Electric tool

Abstract

A power tool includes a housing, a motor at least partially positioned within the housing, a driver blade extending along a drive axis, and a cam assembly including a cam configured to rotate about a rotation axis to move the driver blade. The cam includes a target rotating with the cam. The sensor is configured to detect the target when the target is at a predetermined rotational position of the cam. The controller is connected to the motor and the sensor. The controller is configured to receive a signal from the sensor indicating that the target is in a predetermined rotational position of the cam, compare the motor parameter to a threshold value, and initiate a speed ramp in response to the target being in the predetermined rotational position of the cam and the motor parameter being greater than or equal to the threshold value.

Description

[0001] Related Applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 520,700, filed Aug. 21, 2023, the entire content of which is hereby incorporated by reference into this application. Technical Field

[0003] The specific embodiments described herein relate to power tools. Background Art

[0004] When a power tool is determined to be in a fault condition, the motor of the power tool needs to be disconnected, but at this time the speed of the motor drops directly, and the power tool (e.g., during a heavy-duty cycle) is prone to overshoot of the drive blade. When the power tool of the present utility model is determined to be in a fault condition, the controller gradually ramps down the speed of the motor. After reaching the ramp-down speed, the motor can be braked by the controller, and the power tool can limit the amount of energy of the power tool (e.g., during a heavy-duty cycle), preventing overshoot of the drive blade. Summary of the Utility Model

[0005] The specific embodiments described herein relate to power tools, such as fastener drivers implementing closed-loop speed control. The closed-loop speed control is used to control the speed at which the motor rotates during, for example, the heavy-duty cycle of a fastener driver.

[0006] The specific embodiments described herein include a housing, a motor, a storage chamber cylinder, an inner cylinder, a drive blade, and a cam assembly. The housing includes a drive unit support portion, a cylinder support portion, and a handle portion. The motor is at least partially positioned within the drive unit support portion. The storage chamber cylinder is at least partially positioned within the cylinder support portion. The inner cylinder has an annular inner wall defining a drive axis, and at least a portion of the annular inner wall is within the storage chamber cylinder. The drive blade extends along the drive axis. The cam assembly includes a cam configured to rotate about a rotation axis to move the drive blade. The cam includes an object that rotates with the cam. A sensor is configured to detect the object when the object is at a predetermined rotational position of the cam. A controller is connected to the motor and the sensor. The controller is configured to receive a signal from the sensor indicating that the object is at the predetermined rotational position of the cam, compare motor parameters with a threshold, and initiate a ramp down in speed in response to the object being at the predetermined rotational position of the cam and the motor parameters being greater than or equal to the threshold.

[0007] In some aspects, the controller is configured to not initiate the speed ramp-down in response to the object being at a predetermined rotational position of the cam and the motor parameter being less than the threshold.

[0008] In some aspects, the object includes a magnet.

[0009] In some aspects, the sensor is a Hall effect sensor configured to detect the position of the magnet.

[0010] In some aspects, the Hall effect sensor is configured to detect the position of the magnet when the magnet is at a predetermined rotational position of the cam.

[0011] In some aspects, the speed ramp-down is a linear speed ramp-down.

[0012] In some aspects, the sensor includes an inductive sensor.

[0013] In some aspects, the inductive sensor is configured to detect the position of the object when the object is at a predetermined rotational position of the cam.

[0014] In some aspects, the speed ramp-down is a linear speed ramp-down.

[0015] In some aspects, the motor parameter is the speed of the motor, and the threshold is the speed threshold of the motor.

[0016] The method according to the present utility model relates to a method of operating a power tool. The power tool includes a drive blade extending along a drive axis and a cam assembly, the cam assembly including a cam configured to rotate about a rotational axis to move the drive blade. The cam includes an object that rotates with the cam. The method includes receiving, at a controller of the power tool, a signal from a sensor indicating that the object is at a predetermined rotational position of the cam, comparing a motor parameter with a threshold, and initiating a speed ramp-down in response to the object being at the predetermined rotational position of the cam and the motor parameter being greater than or equal to the threshold.

[0017] In some aspects, the object includes a magnet.

[0018] In some aspects, the sensor is a Hall effect sensor, and the method further includes detecting the position of the magnet through the Hall effect sensor.

[0019] In some aspects, the method further includes detecting the position of the magnet through the Hall effect sensor when the magnet is at a predetermined rotational position of the cam.

[0020] In some aspects, the speed ramp-down is a linear speed ramp-down.

[0021] In some aspects, the sensor includes an inductive sensor.

[0022] In some aspects, the method further includes using the inductive sensor to detect the target when the target is at a predetermined rotational position of the cam.

[0023] In some aspects, the speed ramp-down is a linear speed ramp-down.

[0024] In some aspects, the motor parameter is the speed of the motor, and the threshold is the speed threshold of the motor.

