Battery Pack State of Charge Indicator via Locking Mechanism

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing battery packs for hand tools face issues with increased manufacturing costs and sealing problems due to protruding push buttons, and they often lead to unnecessary battery discharge, as operators may forget to check the charge status, resulting in missed charging opportunities and inconvenient work interruptions.

Innovation Solution

Integrating the state of charge display switching means into the locking mechanism's actuating means, allowing for controlled activation of the charge status display without additional housing openings, and incorporating a timer to prevent permanent activation, thus reducing unnecessary discharge and ensuring regular awareness of the battery's state of charge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a push button protruding from the housing is used to activate the charge status display, then the state of charge can be checked on demand, but manufacturing costs increase and sealing problems occur

Engineering Contradiction:
Improvecharge status display activationVSAvoidhousing sealing and manufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent combines the locking mechanism and the charge status display activation into a single integrated system. The locking element serves dual purposes: securing the battery pack to the power tool and activating the charge status display when actuated. This eliminates the need for a separate protruding push button, thereby maintaining ease of operation while improving manufacturing ease and sealing integrity.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If a push button protruding from the housing is used to activate the charge status display, then the state of charge can be checked on demand, but the push button may be broken off during use

Engineering Contradiction:
Improvecharge status display activationVSAvoidpush button durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking mechanism and display activation are merged into one robust component. The locking element, designed to withstand mechanical forces during tool attachment and detachment, now also serves as the activation mechanism. This integration eliminates the vulnerability of a separate protruding push button that could break off during use.

Inventive Principle:
Principle #5Merging (Combining)

3Loss of energy

If a charge status display that can be activated as required is used, then unnecessary discharge during standstill is avoided, but operators may forget to check the charge status

Engineering Contradiction:
Improvebattery discharge during standstillVSAvoidcharge status awareness
Core Design Contradiction:
Loss of energyVSLoss of information

Solution Approach 1:

The system performs a preliminary action by automatically displaying the charge status at the moment the operator detaches the battery pack from the power tool. This timing ensures the operator is immediately informed of the charge level before leaving the tool, eliminating the need to remember to check later while still avoiding continuous discharge during standstill.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system provides feedback about the charge status at a critical moment - when the battery pack is removed from the tool. This feedback mechanism ensures the operator is always informed of the charge level at the point of potential recharging, preventing forgotten checks while maintaining energy efficiency during idle periods.

Inventive Principle:
Principle #23Feedback

4Ease of operation

If additional switching means are added to the housing for the charge status display, then the display can be activated, but manufacturing costs increase

Engineering Contradiction:
Improvecharge status display activationVSAvoidhousing modifications and cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The locking element is designed with multi-functionality, serving both as a mechanical securing device and as an activation switch for the charge status display. This universal design eliminates the need for additional switching means and housing modifications, thereby maintaining ease of operation while significantly reducing manufacturing complexity and cost.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP1772943B1Battery pack with state of charge indicator
Publication Date: 2014.10.29 HILTI AG
  • EP1772943B1 patent drawingFigure 1
  • EP1772943B1 patent drawingFigure 2

AI summary

A battery pack (2) for a hand tool comprises a housing (4) containing several battery cells (28) and featuring externally accessible coupling means (18) electrically connected to the battery cells (28), and a charge status indicator (22) that can be activated via externally accessible external switching means and indicates the charge status of the battery cells (28). The external switching means are formed by actuating means (16) of a locking mechanism (14) of the battery pack (2).