Portable Tool Coil Feed Layout for Piston Power Continuity

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Solution Overview

Problem

Existing portable electric tools face issues such as reduced service life, weak output, and high weight due to wear of coils and battery charge limitations during intensive use.

Innovation Solution

A power supply device for portable electric tools featuring a fixed and movable coil configuration with power routing means secured to the piston, ensuring continuous power supply via a scraper contact between the coil and casing, allowing series power delivery over a defined distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a movable coil is used in the piston to improve power output, then the power output is improved, but the service life is reduced due to coil wear

Engineering Contradiction:
Improvepower outputVSAvoidservice life
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The coil system is segmented into a fixed coil (4) mounted on the cylinder and a movable coil (5) mounted on the piston. This segmentation allows the movable coil to be shorter and less prone to wear while still providing the necessary power output through electromagnetic interaction with the fixed coil.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fixed coil acts as an intermediary element that remains stationary and provides a stable electromagnetic field. The movable coil interacts with this field without needing to be a complete coil itself, reducing its complexity and wear while maintaining power output.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of moving object

If a long power supply routing means is used to supply power over the full stroke distance, then power supply is maintained, but the device complexity increases

Engineering Contradiction:
Improvepower supply durationVSAvoidpower supply routing complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The power supply routing means (61, 62) is extracted from the piston and mounted on the cylinder instead. This allows the routing means to remain stationary while still providing continuous power supply to the movable coil throughout the piston's stroke distance, reducing complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fixed coil (4) serves as an intermediary that remains stationary and provides the electromagnetic field throughout the piston's stroke. This eliminates the need for complex power routing within the moving piston, as power can be supplied through the stationary routing means.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enhances the service life and output of the tool by maintaining consistent power delivery, reducing wear, and optimizing battery usage.

Implementation Method 1

the second, movable coil 5 is supplied with power over a distance X equal to said distance D by means of a scraper contact 75 between an internal face (401, 402) of the casing 40 and the movable coil 5

Methodology Applied
Scientific EffectScraper contact: Friction

Implementation Method 2

a first, fixed coil 4 located in the cylinder 10 at the start of travel of the movable piston 1; a second, movable coil 5 located facing the first, fixed coil 4 and secured to the movable piston 1

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4399055B1Coil feeding device for electroportable tools
Publication Date: 2026.03.18 ILLINOIS TOOL WORKS INC
  • EP4399055B1 patent drawingFigure 1~2

AI summary

The present disclosure relates to a power supply device for coils for a portable electric tool (20), said portable electric tool comprising a casing (40) forming a cylinder (10) in which a movable piston (1) slides between a start position at the start of travel of the piston and an end position at the end of travel of the piston. More specifically, the power supply device comprises: at least one battery intended to supply power to the coils; a first, fixed coil (4) located in the cylinder (10) at the start of travel of the movable piston (1); a second, movable coil (5) located facing the first, fixed coil (4) and secured to the movable piston (1); and power supply routing means (61, 62) for the second, movable coil (5), these means being secured to the piston and intended to channel the power supply from the battery so as to supply power, preferably in series, to the first, fixed coil (4) and the second, movable coil (5). Each power supply routing means being configured to cooperate with connectors (71, 72), each of which is connected to one and the same terminal of the battery over at least a displacement distance (X) of the piston between the start position and the end position of the piston, said distance (X) being less than or equal to a distance (D) corresponding to the maximum distance travelled by the piston between the start position and the end position.