Power impact tool
First Claim
1. A power impact tool comprising:
- a hammer;
a driving mechanism for rotating the hammer around a driving shaft;
an output shaft to which a rotation force owing to an impact of the hammer is applied;
an impact sensor for sensing occurrence of the impact of the hammer;
a rotation speed sensor for sensing a rotation speed of the driving shaft with using a rotation angle of the driving shaft;
a rotation angle sensor for sensing a rotation angle of the output shaft in a term from a time when the impact sensor senses an occurrence of the impact of the hammer to another time when the impact sensor senses a next occurrence of the impact of the hammer;
a torque estimator for calculating an impact energy with using an average rotation speed of the driving shaft sensed by the rotation speed sensor, and for calculating a value of estimated torque for fastening a fastening member which is given as a division of the impact energy by the rotation angle of the output shaft;
a torque setter for setting a reference value of torque to be compared; and
a controller for stopping the rotation of the driving shaft when the value of the estimated torque becomes equal to or larger than a predetermined reference value set by the torque setter.
2 Assignments
0 Petitions
Accused Products
Abstract
In a power impact tool for fastening a fastening member, a torque for fastening the fastening member can be estimated without using a high-resolution sensor and a high-speed processor. The power impact tool comprises a rotation speed sensor for sensing a rotation speed of a driving shaft of a motor with using a rotation angle of the driving shaft, a rotation angle sensor for sensing a rotation angle of an output shaft to which a bit is fitted in a term between an impact of a hammer to next impact of the hammer, a torque estimator for calculating an impact energy with using an average rotation speed of the driving shaft and for calculating a value of estimated torque for fastening the fastening member which is given as a division of the impact energy by the rotation angle of the output shaft, a torque setter for setting a reference value of torque to be compared, and a controller for stopping the driving of the motor when the value of the estimated torque becomes equal to or larger than a predetermined reference value set by the torque setter.
48 Citations
9 Claims
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1. A power impact tool comprising:
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a hammer;
a driving mechanism for rotating the hammer around a driving shaft;
an output shaft to which a rotation force owing to an impact of the hammer is applied;
an impact sensor for sensing occurrence of the impact of the hammer;
a rotation speed sensor for sensing a rotation speed of the driving shaft with using a rotation angle of the driving shaft;
a rotation angle sensor for sensing a rotation angle of the output shaft in a term from a time when the impact sensor senses an occurrence of the impact of the hammer to another time when the impact sensor senses a next occurrence of the impact of the hammer;
a torque estimator for calculating an impact energy with using an average rotation speed of the driving shaft sensed by the rotation speed sensor, and for calculating a value of estimated torque for fastening a fastening member which is given as a division of the impact energy by the rotation angle of the output shaft;
a torque setter for setting a reference value of torque to be compared; and
a controller for stopping the rotation of the driving shaft when the value of the estimated torque becomes equal to or larger than a predetermined reference value set by the torque setter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification