Impact Wrench Torque Monitoring for Expansion Anchor Setting
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Solution Overview
Problem
The improper second tightening of expansion anchors can damage the anchors, and existing methods for securing structural beams using expansion anchors are labor-intensive and risk injury to the user, especially when multiple anchors are required.
Innovation Solution
A two-phase setting method for expansion anchors using an impact wrench, where the first phase estimates and exceeds a torque threshold, followed by a second phase with a controlled number of rotary impacts, and a modified phase based on torque rate change monitoring to prevent damage, ensuring accurate tightening without overloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a user loosens and retightens expansion anchors manually for alignment, then the structural beams can be aligned, but the expansion anchor may be damaged by improper second tightening
Solution Approach 1:
The patent replaces manual mechanical tightening operations with an automated impact wrench system that uses controlled rotary impacts. The system substitutes human judgment and manual torque application with electronic control algorithms that monitor torque development in real-time and automatically adjust the number of impacts to achieve precise tightening without overloading the anchor.
Solution Approach 2:
The system implements continuous feedback by monitoring the torque developed during each rotary impact phase. The control algorithm adjusts the number of impacts in the second phase based on the actual torque development observed in the first phase, creating a closed-loop control system that prevents damage while ensuring proper tightening.
2Productivity
If multiple expansion anchors are secured using manual methods, then the structural beams can be fastened, but the process becomes labor-intensive and risks user injury
Solution Approach 1:
The impact wrench system performs the tightening operation autonomously without requiring user intervention during the critical tightening phases. The system self-regulates the number of impacts based on real-time torque monitoring, eliminating the need for users to manually control each anchor while reducing injury risk from repetitive manual operations.
Solution Approach 2:
The system replaces dangerous manual mechanical operations with an automated powered tool that controls high-torque impacts electronically. This substitution eliminates user exposure to harmful forces while dramatically increasing fastening efficiency through automated multi-phase tightening sequences.
3Device complexity
If a fixed number of rotary impacts are applied in the second phase, then the tightening process is simple, but it cannot adapt to unknown influences such as wall condition
Solution Approach 1:
The system transitions from a static fixed-impact approach to a dynamic adaptive control system. The number of impacts in the second phase is not predetermined but dynamically adjusted based on real-time torque development. This allows the system to adapt to varying wall conditions, anchor installations, and structural requirements while maintaining a relatively simple two-phase operational structure.
Solution Approach 2:
The control algorithm changes the impact parameter (number of impacts) based on observed torque development. By monitoring how torque develops during the first phase and adjusting the second-phase impact count accordingly, the system adapts to unknown influences such as wall condition, anchor positioning accuracy, and structural beam alignment status without requiring complex pre-programming.
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
This method ensures precise and safe tightening of expansion anchors, reducing the risk of damage and user injury, while being more robust against unknown influences, such as the condition of the wall, and allowing for efficient alignment and secure fastening of structural beams.
Implementation Method 1
a first number of rotary impacts specified for the expansion anchor are exerted on the screw head
Implementation Method 2
An expansion mechanism 39 is provided at an end remote from the screw head 21. The expansion mechanism 39 converts a tensile stress from the screw head 21 acting on the expansion mechanism 39 into a radial clamping force against the inner wall of the borehole
Data Source
AI summary
A setting method for expansion anchors via an impact wrench has a first phase S1 and a second phase S2. In the first phase, a rotary impact is repeatedly exerted on a screw element of the expansion anchor and a torque transmitted from the rotary impact to the screw head is estimated. The first phase S1 is ended when the estimated transmitted torque exceeds a threshold value specified for the expansion anchor. During the second phase, a first number of rotary impacts specified for the expansion anchor are exerted on the screw head. A current rate of change of the estimated torque is monitored at least during the first phase. In response to the current rate of change exceeding a limit value for the rate of change specified for the expansion anchor, a modified second phase is started, in which a second number of rotary impacts specified for the expansion anchor are exerted on the screw head, the second number being less than the first number.