Hinge Mounting System for Thermal Stress in Weighing Sensors
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Solution Overview
Problem
Weighing devices face accuracy issues due to mechanical stresses caused by temperature changes and differing material expansions, which existing mounting systems fail to adequately prevent from affecting the sensitive regions of load sensors.
Innovation Solution
The use of a hinge structure with flexure hinges in at least three mounting regions allows for linear motion between components, mitigating thermal expansion stresses by enabling translatory or tilting motions that maintain the aspect ratios and angles of the connected units, thereby preventing stress transmission to the sensitive sensor regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If components of different materials are rigidly connected to prevent relative movement, then structural stability is improved, but thermal expansion stresses cause deformation and measuring errors
Solution Approach 1:
The mounting system transitions from a rigid static connection to a dynamic connection that allows controlled movement. The hinge structure enables the mounting regions to move relative to each other in response to thermal expansion, accommodating dimensional changes while maintaining structural integrity and preventing stress transmission to the sensor.
Solution Approach 2:
The system changes the physical state of the connection from rigid fixed to articulated movable. By introducing hinge joints with specific degrees of freedom, the mounting system can adapt its geometry dynamically, allowing thermal expansion without generating harmful stresses in the sensor region.
2Reliability
If mounting regions are made large to ensure stable connection, then connection stability is improved, but stress transmission to the sensor region increases
Solution Approach 1:
The mounting system is divided into multiple independent mounting regions (at least three) that are distributed around the sensor. Each mounting region is kept small in size to minimize stress transmission, yet collectively they provide stable support. The hinge connections allow each region to move independently, preventing stress concentration.
3Object-affected harmful factors
If holding clamps are used to isolate the weighing system from base plate distortions, then protection from mechanical stresses is improved, but thermal expansion stresses between clamps and weighing system cannot be prevented
Solution Approach 1:
The hinge structure acts as an intermediary element between the mounting regions and the weighing system. It provides a compliant connection that mediates between the thermal expansion of different components, allowing relative movement while maintaining connection, thus preventing both mechanical distortion transmission and thermal stress accumulation.
4Device complexity
If flange elements are made integral with the base body to prevent stress transmission, then structural simplicity is improved, but stresses cannot be reliably prevented in sensitive regions
Solution Approach 1:
Instead of relying on integral rigid flange elements, the invention uses separate mounting regions connected via hinge joints. This dynamic articulation allows the structure to adapt to thermal expansion while maintaining simplicity in the sense of fewer stress transmission paths to the sensor region.
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 solution effectively prevents mechanical stresses from affecting the accuracy and stability of weighing devices by allowing controlled motion within the mounting regions, ensuring temperature stability and long-term accuracy of the weighing device.
Implementation Method 1
Mechanical stresses of this type may be created when the two components are connected, or may be caused by different thermal expansions after a temperature change
Implementation Method 2
The mounting regions... have a small size in comparison with the overall dimensions of the components such that stresses that may be generated within the mounting regions can be neglected
Data Source
AI summary
A weighing device, particularly an electromagnetic force compensating weighing device, with a weighing sensor unit connected in at least three mounting regions to a second unit such as a carrier unit or intermediate load plate. The second unit or the weighing sensor unit has connecting regions in at least two mounting regions, which employ a hinge structure that allows an essentially translatory shifting motion of the connecting region to avoid stress caused by temperature related expansion.