Abstract: A power tool is provided including a housing, an electric motor disposed within the housing, a power switch circuit disposed between a power supply and the electric motor, a main controller, and a secondary controller. The main controller is arranged to control a switching operation of the power switch circuit to regulate a speed of the motor, and is configured to monitor at least one of a speed or a rotational direction of the electric motor and deactivate the power switch circuit upon detection of fault condition associated the speed or the rotational direction of the electric motor. The secondary controller is configured to monitor at least one of the speed or the rotational direction of the electric motor independently from the main controller and deactivate the power switch circuit upon detection of fault condition associated the speed or the rotational direction of the electric motor.

Abstract: A power tool includes a housing, a motor received in the housing, an output driven by the motor, and a control system. The control system includes a rotational motion sensor configured to generate a rotational motion signal that corresponds to a rotational motion of the housing about an axis, a current sensor configured to generate a motor current signal that corresponds to an amount of current drawn by the motor, and a control circuit that is configured to receive the rotational motion signal and the motor current signal and to control operation of the motor. The control circuit is configured: (a) to determine, based on the current signal, whether a detected kickback condition is likely to be false; (b) to determine, based upon the rotational motion signal, whether an uncontrolled kickback condition has occurred; and (c) to initiate one or more protective operations upon determining that an uncontrolled kickback condition has occurred and is not likely to be false.

Abstract: A power tool is provided including an electric motor, a power terminal receiving electric power form a power supply, an actuator, a power switch circuit disposed between the power terminal and the electric motor, and a controller controlling a switching operation of the power switch circuit. A power contact switch is coupled to the actuator and disposed on a first current path to selectively connect the power switch circuit to the power supply. A solid-state load switch disposed on a second current path from the power terminal to the controller is controllable via output of the power contact switch or a self-activating feedback signal from the controller. A solid-state override switch is provided controllable via a self-deactivating feedback signal from the controller and having an output commonly coupled to the output of the power contact switch to turn off the load switch even when the power contact switch is closed.

Abstract: A power tool is provided including a housing, a brushless direct-current (BLDC) electric motor disposed inside the housing, power switches disposed between a power supply and the electric motor and including high-side switches and low-side switches, and a control unit configured to control a switching operation of the power switches to operate the electric motor and electronically brake the motor by simultaneously activating the high-side switches or the low-side switches to stop the rotation of the motor upon detection of a condition prompting the braking of the motor. The control unit is configured to detect the condition that prompts the braking of the electric motor, set a braking profile for braking the electric motor based on the detected condition, and execute braking of the electric motor using the braking profile.

Abstract: A power tool is provided including a housing, an electric motor disposed within the housing, a power switch circuit disposed between a power supply and the electric motor, a main controller, and a secondary controller. The main controller is arranged to control a switching operation of the power switch circuit to regulate a speed of the motor, and is configured to monitor at least one of a speed or a rotational direction of the electric motor and deactivate the power switch circuit upon detection of fault condition associated the speed or the rotational direction of the electric motor. The secondary controller is configured to monitor at least one of the speed or the rotational direction of the electric motor independently from the main controller and deactivate the power switch circuit upon detection of fault condition associated the speed or the rotational direction of the electric motor.

Abstract: A power tool is provided including a housing, an electric motor disposed within the housing, a power switch circuit disposed between a power supply and the electric motor, a main controller, and a redundant controller. The main controller is arranged to control a switching operation of the power switch circuit to regulate a speed of the motor, and is configured to monitor at least one of a speed or a rotational direction of the electric motor and deactivate the power switch circuit upon detection of fault condition associated the speed or the rotational direction of the electric motor. The redundant controller is configured to monitor at least one of the speed or the rotational direction of the electric motor independently from the main controller and deactivate the power switch circuit upon detection of fault condition associated the speed or the rotational direction of the electric motor.

Abstract: A power tool includes a housing, a motor received in the housing, an output driven by the motor, and a control system. The control system includes a rotational motion sensor configured to generate a rotational motion signal that corresponds to a rotational motion of the housing about an axis, a current sensor configured to generate a motor current signal that corresponds to an amount of current drawn by the motor, and a control circuit that is configured to receive the rotational motion signal and the motor current signal and to control operation of the motor. The control circuit is configured: (a) to determine, based on the current signal, whether a detected kickback condition is likely to be false; (b) to determine, based upon the rotational motion signal, whether an uncontrolled kickback condition has occurred; and (c) to initiate one or more protective operations upon determining that an uncontrolled kickback condition has occurred and is not likely to be false.

Abstract: A power tool is provided including an electric motor, a power terminal receiving electric power form a power supply, an actuator, a power switch circuit disposed between the power terminal and the electric motor, and a controller controlling a switching operation of the power switch circuit. A power contact switch is coupled to the actuator and disposed on a first current path to selectively connect the power switch circuit to the power supply. A solid-state load switch disposed on a second current path from the power terminal to the controller is controllable via output of the power contact switch or a self-activating feedback signal from the controller. A solid-state override switch is provided controllable via a self-deactivating feedback signal from the controller and having an output commonly coupled to the output of the power contact switch to turn off the load switch even when the power contact switch is closed.

