake assembly 120 by applying a driving force 168, or selectively applied, and to receive the impulse voltage for the duration of the impulse and / or to transition from a non-operating state to an operating state during a threshold transition time.

[0019] As an example, the impulse solenoid 300 may include an impulse coil 310, as shown by dashed lines in Figures 1 and 2 and by solid lines in Figure 3. The impulse coil 310 may be configured to receive an electrical impulse signal 362, if present, to generate a magnetomotive force and / or a magnetic field in response to the electrical impulse signal. In some examples, the impulse coil 310 may include a winding 312. The winding 312 may also be referred to as a multiple wire wrap. At least the region of the winding 312 may include a helical-wound wire and / or a helical-wound region. Examples of the winding 312 include conductive wire, metal wire, aluminum wire and / or copper wire.

[0020] As another example, the impulse solenoid 300 may include a solenoid armature 320. The solenoid armature 320 may be referred to herein as the actuator arm 164 of the actuator assembly 160, and / or the actuator arm 164 of the actuator assembly 160, or operably mounted thereto. The actuator arm 164 can operably connect the actuator assembly 160 to the brake assembly 120.

[0021] The solenoid armature 320 can be configured to operably transition between a non-operating position 322 shown in Figures 1 and 3 and an operating position 324 shown in Figure 2 when the impulse solenoid transitions between a non-operating state 302 and an operating state 304. The solenoid armature 320 can have and / or define an elongated axis 328 and be configured to linearly translate along the elongated axis when the impulse solenoid transitions between a non-operating state and an operating state. The elongated axis 328 may also be referred to herein as the operating axis 166 of the actuator assembly 160. As shown in Figures 1 and 2, the solenoid armature 320 can be configured to operably engage with the brake assembly 120 or to engage with the brake assembly 120 to selectively apply the driving force 168 to the brake assembly. Alternatively, the solenoid armature 320 may be configured to receive a magnetomotive force from the impulse coil 310 and selectively apply a driving force 168 to the brake assembly in response to the reception of that magnetomotive force.

[0022] The solenoid armature 320 may include any suitable components and / or combinations of components. For example, as shown by dashed lines in Figures 1 and 2 and by solid lines in Figure 3, the solenoid armature 320 may include a pin 332 and an anchor 334 operably attached to the pin. The anchor 334, if present, has an anchor diameter larger than the pin diameter of the pin 332, thereby enabling and / or promoting improved alignment of the solenoid armature 320 within the impulse solenoid 300, reducing wear due to the solenoid armature's movement within the impulse solenoid, and / or increasing the product life of the impulse solenoid. The pin 332 may include or be defined a rounded, partially spherical and / or hemispherical pin end 336, which can be configured to engage, operably engage and / or directly engage with the brake assembly 120 in Figures 1 and 2.

[0023] In some examples, as shown by dashed lines in Figures 1 and 2 and by solid lines in Figure 3, the impulse solenoid 300 may include a cap 330, which is also referred to herein as a dust cap 330. The cap 330 may be configured to reduce the possibility of foreign matter and / or dust entering the interior of the impulse solenoid when it is present. In some examples, as shown by dashed lines in Figure 2, the cap 330 may form part of the solenoid armature 320 and / or be configured to move with the solenoid armature. In other examples, as shown by dashed lines in Figures 1 and 2 and by solid lines in Figure 3, the cap 330 may include a central hole 331 through which the solenoid armature moves and / or operates.

[0024] The solenoid armature 320 can have and / or be specified to any suitable dimensions. For example, the solenoid armature 320 can specify the length of the armature, or the total length of the armature 321 as shown in Figure 1. Examples of lengths 321 include at least 25 millimeters (mm), at least 30 mm, at least 35 mm, at least 40 mm, at least 45 mm, at least 50 mm, at most 70 mm, at most 65 mm, at most 60 mm, at most 55 mm, at most 50 mm, at most 45 mm, and / or at most 40 mm.

[0025] In another example, pin 332 may also specify a pin diameter 333, if present, as shown in Figure 1. Examples of pin diameters 333 include at least 2 mm, at least 2.5 mm, at least 3 mm, at least 3.5 mm, at least 4 mm, at least 4.5 mm, at least 5 mm, at most 7 mm, at most 6.5 mm, at most 6 mm, at most 5.5 mm, at most 5 mm, at most 4.5 mm, at most 4 mm, at most 3.5 mm and / or at most 3 mm.

[0026] As yet another example, anchor 334 may define anchor diameter 335, if present, as also shown in Figure 1. Examples of anchor diameter 335 include at least 10 mm, at least 10.5 mm, at least 11 mm, at least 11.5 mm, at least 12 mm, at least 12.5 mm, at least 13 mm, at least 13.5 mm, at least 14 mm, at most 17 mm, at most 16.5 mm, at most 16 mm, at most 15.5 mm, at most 15 mm, at most 14.5 mm, at most 14 mm, at most 13.5 mm, at most 13 mm, at most 12.5 mm and / or at most 12 mm.

[0027] The solenoid armature 320 may be relatively small and / or have a relatively small armature mass. Such a small armature mass can reduce the transition time from the non-operating position 322 to the operating position 324 and / or enable and / or accelerate the transition of the impulse solenoid 300 from the non-operating state 302 to the operating state 304 within a threshold transition time. In other words, a smaller armature mass makes it possible to make the transition of the impulse solenoid 300 from the non-operating state 302 to the operating state 304 faster than with conventional solenoids containing larger and more massive armatures. Examples of armature masses include at least 1 gram (g), at least 2 g, at least 3 g, at least 4 g, at least 5 g, at least 6 g, at least 7 g, at least 8 g, at least 9 g, at least 10 g, at least 12 g, at least 14 g, at least 16 g, at least 18 g, at least 20 g, at least 25 g, at most 40 g, at most 38 g, at most 36 g, at most 34 g, at most 32 g, at most 30 g, at most 28 g, at most 26 g, at most 24 g, at most 22 g, at most 20 g, at most 18 g, at most 16 g, at most 14 g, at most 12 g, at most 10 g and / or at most 8 g. The relatively small mass of these armatures reduces the inertia of the solenoid armature 320, enabling rapid acceleration of the solenoid armature and / or facilitating the transition of the brake assembly 120 from the disengaged configuration 140 to the engaged configuration 142 within a threshold transition time and / or accelerating it.

[0028] As shown in the transition from the non-operating state 302 in Figure 1 to the operating state 304 in Figure 2, and as shown in Figure 2, the solenoid armature 320 has and / or defines an armature range of motion 326. The armature range of motion 326 can be defined as the amount of movement between the non-operating position 322 in Figure 1 and the operating position 324 in Figure 2, and the armature range of motion 326 can have any appropriate value and / or magnitude. Examples of armature range of motion 326 include distances of at least 0.5 mm, at least 1.0 mm, at least 1.5 mm, at least 2.0 mm, at least 2.5 mm, at least 3 mm, at least 3.5 mm, at least 4.0 mm, at most 10 mm, at most 9.0 mm, at most 8.0 mm, at most 7.0 mm, at most 6.0 mm, at most 5.5 mm, at most 5.0 mm, at most 4.5 mm, at most 4.0 mm, at most 3.5 mm, at most 3.0 mm, at most 2.5 mm and / or at most 2.0 mm. These armature ranges of motion may be sufficient for the impulse solenoid 300 to transition the brake assembly 120 from the disengaged configuration 140 to the engaged configuration 142 within a threshold transition time.

[0029] As shown by dashed lines in Figures 1 and 2, and by solid lines in Figure 3, the impulse solenoid 300 may include a biasing mechanism 340. The biasing mechanism 340, if present, may be configured to bias or prompt the impulse solenoid 300 toward a non-operating state 302. Additional or alternative, for example, following the reception of an electrical impulse signal 362 by the impulse solenoid, following the application of the electrical impulse signal for the duration of the impulse, and / or after, or in response to, the cessation of the supply of the electrical impulse signal to the impulse solenoid. Additional or alternative, the biasing mechanism 340 may be configured to prompt the solenoid armature 320 toward a non-operating position 322. Examples of the biasing mechanism 340 include elastic members, springs, and / or coil springs.

[0030] In some embodiments, the impulse solenoid 300 may include a brake assembly biasing mechanism base 350, as shown by dashed lines in Figures 1 and 2 and by solid lines in Figure 3. The brake assembly biasing mechanism base 350, if present, is adapted and configured to be operably mounted to the brake assembly biasing mechanism 144, and can have such dimensions, shape and / or structure. As will be described in more detail herein, the brake assembly biasing mechanism 144 may be configured to drive the brake assembly 120 toward the impulse solenoid 300 and / or in the opposite direction to the driving force 168. In other words, when the impulse solenoid 300 does not apply the driving force 168, the brake assembly biasing mechanism 144 may drive the brake assembly toward a corresponding disengagement configuration 140, in which the brake assembly does not engage with the fixture 40, as shown in Figure 1.

[0031] The impulse solenoid 300 may have and / or be defined any structure suitable for transitioning between a non-operating state 302 and an operating state 304 upon receiving an electrical impulse signal 362 and / or within a threshold transition time. However, a specific structure for the impulse solenoid 300 may be advantageous and / or provide improved performance compared to other structures. With this in mind, Figure 4 shows the magnetomotive force that can be generated by the impulse solenoid according to the present disclosure. More specifically, Figure 4 is an example of a parametric analysis in which the magnetomotive force generated by the impulse coil 310 of the impulse solenoid is shown on the vertical axis for various numbers of turns of the winding 312 as shown on the horizontal axis. Figure 4 further shows the effect of the winding diameter, shown by the horizontal line in Figure 4, on the magnetomotive force. More specifically, Figure 4 shows the magnetomotive force for winding diameters between 0.1 mm and 1.5 mm.

[0032] In the example in Figure 4, the impulse voltage is assumed to be 42.4 volts. Furthermore, the peak impulse current is assumed to be 820 amperes, the maximum time constant for the impulse coil is assumed to be 0.39 ms, the maximum wire diameter of the winding is assumed to be 1.5 millimeters (mm), and the maximum inductance of the impulse coil is assumed to be 0.407 millihenries. As will be discussed in more detail herein, a parametric analysis as shown in Figure 4 can be used to determine and / or establish one or more characteristics of the impulse solenoid 300.

[0033] In Figure 4, the black operating boundary indicated by 410 separates various regions of the parametric analysis. More specifically, the winding 312 in the region to the left of the operating boundary 410, indicated by 412, may generate unacceptably high peak currents within the winding when it receives an electrical impulse, and / or the impulse current of the electrical impulse signal may require an unacceptably high current for the impulse solenoid to generate the desired magnetomotive force.

[0034] The winding 312 in the region to the right of the operating boundary 410, indicated by 414, has an unacceptably large time constant, which can result in an unacceptably large or long transition time for the impulse solenoid. In other words, the winding in the region 414 to the right of the line may make it impossible for the impulse solenoid to transition from a non-operating state to an operating state within a threshold transition time.

[0035] The winding 312 in the region to the right of the operating boundary 410 indicated by 416 may have an undesirably large number of turns. This may increase the overall mass of the impulse solenoid and / or make it difficult to apply the desired magnetomotive force to the impulse solenoid while maintaining the impulse voltage within the desired range. An example thereof is disclosed herein.

[0036] From the example of parametric analysis in Figure 4, a desired wire diameter and / or number of windings can be selected. Generally, it is desirable to operate near, but not necessarily at, the maximum magnetomotive force that can be generated under given constraints. With this in mind, for the exemplary parametric analysis in Figure 4, an impulse solenoid containing an impulse coil with a wire diameter of approximately 0.6 mm to 1.15 mm and a number of windings of approximately 35 to 75 (e.g., within the region indicated by R) may be useful under the conditions shown in Figure 4. In a specific example, a winding with a diameter of 0.9 mm and 57 turns (as shown by X in Figure 4) is within the operating boundary 410 and can provide a desired magnetomotive force of approximately 12,000 At, while simultaneously avoiding potential instability that may be observed when using a number of turns and wire diameter close to the peak of the magnetomotive force. More generally, and depending on the exact configuration and constraints used, the impulse solenoid 300 can be selected to exhibit one or more of the characteristics discussed below.

[0037] In certain embodiments, the impulse coil 310 and / or its winding 312 may have at least 10 windings, at least 20 windings, at least 30 windings, at least 40 windings, at least 45 windings, at least 50 windings, at least 55 windings, at least 60 windings, at least 65 windings, at least 70 windings, at least 75 windings, or at least 80 windings. Additionally or alternatively, the winding may have at most 120 windings, at most 110 windings, at most 100 windings, at most 90 windings, at most 80 windings, at most 75 windings, at most 70 windings, at most 65 windings, at most 60 windings, at most 55 windings, at most 50 windings, at most 45 windings, at most 40 windings, or at most 30 windings. In some cases, an impulse coil 310 with fewer windings would not be able to provide the desired magnetomotive force, and an impulse coil with more windings would be undesirably large and / or heavy, thus the above range is available.

[0038] In certain embodiments, the impulse coil 310 and / or its winding 312 may have a wire diameter of at least 0.3 mm, at least 0.4 mm, at least 0.5 mm, at least 0.6 mm, at least 0.7 mm, at least 0.8 mm, at least 0.9 mm, at least 1.0 mm, at least 1.1 mm, or at least 1.2 mm. Additionally or alternatively, the winding may have a wire diameter of at most 1.5 mm, at most 1.4 mm, at most 1.3 mm, at most 1.2 mm, at most 1.1 mm, at most 1.0 mm, at most 0.9 mm, at most 0.8 mm, at most 0.7 mm, or at most 0.6 mm. The above ranges are available because, in some examples, an impulse coil 310 with a smaller wire diameter would have an unacceptably high resistance, and an impulse coil with a larger wire diameter would be undesirably large and / or heavy.

[0039] In certain examples, the impulse coil 310 and / or its winding 312 may have a time constant, definable by dividing the inductance of the impulse coil by the resistance of the impulse coil, of at least 0.01 ms, at least 0.05 ms, at least 0.1 ms, at least 0.15 ms, or at least 0.2 ms. Additional examples of time constants include those with a maximum of 0.4 ms, 0.39 ms, 0.38 ms, 0.37 ms, 0.36 ms, 0.35 ms, 0.34 ms, 0.33 ms, 0.32 ms, 0.31 ms, 0.30 ms, 0.28 ms, 0.26 ms, 0.24 ms, 0.22 ms, 0.20 ms, 0.18 ms, 0.16 ms, 0.14 ms, 0.12 ms, or 0.10 ms. A specific example of a time constant is 0.39 ms. Time constants within these ranges allow the impulse coil to transition from a non-operating state 302 to an operating state 304 within the threshold transition time disclosed herein.

