Cut-Off Saw Shroud Locking for Stable Pivoting Guard

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Solution Overview

Problem

Existing cut off saw designs lack a reliable mechanism for securely mounting and locking a shroud onto a pivoting guard, which compromises the stability and maneuverability of the saw during operation.

Innovation Solution

A power tool assembly comprising a cut off saw and a shroud with a pivotally mounted switch lever and biasing mechanism, where the shroud is locked to the guard by pivoting the switch lever to locate a peg under the guard's edge, utilizing a spring for biasing, allowing the guard to rotate around the output spindle while being securely locked in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the guard is mounted to pivot around the output spindle to improve maneuverability, then the saw becomes more manoeuvrable, but the guard becomes unstable and may move unintentionally

Engineering Contradiction:
ImprovemanoeuverabilityVSAvoidguard stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The guard is designed to be dynamically adjustable between two states: a locked stable position during cutting operations and an unlocked movable position for adjustment. The spring-loaded switch lever mechanism enables the guard to transition between these states, maintaining stability when needed while allowing maneuverability when required.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the positional parameter of the guard by introducing discrete locked positions along the pivot path. The engagement section with multiple engagement positions allows the guard to be secured at specific intervals, transforming the continuous pivot motion into discrete stable positions.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a locking mechanism is added to secure the shroud to the guard, then the guard stability improves, but the device complexity increases

Engineering Contradiction:
Improveguard stabilityVSAvoidmounting mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The spring-loaded switch lever automatically returns to the engaged position after being actuated, providing self-service functionality. The biasing mechanism ensures the locking peg automatically re-engages with the engagement section after the guard is adjusted, eliminating the need for manual resetting or complex control systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The switch lever acts as an intermediary element between the operator's manual input and the locking mechanism. By pressing the finger pad, the operator actuates the switch lever which in turn moves the locking peg to engage or disengage from the engagement section, simplifying the user interface while maintaining a reliable locking function.

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 provides a stable and secure mounting system for the shroud, allowing the guard to rotate freely while preventing unintended movement, enhancing the saw's maneuverability and operational safety.

Implementation Method 1

a biasing mechanism which biases the switch lever towards its first position

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP4129594A1Circular saw with a shroud
Publication Date: 2023.02.08 BLACK & DECKER CORP
  • EP4129594A1 patent drawingFigure 1
  • EP4129594A1 patent drawingFigure 2
  • EP4129594A1 patent drawingFigure 3

AI summary

A power tool assembly comprising a cut off saw and a shroud wherein, when the shroud (300) is mounted on the cut off saw, the guard (120) of the cut off saw is located within the shroud trough section (306) of the shroud (300); wherein the shroud (300) is locked to the guard (120) by locating the engagement section (392) under one of the lower front edge (396) or lower rear edge (398) of the guard (120) and by pivoting the switch lever (374) to its first position to locate the peg (394) under the other of the lower front edge (396) or lower rear edge (398) of the guard.