[0025] The power tool according to the present utility model includes a housing, a motor at least partially positioned within the housing, a drive blade extending along a drive axis, and a cam assembly including a cam configured to rotate about a rotational axis to move the drive blade. The cam includes a target that rotates with the cam. A sensor is configured to detect the target when the target is at a predetermined rotational position of the cam. A controller is connected to the motor and the sensor. The controller is configured to receive a signal from the sensor indicating that the target is at the predetermined rotational position of the cam, compare a motor parameter with a threshold, and initiate a speed ramp-down in response to the target being at the predetermined rotational position of the cam and the motor parameter being greater than or equal to the threshold.

[0026] Before explaining any specific embodiments in detail, it should be understood that the application of the specific embodiments is not limited to the details of the configuration and arrangement of the component parts set forth in the following description or shown in the drawings. These specific embodiments can be implemented or realized in various ways. In addition, it should be understood that the wording and terminology used in this application are for the purpose of description and should not be regarded as restrictive. The use of "including", "comprising", or "having" and their variants means covering the items listed hereinafter and their equivalents as well as additional items. Unless otherwise specified or limited, the terms "mounted", "connected", "supported", and "coupled" and their variants are used in a broad sense and include direct and indirect mounting, connection, support, and coupling.

[0027] Unless the context of their use clearly indicates otherwise, the articles "a", "an", and "the" should not be construed to mean "one" or "only one". Instead, these words should be construed to mean "at least one" or "one or more". Similarly, when the terms "the" or "said" are used to refer to a noun previously introduced by the indefinite article "a" or "an", "the" and "said" mean "at least one" or "one or more", unless the context of their use clearly indicates otherwise.

[0028] In addition, it should be understood that the specific embodiments may include hardware, software, and electronic components or modules. For the purpose of discussion, these components may be illustrated and described as if most components were implemented only in hardware. However, those of ordinary skill in the art, upon reading this detailed description, will recognize that in at least one specific embodiment, the electronic aspects may be implemented in software (e.g., stored on a non-transitory computer-readable medium) executable by one or more processing units, such as microprocessors and / or application specific integrated circuits ("ASICs"). Therefore, it should be noted that the specific embodiments may be implemented using a plurality of hardware- and software-based devices and a plurality of different structural components. For example, "servers", "computing devices", "controllers", "processors", etc. may include one or more processing units, one or more computer-readable medium modules, one or more input / output interfaces, and various connectors connecting the components (e.g., a system bus).

[0029] Related terms, such as "about", "approximately", "substantially", etc., when used in connection with a quantity or condition, will be understood by those of ordinary skill in the art to include the recited value and to have the meaning ascribed by the context (e.g., the term includes at least the degree of error associated with the measurement accuracy, the tolerances associated with a particular value [e.g., manufacturing, assembly, use, etc.], etc.). Such terms should also be considered to disclose a range defined by the absolute values of two endpoints. For example, the phrase "from about 2 to about 4" also discloses the range "from 2 to 4". Related terms may refer to plus or minus a percentage of the indicated value (e.g., 1%, 5%, 10%).

[0030] It should be understood that although some of the figures illustrate hardware and software located within a particular device, these illustrations are for illustrative purposes only. The functions performed by one component described in this application may be performed by multiple components in a distributed manner. Similarly, the functions performed by multiple components may be combined and performed by a single component. In some specific embodiments, the illustrated component assemblies may be combined or divided into separate software, firmware, and / or hardware. For example, the logic and processing may be distributed among multiple electronic processors rather than being located within and performed by a single electronic processor. Regardless of how they are combined or divided, the hardware and software components may be located on the same computing device or may be distributed among different computing devices connected by one or more networks or other suitable communication links. Similarly, the components described as performing a particular function may also perform additional functions not described in this application. For example, a device or structure "configured" in a certain way is at least configured in this way, but may also be configured in ways not explicitly listed.

[0031] Thus, in a claim, if an apparatus, method, or system is claimed, for example, including a controller, control unit, electronic processor, computing device, logic element, module, memory module, communication channel, or network, or other elements configured in a certain way, for example, to perform multiple functions, then the claim or claim element should be construed to refer to one or more such elements, where any one of the one or more elements is configured as claimed, for example, to cause any one or more of the multiple functions to have the multiple functions, such that the one or more elements, as a kit, jointly perform multiple functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1A is a perspective view of a power tool according to a specific embodiment of the present invention.

[0033] Figure 1B is Figure 1A Another perspective view of the power tool, which further shows the depth of the drive adjustment assembly.

[0034] Figure 1C is Figure 1A a side view of the power tool.

[0035] Figure 2 is Figure 1A Another perspective view of the power tool, where a part of the power tool has been removed.

[0036] Figure 3 is Figure 1A a cross-sectional view of the power tool taken along line 3-3 of Figure 1B

[0037] Figure 4A is Figure 1A a schematic view of the power tool, which shows the drive blade in the driven or bottom-dead-center position.

[0038] Figure 4B is Figure 1A a schematic view of the power tool, which shows the drive blade in the top-dead-center position.