[0040] In certain embodiments, the impulse coil may have a coil inductance of at least 0.01 millihenry (mH), at least 0.05 mH, at least 0.1 mH, at least 0.15 mH, or at least 0.2 mH. Additionally or alternatively, the impulse coil may have a maximum coil inductance of at most 0.44 mH, at most 0.42 mH, at most 0.40 mH, at most 0.38 mH, at most 0.36 mH, at most 0.34 mH, at most 0.32 mH, at most 0.30 mH, at most 0.28 mH, at most 0.26 mH, at most 0.24 mH, at most 0.22 mH, at most 0.20 mH, at most 0.18 mH, at most 0.16 mH, or at most 0.14 mH. In a specific example, the impulse coil may have a coil inductance of 0.41 mH. Inductances within these ranges may enable a transition from a non-operating state 302 to an operating state 304 within the threshold transition time disclosed herein and / or enable an impulse coil to generate a magnetomotive force within the range disclosed herein.

[0041] Returning to Figures 1-3, the actuator assembly 160 may include a solenoid drive electrical conduit 390. The solenoid drive electrical conduit 390 may be configured to transmit an electrical impulse signal 362, if present, from the solenoid drive circuit 360 and / or to the impulse solenoid 300. Examples of solenoid drive electrical conduits include metal conductors, metal wires, metal traces, insulated metal wires, metal cables, and insulated metal cables.

[0042] The solenoid drive electrical conduit 390 can be selected and / or sized to repeatedly transmit the impulse current of the electrical impulse signal 362 for at least the impulse duration and / or at the duty cycle of the solenoid drive circuit. This can include transmitting the electrical impulse signal to the solenoid drive conduit without damage and / or below the threshold temperature rise of the solenoid drive circuit. This threshold temperature rise can also be referred to herein as a measurable or measured threshold temperature rise. Examples of the electrical impulse signal and the impulse duration are disclosed herein. Examples of the duty cycle include at least 1×10 -11 at least 1×10 -10 at least 1×10 -9 at least 1×10 -8 at least 1×10 -7 at least 1×10 -6 at least 1×10 -5 at least 1×10 -4 up to and including 1×10 -3 and / or up to and including 1×10 -4 . The duty cycle can be defined as the impulse duration divided by the supply interval of the electrical impulse signal to the impulse coil.

[0043] Examples of threshold temperature rises for solenoid-driven electrical conduits include temperature rises of less than 10°C, less than 20°C, less than 30°C, less than 40°C, less than 50°C, less than 60°C, less than 70°C, less than 80°C, less than 90°C, or less than 100°C. As previously stated, this threshold temperature rise may and / or may be referred to herein as a measurable temperature rise. As used herein, the term “measurable temperature rise” can refer to a temperature rise that persists for at least a threshold period and / or a temperature rise present in at least a threshold volume of the material, such as within the threshold volume of the impulse coil 310 and / or winding 312. Examples of threshold periods include threshold periods of at least 0.1 seconds, at least 0.25 seconds, at least 0.5 seconds, at least 1 second, at least 2.5 seconds, or at least 5 seconds. Examples of threshold volumes for materials include at least 0.1 cubic millimeters, at least 0.25 cubic millimeters, at least 0.5 cubic millimeters, at least 1 cubic millimeter, at least 2.5 cubic millimeters, at least 5 cubic millimeters, or at least 10 cubic millimeters.

[0044] The solenoid drive circuit 360 may include any suitable structure and / or a structure that can be adapted, configured, designed and / or constructed to selectively generate and / or provide an electrical impulse signal. This may include generating and / or providing an electrical impulse signal at a predetermined impulse voltage and / or for a predetermined impulse duration.

[0045] In some embodiments, the solenoid drive circuit may be configured to generate and / or provide an impulse signal with an impulse current. Examples of impulse currents include currents of at least 50 amperes (A), at least 75A, at least 100A, at least 125A, at least 150A, at least 175A, at least 200A, at least 250A, at least 300A, at least 350A, at least 400A, at least 450A, at least 500A, at least 550A, at least 600A, at least 650A, at least 700A, at least 750A, or at least 800A. Examples of additional and / or alternative impulse currents include currents of up to 1000A, 950A, 900A, 850A, 800A, 750A, 700A, 650A, 600A, 550A, 500A, 450A, 400A, 350A, 300A, or 250A. These impulse currents are, It may be insufficient to transition the impulse solenoid from the non-operating position 322 to the operating position 324 within a threshold transition time, to generate a magnetomotive force of the above magnitude, and / or to heat the impulse solenoid when provided by the above duty cycle.

[0046] In some embodiments, the solenoid drive circuit may be configured to generate and / or provide an impulse signal at a current rise rate. Examples of current rise rates include rise rates of at least 20,000 amperes per second (A / s), at least 25,000 A / s, at least 30,000 A / s, at least 35,000 A / s, at least 40,000 A / s, at least 45,000 A / s, at least 50,000 A / s, at least 55,000 A / s, at least 60,000 A / s, at least 70,000 A / s, at least 80,000 A / s, at least 90,000 A / s, at least 100,000 A / s, at least 200,000 A / s, at least 300,000 A / s, at least 400,000 A / s, at least 500,000 A / s, at least 600,000 A / s, at least 700,000 A / s, or at least 800,000 A / s. Examples of additional and / or alternative current rise rates include rise rates of up to 1,000,000 A / s, 900,000 A / s, 800,000 A / s, 700,000 A / s, 600,000 A / s, 500,000 A / s, 400,000 A / s, 300,000 A / s, 200,000 A / s, or 100,000 A / s. These current rise rates may be sufficient to transition the impulse solenoid from the non-operating position 322 to the operating position 324 within a threshold transition time.

[0047] In some embodiments, the solenoid drive circuit may be configured to generate and / or provide an electrical impulse signal on a duty cycle. Examples of duty cycles are disclosed herein.

[0048] In some embodiments, and with reference to Figures 1-2 and 5, the solenoid drive circuit 360 may include a buffer circuit 370. The buffer circuit 370, if present, may be configured to selectively supply an electrical impulse signal 362 to the impulse solenoid 300. In some embodiments, the solenoid drive circuit 360 may additionally or alternatively include a converter 380. The converter 380, if present, may be configured to receive a power supply voltage 87 from the power cord 80 and / or battery 85 of the power tool 8, as shown in Figures 1-2, and to transform, boost, or buck the power supply voltage to an impulse voltage. In some embodiments, the converter 380 may include or be a boost converter, which may be configured to receive a power supply voltage from the power tool and boost the power supply voltage to an impulse voltage. In some embodiments, the converter 380 may include or be a buck converter, which may be configured to receive a power supply voltage from the power tool and buck the power supply voltage to an impulse voltage.

[0049] In a particular example, and as shown in Figure 5, the converter 380, in the form of a boost converter, includes an inductor 382, ​​a transistor 384, and a diode 386. The inductor 382 may be configured to receive a power supply voltage 87 and supply the power supply voltage to both the transistor 384 and the diode 386. The transistor 384 may be configured to selectively ground the output from the inductor 382 400 and generate a voltage spike at node 388. The voltage spike may have an amplitude greater than the power supply voltage 87. The diode 386 may be configured to rectify the voltage spike and provide the rectified current 387 to the buffer circuit 370.

[0050] The buffer circuit 370 may include at least one diode 372, at least one capacitor 374, and at least one transistor 376. In a particular embodiment of Figure 5, the capacitor 374 receives a rectified current 387, such as an impulse voltage, and is thereby rechargeable. The impulse solenoid 300 can also receive a rectified current, and the transistor 376 can selectively establish either a high impedance between the transistor and ground 400 or a low impedance between the transistor and ground 400. In other words, the transistor 376 can selectively interrupt the connection between the impulse solenoid and ground, selectively disable the connection between the impulse solenoid and ground, and / or selectively isolate the impulse solenoid from ground.

[0051] Transistor 376 can selectively ground the output of the impulse solenoid 300 so that an electrical impulse signal 362 begins to flow through the impulse solenoid. Diode 372 interconnects the input and output of the impulse solenoid 300, shunting the output of the impulse solenoid to the input of the impulse solenoid and reducing the voltage drop across the impulse solenoid, while transistor 376 can provide a high impedance between the impulse solenoid and ground.

[0052] Figures 6 to 12 show examples of power tools 8 or their domain, including a safety brake 100 utilizing an actuator assembly 160 in the form of an impulse solenoid 300 according to this disclosure. Examples of power tools 8 include saws, rotary cutting tools, fastening tools, reciprocating tools, vibrating tools, woodworking tools, metalworking tools, automotive tools, handheld power tools, and / or portable power tools. Examples of saws include handheld circular saws, miter saws, radial arm saws, table saws, chop saws, plunge saws, track saws, bevel saws, band saws, curve saws, upcut saws, chainsaws, and / or panel saws. Examples of rotary cutting tools include routers, planers, joiners, sanders, drills, and / or grinders. Examples of fastening tools include screwdrivers, ratchets, and / or impact drivers. Examples of reciprocating tools include jigsaws and / or reciprocating saws. Examples of vibrating tools include sanders and / or multi-tools.

[0053] In examples of power tools 8, including handheld and / or portable power tools, it may be desirable to reduce and / or minimize the dimensions, volume, and / or weight of the safety brake 100. This is because such handheld and / or portable power tools may have constraints on their overall dimensions and / or weight. In consideration of this, the small size and / or weight of the impulse solenoid 300 used to operate the safety brake 100 allows the safety brake 100 according to this disclosure to be introduced into power tools that could not utilize conventional safety brakes due to their size and weight, and / or facilitates such introduction.

[0054] As described above, the power tool 8 can be configured to perform work on a workpiece. Examples of work include cutting, sawing, grinding, turning, drilling, and / or fastening of the workpiece. Examples of workpieces include materials to be cut, materials to be removed, materials to be drilled, bolts, screws, and / or nuts. The power tool 8 can utilize tools 40 to perform work. Examples of tools 40 include any suitable bit, blade, socket, grinding wheel, chain, and / or polishing pad.

[0055] As collectively shown in Figures 6 to 12, the power tool 8 may include a motor 20. The motor 20 may be configured to provide driving force for the operation or movement of the fixture 40. In some examples, the power tool 8 may include a fixture holder 30, which may be configured to operably mount the fixture 40 to the power tool and / or to transmit driving force from the motor to the fixture. Examples of motors 20 include electric motors, AC electric motors, DC electric motors, brushless DC electric motors, variable speed motors and / or single speed motors. Examples of fixture holders 30 include clamps, fixtures, bars, guide rails and / or arbors.

[0056] The power tool 8 may include any suitable power source and corresponding power supply structure for supplying power to the motor 20 and / or safety brake 100. Examples of power sources include a power cord 80 and / or battery 85, and it is within the scope of this disclosure that the same or different power sources may be used for the motor 20 and the safety brake 100.

[0057] The power tool 8 may include a grip area 50. The grip area 50, if present, can be configured to be gripped by the user of the power tool. An example of the grip area 50 is a handle. The power tool 8 may also include a switch 55. The switch 55, if present, can be configured to be selectively actuated by the user of the power tool and / or to selectively apply current to a motor 20, such as a power motor 20. Examples of the switch 55 include an electric switch, a normally open electric switch, a momentary electric switch and / or a locked momentary electric switch.

[0058] The power tool 8 may also include a workpiece support 70. The workpiece support 70, if present, can be configured to support the workpiece and / or to position the power tool relative to the workpiece when working with the workpiece.

[0059] In addition to the actuator assembly 160, a safety brake 100 may be included in the brake assembly 120. As will be described in more detail herein, the brake assembly 120 may be configured to transition between or be transitioned between a disengaged configuration 140, shown by a dashed line in Figure 6 and solid lines in Figures 7 and 9, and an engaged configuration 142, shown by a dotted line in Figure 6 and solid lines in Figures 8 and 11. The transition may be in response to and / or a result of a transition of the impulse solenoid 300 of the actuator assembly 160 from a non-operated state 302, shown in Figures 1 and 3, to an operated state, shown in Figure 2. When in the disengaged configuration 140, the brake assembly 120 separates from the device 40 and / or allows the device to move. When in the engaged configuration 142, the brake assembly operably engages with the device 40 and / or resists the movement of the device. In some embodiments, as will be described in more detail herein, the brake assembly 120 may include a brake cam 130.

[0060] In some embodiments, the power tool 8 includes and / or is a circular saw 10, and Figures 7 to 12 show examples of the power tool 8 including the circular saw 10. The power tool 8, such as the circular saw 10, includes a motor 20, a tool holder 30 which is, for example, an arbor, and / or a tool 40 which is, for example, a circular saw blade. The motor includes a motor shaft 22 configured to rotate about a shaft rotation axis 24, as shown in Figures 7 to 8. The tool holder is operably mounted directly or indirectly to the motor shaft. The tool is operably mounted to the power tool via the tool holder. The power tool 8 including the circular saw 10 also includes a safety brake 100 which defines a tool receiving area 102 as shown in Figures 7 to 11, and a tool 40 which extends at least partially within the tool receiving area. If the tool 40 includes a circular saw blade, the tool receiving area 102 may also be referred to herein as the blade receiving area.

[0061] The following discussion will describe specific examples of power tools 8 in the form of a circular saw 10, including the safety brake 100 provided in this disclosure. Any structure, function and / or feature disclosed herein with respect to the circular saw 10 may be appropriately included in and / or utilized in any suitable power tool provided in this disclosure, as is within the scope of this disclosure. With this in mind, a reference to the circular saw 10 may also be a reference to the power tool 8 and / or the power tool 8, a reference to the circular saw blade 40 may also be a reference to the tool 40, a reference to the blade support area 102 may also be a reference to the tool support area 102, and / or a reference to the rotation of the circular saw blade 40 may also be a reference to the motion of the tool 40.

[0062] During the operation of the circular saw 10, as will be described in more detail herein, the motor 20 is available to provide a driving force to rotate the motor shaft 22 and the mounted circular saw blade 40 around the shaft rotation axis 24. The circular saw blade 40 may include teeth 48, as shown in Figures 7 to 11, and by rotating the circular saw blade around the shaft rotation axis, cutting of a workpiece can be enabled and / or facilitated by the circular saw, through the circular saw, and / or using the circular saw.

[0063] Compared to conventional circular saws that do not include a safety brake 100, the circular saw 10 according to this disclosure includes additional safety features that can protect the user from injuries that may result from contact between the user and the circular saw blade while the circular saw blade is rotating. More specifically, as will be described in more detail herein, the circular saw 10 is configured to detect potentially injuring conditions and, in response to such detection, immediately stop the rotation of the circular saw blade, thereby limiting and / or avoiding injury. The rotation of the circular saw blade can be stopped by transitioning the brake assembly 120 of the safety brake 100 from an unengaged configuration 140, as shown in Figures 7 and 9, to an engaged configuration 142, as shown in Figures 8 and 11. This transition from the unengaged to the engaged configuration will also be discussed in more detail herein.

