Load Cell Integrated Cable Bushing for Sealed Weighing

Solution Overview

Problem

Conventional load cells used in belt weighing devices, such as checkweighers and price labellers, require encapsulation for higher IP protection and food processing, which increases space and cost, and existing solutions fail to efficiently integrate motor cables without compromising environmental sealing.

Innovation Solution

A load cell design featuring an integrated cable bushing that allows the motor cable to run through the measuring body's cavity, eliminating the need for external encapsulation and separate cable guides, while maintaining hermetic sealing and enabling easy cleaning with high-pressure washes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the load cell and motor cable are encapsulated in a common housing for higher IP protection, then environmental sealing is improved, but space consumption and cost increase

Engineering Contradiction:

ImproveIP protectionVSAvoidspace consumption

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The cable bushing is integrated directly into the measuring body of the load cell, merging the cable guidance function with the load cell structure itself. This eliminates the need for separate encapsulation housing, reducing space while maintaining IP protection through the hermetically sealed cavity design.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The measuring body serves multiple functions: it measures force/load and simultaneously provides a hermetically sealed pathway for the motor cable through its integrated cable bushing. This multi-functionality eliminates the need for separate protective housing, reducing overall space consumption.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the load cell and motor cable are encapsulated in a common housing for higher IP protection, then environmental sealing is improved, but cost increases

Engineering Contradiction:

ImproveIP protectionVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The cable bushing is integrated directly into the measuring body of the load cell, merging the cable guidance function with the load cell structure itself. This eliminates the need for separate encapsulation housing, reducing space while maintaining IP protection through the hermetically sealed cavity design.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The measuring body serves multiple functions: it measures force/load and simultaneously provides a hermetically sealed pathway for the motor cable through its integrated cable bushing. This multi-functionality eliminates the need for separate protective housing, reducing overall space consumption.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If the motor cable runs through the measuring body cavity, then encapsulation is eliminated, but cable protection from environmental influences must be maintained

Engineering Contradiction:

ImproveencapsulationVSAvoidenvironmental influences

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The cavity within the measuring body is hermetically sealed to provide local protection for the motor cable against environmental influences. This localized sealing approach protects the cable without requiring external encapsulation, maintaining simplicity while ensuring protection.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The motor cable is nested within the hermetically sealed cavity of the measuring body, which itself is part of the load cell assembly. This nested structure provides protection without external encapsulation, eliminating complexity while maintaining environmental seal integrity.

Inventive Principle:

Principle #7Nested doll (Nesting)

4Measurement precision

If strain gauges are arranged on the outside of the measuring body, then measurement is enabled, but protection against environmental influences is reduced

Engineering Contradiction:

Improvestrain measurementVSAvoidenvironmental influences

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A depression is created in the measuring body at the location where strain gauge measurement is needed, providing local access for strain application while the rest of the measuring body maintains its hermetically sealed structure to protect internal components from environmental influences.

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 reduces space and cost while ensuring the motor cable remains protected from environmental influences, allowing for accurate weight measurement without force shunts and facilitating easy replacement of the load cell.

Implementation Method 1

a deformation of the measuring body caused by the weight of an item to be weighed is measured by means of one or more strain gauges

Methodology Applied

Scientific EffectStrain gauge measurement: Piezoresistive Effect

Data Source

PatentEP2581720B1Weighing cell

Publication Date: 2014.08.27 BIZERBA GMBH & CO KG

Figure 1
Figure 2

AI summary

The load cell (11) has a deformable resilient measuring body (13) formed as a bending rod, which comprises a hinge portion (23) that is arranged between a force receiving portion (15) and a force applying portion (17). The hinge portion comprises an outside connection hole that is hermetically sealed by a resilient lid. Strain gauges (31) are arranged at the hinge portion and at an outer side of the measuring body. The measuring body comprises an integrated motor cable lead-through (35) that is extended from a force receiving side to a force applying side through the hole.