[0039] Figure 5 shows the control system of the power tool according to some specific embodiments of Figure 1A

[0040] Figure 6 shows the rotation of the cam of the power tool according to some specific embodiments of Figure 1A

[0041] ​​​Figure 7 is a side view of a portion of a power tool with a portion removed to show a lifting assembly Figure 1A

[0042] Figure 8 is Figure 1A a top view of a portion of a power tool that shows a lifter position sensor assembly coupled to a lifting assembly

[0043] Figure 9 shows a closed-loop speed control of a motor of a power tool according to some embodiments Figure 1A

[0044] Figure 10 is a process for controlling a Figure 1A power tool Embodiments

[0045] See Figure 1A and 1B , a power tool 10, such as a gas spring-driven fastener driver, can be used to drive fasteners (e.g., nails, staples, staples, etc.) placed in a storage magazine 14 into a workpiece. The power tool 10 includes an inner cylinder 18 and a movable piston 22 positioned within the inner cylinder 18 ( Figure 3 - 4B ). See Figure 3 - 4B , the power tool 10 further includes a driver blade 26 attached to and movable with the piston 22. The power tool 10 does not require an external air pressure source, but instead includes a pressurized gas external storage chamber cylinder 30 in fluid communication with the inner cylinder 18. In the illustrated embodiment, the inner cylinder 18 and the movable piston are positioned within the storage chamber cylinder 30. The power tool 10 further includes an inflation valve (not shown) coupled to the storage chamber cylinder 30. When connected to a compressed gas source, the inflation valve allows the storage chamber cylinder 30 to be refilled with compressed gas if any leakage has occurred previously. The inflation valve can be configured as, for example, a Schrader valve.

[0046] See Figure 4A - 4B , the inner cylinder 18 and the driver blade 26 define a drive axis 38. During a drive cycle, the driver blade 26 and the piston can move between a top dead center (TDC) position ( Figure 4B ) and a driven or bottom dead center (BDC) position ( Figure 4A ). See Figure 2 and 3 , the power tool 10 further includes a lifting assembly 42 ( Figure 2 ), which has a lifter 44 driven by a motor 46 ( Figure 2 ) and moves the driver blade 26 from a driven position to a TDC position. As Figure 2 and​​3 As shown, in the illustrated embodiment, the inner cylinder 18 is partially defined by an inner frame 48 (such as an inner housing). Specifically, the inner frame 48 is coupled to the inner cylinder 18. Further referring to Figure 2 and 3 , the inner frame 48 also at least partially supports the lifting assembly 42 and the motor 46. The inner frame 48 is constructed of a material stronger than plastic - such as metal.

[0047] In operation, the lifting assembly 42 drives the piston 22 and the driver blade 26 toward the TDC position by energizing the motor 46. As the piston 22 and the driver blade 26 are driven toward the TDC position, the gas above the piston 22 and the gas within the storage chamber cylinder 30 are compressed. Before reaching the TDC position, the motor 46 is deactivated and the piston 22 and the driver blade 26 are held in a seated position between the TDC and the BDC or the driven position until released by the user activating the trigger 49 ( Figure 1A ). When released, the compressed gas above the piston 22 and within the storage chamber cylinder 30 drives the piston 22 and the driver blade 26 to the driven position, thereby driving the fastener into the workpiece. The illustrated power tool 10 thus operates the lifting assembly 42 and the piston 22 according to the gas spring principle to further compress the gas within the inner cylinder 18 and the storage chamber cylinder 30.

[0048] Referring to Figure 3 - 4B , the storage chamber cylinder 30 surrounds the inner cylinder 18. The inner cylinder 18 has an annular inner wall 50 configured to guide the piston 22 and the driver blade along the drive axis 38 to compress the gas within the storage chamber cylinder 30. As Figure 2 - 3 shown, the inner frame 48 is coupled to the annular inner wall 50 of the inner cylinder 18. The storage chamber cylinder 30 has an annular outer wall 54 that circumferentially surrounds the annular inner wall 50. Thus, the inner cylinder 18 is configured to be axially fixed to the storage chamber cylinder 30.

[0049] Referring to Figure 3 - 4B , the power tool 10 includes a buffer 60 supported by the inner frame 48 and positioned below the piston 22 for blocking the piston 22 and absorbing the impact energy from the piston 22 at the driven position ( Figure 4B ). The buffer 60 is configured to evenly distribute the impact force of the piston 22 over the entire buffer 60 as the piston 22 rapidly decelerates once it reaches the driven position (i.e., the bottom dead center position).

