Stapler Four-Bar Linkage Reduces Input Force

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Solution Overview

Problem

Conventional staplers require significant input force to operate, leading to user fatigue and inefficiency in stapling multiple sheets of paper.

Innovation Solution

A four-bar linkage drive arrangement is implemented in the stapler, featuring an input member, a drive member, and a fixed base member, where the pivot axis of the input member moves along an arcuate path, allowing for reduced input force requirements by distributing the force effectively through an auxiliary member or a slot, enabling efficient staple ejection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a conventional stapler mechanism is used, then the stapling function is achieved, but significant input force is required leading to user fatigue

Engineering Contradiction:

Improveinput forceVSAvoiduser effort

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The patent implements a movable pivot axis that transitions from a fixed position to a moving position along an arcuate path during operation. This dynamic adjustment of the pivot axis location optimizes the mechanical advantage throughout the stapling cycle, reducing the input force required while maintaining effective stapling function

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameter of the pivot axis position dynamically during operation. By moving the pivot axis along a predetermined arcuate path, the system adjusts the lever arm lengths and force distribution in real-time, transforming the force requirements to reduce user effort

Inventive Principle:

Principle #35Parameter changes

2Force

If the pivot axis is fixed, then the mechanism is simpler, but the input force required is higher

Engineering Contradiction:

Improveinput forceVSAvoidmechanism complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The patent converts a static pivot axis into a dynamic one that moves along an arcuate path. This is achieved through a linkage mechanism comprising connecting rods and joints that guide the pivot axis movement, adding controlled complexity to reduce force requirements

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention introduces intermediary components (connecting rods, joints, and guide structures) that mediate between the fixed base and the movable pivot axis. These intermediaries enable the complex motion pattern while distributing mechanical loads, reducing the force burden on the user

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution reduces the input force needed to staple sheets to less than 9 pounds, minimizing user effort and improving operational efficiency.

Implementation Method 1

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentUS7942298B2Paper processing tool with force reducing drive arrangement

Publication Date: 2011.05.17 ACCO BRANDS USA LLC

AI summary

A stapler includes a base member, a magazine for receiving a plurality of staples, and a drive member including a driver blade movable relative to the magazine for ejecting staples from the magazine one at a time. The stapler further includes an input member pivotally coupled to the drive member. The input member is configured to receive an input force and transmit the input force to the drive member for driving movement of the drive member relative to the magazine. One of the drive member and the input member pivots about a pivot axis that moves relative to the base member along an arcuate path.