Monoblock Load Cell Sensor Body With Stress-Isolating Mount Cavities

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Solution Overview

Problem

Existing monoblock sensor bodies face issues with stiffness and stability due to stress propagation paths from mounting screws, which affect the accuracy and performance of load cells, particularly in high-resolution applications.

Innovation Solution

The monoblock sensor body design incorporates cavities that reduce the solid angle for straight propagation paths from the inner thread to flexure points, using a closing material boundary to protect sensitive elements and enhance stiffness and stability, while maintaining sensor body geometry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mounting holes are provided in the monoblock sensor body for attaching mounting screws, then the sensor body can be mounted to housing sides and load receiving members, but stress propagation paths from the mounting screws affect the accuracy and performance of load cells

Engineering Contradiction:
Improvemounting capabilityVSAvoidload cell accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediate structural feature (the cavity with reduced solid angle) between the mounting hole and the flexure point sections. This intermediary structure intercepts and redirects stress propagation paths, preventing direct transmission of mounting screw stresses to the sensitive measurement regions, thereby protecting measurement precision while maintaining mounting capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts or removes material to create cavities in the mounting portions. By taking out material to form these cavities, the solid angle for stress propagation is reduced, which isolates the sensitive flexure point sections from stress generated by mounting screws, thus protecting measurement accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

2Stability of the object's composition

If the monoblock sensor body uses a robust mounting structure with mounting holes extending through the body, then mounting stability is improved, but deformation of pivot points and pivot axes occurs affecting high-resolution measurements

Engineering Contradiction:
Improvemounting stabilityVSAvoidpivot point position accuracy
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent converts the potentially harmful stress propagation from mounting screws into a beneficial isolation effect. By designing cavities that reduce the solid angle, the structure intentionally creates stress redirection paths that protect the pivot points, turning the mounting stress (harm) into a design feature that enhances measurement precision (benefit)

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent applies local quality modification by creating cavities specifically in the mounting portions near the flexure point sections. This localized structural modification targets only the areas where stress propagation occurs, leaving the rest of the monoblock body intact and maintaining overall structural stability while protecting critical measurement regions

Inventive Principle:
Principle #3Local quality

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 design increases measurement accuracy and stability by preventing deformation of pivot points and pivot axes, thereby improving the performance of load cells, especially in high-resolution weighing systems.

Implementation Method 1

the mounting hole comprising an inner thread such that a mating outer thread of a fixing screw screwed in the mounting state into the mounting hole

Methodology Applied
Scientific EffectThreaded fastening: Screw

Implementation Method 2

the parallel upper and lower beam of the Roberval mechanism connected each via first and second flexure point sections with the fixed, respectively the movable column

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

a Roberval mechanism is involved for receiving the load with its movable column

Methodology Applied
Scientific EffectMechanical equilibrium: Balance

Implementation Method 4

a lever arrangement is provided, coupled to the movable column of the Roberval mechanism, and the load measuring principle is that of the electromagnetic force compensation, a corresponding mechanism being connected to the lever arrangement

Methodology Applied
Scientific EffectLever mechanical advantage: Lever

Implementation Method 5

the load measuring principle is that of the electromagnetic force compensation

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP4063806B1Monoblock sensor body and method of its manufacturing
Publication Date: 2026.03.04 METTLER TOLEDO GMBH
  • EP4063806B1 patent drawingFigure 1
  • EP4063806B1 patent drawingFigure 2
  • EP4063806B1 patent drawingFigure 3

AI summary

The invention relates to a monoblock sensor body of a load cell based on an electromagnetic force compensation mechanism, comprising a Roberval mechanism, a lever arrangement coupled on the one hand side by a coupling to the movable column of the Roberval mechanism and on the other hand side connectable to the electromagnetic force compensation mechanism and having one or more levers with respective fulcrums, the body further comprising mounting portions for mounting the fixed column of the Roberval mechanism to a housing side of a weighing module, directly or indirectly via an intermediate arrangement, and/or for mounting a load receiving member to the movable column, directly or via an intermediate arrangement, at least one mounting portion thereof comprising at least one mounting hole extending preferably at least predominantly orthogonal to the load direction, in particular along the length direction of the parallel upper and lower beam of the Roberval mechanism connected each via first and second flexure point sections with the fixed, respectively the movable column, said mounting hole comprising an inner thread such that a mating outer thread of a fixing screw screwed in the mounted state into the mounting hole up to an axial threading end can be screwed into the mounting hole, the mounting hole having one of the first upper, second upper, first lower, and second lower flexure point section as relatively closest flexure point section, whereby at least one mounting portion comprising a cavity reduces the available solid angle for straight propagation paths running from the inner thread to one or more of the closest flexure point section, coupling and the in particular closest fulcrum while a material boundary of the body closes the cavity over at least a bridging width versus the height-side end of the body corresponding to the closest flexure point section.