[0050] Referring to Figure 1A , the power tool 10 includes a housing 80, a drive unit support portion 88, a handle portion 91, and a battery support portion 93. The housing 80 has a cylinder support portion 84, and the storage chamber cylinder 30 is at least partially positioned within the cylinder support portion 84. The motor 46 and the transmission 92 ( Figure 2) is at least partially positioned within the drive unit support portion 88. Additionally, in the illustrated embodiment, the cylinder support portion 84 and the battery support portion 93 are spaced from each other and extend between the drive unit support portion 88 and the handle portion 91. Accordingly, the drive unit support portion 88 and the handle portion 91 are also spaced from each other. As Figure 1C shown, the drive unit support portion 88 extends along a drive unit support axis 88' that intersects the drive axis 38. The battery support portion 93 has an angled surface 93' positioned at an angle that is neither parallel nor perpendicular to the drive unit support axis 88'. Additionally, the battery attachment interface 94 defines an intersection axis 94' that is neither parallel nor perpendicular to the drive axis 38 or the drive unit support axis 88'. In the illustrated embodiment, the cylinder support portion 84, the drive unit support portion 88, the handle portion 91, and the battery support portion 93 are integrally formed as a single piece (e.g., using a casting or molding process, depending on the materials used). Additionally, the housing 80 is formed from a plastic material. The inner frame 48 is thus made of a material (e.g., metal) that is harder, stronger, and more robust than the material (e.g., plastic) used to form the housing 80.

[0051] The actuator 92 raises the driver blade 26 from the driven position to the ready position. Refer to Figure 1A - 3 , the motor 46 is positioned within the drive unit support portion 88 and is configured to provide torque to the actuator 92 upon activation. The battery pack 90 is received and supported by the battery pack attachment interface of the handle portion 91. The battery pack 90 can be electrically connected to the motor 46 to supply power to the motor 46. In an alternative embodiment, the driver can be powered by an alternative power source such as an alternating voltage input (i.e., from a wall outlet) or through an alternative direct current voltage input (e.g., an AC / DC converter). Refer to Figure 2 , the actuator 92 provides torque from the motor 46 to the lifter 44.

[0052] The operation of the firing cycle of the power tool 10 is shown and explained below. Refer to Figure 4B , before the start of the firing cycle, the driver blade 26 is held in the ready position while the piston 22 is near top dead center within the inner cylinder 18. Once the trigger 49 is pulled to start the firing cycle, the motor 46 is activated to rotate the lifter 44 in a counterclockwise direction from the Figure 2 reference frame, thereby translating the driver blade 26 upward to the TDC position of the driver blade 26. Thereafter, the piston 22 and the driver blade 26 are moved toward the driven position by the expanding gas within the inner cylinder 18 and the storage chamber cylinder 30 ( Figure 4A)Push downward. As the driver blade 26 translates toward the driven position, the motor 46 remains activated to continue rotating the lifter 44 counterclockwise. Once the fastener is driven into the workpiece, the piston 22 impacts the buffer 60 to rapidly decelerate the piston 22 and the driver blade, eventually stopping the piston 22 at the driven or bottom dead center position. Shortly after the driver blade 26 reaches the driven position, the lifter 44 continues to rotate counterclockwise to lift the driver blade 26 and the piston 22 toward the ready position.

[0053] Although Figure 1A - 4B the power tool 10 is shown as a straight nailer, the power tool 10 can alternatively be various different types of power fastener tools. For example, in some specific embodiments, the power tool 10 is a duplex nailer, a roofing nailer, a framing nailer, a connector nailer, a brad nailer, a pin nailer, a fencing stapler, a crown stapler, a cable stapler, etc. Each fastening power tool is configured to be powered by a power source such as the battery pack 90.

[0054] Figure 5 An example control system 500 for the power tool 10 is shown. The control system 500 includes a controller 504. The controller 504 can be electrically and / or communicatively connected to various modules or components of the nailer. For example, the illustrated controller 504 is electrically connected to the motor 508 (e.g., motor 46), the battery pack interface 512, the trigger switcher 516, one or more sensors 524 (e.g., current sensors, position sensors, etc.) and the temperature sensor 528, the wireless communication controller 538, one or more indicators 532, one or more user input modules 536, the power input module 540, and the door controller 544 (connected to the inverter 548). The motor 508 includes a rotor, a stator, and a shaft that rotates about a longitudinal axis.

[0055] The controller 504 includes a combination of software and hardware that can be used to control, in particular, the operation of the power tool 10, monitor the operation of the power tool 10, activate one or more indicators 532 (such as LEDs), and so on. The door controller 544 is configured to control the inverter 548 to convert a DC power supply into a phase signal for powering the phases of the motor 508. The current sensor 524 is configured to sense, for example, the current between the inverter 548 and the motor 508. The temperature sensor 528 is configured to sense, for example, the temperature of the inverter 548. In some embodiments, the temperature sensor 528 is configured to sense, for example, the temperature of the rechargeable battery pack 90.

