Hands-Free Sheet Dispenser Charge Drainage for Stable Hand Sensing

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Solution Overview

Problem

Metallic objects or surfaces near hand sensors in hands-free dispensers can interfere with sensor performance, causing decreased sensitivity, hypersensitivity, spontaneous shutdown, and uncontrolled dispensing due to static electricity and double feeding of absorbent sheets.

Innovation Solution

A conductive path is established between interfering metal surfaces and a charge receiver, positioned further away from the hand sensor, using a conductive wire or element encased in insulating material, connected to the battery compartment or other internal charge receiver, to draw charge away from these surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a metallic outer surface (e.g., nickel-plated) is used on the dispenser cover, then the dispenser has an aesthetically pleasing appearance and durable surface, but the capacitive hand sensor performance is adversely affected (decreased sensitivity, hypersensitivity, spontaneous shutdown)

Engineering Contradiction:

Improveaesthetic appearanceVSAvoidhand sensor performance

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

A conductive element (wire, spring, or bracket) is introduced as an intermediary to create a dedicated charge drainage path from the metal surfaces to the charge receiver, separating the aesthetic function of the metal cover from its harmful electrostatic effect on the sensor

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful static charge is extracted from the metal surfaces near the sensor by providing a conductive path to a remote charge receiver (battery compartment), removing the adverse effect while preserving the metal surface's aesthetic and structural functions

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of manufacture

If metal surfaces are present near the hand sensor, then the dispenser can have a metallic outer surface and internal metal components, but static electricity accumulates on these surfaces causing double feeding, spontaneous shutdown, and uncontrolled dispensing

Engineering Contradiction:

Improvemetal surface utilizationVSAvoidstatic electricity interference

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The naturally conductive metal surfaces that accumulate harmful static charge are converted into useful charge collection points by connecting them to the charge receiver, transforming the harmful static accumulation into a beneficial charge drainage function

Inventive Principle:

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

Solution Approach 2:

A conductive element serves as an intermediary pathway to channel static charge away from critical areas (sensor vicinity) to safe discharge locations (battery compartment), mediating between the metal surfaces and the charge receiver

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a conductive path is provided from metal surfaces to a charge receiver, then hand sensor performance improves and static interference is reduced, but the device complexity increases due to additional conductive elements and wiring

Engineering Contradiction:

Improvehand sensor performanceVSAvoidconductive path structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The battery compartment serves multiple functions: power supply for the dispenser and charge receiver for the conductive path, eliminating the need for a separate grounding system or additional power sources

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The conductive path integration merges the charge drainage function with existing dispenser components (battery compartment, motor housing), reducing the need for separate grounding structures and simplifying the overall device architecture

Inventive Principle:

Principle #5Merging (Combining)

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 solution improves hand sensor performance by reducing interference from metallic surfaces, preventing shutdowns and uncontrolled dispensing, while maintaining a self-contained and uncomplicated installation process.

Implementation Method 1

a conductive wire mounted inside the dispenser housing and electrically connected at one end to both a metallized dispenser cover and a rotating aluminum pinch roll

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 2

hands-free dispensers utilizing capacitive proximity sensors for hand detection

Methodology Applied

Scientific EffectCapacitive Proximity Detection: Capacitance

Data Source

PatentUS9986874B2Absorbent sheet dispenser having improved hand sensor performance

Publication Date: 2018.06.05 ESSITY PROFESSIONAL HYGIENE NORTH AMERICA LLC

AI summary

A hands-free dispenser for dispensing lengths of absorbent sheet products, includes: a dispenser body containing a dispensing mechanism; a hand sensor for detecting the presence of a user's hand in the vicinity of the dispenser; an elongated metallic conductive element having a proximate end in electrical communication with at least one metal surface of the dispenser positioned at a first location relative to the hand sensor, and a distal end in electrical communication with at least one charge receiver positioned at a second location relative to the hand sensor, the second location being at a greater distance from the hand sensor than the first location.