Work Tool Housing Shell With Elastic Impact Absorption

Solution Overview

Problem

The structural complexity and cost of adding an additional elastic component to the housing of work apparatuses, particularly battery-powered ones, to absorb impact energy are high due to the increased weight and changed centroid.

Innovation Solution

A handheld work apparatus design featuring a housing with a rib structure reinforcement and an adjacent elastic expansion region, allowing for energy absorption without an additional elastic component, using glass-fiber-reinforced plastic for the housing shells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an additional elastic component is added to the housing to absorb impact energy, then the energy absorption capability is improved, but the structural complexity and manufacturing cost increase

Engineering Contradiction:

Improveimpact energy absorptionVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the elastic expansion region directly into the housing shell structure, eliminating the need for separate elastic components. The housing shell itself is designed with regions of varying rigidity to provide both structural support and impact energy absorption functionality in a single integrated component.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The housing shell is designed with spatially varying properties: rigid regions provide structural support and guidance, while elastic expansion regions provide impact energy absorption. This local differentiation of mechanical properties allows the housing to fulfill multiple functions without requiring additional components.

Inventive Principle:

Principle #3Local quality

2Reliability

If an additional elastic component is added to the housing to absorb impact energy, then the energy absorption capability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improveimpact energy absorptionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the elastic expansion region directly into the housing shell structure, eliminating the need for separate elastic components. The housing shell itself is designed with regions of varying rigidity to provide both structural support and impact energy absorption functionality in a single integrated component.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the rigidity parameter of different regions of the housing shell to create elastic expansion regions. By varying the rigidity of the housing material or structure in specific areas, the design achieves impact energy absorption without requiring additional elastic components, thereby reducing manufacturing cost.

Inventive Principle:

Principle #35Parameter changes

3Strength

If a hard material is used for the housing to ensure guiding rigidity, then the structural integrity is improved, but the flexibility for impact absorption deteriorates

Engineering Contradiction:

Improveguiding rigidityVSAvoidimpact energy absorption

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The housing shell is designed with spatially varying properties: rigid regions provide structural support and guidance, while elastic expansion regions provide impact energy absorption. This local differentiation of mechanical properties allows the housing to fulfill multiple functions without requiring additional components.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The housing shell is segmented into different functional regions with distinct mechanical properties. Rigid regions maintain structural integrity and guiding rigidity, while elastic expansion regions provide flexibility for impact energy absorption. This segmentation allows the housing to simultaneously achieve both strength and flexibility requirements.

Inventive Principle:

Principle #1Segmentation

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 design enables cost-effective energy absorption during impacts, maintaining structural integrity and operator comfort by using a hard material for the housing while allowing flexibility in the elastic expansion region.

Implementation Method 1

an interconnected elastic expansion region for an elastic absorption of energy released in an event of an impact of the work apparatus

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS12397409B2Handheld work apparatus

Publication Date: 2025.08.26 ANDREAS STIHL AG & CO KG

AI summary

A handheld work apparatus includes a housing and a work tool arranged on the front end. The housing has a back end to which an operator region is assigned. The housing has a first and a second shell separable in a separation direction. The operator region, in the region of the back end, is bounded by a tubular section of an outer housing wall. The outer wall of the first shell is reinforced in the region of the tubular section by a rib structure inside the housing. In a view in the separation direction of the inner side of the first shell, in the region of the tubular section, the first shell has an interconnected rigid rib region and an interconnected elastic expansion region. The expansion region is directly adjacent to the rib region and is at a greater distance from the back end than the rib region.