[0056] The controller 504 includes a plurality of electrical and electronic components that provide power, operation control, and protection to components and modules within the controller 504 and / or the power tool 10. For example, the controller 504 particularly includes a processing unit 552 (such as, for example, a microprocessor, a microcontroller, an electronic processor, an electronic controller, or another suitable programmable device), a memory 556, an input unit 560, and an output unit 564. The processing unit 552 particularly includes a control unit 568, an arithmetic logic unit (“ALU”) 572, and a plurality of registers 576 (such as a set of registers as Figure 5 shown), and is implemented using a known computer architecture (such as, for example, a modified Harvard architecture, a von Neumann architecture, etc.). The processing unit 552, the memory 556, the input unit 560, the output unit 564, and various modules or circuits connected to the controller 504 are connected by one or more control and / or data buses (such as, for example, the common bus 580). For illustrative purposes, the control and / or data bus is shown generally in Figure 5 . Given the inventive concept described in the present utility model, those skilled in the art will know to use one or more control and / or data buses for the interconnection and communication between various modules, circuits, and components.

[0057] The memory 556 is a non-transitory computer-readable medium and includes, for example, a program storage area and a data storage area. The program storage area and the data storage area may include a combination of different types of memories, such as ROM, RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, hard disk, SD card, or other suitable magnetic, optical, physical, or electronic storage devices. The processing unit 552 is connected to the memory 556 and executes software instructions that can be stored in the RAM of the memory 556 (e.g., during execution), the ROM of the memory 556 (e.g., on a substantially permanent basis), or another non-transitory computer-readable medium such as another memory or disk. The software included in the implementation of the power tool 100 may be stored in the memory 556 of the controller 504. The software includes, for example, firmware, one or more application programs, program data, filters, rules, one or more program modules, and other executable instructions. The controller 504 is configured to retrieve and execute instructions related to the control processes and methods described in the present invention from the memory 556. In other configurations, the controller 504 includes additional, fewer, or different components.

[0058] The battery pack interface 512 includes a combination of mechanical components (e.g., rails, grooves, latches, etc.) and electrical components (e.g., one or more terminals) that are configured and operable to interface the power tool 10 with a battery pack (e.g., mechanically, electrically, and communicatively connect). For example, the power supplied by the battery pack to the nail gun is provided to the power input module 540 through the battery pack interface 512. The power input module 540 includes a combination of active and passive components to condition or control the power received from the battery pack before providing power to the controller 504. The battery pack interface 512 also powers an inverter 548 switched by a switching FET to selectively power the motor 508. The battery pack interface 512 also includes, for example, a communication line 584 for providing a communication line or link between the controller 504 and the battery pack.

[0059] Indicator 532 includes, for example, one or more light emitting diodes (“LEDs”). Indicator 532 can be configured to display the condition of power tool 10 or information associated with power tool 10. For example, indicator 532 is configured to indicate the measured electrical characteristics of power tool 10, the status of the device, etc. One or more user input modules 536 are operatively coupled to controller 504 to, for example, select a forward or reverse operating mode, torque and / or speed settings of power tool 10 (e.g., using a torque and / or speed switch), etc. In some embodiments, one or more user input modules 536 can include a combination of digital or analog input or output devices required to achieve a desired nail gun operating level, such as one or more knobs, one or more dials, one or more switches, one or more buttons, etc. In some embodiments, one or more user input modules 536 can wirelessly receive signals from a device external to power tool 10 (e.g., the user's mobile phone).

[0060] Controller 504 can be configured to determine whether a fault condition exists in power tool 10 and generate one or more control signals associated with the fault condition. For example, controller 504 can calculate or include in memory 556 predetermined operating thresholds and operating limits for power tool 10. For example, when controller 504 detects or predicts a potential thermal failure (e.g., of the FET, motor 508, etc.), the power supplied to motor 508 can be limited or interrupted until the likelihood of thermal failure is reduced. If controller 504 detects one or more such fault conditions of the nail gun or determines that the fault condition of power tool 10 no longer exists, controller 504 can be configured to provide information and / or control signals to another component of power tool 10 (e.g., battery pack interface 512, indicator 532, etc.). The signal can be configured to, for example, trip or open a high impedance trace of the nail gun, reset a switch, etc.

[0061] The controller 504 may be configured to determine the state of charge (“SOC”) of the rechargeable battery pack 90. The controller 504 may also be configured to receive signals from a monitoring circuit (such as including the sensor 524, etc.), the monitoring circuit being configured to sense the SOC level or voltage value of the battery cells of the rechargeable battery pack 90 and send the voltage readings to the controller 504. The voltage level of the battery cells may be determined, for example, by measuring the total open circuit voltage of the battery cells or by summing the voltage measurement results of each battery cell. In some specific embodiments, the monitoring circuit is additionally configured to sense the discharge current of the battery cells (such as using a current sensor) and / or the temperature of the rechargeable battery pack 90 (such as using a temperature sensor) and send the sensed current and / or temperature readings to the controller 504. The monitoring circuit is further configured to receive commands from the controller 504 during the operation of the power tool 10. In some specific embodiments, the SOC, sensed current, and / or sensed temperature of the rechargeable battery pack 90 are determined by the battery pack 90 and transmitted to the power tool 10.