[0064] As shown by dashed lines in Figures 7 and 8, the circular saw 10 may include a blade guard 60. The blade guard 60 may be configured to cover, retract, and / or encompass at least a portion of the circular saw blade 40, if present, to prevent or reduce the possibility of contact between the user and the circular saw blade. The blade guard 60 may include a retractable area 62, which may be configured to fold, rotate, and / or retract in any other way when the circular saw is used to cut a workpiece. In some embodiments of the circular saw 10, at least one area 64 of the blade guard 60 may be defined by and / or encompass a safety brake. In other words, the safety brake 100 may function as at least an area 64 of the blade guard 60 by preventing contact between the user of the circular saw and the circular saw blade 40 extending into the blade receiving area 102.

[0065] In Figures 7-8, the circular saw 10 may include a clutch 90, which is also referred to herein as a safety clutch 90. The clutch 90 can be configured to reduce the possibility of damage to at least one component of the circular saw, such as the motor 20, motor shaft 22, arbor 30, the gear train of the circular saw, and / or the safety brake 100, when the safety brake 100 transitions from its disengaged configuration 140 to an engaged configuration 142, for example, to stop the rotation of the circular saw blade 40, if present. This reduction in the possibility of damage can be achieved by at least mechanically discoupling the circular saw blade 40 from the motor shaft 22, i.e., decoupling it, thereby making the rotation of the motor shaft 22 independent of the rotation of the circular saw blade 40, reducing the rotational mass, i.e. momentum, that must be stopped by the safety brake 100, and / or causing the motor shaft 22 to rotate and stop more slowly than the circular saw blade 40. The clutch 90 may be incorporated into, defined within, and / or defined as at least a part of, the arbor 30, the gear train of the circular saw, and / or the belt drive assembly of the circular saw.

[0066] The clutch 90 can operate in any suitable manner. For example, the clutch 90 can be configured to selectively allow rotation between the circular saw blade and the motor shaft, i.e., relative rotation, when the torque between the circular saw blade and the motor shaft exceeds a threshold torque. For example, the clutch 90 can be configured to resist rotation between the circular saw blade and the motor shaft, i.e., relative rotation, when the torque between the circular saw blade and the motor shaft is below a threshold torque. Examples of the clutch 90 include torque limiting clutches and friction clutches.

[0067] As shown in Figures 7-8 and discussed in more detail herein, the power tools 8, circular saws 10 and / or their safety brakes 100 may include a sensor assembly 110 configurable to detect operating parameters. The operating parameters may indicate that the actuator assembly should be utilized to actuate and / or engage the safety brake. Examples of operating parameters include undesirable event parameters that suggest an undesirable event or the possibility of such an event to be avoided using or by using the power tools and / or circular saw. Another example of an operating parameter is a kickback parameter that suggests a kickback or the possibility of kickback of the power tools and / or circular saw. Another example of an operating parameter is a motion parameter that suggests an undesirable movement or the possibility of such movement of the power tools and / or circular saw. Yet another example of an operating parameter is a proximity parameter that suggests the distance between an individual, such as the user of the power tools and equipment, and the equipment is less than a threshold distance. In various embodiments, and as will be described in more detail herein, proximity parameters may indicate contact between a person and the instrument and / or circular saw blade, imminent contact between a person and the instrument and / or circular saw blade, and / or the distance between a person and the instrument and / or circular saw blade is less than the small finite distance disclosed herein in its examples.

[0068] Continuing to refer to Figures 7 and 8, the circular saw 10 may include a blade isolation structure 95 to improve the sensitivity, signal-to-noise ratio, and / or the likelihood of misreading of the sensor assembly. The blade isolation structure 95 may be configured to electrically isolate the circular saw blade 40 from at least one other component of the circular saw, if present. Examples of at least one other component of the circular saw include the grip area 50, the switch 55, the outer surface of the circular saw, and / or areas of the circular saw that may be touched by the user when the circular saw is used to cut a workpiece. As an addition or alternative, the blade isolation structure 95 may be configured to electrically isolate the circular saw blade 40 from ground or earth.

[0069] The safety brake 100 has been described above as being included in and / or a component of the saw 10. It is within the scope of this disclosure that the safety brake 100 may be included in the circular saw 10 in any suitable form. For example, the circular saw 10 may be supplied by its manufacturer with the safety brake 100 already incorporated and / or included. For another example, the safety brake 100 may be configured to be included in, installed and / or retrofitted to an existing circular saw that did not necessarily include the safety brake 100 when it was first manufactured and / or sold by the manufacturer. In consideration of this, the following discussion of the safety brake 100 may refer to the safety brake 100 incorporated into the circular saw 10 and / or the safety brake 100 that may be manufactured and / or sold as a replacement safety brake 100 for the circular saw 10 and / or the safety brake 100 that may be manufactured and / or sold for retrofitting to an existing circular saw that did not include a safety brake.

[0070] As shown in Figures 7 to 11, the safety brake 100 is configured to function as a safety brake for the circular saw blade 40 of the circular saw 10. As shown in Figures 7 to 8, the safety brake 100 includes a sensor assembly 110, a brake assembly 120, and an actuator assembly 160. As previously stated, the sensor assembly 110 is configured to detect operating parameters, an example of which is disclosed herein. The operating parameters indicate that the actuator assembly should be used to actuate and / or engage the safety brake, for example, to stop the rotation of the circular saw blade. In other words, the sensor assembly 110 may be configured to detect unsafe conditions, such as the possibility of contact between a person and the circular saw blade and / or actual contact between a person and the circular saw blade. Thus, the sensor assembly 110 may be configured to generate a trigger signal 112, shown in Figures 7 to 8, in response to the detection of the operating parameters.

[0071] In some examples, the sensor assembly 110 may be configured to generate a trigger signal in response to, or immediately upon, contact between the person and the circular saw blade, or the commencement of contact. In some such examples, it may be referred herein as generating a trigger signal in response to the distance between the person and the circular saw blade being negligible and / or zero. In some examples, the sensor assembly 110 may be configured to generate a trigger signal in response to the distance between the person and the circular saw blade being a small, finite distance. Examples of such small, finite distances include less than 5 millimeters (mm), less than 4 mm, less than 3 mm, less than 2 mm, less than 1 mm, or less than 0.5 mm. In some such examples, the small finite distance is greater than zero.

[0072] As previously stated, the brake assembly 120 includes a brake cam 130. The brake assembly 120 and / or its brake cam 130 may be configured to transition between a disengaged configuration 140, as shown in Figures 7 and 9, and an engaged configuration 142, as shown in Figures 8 and 11. In the disengaged configuration 140, as shown in Figures 7 and 9, the brake cam is separated from the blade receiving area 102 of the safety brake 100 and / or does not contact the blade 40 of the circular saw 10. In contrast, in the engaged configuration 142, the brake cam extends into the blade receiving area 102 and is configured to operably engage with the flat side surface 42 of the circular saw blade 40 to resist and / or stop the rotation of the circular saw blade, as shown in Figures 8 and 11. The flat side surface 42 may also be referred to herein as the flat side of the fixture.

[0073] The actuator assembly 160 is configured to selectively transition the brake assembly 120 and / or its brake cam 130 from an unengaged configuration to an engaged configuration. This selective transition can be performed in response to and / or as a result of receiving a trigger signal from the sensor assembly and / or the actuator assembly. This selective transition is schematically shown in Figures 7 and 8 by the transition from the configuration in Figure 7 to the configuration in Figure 8, and / or in Figures 9 to 11 by the transition from the configuration in Figure 9 to the configuration in Figure 10 and subsequently to the configuration in Figure 11.

[0074] The brake assembly 120 may include any suitable structure, including a brake cam 130, which can be adapted, configured, designed and / or constructed to selectively stop the rotation of the circular saw blade and / or selectively transition between a non-engaged configuration 140 and an engaged configuration 142. In some examples, the brake assembly 120 may include and / or be a non-destructive brake assembly, which can be configured to selectively stop the rotation of the circular saw blade without damaging the circular saw blade and / or the brake assembly. In some examples, the brake assembly 120 may include or be a resettable brake, which can be configured to selectively and repeatedly transition between a non-engaged configuration and an engaged configuration, as will be described in more detail herein. In some examples, the brake assembly may include only one, i.e., a single brake cam 130. However, it is also within the scope of this disclosure that the brake assembly 120 may include two or more brake cams 130, such as a plurality of brake cams 130.

[0075] As previously mentioned, the brake assembly 120 and / or its brake cam 130 may be configured to selectively engage with the flat side surface 42 of the circular saw blade 40. With this in mind, it can be said that the brake assembly 120 and / or brake cam 130 are not engaged with and / or separated from the teeth 48 of the circular saw blade. This may include not engaging with and / or being separated from the teeth both when the brake cam is in the non-engaged configuration 140 and when the brake cam is in the engaged configuration 142.

[0076] As shown by the transition from the configuration in Figure 7 to the configuration in Figure 8 and / or the transition from the configuration in Figure 9 to the configuration in Figure 11, the brake cam 130 may be configured to rotate around the cam rotation axis 138 to selectively transition from a disengaged configuration 140 to an engaged configuration 142 and / or between the disengaged and engaged configurations, or the brake cam may selectively transition. In some embodiments, the blade receiving area 102 may include and / or be a flat, or at least substantially flat, blade receiving area 102. In such embodiments, the rotation axis 138 of the cam may be parallel or substantially parallel to the flat blade receiving area. In other words, the cam rotation axis 138 may be parallel, or at least substantially parallel to the flat side surface 42 of the circular saw blade 40. In some embodiments, the cam rotation axis 138 may be perpendicular or substantially perpendicular to the actuation axis 166 of the actuator assembly 160, as shown in Figures 7 to 11.

[0077] As shown by dashed lines in Figures 7-8 and solid lines in Figures 9-12, the safety brake 100 and / or its brake cam 130 may include a brake assembly biasing mechanism 144, also referred to herein as a cam biasing mechanism 144. The cam biasing mechanism 144 may be configured to bias the brake cam 130 toward and / or into the disengaged configuration 140. In other words, the cam biasing mechanism 144 can keep the brake cam 130 in the disengaged configuration 140 unless it is pushed out of and / or toward the engaged configuration 142 by an actuator assembly 160 or the like. Examples of the cam biasing mechanism 144 include an elastic cam biasing mechanism, a cam biasing spring, and / or a cam biasing torsion spring.

[0078] The cam biasing mechanism 144 can be defined in any suitable form. For example, as shown in Figures 9 to 11, the cam biasing mechanism 144 can bias the brake cam 130 via a biasing force applied between the brake cam 130 and the structure defining the cam rotation axis 138. As another example, as shown in Figure 12, the cam biasing mechanism 144 may be operably mounted to the actuator assembly 160, for example via a brake assembly biasing mechanism base 350, to apply a biasing force between the brake cam and the actuator assembly.

[0079] The brake cam 130 may have and / or define a blade engagement surface 134, as shown in Figures 7 to 11, which may also be referred to herein as the tool engagement surface 134. The blade engagement surface 134 may be configured to operably engage with the tool and / or the flat side surface 42 of the circular saw blade, for example, when the brake cam is in the engagement configuration 142. In some examples, the blade engagement surface 134 may be shaped such that as the brake cam rotates around the axis of rotation 138 of the cam and / or as the brake cam transitions from the non-engagement configuration 140 to the engagement configuration 142, the brake cam presses increasingly harder against the flat side surface of the circular saw blade. In some such examples, the brake cam 130 may have a region 158 with a gradually increasing radius and a region 159 with a constant radius, examples of which are schematically shown in Figures 7 to 11.

[0080] In some such embodiments, the brake cam may be configured to first engage with the circular saw blade in a region of increasing radius, in an intermediate configuration 141 best shown in Figure 10, and then engage with the circular saw blade in a region of constant radius. In the region of increasing radius, the distance between the cam rotation axis 138 and the blade engagement surface 134 increases in a plane perpendicular to the cam rotation axis, thereby allowing the brake cam to press against the circular saw blade with an increasingly stronger force as it contacts and rotates against the circular saw blade. In the region of constant radius, as discussed earlier, the distance between the cam rotation axis 138 and the blade engagement surface 134 is constant in a plane perpendicular to the cam rotation axis, thereby allowing the brake cam to press against the circular saw blade with a constant, or at least substantially constant, force as it contacts and rotates further against the circular saw blade.

[0081] In some embodiments, the blade engagement surface 134 may be shaped such that, in response to contact between the brake cam and the flat side surface of the circular saw blade, the brake cam automatically stops and / or automatically transitions to the engagement configuration. For example, as shown in Figure 10, the contact between the blade engagement surface 134 of the brake cam 130 and the circular saw blade 40 allows the brake cam to be pushed into the engagement configuration 142 in Figure 11, by means of the rotation of the circular saw blade and the frictional force between the brake cam and the circular saw blade.

[0082] In some examples, the blade engagement surface 134 may have or define an eccentric profile or shape with respect to the cam rotation axis 138. More specifically, the blade engagement surface 134 may have or define a logarithmic spiral profile or shape. The specific shape and / or profile of the blade engagement surface 134 may be designed and / or selected based on the coefficient of friction between the flat surface 42 and the brake cam 130 so as to provide the blade 40 with the desired stopping force when the brake cam transitions to the engagement configuration. In another example, friction between the brake cam and the flat surface, once initiated, can drive the brake cam toward and / or toward the engagement configuration.

[0083] In other words, the safety brake 100, brake cam 130, and / or brake engagement surface 134 may be configured such that the frictional force between the circular saw blade and the brake cam during the rotation of the circular saw blade drives the brake cam toward the engagement configuration 142, thereby forcing it into the engagement configuration 142. Thus, once the actuator assembly 160 brings the brake cam 130 into contact with the circular saw blade, the frictional force causes the brake cam to exert an increasingly large stopping force on the circular saw blade, ultimately bringing the circular saw blade to a stop. This configuration may be referred to herein as a self-forcing safety brake.

[0084] In some examples, the brake cam 130 may include a cam friction material 136, which can be selected to define the blade engagement surface 134 and / or increase the coefficient of friction between the blade engagement surface and the circular saw blade. Examples of cam friction material 136 include diamond coatings, abrasives, abrasive grain coatings, ceramic materials, sintered materials and / or metal alloys.