Abstract: A power tool includes a housing, a motor received in the housing, an output driven by the motor, and a control system. The control system includes a rotational motion sensor configured to generate a rotational motion signal that corresponds to a rotational motion of the housing about an axis, a current sensor configured to generate a motor current signal that corresponds to an amount of current drawn by the motor, and a control circuit that is configured to receive the rotational motion signal and the motor current signal and to control operation of the motor. The control circuit is configured: (a) to determine, based on the current signal, whether a detected kickback condition is likely to be false; (b) to determine, based upon the rotational motion signal, whether an uncontrolled kickback condition has occurred; and (c) to initiate one or more protective operations upon determining that an uncontrolled kickback condition has occurred and is not likely to be false.

Abstract: A power tool is provided including a housing; an electric motor disposed within the housing; a power terminal that receives electric power from a battery pack; a power switch circuit disposed between the power terminal and the electric motor; and a controller configured to control a switching operation of the power switch circuit to regulate power being supplied from the power terminal to the electric motor. The controller is configured to receive a temperature signal indicative of a temperature of the battery pack, determine if the temperature of the battery pack is below a lower temperature threshold, and operate the switching operation of the power switch circuit in a normal mode of operation if the temperature of the battery pack is greater than or equal to the low temperature threshold and in a cold mode of operation if the temperature of the battery pack is below the low temperature threshold.

Abstract: A power tool is provided including a housing; an electric motor disposed within the housing; a power terminal arranged to received electric power form a battery pack; a power switch circuit disposed between the power terminal and the electric motor; and a controller configured to control a switching operation of the power switch circuit to regulate power being supplied from the power terminal to the electric motor. The controller is configured to receive a temperature signal indicative of a temperature of the battery pack, determine if the temperature of the battery pack is below a lower temperature threshold, and operate the switching operation of the power switch circuit in a normal mode of operation if the temperature of the battery pack is greater than or equal to the low temperature threshold and in a cold mode of operation if the temperature of the battery pack is below the low temperature threshold.

Abstract: A power tool is provided including a housing, an electric motor disposed within the housing, a power switch circuit disposed between a power supply and the electric motor, a main controller, and a redundant controller. The main controller is arranged to control a switching operation of the power switch circuit to regulate a speed of the motor, and is configured to monitor at least one of a speed or a rotational direction of the electric motor and deactivate the power switch circuit upon detection of fault condition associated the speed or the rotational direction of the electric motor. The redundant controller is configured to monitor at least one of the speed or the rotational direction of the electric motor independently from the main controller and deactivate the power switch circuit upon detection of fault condition associated the speed or the rotational direction of the electric motor.

Abstract: A power tool includes a housing, a motor received in the housing, an output driven by the motor, and a control system. The control system includes a rotational motion sensor configured to generate a rotational motion signal that corresponds to a rotational motion of the housing about an axis, a current sensor configured to generate a motor current signal that corresponds to an amount of current drawn by the motor, and a control circuit that is configured to receive the rotational motion signal and the motor current signal and to control operation of the motor. The control circuit is configured: (a) to determine, based on the current signal, whether a detected kickback condition is likely to be false; (b) to determine, based upon the rotational motion signal, whether an uncontrolled kickback condition has occurred; and (c) to initiate one or more protective operations upon determining that an uncontrolled kickback condition has occurred and is not likely to be false.

Abstract: A power tool is provided including a housing, a brushless direct-current (BLDC) electric motor disposed inside the housing, power switches disposed between a power supply and the electric motor and including high-side switches and low-side switches, and a control unit configured to control a switching operation of the power switches to operate the electric motor and electronically brake the motor by simultaneously activating the high-side switches or the low-side switches to stop the rotation of the motor upon detection of a condition prompting the braking of the motor. The control unit is configured to detect the condition that prompts the braking of the electric motor, set a braking profile for braking the electric motor based on the detected condition, and execute braking of the electric motor using the braking profile.

Abstract: The joint construction is employed between a military rocket motor and a warhead adapted to be propelled by the motor. The motor includes a motor tube with a cylindrical front portion having an internal cylindrical surface therein. The warhead comprises an adapter ring having a cylindrical rear portion with an external cylindrical surface which is telescopically receivable within the internal cylindrical surface. The internal and external cylindrical surfaces are formed with respective confronting aligned internal and external helical screw thread grooves for receiving a fusible substantially helical joint member to form a secure connection between the rocket motor and the warhead. The helical joint member is made of a material having a low melting temperature, preferably a eutectic metal alloy, whereby the heat of a fire or the like will melt the joint member to disconnect the warhead from the rocket motor. The motor tube has a front wall with a vent opening therein, normally closed by a plug member.

Abstract: The ignition safety device is mounted on a rocket motor nozzle having a body with a longitudinal nozzle opening having an igniter therein for igniting the propulsion charge of the rocket motor. An electrically operable detonator is mounted in a detonator opening in a housing mounted in the body. An actuator and a locking member are movable in the body between safe and armed positions. The locking member has means operative in its safe position for locking the actuator. Movement of the locking member to its armed position unlocks the actuator. A spring biases the locking member to its safe position. The actuator is adapted to operate a switch which initially short circuits the electrically operable detonator but is operable by the actuator to an armed position in which the detonator is no longer short circuited and is connected to an electrical input circuit including a contact band on the nozzle body.