Sheet Dispenser Cutting Mechanism for Low-Pull Single-Sheet Dispensing

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Solution Overview

Problem

Existing sheet material dispensers require a high pull force to initiate a dispense cycle, leading to issues like 'tabbing' and excessive material usage, and lack the ability to adjust the tail length for user convenience and conservation.

Innovation Solution

The dispenser features a cutting mechanism with a serrated blade and blade carrier, which reduces the required pull force and includes a tail length adjustment mechanism, allowing for customizable tail length and encouraging single-sheet usage through a controlled dispense cycle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a high spring force is used to power the drive roller and cutting mechanism, then the sheet material can be fully or partially severed to provide a single sheet, but the pull force required to initiate a dispense cycle increases to two pounds or more

Engineering Contradiction:

Improvespring forceVSAvoidpull force required

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The cutting mechanism is segmented into a cutting element and a non-cutting element, allowing the web to be severed without requiring high spring force to power a rotating cutting mechanism. The cutting element is positioned to engage the web at a specific point during roller rotation, enabling cutting with minimal additional force.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a high-force spring mechanism to power rotation and cutting, the invention inverts the approach by using a low-force spring mechanism that simply rotates the roller a limited amount, relying on the cutting element's positioning and geometry to accomplish severing with minimal force.

Inventive Principle:

Principle #13The other way round (Inversion)

2Force

If a high pull force of two pounds or more is required to initiate a dispense cycle, then the drive roller can be rotated to power the cutting mechanism, but tabbing occurs where a small portion of the sheet material tail tears off in the user's hand

Engineering Contradiction:

Improvepull forceVSAvoidtabbing prevention

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The invention inverts the conventional approach by using a low-force spring mechanism instead of high-force springs, reducing the pull force requirement and eliminating tabbing caused by excessive force on the tail.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The spring force parameter is changed from high force to low force, fundamentally altering the operational characteristics of the dispenser to prevent tabbing while maintaining effective sheet severing through the cutting element design.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the dispenser allows repeated and immediate cycling to dispense multiple sheets, then user convenience is improved, but sheet material conservation is reduced leading to increased cost and waste

Engineering Contradiction:

Improvedispense cycle rateVSAvoidsheet material waste

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The dispenser dynamically adjusts between two operational modes: a first mode allowing repeated immediate cycling for multiple sheets, and a second mode limiting cycling to one sheet at a time. This dynamic behavior allows the system to adapt to different user needs while promoting conservation when appropriate.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The dispenser implements periodic action by introducing a time delay between dispense cycles in the second mode, preventing immediate repeated cycling and encouraging single-sheet usage, thereby reducing material waste while still allowing multiple sheets to be dispensed if needed.

Inventive Principle:

Principle #19Periodic action

4Ease of operation

If the tail length is increased to make it easier to grasp for users, then ease of operation improves, but the dispenser structure must be modified to accommodate variable tail lengths

Engineering Contradiction:

Improvetail graspabilityVSAvoidtail length adjustment mechanism

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The dispenser incorporates a dynamic tail length adjustment mechanism that allows the tail to be extended to different lengths based on user needs. The mechanism dynamically positions the tail extension between a retracted position and an extended position, accommodating varying graspability requirements.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8733218B2Sheet material dispenser

Publication Date: 2014.05.27 ALWIN MFG CO INC

AI summary

Apparatus for dispensing sheet material from a sheet material dispenser are described. Dispenser embodiments include drive and tension rollers supported within a housing forming a nip therebetween. Pulling of sheet material through the nip and against the drive roller rotates the drive roller. Dispenser embodiments may include a cutting mechanism powered by drive roller rotation with an improved carrier-supported blade permitting highly-efficient dispenser operation. Dispenser embodiments may include a sheet material tail length adjuster which permits the attendant to shorten or lengthen the tail length extending away from the dispenser. Dispenser embodiments may further include a sheet material conservation feature which imposes a delay between dispense cycles encouraging use of a single sheet of material and discouraging sheet material waste.