[0062] Figure 6 The cam assembly 600 (such as a part of the lifting assembly 42) is shown. The cam assembly includes a cam 605 that rotates about a rotation axis 610. The cam 605 includes an object 615 (such as a magnet) that rotates with the cam 605. The magnetic sensor 620 (such as a Hall effect sensor) is configured to detect the object 615 as the cam 605 rotates about the rotation axis 610. In some specific embodiments, the magnetic sensor 620 is configured to detect when the cam 605 has rotated to a predetermined position (such as three-quarter cam rotation position). The magnetic sensor 620 is configured to output a signal indicating the position of the cam 605 that is received by the controller 504. In some specific embodiments, sensors other than the magnetic sensor may be used to detect the position of the cam 605. For example, an inductive sensor 700 ( Figure 7 ) may be used to detect the position of the cam 605, which will be described in detail below in conjunction with Figure 7 and 8 . The use of the inductive sensor 700 enables the absolute position detection and control of the cam 605. The function of the absolute position detection is to reduce the firing time of the next firing sequence and reduce the number of rotation degrees required to brake the motor 508.

[0063] The electric motor 508 is configured to operate at maximum speed or unrestricted (e.g., 100% PWM signal) between the start of the heavy load period and a predetermined position of the cam. When the controller 504 determines that the cam 605 has rotated to the predetermined position, the controller 504 is configured to control the rotational speed of the electric motor 508 (e.g., reduce the PWM signal). For example, between the predetermined position of the cam 605 and the end of rotation (e.g., the initial window), the controller 504 is configured to use closed-loop speed control to control the speed of the electric motor 508. Using closed-loop speed control, the controller 504 is configured to gradually reduce the speed of the electric motor between the predetermined position of the cam 605 and the end of rotation (e.g., linearly, near linearly, etc.).

[0064] Figure 7 Yes Figure 1A An enlarged side view of a portion of a power tool that shows the lift assembly 42. The power tool 10 includes an inductive sensor 700 coupled to the inner frame 48 through an inductive sensor housing 705 and a sensor target 710 coupled for co-rotation with the lifter 44. The inductive sensor 700 is electrically connected to the controller 504. The sensor target 710 is configured to be sensed or detected by the inductive sensor 700. The inductive sensor 700 can be coupled to any part of the inductive sensor housing 705 such that the sensor target 710 can be detected. The inductive sensor 700 and the sensor target 710 together define a lifter position sensing assembly 725. The lifter position sensing assembly 725 is configured to detect the angular position of the lifter 44 and the controller 504 is configured to stop the electric motor 508 in response to detecting that the angular position of the lifter 44 has reached a predetermined position. As the lifter 44 rotates, the pin 715 and the roller 720 sequentially engage lift teeth formed on the drive blade 26 (see Figure 3 ) to return the drive blade 26 along the drive axis 38 from the BDC position to the TDC position.

[0065] Figure 8 Yes Figure 1ATop view of a portion of a power tool, which shows a lift position sensing assembly 725 coupled to a lift assembly 42. An inductive sensor 700 is coupled to the frame 48 at a position below the lift 44 through an inductive sensor housing 705. In other words, the inductive sensor 700 is positioned between the lift 44 and the motor 508. The sensor target 710 is separated from the lift 44 and made of a material different from that of the lift 44 (e.g., to reduce weight). In other words, the lift 44 is formed of a first material, while the sensor target 710 is formed of a second material (e.g., a lighter material) different from the first material. In other specific embodiments, the sensor target 710 may be integrally formed with the lift (e.g., a coating on the lift 44, etc.). Additionally, in some specific embodiments, the inductive sensor 700 may be located above the lift 44 and on the side of the lift 44 opposite to the motor 508. The combination of the inductive sensor 700 and the sensor target 710, also referred to as the lift position sensing assembly 725, allows the controller 504 to detect the position of the lift 44 and can be used to detect anomalies during the operation of the fastener driver 210.

[0066] Figure 9 The closed-loop speed control of the motor 508 is shown in a graph of the speed 905 of the motor 508. The speed ramp-down starts at a predetermined position (e.g., three-quarters of the cam rotation position) and gradually ramps down the speed of the motor 508. The speed of the motor 508 can be determined by the controller 504 based on, for example, the transition of a Hall effect sensor that detects the rotational position of the rotor of the motor 508. The speed 905 of the motor 508 eventually reaches the ramp-down speed (e.g., 8000 RPM). After reaching the ramp-down speed, the motor 508 can be braked, for example, by the controller 504.

[0067] The closed-loop speed control of the motor 508 enables the power tool 10 to limit the amount of energy of the power tool 10 (e.g., during heavy-duty cycles). A particular advantage of such control is to limit power when the impedance of the battery pack 90 is lower than that of another existing battery pack. Additionally, by controlling the speed as described above, overshoot of the drive blade 12 can be prevented.

