Power Tool Shield Assembly for Secure Quick-Change Guards
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Solution Overview
Problem
Existing power tools, such as angle grinders, often require complex and labor-intensive guard manufacturing processes, leading to durability issues and difficulty in quickly changing guards for different applications, while operators may improperly remove or reposition shields, increasing injury risk.
Innovation Solution
A shield assembly featuring a guard collar and guard member with a lock-out scheme, allowing for quick and secure attachment/detachment, and a universal adaptor design that reduces complexity and improves durability by using a ring clip for retention, ensuring compatibility with suitable guard members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex and labor-intensive guard manufacturing processes are used, then guard strength and durability are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The guard assembly is divided into separate components: a guard collar that attaches to the tool and a guard member that attaches to the collar. This segmentation allows each component to be manufactured using simpler processes while maintaining overall durability through proper interface design with engagement features.
Solution Approach 2:
The guard member is designed to fit over and nest within the guard collar structure, with the guard member circumferentially attaching to the collar through engagement features. This nested configuration reduces manufacturing complexity while preserving structural integrity.
2Strength
If traditional shield attachment methods are used, then guard strength is maintained, but ease of operation for quick guard changes deteriorates
Solution Approach 1:
The engagement features are designed to allow dynamic attachment and detachment operations. The circumferential engagement member and recess enable the guard member to be quickly attached and removed from the guard collar without complex tools, while maintaining strong attachment during use.
Solution Approach 2:
The engagement features are extracted as distinct elements: a circumferential engagement member on the guard member that mates with a circumferential recess in the guard collar. This extraction allows for simplified attachment/detachment operations while maintaining attachment strength through the dedicated engagement interface.
3Ease of operation
If guards are made easily removable for operator convenience, then ease of operation improves, but reliability and safety deteriorate due to improper removal
Solution Approach 1:
The engagement features are designed with preliminary anti-action: the circumferential engagement member and recess create a secure mechanical interlock that prevents accidental or improper removal during operation, while still allowing intentional removal when needed. The latch mechanism provides preliminary engagement that must be deliberately disengaged.
Solution Approach 2:
The engagement features are designed to be self-securing: the circumferential engagement member automatically engages with the recess and the latch secures the connection without requiring additional fastening steps. This self-service mechanism ensures proper engagement while preventing improper removal, eliminating the need for operators to make judgment calls about removal safety.
4Adaptability or versatility
If universal adaptor design is used, then adaptability for different guard members improves, but manufacturing precision requirements worsen
Solution Approach 1:
The guard collar is designed as a universal adaptor with a standardized circumferential recess that can accommodate multiple different guard members. This universality allows a single collar design to work with various guard types while maintaining reliable engagement through the consistent engagement interface geometry.
Solution Approach 2:
The circumferential recess and engagement member are designed with specific asymmetric geometries that provide tolerance compensation. The engagement features include flat surfaces and curved surfaces with defined radii that accommodate manufacturing variations while ensuring proper engagement, reducing the precision requirements compared to tight-fit designs.
Data Source
AI summary
A shield assembly includes a guard collar and a guard member. The guard collar is disposed around a neck of a gear case of a power tool and includes a first engagement interface. The first engagement interface extends along an outer perimeter of the guard collar and defines a circumferential recess. The guard member includes a second engagement interface for removably engaging with the first engagement interface to secure the guard member to the guard collar. The second engagement interface includes a circumferential engagement member for mating with the circumferential recess of the first engagement interface. The guard member includes a body portion for at least partially surrounding a working member of the power tool.