Capacitive Proximity Sensor for Hands-Free Web Material Dispenser

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Solution Overview

Problem

Existing manually operated roll dispensers for paper towels require direct hand contact, leading to user reluctance due to concerns about contamination, while contactless dispensers with proximity sensors and motorized systems are costly and not economically viable.

Innovation Solution

A low-cost, contactless dispenser using a capacitive sensor and motorized feed mechanism that detects user proximity without direct physical interaction, allowing hands-free operation and adjustable sensitivity to accommodate varying environmental interferences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If manually operated dispensers with levers are used, then the dispensing mechanism is simple and low-cost, but users must have direct hand contact which causes contamination concerns

Engineering Contradiction:

Improvedispensing mechanism simplicityVSAvoidcontamination risk

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the manual mechanical lever system with a capacitive sensing system that detects hand proximity through electrical field changes. The capacitive sensor detects changes in capacitance when a hand approaches, triggering a motorized feed mechanism to dispense material without requiring physical contact with the dispenser body.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a capacitive sensor as an intermediary between the user's hand and the dispensing mechanism. The sensor detects the presence of a hand through electrical field interaction without requiring direct contact, and triggers the feed mechanism through an electrical control system, thus mediating the interaction to eliminate contamination risk.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If contactless dispensers with proximity sensors and motorized feed mechanisms are used, then hand contact is eliminated, but the cost and complexity increase significantly

Engineering Contradiction:

Improvecontamination riskVSAvoidsensor and motorized system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs a capacitive sensor that is relatively simple and inexpensive compared to other proximity sensing technologies. The sensor can be implemented as a simple conductive element or antenna structure that detects capacitance changes, providing a cost-effective contactless solution without requiring complex electronic components.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent utilizes changes in electrical capacitance parameter to detect hand proximity. By monitoring capacitance variations in the sensing field, the system can detect the presence of a user's hand and trigger dispensing without requiring complex mechanical or optical sensing systems, thus reducing overall device complexity.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If capacitive sensors are used for contactless operation, then hands-free dispensing is achieved, but environmental capacitive interference affects sensor accuracy

Engineering Contradiction:

Improvehands-free operationVSAvoidsensor detection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the capacitive sensor continuously monitors the electrical field and adjusts its operation based on detected capacitance changes. The control system processes the sensor signal and triggers the feed mechanism only when a valid hand proximity detection is confirmed, filtering out false signals from environmental interference.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent employs a dynamic sensing approach where the capacitive sensor's detection threshold and sensitivity can be adjusted based on environmental conditions. The system adapts to varying capacitive backgrounds by modifying its operation parameters, allowing reliable hand detection despite changes in the electrical environment.

Inventive Principle:

Principle #15Dynamics

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

Enables cost-effective, hands-free dispensing of web materials with reduced maintenance and operational costs, accommodating different environments and material types without the need for expensive electronic components.

Implementation Method 1

A capacitive sensor is connected to the feed mechanism and configured to allow touch-less operation of the dispenser

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9867509B2Dispenser with capacitive-based proximity sensor

Publication Date: 2018.01.16 SAN JAMAR INC

AI summary

A dispenser assembly for web materials includes an enclosure that is configured to support a roll of material and a feed mechanism configured to dispense the material from the assembly. A capacitive sensor is connected to the feed mechanism and configured to allow touch-less operation of the dispenser. Operation of the sensor is adjustable so that the assembly can achieve a desired operation in environments having different capacitive backgrounds.