[0068] Figure 10 A process 1000 for a power tool 10 is shown. The implementation of the process 1000 enables the controller 504 to be configured to determine when to implement as described above in connection with Figure 6 - 9The speed ramp-down described above. Process 1000 begins (step 1005) by operating (e.g., starting a firing sequence) the power tool 10. The controller 504 then determines whether to implement a full stop condition (step 1010). For example, after the firing sequence when the drive blade 26 is to be driven back to the TDC position, there is a full stop condition when the motor stops at the TDC position. If there is no full stop condition, process 1000 returns to step 1005. If a full stop condition is to be implemented, the process continues to step 1015 and motor parameters are determined. The motor parameters can be the speed of the motor 508 (e.g., revolutions per minute of the motor 508). In some embodiments, motor parameters other than or including speed can be used, such as motor current, motor power, motor torque, motor voltage, etc. In some embodiments, the motor parameters are continuously monitored so that the controller 504 knows the current value of the motor parameters at any time.

[0069] The controller 504 then compares the motor parameters with a threshold (step 1020). For example, when the motor parameter is the motor speed, the threshold is a speed value (e.g., revolutions per minute). If the motor parameter is less than the threshold, then the speed ramp-down is not started (step 1025) and the motor 508 is stopped (step 1030) without a speed ramp-down. If the motor parameter is greater than or equal to the threshold in step 1020, then the speed ramp-down is started as described above (step 1035). After the speed ramp-down, the motor then stops (step 1030).

[0070] Representative features

[0071] The following items illustrate representative features, which may exist alone or may be combined in any manner with one or more features disclosed in the text of the patent specification and / or the drawings.

[0072] Article 1: A power tool, comprising a housing, a motor, a storage chamber cylinder, an inner cylinder, a drive blade, a cam assembly, a sensor, and a controller. The housing includes a drive unit support portion, a cylinder support portion, and a handle portion. The motor is at least partially positioned within the drive unit support portion. The storage chamber cylinder is at least partially positioned within the cylinder support portion. The inner cylinder has an annular inner wall defining a drive axis, and at least a portion of the annular inner wall is within the storage chamber cylinder. The drive blade extends along the drive axis. The cam assembly includes a cam configured to rotate about a rotation axis to move the drive blade. The cam includes an object that rotates with the cam. The sensor is configured to detect the object when the object is at a predetermined rotational position of the cam. The controller is connected to the motor and the sensor, and the controller is configured to: receive a signal from the sensor indicating that the object is at the predetermined rotational position of the cam, compare a motor parameter with a threshold, and initiate a speed ramp-down in response to the object being at the predetermined rotational position of the cam and the motor parameter being greater than or equal to the threshold.

[0073] Article 2: The power tool according to Article 1, wherein the controller is configured not to initiate the speed ramp-down in response to the object being at the predetermined rotational position of the cam and the motor parameter being less than the threshold.

[0074] Article 3: The power tool according to Article 1, wherein the object includes a magnet.

[0075] Article 4: The power tool according to Article 3, wherein the sensor is a Hall effect sensor configured to detect the position of the magnet.

[0076] Article 5: The power tool according to Article 4, wherein the Hall effect sensor is configured to detect the position of the magnet when the magnet is at the predetermined rotational position of the cam.

[0077] Article 6: The power tool according to Article 5, wherein the speed ramp-down is a linear speed ramp-down.

[0078] Article 7: The power tool according to Article 1, wherein the sensor includes an inductive sensor.

[0079] Article 8: The power tool according to Article 7, wherein the inductive sensor is configured to detect the position of the object when the object is at the predetermined rotational position of the cam.

[0080] Article 9: The power tool according to Article 8, wherein the speed ramp-down is a linear speed ramp-down.

[0081] Article 10: The power tool described in Article 1, wherein the motor parameter is the speed of the motor, and the threshold is the speed threshold of the motor.

[0082] Article 11: A method of operating a power tool, the power tool including a drive blade extending along a drive axis and a cam assembly, the cam assembly including a cam configured to rotate about a rotational axis to move the drive blade, the cam including an object that rotates with the cam, the method including: receiving, at a controller of the power tool, a signal from a sensor indicating that the object is at a predetermined rotational position of the cam, comparing a motor parameter with a threshold, and initiating a speed ramp-down in response to the object being at the predetermined rotational position of the cam and the motor parameter being greater than or equal to the threshold.

[0083] Article 12: The method described in Article 11, wherein the object includes a magnet.

[0084] Article 13: The method described in Article 12, wherein the sensor is a Hall effect sensor, the method further including: detecting the position of the magnet via the Hall effect sensor.

[0085] Article 14: The method described in Article 13, the method further including detecting the position of the magnet via the Hall effect sensor when the magnet is at the predetermined rotational position of the cam.

[0086] Article 15: The method described in Article 14, wherein the speed ramp-down is a linear speed ramp-down.

[0087] Article 16: The method described in Article 11, wherein the sensor includes an inductive sensor.

[0088] Article 17: The method described in Article 16, the method further including: detecting the object via the inductive sensor when the object is at the predetermined rotational position of the cam.

