Paper Towel Dispenser Roll-Speed Sensing for Low Material Alerts
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Solution Overview
Problem
Automatic sheet material dispensers, such as paper towel dispensers, face challenges in determining the remaining amount of sheet material, making it difficult to assess when a replacement roll is needed, as the roll is obscured within the dispenser housing, leading to inconvenient and time-consuming manual checks.
Innovation Solution
A low-material sensing system comprising a sensor, motor, and controller that detects the rotational speed of the sheet material roll and motor, using a bar code sensor and microcontroller with an A/D converter to provide an indication when the roll is nearing depletion, allowing for visual or audible alerts without opening the dispenser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual checking of sheet material roll is used, then the attendant can determine the remaining material, but it requires opening the dispenser which is time-consuming and inconvenient
Solution Approach 1:
The patent replaces the manual mechanical inspection method with an automated optical sensing system. A bar code sensor detects a machine-readable code on the roll core, and a motor sensor monitors motor current/voltage to calculate rotational speed. This substitution eliminates the need to manually open the dispenser, resolving the contradiction between accurate detection and time loss.
2Ease of operation
If the roll is made visible in the dispenser, then the attendant can easily see the material level, but the dispenser housing must be transparent which may compromise protection and design
Solution Approach 1:
The patent introduces an intermediary sensing system that indirectly measures material levels without requiring visual transparency. The bar code sensor and motor sensor act as intermediaries, detecting roll characteristics and rotational speed to infer material remaining. This allows the housing to remain opaque for protection while still providing easy monitoring through automated sensing.
3Measurement precision
If an angular displacement measurement system is used to detect low material state, then the material level can be measured, but the system lacks accuracy and requires additional parts that increase cost
Solution Approach 1:
The patent makes the existing motor and bar code sensor serve multiple functions. The motor is used both for its primary function of driving the roll and as a sensor through monitoring its current/voltage and rotational speed. The bar code sensor is used both for roll identification and for detecting rotational speed to calculate material remaining. This multi-functionality eliminates the need for separate angular displacement sensors, reducing complexity and cost while maintaining measurement precision.
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 quick and efficient determination of when a sheet material roll is low or depleted, reducing manual checks and ensuring continuous operation by alerting attendants to replace the roll, thus maintaining dispenser functionality without increasing costs.
Implementation Method 1
using a bar code sensor and microcontroller with an A/D converter to provide an indication when the roll is nearing depletion
Implementation Method 2
The motor has an armature and produces movement of the sheet material when current is supplied to the motor
Data Source
AI summary
Apparatus, systems and methods for dispensing sheet material from a roll which include a low-material sensing system. The low-material sensing system provides an indication when the sheet material approaches depletion or is depleted so that the depleted sheet material roll can be replaced with a full roll. The low-material sensing system determines that the sheet material is depleted or near depletion by comparing the rotational speed of a sheet material roll from which the sheet material is unwound with the speed of the motor which produces movement of the sheet material roll when power is supplied to the motor. The sheet material roll speed increases as material is unwound while the motor speed remains relatively constant. A low-material indication is provided when the comparison reaches a threshold representative of the low-material state.