[0085] In some examples, the blade engagement surface 134 is integrated with and / or defined by the brake cam 130. In other examples, the blade engagement surface can be applied to and / or cover the brake cam. In other examples, the brake cam 130 may include a blade engagement surface insert 132, as shown in Figures 7-8. The blade engagement surface insert 132 may also be referred to herein as an instrument engagement surface insert. The blade engagement surface insert 132, if present, is operably mounted to the rest of the brake cam and forms and / or defines the blade engagement surface 134 and / or includes or may be defined by a cam friction material 136. In some such examples, the brake cam 130 and / or the blade engagement surface insert 132 may be configured to be repaired and / or replaced after wear exceeding a threshold amount and / or after the brake cam has been transitioned from a non-engaged configuration to an engaged configuration more than a threshold number of times. As an addition or alternative, the brake cam 130 may be configured to be repaired and / or replaced.

[0086] The safety brake 100, brake assembly 120, and / or brake cam 130 may be configured such that when transitioning from a non-engaged configuration 140 to an engaged configuration 142, the brake cam remains in the engaged configuration. Such safety brakes 100, brake assembly 120, and / or brake cam 130 may be referred to herein, respectively, as a self-locking safety brake 100, a self-locking brake assembly 120, and / or a self-locking brake cam 130.

[0087] For example, the safety brake 100, brake assembly 120, and / or brake cam 130 can be configured to remain engaged until, for example, the brake cam is released from the engaged configuration by the user of the circular saw. In other words, as will be described in more detail herein, transitioning the brake assembly 120 from the engaged configuration to the disengaged configuration may require the user to activate the reset mechanism 146. This can further improve the safety of the circular saw 10, including the safety brake 100, by allowing the user to recognize and correct the state in which the brake assembly has been transitioned to the engaged configuration before the next circular saw operation.

[0088] The safety brake 100, brake assembly 120, and / or brake cam 130 can be made to remain in and / or be within the engagement configuration using any suitable mechanism. For example, the brake cam 130 may be shaped to remain in the engagement configuration. More specifically, the brake cam 130 may include a locking region and / or a flat region that holds the brake cam in the engagement configuration. In another example, an operational engagement and / or force between the circular saw blade and the brake cam may hold the brake cam in the engagement configuration.

[0089] The brake assembly 120 may include a stopper 170 as shown in Figures 7 to 11. The stopper 170, if present, can be configured to restrict the rotation of the brake cam 130, for example, around the cam rotation axis 138. In some embodiments, the stopper 170 may include a disengaged stopper 172, which may be configured to restrict the rotation of the brake cam away from the blade receiving area 102 when the brake cam is in a disengaged configuration. In some embodiments, the stopper 170 may include an engaged stopper 174, which may be configured to restrict the rotation of the brake cam toward and / or into the blade receiving area 102 when the brake cam is in an engaged configuration.

[0090] It is within the scope of this disclosure that the stop portion 170 can be defined in any suitable form. For example, the stop portion 170 in the form of an engaging stop portion 174 can be defined at least partially by the brake cam 130, such as by the shape and / or profile of the brake cam, such as a flat region of the brake cam that limits its rotation. In another example, the stop portion 170 can be configured to operably engage with the brake cam to limit the rotation of the brake cam, for example, when the actuator arm 164 of the actuator assembly 160 engages with the brake assembly and / or brake cam as shown in Figures 9 to 11. In yet another example, the stop portion 170 in the form of an engaging stop portion 174 may include and / or be the structure and / or surface of the brake assembly 120 that engages with the brake cam when the brake cam reaches the engaging configuration 142. In yet another example, the stop portion 170 in the form of a non-engaging stop portion 172 can be defined at least partially by the actuator arm 164.

[0091] As shown in Figures 7-8, the brake assembly 120 may include a housing 180, which is also referred to herein as the caliper 180. The housing 180 can be configured to operably support the brake cam 130 and / or the actuator assembly 160. Additionally or alternatively, the housing 180 may at least partially enclose the blade receiving area 102. The housing 180 may be formed of a mechanically rigid material such as metal or plastic. Such a configuration can reduce the deflection when the brake cam 130 transitions to the engaged configuration and / or reduce the time required to stop the rotation of the circular saw blade when the brake cam transitions from the disengaged configuration to the engaged configuration.

[0092] The housing 180 may include a split housing configured to be disassembled into two or more separate housing regions 182. In such a configuration, the brake assembly 120 can be reset and / or transitioned from an engaged configuration to a disengaged configuration by separating the housing regions 182, as will be described in more detail herein.

[0093] As shown in Figures 7 to 11, the safety brake 100 and / or its brake assembly 120 may include a brake pad 190 in addition to the brake cam 130. The brake pad 190 may include a pad friction material 192, if present. An example thereof is disclosed herein with respect to a cam friction material 136. The brake pad 190 can be positioned inside the brake assembly 120 and / or relative to the brake cam 130. For example, the pad friction material 192 may be positioned facing the brake cam 130, facing the blade receiving area 102 and / or facing the circular saw blade 40. Additionally or alternatively, the brake pad 190 may be positioned such that the blade receiving area 102 extends at least partially between the brake pad and the brake cam. The brake assembly 120 can be configured such that, when the brake assembly is in an engaged configuration, at least a portion of the instrument 40, such as a circular saw blade, is compressed between the brake pad 190 and the brake cam 130.

[0094] In some embodiments, the brake cam 190 may include a pivot pad base 230, as shown in Figures 7-8. The pivot pad base 230, if present, may be configured to allow limited rotation of the brake pad 190 about a pivot point 232. Additionally or alternatively, the pivot pad base 230 may be configured to allow limited rotation of the brake pad 190 about at least one pivot axis, or more pivot axes. In such configurations, misalignment of the brake assembly 120 and / or the circular saw blade and / or deflection of the brake assembly 120 and / or the circular saw blade is made possible, and the friction surface 244 of the brake pad 190 may be aligned with or flat against the circular saw blade. This may enable and / or facilitate a uniform load and / or force distribution between the circular saw blade 40 and the brake pad 190 and / or its friction surface 244.

[0095] This uniform load and / or force distribution between the brake pad and the saw blade may also enable and / or facilitate a uniform load and / or force distribution between the brake cam and the circular saw blade. Such a uniform load and / or force distribution may reduce the magnitude of point forces in the various components of the circular saw. This may enable the use of lighter components, reduce component wear, and / or increase the product life of the components. The friction surface 244 partially or entirely includes a flat, or at least substantially flat, friction surface 244. This may constitute at least partial, or full, face-to-face contact with the flat side surface of the circular saw blade.

[0096] As shown by dashed lines in Figures 7 and 8, the brake assembly 120 may include an adjustment mechanism 194. The adjustment mechanism 194 may be configured to selectively adjust or be used for selective adjustment of the distance 196 between the brake pad and the brake cam, as shown in Figure 7, if present. Such adjustment makes available and facilitates the use of circular saw blades 40 of different thicknesses in the circular saw 10, and / or regardless of the thickness and / or other characteristics of the circular saw blade, allowing the safety brake 100 to define a desired spacing between the brake pad 190 and the circular saw blade. As an example, the adjustment mechanism 194 may include a detent for a given and / or specific circular saw blade thickness. An example of an adjustment mechanism 194 is a threaded fastener configured to adjust the distance between the brake pad and the brake cam.

[0097] The circular saw blade 40 may include a plurality of flat sides 42, including a first flat side 44 and a second flat side 46 that may be opposed to the first flat side. In other words, the tool 40 may include both the first flat side 44 and the second flat side 46. In such a configuration, the brake cam 130 may be configured to operably engage with the first flat side 44, and the brake pad 190 and / or, if any, its pad friction material 192 may be configured to operably engage with the second flat side 46 of the circular saw blade.

[0098] The safety brake 100 may include a mounting mechanism as shown in Figures 7-8, which can be configured to operably mount at least a portion of the safety brake, such as the brake cam 130, actuator assembly 160, housing 180 and / or brake pad 190, to the circular saw 10. In some embodiments, the mounting mechanism 200 can maintain a fixed, or at least substantially fixed, relative orientation between the blade receiving area 102 and the rest of the circular saw. In some embodiments, the mounting mechanism 200 may include a floating mounting mechanism, or a floating mounting mechanism in which the blade receiving area 102 may be configured to operably translate relative to the rest of the circular saw, for example, along a float axis 204 perpendicular to, or at least substantially perpendicular to, the flat side surface 42 of the circular saw blade. Such a configuration allows the brake pad 190 to remain fixed, or at least substantially fixed, to the housing 180 while the brake assembly 120 is being operated from a disengaged configuration to an engaged configuration, while in the engaged configuration, both the brake pad 190 and the brake cam 130 can be engaged with the circular saw blade 40. An example of a floating mounting mechanism 200 is a mounting pin 202 or a number of mounting pins 202. In such a configuration, the mounting mechanism can be configured to allow the blade receiving area 102 to be movably translated relative to the rest of the circular saw along the longitudinal axis of the mounting pin, such as a float axis 204.

[0099] The actuator assembly 160 may include a power source 162 as shown in Figures 7-8. The power source 162, which is part of and / or can be defined by the solenoid drive circuit 360 in Figures 1-2 and 5-6, can be configured to supply power to the actuator assembly. In some embodiments, the power source 162 can be configured to supply power to the actuator assembly even when the main power source of the circular saw cannot supply power to the motor 20. Examples of power sources 162 include electrical power sources such as mains power, AC power, DC power, battery and / or capacitor.

[0100] As previously stated, the actuator assembly 160 may include an actuator arm 164, as shown in Figures 1-3 and 9-12. The actuator arm 164 can be configured to selectively extend from the actuator assembly and / or selectively transition the brake assembly and / or brake cam from a disengaged configuration to an engaged configuration. As also previously stated, the actuator arm 164 may include and / or be a solenoid armature 320 of the impulse solenoid 300. The actuator arm 164 in the form of a solenoid armature can physically and directly contact the brake assembly 120 and / or brake cam 130 when the brake assembly transitions from a disengaged configuration to an engaged configuration. In other words, the brake assembly 120 may not have an intervening mechanical linkage and / or pivot linkage interconnecting the actuator arm and the brake cam. Such a configuration can reduce the total weight of the moving parts in the brake assembly and / or increase the speed at which the brake assembly transitions from a disengaged configuration to an engaged configuration.

[0101] Referring to Figures 7 and 8, the sensor assembly 110 may include any suitable structure that can be adapted, configured, designed and / or constructed to detect operating parameters and / or generate a trigger signal. An example of the sensor assembly 110 is a capacitive sensor assembly configured to detect operating parameters. Further examples and / or other components of the sensor assembly 110 that can be incorporated into and / or used in the circular saw 10 and / or safety brake 100 according to this disclosure are disclosed in U.S. Patents 7,536,238, 7,971,613, 9,724,840 and International Patent Application Publication WO2017 / 210091, the entirety of which are incorporated herein by reference.

[0102] Continuing to refer to Figures 7 and 8, the safety brake 100 may include a deflection-relieving structure 210, which may define at least partially the blade receiving area 102. The deflection-relieving structure 210 can be configured, if present, to prevent the instrument, such as a saw blade, from deflecting and contacting the brake assembly 120 and / or its brake cam 130 when the instrument is being used to cut a workpiece and the brake assembly is in an unengaged configuration. In other words, in some examples, the workpiece may cause the circular saw blade to deflect in the direction of the brake cam. As discussed herein, the brake cam 130 may be configured to automatically transition to an engaged configuration, for example, via frictional force between the circular saw blade and the brake cam, when it comes into contact with a rotating circular saw blade. Such a transition may be undesirable during normal cutting operation of the circular saw or without detection of operating parameters. Thus, the deflection-relieving structure 210 can be used to reduce the possibility of this undesirable contact between the circular saw blade and the brake cam.

[0103] The deflection-relieving structure 210 can resist contact between the circular saw blade and the brake cam in any appropriate manner. For example, the deflection-relieving structure 210 may include a deflection-relieving surface 212, which can be configured to operably contact the tool 40 when the tool deflects in the direction of the brake cam. In a specific example, the deflection-relieving surface 212 may be positioned to contact the circular saw blade 40 before the circular saw blade deflects and contacts the brake cam. As a result, the deflection-relieving surface 212 can prevent contact with the brake cam due to the deflection of the circular saw blade.

[0104] As will be described in more detail herein with respect to the blade insulation structure 95, it may be desirable to electrically insulate the circular saw blade 40 from one or more other components of the circular saw 10. In consideration of this, at least the deflection-relieving surface 212 of the deflection-relieving structure 210 may be electrically insulated from the rest of the circular saw blade.

[0105] In some embodiments, the deflection-relieving structure 210 includes an electrical isolation structure 214, also referred to herein as an electrical isolation spacer 214, which electrically isolates the circular saw blade from one or more other components of the circular saw while the deflection-relieving structure and the circular saw blade are in contact. An example of an electrical isolation structure is an electrical insulator.

[0106] In some embodiments, the deflection-relieving structure 210 can be defined by an electrically insulating material that defines the deflection-relieving surface 212. Specifically, the deflection-relieving structure 210 can be defined at least partially or entirely by a ceramic material.

[0107] As already mentioned, after transitioning to the engaged configuration 142, the safety brake 100 can be configured to maintain the engaged configuration at least until the user of the circular saw transitions the circular saw to the disengaged configuration. With this in mind, the safety brake 100 can include a reset mechanism as shown in Figures 7 to 12. This allows the user of the circular saw to selectively transition the brake cam from the engaged configuration to the disengaged configuration, enabling continuous cutting of the workpiece by the circular saw.

[0108] An example of the reset mechanism 146 is an eccentric structure such as an eccentric shaft, an eccentric bushing, and / or an eccentric bearing. The eccentric structure may have an off-center lobe and / or may rotate to move or movably translate the brake cam away from the tool receiving area 102, the blade receiving area, the tool 40, and / or the circular saw blade 40. After moving away from the tool, the brake cam 130 may automatically rotate to a disengaged configuration.

[0109] Another example of the reset mechanism 146 is an adjustment mechanism 194, as shown in Figures 7 to 11, which is used to move the brake pad away from the circular saw blade, thereby returning the brake cam to a disengaged configuration. In such an example, the adjustment mechanism can be loosened using a tool such as a hex wrench, thereby moving the brake pad 190 away from the circular saw blade and returning the brake cam to a disengaged configuration.

[0110] Another example of the reset mechanism 146 is a housing 180 having a separate housing region 182, as shown in Figures 7-8, which is separable via fasteners or the like, thereby allowing the brake cam to be returned to a disengaged configuration. Another example of the reset mechanism 146 is a pressure-operated reset mechanism. A pressure-operated reset mechanism can be configured to release and / or reduce the pressure on the brake pad 190 and / or brake cam 130, translating the brake cam and / or brake pad away from the blade receiving region 102 and / or away from contact with the circular saw blade, thereby returning the brake cam to a disengaged configuration via the operation of the cam biasing mechanism 144. As an example, a pressure-operated reset mechanism may include a hydraulic cylinder, which is depressurized to move the brake pad 190 and / or brake cam 130 away from the circular saw blade and / or out of contact with the circular saw blade, thereby returning the brake cam to a disengaged configuration.

