Power Tool Position Locking for Screw Joint Quality Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Unacceptably tightened screw joints often go uncorrected during assembly line operations due to operator neglect or distraction, leading to potential hazards and reduced assembly quality.
Innovation Solution
A control device and method that locks the power tool's operation to the screw joint or object with an unacceptable tightening result, ensuring correction before proceeding, using a combination of radio-frequency communication, position sensing, and locking mechanisms to ensure attention is given to faulty screw joints or malfunctioning tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power tool moves on to the next screw joint after a NOK indication, then productivity is improved, but the quality and reliability deteriorate because uncorrected faulty screw joints are left unattended
Solution Approach 1:
The control device continuously monitors tightening parameters (torque, angle, time) and provides immediate feedback through NOK/OK indications. When a NOK condition is detected, the system feeds back a lock signal that prevents the power tool from moving to the next joint until correction is made, ensuring quality without permanently stopping production
Solution Approach 2:
The system dynamically adjusts its behavior based on real-time conditions. During normal operation, the power tool moves freely between joints for high productivity. Upon detecting a NOK condition, the system dynamically locks the tool to that specific joint, forcing correction. This dynamic switching between free movement and locked correction mode resolves the contradiction between speed and quality
2Reliability
If the operator is forced to correct every NOK indication immediately, then quality is improved, but productivity deteriorates due to repeated corrections and downtime
Solution Approach 1:
The system performs preliminary detection of faulty screw joints before they become critical quality issues. By detecting NOK conditions immediately after tightening and locking the tool at that moment, the system prevents the accumulation of multiple uncorrected faults, reducing the need for extensive rework later while maintaining quality
Solution Approach 2:
The system automatically manages the correction process by locking the tool to the faulty joint and preventing movement until correction is made. The operator simply needs to perform the correction action, and the system self-manages the enforcement of quality requirements without needing constant operator intervention or supervision
3Ease of operation
If the power tool operates without position locking after NOK indication, then ease of operation is improved, but harmful factors increase as uncorrected faulty joints compromise assembly safety
Solution Approach 1:
The control device acts as an intermediary between the operator and the power tool motor. It receives signals from the tightening parameter sensors and translates them into control signals that either permit normal operation or enforce locking. This intermediary layer automatically enforces quality requirements without adding physical complexity to the power tool itself, maintaining ease of operation while preventing hazards
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
Guarantees that unacceptably tightened screw joints are addressed before further assembly, enhancing the quality of the final product by forcing operators to correct issues before moving on, thereby preventing hazardous outcomes and ensuring proper assembly.
Implementation Method 1
a portable battery powered tool having R-F transceiver means for communicating via radio waves with a stationary operation control unit
Data Source
Figure 1~2
AI summary
A method and a device for locking the operation of a power wrench (15;25)to the location of an unacceptably tightened screw joint (13a, b,c; 23a, b,c) or object (12a, b,c; 22a, b,c) with a sensing means for at least one tightening parameter, wherein a position sensing system (15, 19, 20; 35-37, 24) is provided for indicating continuously the position of the power wrench (15,25) during tightening operations, and a control unit (16, -26) comprising means for comparing obtained tightening parameter values with predetermined limit values and to provide an OK or a NOK signal in response to those limit values being passed or not for each screw joint, and a lock means to lock the power wrench operation to the very position of the screw joint or the object for which a NOK signal has been issued until the unacceptably tightened screw joint has been attended to and the NOK signal is removed.