Driver Bit Position Control for Flush Screw Fastening

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Solution Overview

Problem

Existing fastening tools face challenges in controlling the movement end position of the driver bit, making it difficult to achieve a flush state of the screw head with the fastening target.

Innovation Solution

A fastening tool with a bit holding portion that rotates and moves axially, controlled by a motor and a control unit, which initializes and adjusts the bit's position based on motor rotations and contact with the target.

Engineering Contradictions & Design Principles

VSEngineering 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 state with the fastening target

Engineering Contradiction:

Improvemovement end position control precisionVSAvoidcontrol system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control unit monitors the actual movement distance of the driver bit and compares it with the target distance, adjusting the motor operation to achieve precise positioning. This feedback mechanism enables accurate control of the driver bit's movement end position to ensure the screw head is flush with the fastening target.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the purely mechanical positioning systems (pneumatic or spring-driven) with an electric motor system controlled by a control unit. This substitution enables programmable and precise control of the driver bit's movement distance, overcoming the limitations of mechanical systems while maintaining operational simplicity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the driver bit moves quickly to tighten the screw, then productivity increases, but control over the movement end position becomes more difficult

Engineering Contradiction:

Improvescrew insertion speedVSAvoidmovement end position control precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The control unit dynamically adjusts the motor's operation based on real-time feedback, allowing the driver bit to move quickly during the majority of the行程 and then decelerate precisely as it approaches the target position. This dynamic control enables both high productivity and accurate positioning.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The motor operation is divided into multiple phases: acceleration phase, constant speed phase, and deceleration phase. This periodic action pattern allows the driver bit to maintain high speed during the constant speed phase for productivity while achieving precise positioning during the deceleration phase near the end position.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS20250345901A1Fastening tool

Publication Date: 2025.11.13 MAX CO LTD

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 perform at least one of rotation of the bit holding portion and movement of the bit holding portion along the axial direction; a contact member which contacts a fastening target and is configured to move in the axial direction; a control unit configured to control a timing at which driving of the motor is stopped based on a movement amount of the contact member in the axial direction when the contact member contacts the fastening target; a contact arm which is movable in the axial direction in conjunction with the contact member; and a position detection unit configured to detect a position of the contact arm.