Energy Absorbing Device for Powered Tool Impact Protection

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Solution Overview

Problem

Powered devices, such as mowers, experience damage from impact energy when their working members, like cutting blades, strike obstacles, leading to potential damage to actuators and other components due to unabsorbed force, which existing torque-limiting couplings fail to adequately mitigate.

Innovation Solution

An energy absorbing device (EAD) is interposed between the motor housing and the structural member of powered devices, comprising a plastically deformable structure, such as an annulus with extensions or a corrugated sheet-like material, to absorb impact energy by deforming plastically, thereby reducing the force transmitted to other components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid coupling is used between the actuator housing and structural member, then structural strength is maintained, but impact energy damages the actuator and components

Engineering Contradiction:

Improveactuator protection from impact damageVSAvoidstructural coupling strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies beforehand cushioning by incorporating an energy absorbing device (EAD) between the actuator housing and structural member. The EAD is pre-configured with plastically deformable structures (such as corrugated sheets, foam layers, or lattice structures) that are designed to deform and absorb impact energy before it reaches the actuator, thereby protecting the actuator from damage while maintaining structural integrity during normal operation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent uses an intermediary approach by introducing an energy absorbing device as a mediator between the actuator housing and structural member. This EAD acts as a buffer that absorbs and dissipates impact energy through plastic deformation of its internal structures (corrugated sheets, foam, lattice), preventing direct transmission of harmful forces to the actuator while maintaining the structural coupling

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a torque-limiting coupling is used, then some impact protection is provided, but it fails to adequately mitigate off-axis impact loads

Engineering Contradiction:

Improveimpact energy absorptionVSAvoidcoupling mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by designing the EAD with specific geometric parameters (corrugation patterns, foam density, lattice structures) that enable it to absorb impact energy effectively. The EAD's physical parameters (material properties, structural geometry) are optimized to deform plastically under impact loads, converting kinetic energy into deformation energy and thereby protecting the actuator from both axial and off-axis impact forces

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the working member strikes an obstacle, then cutting function is performed, but impact energy damages the actuator and structural components

Engineering Contradiction:

Improvecutting operation capabilityVSAvoidimpact energy damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the blessing in disguise principle by converting the harmful impact energy from obstacle strikes into beneficial plastic deformation of the EAD structures. When the working member (cutting blade) strikes an obstacle, the impact energy that would normally damage the actuator is instead absorbed by the corrugated sheets, foam, or lattice structures of the EAD, which deform plastically to dissipate the energy, thereby protecting the actuator while allowing the cutting operation to continue

Inventive Principle:

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

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 EAD effectively reduces the impact energy transferred to the motor housing and other components, potentially preventing damage and extending the lifespan of the device by absorbing a significant portion of the impact energy, thus minimizing the need for costly replacements.

Implementation Method 1

the EAD to absorb the portion of the impact energy by being plastically deformed by the portion of the impact energy

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS20230027760A1Energy absorbing devices

Publication Date: 2023.01.26 ACCELERATED SYST

AI summary

There is provided a powered device and an energy absorbing device (EAD) for a powered device. The powered device includes an actuator to power a rotatable shaft coupled to a working member, a housing to house the actuator, a structural member to be coupled to the housing, and an EAD. The EAD is disposed between the housing and the structural member. The EAD is to absorb at least a portion of an impact energy of the working member striking an obstacle. Moreover, the EAD is to absorb the portion of the impact energy by being plastically deformed by the portion of the impact energy.