Gap-Limited Load Cell Structure for Overload Protection
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Solution Overview
Problem
Conventional disc-type load cells are prone to irreversible permanent deformation and damage due to overload, limiting their measurement range and durability.
Innovation Solution
Incorporating a limitation element with a designed gap into the load cell structure to limit deformation within a specific range, using a limitation element to support the elastic element and prevent damage, and sealing the strain gauge with a sealant to protect it from moisture and dust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the elastic element is made of sturdy material (aluminum, alloy steel, or stainless steel), then the load cell has high strength and durability, but the elastic element becomes minimally elastic and prone to irreversible permanent deformation when overloaded
Solution Approach 1:
The elastic element is divided into two functional parts: a deformation region that can elastically deform to measure force, and a non-deformation region that maintains structural integrity and prevents irreversible deformation. This segmentation allows the load cell to achieve both high strength and reliability by having different regions serve different functions.
Solution Approach 2:
Different regions of the elastic element are given different mechanical properties: the deformation region is designed to be elastic and deformable for measurement, while the non-deformation region is designed to be rigid and resistant to permanent deformation. This local differentiation resolves the contradiction between overall strength and resistance to irreversible deformation.
2Measurement precision
If the load cell is designed to measure force within a specific range, then the measurement precision is improved, but the load cell becomes vulnerable to damage when subjected to excessive forces
Solution Approach 1:
The non-deformation region is designed in advance to act as a protective cushion against excessive forces. When the applied force exceeds the measurement range, the non-deformation region absorbs the excess force and prevents it from reaching and damaging the strain gauge and other sensitive components, thus protecting the load cell before damage can occur.
Solution Approach 2:
The non-deformation region serves as an intermediary protective structure between the deformation region (where measurement occurs) and the external excessive forces. It mediates the interaction by absorbing and redistributing excessive forces away from the sensitive measurement components.
3Reliability
If the gap between the limitation element and elastic element is made larger, then the protection against overload is improved, but the measurement range is reduced
Solution Approach 1:
The gap between the limitation element and elastic element is designed to be dynamic rather than fixed. Under normal operating forces within the measurement range, the gap remains closed or minimal, allowing full measurement capability. When excessive forces are applied, the deformation region can deform to close the gap, activating the protective mechanism. This dynamic behavior allows the system to adapt between measurement mode and protection mode.
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
The load cell effectively measures forces within a specific range while preventing irreversible deformation and protecting the strain gauge, allowing it to withstand excessive loads without damage.
Implementation Method 1
The strain gauge is secured on the elastic element. When a force is exerted on the load cell, the elastic element is slightly deformed, and the shape of the strain gauge secured on the elastic element is also changed, so as to change the resistance of the strain gauge.
Implementation Method 2
The elastic element is usually made of aluminum, alloy steel or stainless steel which makes it very sturdy but also minimally elastic. When a force is exerted on the load cell, the elastic element is slightly deformed
Data Source
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AI summary
The disclosure relates to a load cell (1, 1a, 1b) including an elastic element (10), at least one strain gauge (S1, S2, S3, S4) and a limitation element (30, 30a). The elastic element (10) includes a first end portion (11a), a second end portion (12b) and a deformation region (13a). The first end portion (11a) and the second end portion (12b) are arranged along an axial direction and opposed to each other. The deformation region (13a) is located between the first end portion (11a) and the second end portion (12b). The at least one strain gauge (S1, S2, S3, S4) is disposed in the deformation region (13a). When a force (F1) is exerted on the first end portion in a first direction, the deformation region (13a) is deformed to drive the at least one strain gauge (S1, S2, S3, S4) to change shape, so that the force (F1) is measured and standardized under a specific range. The limitation element (30, 30a) is connected to the elastic element (10). A gap (G) is formed between the limitation element (30, 30a) and the elastic element (10).