[0111] Another example of the reset mechanism 146 may include rotating the circular saw blade 40 in the opposite direction to the rotation of the circular saw blade when driven by the motor 20. This can be achieved by pressing the circular saw blade against the workpiece. Additionally or alternatively, the arbor 30 may be rotated in the opposite direction to the rotation of the circular saw blade when driven by the motor 20, using a tool such as a hex wrench. In either case, this rotation can rotate the brake cam 130 toward the disengaged configuration, thereby reducing the force that the brake cam exerts on the circular saw blade. After rotating by at least a threshold angle, the brake cam can be returned to the disengaged configuration, for example, through the operation of the cam biasing mechanism 144.

[0112] Another example of the reset mechanism 146 includes the rotating structures shown in Figures 7-8 and 12. The cam rotating structure 152 can be attached to and selectively attached to and / or associated with the brake cam 130, and / or the cam rotating structure can be configured to selectively rotate the brake cam away from the circular saw blade. For example, the cam rotating structure 152 can be selectively actuated by the user and configured to rotate the brake cam away from the circular saw blade, such as by engaging the cam rotating structure with a tool such as a wrench. In some embodiments, the cam rotating structure can be temporarily and / or selectively engaged with the brake cam. In another example, the cam rotating tool can be permanently, or at least substantially permanently, attached to the safety brake and / or configured to selectively engage with or interlock with the brake cam. The brake cam can be rotated away from the circular saw blade using the cam rotating tool. In some embodiments, the cam rotating structure may be a pretension lever or a structure including one, which can be biased by a lever spring.

[0113] As already stated, the safety brake 100 is available to protect the user of the circular saw 10 from injuries that may occur due to contact between the rotating circular saw blade and the user. To facilitate this protection, the brake assembly 120 may be configured to transition the brake cam 130 from a disengaged configuration to an engaged configuration within a threshold transition time. Examples of threshold transition times include transition times of at least 0.1 milliseconds (ms), at least 0.5 ms, at least 1 ms, at least 2 ms, at least 3 ms, at least 4 ms, at least 5 ms, up to 10 ms, up to 9 ms, up to 8 ms, up to 7 ms, up to 6 ms, up to 5 ms, up to 4 ms, up to 3 ms and / or up to 2 ms.

[0114] The speed at which the brake cam 130 transitions from an unengaged configuration to an engaged configuration can be measured and quantified by any suitable method. As an example, a high-speed camera with a frame rate of, for example, 50,000 frames per second was used to observe the circular saw blade and / or brake cam during the rotation of the circular saw blade. Light from an LED or the like was also made visible to the camera and configured to illuminate in response to a trigger signal received by the actuator assembly. In such a configuration, the time required for the brake assembly 120 to stop the rotation of the circular saw blade was quantified by counting the number of frames until the rotation of the circular saw blade stopped from the illumination of the light. The observed times were within the above range in various configurations.

[0115] In some embodiments, as shown by dashed lines in Figures 7-8, the power tool 8, circular saw 10 and / or safety brake 100 may include an interlock assembly 220. The interlock assembly 220 may be configured to allow or selectively allow the supply of current to the motor 20 when the safety brake 100 is configured to selectively resist the movement of the tool and / or the rotation of the circular saw blade, if it is present. Additionally or alternatively, the interlock assembly 220 may be configured to interrupt or selectively interrupt the supply of current to the motor when at least one component of the safety brake is not configured to selectively resist the movement of the tool and / or the rotation of the circular saw blade, or when it is not possible to do so. In other words, the interlock assembly 220 may be configured to allow the motor to move the device when the safety brake 100 is configured such that the safety brake is unable to protect an individual from contact with the device or the rotating circular saw blade, and to not allow or resist the movement of the device or the rotation of the circular saw blade when the safety brake 100 is configured such that the safety brake is unable to protect an individual from contact with the device or the rotating circular saw blade.

[0116] As an example, the interlock assembly 220 may include a sensor state detector configured to indicate the state of the sensor assembly 110. In some such examples, if the sensor state detector indicates that the sensor assembly is not configured to detect the operating parameters due to a failure of the sensor assembly and / or electrical interference with the sensor assembly, the interlock assembly 220 will not allow the motor to drive the rotation of the circular saw blade. Alternatively, if the sensor state detector indicates that the sensor assembly is configured to detect the operating parameters, the interlock assembly 220 may allow the motor to drive the rotation of the circular saw blade.

[0117] In another example, the interlock assembly 220 may include a brake assembly state detector configured to indicate the state of the brake assembly 120. In some such examples, if the brake assembly state detector indicates that the brake assembly is not configured to selectively resist the rotation of the circular saw blade, which may result from a brake assembly failure, a poorly prepared brake assembly, and / or failure by the operator to properly reset the brake assembly, the interlock assembly 220 may not allow the motor to drive the rotation of the circular saw blade. Additionally or alternatively, if the brake assembly state detector indicates that the brake assembly is configured to selectively resist the rotation of the circular saw blade, the interlock assembly may allow the motor to drive the rotation of the circular saw blade.

[0118] In yet another example, the interlock assembly 220 may include an actuator assembly state detector configured to indicate the state of the actuator assembly 160. In some such examples, if the actuator assembly state detector indicates that the actuator assembly is not configured to selectively force the brake cam into contact with the circular saw blade, for example, due to a failure of the actuator assembly and / or the accumulation of debris near the actuator assembly or brake cam, the interlock assembly 220 may not allow the motor to drive the circular saw blade to rotate. Alternatively, if the actuator assembly state detector indicates that the actuator assembly is configured to selectively force the brake cam into contact with the circular saw blade, the interlock assembly may allow the motor to drive the circular saw blade to rotate.

[0119] The interlock assembly 220 may, in addition or alternatively, include any suitable structure that is adapted, configured, designed and / or programmable to allow or selectively allow current to be supplied to the motor 20, if the safety brake 100 is configured to selectively resist the rotation of the circular saw blade. For example, the interlock assembly 220 may include a transistor, relay, switch, electrical switch and / or controller. If the interlock assembly 220 includes a controller, the controller is programmable to control the operation of the interlock assembly and / or perform the functions of the interlock assembly disclosed herein.

[0120] A power tool 8 including a safety brake 100, such as a circular saw 10 including a brake assembly 120, as disclosed herein, can be operated to protect an individual, such as the user of the power tool, from injury from contact with the working tool. Such operation is referred to herein as the method of operating the circular saw 500, and is shown in Figure 13.

[0121] Method 500 includes applying current in step 510 and moving the device in step 520. Method 500 may also include detecting operating parameters in step 530 and generating a trigger signal in step 540. Method 500 further includes transitioning the safety brake in step 550.

[0122] The application of current in step 510 may include, for example, applying current to the motor of a power tool for motor operation, activation, starting motion, movement, starting rotation and / or rotation. In some examples of method 500, as described in more detail herein, the power tool may include and / or be a battery-powered power tool. In such examples, the current is supplied by the battery of the battery-powered power tool. An example of a power tool is disclosed herein with respect to power tool 8. An example of a motor is disclosed with respect to motor 20.

[0123] The motion in step 520 may include the motion of the appliance of the power tool. This includes rotation, translation, rotation and / or reciprocating motion of the appliance. The motion in step 520 may be in response to, as a result of and / or following, the application of current in step 510. As an example, a power tool may be configured such that the motion of the motor drives the appliance. An example of an appliance is disclosed with respect to appliance 40.

[0124] The detection in step 530 may include the detection of any appropriate operating parameters, which may be performed during, or at least partially concurrently with, or after and / or in response to, the motion in step 520. The operating parameters may indicate undesirable events that should be avoided using and / or by the power tool. Additionally or alternatively, the operating parameters may suggest that the transition in step 550 should be initiated, for example, to avoid injury to the user of the power tool and / or damage to the workpiece being operated by the power tool. Examples of operating parameters are disclosed herein. An example of a sensor assembly that may be used for detecting operating parameters is disclosed herein with respect to sensor assembly 110.

[0125] The generation in step 540 may include generating a trigger signal in response to the detection in step 530. In such an example, the trigger signal may be provided to the actuator assembly, and the transition in step 550 may be in response to and / or result of the generation and / or reception of the trigger signal by the actuator assembly in step 540. An example of an actuator assembly is disclosed herein with respect to actuator assembly 160.

[0126] The transition in step 550 may involve transitioning the safety brake of the power tool from a disengaged configuration to an engaged configuration. The transition in step 550 may be performed after the detection in step 530 in response to and / or as a result of the detection. In the disengaged configuration, the safety brake allows or does not resist the movement of the tool. In the engaged configuration, the safety brake resists and / or stops the movement of the tool. The safety brake includes an actuator assembly including a solenoid drive circuit and an impulse solenoid. The solenoid drive circuit is configured to generate an electrical impulse signal in response to the detection of operating parameters, and the transition in step 550 includes providing the electrical impulse signal to the impulse solenoid to transition the impulse solenoid from a disengaged state to an engaged state, thereby transitioning the brake assembly from a disengaged configuration to an engaged configuration.

[0127] An example of a safety brake is disclosed herein with respect to safety brake 100. An example of a non-engaging configuration is disclosed herein with respect to non-engaging configuration 140. An example of an engaging configuration is disclosed herein with respect to engaging configuration 142. An example of a solenoid drive circuit is disclosed herein with respect to solenoid drive circuit 360. An example of an impulse solenoid is disclosed herein with respect to impulse solenoid 300.

[0128] In some embodiments, the transition in step 550 may include generating a magnetomotive force in the impulse solenoid and using that magnetomotive force as a driving force for the transition. In some examples, the transition in step 550 may include moving the solenoid armature of the solenoid through the armature movable region. In some examples, during the transition in step 550, the solenoid armature contacts or directly contacts the brake cam of the safety brake. An example of this is disclosed herein with respect to the brake cam 130.

[0129] As used herein, “and / or” placed between a first item and a second item means one of the following: (1) the first item, (2) the second item, and (3) the first item and the second item. Multiple items enumerated by “and / or” should be considered similarly, i.e., one or more items thus combined. In addition to the items specifically identified by “and / or,” other items may exist at will, whether related to or unrelated to the specifically identified items. Thus, as a non-restrictive example, the reference “A and / or B” when used with open-ended words such as “including,” may in one embodiment refer to A only (including items other than B at will), in another embodiment refer to B only (including items other than A at will), and in yet another embodiment refer to both A and B (including other items at will). These items may be elements, actions, structures, steps, operations, values, etc.

[0130] As used herein, the expression “at least one” in relation to an enumeration of one or more items should be understood to mean at least one item selected from any one or more of the enumerated items, and not necessarily to mean at least one of each or all of the specifically enumerated items in the item list, nor to exclude any combination of items in the item list. This definition allows for the existence of items other than those specifically identified in the item list referred to by the expression “at least one,” whether or not they relate to those specifically identified items, by choice. Therefore, as a non-restrictive example, the expression "at least one of A and B" (or equivalently, "at least one of A or B" or equivalently, "at least one of A and / or B") may, in one embodiment, refer to at least one that optionally includes two or more A's and does not include B's (and optionally includes items other than B's); in another embodiment, refer to at least one that optionally includes two or more B's and does not include A's (and optionally includes items other than A's); and in yet another embodiment, refer to at least one that optionally includes two or more A's and at least one that optionally includes two or more B's (and optionally other items). In other words, "at least one," "one or more," and "and / or" are open-ended expressions that function both conjunctively and disjunctively. For example, "at least one of A, B, and C", "at least one of A, B, or C", "one or more of A, B, and C", "one or more of A, B, or C", and "A, B, and / or C" can mean A only, B only, C only, A and B, A and C, B and C, A, B, and C, and any of the above combinations of at least one other item by choice.

[0131] If any patent, patent application, or other reference is incorporated by reference herein and (1) defines a term in a way that is inconsistent with any part of this disclosure other than the incorporated part and / or any other incorporated reference, and / or (2) otherwise inconsistent, the part of this disclosure not incorporated shall prevail, and the incorporated term or disclosure shall prevail only with respect to the reference in which the term is defined and / or the incorporated disclosure originally existed.

[0132] As used herein, the terms “adapted” and “configured” mean that an element, component, or other subject matter is designed and / or intended to perform a given function. Therefore, the terms “adapted” and “configured” should be understood to mean that a given element, component, and / or other subject matter is not merely “capable” of performing a given function, but rather that the element, component, and / or other subject matter is specifically selected, produced, implemented, utilized, programmed, and / or designed for the purpose of performing that function. Furthermore, it is within the scope of the invention that an element, component, and / or other described subject matter described as adapted to perform a particular function may, additionally or alternatively, be described as configured to perform the function, and vice versa.

[0133] As used herein, when the terms “for example,” “as an example,” and / or simply “example” are used in relation to one or more components, features, details, structures, embodiments, and / or methods provided herein, they are intended to convey that the components, features, details, structures, embodiments, and / or methods described are exemplary, non-exclusive examples of the components, features, details, structures, embodiments, and / or methods provided herein. Accordingly, the components, features, details, structures, embodiments, and / or methods described are not intended to be restrictive, essential, or exclusive / exclusive, and other components, features, details, structures, embodiments, and / or methods, including structurally and / or functionally similar and / or equivalent components, features, details, structures, embodiments, and / or methods, are also within the scope of this disclosure.

[0134] As used herein, “at least substantially” when modifying a degree or relationship may include not only the “substantial” degree or relationship mentioned, but also the entire extent of the degree or relationship mentioned. A substantial amount of the degree or relationship mentioned may include at least 75% of the degree or relationship mentioned. For example, an object that is at least substantially formed of a certain material includes an object in which at least 75% of the object is formed of that material, and also an object that is entirely formed of that material. As another example, a first length that is at least substantially equal to a second length includes a first length having a length no more than 75% of the second length, and also a first length that is the same length as the second length.

[0135] Exemplary, non-exclusive embodiments of the actuator assembly 160, power tool 8 and / or safety brake 100 according to the present disclosure are shown in the following numbered paragraphs. Within the scope of the present disclosure, individual steps of the methods referred to herein may be additionally or alternatively referred to as “steps for” performing the operations referred to herein, including in the following numbered paragraphs.

