Blower-Vacuum Two-Step Grill Lock to Prevent Accidental Fan Exposure

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Solution Overview

Problem

Existing blower-vacuum devices lack a secure mechanism to prevent inadvertent exposure of the fan assembly during mode conversion, risking accidental activation and user injury.

Innovation Solution

A locking mechanism involving a rotatable grill cover with a two-step process: initial closure and subsequent rotation to engage a safety switch, utilizing an outer ring and inner cover with a pin and slot or boss and actuator, ensuring the motor can only be actuated when the grill or vacuum tube is securely locked in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a simple grill cover is used to block access to the fan, then the device is easy to operate and convert between modes, but the fan may be inadvertently exposed during mode conversion causing safety hazards

Engineering Contradiction:
Improveease of mode conversionVSAvoidaccidental fan exposure
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The safety switch is activated in advance by the rotation of the grill cover before the motor can be started. This preliminary action ensures that the grill is properly positioned and secured before the fan becomes operational, preventing accidental exposure while maintaining ease of operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The safety switch acts as an intermediary mechanism between the grill cover position and the motor operation. It mediates the control signal to ensure the motor only operates when the grill is properly closed and secured, eliminating the safety hazard without complicating the mode conversion process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a locked position mechanism is added to ensure the grill remains secured, then fan exposure is prevented, but the device complexity increases

Engineering Contradiction:
Improvefan exposure preventionVSAvoidlocking mechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The safety switch activation is merged with the existing grill cover rotation operation. The same rotational motion that secures the grill in place also activates the safety switch, combining two functions into one action. This prevents fan exposure without adding separate locking mechanisms or increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3620045B1Blowervac safety grille
Publication Date: 2024.03.27 BLACK & DECKER CORP
  • EP3620045B1 patent drawingFigure 1
  • EP3620045B1 patent drawingFigure 2
  • EP3620045B1 patent drawingFigure 3

AI summary

The present invention is directed to a blowervac device having a grill (18) that requires to distinct steps in securing the grill (18) over a fan (24) to activate a safety switch (60) allowing power to the motor. The grill (18) has an outer ring (42) and a rotatable inner cover (44). The first step is simply to secure the grill (18) over the fan (24). The second step requires the cover (44) to be rotated, which activates an actuator (62) for the safety switch (60), allowing power to be delivered to the motor and operation of the device. This two-step process reduces the likelihood if inadvertent operation of the device and reduces the chances of injury