Electronic Pulse Driver Torque Control via Prestart Power
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Solution Overview
Problem
Conventional power tools generate excessive torque when tightening screws, leading to over-tightening and inability to loosen fasteners efficiently due to differing coefficients of static and kinetic friction, making them less user-friendly.
Innovation Solution
An electronic pulse driver with a motor, hammer, anvil, and control unit that regulates the electric power supply to prevent excessive torque transfer by applying a prestart electric power lower than the drive power, allowing precise control of torque and enabling both tightening and loosening with the same torque setting through adjustable drive forces and rotation directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the motor supplies high drive force to the hammer, then the tightening torque is sufficient to secure the fastener, but the torque excessively exceeds the target torque causing over-tightening
Solution Approach 1:
The control unit supplies prestart electric power lower than drive electric power before the hammer contacts the anvil, allowing the hammer to approach the anvil at a reduced speed. This preliminary action prevents excessive impact torque when contact occurs, enabling precise torque control while still achieving sufficient tightening through subsequent drive power supply.
2Ease of operation
If the power tool uses the same torque setting for both tightening and loosening, then the device is more user-friendly, but the fastener cannot be loosened efficiently due to higher static friction
Solution Approach 1:
The power tool dynamically adjusts the drive force based on the operational phase. During loosening operations, the control unit supplies prestart electric power to enable the hammer to contact the anvil, then switches to drive electric power to provide sufficient impact force to overcome static friction. This dynamic adjustment allows efficient loosening while maintaining user-friendly single-setting operation.
3Speed
If the hammer strikes the anvil at high speed, then the tightening operation is faster, but the impact force generates excessive torque
Solution Approach 1:
The control unit supplies prestart electric power lower than drive electric power before the hammer contacts the anvil, allowing the hammer to approach the anvil at a reduced speed. This preliminary action prevents excessive impact torque when contact occurs, enabling precise torque control while still achieving sufficient tightening through subsequent drive power supply.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution prevents excessive torque application, enhances user operability by allowing precise torque control, and facilitates both tightening and loosening operations with improved efficiency and reduced unnecessary wait times.
Implementation Method 1
a motor 3, a hammer 42, and an anvil 52. The hammer 42 is connected to the motor 3 and rotatable by the motor 3
Implementation Method 2
The control unit controls the power supply unit to supply to the motor 3 a prestart electric power lower than the drive electric power before supplying the drive electric power
Implementation Method 3
The hammer collides with the anvil and imparts torque thereto. The torque provided to the anvil is transmitted to an end tool
Data Source
AI summary
An electronic pulse driver includes a motor, a hammer, an anvil, an end tool mounting unit, a power supply unit, and a control unit. The hammer is rotatable together with the anvil. The end tool mounting unit transmits the rotation of the anvil to an end tool. The power supply unit supplies a drive electric power to the motor. The control unit controls the power supply unit to halt a supply of the drive electric power to the motor when an electric current flowing to the motor increases to a prescribed value. The control unit controls the power supply unit to supply to the motor a prestart electric power lower than the drive electric power before supplying the drive electric power in order to permit the power supply unit to supply the drive electric power after the hammer is in contact with the anvil.