[0136] A1. An actuator assembly configured to selectively provide a driving force to transition a brake assembly for an electrically operated rear device from a disengaged configuration to an engaged configuration, This actuator assembly includes an impulse solenoid and a solenoid drive circuit. The impulse solenoid is configured to selectively transition from a non-operating state to an operating state in response to the reception of an electrical impulse signal. An impulse solenoid is configured to provide driving force during the transition from a non-operating state to an operating state. The solenoid drive circuit is configured to selectively generate an electrical impulse signal. The electrical impulse signal can be optionally configured to have an impulse voltage of up to 43 volts and an impulse duration of up to 10 milliseconds, and to transition the impulse solenoid from a non-operating state to an operating state with a transition time of up to 15 milliseconds.

[0137] A2. The actuator assembly in item A1 is configured to apply a driving force to the brake assembly to initiate a chain reaction of the brake assembly.

[0138] A3. The impulse solenoid is configured to generate a magnetomotive force in response to the reception of an electrical impulse signal, and to generate a driving force from that magnetomotive force. (i) at least 5,000 ampere-turns (At), at least 6,000 At, at least 7,000 At, at least 7,500 At, at least 10,000 At, or at least 12,500 At; (ii) Maximum 20,000 At, maximum 9,000 At, maximum 18,000 At, maximum 17,000 At, maximum 16,000 At, maximum 15,000 At, maximum 14,000 At, maximum 13,000 At, maximum 12,000 At, maximum 11,000 At or maximum 10,000 At, An actuator assembly having at least one of the sizes of A1 to A2.

[0139] A4. An impulse solenoid is an actuator assembly of any of items A1 to A3, which includes an impulse coil configured to receive an electrical impulse signal and generate a magnetic field in response to the reception of the electrical impulse signal.

[0140] A5. The impulse coil is defined, at least partially, by the windings of the actuator assembly in section A4.

[0141] A6. An actuator assembly according to Section A5, in which at least a portion of the windings are helical windings.

[0142] A7. The windings are, (i) at least 10 windings, at least 20 windings, at least 30 windings, at least 40 windings, at least 45 windings, at least 50 windings, at least 55 windings, at least 60 windings, at least 65 windings, at least 70 windings, at least 75 windings, or at least 80 windings; (ii) A maximum of 120 windings, a maximum of 110 windings, a maximum of 00 windings, a maximum of 90 windings, a maximum of 80 windings, a maximum of 75 windings, a maximum of 70 windings, a maximum of 65 windings, a maximum of 60 windings, a maximum of 55 windings, a maximum of 50 windings, a maximum of 45 windings, a maximum of 40 windings or a maximum of 30 windings, Includes at least one of the actuator assemblies described in A5 or A6.

[0143] A8. An actuator assembly according to any of sections A5 to A7, wherein the wires include at least one of conductive wires, aluminum wires, and copper wires.

[0144] A9. The wire (i) at least 0.3 mm, at least 0.4 mm, at least 0.5 mm, at least 0.6 mm, at least 0.7 mm, at least 0.8 mm, at least 0.9 mm, at least 1.0 mm, at least 1.1 mm, or at least 1.2 mm; (ii) at most 1.5 mm, at most 1.4 mm, at most 1.3 mm, at most 1.2 mm, at most 1.1 mm, at most 1.0 mm, at most 0.9 mm, at most 0.8 mm, at most 0.7 mm or at most 0.6 mm, An actuator assembly of any of items A5 to A8 having at least one diameter.

[0145] A10. The impulse coil is (i) at least 0.01 milliseconds (ms), at least 0.05 ms, at least 0.1 ms, at least 0.15 ms, or at least 0.2 ms; (ii) at most 0.4ms, at most 0.39ms, at most 0.38ms, at most 0.37ms, at most 0.36ms, at most 0.35ms, at most 0.34ms, at most 0.33ms, at most 0.32ms, at most 0.31ms, at most 0.30ms, at most 0.28ms, at most 0.26ms, at most 0.24ms, at most 0.22ms, at most 0.20ms, at most 0.18ms, at most 0.16ms, at most 0.14ms, at most 0.12ms or at most 0.10ms, An actuator assembly of any of terms A4 to A9 having at least one time constant.

[0146] A11. The impulse coil is (i) at least 0.01 millihenry (mH), at least 0.05 mH, at least 0.1 mH, at least 0.15 mH, or at least 0.2 mH; (ii) Maximum 0.44mH, maximum 0.42mH, maximum 0.40mH, maximum 0.38mH, maximum 0.36mH, maximum 0.34mH, maximum 0.32mH, maximum 0.30mH, maximum 0.28mH, maximum 0.26mH, maximum 0.24mH, maximum 0.22mH, maximum 0.20mH, maximum 0.18mH, maximum 0.16mH or maximum 0.14mH, An actuator assembly according to any of items A4 to A10, having at least one coil inductance.

[0147] A12. An impulse solenoid is an actuator assembly according to any of items A1 to A11, comprising a solenoid armature configured to move movably between a non-operated position and an operated position when the impulse solenoid transitions between a non-operated state and an operated state.

[0148] A13. The actuator assembly in Section A12 is configured such that the solenoid armature defines an elongated axis, and further, the solenoid armature performs linear translational motion along the elongated axis when the impulse solenoid transitions between a non-operated state and an operated state.

[0149] A14. An actuator assembly according to any of sections A12 to A13, wherein the solenoid armature is configured to operably engage with the brake assembly to selectively provide driving force to the brake assembly.

[0150] A15. An actuator assembly according to any of sections A12 to A14, wherein the solenoid armature can be configured to receive a magnetomotive force from an impulse coil and selectively apply a driving force to the brake assembly in response to the reception of that magnetomotive force.

[0151] A16. The solenoid armature is, (i) at least 1 gram (g), at least 2 g, at least 3 g, at least 4 g, at least 5 g, at least 6 g, at least 7 g, at least 8 g, at least 9 g, at least 10 g, at least 12 g, at least 14 g, at least 16 g, at least 18 g, at least 20 g, or at least 25 g; (ii) Maximum 40g, maximum 38g, maximum 36g, maximum 34g, maximum 32g, maximum 30g, maximum 28g, maximum 26g, maximum 24g, maximum 22g, maximum 20g, maximum 18g, maximum 16g, maximum 14g, maximum 12g, maximum 10g or maximum 8g, An actuator assembly of any of items A12 to A15 having at least one armature mass.

[0152] A17. The solenoid armature defines an armature movement range between a non-operating position and an operating position, and by arbitrary selection, the armature movement range is (i) at least 0.5 mm, at least 1.0 mm, at least 1.5 mm, at least 2.0 mm, at least 2.5 mm, at least 3 mm, at least 3.5 mm or at least 4.0 mm; (ii) Maximum 10mm, maximum 9.0mm, maximum 8.0mm, maximum 7.0mm, maximum 6.0mm, maximum 5.5mm, maximum 5.0mm, maximum 4.5mm, maximum 4.0mm, maximum 3.5mm, maximum 3.0mm, maximum 2.5mm or maximum 2.0mm, An actuator assembly from any of the sections A12 to A16, which is at least one of the following.

[0153] A17.1. A solenoid armature is an actuator assembly from any of sections A12 to A17, including a pin and an anchor operably attached to that pin.

[0154] A17.2. The anchor diameter of the anchor is greater than the pin diameter of the pin, as per section A17.1 of the actuator assembly.

[0155] A17.3. The actuator assembly in either section A17.1 or A17.2 defines a rounded pin end configured to engage with the brake assembly.

[0156] A17.4. The pin (i) at least 2 mm, at least 2.5 mm, at least 3 mm, at least 3.5 mm, at least 4 mm, at least 4.5 mm or at least 5 mm; (ii) Maximum 7mm, maximum 6.5mm, maximum 6mm, maximum 5.5mm, maximum 5mm, maximum 4.5mm, maximum 4mm, maximum 3.5mm or maximum 3mm, An actuator assembly according to any of sections A17.1 to A17.3, having at least one diameter.

[0157] A17.5. The anchor is (i) at least 10 mm, at least 10.5 mm, at least 11 mm, at least 11.5 mm, at least 12 mm, at least 12.5 mm, at least 13 mm, at least 13.5 mm or at least 14 mm; (ii) Maximum 17mm, maximum 16.5mm, maximum 16mm, maximum 15.5mm, maximum 15mm, maximum 14.5mm, maximum 14mm, maximum 13.5mm, maximum 13mm, maximum 12.5mm or maximum 12mm, An actuator assembly according to any of sections A17.1 to A17.4, having at least one anchor diameter.

[0158] A17.6. The solenoid armature is, (i) at least 25 mm, at least 30 mm, at least 35 mm, at least 40 mm, at least 45 mm, or at least 50 mm; (ii) Maximum 70mm, maximum 65mm, maximum 60mm, maximum 55mm, maximum 50mm, maximum 45mm or maximum 40mm, An actuator assembly according to any of clauses A12 to A17.5, specifying at least one armature length.

[0159] A17.7. The impulse solenoid further includes a cap, optionally (i) The cap is operably mounted on the solenoid armature and is configured to move together with the solenoid armature. (ii) The cap includes a central hole through which the solenoid armature extends. An actuator assembly that is at least one of the actuator assemblies described in sections A1 through A17.6.

[0160] A18. The impulse solenoid is, (i) To drive the impulse solenoid into a non-operating state, (ii) After receiving an electrical impulse signal from the impulse solenoid, the impulse solenoid is optionally switched from an operating state to a non-operating state. (iii) Driving the solenoid armature to the non-operating position, An actuator assembly from any of sections A1 to A17.7, further comprising a biasing mechanism configured to perform at least one of the following.

[0161] A19. The biasing mechanism is, (i) Elastic member (ii) spring (iii) Coil spring An actuator assembly according to item A18, including at least one of the following.

[0162] A20. The impulse voltage is, (i) at least 10 volts (V), at least 15V, at least 20V, at least 25V, at least 30V, at least 35V or at least 40V; (ii) A maximum of 42V, a maximum of 41V, a maximum of 40V, a maximum of 38V, a maximum of 36V, a maximum of 34V, a maximum of 32V, or a maximum of 30V; (iii) at least substantially equal to 42.4V, or 42.4V An actuator assembly from any of the categories A1 to A19, which is at least one of the following.

[0163] A21. The impulse duration is (i) at least 0.25 milliseconds (ms), at least 0.5 ms, at least 0.75 ms, at least 1.0 ms, at least 1.5 ms, at least 2.0 ms, at least 2.5 ms, at least 3.0 ms, at least 3.5 ms, at least 4.0 ms, at least 4.5 ms, at least 5.0 ms, at least 5.5 ms, at least 6.0 ms, at least 6.5 ms, at least 7.0 ms, at least 7.5 ms, or at least 8.0 ms; (ii) Maximum 9ms, maximum 8.5ms, maximum 8.0ms, maximum 7.5ms, maximum 7.0ms, maximum 6.5ms, maximum 6.0ms, maximum 5.5ms, maximum 5.0ms, maximum 4.5ms, maximum 4.0ms, maximum 3.5ms, maximum 3.0ms, maximum 2.5ms or maximum 2.0ms, An actuator assembly from any of the A1 to A20 clauses, which is at least one of the following.

[0164] A22. The solenoid drive circuit is, (i) at least 50 amps (A), at least 75A, at least 100A, at least 125A, at least 150A, at least 175A, at least 200A, at least 250A, at least 300A, at least 350A, at least 400A, at least 450A, at least 500A, at least 550A, at least 600A, at least 650A, at least 700A, at least 750A or at least 800A; (ii) Maximum 1000A, maximum 950A, maximum 900A, maximum 850A, maximum 800A, maximum 750A, maximum 700A, maximum 650A, maximum 600A, maximum 550A, maximum 500A, maximum 450A, maximum 400A, maximum 350A, maximum 300A or maximum 250A, An actuator assembly of any of items A1 to A21, configured to generate an electrical impulse signal having at least one impulse current.

[0165] A23. The solenoid drive circuit is, (i) at least 20,000 amperes per second (A / s), at least 25,000 A / s, at least 30,000 A / s, at least 35,000 A / s, at least 40,000 A / s, at least 45,000 A / s, at least 50,000 A / s, at least 55,000 A / s, at least 60,000 A / s, at least 70,000 A / s, at least 80,000 A / s, at least 90,000 A / s, at least 100,000 A / s, at least 200,000 A / s, at least 300,000 A / s, at least 400,000 A / s, at least 500,000 A / s, at least 600,000 A / s, at least 700,000 A / s, or at least 800,000 A / s; (ii) Maximum of 1,000,000 A / s, maximum of 900,000 A / s, maximum of 800,000 A / s, maximum of 700,000 A / s, maximum of 600,000 A / s, maximum of 500,000 A / s, maximum of 400,000 A / s, maximum of 300,000 A / s, maximum of 200,000 A / s, or maximum of 100,000 A / s, An actuator assembly of any of items A1 to A22, configured to generate an electrical impulse signal at at least one current rise rate.

[0166] A24. The solenoid drive circuit is, (i) at least 1 × 10 -11 , at least 1 × 10 -10 , at least 1 × 10 -9 , at least 1 × 10 -8 , at least 1 × 10 -7 , at least 1 × 10 -6 , at least 1 × 10 -5 , at least 1 × 10 -4 ; (ii) At most 1 × 10 -3 Or at most 1 × 10 -4 , An actuator assembly according to any of clauses A1 to A23, configured to have at least one duty cycle.

[0167] A25. An actuator assembly according to any of items A1 to A24, including a buffer circuit configured to selectively provide an electrical impulse signal, which is a solenoid drive circuit.

[0168] A26. The solenoid drive circuit (i) A boost converter configured to receive a power supply voltage from a power tool and boost that power supply voltage into an impulse voltage, (ii) A step-down converter configured to receive a power supply voltage from a power tool and step down the power supply voltage to an impulse voltage, An actuator assembly from any of the A1 to A25 clauses, including at least one of the following.

[0169] A27. An actuator assembly according to any of sections A1 to A26, further comprising a solenoid drive electrical conduit configured to transmit an electrical impulse signal from a solenoid drive circuit to an impulse solenoid.

[0170] A28. The solenoid-driven electrical conduit has an impulse duration. (i) No damage to the solenoid drive electrical conduit, (ii) The threshold temperature rise of the solenoid-driven electrical conduit is less than the threshold temperature rise. At least one of them has dimensions such that it repeatedly transmits an impulse current of an electrical impulse signal, An actuator assembly according to Clause A27, wherein the threshold temperature rise is optionally less than 10°C, less than 20°C, less than 30°C, less than 40°C, less than 50°C, less than 60°C, less than 70°C, less than 80°C, less than 90°C, or less than 100°C.

[0171] A29. The solenoid drive electrical conduit has a duty cycle of the solenoid drive circuit. (i) No damage to the solenoid drive electrical conduit, (ii) The threshold temperature rise of the solenoid-driven electrical conduit is less than the threshold temperature rise. At least one of them has dimensions such that it repeatedly transmits the impulse current of an electrical impulse signal, An actuator assembly according to any of the A27-A28 clauses, wherein the threshold temperature rise is optionally less than 10°C, less than 20°C, less than 30°C, less than 40°C, less than 50°C, less than 60°C, less than 70°C, less than 80°C, less than 90°C, or less than 100°C.

[0172] A30. The solenoid drive electrical conduit is an actuator assembly from any of sections A27 to A29, comprising at least one of a metal conductor, a metal wire, an insulated metal wire, a metal cable, and an insulated metal cable.

[0173] A31. An actuator assembly according to any of the terms A1 to A30, further comprising a brake assembly biasing mechanism base configured to be operably mounted to the brake assembly biasing mechanism of a brake assembly.

[0174] B1. A safety brake for power tool equipment, the safety brake is (i) A brake assembly configured to transition between a disengaged configuration that allows movement of a device and an engaged configuration that resists movement of the device, (ii) Any actuator assembly from A1 to A31, It is equipped with.

[0175] B2. The safety brake of Section B1, comprising a brake assembly configured to selectively transition between a disengaged configuration and an engaged configuration, wherein in the disengaged configuration the brake cam is separated from the device receiving area of ​​the safety brake configured to receive a device, and in the engaged configuration the brake cam extends into the device receiving area and is configured to operably engage with the device to resist the movement of the device, and the actuator assembly is configured to selectively transition the brake cam from the disengaged configuration to the engaged configuration when the impulse solenoid transitions from a non-engaged state to an activated state.

[0176] B3. The safety brake of item B2, wherein the brake cam is configured to rotate around the cam's axis of rotation, allowing for selective transitions between a disengaged configuration and an engaged configuration.

[0177] B4. A safety brake according to Section B3, wherein the mounting area is flat, or at least substantially flat, and furthermore, the cam rotation axis is parallel to or at least substantially parallel to the flat mounting area.

[0178] B5. The brake cam is a safety brake according to sections B2 to B4, including a cam biasing mechanism that biases the brake cam toward a disengaged configuration.

[0179] B6. The cam biasing mechanism includes at least one of (i) an elastic cam biasing mechanism, (ii) a cam biasing spring, and (iii) a cam biasing torsion spring, as specified in Section B5 of the safety brake.

[0180] B7. A safety brake according to any of the B2-B6 clauses, defining a device engagement surface in which a brake cam is configured to operably engage with a flat side surface of the device.

[0181] B8. The safety brake in Section B7 has a device engagement surface that is shaped to press the brake cam more and more firmly against the device when the brake cam transitions from an unengaged configuration to an engaged configuration.

[0182] B9. A safety brake according to any of the following items B7 or B8, in which the device engagement surface defines an eccentric shape.

[0183] B10. A safety brake according to any of items B7 to B9, wherein the device engagement surface defines a logarithmic spiral shape.

[0184] B11. The device engagement surface includes a cam friction material selected to increase the coefficient of friction between the device engagement surface and the device, as a safety brake according to any of sections B7 to B10.

[0185] B12. The cam friction material comprises at least one of (i) a diamond coating, (ii) an abrasive, (iii) an abrasive grain coating, (iv) a ceramic material, (v) a sintered material, or (vi) a metal alloy, as specified in Section B11 of the Safety Brake.

[0186] B13. A safety brake as defined in Sections B7 through B12, comprising a brake cam operably mounted on the remainder of the brake cam and including a device engagement surface insert that defines a device engagement surface.

[0187] B14. A safety brake of any of the types specified in sections B7 to B13, in which the device engagement surface is integrated with the brake cam.

[0188] B15. A safety brake according to any of sections B7 to B14, wherein the device engagement surface is either coated or covered with the brake cam.

[0189] B16. A safety brake according to any of the specifications B2 to B15, wherein, after transitioning from a non-engaged configuration to an engaged configuration, the brake cam remains in the engaged configuration until, optionally, the brake cam is released from the engaged configuration by the user of the power tool.

[0190] B17. The operational engagement between the tool, namely the circular saw blade, and the brake cam is the safety brake described in Section B16, which holds the brake cam in the engagement configuration.

[0191] B18. The brake assembly is a safety brake according to any of the provisions of B2 to B17, including a stopper configured to restrict the rotation of the brake cam.

[0192] B19. A safety brake according to Section B18, the stopping section includes a disengaged stopping section configured to restrict the brake cam from rotating away from the tool receiving area when the brake cam is in a disengaged configuration.

[0193] B20. A safety brake according to any of the provisions of Sections B18 to B19, wherein the stopper includes an engaged stopper configured to restrict the brake cam from rotating toward the tool receiving area when the brake cam is in an engaged configuration.

[0194] B21. (i) The stopping section is defined at least partially by the brake cam, (ii) The stopping unit is separate from the brake cam and is configured to operably engage with the brake cam in order to restrict the rotation of the brake cam. A safety brake that is at least one of the safety brakes specified in items B18 through B20.

[0195] B22. The brake assembly further includes a housing configured to operably support the brake cam and actuator assembly, and is a safety brake as defined in sections B2 to B21.

[0196] B23. The housing of the safety brake, as defined in Section B22, at least partially encloses the equipment receiving area of ​​the safety brake.

[0197] B24. The housing includes a split housing configured to be disassembled into at least two housing regions. A safety brake as described in either section B22 or B23.

[0198] B25. The brake assembly is a safety brake as defined in sections B1 to B24, further including brake pads containing pad friction material.

[0199] B26. The safety brake according to Section B25, wherein the brake pad is positioned relative to the brake cam such that the pad friction material faces the brake cam.

[0200] B27. A safety brake according to any of the B25-B26 clauses, wherein the brake pad is positioned relative to the brake cam such that the safety brake's mounting area extends at least partially between the brake pad and the brake cam.

[0201] B28. The brake pads include an adjustment mechanism configured to selectively adjust the distance between the brake pads and the brake cam, as a safety brake according to any of sections B25 to B27.

[0202] B29. A safety brake according to any of sections B25 to B28, wherein the flat side of the device is a first flat side of the device, the device includes a second flat side opposite to the first flat side, and furthermore, the pad friction material is configured to operably engage with the second flat side.

[0203] B30. A safety brake according to any of sections B25-B29, wherein the brake assembly is configured such that when the brake cam is in the engaged configuration, the device is compressed between the brake pad and the brake cam.

[0204] B31. A safety brake is any of the safety brakes described in sections B2 through B30 that do not have a pivotal connection between the brake cam and the actuator assembly.

[0205] B32. A safety brake according to any of sections B2 through B31, wherein the cam rotation axis of the brake cam is perpendicular or substantially perpendicular to the actuation axis of the actuator assembly.

[0206] B33. The brake assembly is a safety brake of any type B2 through B32, including a single brake cam.

[0207] B34. The brake assembly is configured such that the brake cam remains in the engaged configuration once it has operably engaged with the device, as is the case with any of the safety brakes in sections B2-B33.

[0208] B35. A safety brake, one of the safety brakes described in sections B1 to B34, further includes a sensor assembly configured to detect operating parameters and generate a trigger signal in response to the detection of operating parameters.

[0209] B36. The sensor assembly includes a capacitive sensor assembly configured to detect operating parameters, as described in Section B35 for the safety brake.

[0210] B37. The operating parameters include any of the safety brakes in sections B35-B36, including undesirable event parameters that indicate undesirable events to be avoided with respect to the power tool.

[0211] B38. The operating parameters include one of the safety brakes in sections B35-B37, including kickback parameters that indicate the potential for kickback of the power tool.

[0212] B39. The operating parameters include any of the safety brakes in sections B35-B38, including motion parameters that suggest undesirable motion of the power tool.

[0213] B40. The operating parameters include any of the safety brakes in items B35-B39, including proximity parameters that indicate the distance between the person and the equipment is less than the threshold distance.

[0214] B41. The sensor assembly includes a proximity sensor configured to detect proximity parameters, as specified in Section B40 for the safety brake.

[0215] B42. A brake assembly is a non-destructive brake assembly configured to selectively stop the movement of an instrument, a safety brake as defined in any of sections B1 through B41.

[0216] B43. A safety brake, one of the B1-B42 clauses, is a resettable brake assembly configured to selectively and iteratively transition between a non-engaged configuration and an engaged configuration.

[0217] B44. The brake assembly is configured to resist the movement of the device in at least one of the following ways: (i) without damage to the device, or (ii) without damage to the brake assembly, a safety brake as defined in any of sections B1 to B43.

[0218] B45. A safety brake, any of the safety brakes described in sections B1 to B44, further includes a mounting mechanism configured to operably attach at least a portion of the safety brake to a power tool.

[0219] B46. The safety brake of Section B45 includes a float mounting mechanism configured to allow the tool receiving area of ​​the safety brake to be operationally translated relative to the rest of the power tool along a float axis that is at least substantially perpendicular to the flat side of the circular saw blade, which is optionally the case.

[0220] B47. The safety brake of Section B46, wherein the float mounting mechanism includes a mounting pin, and the mounting mechanism is configured to allow the tool receiving area to be operably translated along the longitudinal axis of the mounting pin relative to other parts of the power tool.

[0221] B48. The actuator assembly is an electric actuator assembly, a safety brake as specified in section B1 through B47.

[0222] B49. The actuator assembly includes a power source configured to transmit power to the actuator assembly, and optionally the power source includes a capacitor, a safety brake according to any one of items B1 to B48.

[0223] B50. The actuator assembly includes an actuator arm configured to selectively transition the brake assembly from a disengaged configuration to an engaged configuration, a safety brake according to any one of items B1 to B49.

[0224] B51. The actuator assembly includes an electromagnet configured to selectively transition the brake assembly from a disengaged configuration to an engaged configuration, a safety brake according to any one of items B1 to B50.

[0225] B52. The actuator assembly includes a solenoid armature, and the solenoid armature is operatively engaged with the brake assembly or the brake cam of the brake assembly to transition the brake assembly or the brake cam of the brake assembly from a disengaged configuration to an engaged configuration, a safety brake according to any one of items B1 to B51.

[0226] B53. When the actuator assembly transitions the brake assembly or the brake cam from a disengaged configuration to an engaged configuration, the solenoid armature makes direct physical contact with the brake assembly or the brake cam, a safety brake according to item B52.

[0227] B54. The safety brake further includes a flexure relief structure, a safety brake according to any one of items B1 to B53.

[0228] B55. The flexure relief structure is configured to resist the tool from flexing and contacting the brake assembly when the power tool is used to cut a workpiece and the brake assembly is in a disengaged configuration, a safety brake according to item B54.

[0229] B56. A safety brake according to Section B55, wherein a deflection-relieving structure defines at least partially the equipment receiving area of ​​the safety brake.

[0230] B57. A deflection-relieving structure is a safety brake as defined in any of sections B55-B56, which includes a deflection-relieving surface configured to operatively contact the device to resist the device deflecting and contacting the brake assembly when the device deflects toward the brake assembly.

[0231] B58. The deflection relief structure includes an electrically insulating structure configured to electrically isolate the deflection relief structure from the rest of the safety brake, as described in Section B57 of the safety brake.

[0232] B59. A safety brake, any of the safety brakes described in sections B1 to B58, further comprising a reset mechanism configured to allow the user of the power tool to selectively transition the brake assembly from an engaged configuration to an unengaged configuration.

[0233] B60. The safety brake of Section B59 includes an eccentric structure configured to operationally translate and separate the brake cam of the brake assembly from the equipment receiving area of ​​the safety brake.

[0234] B61. The reset mechanism is, (i) Operationally translate the brake cam of the brake assembly to move it away from the equipment receiving area of ​​the safety brake, (ii) To move the brake pads of the brake assembly away from the equipment receiving area by operational translation, A safety brake of any of the items in sections B59 to B60, including a pressure-operated reset mechanism, configured to be at least one of the following.

[0235] B62. The brake assembly is (i) At least 0.1 millisecond (ms), at least 0.5 ms, at least 1 ms, at least 2 ms, at least 3 ms, at least 4 ms, or at least 5 ms; (ii) At most 10 ms, at most 9 ms, at most 8 ms, at most 7 ms, at most 6 ms, at most 5 ms, at most 4 ms, at most 3 ms, or at most 2 ms, and is configured to transition the brake assembly from a disengaged configuration to an engaged configuration by at least one of the above, and is a safety brake according to any one of items B1 to B61.

[0236] B63. The safety brake (I) permits current supply to the motor of the power tool when the safety brake is configured to selectively resist the movement of the tool, (ii) blocks current supply to the motor of the power tool when at least one component of the safety brake is not configured to selectively resist the movement of the tool, and further includes an interlock assembly configured as above, and is a safety brake according to any one of items B1 to B62.

[0237] B64. The interlock assembly (i) includes at least one of a sensor state detector configured to indicate the state of the sensor assembly of the safety brake, (ii) a brake assembly state detector configured to indicate the state of the brake assembly, (iii) an actuator assembly state detector configured to indicate the state of the actuator assembly, and is a safety brake according to item B63.

[0238] C1. A tool holder for holding a tool configured to perform an operation on a workpiece, a motor configured to operate the tool holder to move the tool, a safety brake according to any one of items B1 to B64, A power tool equipped with the following features.

[0239] C2. Power tools, including fixtures, as defined in Section C1.

[0240] C3. The tool is a power tool of any of the C1-C2 clauses that extends at least partially within the tool receiving area of ​​the brake assembly.

[0241] C4. Power tools are, (i) A gripping area configured to be gripped by the user of a power tool, (ii) A switch configured to be activated by the user of the power tool to start supplying current to the motor, (iii) Power cord and (iv) Battery and (v) A workpiece support configured to hold the workpiece relative to the power tool, A power tool from any of items C1 to C3, further including at least one of the following.

[0242] C5. Power tools are, (i) saw, (ii) Rotary cutting tools, (iii) fastening tools; (iv) reciprocating tools; (v) vibrating tools; (vi) woodworking tools; (vii) metalworking tools; (viii) automotive tools; A power tool from any of items C1 to C4, including at least one of the following.

[0243] C6. The equipment is, (i) bits, (ii) blade, (iii) circular saw blade, (iv) Socket, (v) Grinding wheels, (vi) chain, (vii) polishing pad, A power tool from any of items C1 to C5, including at least one of the following.

[0244] C7. The power tool is a circular saw, and the tool is a circular saw blade, one of the power tools described in items C1 to C5.

[0245] C8. When in the engagement configuration, the brake, (i) Not engaged with the teeth of the circular saw blade, (ii) Separated from the teeth of the circular saw blade, A power tool of section C7, which is at least one of the following.

[0246] C9. The brake assembly is configured to operably engage with the flat side of the circular saw blade to resist the rotation of the circular saw blade, as described in any of the power tools in sections C7-C8.

[0247] D1. The method of operating a power tool, Apply current to the motor of the power tool, The device of the power tool operates in response to the application of an electric current. During operation, the system detects operating parameters that indicate undesirable events that should be avoided with the power tool. In response to that detection, the safety brake of the power tool is switched from a disengaged configuration to an engaged configuration. This includes, When in a disengaged configuration, the safety brake allows the movement of the device. If an engagement configuration exists, the safety brake resists the movement of the device. The safety brake includes one of the actuator assemblies described in sections A1 to A3. The solenoid drive circuit is configured to generate an electrical impulse signal in response to the detection of operating parameters. Furthermore, the transition includes providing an electrical impulse signal to an impulse solenoid to transition the impulse solenoid from a non-operating state to an operating state.

[0248] D2. The transition is the method of item D1, which involves generating magnetomotive force using an impulse solenoid of the actuator assembly.

[0249] D3. The transition is one of the methods described in terms D1 to D2, which involves moving the solenoid armature through the armature's range of motion.

[0250] D4. In response to detection, this method generates a trigger signal supplied to the actuator assembly, and the transition responds to this generation, using one of the methods described in terms D1 to D3.

[0251] D5. The actuator assembly is any method described in sections D1 to D4, including any suitable structure, function and / or features of any actuator assembly described in sections A1 to A31.

[0252] D6. Safety brakes are provided by any method described in sections D1 to D5, including any suitable structure, function and / or features of any brake assembly described in sections B1 to B64.

[0253] D7. The power tool is any method of Sections D1 to D6, including any suitable structure, function and / or features of any power tool in Sections C1 to C9.

[0254] E1. The use of an impulse solenoid to selectively transition a brake assembly from a disengaged state to an engaged state in a power tool.

[0255] E2. Use of any actuator assembly in any of sections A1 to A31, any safety brake in any of sections B1 to B64, or any power tool in any of sections C1 to C9, in any manner in any of sections D1 to D7.

[0256] E3. Using any actuator assembly in any of sections A1 to A31, any safety brake in any of sections B1 to B64, or any power tool in any of sections C1 to C9, in any manner in any of sections D1 to D7. [Industrial applicability]

[0257] The power tools, safety brakes, and actuator assemblies disclosed herein are applicable to the power tool industry.

[0258] The above disclosure is considered to encompass several separate inventions, each possessing independent utility. While each of these inventions is disclosed in its preferred form, the specific embodiments disclosed and illustrated herein should not be considered restrictively, as numerous variations are possible. The subject matter of the present invention encompasses all novel and non-obvious combinations and partial combinations of the various elements, features, functions, and / or characteristics disclosed herein. Similarly, where this disclosure, the preceding paragraphs A1-E3, or any claims filed thereafter describe an "a" or "a first" element or its equivalent, such claims should be understood to include the incorporation of one or more such elements, and not to require or exclude two or more such elements.

[0259] The following claims are intended to point to one of the disclosed inventions and specifically to certain combinations and subcombinations that are novel and non-obvious. Inventions embodied in other combinations and subcombinations of features, functions, elements and / or properties may be claimed in this application or related applications through amendments to the claims or the presentation of new claims. Such amended or new claims, whether directed to a different invention or the same invention, or in a different, broader, narrower or equivalent scope to the original claims, shall be deemed to be included in the subject matter of the inventions of this disclosure.

Claims

1. An instrument holder for holding an instrument configured to perform work on a workpiece, A motor configured to operate the aforementioned device holder and cause the device to move, It is a safety brake, (i) A brake assembly configured to transition between a disengaged configuration that allows movement of the device and an engaged configuration that resists movement of the device, (ii) An actuator assembly configured to selectively provide the brake assembly with a driving force that transitions from the non-engaged configuration to the engaged configuration, Safety brakes including, A power tool equipped with, The actuator assembly includes an impulse solenoid and a solenoid drive circuit. The impulse solenoid includes an impulse coil configured to receive an electrical impulse signal and generate a magnetic field in response to the reception of the electrical impulse signal. The impulse coil is defined at least partially by a winding, The winding includes at least 10 turns of wire and at most 120 turns of wire. The wire has a diameter of at least 0.3 mm and at most 1.5 mm. The impulse solenoid is configured to selectively transition from a non-operating state to an operating state in response to the reception of the electrical impulse signal. The impulse solenoid is configured to provide the driving force during the transition from the non-operating state to the operating state, The solenoid drive circuit is configured to generate the electrical impulse signal, Furthermore, the electric power tool is configured such that the electrical impulse signal has an impulse voltage of at least 10 volts (V) and a maximum of 43 volts (V), and causes the impulse solenoid to transition from the non-operating state to the operating state with a transition time of at least 1 millisecond and a maximum of 15 milliseconds.

2. A safety brake for power tool equipment, (i) A brake assembly configured to transition between a disengaged configuration that allows movement of the device and an engaged configuration that resists movement of the device, (ii) An actuator assembly configured to selectively provide a driving force to transition the brake assembly from the disengaged configuration to the engaged configuration, Includes, The actuator assembly includes an impulse solenoid and a solenoid drive circuit. The impulse solenoid includes an impulse coil configured to receive an electrical impulse signal and generate a magnetic field in response to the reception of the electrical impulse signal. The impulse coil is defined at least partially by a winding, The winding includes at least 10 turns of wire and at most 120 turns of wire. The wire has a diameter of at least 0.3 mm and at most 1.5 mm. The impulse solenoid is configured to selectively transition from a non-operating state to an operating state in response to the reception of the electrical impulse signal. The impulse solenoid is configured to provide the driving force during the transition from the non-operating state to the operating state, The solenoid drive circuit is configured to generate the electrical impulse signal, Furthermore, the safety brake is configured such that the electrical impulse signal has an impulse voltage of at least 10 volts (V) and a maximum of 43 volts (V), and causes the impulse solenoid to transition from the non-operating state to the operating state with a transition time of at least 1 millisecond and a maximum of 15 milliseconds.

3. The safety brake according to claim 2, wherein the electrical impulse signal has an impulse duration of up to 10 milliseconds (ms), and / or the impulse duration is at least 0.25 ms.

4. The safety brake according to claim 3, wherein the solenoid drive circuit is configured to generate an electrical impulse signal having an impulse current of at least 50 amperes (A) and at most 1000 A.

5. The actuator assembly further includes a solenoid drive electrical conduit configured to transmit the electrical impulse signal from the solenoid drive circuit to the impulse solenoid, The solenoid drive electrical conduit is (i) No damage to the solenoid drive electrical conduit, (ii) The temperature rise threshold of the solenoid drive electrical conduit is less than 100°C. The safety brake according to claim 4, having dimensions such that the impulse current of the electrical impulse signal is repeatedly transmitted during the impulse duration under at least one of the following conditions.

6. The safety brake according to any one of claims 2 to 5, wherein the actuator assembly is configured to apply the driving force to the brake assembly to initiate a chain reaction of the brake assembly.

7. The safety brake according to any one of claims 2 to 6, wherein the impulse solenoid is configured to generate a magnetomotive force in response to the reception of the electrical impulse signal and to generate the driving force from the magnetomotive force, and the magnetomotive force has a magnitude of at least 5,000 ampere-turns (At) and at most 20,000 At.

8. The safety brake according to any one of claims 2 to 7, wherein the impulse coil has a time constant of at least 0.01 ms and at most 0.4 ms.

9. The safety brake according to any one of claims 2 to 8, wherein the impulse coil has a coil inductance of at least 0.01 millihenry (mH) and at most 0.44 mH.

10. The impulse solenoid includes a solenoid armature configured to move movably between a non-operating position and an operating position when the impulse solenoid transitions between the non-operating state and the operating state. The solenoid armature defines an elongated shaft, Furthermore, the safety brake according to any one of claims 2 to 9, wherein the solenoid armature is configured to translate linearly along the elongated axis when the impulse solenoid transitions between the non-operating state and the operating state.

11. The safety brake according to claim 10, wherein the solenoid armature is configured to operably engage with the brake assembly to selectively provide the driving force to the brake assembly.

12. The safety brake according to any one of claims 10 to 11, wherein the solenoid armature has an armature mass of at least 1 gram (g) and at most 30 g.

13. The safety brake according to any one of claims 10 to 12, wherein the solenoid armature defines an armature range of motion between the non-operating position and the operating position, and the armature range of motion is at least 0.5 millimeters (mm) and at most 10 mm.

14. The impulse solenoid is, (i) Driving the impulse solenoid toward a non-operating state and (ii) Transitioning the impulse solenoid from the operating state to the non-operating state after receiving the electrical impulse signal via the impulse solenoid, The safety brake according to any one of claims 2 to 13, further comprising a biasing mechanism configured to perform at least one of the following:

15. The safety brake according to any one of claims 2 to 14, wherein the solenoid drive circuit is configured to generate an electrical impulse signal with a current rise rate of at least 20,000 amperes per second (A / s) and at most 1,000,000 A / s.

16. The solenoid drive circuit comprises at least 1 × 10 －１１ At most 1 x 10 －３ A safety brake according to any one of claims 2 to 15, configured to have a duty cycle.

17. The safety brake according to any one of claims 2 to 16, wherein the solenoid drive circuit includes a buffer circuit configured to selectively provide the electrical impulse signal.

18. The solenoid drive circuit is, (i) A boost converter configured to receive a power supply voltage from the power tool and boost the power supply voltage to the impulse voltage, (ii) A step-down converter configured to receive the power supply voltage from the power tool and step down the power supply voltage to the impulse voltage, A safety brake according to any one of claims 2 to 17, comprising at least one of the following.

19. The safety brake according to any one of claims 2 to 18, further comprising a reset mechanism configured to allow the user to selectively transition the brake assembly from the engaged configuration to the disengaged configuration.

20. The brake assembly includes a brake cam configured to selectively transition between the disengaged configuration and the engaged configuration. In the non-engaged configuration, the brake cam is separated from the device receiving area of ​​the safety brake configured to receive the device, and in the engaged configuration, the brake cam extends into the device receiving area and is configured to operably engage with the device and resist the movement of the device. The safety brake according to any one of claims 2 to 19, wherein the actuator assembly is configured to selectively transition the brake cam from the non-engaged configuration to the engaged configuration when the impulse solenoid transitions from the non-operated state to the operated state.

21. The brake cam is configured to rotate around the cam's axis of rotation, and to selectively transition between the disengaged configuration and the engaged configuration. The aforementioned fixture receiving area is at least substantially flat, Furthermore, the safety brake according to claim 20, wherein the axis of rotation of the cam is at least substantially parallel to the flat device receiving area.

22. The safety brake according to claim 21, wherein the axis of rotation of the brake cam is substantially perpendicular to the operating axis of the actuator assembly.

23. The safety brake according to any one of claims 20 to 22, wherein the brake assembly further includes a brake pad comprising a pad friction material, the brake pad being positioned relative to the brake cam such that the pad friction material faces the brake cam.

24. The safety brake according to claim 23, wherein the brake pad is positioned relative to the brake cam such that the device receiving area of ​​the safety brake extends at least partially between the brake pad and the brake cam.

25. The safety brake according to any one of claims 23 to 24, wherein the brake assembly is configured such that when the brake cam is in the engagement configuration, the device is compressed between the brake pad and the brake cam.

26. The safety brake according to any one of claims 20 to 25, wherein the safety brake does not have a pivot connection between the brake cam and the actuator assembly.

27. The brake assembly comprises a single brake cam, according to any one of claims 20 to 26.

28. The safety brake according to any one of claims 20 to 27, wherein the brake assembly is a locking brake assembly configured such that when the brake cam operably engages with the device, it remains in the engagement configuration.

29. The safety brake according to any one of claims 2 to 28, further comprising a sensor assembly configured to detect operating parameters and generate a trigger signal in response to the detection of the operating parameters.

30. The aforementioned brake assembly is (i) No damage to the instrument, (ii) No damage to the brake assembly, A safety brake according to any one of claims 2 to 29, configured to resist the movement of the device under at least one of the following conditions.

31. The safety brake according to any one of claims 2 to 30, wherein the brake assembly is a resettable brake assembly configured to selectively and repeatedly transition between the disengaged configuration and the engaged configuration.

32. The safety brake according to any one of claims 2 to 31, wherein the brake assembly is configured to transition from a disengaged configuration to an engaged configuration in a maximum of 10 ms.

33. An instrument holder for holding an instrument configured to perform work on a workpiece, A motor configured to operate the aforementioned device holder and cause the device to move, A safety brake according to any one of claims 2 to 32, Power tools equipped with [specific features / features].

34. The power tool according to claim 1 or claim 33, wherein the power tool is a circular saw, and the device is a circular saw blade.

35. When the engagement configuration is in place, the brake assembly is (i) Not engaged with the teeth of the circular saw blade, (ii) Distance from the teeth of the circular saw blade, The power tool according to claim 34, which is at least one of the following.

36. The power tool according to any one of claims 34 to 35, wherein the brake assembly is configured to engage with the flat side surface of the circular saw blade to resist the rotation of the circular saw blade.

37. The method of operating a power tool, The aforementioned method, Current is applied to the motor of the aforementioned power tool, In response to the application of electric current, the device of the electric tool is operated. During operation, the system detects operating parameters that indicate undesirable events that should be avoided by the power tool. In response to the detection, the safety brake of the power tool is switched from a disengaged configuration that allows the operation of the tool to an engaged configuration that resists the operation of the tool. This includes, The safety brake includes an actuator assembly configured to provide the driving force for the transition, Furthermore, the actuator assembly includes: (i) Impulse solenoid and (ii) Solenoid drive circuit and It includes, The impulse solenoid includes an impulse coil configured to receive an electrical impulse signal and generate a magnetic field in response to the reception of the electrical impulse signal. The impulse coil is defined at least partially by a winding, The winding includes at least 10 turns of wire and at most 120 turns of wire. The wire has a diameter of at least 0.3 mm and at most 1.5 mm. The impulse solenoid is configured to selectively transition from a non-operating state to an operating state in response to the reception of the electrical impulse signal. The impulse solenoid is configured to provide the driving force when transitioning from the non-operating state to the operating state, The solenoid drive circuit is configured to generate the electrical impulse signal in response to the detection of the operating parameter, The electrical impulse signal is configured to have an impulse voltage of at least 10 volts (V) and a maximum of 43 volts, an impulse duration of at least 0.25 milliseconds and a maximum of 10 milliseconds, and to cause the impulse solenoid to transition from the non-operating state to the operating state with a transition time of at least 1 millisecond and a maximum of 15 milliseconds. Furthermore, the method includes providing the electrical impulse signal to the impulse solenoid to cause the impulse solenoid to transition from a non-operating state to an operating state.

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