Utility Blade Retention via Detent Interlocking
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Solution Overview
Problem
Modern utility knives often experience issues with the utility blade being pulled out of the blade carrier during use due to insufficient retention mechanisms, which limits the exposed cutting edge length.
Innovation Solution
A utility blade with a convex quadrilateral shape and a holder featuring a blade carrier with detents and openings that securely position and hold the blade, allowing for a longer exposed cutting edge and improved retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the utility blade is mated to the blade carrier using two small U-shaped notches, then the blade can be held in the carrier, but the blade may be pulled out during use and the cutting edge length is limited
Solution Approach 1:
The blade carrier is segmented into multiple functional zones: a blade pocket for positioning, multiple detents (at least two) for retention, and an exposed cutting edge portion. This segmentation allows each zone to perform its specific function optimally - the pocket provides precise positioning, the detents provide secure retention through interlocking with blade notches, and the exposed portion maximizes cutting length.
Solution Approach 2:
The utility blade is nested within the blade carrier housing, with the blade body positioned inside the blade pocket. The blade's notches are nested with the detents to create an interlocking retention mechanism. This nesting arrangement protects the blade while allowing maximum exposure of the cutting edge.
2Reliability
If a greater amount of the utility blade is held inside the blade carrier, then the blade is more securely retained, but the length of the cutting edge that is exposed is limited
Solution Approach 1:
The blade carrier features localized retention elements (detents) positioned at specific locations within the blade pocket, rather than requiring the blade to be deeply embedded. The detents are positioned to engage with notches on the blade body at optimal locations, providing secure retention while minimizing the amount of blade length consumed inside the carrier.
Solution Approach 2:
The retention mechanism transitions from a linear depth-based retention system to a multi-point distributed retention system using detents positioned at different locations. This dimensional change allows retention force to be distributed across multiple engagement points, securing the blade without requiring deep insertion that would limit cutting edge exposure.
3Device complexity
If the blade carrier uses a simple holding mechanism, then the device complexity is reduced, but the blade may be accidentally removed during use
Solution Approach 1:
The blade pocket and detents are pre-configured in the blade carrier housing before blade installation. The detents are positioned and shaped to automatically engage with the notches on the blade body as the blade is inserted, providing immediate retention without requiring additional adjustment or complex assembly steps.
Solution Approach 2:
The interlocking mechanism between the blade notches and carrier detents is self-retaining. Once the blade is inserted, the detents automatically engage with the notches to secure the blade in place. The design allows the blade to be easily removed when needed by simply pulling it outward, providing both secure retention and ease of operation without complex locking mechanisms.
Data Source
AI summary
A utility blade is provided that includes a blade body having a convex quadrilateral shape. The blade body defines a top edge, a linear cutting edge on an opposite side of the blade body from the top edge, and a pair of side edges located on opposite sides of the blade body, extending between the top edge and the linear cutting edge. The blade body also defines a pair of openings located proximate the pair of side edges, between the top edge and the linear cutting edge; and the pair of openings are spatially separated from the top edge and the linear cutting edge. A top portion of the utility blade is contoured to fit within a holder that includes a pair of detents, and the pair of openings contoured to fit the pair of detents to position and hold the utility blade within the holder.