Power tools
First Claim
1. A power tool, comprising:
- a motor,means for generating an elevated torque, wherein the elevated torque generating means is coupled to the motor and has an output shaft, wherein if a load acting on the output shaft is less than a predetermined value, rotating torque generated by the motor is directly transmitted to the output shaft and if a load acting on the output shaft exceeds the predetermined value, an elevated torque is generated by the elevated torque generating means and applied to the output shaft, wherein the elevated torque generating means comprises an oil pulse unit driven by the motor,a load shaft connected to the output shaft,a plurality of magnets disposed around an outer surface of either the output shaft or the load shaft so that the magnets integrally rotate with the output shaft or the load shaft, each magnet having a South pole and a North pole, wherein the South poles are disposed in an alternating relationship with the North poles,a first sensor fixedly disposed relative to the magnets, such that the first sensor will not rotate when the output shaft or load shaft rotates, wherein the first sensor latches its output signal to a first level when detecting a North pole magnetic field, and latches its output signal to a second level when detecting a South pole magnetic field, anda second sensor fixedly disposed relative to the magnets, such that the second sensor will not rotate when the output shaft or load shaft rotates, wherein the second sensor latches its output signal to the first level when detecting the North pole magnetic field, and latches its output signal to the second level when detecting the South pole magnetic field, wherein the output signal of the first sensor and the output signal of the second sensor are shifted by first phase when the output shaft or load shaft rotates in a direction of tightening a fastener, and are shifted by second phase when the output shaft or load shaft rotates in a direction of loosening the fastener.
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Accused Products
Abstract
Battery-powered tools may include battery 1 or battery pack BP and a drive source (e.g., motor M) for generating power using current supplied from the battery. A switch 3 may electrically connect the battery to the drive source. A voltage detector may detect the output battery voltage of the battery. Further, a processor 60, 210, a comparator 5 or another similar device preferably determines when a difference between (1) a first battery voltage detected at a first predetermined time period after the switch is turned OFF and (2) a second battery voltage detected at a second predetermined time after the first predetermined time period exceeds a predetermined value. This information may be utilized to determine whether to warn an operator of the battery powered tool that further operation using the battery 1 or battery pack BP should be discontinued.
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Citations
19 Claims
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1. A power tool, comprising:
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a motor, means for generating an elevated torque, wherein the elevated torque generating means is coupled to the motor and has an output shaft, wherein if a load acting on the output shaft is less than a predetermined value, rotating torque generated by the motor is directly transmitted to the output shaft and if a load acting on the output shaft exceeds the predetermined value, an elevated torque is generated by the elevated torque generating means and applied to the output shaft, wherein the elevated torque generating means comprises an oil pulse unit driven by the motor, a load shaft connected to the output shaft, a plurality of magnets disposed around an outer surface of either the output shaft or the load shaft so that the magnets integrally rotate with the output shaft or the load shaft, each magnet having a South pole and a North pole, wherein the South poles are disposed in an alternating relationship with the North poles, a first sensor fixedly disposed relative to the magnets, such that the first sensor will not rotate when the output shaft or load shaft rotates, wherein the first sensor latches its output signal to a first level when detecting a North pole magnetic field, and latches its output signal to a second level when detecting a South pole magnetic field, and a second sensor fixedly disposed relative to the magnets, such that the second sensor will not rotate when the output shaft or load shaft rotates, wherein the second sensor latches its output signal to the first level when detecting the North pole magnetic field, and latches its output signal to the second level when detecting the South pole magnetic field, wherein the output signal of the first sensor and the output signal of the second sensor are shifted by first phase when the output shaft or load shaft rotates in a direction of tightening a fastener, and are shifted by second phase when the output shaft or load shaft rotates in a direction of loosening the fastener. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A power tool, comprising:
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a motor; means for generating an elevated torque, wherein the elevated torque generating means is coupled to the motor and has an output shaft, wherein if a load acting on the output shaft is less than a predetermined value, rotating torque generated by the motor is directly transmitted to the output shaft and if a load acting on the output shaft exceeds the predetermined value, an elevated torque is generated by the elevated torque generating means and applied to the output shaft; a load shaft connected to the output shaft, the load shaft being designed to engage a fastener; a first sensor for detecting rotation of the output shaft or the load shaft; a second sensor for detecting rotation of the output shaft or the load shaft; and a microprocessor in communication with the motor, the first sensor and the second sensor, the first and second sensors communicating output signals to the microprocessor, wherein the microprocessor determines the direction of the rotation of the output shaft or load shaft based upon the phase difference between the output signal of the first sensor and the output signal of the second sensor, wherein the microprocessor determines the number of rotations of the output shaft or load shaft based upon the output signals of the first sensor or second sensor, and wherein the microprocessor further determines, based upon the direction of the rotation of the output shaft or load shaft and the number of rotations of the output shaft or load shaft, whether the number of rotations in the direction of tightening the fastener exceeds the stored number of rotations in the direction of loosening the fastener, and wherein the microprocessor determines that the rotation of the fastener has stopped when the number of rotations in the direction of tightening the fastener exceeds the stored number of rotations in the direction of loosening the fastener. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A power tool, comprising:
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a motor; means for generating an elevated torque, wherein the elevated torque generating means is coupled to the motor and has an output shaft, wherein if a load acting on the output shaft is less than a predetermined value, rotating torque generated by the motor is directly transmitted to the output shaft and if a load acting on the output shaft exceeds the predetermined value, an elevated torque is generated by the elevated torque generating means and applied to the output shaft; a load shaft connected to the output shaft, the load shaft being designed to engage a fastener; means for detecting the number of rotations of the output shaft or load shaft and the direction of the rotation of the output shaft or load shaft; and a microprocessor in communication with the motor and the detecting means, the detecting means communicating output signal to the microprocessor, wherein the microprocessor determines, based upon the direction of the rotation of the output shaft or load shaft and the number of rotations of the output shaft or load shaft, whether the number of rotations in the direction of tightening the fastener exceeds the stored number of rotations in the direction of loosening the fastener, and wherein the microprocessor determines that the rotation of the fastener has stopped when the number of rotations in the direction of tightening the fastener exceeds the stored number of rotations in the direction of loosening the fastener. - View Dependent Claims (17, 18)
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19. A power tool, comprising:
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a motor, means for generating an elevated torque, wherein the elevated torque generating means is coupled to the motor and has an output shaft, wherein if a load acting on the output shaft is less than a predetermined value, rotating torque generated by the motor is directly transmitted to the output shaft and if a load acting on the output shaft exceeds the predetermined value, an elevated torque is generated by the elevated torque generating means and applied to the output shaft, a load shaft connected to the output shaft, a plurality of magnets disposed around an outer surface of either the output shaft or the load shaft so that the magnets integrally rotate with the output shaft or the load shaft, each magnet having a South pole and a North pole, wherein the South poles are disposed in an alternating relationship with the North poles, a first sensor fixedly disposed relative to the magnets, such that the first sensor will not rotate when the output shaft or load shaft rotates, wherein the first sensor latches its output signal to a first level when detecting a North pole magnetic field, and latches its output signal to a second level when detecting a South pole magnetic field, a second sensor fixedly disposed relative to the magnets, such that the second sensor will not rotate when the output shaft or load shaft rotates, wherein the second sensor latches its output signal to the first level when detecting the North pole magnetic field, and latches its output signal to the second level when detecting the South pole magnetic field, wherein the output signal of the first sensor and the output signal of the second sensor are shifted by first phase when the output shaft or load shaft rotates in a direction of tightening a fastener, and are shifted by second phase when the output shaft or load shaft rotates in a direction of loosening the fastener, and a bearing rotatably supporting at least one of the output shaft or load shaft, the bearing comprising an inner cylinder and an outer cylinder rotatably supporting the inner cylinder, the inner cylinder being affixed the output shaft or load shaft via a through-opening defined within the inner cylinder, wherein the magnets are disposed on an outer surface of the inner cylinder and the first and second sensors are disposed on an inner surface of the outer cylinder.
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Specification