Stapler Refill Sidewall Structure to Prevent Staple Sheet Blocking

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Solution Overview

Problem

Existing refills for electric staplers experience blocking issues where staple sheets adhere to each other, preventing successful feeding during the stapling process.

Innovation Solution

The refill design includes inclined walls on either side, angled in the axial direction, with at least part of these walls at the same height from the bottom surface, facilitating staple sheet separation and preventing adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If staple sheets are stacked closely together in the refill, then the refill capacity is improved, but adhesion between staple sheets occurs causing blocking

Engineering Contradiction:
Improverefill capacityVSAvoidfeeding reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The side walls are divided into multiple sections: a lower section that is inclined to separate staple sheets, and an upper section that is vertical to contain them. This segmentation allows the refill to both accommodate multiple staple sheets and prevent their adhesion through the inclined portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The side walls are designed with inclination in the axial direction (stacking direction) rather than only in the discharge direction. This dimensional change in wall orientation creates separation between staple sheets stacked in the axial direction, preventing adhesion while maintaining refill capacity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the refill structure is simplified, then the manufacturing cost is reduced, but blocking occurs due to lack of separation mechanism

Engineering Contradiction:
Improverefill manufacturingVSAvoidstaple sheet feeding
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The separating function and containing function are merged into a single side wall structure. The side wall simultaneously performs separation (through its inclined lower portion) and containment (through its upper vertical portion), eliminating the need for separate separation mechanisms and simplifying manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The side walls incorporate inclined surfaces that create a gradual transition rather than sharp angles. This curved/angled design facilitates smooth separation of staple sheets while maintaining structural simplicity and ease of manufacture.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Device complexity

If staple sheets are discharged horizontally, then the discharge mechanism is simplified, but adhesion between sheets occurs during discharge

Engineering Contradiction:
Improvedischarge mechanismVSAvoiddischarge reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The inclined side walls perform preliminary separation action on staple sheets before they reach the discharge opening. By separating sheets in advance during their passage through the refill, the discharge mechanism remains simple while adhesion is prevented beforehand.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4470737B1refill
Publication Date: 2025.12.31 MAX CO LTD
  • EP4470737B1 patent drawingFigure 1A
  • EP4470737B1 patent drawingFigure 1B
  • EP4470737B1 patent drawingFigure 2A~2B

AI summary

A refill includes: a bottom wall; a first side wall; a second side wall; and a front wall in which a discharge opening is formed. The first side wall includes, in a part thereof in a stacking direction, a first inclined wall extending in a coupling direction of staples and inclined in an axial direction. The second side wall includes, in a part thereof in the stacking direction, a second inclined wall extending in the coupling direction of the staples and inclined in the axial direction. The first inclined wall and the second inclined wall are inclined in the same direction, and at least a part of the first inclined wall and at least a part of the second inclined wall are formed at the same height from a bottom surface of the bottom wall in the stacking direction.