Fastening Tool Bit Position Control for Flush Screw Tightening
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Solution Overview
Problem
Existing fastening tools struggle to accurately control the movement end position of a driver bit during screw tightening, making it difficult to achieve a flush head portion with the fastening target.
Innovation Solution
A fastening tool with a bit holding portion that rotates and moves axially, driven by a motor, and a control unit that adjusts the bit's position using motor rotations, along with a contact member to stop driving based on target contact and a fluctuation detection unit to stabilize motor speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pneumatic screw driving machine or spring-driven screwdriver is used, then the screw can be driven, but it is difficult to control the movement end position of the driver bit and achieve flush head portion with fastening target
Solution Approach 1:
The patent employs feedback control by detecting the actual movement amount of the driver bit and comparing it with the target movement amount. The control unit adjusts the motor operation based on this feedback to achieve precise positioning of the driver bit, ensuring the screw head is flush with the fastening target surface.
Solution Approach 2:
The patent replaces the purely mechanical drive mechanisms (pneumatic or spring-driven) with an electric motor system that incorporates electronic control. This substitution enables precise control of the driver bit's movement end position through electronic feedback control, overcoming the limitations of mechanical systems.
2Productivity
If motor rotates bit holding portion, then screw tightening is achieved, but fluctuation in rotation speed occurs affecting precision
Solution Approach 1:
The patent uses feedback control to detect fluctuations in motor rotation speed and implements corrective actions. The control unit monitors the actual rotation speed and adjusts the motor operation to maintain stable rotation, ensuring both high productivity and precision in screw tightening operations.
Data Source
AI summary
A fastening tool includes: a bit holding portion which detachably holds a driver bit and is configured to rotate in a circumferential direction of the driver bit and move in an axial direction of the driver bit; a motor configured to move the bit holding portion along the axial direction; and a control unit configured to control a position of the bit holding portion along the axial direction by the number of rotations of the motor. The control unit is configured to execute an initialization operation of setting a standby position of the bit holding portion along the axial direction, and control a position of the bit holding portion along the axial direction from the standby position by the number of rotations of the motor.