[0089] Article 18: The method described in Article 17, wherein the speed ramp-down is a linear speed ramp-down.

[0090] Article 19: The method described in Article 11, wherein the motor parameter is the speed of the motor, and the threshold is the speed threshold of the motor.

[0091] Article 20: A power tool includes: a housing, a motor positioned at least partially within the housing, a drive blade extending along a drive axis, and a cam assembly. The cam assembly includes a cam configured to rotate about a rotational axis to move the drive blade. The cam includes an object that rotates with the cam. A sensor is configured to detect the object when the object is at a predetermined rotational position of the cam. A controller is connected to the motor and the sensor. The controller is configured to: receive a signal from the sensor indicating that the object is at the predetermined rotational position of the cam, compare a motor parameter with a threshold, and initiate a speed ramp-down in response to the object being at the predetermined rotational position of the cam and the motor parameter being greater than or equal to the threshold.

[0092] Accordingly, the specific embodiments of the present utility model particularly provide a power tool including closed-loop speed control. The claims set forth various features and advantages.

Claims

1. An electric tool, characterized in that, Comprising: A housing, the housing including a drive unit support portion, a cylinder support portion, and a handle portion; A motor, the motor being at least partially positioned within the drive unit support portion; A storage chamber cylinder, the storage chamber cylinder being at least partially positioned within the cylinder support portion; An inner cylinder, the inner cylinder having an annular inner wall defining a drive axis, at least a portion of the annular inner wall being within the storage chamber cylinder; A drive blade, the drive blade extending along the drive axis; A cam assembly, the cam assembly including a cam configured to rotate about a rotation axis to move the drive blade, the cam including an object that rotates with the cam; A sensor, the sensor being configured to detect the object when the object is at a predetermined rotational position of the cam; And A controller, the controller being connected to the motor and the sensor, the controller being configured to: receive a signal from the sensor indicating that the object is at a predetermined rotational position of the cam, Compare a motor parameter with a threshold, and In response to the object being at a predetermined rotational position of the cam and the motor parameter being greater than or equal to the threshold, initiate a speed ramp down.

2. The power tool according to claim 1, characterized in that, The controller is configured not to initiate the speed ramp down in response to the object being at a predetermined rotational position of the cam and the motor parameter being less than the threshold.

3. The power tool according to claim 1, characterized in that, The object includes a magnet.

4. The power tool according to claim 3, characterized in that, The sensor is a Hall effect sensor configured to detect the position of the magnet.

5. The electric tool according to claim 4, characterized in that, The Hall effect sensor is configured to detect the position of the magnet when the magnet is at a predetermined rotational position of the cam.

6. The electric tool according to claim 5, wherein, The speed ramp down is a linear speed ramp down.

7. The power tool according to claim 1, wherein, The sensor includes an inductive sensor.

8. The power tool according to claim 7, characterized in that, The inductive sensor is configured to detect the position of the object when the object is at a predetermined rotational position of the cam.

9. The power tool according to claim 8, characterized in that, The speed ramp down is a linear speed ramp down.

10. The power tool according to claim 1, characterized in that, The motor parameter is the speed of the motor, and the threshold is the speed threshold of the motor.

11. An electric tool, characterized in that, Comprising: A housing; A motor, the motor being at least partially positioned within the housing; A drive blade, the drive blade extending along a drive axis; A cam assembly, the cam assembly including a cam configured to rotate about a rotation axis to move the drive blade, the cam including an object that rotates with the cam; A sensor, the sensor being configured to detect the object when the object is at a predetermined rotational position of the cam; A controller, the controller being connected to the motor and the sensor, the controller being configured to: Receive a signal from the sensor indicating that the object is at a predetermined rotational position of the cam, Compare a motor parameter with a threshold, and In response to the object being at a predetermined rotational position of the cam and the motor parameter being greater than or equal to the threshold, initiate a speed ramp down.

12. The power tool according to claim 11, characterized in that, The controller is configured not to initiate the speed ramp down in response to the object being at a predetermined rotational position of the cam and the motor parameter being less than the threshold.

13. The power tool according to claim 11, characterized in that, The object includes a magnet.

14. The power tool according to claim 13, wherein, The sensor is a Hall effect sensor configured to detect the position of the magnet.

15. The power tool according to claim 14, wherein, The Hall effect sensor is configured to detect the position of the magnet when the magnet is at a predetermined rotational position of the cam.

16. The electric tool according to claim 15, characterized in that, The speed ramp is a linear speed ramp.

17. The electric tool according to claim 11, wherein, The sensor includes an inductive sensor.

18. The electric tool according to claim 17, characterized in that, The inductive sensor is configured to detect the position of the target when the target is at a predetermined rotational position of the cam.

19. The power tool according to claim 18, characterized in that, The speed ramp is a linear speed ramp.

20. The power tool according to claim 11, characterized in that, The motor parameter is the speed of the motor, and the threshold is the speed threshold of the motor.

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