Staple Pusher Assembly with Coiled Constant Force Spring

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Solution Overview

Problem

Existing staple pusher assemblies in staplers often require additional space for the coiled end of constant force springs, making them less efficient in terms of design and installation, and typically involve complex and time-consuming procedures for assembly.

Innovation Solution

A staple pusher assembly with a coiled constant force spring positioned within a cavity of the staple pusher, eliminating the need for additional space and allowing for a unitized assembly that is easier to install and use, featuring a coiled end retained without any shaft or projection within the cavity, and a coupling mechanism for secure attachment to the magazine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the coiled end of the constant force spring is positioned outside the staple pusher, then there is sufficient space for the spring, but additional space is required making the design less efficient

Engineering Contradiction:

Improvespace efficiencyVSAvoidassembly complexity

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The coiled end of the constant force spring is positioned inside the hollow cavity of the staple pusher, nesting one component within another. This eliminates the need for additional external space while maintaining spring functionality, directly resolving the contradiction between space efficiency and assembly complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The staple pusher and constant force spring are designed as a unitized assembly where the spring's coiled end is retained within the pusher's cavity. This merging of components into a single integrated unit improves space efficiency and simplifies installation as one piece, addressing both aspects of the contradiction.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If traditional spring arrangements are used, then the spring can provide constant force, but the assembly process is complex and time-consuming

Engineering Contradiction:

Improveassembly easeVSAvoidassembly time

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The staple pusher and constant force spring are manufactured and assembled as a unitized assembly in advance. This pre-assembly eliminates complex installation procedures during stapler assembly, making the process easier and faster while maintaining the constant force functionality of the spring.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The constant force spring is pre-positioned within the staple pusher cavity during manufacturing, rather than being installed separately during assembly. This preliminary action simplifies the final assembly process and reduces installation time, directly addressing the contradiction between assembly ease and time loss.

Inventive Principle:

Principle #10Preliminary action

3Volume of moving object

If the coiled end of the spring is retained without a shaft or projection, then space is saved, but the retention mechanism must be simplified

Engineering Contradiction:

Improvecavity space utilizationVSAvoidspring retention reliability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The coiled end of the spring is nested within the hollow cavity of the staple pusher without requiring shafts or projections. The cavity walls themselves provide the retention structure, saving space while maintaining reliability through the simple containment geometry.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The hollow cavity of the staple pusher serves dual purposes: it provides structural support and automatically retains the coiled end of the spring through its geometric constraints. This self-service design eliminates the need for additional retention features like shafts or projections, saving space while ensuring reliable spring positioning.

Inventive Principle:

Principle #25Self-service

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 design achieves space savings, simplifies the assembly process, and ensures a constant force for staple ejection regardless of the staple count, while being quieter and more user-friendly compared to traditional spring arrangements.

Implementation Method 1

a constant force spring having a first end coupled to the magazine and a second end that is coiled within the cavity in the staple pusher

Methodology Applied

Scientific EffectConstant force spring: Spring

Data Source

PatentUS11267117B2Staple pusher assembly and method of installing same

Publication Date: 2022.03.08 ACCO BRANDS CORP

AI summary

A stapler includes a base, a magazine coupled to the base and configured to house staples, and a staple pusher assembly coupled with the magazine and operable to bias staples in the magazine toward a first end of the magazine where staples are driven out of the magazine. The staple pusher assembly includes a staple pusher defining a cavity, and a constant force spring having a first end coupled to the magazine and a second end that is coiled within the cavity in the staple pusher.